SMITHSONIAN INSTITUTIONUNITED STATES NATIONAL MUSEUM
Bulletin 89

OSTEOLOGY OF THE ARMORED DINOSAURIA IN THE
UNITED STATES NATIONAL MUSEUM, WITH
SPECIAL REFERENCE TO THE GENUS
STEGOSAURUS

CHARLES WHITNEY GILMORE
Assistant Curator of Fossil Reptiles, United States Natiotial Museum

WASHINGTON
GOVERNMENT PRINTING OFFICE
1914

BULLETIN (IF THE UNITED STATES NATIONAL MUSEUM
Issued December 31, 1914.

ADVEETISEIVIENT.
The scientific publications of the United States National Museum consist of
two series, the Proceedings and the Bulletins.
The Proceedings, the fii'st volume of which was issued in 1878, are intended
primarily as a medium for the publication of original, and usually brief, papers
based on the collections of the National Museum, presenting newly acquired facts
in zoology, geology, and anthropology, including descriptions of new forms ofanimals, and revisions of limited groups. One or two volumes are issued annuallyand distributed to libraries and scientific organizations. A limited number of copies
of each paper, in pamphlet form, is distributed to specialists and others interested
in the different subjects as soon as printed.
The date of publication is printed oneach paper, and these dates are also recorded in the tables of contents of the volume.
The Bulletins, the first of which was issued in 1875, consist of a series of separate publications comprising chieflj' monographs of large zoological groups and othergeneral systematic treaties (occasionally in several volumes), faunal works, reportsof expeditions, and catalogues of type-specimens, special collections, etc.
Themajority of the volumes are octavos, but a quarto size has been adopted in a few

instances in which large plates were regarded as indispensable.

Since 1902 a series of octavo volumes containing papers relating to the botanicalcollections of the Museum, and known as the Contributions from the National Herba-

rium, has been pubhshed as bulletins.

The present work forms No. 89 of the Bulletin series.

RiCHAKD RaTHBUN,
Assistant Secretary, Smithsonian Institution,

In charge of the United States National Museum

Washington, D. C, November, 18, 1914.

,TABLE OF CONTENTS.
Introductioni

Occurrence and history
History of Quarry 13
Plan of work
History of Quarry No. 1

o

2
o

24

Plan of work

25

Osteology of Stegosaurus^^ -^-^^' "^--!-^!!^^'!!"!!"!!!!'!!!

Skull

Summary of cranial materials
Known elements of the Stegosaurian skull
Description_

Basioccipital

_

26
26

26
27
9y
28

Exoccipital and Paraoccipital

28

Supraoccipital

2q

Basisphenoid and Presphenoid
Alisphenoid

30
oq

OrbitosphenoidoParietal

t

.,,

•.

FrontalonPrefrontal

09

Postf rontal„2

Postorbital

00

Prootic„2

Lachrymal00

Supraorbitals_

Nasals„>00

Premaxillae
Maxillae
Jugal
Quadratojugal
Quadrate

00

o^
34
„

„_

Squamosal„_

Pterygoids„„

Palatines

„„

Vomer

„„

Epipterygoid„„

Measurements of skull
Lower jaw„(„„

Dentary
Predentary„„„„

Splenial„„

Angular
Surangulargg„„

Articular„„

PrearticularCoronoid.

. . ^

„q
„„

^

Measurements of lower jaw

sy°'d

^^
;;;---;;;;;;;;;;;;;;;;;:;;:::::;;::;::40

—TABLE OF CONTENTS.

VI—

Osteology of Stegosaurus Continued.
External openings in the skull

Supratemporal fossae
Infratemporal fossae

Page.

40

'.

40

:

Orbital cavities

41

Anterior nares

41

Posterior nares

41

Palatine vacuities

41

Foramen magnum

41

Lesser foramina

41

Brain

43

Teeth

44

Vertebral column

45

Atlas

45

Axis

47

Cervicals posterior to the axia

47

Dorsal vertebrae

49

Dorso-sacral

52

Sacrum53

Caudo-sacral

Caudal vertebrae
Chevrons
Ribs

57

58

^

61
63

Cervical ribs

63

Dorsal ribs

63

Sternal bones

65

Shoulder girdle
Scapula66
66

Coracoid
Fore limb and footHiunerus

67

68
68

Ulna
RadiusFore footCarpusRadialeIntermedivun
UlnarePisiform
Metacarpus.
Phalanges

69

-

69

70
70
71
71

•.

72
72

72
75

Pelvis

77

Ilium
Pubis

77

78

Ischium
Hiad limb and foot

79

80

Femur
Tibia

80
84

Fibula85

Hind foot86

Astragalus

86

Calcaneum
Metatarsus

Phalanges
Dermal armor

Dermal ossicles

87
;

87

89
91

91

TABLE OF CONTENTS.
Osteology of Stegosaurus—

VH—Continued.

P^„g

Dermal armor Continued.
Nuchal plates^.

Dorsal plates

92
92

Caudal plates
Dermal spines
Arrangement of the armor
Morphology of plates

93
95
96

lOO

The geniia Stegosaurus

101

Generic characters

103

Description of species

104

Stegosaurus stenops Marsh

104

History of the type-specimen

106

Position of the skeleton

106

Theory of fossilization
Stegosaurus sulcaius Marsh

107

Stegosaurus longispinus, new species

Ill

Hoplitosaurus marshi (Lucas)
Dinosaur armor from the Lance formation

114

109

121

Restorations of Stegosauriis
List of works cited

122
'.
,

127

Explanation of plates

131

Index

137

.

ILLUSTRATIONS.
PLATES.
Facing page.

Plate 1. Quarrj', Garden Park, Fremont County, Colorado

136

2.

Skeleton of Stegosaurus stenops

136
136

3.

Outline of skeleton of Stegosaurus stenops

4.

Skeleton of Stegosaurus slenops, lower side

136

5.

Skull of Stegosaurus stenops, side view

136

6.

Skull of Stegosaurus stenops, top view

136

7.

Skull of Stegosaurus stenops, inferior view
Skull of Stegosaurus stenops, longitudinal section

136

8.

9.

Skull of Stegosaurus stenops, anterior and posterior views

136

Skull and brain cast of Stegosaurus armatus, superior, inferior, and longitudinal views.
Portion of neck with anterior dermal plates of Stegosaurus stenops, superior view

136

10.
11.

Series of dermal plates of Stegosazirus stenops, side view
Dermal plate of Stegosaurus stenops, side and basal views
14. Dermal plate of Stegosaurus stenops. side and basal views
15. Tip of tail ^vitll spines of Stegosaurus stenops, lateral view
16. Tip of tail with spines of Stegosaurus (Diracodon) stenops, lateral view
17. Dermal spine of Stegosaurus stenops, lateral and anterior views
18. Dermal spine of Stegosaurus sulcatus anterior, lateral, and sectional views

136

136

12.

136

13.

^

19.

Skull of Stegosaurus stenops; sacral cavity of Stegosaurus, sp

136
.

'

136
136

13U
136
136
136

20. Coracoid, humerus, ulnae, and radii of Stegosaurus

136

21. Scapula, metacarpals, and hind foot of Stegosaurus

136

Skull of Eeloderma, and dermal ossicles of Stegosaurus stenops

136

Dermal plates of Stegosaurus stenops and 5. sulcatus, lateral vievr
24. Dermal plates of Stegosaurus stenops, lateral view
25. Fibula, ischium, and dermal tail spines of Stegosaurus
26. Scajjula, coracoid, and humerus of Hoplitosaurus marshi
27. Dermal ossifications of Hoplitosaurus marshi
28. Dermal plate of Iloplitosaurus rnarshi
29. Dermal plate of Hoplitosaurus marshi, lateral and posterior views
30. Dermal plate of Hoplitosaurus marshi, lateral and posterior views
31. Dermal bones of unidentified dinosaurs

136

22.

23.

136

136
136
136
136
136
136
136

32. Restorations of Stegosaurus ungulatus

136

33. Restorations of Stegosaurus ungulatus

136

34. Restorations of Stegosaurus ungulatus and 5. stenops

136

35. Restorations of Stegosaurus ungulatus and Stegosaurus

136

36. Restorations of Stegosaurus ungulatus.

37.

MuseumMap of " Quarry 13

Photograph of mounted skeleton in Peabody
136

'

136

'

TEXT FIGURES.
Tage.

Fig.

1.

Section of Quarry 13

3

4

2.

Map of Quarry 13

3.

Skull of Stegosaurus stenops Marsh, side view27

4.

Skull of Stegosaurus stenops"! Marsh, rear view28

5.

Stull of Stegosaurus stenops? Marsh, rear view

29.

ILLUSTEAITONS.

X

Page.

Pio.

6.
7.

Left quadrate and quadratojugal of Stegosaurus stenops f Marsh, lateral view
Left squamosal of Slegosawus stenops ? Marsh, ventral view

35
35
37

Right dentary of Stegosaurus ep. internal view
9. Thyrohyals of Stegosaurus sp
Ifl. Skull of Stegosaurus sp., oblique lateral view
11. Tooth of Stegosaurus ungulatus Marsh, outer, inner, and top views
8.

,

40

,

42

44

Dentition of right maxillary of Stegosaurus stenops Marsh, internal view
Atlas of Stegosaurus stenops ? Marsh, lateral, back, and front views
14. Axis of Stegosaurus sp. lateral view
15. Cervical vertebra of Stegosaurus ungulatus Marsh, side and front view
16. Articulated cer\dcal vertebrae of Stegosaurus stenops Marsh, ventral view

45
46

12.
13.

47

,

48

48

17. Posterior cervical vertebra of Stegosaurus ungulatus Marsh, side and front views
18.
19.

49

Anterior dorsal vertebra of Stegosaurus sp. side and front views
Anterior dorsal vertebra of Stegosaurus sp. side and fi'ont views

49side and front views

51

,

50

,

20. Posterior dorsal vertebra of Stegosaurus sp.

,

Dorsal vertebra of Stegosaurus ungulatus Marsh, side and front views
Sacrum and ilia of Stegosaurus ungulatus Marsh, ventral view
Pelvic region of Stegosaurus stenops Marsh, ventral view
Cast of nem-al cavity in sacrum of Stegosaurus ungulatus Marsh, side, top, and sectional

52

views
Second (?) caudal vertebra of Stegosaurus ungulatus Marsh, front view
26. Anterior caudal vertebra of Stegosaurus ungulatus Marsh, lateral view
27. Anterior caudal vertebra of Stegosaurus ungulatus Marsh, side and front views
28. Median caudal vertebra of Stegosaurus ungulatus Marsh, side and front views
29. Chevrons of Stegosaurus sp. side and posterior views
30. Chevron of Stegosaurus ungulatus Marsh, back and front views
31. Cervical rib of Stegosaurus stenops Marsh, internal view
32. Left sternal bone of Stegosaurus sp. superior and ventral views
33. Articulated sternal bones of Stegosaurus sp. superior view
34. Left sternal bone of Trachodon annectens Marsh, superior and ventral views
35. Left ulna of Stegosaurus ungulatus Marsh, side view
36. Carpus of Stegosaurus sp. front and superior views
37. Right fore foot of Stegosaurus sp. front and superior views
38. Right fore foot of Stegosaurus sulcatus Marsh, superior and front views
39. Outline of proximal ends of metatarsals of Stegosaurus sulcatus Marsh
40. Left fore foot of Stegosaurus stenops Marsh, palmar view
41. Unguals of Stegosaurus, top views'
42. Pelvis of Stegosaurus stenops Marsh, side view
43. Left pubis of Stegosaurus ungulatus Marsh, outer view
44. Right ischium of Stegosaurus ungulatus Marsh, internal view
45. Comparative views of Stegosaurus femora, front views
46. Left femur of Stegosaurus ungulatus Marsh, front views
47. Left tibia and fibula of Stegosaurus ungulatus Marsh, front view
48. Right tibia of Stegosaurus sp., distal view
49. Astragalus of Stegosaurus sp. proximal view
50. Calcaneum of Stegosaurus sp. lateral and front views
51. Metatarsal of Stegosaurus ungulatus Marsh, side and front views
52. Right hind foot of Stegosaurus sp. superior view
53. Vestigal metatarsal of Stegosaurus sp. side view
54. Ungual of Stegosaurus sp., front, side, and posterior views
55. Gular ossicle of Stegosaurus ungulatus Marsh, superior side and inferior views
56. Tubercular spine of Stegosaurus ungulatus Marsh, superior, inferior and end views
57. Nuchal plate of Stegosaurus sulcatus Marsh, side and posterior views
58. Diagram showing plates and caudal vertebrae of Stegosaurus stenops Marsh, as found

56

21.
22.
23.
24.

25.

,

,

,

,

,

^

-

54
55

58

58
59
60
62
63
63

65
66

66
69
70
71
73-

74

74
76

78
79
80
81
82

84
85

86

,

,

,

,

.-

in silm,

87
88
89
89
90

91
92
92
93

ILLUSTKATIONS.

XI
Page.

Fig. 59. Caudal spines of Stegosaurus ungulatus Marsh, side, front, basal, and sectional views

Caudal spines of four species of Stegosaurus, side views
61. Section of the neck of Stegosaurus
62. Section of the trunk of Stegosaurus
63. Section of the proximal part of the tail of Stegosaurus
60.

94
95

97
98
98

64. Section of the distal portion of the tail of Stegosaurus

99

65.

Dermal spines of Stegosaurus sulcalus Marsh, front view
Dermal spines of Stegosaurus longispinus Gilmore, side and back views
67. Caudal vertebrae of Stegosaurus longispinus Gilmore, side and end views
68. Right femur of Stegosaurus longispinus Gilmore, front view
69. Femur of Hoplitosaurus marshi (Lucas), front, back, and side views
70. Dermal scutes of Hoplitosaurus marshi (Lucas), top and cross-sectional views
71. Dermal plate of Hoplitosaurus marshi (Lucas), side and back views
72. Restoration of Polacanthus foxi Hulke, after Nopcsa
73. Dermal spine of a Ceratopsian ? dinosaur, side, front, and top views

110

66.

Ill

112
113
116

119

120
121

122

OSTEOLOGY OF THE AEMORED DINOSAURIA IN THE UNITED STATESNATIONAL MUSELTM, WITH SPECIAL REFERENCE TO THE GENUS
STEGOSAURUS.

By Charles Whitney Gilmore,
Assistant Curator of Fossil Reptiles, United States NationalMusmm.

INTRODUCTION.
In 1877 Prof. 0. C. Marsh described the first Stegosaurian fossils foundon thiscontment. In a series of short papers appearing at irregular intervals
up to theyear 1897, he presented the more important facts relating to the osteologicalstruc-

ture and the relationships of the genus Stegosaurus.

Of more recent years the principal contributions to our knowledge of thisdinosaur have been through the work of Dr. F. A. Lucas, directorof the American
Museum of Natural History, but formerly of the United States National Museum
and Prof. R. S. Lull, of Yale University.
In the present paper it is proposed to give for the first time a detailed
accountof the osteological structure of Stegosaurus, to be foUowedby systematic
descrip-

tions of aU the type-specimens of that genus and otherarmored dinosaur remains
contamed in the United States National Museum collections. With one exception the present work is based entirely upon National Museum
material, theexception being a specimen generously loaned me several years ago
by Mr. W. H.
Reed, of the University of Wyoming, and here described as the type of a new
species.
The collections in the United States National Museum were secured largely
through the United States Geological Survey, which financed the explorations
soenergetically carried on by field parties under the direction of the late Prof.
OthnielCharles Marsh.
The material at hand includes the remains of several individuals, each of which
represents a considerable part of the skeleton; also a vast number of separatebones.
Of the associated skeletons the type of Stegosaurus stenops Marsh is worthyofespecial mention, since it represents themost perfect specimen of the genus yet

discovered and the only one known that gives positive evidence as to thearrangement of the dermal armor. As contributing to our knowledge of the Stegosauria
it ranks with the mummified carcass of Tradhodon of
more recent discovery andexploitation.'

Wlien the Marsh collection was received at the National Museum in 1898 and 1899a very small part of the Stegosaurian material was in condition forstudy.
The
preparation of this material was begun
1906 and has continued, barring someinterruptions, up to the close of the year 1913.
All of the known Stegosaurusm1

H. F. Osbnrn, JTemoirs Amer. Mus. Nat. Hist., new ser., vol.

1, pt. 2, 1912, pp. 33-.54.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

2

specimens iii the collection have been prepared and are now available to the student

and for exhibition purposes.

The greater part of the early work in the preparation of these fossils was done
by Mr. N. H. Boss and myself, but that of later years has been carried on by Messrs.
N. H. Boss, C. V. Bressler, and G. B. Giles, and I can not too highly commend thedihgence, patience, and skill employed by them in extracting these fossils, often of
a deUcate nature, from a most refractory matrix.
Many of the wash drawings which are reproduced here through the courtesyof the United States Geological Survey were made by the late Mr. Frederick Berger
and were prepared under the direction of the late Prof. O. C. Marsh. The laterdrawings are nearly all the work of Mr. Rudolph Weber. The photographs weremade by Mr. T. W. Smillie, of the United States National Museum.

OCCURRENCE AND HISTORY.
The extensive collection of Stegosaurian remains in the National Museum has,with few exceptions, been obtained from two important, though widely separated,fossil deposits.
These are Quarry 13, located in Albany County, Wyoming, andQuarry No. 1, in Fremont County, Colorado. The former, I may say without fearof contradiction, was the source of the greatest accumulation of Stegosaurian
remains ever discovered, and from the latter has been obtained the wonderfullycomplete skeleton of Stegosaurus stenops (No. 4934, United States National Museum),in addition to many other valuable specimens.
-Although the history of these quarries has been given in previous articles, itis thought advisable to append a brief review of their discovery, location, and themethods employed in working them, in order to complete the present record.
HiSTOKY OF Quarry 13.

With the specimens upon which a portion of the present paper is based weremany of the original field labels, on which the locality is given as "Quarry No. 13,
8 miles east of Como, Wyoming."
Como was formerly a station on the Union
Pacific Railroad, situated at the foot of the historic Como Bluflf, but this section of

the track was abandoned in 1898, and the station has long since ceased to exist.

In response to an inquiry made of Mr. W. H. Reed, of Laramie, Wyoming (theoriginal discoverer), as to the history of the discovery of this deposit of fossils, hewrites:In August, 1879, I could see the end of Quarry No. 10, where the type of Brontosaurus excelsus
Marsh was found, so I took one of my men, Mr. E. (i. Ashley, and we started out east ft'om the main
bluff (or Como-bluff).
On the foiu-th day of our search, in the afternoon, being in the lowest of the Jurabone horizon, we found some hollow bones in the wash and soon after discovered the quarry. The firstbones to be taken up was a nearly comjilete skeleton of Allosaurus. After this skeleton had been taken
out, we found large quantities of Stegosaurus and Camptosaiirus boaes.
This quarry was entirely different from any other Jurassic quarry I have ever seen, the matrix being a fine quality of sand. * * *There were also numerous small tubes with an outer crust of calcite. These were nearly uniform insize and about one-half inch in diameter.
There were no large dinosam- bones found in this quarry,
but it seemed to be a favorite resort for the smaller species. * * * The quarry was cut through by
two gulches, and that portion on the west side of the west gulch was called 13 west, tliat part between
the gulches was 13 east, and that on the east side of the east gulch was 13J. This is as I started thework, and I believe Brown cootinued this plan. * * * i find in my old notebooks the original
locations that were filed in 1879 in order, to hold it fi-om trespassers.

OSTEOLOGY OF THE ARMOKED DINOSAURIA.

An inclosure in the above letter shows the quarry to have been located in thenortheast quarter of section 5, township 22 north, of range 76 west, Albany County,
Wyoming.
Under the supervision of Mr. Reed, at that time employed by Prof. O. C.
Marsh, Quarry No. 13 was worked for the remainder of the season of 1879 andduring the summers of 1880, 1881, and 1882. In 1883 further excavations weremade under the direction of Mr. J. L. Kenney, and in 1884, Mr. Fred Brown assumed charge of the explorations, which were continued uninterruptedly imtil theautunm of 1887, when the quarry was abandoned as exhausted.
The fossils in Quarry 13 were found in a stratum of sandy clay, as I have determined from the matrix still adhering to the bones, and as indicated in the section (fig. 1) made by Brown.
This layer is intercalated between bands of marlor clay, green below and brownish above, all three lying between layers of sandstone.
All are tilted at a considerable angle from the horizontal. The correlation of this layer with other fossil horizons in this region of Wyoming is discussed
in a previous article on the Osteology of Campto-

saurus, etc'—

Plan of tvork.
The fossils collect-

ed from QuarryNo. 13 prior to1882 are now preserved in the col^'°' 1~^'^<^^'°'* °^ quarry is.

lection of the Yalemade by Mk. Fred brown m 1884.

University Museum, while the specimens resulting from the later excavations (theexpense of collecting having been defrayed by the United States Geological

Survey) are in the paleontological collections of the United States National Museum.
Rough sketch maps of the quarry were made by Reed, on which he indicatedthe relative positions of all of the important bones found.

Unfortunately only a
Later Brown formulated a more detailed plan ofrecording the relative positions of the specimens uncovered.
The quarry was
divided (see fig. 2) into what he designated diagrams, beginning with No. 1 andending with No. 13. In some cases it is found that one diagram represented aseason's work, while in other instances several diagrams were worked out in one
year, probably due to the varying number of fossils found in the different sections.
The diagrams were subdivided into 2-foot squares and, the maps being platted on
the scale of 2 feet to the inch, bones as found could be accurately located on them.
Each bone or group of bones (when taken up in one block) was given a quarry
number, the bones found in each diagram beginning with number 1 (except
diagrams 2 and 3) and continuing serially for all of the specimens in that section.
The number being placed on a label with the specimens as well as on the map, theprecise position of a bone in relation to those found near it could be quickly andaccurately determined when the specimens reached the laboratory. A compilation

few of these are now available.

1

C. W. Gilmore, Proc. U. S. Nat. Mus., vol. 36, 1909, pp. 297-301.

BULLETIN

UNITED STATES NATIONAL MUSEUM.

diagrams was made in 1909 as shown in figure 2. A detailed map of"Quarry 13" with sketch drawings of the bones found in the different diagrams isshown in plate 37. There
was no datum whereby
diagrams 9 and 10 could
be accurately located andthe area worked by Reedof thesecan only be indicated in a
general way.
The list given below represents the fauna of thisquarry.

DiNOSAURIA.
ungula-*Stegosaurus
tus Marsh.

*S. sulcatus Marsh.
S. stenops Marsh.

*Diracodon

laticeps

Marsh = Stegosaurus stenops Marsh.
* Oamptosaurus dispar

Marsh.
*C. medius Marsh.
*0. nanus Marsh.
*C. hrowni Gilmore.
0. depressus Gilmore.

*Dryosaurus

altus

Marsh.

*Coelurus

fragilis

Marsh.
* Morosaurus lent us
Marsh.
Morosaurus sp.
Allosaurus sp.
Chelonia.
Glyptops

plicatulus(Cope).

Ceocodilia.
GoniopTiolis sp.

Pisces.

Not determinable.
[Those marked with an asterisk- (*) represent type-specimens.l

o o „
2

g^S

The list to follow is acomplete record of all thebones found in diagrams 1, 2, 3, 4, 5, 7, 8, 11, 12, and 13 of Quarry 13 between theyears 1883 and 1887, inclusive. By the aid of these lists with the map (pi. 37) the.

OSTEOLOUV OF THE AKMOJKKU DINOSAUBIA.
evidence for the association of the scattered parts of various individuals is graphArticulated and otherwise closely associated eleically portrayed to the reader.
ments, where there is reason for believing they j)crtain to one individual, are given
In some few instances quite widely separated bones
a single catalogue number.
have been thus catalogued on the evidence, as in the case of limb bones representing
opposite sides and of the same dimensions, same degree of rugoseness of the pointsof muscular insertion, and of the articular ends, etc.
This ])rocedure has in somecases probably resulted in a wrong association of parts, but the verification of these
determinations can now be readily made by any future student.
The following tables give the bones found in Quarry 13, and are arranged
according to the diagrams shown in fig. 2.
Fossil bones found in diagram 1, Quarry 13.

Original[uarryqua]

NoCat. No. 7360.

Cervical vertebra.

Do.

.do.

Fragment of dorsal vertebra.

Discarded.

Baso of dermal plat(>Cat. No. 7017.

Coraeoid,Cat. No. 7345.

rigiitIlium, rightCam-ptosauriis dispar.

Cat. No. 7631.

Fragment
Dorsal centrum
Fragment

Sauropod dinosaur..

Not catalogued.

Discarded.

Discarded.

Distal half of a rib

Not identified.

Fragments
Fragment

Discarded.

Do.
Do.
Do.

l-'ragment of rib.

Scapula, left

CawplosauruH dispar.. Cat. No. war,.

Fragment

Discarded.

J'roximal end of rib.

Cat. No. 7367.

Fragment

Discarded.

Do.

.do.

Stegosaurus . .

Cat. No. 7725.

Terminal phalanxCamptosauTus.

Cat. No. 6962.

Cervical rib

SkgosamuaCat. No. 7816.

Portion of atlas. .

Cat. No. 7707.

Process of dorsal vertebra.

Fragment

Discarded.

Proximal half of rib

Stegamurua.

Distal half of rib....doDorsal rib

Do.

Not identified.

Foot bono

PhalanxCat. No. 7728.

CaTTvptosaurus

Cat. No. 5962.

StcgomurusCat. No. 7728.

Caudal centrum

Sauropod dinosaur.

Not catalogued.

Cervical rib

Slegosaurm.

Cat. No. 7filO.

Fragment

Discarded.

Do.
Do.

6187.3°- Bull. 80-14-

.

.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Fossil bones found in diagram 1, Quarry 13—Continued.

Original

Name of bone.

quarryNos.

Name of animal.

Remarks.

Not found.

39

Do.

40
41

Do.

42

Cat. No. 7356.

43

do

Dorsal vertebra

Sauropod dinosaur

44

r.at. No. 7707.

Discarded.

Fossil bones found in diagram 2, Quarry 13.

Original

Name of bone.

quarryNos.

Name of animal.

Remarks.

4.1

Cat. No. 7814.

46

Cat. No. 7813.

Fossil bones found in diagram 3, Quarry IS.

Original

Name of bone.

quarryNos.

Name of animal.

Sauropod dinosaur.

Fragment
Tops of sacra! spines.

Not catalogued.

Fragment

Discarded.

Do.

Not found.
Discarded.

Not found.
Do.

Fragments

Discarded.

-do.

Do.

FragmentDo.

Not catalogued.

Caudal, transverse process

Fragment
Fragment of ilium
Sacral centrum

Do.
Do.

Camptosaurus.

C;it. No. 7815.

Fossil bones found in diagram 4, Quan-y 1-1.

Original

Name of bone.

quarryName of animal.

Remarks.

Nos.

Cat. No. 7735.

1

2

do

3

.

.do

Do.
Do.
Discarded.

4
5

do

Top of sacral spines

Cat. No. 7734.

OSTEOLOGY OF THE ABMOEED DINOSAUKIA.
Fossil bones found in 'diagTam 4, Quarry IS

Original
qjiarry— Continued.

Name of animal.

Name of bone.

Remarks.

Nos.

6

Camptosaurm

Cat. No. 7732.

7

Stegosaurus

Cat. No. 7791.

....doCat. No. 7734.

CamptosauTus

Cat. No. 5824.

....doCat. No. 7766.

8

Parts of sacral spines

Discarded.

9

10
11

Discarded.

12
13

do

14

do

Do.

...

Do.
Camptosaurus

15

Cat. No. 5823.

Discarded.

16
17

Camptosaurus

Cat. No. 5954.

18....doCat. No. 7766.

19....doDo.
Discarded.

20

Do.

21

Do.

do

22
23

Stegosaurus

Cat. No. 7823.

Morosaurus

Cat. No. 7817.

23

do

do

Do.

26

do

.do

Do.

24

27
28

.do

29

do

30

do
do

31

32

.

.

--

.

.do

.

do

33

...do

Do.

do

Do.

do

Do.

.do

Do.

do
do

Do.
Do.
Do.

.do

Do.

...do

34

Cat. No. 7711.

Stegosaurus

35
36Discarded.

37

Do.
Do.

38
39

...do

40

do

Do.
.

Do.

..

Do.

41

42

Cat. No. 7817.

Morosaurus

IIium,left

Discarded.

43

Do.

do

44
45

46

do

47
48

.

.

Morosaurus

Cat. No. 7817.

do

Do.

.do

Do.

...do

Do.

49

do

do

Do.

50

do

.do

Do.

51

...do

33

do
do
do

.do

Do.

54

...do

...do

Do.

32

35

56

.

57

.

Do.
.

...

Do.

do

do

Do.

.do

...do

Do.

do

do

Do.

.do

Do.

...do

Do,

do

58
39

do

.do

.

'

BULLETIN" 89, UNITED STATES NATIONAL MUSEUM.
Fossil hones found in diagram, 4, Quarry IS— Continued.

Original

Name of boue.

quarryNos.

Name of animal.

MoTosauTUs

60
i

do

61

62

Remarks.

Cat. No. 7817.

.do

Do.

Slegosamus

Not catalogued.

Not found.

63

Stegosaurus ungu-

64Cat. No. 6039.

lalus.

65

do

do

Do.

66

do
do

.do

Do.

do

Do.

63

do

do

Do.

70

do

.do

Do.

71

do
do

.do

Do.

do.

Do.

do
do

do

Do.

74

do..

Do.

75

do

do

Do.

76

do

.do

Do.

77

do

.do

67

do...

68

72
73

78

do

79

do

80

do
do

SI

Do.

do
;

Do.

Do.

do.

.

do.

.

.do

Do.

Do.

Do.

83

do
do

84

do

.do..

85

do

.do...

Do.

83

do

.do

Do.

87

do

....do

Do.

82

.do

Do.

do

Do.

do

83

Do.

Do.
Discarded.

83

Stegosaurus ungur

90

Cat. No. 6099.

lotus.

do

91

92

do
Stegosaurus f

93

Do.
Cat. No. 7822.

Camptosaurus

Cat. No. 7818.

Stegosaurus

Cat. No. 7735.

Discarded.

94
95

96

do

.do

Do.

97

do
do

do
do

Do.

98
99

do
do

.do

100

do

Do.

101

do

do

Do.

do

Cat. No. 7822.

102

do

Do.

Not identified

105

do

106
...

.do.

..

.do

do

110

Cat, No. 7796.

Do.

Do.
Discarded.

108
109

Do.

Discarded.

103

104

107

Do.

Dermal ossicles

Stegosaurus

Cat. No. 7947-.

Not identified

Cat. No. 7798.

1

-

-- ,

.

OSTEOLOGY OF THE AKMOKED DINOSAUEIA.
Fossil bones found in diagram 4, Quarry IS

Orifrinal

Name of bone.

quarryNo?.

Caudal centrum—Continued.

Name of animal.

Not identified.

.

Fragment

Cat. No. 7790.

Discarded.

Do.
Cervical vertebra

Cat. No. 7353.

.

-do-

Do.

Fragment

Discarded.

Basal part of skull and otherfragments.

Cat.No..'i997.

Fragment

Discarded.

Top of dorsal spine

Do.
Do.

Fragment
Caudal centrum (anterior;Cat. No. 7765.

Fragment of dorsal rib

Discarded.

Cervical vertebra

Stcgosaurus ungu-

Dorsal vertebra (anterior)CamptoswuTus

Cat. No. 7348.

latus.

Cat. No. 7727.

Discarded.

Fragment

Do.

Caudal centrum
l28

Stcgosaurus.

Cat. No. 7358.

Top of caudal spiue.

Not

Fragment
Fragment of skull

Discarded.

Sacral rib

Cat. No. 73.)6.

cata-logued.

Not

cata-

logued.

Do.

3 sacral centra

Caudal spine, anterior-

Not

Process to dorsal.

Cat. No. 7716.

"Rib portion

Not

cata-

cata-

logued.

Fnigment of rib
Fragment
Metatarsals 11, III-

Discarded.

Do.
Camptosaurus na-

Cat. No. 5960;

on mounted
skeleton.

Fragmeut of dermal plate
Femur, riglit

Cat. No. 7011.

rrocess to dorsal vertebra

Cat. No. 7710.

Portion of cervical rib

NotDiscarded.

cata-logued.
Cat. No. 6001;

Cervical vertebra -on mounted
skeletonofC. browni.

Cervical process

Stcgosaurus.

Cat. No. 7731.

Portion of dorsal rib

Fragment

Top dorsal spine

Cat. No. 735'1.

Discarded.

Stcgosaurus

Not

cata-

logued.
Cat. No. 7787.

Sacral rib

Eadius, left

Stcgosaurus stenops Cat. No. 4929.

Do.

Ulna, loft

Fragment
Cervical centrum

Discarded.
Stcgosaurus.

Cat. No. 7639.

.

10

....

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

—Continued.

Fossil bones found in diagram 4, Quarry IS

Original

Name of bone.

quarryName of animal.

Kemarks.

Fragment of rib.
FragmentDo.

-do.

Proximal half of rib, left

StegosauTus.

Cat. No. 7731.

Fragment ol rib

Do.

Portion of thoracic rib

Do.

Fragment of dermal plate

Discarded.

Portion of dorsal rib

Cat. No. 7731.

Cervical centrum

Cat. No. 7639.

Posterior cervical rib

Cat. No. 7780.

Fragment

Discarded.

l^ortion of cervical I'ib

Cat. No. 77X8.

Fragment

Discarded.
Do.

-do.
Cervical vertebra

Cat. No. 7355.

Caudal centrum (anterior)Cat. No. 7638.

Scapula, left

Cat. No. 7374.

Portion of dorsal process. .

Not

Proximal half of rib, left

Cat. No. 7731.

cata-

Portion of dorsal rib

Do.

Fragment

Discarded.

Portion of dorsal rib

Cat. No. 7731.
Cat. No. 7731.

.do.

Fragment.

Discarded.

Do.

.do.
Basioccipital portion of the skull.

Cat. No. 5990.

Fragment of rib

Discarded.

Skull No. 4

Cat. No. 4935.

;

Fragment

Discarded.

Do.

-do.

Humerus, left

Cat. No. 4929.

Do.

Scapula, leftAnterior dermal plate.

Cat. No. 7015.

Fragment of plate

Do.

Metacarpal

Cat. No. 7418.

Intermedium

Cat. No. 7580.

Carpal bone

Do.
Do.

.do.

Dermal spine
Caudal centrum
Fragment
Dorsal centrum
Cervical centrum
Dermal plate
Dermal plate, neck
Fragment
Ischium, left

Cat. No. 7359.
,,

Discarded.
Cat. No. 7648.
Cat. No. 7790.
Cat. No. 7615.

Do.
Discarded.
,

Cat. No. 2111.
Cat. No. 7365.

Metatarsal IV, right
5 bones, left fore footCat. No. 7647.

,

Cat. No. 4929.

Dermal scutesCat. No. 7615.

Process of cervical vertebra.

Cat. No. 7640.

Portion of rib

Not

cata-'

.

-

.

.

OSTEOLOGY OF THE ARMOKED DINOSAUKIA.
Fossil bones found in diagram 4, Quarry 13

11—Continued.

Original

Name of animal.

Name of bone.

quarryNos.

Remarks.

Discarded.

205

do

do

Do.

207

-do

Cat. No. 7584.

208

.do

Do.

209

do

206

210

.do

211

do

Do.
Do.

do
.

.

.

.do

Do.

-

Do.

do

212

Not

213

cata-

logued.
Cat. No. 7418.

214
215

Discarded.

216

Cat. No. 7380.

Fossil bones found in diagram 5, Quarry 13.

OriEinal

Name of bone.

quarryName of animal.

Dorsal centrum

Cat. No. 7807.

Metatarsal III, left

Cat. No. 7365.

Sacral rib (?)...

Cat. No. 7816,

Piece of rib

Discarded.

Cat. No. 7364.

Fragment
Caudal centrum.

Do.
StegosauTus stenops.

.

Fragment
Dermal plate.do.

Cat. No. 6135.

Discarded.
Cat. No. 7584.

SUgosaurus stenops.

Cat.No.4714.

Do.

.do.

Cat. No. 7380.

Femur, rightCat. No. 4714.

Caudal vertebra.

Ungual phalamx.

Stegosaurus

Cat. No. 7369.

Caudal vertebra..

Stegosaurus stenops.

Cat. No. 6135.

Do.

.do.

Cat. No. 7371,

Left scapula and caudal (Cat. No.

may be op-6135).

positetoNo. 7362.
Caudal vertebra.

Stegosaurus stenops.

Cat. No. 6135.

Do.
Do.
Do.

ChevronCat. No. 4714.

Sacral rib

Cat. No. 7799.
Cat. No. 7363.

ChevronCat. No. 7584.

Dermal plate.
Cervical rib . -Camptosaurus hrowni.

Cat. No. 4282.

Fibula, right..

Cat. No. 7380.

Dermal plate..

Cat. No. 7584.

Pubis, left

Cat. No. 7771.

.

12

.
.

BULLETIN 89, UKITED STATES NATIONAL MUSEUM.
Fossil bones found in diq,gram5, Quarry IS

Original
cniarry—Continued.

Name of animal.

Femur, left
Dermal spine

Stegosaurus
Stegosaurus

doCat. No. 7370.
Cat. No. 6135;
pair.

Cat. No. 6135.

Caudal vertebra.
do

Do.

.do.

Do.

Caudal vertebra and chevron.

Caudal vertebra

Caudal vertebra and chevron.

Caudal vertebra

Caudal vertebra and chevron.

Do.

Caudal vertebra

Do.

Caudal vertebra and chevron

Do.

Calcaneum, left

Cat. No. 7367.

Caudal vertebra

Not

cata-

logued.

Dermal plate of tail

StegosaurtLS stenop^

Cat. No. 6135.

Foot bene

SiegosauTUS

Cat. No. 7380.

Tibia and astragalus, rightDo.

Dermal plate

Stegosaurus

Cat. No. 4714.

3 digits of right hind foot, and skull.

Stegosaurus

Cat. Nos. 4280

Dermal plate

Stegosaurus stenops.

Cat. No. 4714.

Tibia (young).

Stegosaurus

Cat. No. 7373.

Dorsal rib

Camptosaurus browni.

Cat. No. 4282.

and 2274.
Do.

..

—
..

)

.

OSTEOLOGY OF THE ARMOEED DINOSAUEIA.
Fossil bones found in diagram 5., Quamj 13

13— Continued.

Original

Name of bone.

quarryNot cata-

Chevron..

logued.

Dorsal rib (oth of right side)

Camptosaurus broivn

Cat. No. 4282.

StegosauTus stevop^

Cat. No. 6135.

Do.

Humerus, left

Do.

Radius, ulna, and manus, left.

Caudal and chevron

Do.

Caudal vertebra

Caudal spines

Chevron....doDo.
Do.

Caudal centru

StegosauTus .

Cat. No. 7S87.

Not cata-

Top of spine.

logued.
Cat. No. 7361.

capula and coracoid, rightNot cata-

Process to caudal

logued.

Spinous process

Camptosaurus brown

Cat. No. 4282.

Sternal bone

StegosauTus

Cat. No. 7618.

Fragment

Discarded.

Dorsal, seventhCat. No. 4282.

Dorsal, sixth

Do.

Dorsal, fifthDo.

Dorsal, fourthDo.

Dorsal, third

Dorsal, second

Thoracic rib (eighth of right side

Head of dorsal rib

Do.

Caudal transverse

Not catalogued.

Piece of dorsal rib

Camptosaurus browni.

Top of spinous process

CamptoCat. No. 4282.

Discarded.

Do.

Fragment

Cat. No. 7684.

Portion of dermal plate

Cat. No. 4282.

Portion of right ischiumCamptosaurus browni.

Fragment of spinous process

Camptosaurus ?

Discarded.

lochium, lcf(

Camptosaurus browvi.

Cat. No. 4282.

Do.

Dorsal rib (head)
Posttrontal

Cat. No. 7421.

Top of spine

Not catalogued.

Cervical rib

Camptosaurus browni.

Cat. No. 4282.

Dorsal, eighthDo.

Dorsal, ninth

Do.

Dorsal, tenthDo.

Dorsal, eleventhDo.

Dorsal, twelfth

Do.

Dorsal, thirteenth . .

Do.

Dorsal, fourteenth . .

Do.

Dorsal, fifteenth

Dorsal, sixteenth
Sacral vertebra, first

.

14

,.
.

.

.
.

.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

—Continued.

Fossil hones found in diagram 5, Quarry 13

Original

Name of bone.

quarrySacral vertebra, second

Name of animal.

Camptosaurus browniCat. No. 4282.

do

Sacral vertebra, third
Sacral vertebra, fourth .
Sacral vertebra, flfth

Caudal vertebra, first
Caudal vertebra, second.
Caudal vertebra, thirdDo.

.

Cat. No. 7362.

Coracoid, right

Supraorbital

Camptosaurus

Cat. No. 7632.

Dermal plate

Stegosaurus

Cat. No. 7584.

Ilium, leftCamptosaurus browni.

Cat. No. 4282.

Fragment

Discarded.

Caudal centrum

Cat. No. 4714.

Caudal and chevronCat. No. 6136.

do

Do.

Caudal vertebra

Do.

Caudal and chevron

Do.

Caudal vertebra.
....doCat. No. 6136.
,-do.

Portion of dorsal rib

Camptosaurus browni.

Caudal, sixth

Cat. No. 4282.

Do.

Caudal, fifthDo.
Cat. No. 7372;

Ilium, leftmaybeopp.
239 dgm .7.

Spine fragment

R ib fragment

Discarded.

Do.

,

Fragment
Fragment of plate.

Do.

Do.

Pubis

Not found.

Scapula, rightCat. No. 7362,

coracoid 139

same indiv.
Ilium, rightCamptosaurus browni.

Caudal, third

Cat. No. 4282.

Do.

Caudal, fourth...

Do.

Caudal, seventh.

Do.

Caudal, eighth...

Do.

Caudal, ninth

Do.

Caudal, tenthDo.

Caudal, eleventh

Caudal vertebra..
.do.

Dermal plate.
ChevronCat. No. 4714.

Camptosaurus browni.

Cat. No. 4282.

.

.

.

OSTEOLOGY OF THE AKMOEED DINOSAUKIA.

15

Fossil bones found in diagram 7, Quarry IS.

Original

Name of bone.

quarryNos.

Name of animal.

Calcaneuni,left..

Cat. No. 7398.

PhalanxCat. No. 7400.

Discarded.

Spinous process.

Camptosaurus (?).

Metacarpal

Cat. No. 7785.

Discarded.

Fragment
Ungual phalanx..
Phalanx

Stegosaurus

Cat. No. 7401.

Do.

Fragment

Discarded.

Metacarpal

Cat. No. 7401.

Fragment

Discarded.

Do.
Do.
.do..

Do.

Ilium, rightCat. No. 7385.

Femur, rightDo.

Radius, rightCat. No. 7401.

Scapula, left

Cat. No. 7371.

Fragment

Discarded.

Metacarpal V, right. .

Cat. No. 7401.

Do.

Foot bones, right fore fDo.

Ulna, rightLarge dermal plate

Caudal vertebra....doCat. No. 7585.

Dhacodon laiiceps.

Cat. No. 4288.

Do.
Do.
Clavicle (?)

Cat. No. 7382.

,

Discarded.

Process to vertebra..

Dermal plate
Rib

Cat. No. 4714.
(?)

Not

c a t a-logued.

Scapula,left

Coracoid,

leftCamptosaurus browni.

Premaxillary, right.

Cat. No. 4282.

Do.
Cat. No. 738:3.

Small dermal plate.

MoTOsaurus (?)..

Cat. No. 7759.

Rib, fragment

Not cata-

Ungual phalanx..
PhalanxCat. No. 7401.

logued.

Do.
Do.

..

16

.

...

.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Fossil hones found in diagram 7, Quarry 13—Continued.

Original

Name of bone.

quarryNos.

Name of animaCat. No. 7401.

StegosauTUs

Not found.
Cervical vertebra..

Stcqosaurus

Spinous process

Diracodon laticeps.

.

.

Dermal plate

Cat. No. 7402.
,

StegosauTUs

Cat.No.4288(?)
Cat. No. 758o.

Diracodon laticeps..

Cat. No. 42SS.

Diracodon laticeps.

Cat. No. 4288.

Fragment of rib

Discarded.

Caudal vertebra.

Do.
Do.
Do.

Do.
Do.

Not catalogued.

Camptosauriis nanus

Metatarsal IV, left.

Fragment of rib.

Cat. No. 7394.

Not.

c at a-logued.

Not found.
Ulna, rightCat. No. 7754.

Pubis, portion of left.

Cat. No. 7755.

Ungual phalanx
Metacarpal V, left

Cat. No. 7736.
Cat. No. 77S3.

Discarded.

Piece of rib

Top of caudal spine

Nof cata-.

logued.

Camptosaurus bro

First dorsal
Cervical, ninth with 1 rib

Cat. No. 4282.

Do.

Cervical, eighth with both ribs.

Do.

Fragment of dorsal spine

Discarded.

night dentaryCat. No. 4282.

Kib, fragment

Discarded.

.do-.

Cervical, seventh..

Camptosaurus hrowni.

Humerus, right ..

Not cata-

nib, fragment

logued.
Cervical vertebra

Cat. No. 7812.

.

Cervical vertebra, .

Caudal vertebra.

.

Diracodon laticeps .

-do..

Cervical rib

Cat. No. 7946.

Transverse process

Cat. No. 7808.

Fragment of rib
Fragment
Fragment of vertebra
Vertebra (young dorsal centrum)
Dorsal centrum
Fragment

Discarded.

Cora^oid, right

Caudal centrum

Fragment of vertebra
Scapula, right

Do.

Do.
Cat. No. 7393.

Cat. No. 7810.

Discarded.

Camptosaurus hrowni..

Cat. No. 4282.
Cat. No. 7781.

Discarded.

Camptosaurus brozcni.. Cat. No. 4282.

.

.

17

OSTEOLOGY OF THE ARMORED DINOSAURIA.
Fossil bones foundin diagram 7, Quamj 13

Original

Name of bone.

quarryNos.

—Continued.

Name of animal.

No t oata-

Eib, proximal portic

Discarded.

Kib, fragment

Fragment ofslaill
Ungual phalanxCamptosaurus.

Cat. No. 7421.

StegosauTus

Cat. No. 77S2.

Process of caudal vertebra

Not c a t a -"Ungual phalanx...

Cat. No. 7782.

Fragment of spine.

Not cata-

logued.

logued.

Camplosaurus browni.

Cervical, fourthCat. No. 4282.

Discarded.

Fragment of vertebra.

Do.

Do.
Do.

Fragment
Metacarpal V, right.

Cat. No. 7399.

Ungual phalanx
Hyoid
Fragment

Cat. No. 7:J66.

.do..

Radius and ulna, rightCat. No. 7377.

Discarded.

—Do.
Camptosaurus bTowm.

Cat. No. 4282.

Do.

Manus, right
Fragment of vertebra

Discarded.

Caudal vertebra, anterior.

Cat. No. 7388.

Fragraenl

Discarded.

.Sternal boneCat. No. 7619.

Discarded.

Fragment

Not found.
Caudal ceutrnm.

No t cat a-

Fragment

Discarded.

Caudal centrum, anterior..

Cat. No. 7634.

Ungual phalanxCat. No. 7399.

Top of caudal spine

Not

logued.

c a t a-logued.

Do.

Transverse process of caudal..
Sacral rib

Cat. No. 7786.

Caudal spine

Not

Fragment
Fragment of vertebra..

Discarded.

o a ta-logued.

Do.

Do.

.do..

Cat. No. 7632.

Supraorbital, right

Fragment of vertebra.

Discarded.

Tibia, rightCat. No. 7387.

Do.

Astragalus

Caudal vertebra

Siegosaurus stenops

Cat. No. 6135.

Piece of rib(?)

Not catalogued.

Piece of rib

Discardeil.

Ungual phalanx.
Fragment

Cat. No. 7784.

Discarded.

Do.

.

18

.

.

.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

—Continued.

Fossil bones found in diagram 7, Quarry IS

Original

Name of bone.

quarryNos.

Name of animal.

Cat. No. 7417.

Metacarpal.

Fragment..

Discarded.

Rib

Not catalogued.

Caudal vertebra.

Stegosaurus stenopfi.

Cat. No. 4714.

Do.
Do.
Do.
Do.

.do..

Cat. No. 7403.

Cat. No. 7620.

Sternal bone

Spinous process, caudal.

Stegosaurus stenops.

Cat. No. 4714.

Do.

Dermal spine
Fragment of rib

Not cata-

Fibula, left

Cat. No. 7389.

Fragment

Discarded.

logued.

Caudal vertebra

CamptosauTUS.

Cat. No. 7082.

First phalanx, digit I, manus.

Cat. No. 7633.

Fragment

Discarded.

3 carpal bones, left foot. .

