! 

I ENGINEER DEPARTMENT. U. S ARMY. 

- . --=---=-----

HEOIJR,\PIIICAL I:XPLORATJONR t\NO 8URH:Y8 WEST 0~1 ~'Ill~ 100I'Il n!ERIDIAN. 

FIRST Lmm·. 0IW. 1\l. WHEELRH, 

COHPR OF Ja\(~JXEt?.'J.S, IN CO.\HGE. 

I SYSTE~IATIC CATALOGUE 

OF 

VERTEBRATA 

01' '1'111<] 

I 

I COLLECTED IN lt374. 

E'. D. COPE. A. M., 

PALEONTOLOGIST. 

WAS HING'fON: 

GIIVJ;;l~Nl\'lEN'I' PRINTING OFFLCE. 

April17, 1875. 
LIBRARY OF 

W. E. CRANE 

No. 

I . 

rfitlf de ~omfltmen,:B of 

!Jl,tat. ~e Jlt /f%a/ee, 

Y/c,yzd oj r&;tt4zeeu. 

oa' !/. J?ftmJ' 
) 

ENGINEER DEPARTMENT, U. S ARMY. 

· GEOGRAPIIICAL EXPLOR:\TIO~ S HD SURVEYS 1VEST OF 'filE 1 OOTll J!ERIDIAN. 

FIRST LIEUT. G lcO. M. WUE ELlm, 

COUPS OF ENGL'\EERS, IN CHARGE. 

SYSTE~IATIC CATALOGUE 

01' 

VERTEBRATA 

OF TJIE 

EOCENE OF NEW MEXICO. 

COLLECTED IN 1874. 

E. D. COPE, A. M., 

PALEONTOLOGIST. 

WASHINGTON: 

GOVERNMENT PRINTING OFFICE, 

Apri117, 1875. 

OFFICE OF THE CHIEF OF ENGINEERS, 

lYashington, D. C., JJ1cwch 8, 1875. 

SIR: Lieut. George l\1. Wheeler has sent to this Ofiice l'eport of Prof. 

E. D. Cope on the vertebrata from the Eocene of New Mexico, obtained 

oy the geographical survey under his charge, during the field-season of 

1874. 

I have respectfully to recommend that it be printed at the Government Printing-Office, and tllat fifteen hundred copies ue furnished on 

requisition from this Office. 

Very respectfully, :your obedient servant, 

A. A. HUMPHREYS, 

Brigadier-General and Chief of Eng·ineers. 

Ron. W. W. BELKNAP, 

Secretary of War . 

.Approved: By order of the Secretary of War. 

"'"AR DEPARTMENT, March 97 1875. 

H. T. CROSBY, 

Chief Clerk. 

UNITED STA'l'ES ENGINEER-OFFICE, 

GEOGRAPHICAL EXPLORATIONS AND SURVEYS 

vVEST OF THE ONE HUNDREDTH MERIDIAN, 

Washington, D. 0., ~JJtarch 5, 1875. 

GENERAL: I have the honor to forward herewith a systematic catalogue of vertebrata from the Eocene of New Mexico, with description of 

new species, prepared by Prof. E. D. Cope, A. M., paleontologist to the 

expedition of 187 4, and to request that, in order to establish priority of 

discovery, it be printed and bound at the Government Printing-Office, 

and that fifteen hundred copies be furnished for the use of this Office. 

Very respectfully, your obedient servant, 

GEoRGE M. vVHEELER. 

Brig. Gen. A. A. Hul\IPHREYS, 

Lieutenant of Engineers, in Clzarge. 

Chief of Engineers, U.S. A. 

SYSTE~IATIC CATALOGUE OF THE VERTEBRATA OF THE EOCE~E 

OF NEW MEXICO. 

BY E. D. COPE, A. :L\I, 

PHILADELPHIA, FebTuary 19, 1875. 

SIR: The present essay completes the determination of the species of 

Yertebrata obtained by the geographical survey under your charge in 

the Eocene formation of New J\fexieo during the field-season of 187 4. 

The descriptions whicll have already appeared in your report to the Chief 

of Engineers, as published in the annual report of the latter for 1874, 

are not now repeated. The total number of mammalia is forty-seven 

species, of which the present report introduces twenty-four for the first 

time. 

I remain yours, sincerely, 

Lieut. G. ~r. WHEELER, 

Vorps of Engineers. 

MAMMALIA. 

CARNIVORA. 

E. D. COPE, 

Paleontologist. 

The genera of this order which can be compared, differ as follows in 

points of dentition: 

A. Carnassials without opposite inner tubercle. 

Carnassials with two cusps and without heel. Hyccnodon. 

Carnassials with straight heel and anterior cone. J.l1esonyx. 

Carnassials with three 01' more tubercles in one series. Ambloctonus. 

A.A. Carnassials with inner cone or tubercle opposite the outer; no 

tubercular molar: 

Two tubercular carnassials. 

Three tubercular carnassials. 

A.AA. Tubercular teeth behind tubercular carnassials. 

Oxycrna. 

P1·ototorwus 

One tubercular, and one tubercular carnassial; no incisors. Didy 

1nict-is. 

Two tu berculars. Oynodon. 

The series of dental types which precede the complex structures. 

of teeth, presented by the most specialized divisions of the hoofed 

mammalia, haYe been pointed out by the writer in au essay on the Origin and Homologies of the Types of Dentition of the :Mammalia Educabilia*. From this discussion the analysis of the most specialized sectorial tooth of the carnivora, as seen in the Felidm, was omitted. As 

light has been thrown on the subject by later re~earches, a note of the 

,.Journal of the Academy of Natural Sciences of Philadelphia. 1874. 
6 

conclusions will be made here, chiefly with reference to the dentition of 

the lower jaw. 

In the above essay I regarded the simple four-lobed or quadrituberculate molar of the hypothetical Bnnother·iu1n as the starting-point of 

all more specialized forms of crested teeth. The second lower molars of 

the peccaries (Dicotyles) represent such a type. It was also pointed out 

that additional tubercles may be added to this or to a still simpler form 

by the development of basal cingula. 

The genus Hyopsodus presents a modified form of quadrituberculate 

molar. In the genera Pantolestes and Ant-iacodon we observe that the 

tubercles are similar, excepting that the anterior inner is double or 

slightly ~ifid. In Pelycod~ts, (whose systematic position is uncertain,) 

the two apices of this tubercle are separated more widel.v from each 

other, so as to constitute two cusps. These are connected with the anterior-outer cusp by acute ridges, which thus form two sides of a triangular area. The anterior ridge is evidently a developed cingulum. 

The tubercular molar of some Viverridce, and among the extinct forms 

eRpecially the Didymictis proten1ts, Cope, present a similar structure to 

that just described. This furnishes a re;tdy explanation of the tooth 

immediately in advance, which is the primitive form of sectorial tooth 

characteristic of that type of Uarnivora. The three anterior tubercles 

are largely developed, standing at opposite angles of a triangular space; 

the outer and anterior cusps are the most elevated, and the ridge which 

connects them is now a cutting blade. The posterior portion of the tooth 

does not share in this elevation, and its two tubercles are iu some genera 

obsolete, and in others replaced by an elevation of one margin, which 

leans obliquely toward the middle of the crown. In Mesonyx this is rPpresented by a median longitudinal crest. If the two tubercles of the 

posterior part of this tooth (which may be termed a tubercular sectorial) 

are elevated and acute, we have the molar of many recent and extinct Insectivora; if the same portion (now called a heel) is much reduced, we have 

the type of Oxycena andStypolophus. In the Canidce the three anterior tubercles are much less elevate<l than in the genera above named; the external is much the larger, and the anterior removed farther forward so as to 

give the blade a greater antero-posterior extent. The heel is large and 

without prominent tubercles. In the1llustelidcc the inner of the two median 

cusps is often reduced to a rudiment, or is entirel~y wanting, and the heel is 

large. Tile lower sectorial of the Hycen-idw has no inner tubercle, and the 

heel is much reduced. In some of the saber-toothed tigers the heel remains as a mere rudiment, while in the true cats it has entir~ly disappeared, and the carnassial tooth remains perfected by subtraction of 

parts, as a blade connecting two subequal cusps. TheJI.yccnodontidw, as is 

known, possess three carnassial teeth without inner tubercles. The history of this form is as yet uncertain, as it was eddently not derived 

from contemporary forms of the Eocene with tubercular sectorials. 

'l'he development of the carnassial dentition has thus been accomplished, first, by an addition of an anterior cusp, and subsequently by 

the subtraction of the inner and posterior cusps, so that of the original 

four of the quadrituberculate molar but a single one, i. e., the anterior 

external, remains. The same process may be observed in the successional modifications of the entire dentition of the jaws. The Eocene 

forms of carnivora frequently display more numerous sectorial teeth 

(such as they are) than any of the existing families. The important 

change, which is clearly indicated, is the progressive extinction of the 

genera with numerous sectorial teeth, accompanying the increasing 

specialization of the sectorial tooth in the genera which remain. In 
7 

other words, the numerous types of digitigrade carnivora which have 

survived, are those developing but one sectorial tooth, (whose earliest 

representative is Didyrnictis.) The increased perfection of the sectorial 

has been· associated with a reduction in the number of other molars, 

first, posterior, then anterior to it, which reduction bas been accompanied by an increased relative size of the sectorial. By this process concentration of the carnassial function bas been gained, and increased 

robustness of the jaws, by progressive shortening. The slender form of 

the rami of the Eocene genera and Hywnodon are much less efficient 

in functional use than the stout jaws of existing Jlfrustelidm, Hywnidcc, 

aud Felidcc. 

A second point in the history of the Eocene carnivora remains to be 

considered. In all of the genera which I have had the opportunity of 

examining, excepting 1lfesonyx, namely, A1nbloctonus, Oxymna, Prototomus, D'iclymictis, the tibio-astragalar articulation is of a primitive character. The astragalus is flat, and the applied surfaces are nearly a 

plane, and without the pulley-shaped character seen in existing carnivora; as dogs, cats, and in a less degre~ in the bears and in other 

mammalia with specialized extremities, as Perissodactyla, Artiodactyla, etc. The simplicity of structure resembles, on the other band, 

that found in the opossum and various Insectivora, Rodentia, and 

Quadntmana, and in the Proboscid-ict, most of which have the generalized type of feet. The structure indicates that the carnivorous genera 

named were plantigrade-a conclusion which is in conformity with the 

belief already expressed that the mammalia of the Eocene exhibit 

much less marked ordinal distinction than do those of the Miocene or 

the recent periods. It is indeed questionable whether some of the genera 

here included in the carnivora are not gigantic Insectivora, since the 

tibio-tarsal articulation in many, the separation of the scaphoid and 

lunar bones in Synoplotherium, the form of the molars, and the absence 

of incisor teeth in some are all characteristic of the latter rather than 

the former order. 

AMBLOCTONUS, Cope. 

The fossil remains which illustrate this genus include the greater part 

of the dentition of one side of the cranium and that of the posterior 

part of the mandible, with a number of bones of the limbs; the teeth are 

somewhat worn, but not so much so as to prevent determination. The 

superior molars preserved are three in number; four extend posteriorly 

from below the orifice of the foramen infraorbitale exterius. The 

crowns are longitudinal, and consist of a three-lobed extm·ior blade 

and an inner depressed tubercle. The last molar is longitudinal and 

not transverse, as in Oxycena. The superior canine is large and is preceded, with a short intervening diastema, by a very large exterior incisor. 

The last inferior molar consists of two cusps and a rudimental heel. Tlw 

cusps form a short carnassial blade. Their number cannot be determined 

on the penultimate molar, but the1·e is a well-developed heel, and the 

anterior part of the crown is wide. The molar which precedes has three 

principal cusps, the two anterior forming together a blade; in the t~'lJe 

species there are acceBsary tubercles adjacent to the posterior cusp. 

The trochlear surface of the tibia is olJlique and nearly uninterrupted, 

much as in Oxycena, and without the grooves for an hour-glass shaped 

astragalus, as in .1tfesonyx. 

This genus probably belongs to the Hymnollont-idre, and resembles Hycenodon in the structur? ·. ts sn1)erior molars. It differs in the inferior 
8 

molars, especially in the tubercular heel of the antepenultimate and 

penultimate, aud probably in the arrangement of cusps on the interior 

part of the latter. 

A::nnLOCTONUS SINOSUS, Cope, (sp. nov.) 

Two incomplete skeletons represent this species in the collections of 

the survey. The best preserved includes the right maxillary bone, 

with crowns and roots of the last four molars. The first of these is 

wider behind than before, the posterior root being double. The next 

has a triangular crown, with the exterior and anterior borders at right 

angles to each other, and of subequal le11gtbs. The fourth tooth is 

not quite so wide, but is a bout as long as the one just described, has three 

lobes of the outer summit, and a convex anterior border. The interior 

heel of the :first molar is constricted at a point of its border, mdicating 

an additional internal cusp, probably basal. The foramen infraorbitale is remarkably large. Owing to the state of the specimen, the 

number of premolars cannot be ascertained. The canine is worn almost to the alveolar border in a vertical truncation. The diameter of 

the alveolus for the third or outer incisor is out little less than that of 

the canine. 

The characters of the three last inferior molars may be partially determined from the two individuals. The last molar is smaller, in tlle 

specimen already partially deseribPd, tllau the two ·which precede it, 

wb.ich are subequal. It b.as a very short heel, with a cutting edge on the 

outer side. The remainder of the crown is subtriangular in section at 

the base, supporting a posterior and an anterior tubercle, which are 

connected on their iuner sides by a cutting edge. There is a cingulum 

on the external base, continuous with the border of the heel. The antepenultimate molar has three cusps, of which the anterior and posterior have subequal bases. The anterior tnrns to the inner side of the 

tooth, the median stands on the inner side, while the posterior is median. It has an accessary tubercle on each side of it, that of the inner 

side much the more elevated, and coml>ining witb. the median to form 

an incunTed grinding surface, on attrition. 

The distal part of the calcaneum is rather elongate and compressed. 

This species of carnivore is of robust character, and about the size of 

the jaguar. 

Measurements. llf. 

IJength of bases oflast four superior molars, (No. 1) .........••....•.••••• _... • • . . • 07 J 0 

Length of crown of antepenultimate molar. .•.........•.......... _ •.. _ •••...•• _. . 0 I 75 

'\'idth of crown of antepenultimate molar ......••...•.................•••.••••.. 0170 

Length of crown of last molar ...• -. . . • • • • • • • • • • • • . . . . . . . . . . . . • • . . • • . • . • • • • . . . • • 0180 

·width of crown of last molar .....••••• ---· .•..•.•••....•............•••.•••.•• 0160 

Length of last three inferior molars ....•••••......•.••....•.....•..... _ •.•.. ~.. . 0410 

Length of crown of last inferior molar .....•.••.....•.......••....• _ •.•.•..• _. __ . 0120 

·width of crown of last inferior molar. .........•.•............•....... ___ ••... _ . U080 

L<>ngth of crown of antepenultimate molar .•....••.•...••..........• _ •••.••• _ •.. 0140 

W"idth of c-rown of antepenultimate molar ••......• , .......•....•. _. _ ••. __ . . • • • • • . 011 0 

Diameter of superior canine ...•.......••................•••......•••.••••••.... 0170 

Length of last three inferior molars of specimen, (No. 2) ..........•.••..•• __ ••• _. . 0490 

Length of antepenultimate molar of specimen, (No.2) ........ _ ..•••...•••..•••••. 0150 

Depth of ramus of jaw at penultimate molar ..................•........••••• __ •• . 0420 

Diameter of shaft of femur of (No. 1,) below middle...... . • . . . . . . . • • . . . • • . . • • . . . 0:!40 

Diameter of head of f; mur .••. -... -••... -.-..••••....••....••....••...•• _. • • • • • 0270 

Diameter of shaft of tibia, (least).-.-•......•.•....•.......•.........•..•• _ •• _.. . 0190 

Diameter of distal end of tibia measured obliquely ........... _ .•.. _ ..••...••. __ •• • 0350 

Diameter of calcaneum, vertical. ••••...• _ .••..... ___ ..•.•••..• _ •.. _ .•.•..•. _... , 0260 

Diameter of calcaneum, transverse.... • • . . • • • . . • • . . . . . . . • . . • . . • • • • • . . . • • . • • . • . . . • 0130 
9 

As compared with the S.IJnoplotherittm lanius, Cope, to wllich this species is probably allied, all the teeth are wider and more robust, excepting the canines. Although the disposit.ion of the tubercles of the 

lower molars in Synoplotheriunt is unknown, the narrow form of their 

bases renders it probable that the structure is rather as in Hyccnodon 

than as in Arnbloctonus, especially in regard to the antepenultimate, 

which is so exceptionally tubercular in the present animal. 

OXY .. lENA, Cope. 

Heport on Vertebrate fossils~ obtained by the vVheeler Expeditionjn New :~\Iexico, 1874, p. 11, (extracted from report of Lieuteuant Wheeler to 

Chief of Engineers.) 

This genus resembles Pterodon, as described flnd figured by GerTais, 

in the dentition of the maxillary bone; but the teeth of lower jaw are 

totally distinct in character, approaching more nearly those of the Pcdcconictis of Dr. Blain ville. .11""1rom the latter, it differs, among other points, 

in the character of the antepenultimate lower molar, which in Oxymna 

is characterized by the presence of a median blade, but in Palmonictis 

by a heel supporting (in the typical species) two tubercles. 

The Oxywnas were the most abundant of the Eocene carnhTora, estimating them by the relative frequency of occurrence of their remains. 

There were at least three specit~s, which ranged from the size of a terrierdog to that of a jaguar. 'rhey are of a robust structure, and resemble 

Synoplotheri1.un in the anterior production of their canine teeth, which 

are so closely approximated as to exclude tile incisors altogetlwr. 

Specimens obtained include the dentition of both jaws and bones of the 

skeleton. The phalanges have the same flattened form seen in the fiatclawed genera discovered in vVyoming. 

OxY .LENA 1\-IOl~SITANS, Cope, l. c., p. 12. 

OXY.LENA LUPINA, Cope, l. c., p. 11. 

OXY.LENA FORCIP.A1'A, Cope, l. c., p. 12. 

PROTOTOlVIUS, (Cope.) 

Loco citato, p. 13. 

Having obtained more perfect specimens of the lower jaws of this 

genus, I find that I must correct the diagnosis given as above cited by 

the ascription of three tubercular sectorial molars to the inferior dentition, in correspondence with the number there stated to characterize the 

maxillary series of teeth. This is one more than exists in O.:cycena. Two 

such teeth are also ascribed to PatriojeUs, Leidy, and Viverravus and 

LliTnnocy01t, .Marsh, by their describers. No existing genus of Carnivora 

possesses a similar dentition, but it is presented on a diminutive scale 

by some Insectivora. 

PROTOTO~IUS VIVERRINUS, Cope, l. c., p. 13. 

PRO'l'OTO:MUS SECUNDARIUS, Cope, sp. nov. 

Represented by an incomplete mandibular ramus, which supports fonr 

m.olars. The penultimate has a well-developed heel, whose outer border 

is elevated and acute, and turned in so as to approach the middle of the 

crmrn. The fourth molar from behind has a heel with a symmetrically 

median cutting-blade; enamel smooth. The ramus indicates a species 

the size of an opossum, and intermediate between the P. viverrinus and 

t1le P. multicuspis. ' 
10 

Measurements. 

M. 

Length of crowns of two anterior trne molars .••••..•.••..•..•..•••.••••••••••••. 0150 

Length of penultimate molar...... . . • • . . . . • • • . . • • . • . . . . • . . . • . • • . . . • • • . . . . . . . . . . 0075 

Width of penultimate molar...... . . . • . . . • • • • . . • . • • • . . . • • . . . • • . . . • • • • . • • • . . . • • . . 0033 

Depth of ramus mandibuli at penultimate molar ..••••..••.•...••...•••.....••... 0125 

'l'hickness of ramus mandi buli at penultimate molar...... . . . . . . . . . . • . . • . . . . . • • . . . OOfiO 

Length of crown of third premolar . . . . . • • • .. . . . . • • . . . . • • . . . .. . . . . . • • • • . . . . • • • . , 0080 

PROTOTOl\f"CS MULTICUSPIS, Cope, sp. nov. 

Established on a series of sllperior molars, which accord so closely 

with two series of inferior molars as to leave no room for doubt that 

they pertain to the same species. One of the latter specimens includes 

the greater part of the right ramus of the mandible; the other the principal part of both rami. 

The superior molars are twi~e the size of those of P. vi,verrinus, and 

have much the same structure. The last or transverse molar has less 

extent and is inserted by one root only; the penultimate molar is wider 

than long; the antepenultimate longer than wide. There is a short 

blade in front of the double cone in the penultimate, but none in front 

of the corresponding cones in the two molars which precede. The cingulum of the inner base is very obscure. 

In the true inferior molars the three anterior cusps are much elevated 

above the heel. The latter is quite elongate on all of tllese teetll, and 

forms a cutting-blade on the last premolar aud anterior two molars; the 

second aud third premolars support a low trenchant posterior heel. ~o 

external cingulum; enamel smooth; rami of the mandible slender. 

,Measurements. 

Length of posterior four molars .............................................. . 

Length of penultimate molar ................................................ . Width of penultimate molar ................................................. . 

Width of antepenultimate molar ............................................. . Width of first molar .•.••...••••....••..•..........•.........•••....••.•..... 

~r:;:~o~- tr~fi~s~~~~a·r- :::: :::: :::::: ::: :: : ::: : ~ ~ :::: ~::: ~: ::: : :: : ::: :: :::::: 

Length of last six inferior molars ............................ _ ....... ~ ....... . Length of three true molars ....•..•.•.....••.•...•..... _ ..••••• _ •..•....••••• 

Length of last true molar ................................................... . Elevation of true molar .......•...••••............•..•.•••••..••••.•....•••. _ 

Length of seeond true molar .••••....•........•••......•..•••................ Elevation of third premolar ....... )~ __ .......... ___ .......................... . 

Depth of ramus at penultimate molar ........................................ .. 

About the size of the red fox. 