Cat. No. 7403.

Ungual, phalanxCat. No. 7419.

Caudal vertebra, process.

Cat. No. 7798.

Astragalus

Cat. No. 7636.

Dorsal centrum

Cat. No. 7802.

Fragment

Discarded.

.do..

Do.

Do.

Do.

Do.

Fragment of rib
Stegosaurus

Cat. No. 7420.

Ungual, digit TV, right hind footCamptosaurus browni.

Cat. No. 4282.

Pubis, right

Stegosaurus

Cat. No. 7420.

Pubis, left

Cat. No. 7397.

Calcaneum, right

Fragment
Phalanx
Ischium, rightIschium, left
Metatarsal I, left footDiscarded.
Stegosaurus..

Cat. No. 7419.
Cat. No. 7610.

Do.
Cat. No. 7415.

Metatarsal III, left footPhalanx, digit III
Metatarsal II, left

Phalanx II
Ungual phalanx

Do.

Metatarsal IV

Do.

Phalanx

Do.

do

Do.

CoracoidCat. No. 7797.

Fibula, left

Cat. No. 7390;

may be opposite

of

200.

Caudal centrum.

Cat. No. 7649.

.

—

.

.

OSTEOLOGY OF THE AKMOEED DINOSAURIA.
Fossil hones found in diagram 7, Quarry 13

19—Continued.

Original

Name of animal.

Name of bone.

quarryNos.

Spine of caudal, . .

Cat. No. 7649.

Coracoid, left

Cat. No. 2112.

Fragment of skull.

Not catalogued.

Do.

Proximal ecd of rib

Cat. No. 7384.

Fibula, right

Fragment limb bone
Ulna

Discarded.

. .

I..,
Stegosaurus stenops.

,

Head of rib
Dorsal vertebra(?)

Cat. No. 4929.
Cat. No. 7809.
Cat. No. 7789.

,

Fragment of spine

Discarded.

Metatarsal III, right.

Cat. No. 7416.

Not cata-

Spine to vertebra

logued.

CamptiCaudals, thirteen to sixteen.

Part of sacrum

Cat. No. 4282.
Cat. No. 7809.

Part of vertebra

Cat. No. 7386.

,

Caudal vertebra

Camptosaurus.

Cat. No. 7082.

Humerus, right

Sttgosaurus

Cat. No. 4929.

Sacral rib

Stegosaurus

Cat. No. 7386.
Cat. No. 7764.

Metacarpal

Fragment

Discarded.

Not found.
Dorsal centrum

Stegosaurus

Cat. No. 7386.

Caudal, twenty-firstCamptosaurus browni.

Cat. No. 4282.

Caudal, twenty-second

Do.

Caudal, twenty-thirdDo.

Caudal, twenty-fourth
Caudal, twenty-fifth

Caudal, twenty-sixth
Caudal, twenty-seventh

Caudal, twenty-eighth
Caudal, twenty-ninth
Caudal, thirtiethCaudal, thirty-first

Caudal, thirty-second
Caudal, thirty-third
Caudal, thirty-fourth

Caudal, thirty-fifth
Caudal, thirty-sixth

Caudal, thirty-seventh
Caudal, thirty-eighth

Fragment of spine

Discarded.

Transverse process to caudal

Not catalogued.

do

,

Do.

Iliiun, rightCat. No. 7392.

Dorsal centrum

Cat. No. 7705.

Cervical centrum

Cat. No. T708.

.

.

20

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Fossil hones found in diagram. 8, Quarry 13.

Original
cniarry

Name oi bone.

Name of animal

Not

Fragment of rib.

cata-logued.

Caudal centrum (anterior)Cat. No. 73S1.

.

Tibia, left

Cat. No. 7379.

Transverse process (caudal).

Cat. No. 7381.

Dermal spine

Cat. No. 7375.

Process (dorsal vertebra)

Cat. No. 7705.

Astragalus

Cat. No. 7378.

Portion of dermal plate

Not cata-

Fragment
Dorsal centrum.
Fragment

Cat. No. 7381
Cat. No. 7705.

Sacral centrum..

Cat. No. 7381.

logued.

Discarded.

.do.

Do.

Caudal process...

Cat. No. 77(i3.

Caudal centrum.

Do.

Radius, rigbt

StcgosauTus stenops

Cat. No. 4929.

ChevronCat. No. 7376.

Sacral rib

Cat. No. 7381.

Fossil bo?ies found in diagram 11, Quarry IS.

Originalqu.arry

Name of bone.

Name of animal.

Remarks.

Nos.

1

Cervical vertebra

Cat. No. 7405.
Cat. No. 7411.

23

Pieces of ribs

4

Portions of ilium

do

Do.

Part of rib

do.

Cat. No. 6531.

6

Pubis, portion of right7

Cervical vertebra

8

Caudal vertebra

9

do

10

do..

U
12

.do..

.

Cat. No. 7609.
.

.

.

do
Spine to caudal vertebra

13

14

.

15
16

Rib, thoracic

17
IS

do

19

do

20

do

21

Discarded.

.

.

.do

Cat. No. 7404.

doCat. No. 6629.

do.

Do.

do

Do.

do
do

Do.

do.

Cat. No. 6531.

Do.

Discarded.

.do

do

Do.

do

Cat. No. 7411.

.doCat. No. 6531.

do

--..

Cat. No. 6629.

Do.

do

Do.

do

Do.

22

do
do

23

do

24

do

do
do

25

do

Do,

Do
Do
Do.

OSTEOLOGY OF THE AEMOKED DINOSAUKIA.
Fossil bones found in diagram 11, Quarry 13
OridnalquarryNos.

Name of bone.

—Continued.

Name of animal.

26

21

Steffosaurus

Remarks.

Cat. No. 6629.

27

do

do

Do.

28

do

Cat. No. 6531.

do.

Do.

do

Do.

33

do
do
do
do
do
do

do
do

Do.

34

do

do.

Do.

35

do
do

do

Do.

do
do

Do.

do

Do.

29
30
31

32

36

40

do
do
do
do

41

do

42

do

37
as

39

Do.

Do.
..

Do.
Do.
Do.
Do.

43

...do.-

44
45

Caudal vertebra

46

doDermal plate (tail)

47

Do.

Do.

do
do
do
do

Discarded.
Cat. No. 6631.

Do.
Do.

Fossil bones found in diagram 12, Quarry IS.
Original

Name of bone.

quarryNos.

1Name of animal.

Fragment, spinous process2

Remarks.

Stegosaunis

Discarded.

StegosoAiTus ungu-

No. 6646.

latus.

3

Part of radius

do

No.

Cat.

6646;

Nos. 3 and 5 belong together.
4

Femur, right

.

.

.do.

Cat. No. 6646.

5

do

Do.

6

do.

Do.

7

...

8
9

Tibia, calcaneum, and astragalus,
right.

.do..

Do.

Stejosaurus

Discarded.

StegosauTUs ufigu-Cat.

latus.

'

No.

6646;

coOssifled withastragalus.
10

Carpal bone (ulnar complex)do11Cat. No. 6646.

Discarded.

12

Stegosaurus ungvr

Cat. No. 6646.

latus.

13

.

14
15

10
17

.do..

Do.

do

Do.

do

Humerus, right

Do.
do..

Do.

do

Do.

18

Discarded.

19

Stegosaurus ungu-

Cat. No. 6646.

latus.

20
21

Fragment

Discarded.
Stegosaurus ungulatus.

51873°—Bull.

,

22

.

,

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Fossil bones found in diagram 12, Quarry IS— Continued.

Original

Name of bone.

quarryFragment
Fragments
Chevron (anterior).

Name of animal.

Stegosaurus ungu-

Cat. No. 6646.

latus.

Top of caudal spine
Fragment of plate
Caudal vertebra (anterior)

Do.
Discarded.
Stegosaurus ungu-

Cat. No. 6646.

latus.

Piece of rib

Dermal spine (tail)Fragment of dorsal process
Part of neural process, dorsal.

Fossil bones found in diagram 13, Quarry 13.

Original

Name of bone.

quarryName of animal.

Nos.

Head of rib

Cat. No. 6531.

Scapula, rightCat. No. 7411.

Parts of skullandatlas, articulatedCat. No. 6645.

Cervical vertebra

Cat. No. 7412.

Dermal spine
Cervical centrum
Parts of skull

Cat. No. 7413.
Cat. No. 7412.

Stegosaurus

sten-Cat. No. 6645.

ops.

Not catalogued.

Spine of caudal vertebra.

Cat. No 7413.

Dermal spine
Dermal plate
Dermal spine

Stegosaurus

Chevron

Stegosaurus

Caudal vertebra.
.do.

Dermal spine
doDermal spine (?).

Not catalogued.
sten-

.

Cat. No. 6629.

Cat. No 6531.

Do.
Do.
Do.

Do.
Do.

do

Do.

.do.

Cat. No. 7413.

Dermal plate
ChevronCat. No. 6531.

Coracoid, rightCat. No. 7411.

Rib

Do.

Do.

Spinous process, caudal.

Not catalogued.

Rib, thoracic

Cat. No. 7411.

Dorsal vertebraDo.

Not found.
Caudal vertebra.

Cat. No. 6629.

.
.

.

.

OSTEOLOGY OF THE ABMOBED DINOSAURIA.
Fossil bones found in diagram 13, Quarry IS—Continued.

Original

Name of bone.

quarryNos.

Caudal vertebra.

Name of animal.

Stegosaurus

sten-Cat. No. 6fi29.

ops.

Do.

Do.
Do.

Dorsal vertebra

Do.

—

Cat. No. 7411.

Fragment
Rib

Discarded.
Cat. No. 6531.

Fragjpent nf plate.

Discarded.

Dermal plate

Cat. No. 6.531.

Do.

.do.
Caudal vertebra

Cat. No. 7410 (7).

Part of rib

Cat. No. 6531.

Pubis, left

Do.

Centrum of dorsal vertebra.

Do.

Ischium

Do.

Part of rib

Do.

Dermal plate

Do.
Cat. No. 6531 (?).

Ischium

Fragment of plate
Fragment(?)

I'art of ischium

StegosauTus..

Discarded.

Do.
Cat. No. 6531.

Fragment of rib

Not catalogued.

Dorsal vertebra

Cat. No. 6531.

do

Do.

Dorsal vertebra and riliDo.

Fragment of spine

Discarded.

Part of rib

Cat. No. 6531.

Not found.
Cat. No. 6531.

Dorsal vertebra

Do.

Do.

Not found.
Do.

Fragment

Discarded.

Dorsal vertebra

Cat. No. 6531.

Do.
Do.

Do.

Do.
Do.

Not found.
Fragment of rib
Sacrum and ilium.

Discarded.
Cat. No. 6531.

Not found.
Cat. No. 6531.

Fragments dorsal vertebra

Dermal plate
Rib
ChevronCaudal vertebra

Humerus, right
Fragment sternal boneCat. No. 6531 (?).

CamptosauTus

Cat. No. 7406.

Stegosaurus

Cat. No. 7410.

—

Do.
Cat. No. 7409.
Cat. No. 6531.

23

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

24'

Fossil bones found in diagram 13, Quarry 13—Continued.

Original

Name of bone.

quarryNos.

Fragment
Dermal plate
Dermal plate

Name of animal.

Stegosaurus .

Discarded.
Cat. No. 6531.

Do.

Cervical vertebra.

Not catalogued.

Fragments

Discarded.

CbevronCat. No. 7410.

Pubis, right...

Cat. No. 6646.

Fragment

Discarded.

Do.
Do.

Do.

...:.doDorsal centra.

Cat. No. 6531.

Not found.
Cat. No. 6646.

Pubis, part
Pubis, left

Do.

Pubis, partCat. No. 7608.

Fragment

Discarded.

Che\TonCat. No. 7407.

Ungual phalanxCat. No. 7408.

Pubis, partCat. No. 6646.

"Right fibula, proximal half.

•

Do.

Fragment of rib
Median caudal vertebra

Cat. No. 7410.

Pubis, rightCat. No. 6531.

Discarded.

History op Qcarby No. 1.'

This quarry was situated on the west side of jOii Creek (Four Mile Creek) at theentraace to Garden Park, Fremont County, some 9 or 10 miles east by noith ofCanon City, Colorado (pi. 1). A map ol this region, drawn by Mr. M. P. Felch,shows it to have been located in the northeast quarter ot the southeast quarter ofsection 28, township 17 north, range 70 west.
Fossil bones werefixst discovered in thislocahty in 1876 by the family of Mr.

Through the CanonCity and Denvernewspapers the matter was brought
and in the spring of 1877 Dr. S. W. Wilhston
was sent to Canon City to investigate the alleged discoveries. The quarry, opened
by Doctor WiUiston, was worked for several years for Professor Marsh under thevery careful and skillful supervision of Mr. Felch. In the autumn of 1886 ^this quarry was abandoned and nothing further was done here in the way of collecting until 1900, when, under the direction of the late Mr. J. B. Hatcher, Mr. W. H.
Utterback reopened the quairy (see upper figure, pi. 1) foi the Carnegie Museum, ofPittsburgh, Pennsylvania, and worked it for a year with fair results.
All of the fossils collected prior to 1882 are now in the Yale Museum, while thosefound iu subsequent years are in the United States National Museum and Carnegie
M.P. Felch.

to the attention of Professor Marsh,

Museum collections.
1 Extracted chiefly from Hatcher's account published in Armals of the Carnegie Museum, vol. 1, 19C1, pp. 333-.337, figs. 1 and 2.
= In the Annalsot the Carnegie Museum Hatcher writes: "In 1834 all work at this locality was abandoned," but a map madaFelchand collections in the National Museinn show work done there in 1886.
by

:

.

..

.

OSTEOLOGY OF IHE AKMOKED DINOSAUEIA.

'25

In this quarry the bones are for the most part found in a very hard layer ofsandstone/ though they occasionally extend down for a short distance into theunderlying clays. The bone-bearuig horizon is not more than 3 feet thick verticallyand has been worked over only a few hundred square feet, yet a wealth oi material
has been found, as evidenced by the f aunal list given below, which does not begin
to represent the number of individuals recovered.
According to Hatcher = "The bone-bearing stratum is about 150 feet above thered Triassic sandstones." He also says: "That the lowermost dinosaur beds of Garden Park are of an earlier age than those of Como Bluff."
Plan of work. The fossil bones lay buried in a thick stratum of heavily bedded
sandstone. Not only was the stone extremely hard, but it was also considerably
fractured, both vertically and horizontally, in such manner as to greatly increase
the difficulties encountered in properly taking up the bones. Mr. Felch, however,overcame these difficulties in a most commendable manner. The specimens werequarried out in laige blocks of stone, the contained fossils thus being retained in—their original relative positions.
Each articulated or partially articulated skeleton
was given a number (for example, the type of Stegosaurus stenops was designated by
the field number "Sk. 11 ").
The sksletoii was divided into irregular-sized groups,
each group being indicated by a number, as Gi. 1, Gr. 2, etc. The pieces of stonecomprising the different groups were lettered, each group beginning with A andconthiuing alphabetically. Tlie skeleton, group, and block designations werepainted on. the stone, so that, aided by the rough sketch diagrams made and properly marked at the same time, the work of assembling the blocks in the laboratory
was reduced to a minimum. Considering the early date of this work, which was
before the development of modern field methods, the painstaking care and ingenuity
displayed by Mr. Felch in collecting tliis difficult material with such success is mostremarkable.

The list that follows shows the fauna of Quarry No. 1
DiNosAxmiA

Dinosaueia* Ceratosaurus nasicornis Marsh.

*Lahrosaurusferox Marsh.
*Stegosaurus stenops Marsh.
Stegosaurus armatus Marsh.
* Morosaurus agilisM.axs\\.

*Haplocant7iosaurus priscus Hatcher.

*Haplocanthosaurus

utterhacki—

Continued.
Laosaurus gracilis Marsh.
Camptosaurus medius Marsh.
Crocodilia:
GoniopTiolis sp.

Chelonia:*Probaena sculpta Hay.
Ghjptops plicatulus (Cope)

Hatcher.
*Diplodocus longus Marsh.
Brontosaurus sp

PiscesAUosaurus fragilis Marsh.

Mammalia::* Geratodus giintheri MarshGeratodus sp

Gcdurus agilis Marsh.

Dryolestes gracilis Marsh.

[Those marked with an asterisk (*) represent typc-specim'-ns.l
1

Dr. George P. Merrill has kindly made a microscopic examination of the sandstone in which the bones were found, andhis conclusions are as follows:"The sandstone consists mainly of quartz granules with a little feklsimr and flecks of brown mica, with a relatively large
amount of interstitial calcite which serves as a cement. The grains of sand are not greatly rounded, in some cases are angular,
indicating that they have not been subjected to much wear.
I am inclined to regard them as of river, lake, or estuary origin
rather than consolidated beach sands which would, under ordinary conditions, show greater signs of wear."
2 .\nnals of

the Carnegie Museum, vol. 1 1901 p. 336.
,

.

:

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

26

OSTEOLOGY OF STEGOSAURUS.
In the pages that follow is given, for the first time, a detailed account of thecomplete skeletal anatomy of Stegosaurus. These descriptions are based entirely
upon specimens belonging to the vertebrate paleontological collections of the UnitedStates National Museum, and primarily upon the very complete skeleton, briefly
described ^ by Marsh as the type of the species S. stenops.
(Cat. No. 4934.)
I haveselected this specimen on account of its comprising a considerable part of one individual, and from the fact that most of the bones were found articulated, or at least
so little disturbed, that there can be no question raised as to their proper association.
Where important structural differences exist, reference is made to other individuals,
and bones not represented in this specimen or not sufiiciently preserved to show
their more important characteristics are described from other specimens.
Skull.
Plates 5, 6, 7, 8. 9, and 10.

The cranium belongmg to the type of Stegosaurus stenops is unique as being themost perfect skull of the genus yet discovered, and although shghtly distorted frompressure, it is otherwise most perfectly preserved, as is well shown in plate 19,
fig. 1, reproduced from a photograph of the specimen.
In the National Museum collections are five other crardi, in varying degrees
Two of these are to a great extent disarticulated. These, however,are of especial value in the proper interpretation of the elements in the articulated
skulls, and they also make possible a more detailed description of the separate bonesof the skull than could otherwise be given.
Summary of cranial materials. The cranii in the United States National Museumof preservation.

—

are as follows
1.

City, Colorado.

2.

Complete skull and jaws from Quarry No. 1, Canon
Mounted with skeleton

Stegosaurus stenops.

Collected by M. P. Felch, 1886.

No. 4934. Sectioned.
Stegosaurus sp. Disarticulated skull and portions of lower jaM\No. 4935,

from Quarry 13, diagram 4, Como, Albany County, Wyoming. Collected
by Fred Brown, 1884.
3. Stegosaurus stenops.
Occiput and brain case, with a few other elements.
No. 6645, from Quarry 13, diagram 13, Como, Albany County, Wyoming.
Collected by Fred Brown, 1887.
4. Stegosaurus sp.
Fragmentary skull and portions of lower jaw. No. 7637,
from Quarries 13 East and 13 Middle, Como, Albany County, Wyoming.
Collected by W. H. Reed, 1882.
5. Stegosaurus armatus Marsh.
Posterior half of skuU. No. 4936, Quarry No. 1,
Canon City, Colorado. Collected by M. P. Felch, 1884. Sectioned.
6. Stegosaurus stenops 1
Posterior portion of skull. No. 2274, Quarry 13, diagram
Collected by Fred Brown, 1885.
5, Como, Albany County, Wyoming.
1Amer. .lour. Sei., ser. 3, vol. 34, 1887, p. 414.

.

OSTEOLOGY OF THE ABMOKED DINOSAUKIA.

Known elements of the Stegosaurian skull.

27—

Alisphenoid
Angularan

Postfroiital

Articulai-ar

Posts Lipraorbital.

no. so

pf

al.

sp

Postorbital

pg
pQ J-

Basispheiioid

Js

Pi'efrontal

Basioccipital

60

Preiaaxillaryp^

Deutary^

Prearticular„ ^^Exoccipitalex.oPredeiitary

FrontalyPresupraorbital

pj
p sq

j

Prootic

i

Pterygoid

Jugal

Lachrymal

pj.Q
-

m

Quadratejj

Quadratojugal

Orbitosphenoidor.sp

Splenial

Palatinepi

Squamosal

MaxillaryNa-salqj
g

Prespheiioidp,spSurangularParaoccipital (opisthotic)

p.ocnSupraoccipitalParietal

pi
«

Vomer

g„
jq

gg
„

.

<^—i:^
3.— Skull OF Stegosaurusstenops Marsh. Lateralview. Type. Cat. no. 49.M, U S N M
LE.SS THAN 1 NAT. SI2K. a. ANTERIOR NARES; an,
ANGULAR; ar, ARTICULAR; b, ORBIT; C, tNTBATEMPORAL F0S.<!A; d. DENT.VRY; j, JUGAI,; l, LACHRYMAL; m, M.LmLARY; n.NA.SAL;

FiQ.

condyle;OC, OCCTPrTAlp.ar,prearticular;pri, predentary;pf, prefrontal; pm, premaxillaey- pn
POSTORBITAL; p. OC, PARAOCCIPITAL; po.so, POSTSUPRAORBITAL;
p.SO, PRESUPRAORBITAL; 7, QUADRATE; qj, quadratojugal; s, splenial; sti, surangular;,??,squamosal.

Description.—A study of this material shows that Marsh's figuresof Stegosaurus stenops,of the skuU
which have appeared in numerous Americian and European

pubhcations, are incorrect in many of their details. The
inaccuracies are in greatpart due either to the complete coalescence or to the obscurecondition of many of
the sutures, and also in some instances to a wrong
interpretation of cracks in theskull (No. 4934) as representing sutural articulations.
These errors have been corrected in the drawings, and a more detailed mention ofthem will follow in thediscussion of the separate skull elements.
Viewed from the side (pi. 5 and fig. 3) the skuU of Stegosaurus is longand slender,
the facial portion being especiaUy produced.
With the jaw in position the outline of
the skuU IS wedge shaped, the apex being directed forward.

The nai-es are long,
The orbit is large, measuring
about one-fifth of the total length of the skull, and placed
well back. The infratemporal fossae ai-e somewhat smaller. Marsh has pointed out that"all of these
and, asm Gamptosaurus, are situated well in front.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

28

openings are oval iii outline and are in a line nearly parallel with the top of theskull."The great vertical depth of the median part of the lower jaw is especially noteA measurement taken below the orbit shows it to be over one-half theworthy.

whole depth of the head, an unusual proportion in dinosaurian anatomy.
From a superior view the wedge-shaped form of the skull is still apparent.
The only visible openings are the small subcircular supratemporal fossae. There
are no supraorbital vacuities as found in Oamptosaurus and Iguanodon, this region
being entirely roofed over by the supraorbital and postfrontal bones. This view
is wellshown in plate 6.

Viewed from the back, as shown m plate 9, figure 2, theskull and mandible

present a nearly quadrate outline.
In its general proportions and outlines the skull of Stegosaurus is found to resemble
that of Oamptosaurus more nearly than that of any other American dinosaur, thoughshould be borne in mind
that the shape and arrange-itment of their constituent elements differ considerably.
Basioccipital (ho.).
basioccipital—The

terminatedposteriorly by a moderately
broad, rounded occipital condyle.

is

The smooth articularsurface is continued forward

on the underside (pis. 5 andOc).
The condyle in No.
Cat.no.2274,U.S.N.M. J Nat. size. 65, Ba.sioccipital; £x.o, exocotital; 4Q04„„„ JJp „1^J„ narrower^^"^^ J^^ COUSKieiaoiyp, pariet.u.; p.oc, paraoccipitai.; so, supbaoccipital; Sj, squamosal.
transversely than in skulls
Nos. 2274 and 6645, as may be seen by comparing text. figures 4 and 5 with figure
The occipital condyle is inclined ventrally to the longer axis of the2, plate 9.
skull, so that when articulated with the neck the longer axis of the skull would
form an obtuse angle with the axis of the anterior cervical vertebrae, as it does in
Oamptosaurus, Trachodon, Triceratops, and Diplodocus.
The basioccipital articulates, as shown by the detached element in specimen
No. 4935, with the basisphenoid by a deep vertical suture, without a median tongueIn front of the condyle the inferior
like extension, as found in Camjitosaurus.
surface is deeply concave longitudinally, and convexly rounded transversely, andwithout median pit, as found in some predentate dinosaurs. On the anterior
median part of this surface is a notch between the blimt basioccipital processes.
These abut against similar processes on the posterior end of the basisphenoid (pi. 7).
The naedian line of the superior surface is shaUowly concave transversely and forms
the floor of the foramen magnum. On either side are the beveled, sutural surfaces
for articulation with the exoccipitals.
The exoccipitals, as in Oamptosaurus, participate Lii the formation of theFig. !.— Posterior view ofthe skull or Stegosaurus stenops? Marsh.

occipital condyle.

(See fig. 4.)

Exoccipital (ex. o.)—7,

and Paraoccipitai (p. oc). The exoccipitals are the largest
They form the lateral boundaries of the foramenbones of the occipital segment.

—

OSTEOLOGY OF THE AEMOKED DINOSAUELA..

29

magnum, and, as mentioned above, contribute to the formation of the occipital.condyle.

Viewed posteriorly they rise from heavy expanded pedestals that rest

laterally on the oblique lateral surfaces of the basioccipital, as shown in figure 4.

The upper portion develops avertically

expanded wing-like paraoccipital

process, which extends outward and backward at an angle of 45° to the main axis

Dorsally
the exoccipitals are united by the widely expanded supraoccipital, and the unionof these bones is greatly strengthened by the processes developed on the posteroexternal angles of the supraoccipital, which lap along the upper posterior surfacesof the exoccipitals, forming a longitudinal swelling of the bones at this point (pi. 9,of the skull, ending at a point posterior to the occipital condyle (pi. 6).

The dorsal border of the paraoccipital process supports
the parietosquamosal processes. In specimen No. 2274 the squamosal passes fromthe dorsal to the anterior surface near the outer end, as shown in figure 4, but in No.
4934 the squamosal ajipears to cover the entire dorsal border (see fig. -2, pi. 9).
The other sutures of the occipital region in this specimen are coalesced and thefig. 2, also text figs. 4 and 5),.

union of the elements can not beclearly determined.
In specimen
No. 4935 the right exoccipital iswholly detached and shows beauti-„

fidly the chief characteristics of thisbone.

The opisthotic and exoccipitalin Stegosaurus evidently unite earlyin life, for in none of

the skulls isthere any indication whatsoever oltheir sutural union.

These coalesced bones unitewith the prootics by a long lapping suture on the anterior surface.

The end of the paraoccipital process

Posterior view of the skuli. of Stegosaukds stenops?
Maesh. Cat. no. 6645, U.S.N.M. k Nat. size, bo, B.vsioccipitai.;&.0, ExocciPiT,\x; /m, foeamen magnum; PiPaeietal; p.oc, paeaoccipital; so.supeaoccipital; S?, squamosal.

Fig. 5.

broadly roimded from above
downward, and in the articulated skull the lower half projects free, and hides th(>upper end of the quadrate from a posterior view.
The exoccipital is pierced by two small foramina. The more posterior one
enters the brain case just within the entrance of the foramen magnum and serves
as exit for the twelfth or hypoglossal nerve (XII, fig. 10).
Anterior to and separated by a thin wall of bone from the exit for the twelfth nerve is the anterior
iscondyloid foramen.

—

Supraoccipital (so.). The supraoccipital in Stegosaurus, as in all other predentate dinosaurs,' where the elements of the skull are known, forms the upperboundary of the foramen magnum.

Viewed from behind the supraoccipital is a comparatively wide bone, wedged
The median dorsal border does
not unite by suture with the overlying parietals, but, as in Camptosaurus has ain between the exoccipitals and parietals (fig. 4).

.

4• F. von Huene has recently shown that the supraoccipital in Tr'iccratops extends tn the foramen magnum.
bnch, vol. 2, 1912, pp. 147, 148, flgs. 1 and 2.

See Neues Jahr-

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

30

was probably covered by cartilage. In very old individshown by specimen No. 6645 (fig. 5);
On the posterior surface is a blunt vertical median ridge extending from the upper
border of the foramen magnum to the top of the bone. On the latero-ventral
angles thin processes are developed, which extend outward and backward and lap
along the exoccipitals. The posterior surface is inclined forward from the verVentrally it articulates by wide, oblique, heavy sutural
tical at an angle of 35°.
The anterior surface is deeply excavated andsurfaces with the exoccipitals (fig. 4).
forms a considerable part of the posterior boundary of the brain case. On theanterior lateral borders, well shown in specimen No. 6645, are notches which reachthe exterior by an opening between the supraoccipital and parietal. These would
finished surface, wliicli

uals these bones sometimes coalesce, as isappear to correspond with those noted by Hay in the brain case of Triceratops.
They probably transmitted blood vessels, for no nerves are known to leave this^part of the brain. Similarly placed foramina are present in the supraoccipital (Cat.
No. 5692, U.S.N.M.), described and figured by Lull ^ as belonging to Pleurocoelus
nanus Marsh. In this connection it might be well to call attention to the close
resemblance of this bone to the supraoccipitaLs of Stegosaurus and Camptosaurus,
more particularly to the latter. That it pertains to a member of the Ornithopoda
I am fully convinced and, in all probability, should be referred to the genus Dryoscuurus, as being the only representative of the Camptosauridae known to occur in
the Arundel formation.

—

Basisphenoid (bs.) and Presphenoid {p. sp.). The basisphenoid is a short bonewhich unites posteriorly with the basioccipital and dorso-laterally with the prootics,
The median ventral suralisphenoids, and slightly, if at all, with the exoccipitals.
face is deeply concave transversely, and on the latero-anterior end a pair of diverging processes are given off, which extend backward and downward, with surfaces infront near their extremities for union with the pterygoids (pi. 7). The dorsal surface
The
is continuous with the basioccipital and completes the floor of the brain case.
pituitary fossa is deep and extends backward somewhat beneath the floor of themedian vesicle (pi. fig. 3, pi. 10). At its bottom and on either side are short foramina, which lead outward and backward, opening externally into vertically elongated slits on the sides of the basisphenoid (c. fig. 10). These serve to transmit
the carotid arteries.
Anterior to tnis fossa the bone contracts rapidly to a narrow-pointed process,which probably represents the persphenoid, although its complete anterior extent

can not be determined from available material.

—The alisphenoid(See p.sp. fig. 10.)a small subtriangular bone (fig. 10)
resembling very closely the corresponding element in Camptosaurus.* Specimen
No. 4935, upon which the description to follow is based, shows the alisphenoids
detached, but in aU other skuUs they are so closely coossified as to be almost indistinguishable.
DorsaUy it unites with the parietal, frontal, and to a slight degreewith the postorbital. The outwardly turned anterior end is received in a transThe lower posterior borderverse notch on the lower and outer side of the frontal.
Alisphenoid^ {al. sp.).

1=

Pro=. U. S. Nat. Mus., vol. 3^909, pp. 103.

Maryland Gejl. Survey, Lo5^FCreta:eous, 1911, p. 192, pi. 15, flgs. 3a-c.
H. F.Osborn, Mem. Amer. Mus. Nat. Hist., new ser., vol. 1, pt. 1, p. 5.
C. W. Gilmore, Proc. U. S. Nat. Mus., vol. 36, 1909, pp. 208-209, fig. 5.

* In part the orbitosptienoid of
I

isOSTEOLOGY OF THE AEMOBED DINOSAUBIA.

31

forms the anterior boundary of the foramen ovale in much the same manner as inCamptosawnis} The external surface contributes to the inner wall of the supratemporal fossa, whUe the internal forms a portion of the brain case containing the
cerebral hemispheres.

OrUtosphenoid (or. sp.).

—The presencein the skuU of Stegosaurus of ossified

orbitosphenoids is clearly shown by two specimens, Nos. 2274 and 4936 (fig. 10, also
As shown by specimen No. 4936, upon which the following descripfig. 2, pi. 10).
tion is based, there are two curved plate-like bones, united ventrally on the medianform that part of the brain case containing the olfactory lobes. Dorsallyline tothey unite exclusively with the frontals, and posteiiorly with the alisphenoids.

Above the point where the orbitosphenoids unite in fi-ont is an opening which
undoubtedly gave exit to the olfactory nerves. They appear to have left the brain
through this single orifice {ol., fig. 2, pi. 10), at least no bony partition separatingthem has been observed. On the posterior borders of these bones are foramina
for the exit of the second, third,

Parietal (p.)

and fourth nerves.

—The dorsal portion of the parietal segment of the skuU

isformedby the parietal, an unpaired element in Stegosaurus, as in all known dinosaurian
skulls.

Viewed from above, the parietal is a short, heavy bone with laterally expanded
The superior surface is flattened and without median longitudinal crest or
The median lateral surfaces drop abruptly, at right angles to the upperridge.
The least
surface, and form the inner boundary of the supratemporal fossae.
transvei-se width of the paiietal between the fossae in No. 4934 measures 34 mm.
Anteriorly it unites with the broad frontals by an evenly (in No. 4934) rounded
imbricating suture (pi. 6). In other specimens this suture is more angular, as
shown in figure 1, plate 10. The antero-lateral angles meet the postorbital andpostfrontal and in S. stenops excludes the frontal from the supratemporal fossa.
In S. armatus (fig. 1, pi. 10), the frontal participates in the boundary of this fossa.
Latero-posteriorly are vertically expanded processes, which extend backward andends.

outward along the top of the supraoccipital, meeting a branch of the squamosalby a lapping suture about the center of the posterior boundary of the supratemporal
The median posterior border of the parietal thins out to a rounded edge,
fossa.
which in most skulls slightly overhangs the underlying supraoccipital. The medianventral surface is hoUowed out transversely and forms the piincipal part of theroof of the brain case.
Frontal (/.). ^The fi'ontals are paired bones, although in old individuals the
suture coalesces. Above the orbits they are thick and heavy, with a sutural edge—

15 mm. long between the anterior process of the postorbital and the posterior
process of the prefrontal which unites with the postfrontal. They overHe theViewed fi-om above theparietals posteriorly as is shown by specimen No. 6645.
From this view each bone sends out a sharp narrow anterior
frontal region is flat.
process which unites on the median Hne between the posteriorly directed fingerlike
processes of the nasals. The nasal processes overlie the frontals, being received
in the longitudinal grooves shown a,t ns., figure 1 plate 10.
,1Compare flg. 5, Proc. U. S. Nat. Mus., vol. 30, 1909, with flg. 10,

i.

e.,

External to these groovesby the development of a slender process whichmeets the basisphenoid, well shown in a skull of S. armatus (Cat. No. 4936, pi. 10.)

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

32

the antero-external part of the dorsal surface is concavely beveled for the anticuatioii with the overlying portion of the prefrontals (ps., fig. 1, pi. 10).

The postero-external angles of the f rontals are much thickened and are roughly beveled for suturalunion with the anterior internal process of the postorbital.

As mentioned previ-

ously, in S. stenops, the frontal is excluded from the supratemporal fossa, but reaches
itin a skull of S. armatus, No. 4936.

(See fig. 1, pi. 10.)The posterior ventral

surface is concave transversely and foims the roof covering the olfactory lobesof the brain.

The orbital margin is horizontally concave.
The prefrontal, as shown in specimen No.
(pf.).

—

4934, is anelongated subeUiptical bone which overlies the superior surface of the frontal andnasal bones at their junction (pf., pi. 6). The outer border articulates with thepostfrontal and presupraorbital bones and more anteriorly it meets the lachrymal.
Prefrontal

The posterior end is separated from the anterior process of the postorbital by anintervening part of the frontal measuring 15 mm. on the superior surface.
The postfrontal, viewed from above, is an irregularly
Postfrontal (pof.).
shaped element which completely fiUs the space between the external supraorbital—bones and the postorbital and prefrontal, and frontal (see pof., pi. 6 ). The dorsal
surface of this element is rugosely roughened, and it unites with the frontal by acomparatively short sutural edge.

I

was at first inclined to regard this elementof the skull as a supraorbital bone, but I

am indebted to Dr. R. Broom for firstpointing out to me that it should be identified as the postfrontal, and that theso-caUed postfrontal, postorbital complex represents only the postorbital. That
this is the proper relation of these elements appears to be indicated by a very
similar arrangement found in the disarticulated skull of a small Ceratopsian,Brachyceratops montanensis ' Gilmore, recently acquired by the National Museum.

—The postorbital is a triradiate bone with one short, stout
inward and uniting with the frontal and parietal; a second
posteriorly directed branch unites by squamous suture with the outer surface ofthe squamosal and forms the tipper temporal bar; the third, the longer one of thethree, is a descending process which overlaps exteinally an upgrowth from thejugal and thus forms a postorbital bar separating the orbit from the infratemporal
Postorbital (po.).

process, extending

The latter process, as in Camptosaurus, is trihedrial in cross-section. It
descends to the lower border of the orbit (see po, pi. 5), not part way as in Camptosaurus, Trachodon, and Iguanodon.
On the external surface at the junction of thethree branches is a roughened protuberant area over which the hoUowed out
opposing surface of the postsupraorbital is attached. The postorbital as here
identified, is in part the postfrontal of Marsh.
Prooiic (pro.).
The prootic is not clearly differentiated in any of the skulls
before me, although its approximate position and relationships can be determined.
As in Crocodylus and Camptosaurus, this bone fills the area between the basisphenoid
below, the alisphenoid in front, and the parietal and supraoccipital above, and in
all probability the opisthotic behind, although the prootic and opisthotic are so
fused as to be unrecognizable as separate elements. The foramen ovale in thealligator and in Camptosaurus is between the prootic and alisphenoid, the larger
part of it being in the prootic.
This foramen occupies a similar position in Stefossa.

—'

Smiths. Misc. Coll., vol. 63, 1914, p. 5, pi. 2.

OSTEOLOGY OP THE AKMOKED DINOSAUKIA.
gosaurus, as plainly shown by specimen No. 6645.

33

On the lower lateral surface

this bone is pierced by a small foramen (VII, fig. 10) for the exit of the seventh orMore posteriorly the prootic forms the anterior border of the internal

facial nerve.

auditory meatus (VIII, fig. 10).

—LacJirymal^ (L). The lachrymal as seen in specimen No. 4934 (see I, pi. 5)
a small, irregularly shaped bone lying wedged in between the maxilla, nasal,

isjugal, and prefrontal.

It is overlappedon the upper posterior border by thepresupraorbital.

—

Supraorbitals {p. so and po.so).
The supraorbital in Stegosaurus is composed of two separate pieces, which as a matter of convenience, in referrmg tothem, I shall designate as the pre- and post-supraorbital bones (see p. so and p>o.
so, pi. 6).
In Scelidosaurus as described by Owen in his Fossil Reptilia of the
Liassic (p. 10), the supraorbital is present but consists of a single bone.
Marsh,^ as shown by his figures of the skull, based upon specimen No. 49.34,
has considered the supraorbital as consisting of one element.^ In this, however,
he is in error, as clearly shown by two partly disarticulated skulls, Nos. 6645 andIn fact, now that it is known that there are two bones in this region, the4935.
sutures appear quite distinct in No. 4934, and the outlines of the elements can be
These elements make a complete roof
clearly traced, as indicated in plate 6.
over the orbit, there being no supraorbital fossa as found in Camptosaurus and Iguanodon bernissartensis. The articulated supraorbital bones are well shown in the
From a lateral view, see fig. 3, the postsupraorbital isskull of S. stenops No. 4934.
a small triangular bone which overlaps the antero-lateral surface of the postorbital.
It forms the rounded postero-dorsal boimdary of the orbit, and extends forward
above the orbit nearly to its center where it unites by a straight transverse sutm-e
with the presupraorbital. The presupraorbital is a comparatively long, nari'ow,
cxirved bone which completes the upper boundary of the orbit, and unites in front'with the prefrontal and lachrymal. As shown in plate
form the external boundary of the upper half of the orbit.

Nasals (n.).

6,these two elements—The nasals are long bones and form theupper surface of the snout.

gi-eater portion of the
Posteriorly they articulate with the frontals by over-lapping finger-like processes, while in tui-n they are overlapped on this end by theprefrontals.

(See pi. 6.)

Laterally, the nasals turn abruptly down to unite with the maxillae and pre-and are only slightly in contact with the lachrymals on the inferoThe pointed anterior ends are overlapped by the backwardly
The upper surfaces of these bones are
directed processes of the premaxillae.
maxillae,posterior angles.

throughout the greater part of their length, although transversely
rounded above the narial orifice. The nasal in specimen No. 4934 measures 248

flattened

mm. in length.

—

Premaxillae (pm.). In Stegosaurus, as in all known predentate dinosaurs
excepting HypsilopJiodon foxii, the premaxillary bones are edentulous. In skull'

Adlachrymal ot Gaupp.

Beitrage zur Kenntnis des Unterkieters der Wirbelthiere.

Anat. Anz., vol. 39. 1911.

» Amer. Journ. Sci., ser. 3, vol. 34, 1887, pi. 6, figs. 1. 2, 3.

and Amphibia, pt. 1, 18S8,p. 176. Lydekker inafootnote comments on the skaUot Stegosaurus
as follows: "This bone forming the upper border of the orbit and connecting the pre- and post-frontals appears to be an element
3 Catalogue ol Fossil Reptilia

usually not represented as a distinct bone."

34

BULLETIN 89^ UNITED STATES NATIONAL MUSEUM.

No. 4934, that part of the bone visible on the outer surface is an oblong, oblique
Posteriorly it sends
plate, the upper border of which js notched by the nostril.
backward a gradually narrowing process which is intercalated between the nasal andmaxillary, terminating at a point about midway between the narial and orbital
The regularly curved, anterior end of the premaxillary is continued
openings.
upward into a posteriorly directed process which overlaps the anterior end of theOn the anterior ends ofnasal, thus completing the boundary of the narial orifice.
the cojoined premaxillae the median surface is transversely concave, leaving two
diverging ridges extending down toward the latero-extemal angles of the nose.
The sxirface of these bones is comparatively smooth, not rugose as in Camptosaurus.
The palatal surface is hollowed out transversely. The right premaxillary of No.
4934 has an alveolar border 61 mm. in length. The greatest width of the articuThe more important features of the premaxillary
lated premaxillae is 59 mm.
In No. 4935 the posteroare well shown in plates 5 and 6, and plate 9, figm-e 1.
internal borders are shown to be in contact with the vomers.
Maxillae int.). The maxillary is a large bone of rudely subtriangular outline,
whose outer surface forms the greater part of the cheek portion of the slaiU (pi. 5,m). Its superior border meets the premaxillary, nasal, and lachrymal bones.
Posteriorly it articulates externally with the jugal and internally with the palatines.
In advance of the dentigerous portion of the maxiUa, a triangular flattened extension
is apphed to the lower median surface of the premaxillary, terminating somewhat
forward of the center of the narial opening. In specimen No. 4935 this end appears
The right maxillary of No. 4934 has a height ofto be in contact with the vomer.
54 mm. above the dentigerous border at its center. The dental or alveolar border
In thisis swollen transversely, the teeth being placed on the internal margin.
maxillary I am able to count an unbroken series of 22 teeth and there may havebeen two or three more on the anterior end. The 22 teeth occupy a longitudinal
space of 129 mm. A fragmentary maxilla belonging to specimen No. 6645 shows
the usual row of foramina which pierce the bone above the level of the tooth roots.
The greatest length of the right maxillary of No. 4934 is 214 mm.
Jugal {j.).—T\ie jugals are preserved in situ in No. 4934, as shown in plate 5, j.
They are long slender bones with expanded ends, which form the lower boimdaries
On the upper posterior end an ascending process underlaps a descendof the orbits.
ing process from the postorbital, and with the quadratojugal completes the postPosteriorly it meets the quadratojugal by squamous suture. Anorbital bar.
In
teriorly, it appears to overlap the maxillary and lachi'jonal by a flattened end.
his pubhshed drawings of this slcuU, Marsh indicates the anterior termination as
being posterior to the anterior boundary of the orbit, but a close examination of thespecimens shows that they extended some distance in advance of this point, as
indicated in the corrected drawing (pi. 5). The greatest length of the right jugalof No. 4934 is 109 mm.
Quadratojugal (qj.). -The quadratojugal, as shown by specimen No. 6645
(see qj., fig. 6), is a small irregularly shaped bone, having a much expanded posterior end which articulates suturally with the lower postero-extemal side of thequadrate. A comparatively thin, finger-hke extension is directed forward and laps
along the inner side of the posterior extension of the jugal. In this specimen it has agreatest length of 50 mm.

——

OSTEOLOGY OF THE AKMOKED DINOSAUEIA.

35

On account of the complete coalesence of the quadrate with the quadratojugal
in the skull of S. stenops, No. 4934, Professor Marsh was not able to detect its
presence as a separate element, and in the original drawLags of the skull it was indicated as a forwardly directed
process of the quadrate.

Quadrate (q.).

—The quadrate, alarge, stout bone, istransversely compressed throughoiit its upper half into aquadrangular plate. Toward the distal end, however, it
thickens in aU dimensions. In the skuU of S. stenops (No.

4934) both quadrates have been retained in their natural
relations and are but little distorted. (See fig. 2, pi. 9.)
The right quadrate of this specimen has a length of

129 mm. the left element, which has been more subjected
somewhat shorter. The antero;

to vertical pressure, isposterior diameter of the quadrate (right), just below thesquamosal end, is 39 mm. and just above the mandibular
end is 24 mm. The transverse width of the latter end;

is

33 mm.

Viewed from the side the quadrate is capped by thesquamosal, the truncated top, fitting within a recess on theunder side of that bone. On the posterior internal side
(shown by the quadrate of No. 6645, see fig. 6), below
the squamosal end, a flattened, slightly striated surface
rests against the outer anterior face of the paraoccipital

Near the middle of the quadrate a verticallyflattened process is given off, which extends anterior toprocess.

Fig. 6.— Left quadrate and quai>

KATOJUGAL OF STEGOSAUKUS
STENOPS? Marsh. Cat. no. 6645,
U.S.N. M.
Side
Nat. srzE.
5
VTEw.
a, Articular end
for

LOWER mandible; b, END

WHICIlMEETS THE SQUAMOSAL; q, QUADRATE; qj, QUADRATOJUGAL.

the longer axis of the bone. This internal process turns shghtly mward and unites
by a lapping suture with the posteriorly directed process fromthe pterygoid (see pt., pi. 8).
The articular end for the jaw is rectangular in outhne.
Viewed from behind the articular end is cut off obliquelyThis view also
to the longer axis of the bone (fig. 2, pi. 9).
shows on the posterior surface the pronounced longitudinal
depression in the shaft of this bone. Text figiu-e 6 is based
upon the detached quadrate of No. 6645. In old individuals
Fig. 7.—Ventral view of left

the quadrate appears to become fixed, as shown by specimens
Nos. 4934 and 4936.

—

SQUAMOSAL OF StF.GOSAURUS
stenops? Maesh. Cat. no,

Squamosal {sq ). The squamosal, as shown in pi. 5,
by an anterior branch with the postfrontal and by
a shorter, heavier, inner process with the parietal. It thusT!
sutue.^l surface
helps to bound the supratemporal fossa posteriorly. Inunites with parietal;
ternally the lower posterior edge rests upon the upper
extends
which
process
forward to MEET THE POSTborder of the paraoccipital process, but more externally it
FRONTAL.
(See figs. 4 and 5.)
passes below and in front of that bone.
It caps the upper end of the quadrate, which is fitted into a recess on its under
6645, U.S.N. M.

Nat. size,a, Surface for articulation
quadrate;
WITH theside.

JunitesA ventral view of this bone is shown in figure 7.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

36

Pterygoids (pt.).
ft., plate 7.

—The pterygoids are irregularly shaped bones, as shown in

On the latero-posterior borders two diverging processes are developed,

which extend backward and outward, and articulate on the inner side by a long,lapping suture, witn anteriorly directed processes from the quadrates. On theinternal posterior border, where these processes leave the body of the pterygoid,itunites withthe descending basisphenoid processes.

On

the latero-anteriorborders two spatulate processes are given off which extend forward and outward.
Whether these processes unite with the palatines, or whether there is a transpalatine,
as in the crocodile and some other reptiles, can not be determined from this specimen, because of the incomplete and damaged condition of tliis region. On the
median ventral surface of the pterygoids a downwardly directed angular process
Tliis process is strongly braced by vertical lamina extending down
is developed.
on the sides and back (fig. 2, pi. 9). Above and behind this process and at the junction of the pterygoids with the basisphenoid is a large opening that appears to leadforward into a chamber above the pterygoids, and which may represent the posterior narial opening.

From the forward face of the descending process just described is a verticalplate of bone extending well forward in the roof of the mouth.

It is likely thata portion of this plate represents the vomers, but the sutural junction of these elements can not be determined from this specimen.
Palatines (pi.). That the palatines are present there can be no doubt, but it—

is impossible

from the present specimens to get anything like an adequate idea of

The irregularly tritheir extent, or relationships to the surrounditig elements.
angular elements in front of the pterygoids, as represented in plate 7, were identified
by Marsh as the palatines. We can not be certain, however, that the openings inthe bone and their inner contours exist as depicted.