PROTOTOMUS STRENUUS, Cope, sp. nov. 

u. 

. 0:270 

. 0070 

. 0090 

. 0070 

. 0060 

. 0075 

. 0050 

. 0450 

. 0:!35 

. oouo 

.vo7o 

. 0075 

. 00:35 

. 0015 

Both mandibular rami, with representatives of all the teeth except 

the first premolar, form the basis of our knowledge of this carnivore. 

The characteristic feature is the great robustness of the jaw as compared with the species last described as well as the somewhat larger 

size. The third premolar has a cutting edge and basal tubercle in 

front, which are wanting in the P. multicuspis. The third and fourth 

premolars are stout teeth, composed of a large cusp of lenticular section 

and a trenchant heel. The fourth is 'thich:ened on the inner side, but 

the apex is broken away. The penultimate molar is larger than the last, 

and its heel, with that of the one preceding, is well developed. The 

first true molar is smaller than the second, and its cuspidate portion 

smaller than the corresponding part of the last molar The inferior 

canine is stout at the base and acute at the apex. The external face 
11 

exhibits two shallow longitudinal grooves separateu by a low convex 

rib. Enamel of all tlw teeth smooth. 

Measurements. 

M. 

Length of last five molars ..• - •..• ---- ••....•••.••..•.• --•. ----. . . . • • . • • . • . . . . . 0:375 

Length of last pre1nolar ..•••.....•. - ...•• -•.........•....••••.......• -.. . . . . . . 0080 

Length of first true molar .. -••.•••••.•....•......... -.. . . • • . . • . . . . . . . . • . . . . . . • OOi:lO 

Length of second true molar ..•• -. . . • . . . . . . . . . . . . . • • • . . . • . . . . . . . . . . . • • . . . . . . . . 0080 

Width of second true molar .•..•...•.••.•............•...•••..•••......•...... 0065 

Length of last true molar . . . • • • . . . . . . . . . • • . . . . . . . . • . • . . . . . . . . . . . . . • • . . . . . . . . • . 0075 

Depth ofjawat lasttruemolar .........................••••..•............... 0210 

Depth of jaw at second premolar. ..•................••••...••.....•.•.••...... 0175 

Thickness of jaw at second premolar .• -••.... -.. . . . . . . . • . . . . • • • . . . . . • . . . . . . . . • . OOtiO 

Length of inferior canine .....•......••..•....•.•..•....•• -- ... -.•.•.• -.. . . . . . 01:t3 

Long diameter of inferior canine at base ..•....•• --•...•• -.•...... -..••...•• -.. • 0065 

Tile thickness of the mandibular bones is twice as great as that of the 

species last described. 

Other species formerly referred to this genus are now placed in ApheUscus and Pelycodus respectively. 

DIDYMICTIS, Cope. 

Inferior molars, six, consisting of four premolars and two true molars. 

True molars, a posterior tubercular and an anterior tubercular sectorial, ~·e., with three elevated cusps and a post,erior heel; premolars with a lobe 

behind the principal cusp. The canine teeth are directed forward and 

are very close together, so that it is doubtful whether there were any 

incisors. An ungueal phalange of the typical species is strongly compressed. 

'rhe resemblance of this genus to the existing Viverra in dental characters is so great tllat the only distinctive feature appears to be the 

deficiency of the full number of incisors. I formerly referred the typespecies to Limnoc.!Jon, but that genus i~ stated to possess "two tubercular molars," which are not applicable to the present form, whether true 

tuberculars or tubercular sectorials is intended by that expression. 

DlDYMIC'l'IS PROTENUS, Cope. 

Limnocyon prot£nus, Cope, Report on Vertebrate Fossils of New Mexico, 1874, p. 15. 

Not rare in the Eocene of New }fexico. "I 

PACHYAENA, Cope. 

Loc. cit., 1874, p. 13. 

P ACHY .lENA. OSSIFRA.G.A., Cope, l. c., p. 13. 

DIACODO~, Cope. 

Genus Novwn.-Four true inferior molars, which are composed of two 

portions; the anterior much elevated, and supporting two opposite acute 

cusps; and a posterior much depressed, bounded by some low tubercles 

postedorly. Superior premolar compressed, without basal tubercles. 

This form is probably a trne insectivore. It differs from many genera 

in the number of its true molars, adding one to tlle usual number. It 

differR from most of them also in the absence of the anterior cusp of 

the molars; among others, from Herpetotherium, Cope; of the l\1iocene, 

wllere tile number of molars is tile same. Of the numerous genera of 
12 

Insectivora reported from the Eocene of Wyoming but few have been 

described, and among the latter I find none without the auterior cusps. 

DIA.CODON ALTICUSPIS, Cope, ~p. nov. 

Represented by a right mandibular ramus, which supports the last 

premolar and the true molars, with a superior premolar iucluded in an 

attached portion of matrix. 

The two elevated cusps of the anterior part of the crown are of equal 

height, and are separated by a pronounced notch. There is a narrow 

cingulum extending across their front. The heel supports two or three 

low cusps, of which the exterior sends an oblique ridge to the base of 

the inner of the anterior pair. No basal external nor internal cingulum; 

enamel smooth. The mandibular ramus is quite robust. 

Measurements. 

M:. 

Length of five posterior molars ..•.....••....•••..•....••.•.•.•••.•.••..••..•... 0125 

Length of three true molars .. -.•.•. -.. ___ ........••.....•••... -•...•. -.. . . . • . . .OOA5 

Length of penultimate molars ........•. _ .....•........•......... _. . . • . . . . . • • • . .0025 

'ViJth of penultimate molars ..........•..•...••.••••..••••.•••••...•.......•••. 0018 

Depth of ramus at penultimate molar ....••••..••••.•••••.•••••.•••••..••••.•.•. 0045 

The jaw is nearly twice the size of that of the common mole, (Sca,lops 

aquaticus.) 

DIACODON CELATUS, Cope, sp. nov. 

The smallest mammal of the Green River Eocene yet known is represented by left mandibular ramus, which I found exposed on tbe face of 

a precipice of saudstone, on a peak of the Bad Lands. It supports the 

last three molars, which have nearly the character of those of the species last descrilled. The last molar is less than the others in the present 

animal, but equal to them in the D. cdticuspis. The posterior part of 

the crown is deeply excavated, and supports on its outer angle a sharp 

cusp. The anterior cusps are twice as high. There is no external basal 

cingulum. Tile ramus is shallow, and the masseteric fossa is deeply 

excavated. 

Measurements. 

1\f. 

Length of ramus from antepenultimate molar to angle ...•...•..•••..•••...•••... 0100 

Length oflast three molars .. __ ... _ ••••.....••.•... -....•...... -. . . . . . . . . . . . . . . .0048 

Length of penultimate molar .............. , ...•.....••..•.•.....••. ----·· .•.•... 0015 

Elevation of penultimate molar anteriorly............. . . • • • . . . • • • . . . . • • . . . . . . • . . .0013 

Depth of ramus at antepenultimate molar- ...••••. -... . . . . . . . • • . . . • • • . .• • • . . . . . . .0018 

This species resembled some of our very small sorices in dimensions. 

GENERA INCERTJE SEDIS. 

Under this head are included, provisionally, a number of genera whose 

position cannot be determined uy the structure of the molar teeth alone. 

Some of them are qnadrumana, and others perissodactyla. Until their 

structure is sufficiently known, I distinguish them b.r peculiarities of 

dentition only, in the following table. The molars of the inferior series 

are aU bunodont, but the upper series is only certainly known to be such 

in Phena,cordes. In Hyopsodus and Orothe1·iwn, they are perissodact,yle 
13 

in t~rpe, the external cusps being flattened, and the internal more or less 

connected with them by intermediate tubercles or ridges. I include in 

the table some perissodactyle genera. 

A. The anterior inner tubercle of the inferior molars double. 

I. The three anterior cusps, embracing a triangular area. 

Last premolar "'.Vith internal cusp, four premolars; last inferior molar with heel . _ ....... . 

Last premolar like that anterior to it, (i. e., 

without internal cusp;) three premolars.-

(Leidy) .. _ ............... -.-- ... -..... -- .• 

II. Twin cusps closely united, posterior cusps present. 

Last premolar without internal cusp; premolars continuous ......... _ ............... . 

Last premolar with internal cusp; sectorial ... . Last premolar similar to the first molar.-

(Marsh) ....................... -... - ... - ~-. 

AA. The anterior inner tubercle of the true molars not 

divided. 

d. Last inferior molar without heel. 

Last premolar without inner tubercle ... dd. Last inferior molar with a heel. 

Last inferior molar with a longitudinal series of 

Pelycodus. 

Omomys. 

Pantolestes. 

Ant-icwodon. 

OrotheriU1n. 

Apheliscus. 

tubercles ...... _.................. . . . . . . . . Opistlwtonws. 

Three premolars; no diastemata.-(Leid,y). _.. .Microsyops. · 

Four premolars, the last with internal cusp; no 

diastemata ............................. _ . }"~our premolars, last witll internal cusp and 

posterior tubercle; first premolar isolated. _ .. 

PELYOODUS, Uope. 

Hyopsodus. 

Orohipp~ts. 

Genus nov·um.-The principal characters of this genus, as above defined, are derived from a right mandibular ramus supporting 1hTe molar 

teeth, which was accompanied by numerous bones of the skeleton. Other 

specimens support the last molars. The proper nomenclature of the 

teetll is uncertain. If there are three molars and four premolars, then 

the canine alveolus is much smaller than that of the external incisor. 

Assuming these numbers as correct, the anterior premolar has left only 

its roots close to the canine alyeolus. It is two-rooted. The ineisor precedes the canine nearly in contact, and is stout. The second premolar 

is a flat cone, with anterior and posterior cutting-edges. The third premolar has two strong median cusps, the outer the larger, and a short 

broad heel. The last premolar resembles the first molar. The molars 

are peculiar in the width behind as compared with that of the front of 

the crown. Three approximated cusps stand on the latter, while a marginal ridge incloses a wide basin-like area behind. This ridge rises into 

a cusp on the external posterior border, and sends an oblique ridge 

toward the anterior cusps. The last molar differs from the others in 

the presence of a posterior heel, and resembles the one which immediately precedes it in its basin-like crown. The genus resembles Omomys 

(Leidy) in many respects, but is obviousl.Y distinct from it. It approaches 

also Tmnitherimn, Cope, but is quite distinct in the two-rooted premolars, 

the complex third premolar, the enlarged outer incisor, etc. With that 

genus, it is doubtless to be referred to the Quadr-umana. 
14 

PELYconus JARRovn, Cope. 

Prototornus jarmvii. Report on Vert. Fossils of New Mexico, 187 4, p. 14. 

The remains of this species indicate its size to have been about 

that of the raccoon, and that its jaws were robust. The second premolar is broad at the base and has a posterior cingulum. The third 

premolar bas an anterior basal cusp, and a broad low heel supporting 

a small tubercle. Neither premolar possesses any lateral cingula. The 

three molars have a basal cingulum on the outer side only. In the 

fourth premolar the marginal posterior ridge is strong, except on the 

inner posterior angles, where it disappears. In the other molars it continues all around. The two inner interior cnsps are connected with the 

corresponding external one by concave ridges. Symphysis of the 

rami not co-ossified. 

Measurements. 

M. 

Length bases of seven molars.... . . • • • . .. .. .. .. . .. . • .. .. .. .. . • • • • . . • • • .. .. • • • • . 0:335 

Length bases of four premolars ............... __ . . .. • • • . • . • • . . . .. . . .. .. .. . . .. . . . 0160 

Length base of fourth premolar ....................... _ ................. _.. .. .. . 0050 

Width of crown of fourth premolar ............................................. 0040 

Length of crown oflast molar ................................................... 0060 

Width of crown of last molar ........ ------ .............. __ ..................... 0050 

The enamel of all the teeth is smooth. 

Three individuals obtained. 

PELYCODUS FRUGIVORUS, Cope, sp. nov. 

This species is known from a portion of the mandibular ramus, 

which supports the last two molars. The size of the animal is about 

half that of the Pelycodus jarrovii. The last molar is oval and narrowed behind. The lateral margins are raised, inclosing a concavity. 

The border is thickened behind at the heel and supports an inner anterior tubercle which has a lesser one at its anterior base. There are 

two obtuse external tubercles. The penultimate molar is robust, and 

two inner and one outer anterior tubercles; the former connected 

with the latter by ridges. A stout posterior outer tubercle sends an 

oblique ridge to the anterior inner, while the tubercle at the posterior 

inner angle is insignificant; enamel smooth, the external bases of the 

last two molars furnished with a cingulum. 

JJieasurements. 

M. 

Length of penultimate molar .................. ---o-· ........................... 004G 

Width of the same .. __ ....••••.•••••......•••..••••......• _ .•... _ ..•.• _. _. . . . . 0040 

Length of last lower molar....... .. .. • . . .. .. • . .. . . .. • • • . .. • . . .. .. .. . .. . . .. .. . . . . 0060 

Width oflast lower molar ...... ------ .•••• -----· ---- .......................... 0035 

Depth of ramus at penultimate molar_ .......................................... 0090 

Width of do. at same point ........................ ---· .............. -----· ..... 0040 

PEL YCODUS ANGULATUS, Cope, sp. nov. 

This species was probably less than one-fourth the size of the last described, and is represented in our collections by but few specimens. One 

of these is a portion of the mandibular ramus, with a single perfect 

molar; another individual is known from an isolated molar. The former 

displays the characters of the larger species, viz, a crown narrowed in 

front, where it supports three approximated cusps, and widened behind, 

where an elevated border embraces a basin-shaped concavity. In this 

species the anterior cusps are well defined and subequal in size, and the 

posterior angles of the posterior concavity each support a cusp. The 
15 

outer posterior cusp is connected by a strong oblique ridge with the 

posterior of the two anterior inner cusps. A well-marked cingulum 

surrounds the external basis of the crown, and extends round its front 

nearly to the anterior inner cusp. Enamel smooth. 

Measurements. 

M. 

Length of c~own of molar ......... --- ........•••..••••••..•...•••••.. -- ••• --.. . 0034 

Width of crown of molar •••• ·----·-----------··----··----·---· ............ -- .. 0027 

Depth of ramus at the same ............ ---- .......................... ·----· .... 0065 

Thickness of do. at the same .... ---- ............... - .. ---- .. ---- .... ---- ....... OOJO 

P ANTOLESTES, Cope. 

Proceed. Amer. Philos. Soc. 1872, p. 467. (Separata, August 30.) 

The type of this genus resemble in structural characters of the dentition of the lower jaw, the Hyopsodus and A.ntiacodon, already known 

in the collections of the different explorations of the Rocky :Mountain 

Jake basins. While it possesses the normal number of molar teeth belonging to these, it preserves a sectorial character of the premolars more 

posteriorly than in any of the allied genera. The typical specimen of 

the P. chacensis presents four premolar and three molar teeth., the fourth 

premolar alone remaining with the three true molars. The premolars are 

all two-rooted except perhaps the first. The fourth is a simple flattened 

triangular cusp1 with a small tubercle at the base behind, wanting the 

inner cusp of other genera. The molars exhibit the usual four cusps, 

the external crescentoid, the inner discoid in section, excepting the inner anterior, which is duplicated by an anterior twin-cusp of smaller size 

being closely nuited with it. The last molar bas a distinct fifth tubercle or heel. This genus is probably also quadrumanous. 

P ANTOLESTES CII.A.CENSIS, Cope, sp. nov. 

The mandibular ramus of this species is very slender in both vertical 

and transverse diameters. There is a minute tubercle at the anterior 

base of the fourth premolar. There is a very minute median tubercle 

on the posterior border of the first and second true molars, and no anterior ledge. The heel of the last molar is short, and the other tubercles protuberant. The mutmel is smooth, and there is no basal cingultun on either side of the teeth preserved. 

Measurements. 

1\L 

Length of bases of seven molars ..••.••••• ·----·------ ........ -----·----··----- .037 

Length of bases of three true molars ...... ·----· .... ------·----·------·----- ..... 018 Length of bases of last premolar ... _ ... ____ .. ____ .. _. __ ... ___ ... _-•..•. __ ... ___ .. 005 

\Vidth of bases of last premolar. ... ··---- ...... -----· .... ·----··----------· ..... 002;) 

Length of penultimate molar .......... -----· ...... -----------· .... ·----·------ .0055 

·width of penultimate molar .... ----------·-·- .... ·----· .... ------ .... ·--·-----· .0040 

~;fa~;ho~f1~~~tm~1~:~: ~ ~ ::::::::::::: ~ ::::::::::::: ~::: ::::::::: :~: :::::: :~:: ~~ :~8~8 Depth of ramus at fourth premolar .•.•. _ ... _. _ .... _ ..... _ .... _--- ...... _ ....... _ .0080 

This species is considerably larger than the type of the genus, P. longicaudus, Cope. (See Annual Report U.S. Geol. Survey Terrs., 1872, p. 

549.) 

OPISTHOTO:\ftJS, Cope, gen~ts novurn. 

R-epresented by inferior molar teeth of two species. These do not 

d.isplay a bifid or double anterior interior cusp, and the crowns exhibit 
16 

two anterior cones, and an inner cone and outer crescent posteriorly. 

The posterior crescent is well defined and is continued Oll a narrow crest 

to the anterior irmer tubercle. The posterior molar presents the peculiarity of a series of three cusps in olle lille, the median having another 

or lateral cusp near it. 

This genus is also probabl.v quadrumanous, but differs widely in the 

form of the last molar from Tomitheri~tm, Pelycodus, Pantolestes, etc. 

0PISTHOT0}1US .A.STUTus, Cope, sp. nov. 

Established on two posterior lower molars which were found in immediate associatioll, but not attached to the jaw. The penultimate molar 

has a convex cingulum ill front connectillg the two cusps, and a median 

posterior cusp of small size. The last molar has a wide ledge ill front, 

and the anterior cusp is on its outer side. 

It is separated by a valley from the middle cusp, which is the most 

elevated. Directly on its inner anterior aspect a stout cusp is attached, 

and eonnects by a low ridge with the anterior. The posterior cusp is 

elevated, conic, and median, and is connected with the central cusp except at its apex. There is no heel behind it, nor any cingulum on this 

or the anterior molar tooth. The enamel of both teeth is nearly smooth. 

Measurements. 

Length of crown of median lower molar ..•.•..•••••....•.......••••••.•••••. ' ... 

Width of crown of median lower molar ............••.•..••••.....•.••......•.. Length of crown of posterior lower molar ...•........•••.........•....•........ 

Width of crown of posterior lower molar in front ..••••..........••••.•••••...••• 

~f:v~t~o~ ;;;i~~i Jd~~ Ju-sp ~ ~~~:: ~:: ~:: ~~: ~:: ~ ~ :::: ~::::: ~: :: ~:::: ·.::: ·.::::: :::: 

0PISTHOTOMUS FLAGRANS, Cope, sp. nov. 

u. 

. 0065 

. 0060 

. 0085 

• 0050 

. 0045 

. 0050 

A larger species, belonging to this genus, is represented by a 

portion of the lower jaw,' from which the molars are broken, excepting the last. The outline of the base of the crown of the latter is elongate subtriangular, the base of the triangle being anterior. Tlw allterior fourth of the crown is a ledge with angulate border, and a tubercle 

at the outer anterior corner; the remainder of the crown consists of 

three elevated cusps, an external alternating with an internal and a 

median posterior. The inner and outer cusps are rather obtuse, and are 

separated by a deep notch; the posterior cusp is much lower, is obtuse, 

and has a still smaller tubercle at its inner basis. The surface of the 

heel is oblique, for the external anterior tubercle sends a ridge to the 

internal median cusp, so that the line of elevation of the crown is a zigzag of three limbs. 

llfeasurements. M. 

Length of crown...... . • • • • • • . . • • • . . . • • . • . • . . . . . . . . • . . . . • • . • . . . • . . . • . • . . . . • . . . • 012 

Width of crown anteriorly ...•. _ .•...•...••••........•...•...•...... -.-... -... . 006 

Length between first and third cusps .••.........••••.....••..•. -... ----...... -.. • 006 

Depth of ramus._ .. , .•••••.••••..•...••••..........•.•.•........•.•.... -... . . . . . 002 

APHELISOUS, Cope. 

The present genus is nearly allied to Pantolestes, but differs in the absence of heel of the last inferior molar, and the simplicity of the inner 

anterior tubercle of all the molars. The characters of the inferior molars are as follows: Premolars four, molars three; the latter subeqnal 

in size. Premolars compressed; the fourth with a heel, but no interllal 
17 

tubercle. Last two molars with four subequal angular cusps, connected 

ronnd a central concavity by their adjacent angles. Symphysis mandibuli with persistent suture. 

The affinities of this genus cannot now be ascertained, but the molar 

teeth are so much like those of the lumurine genus Anaptonwrphus, 

Cope, from the Eocene of -~Vyoming, as to suggest relationship. The 

premolars are totally different . 

.APHELISCUS INSIDIOSUS, Cope. 

Prut,,tomus insidiosus, Cope. Report on the Vertebrate Fossils of New l\Ipxie.o, 

1874, p. 14. . 

.ANTIACODO:N, l\Iarsll. 

Cope. U.S. Geol. Survey Terrs., Ann. Report 1872, p. 608. 

Two species are provisionally referred to this genus on account of their 

resemblance to the known species A. py,qmccus, Cope, and A.fwrcatus, 

Cope, but not definitely, because the premolar teeth are unknown in 

both cases. One of them is similar in size to the species mentioned, 

while the other is much larger than any of the allies, approaching the 

larger species of Orohippu:;;. 

ANTIACODON 1\<IENTALIS. Cope, sp. nov. 

Established on a portion of a ramus mandibuli, on which the first 

and second true molars onls remain. The fangs of the last premolar are 

stout, and evidently supported a robust crowu. The cusps of the true 

molars are, as usual, crescentic in section on the outer side; the posterior inner conic, while the double anterior inner is rounded on the 

internal face, and not flattened, as in many species. The second true 

molar has a uistiuct posterior median tubercle; there are no basal cingula except a trace between the external cusps. This species resem Lies 

the A. furcatus, but difl'ers materially from it, as from A. pygmwus in 

the deeper and more robust mandibular bone. 