—

Vomer (v.). Specimens Nos. 4934 and 4935 (v., pi. 7) show the vomer to havebeen present in Stegosaurus, but it is impossible from available specimens to determine their true extent or relationships.
Epipterygoid.
The damaged condition of this part of the palate in the skullof No. 4934 makes it impossible to positively identify this element.

—

Measurements of shull of Stegosaurus stenops, No. 4934-

Type.

mm.
Greatest length of skull, taken at center

414

Greatest expanse of paraoccipital processes

142

Greatest expanse above center of orbits

156

Greatest expanse above center of nares

18

Distance from posterior border of orbit to posterior extremity of squamosalDistance fi-om anterior border of oi-bit to anterior extremity of premaxillae

104

Distance from extremity of premaxillae to distal extremity of quadrate
Distance from distal end of quadrate to top of skull

Height of skull over center of maxillary (estimated)
Height of snout at anterior border of narial opening
Height of skull with lower jaw, measurement taken at center of orbit
Same measurement taken below posterior border of nares
Transverse diameter of occipital condyle
Antero-posterior diameter of orbit
Antero-posterior diameter of narial opening

251
400
149
71

40
144

90
39

91
75

—

OSTEOLOGY OF THE AEMOKED DINOSAUEIA.

37

Lower Jaw.
Plates 5, 7, 8, and 9.

is

The mandible iii Stegosaurus consists
present there are 15.
The dentary,of13elements, andangular,surangular,

if

the coronoid

articular,pre-articular, and splenial are paired bones, the predentary being single and articulatingwith the ends of both rami. The coronoid, a paired element, is probably present,
but its presence or absence can not be determined from the available specimens.

The following description of the several elements of the lower mandible is toa great extent based upon the well-preserved jaws of S. stenops, No. 4934. It
might be well, however, to explain that the jaws were found articulated with theskull, to which they are so closely applied that it has been deemed unwise to attempt
their separation.

—

Dentary (d.). The dentary, as in all dinosaurs, is the largest bone of the manIn Stegosaurus it is especially remarkable on account of the extreme transverse thinness of the lower half and the wide shelf of bone exterior to the row ofteeth on the dorsal border. These features are best shown by the portion of theright dentary pertaining to specimen No. 4935, shown in figure 8. The transverse
width of the medianlower border of thisbone is 7 mm.; thedible.

same

measurementof the dental border
is

21

mm.

The ex-tern al surf ac e is c om-

paratively

smoothand flat,verticaland thediameterdecreases

gradually

from

back

Anterior elilf of right dentary of Stegosaurus sp. Cat. no. 4935, U.S.N.M.
Size. Internal vte-w. a, Anterior end; p, posterior end; s, symphtsul
Shows the complete dental series of the lower
as consisting of
23 functional teeth.

Fig. 8.

towardJNat.

SURFACE.

mw

Below the anterior border of the orbit, in specimen No. 4934, it has adepth of 68 mm.; below the posterior border of the nares a depth of 41 mm.
The anterior end curves downward (fig. 8) and inward, the two dentaries
forming a "spoutlike" symphysial end as in Camptosaurus.
The dorsal border is comparatively wide, the tooth row being placed on theextreme internal border. Along its external border, beginning opposite the first
tooth, a ridge gradually rises from this surface until opposite the last tooth it
attains a height of 17 mm. above the border of the alveolus.
Between this ridge
and the dental series is a row of foramina, which evidently correspond to those on
the external surface of the Camptosaurus dentary, and which doubtless served forthe transmission of nerves and nutrient blood vessels to the lips. These foramina
lead to a canal traversing the length of the heavier part of the bone and which opens
anteriorly near the symphysis.
This is the mental foramen through which a branchof the fifth nerve emerges.
The anterior part of the dorsal border where it turns down to meet the predentary, is shallow though broadly grooved. On the internal side of the dentaryof No. 4935 (fig. 8) alveoli for 23 teeth can be counted. These occupy a space
the front.

51873°—BuU. 83—14

i

.

38

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

114 mm. in length.
horizontal aspects.

.

The tooth row is curved slightly in both the vertical and
The mandibular fossa is present and on the posterior half

extends well up between the thin outer wall and the heavier dentigerous part ofthe dentary. Inferiorly and latterly this fossa is partially inclosed by the splenial
which laps along the inner side to a point below the &st tooth. Posteriorly thedentary meets the angular and surangular.

In all probability, as mentioned pre-viously, it articulates with the prearticular on the postero-internal side.

It appears

that these elements do not coossify even in old individuals.

—

Predentary (pd.). The predentary has been preserved in situ in the skull of
No. 4934 (pd., fig. 1, pi. 9). Although imperfect in some of its details, it nevertheless gives a good idea of its chief characteristics and manner of articulation withthe dentaries. Viewed from the front it appears as a narrow, transversely curvedbone, resting upon the beveled ends of the dentaries. On the median ventral
border a narrow pointed process is given off which projects downward and backward, being interposed between the ends of the dentaries at the symphysis.
The predentary is wider transversely than the combined premaxillaries, but does
not extend so far forward as those bones. (See pd., pi. 8.) The median anterior surface is somewhat flattened and with the forward ends of the dentaries forms therather truncated end of the mandible. This surface of the predentary is pitted bynumerous but irregularly placed pits. In life this bone was probably envelopedby a horny covering and when in contact with the premaxillaries similarly covered
must have served as an efficient organ for gathering the plants upon which theanimal fed.
Splenial (s.). The splenials are long, thin bones that are closely applied tothe internal side of the dentary (s., pi. 8). They reach a point 60 mm. posterior to
the symphysial border in front, and posteriorly they inclose internally and inferiorly
the mandibular fossa. Posteriorly they extend back to a point 83 mm. from theend of the ramus and lap along the angular and prearticular. Below the junctionof the dentary and angular on the infero-lateral border the splenial is visible for ashort distance from a lateral view (s., pi. 5).
Angular {an.). ^The angiolar is also a long, thin element, which forms the outerand lower part of the posterior portion of the ramus. Dorsally it unites with thesurangular by a nearly horizontal suture. In specimen No. 4934, however, as
shown in plate 5, the anterior half of this suture has been entirely obliterated andthe union of the angular, surangular, and dentary is obscure.
The anterior end appears to be overlapped by the dentary on the outside andby the splenial on the inside. Posterior to the end of the splenial the ventral
border of the angular is swollen transversely and underlaps for a short distancethe ventral border of the prearticular (see pi. 7), but more posteriorly it returns
to the external side of the articular terminatmg in a sharp end somewhat anterior——

to the posterior termination of the sxirangular.

—The surangular

a comparatively thin, flat bone, and the
VentraUy it sends forward a thintapering extension which laps along the outside of the dentary. Posteriorly the

Surangular (sa.)

islargest of the posterior elements of the jaw.

surangular forms the upper border of the posterior one-third of the ramus.

Near

^

.

OSTEOLOGY OF THE AEMOKED DINOSAUEIA.

39

the posterior end the upjier border is deeply cut out, only a narrow part of thebone extending posterior to the articular end of the quadrate in the articulated
jaw. (See sa., pi. 5.) Internally it laps along the articular and also the prearticular.
It does not contribute to the formation of the cotylus of the lower jaw, as in Gamptosaurus.

The external mandibular foramen found in the surangular of Oamptosato-

rus, Iguanodon, and Triceratops does not appear to be present in this genus.

Articular (ar.).

—The articular

is a small block-Hke bone that forms

the greater

embraced below by theprearticular, while on its external surface it is lapped by the angular and surangular.
In specimen No. 4934, upon which the 'present description is based, this element
has a transverse width of 35 mm. On the median posterior border it has a verticaldepth of 15 mm. On account of the articulating quadrate bones the anterior
extent of this element can not be determined. The manner in which the angular,surangular, prearticular, and articular unite is well shown in plates 7, 8, and inplate 9, figure 2, which show all of these bones in their normal relations to one
portion of the articular surface for the quadrate.

another.
Prearticular(p. ar.).

It

is—Marsh in his representations of the lower jaw of Stego-saurus, did not recognize the presence of the prearticular but called the combined

elements^ the articular (ar.). Since this element has recently been found in thejaws of other members of the Predentata, i. e., in Oamptosaurus by Gilmore' andin Triceratops by von Huene * it was not surprising to find it existing as a separate element in Stegosaurus. An examination of the jaws of No. 4934 showed
clearly on the posterior ends of both rami the presence of a suture between thearticular and an element which embraced it on the inferior surface, and which is
identified as the prearticular'' (p. ar., pis. 7 and 8).

In Stegosaurus the prearticular is a moderately long bone, lying internal to the
angular which underlaps it for some distance on its median inferior border. The
anterior end of the prearticular in the articulated jaw disappears under the overlying
splenial.

The anterior half of this element exists as a thin vertical plate of bone applied
to the inner side of the jaw, but the posterior portion changes from the vertical toa horizontal plane, gradually widening until its maximum width is reached, where it
underlaps the articular.
The truncated posterior end terminates slightly forward of the posterior extremity of the articular. A small portion of the posterior edge of this bone isvisible from a side view, just below the angular bone (p. ar., pi. 5).
Ooronoid (c.) —As mentioned previously on account of the close articulation of
the jaws with the skull in specimen No. 4934, the presence of this element can not
be positively determined.
.

'

Tn the English Translation of Zittel's Text-Book on PaleontoIoRy, vol. 2, 1002, p. 211, it Is said to he present.

Amer. Jonm. Sci., ser. 3, vol. 34, lSi7, fie. 1, pi. 6.
Proc. U. S. Nat. Mns., vol. 36, 1009, pp. 220-221.
Neues Jalirbuoh, Jahrg. 1911 pt. 2. 1912, pp. 160-161
5 Since the above was written Huene in an article in Neues Jahrbuch, vol. 37, 1914, p. 581, recognizes and describesaprearticular in the lower jaw of Stegosaurus.
2
»

*

:

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

40

Measurements of lower jaw of Stegosaurus stenops, No. 4934.

Type.

Greatest length

388

Distance between posterior extremities of rami

179

Width, across anterior extremities of rami
Height of ramus below center of orbit„. . ,.„Height of ramus below posterior border of narial opening
Width of predentary, estimated

Hyoid.

—That Stegosaurus had a well developed hyoid

63
75

41
64
is

clearly shown by speci-

men No. 4935 in the National Museum, which has the thyrohyals of both sides
preserved as shown in-orThe better
preserved element isfigure 9.

a

long,

flattened,slightly curved bar of/^\ ^-^-^^^^^^^^^^P^
"^
Fig.

9.

^^^^^^^^^\^^— Thteoht.\ls op Stegosaurus sp. Cat. no. 4935, U.S.N.M.

Relation.^^^""'shown as FOxraD in the matrix,o, o,

J Nat. size.
Anterior ends; p, po-sterioebone. Comparing itwith the thyiohyal of
Carnptosaurus which
was found in situ,^ theexpanded end probably represents thelOrWard extremity.
Sixty-eight

miHime-ters posterior to thisend, the bone reaches its maximum width of 19 mm. From this point it gradually
narrows in both directions. Posteriorly it tapers to a small, smooth, rounded end.

Dr. F. A. Lucas, in an impubUshed manuscript, obsei-ves "that judging from theirlength it seems probable that these reptiles were provided with extensile tongues."

The principal measurements are as follows
Greatest length

174

Greatest width of anterior end

18

Greatest width of posterior end

7

External Openings in the Skull.
Supratem'poral fossae(e.).

—The irregularly rounded supraoccipital openings

situated one on either side of the parietals are comparatively small ia Stegosaurus.
In S. stenops these fossae are bouaded anteriorly by an inner branch of the postorbitals and the outwardly curved ends of the parietals.

In skull No. 4936, identi-

armatus, the frontal also contributes to this boundary (fig. 1,
Internally the boundary Js formed by the parietals, posteriorly by pro-fied by Marsh as S.
pi. 10).

cesses from the parietals and squamosals which meet at the posterior center of the

opening, externally by branches of the postorbital and squamosal.
Infratemporal fossae (c). The infratemporal fossae are vertically elongate,
openiags with their greatest diameter inclined at an angle of 45° to the longer axes—

These fossae are bounded above by the postemporal barof the skull (c, pi. 5).
formed by processes of the postorbital and squamosal bones; anteriorly by the'C.

W. Gilmore, Proc. V. S. Nat. Mus., vol. 36, 1909, p. 224, pi. 9, fig. 2, h.

.

.

OSTEOLOGY OF THE AEMOEED DINOSAUEIA.

41

postorbital bar formed by the united processes of the postorbital and jugal; ventrally by the quadratojugal and quadrate; and posteriorly by the quadrate.

—

Orbital cavities (h.)
The orbits are of large size, suboval in outline, the greatest
diameter being antero-posteriorly (b., pi. 5). The length of the orbit is one-fifth of
the total length of the skull. Viewed from the side it is bounded above by thesupraorbital bones; below by the jugal; anteriorly by the lachrymal and presupra-

and posteriorly by the postorbital bar as explained above. Appaiently
there were no sclerotic plates developed for the protectio"n of the eye.
There are no

orbital;pre- or supraorbital fossae in Stegosaurus, as found in Camptosaurus and Igvxinodon.

—

Anteriornares (a.). The external narial opening is of good size, subelliptical in
outline, with its greatest diameter parallel to the longer axis of the skull.
Excepting the posterior, and part of the upper boundary formed by the nasals the rest of
the orifice is enclosed by the premaxillae.

—

Posterior nares.
On the median posterior junction of the pterygoids in specimen No. 4934 is a single large foramen which apparently represents the posteriornaiial opening.

The crushing together of the bones anterior to the foramen renand thus determine its function beyond aders it impossible to trace its course

question.
While it is well within the pterygoids, the basisphenoid forms the upperboundary (pi. 7). It would appear from this specimen that the posterior nares
in Stegosaurus occupies even a more posterior position than in the recent Crocodiha
where the posterior nares are wholly inclosed by the pterygoid bones. From
Hatcher's description it would appear that the posterior nares in the Ceratopsia
occupy a somewhat similar position in relation to the bones of the palate.
Palatine vacuities. The crushed and damaged condition of this region of tlie
skull precludes the posssibihty of bounding these openings.
Foramen magnum (fm.)
Taking into coiisideration the very small size of thebrain in Stegosaurus, the foramen magnum is comparatively large. The size of
this opening, however, varies considerably in different individuals as may bereadily seen by comparing figures 4 and 5.
In most skulls it is ovate in outline'——

with the greatest diameter transverse (pi. 9, fig. 2,fm.).

In specimen No. 6645 the

As in Camptosaurus it is bounded below by thebasioccipital, laterally by the exoccipitals, and above by the supraoccipital (fig. 4).
Lesser foramina.
None of the skuUs in the National Museum collections are
sufficiently well preserved to show clearly the relationships of all of the smaller
foramina. However, the five cranii at hand supplement one another to such an
extent, that the more important openings have been recognized, and by comparing them with other reptihan skulls of both recent and fossil forms, it is beheved
greatest diameter is vertical.

—

they have been identified with a coiisiderable degree of accuracy.
Begummg with the most posterior, it is found that the exoccipital is pierced
on its lower external side by two small fcframina, one in front of the other, theposterior one being located somewhat more dorsaUy.
The latter represents theexit of the twelfth or hypoglossal nerve (XII, fig. 10).
It enters the brain casewithm the external openmg of the foramen magnum. The next anterior
foramen occupies a position essentially that of the anterior condyloid foramen injust

1Mon. 49, XT. S. Gcol. Surv., 1907, p. 36.

—

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

42

Triceratops, as identified by

Hay/ and, as he observes, "probably transmitted avein."

Anterior to the foramina just described are two larger openings shown in
IX, XI. In specimen No. 2274, from which the drawing was made,these foramina appear to be separated externally by a thin bony partition, but inspecimen No. 6645 they are confluent, forming one large opening into the brain case.

figure 10,

From the location of these openings when compared with those of other reptiUanskulls, I would identify the anterior one as the fenestra ovahs (fig. 10, VIII) and theposterior one as the foramen lacerum posterius or juglar foramen (fig. 10, IX, XI)
through which the pneumogastric, vagus, and glossopharyngeal nerves were trans-mitted.

Whether these foramina enter the brain case by distinct openings, or

ct-.pJ

celsp

'

-p'OC

Oblique side view op the posteeioe paet of tee skull of Stegosaukus sp. Cat.
J Nat. size, alsi), Alisphenoid; o.p/, aeticulak boedek foe postoeaeticulae boedee foe peefeontal; a.spo, aeticulae boedee foe postfeontal; ho, basioccipital; &s, basisphenoid; c, exit foe caeotid aeteey; eio, exoccipital;

Fig. 10.

NO. 2274, U.S.N.M.
dital;

o.pr/,

feontal; 0, CEBIT; ot, occipital condyle; orsp, oebitosphenoid; p, paeietal; poc,
PA A occipital peocess; ppc, PE0CE3S foe pteetgoid; 'pro, peoOtic; ps'p, peesphenoid;sg, squamosal; V, Vll, VIII, IX, X, XI, and XII, exits of ceanial neeves.

/,and Camptosaurus by a single foramen can not be definitelydetermined from the available specimens.
In figure 10 the foramen labeled "VII" is the exit of the seventh or facial nerve.
It has the same position as in Triceratops, Camptosaurus, and the alligator, and as
in those animals, passes straight through the center of the prootic bone.
The position of the next foramen forward of the seventh, i. e., in front of theprootic and behind the center of the ahsphenoid, at once distinguishes it as theforamen ovale, through which the third division of the trigemnial nerve always
leaves the skuU (V, fig. 10). As in Camptosaurus, this opening is largely within the
prootic, only the anterior boundary being formed by a descending process of theahsphenoid. Immediately below the foramen ovale is a deep, almost vertical fissure
on the side of the basisphenoid and from which a short foramen leads into theas in Triceratops''

rroc. U. S. Nat. Mus., vol. 36, 1909, p. 100, pi- 2, flss. I and 2, a c/.

'

OSTEOLOGY OF THE AKMOEED DINOSAUEIA.
pituitary fossa (fig. 10, c).

43This opening is for the passage of the internal carotid

The pituitary fossa is deep, extending well below the brain-case floor, andis wholly within the basisphenoid bone, as shown in plate 10, fig. 3, pi.
The foramina anterior to the foramen ovale are only shown in specimen No.
4936 in these collections (pi. 10, fig. 2). The foramina, located near the central posartery.

terior border of the orbitosphenoids, represents the exit for the optic nerves (II, fig.

pL 10). This foramen appears to be divided (not shown in the drawing) by athin filament of bone, which in an uncrushed specimen would be on the medianline.
As in Diflodocus, these foramina appear to lie wholly within the orbito2,

sphenoid bones.
On the posterior margins of the orbitosphenoids at about their middle, where
they coossify with the alisphenoids, there are notches (III, fig. 2, pi. 10), which inall probability give exit to the oculomotor nerves.
The olfactory foramen is a V-shaped opening formed by the anterior bordersof the coossified orbitosphenoids and bounded above by the frontals, and gave exit
to the olfactory nerves.
This is an unusually large opening (pi. 10, figs. 2 and 3 61).
Bhato.
Plate 10.

A cast of the cranial cavity of Stegosaurus stenops shows the smaU size of thebrain of this reptile (fig. 5, pi. 10). Its most striking features were the large size ofthe optic lobes and the small cerebral hemispheres, the latter having a transverse
diameter only slightly in excess of the meduUa oblongata. The cerebellum was
The peculiar development of the pituitary body is also noteworthyquite small.

(pi.,fig. 5,pl. 10).

In comparing the brain casts of Stegosaurus and Alligator, Mareh makes thefollowing interesting comments:

The contrast in the development of the cerebral region is marked, but in some other respects thecorrespondence is noteworthy.

In comparing the proportionate size of the brain of this living reptile with that of Stegosaurus, as
given on the same plate, the result proves of special interest. The absolute size of the two brain casts
is approximately as 1 to 10,

while the bulk of the entire bodies, estimated from corresponding portions
It follows that the brain of Stegosaurus was only 1 to 100 that of
the alUgator if the weight of the entire animal is brought into the comparison.

of each skeleton was as 1 to 1,000.

Marsh concludes that Stegosaurus had, relatively, one of the smallest brains ofany known land vertebrate.
More recently Prof. K. S. LuU makes the following interesting observations on
the brain and other parts of the central nervous system.^
The brain is remarkable for its extremely small size, the entire cranial cavity, with a length of
1.05 cm. and a width of 0.30 cm., displacing but 56 cc. of water and having an estimated total weightof but 2J ounces.

The total weight of the animal must have exceeded that of the greatest of living elephants, thebrain of which averages 8 pounds, or over 50 times the weight of that of Stegosaurus.
In comparing the relative potential intelligence of the two, one has also to bear in mind the great
preponderance of the cerebrum over the other parts of the elephantine brain, while in Stegosaurus the1

Dinosaurs of North America, Ifith Ann. Kept. U. S. Oeol. Surv., pt. 1, 1896, pp. 187-188.

2

Amer. Joum. Sci., vol. 30, 1910, pp. 371-372, fig. 9.

—UNITED STATES NATIONAL MUSEUM.

44

cerebrum constitutes hardly more than a third of the entire brain weight. The iStesrosour brain has avery large olfactory portion, small cerebellum, large medulla, and a hypophysis which is remarkable
not only for its size, but also for the peculiar shape. The sense of smell was apparently as well developed as may have been that of sight; the auditory sense I am not yet prepared to discuss.

The teeth in Stegosaurus are confined exclusively to the maxillary and dentary
They are not differentiated, the form and sculpturing remaining the same
throughout the series. Each tooth consists of a laterally compressed, verticallyThe
striated crown having denticulate margins, and a long, cylindrical fang.
^bones.

outer face of the crown is shghtly convex vertically, while the inner face is slightly
concave. There is a rounded cingulum at the base of the crown, this being more
pronounced on the exterior face (fig. 11). The denticles in cross section are roundedwith a blunt point.
isvariable.

The number of denticles on the teeth of Stegosaurus stenops

I have found teeth with as few as four and others with as many asseven on each side of"-'

the apical denticle.

Theapical denticle is always

on the median verticalline,

not posterior to it

as in the teeth of AnJcy-

losaurus ~ or Troodon.

The teeth are held in
Tooth of Sterosaukus ungui..\tu.s Maesh. a, N.vtueal size; h, c, d,twice natuea-i. size: 6, outer view; c, end view; d, top view. all after

Fio. 11.

distinct sockets.

Thoseworn out or lost throughaccident are replaced bygerm teeth developed in cavities within the jaw. Specimen No. 4934 shows
quite clearly the relationship of the germ and functional teeth (fig. 12). The
crown of the germ tooth lies on the inside of the base of the functional tooth,the crown resting against the root of the old one, and, as usual among the
Marsh.

dinosaurs, ascends or descends according to whether they are in the upper orlower series. It appears that there are not more than two teeth in a vertical
The teeth of the functional rows present a very regular cutting edge, as
series.
contrasted with the irregular series in CamptoSaurus and Triceratops. Many of
the crowns in this series (No. 4934) show marks of wear, being obliquely ground.
Twenty-two teeth can be coimted in the right maxiUary of No. 4934 and thecomplete m axillary series may have consisted of two or three more. In the dentaryWith the germ teeth, thereof specimen No. 4935 there are aveoli for 23 teeth.
were 46 in each jaw or 184 functional teeth in the complete series of the skuU.
The small weak structure of the teeth is most remarkable when the great size ofthe animalis

The oblique wear of the teeth would
was shear-like, as in the other predentate dinosaurs. The

taken into consideration.

indicate that the bite

teeth are invisible from the outside when the jaws are closed. Their weak structure
would imply, as LuU^ has pointed out, a "food of yielding character which did>

Marsh in Amer. Jouni. Sci., vol. 19, 1880, p. 255, pi. 6, figs. 4 and 5, describes and figures teeth that afterwards were lound topertain to the Sauropod genus Diplodocus.
2

Bamum Brown, Bull. Amer. Mus. Nat. History, vol. 24, 190S, p. 191, figs. 5 and 8.

3

Amer. Joum. Sci., vol. 30, 1910, p. 3fi7.

OSTEOLOGY OF THE ARMORED DINOSAURIA.

45

not require the forcible mastication of that of Iguanodon or raore especially of thelate Cretaceous Trachodon, in which thepowerful dental battery of 2,000 teeth reached
its highest perfection."
Vertebral Coltjmn.

The vertebral formula in Stegosaurus, asnearly as can be determined from available
material,isD, 17(?);
There are no truelumbars.

as follows: C, 10(«);

S, 3; C, 45 to 47.

Some uncertainty exists regarding the exact
point of separation between the cervical anddorsal region. Although slightly disarranged,
the type of S. stenops, No. 4934, shows theentire number of vertebrae in front of thesacrum (including the dorso-sacral) as being
27.

Marsh in

his

first

restoration

of

e3^-

S.

ungulatus shows 26 presacrals, 4 sacrals, and44 caudals.
In regard to the caudal series it would

appear that the tail of Stegosaurus, as in otherdinosaurs, is not made up of a constant number of vertebrae but within limits varies with

the individual.
Atlas.

—The

atlas in Stegosaurus consistsof the usual fom- pieces, the intercentrum,

neuracentra, and odontoid process. It resembles very closely the corresponding element in

Camptosaurus.
The intercentrum, as shown by specimen
No. 4934, is a subcresceiatic block of bone, theconcave side being uppermost and with thegreatest diameter transverse.

The upper pos-terior part of the transversely concave surface

receives the odontoid whUe the anterior parti%of this surface' is more deeply excavated, form-ing the lower portion of the cup for articiilation
with the occipital condyle of the skull.
On either side of this concave portion are
the articular surfaces on which the pedicels of
the neuracentra rest. Viewed from behind
this element presents a nearly straight vertical face for articulation with the axis.

Oneither side of the inferior surface are well-developed facets for the articulation of the single-headed cervical ribs shown infigure 16, r'.

UNITED STATES NATIONAL MUSEUM.

BULLETIN

46

The neuracentra are rather irregularly shaped pieces which form the sides
The articular end which rests upon the iatercentrum is expanded
The posteantero-posteriorly, having two faces which meet at an obtuse angle.
rior face rests upon the end of the intercentrum while the anterior and smaller oneof the two looks inward and forward and contributes to the formation of the cupof the neural arch.

for articulation with the occipital condyle.

In the collections of the National

Museum there are fom- individuals (Nos. 4934, 4935, 6645, and 7725) which havethe atlas preserved. The first three have the neuracentra detached from theiatercentrum, but the latter, from which figure 13 was drawn, shows these pieces
firmly coossified. Although the upper part of these arches is incomplete (havingAbeen restored from the other specimens) this specimen gives amost accurate idea of the mannerof the articulation of these lateral,pieces in the atlas of Stegosaurus,
as is clearly shown in figuire 13,

A.

Just above the neck-like con-traction of the pedicel the neu-

racentrum gives off two processes,
one directed inward and upward,
which with the corresponding
process of the opposite side forms
the covering of the upper part of
op Stegosaukus stenops ? Maesh. Cat. no. 6645,
Nat. size. A, Viewed from left side; in, intekCENTKTJM,- n, ffEUEACENTKUM,- S, NETOIAL SPINE; z', POSTEEIOEZYGAPOPHTSIS; EESTOEED FROM THE ATLAS OF NO. 4935, U.S.N. M.
B, VIEWED FROM THE FRONT; B, CDP OR ARTICULATING SXIRFACEFOR THE OCCIPITAL CONDYLE OF THE SKULL; S, NEURAL PROCESSES.
C, Viewed from the back; p, broken surfaces whence postZTGAPHTSIAL PROCESS IS GIVEN OFF; T FACETS FOR CERVICAL EIBS.

Fig. 13.— Atlas

U.S.N.Mi,

and is directed upward and backward,

its

the neural canal. The neuracentra did not unite on the medianline but were

probably bound to-gether by ligaments. The postzygapophysial process is more
slender than the one just described

lower internal surface being adapted

for articulation with the prezygapophysis of the axis.

The odontoid is a small bone (fig. 14, o), the upper surface, which is sMgbtly
concave transversely, forming the floor of the neural canal. The whole lower
part of the bone is rounded transversely. When articulated the anterior part isin contact with the upper concave surface of the intercentrum of the atlas. In
position the smooth anterior end abuts against the posterior end of the occipital
condyle.

The posterior end is slightly concave and is closely applied and in someinstances (see axis of No. 4935, fig. 14) is partly coossified with the centrum of theaxis.

Measurements of atlases.
No. 4934. No. 4935. No. 6645.

mm.
22

24

24

55

61

61

.

OSTEOLOGY OF THE ARMOKED DINOSAUEIA.

47—

The description to follow is based almost entirely upon the axis of
Axis.
specimen No. 4935. Althoiigii present in No. 4934, it is so badly crushed as to beof little value in determining the characteristics of the bone.
The centrum is plano-concave, constricted medially, with rounded ventral
surface without keel. In transvei-se diameter the enda are expanded, the anterior
extremity exceeding the posterior, but unhke the axis of Cam,ptosaurus the transveree diameter of the anterior end is less than the total length of the centrum.
The neural ai-ch is composed of two thin parallel plates of bone, which curvein above the neural canal, forming a sharp median longitudinal ridge or crest that
Tlie posterior portion flares out into an expanded
rises rapidly toward the back.
Well developedrufT-hke process which overhangs the centrum of the next vertebra.
posterior zygapophyses are present on the lower borders of the overhanging portion
The anterior zygapophyses are(fig. 14, z').
missing from this specimen, but judging fromthose of the atlas they must have been small
kw;,
and placed forward and well up on the side of
the arch.

The articular surfaces for the second ceron the anterior superior
part of the centrum and in the center of theneural arch just above tiie neuro-central suThe diapophyses extend outward andture.
A (,«,
f 7
r
^ A\
llg.
aownward
14).
vical rib are situated,

The neural canal is exceptionally
,

^T

.

1

subeUiptJcal
vertical.

large,,T
with the longer axis
m outlme,
J.U

-iT.

1

•

^''

—

"'^^^
rOKTION OF ATLAS OF''^'™
Stegosaukus sp. Cat.no.4935,U.S.N.M. Side
view, j nat. size, a, diapophysis; o, odon-^'°' '''

TOin; p, PAEAPOPHYSIS;z', P0STZTQAP0PHTSI3.

Neither of the two axes in the National Museum collections show anj'

indication of the presence of a second intercentrum as found ^ in Camptosaurus.
The odontoid, shown in figure 14, o, is only attached to the axis by matrix,

though it may become ankylosed in old indi^^duals, a condition observed by Nopcsa in Stegosaurus priscus.
Measurements of axis ' of No. 4935, U.S.N.M.
71

Greatest length of centrum
Greatest width anterior extremity

64Greatest width posterior extremity
Greatest height over all

54
llt>

Cerincals posterior to the axis.
first six vertebrae were found—Of the cervicalseries in specimen No. 4934 thearticulated as shown in text figure 16, and in plates 2

Nos. 8, 9, and 10 (see pi. 3), while not connected were so little disarranged
that there can be no question but that they represent a continuous series. AH ofthese vertebrae have suffered from crushing, particularly the posterior members of
the series, which have the processes so damaged that it is impossible at times toand 3.

determine their characteristics.
The cervical centra are all without pneumatic or medullary cavities and thesame remark applies to the entire vertebral series. The centra increase in length
2

C. W. Gilmore, Proc. U. S. Nat. Mus., vol. 32, 1907, p. 164.
F. Baron Nopcsa, Geol. Mag., vol. 8, 1911, pp. 110-111, fig. 1 (a).

'Measurements of the axis of No. 4934 will be found in table on page 5:i

1

UNITED STATES NATIONAL MUSEUM.

48

from the first to the fifth, the latter equaling the length of the twentieth of tlie
and in this diameter exceeding all others.
The first two or three centra might be called platycoelian, though they soon
pass into the biconcave type, which continues throughout the dorsal series. The
median cervicals have a much deeper concave
posterior end than the anterior end, but back of theeighth the concavities of these ends become about

series,subequal.

Viewed fiom below the ends are expanded, the
sides

of

the centra arepinched together, thus

making them concave longitudinally, with a strong
angular keel which widens at either end (fig. 16),
Fig. 15.— Median cervicalvertebra of more especially the anterior, which is roughened
Stegosaurus ungulatus Marsh. J Nat.
by coarse longitudinal striae. Proceeding toward
SIZE, a. Side view,i. Same vertebra,
B, NEURAL
d, DiAPOPHYsts;
CANAL; p, PAEAPOPHTSIS; S, NEURAL SPINE; ^,ANTEEIOE ZYGAPOPHYSIS; z', POSTERIOR ZYGA-FRONT VIET,

popHYsis.

After Marsh.

i^Q dorsols thc kecl bccomcs progressively
less
o
j ,
and ICSS COUSpiCUOUS.
^]j ^f .j^j^g cervicals have capitular f acets on thei.

.

and 17,^. Well-developed diapophyses extend outward from the sides of the neurapophyses. These haveheavy, expanded, articular ends, which look more downward than outward. The
diapophyses gradually increase in length proceeding posteriorly. On the side of
the centra near the posterior end, on a level with the parapophyses,is a roughenedsides near the anterior end, as shown in figures 15

Fig. 16.— Articulated cervical vertebrae of Stegosaurus stenops Marsh. Cat. no. 4934, U.S.N.M. Type. J Nat.
to six;size. Inferior view, a, Atlas; ax, axis; b, articular facet for cervical ribs;c3,c<,c5,c«, cervicals three
PjPakapophyses; r', left cervical rib to atlas; r", left cervical rib to axis; r, articulated cervical ribs belong-

ing TO the fifth and sixth cervical vertebrae; z', posterior zygapophyses.

protuberance wiiich probably indicates the point of insertion of ligaments.
*
These projections are especially pronounced on the cervicals of the posterior liaM
The neural canal remains large throughout the cervicals, changing
of the neck.
from a pear-shaped outline in the anterior ones to nearly circular openings in theposterior members

49

OSTEOLOGY OF THE AKMOKED DINOSAUKIA.

The prezygapophyses are wide apart and considerably raised above thediapophyses in the anterior vertebrae, but brought more to their level in the posteriorcervicals.

Neural spines

are not

present, except in themostalthoughthere is a weak, median, crestlike ridge, which eventuallydevelops into a true spinous
On account of theprocess.
damaged condition of theseprocesses I am unable todetermine the first vertebrae
posterior cervicals,

having such a process.
Dors ally the neural archa broad, trans-consistsofverselyrounded surface

which extends upward andcervical teetebka op Stegosaukus totgulatus?
Maksh. Cat. no. 7348, U.S.N.M. }N,it. size. 1, Side view. 2, Obuquefront view, i, diapophtsis; 11, neural canal; p, parapophysis; s, neuRAL spine: Z, ANTERIOR ZTGAPOPHYSIS; Z', POSTERIOR ZTGAPOPHYSIS.

Fig. 17.— Postekior

backward, the posterior
termination giving off the divergent branches of the post-zygapophyses. The
height of the arch gradually increases posteriorly.
Dorsal vertebrae {T^xQs&.Q,va\.s 11 to 26).' The dorsal vertebrae of Stegosaurus arecharacterized by the great height of the neural arch and the upward thrust of theThetransverse
processes.

—

centra of the posterior half ofthe vertebral column are transversely compressed, being shal-

lowly

concaveantero-poste-

riorly andsomewhat flattened

vertically.

All of the vertebrae

are without

lateralcavities.

In the anterior dorsals thedepth of the concave articular
ends of the centra exceeds thatof the posterior ends, but posterior

tothe mediandorsalregion the two ends are sub-equal in this respect.
In the table of measurements on page 53 it will be
FIG. 18.-ANTERI0R DORSAL VERTEBRA OP
obscrvcd that the ccutra gradU.S.N.M. i Nat. SIZE. 1, Side view. f^^^^^^'^^^^'-^^l^^^^-.
n, NEITRAL canal; P, PAR.AP0PSYSI3; S, NEURAL SPINE; z, ANTERIOR
ually incrcaso in length fromZTGAPOPHYSIS.
POSTERIORZTGAPOPHYSIS; z',
the thirteenth to the twentieth,
the latter being the longest of the entire vertebral series in No. 4934.
point posteriorly they gradually decrease in length to the sacrum.

From thisthe skull toward the sacrum, and
1 All through the text and legends to the illustrations, the presacrals are numbered fromnot from the sacrum forward as is the usual procedure in referring to the vertebrae as presacrals.

—

50

UNITED STATES NATIONAL MUSEUM.

There is not a sudden development of the spinous process as in Carrvptosaurus,
but rather a gradual growth, beginning with the sharp median ridge on the cervicals
and changing gradually into a distinct spine This change takes place at a point
anterior to the transition of the parapophyses from the centrum to the side of theneural arch.

Although the type of S. stenops has the complete presacral series preserved,
the exact point where the change from cervical to dorsal takes place can not be
conclusively demonstrated. This transition part of the backbone has been badly
damaged by crushing, and it is impossible to determine many of the principal
vertebralcharacters.

Theeleventh vertebra(counting from the skull)shows plainly that theparapophysis is on thecentrum.
On the fifteenth it is found on theside of the neural archat the base of the lamina
which rises to ^pport theunder side of the transverse process.

The posi-

tion of the parapophyseson the three intermediate
vertebrae can not be detected,

but one thing iscertain, the transition ofthis facet occurs between

the eleventh and fifteenthvertebraeand probably

takes place on either the
Antekioe doesal teetebea of Stegosatjeus sp. Second vektebea
POSTEEIOR TO ONE SHOWN IN FIG. 18. CAT. NO. 6531, U.S.N.M.
NAT. SIZE.
i, Diapophtsis; n, neueal canal; p, paeapo1, Side view.
2, Feont view,
PHYSis; s, neueal spine; z, anteeioe zygapophysis; z' , posteeioe zygapophysis.

Fig. 19.

J-

tweKth or thirteenth.

The vertical elongation of the neural arch is asomewhat rapid change,
beginning with the posterior cervicals and continuing into the anterior dorsal region(figs. 18 and 19).
These vertebrae were found articulated, there being one vertebra
between them. In S. stenops (No. 4934) the maximum height of the dorsals isreached on the twentieth vertebra from the skuU. A selection from the vertebral
series of one skeleton is given in figui-es 18, 19, and 20.
The neural canal in figure 18 shows the brachial enlargement, and in the moreposterior vertebrae, figures 19 and 20, its decreased size. Unlike S. ungulatus (fig.
21), where the neural canal is higher than wide, in this specimen it is subcircularin outhne.
The spines gradually increase in height and also in the antero-posterior diameter
proceeding posteriorly to the mid-dorsal region. From this point back to the

OSTEOLOGY OF THE ARMORED DINOSAURIA.

51

sacrum the neural processes are of about equal dimensions. The summits of all
are moderately expanded transversely.
A deep cupped capitular facet is present on all of the vertebrae posteiior to thefifteenth, and its position on the side of the arch at the base of the transverse process
remains practically unchanged, except on two or more of the posterior dorsals,
where it is produced outward on a thick buttress of bone (fig. 20, 1), but to a lessdegree than in the posterior dorsals of either Camptosaurus or Triceratops, where it
is foundmore on the anterior border of the transverse process.

Fig. 20.— Postebiok dorsal vektebea of Stegosaubus sp.

Cat. no. 6531, U.S.N.M.

i Nat.

Front VIEW. 2, Side view, d, Diapophysis; n, ned-ral canal; p, paeapophysis;
2', POSTEEIOE ZYGAPOPHYSIS.
S, NEUBAL spine; Z, ANTEEIOE ZYQAPOPHYSIS;

SIZE.

1,

The transverse processes are comparatively stout, subtriangular in cross-section,
and are rather unique in their great upward inclination from the horizontal, whichin the anterior and mid-dorsal region rise to nearly the height of the neural spine.
This inclination of the transverse processes of the anterior and mid-dorsal regions
approach the sacrum they become
is nearly 50° above the horizontal, but as wesomewhat more depressed.
The elevation of these processes is considered by Lull " a wonderful adaptationback is adorned."for bearing the great dermal plates with which the''Amer. Joum. Sci., vol. 30, 1910, p. 367.

—.

UNITED STATES NATIONAL MUSEUM.

52

Nopcsa ^ concurs in this view when he says this upward inclination "is rather
due to the increasing weight of the double row of dorsal plates." To me the above
reasons do not seem to be the logical explanations for these modifications in thestegosaurian skeleton, particularly since there is no contact between the plates andthe vertebrae, and also since there is a very similar elevation of the transverse
processes in Trachodon, Triceratops, and even in the Sauropod dinosaur HaplocanthosauTUS, aU of which are considered to be imarmored animals.
The zygapophyses are large and obliquely placed, those in front looking upwardand inward, those behind looking downward and outward, as is well shown infigures 18, 19, 20, and 21. There is^no zygosphene articulation of the^vertebrae in Stegosaurus.

Thezygapophysial articulating
surfaces are elongated ovals, thediameterlongestverse.

being

trans-

They remain fairly constantin size throughout the series, butnarrow antero-posteriorly

in

the

posterior members of the vertebral

column.

Dorso-Sacral

27){Presacral—The centrum ofNo.

this vertebra

and firmly cooEsified withboth the vertebrae in front and
Likewise theback.
(s(Z.,fig. 23.)is short,

Fig. 21.

Doksal vektebka or Stegosaurus ungulatus Maesh.

spinous process is firmly cojoinedd, Diapophysis;i Nat. size, a, Side view. 6, Fkont view,n, NEUKAL CANAL; p, PAEAPOPHTSIS; S, NEUEAL SPINE; Z, ANTEEIOR

with those of the sacrals.
This vertebra Ues distinctly in
ZYGAPOPHYSIS; Z\ POSTERIOR ZYGAPOPHYSIS. AFTER MARSH.
front of the neck of the ilium, andfrom the fact that it does not bear a sacral rib, and does have a short, stout dorsal
rib, even though that rib is partially metamorphosed, it can very properly be considered the last dorsal (Z', fig. 22, and sd, fig. 23).

The rib mentioned above is plainly shown on the right side of specimen No. 4934
The head is firmly coosified with the diapophysis, the shaft being directed
forward and outward to the ilium, with which, in conjunction with a strong upward{y, fig. 23) .

and forwardly directed process from the first sacral rib, it gives strong support. A
narrow transverse slit separates the rib from the outwardly directed bar of the firstsacral, although in aged individuals these borders would doubtless be joined.
The transverse process, unUke those of the dorsals more anteriorly, is muchdepressed, coming out nearly at right angles to the neural spine.
1Geol. Mag., vol. 8, No. 3, 1911, pp. 112-113.

OSTEOLOGY OF THE AEMOEED DINOSAUKIA.
Measurements of sacral and presacral vertebrae of Stegosaurus stenops.

53
No. 4934.

Type.

Greatest
Greatest
length or

Vertebrae.

centra.

trans-

diameterposterior
ends.

Greatestheightover all.

mm.

vim.
Atlas

32

Axis

56

3

66

4

82

5

6

:

61

104

67

96

80

7

99

8

93

9

84

10

87

H

73

12

74

13

56

135

70

14

75

15

82

16

85

17
18
19

lOle

20

105

21

102

68

22

101

76

23

102

24

97

86

25

85

104

70

76

26

430
468
430

69

27 Dorso-sacral
Sacrals:
I

72

II

69

Ill

75

102

Sacro-caudal

78

116

/Sacrum.—The following description of the Stegosaurus sacrum is based upon
the sacra of five individuals in the National Museum, but more especiallyupon thewell preserved articulated pelvic arch pertaining to the type of S stenovs
No 4934
(fig.

'

23).

'

In the sacral region of this specimen there are five coossified vertebrae
but forreasons to be given later three only are considered as pertaining to
the true or
primary sacrum. In describing the sacrum of S. ungulatus Marsh found
six vertebrae coalesced, four of which he considered as true sacrals (fig. 22). In
specimen
No. 7346 there are three coossified centra,
Nos. 6531 and 7386 there are four each,and in No. 4936 there are six. From this evidence it would appear that in
fully
adult animals the pelvic arch may be strengthened by the addition of one
or more'm

I

51873°— Bull. 89—14

Amer. Joum. Sci., vol. 21, pt. 4,5,

p. 168, fig. 1, pi. 7.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

54

presacral vertebrae and in one species at least (S. ungulatus) by the addition of ananterior caudal.

In No. 4934 the first coossified vertebra bears a free rib (see X, fig. 23) which was
found still articulated with it, and this vertebra can, therefore, be referred to the preThe next one posteriorly is firmly cojoined to the sacrals by the neuralsacral series.
spine and the shortened rib has become firmly coalesced with the diapophyses. This
inner end of the rib abuts against the ilium and unites with a process from the first
Since thissacral rib, together forming a considerable support to the ilium (y, fig. 23)vertebra does not supporta sacral rib it may very
appropriately be called adorso-sacral.
In the sacrum of this specimen
there remain but threecoossified elements thatmay properly be considered as being true sacral.

The last ver-yertebrae.

tebra, which corresponds

to the fourth sacral in S.
ungulatus (compare fig.

22 withfig.

23), has aprocess which articulateswith the ilium, and isregarded as a modified
caudal which will here becalled caudo-sacral.

The

centrum is detached fromthe third or last sacral

and the spine is also free.
The sacral centra,
like all others in the ver-tebral colunm, are solid,
Fig. 22.— SiCEUM and illv of Stegosaurus ungulatus MAEsn seen peom below.

oCjACEtabulaesueface; 6,eiboffiest
SACEAL veetebra; C, EIB of last saceal VEETEBEA; il, ilium; 1, SECOND DOESALFROM SACEUM OE PRESACRAL NO. 26 COUNTING BACK FROM THE SKULL; I', LASTDOESAL OR 27th PRESACRAL; p, LAST SACRAL VERTEBRA. AFTER MaKSH.
i'jNat.size.

a, First saceal veetebra;

and they graduallyin-crease in size from front

In S. ungulatus,
they are depressed vertically, and transversely have broadly rounded ventral surfaces, without pronounced
ventral keel. In S. stenops, however, the centra are not depressed, and there is a
decided ventral keel. Each centrum supports its own parapophysis (sacral rib),
although there is a tendency to overlap the preceding centnmi.
The ribs are stout, Avith expanded proximal and distal ends. In adult specimens
the proximal end is firmly ankylosed with the centra and the distal ends coalesce
to form what has been called the sacricostal ^ yoke which articulates with the ilium.
1

to back.

E. S. Riggs, Field Columbian Museum, Geol. Series, vol. 2, No. 4, 1903, p. 179.

OSTEOLOGY OF THE AKMOEED DINOSAUEIA.

55

In S. ungulatus and S. armatus, No. 4936, as shown in figure 22, theends of fourribs unite to form this yoke, while in S. stenops only threeparticipate in its formation.

Marsh laid considerable stress on the manner of the articulation of the sacralribswith their respective centra, and even went so far as to establish * thespecies 8.

duplex largely on these differences.

He says:In the sacrum of tliis species each vertebra supports its own transverse

process or rib as in the SauroS. ungulalus the sacral ribs have sliifted somewhat forward, so thatthey touch, also, thevertebra in front, thus showing an approach to some of the Omithopoda.

poda, Willie

Fig.

m

23.— Pelvic

region of Steggsadeus stenops Mabsh. Cat. no. 4S34, U.S.N.M. Type
About -^ n\t size
Ventral vieav snow as found in situ. A, Acetabulum; Co, fifth caudal; c.r,
caudal eib; cs, caudo-saceal'D, dorsal vertebra, or presacral no. 23; F. left femur; F', eight femue;
11, ilia; Is, left ischium- /y rightischium; P, left pubis; F', eight pubis; r, Rins of left side;r', Ems or eight shje; st, sf, sS, sacral vertebrae
one, two, and three; si, dorso-sacral or presacral no.
27; X, last free rib articulated with prfsace\lNO. 20; y, BUTTKESS from the FffiST SACRAL WHICH ABUTS AGAINST II.a'M.
THE BEAD OF THE RIGHT FEMUK \ND
portion OF THE RIGHT PUBIS ARE REMOVED TO BETTER SHOW THE SACRALVERTEBRAE.

After comparing Marsh's drawing of the sacrum of S. ungulatus (fig.
22) with thesacra
the National Museum the actual dift'erences in this respect are so slightmitappears to be entirely one of degree which may readily be accounted

ground of relative age.
Amer. Joum. Sci., vol. 34, pt. 9, 1S87, p. 416.

for on the

UNITED STATES NATIONAL MUSEUM.

56

The upper surfaces of the diapophyses of the sacrals have an unusual development antero-posteriorly in Stegosaunis inasmuch as they coalesce into a continuous
sheet of bone which roofs over the entire area between the spinous processes andthe ilium with which then- outer ends articulate and in adults are usually foundThis roof of bone is on a level with the superior flattened surface
The diapophyses of all the sacral vertebrae send downward thinfirmly coossified.
of the ilium.

vertical lamina that unite suturallywith the upper border of the sacral
ribs oftheirrespective vertebrae,thus forming bony partitions wliich
separate the large sacral foramina.
Internally these foramina arebounded by the sacral centra andexternally by the expanded coalesced distal extremities of the sacral
ribs, together with the internalsurfaces of the ilia.
Unlike the
Sauropoda, there appear to be no
openings leading through these partitions

from one foramen to theother.

The neural spines of all the vertebrae giving support to the pelvic
arch are comparatively short, withexpanded summits. Then" height
above the level of the ilium in S.
stenops is fully one-fourth less thanin S. ungulatus, as figured by Marsh.

The spines of the dorso-sacral andthi-ee sacral vertebrae are coalesced

and form an elongated bony plate,there being a single elongated aperFig. 24.— Cast of

neubal cavity in sackum of Stegosaxteus
ALL FIGS. J NAT. SIZE. 1, SiDE VIEW. 2,

TJNGULATUS MaRSH.
Seen fkom above.

3, Outlines repkesentestg transverse sections THROUGH BRAIN AND SACRAL CAVITIES, a, ANTERIOR END:

BR.VIN; e,e,e,TOR\iUNA between sacral vertebrae; p^exit
OF neural canal in last sacral vertebra; s, sacral c.avitt.

6,

All after Marsh.

ture between the spines of Sj and S3(pi. 4).

In S. ungulatus the spinesof the three sacrals are apparently

the only ones to thus become conThe direction of the spines
is almost straight upward, there

joined.

being a slight inclination backward in the spine of the last sacral.
The unusual development of the neural canal is well shown in plate 19, lower figTirec. of specimen No. 7386.
This large cavity appears to lie whoUy within the neuralprocesses of the sacrals, and in this specimen has a greatest transverse diameter of 1 23mm. The internal surface is comparatively smooth with the widest and deepest point
toward the anterior end. The large exits for the nerves leave the chamber throughvertically elongated openings leading into the sacral foramina (see fig. 24, e, e, e).

:

:

57

OSTEOLOGY OF THE ARMOKED DINOSAURIA.

These lie below the level of the diapophyses and between the lower portions of theneural arches.
In describing the nervous system of S. ungulatus, L\ill ^ makes the followinginteresting comments on the enlarged neural cavity in the sacrum

Tte neural canal in the sacrum is of startling dimensions, having a maximum enlargement of 1.14
more

cm. and a greatest width of 0.95 cm. and displaces nearly 1,200 cc. of water, thus giving it a mass
than 20 times that of the brain.
The brachial enlargement was the seat of innervation of the powerful fore limbs, while that of thesacrum was mainly the reflex and coordinating center for the control of the mighty muscles of the hindlimbs, but more especially of the powerful, active, and aggi-essive tail, which constituted theprincipal

means of defense.

Marsh says
It is an interesting fact that in young individuals of Stegosaurus the sacral cavity is

proportionately

larger than in adults, which con-esponds to a well-known law of brain growth.

Measurements of sacral vertebrae of Stegosaurus stenops, No. 4934-

mm.
215

Total length of three sacral centra
Greatest expanse of transverse process of first sacralGreatest expanse of transverse process of last sacral
Height of neural spine above zygapophyses, about

Length of coossified spines (4 vertebrae)

255
155

312
272

Total lengtli of 5 coossified centra

Gaudo-sacral (cs.).

145-—In specimen No. 4934 the vertebra designatedas the firstor caudo-sacral is analogous to the vertebra in the S. ungulatus sacrum which Marshconsidered the last or fourth sacral (fig. 22). That it is a modified caudal appears
to be indicated by the low arch; the strong backward slant of the spinous process

which is separate from the coossified processes of the sacrals, the noncoossificationof the centrum with the sacrum, and the distinctness and manner of articulation of
the rib with the ilium.
The rib of the caudo-sacral apparently has an origin similar to those of the
It is extended cUstaUy, forming a vertical plate of bone with expanded
true sacrals.
The inner or proximal end unites by suture with the side of the arch and theends.

body of the centrum, while the outer or distal end abuts against the inner, posterosuperior border of the ihum, posterior to the inner end of the articular surface forthe ischium. The proximal articular end is confined entirely to the centrum of
the vertebra and does not meet the rib of the last sacral as in S. ungulatus. Like-

wise the distal end does not, and never could, in this specimen at least, enter into
the formation of the sacricostal yoke. This end is entirely distinct from those of thetrue sacrals and its lower border is considerably above the acetabular border, whereas
in S. ungulatus (fig. 22), it is firmly coossified with the rib of sacral three and withthe other ribs of the sacrum enters subequally into the formation of the yoke.

(Compare figs. 22 and 23.)
The centrum of this vertebra in S. stenops is distinguished by its broadly roundedinferior surface, as compared with the keeled centra of the sacrals and the blunt
wedge-shaped centra of the succeeding caudals when viewed from the side.
>.\mer. .Toum. Sci., vol. 30, 1910, p. 372, ftg. 9.

58

BULLETIN 89, UNITJBD STATES NATIONAL MUSEUM.
Caudal vertebrae.

—Tn the palooiitological colloctionof the National

Museumthero are no less tliaii 7 articulated scries of caudal vertebrae, in addition to a great

number of detached elements.

Although noneof these series represent a complete tail, they atleast supplement one another to such an extent

that a very correct idea can be obtained of theentire caudal I'egion of Stegosaurus.

With specimen No. 4934

there

are 22 cau-dals preserved, 17 being articulated with the

The romaiiiing 5 are disarranged, but

sacrum.

represent the next of the series.
Specimen No. 4714 has 44 vertebrae in series
beginning with the fourth and continuing to thevery tip (see fig. 58). A smaller individual. No.
6531, has 40 caudals present, and it appears that
doubtless

are

more
miss-

ing

from

4 or

the prox-

imal andFig. 25.— SECON])? CAUIIAI,

VERTlCliUA

ui'

Steuo-

sAUEus VNOiiLATUS Marsh. Jnat.size. Fkont
VIEW. ;), Tkansveese PBOCEss;
NEUKAL spine;
APTER MAKSIL
2, ANTERIOR ZYOAPOPHYSIS.
.s',

1

"'
'

an equal,, ,yi ],
H UOX

,1

f,

from

•,.

the

distal end of the series.
Tlie oth(>r specimens
have from 22 to 27 vert(*brae preserved, allrepresenting the distal half oftlie tail, ai\d inmost instances coutiivuing to the tip.

After acareful study of sdl tliese specimens, it app(>arsthat there are at least 45 vertebrae in the complete caudal series of Stegosaurus, and in someindi'vaduals as many as 48 or 49 may bo found.
Marsh, in his restoration of Stegosaurus, shows
the series as consisting of 46 vertebrae.
The centra throughout the tail are shortand remarkably uniform in length (see table ofmeasurements, pp. 60 and 61) when comparedwith the caudal series of most other dinosaurs.

The centra o1' the anterior half ofthe tail arebroader than long, but these proportions are v la. 2(5.— .\NTEKIOR CAUDAL VERTEBRA, PROBABLY
revelled in the posterior half, wliere the verte- THE POURTIl, 07 STEGOSAURUS UNGULATUS MARSH.
Cat. no. Ol)40, U.S.N.M. About \ nat. size. Side
brae are more compressed transversely. .i\ll of viKW. c. Caudal kik or transverse process; s,simne; j, anterior zygapophysis; z', posterior
the caudals are constricted medially.
ZYG apophysis.
The caudal centra of Stegosaurus may be
distinguished from those of other American Jurassic dinosaui'S by their hexagonal
shape when viewed from the ends, as plainly indicated in figure 28.

—

OSTEOLOGY OF THE ARMORED DINOSAURIA.

59

The anterior caudals are the largest in the whole vertebral column, and have
exceptionally high, backwardly directed neural spines, the summits of which terminate
in heavy, transversely expanded, rugose heads, as shown in figures 25 and 26.
On
the anterior third of the tail these processes rapidly decrease in height posteriorly.

In spechnen No. 4934 the sixteenth

is only a little more than half the height
Posteriorly the spinous processes continue to decrease inheight and disappear altogether on the tliirty-sevcnth or thirty-eighth vertebrae.

of thefirst

caudal.

The transversely expanded summits become distinctly bifurcate in the midcaudal region, a condition prevailing as far bade as the twenty-fifth or twenty-sixth
caudal.
Posterior to tMs point the transverse expansion of the spine becomesgi-adually less and less until the last few vertebrae have a spine that consists of a thin,sliortcning plate of bone
without any expansion of the summit.
These also differ from those more anteriorly in that they do not overhang
the posterior ends of the centra (pis. 15
and 16). The remaining caudals havethe neural canal roofed over even to
gi-adually

the terminal one, as shown in plate 16.

Excepting the first or caudo-sacral,the nine succeeding vertebrae have vertically elongated transvci-se processes

which may be best described as resembling the "cleats" to which ropes are
made fast on board ship (figs. 25 andOn the second caudal they ap26).
pear as a thin vertical plate, springing
directly from the superior lateral sur-face of the centrum, the lower part

Anteriok caudal vertebra of STEGo.sAtmus unGULATUS MARSn.
rEOBABLY THE TENIII. J NAT. SIZE.
Side view, b. Front view, c, Face for chevron;n, NEURAL
canal; P, transverse process; 5, N3UBAL
spine; z, anterior zygapopiiysis; z', posterior zygapopnYsis. .\fter MiRsn.

Fig. 27a.

being produced into an irregularlyrounded process which extends outward, downward, and somewhat for-ward. Unlike the transverse of the caudo-sacral, it is not in contact with theilium, nor is this plate perforated as in some of the Sauropoda.
The third caudal
bears the heaviest and longest (vertically) transverse process of any posterior to theand in S. stenops it is also the first of the series to send a flattened projection
above the superior point of attachment to the centrum (see 6, fig. 27). This type ofprocess decreases rapidly in size, proceeding posteriorly, and in the eleventh caudal,
in No. 4934, it has changed to a short, blunt, triangular process which becomes
smaller and snaallcr and finally disappears altogether on either the sevententh or
first,

eighteenth vertebra.

The vertebrae are joined by closely fitting zygapophyses of moderate size. On
the anterior half of the tail tliey overhang at both ends, but posteriorly, especially on
the distal portion.

The anterior zygapopliyses are gradually prolonged anteriorly.

UNITED STATES NATIONAL MUSEUM.

60

the posterior zygapophyses being well within the posterior boundary of the centra.
The zygapophyses continue to wdthin three or four of
the tip, as shown in plate 16.

b

In placing the first chevron on the third caudal,
Marsh is probably correct, although I have no positive
evidence on this point. The most anterior caudals
In both No. 4714
are without distinct chevron facets.
and No. 6531 the sixth caudal is the first to show welldefined facets for chevron bones, although they were
found articulated in advance of this point.
Fig. 28.—Median caudal vertebra
In the median caudals the facets are placed on promPOSTERIOR TO THE 2GTH OF STEGOinent tubercles developed on the postero-inferior surface
UNGDLATUS MAESH. J
SAtTRUS
NAT. SIZE, a, Side view, b, Front(fig. 28), and although gradually diminishing in size,
VIEW. After Harsh.
In
are present on all except the last few at the tip.
specimen No. 4714 the third caudal from the distal end has a chevron still articulated, as shown in plate 16.
Measurements of caudal vertebrae ofStegosaurus.
No.

Greatest height of vertebrae,over all.

Greatest transverse diameter
posterior end of centra.

Greatest length of centra.

otverte-braein series.

No.

No.

No.

4288. 4714. 4934.

No.

No.

No.

No. No. No.

No.

No.

No.

No.

No.

No.

No. No.

No.

No.

No.

No.

6099. 6136. 6531. 6629.
)099. 6135. 6531. 6629. 4288. 4714. 4934. 6099. 6135. 6531. 6629. 4288. 4714. 4934.
1

mm. mm.

mm. mm. mm.

mm. mm. mm. mm.

mm. mm. mm. mm. mm. mm.

mm,.

2
137

46

77

57

66

65

62

52

92

58

65

49

98

98

7"

58

68

52

92

88

306

"

59

72

55

90

300

60

70

55

86

91

285

78

88

255

85

245

76

233

76

224

"

320

10.

61

66

56

u.

66

66

54

12.

64

65

54

13.

63

66

56

14.

66

63

66

68

72

15.

67

64

55

67

68

210

65

70

203

16.

65

63

17.

71

68

70

32

58

66

18.

61

71

68

54

58

64

53

19.

65

65

65

54

57

58

20.

66 60(?)

64

64

65

65

21.

64 60C?)

64

66

62

65

22.

61 70(?)

63

55

45

54

66

23.

62

61

53

44

52

59

64

24.

62

69

53

46

55

57

56

178
160

175

160

175

52

136

160
66

125

135

124

62

61

67

eo

51

46

43

56

48

61

61

61

51

46

48

65

65

47

120

48

66

60

67

50

45

46

61

45

115

50

47

109

52

45

64

60

57

49

44

48

49

55

56

49

43

48

60
53

126

143

27

45

146

163
58

26.

46

180

194

25.

29

262

210

56

28

265

116

150

88

OSTEOLOGY OF THE AHMOEED DINOSAXJEIA.

61—Continued.

Measurements of caudal vertebrae of Stegosaurus
No.

Greatest transverse diameter
posterior end of centra.

Greatest length of centra.

of
ver-

Greatest height of vertebrae,over all.

te-

brae
in series.

No. No. No. No. No. No. No, No. No. No. No.

No.

No. No. No.

No.

No.

No.

No.

No.

No.,

4288. 4714. 4934. 6099. 6135. 6531. 6629. 4288. 4714. 4934. 6099. 6133. 6531. 6629. 4288. 4714. 4934. 6099. 6135. 6531. 6629.

mm.

mm.

mm. mm. mm.

mm. mm. mm.

mm. mm.

mm. mm.

30.

42

48

53

S3

48

43

46

31.

42

45

48

61

48

42

43

50

48

32.

39

44

46

48

47

41

43

43

47

33.

35

41

45

48

44

39

38

34.

33

40

45

45

42

38

39

35.

32

38

41

40

40

36

36.

29

37

40

38

37

34

37.

29

36

36

36

35

34

38.

26

33

36

35

33

31

30

39.

27

33

36

32

33

30

31

40.

26

29

35

30

30

27

30

23

27

28

40

32

41.

23

29

30

26

29

24

25

28

26

26

36

28

42.

20

23

27

23

26

23

23

27

25

43.

18

18

25

22

24

22

19

21

24

21

24

44.

18

18

18

19

21

19

16

16

22

19

21

19

45.

16

18

18

21

19

12

19

18

18

13

46.

14

18

17

11

12

18

11

47.

14

9-1-

16
8-1-

46

47

35

39

103

94
44
42

37

44

103

91

85
42

75

41

40

67

38

39

62

37

37

35

35

34

55

28

33

32

4S

25

29

31

73

60
49

33

30

29

25
25

94-

Chevrons.

The chevrons of Stegosaurus are noteworthy on account of the great transverse
width of their proximal ends, when compared to their short length. They havethe usual Y-shape, with expanded articular surfaces. In some individuals (fig. 29)
the chevrons of the anterior portion of the tail have these ends united medially bya bridge of b.one, thus entirely inclosing the hsemal canal. This condition, however, is variable, for in S. stenops, No. 4934, two chevrons, apparently the first andsecond of the series, have distinct articular ends. In other specimens one chevron
will be bridged and the next will show the articular surfaces separate (fig. 30).

The above conditions prevail only among the chevrons of the anterior half of thetail, for aU specimens agree in having those of the distal portion divided proximally.

The chevrons of the anterior half of the tail, when compared with those ofCamptosaurus, Iguanodon, and Trachodon, are short and stout, with especiallylarge haemal openings.
The free or distal end is expanded antero-posteriorly, andexcepting a few of the most anterior ones, has a decided backward sweep, whichbecomes more and more pronounced as the distal end of the tail is approached.
The successive changes that take place are well shown in figure 29.
The chevrons articidate intervertebraUy and, beginning with the third caudal,
continue, as shown in specimen No. 4714, to the next to the last vertebrae of theseries (pi. 16).

Marsh has indicated, in his restoration of the skeleton, that the first chevron
between the third and fourth caudals. In this he is probably correct, although
the evidence offered by specimens in the National Museum is not altogether conclusive.
As mentioned previously, there are no distinct chevron facets on the

is

62

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

anterior caudals, and in specimens Nos. 4714, 4934, and 6531, the sixth or seventh
centrum from the sacrum is the first to show facets. Two disarticulated chevrons
are retained in the rock just below caudals three and four in specimen No. 4934
(pi. 2), and as mentioned above evidently represent the first and second.
With
specinaen No. 4714, chevrons were also found in place in the matrix forward of the

Cat no. S.531, U.S.N. M. J NAT size, .i, Side view or cuevrons from anteeiok,
MEDIAE, AND POSTEKIOK PARTS OF THE TAIL. B, SAME, VIEWED POSTERIORLY.

Fig. 29.— Cheveons or Stegosauhus sp.

sixth of the series, so it is certainly known that chevi'on bones were present forwardof the caudals having well defined articulations.

The anterior chevi-ons of No. 4934 measure 160 and 156 mm. in length, andthose articulated with the fourteenth and fifteeaith caudals of this same series
measure, respectively, 119 and 109 mm. in length.

OSTEOLOGY OF THE AKMOKED DINOSAUEIA.

63

Ribs.

In Sfegosaurus there are present cervical, dorsal, sacral, and caudal ribs.
Excepting the atlas, all of the other presacral vertebrae bear double-headed ribs.
Cervical H5s.— With specimen No. 4934 there are eight cervical ribs present.
Four of these belonging to the left side were found articulated, as sho^vn in figure 16.
They pertain to atlas, axis, fifth, and sixth cervicals, respectively. The remaining
ribs are from the right side, and, excepting the one for the atlas, the others are
disarticulated.
There is one ci'ushed against the processes of the twelfth vertebra, counting back from theskull, but it can hardly belong to tliis vertebra.
The ribs of the atlas and axis are much damaged, but
enough of these bones are preserved to siiow that theirarrangement was very similar to that of the living crocodile.
They appear to verify the tentative arrangementof these bones in Diplodocus by Holland.^The ribs for the atlas are single headed and articulated with the facets on the lower posterior side of the Fig. 30.—
Cheveon of Stegosaueus ungulatus marsh. j nat.
intercentrum. This articular end has a width of 18 mm.
SIZE.
POSTEKIOK VIEAV.
a,
The rib for the axis articulates cliieliy with the paraFront view. Aftek Marsh.
pophysis and with tlie diapophysis by a cartilaginous
union, as in the crocodile. Both appear to have been long, tapering structures,
but of their exact shape little can be determined from the available specimi^ns.
The sixth rib (fig. 31) is a tri-radiate bone formed by the short and stout tubercular and capitular processes with a pointed posterior branch, which is triangularin cross-section.
Anteriorly the indentation between the articular process is moderately deep.
On the external side, directly below the tubercular process, theventral surface is produced outward, forming athin shelf of bone which curves slightly upwardand disappears toward the posterior end. This
shelf is not present on the 2:)osterior ribs of theneck as shown by specimen No. 7616. The posterior cervical ribs are longer and the articularll,

processes are lengthened, especially the tubercular.
Fig. 31.— Sdcth

CER\acA L KIB, left sniE OF
Stegosaueus sienops Marsh. Type. Cat.
NO. 4934, U.S.N.M. I NAT. SIZE.
Internal
VIEW, c, Capitulum; /, TUBERCULTJM.

The articxilar end of the capitular proc-

much lengthened
dorso-ventraUy, but compressed antero-posteriorly.
The sixth rib has a length of 95 mm.
Dorsal ribs. All of the dorsal vertebrae
ess in these posterior ribs is—bear double-headed ribs, and excepting those of the dorso-sacral all the othei-s are
free.
From a study of specimen No. 4934 it would appear that there were at least
15, and possibly one or two more, vertebrae carrying thoracic ribs, but of the exact
number I am now in doubt.
With the above skeleton there are portions of 25 ribs, most of wliich are practically entire.
Thirteen of these pertain to the left and the remainder to the right'Mem. Carnegie Mus., vol. 2, No. 6, 1909, pp. 249-250, figs. 2-22.

:

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

64

Tliose belonging to the left are retained in the matrix so nearly in theirside.

relative positions that they give a fairly correct idea of the changes that occur intheir length, shape,and other characteristics.

It appears that they represent theseries from the thirteenth vertebra back to the sacrum.

The fourteenth rib of thisside is missing, but is present on the opposite side and still articulated {X, fig. 23).

The ribs of this series increase in length and in other dimensions quite rapidly
from the first to the fifth, when they continue subequal in length to about the
Posterior to the ninth they shorten rapidly, at the same time becoming
ninth.
more slender throughout the head and shaft. Their gi-adation in length is weU
shown by the measurements of the following ribs:
760

Second of series, left side, gi-eatest length, about
Fifth, of series, left side, greatest length

1, 040Seventh of series, left side, greatest length about
Tenth of series, left side, greatest length about

1, 050885
385

Thirteenth of series, left side, greatest length about

The upper external surfaces of the anterior ribs are broad and flat, and posterior
produced posteriorly into a rather short blade, and anteriorly into a
Continuing posteriorly these projections become
subequal, so that a cross-section near the proximal end would be T-shaped, withto the fifth,

somewhat shorter projection.

the cross of the T formed by the external surface of the rib.

The lower half of the
LuU ' comments

rib is flattened and in cross-section would be an elongated oval.

on the T-shaped cross-section of the ribs in Stegosaurus as follows

A beautiful mechanical device is shown in that the transverse process is triangular and the rib
T-shaped in cross section in the armor-bearing region, giving the maximum of strength, a wide bearing
surface, and a minimum expenditure of material.
The significance of the above interpretation appears to be nullified somewhat
when it is known that almost identical conditions are found in Trachodon, an
unarmored reptile.^ Some of the Sauropoda also show a T-shaped cross section ofcertain ribs.
From this evidence, therefore, I can see no facts to bear out thetheory that this part of the internal skeleton was modified to support the dermal
armor. The inner surfaces of all the ribs are convex. The distal ends are neverThose of the median part of the series
spatulate, though sometimes thickened.
In the posterior part of the series the ends
are beveled off on the anterior margin.
are more truncate.

The tubercle and capitular facets are placed well apart throughout the entire
The tubercle rises but little above the proximal surface, wliile the capitular
process remains fairly constant in length and is given off nearly at right angles tothe shaft, so that when articulated with the vertebra it forms an extremely flat,lank body cavity. In this respect Stegosaurus bears a striking resemblance toDi-plodocus as depicted by Holland.^series.

1Amer. Joum. Sci., vol, 20, 1910, p. 209.

2

"The oblique T-shaped cross-section that has been specially noticed in Stegosaurus, but seems, as far as I am aware, to bepresent also in other members of the Orthopodous order. Its origin may therefore have to bo explained otherwise than throughthe weight oi the dermal armor." F. Baron Nopcsa, in Geol. Mag., vol. 8, 1911, p. 111.

—

3

Amer. Naturalist, vol. 44, 1910, fig. 17 (5).

OSTEOLOGY OF THE ARMOEED DINOSAUEIA.
Sternal bones.

65—^Aonong the puzzling elements found associated with the skele-remains of Stegosaurus in Quarry 13 were three bones (Nos. 7618, 7619, and7620) that are here regarded as representing sternal elements. They are of special
interest, as this is the first time ossified sternal bones have been found associatedtalwith Stegosaurian remains.
These plates are small, tiiangular, asymmetrical bones. As I interpret theseelements (fig. 32), after carefully comparing them with the articulated sternalsof Trachodon annectens (fig. 34), the broad titmcate end is anterior, the pointed
end posterior. The transverse width of the anterior end is over one-half thelongitudinal length of the bone. This end is truncated with a comparatively

Stegosaurus sp. Cat. no. 7620. U.S.N.M. J nat. size. 1, Ventral view, a, Anterior
end; r, r, roughened surfaces for attachment of cartilaginous biks. 2, Superior view, c, Point of cartilaginous UNION with opposite PLATE.

Fig. 32.— Left sternal boot:,

On the iimer side the anterior tliird presents athin but roughly rugose border.
thickened area winch looks upward and uiward and doubtless represents the medianunion of the plates of opposite sides. The ventral surface is slightly convex transBoth surfaces are comparaversely, and the dorsal or visceral surface is concave.
tively smooth -wdth the exception of roughened areas (r and r, fig. 32) which probably
represent the points of attachment of the sternal ribs. The outer border is somewhat thickened and romided, while the inner thins out to a sharp edge. Bothborders are shghtly concave from end to end.
Articulated, the broad truncated ends probably meet the anterior border ofthe coracoids, and the elements of opposite sides join on the median line at the thick-BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

66

ened rugose surface desci'ibed above.

ward and outward as in Trachodon

The pointed ends would be directed backAltliougb these bones were foundwidely separated in the quarry andnone of the three can be definitely associated with any of the surrounding
specimens, yet a comjjarison of theseelements with those of Trachodon (compare figs. 33 and 34) show such close
general resemblances that there ap-

34).

(fig.

pears to be but little doubt of theircorrect identification.

Among

the jjredentate

dinosaurs,

sternal elements were first discovered

showing probable manner op articulation OF STEGOSAUEUS sternal bones. J NAT. SIZE.
a. Anterior ends; p, postekioe ends; t, sternal eib.

Fig. 33.— Diagkam

by Marsh,
by Bro%vn,^ andThat they are present in all members

in Trachodon (Claosaurus)

Triceratops

later inquite recently by Gilmore ^ in Thescelosaurus.
of this group is likely.

Measurements of sternal bones.

No. 7618.

No. 7619.

No. 7620.

mm.
Greatest length

170

Greatest transverse width, proximal end

.

S(i

178

156

65

Shoulder Girdle.
Scapula.

—The scapulaiscomjjaratively short, and when not flattened by post-

mortem causes the inner surfaceisconcave from end to end, ren-dering it conformable to the con-vex curve of the body wall whenarticulated.

This

cuiwatureofthe scapula also tends to thi'ow
the articulated coracoid well infront on the chest, as in Thescelosaurus, Trachodon, Camptosaurus,

and Triceratops.
There are seven scapulae in
the National Museum collections
all showing a downward curve of
the bone proximo-cUs tally (pi. 21,

and not straight, as Marsh Fig. 34.— Left sternal bone of Trachodon annectens (Marsh).
has represented tliis element ini NAT. SIZE, a, Seen from above; 6, seen from below. After
M.ARSH.
In this respect
S. ungulatus.
they approach the scapula of Arvkylosaurus, as figured by Brown
fig. 3),1

2
3

Bull. Amer. Mus. Nat. Hist., vol. 22, 1906, pp. 297-300.

Smiths Misc. Coll., vol. 61, No. 2184, 1913, p. 4.
Bull. Amer. Mus. Nat. Hist., vol. 24, p. 196, fig. 15.

.

OSTEOLOGY OF THE ABMOKED DINOSAUKIA.

67

The upper portion of the blade is flattened; about equally expanded fore andaft; upper end cut off at nearly right angles to tbe sbaft,

with a slightly thickened
rugose border.
Passing toward the articular end the blade gradually contracts antero-posteriorly for two-thirds the length of the bone, wliile the tiansverse measurement gradTlie progressive thickenmg of the bone continues to the articular
endjwhich presents a heavy massive surface for the humerus (pi. 2 1, fig. S g). In specimen No. 7362 this end has .a transverse thickness of 100 mm. and is quite deeply
cupped. Approacliing the coracoid end the superior border turns upward at slightly
more than a right angle to the blad-e, as in the scapula of Diplodocus (see figure
by Hatcher'), forming a broad, thin expansion of tliis end. No acroiuian process

ually increases.

ispresent.

Two of the seven scapulae in the National Museum (Nos. 4934 and 7361) are
fii'mly coossified
size.

with the coracoid, forming with it a deep glenoid cavity of goodNo. 7361 measures 165 mm. across fi-om lip to lip, its greatest

Tliis fossa in

expanse.
Measurements of scapulae.

S. slenops

StegosauTUS sp.

Stegosawrua sp.

No. 4934,

No. 7362,

No. 7361,

left.

right.

right.

5. stenops.

S. sterwps.

No. 7371,

No. 4929,

left.

left.

mm.
Greatest

620

670

226

1215

685

7Bm.
67!)

687

192

215

110

135

breadth, proximal

Greatest breadth, distal end.

384

.

380
138

140

—

Coracoid.
The coracoitl is a subquadrate bone (pi. 20, fig. 1) which in very old
mdividuals becomes fu-mly coossified with the scapula. The superior portion of
the coracoid is thin, with convex external and concave internal surfaces. The lower
portion is much thickened, particularly that part contributing to the glenoid fossa,
which in No. 7376 measures 163 mm. in transverse width. The anterior portion of
the inferior border is considerably thickened and roughenerl fcu" ligamentary attachment.
The coracoid foramen is large and its elliptical internal opening is situated justanterior to the coraco-scapula suture, contmuing diagonally forward through the^

There are five coracoids in the colforamen to be entirely mclosed, and not a notch,
as figured by Mai-sh in his illustrations of this element of Stegosaurus ungulatus.

coracoid a little below the center of the bone.
lection, and all of them show this1Mem. Carnegie Mus., vol. 1, p. 44, fig. 14, 1901.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

68

Measurements of coracoids.
Stegosaurus sp.

No. 7362,

No. 7411,

right.

right.

Greatest length
Greatest height

Greatest transverse width of glenoid fossa

FoKB Limb and Foot.

The fore limb in Stegosaurus was very powerful, as is plainly evident from therobust size of the bones and the great development of the processes of the humerus
and lower limb bones. The large size of the olecranon process imphes a bent limbof the Ceratopsian type.
There were five digits m the fore foot, which was of goodsize and well adapted for supporting the great weight of this animal.
Humerus. The humerus is short and massive with widely expanded ends.
Below the center of the bone the shaft is greatly constricted and without meduUary
cavity.
The roughened radial crest is well developed and extends from the superior extremity down the antero-extemal border tliroughout one-haK the length of
the bone. The rounded rugose head is situated somewhat internal to the center of—the proximal end (pi. 20, fig. 2^.) and is produced backward, overhanging the posteriorborder of the shaft. The head passes on its inner side into an area roughened forthe attachment of muscles, which apparently is analogous to the lesser tuberosity
in mammalian humeri.
The greater tuberosity is apparently represented by arugose, strongly developed ridge of bone runnmg down from the proximal end on
the postero-external border.

The radial and ulnar condyles are weU differentiated and separated by a trochlea
depression of moderate width and breadth.
The anconeal and trochlear depressions are about siibequal, the former perhaps
being the better defined. The supmator ridge (pi. 20, fig. 2s.) is a prominent feature,
and adds much to the transverse expansion of the distal end. In adult individuals both proximal and distal articular ends are roughly rugose.
In the National Museum there are eight humeri. The principal measurementsof a number of these will be found in the table below.
In Stegosaurus stenops theratio in length of the humerus to the femur is 1 1 .9.
:

Ileasureme^its of humeri.
S. stenops.

Type, No. 4934.

Greatest breadth proximal end

No. 4929.

StegosauTUS sp.,

5. sulcatus,

S. urujula-type No.

No. 7409.

4937.

tun, No.
6646.

Left.

Eight.

Left.

Right.

Left.

Right.

Left.

mm.

mm.

mm.

mm.

572

530

506

612

452

304

303

315
227

202

278

103

102

lis

265
101

237

609

610

276

347
,

283
114

.

OSTEOLOGY OF THE AEMOEED DINOSAUKIA.

69

Ulna.— On the proximal end the ulna is expanded and massive, but from above
downward it tapers gradually to the very much smaller and little enlarged distal
end. There is a heavy olecranon process which is produced far above the articularsurface for the humerus (o., fig. 35). The surface of this process is roughened formuscular insertion. In S. sulcatus No. 4937 (pi. 20, fig. 3 ^), an exceptionally large
and aged individual, this rugose area is of triangular shape and extends
far down on the posterior side of the shaft.
In young individuals,
as shown by several specimens, the olecranon is truncate and rises
only a short distance above the articular surface of this end. (See3 B.)
In the great development of the olecranon process
the ulna of Stegosaurus resembles that of Triceratops, where, amongpi. 20, fig.

dinosaurs, it reaches its maximum development.

Viewed proximaUy the end is subtriangular in outline with a deeptransversely concave cavity on the front for the reception of the

When these elements are articulated,
the ulna completely hides the upper end of the radius from a posterior

rounded head of the radius.

view. On the inner or radial surface near the distal end is a flattenedrugose area, which in an articulated limb is opposed by a similar surface on the outer side of the radius.
These doubtless indicate thepoints of attachment for the ligaments that held these bones in place.

The distal end is comparatively smooth and rounded.

In outhne

35.— Left
ULNA OF ijTEGOIG.

UNGULATUS MAESH.
SAtnitrs,1

NAT. SIZE,

Side

view,

o,

ole ceano nwith an area less than that of the radius.
PEOCESS. AFTEEMarsh.
In specimen No. 4934 the ulna exceeds the humerus in length.
In adult animals it was found in nearly all instances that the ulna was equal to,
if it did not exceed, the humerus in this measurement.
In immature specimens,
however, on account of the shortness of the olecranon process the ulna is always
it is elliptical,

the shorter of the two bones.

(PI. 20,compare A and B, fig. 3.)

Measurements of ulnae.

S. stenops,

S. sulcatus,

type No.

type No.

4934.

4937.

540

Greatest width proximal end
Greatest width distal end

594
229
118

Least width o( shaft

61

Height of olecranon above humeral articulation

127—

Radius. The radius, although more slender than the ulna, is nevertheless ofrobust proportions. The shaft is constricted mediaUy, while the ends are expanded,

more especially the distal, which exceeds that of the ulna.

In uncrushed specimens

the shaft of the bone is a httle curved, with the convexity forward and inward.

The

proximal end is subelliptical in outline, with a slightly roughened concave surface.
51873°—Bull. 89—14

6

—

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

70

The posterior convex side of the head of the radius fits nicely into the radial grooveon the anterior face of the ulna. On the front of the shaft a shallow groove passes
diagonally downward across the front of the bone and doubtless marks the course
It is clearly shown in pi. 20, fig. 4 A. In immatureof one of the larger tendons.
specimens this groove is very indistinct.

The heavy expanded distal end is triangular in outhne with the apex of theThis end of the radius of specimen No. 4937 is divided

triangle directed outward.

into two unequal faces, which meet one another at an obtuse angle. The larger
one articulates with the radiale, but the smaller looks inward and backward andprobably represents the attachment of the heavy ligaments which bound the joints
This conclusion is further strengthened by comparing the surfaces of
together.
the two faces, the latter being roughly pitted and laclcing the finish of the former.
Measurements of radii.
S. stcnopSj

S.sulcatus,

type No.

type No.
4937.

Greatest length

Greatest widtli proximal end
Greatest width distal end

Least width of shaft

Forefoot.

,—A complete fore foot of Stegosaurusisas yetunknown, though aconsiderable number of supplementary specimens give a fairly good idea of its structure, but it yet remains to definitely determine the phalangial formula.

In young animals the proximal row of the carpus iscomposed of four bones, but in the adult three of these
consolidate to form a single element on the ulnar side.
The distal segment of the carpus remains unossified. The
digitigrade foot was large, and possessed five well-developed digits which were doubtless inclosed in a muscularmass, the only external evidence of the digits being theflattened hoof-like nails on the first and second toes.
Carpus. In Stegosaurus only the proximal row of the—Fig. 36.

Caepus of Stegosaukus

Juvenile.
Cat. no. 7403,
0.S.N.M. i NAT. SIZE. jIjFEONTAND B, TOP VIEWS, in. Intermedium; p, PISIEOEM; Mi,ULNAEE.
sp.

carpus is ossified. This row as now definitely determined
is composed of the radiale, intermedium, ulnare, and pisiform. It is only in young specimens that these elements
are found separate. In old animals the intermedium,ulnare, and pisiform become ankylosed to form a single element, and in adults where
the sutures have become obliterated the carpus would appear to consist of the two

block-like bones shown in figure 38, 2, uJ + in+p, and r.

In the collections of theUnited States National Museum, however, we are fortunate in having preserved insitu the radiale, intermedium, and ulnare of one individual (No. 7401, fig. 37) andthe intermedium, ulnare, and pisiform of a second specimen (No. 7403, fig. 36).

:

OSTEOLOGY OF THE ARMOKED DINOSAURIA..

71

Both pertain to small, partly grown animals.

These supplementary specimens show
very clearly the entire Stegosaums carpus, as may be seen by comparing figures
36 and 37.
Professor Mareh recognized three elements in the pi-oximal segment of the carpus and so indicated it in his restoration of
the skeleton.' Yet later in defining the genus
Diracodon^ he observes that " in the fore footthe intermedium and ulnar bones separate,
while in Stegosaums these carpals are firmly
coossified," evidently overlooking the factthat in plates 48 and 52 of the same article,
feet of the genus Stegosaums are shown withthese elements separate.

Radiale(jr.).

— The radialeismuch thelargest bone (see figs. 37 and 38, r) of the car-pus and is opposed distaUy by metacarpals
Proximally it articI, II, and partly by III.
ulates exclusively with the radius.
It is ablock-like bone, wider than long, with upperand lower articulating surf aces roughened, theformer being flat, the latter rather angxilarly

convex transverselj'.

The sides are verticalwith the exception of the posterior, which has
on its outer posteiior half a rounded depression of some depth. The principal dimensions of the radiale of an adult and a young
specimen are given below

Fig. 37.—Caepds (lacking pisifoem) and portion of

EIGHT FOEE FOOT OF STEGOSAUETJS SP. JUVENILE.
Cat. no. 7401, U.S.N.M. J nat. size. A, Front and »B, TOP VIEWS, in. Intermedium; r, radiale; ul,ulnaee; I, II, III, metacarpals one, two,
three.

andMeaswements of radiale.
Juvenile,

Adult, No.

No. 7401.

4937.

mm.

mm.

Greatest transverse diameter72

noGreatest antero-posterior diameter

62

103

Greatest vertical diameter

SO

70

Intermedium {in.).

—The intermedium

men bearing catalogue No. 7401.

will be described from the young speciViewed from above {in., fig. 37, B) this bone

triangular in outline, the front forming the longest side. The anterior face is
shaUowly concave doi-so-ventrally, with an arterial foramen notching the externalborder. In adult animals all traces of this notch are obliterated.
The upper rugose surface is regularly convex transversely. It articulates withthe radiale and ulnare by straight, vertical ends. In an articulated foot it is supported in part by both metacarpals III and IV. Above it meets about equally the
distal ends of the radius and ulna.
isIAmer. .Toum. Sci., vol. 21, 1881, pt. 4, p. 170.

>

Dinosaurs of North America,

72

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Measurements of intermedium.
Juvenile,

Adult, No.

No. 7401.

4937.

wm.

mm.

67

97

50

94

41

69

—

Ulnare (ul.). In specimen No. 7401 theulnareis smaller than the intermedium
and like that bone is triangular in outline when viewed from above (B, fig. 37, ul.).
It is thinner than the intermedium and articulates dorsally, exclusively with the
In specimen
ulna. Ventrally it probably opposed metacarpal IV and part of V.
No. 4937 the ulnare and intermedium are so closely ankylosed that the suture isalmost obliterated.
Measurements of ulnare.

Greatest transverse diameter
Greatest antero-posterior diameter
Greatest vertical diameter—

Pisiform (p.). As identified here the pisiform is an irregularly rounded bone,
the smallest element of the cai-pus. In the National Museum material specimen
No. 7403 is the only individual which shows this bone as a distinct element (fig.
In none of the adult specimens can
36, where it is shown as found in the quarry).
this suture be traced.

Measurements of carpus.
[Specimen No. 7403.]

Interme-dium.

Ulnare.

Pisiform.

mm.
28

81

52

69

52

33

57

41

24

—

Metacarpus. The metacarpus of Stegosaurus consists of five bones of about
Semi-articulated fore feet in the National
equal though robust proportions.
Museum collections supplement one another to such an extent that the position of
the metacarpals in the foot can be considered as absolutely determined. Specimen
No. 7401 (fig. 37) shows metacarpals I, II, and III of the right manus retained

nearly in their relative positions to one another as well as to the carpus, and No.
of the left foot.
4934 (fig. 40) shows the articulated metacarpals II, III, IV, and
The information fm-nished by these specimens indicates that the metacarpals

V

differ sufficiently from one another to be easily

recognized as to their proper posi(Seepl.21, fig.2.)

tion in the foot when found in a scattered and disarticulated state.

:

OSTEOLOGY OF THE AKMOEED DINOSATJRIA.

73

The following detailed description of these bones is based upon the foot oi
an adult specimen of Stegosaurus sulcatus, No. 4937, wliich is in a beautiful state ofpreservation

Metacarpal I (pi. 21, fig. 2, 1) is the shortest and stoutest element of the series andmay be distinguished at once by the great breadth of the shaft, being but little conThe ends are about evenly expanded, the proximal being subtriangular in outline with the rather blunt apex
directed inward. This end is roughened and slightly concave, with the outer borderbeveled off where it
meets metacarpal

stricted at the center when viewed from the front.

II.

The transverse

diameter of the distal end exceeds theverticaldiameter.

This end is convex
antero - posteriorly,

but concave transversely, thus form-

ing a broad groove
articulation
forwith the first phalanx of this digit.

The external

sur-face near the upper
end is concave antero-posteriorly androughened for the
better attachment
of

the

which

ligaments
the

bound

t o -

metacarpals
gether.

Metacarpal IIisand moretheslender thanlongerpreceding.

It

isRight foke foot of Stegosaurus sulcatus Maesh. Type. Cat. no. 4397,
U.S.N.M. 1 NAT. SIZE. 1, Front VIEW, in, Intermedium; r, radiale; ul, coalesced
INTERMEDIUM, ULN.IRE, AND PISIFORM; I, II, III, IV, V, DIGITS ONE TO FIVE. 2, PROXIMAL VIEW OF CARPAL BONES, SAME FOOT, r, RaDIALE; Ul+iw + fl, COALESCED ULNARE.
INTERMEDIUM, AND PISIFORM.

Fig

constricted medially, both in its lateral and vertical diameters.

From the front the ends appear to be about evenly expanded, but viewed
giving the bone
the proximal end is especially produced in a posterior direction,that of an equilaterala wedge-shaped appearance. The proximal end in outhne is(Seeantero-posteriorly.
triangle, the surface being roughened and sHghtly concave
laterallyII, fig. 39.)

The distal articular surface is broader than deep, bemg convex antero-posteriorly and broadly concave transversely.
Metacarpal III is the longest one of the five.

Its proximal end is about evenly

divided between the distal surfaces of the radiale and intermedium infoot.

an articulatedBULLETIN

7'4

UNITED STATES NATIONAL MUSEUM.

Viewed from the front the proximal and distal ends are about evenly expanded
transversely, but the proximal greatly exceeds the distal in the lateral aspect. The
constricted shaft of moderate breadthwhen seen from the front is produced
backward, the sides being pinched together, fonning a stout ridge wliichThe
joins the two ends of the bone.
posterior surface of this ridge especiallyat its center is rugosely roughened.
The distal end has two distinct arof articulated proximal extremities
OF metacarpals of bight mantjs of Stegosaurus sulcaMarsh.
Type.
Cat. no. 4937, U.S.N.M. J n'at. size.
Tus

Fig. 39.— Outline

ticular faces, which meet at

an obtuseangle on the distal end. The larger ofthese is shallowly concave transversely
and convex vertically for articulation with the first phalanx. This articular surface

does not round up on the anterior surface of the bone as in the preceding metacarpals, but the two surfaces meet sharply
at right angles. This feature will be discussed later in connectioii with metacarpals IV and V. The second surface

mentioned

above

outward

looks

and

downward and was probably opposed byan inwardly directed process from therV metacarpal as shown in 5, plate 21,
figure 2.

Metacarpal IV hasmuch the same

proportions as metacarpal II, except for
the heavier proximal end. The shaft isconstricted in both vertical and lateraldiameters.

The ends are expanded, more

especially the distal, and particularly on

the inner side of this end.

The articularface for the first phalanx is flattened andmeets the anterior surface of the shaft atright angles. This feature is even more
pronounced than in the preceding metaThese siu-f aces would appear to
carpal.
indicate the fiixed nat\u-e of the phalanges which opposed them, and, as will
be shown later, probably bore phalanges
which did not reach the outside of themuscular mass of the foot. As in metacarpal III,on theouter side

the

SHOWN AS found ARTICULATED. TYPE. CAT. NO. 4D34,
U.S.N.M.
NAT. SIZE. Palmar veew. r, Radule; rd,
DISTAL END OF RADIUS; U, DISTAL END OF ULNA; Ul,

surface

COALESCED INTERMEDIUM, ULNARE, AND PI.'^IFORM: II, V,
METACARPALS TWO AND FR^E.

of

distalend a second

looks

downward and outward and wasarticular

Fig. 40.— Left fore foot of Stegosaurus stenops Maesh>jprobably closely connected to an inwardly directed process from the distal end^of metacarpal V.

OSTEOLOGY OF THE AKMOKED DINOSAUKIA.

75

Metacarpal V (pi. 21, fig. 2) is the weakest element of this series, although
It may be recognized at once by thethis does not imply at all that it is vestigal.
straightness of its outer border and by the hook-Uke process developed on the internal

The shaft is moderately constricted; the(5, pi. 21, fig. 2).
rounded antero-posteriorly, widest on the external side, narrowing
toward the inner, as does the whole bone. The inner border of the proximal end is
The posterior side lacks the strong
slightly concave where it meets metacarpal IV.
metacarpals II,
ridge, with roughened surface, which is so prominent a feature in
III, and IV.
An outline drawing (fig. 39) of the proximal ends of the metacarpals showsthat when articulated their triangular ends combine to form a compact semiThere iscircular foot well adapted for supporting the great weight of the body.
no interlocking of the metacarpals as found in the feet of some dinosaurs, but thisside of the distal end
distal end isapparent mechanical wealmess is compensated for by the increased size of themuscles and Ugaments which bound the foot together, as indicated by the rugosity
In the shortness of the metacarpals, depth ofof the areas for their attachment.
to the footcarpus, and arch of the foot, there is a striking supei-ficial resemblanceof the elephant.

Phalanges.

—The phalangial formula yet remains to be determined. Of theproximal row of phalanges, only those pertaining to digits I, III, and IV have beenfound in place. In the left fore foot of specimen No. 4937 the first phalanx of digitin the foot of the same
I was found attached by matrix to the metacarpal, andand IV were foundside of S. stenofs, No. 4934, the first phalanges of digits III
similarly attached

(fig.

40).

This constitutes all of the definite evidence as to the correct placmg of thephalangial elements. With specimen No. 7401 (see fig. 37), a disarticulated foot,With thethere are sLx phalangial bones preserved, two of which are unguals.
termmal. Fourright fore foot of No. 4937 there are five phalanges, one of which isshown in figure 38.
of these have been regarded as constituting the proximal row as
The proximal phalanx of the first digit is undoubtedly the largest element of
this row.

It is wider than long, with posterior articular surface concave and anteBoth upper and lower surfaces concave lon-rior convex in the vertical direction.

gitudmally, the upper being convex, the lower concave transversely. The inner
Sde is longer than the outer, and when articulated makes it appear wedge-shapedwith the point directed toward the opposite foot.
In the half-grown animal the inner fourth of this bone is much depressed asshown by specimen No. 7401. The first phalanx of digit II is not certainly known.
The proximal phalanx of digits III and IV will be described from No. 4934
where they were found in place. They are short bones, wider than long, withconcave proximal, and convex distal articular ends. The palmar surfaces areends
flattened and produced posteriorly into a thin sheet which lies under theViewed superiorly the first phalanx ofof the metacarpals when articulated.
digit

IV presents a longer concave surface than the phalanx of digit III, but

the distal articulating surface is considerably reduced in size, and with a distinct
one of thearticular protuberance on the internal side of this surface, reminding—

BULLETIN

76

UNITED STATES NATIONAL MUSEUM.

homologous element in the Elephas foot. It probably represents the articulation
for the much reduced and last phalanx of this digit.
The principal measurements of these bones are as follows:

Digit III.

Digit IV,

Greatest transverse diameter
Greatest antero-posterior diameter.
Greatest depth of posterior face

Of the other phalanges found associated with disarticulated feet, they appear
intermediate in form and deserve no especial mention. The fore foot is provided
with at least two flattened unguals, and though as yet not found articulated, undoubtedly belong to digits I and II.

Dorsal view of unguals of Stegosaueus. 1, Ungual of hind foot. Cat. no. 7419, U.S.N. M. Juvenile
Ungu.il of digit I, forefoot. Cat. no. 4937, U.S.N.M, Type of Stegosaubus sulcatus Maksh. 3, Ungual ofCAT. NO. 7401, U.S.N.M. JUVTimLE. ALL FIGURES I N.AT. SIZE.