1l1easurements. 

A. mentalis. A. PYttmrcus. :M:. M. 

Length first true molar·----· .... ·----···----··---··-----·----· ... 0044 .0043 

Width first true molar behind ...•.. ···--··----·------ .... ·----- .00:{3 .oo:n 

Depth ramus at front of m. :3 •• ;. ·---·- ---· ··---· ·---·· ·-·--· ••••. 00135 .0075 

Depth ramus at front of last premolar.·--·· ................ -----· .0078 .0055 

ANTIACODO~ CRAssus, Cope, sp. nov. 

Represented by a portion of the right 1nandibular ramus which supports the first and second true molars. It is a peculiar species, known 

among its allies by the obtuseness of the cusps and ridges of the crown. 

The double cu~p is thick, and the component apices little separated; 

the anterior only is connected with the external anterior tubercle. The 

posterior p<trt of the crown is wider than the anterior, and is quite concave. The onter border supports a stout tubercle; the inner, a very 

small one behind, and there is a small ledge representing the posterior 

median. The oblique riclge from the posterior external cusp is low, and 

the anterior cusps rise abruptl_y. The enamel is smooth and tlw cingulum is represented l>y a trace between the bases of the external tubercles. 

Measurements. 

M, 

Length of second true molar ....... ___ ..... ·-- .••.....••. _ ....•..•......... ---· .0080 

Width of ditto posteriorly ............. __ .. _ ....... __ .... -··· .............. -.... 0075 

Elevation at same p1 int. .. _ ....... _ ... _. _ .......... _ ..... _ .......•.... _ ... _... .0040 

Transverse dian;e~er of ramus .... ····-· .... -----· ............................... 0080 

2B 
18 

OROTIIERIUl\f, Marsh. 

Amer .. Jonrn. ScL and Art~, lt372. (Separata, p. 26.) 

0ROTHERIU:\t: VlNTAN"L'"l\I, ~farsb, l. c. 

Specimens, un(listinguishaule, from the description given as above 

cited, embrace dentition of both jaws. This has a near resemblance to 

that of Orohippus. 

IIYOPSODUS, Leidy. 

Report G. S. Geol. Sun·ey Terrs , I, p. 75. 

llYOPSODUS PAULCS, Leidy, l. c. 

Part of a single specimen is undistinguishable from this species. I may 

mention here that Hyopsodus vicarius is the proper name of a species 

described by myself as Jllicrosyops vicarius, and later by Dr. Leidy as 

Hyopsodus minusculus, l. c., p. 81. 

HYorsonus l\UTICULrs, Uope. 

Estlwnyx miticulus, Cope. Report on Vertebrate Fossils nf New Mexico, 1874, p. 8. 

Parts of several specimens of this species show that the molars are 

Eimilar in size to the B. paulus, but that it has a much smaller last inferior molar, which has snch a low heel as to resemble the corresponding 

tooth of the species of Esthony.x. The last two premolars are more 

robust than in H. pnulus and possess rudimental anterior basal tubercles 

of wbicb a trace only exists in the H.pa..ulus. The mandibular ramus is 

considerably shallower. and the species was probably more diminutive. 

PHEX ACODUS, Cope. 

Pah~ontolog·ical Bulletin, ~o. li, p. 3, 187.3; Report on Vertebrate Fossiis of New 

Mexico, 11:{74, p. 10. 

The dentition of the <mterior parts of the jaws of the species referred 

by me to Phenacodus is unknown, but tl.Je premolar and molar teeth are 

.similar in character to those of the genus Palrnochrerus of the French 

Eocene. The well-marked external crescents are, however, characteristic, and the details of structure of the molars so closely resemble those 

of Opisthotomus and Tomitheriwn that I entertain a suspicion that this 

genus is quadrnmanous. If so, it includes the largest of the primitive 

Eocene monkeys, the P. primmvus equaling the orang in the size of 

its j<lWS. There are abnndant specific peculiarities distinguishing the 

Freuclt and American species, the upper molars of the latter resembling 

in a greater degree the genus Ohreropotamus. 

PHENACODUS PRINLADVUS, Cope, 1. c., (p. 10.) 

PHEN.A.COIIDTJS ·o"MNIVORus, Cope, 1. c., (p. 11.) 

PHENACODTJS S"L'"LC.A.TUS, Cope, l. c., (p. 11.) 
lH 

PERISSODACTYLA. 

l\IE~ISCOTHERIUl\f, Cope. 

Report on the Vertebrate Fossils of New Mexico, 1S7 4, p. 8. 

l\lE:NISCOTHERIUM CHAMENSE, Cope, l. C. 

HYRAOHYUS, Leidy. 

llYRACHYUS SING"GL.ARIS, Cope, sp. nov. 

Represented by the maxillary bones and teeth of two individuals, 

one of which includes those of both sides of the cranium, with the molars and last two premolars. In Rize this species is less than the H. 

nanus, the smallest of the g·enus. The third and fouth premolars have 

two transverse crests each. of which the anterior forms the border of 

the crown and the posterior inarks its middle. The supernumerary cusp 

at the external anterior angle of the crown is well marked in both premolars and molars. The posterior transverse crest of the molars is 

less elevated than the anterior, as it approaches the longitudinal cusps. 

The latter are well joined togethPr, and are strengthened by an external 

vertical rib, which extends to the apex. There is a weak cingulum on 

the anterior base of the crown, which passes round the i:1ner base of 

the anterior internal cone, hut is wanting at the base of tlle posterior, 

and very weak on the posterior and exterior bases of the crown. Enamel 

smooth in young as in old teeth. 

il'Ieasurements. 

l'!f. 

Length of five posterior molars ................................................. 0330 

Length of third premolar...... . . . . . . . . . . . . . . . . . . . .. . . . .. . .. . . . . . • . . . .. . . . . . . . .0054 

Width of third premolar. ................................................ _.. .. .00!")6 

Length of second true molar.................................................. .0050 

Width of second true molar.................................................. .0100 

Length of three true molars. . . . • . . . . . . . . • . . . . . . • . . . • . . . . . . . . . . . • . . . . . . . . . . . . . . .OUO 

This species is, as observed in my preliminary report, the only representative of the numerous Hyrachyi of the beds of the Bridger formation. 

In my exploration of thi::;; horizon in vVyoming, I obtained remains of 

six species, in great abundance, so that the existence of a single small 

species in few individuals constitutes a. marked feature of the New 

Mexican Eocene fauna. The absence of Palceosynps, a genus perhaps still 

more abundant than Hyrachyus in \Vyoming, adds to the evidence in 

favor of the belief that the difference between the fannm of the respective localities is due to something more tllan the peculiarity of geographical diRtribution, lmt points to diversit,y of llorizotl or time, as is i~Hiee1l 

sufficiently in<licated by the study of the stratigraphy in \Vyoruiug. 

There the Green Hiver beds contain the same fauna as those nuder consideration, and underlie the Bridger formation. 

OROHIPPCS, l\farsh . 

.Amer. Journal Science and Arts, 1872. 

Thi:-:; genus has numerous near allies in the Fjoe,'tH'R of Ft'ance and 

the Gnited States, from which it has not _yet lwe11 di:-~ti11g·ui:shrd. I 

llave therefore instituted some comparisons for the pnrpose of ascertain-
20 

ing its characteristic peculiarities. The mandibular teeth are identical 

in structure with those of Lophiotherium, Gervais, with the exception that, 

in that genus, the first premolar is part of a continuous series, while in 

Orohippus it is separated by a diastema from tile second premolar. In 

comparison with Orotherium I find that the last premolar is ditl'erent 

in structure from the first true molar, while they are alike in the lastnamed genus. The anterior inner tubercle of the molars is simple in 

Orohippus, double in O't·other·iu1n. The superior molars described by 

Leidy under the name of Hipposyus strongly resemble those of Orohippus, but belong, as I now believe, to another genus. The inner cones are 

alw:"t.ys distinct in Orohippus, but confluent in Hipposyus; the latter also 

lacks the posterior median tubercle. 

After those of the genus Bathmodon, individuals and species of this 

genus are most numerous in the beds ofthe Green River .Eocene ofNew 

:Mexico. I therefore succeeded in obtaining a full representation of 

their structure, including dentition, etc. The latter indicates seven 

species, which differ very materialiy in size and proportions, but agree 

closely in general characters. They may be distinguished as follows . first by their mandibular bones and teeth, and second by tlleir maxillary teeth. 

~[andibles. 

Largest, last molar m .. 014 in length; ramus .020 in depth at last premolar; molars with a produced ledge in front ............ tapirinus 

Large, last molar, .012; ramus, .020; ledges not prominent. vasucciensis 

Smaller, last molar, .010; jaw, .020; ledges not prominent ...... index 

Small, last molar, .010; jaw, .014 ............................. major 

Small, last molar, .010; jaw, .<H25...... . ............... angustidens 

Smallest, last mola.r, .00t!5; jaw, .0135 ..••.....•......... procyon in us 

Superim· mola1·s. 

Neither external nor internal cingulum of the crown ......... ~species. 

External but no internal cingulum ...................... procyoninus. 

External and internal cingula present, but tile internal weak ... major 

et vasacciensis. 

External and internal cingula very strong, enamel rough. 

Larger, outer cusps flattened .. ~. . . . . . . . . . • . . . . . . . . . . . . . . . a,gilis 

Least species, outer cusps conic and well separated._ . cuspidatus 

It is evident from the above tablPs that I am not certainlv acquainted with the superior molars of 0. tapirinus, 0. index, and 0. an- gustidens, nor with the mandibular teeth of 0. cuspidatus. I have, bowever, numerous teeth which are not associated with those of the opposing series, and which <loubtless cover nearly tbe entire ground of 

comparisons. 

0ROIIIPPUS TAPIRINUS, Cope, sp. nov. 

Represented by mandibles with teeth of five indidduals, which exceed in Hize those of the species heretofore known, being larger thau 

the smaller llyrachyi. The opposite cusps of the molars are not separated by so deep a notch as in some of the other specie~, while the oblique ridges extending forward from the outer tubercles are well developed. The same is true of the ridge which exteuds from the prominent heel of the last molar. 'rhe anterior lellge is JJorizontal, and is 

bounded by a ridge which descends from the anterior external tubercle 
21 

and becomes transverse. It is less marked in all the other species. 

Enamel nearly smooth. The external cingulum is very faint on the 

last molar, but becomes more distinct on the anterior; none on the 

inner side. 

Measurements. 

M. 

Length of bases of last two molars, (No. 1) ........... -.-........ -... • . • . . . . . • . • . .025 

Length of base of penultimate, (No.1) ..................... ------." ........ ---- .011 

Width of base of penultimate . . . . . .. . • . . . . • • .. . .. . • . • . . . • • . . . . . .. • • . • • .. . . .. • .008 

Depth of jaw at penultimate ............ ------ ................................. 022 

Depth of jaw at last premolar, (No.2).......................................... .020 

ORO HIPPUS V ASACCIEXSIS, Cope. 

Lopltiotherium vasacciense, Cope. Proceedings American Philosophical Society, 1872, 

474. 