Fig. 41.
2,

DIGIT I, FORE foot.

These unguals are flattened, hoof-like bones that during the life of the animal
were doubtless incased in a horny nail. The specimens with which two unguals
have been found show that they are of two styles, one of which is as broad as long,the other more elongated. The relative shape and size of these unguals are wellshown in figure 41. From the position in the rock of the elements pertaining to
the right fore foot of No. 4934, I am led to believe that the elongated ungual (1,belongs to digit I.
In old individuals the surfaces of these bones become very much roughened,
and the lateral, posteriorly directed points shown in figure 41, 1 and 3, continue
to ossify until they project posterior to the articular end as blunt rounded points

fig. 41)(fig.

41, 2).

Belonging to the fore foot of No. 7401 are other elements which from theirclose resemblance to some of the reduced terminal phalanges of Eleplms are conAntero-posteriorly these are A^erysidered the final ones of the remaining digits.

OSTEOLOGY OF THE ABMOKED DINOSAXJEIA.
short, but long transversely;77

deep at the proximal end, with narrow and roundeddistal end..

It wiU be observed from the above description that the manus of Stegosaurus
entaxonic, as in Dvplodocus and Brontosaurus. Digits I and II were doubtlessprovided with a full complement of phalanges terminating with flattened unguals,
which in life were the only external evidence of their presence. In digits III, IV,
isand V the number of phalanges was probably successively more and more reduced,
each being terminated by a short transversely elongated functionless phalanx,that in hfe was entirely within the mass of the foot.
Measurements offore foot elements.

METACARPALS.
n.

I.

in.

IV.

V.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

7401.

4937.

7401.

4937.

7401.

4937.

7401.

4937.

7401.

4937.

mm.

mm.

61

91

84

106

82

128

.S4

mm.
HI

64

98

52

SO

49

70

53

78

56

SO

52

72

51

60

50

71

53

78

91

55

79

41

75

2S

43

28

40

45

35

45

mm.

Greatest transverse diameter proxi-

Greatest transverse diameter, distal

Least transverse diameter shaft

34

PHALANGES, FIRST ROW.

Greatest transverse diameter

21

31

13

25

11

20

S

18

42

75

47

67

39

55

41

152

PHALANGES, SECOND ROW.
Greatest lengtii

61

81

60

Greatest transverse diameter

44

84

46

1

1

i

Pelvis.
Plates 2, .3, and 4.

The pelvis of Stegosaurus is composed of ilium, ischium, and pubis. These allunite to form the acetabulum, which is quite as well closed by bone internally as in
the Ceratopsia.

Apparently these elements never coossify as is sometimes the casein the adult members of the Sauropoda and Theropoda.

—

Ilium (il.). The ilium is the largest of the pelvic bones. Its most prominent
feature is the great anterior extension and the extreme shortness of the postacetabular part, which is scarcely one-third as long as the anterior portion.

The preacetabular process consists of a long, thickened, wide vertical plate ofbone, which terminates anteriorly in a rounded truncate end (fig. 42).
Viewed laterally the superior border of the iUum is curved from end to end,
the anterior process being directed outward and downward in the articulatedBULLETIN 89, UNITED STATES NATIONAL MUSEUM.

78

pelvis which overhangs the posterior ribs.

Viewed from above the superior crest
curves inward and is closely and firmly united with the neural arches of the sacrum.
The ilium does not roof over the cavities between the transverse processes as
described by Marsh ^ but in adult individuals these cavities are completely covered
over, as shown in the sacrum of S. stenops, No. 4934,

by the coalescence of theantero-posterior expansion of the superior surfaces of the transverse processes.
Beginning just anterior to the pubic pedimcle the superior surface widens rapidly
ia a transverse direction posteriorly, particularly on the outer side where the upper

portion is produced outward as a heavy shelf of bone with a thickened roundedouter border overhanging the ischiac peduncle. Posterior to the underlying ischiac
articulation the iUum contracts rapidly in a transverse direction to a short, thickened,

trimcate end placed on the inner side of the bone with roughened surfaces, which
has a greater vertical than transverse diameter. The greatest vertical thicknessof the iUum is through the pubic peduncle and from this point posteriorly thebone is much depressed.

Fig. 42.— Pelvis of

Stegosaueus stenops Maesh. -^hat. size. Side view,is, ischium; p, pubis; p', postpubis.
Aptek Maesh.

a,Acetabuxum; il, ilium;

The acetabular portion of the ilium is large and shallow.

The surface fornevertheless of good size,
consisting of a roughened transversely elongated triangular area with the point ofarticulation with the ischium, while not prominent,isthe triangle directed inward.

The pubic pedimcle while not extending far below the acetabular surface isbroad and heavy as in Triceratops.
On the internal side above the acetabulum the surface is deeply concave vertically with cupped depressions which articulate -ftdth the heavy expanded ends ofthe sacral ribs.

Pubis (p.)—^The pubis in Stegosaurus

is composed of a flattened,late prepubic portion, and a slender, more elongated postpubis.
p'.)somewhat spatu-(See fig. 43, p and

The anterior portion is a thin, vertical blade of bone, terminated usually by avertically rounded anterior end, although a few specimens show it as being cut off

squarely.

While this end is not especially thickened, in fully adulf specimens there
1Amer. Joum. Sei., vol. 21, 1881, p. 168.

.

OSTEOLOGY OF THE AEMOEED DINOSAUEIA.

79

the surface, as shown in figvixe 43. The superior border isbroadly concave antero-posteriorly. Near the proximal end it expands transversely
and on the outer side a rugose ridge is developed extending nearly across the bone
and forming the anterior border of the acetabulum, presenting above a triangularelongated roughened surface wliich meets the pubic peduncle of the ihum. Posterior to this ridge, the pubis is continued backward as a broad process, with a concave roughened external surface that forms the inner wall of the acetabulum, as inTriceratops.
On the ventral posterior border of this process is a small surface wliich
articulates with the antero-inferior process of the iscliium.
Beneath the rugose ridge described above the somewhat slender postpubis isgiven off, extending downward and backward at an angle of something less than
45° to the longer axis of the prepubic portion.
The shaft of tliis portion of the pubis is fairly uniform in vertical width, but
the lower longutidinal half is transversely thickened, with a rounded ventral border,
while the upper half thins out to a sharp edge, wliich is sUghtly roughened.
Marsh ^ shows the postpubis in S. stenops as exceeding the ischium in length(see fig. 42), while in the pelvis of
S. ungulatus it is represented as
is a rugose roughening of

being somewhat shorter.
I am unable to determine fromour material whether this is a con-

Probably

stant difference or not.
it is

The pubic foramen innot.

Stegosaurus

existsalwaysasaborder being
notch, the posterior
^
'

1

mi

^«- «.-left pubis of stegosaukus ungulatus maksu. a nat.
^"'^OUTEK \nEW. p, PK^UBIS; p', POSTPUBIS. Aftek Maksii.

open toward the acetabulum. The
pubes, as with the ischia, appears to have been in contact only on the median Uneat their distal extremities.

In Stegosaurus the boundaries of the acetabulum are even more completely
inclosed by bone than in Triceratops, which Hatcher ^ considered as approaching

most nearly to the mammalia in tliis respect.
Specimen No. 7420, a right pubis and the only complete element in the collection, gives the following measurements: Greatest distance from end of pubis to theend of postpubis, in a straight Une, 850 mm. greatest length of prepubic portion,
460 mm. same measurement of No. 4934, 435 mm. greatest length of postpubis
from anterior edge of notch to distal end, 510 mm.
;

;

;

—

Ischium- (is.)
The ischium is a comparatively short, flat, triangular element,
showing a concave surface only on the Y-shaped proximal end and gradually tapering toward the distal extremity. The larger of the two articular faces on theproximal end meets the ischiac peduncle of the iUum, wliile the smaller andtransversely compressed surface articulates with the pubis a little forward of thecenter of the acetabulum, as shown in figure 42.
Viewed from above, the transversely romided border sweeps downward andbackward from the heavy articular surface, with a gentle curve for over half its
1

Dinosaurs of North America, 1896, pi. 48, flgs. 2 and 3.

-

Mon. 49, U. S. Geol. Surv., 1907, p. 57.

—UNITED STATES NATIONAL MUSEUM.

80

length, where a roughened elevation is met.

tapers rapidly to the blunt truncatedend

From this point posteriorly the ischia
(fig.

44),

which is triangular in cross-

The height and rugoseness of this elevation on the superior border of theischium is more pronounced in fully adult specimens. The inferior border presents
section.

a thin, sharp edge, except at the transversely expanded
distal extremity,

which is flattened and has a roughened

surface that appears to have been closely appHed to thepostpubis. In the restoration of the pelvis of Stegosaurus(fig.

42), Marsh* has indicated theischium and postpubis

as being in contact along their whole length, but it would

appear from the study of specimens in the National Museum
collections that there was a longitudinal cleft between them,as in Omosaurus.

In plate 80, figure 5, Dinosaurs of North America, Marshshows the distal third of the ischia as meeting on the medianline.
The shortness of these bones, in conjunction with theFig. 44. Eight ischiumofgreat width of the sacrum, appears to make such a imion
STEGOSAtrKUS UKGTJLATUS
impossible, and in an impublished plate of the articulated
MAESH. -^ NAT. SIZE. INTERNAL VIEW. a, ANTEKIOR
sacrum they are shown only in contact at their ends. Furend;
AETICULAK END FOE
thermore, none of the seven iscliia in these collections shows
iltom;
p, pubic akticulation; s, stmphysial border.
inner surfaces adapted to or even suggestive of such a cartiAfter Marsh.
laginous symphysis. It is also noted that in the mounted
skeleton of S. ungulatus in the Peabody Museum of Yale University the ends of theischia are not in juxtaposition (pi. 36).
Nopcsa ^ lays particular stress on the cleft between the pubis and iscliium. He
i,

says:

The longitudinal cleft between the pubis and the ischium, which is present in both species ofOmosaurus and our Stegosaurus [S. prisms] is a character found in all primitive Ornithopoda; the closing of this cleft observable in S. ungulatus must, therefore, be regarded as a mark of specialization.

In view of what is now known of the manner of articulation of these bones,
httle weight is to be given Nopcsa's observations.
Measurements of ischia.
No. 4934.

No. 2111.

mm.

mm.

555

490

280

262
55

195

Hind Limb and Foot.

Femur

The femur of Stegosaurus is by far the largest bone in the skeleton.
remarkably long and slender, with a very straight shaft of nearly uniform
width, being somewhat compressed from front to back. The head is. not distinct,
It is

'

Amer. Joum. Sci., vol. 21, 1881, pj. 8, fig. 2.

!

Geol. Mag., vol. 8, No. 4, p. 151.

OSTEOLOGY OP THE AEMOEED DINOSAURIA.

81

although there is a f amt constriction connecting it with the shaft of the bone tis in
The great trochanter is not separated from the head, but as in the
Diplodocus.
Sauropodous dinosaurs the rugose proximcl surface of the latter continues uninterruptedly and covers the superior surface of the great trochanter. The head of
the femur of Stegosaurus prisons Nopcsa is strildngly different from any of the American
having a distinct head and an elevated trochanter major.' In these
forms,
respects it resembles Triceratops more nearly than Stegosaurus.

m

-A

A

of Stegosaurus femora. Viewed from the front. All
nat. size. (1) Femur
OF S. UNQULATUS MARSH. COTYPE. YALE MuSEUM. (2) FeMUR OF S. ALTISPINU3 GlLMOEE. TYPE. UNIVERSITY OF
Wyoming Collection. (3) Femur of S. stenops Mar.sh. T^te. No. iM4 U.S.N.M. a, lessee trochanter; b, greater
trochanter; h, HEAD.

Fig. 45.— Comparative views

In the collections of the National Museum there ai-e 10 Stegosaurian femora,
but on none do I find a rugose area extending down any appreciable distance on the
superior external surface, such as noted by Osborn ' in Diplodocus, although on somespecimens there is a rugose area running down on the outer anterior surface as in
Mastodon and Elephas.
A small finger-hke proximal or lesser trochanter, called great trochanter by
Owen in Iquanodon, is present in S. stenops (3, fig. 45. a.) and on all the other femora'

F. Baron Nopcsa, Ceol. Magazine, vol. S, No. 4, 1911, p. 147, fl?. 6 (c).

"Mem. Amer. Mus. Nat. Hist., vol. 1, pt. 5, 1«99, p. 211, fig. 14 (a), tr. I.

—.

UNITED STATES NATIONAL MUSEUM.

82

before me, although, it appears to be absent in S. ungulatus (fig. 46) and the aUied
The presence of this atroj^hied trochanter, which is such aEuropean forms.

prominent feature ofallbipedal dinosaurian femora, apparently represents therenmant of a much larger process, which has been handed
down from a bipedal ancestry.

With the exception of haAong the trochanter just described,
the whole proximal end of the femur of Stegosaurus is remarkably hke those of the Sauropodous dinosaurs, especially that of
Diplodocus.

Marsh has pointed out the absence of the third trochanter (now recognized as the fourth) in S. ungulatus and I
find it absent in S. stenops. The origin of the caudo-femoral
muscle is nevertheless usually indicated by an obtuse longitudinal sweUing, which fades out rapidly both above and be'low.

As shown by Nopcsa in S. priscus "it must be considered

In specimen No. 7380, of
which we have both femora preserved, the vestigal fourth
trochanter is roughly rugose. In the American Stegosaurus the
fourth trochanter appears always to be more vestigal than inas the last trace of this trochanter."VI

TriceratojJS.

The distal end of the femora is more expanded transThe external condyle, as usual,
The intercondylar notch is wideis larger than the internal.
and moderately shallow. The external condyle has on its
versely than antero-posteriorly.

outer side a shallow groove which probably transmitted oneof the strong tendons.
Nopcsa ^ has contributed some interestmg observations

on the Stegosaurus hind Hmb, which are given herewith:Iofmah to emphasize the fact that in this genus [Stegosaurus} the amountcartilage on both ends of the femur was decidedly much greater than in

the Ornithopodidce, and that the shape of the proximal and distal end of thebone must have been originally somewhat different from the present shape.
The lack of a trochlea on the distal end of the femur of Stegoshuncs cangive us a clue to the amount of cartilage missing, for Stegosauruk, being aterrestrial animal, can not have walked, and especially sat down without
bending its knees sometimes for more than 90°, while as shaped in thefossil the tibia would become dislocated if forced to make an angle of morethan 45° with the femur. This tends to show that the cartilage on the
distal end of the femur must have been at least 4 cm. thick, and this iscertainly not too much when we consider that the distal femoral cartilage of the macerated Gallus figured
above had a thickness of 4,5 mm., while the femur itself measured 94 mm. in length. It becomes evident that just as we could never try to bring the macerated femur of Galhts into correct juxtaposition
to the acetabulum without allowing for a great amount of cartilage, so we can not base any conclusion
Left femue or
SlEGOSAUEDS UNGULATUS
Marsh,
i nat. size.
Fkont tie-w. c, innercondyle; s, shaft showing ABSENCE OF FOURTH
trochanter;t,great
trochanter.
After
Marsh.

Fig.

46.

as to the position or direction of the femur in Stegosaurus exclusively on the shape of its articular surface.

*

*

*

Even by those who hold the contrary view of the amount of cartilage in Diplodocus it is thought
to be correlated with the aquatic habits of this monster, but this theory can not apply to the heavily'

Dinosaurs of North America, 1S96, p. 191.

•

Geol. Ma.?., vol. 8, No. i, 1911, pp. 147-148.

:.

OSTEOLOGY OF THE ARMORED DINOSAUEIA.
armored Stegosaurus.

I quite83

believe that the feeble ossification of the sternal apparatus and the low

degree of ossification of the distal carpals and tarsals in most Dinosaurs are much more likely to explain
the great cartilage caps on the femora of the Stegosauridte and similar animals than the hypotheticalaquatic habits. These features and the coarse structures of the bones indicate a low degree of ossificationin the whole body, and the great masses of cartilage were probably needed to ensure the continuous
increase of size throughout life.

Lull ' says

The loss of this trochanter [the fourth] together with the slight development of the pubic peduncleof the ilium precludes the possibility of a bipedal gait, though doubtless Stegosaurus is derived from abipedal ancestry, quadrupedalism being secondarily acquired as in the Ceratopsla, owing to the immense
weight of the creature's armament.

A comparative studj* of the series of femora in the National iluseum collections
shows the existence of two types of animal one a distinctively slender, longlimbed form, the other a short-limbed type. The former reaches its maximum
development inS. ungulatus as shown in the mounted skeleton (fig. 46 and pi. 36).
The latter is represented by a hind limb, No. 7380. The femur of this specimen

—

is

'

of a fully adult animal, as evidenced by the rugose nature of the articulations

and areas of attachment for the more important muscles. The articular ends
and condyles are especially well defuied and in every way have a more finishedappearance than any of the longer femora in the collection. A small humerus,
No. 7409, but not associated -with the hind limb mentioned above, also exhibits
characteristics similar to those of the femur described above.
Whether these bones represent an undescribed species, I am not prepared todecide at this time, but that there are long and short limbed forms of the genus
Stegosaurus, the evidence before me appears most conclusive.
The femora of S. stenops and S. longispinus show these species to be classed
It is quite possible that when the femora of the otheras long-limbed animals.
described species are Icnown it will be found that these short-limb bones pertain
There is also the possibility that the matter of sex may accountto one of them.
for the difference in the size of the limbs.
Measurements offemora.

S. stenops,

S. un-

type No. 4934.

gulatus.

Eight.

6646,
right.

No.
Lett.

S. longi-

Stegosaurus sp.

spinuSj
type.

No.

No.

No.

7380,
right.

73S0,

left.

left.

7385,
right.

No'.
7370,

Eight.

771771.

77im.

mm.

mm.

771711.

mm.

1,080

1,010

1.200

977

908

895

860

1,082

Greatest breadth at proximal end . .

283

307

329

245

268

225

275

Greatest breadth at distal end

276

269

263

227

246

242

192

242

14.5

140

147

130

128

128

117

132

mm.

1

Amer. Joum. Sol., vol. 30, 1910, p. 367.

—.

UNITED STATES NATIONAL MUSEUM.

84—

Tiiia {t.).
lu Stegosaurus stenops, the tibia is very much shorter than the femur,
the ratio being as 1 1.68.
:

The tibia of Stegosaurus may at once be distinguished by the unusual angulaexpanded ends; that is, the greatest diameter of these extremities
same plane, while in the Ceratopsia and CamptosauridEe thesediameters occupy planes nearly at right angles to one another. Articulating
the proximal end of the tibia with the femur as in Camptosaurus, Triceratops, orTrachodon tends to throw the articulated foot out at right angles to the longer
tion of thelies

in about theaxis of the body.

This at once raises the question as to the correctness of theinterpretation of the articulation of the limb as shown by
various figures and illustrations.
The proximal end shows on the posterior side two comparatively small condyles which overhang the posterior sur-

The external border of this end is shallowly'
concave antero-posteriorly for the reception of the proximal
end of the fibula. On the anterior side is a broadly rounded,blunt enemial crest. The least diameter of the constrictedshaft is below the middle. The distal end is widely expanded
antero-posteriorly, but without marked expansion transversely.
On the anterior face of this end the surface is un-face of the tibia.

equally divided

by a broad,shallow, longitudinal groove,

which probably transmitted the tendons of the flexor musclesof the foot.

The smaller or external part represents, in func-tion at least, the external maUeous of the

mammahan tibia.

below the internal surface with which the astragalus unites, and articulates on its inner side with thatbone. The anterior surface of this part is flattened andarticulates closely with the fibula (fig. 47)
It extends

Left tibia and fibula OF Stegosaueus unGULATUS MAESH. ii NAT.
SIZE. Feont view, o, as-Fig. 47.

tragalus;/, fibula;

Marsh.

C,t,

CALCANEUil;

TIEIA.

After'

The articular surface for the astragalus is cupped.

This

surface is irregularly gouged out (fig. 48), into which fit corresponding projections on the proximal end of the astragalus.

This union renders the bones immovable upon one another and brings about a condition favorable to their early coossification, as evidenced by the ankylosis of thesebones in four of the six tibia preserved in the National Museum collections.
A front view of the tibia is shown in figme 47.
Measurements of tibia.
Stegosaurus sp.
S. stenops,

S. uvgw-

type ISO.

latus, No.

4934, right.

6d46, right.

No.

No.

No.

7379, left.

7380, right.

7387, right.

mm.

mm.

643

696

602

565

570

265

275

230

210

210

245

217

185

232

98

87

77

79

85

OSTEOLOGY OF THE ABMOEED DINOSAUKIA.
Fibula (J.).

—The fibula85

is slender, with the proximal end heavier than the distal.

The tibial side of the upper end is hollowed out in order to better conform to the

An obtuse thickened ridge passes
diagonally across the inner surface, about 70 mm. below the proximal end, andserves to distinguish the fibulae of Stegosaurus fi'om those of other known dinosaiu's.
surface of the tibia, with which it articulates.

The proximal articular surface is rounded and rugose and quite on a level withthat of the tibia.
Tlie surface next to the tibia is plain, while the opposite side is iiTegularly con-

The distal end, much flattened and expanded antero-posteriorly, was closely

vex.

applied to the flattened surface of the tibia.

A somewhat roughened area for muscular attachment passes diagonally acrossThe distal end when articu-

the outer surface just above the center of the bone.

FiG. 48.— Distal end of bight tibiah.

op Stegosackus sp. Cat. no. 7387 U.S.N.M. } nat. size, a, external bokder,
anterior border;./, surface for fibula. Dotted line shows position of astragalus when articulated.

lated rests upon the very small calcaneum.

In some individuals it has been foundto coalesce with the calcaneum, these in turn with the astragalus and tibia, forming

a smooth convex articulation for the ankle joint.

The principal features of thefibula are shown in figures 47 and plate 25, fig. 5.
Measurements of fibulae.

'

S. stenops.

Stegosaurus sp.

Type.

No." 4934.

No. 7389. No. 7380. No. 7390. No. 6644. No. 7384.

mm.

51873°— Bull.

mm.

mm.

mm.

610

S15

518

548

579

550

109

78

81

71

82

72

74

90

79

68

99

95

38

38

47

38

41

.

UNITED STATES NATIONAL MUSEUM.

—

Hind foot. The proximal row of the tarsus is composed of the astragalus andcalcaneum, the distal row apparently remaining unossified. In adult individuals
the astragalus usually coossifies with the tibia; calcaneum generally remaining as
a distinct element, although in two instances it was found ankylosed with thefibula.

A complete articulated hind foot of Stegosaurus is as yet unknown, althoughassociated foot bones enable me to determine the chief features of the structure of
the pes.

In the hind foot there are three functional digits, with the rudiment of a
The latter, as first determined by O. C. Marsh, was thought to represent a
remnant of digit one, but, as I shall attempt
to show, probably represents the fourth.
The fifth appears to be entii-ely wanting.
In the fu-st restoration of the hind foot'fourth.

Marsh showed five digits, evidently drawn
from a fore foot, but this error was correctedby him in a later restoration.^
Astragalus (a.)
The astragalus in Steg-—

reduced to a flattened, disk-likebone, having a regular concave plantar surface and an irregular convex proximal surViewed fi'om above it is suboval inface.
outline, the longer diameter being transverse.
Fig. 49.— Astragalus op Stegosaurus sp. Cat. no.
When articulated, the end of the tibia more
Proximal view.
7387, U.S.N.M.
J NAT. SIZE.
than covers it (see fig. 48). Externally itmeets the inner border of the calcaneum, with which it is often ankylosed.
The median superior surface is covered with rounded protuberances (fig. 49),
which fit into corresponding depressions in the cupped surface of the distal end of
the tibia, thus rendering the two bones immovable upon one another. This joint,
osaurusis

as mentioned previously, is most favorable for then- early coossification, a condition

observed in nearly all fuUy adult individuals.
Although Marsh included this character in aU of his definitions of the family
Stegosauridse, he was apparently well aware of its being an age characteristic, as
evidenced by the following " In the Stegosauridse alone, among known dinosaurs,
This, however, is not a character ofis the astragalus coossified with the tibia.
:

much importance." ^Measurements of astragali.
Stegosaunn, sp.

No. 7378.

No. 7387, No. 6646, No. 7380.
right.

right.

104

95

122

76

110

112

115

87

mm.

mm.
Greatest diameter anteroposterior! y1

Amer. Joum. Sci., vol. 21, 1881, p. 169, pi. 8, fig. 2.

«

Idem., vol. 42, 1891, p. 180, pi. 9.

'

Idem, vol. 23, 1884, p. 336.

'

OSTEOLOGY OF THE AKMOKED DINOSAUKIA.

87—

Oalcaneum (c.)
The calcaneum is represented in the Museum collections by fivespecimens, of which three are articulated with the tibiae. Viewed externally it is a.

small angularly rounded element, with the greatest diameter supero-inferiorly.
The external surface is comparatively smooth, being sHghtly con-cave vertically. The tibial side is
deeply concave from above downward, this surface in the articulated
limb closely unitiag with the distal
portion of the external malleolus.

The bone thins out ]iosteriorly, but
The internal
thickens anteriorly.
border for articulation %vith the astragalus is much roughened.
The
anterior border is regularly roundedfrom above downward and conforms
closely with the convex surface of
the astragalus. The proximal end
presents a roughenecl beveled articular surface for the fibula, thebevel being toward the tibial side.

50.— Right calcaneum ok Stegosaueus sp. Cat. no.
U.S.N.M. } NAT. size. (I) Lateral view; (2) front
view; c, border akticdlating with the astragalus; d, doesal BORDER WHICH MEETS THE FIBULA; V, VENTRAL BOEDER.

Fig.

7367,

The chief features of this bone are well shownin figure 60.
Measurements ofcalcanea

No. 7397,

No. 7398,

No. 6646,

No. 7368,

right.

left.

right.

left.

mm.

mm.

mm.

mvi.

Greatest antero-posterior border

07

65

75

71

Greatest transverse diametor

34

30

38

•11

Greatest height

7(i

80

103

87

Metatarsus.

—The metatarsus of Stegosaurus consists of four bones, of which

three are large and support functional toes, and one is rudimentary (figs. 52 and 53).

The functional metatarsi are exceedingly stout, robust elements, the median one
being the longest of the three. Their proximal ends were evidently bound together
by strong ligaments, there being no interlocking articular facets as found on themetatarsals of many of the bipedal Ornithopoda.
Thefoot of specimen No. 42S0, shown asfound insitu, in plate21, figure 1, appears
This digit has two phalanges, and on theto have one digit preserved in its entirety.
analogy of other dinosaurian hind feet, as shown in the table below, would indicatethat it represents the innermost or firet digit.
On the evidence of this one foot it
was so regarded when the drawing for figure 52 was made.

—

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.
Phalangial formula of known dinosaurian hind feet:

n

1

m

IV

ScelidosauTus harriaonii Owen

CamptosauTus dispar Marsh
TkescelosauTus neglectus Gilmore

BTOchyceratops montanensis Gilmore

Iguunodon bernisswrlensis Boulenger.
TTachodon anneetens (Marsh)
Diplodocus carnegii Hatcher

BrontosauTus excelsus Marsh

The more recent discovery of an articulated limb (No. 4936) throws considerable doubt on the above interpretation, and I am now inclined to the opinion that theungual does not belong to the digit as shown in figure 52, III, but was shifted into its
present position from one of the other toes, as shown in plate 21, figure 1. The
evidence for this is, first, the great resemblance of the short metatarsal to metatarsal I
of Sauropodous dinosaurs, and, second, the finding of a disarticulated foot in the rocknear and around the distal ends of a tibia andfibula which were articulated with the femur.
If this association is correct, it shows the shortmetatarsal to be on the inside of the foot, andwould therefore be metatarsal I as indicatedUpon other evidence Marsh has
given this bone a similar position in the hindfoot, as shown in his restoration (pi. 32, upperin figure 52.

Metatarsal II of eight hind foot of
Stegosahrus tjngulatus Marsh. J nat. size.
Sn)E VIEW; 6, front view. After Marsh.

Fig. 51.

a.

figure).

From the great resemblance of thisshort metatarsal to the homologous element in
the hind foot of Brontosaurus and Diplodocus,

I regard it as representing metatarsal

I,

and the rudimentary metatarsal I would

consider as the remnant of Digit IV.

The loss of the fifth digit and the reduction of the fourth to a vestigal metatarsal shows that the reduction in the pes of Stegosaurus

has taken place from theoutside of the foot as in the Sauropodous dinosaure rather than from both outerand inner sides, as in some of the Ornithopoda.
It may be that there is a progressive increase in the number of phalanges in
Digits I to III so characteristic of nearly all dinosaurian reptiles, but I am inclined
to beheve that when the complete formula is known it will be found that Digit III

lacks the ungual and perhaps one or more of the phalanges.

Metatarsal I is an exceedingly short, stout element, the width about equaling

The proximal end is wider than deep, thus reversing the measurements
Viewed from the front the whole bone is beveled off
toward the outside. The chief characteristics of this element are shown in plate 21,
the length.

of the median metatarsal.
figure 1, I.

Metatareal II may at once be recognized by the transvereely compressed proximal end and the greatly lengthened antero-posterior diameter of this end (fig. 51).

OSTEOLOGY OF THE ARMORED DINOSAURIA.

m

The slightly concave proximal articular surface does not reach the back but thebone develops a strong, roughened, overhanging tuberosity for ligamentary attachment.

The shaft is constricted, thedistalend about evenly expanded,with broad, shallow median groove.
distal articular surface extends
well up on the anterior face of the
shaft, as it does in all three metatar-

The

On

sals.

the

external side oftheanterior surface, below the center, avertically elongated, tuberosity withroughened surface

isdeveloped, as

shown in figure 52, t.
Metatarsal III has an irregularlyrounded ])roximal end, with slightly
concave, roughened articular surface.
The shaft is constricted in all diameters, but more especially the trans52.— Right hind foot of Stegosaukus sp. Cat. no.
U.S.N.M. About i NAT. size.
Deawn articulated.
Sesamoid; t, tuberosity; I, II, III, digits one, two,and three. Ungual on digit III probably pertains todigit one.

Fig.

verse.

The distal end has two surfaces
which meet at an obtuse angle on
the internal third of this end.

The

4280,
s,

rounded internal surface articulates with the first phalangial, while the externalsurface turns somewhat backward, remaining free.
Metatarsal IV consists of a small, slightly flattened element,with rounded distal and a pinched-off proximal end, the latterwithout articular surface. If my interpretation of the respective
ends is correct, then this digit would have one or more phalanges;
but on the other hand, if they have been reversed it would represent all that remains of this digit. The upper end is somewhat
roughened, as shown in figure 53.
Phalanges. The complete phalangial formula of the hind foot—is unlmown.
The partially articulated foot (No.
42S0) shown in plate 21, figure 1, has the proximal row of phalanges of digits I, II, and III preserved in their proper relations toof Stegosaurus

the metatai-sals, and is the only specimen in the collection in the
United States National Museum furnishing positive evidence as
to their proper arrangement.
No.
7419,
Cat.
U.S.N.M.
NaturalThe proximal phalanges in all of the digits are short and
SKE. a, Articular
end; 6, PINCHED off
broad, relatively much heavier than those of the manus. TheirPROXIMAL END.
proximal ends are shallowly concave from above downward andTheir distal ends are convex from above downward, with aslightly roughened.
broad, concave transverse median depression.
The proximal phalanx of digit I is a short, broad bone which articulated witha broad, depressed hoof-like ungual (fig. 54) with roughened surface, which in life wasFig.

53.— Vestigal

metatarsal of
Stegosaurus sp.

,

'UNITED STATES NATIONAL MUSEUM.

90

doubtless incased in a horny hoof. Marsh, in the restoration of Stegosaurus
ungulatus (pi. 32, upper figure), regarded this digit as the second, and on that
account it has been given three phalanges.
The proximal phalanx of digit II (fig. 52) may be recognized at once whenviewed from above on account of its bilateral symmetry. In this aspect the proximal phalanges of digits I and III are wedge-shaped, with the least antero-posterior
diameter away from the center of the foot.
The first phalanx of digit II (fig. 52) had a small fiattened discoidal element
attached by matrix to its distal end. This element either represents a rudimentary
second phalanx of this toe or a sesamoid bone. I am inclined to believe it to be
the latter. A similar element was found with the disarticulated foot bearing thenumber 7415. These probably represent
phalangial sesamoids such as Hatcher
found in the manus of Brontosaurus.

Nothing is known of the positive
arrangement of the other phalangials or
unguals, and we must await the discovery of more complete material for thedetermination of the digital formula.
The pes, as in the manus, is digitiAfter Marsh.
grade. The roughened articular ends ofthe metatarsals and phalanges indicate the presence of thick pads of cartilage
between the joints.
That the foot was well arched is shown by the wedge-like proximal end of
metatarsal II and the oblique proximal phalanges of digits I and III.
The ungual of digit I if articulated would turn obliquely inward toward the
median line of the body. Other unassociated unguals show the ends to be obliquely
truncated toward the mesial line, as the one shown in digit III (fig. 52) of No.
4280. There are one or two others which are more symmetrical, and probably
represent the terminal phalanx of the median toe (Mt. II). With the associatedhind-foot bones of No. 4936 there were two disarticulated unguals present, butwhether digit III bears a flattened claw remains to be determined.
The general character of the bones of the hind foot suggests that the feet of
Stegosaurus were much like those of a large tortoise, club-like, with the toes turned
well downward.
Fig. 54.— Tekminal phalanx of Stegosaueus sp.
SIZE,

a,

J-

nat.

Front view; b, side view; c, posterior view.

Measurements oflhe elements of the pes.
"

METATARSALS.
No. 4280.
I

u

III

mm.

mm.

mm.

76

m

100

76

55

68

76

60

34

43

33

35

31

60

61

65

PHALANGES, FIRST ROW.

1

Ann. Carnegie Museum, vol. 1, 1902, p. 373, flg. 13, pi. 19.

.

OSTEOLOGY OF THE ARMOEED DINOSAUKIA.

91

Dermal Aemok.
Plates 2, 3, 4, 11, 12, 13, 14, 15, 16, 17, 18, 22, 23, 24, and 25.

The exoskeleton of Stegosaurus consists primarily of four types of structure;
the so-called gular or throat scutes covering the neck and possibly the head (pi. 22,
have not been placed but probably

figs. 2 and 3) ; the isolated rugose ossicles whichwere scattered over the skin (fig. 56); the series of erect plates forming two rows
along the neck, back, and tail (pi. 14) and the elongated, spike-like spines placednear the end of the caudal series (pis. 15 and 16)
Dermal ossicles (o.). The first type, consisting of small, depressed, angularlyrounded ossicles, was found in the rock near the skull and neck of No. 4934 (pi. 2,
ako pis. 3 and 4, o). These ossicles are of irregular sizes, but none exceeds 35 mm. indiameter (see fig. 55). It might be mentioned that similar ossicles were found withthe skeletons of three other individuals, Nos. 4936, 7615, and 7947, in the collec(See two of these in pi. 22, figs. 2 and 3.)tion of the National Museum.
Nearly all of these structures have one flattened side with a sculptured surface,
but without distinct pattern. The pits and grooves forming the sculpture are mostpronounced in the center of each
^
;

—

From

ossicle.

thepositionof^^^some few of these that still re- ^^mmain attached to the cervical ver- ^S^^
tebrae by matrix, i am led to be- ^^^ 53._deemal ossicle of stegosaueus trNGuuATus maesh. ^ nat.
lieve that the flat, sculptured face
1

1

•

J

1,

represents the external side shown,,,in plate 22, figure 2.

If thisSupeeioe view; b, side view; c, infeeioe view. If thegiven this is an exceptionally laege ossicle.

size,

a,

scale

is coeeectlyj^^^ maesh.

becorrect the patches of ossicles present on either side of the neck, as shown in plates

2 and 3, o, have their internal surfaces uppermost (pi. 22, fig. 3). There is no positive evidence to show that they were confined to the under side of the jaws andthroat as indicated by Marsh in his restoration of Stegosaurus (pi. 32, upper figure).

From the position of those found with No. 4934, it would appear more probable thatthey covered the sides of the neck from the base of the erect plates downward,
scattering, if at all, on the ventral areas, this region being protected by softer skinwithout bony scutes as in most modern reptiles.
After a careful comparison of the Heloderma skull and its investing skin tubercles(compare figs. 1, 2, and 3, pi. 22) with those of Stegosaurus, it appears probable thatthese ossicles formed a similar investiture of the superior portion of the Stegosaurian cranium. Tjiere may have been evidence bearing on the above suggestion, butwhen the skull came into my hands it had been entirely divested of its matrix, thus
destroying all traces of closely associated ossicles.
That these extended to other parts of the body is shown by ossicles found near
the tenth and eleventh vertebrae and stiU others attached to the sixteenth vertebra, and more posteriorly two were found at the base of the tenth plate near its
posterior border.

That they did not form a continuous investiture of the sides of

the animal is shown by their absence from the matrix between the ribs of the left
side and the underlying dorsal armor, for surely the skin must have been present

here when the carcass was entombed.

UNITED STATES NATIONAL MUSEUM.

92

None of the isolated dermal structures figured by Marsh have been recognizedwith any National Museum specimen (fig. 56).
The plates borne upon the neck immediately posterior to the
Nuclial plates.
skull are small, thin, vertically elongated, with roughened basal ends, withoutmaterial transverse expansion, except in very old individuals. In specimen No.
4934 there are five of these small elongated plates as shown in plate 14. These
gradually increase in height from front to back. As
shown by No. 7615 (pi. 23, figs. 2 and 3), they are flattened on one side, probably the external, and slightly—

Fig. 56.— Tubeeculak

spineof Stego-

SAUEUS UNGULATUS MAESH. y>j NAT.
SIZE, a, SUPEEIOR VIEW; 6, INFEEIOR
After Marsh.

view; c, ENii VIEW.

convex antero-posteriorly on the opposite side. The
depth of the insertion of these plates in the skinappears to be indicated by an abrupt transverae
constriction some 40 mm. above the basal end, wellshown in figure 57, g.

The character of the surfaceof this portion is also changed, inasmuch as the vasculargrooves of the upper surIn other specimens this surface isroughened with fine interrupted ridges of bone, their general trend being anteroposteriorly.
In some of the above plates there is a slight transverse bevehng of
the lower end, and all agree in having^^
one large foramen leading up into thefaces end abruptly at the point of contraction.

interior of the bone.

—

Dorsal plates. The small elongated plates are succeeded by larger
more or less oval plates, with transversely expanded bases, of very shortfore and aft extent as compared mth
the longitudinal diameter of the upper
portion, apparently a provision for
greater freedom of movement such as
would be I'equired in the region of theshoulders (pi. 23, figs. 4, 5, and 6). In
specimen No. 4934 there are four ofthese oval plates with bases cleftlongitudinally. These increase rapidly
in size, as is shown in plate 14, Nos. 6
to 8.
The bases of these plates are
somewhat asymmetrical, with exterior

andinterior surfaces

about equally

57.— (1) Side and (2) posterior views of nuch-vl plate
OF Stegosaueus sulcatds Marsh. Type. Cat. no. 4937,
U.S.N. M. i NAT. SI2E. a, Anteeioe bordee; g, geoove showing depth of insertion in the integument; p, POSTEEIOE
border.

Fig.

The asymmetry of the bases
would indicate that the plates wereinclined sUghtly outward from the perpendicular when held in the sldn.
As inthose plates on the anterior portion of the neck the external side is flattened, while
the internal is slightly convex antero-posteriorly. Other specimens, as No. 7584
(pi. 23, fig. 5), show similar plates to have transversely enlarged bases, but without median cleft.
rugose.

OSTEOLOGY OF THE AEMOKED DINOSAUBIA.

93

The oval plates are succeeded by two or more of a subrectangular outline withrugose bases having but little transverse thickening, but not cleft longitudinally
except in young individuals. Their approximate shape is shown well in plate 14,
although some of the upper portion is missing from plates 10 and 11 (pi. 14); these
are in turn followed by the thin sub triangular plates of the sacral and anteriorcaudal region. Good examples of this latter style are shown in plate 24, figures 3
and 4. In these plates I am unable to find differences that would enable one todetermine the exterior from the interior surfaces. The bases are symmetrical, both

surfaces equally rugose and evenly covered with vascular grooves.

—

Caudal plates. In the consideration of the remaining dermal structures of thea second specimen, No. 4714, in the National Museimi supplements the one
just described to such an extent that it is possible to give an acciu-ate accoimt oftailthe entire dermal series.

This specimen consists of an articulated series of 44 caudal vertebrae with therow and thedermal spines in sequential
plates of one

58).

The rela-tive positions ofthese ele-

position(fig.

ments as found was determined from an accuratelydra^vn map (fig. 58, also Dia-gram 5, map of quaiTy 13,
pi. 37) made at the time thefossil was collected.

A comparison of thesevertebrae with those of thearticulated
skeleton(No.
4934) indicates that between
5 and 7 vertebrae are lacking

Fig. 58.— Sketchfrom the proximal end tofeom diagrams 5 and 7 of map of quarry 13 shotting
relative positions of dermal plates and caudal vertebrae in tailof stegosaurus stenops. cat. no. 4714, u.s.n.m. o, anterior caudal
vertebrae; 6, dermal spines with tip of tail (see plate 14). 10, 75,
76, AND 177 original QUARRY NUMBERS OF DERMAL PLATES.

complete the caudal series.
It was also observed that thelargest plate occupied the same relation to the tail as the corresponding plate in(Compare 2514, pi. 3, with pi. 13.) This apparthe Stegosaurus stenops skeleton.
ently establishes the position of the largest plate to be above the base of the tail,as correctly placed by Marsh in his first restoration (pi. 32, upper figure), and not,as in later conceptions, above the sacral region.
Posterior to this plate and in regular order are thi-ee other plates of diminishing(PL 24, figs. 4, 3, 2, and 1; compare with caudal
dimensions, as in No. 4934.
plates No. 4934, pi. 2.)

Measurements demonstrated the fact that the length of the remaining articulated caudals, i. e., to a point where the dermal spines attach, exceeded by 8 inches(206 mm.) only, the total longitudinal diameter of the three plates, barely enoughbetween the plates. This would appear to show

to account for the interspacesthat there were only three plates posterior to the largest of the series, or six for thetwo rows. Adding this number to the 14 actually shown in position more anterior

:

UNITED STATES NATIONAL MUSEUM.

94

to them would give us 20 as the total number of these flat plates, whereas Marsh,
in his first restoration, has 12 in a single row (pi. 32, upper figure), Lucas 30, 24 and22, respectively, in his restorations (pis. 33 and 34), and Lull 28 in the latest con-ception (pi. 36).
It is of interest to note that the plates of specimens Nos. 4714 and 4934 whencorrelated on the basis of their relative positions as found in the field (compare pi. 2
and fig. 58) agree very closely in measm-ements and in general contours. This
correlation is shown below
Correlation of plates of the tail in two specimens.

No. 4934.

No. 4714.

Greatest
longitu-

Greatest

Greatest

longitu-verticalGreatest
verticaldinal
diameter.
diameter.

dinaldiameter.
diameter.

mm.

mm.

mm.

mm.

650

580

P. 13....

695
785

760

No. 95
No. 10No. 75770

70O

P. 14....

660

620

P. 15....

630

627

No. 76
No. 177

420

320

P. 16....

410

335

P. 17....

290

225

295

210

On the evidence of these two individuals it would appear that there were only twoof the sharp-edged overhanging distal plates (pi. 24, figs. 1 and 2) on the taU, whereas

the Yale mount shows six.

^

,

In

the first restoration by Marshnone ofthis type

cated

32,

were indiupper figm-e).
Had such a plate been inserted
by him it would have necessitated the removal of the two(pi.

anterior pau-s of spines in or-

der to make room for it, butsuch a change would havebeen in accord with the sequential order of these bones,
as shown by the evidence pre-Fig. 59.— (1)Lakge dermal spine of Stegosaubus Ungulatus Marsh.
view

tV NAT. SIZE, a, Side view; 6, front view; c, section; d, inferior
POSTERIOR view;op BASE. (2) SMALLER CAUDAL SPINE OF SAME,OTHER LETTERS SAME AS IN NO. 1. AFTER MAKSH.

sented here. That the diminution in the size of the plates
from the largest to the smallest was a regularly graduatedchange and not

an abrupt

transition, as seen in the Yale mount (pi. 36), is abundantly shown.
I can not accept Lull's ^ statement, when, in discussing the distal plates of thetail, he says "the base being
1embedded in the muscles between the neural spines andVerhandlungen des VUI.

Internationalen Zoologen-Kongress zu Graz, 1912, p. 676.

—

OSTEOLOGY OF THE ABMORED DINOSAUKIA.

95

the vertebral centra," for surely were they so attached the function of these muscles
would be destroyed. Like aU the other dermal structures of this animal, I behevethese bases were embedded entirely within the thick skin.

Dermal s fines.

—Of the remaining dermal structmres only the spike-Hke spines,

situated near the end of the tail, are yet to be considered.

The number of thesespines, with the possible exception of 8. ungulatus, appears not to have exceeded

four, arranged in

two pairs.

Lucas was the first to reach this conclusion fromthe evidence of two specimens which showed them in place (pis. 15 and 16).
That four is the correct number is now substantiated by the evidence shownby sixindividuals, five of which arein the National

Museum.

^The fore-most pair is always the larger of thetwo. I have before me 30 of these

,
;
j

j
j

spines, representing at least 10 individ-

These specimens exhibit a considerable variety of shapes and sizes,
ranging from 7 inches (175 mm.) long
uals.

in a

young individual (pi. 25, fig. 2)

to more than 3 feet (985 mm.) in thetype of S. longispinus, an adult speciAll agree in having
oblique bases, but in the expansion ofthis end they vary from the nonexpanded ends of S. longispinus and S.
stenops to the exceedingly large basesmen (fig. 60, A).

of S. sulcatus

(fig.

60).

The spines ofthe young individuals (pi. 25, figs. 1
and 2) are without rugose rougheningof the bases, but the adults are very

rough, reaching theirmaximum de-velopment in S. sulcatus (pi. 18).
All of the spines have the surfaceof the oblique end shallowly concave
dorso-ventraUy. On this end there isalways one large pit, which leads up
into the interior

of

the

shaft.

Dekmal tail spines. A, Stegosaubtjs longispinus.
D 54, Ukivebsitt op Wyoming collection. B,
STEGOSAURUS StTLCATUS. TYPE. CAT. NO. 4937, U.S.N.M.
C, STEGOSACHUS UNGULATUS. CAT. NO. 6099, U.S.N.M. J),
Stegosaurus stenops. Type. Cat. no. 4934, U.S.N.M.
All FiGintES
natural size.

Fig. 60.

Ttpe.

^

(See

probably transmitted a blood vessel supplying nourishment tocells, which, as shown by various cross-sections, is very cancellous, impljdng a bone
The spines gradually taper, except in S. longispinus, from theof light weight.
expanded bases to the subacute apex, the lower two-thirds being characterized bysharp edges fore and aft; but in many of the specimens the upper third is
subcircular in cross-section (fig. 59, c). Like the flat plates, the external surfaces
are covered by vascular impressions (pis. 16 and 17).
The anterior pair in all instances give evidence of having been more deeply
embedded in the skin than the posterior pair. That these spines were often
broken or injured in fife is shown by three specimens, two of which have the top/, fig.

65.)

It

:

,

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

96

broken off and healed, while the third (No. 6646) appears to have suffered otherinjury, as shown by the curved and thickened condition of the shaft.
The bases of the posterior pair in an articulated tail, as shown by two individuals (pis. 15 and 16),' would be subadjacent to the seventh, eighth, and ninth
caudals, counting back from the tip of the tail, while the anterior pair wouJd be
above the twelfth, thirteenth, and fourteenth vertebrae.
The relative difference in length between an anterior and posterior spine of
the same individual is shown in the table of measurements below
Measurements of spines.

Greatest length.

Anterior
spine.

Posteriorspine.

mm.
635

522

598

577

446

384

300

280

Arrangement op the Armor.

The most striking fact concerning the arrangement of the armor and one convincingly demonstrated by this specimen (No. 4934) is that the plates of opposite
but those of one side alternate with those of theThis feature has been the subject of considerable speculation andsides are not arranged in pairs,

other (pi. 14).^

discussion among vertebrate paleontologists and is one upon which directly opposite

views are held.
Marsh, in 1891, made the first pictorial restoration^ of Stegosaurus (pi. 32, upper
figiure) and placed the series of plates in a single row along the median hue of theneck, back, and tail, with four pairs of spines near the end of the tail. Lucas, in 1 901
published the next restoration,^ and was the first to show the plates arranged inpairs (pi. 33, lower figure).
Later, in a statuette prepared under his direction, theplates were made to alternate along the back and the caudal spines were reduced
from fom- to two pairs.
(See pi. 34, lower figure.)
The latest conception, as exemplified by a recently mounted skeleton ^ in the
Peabody Museum of Yale University (pi. 36, loyer figure), reconstructed under the
direction of Prof. E. S. Lull, and a small model of the animal in the flesh has
been made after this mount (pi. 36, upper figui-e)." In this a return to the paired
1

The positive evidence given by specimens in the National Museum as to the proper position of the spike-like spines near

the end of the tail in Stegosaurian dinosaurs would indicate that Nopcsa was in error in placing similar spines of Stegosaurus
priscus in an upright position on the scapular region of that animal.

(See F. Baron Nopcsa, Geol. Mag., vol. 8, No. 4, 1911, p. 152.

fig. 9.)was the first to recognize this arrangement. In his Animals Before Man in North America, 1902, p. 171, he saysof the plates; "They were placed far enough apart to permit freedom of motion and appear to have been arranged alternately
and not in pairs."
3 Amer. Joum. Sci., vol. 42, 1891,
pp. 179-181, pi. 9.
2 Lucas*5

Animals of the Past, 1901 fig. 24.
Amer. Joum. Sci., vol. 30, 1910, pp. 361-377, figs. 2, 3, and 4.
Idem, pi. 11.
,

—

OSTEOLOGY OF THE ABMOKED DINOSAXJKIA.

97

arrangement of the plates is shown and the original idea of four pairs of spines
retained.

The type of Stegosaurus stenops (No. 4934) corroborates most conclusively Lucas's
interpretation of the arrangement of the dorsal armor, and, except in one or two
points, I would indorse his restoration (pi. 34, lower figure) as being in accord mth theevidence shown by the specimens in the United States National Museum collections.
The reasons given by I^ucas for the alternating position, as stated in an unpublished manuscript, were twofold: First, that the plates did alternate as they lay

embedded in the rock, and, second, that no two of them were precisely similar in
Opposed to this argument. Lull has advanced the opinion

shape or dimensions.

' that the position of the plates in the rock is hardly conclusive, for the series might

easily have shifted forward or backward slightly during maceration or in the sub-sequent movement of the rock."
A careful study of this series of plates leads to the belief that such a shifting
has not taken place. For example, part of this series, as shownin plates 2, 4, and 14, has fallen to the left and lies under the
body of the animal, while the posterior plates are approximately in position above the pelvic region, yet both sections
show the same alternating arrangement. Moreover, there is aremarkable mriformity of the overlapping of plates of one side
upon those of the opjDosite row that is, the middle point of
the underlying plates, taken longitudinally, is, in neaiiy all
instances, in the center of the interspace between the plates of
the uppermost sei-ies (pi. 14). This exact spacing of the plates
would indicate that they remamed attached to the skin imtil
becoming fixed in the position in which we now see them.
If this be true, it is difficult to explain the possibifity of—bringing the plates of opposite sides into afignment, since in

Fig. 61.— Section of thewould be necessary to shift the smaU anterior ones only a few inches, while the larger plates would need
Certainly, if remaining attached
to be moved a foot or more.

NECK OF StEGOSAOHUS.

order to doso, itpi,

DERM.iL plate;r,

CERVICAL EIB; T, VEK-

tebka. Modified
FEOM Lull.

to the skin in sequential order, as the evidence appears to show,

had the plates of one side shifted, all would have moved in the same direction andapproximately similar distances.

As to the argument that the shifting took place by the movement of the rockthat view seems absolutely untenable, since nowhere, either in the specimen or
in attached rock, is there any indication of lateral shearing.
This specimen is surely another example of the truth so aptly put by the
Beecher when he observes that "the positive information
conveyed by the finding of a foot or of any other portion of a skeleton, with the hones
in a sequential position in the rock, is offar greater anatomical value than any number

late Prof. Charles E.

'of expert opinions."
That the bases of the plates of opposite rows, anterior to the sacrum, were
nearer together on the median line of the back (fig. 61) than has been represented
in any of the restorations of Stegosaurus is indicated1by the evenness of the bases

Trans. Conn. Acad. Sci., vol. 11, 1902, p. 311.

UNITED STATES NATIONAL MUSEUM.

98

shown in plate 14. Had there been considerable
space between them in folding back, the plates of one side would have their bases
projecting beyond those of the other, adistance approximately equal to thespace between the bases in life.
of the plates of No. 4934, as

The internal lip of the transversely
expanded bases of the plates of opposite
rows on the neck and anterior dorsal region, in specimen No .4934, appear to haveoverlapped the median line of the backas shown in figure 61.
In other words,
the expanded portion of the plates of one

row are in the center of the interspaceof those of the opposite side, so that theFig. 62.— Section of

POPHYSIS;

BEA.

Tpl,

the trunk of STECosAintus. i, DiaDEEMAL PLATE; r, BIB; S, SPINE; V, VEETE-

MODIFIED FEOM LULL.

point where the plates emerged from thethick skin of the back must have been butvery little off the middle line of the back.
The eAddence in favor of an erect
rather than a procumbent position for the

Fig. 63.— SECTION of

OF Stegosaurus.

the proximal paet of the tau.
Chevron; pZ, DEEMAL plate; «,MODIFIED FEOM LULL.

c,spine; V, VERTEBRA.

shown by the fact that both surfaces are covered with blood-vessel
impressions and no indication of either having been in contact with the creature's
plates, isOSTEOLOGY OP THE ABMOEBD DINOSAURIA.
flesh.

99

On the other hand, the base is extremely rugose and the only part adapted

Furtherfor insertion in the skin or for the attachment of other connective tissues.
more, specimen No. 4934 shows (pi. 2) the plates above the pelvic region retainedin the rock in such an erect posture, while those more anteriorly are folded backimderneath the skeleton, a thing manifestly impossible in plates natm-aUy pro-

cumbent on either side.
The rugose character of the bases of the plates, as well as of the spines, implies
an extremely tliick skin in which these were embedded. The ossicles, plates, andspines are all strictly dermal structures, for in no instance is there indication of
The vasicular grooves and impressions whicharticulation with subadjacent bones.
mark the surfaces of both plates and spines indicate that they were inclosed by ahorny covering wliich in life would
somewhat increase their size, as shownin figures 61, 62, 63, and 64.
The primary function of this armor
must have been that of defense, not,perhaps, in the sense of use as actual
defensive instruments, but protective
to the extent of giving the animal a

most formidable

appearance.

Itistrue that the spines near the end of

the tail may have been of some use
as defensive weapons, but they could

Fig. 64.—Section of distal poexion of the tail of Stegosaurus. S, Dekmal spine; V, veetebka. Modified feom

Lull.

have been of comparatively little value
chief
for offensive purposes, although it has been contended that this was their
To be effective in such a capacity, the tail should be flexible to afunction.
considerable degree, and tliis does not appear to have been the case. In thethe caudal vertebrae are joined by closely fitting zygapophyses, which
ends ofare present nearly to the distal end of the tail; moreover, the articular
the centra are rather abruptly truncated, not rounded or beveled, as in thoseanimals having a flexible tail. These structural details, combined with the series
Stegosaurus a heavy,of plates along the dorsal side, must have made the tail of
cumhersome lateral movements and wholly
stiff appendage, incapable of more thanfirst place,unsuitedfor use on an active enemy.
The facts relating to the dermal armor which now appear to be establishedfrom this study of the Stegosaurian remains in the United States National Museum
back, and tail was formed by two rows of erect plates, the ele(1) That the armor of the neck,ments of one row alternating with those of the other.
plates in the two rows was not less than 20 and not more than 22.
(2) That the total number ofplate of the series appears to be above the base of the tail and(3) That the position of the largest

not over the pelvis.
dermal spines on the tail is four, arranged in two pairs.
(4) That the usual number of

:

.

.

.

.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

100

Measurements of dermal plates of Stegosaurus stenops No. 4934-

Greatest
lengthantero-Greatest

diameterantero-posterior

width

Plate
No.
(countingback-posteri-of rough-or rough-

ward

orly.

ened

ened

from the

base.

base.

skull).

mm.

mm.

36

17

Plate

No.
(counting
back-

ward

Greatest
Greatestheight.

Irom theskull).

inm.

mm.

'1

97

60

2

119

45

3

134

82

4

172

5

185

6
7

8
9

2

trans-

10

76

55

76

60

191

96

2 323

205

430

ISO

105

•

of rough- of rough-610+trans-

verse

width

ened,

ened

base.

base.

mm.

mm.

423

40

535
560

12

610

590

55

695

590

14

760

785

720

87

3

15

627

630

450

105

3

16

335

410

300

=

17

225

290

220

60

<18

537

U5

65

Plates with, odd numbers pertain to left row. even to the right row.

2

Estimated.

8

Dermal elements not in sequence.
Dermal spine.

*posteri-

11

13

610+

antero-diameterorl}'.

2

Greatest

Greatest
lengthanteroposteriorGreatest
Greatestheight.

Type.

Position of -plate centers in relation to underlying vertebrae.

Plate

Plate

Plate

No.

No.

No.
(countingback-(countingback-Vertebrae in vertebral
column.

ward

ward

Vertebrae in vertebral
column.

(counting
back-

ward

from thefrom thefrom theskull).

skull).

skull).

Vertebrae in vertebral
column.

1

Atlas.

6

Sixth and seventh (between)

10

2

Axis.

7

Eighth.

11

3

Third and fourth (between)

8Tenth.

12

Twenty-fourth.

4

Fourth and fifth (between).

9

Thirteenth and fourteenth

13

Second caudal.

5

Fifth and sixth (between)

14

Eighth caudal.

(between)

Seventeenth.

Twentieth.

Morphology of Plates.

has given the following interesting explanation of the development ofLull
the dermal plates'Upon comparing a given plate with a scute of a crocodile or that of such a dinosaur as Ankylosaurus
or Stegopelta it at once becomes apparent that the great expanse of the first represents merely an enor-

mous hypertrophy of the median ridge or carina of the latter. This expanse is practically alike on bothsides, with blood-vessel impressions and no indication that either one side or the other was in contact
with the creature's flesh. On the other hand, the base, the morphological equivalent of the body ofthe scute in crocodile or Anhylosaur, is always somewhat asymmetrical, even when divided into twoThis base in the great dermal plates
portions by the longitudinal cleft of those of the cervical region
particularly is extremely rugose, implying either a heavy pad of cartilage or a very thick connective
There is in no instance any indication
tissue between the plate and its underlying skeletal support.
.

of a true articulation with the subadjacent bones.
1

Amer. Joura. Sci., vol. 29, 1910, pp. 204-205.

OSTEOLOGY OF THE AEMOEED DINOSAXJRIA.

101

THE GENUS STEGOSAUEUS.
In a paper published in 1877 ^ Prof. O. C. Marsh proposed the genus and species
Stegosaurus armatus, referring it to the new order Stegosauria, which was notdefined.

In 1878,^ Prof. E. D. Cope, on meager material, proposed the genus Hypsirophus
and briefly described the species H. discursus, and in 1879 ^ described a second
species, \S'. seeleyanus.
Both of these species were based upon specimens from theJurassic of Colorado and later were referred by Marsh and other authorities to thegenus Stegosaurus.
In 1879 * Marsh briefly described the species S. ungulatus. In 1880,^ without
comment, he refers to the Stegosauria as a suborder and for the first time defines
the genus Stegosaurus as follows:(1) All the bones of the skeleton are solid.
(2) The femur is without a third trochanter.
(3) The crest on the outer condyle of the femur, which in birds separates theheads of the tibia and fibula, is rudimentary or wanting.
(4) The tibia is firmly coossified with the proximal tarsals.
(5) The fibula has its larger extremity below.
Marsh briefly described the skull, brain, limbs, dermal spines, and plates.
Teeth were also described, but were afterwards ° discovered to pertain to the Sauro-

pod dmosaur Diplodocus.
In Februaiy, 1881,' Marsh recorded additional information concerning the
In the same communication the species S. affinis
brain, pelvic arch, and limbs.
was named, but inadequately defined. In a paper piiblished in May of the same
year ^ the following classification was proposed by him for the genus Stegosaurus:
Suborder Stegosauria.

Family Stegosauridse.
Genus Stegosaurus.
In 1882,° Marsh again raised the rank of the Stegosauria to an order and at
the same time defined it, placing under it two families, the Stegosauridse and the
Scelidosauridse.

His definition is as follows:

Order STEGOSAURIA
ungulate; five digits in manus and pes; second row of carpals
Pubes projecting free in front; postpubis present. Forelimbs very small; locomotion
mainly on hind limbs. Vertebrae and limb bones solid. Osseous dermal armor.
Vertebrae biconcave. Neural canal in sacrum expanded into large(1) Family Stegosauridse.
chamber; ischia directed backward, with sides meeting on median line. Astragalus coossified with

Herbivorous;

feet plantigrade,unossified.

metapodials very short.
Genera: Stegosaurus [Hypsirhoplms), Diracodon, and, in Europe, Omosaurus Owen.
Astragalus not coossified with tibia; metatarsals elongated; four(2) Family Scelidogauridse.
functional digits in pes. Known forms all European.
tibia;

Genera: Scelidosaurus, Acanthopholis, Crataeomus, Hylaeosaurus, Polacanthus.
Amer. Joum. Sci., vol. 14, 1877, p. 513.
American Naturalist, vol. 12, 1878, pp. 188, 189.
Idem, vol. 13, 1879, pp. 401, 402.
< Amer. Joum. Sci., vol. 18, 1879, p. 604.
5 Idem, vol. 19, 1880, pp. 251-259, pis. &-V
1

Amer. Joum. Sci., vol. 26, 18S3, p. 85.
Idem, vol. 21, 1881, pp. 167-170, pis. 6-8.
Idem, vol. 21, 1881, p. 423.
' Idem, vol. 23, 1882, pp. 83, 84.

'

2

'

3

'

51873°— Bull. 89—14

8

:

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

102
In 1884 'this classification

was republished, without change except in thedefinition of the order the additional character "cervical ribs free" was inserted.

In 1887 ^ the discovery of additional specimens enabled Marsh to contributeand dermal armor. In the same paper
the tliree new species Stegosaurus stenops, S. sulcatus, and S. duplex were briefly
designated. The close relationship of tie Stegosauria with the Ornithopoda wasrecognized and a list of important characters wherein they differ was given.
further to the knowledge of the skull

The first restoration of Stegosaurus was published by Prof. Marsh in 1891 ^and additional characters relating to the osteological structure and life appearanceof the animal were noted.

In 1893

Lydekker republished Marsh's restoration of Stegosaurus and inadit to the genus HypsiropTiUs.
Later in the same publication(p. 438), Marsh calls attention to this error.
In 1895 ^ Marsh published a revised definition of the Stegosauria, here again
With a few emendations these definitions were repeated incalled a suborder.
1896 ° in his Dinosam's of North America.
In 1900 ^ Lydekker referred the two British species Omosaurus aimatus and 0.
''

vertently referredhastiger to the genus Stegosaurus quite oblivious of the fact that the genus alreadycontained an American species S. armatus.

Lucas in 1901 ° described the species

8. marshi and in the foUomng year it was referred by him to the new genus Hop-

Utosaurus,^

and in the same article the generic name Dacentrurus was proposed

for Owen's genus Omosaurus, preoccupied.

In the same year Lucas ^° contributed further to oiu" knowledge of Stegosaurus,
particularly as to the life appearance of the animal, presenting a restoration by

Charles E. Knight.

In 1902 " Hay created the superfamily Stegosauridea and under the genus
Stegosaurus the following species were recognized: S. affinis, S. armatus, S. discursus,
S. duplex, S. seeleyanus, S. stenops, S. sulcatus, and S. ungulatus.

In that year Lucas '^ announced for the first time the "probable" alternating
arrangement of the dermal plates of opposite rows.
Zittel " defined the genus Stegosaurus thus
Skull narrow and depressed, relatively very small, and brain cavity in proportion to size of the
body more dimiaiitive than in any other land vertebrate. Orbits small; laterally directed; supratemporal vacuities small and rounded; nasals nearly half as long as the slcull. Mandibular ramus deep,
pierced by a lateral foramen. Teeth very numerous, bluntly pointed, more or less spatulate in form,
loosely socketed in a single functional series.

Vertebrae slightly amphicoelous or with flat ends, thecervicals with short ribs and dorsals with much elevated neural arches, on which the stout dorsal ribs
1

2
3

Nature, vol. 31, 1884, p. 68.
Amer. Journ. Sci., ser. 3, vol. 34, 1887, pp. 413^17, pis. 6-11.
Idem, ser. 3, vol. 42, 1891, pp. 179-181 with pi. 9; also Geol. Mag., ser. 3, vol. 8, 1891, pp. 385-387, pi. 10.

8Nature, vol. 48, 1893, p. 304, fig. 3.
Amer. Journ. Sci., ser. 3, vol. 50, 1895, pp. 496-497.
leth Aim. Rept. U. S. Geol. Surv., pt. 1, 1894-95.

'

Cat. of Fossil Reptiles and Amphibia, vol. 4, 1900, p. 252.

<5

8 Proc.

U. S. Nat. Mus., vol. 23, 1901, pp. 591,692, pis. 23,24.

9 Science, vol.

16, 1902, p. 435.

Animals of the Past, 1901, pp. 106, 107, fig. 24.
" Bull. 179, U. S. Geol. Survey, 1902, pp. 495, 496.
" Animals before Man in North America, 1902, p. 171.
13 Text-book Paleontology, English Translation, vol. 2, 1902, pp. 241, 242.
10

OSTKOLOGY OF THE AKMOEED DINOSAUBIA.
are borne.

103

Sacrum of four fused vertebrae, sometimes with oue or more lumbara added on in front;

thin neural canal enlarged to ten times the capacity of brain cavity. Anterior caudal vertebra thelargest in the column, and with strong chevron bones.
Forelimb short and stout, ulna with large
olecranon process. Manus short, apparently pentadactyl. Femur large and straight, without inner
trochanter; tibia and fibula much shorter.

Astragalus and calcaneum fused with opposing bones of the
cms; pes tridactyle, digit No. I rudimentary and No. V wanting. Dermal armour consisting of two
rows of flattened bony plates extending from the back of the head well down the tail, the largest plates
situated immediately over the pelvis. Four spines on the tail, and throat protected by a shield of
irregular ossicles.

In 1910 ' Lull contributed an article on the Armor of Stegosaurus, in which
he concluded that the plates were arranged in two rows, but in pairs. Later, inthe same year,^ he pubhshed a picture of the first mounted skeleton of the genus
and a life restoration based upon the mount. The actual assembling of the bones
brought about several changes from the previously accepted conceptions of theanimal.
It was also shown that the species S. duplex is not vahd, and that the
type-specimen of that species is one of the cotypes upon which Marsh founded
the species S. ungulatus.
Zittel,' in 1911, included all of the armored Dinosauria under the family
Stegosauridse and redefined the genus Stegosaurus.

As shown by the recent study of the extensive collection of Stegosaurian
remains in the United States National Museum, the earher definitions of the genus,
as biiefly reviewed above, are in several respects in error.
Such inaccuracies as
have been detected can be attributed in most instances to the incompleteness ofthe material at the command of the earher authors.
In the Hght of new and better preserved specimens, the genus Stegosaurus
may now be characterized as follows:
Generic characters.

— Skull relatively very small and brain cavity

in proportion

to size of the body more diminutive than inbital region

foramen.

composed

Dentition

of

23 4-

^

.

any other land vertebrate. Supraortwo separate bones. Ramus deep and without lateral
Teeth extremely small and weak.

Vertebrae slightly

amphicoelus, or with flat ends; dorsals with much elevated neural arches.

canal in sacrum enlarged tomany times the capacity of the brain.

Neural

Sacrum andby bone. Anterior caudal vertebra largest
Ulna (in adults) as long as humerus, with large olecranon process.
pentadactyle.
Phalangial formula of digits III and IV apparently

lateral processes entirely roofed overin the column.

Manus short,
Femur long, straight, fourth trochanter vestigal, with or without lesser
trochanter.
Tibia having greatest diameter of two ends in the same plane.
Pestetradactyle, digit IV consisting of a vestigal metatarsal, digit V wanting.
Dermal armor consisting of two rows of erect, flattened plates extending fromreduced.

back of head to distal fourth of tail. Plates of opposite rows alternating. Fourdermal spines near end of tail.
Stegosaurus armatus is the type-species of the genus, and was founded upon a
specimen from the Morrison beds near Morrison, Colorado. Fourteen species have
1'*Amer. Joum. Sci., vol. 29, 1910, pp. 201-210, flgs. 1-11.
Idem, vol. 30, 1910, pp. 361-.377, flgs. 1-10.
Grundziige der Palaeontologie, vo). 2, 1911, pp. 293-295.

——

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

104

been referred to this genus, ten of which are American and four European. Of
these, one appears to be a nomen nudum, one is a synonym of a species ah-eadydescribed, and three others have been referred to other genera.
Now only nine
vahd species are recognized, and a revision of these will probably bring about afurther reduction.

An alphabetical list of the species, location of the type, and its catalogue number is given below:
Stegosaurus affinis Marsh, 1881 (nomen nudum) (Yale University Museum).
Stegosaurus armatus Ma-rse, Dec, 1877 (No. 1850, Yale University Museum).
Stegosaurus {Oiriosaurus) armatus (Owen), 1876 (No. 46013, Britisli Museum) =2>ace?i<ran(s armatus(Owen).
Stegosaurus (Hypsirophus) discurus (Cope), Mar., 1878 (Amer. Mus. Nat. Hist.).
Stegosaurus duplex Marsh, Nov., 1887 (No. 1858, Yale University Museum) =fS'. Mnsrufaius.
Stegosaurus durobrivensis Hulke (Britisli Museum).
Stegosaurus (Omosaurus) hastiger (Owen), 1877 (Nos. 46320, 46321, 46322, Britisli Museum) =Z)acentrurus hastiger (Owen).

Stegosaurus longispinus Gilmoke, 1914 (No. D54, Univ. of Wye).
Stegosaurus marshi Lucas, Feb., 1901 (No. 4752, U. S. Nat. Mns.)=HopUtosaurus marshi (Lucas).

Stegosaurus priscus 'SoFcsA, Mar., 1911 (No. R. 3167, British Museum).
Stegosaurus (Hypsirophus) seeleyanus (Cope), June, 1879 (Amer. Mus. Nat. Hist.).
Stegosaurus stenops Marsh, Nov., 1887 (No. 4934, U. S. Nat. Mus.).
Stegosaurus sulcatus Marsh, Nov., 1887 (No. 4937, U. S. Nat. Mus.).
Stegosaurus ungulatus Marsh, Dec, 1879 (No. 1853-1858, Yale Univ. Museum).

Description of Species.

,|

With one exception the following descidptions are based on type-specimens in
the United States National Museum. The reference to the original description isfollowed by citations of the more important literature which further elucidates the
species under consideration.

The parts of the skeleton constituting the type are listed, and the locality,
and catalogue number are given in eachgeological horizon, name of the collector,

case, so that a permanent record of the type material will hereafter be available.

In the discussion of the species the original description will be quoted in its
entirety, followed by a historical account of the specimen and a further descriptionof such parts of the skeleton as seems necessary to supplement the original text.

STEGOSAURUS STENOPS Maish.
Plates 2-9 and 11-17, 19; 22, fig. 3; 23, figs. 2, 3, 4, 6; 24.

Stegosaurus stenops Marsh, Amer. Journ. Sci. (3), vol. 34, 1887, pp. 414, 415, pi. 6; Geol. Mag. (3),vol. 5, 1888, pp. 11-15, pi. 1.
Ltdekker, Cat. of Fossil ReptUia and Amphibia in the British
Museum, pt. 1, 1888, p. 176, fig. 31. Zittel, Handbuch der Palaeontologie, vol. 1, 1890, p.
654.—
Marsh,
figs.
Amer.
Journ. Sci (3), vol. 39, 1890, p. 426, pi. 7, fig. 2; vol. 42,
650,
745,
1891, p. 179.— Cope, Trans. Amer. PhUos. Soc, vol. 17, 1892, p. 18 (Hypsirophus ).—Marsh,
16th Ann. Rept. U. S. Geol. Siu-v., pt. 1, 1896, p. 186, pis. 43 and 47, fig. 3; Mon. 27, U. S.
Geol. Surv., 1897, p. 499, fig. 52.—Woodward, Outlines of Vertebrate Paleontology, 1898, p.
212, fig. 131.—NopcsA, Foldtani K6zl6ny, Budapest, vol. 31, 1901, p. 215.—Hat, Bull. 179,
U. S. Geol. Survey, 1901, p. 496.— Lull, Amer. Journ. Sci., vol. 29, 1910, pp. 206, 208; vol. 30,

1910, p. 373; Verhandlungen des VIII. Internationalen Zoologen-Kongresses zu Graz, 1910,
Grundzuge der Palaeontologie, pt. 2, 1911, p. 293, fig. 442.—Huene, Neuea
Jahrbuch, vol. 37, 1914, pp. 580, pi. 10.
Biracodon laticeps Marsh, Amer. Journ. Sci., vol. 24, 1887, p. 416, pi. 9; Geol. Mag. (3), 1888, pp. 11-15,
pi. 3; 16th Ann. Rept. U.S. Geol. Surv., pt. 1,1896, p. 193, pL 51. (Not X>. Zaiiceps Marsh, 1881.)
p. 677.— Zittel,

:.

OSTEOLOGY OF THE AKMOKED DINOSAUEIA.
Type-specimen.
lated skeleton.

—Cat. No. 4934, U.

S. N. M.

105

A comparatively complete articu-

The parts preserved are listed below.

Two

Skull.

Lower jaws.

phalanges(proximalrow

digits III, IV, left fore foot).

One carpus (left).
One radiale (right).

Atlas.

Axis.

Three metacarpals (right).
Five ? phalanges (right).

Twenty-five presacral vertebrae.

Three sacral vertebrae.
Twenty-two caudal vertebrae.
Five cervical ribs.
Twelve thoracic ribs (right).

Two femora.
One tibia (right).
One fibula (right).
One astragalus (right).
One calcaneum (right).

Thirteen thoracic ribs (left).
Four chevron.
One scapula (left).
One coracoid (left).

Two ilia.
Two ischia.
Two pubes.

Two humeri.
Two ulnae.
Two radii.
Four metacarpals(II,

III, IV,V

Seventeen dermal plates.
One dermal spine.
Numerous dermal ossicles.

of left fore foot)Collected by M-. M. P. Felch, 1885-1886.
Type-locality.

Colorado.

—Quarry No.

1,

Garden Park, near Canon City, Fremont County,—

Horizon. Morrison, Upper Jurassic.
The original description, by Marsh, is as f oUows

The skull of SUgosaurus is long aud slender, the facial portion being especially produced.

Seenfrom the side, with the lower jaw in position, it ia wedge-shaped, with the point found by the premaxUlary, which projects well beyond the mandible. The anterior nares are large and situated far in front.
The orbit is very large and placed well back." The lower temporal fossa is somewhat smaller. All
these openings are oval in outline and are on a line nearly parallel with the f»p of the skull. In thisview the lower jaws cover the teeth entirely.
Seen from above, the wedge-shaped form of the skull ia still apparent. The only openings visible
are the supratemporal fossce. The premaxillary bones are short above, but send back a long process
below the narial orifice. The nasal bones are very large and elongate. They are separated in front by
the premaxillaries and behind by anterior projections from the frontal bones. The prefrontals arewith each
short and externally join the postfrontals. The parietals are small and closely coossified

Viewed from in front the skull and mandible present a nearly quadrate outline [pi. 9, fig. 1]
and the mutual relations of the facial bones are well shown. In this view is seen also the predentarybone is shown
bone, a characteristic feature of the mandible in this genus. The lateral aspect of thisThe teeth in this genus are entirely confined to the maxillary and dentary bones[pi. 5].
in figureother.

and are not visible in any of the figures here given. They are small, with compressed, fluted crowns,
which are 89parated from the roots by a more or less distinct neck. The premaxillary and predentarybones are edentulous.

The present skull belongs to the type-specimen of a new and very distinct species, which may beof this specimen, with nearly aU
called Stegosaurus stenops. The skull and nearly complete skeleton
animal died.
the dermal armor in place, were found in almost the position in which theIts remams
speciesof this genus.
the
other
This animal was much smaller than those representing
in southern Colorado.
Jurassic,
the
Upper
of
beds
Atlantosaurus
theMr. M. P. Felch, inwere found by

In this geological horizon all the known American forms of Stegosaurus

have been discovered.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

106—

History of the specimen. The skeleton was collected by Mr. M. P. Felch during
the years 18S5 and 1886 from quarry No. 1 (pi. 1, lower figure) in Garden Park,
Fremont County, Coloi'ado. That Mr. Felch recognized the importance of thespecimen is clearly shown by the carefully made diagrams, notes, etc., which heprepared in order to facilitate the fitting together of the blocks of sandstone andbroken pieces when it should be assembled in the laboratory.
The specimen was shipped to Prof. O. C. Marsh at New Haven, Connecticut,
where it was partially assembled and the rock covering was removed from what

was the lower side in the quarry, as shown in plate 4. The skull was the only
part worked out free from the matrix. In this condition the specimen was studied
and in 1887 briefly described by Prof. Marsh as the type of the species S. stenops.
It was then sent to storage, where it remained until after the death of Professor
Marsh. In 1899 all of the vertebrate fossils at New Haven belonging to the Government (comprising five carloads) were shipped to the United States National
Museum, the present specimen forming a portion of that collection. In 1904, under
the direction of Mr. F. A. Lucas, the specimen was unpacked and sufficiently assembled to obtain the necessary data for the life restoration made in that year by
Mr. C. R. Knight (pi. 33, lower figure). The drawing of the dermal plates shown in
It was again placed in storage and remained
plate 14 was also made at that time.
So that now,there until September, 1911, when its final preparation was begun.
after a period of 28 years since it was first discovered, this most perfect specimenof a Stegosauru-s is at last available for exhibition and study purposes, and it willlong serve as a standard for interpretating and coordinating the scattered parts of'others of its kind.

—

Position of the slceleton. The specimen as assembled and as now exhibited in
the United States National Museum (pi. 2) shows the skeleton in the position it
occupied in the quarry. Every bone occupies the precise relative position it did
when found. In order to show the series of dermal plates that were folded backbeneath the body of the animal a large mirror was installed in such a manner as to

A second mirror was likewise placed below
the overturned skull, so that it reverses the head to its normal position and at
the same time shows the elements comjiosing the top of the cranium.
The adaptation of mirrors to the better display of large fossil specimens, here
display these ])lates to the observer.

used for the first time, is most gratifying in the results obtained.
When the skeleton was found it lacked the greater portion of the posterior
The animal lies on
half of the tail, the hind feet, and some other minor portions.
its left side^ with the bones so closely connected that there can be no question
raised as to their belonging to this one individual.

The vertebral column is largely intact and to -a great extent articulated— atleast it is so little disturbed that the axial skeleton appears to be complete fromthe tip of the nose to the seventeenth caudal. The distal half of the tail, as men-tioned above,islargely missing, although five caudal vertebrae, thi-ee plates, andAmer. Journ. Sci., vol. 34, 1887, pp. 414-H.'i, pi. 6.
= In a letter to Professor Marsh, dated June 23, 18S6, Felcli says:
The animal here lay on its left side and up against the bank of our old river bed, bringing its left [right) hip the highest, theright [left] hip and some bones having slid downhill toward the bottom of the bed. Most all of the plates along here lay up
and on the outside of this bank, resting on the marl bed.
1

107

OSTEOLOGY OF THE ABMOEED DINOSAUEIA.
one of the dermal spines are scattered about beyond the last of theseries.

(See pi. 2.)

articulated.

The presacral vertebrae, with the exception of the mid-dorsal region, retam
In the middle of the series three vertebrae have been
their relative positions.
is suffipushed up and out of position, but the combined length of these vertebrae
articulated series. This
fill the gap between the posterior and anterior
indicate that none are missing. The head and neck are articulated
would appear
death-likeand curve backward toward the fore feet, lying ventral side up in a
The femora are nearly in place in the acetabulum with their distal ends
attitude.
leg iswide apart as if at the end of a long stride. The tibia and fibula of the rightlower limb
doubled back along the front of the femur, but the foot as well as theconsiderable
bones of the left leg are missing. Both articulated fore limbs, with
one lying on top of the)>ortions of both fore feet, occupy their relative positions,
The thoracic ribs of the right side have been pushed up into a heap alongother.
cient tot(.'of the vertebral column.
the front of the right ilium and above the posterior portion
relative positions, their freetheirinretainedlargely
areside
opposite
the
of
Those
and to some extent showing the natural curve of this portion

ends curving ujwardof the body cavity.

The pelvic bones are all present, though slightly disarranged; the ilia, however,remain firmly coossified with the sacral vertebrae and show plainly

the great breadthof the hips.

The dermal plates, which in life stood erect along the back, are present to atheir mutual relationsMps.
point back of the pelvis and are retamed in the rock inanimal are turned
The eleven plates forming the armor of the anterior part of theof bone upon which
sheet
continuousaforming
neck,
and
body
the
back in underlarge plates over and back of thethe anterior parts of the skeleton lay. Threeduring, the fife of the animal, theirsacral region occupy much the same position as
associated vertebrae. There arebases being just above the spinous processes of thementioned above, and althoughasregion,caudalthefrompresent
platesthree other
The little disposteriorly.
disarranged they show the relative decrease in sizethat it was found in a placeturbed condition of the specimen appears to indicate
position is that of an animal
not far removed from where the animal died. The
as exists can be attributed
disarrangement
suchfor
death,
natural
a
died
which
than to their having been torn apartto the natural shifting of the bones rather
by any of the contemporary carnivora.
entombment of this specimen, as readTTieoni offossilization.—The story of thewould appear to be as follows:from the position of the various parts of the skeleton,
one of the large streams that
of
banks
the
along
or
water
the
in
died
The animaldays.
traversed that portion of Colorado in those ancient

In the event of death

set in a freshet floated thehavmo- occurred along the banks, before decomposition had
water subsided was stranded upon
carcase's and it was carried downstream, and, as thetissues commenced to relax and
soft
the
bar
the
reaching
Beforebar.
an old river
comingplates along the top of the back to droop, and uponaUowed the projecting
the current acting
mto shallow water their points were caught in the sand andthem back underneathagamst the carcass forced it over and upon the plates, foldingof the series, those above the hips
the ribs of the lower side. The larger plates

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

108

and base of the tail, which were doubtless" most strongly attached, retained their
As decomposition progressed the other bones of the skeleton
either settled into the sand, as is true of those of the lower or left side where theribs of the body are found spaced much as in life, while those of the right side havebeen carried into a pile above the backbone and against the upstanding hip bones.
That these elements were piled up by the action of the current appears to be indicated by the fact that the longer axes of the bones of this side aU lie in the samegeneral direction. In other words, the direction of the force of the current was
diagonally across the longer dimensions of the skeleton, as indicated by an arrowon the diagram (pi. 3). Thus were the bones laid down, and the filial part ofnatural positions.

the story necessitates a rapid covering of the skeleton by sand in order to make thecondition right for the petrifaction and preservation of the specimen. This sandin the many years following was covered by other sediments until many thousands

The great pressure brought about by the accumulatedof feet had accumulated.
weight of the overlying strata consolidated the loose sand into the hard sandstonethat untU recently completely enveloped the fossil.
Discussion.
Since this specimen is the basis for that part of the present paper
devoted to the osteology of Stegosaurus, where the skeletal parts have been described in detail, it is only necessary to discuss here those characteristics wherein
it differs from the other known species.
On account of the inadequate descriptionsof the type-specimens upon which the other American species are based and which
are preserved elsewhere, I am unable to contrast these species to the best advantage,
but such differences as have been found appear to indicate that other and more
important specific characters wiU be disclosed when those types are more fuUy
known and available for comparison.
Typically the skeleton of Stegosaurus stenops represents an adult animal of
medium proportions, being, less robust than the specimens upon which S. ungulatus and S. sulcatus are based.
From S. ungulatus this species may at present be
distinguished chiefly by characters found in the sacrum and femur.
In S. stenops the sacrals have a decided ventral keel, as compared with thebroad, rounded, keel-less centra of S. ungulatus; the nonparticipation of the caudosacral rib in the forrnation of the sacracostal yoke and the much shorter spinous
processes of the sacrals are other distinguishing characters.
The presence of a rudiinentary finger-Hke lesser trochanter (a, fig. 45) on the outer
anterior face of the proximal end of the femur of S. stenops, and its relatively shorter
length distinguish it at once from the slender, elongate femur of S. ungulatus where
the lesser trochanter has entirely disappeared.
(Compare 1 and 3, fig. 45.)—

From S. sulcatus this species may be distinguished by its smaller size anddifferences displayed in the dermal tail spines, as shown in figure 60.

The genus Diracodon•

was founded by Marsh upon two imperfect maxiUarybones (No. 1885, Yale University Museum). Later, from the study of additional
material, other characters were assigned this genus and a figure of the chstal endof the tail with spines in situ (No. 4288, United States National Museum) was pub^lished (pi. 15).
1Amer. Joiim. Sci., vol. 21, 1881, p. 421.

:

109

OSTEOLOGY OF THE AEMOBED DINOSAUBIA.

Marsh says of these specimens: "Aside from the form of the skull [meaning
maxillae] these specimens have in the fore foot the intermediun 'and ulnar bones
separate, while in Stegosaurus these carpals are firmly coossified." As shown by
specimens in the National Musevun (fig. 36), all small individuals have the intermediimi, ulnare, and pisiform separate, while in large individuals these are comAnother character assigned to Diracodon is the freedom of the astragpletely fused.
This is also an age characteristic, as
alus and calcaneiun from tibia and fibula.
abundantly shown by National Museum specimens. The caudal vertebrae and spines
ascribed to D. laticeps by Marsh (pi. 15) agree in shape and size with those belonging

From
to Stegosaurus, and are here referred to S. stenops (compare pis. 15 and 16).
upon thethis brief review it will be seen that this genus and species rests entirely
characters displayed by the teeth and maxillary bones, and these, accordmg to thedescription by Marsh, agree in nearly all respects with those of Stegosaurus. In
1902 Zittel's Text-book of Paleontology (vol. 2, p. 242) says: "Is probably foundedon the young of this species," referring to S. ungulatus. It appears that at thetime Diracodon laticeps was founded the homologous parts of Stegosaurus were
unknown, which would accoimt for Marsh's statement that the genus is mostnearly related to Laosaurus, and also for its reference to the Family Camptosau(Camptonotidse) an assignment corrected later.
Although I have not had an opportunity of examining the type-specimen, it
would appear that the genus, and probably also the species, are invaUd and shouldbe abandoned.
STEGOSAURUS SUtCATUS Marsh.
ridse

,

Plates 18; 20, figs. 3 and 4; 21, fig. 2; 23, fig. 1; 25, fig. 3.

Mag.,
Stegosaurus sulcatus Marsh, Amer. Jouru. Sci., vol. 34, 1887, p. 415, pi. 8, figs. 4-6; Geol.
Rept. U. vS. Geol. Survey, pt. 1, 1896, pi.
ser. 3, vol. 5, 1888, pi. 2, figs. 4-6; Sixteenth Ann.
50, figs.

4-6.—NopcsA, Foldtani Kozlony, Budapest, vol. 31, 1901, p. 215.— Hay, Bull. 179,

210,
U.' S. Geol. Survey, 1901, p. 496.— Lull, Amer. Journ. Sci., vol. 29, 1910, pp. 209,

Type-specimen.—Cat. No. 4937, U.S.N.M.

Consists of 4

fig.

11.

dermal spines, 2dermal plates (one pertaining to the neck, the other to the mid-dorsal region),
both scapulae,
right humerus, right ulna, two radii, both fore feet, portions ofCollected by Mr. J. L.
parts of femora, fibula, ischium, and caudal vertebrae.

Kenney in 1883.
Type-locality.—QiiurT J 13 near Como, vUbany County, Wyoming.
Morrison, Upper Jurassic.
This species has never been adequately defined, and it is only
Description.
study. Marshrecently that the type-specimen was assembled and prepared for
Horizon.

——confined his first observations to a study of one of the dermal spines of the anteTwo grooves or sulci (pi. 18, fig. 2) on the inner face suggested therior pair.

specific

name, but, as will be shown later, these grooves are not present on the

opposite spine, and this character, therefore, does not serve to distinguish
The original description is as follows

the species.

present evidence of only
In one large species, which maybe called Stegosaurus sulcatus, there is atand have two grooves on the inner
one pair of spines. These are the most massive of any yet found,known.
face, which distinguish them at once from all others

110

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

In some trays of unprepared material in the United States National Museum
there was found, together with other parts of the skeleton, three dermal tail spines,
one of which (b, fig. 65) bore a striking resemblance to the spine figured and describedby Mai-sh as the type of S. sulcatus, its chief difference from the type being theabsence of the "two grooves on the inner face." In the same tray was a box
label, on which was written, with other information, evidently by the collector,"four spines in this box." Since only three were found, it occurred to me thatperhaps the fourth might be the one described by Professor Marsh, and upon comparing the original labels foimd with each the above conclusion was verified. Bothlabels had the accession number |1650| ,and they also showed that all four of thespines had been packed in "box 8 " when shipped from the field.

This information,
together with the fact that of the 30 dermal spines now before me, there is only
one (this in the "box 8" lot) showing a resemblance to the type spine of S. sulcatusthrough the great development of the basal end.

There was also the additionaldermal tail spines of STEGOSAnEUS SULCATUS Maksh. Type. Cat. ho. 4937 U.S.N.M.
About -jV nat. size. Vie-wi;d feom the fkont. a, Type spine; b, spine kecentlt found; c, rugose surface foe
caetilagious uoton of the two spines above the caudals; /, foramen passing into inteeioe of spine; s, sulci,
PRESENT only ON EIGHT-H.AND SPINE.

Fig. 65.— Anteeiok pair ofevidence of this being the proper association of these bones from the fact thatthese two spines are opposites, as shown in figure 65.
The posterior dermal spineslack the greatly enlarged bases of the anterior pair, are without sulci (pi. 25,
fig. 3), and indistinguishable from those of an adult specimen of S. ungulatus.

The type of S. sulcatus is a large and evidently a very old individual. The
few bones of this specimen sufficiently complete to be compared with those ofother species show no good distinguishing characters except for their very large size,
so that for the present this species must rest upon the greatly expanded bases of theanterior pair of spines, and this feature may be found to be an age characteristic.
In that event tliis species would represent a very large and old individual of 8. ungulatus.
The sulci mentioned by Marsh and so plainly shown in plate 18, figures
2 and 3, are not present on the opposite spine, and in the Stegosauria this feature
is probably as inconstant as it has been found to be in the Ceratopsia, where sulci
are present on one supraorbital horn-core but absent on the other.
These spines
are fully illustrated in plate and text and further description appeai-s unnecessary.
The radius, foot, and ulna are shown in plate 20, figures 3A, 4A, plate 21, figure 2,
and nuchal plate in plate 23, figure 1, also in text figure 57.
\

OSTEOLOGY OF THE ARMORED DINOSAURIA.

Ill

Measurements of caudal spines No. 4937.
Anterior pair.

Right.

Posterior pair.

Left.

Right.

mm.

Left.

mn.
623

370

520

274

275

150

160

180

170

80

80

STEGOSAURUS LONGISPINUS, new species.

—

Type-Specimen. No. D54 Museum of
the University of Wyoming.
Collected by

W. H. Reed and Prof. A. C. Dart in 1908.

—

Type-locality.
About 14 miles east of
Alcova, Natrona County, Wyoming.

Horizon.

—Morrison Beds, Upper Ju-

rassic.

The type-specimen consists of 42 vertebrae from all parts of the backbone, fragmentary sacrum, two ischia, portion of one
pubis, right femur, several ribs and fourdermal tail spines, two of which are fairly
complete.
Distinctive characters found in the der-mal spines andposterior caudal vertebrae

make it necessary to create a new species,
and I therefore propose the name Stegosaurus longispinus, the specific name being
suggested by the slender elongated natureof the dermal tail spines.

Detailed description.

of S. longispinus
recorded.

are—The dermal spinesthelongest so far

The most complete spine of thefour present measures 860 mm. in lengthand the tip is missing. It is estimated thatthe complete length of this bone would be
about 3 feet 3 inches (985 mm.). This species is unique in the uniform development ofof deemal tail spines ofstegosaurus longispinus. type. d 54, university
OF Wyoming collection, j nat. size. (1) Lateral
VEEW; (2) posterior view of s.ame; (3) lateralview of opposite spine, a, Anterior border; p,posterior border.

Fig. 66.— Anteeior paik

the basal portion of the spines, whereas in allother described forms, where the spines are
known, the bases of the anterior pair greatly
exceed those of the posterior pair. This feature reaches its maximum development
in S. sulcatus.

The base of the spine shown in figure 66 has an antero-posterior diameter of
145 mm. and a transverse diameter of 110 mm. Like measurements of the otherthree do not vary 5 mm. in either of these dimensions.

112

UNITED STATES NATIONAL MUSEUM.

These spines have the usual oblique ends, so that in life they would be directed
outward and backward at a consideAble angle from the perpendicular (see fig. 65).
The lower ends of the anterior pair are rugosely roughened with weakly developed,H

asymmetrically placed
longitudinal keels the;posterior pairis smooth

and without keel.

The spines are unusually flat and slenderwith sharp edges fore
and aft throughout
entiretheirlength.

The lower part of the
shaft

is

slightly con-stricted

antero-poste-

that
the
widest portion of theblade is some 200 or
250 mm. above thebasalend. Inallotherspecies the spines gradually taper from thebase to the very tips
riorlyso(see fig. 60).

The

long,

flattened

slender,

shaftswithsharp edges; the constriction of the shaft
above the bases; andthe uniformity in thedevelopment of thebases of the spine series
are a combination ofcharacters which willatonce separate thetail spines of S. longi-

spinus from other describedprincipal

species.

The

featuresofthese spines are wellshown in figure 66.
Turning now to the caudal vertebrae we find that the anterior members of theseries have the usual short centra and robust spines with expanded summits;
the median caudals are more elongated with hexagonal centra, and appear indistinguishable from those of the type of S. stenops.

.

OSTEOLOGY OF THE AEMOEED DINOSAUBIA.

113

Coming to the caudals of the distal portion of the tail, of which there are 10
present, these show such distinctive differences from those of the other species,(fig. 67) that the question of their proper association with this specimen was atonce raised. In reply to my inquiry, Mr. Eeed assures me that there can be noquestion but that they belong to the type-specimen, as this skeleton was foundisolated, that is, there were no bones of other animals found in the same quarry
with it.

The characters by which these vertebrae differ from those of the other speciesof Stegosaurus are contrasted in the two parallel colunms below.
S. longispinus

Other species.

Centra depressed.
Centra rounded when viewed from end.
Sides of centra deeply concave.

Centra compressed laterally.
Centra hexagonal when viewed from end.

Vestigal transverse process.

Process wanting.

Centra mushroom headed.

Heads of centra without special expansion

Sides of centra moderately concave.

The spinous processes are missing from all of the distal
Measurements taken of the centra show the transcaiidals.
verse diameter to always

exceed the vertical, whereas in

the distal caudals of other species the vertical always equals
if it does not exceed the transverse diameter.

Although

there

are

considerable portions of

the sa-crum present it is too fragmentary to be compared to advantage.

Such dorsal vertebrae as are preserved show the usual
elongated neural processes, with upwardly directed diapophyses, and small laterally compressed centra.
These show no
distinctive features.

The cast of the sacral cavity is depressed and considerably more expanded laterally than in S. ungulatus. How
much of this flattening may be attributed to crushing it is
impossible to say.

The ischia are of the same size as those of S. stenops, anddiffer only in minor details (pi. 25, fig. 4).

The femur in its general proportions closely resembles
those of the type-specimen of S. stenops (fig. 45), as in thatspecies thefemur

may be distinguished from those ofS.

ungulatus by the presence of the finger-like lesser trochanteron the external anterior face of the proximal end (a, fig. 68).

The condyles are illy defined, being wide apart, with articularFig. 68.— Right

femuk of

Stegosaurus longispinus.
Type no. D 54, UNrvEKSiTY

OF Wyoming, ^nat. size.
surfaces confined almost exclusively to the distal view.
It
Front view, a, Lesser
trochanter; b, gf.eater
has a greatest length of 1,082 mm.; other measurements aretrochanter;head.
given in table on page 83.
The few ribs present show the usual T-shaped cross-section of the" proximalft,

portion.

—:

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

114

Family SCELIDOSAIIRIDAE Huxley.

Genus

HOPLITOSAURUS Lucas 1902.
HOPLITOSAURUS MAESHI (Lucas) 1901.
Plates 26-30.

Stegosaurus marshi Lucas, Proc. U. S. Nat. Mus., vol. 23, 1901, pp. 591, 592, pk. 23-24.

HoplitosaunLs marshi (hvcAs) Science, new ser., vol. 16, No. 402, 1902, p. 435. Lull, Amer. Jouin.
Sci., vol. 29, 1910, p. 30, fig. 7.— Zittel, K. A. Grundzuge der Palaentologie, pt. 2, 1911, p. 294.