Ten individuals from our collections are referred to this species, some 

of which embrace portions of both jaws. 

Selecting as type a left mandibular ramus, which supports the five 

posterior molars, (the last broken,) it may be observed that the third 

premolar has a strong median cusp, with a small accessory one on its 

inner side, and a similar one immediately in front of it. The posterior 

base of the crown is expanded, and supports a single obtuse cutting 

-edge of little elevation. The only cingulum of the tooth bounds the 

outer and inner sides of this part of the crown. The fourth premolar 

is similar, except that the two median cusps are subequal, the anterior 

one much reduced, and the general form stouter. It differs from the 

first true molar, in the presence of a single posterior low cusp, which 

connects with the anterior by an oblique ridge. The opposite cusps of 

the true molars are well separated by fissnres, and the anterior ledges 

are but slightly developed. External cingula well marked; enamel 

wrinkled where not woru. 

Measuremeuts. 

M. 

Length of five posterior molars .................................................. 044 

Length of last two premolars .................................................... 013 

Length of last two molars...... . . . . . • . . . . . • . . . . . • . . . . . . . . . . . • . . . • • • . . • . . . . . . • . • .022 

Length of penultimate molar ..............•.............................••••••. 0085 

Width of penultimate molar .................................................... 0070 

Depth of ramus at last premolar. ................................................ 0200 

Depth of ramus at last molar.... . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • • . . .. . . . . .0220 

In a specimen with the last two superior molars the rather coarse 

wrinkling of the enamel is visible on the external face, although the 

teeth are well worn. The external tubercles are compressed cones connected by a ridge at the base. The accessory anterior external cusp is 

moderately developed. The cingula are distinct, but not prominent on 

both inner and outer side. 

11icasurements. M. 

Length of last two molars .......... __ ..........................•............... 0160 

Length of penultimate molar .................................................... 0085 

·width of penultimate molar ................................................ -.... 0100 

This species resembles the 0. tapirinus in the robustness of the jaws, 

but the teeth are materially smaller. 

0ROHIPPUS l.IA.JOR, l\farsb. 

Orohippus major, Marsh. American Journal of Science and Arts, 1874, p. 248. 

Between a dozen and twenty examples of this species were obtained. 
22 

ORO HIPPUS .ANGUSTIDENS, Cope, sp. nov. 

A number of jaws were obtained which resemble in general proportions those of the 0. procyoninus, but differ in the greater length of the 

last inferior molar. This tooth is as large as the corresponding one in 0. 

major, but the other teeth and the ramus of the jaw belong evidently to 

a smaller species, and one near to the least forms of the genus. 

Scleeting for deRcription a portion of a ramus which supports the last 

three molars, we observe the close resemblance between the latter and 

those of other species. The anterior ledge and posterior median tubercle are little developed; the oblique ridges are well developed, and 

the heel of the last molar elevated. The molars have a strong cingulum 

on the outer side, and the enamel is slightly rugose. The ramus is 

slender. 

nfeasurcments. 

1\L 

Length of bases of three true molars ....... -----------------·------·----------· .024 

Length of penultimate molar ............ --~--- .................. -----·........ .007 

'Width of penultimate molar .......................... -----· .......... -----·... .005 

Depth of ramus at last molar .......................... ---· ....•.•... -----·---- .012 

In another specimen of about the same size the bases of three premolars are preserYed, and measure .016 in length. 

0ROHIPPUS PROCYONIN'CS, Cope. 

Helotherium proryoPinum, Cope. Proceedings .American Philosophical Society, J 872, 

466, (August :n 

Orohippus pumilns, Marsh. American Journal of Science and Arts, 1672, (Aug. 7.) 

SeYeral specimens, with much of the dentition, accompany those of 

the other species. 

0ROHIPP'C'S AGILIS, l\Iarsh. 

Oro!tippus ngilis, American Journal of Science and Arts, 1873, p. 407. 

Some superior molars agree in size and other characters with those 

noticed by Professor 2\larsh, under the above name, so far as I can ascertain. 

OROHIPI'"CS CuSIJIDATus, Cope, s1J. 1Wi'. 

This is the least species of the g·enus known to me, and is known 

especially from a portion of the left maxillary bone which supports the 

first and second true molars. Other separated molars of the same character are not uncommon, and probably belong to the same species. 

The molars are characterized by their regularly quadrate form, the anterior external angle not being produced as in most of the species. Tbe 

first is also as long as broad, and is not narrowed as in others. Both 

molars are entirely surrounded by a strong cingulum, which is not interrupteu on the inner side of the crown, and rises into a low accessory 

cusp at the anterior external angle. The turbt>rcles of the tooth are 

conical, the outer circular in section and slightly connected by a ridge 

at the base. The median tubercles are well separated from the interior, 

and are conical, thus differing from other species. The enamel is coarsely 

rugose. The malar ridge overhangs the maxillary in a marked manner. 

The animal described was adult, but the cusps are not much worn . 

.JJJcasurements. 

M. 

Length of first anJ second true molars ...................... ----·-............ .0130 

Length of first true molar.. .. . . . . . • . . . • . • • . . . . . . . .. . . . . . . . • . . • • • • . . • • • • • • . . . • .OOfiO 

\Vidth of first true molar .................................. _.... .. • • • . .. . . • • • • .0065 

Length of Eecond true molar .............................. _ ........... _.. .. • . . 0060 

Width of second true molar .......................................... ----.... .0075 
Iu these ml~a:-~nremelltl'l the d.i:spa,I'ity iu \Vidth of the crowns of the 

first and second true wolard is a noticeable feature. 

RODENTIA. 

P ARA.:\IYS, Leidy. 

P ARA}IYS DJDLICATIOR, Leidy. 

Report U. S. Geol. Surv. Terrs., vol. I, p. 110, Pl. VI, figs. 26-7. 

P A.RA::\IYS DELICA.TISSIMus, Leidy, I. c., p. 111, Pl. VI, figs. 28-9. 

TOXODONTIA. 

In an essay published by the United States Geological Survey 

of the Terrs., dated February, 187 4, I discussed the origin of the great 

population of animal forms which previous explorations had disclosed in 

the lake deposits of Wyoming. The conclusion was that they had been 

derived by migration from the South, as geological investigations pointed 

to the earlier elevation of the land in that direction. During the summer of 1874, as paleontologist of the United States Geographical Explorations and Surveys, under Lieutmtadt Wheeler, I sought for and 

discovered a great mass of lacustrine deposits of somewhat earlier age 

than those of the Bridger epoch, Wsoming, containing the remains 

of a great number of animal species and genera, which so nearly resemble those of \Vyoming as to leave no doubt that the latter were derived by descent and migration from New Mexico and the South. 

In a memoir read before the Academy of Natural Sciences of Philadelphia, at or.near the same time, I stated that the primitive type of 

the mammals with convoluted brains "must have been bunodonts with 

pentadactyle plantigrade feet;"' that is, must have had tubercle-bearing 

grinders, and ha\Te had five-toed feet, "~boRe entire soles were applied 

to the ground in walking, and not merely the toes, as in most living 

higher mammals. It \\·as also stated that variations in the number and 

relations of the front teeth might be expected in such a hypothetical 

group of animals, which was named B-unotheriida:. During the explorations in ~ew .Mexico the following season a remarkable genus was discovered, and afterward named Calamoclon. Its jaws and teeth were 

discovered, and the latter had tubercle-bearing crowns. Subsequently l~rofessor J\Iarsh described more perfect specimens of related animals, 

which show that they are also five-toed, (pentadactyle,) and walked on 

the soles, (plantigrade.) \Vith other similar genera he forms an order 

Tillodontia,, and says that they are related to hoofed animal~ (Ungulata) 

and O(trn,ivm·a, and that tlwir brains were Rome,-rhat convoluted. This 

is a full confirmation of the anticipation above meutioned. 

It was also stated that the primitive Ungulate 'i cannot he far removed from tlte primitive Carnivore and the primitive quadrumane." 

The dentition of the genus Esthonyx bears a strong resemblance to that 

of certain quadrumana, especially of the genns Pelycorlus~ while the 

resemblance of the molars to those of Ectoganus is not less marked. 

In Oa.lamodon at·camrenus, Cope, the cia ws are eompressed, but less so 

than in recent Carnivora., and resemble more closely those of the Erlentata,, They have a doulJle trochlear articulation with the phalanges, and 

are without basal sheath. ·The extremity is somewhat fissured. 
24 

ESTHO~YX, Cope. 

Report on the Vertebrate Fossils of New Mf.'xico, 11'374, p. 6. 

ESTHONYX BISULCA1'US, Oope. 

Report, l. c., p. 6. E. acer, Cope, 1. c., p. 7. 

ESTHO~YX BURMEISTERII, Cope, l. c., p. 7. 

ECTOGANGS, Cope. 

Heport, loc. cit., p. 4. 

ECTOGANUS GLIRIFOR::\HS, Cope, l. c., p. 4. 

CAI.u\.:UODO?S", Cope. 

Report, loc. cit., p. 5. 

C.A.LAJIODO~ SDIPLEx, Cope, 1. c. 

C.A.LA:~\IODON ARCA~ICENUS, Cope, l. c., p. 6. 

CALA:i\IODON NOVO::\IEIIICANUS) Cope, 1. c., p. 6. 

Al\tfBLYPODA. 

BATHMODON, Cope. 

Proceedings Amer. Philos. Society, Jan., 1872. 

STRUCT"C"RE OF THE FEET. 

Fm·ejoot. 

A fore-foot of a species of this genus possesses five metacarpal bones, 

although I have as yet obtained the exact articulations of but four. Of 

these, the inner is the smallest, the second and third snbequal, the fourth 

as stout as the third, but a very little shorter, and the fifth a little shorter 

than the fourth, but as stout. These bones, as well as the phalanges, are 

very short, shorter even than those of the Elephantidcc. The carpus of 

this specimen retai_ns in place all of its elements, except the trapezium. 

The unciform is a transverse wedge-shaped bone, with the obtuse apex 

postero-exterior; the superior face gently concave in transverse section, 

the inferior convex. The posterior side is beveled slightly up toward its 

center. The magnum hasconsiderablevertical and antero-posterior extent, 

but is narrow in the transverse direction. The outline seen from the side 

is subtriangular; the superior side is a single antero-posterior facet; the 

inferior face is concave antero-posteriorly for the metacarpal articulation, and on the inner side is a narrow facet for the second metacarpal. 

The unciform is concave in the transverse direction above, and its inferior surface pre.sents three facets, of which the outer and middle are 

large. The inner facet presents the same obliquity as the external. 

This carpal presents an upturned inner superior border, which supports 

a facet contact with the lunar. Both the cuneiform and unciform have 

considerable transverse extent. The lunar has much less transverse 

extent. It displays a single conYex facet auoYe, and three longitudinal 

concave ones ueJow. One of the latter is nearly external, joining the 
25 

'Scaphoid; a concave facet on the inner side connects with the cuneiform. The two inferior facets then are applied to the unciform and 

magnum. The scaphoid has a hook-like posterior portion; superiorly 

it supports two approximated facets; it is rather smaller than the lunar. 

The trapezium is larger than the trapezoides. 