—

Consists of the right femur, proximal
Cat. No. 4752 U.S.N.M.
humerus; distal half of right humerus. Proximal portion of rightscapula and coracoid, one dorsal centrum, caudal centra, numerous dermal platesof the spined, keeled, flattened, and rounded shapes; fragments of ribs and otherelements. Collected by N. H. Darton in 1898.
"Calico Canyon," near Bufl'alo Gap Station, South Dakota.
Type-locality.

Type-specimen.

half of left

Horizon.

——I^akota, Lower Cretaceous.

In 1901 Lucas first described this specimen as a new species of Stegosaurus.
but a year later, recognizing its affinities as being nearer the Wealden Polacanthus,
and therefore distinct from the former genus, he proposed the name Hoplitosaurus
Since 1901 four genera and as many species of armored dinosaurs
for its reception.
have been described from the Cretaceous of this country; but in none of these articles is there reference made to the present form.
It would appear on account of
the closeness of the geological horizons in which some of these specimens were
found that, when a comparative study is made, they will be found to be closely
allied, if not identical, with the present genus.
The famih^ attribution of Hoplitosaurus in aU probability lies within the
Scelidosauridae of Huxley, an assignment which I beUeve will eventually include
other genera of American ridge-scuted dinosaurs.

The original description by Lucas follows
The same Stegosaurus marshi is proposed for a new species of Stegosaur represented by a numberof plates, spines, and portions of the nuchal and gular armature, as well as by some vertebrae and bonesof the limbs, obtained by Mr. N. H. Darton in South Dakota from beds considered by him to be ofLower Cretaceous age.
This material, which is in the United States National Museum and is the type of the species, isnumbered 4752 in th6 catalogue of fossil vertebrates. It was found associated with remains of anotherdinosaur of moderate size, probably related to Camptosaurus.' The species is characterized by thegeneral massive appearance of the plates and spines, the comparatively large extent of their basal surfaces, their abrupt taper, and sharp edges.
In these respects they are quite different from the corresponding portions of any other Stegosaur yet discovered, and coming, as they do, from the highest
horizon in which remains of Stegosaurs have been found they may be considered as representing thelatest developments in the dermal armature of this remarkable group of dinosaurs.

A dermal spine found by Mr. J. B. Hatcher, in conjunction with remains of Triceratops, andregarded at the time as belonging to that genus, may very likely have come from the species underconsideration.

A spine, shown on plate [28], presumably from near tlie posterior end of the caudal series, has a longand comparatively wide basal portion and then tapers rapidly to a spike-like form.
A plate, shown on plate [29], apparently from the caudal series somewhat in advance of the spine
just described, is triangular in section, slightly rounded on one surface, while on the other it tapers
abruptly from the base with a concave curve.
1Type-specimen of Camptosaurus depressus Gilmore— C. W. Gilmore.

OSTEOLOGY OF THE AEMOBED DINOSAUBIA.

115

Another plate, probably from tlie dorsal series, is much more compressed than either of the two
already noted, and seen in profile has the form of a rather narrow high triangle.

None of the large flattened plates so characteristic of Stegosanrs hitherto described are present,
and while the material available is too scanty to warrant any positive assertion regarding them, yet it
seems probable tliat in the species under consideration all the plates were small and heavy.
The nuchal armor consists of small, thick, irregularly quadrilateral plates slightly keeled, andthese, save for their smoothness, are suggestive of the nuchal and dorsal plates of crocodiles.

The throat was protected by rounded ossicles varying from 3 to 25 mm. in diameter, and many ofthese are present on the slab containing the nuchal plates.

It is entirely probable that this species
represents a distinct genus of Stegosanrs; but in tlie absence of material on which to base a genericdiagnosis it seems best not to bestow upon it a new generic name.

This specimen was recognized by the late Prof. O. C. Marsh as representing a new form, and as it
was almost the last specimen to be studied by him it seems particularly appropriate to name the species
in honor of one who did so much to make the Stegosaurs known.
The following are tlie measurements of the spine and plates described: Caudal spine, shown onplate 20, 370 mm. high and 252 in antero-posterior diameter; caudal plate, shown on plate 21, 304 mm.
high and 155 in antero-posterior diameter; width of articular face 148 mm.; dorsal plate 380 mm. ingreatest height, and 198 in antero-posterior diameter.

—

Scapula and coracoid. The scapula as in Ankylosaurus is especially thick andThickest above the humeral articulation and narrowest just posterior
to that point, where it measures 108 mm. across the shaft.
The upper portion of the blade is missing, but from the proximal portion it
would appear to have been decidedly concave from end to end on the inner surface.
A heavy oblique ridge rises from the median external surface of the shaft
just posterior to the glenoid cavity and continues forward and upward, terminating
at the acrominal border. The forward termination of this ridge overhangs thelower external surface of the bone. It appears very similar to the outwardly
curved superior borders of this portion of the Anlcylosaurus scapula as describedby Brown,' and resembles somewhat the process fotmd on the scapula of Hylaemassive.

osaurus.^The coracoid is firmly coossified with the scapula and with it forms a shallow
but extensive glenoid cavity. The coracoid foramen passes almost straight thi-oughthe bone, not diagonally as in Stegosaurus and Ankylosaurus. The coracoid is aflattened discoid bone, its general proportions being wellshown ia plate 26, figure 3.

At the articulation with the scapula it has a vertical measurement of 190 mm.
Humerus. The humerus of Iloplitosaurus Is represented by the distal half of—the right and the proximal portion of the left (pi. 26, figs. 1 and 2).

it to have been a short bone, with widely expanded ends, that aremuch flattened ante-

These pieces show

The deltoid ridge, although broken, appears to have been well developed, and as in Stegosaurus extended well down on the side of the shaft. The
radial and ulnar condyles are feebly developed, being separated by a very shallow

roposteriorly.

trochlear depression.

The supinator ridge is much more prominent than in Stegosaurus, and its greatmuch to the width of the distal end of the bone.
On the posterior side the olecranon fossa of the mammahan humerus is represented
transverse development adds

by a broad and very shaUow depression. The head is less robust than in Stegosaurus
and does not overhang to any appreciable extent the posterior surface of the shaft.
•

Bull. Amer. Mus. Nat. History, vol. 21, 190S, p. 196.

'

Owen, Wealden, and Purbeck Reptilia, Mon. Pal. Soc, 1858, pt. 3, pi. 4.

UNITED STATES NATIONAL MUSEUM.

116

From these two parts of opposite humeri it is estimated the total length of
the humerus in this individual would be about 385 mm. The greatest transverse
measurement of the distal end is 165 mm.
In the considerable expansion of the ends and the contraction at the center
the humerus in Hoflitosaurus resembles those of Polacanthus and Acanthofholis.
Femur. The right femur is almost perfectly preserved, lacking only a portion
It was found in the matrix of the lower side of the blockof the fourth trochanter.
containing the dermal ossifications shown in plate 27. Although only Httle morethan one-half the length of the shortest Stegosaurus femur in the National
Museum collections, the proportions of these bones are remarkably similar. The—

femue op Hoplitosaueus maeshi (Lucas). Type. Cat. no. 4752, U.S.N.M. j nat. size. (1) Feont
Back VIEW. (3) Exteenal view, ct. Lessee tbochantee; 6, qeeateeteochantee; ft, head; i.e., inteenal

Fig. 69.—Eight

VIEW.

(2)

CONBTLE;0.

C, OUTEE CONDYLE; i, FOUETH TEOCHANTEE.

articular parts of the proximaland distal ends are in general aspect typically

The head is not as distinctly separated from the rest of the proximal end as in Polacanthus, but resembles more nearly the conditions found in
Stegosaurian.

rugose proximal surface continues uninterruptedly over theend to the external border. The lesser trochanter (a, fig. 69) isrelatively more strongly developed in Hoflitosaurus than in Stegosaurus.
It ischaracterized by its compression in the direction of the bone it is roughened externally and divided by a narrow fissure from the neck of the femur. The flattened
nature of this trochanter and its external position, on the proximo-anterior face,would at once serve to distinguish it from other femora pertaining to the armored
Stegosaurus; theentire proximal;

dinosauria.

117

OSTEOLOGY OF THE ARMOEED DINOSAUKIA.

The

external border continuing

down fromthe proximal end

isrugoselyroughened, and with the process here called the great trochanter was probably the
point of insertion of the gluteal muscles. It appears that with the retrogressionof this trochanter, which is vestigal in Stegosaurus, the point of insertation of thesemuscles gradually changed, until, in S. ungulatus and in the Sauropod dinosaurs,
with the disappearances of this trochanter, the superior outer border functions as
the trochanter major, as first correctly determined by Osborn in Diplodocus.
The shaft is shghtly bowed from end to end, the arcuation of the center being
forward. The bone is flattened antero-posteriorly being wider than deep.
The fourth trochanter is present, and placed above the middle on the posterointernal border of the shaft, and although broken as mentioned above, appears tohave been more prominently developed than in Stegosaurus.

The external condyle (see oc, fig. 69) as in other dinosaurs is larger than theup well on the back. They are separated by a wide but
shallow intercondylar notch. The internal condyle is weak and much compressed
inner, both roundingtransversely,

and has on its internal side the usual longitudinal groove.
Measurements of Femur No. 47S2.

Greatest length495Greatest breadth proximal end

190Greatest breadth distal end

170

Least width of shaft

65

Dorsal vertebrae.

—The dorsal region of the backbone

is represented

by a soMtary

dorsal centrum, which is considerably distorted by pressure. Making due allowancefor distortion, the centrum would be deeper than wide, with flattened sides andshghtly expanded ends, having concave articular stufaces. Nem-al canal large;
pedicels of neural arch contracted antero-posteriorly as they rise from the centrum,suggestive of a high neural process. The principal measurements of this centrum
are: Greatest length 74 mm.; greatest height 63 mm.; greatest transverse diameter 50 mm.

Caudal vertebrae.

—Six caudal vertebrae were found withthis specimen, but thegreat size of three of these precludes the possibility of theh pertaining to this indiThis also renders the association of the remaining three somewhat probvidual.
lematical.

The better preserved one from the median caudal region has a massive centrum
being as wide as long; articular ends slightly biconcave; chevron facets weU developed on posterior end; diapophyses leave the centrum on a level with the neural
canal, the latter comparatively small, with greatest diameter transverse; spinous
process missing, though the fractured base mdicates that it was thickened.
This centrum has the following dimensions Greatest length 80 mm. greatest
width 80 mm.; greatest height 65 mm. A caudal from the distal end of the tail:;more elongated; without transverse process; centrum somewhat compressed transversely; with biconcave ends. It has a length of 50 mm.
The ribs, with the exception of the proximal portion shown in plateEihs.
is relatively—

Many of these fragments are triangular m cross section.
From these pieces it would be inferred that none of the ribs were very massive.
27, are all fragmentary.

51873°— Bull. 89—14

9

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

118—

As in Polacanthus, Hylseosaurus, AcanihopJiolis, Nodosaurus,
Ankylosaurus, and Hierosaurus, the dermal arnaor of Hoplitosaurus

Dermal armor.
Stegopelta,

complex character, combining as it does scutes of at least five different(1) simple flattened;(2) romided ossicle-like; (3) keeled; (4) triangularplate-like, and (5) spined.
(1) Those of the first kind are thin, rectangular scutes with rounded corners
and without surface sculpture or ornamentation. Two of these, shown in plate 27,
have the surface gently concave across the shortest diameter.
They(2) The ossicle-like scutes are the most numerous of those preserved.
vary greatly in size and shape, being rounded, oblong, elHptical, and subrectangularforms, that measure from 10 mna. to 50 mna. in the longest diameter. The blockof sandstone shown in plate 27 is thickly studded with them, in some instances
three and four being found one above another.
These are undoubtedly the scutes to which Lucas refers as representing thegular armature, a decision reached, no doubt, on account of the resemblance of
is

of a

forms;

many of the scutes to ossicles forming the throat investiture of Stegosaurus.

Since
the femur was found attached to the lower side of this block of sandstone, there
is reason for thinking that these ossicles in conjunction with other dermal structures may have formed a carapace-like covering over the pelvic region, as is known
to be the case in Polacanthus

and Stegopelta}

There are numerous keeled scutes preserved, and they also vary much insize and shape.
Some are buttonhke, being raised in the center as a blimt conelike projection {d and d' fig. 70), but the greater number are elongated, angularly rounded, with a sharp keel on the dorsal surface, asymetrically placed.
In
all of the examples before me this ridge is highest in the center, gradually sloping
toward both ends. None show a projecting spur such as found by Wieland ^ insimilar scutes of Hierosaurus.
One of the better preserved measured throughthe center has a thickness of 32 mm. One or more scutes are almost flat, with an
obtuse ridge (c and c', fig. 70), very similar to those found with the remains of(3),

AcanthopTiolis, as described by Huxley.''

The ventral side of some of these scuteshow the same texture of coarsely woven cloth, as described by Marsh in
Nodosaurus, and the dorsal surfaces of a few are scrobiculate as in Stegopelta.*(4) The large subtriangular, plate-like structures, closely resemble those of
Polacanthus, which Nopcsa ^ upon the evidence of associated material assigned
to the caudal region in two rows along the top of the tail (fig. 72)
Doubtless fromplates.

their close resemblance they will eventually be found to occupy a similar position

The base is hollowed out as in the tail plates of Scelidosaurusand Hylseosaurus, and as in the case in many of the dermal plates of Stegosaurus.
A well-preserved example of this style gives the following measurements:

in Hoplitosaurus.

Greatest diameter antero-posterior, 210 mm.; greatest vertical diameter, 175 mm.;greatest transverse diameter, 65 mm. As in nearly all the larger plates the lateralsurfaces are covered with blood-vessel impressions.
W. WiUiston, Science (n. s.), vol. 22, 1906, p. 504.

1

S.

3

Amer. Joum. Sci., vol. 27, 1909, p. 252.

3 Geol.

Mag., vol. 4, 1S67, p. 65, pi. 5, flg. 1.

*

R. L. Moodie, Science Bull., vol. 13, 1911, p. 267.

=

Geol. Mag., vol. 2, 1905, pp. 246-249, flg. 6, pi. 12.

OSTEOLOGY OF THE ABMOEBD DINOSATJRIA.

119

Of the spined scutes there are portions of eight present, five of which are
The form of all when viewed laterally may be roughly described
as triangular, and nearly all are elongated and asymetrical.
For convenience of(5)nearly perfect.

description these may be subdivided into the following:(a.) Scutes with median, transversely expanded, obhque bases;
above base""greatly expanded antero-posteriorly, contracting rapidly to a rounded spine whichrises from near the center of the plate, tapering to blunt upper extremity.
What

I take to be the external side is angularly convex antero-posteriorly, the innerFig. 70.— Dermal scutes of Hoputosaueus maeshi (Lucas).

Type. Cat. no. 4752, U.S.N.M. J nat. size, o, Eidged
scute; a', cross-section of same; 6, triangut.ae scute; 6', cross-section of same; c, circular ridged scute; c' crosssection OP same; d, circular noded scute; d', cross-section or same; n, node-like elevation.

The anterior and postei'ior edges of the lower third of the plate
present sharp bordere, becoming more obtuse as they pass into the spine. Correcting the measurements given by Lucas of the spine shown in plate 28, thegreatest length is over 390 mm.
and the greatest length antero-posteriorly is 280
side being less so.

;

Nopcsa is correct in the placing of the dermal armor in the restorationof the English Polacanthus, these spines would pertain to the anterior half of theanimal, as shown by the close resemblance of the present spines as compared withthose of that genus.
(Compare pi. 28 with fig. 72.) Lucas in his description
considered them as belonging to the distal caudal region. A modification of this
mm..

If

—

;

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

120

type is shown in figure 71.

There is not the sudden development of a rounded
The edges fore and aft, from top tobottom, are sharp and the tiiangular spine is compressed transversely. Alongthe inner side of the base of both tliis and the preceding spme there is a longiGreatest height of this spme
tudinal depression as if for its insertion in the sMn.
is 290 nmi.; greatest length antero-posteiiorly, 190 mm.; greatest width of baseabout 55 mm.
(&) Dermal elements with compi'eased grooved bases and spine; longitudinallygrooved on posterior bordere. Throughout the entire length of the bone, a crosssection would be triangular in outIme, with the base resting on a levelsurface, the spine continuing upward,
outward, and backward, overhanging
the posterior border of the base (pl. 29,

spine as shown in the scute described above.

1 aud 2).
The anterior or convex edge is sharp throughout its entire
length. The body of the bone is moderately convex longitudinally on one
side and correspondingly concave on
the opposite side. In its generalform it resembles most nearly dermal
elements fomid with the skeleton ofHylsRosaurus} The prmcipal features

figs.

of

plate are well shown in plate
The greatest height is 330 mm.

tliis

29.

greatest

Fig. 71.

Type.

Dermal plate of Hoplttosadrus makshi (LncAS).
No. 4752, U.S.N.M. } NAT. size. 1, Lateral tiew; 2,

END YIZV,' OF SAME.

lengthantero-posteriorly,

about 210 mm.
(c) These have heavy, massive,
expanded bases, spines compressedwith edges, sharp both fore and aft;base

somewhat

obliquely

beveled,spine curved outward ; greatest height

more than 270 mm.; greatest length antero-posteriorly, 175 mm.; greatest width of
A modification of tliis type is sho^vn in plate 30, figures 1 and 2. The
spinous part is reduced to a mere sharp ridge of bone rising from a massive base.
It has the proportions of those placed by Nopcsa just in front of the pelvic shield inbase, 150 mm.

Greatest height, 122 mm.; greatest length antero-posteriorly,
140 mm.; greatest width of base, 100 mm.

Polacanthti^ (fig. 72).

As may be readily seen from an inspection of the figures, these skin ossifications
in JIoplitosaunk<i present far more variety of form than do those obtained with theremains of any American dinosaur Icnown at the present time.

They vary all the way from small, rounded tubercles to plates of good size, andfrom simple flattened scutes to those with sharp ridgings and sjjines.
'

See d.d.d. pl. 4. Fossil Reptilia of the Wealden and Purbeck, 1858, p. 25.

'

OSTEOLOGY OP THE AKMOEED DINOSAUKIA.

121

As to the position of these various shaped skin scutes, the present specimen
and anything that can be said regarding them is largely
a matter of conjecture, since all were mixed up in somewhat of a disassociatedmanner and mingled with various other parts of the skeleton.
Judging from the length of the femur the present dinosaur in life was of low
offers but few suggestions^stature, with a height at thehips of about 4 feet, and thatitwas quadrupedal in gait

appears to be indicated by
the robust character of suchparts of the pectoral girdle

and fore limbs as have beenpreserved.

DiNosAuu Armor prom theLance Formation.

In 1911 Wieland figured
and described a number ofdinosaurian dermal plates
from the Lance formation of

Wyoming that are now preserved in the paleontologicalcollections of Yale University.
While none of these were so
associated with other bones
as to be positively identified,they are of interest as showing agreat diversity of shapes,
and they especially emphasize
the paucity of our knowledge
concerning the animals towhich they belong. Complying with Wieland's suggestionthat "it would be of very
considerable interest to know
the actual number and pro-portion of these elements inthe collections, and especiallytheirassociations,"

I

have

prepared a brief account of
those in the United States
National Museum, with figures of the more characteristic plates.
Cat. No. 5793 is the dermal element (fig. 73) figured by Marsh ^ as the dermal
spine of Triceratops and of which Hatcher ^ says "may have been arranged in pairs'

23Amer. Joum. Sci., vol. 31, pp. 119-122, flgs. 4-7.
Dinosaurs of North America, 1S96, pi. 70, figs. 1-3.
The Ceratopsia, Mon. 49, U. S. Geol. Survey, 1907, p. 65, figs. 74 1-3.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

122

at the base of the tail [Triceratops]."

In general it bears a striking resemblance

to the dermal spine of Hoplitosaurus marsJii shown in plate 30, and on the analogyof the dermal armor of Polacanihus (fig. 72), to which Hoplitosaurus appears to
be closely allied, I would say that spines of the character of these would belong
to the armor in front of the sacrum over the middorsal region rather than to thecaudal series, the position assigned it by Hatcher.
From available records I am unable to say anything of its association withother bones in the field. Collected by J. B. Hatcher in Converse County, Wyoming.
Cat. No. 724.3, a thickened subrhombic plate with heavy obtuse median ridge,
No other bones
lower surface concave across the shortest diameter (pi. 31, fig. 3).
or fragments associated. Collected by G. L. Wait at Dovetail Butte, about 1 mile
west from ranch of E. J. Sanford, Valentine, Fergus County, Montana.
Cat. No. 7724, a single heavy curved plate resembling somewhat Wieland'a
It was associated with fragments of dinosaur bones, but
figure 4 (pi. 31, fig. 4).
none were sufficiently complete to be identified. Collected by A. L. Beekley in

Carbon County (SE. \ sec. 14,
T. 24 N., R. 84 W.), Wyommg.
From the Lance formation.
Cat. No. 7726. Some half
dozen rounded and ellipticalplates with spinal node andFig. 73.—Dermal spine of a Ceeatopsian? dinosaur. Cat. No. 5793,
XT.S.N.M. About ^V nat size, a, Side view; 6, front view; c, top

view,

&

^"

'

J

&•

h

which undoubtedly pertain tO

after Marsh.

^^g ^^^^ species as those figured by Wieland in figure 5 of the article cited above. These were collectedby D. F. Hewett near Cody (NE. \ sec. 23, T. 50 N., R. 100 W.), Big Horn County,

Wyoming.
Nos. 7804-7805. Two pointed spine-hke ossifications {A and 5, fig. 1, pi. 31).
by J. B. Hatcher in Converse County, Wyoming. From the Lance
formation.

Collected

RESTORATIONS OP STEGOSAURUS.
Since Prof. O. C. Marsh published the first pictorial restoration of Stegosaurus
ungulatus, in 1891,' there have appeared, from time to time, various pictures andstatuettes depicting the life appearance of this curious reptile.
These show a considerable variety of interpretations and are of iuterest as

exhibiting the diverse opinions held regarding its probable appearance in the flesh
and especially as to the arrangement of the dermal armor. In plates 32 to 36 andarranged in chronological order are some of the more striking of these restorations.
Some comments upon the more important structural differences displayed in these
restorations are given below.

As mentioned above, Marsh made the first restoration of Stegosaurus shown here
It was based upon the cotypes ^ of S. ungulatus (Nos. 1853
and 1858, Yale Museum), "while some other parts, especially of the dermal armor,

in plate 32, upper figiure.

have been placed in accordance with the known position in Stegosaurus stenops " (No.
It ynH be observed that notwithstanding the positive evidence
4934, U.S.N.M.).
1

Amer. Joum. Sci.. vol. 42, 1891, pi. 9.

»

R. S. Lull, Amer. Joura. Sci., ser. 4, vol. 30, 1910, pp. 363-364.

OSTEOLOGY OF THE AKMOKED 0INOSAUKIA.

123

furnished hj the S. stenops skeleton as to the existence of two parallel rows of 14
dermal plates, Marsh placed the series ia a single row of 12 along the median lineof the neck, back, and tail, with four pair of spines near the end of the tail.

In 1893 ' the Rev. H. N. Hutchinson pubHshed the first life restoration by
T. Smit, shown in plate 32, lower figure. It was evidently based upon Marsh's restoration, as indicated by the position, shape, and arrangement of the armor, althoughby the artist to slender pin-like affairs, occupying a
The pose was changed from an upright quadrupedal gaitto that of a bent-limbed, crawHng reptile of the crocodile type.
This attitude is
opposed to all of the generally accepted ideas of the normal mode of locomotion
the tail spines were reduced

nearly vertical position.

of this animal.

The restoration shown in plate 33, upper figure, pubUshed for the first time, wasdrawn by Mr. Frank Bond, in 1899, under the direction of the late Prof. W. C. Knightof the University of Wyo m n g.
It is of interest as showing the plates arranged in
procumbent positions, a view not alone held by Knight. AE of the evidence, however, is opposed to such an arrangement of the armor.
In 1901^ Lucas pubHshed the next restoration (pi. 33, lower figure), a paiating
by Mr. Charles R. Knight. This was the first to show the plates arranged in pairs.
In the same year a second restoration (pi. 34, upper figure) was made by Mr. G. E.
Roberts, under the direction of Mr. Lucas, and the first showing the alternation of
the plates of opposite rows, and the reduction of the tad spines from four to two
pairs.
The proportions here shown are extremely bad, the body being too long, andthe limbs especially crude in form and pose. The only use made of this restoration,so far as I am able to learn, was in a popular magazine article bj^ Mr. R. I. Geare.^
In 1903 a statuette (pi. 34, lower figure) was prepared by Knight under the
direction of Lucas, in which the arrangement of the armor is practically the same as in
the previous restoration by Roberts, although the inaccurate proportions of the bodyand limbs were corrected. From this small model a life-size restoration was madeand formed a part of the exhibit at the World's Fair held in St. Louis in 1904. It
is now displayed in the hall of fossil vertebrates in the United States National
Museum. Although according to our present knowledge it is now known to beinaccurate in several details, yet, taken all in aU, it probably comes nearer thetruth than any representation yet produced.
In 1905 Lankester^ published the restoration of Stegosauras shown in plate 35,
lower figure, and was the first to depict the animal with a color pattern of irregularlyrounded black spots upon a lighter body color. The hooked raptorial bird-like beak,the puffed-up proportions of the body, and the increased number (10) of dermal spines
are without warrant. In fact, there is but little to commend in it. It may be ofinterest to know, however, that Sir Arthur Conan Doyle used this restoration as
an illustration in his story of The Lost World.
A second restoration by Smit is shown in plate 35, upper figure. In thisrepresentation there was a return to the upright quadrupedal pose (compare pis. 32,
i

''

1

Extinct Monsters, 1S93, 2d ed., pi. 10.

2
3

Animals of the Past, 1901, fig. 24, Smithsonian Report, 1901, pi. 4.
Outdoor Life, July, 1910, p. 6.

'

Extmct Animals, 1905, p. 208, fig. 150.

s

H. N. Hutchinson, from a revised edition, 1911, of Extinct Monsters and Creatures of Other Days, pi. 26.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

124

lower figure, and 35, upper figure) and a general rearrangement of the plates ofthe dermal armor. The alternation of the plates of opposite rows is shown, but
the median part of the tail was bereft of its dermal adornment., The reason forthe latter change is difficult to conjecture unless it were reasoned that it allowed
greater freedom of movement and thus facihtated the use of the tail as an offensive instrument so that the dermal spines near the tip could be brought into action.

At best it is more fantastic than in accord with the known facts.
The latest concei>tion (pi. 36, lower figure), as exemplified by a recently mounted
skeleton ^ in the Peabodj^ Museum of Yale University, erected under the directionof Prof. K.. S. IjuU,

and after which he has prepared a small model- (pi. 36, upper

figure) of the animal as he appeared in the flesh, shows a return to the paired arrange-

ment of the plates and the retention of four pairs of spines on the tail.
Since the mounted skeleton and life restoration by IjuII embody all of the latest
ideas (up to the year 1912) regarding the articulation of the bones of the skeleton

and the life appearance of Stegosawus, it only becomes necessary for me to pointout wherein they difl^er from the facts revealed during this more recent study of alarge series of Stegosaurian remains.
I appreciate only too well the difficulties
encountered in mounting for the first time the skeleton of one of these huge andgrotesque creatures, and in justice to Professor Lull I would say that he now recognizes the correctness of some of the observations recorded below.
It is in the dermal armor that the greatest alterations are now to be made,and since the evidence for these changes is discussed in detail in the descriptive
part of this paper, it is only necessary to enumerate them here.
1. The plates of opposite rows alternate, not paired as shown in the restoration.
2. There are not more than 22, and perhaps only 20, in the complete series offlat plates, whereas the restored skeleton shows 28.
It is quite possible, however,that the number of these plates may vary, within limits, with the individual.
3. The largest plate of the series, as shown by the two individuals found in
situ, is above the base of the tail, not over the sacrum.
4. Dermal spines number four, based on the evidence of association in six
individuals.
5.

Number of overhanging spine-like caudal plates to be reduced from six totwo, on the evidence of two individuals.
6.

First plate of the series above the atlas, not over the fourth cervical, as

shown in the mounted skeleton.

It is of interest to note that Owen figures the firstpair of dermal elements in Scelidosaurus (as found in the matrix) immediately

above the atlas.
7. Bases of the plates of opposite rows throughout the series, comparatively
close together on either side of the middle line of the back.
Not supported by the
upwardly directed transverse processes of the dorsals.
8. Although the evidence is not conclusive, there is every probability that thesmall rounded, so-called gular ossicles covered the top and sides of the head andneck, rather than the throat, as represented in restorations (pi. 32, upper figure).
1

Amer. Journ. Sci., vol. 30, 1910, flgs. 2, 3, and 4.

=

Idem, pi. 2, and flg. 10.

—

OSTEOLOGy OF THE ABMOEED DINOSAURIA.

125

A study of the crania in the National Museiim shows that in all the occipital
condyle is deflected downward in such a way from the longer axis of the skull as
to cause the anterior portion of the' cranium to be carried low in front if the condyle is to be in line with the cervicals. While the articulation is such as to allowof further depression and also of elevation, it would seem that the normal pose
would be much as in Camptosaurus, Trachodon, Triceratops, and Diplodocus. Allof the pictorial restorations shown in the preceding pages, with the exception of
Knight's (pi. 33, lower figure), show the head with an extreme elevation of the nose.

In the fore feet, as shown by the articulated limb of S. stenops (fig. 40), there
but a single row of ossified carpals, and it appears from the evidence of otherfeet that the third, fourth, and fifth digits carried a reduced number of phalanges
not a full complement as shown in the Yale skeleton.
As LuU* has pointed out, "The feet are large as though to support the creature's
weight on yielding soil, the hand evidently possessing five, while the foot bore
three, well-developed digits (and one which is vestigal).
The semi-digitigi'ade
feet were doubtless inclosed in a fleshy mass as in the modern elephants, while
the external indications of the digits were mainly the hooflike nails."
It seems
most probable that in life only two of these digits (I and II) were in evidence.
The body is lank, but I can not agree with Lull that the hips are narrow, forwhile they do not have the great breadth of the Triceratops pelvis, they are nevertheless of good width.
I would question somewhat the proportions of the skeleton shown in plate 36,
lower figure, as being typical of the Stegosaurian dinosaurs. The great elevation of
the trunk and tail above the ground is evidently brought about by the unusual
length of the femora used in this composite mount. The stilted appearance of
this specimen, I am sure, would not be attained by any of the individuals in the
National Museum collections. The difference in length between the exceedingly
long femora used in the S. ungulatus skeleton and the longest ones before me isiswell shown in figure 45.

The gi'eat height of the hips brought about a corresponding elevation of theshoulder region which in this specimen necessitated the straightening of the forelimbs almost to their limits in order to articulate them with the skeleton. This
does not seem to me to be the normal standing pose, for the presence on the ulnaof a large olecranon process and the development of strong rugose processes on
the humerus are features implying a bent, strongly flexed limb of the Ceratopsiantype.

With, shorter femora such a pose could be easily brought about in themounted skeleton with the resulting advantage of bringing the head nearer the
ground, obviously a more natural position, for in the present pose, on account of
the short neck, the animal's nose could only have reached the ground with thegreatest difficulty.

The mounting of this skeleton shows the animal as being somewhat shorter
than Marsh's estimated length of 25 feet. Lull gives the total length of this specimen between perpendiculars as 19 feet 5 inches and the greatest height from thebase to the top of the highest plate as 11 feet 10^ inches.
J

Amer. Joum. Sci., ser. 4, vol. 30, 1910, p. 367.

The latter measurement

126

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

will be somewhat less when the plates are properly placed.

The average Stegosaurus

would probably measure somewhat less in length, for this skeleton is based upon
The present weight of the fossil
the remains of old and very large individuals.
bones is 1,917 pounds, and Lull has estimated the live weight of the animal as being
between 7 and 10 tons.
As in nearly all dinosaurs the articulai' surfaces of the limb bones give but
httle positive evidence as to their exact manner of articulation, and any statement
as to their normal pose largely resolves itself into a matter of personal opinion.
I had hoped to present at this time an illustration of a mounted skeleton of
Stegosaurus stenops that it is proposed to erect in the United States National Museum, and which would graphically portray the ideas set forth here as to the ai-

Work of a more urgent nature, however,ticulation of the bones of the skeleton.
has delayed the mounting of this skeleton and it has been deemed inadvisable
to longer postpone the present paper pending its completion.
The skin covering of Stegosaurus is at this time wholly conjectural, although
in the Hght of recent discoveries we may yet hope to have definite knowledge as
Lambe^ has recently described impressions of the dermal covering
to its character.
of a Ceratopsian as consisting of " nonimbricating plate-like and tubercle-like scales."Based upon this evidence and from what is known of the integument of the Trachodont dJnosaure it is reasonable to expect the covering of Stegosaurus to be scalelike, with numerous bony skin ossicles scattered over the entire body, instead of
the smooth leathery elephant-like texture which has so often been represented.
The exceedingly small and feeble teeth would appear to indicate that Stegosaurus must have fed upon the most succulent of terrestrial plants. The structureof the feet suggests that they were land haunting, doubtless of low swampy regions
rather than the upland, but they suggest the probability of being adaptations froma group higlily specialized for locomotion upon land. There is every reason to
beUeve that Stegosaurus was descended from a bipedal ancestry as first suggested
by Dollo. Increasing bulk and development of the armor caused them to losecelerity of movement, and they became sluggish, slow-moving creatures of low
mentality, only sufficient, perhaps, to direct the mere mechanical functions of life
1

The Ottawa Naturalist, vol. 27, 1914, pp. 129-135.

LIST OF WORKS CITED.
Bebchek, C. E.

The Reconstruction of a Cretaceous Dinosaur, Claosaurua annectens Marsh.

Trans.

Conn. Acad. Sci., vol. II, 1902, pp. 311-324, pis. 41-45.

New Notes on the Osteology of Triceratops.

Beown, Baenum.

Bull. Amer. Mus. Nat. Hist., vol. 22,

1906, pp. 297-300, pi. II, text figs. I, 2.

The Ankylosauridae, a New Family of Armored Dinosaurs from the Upper Cretaceous.
Amer. Mus. Nat. Hist., vol. 24, 1908, pp. 187-201, figs. 1-20.
.

A new Genus of Dinosauria from Colorado.

Cope, E. D.

Bull.

Amer. Naturalist, vol. 12, 1878, pp. 188, 189.

(Brief notice of discovery of Uypsiro-phUH.)

New Jurassic Dinosauria. Amer. Naturalist, vol. 13, 1879, pp. 402^04, with three wood cuts,(Type description of Hypsirophus seeleyanus.).

Gaupp, E.

Beitrage zur Konntnis des Unterkiefers der Wirbelthiere.

Anat. Anz., vol. 39, 1911, pp.

97-135, text figs. 1-16.

Geaee, R. I.

Some Extinct Animals.

GiLMOEE, C. W.
tosauruB.
.

Outdoor Life, vol. 26, No. 1, 1910, p. 6.

The type of the Jurassic Reptile Morosaunis agilis redescribed, with a note on Camp-

Proc. U. S. Nat. Mus., vol. 32, 1907, pp. 151-165, pis. 12-13, text figs. 1-8.

Osteology of the Jurassic Reptile Camptosaurus, with a revision of the species of the genus,

and descriptions of two new species.

Proc. U. S. Nat. Mus., vol. 36, J909, pp. 197-332, pis. 6-20,

text figs. 1 to 48.

A New Dinosaur from the Lance Formation of Wyoming.
pub. 2184, 1913, pp. 1-5, 5 figs.
.

A New Ceratopsian Dinosaur from the Upper Cretaceous of Montana, with note on Hypa-

croBaurus.

Smiths. Misc. Coll., vol. 63, 1914, pp. 1-10, 3 figs.

Geegoey, W. K.
Reptiles.

of the Skeleton.
.

Homology of the "Lacrimal" and of the "Alisphenoid " in Recent andFossilBull. Geol. Soc. America, vol. 24, 1913, pp. 241-246.

Hatchee, J. B.

—

Smiths. Misc. Coll., vol. 61, No. 5,

Diplodocus Marsh, Its Osteology, Taxonomy, and jjrobable Hal)its, with a Restoration
Mem. Carnegie Mus., vol. 1, No. 1, 1901, pp. 1-63, 12 pis., 24 text figs.

The Jurassic Dinosaur Deposits near Canyon City, Colorado.

Annals Carnegie Mus., vol. 1,

1901, pp. 327-341, figs. 1-5.
.

Structure of the Fore Limb and Manus of Brontosaurus.

Annals Carnegie Mus., vol. 1, 1902,

p. 356-376, figs. 12 to 14.

—.

The Ceratopsia.

Hay, O. p.

Mon. 49, U. S. Geol. Stirv., 1907.

Bibliography and Catalogue of the Fossil Vertebrata of North America.

Bull. 179, U. S.

Geol. Surv., 1902, pp. 495-496.
.

On the Skull and the Brain of Triceratops, with notes on the brain cases of Iguanodon andMegalosaurus.

Holland, W. J.

Proc. U. S. Nat. Mus., vol. 36, 1909, pp. 95-108, pis. 1-3.

The Osteology of Diplodocus Marsh.

Mem. Carnegie Mus., vol. 2, No. 6, 1909, pp.

225-264, pis. 23-30, text figs. 1-30.

A review of Some Recent Criticisms of the Restoration of Sauropod Dinosaurs existing in theMuseums of the United States, with special reference to that of Diplodocus camegiei in the Carnegie
Museum. Amer. Nat., vol. 44, 1910, pi. 1, figs. 1-20.
HuENE, F. Baron. Die Dinosaurier der Europaischen Triasformation. Geol. und Pal. Abhandlungen,.

1907-1908.
tjber den altesten Rest von Omosaurus (Dacentrunis) im englischen Dogger.
buch, Jahrg. 1910, pt 1, 1910, pp. 75-78, pi. 7, 1 text fig.
.

Neues Jahr127

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

128
HuENE, F. Baeon.

Beitrage zur Kenntnis des Ceratopsidenschadels.

Neues Jahrbuch, Jalirg. 1911,

pt. 2, 1912, pp. 146-162, text figs. 1-10.

tjber die Zweistamniigkeit der' Dinosaurier,.

mit Beitragen zur KenntniB einiges Schadel.

Neties Jahi-buch, vol. 37, 1914, pp. 580-582, pi. 10.

Polacanthus foxi, a large undescrlbed dinosaur from the Wealden formation in the Isle

HuLKE, J. W.
of Wight.

Philos. Trans., 1881, pp. 653-662, pis. 70-76.

Some Dinosaur Remains, Part 2, Omosam-us.

.

Quart. JoiuTi. Geol. Soc. of London, vol. 43,

1887, pp. 699-702.
(Describes new species Omosaurus durobnveTisis.)

Extinct Monsters, 2d ed., 1893, pp. 110-115, pi. 10, text figs. 25-28.

H-UTOHiNSON, H. N.
.

Extinct Monsters and Creatures of Other Days, new ed., 1911, pp. 176-180, pi. 26, text figs.

61-64.

Huxley, Thomas H.

On Acanthopholis horridus, a New Reptile fi'om the Chalk Marl.

Geol. Mag.,

vol. 4, 1867, p. 65, pi. 5.

Jaekel, Otto.

Die AVirbeltiere, 1911, fig. 178.

On Vertebrata of the Mid-Cretaceous of the North West Territory.

Lambe, Lawrence M.

Contr.

Canadian Paleontology, Geol. Surv. Canada, vol. 3, 1902, pt. 2, pp. 23-81, pis. 1-21, text figs. 1-24.
.

On the Fore-Umb of a Carnivorous Dinosaur from the Belly River Formation of Alberta, and a

New Genus of Creatopsia from the same Horizon, with remarks on the integument of ?ome Cretaceous
herbivorous Dinosaurs.

Lankester, E. Ray.

Ottawa Naturalist, vol. 27, Jan., 1914, No. 10, pp. 129-135, pis. 13-17.

Extinct Animals, 1905, p. 208, fig. 150.

Leidy, Joseph. Notice of Remains of Extinct Reptiles and Fishes, Discovered by Dr. F. V. Hayden.
in the Bad Lands of the Judith River, Nebraska Territorj'. Proc. Acad. Nat. Sci. Phila., vol. 8, 1856,
pp. 72, 73.

Extinct Vertebrata from the Judith River and Great Lignite formations of Nebraska.
Amer. Philos. Soc, vol. 11, 1860, pp. 139-154, pis. 8-11.
.

Lucas, F. A.

—.

Trans.

Animals of the Past, 1901, pp. 106, 107, fig. 24.

A New Dinosaur, Stegosaurus marshi, from the Lower Cretaceous of South Dakota.

Proc.

U. S. Nat. Mus., vol. 23, 1901, pp. 591-592, pis. 23-24.
.

.

.

The Dinosaur or Terrible Lizards.

Science, vol. 16, 1902, p. 435 (Genus Eoplitosawus proposed).

Lull, Richard S.
.

.

Smiths. Report, 1901, pp. 646-647, pi. 4.

Animals Before Man in North America, 1902, pp. 170-171.
Dinosaurian Distribution.

Amer. Joum. Sci., vol. 29, 1910, pp. 1-39, text figs. 1-10.

Amer. Joum. Sci., vol. 29, 1910, pp. 201-210, figs. 1-11.
Stegosaurus ungulatus Marsh, Recently Mounted at the Peabody Museum of Yale University.

The Armor of Stegosaurus.

Amer. Joum. Sci., vol. 30, 1910, pp. 361-377, figs. 1-10.
ReptiUa of the Amndel Formation.

Maryland Geol. Survey, Lower Cretaceous,

1911, pp.

207-210, pi. 20, figs. 5, 6.

The Armored Dinosaur Stegosaunis ungulatus, recently restored at Yale University. Verhandlungen des VIII. Intemationalen Zoologen Kongresses zu Graz, 1912, pp. 672-681, figs. 1-4.
Lydekker, Richard.
.

Catalogue of Fossil Reptilia and Amphibia, pt. 1, 1888. pp. 176-180, figs. 31, 32.

Some recent restorations of dinosaurs.

Nature, vol. 48, 1893, pp. 302-304, with 5 figs, in the

text.
.

Cat. of Fossil Reptilia and Amphibia, vol. 4, 1900, p. 252.

Marsh, O. C. New Order of extinct Reptilia (Stegosauria) from the Jurassic of the Rocky Mountains.
Amer. Joum. Sci., ser. 3, vol. 14, 1877, pp. 513-514.
Notice of new Jurassic Reptiles. Amer. Joum. Sci., ser. 3, vol. 18, 1879, pp. 501-505, with pi.
.

3 and one text fig.
.

Principal characters of American Jurassic dinosaurs, pt. 3.

1880, pp. 251-259, with pis. 6-11.

Amer. Joum. Sci., ser. 3, vol. 19,

Marsh, O. C.

OSTEOLOGY OF THE AKMOEED DINOSAUEIA.

129

Principal characters of American Jurassic dinosaurs, pt. 4.

Spinal cord, pelvis andlimbs of Stegosaunis.

Amer. Journ. Sci., ser. 3, vol. 21, 1881, pp. 167-170, pis. &-S.

Principal characters of American Jurassic dinosaurs, pt. 5.

.

Amer. Journ. Sci., ser. 3, vol. 21,

1881, pp. 417-423, pis. 12-18.

Amer. Journ. Sci., ser. 3, vol. 23, 1882, pp. 81-86.

Classification of the Dinoeauria.

.

Principal characters of American Jurassic dinosaurs, pt.

Restoration of Brontosaurus.

6.

Amer. Journ. Sci., ser. 3, vol. 26, 1883, pp. 81-85, with pi. 1.

The classification and affinities of the dinosaurian reptiles.

.

A New Family of Dinosaurs.

.

Nature, vol. 31, 1884, pp. 68-69.

Amer. Journ. Sci., ser. 3, vol. 27, 1884, p. 165.

9.
The skull and dermal armor ofAmer. Journ. Sci., ser. 3, vol. 34, 1887, pp. 413-417, with pis. 6-9.

Principal characters of American Jurassic dinosaurs, pt.
Stegosaiirus.
.

Restoration of Stegosaurus.

Amer. Journ. Sci., ser. 3, vol. 42, 1891, pp. 179-181, with pi. 9.

.

Restoration of Stegosaurus.

Geol. Mag., ser. 3, vol. 8, 1891, pp. 385-387, pi. 11.

On the affinities and classification of the dinosaurian reptiles.

Amer. Journ. Sci., ser. 3, vol.

50, 1895, pp. 483-498, with pi. 10.

Dinosaurs of North America.

Sixteenth Ann. Rept. U. S. Geol. Siirvey, pt. 1, 1896, pp. 18(1-196, pis. 43-52.

Vertebrate Fossils of the Denver Basin.

Mon. 27, U.

Survey, 1897, pp. 498-502

S. Geol.

pi. 22, text fig. 52-57.

MooDiE, Roy L.

An armored Dinosaur from the Upper Cretaceous of Wyoming.

Kansas University

Science Bull., vol. 5, No. 14, 1910, pp. 257-273, pis. 55-59, one text fig.

A Dinosaurusok Atnezete es Szarmazasa.

NopcsA, F. B.IRON.

1901, pp. 193-224, pi.

Foldtani Kozlony, Budapest, vol. 31,

1.

Notes on British Museum, pt.

.

2,

Polacanthus.

Geol. Mag., vol. 2, 1905, pp. 241-250, pi. 12,

text figs. 1-8.

Omosaurus Lennieri un nouveau Dinosaurien du Cap de

.

la

Heve.

Bull. Soc. Geol.

Nor

mandie, vol. 30, 1911, pp. 1-20, pis. 1-7.
II.

Notes on British Dinosaurs, pt. 4.

Stegosaurus priscussp. nov.

Geol. Mag., vol. 8, No. 3,

1911, pp. 109-115, figs. 1-3; No. 4, 1911, pp. 145-153, figs. 4-9.

OsBORN, H. F.

A skeleton of Diplodocus.

Memoir Amer. Mus. Nat. Hist., vol. 1, 1899, pt. 5, pp.

191-214, pis. 24-28.
I.

.

chodon.

Crania of Tyrannosaurus and Allosaurus; II. Integument of the Iguanodont Dinosaur TraMemoirs of the Amer. Mus. Nat. History, new ser., vol. 1, pts. 1 and 2, 1912, pp. 1-54, pis.

1-10, text figs.

Mon. of the Fossil Reptilia of the Wealden and Purbeck Formations.

Owen, Richard.

Paleouto-

graphical Society, pt. 4, 1858, pp. 8-26, pis. 4-11.

Monograph of a Fossil Dinosaur (Scelidosaurus harrisoni Owen) of the Lower Lias.

.

Paleonto-

graphical Society, pt. 1, 1859, pp. 1-14, pis. 1-6; pt. 2, 1860, pp. 1-26, pis. 1-11.
.

Monograph of a Fossil Dinosaur (Omosaurus armatus Owen) of the Kimmeridge clay.

Paleon-tographical Society, 1875, pp. 45-93, pis. 11-22, text figs. 11-16.

Monograph on the Genus Omosaiu-us (continued).

Paleontographical Society, 1875,pp.

95-97, pis. 23-24.

Reichenbach, Ernst Freiherr Stromer von.

Lehrbuch der Palaozoologie,

vol. 2, Wirbeltiere,

1912, p. 121, fig. 118.

RiGQS, Elmer S.

Structure and Relationships of Opisthocoelian Dinosaurs.

Field Columbian Museum,Geol. Ser., vol. 2, No. 4, pt. 1, 1903, pp. 165-196, pis. 45-53, text figs. 1-18.

Wieland, G. R.

a New Armored Saurian from the Niobrara.

Amer. Journ. Sci., vol. 27, 1909, pp.

250-252, figs. l-7a.
.

Notes on the Armored Dinosauria.

Amer. Journ. Sci., vol. 31, 1911, pp. 112, 124, figs. ]-B.

130

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

WiLLisTON, S. W.

News Item.

.

Science, new ser., vol. 24, No. 622, Nov. 30, 1906, p. 711.

A new Armored Dinosaur from the Upper Cretaceous of Wyoming.

Science, new ser., vol.

22, 1905, pp. 503-504.

Woodward, A. S. Outlines of Vertebrate Paleontology, University Press, 1898, p. 212, fig. 131.
ZiTTEL, K. A. Handbuch der Palaeontologie, vol. 3, 1890, pp. 744-749, text figs. 650-660.
Text-Book Paleontology, English Trans., vol. 2, 1902, pp. 241-243, figs. 346-348.
and edited by Charles R. Eastman,.

.

Grundziige der Palaeontologie, pt. 2, 1911, pp. 293-295, text figs. 442-444.

Translated

EXPLANATION OF PLATES.
Plate 1.