The transver~e extent of the cuneiform indicates a wide articulation 

of the ulna with the carpus. 

The indications of affinity derhyable from the fore-foot are the following: 

There are three lines of relation which present modifications of the 

carpal articulations, in passing from generalized to specialized forms of 

rnamrnaUa. 'l'he first is the cubito-carpal articulation; the second, the 

intercarpal; the third, the carpo-metacarpal. In the primary relation 

of the cubito-carpal articulation the ulna and radius take equal shares 

in it, or the ulna l1as the greater part. In the progress of specialization, whether it be as in the Quadumana to secure the rotary movement of the band, or as in the Artiodactyla and higher Perissodactyla, 

to acquire firnn1ess and solidity in connection with high speed, the 

successive modification consists in the reduction of the ulnar artieulation, and increase of the radial. The same successive modification is 

seen in the Carnivo'ra. The Elepha.ntidm exhibit the unmodified relation 

of the bones of the cubitus to the fore-foot, in the great extent of the 

ulno-carpal articulation. Bath mod on resembles it in this respect. .A. 

considerable reduction of the ulnar articulation is seen in the representatives of those different orders which approach nearest to the Proboscidia, the degree of reduction being somewhat similar in all, viz: 

Hyrax of the Hyracoidea; Rhinocerus of the Perissoda.ctyl a and Hippopotamus of the Artiodcwtyla.. The reduction continues from these points 

of beginning until it is rednced to a minimum in the highest representatives of the last two orders, Equus and Bos. 

In the composition of the first series of carpal bones the Oanlivora, 

some Rodentia, (Hystri;IJ,) and some J}[arsnpialia (llfacropus and Hypsipryrnmts) exhibit a coossification of the lunar and scaphoid bones; in 

Bathrnodon, as in most other j}'famrna.lia, these elements are distinct. 

In the intercarpal articulation we find in the simpler forms that the 

scaphoid bone joins two of the second row, trapezium and trapezoides; 

the lunar joins the magnum only; and the cuneiform the unciform on its 

distal face. This is the case with many rodents, monkeys, and with the 

elephantidm. In passing from this starting-point, we notice two lines of 

modification. The most important is seen in tile outer side of the foot, 

where the unciform is extended inward so as to ha\e a facet of articulation with tl1e lunar; the other change is on the inner side, where the 

trapezium and the corresponding inner digit disappear. The first-named 

modification does not appear in Hyrax, but is well marked in Bathmodon, 

and is about equally developed in Typotherium, GerY., (fide Burmeister.} 

It is still more marked in carnivo'ra and in Rhinocerus and Hippopotamus, 

and in the higher genera of the two orders represented by the last two 

nameu, the unciform facet occupies half or more of the distal end of the 

os lunare. The reduction of the tr<lpezium and its loss follow the same 

series. while in the higher artiodact.l}la the trapezoides alio!O oisappear by 

coossification with the magnum. As there are five metacarpals in Bathrnodon the trapezium and trapezoides are di.stinct. 

In the carpometacarpal articulation, the least modified t.rpes exhibit 

one metacarpal to each of the three inner carpals and two to the unciform. This relation is found in proboscidia. many rodents, (hystricidre,) 

carnivm·a,(hyaena., canis,) qnadrwnana, edentata,(rlasypu.s~) and rnarsupialia, 
26 

(macropus.) But in some of the crr.rnivora, e. g., felis and ttrsus, the middle 

metacarpal extends to the side of the unciform, causing the presence of 

a third distal facet of that bone, which is in these cases lateral. In the 

orders perissodactyla and art·iodactyla, both types of articulation occur, 

as has been pointed out by Kowalevsky. In these orders those genera 

without the third metacarpal facet of the unciform are principally 

extinct, while the living genera nearl.v all display the lateral facet for 

the third as well as the distal ones for the outer metacarpals. When, as 

in the higher artiodactyla, the exterior <ligit is wanting, there remains 

but 011e <listal facet of the unciform. . In Synoplothe'rium and the Toxodont genus Typotherium the facet of the 

unciform for the third metacarpal is lateral. In Bathmodon it is not more 

lateral than the external facet of the unciform. In Rhinocerus, Hyrachyu8, Palccotherium, Hyrax, Tamanilua, &c., it is oblique and subinferior. 

From the preceding it appears that Bathmodon resembles the El,epha.ntidm in the number of the digits of the fore-foot, in the short, wide form 

of the same, and in the composition of the cubito-carpal articulation. 

In the intercarpal articulation it resembles the Toxodont Typotherium and 

the Carnivora; in a lesser degree the lower Perissodcwtyla. In the carpometacarpal artieulation the resemblance is stronger to the Per·issodactyla 

than to any otl1er order. 

, Posterior foot. 

The least specializefl type of mammalian hind foot presents the following relation between tile bones of the tarsus; the na vicnlar bone supports three cuneiforms; the cuboid is in contact with the calcaneum 

only, and supports on its distal facets two metatarsals; each of the 

cnneiforms supporting a metatarsal. The totaJ number of the latter is five. 

This arrangement prm?ails in the Edenta.ta;, Quadrumana, and Cantivora, 

the inner cuneiform being often reduced in the latter and the corresponding digit wanting. In the more specialized forms of the same 

order the external digit iR thrust outward from the distal face of the 

cuboid by tile metatarsal bone of the penultimate dig·it. 

A striking modification of this type is seen in the Elepltantidcc, where 

the navicular bone is extended out\'ranl so as to separate the cuboid 

from contact with the astrag-alus. 

In the Hystricidw the arrangem<>nt only differs from that of the unspecialized foot, in tbe position of tl1e inner cuneiform, whieh is remO\?ed 

backward on the inner side of the tarsus, so as to be in contact with 

the astragalus. 

In Uugulata, with the exception of Elephantidw, the penultimate toe 

excludes the outer from the distal articulation of the cuboid. This toe 

is then loosely attached to the outer side of the cuboid, or in the great 

majonty of cases is altogether wantiug. At tbe same time the cuboid 

is widened inward so as to haYe some contact -with the astragalus. 

The 'vide cuboid exists in the Proboschlia, but is excluded from contact 

with the astragalus by the iuten?eution of the wide navicular; but in 

the Perissodactylc(; and Art-iodactyll(; the naYicnlar is narrower, being 

confined to a greater or less inner portion of the distal end of the astragalus. In most Peris.'wdactyla the resulting contact of the cuboid with 

the astmgalus is slight, but in Artiodactyla, it is Yery extensive, in 

the specialized forms involving half the extremity of tlw astragalus. 

In both of these orders the loss of the inner toe is common, and in many 

of the latter the inner cuneiform is also wanting. As is well known, 

the external digit is wanting from the hind foo~ of an existing· Perisso-
dactyla, while it is present in many Artiod(wtyla, while the inner is alike 

wanting in the living members of both orders. In the A.rt,iodactyla 

the second and :fifth diminish par-i passu to extinction in the higher 

ruminants, leaving the third and fourth ; while in the Perissodactyla 

the second and fourth present a coincident reduction of size to the condition seen in Equus, where the third alone remains. 

In the genus Bath1nodon we observe a generalized type of foot, with 

two slight modifications. As already described, the foot is short and 

plantigrade, and furnished with five digits. The calcaneum is short and 

fiat, and its heel is in curved; the astragalus is fiat, broader than long, 

and like the calcaneum· furnished with a facet for the :fibula. The 

navicular bone is not only thin, but shortened in the transverse direction. It supports entirely only two cuneiforms, the inner and median; 

the outer presents a narrow facet to it, but rests principally on the 

astragalus. The facet of the latter, to which it is applied, is well distinguished by an angle from that of the navicular, and is the one formerly supposed to be in relation with the cuboiU. Tile cuboid is in contact with the entire distal facet of the calcaneum, and extends a little 

further inward so as to have a slight contact with the astragalus also, 

as well as with the ectocuneifonn. Each cuneiform supports a welldeveloped digit; and the cuboill supports two, one on each facet of its 

distal extremity. 

In the characters of tlle calcaneum and astragalus, as in the articulation of the two outer digits to the distal face of the cuboid, this genus 

differs from all known Ungulata excepting the Elepha,ntidm. In the withdrawal of the navicular from between the overlapping ends of the 

cuboid and astragulus, it differs from Elephantid(e and resembles Per-issodactyla. In the three well-developed cuneiforms the resemblance is 

again to the Eleplwntidw, but in the further abbreviation of the navicular and articulation of the ectocuneiform with a facet of the astragalus. 

Bathmodon differs alike from Elephantidw al!d an other Ungulata. 

SUl\f:MA.RY. 

The structure of the feet of this genus indicate that it cannot be 

received into any of the orders of 1Jfam·malia without modification of 

their definitions. The greater number of the characters are those of 

Proboscidia, while some in both fore and hind feet are those of Perissodactyla, and others of the bind limb are peculiar. The general 

structure of the forefoot coincides nearly with that of the genus 

Typotherium * of tbe order To;rodontia, with the exception of the limited 

ulno-carpal articulation, which appears from a figure of Professor BurmeiRter's to be small, and thus totally distinct from that characteristic of 

Bathnwdon. In the hinder foot there are also both resemblances and 

differences. Thus the incun·ature of the calcaneum behind; its inward extension to support the astragalus, and the large calcaneo-:fibu1ar 

facet are in near relation to corresponding parts of oxod01~. But the 

latter genus is said to exhibit a single distal facet of the astragalus, that 

for the navicular, instead of two or three. 

Thus the claims of Bathmodon to enter the Proboscidia. on the one hand 

and the ToxodonUa on the other are about equal, and it cannot be placed 

with either without violating their definitive features. It becomes~ 

then, a question whether all three p;roups may not properly be combined 

into a single one. But this introduces another difficulty, namely, the 

"I am indebted to Professor Burmeister for information respecting the osteology of this 

genus. 
28 

impossibility of discrimination of the division thus constituted from the 

Perissodactyla. The characters distinctive of each of the three groups 

in question are also those that separate them from the Perissodactyla. 

Hence none can be ignored without the union of the four divisions into 

one. There is then but one taxonomic solution to the difficulty, and I 

therefore propose to regard Bathmodon as the tJ·pe of a distinct order of 

JJ1.ammalia, which will also include the genera Loxoloplwdon and Uintatherimn iu a distinct subdivision. The definition is as follows: 

Ord~r AMBI.YPODA. 

Ohar.-Fore li1nb.-Ulno-carpal articulation as large as or exceeding 

radio-carpal; antrorse. Lunar distinct, articulating with unciform; digits 

five, very short, with short wide hoofs; foot plantigrade. 

Hind limb.-'E,oot plantigrade, very short; calcaneum and astragalus 

transverse, fiat; cuboid bone uniting with both calcaneum and astragalus; digits four or five, short, with short wide hoofs. 

Hind foot of Bathmodon. 

]. Calcaneum; 2. Astragalus; 3. Cuboid; 4. Navicular; 5. Ectocuneiform; 6. Mesocuneiform; 7. Entocuneifonn. 

Suborder PANTODONTA.. A rudimental third trochanter of the femur; 

calcaneum with fibular facet; superior incisor teeth present. Genera 

Bathmodon, Jlfetalophodon and probably Ooryplwdon of Owen. 