Upper figure quarry " No. 1," Garden Park, Fremont County, Colorado.
From a photograph taken in 1901, showing the quarry as worked hy the Carnegie Museum of
See p. 24.

Pittsburgh, Pennsylvania.

Lower figure quarry "No. 1," Garden Park, Fremont County, Colorado.
From a photograph by I. C. Russell, taken at the time Felch was working here for Professor Marsh.
The man in the foreground is standing on the level from which the fossils have been removed. See p. 24.
Plate 2.

View of the upper or right side of the skeleton of Stegosaurus stenops Marsh. Type. Cat. No. 4934,
U.S.N.M. About -^ natural size. Shows the bones of the animal just as they were found and as now
exhibited (p. 106).

The nonshaded portions represent restored parts.
Plate 3.
Marsh.

Outline of the skeleton of Stegosaurus^ natural size

Designed as a key to plate 2.

Scale about(p. 106).

Ac, acetabulum.

0, dermal ossicles.

At, atlas.

P3 to Pl7, dermal plates, three to seventeen.

C4, fourth caudal.

PS,

C17, seventeenth caudal.

sacrum).

Ca, carpus.

Pu, pubis.

presacrals

Cer 9, ninth cervical.

R, radius.

Ch, chevron.

S, dermal spine.

Co, coracoid.

Sc, scapula.

DS, dorso-sacral (No. 27).

(numbered

from

head

towardT, tibia.

F, femur.

U, ulna.

Fb, fibula.

//,V, metacarpals two and five.

— indicates direction of water current that washedH, humerus.

>,

over the specimen.

II, ilium.
Is, ischium.

Plate 4.

View of the lower or left side of the skeleton of Stegosaurus stenops Marsh. Type. Cat. No. 4934,
U.S.N.M. About ^-5 natural size. Shows the position of the dermal plates in relation to the other parts
Since this drawing was made the contacts of many additional parts have been found,of the skeleton.
which will account for various inconsistencies when compared with plates 2 and 3.
C2, second caudal.

P,3 to P,o dermal plates, one to sixteen.

C17, seventeenth caudal.

R, radius.

Ca, carpus.

i?', ribs.

Cer 6, sixth cervical.

S, sacrum.

OS, caudo-sacral.
Ch, chevron.

S2, third sacral vertebra.

F, femur.

8c,? (may represent fragment of the right scapula).

H, humerus.

T, tibia.

Is,Sc, scapula.

ischium.

U, ulna.
II, V, metacarpals two and five.

II, ilium.

0, dermal ossicles (improperly ])laced.
plate 3, for correct position).

See 0,

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

132

Plate 5.
Skull of Stegosaurus stenops Marsh. Side view. Type. Cat. No. 4934, U.S.N.M. J nat. size,a, anterior nares; an, angular; ar, articular; b, orbit; c, infratemporal fossa; d, dentary; j, jugal; I,
lachrymal; m, maxillary; n, nasal; oc, occipital condyle; p. ar, prearticular; pd, predentary; pf, prefrontal;

pm, premaxillary; p.o, postorbital; p. oc, paraoccipital process; po. so, postsupraorbital: p. so,presupraorbital;q.

quadrate; qj, quadratojugal; s. splenial; sn. Burangular; sq. squamosal.

See p. 27.

Skull of Stegosaurus stenops Marsh. Top view. Type. Cat. No. 4934, U.S.N.M. J nat. size.
supratemporal fossa;/, frontal; I, lachrymal; m, maxillary; n, nasal; p, parietal; pf, prefrontal;
pm, premaxillary; po, postorbital; p. oc, paraoccipital process; po.f, postfrontal; po. so, postsupraorbital;
See p. 27.
p. so, presupraorbital; q, quadrate; qj, quadratojugal; so, supraoccipital sq, squamosal.

e,Plate 7.
Skall of. Stegosaurus stenops Marsh.

Type.

Cat. No. 4934, U.S.N.M.

^ nat. size.

Inferior view.

an. angular; ar, articular; d. dentary; oc, occipital condyle; p. ar, prearticular; pd, predentary; pi,palatine; pm, premaxillary; p. oc, paraoccipital process; pt, pterygoid; s, splenial;
Drawn under the direction of Prof. O. C. Marsh, with slight modifications.

j).

vomer.

See p. 27.

Plate 8.
Skull of Stegosaurus stenops Marsh. Longitudinal section. Tyjje. Cat. No. 4934, U.S.N.M.
J nat. size, a, anterior nares; an, angular; ar, articular; d, dentary;/, frontal; /.m, foramen magnum;m, maxillary; n, nasal; oc, occipital condyle; p, parietal; p. ar, prearticular; pd, predentary; pm, premaxillary; p. oc, paraoccipital process; pt, pterygoid; q, quadrate; s, splenial.
Drawn under the direction of Prof. O. C. Marsh, with slight modifications.

See p. 27.

StuU. oi Stegosaurus stenops Msash. Cat. No. 4934, U.S.N.M. J nat. size. Type. (1) Front view;a, anterior nares; an, angular; ar, articular; d, dentary; /, frontal; fm, foramen magnum;(2) back view,lachrymal; n, nasal; oc, occipital condyle; p, parietal; p. art, prearticular; pd, predentary; pf, prepm, premaxillary; po, postorbital; p. oc, paraoccipital; po. f, postfrontal; po. so, postsupraorbital; p. so, presupraorbital; pi, pterygoid; q. quadrate; sa, suraugular; so, supraorbital, sq, squaI,frontal;Both figures after Professor M?rah, with slight modifications.

Skull of Stegosaurus armalus Marsh.?

Cat. No. 4936,

See p. 27.

U.S.N.M.

1.

Top view; e, supratemporal

fossa; /, frontal; fm,. foramen magnum; ns, sutural surface for nasals; oc, occipital condyle; p, parietal;po, postorbital; ps, sutiu^l surface for prefrontal; so, supraoccipital.

noid;

2.

Ventral view; al. sp, alisphebrain case; or. sp.

6, orbit; e, supratemporal fossa; oc, occipital condyle; ol, olfactory region of theII, III, and IV exit of second, third, and fourth cranial
orbitosphenoid; pp, paraoccipital process.
nerves. 3. Longitudinal section through brain case; /, frontal; /', exit of II cranial nerve; fm, foramen

magnum; oc, occipital condyle; ol. exit of olfactory nerve; op, for optic lobe; p, parietal; pi, pituitary
fossa; ps, presphenoid; so, supraoccipital.

4.

Outhne of skull of Stegosaurus armatus with brain castch, cerebellum; e, supratemporal fossa; m,medulla; ol, olfactory lobes. 5. Brain cast of the same; c, cerebral hemispheres; ch, cerebellum; m,medulla; ol, olfactory lobes; on, optic nerves; op, optic lobes; pi, pituitary body. All figures are ^ nat.
size.
Drawn under the direction of Prof. O. C. Marsh with slight modifications. The species identifiSee p. 41.
cation is that of Professor Marsh.

in position; seen from above; c,cerebral hemispheres;

133

OSTEOLOGY OF THE ABMOKED DINOSAUKIA.
Plate 11.

Cervical vertebrae and nuchal plates of Stegosaurus stenops Marsh. Type. Cat. No. 4934, TJ.S.N.M.
Shows
at, atlas; c^, sixth cervical; p. 1 to p. 5, dermal plates one to five, inclusive.
See p. 92.
the relations of these bones as found in the matrix. From a photograph.

About ^ nat. size,

Plate 12.
Fig. 1. Posterior dorsal i)late of Sic^osaMmsstenop* Marsh. Cat. No. 4714, U.S. N.M. inat.size. Viewed
from the side. This plate can probably be correlated with No. 13 of No. 4934. This is plate

No 95, diagram 5, quarry 13.

See also plate 37.

a,anterior border;

6,

posterior border.

See p. 93.
2. Ventral view of the same.
Drawn under the direction of Prof. O. 0. Marsh.

Plate 13.
Cat. No. 4714, TJ.S.N.M. i nat. size. Viewed
from the side. This is the largest plate of the series and is correllated wdth No. 14 of No. 4934.
This is plate No. 10, diagram 5, quarry No. 13. See plate 37, also same as fig. 4, plate 24.
See p. 93.
o, anterior border; 6, posterior border.

Kg. 1. Anterior caudal plate of Stegosaurus stenops Marsh.

2.

Ventral view of the same.

Drawn under the direction of Prof. 0. C. Marsh.
Plate 14.
dermal plates of Stegosaurus stenops Marsh. Type. Cat. No. 4934, TJ.S.N.M. Plates
The even numbers represent plates pertaining to the row of the right side; the1 to 14 in sequence.
Series of.

odd to those of the left. About } natural size.
Drawn by Mr. George E. Roberts, under the direction of Dr. F. A. Lucas with additons.

PubUshedby permission of the TJnited States Geological Survey.

See p. 93.

Plate 15.
nat. size.
Cat. No. 4714, U.S.N.M.
-J(Jaudal vertebrae and spines of Stegosaurus stenops Marsh.
a, right anterior spine; 6, left anterior spine; c, left posterior spine; d, rightspine of posterior pair; d', basal half of same spine, removed in order to show underlying caudals; e,Seen from the right side,

chevron; /, terminal vertebra; g, twelfth caudal from distal end.
Mar.sh.

Drawn under direction of Prof. O. C.
See p. 95.

'

Plate 16.
Caudal vertebrae, spines and plates of Stegosaurus stenops Marsh. Cat. No. 4288, U.S.N.M. Seenfrom the left side. \ nat. size. After Marsh, a, right spine of anterior pair; 5, left spine of anterior
pair; c, small caudal plate; rf, chevron bones; e, right spine of posterior pair; /, left spine of posterior
pair; g, terminal vertebra; h, twenty-third caudal vertebra from distal end.
The bones represented here are essentially in the position in which they were found. Identified
and figured by Prof. O. C. Marsh as Diracodon laticeps Marsh. Drawn under the direction of Prof.
See p. 95.
O. C. Marsh.

Plate 17.
Dermal tail spine of Stegosaurus stenops Marsh. Cat. No. 6135, U.S.N.M. } nat. size. (1) and
From quarry No. 13,
It undoubtedly belongs to the anterior pair.
(2) side views; (3) posterior view.
See p. 95.
diagram 5; No. 31i. See map, plate 37. Dra-mi under the direction of Prof. O. C. Marsh.

Plate 18.
Type. \ nat. size.
Cat. No. 4937, U.S.N.M.
external view; (2) internal view; (3) anterior view; (4) section taken at first fracture above thea, anteriorinfigure
shown
2.
base,
above
the
fracturebase in figure 2; (5) section taken at second
sulci; s, roughened
sulci; 6, ridge dividing the basal surface; p, posterior sulci; r, ridge between
Drawn under the direction of O. C. Marsh.
surface for cartilaginous union with spine of opposite side.

Dermal tail spine of Stegosaurus sukatus Marsh.

(1)

See p. 109.

51873"— Bull, S9— 14

10.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

134

Plate 19.
Skull and sacral cavity of Slegosawus.

Viewed from the rigiit side. Type.
Reproduced from a photograph.
Stegosaurus sp. Cat. No. 7380, U.S.N.M. -} nat. size.

Kig. 1. Skull of Stegosaurus

stenops Marsh.

U.S.N.M., about \ nat.
Sacral cavity of2.

a,anterior;c,Oat. No.

size.

sacral ca^dty; p, posterior end.

4934,

See p. 27.
Vent^^l view.
See p. 56.

Plate 20.
Right coracoid, humerus, ulnae, and radii of Stegosaurus
Cat. No. 7411, U.S.N.M.
^nat. size. Viewed
See p. 67.
externally, a, anterior border; h, glenoid fossa; c, coracoid foramen.
Right humerus of Stegosaurus stenops Marsh. Cat. No. 4929, U.S.N.M. |^ nat. size. Front
view, h, head; r, radial crest; s, supinator ridge.
See p. 68.
Right ulna of Stegosaurus. A, Cat. No. 4937, U.S.N.M. Type of Stegosaurus sulcalus Maxsh.
Adult: B, Cat. No. 7401, U.S.N.M. Juvenile. Comparative side views to show the great
Seep. 69.
difference in the development of the olecranon process. Both ^ nat. size.
Right radii of iStej'osaMJTts. J., Cat. No. 4937, U.S.N.M. Type oi Stegosaurus sulcatus Mstrsh.
front
views.
No.
U.S.N.M.
Juvenile.
Comparative
Both
Adult: B, Cat.
7401,
} nat.
See p. 70.
size.

Pig. 1. Right coracoid of Stegosaurus stenops Marah.

2.

3.

4.

Plate 21.
Scapula of Stegosaurus stenops, metacarpals of Stegosaurus sulcatum, and hind foot of Stegosaurus.
Fig. 1. Right hind foot of iSteg'osoMnts, sp.

in situ.

I,

II, III, digits one,Cat. No. 4280, U.S.N.M.

two, and three.

About i- nat. size. Shown as foimd

S, sesamoid.

2.

Cat. No. 4937, U.S.N.M.
Metacarpals of Stegosaurus sulcatus Marsh.
Right fore foot, front view. 1, 2, 3, 4, and 5 metacarpals one to five.

3.

Left scapula of Stejrosourus stenops Marsh.
5',

Cat. No. 7371, U.S.N.M.

Type.

| nat. size

glenoid fossa.

See p. 88.
} nat. size.
See p. 72.
Outer view.
See p. 66.

Plate 22.
Skull of Ileloderina suspectuiii and dermal ossicles of Stegosaurus stenops Marsh.
Fig. 1. Tuberculated upper surface of the skull of Eeloderma suspectum, the Gila monster, for comparison with the dermal tubercles of StejrosaMrits. About nat. size. AfterOsbom. Seep. 91.

Dermal ossicles of Steg'osawrMS stenops Marsh.

2.

Cat. No. 7615, U.S.N.M.

J nat. size.

Shown as found in situ.

view.

External

See p. 91.

Cat. No. 4934, U.S.N.M.
3. Dermal ossicles of Stegosaurus stenops Marsh.
Internal side of ossicles. Portion of those shown in plates 2 and 4.

Type,

i nat. size.

See p. 91.

Plate 23.
Dermal plates of Stegosaurus stenops Marsh, and Stegosaurus sulcatum Marsli.
Figs 1.

,2,

and 3 N uchal plates of Stegosaurus showing the change in shape and comparative sizes from the.

Belongs to the type of Stegosaurus sulcatus Marsh;
All -J nat. size.
See p. 92.
Cat. No. 7584, U.S.N.M. Jnat. size.
Seeplate 37, map of quarry 13, diagram 4, No. 211. This plate is correlated with No. 6 of No.
See p. 92.
4934. See also plate 14.
Dermal plate from region of shoulder of Stegosaurus stenops Marsh. Inner view. Cat. No.
See plate 37, map of quarry 13, diagram 4, No. 209. This platenat. size.
7584, U.S.N.M.
(1) Cat.

skull posteriorly.
(2) and (3) Cat.

4.

5.

No 7615.

No. 4937.

All in the U. S. National Museum.

Posterior nuchal plate of iS teg'osaurus stenops Marsh.

-J-

See p. 92.
with No. 8 of No. 4934. See also plate 14.
Dermal plate from sacral region of .StegrosaurMS stenops Marsh, ('at. No. 4714, U.S.N.M. -J nat.
This
plate
is
correlatedwithNo.
diagram95.
plate
quarry
size.
13,
5,
See
37, map of
See p. 93.
No. 13 of specimen No. 4934. See also plate 14.
is correlated

6.

.

OSTEOLOGY OF THE ARMORED DINOSAURIA.

136

Plate 24.
Dermal plates from tail of Stegosaurus stenops Marsh.
Fig. 1. Distal tail plate of Stegosaurus stenops Marsh. Cat. No. 4714, U.S.N.M. About
I nat. size.
Plate 37, map of quarry 13, No. 177, quarry 13, diagram 5; also 177, fig. 58. This plate is2.

3.

correlated with No. 17 of specimen No. 4934, plate 3.
Dermal tail plate of Stegosaurus stenops Marsh. Cat. No. 4714, U.S.N.M.

See p. 93.
Seeplate 37, map of quan-y 13, diagram 5, No. 76; also 76, fig. 58. This plate is correlated with
No. 16 of specimen No. 4934, plate 3.
See p. 93.
Dermal plate of Stegosaurus stenops Marsh. Cat. No. 4714, U.S.N.M.
nat. size,
See plateThis plate is correlated with No. 15 of specimen No.
37, map of quarry 13, diagram No. 75.
4934. See plate 3; also 75, fig. 58.
See p. 93.
Dermal -tail plate of Stegosaurus stenops Marsh. Cat. No. 4714, U.S.N.M. J nat. size. See
plate 37, map of quarry 13, diagram 5, No. 10; also 10, fig. 58. This plate is correlated with
No. 14, specimen No. 4934, plate 3.
See p. 93.
J nat. size.

-J-

4.

Plate 25.
Fibula, iscliium, and dermal tail spines of Stegosaurus.
Fig. 1.

Anterior dermal tail spine of Stegosaurus stenops Marsh.
Lateral view.

2.

Cat. No. 6629, U.S.N.M.

See p. 95.
Cat.

No. 6629, U.S.N.M.

Oblique lateral view. Juvenile.
3. Posterior dermal tail spine of Stegosaurus sulcatus Marsh.
|-

4.

nat. size.

5.

size,

b,

See p. 95.

Type.

Cat. No. 4937,

(

^at.

U.S.N.M.

See p. 110.

Type D 54, University of Wyoming cjollection.

.

process which meets the pubis;

Left fibul;\ of Stegosaurus sp.

nat. size.

^

Viewed from the side.

Left ischium of Stegosaurus longispinus Gilmore^ nat.

J nat. size.

Juvenile.

Posterior tail spine of Stcgosaitnis stenops Marsh.

i,

iliac

No. 7389, U.S.N.M.

articulating border;^ nat. size.

s,Litemal view.

symphysis.
See p. 113.
See p. 85.

Plate 26.
Scapula, coracoid, and humerus of BoplUosaurus marsM ( Lucas)

humerus of Hoplitosaurus marshi (Lucas). Type. Cat. No. 4752, U.S.N.M.
About J nat. size.
See p. 115.
Proximal half of the left humerus of Hoplitosaurus marshi (Lucas).
Type. Cat. No. 4752,
U.S.N.M. About J nat. size. Front view.
See p. 115.
Portion of right scapula and coracoid of Hoplitosaurus marshi (Lucas). Type. Cat. No. 4752,
U.S.N.M. J nat. size. Lateral view, a, acromion process; c, coracoid; g. glenoid fossa.

Fig. 1. Distal half of2.

3.

See p. 115.

Plate 27.
Dermal elements of Hoplitosaurus marshi (Lucas). Type. Cat. No. 4752, U.S.N.M. Mass ofdennal scutes and ossicles shown as found in situ. Less than J nat. size.
See p. 118.

Dermal plate of Hoplitosaurus marshi (Lucas). Type. Cat. No. 4752, U.S.N.M.
External view, probably represents the type of spine adjacent to the shouldei; region,Jnat. size.

Seep. 119.

Plate 2!i.

Dermalplate of Hoplitosaurus m,arshi (Lucas).

view; (2) posterior view of same.

Dermal plateof

Hoplitosaurus

view: (2) posterior view of same.

Type.

Cat.

N(j.

4752,

U.S.N.M.

Both figs. J nat. size.

marshi (Lucas).

Both figs. J nat. size.

(1) lateralSee p. 120.

Type.

Cat.

No. 4752, U.S.N.M.

(1) lateralSee p. 120.

BULLETIN 89, UNITED STATES NATIONAL MUSEUM.

136

Plate 31.
Dermal bones of unidentified reptiles.
Fig.

1.

Dermal ossifications o£ unidentified reptiles, (a) Cat. No. 7804, U.S.N.M.; (b) Cat. No. 7805,
U.S.N.M. Lateral view. Both natural size. Both from Lance formation of Wyoming.

2.

Dermal scutes of Hierosaurus ?.

See p. 122.
Cat. No. 7726

U.S.N.M.

-|

nat. size.

Dorsal view of all.

From Big Horn County, Wyoming

See p. 122.

Dermal scute of iinidentified dinosaur from tlie Lance formation of Montana.
U.S.N.M. J nat. size. Dorsal view.
4. Dermal scute of unidentified dinosaur from the Lance formation of Wyoming.
U.S.N.M. 4 nat. size. Dorsal view.
3.

Cat. No. 7724,

See p. 122.
Cat. No. 7243,

See p. 122.

Plate 32.
Restorations of Stegosaurus.

Upper figure. Restoration of Stegosaurus ungulatus Marsh, 1891.

rh nat. size.

Lower figure. Life restoration

By J. Smit, 1893.

After Marsh.

See p. 122.
ofStegosaurus ungulatus Marsh.

Hutchinson.

After Rev. H. N.

See p. 123.

Plate 33.
Restorations of Stegosaurus.

Upper figure. Life restoration of Stegosaurus. By Frank Bond, 1899. Drawn under the direction ofProf. W. C. Knight.
See p. 123.
Lower figure. Life restoration of Siegfosaunts imyuiaiits Marsh. By Charles R. Knight, 1901. After F. A.
Lucas.

See p. 123.

Plate 34.
Restorations of Stegosaurus.

Upper figure. Life restoration of Stegosaurus ungulatus Marsh. By G. B. Roberts, 1901. See p. 123.
Lower figure. Statuette of Stegosaurus stenops Marsh. By Charles R. Knight, 1903. After model in
U. S. National Museum.
See p. 123.
Plate 3.5.
Restorations of Stegosaurus.

Upper figure. Restoration of Stegosaiirus ungulatus Marsh, by T. Smit.

After Rev. H. N. Hutchin-son, 1911.

Lower figure. Life restoration of Stegosaurus, 1905.

After E. Ray Lankester.

See p. 123.
See p. 123.

Plate 36.
Restorations of Stegosaurus.

Upper figure. Life restoration of Stegosaurus ungulatus Marsh, by R. S. Lull, 1910.

After R. S. Lull.

See p. 124.

Lower figure. Mounted skeleton of Stegosaurus ungulatus Marsh, in the Peabody Museum, New Haven,
Coim. (Cat. Nos. J.853 and 1858), oblique front view. 1910. Length, 19 feet 5 inches. After
R. S. Lull.

See p. 124.

Plate 37.

Map of quarry 13, near Como, Albany County, Wyoming. Worked under the direction of Prof. O. C.
Marsh, from 1879 to 1887, inclusive. Scale about 4J feet to the inch. This map shows the relative positions of all the bones found in diagrams 1, 2, 3,

4,

being designated by the original quarry numbers.

Brown.

5,

7, 8, 11, 12, and 13, each bone or group of bones
Compiled from quarry maps made by Mr. FredSee p. 4.

U. S.

NATIONAL MUSEUM
BULLETIN 89

Quarry, Garden Park, Fremont County, Colorado.
'late see page 131.

PL.

1

U. S.

NATIONAL MUSEUM

BULLETIN 89

•
/ ^

PL. 2

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 3

U. S.

NATIONAL MUSEUM
BULLETIN 89

PL.

4

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 5

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 6

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 7

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 8

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 9

U. S.

NATIONAL MUSEUM
BULLETIN 89

Skull and Brain of Stegosaurus armatus?
For explanation of plate see page 132.

PL. 10U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 11BULLETIN 89
U. S.

NATIONAL MUSEUM

Plate of Stegosaurus stenops.
For explanation of platesee page 133.

PL. 12

U. S.

NATIONAL MUSEUM

BULLETIN 89

m
A'?
-'

y

J

V

Plate of Steqosaurus stenops.
For explanation of plate see page 133.

•\m

f /'£ ^^_*-

-

"'-J'

^

PL. 13

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 14

Dermal Plates of Steqosaurus stenops.

U, S.

NATIONAL MUSEUM

BULLETIN 89

PL. 15

U. S.

NATIONAL MUSEUM

BULLETIN 89

PL. 15

U. S.

BULLETIN 89

NATIONAL MUSEUM

Dermal Spine of Stegosaurus stenops.

PL. 17

U. S.

BULLETIN 89

NATIONAL MUSEUM

Dermal Spine of Stegosaurus sulcatus.
:

plate see page 133.

PL. 18

U. S.

BULLETIN 89

NATIONAL MUSEUM

Skull and Sacral Cavity of Stegosaurus.

PL. 19

U. S.

NATIONAL MUSEUM

BULLETIN 89

CoRAcoiD, Humerus, Ulna, and Radii of Steqosaurus.
=

LATE SEE PAGE 134.

PL. 20U. S.

BULLETIN 89

NATIONAL MUSEUM

Scapula, Fore and Hind Foot of Stegosaurus.

PL. 21

U. S.

BULLETIN 89

NATIONAL MUSEUM

Skull of Heloderma suspectum and Ossicles ofI

Steqosaurus stenops,

OF PLATE SEE PAGE 1 34.

PL. 22

U. S.

BULLETIN 89

NATIONAL MUSEUM

DERMAL PLATES OF STEGOSAURUS STENOPS AND S.
For explanation of plate see page 134.

SULCATUS.

PL. 23

U. S.

NATIONAL MUSEUM

BULLETIN 89

Dermal Plates of Steqosaurus stenops.
.late see page 135.

PL. 24

U. S.

BULLETIN 89

NATIONAL MUSEUM

Fibula, Ischium,

and Dermal Tail Spines of Stegosaurus.

For explanation of plate see page 135.

PL. 25

U. S.

NATIONAL MUSEUM

BULLETIN 89

Scapula, Coraooid, and Humerus of Hoplitosaurus.
For £PL. 26

U. S.

NATIONAL MUSEUM

BULLETIN 89

Dermal Bones of Hoplitosaurus.
For explanation of plate see page 135.

PL. 27

U, S.

NATIONAL MUSEUM

BULLETIN 89

Dermal Plate of Hoplitosaurus.
For explanation of plate see page 135.

PL. 28

U. S.

NATIONAL MUSEUM

BULLETIN 89

Dermal Plate of Hoplitosaurus.
1

OF PLATE SEE PAGE 136.

PL. 29

U. S.

NATIONAL MUSEUM

BULLETIN 89

Dermal Plate of Hoplitosaurus.
'late see page 135.

PL. 30U. S.

BULLETIN 89

NATIONAL MUSEUM

Dermal Bones of Unidentified Reptiles.
For explanation of plate see page 136.

PL. 31

U. S.

BULLETIN 89

NATIONAL MUSEUM

Restorations of Steqosaurus.
For explanation of plate see page 1 36.

PL. 32

U. S.

BULLETIN 89

NATIONAL MUSEUM

Restorations of Steqosaurus.
For explanation of plate see page 136.

PL. 33

U. S.

BULLETIN 89

NATIONAL MUSEUM

Restorations of Steqosaurus.
For explanation of pu\te see page 136.

PL.

34

U. S.

NATIONAL MUSEUM

BULLETIN 89

Restorations of Steqosaurus.
•

PLATE SEE PAGE 1 36.

PL. 35

U. S.

NATIONAL MUSEUM

BULLETIN 89

Restorations of Stegosaurus.
For explanation of plate see page 136.

PL.

INDEX[Figures in black-face type indicate descriptions.]

Acantliopholis

101, 116, 118

Acetabular border57

Acetabulum

55, 77-79, 82, 107

Alcova, fossil remains discovered near

AHsphenoids

27, 30, 31, 32, 42, 43
32, 42, 43

Allosaurua

66

on Ankylosaurus
Brown, Fred, fossil remains collected by.

66, 115.

26.

work of

Ill

Alligator

3,4

Gap Station, South Dakota,
specimens found near

Buffalofossil

114

2
C.

25

fragilis

AngularAnkylosaurus
Armor, dermal

27, 37, 38, 39

44, 66, 100, 115, 118
64, 91-100, 101-103, 105, 107,

114, 118-131, 122-123, 124, 126

arrangement of

96-99

gular

114,118

nuchal114, 115

Articular

27, 37, 39

Arundel formation
Ashley, E. G., work of
Astragalus

Brown, Barnum, on Triceratops

30
2

84, 85, 86, 87, 101, 103, 105, 109Atlantosaurus beds

105

Atlas

45, 46, 47, 53, 63, 105, 124

Auditory meatus, internalAxis

33
45, 56, 47, 53, 63, 105

B.
Baflioccipital

27, 38, 29, 30, 41

Calcaneum

84-86, 87, 103, 105, 109

Calico Canyon, South Dakota,

fossil speci-

mens found in

114

Camptonotidae
Camptosauridae
Camptosaurus

109
30, 84, 109
2, 27-30, 32-34, 37, 39^2, 44,

45, 47, 50, 51^61, 66, 84, 114, 125

browni Gilmore
depressus Gilmore
dispar Marshmedius Marshnanus Marsh
Canal, haemal

Canon

City,

4
4, 114

4, 88

4, 25

4
61

Colorado,fossilfound near
Carapace
Carbon County, see Wyoming
Carinaspecimens
24, 105

118
100

Basisphenoid27, 28, 30, 31, 32, 36, 41-43
Beecher, C. E
97
Beekley, A. L., fossil remains discovered by122

Carpals

71, 73, 83, 101, 109, 125

Carpus70-73, 75, 105

Berger, Frederick, drawings by

Caudals, see Vertebrae.

2

Big Horn County, see Wyoming.
101

Bond, Frank, restoration by
Boss, N. H., work of123
2

Brachial enlargement, see Neural Canal.

Brachyceratops montanensis Gilmore

102, 103

Bressler, C. V., work of2

Brontosaurus

25, 76, 88, 90

excelsus Marsh2, 88

Broom, R

51873°— Bull. 89—14

32
11

54, 55, 57, 59

Cavity, medullary(jgCentrum

54, 57, 62, 117

Ceratodus giintheri Marsh

25

Ceratopsia
32, 8843, 44, 56, 57, 101

cavity30, 43,

Caudo-sacral

Birds

Brain, description of

Carotid arteries

Ceratopsian41, 77, 83, 110

32, 68, 84, 122, 125, 126

Ceratosaurus nasicornis Marsh25

Cerebellum

43

Cervical vertebrae

Chevron47-49,50, 91, 102, 124, 125
60, 61, 62, 98, 103, 105

Claosaurus

66

Claw

90

.

138
59

Cleats122
Cody, Wyoming, fossil specimens found near25
CoeluruB agilis Marsh
4fragilis MarshColorado, fossil remaLns discovered in. i . . 101, 103
Fremont County, fossil remains discov-ered in

105, 106-

Como, Wyoming, fossil remains discovered
2, 109near

Como Bluff, location

Dryolestes gracilis Marsh.

25

Dryosaurus

30
altus Marsh. .

Elephant
Elephas76, 8136

Europe, Stegosauria from101

Exoccipital

27, 38, 29, 30, 41

F.

84,113

inner (internal)

82,116,117.outer (external)

82,101,116,117
68, 115

radial.

68,115ulnar

Converse County, see Wyoming.
Cope, E. D., fossil remains described by.

Facets.

.

101

65, 66, 67, 68, 105, 114, 115

Coronoid37, 39Crat^,eomus

101

Crest, enemial

84radial

68

CrocodUia

32, 41, 63, 100, 115, 123D.

Dacentruius

102

Dart, A-. C, fossil remains collected by. . .

.

IllDarton, N. H., fossil remains collected by.

.

114

by

68

trochlear

68

80-83, 84, 88, 101, 103, 105, 108, 111, 113, 114

71

arterial

coracoid

67, 115

external mandibular

39, 10242

magnum28-30, 41

mental37
43
31, 82, 42

ovale

pubic
Foramina, lesser

spines, see Spines.

79
41-43

sacral56

Fore limbs

57, 68104r-113

47^9, 52, 54, 56, 57, 63, 98, 113, 117
68, 70, 73, 75-77, 86-89, 101, 103, 125

lower temporal

103, 116

olecranon

105
38
115

pituitary

30, 43supraorbital

33, 41mandibular

28,

camegii Hatcher

88
25

longus Marsh

71, 101, 108

laticeps Marsh4, 104, 109

Dollo, Louis, on ancestry of Stegosaurus
fossil27, 32, 40, 41

infratemporal43, 63, 64, 67, 76, 81, 82, 88, 101, 117, 125

Diracodon

67, 68, 115

Fossae, glenoid

121-133

Dinosaur armor from Lance formation
Dinosauria
Diplodocus

Montana,

116, 117, 118, 121. 122

Fergus County, see Montana.
Fibula84, 85, 86-88, 101, 103, 105, 107, 109
Foot, fore
68, 70-77, 107, 109, 125
86-90, 106
hiad
Foramen, anterior condyloid
29, 41, 42

91, 93

ossicles26, 105, 106

55,68,

olfactory

plates, see Plateg.

Dovetail Butte,byFenestra ovalia

Dermal, armor, see Armor.

Digits24, 25fossil remains collected

Femur

lacerum posterius

Depressions, anconeal

.

64
33

Felch, M. P., discovery of fossil specimens

27, 37, 38, 44, 105.

60, 61, 117

tubercularDentition, see Teeth.

Description of species

62, 63, 87
51, 64chevron115

Deltoid ridge

Dentary,

capitular

Facial nerve

Coracoids

126

Bupratemporal28, 31, 32, 35, 40, 105
Fremont County, see Colorado.
Frontals
27, 30, 31, 33, 33, 40, 43, 105.

remains

found near
Doyle, Arthur Conan, restoration publishedby43, 75, 125

Epipterygoid

2CondylesDiapophyses.

4

E.

G.
122

Garden Park,
123

82

GalluBinColo.,

fossilremajna foxmd
105,106

139^-

Geare, R. I., restoration published by

123

GUes, G. B., work ofGilmore, C. W., on Camptosaiirus

239

on Tlaescelosaurus

66
121

.

Girdle, pectoral

Glyptops plicatulus (Cope)4, 25

Goniopholis sp
Groove, radial

4, 25

Jaw, lower

principal measurements

Jugal

Jugularvascular

92, 93, 99

91, 93posterius.

Jurassic formation

58, 101, 105, 109, 111

K.

Kenney, J. L., fossil remains collected by.. 3, 109
Knight, Charles R., restorations by

H.

by

52

25

90
41
67

.

Labrosaurus ferox Marsh25
Lachrymal
27, 32, 33, 34, 41
Lakota formation
114
Lambe, L. M., on dermal covering of Ceratopsia

126

Lamina

56

102

91

Hewett, D. F., fossil remains collected by..
122
Hierosaurua
118
Hind limbs
57,80,82,83
Holland, W. J., on Diplodocus
63, 64
Hoplitosaurus
102, 114-116, 118, 120, 122
marshi (Lucas)
111-131, 122
Horncore, supraorbital
110

Homy covering

123

25

30,42
.

tion of24
79, 121, 122Hay, O. P., on Triceratops
on classification Stegosauridae
Heloderma, skull

Knight, W. C, restoration made under direc-

25

114,122

on Brontosaurus
on Ceratopsia
on Diplodocus
on dinosaur beds
on direction of workon Triceratops

Lance formation
121, 122
Lankester, E, Ray, restoration published by
123
Laosaurus

109
gracilis Marsh25
101,103,107,121,125
101
Lucas, F. A., fossil remains described by...
114

Limbs, forehind

on dermal armor Stegosaurus.

:

Humeruson Hoplitosaurus
on Stegosaurus

39

work of29, 39Lull, R. S., figures byof.

on dermal armor Stegosaurus. . .

Stego-

40

Hypoglossal nerve

29, 41

Hypsilophodon foxii Hulke
Hypsu'ophus discursus Cope

33
101, 102

seeleyanus C!ope

101

I.

97,

98, 100, 103

on femur of Stegosaurus
on mounted skeleton of Stego-

Huxley, on Acanthopholis118
on family Scelidosauridae
114
Hylaeosaurus
101, 115, 118, 120

saurus83

124, 125, 126

on neural cavity of Stegosaurus.
57
on restoration of Stegosaurus. .
124
on ribs of Stegosaurus
64
on teeth of Stegosaurus
44
on vertebrae of Stegosaurus
51
work of1
102
Lydekker, R. on Omosaurus
on Stegosaurus
38, 102.

,28, 32, 39, 41, 45, 61, 81

bemissartensis Boulenger

lUum

1

123

Hyoid

40,

97,98,99
fossil remains described by. ..
30
on brain of Stegosaurus
43, 4467,

saurus102, 118, 119

94, 96, 102, 106, 123

68, 69, 83, 103, 105, 109, 114, 115, 116, 125

Hutchinson, H. N., restoration

95,

96, 97, 102

99

Huene, F. von, on Stegosaurus
on Triceratops

Iguanodon

102,
106, 123, 125

Haplocanthosaurus
Haplocanthoaaurus priscus Hatcher
utterbacki Hatcher. ....
Hatcher, J. B., fossil remains collected.

40
27, 32, 33, 34, 41

Foramen lacerium

foramen, see

70

Gular, scutes

Page.

28, 37-^W, 44, 81, 102, 103, 105

33

M.

52, 54, 56, 57, 59, 77, 78, 79, 83, 105, 107

Intercentrum
45, 46, 63
Intel-medium
70, 71, 72, 73, 74, 109
Ischium.. 55, 57, 77, 78, 79, 80, 101, 105, 109, 111, 113

Malleous, external

MammahanMandible, see Jaw.

84, 8768, 84, 115

140
Manus

72, 74, 89, 90, 101, 103

Marsh, O. C, figures by

33,

44, 48, 52, 54, 56, 58, 59, 60, 63, 66,
69, 78-80, 82, 84, 88, 90-92, 94, 122
24, 106

fossil collections offossil remains described by. . .

1, 26,

27, 78, 79, 80, 82, 101,

102, 105, 106, 108-110

on Diracodonon Hoplitosaurus
on Nodosaurus
on Stegosaums

109

115
118
43, 45,55, 57, 61, 71, 88, 90, 91, 93, 94, 96, 125

work of1

MastodonNeural arch
Neiual canalbrachial enlargement
50
Neural cavity, see Sacral cavity.
Neural processes
51, 56, 113, 117
Neural spines
49-52, 54, 56-59, 94
Neurapophyses
48
New Haven, Conn., fossil collection shipped
106

toNodosaurus
Nopcsa, F. Baronon Polacanthus
on Stegosaurus
Notch, intercondylar

'.

118

47

118-12152, 64, 80-82, 96

82, 11781

0.

27, 33, 34, 44, 105, 108, 109

Maxillary
Medulla oblongata
Metacarpals.

43

Occipital condyle

71, 72, 73-75, 77, 105

Occipital segment

72-75

Metacarpus
Metatarsals

87, 88, 89, 90, 101, 103

Metatarsus

87-89

stone matrix

Colorado,fossilfossilOmosaurus-

122

Opisthotic

103

Optic lobes
Orbitosphenoid

lentus Marshflexorgluteal27, 29, 32

43
27, 30, 31, 43
27, 28, 33, 41, 102, 105

Orbits482

Ossicles84

Osteology of Stegosaurus

117

Owen, Richard, on Iguanodon

25

Muscles, caudo-femoral

102

40-43

30, 55, 80, 87, 88, 102
Omithopoda
82
Omithopodidae
81, 117
Osbom, H. F., on Diplodocus

4

agilis Marsli

102

hastiger, Owen

Openings in the skull, external

remains

103, 105, 109, 111

Morosaurus sp

80, 101, 102

armatus Owen

remains foundnearformation

28

45,46,47
32

Olfactory lobes

25

Montana, Fergus County,
found in88, 29, 45, 46, 125

Odontoid

Merrill, George P., on examination of sand-Morrison,49, 50, 57, 78, 102, 103, 117

46-50, 56, 59, 101, 103, 117

91, 99, 103, 105, 115, 118, 124, 126

26-10081

on Scelidosaurus

124

N.
Nails

70, 125

Nares, anterior

41, 105

posterior

36, 41

Paraoccipital

Narial orifice

33,34

Parapophyses

27, 31, 32, 33, 34, 41, 102, 105

NasalsNatrona County, see Wyoming.

27, 34, 36

Palatine-

27, 29, 30, 31, 32, 35,40, 105

Parietal

Nerves, facial
glossopharyngeal

42

Peduncle, iechiac
pubic
Pelvic arch

42

Pelvisoculomotor

43

Neck

63, 91, 96, 98, 99, 107, 109, 123-125

optic

43

Pes
Phalanges
Phalanx

pneumogastric42

Pisces56

Pisiform

31, 43

olfactory

sacral-27, 28, 29
48, 50, 54, 63

78, 7978,79,83
53, 5677, 79, 99, 103, 107, 125
86, £0, 101, 103

70, 74, 75-77, 87, 88, 89, 90, 105, 125

73-77, 89

4,25
70, 71, 72, 73, 74, 109

trigemnial

42

Pituitary body

43

vagus
Nervous system
Neuracentra

42

Plates, caudal

93-95,115,124

57

dermal45, 4651, 97-103, 105-107, 109,

114, 115, 119, 120, 122-124, 126

INDEX.

141
Page.

Plates, dorsal

52, 98-93, 115

measurements ofmorphology ofnuchalPleurocoeluB nanus MarshPolacanthus

Reed, W. H., material loaned

100
100
93, 1103, 4

Restorations of Stegosaurus

54, 55,57,

101, 114, 116, 118-120, 122

foxi Hulke

123-126

Ribs

30

Postemporal bar

1

work of63,64,78,98,105,107,

108, 111, 113, 114, 117, 118

121

caudal40

caudo-sacral

55,58,63108

Postfrontal

27, 2S, 31, 32, 35, 105

Postorbital

27, 30, 31, 33, 33, 34, 40, 41

dorsal52, 63, 64, 102

78, W, 80, 101

sacral52, 54-56, 63, 78

Postpubia
Postsupraorbital

cervical45, 47, 63, 102, 105

27, 32, 33

sternalPrearticular

27, 37, 38, 39

Riggs, E. S

54

Predentary
Predentata
Predentate

27, 37, 38, 105

Roberts, G. E., restoration by123

Prefrontal

27, 32, 33, 105

65

39
S.

66

Premaxillary27, 33, 34, 38, 41, 105

Presacrals

45, 49, 50, 52, 54, 63, 105

Presphcnoid

27, 30Presupraorbital

Sacro-caudal

25

52, 101, 117

55, 56, 59. 64, 77

Sacrals

52-54, 105, 108

cavity27, 32, 33, 41

Probaena sculpta Hay
Process, acromlan

53

Sauropod
Sauropoda

56,57,113

Sacrum45,
49, 51, 53, 57, 58, 62, 64, 78, 80, 97,

67

capitular

63, 64

olecranon

68, 69, 103, 125

spinous52, 59, 113

transverse

51, 52, 55, 57-59, 64, 78, 112, 113

tubercular

63

Prootic

101, 103. 105, 108, 111, 113, 122, 124

Sanford, E. J.

27, 30, 35, 36, 41

Pubis

55, 77, 78, 79, 80, 105, 111

122
66, 67, 105, 109, 114, 115

101, 114
33, 101. 118, 124

harrisoni Owen

88

Sclerotic plates

41

Scutes91, 100, 118-121

Sesamoid
Shoulder girdle

Q.

Quadrate
Quadratojugal
Quarry No. 1
fauna of27, 29, 34, 35, 36, 39, 40

history of

27, 34, 35, 40

105, 1062,

location ofplan of work
Quarry No. 13
fauna of

Skin
Skulls

27
36

24

26

2

5-24

SmilUe, T. W., photogi'apha by
Smit, T., restorations bySouth Dakota, fossil specimens found in.
Spines, caudal
dermaltubercular
Splenial

Radiale70, 71, 73, 74, 105

Radius69, 70, 71, 74. 105, 109, 110

Ramus mandibular, see Jaw.
Reed, W. H., fossil remains collected by.

.

.

26,

111. 113

remains discovered by.

2

.

.

114
115
91, 93,

107-112, 114, 119, 121-124

3,4

R.

2
123

94, 95, 96, 99, 101, 103, 105,

3, 109plan of work91, 92, 95, 97-99, 120

26-44, 63, 101-103, 105, 106, 109, 125

measurements

4location of83, 90, 103

summary of materials

2, 65, 93

list of fossil remains collected

66

Skeleton, mounted

24

25

history of

89, 90list of known elements

25

fossilranch of

Scelldosaurus

27, 29, 30, 33, 33. 42

Pterygoid,

ScapulaSceUdosauridae

Squamosal
Stegopelta

9227, 37, 38, 39
27, 29, 32, 35, 40

100, 118

Stegosauri*.

1, 101, 102, 110

Stegosauriau

52, 65, 81, 91, 99, 103, 116, 124, 125

Stegosauridae

83, 86, 101

Stegosauridea

102, 103

142
Stegosaurus

1, 2,

Toes

70, 87, 88, 90

26-28, 30-33, 36, 37, 39^1, 43^6, 49,

Tortoise

52,56-58, 60-72, 76-91,96-99,101-103,

Trachodon

105,106,108,109,113-118, 122-124, 126

annectens
Transpalatine

affinis Marsh

101, 102, 104

armatus Marsh

90

25,

Triceratops

26, 31, 32, 40, 55, 101-104(Omosaurus) armatus (Owen) . .
104

Trochanter

discursus (Cope)

102, 104

duplex Marsh

1, 28, 32, 45, 52, 61, 63, 66, 84, 125

65, 66, 88

36
28, 30, 39, 42, 44, 51, 52,

69, 78, 79, 81, 82, 84, 114, 121, 122, 125

82, 83fourth82, 103, 116, 117

55, 102-104

great

81, 82, 113, 116, 117

durobrivensis Hulke

104

lesser

81, 82, 103, 108, 113, 116(Omosaurus) hastiger (Owen) . .
104
longispinus Gilmore
81,
83, 95, 104, 111-113
marshi (Lucas)
102, 104, 114-115
priscus Nopcsa
47, 80-82, 104

major

81, 117third

82, 101

Trochlea

68, 82, 115

TroodonTubercle

64, 120

seeleyanus (Cope)

Tuberosity

89

greater.

68

102, 104

stenops

1, 2, 4,25-37", 31-33, 35-37, 40, 43-45, 50,

44

68

lesser53-57, 59, 61, 63, 67, 68, 70, 74, 75,

U.

78, 79, 81-85, 93,95-97,100,102,104,

106, 109, 112, 113, 122. 123, 125- 126.

description of type-specimen.

104-

Ulna

69, 70-72, 74, 103, 105, 109, 110, 125

106

UlnareUnguals
University of Wyoming,
belonging totheory of fossilization

107, 108

Utterback, W. H., work ofsulcatus Marsh

4, 68-70,

.

.

109
history of type-specimen

106

position of the skeleton

111

75-77, 88, 89, 90
fossilspecimens
81, 111-113, 123

24

V.

73, 74, 76, 92, 95, 96, 102, 104, 108, 109^

ungulatus Marsh70, 71, 72, 74, 109

41

Vacuities, palatiae

28

supraorbital

4, 45, 50, 53-

60, 63, 66-69, 79-84, 88, 89, 91, 92, 94-

Valentine, Mont., fossil remains found near.

96, 101-104, 108-110, 113, 116, 122, 125

Vertebrae

Sternal bones

109, 110

Supinator ridge

68, 115

Supraoccipital27, 29, 30, 31, 32, 41

Supraorbital

28, 33, 41, 103

Surangular27, 37, 38, 39

Suture coraco-scapular

67

51-53, 55-59,
63, 64, 91, 93, 96, 98-103, 105-107, 111, 114

65, 66, 82

Sulci

caudal54,57,58-61,62,
93, 96, 99, 103, 105, 106, 109, 111-114, 117

47^9, 50, 91, 102, 124, 125

cervicaldorsal45,
48, 49-^2, 55, 63, 103, 113-115, 117, 124
45, 52, 53-56, 63'dorso-sacral

lumbar

45, 100
53, 55, 56, 105, 107

sacralTail

57-59, 61, 62, 91, 94-96, 99,
103, 106, 108, 111, 113, 117, 118, 122, 123-125

Tarsals

83, 101

TarsusTeeth
Theropoda

Th3rrohyals
Tibia45-61, 52, 54, 59

formula86

neglectiis Gilmore

ThroatVertebral column

45

Vomer

27, 34, 36

W.

34, 37, 44, 45, 101-103, 105, 109, 126

Thescelosaurus

77

Wait, G. L., fossil remains collected by .

66

Wealden formation

88
103, 115, 118«

40
84, 85-88, 101, 103, 105, 107, 109

122

Weber, Rudolph, drawings by
Wieland, G. R., on dinosaurian armor
on Hierosaurus
Williston, S. W., work of

.

.

.

122

114
2
121
118, 122

24

INDEX.

143

Page.

Wyoming, Albany County,

fossilremains

discovered in

2, 109Big Horn Coimty, fossil remains discovered in
Carbon County, fossil remains discovered inConverse County, fossil remains collected in

Natrona County,
covered inremains

dis-

121, 124
54, 55, 57, 108122
Zittel, Karl, on Diracodon laticeps

122

on Stegosaurus
Zj'gapophyses

122
fossilYale University
Yoke, sacricostalmoZygoaphene

109
102, 103

46, 49, 52, 57-60, 99

52