Suborder DnwcERATA; no third trochauter; no fibular facet of the 

calcaneum; no superior iucisor teeth. Genera Uintatherinrn and Loxolophodon. 

The order Amblypoda is evidently more generalized in its foot structure than the Artiodactyla, Perissodactyla and Carnivora, but not more 

so than the Probosc,idia, from which it differs in the reduction of the 

outer portion of the navicular and the mutual articulation of the lunar 
29 

and cuneiform b~nes. It resembles armadillos and Glyptodons in the 

composition of the carpus, but not in the tarsus. 

More o.r less perfect specimens of one. hundred and fifty individuals of 

Bathmodon were obtained by the expedition. These I refer t.o seven 

species in which the dentition can be determined. They are distinguishPd as follows : 

I. The anterior outer cone of the superior molars larger, the posterior 

more crest-like, making a strong angle with the anterior; 

Superior canine compressed ................... -.. . . . B. molestus. 

II. Anterior cone smaller, posterior cresent wide; both in one line on 

l\1. 3. 

a. Iuferior molars with wide heel. 

Canine compressed, premaxillary bones elongate ... - ...... B. lomas. 

Canine triangular, premaxillary bone short., ...... ~ .. , .... B. sinms. aa. Inferior molars with very narrow or no heel. 

Large; premolars large, superior fourth .035 wide; lower molars longer 

than wide .............................................. B. radians. 

1\Iedium; fourth superior premolar .025 wide; lower molars elongate 

without posterior cingulum .....•.............. , ..... B. elephantopus. 

Medium; inferior molars nearly as wide as long; premaxi1lary bone 

short .................................................... B. latidens. 

III. Last lower molar with a conic cusp on the inner side. 

Last lower molar with narrow heel . . . . . . . . . . . . . . . . . . B. cuspitlatus. 

BATH:\IODON ELEPHAN1'0PUS, Cope. 

Report on Vertebrate Fossils of New Mexico, 1874, p. 10. 

BATHMODON LO:\IAS, Cope, loc. cit., p. 9. 

BATHl\IODON SIMus, Cope, loc. cit., p. 8. 

BATHl\IODON MOLESTUS, Cope, loc. cit., p. 9. 

BATHMODON LATIDENS, Cope, sp. nov. 

Represepted by both mandibular rami with dentition nearly complete, 

by the left premaxillary bone with its teeth, and by a right superior canine. These portions belong to a species of about the size of the B. elepha.ntopus, but one of a shorter and more robust form of skull. It differs 

in the same way from B. radians, besides being of distinctly smaller size. 

The rami are stout, especially below the last molars, and not shallow 

anteriorly. Posteriorly, below the last molar the inferior border retreats 

upward, so that the angle of the jaw is opposite to the superior fourth 

of the vertical diameter of the ramus at the middle. The inferior border 

of the angle is slightly deflected. The condyle has great transverse extent, and the coronoid process is recurved and broad in front. 

The canines are directed at an angle of 450 upward, and 900 outward, 

the apices turned backward ; the crown is subtriangular, and has a 

slightly alate anterior angle. External face convex, and without angle. 

Each is in contact with the external incisor, but is separated from the 

first molar by a diastema. There are fiye premolars on each side in this 

specimen, of which the second is probably intercalated abnormally, as it 

is smaller than the others. The crowns of the premolars are elevated, 

and their posterior crests short. · The true molars are characterized by 

their short anteroposterior diameter as compared with their transverse. 

The anterior descending crest is but little marked, and its termination 

at the inner extrmnity isnot prominent as in other species. The anterior 

tramwerse erest is distinctly higher than the posterior, and its posterior face is scarcely markell by the connecting rillge. The latter is 
30 

well marked on tile front of the posterior crest, while a very narrow ledge 

represents the wide cingulum of such species as the B. lomas. Enamel 

generally rather finely rugose. ,The premaxillary bone is short and elevated, and the teeth are large and with a rudimental cingulum on the 

outer face. Superior canine with triangular crown. 

Measurements •• 

Total length of jaw from angle to incisor alveolar border ........................ . 

Depth of ramus at third premolar. ............................................ .. Depth of ramus just behind last molar. ....................................... .. 

Diameter of ramus at last molar .............................................. . 

Elevation of coronoid process ................... -~ ............................ . "\Vidth of condyle .•.•.••••••.•........•••........•.•.••...•.......•.....•••... 

Length of dental series ....................................................... . Length of true tnolars ....................•.....•.•..........•................. Length of penultimate molar .................................................. . 

Width of penultimate molar .•••............•............•.....................• 

~-J~~~h o~~~::~~f~:~: ~ ~ ~:::::::::::::::::::: ~ ::: ~ ~:::::: ~::::: ~::: : ~::: ~:::::: Diameter of canines at base .................................................... . "\\ridth between bases of canines ............................................... . 

Length of crown of canines .••.....•..............................•...•....... 

The skull of tllis animal was about the size of that of a bull. 

BA.TH~IODO:N CUSPID.A.Tus, Cope, sp. nov. 

M. 

• 306 

. 063 

• 035 

. o:~5 

. 160 

. 080 

. 156 

. 080 

• 030 

. 027 

. 0335 

. 0260 

. 032 

. 05:l 

. 063 

Represented by a portion of a mandibular ramus, which supports the 

last molar. The posterior transverse crest of this tooth is low, and sends 

a well-marked oblique ridge to the anterior crest. A cingulum projects 

from the posterior base of the crown, which is nq,t very prominent, and 

disappears at the base of the inner end of the transverse crest. Just external to and in front of this extremity a prominent conic tubercle is 

directed upward and inward. This process is not seen in any other of 

the numerous jaws and teeth in my possesRion. Enamel slightly rugose. 

Jtfeasurements. 

M. 

Width of molar behind . . . . . . . . . . . . . . . • • • . . . . . . . . • . • . . . . . . . . . . . . . . . . . . . • . . . . . . . 023 

Elevation of conic cusp...... . • • . . • . . . • . . . . • • . . . . . • . . . • . • . . . . . . . . . . . . . . . . . . • . . . 006 

This species is probably about the size of the B. lorncts. 

RECAPI'L'ULA.TION. 

The preceding catalogue includes the following representation of the 

Mammalian orders. 

Carni \Tora ............ _ ................... ~. . . . . . . . .. . . . . . . . . . . 11 

Insectivora* ....................... _....... . . . . . . . . . . . . . . . . . . . . 2 

Incertm Seuis........ .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

Perissodactyla _ ................. ~ ................. ~ _.. . . . . . . . . 9 

Rodentia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ~ Toxodontia ................ w • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 6 

Amblypoda ........................ ·.·......................... 6 

50 

*A genius of this order from the Miocene of Colorado has been termed by me Isacis, (Ann. 

Rept. U.S. Geol. Surv. Terr., 1873, p. 470.) As this name is preoccupied it may be replaced 

by Mesodectes. 
01 

_REP1,ILIA. 

OROOODILIA. 

DIPLOCYNODUS, Pom. 

DIPLOCYNODCS SPHENOPS, Cope, sp. nov. 

Indicated by a fragmentary skeleton, in which occur numerous portions of the cranium and vertebrre; a second specimen includes corresponding parts, with more numerous vertebrre. In both the distal part 

of the mandibular ramus is preserved, and shows two enlarged teeth inserted close together, the posterior opposite to the posterior border of the 

symphysis. In front of these there is an edentulous space; behind them 

is a series of quite small teeth. The dentary bone is quite narrow at 

this point, indicating an acuminate symphysis and muzzle. 

The type specimen includes the frontal and parietall>ones; the former, 

united, are not expanded, but are about as widQ as in Orocodilus elliottii, 

Leidy. The interparietal face is plane and narrow; its lateral l>orders 

sharply defined, including two rows of deep pits. The front is rough, 

with deep pits, which ha\e a transverse direction opposite the postfrontal bones; anteriorly they are smaller and less pronounced. The 

lateral olfactory ridges of the inferior surface are not strongly defined. 

The sculpture of the lower jaw consists of rather distant impressed 

punctiform pits in shallow depressions. A larger mandibular tooth is 

smooth and not sulcate at the base. A cervical vertebra has a short, 

obtuse, simple hypapophysis, not connected with the parapophyses. Its 

cup is a little deeper than wide; surface near articulations, smooth; a 

dorsal with ltypapophysis and lateral capitulum, has a depressed centrum ; fragments of the jaws are coarsely-pitted rugose. 

The second specimen is of a larger crocodile, and presents similar 

characters. The third and fourth cervicals show the hypapophyses aud 

parapophyses fused together into a crescentoiJ mass below the artieular cup, as in D. subulatus, Cope. The dermal l>ones are large, not keeled, 

and coarsely pitted. 

!Jleasu1·ements of No. 1. 

Width of parietal bone.·----------- ____ ---------···---------·-----·-----·------ ·width of frontal at orbits .. ___ .. _____ . _____ . ___ • _. ____ . __ . _ .••• -- .• --- .. -- .. ---

Depth of ramus at two canines. __ .. _____ . _. ___ . __ . ___ .. ___ -- .... ____ •. ----•. -----

Depth of ramus just behind two canines. ____ -·. __ ---. __ ----·.------.------ .• ---· 

Width of ramus at symphysis posteriorly·----·------·----·-----·----·-----·----- Length of a cervical vertebra .. __ . __ . _. __ ..... ___ .. ___ . _ . _ .... _. _. __ -- _----- . ---

Diameter of cup ~ ~~~~~~\~~ ·. ~ ~ ~ ~: ~ ~ ~ ~ ~ ~ -_ ·_ ·. ~ ~ ~ ~ ·_ ~ ~ ---- ~ ~ -. ·_:: ----::: ~:: ~ ~ ~ ~ ~ ~:::: ::: ~ 

T!Je size of the Alligato1· mississippiens·is. 

CROOODILUS, Linn. 

],f. 

• 013 

• 04:~ 

. 037 

. 030 

• OiO 

• 048 

• 0:!2 

. 021 

Remains of species of this genus are exceedingly abundant, chiefly in 

the upper beds of the formation, ·associated with gar fishes. The lower 

beds contain the greater number of mammalian remains, with a smaller 

percentage of croco(liles. The latter do not include any gavials, and 

resemble in some degree those of the Bridger group, some of the species 

being probabl.v identical. 

The New .Mexican species are naturally divided into those with flat 
32 

fr011tal bone, with the inferior ridges little developed, and those in 

which the interorbital region is bounded below by strong orbital or 

olfactory crests. In the latter the superior plate is narrower and 

thicker. 

CROCODILFS Gl1YP-cs, Cope, sp. nov. 

Established on remains of two individnals which are in a fragmentary 

state, including portions from all parts of the skeleton. The teeth are 

of uueqnal sizes, and are round in section in the anterior half of the 

jaws, are conic, and compressed a,t apex, curved, and with delicate opposed cutting edges which extend to the base of the crown. The middle 

of the length of the crown is delicately rugose striate. A large premaxillars tooth occupies a position a little anterior to the lateral notch. In the 

low·er jaw a very large tooth occupies a position opposite the posterior extremity of the symphysis, the latter marking the middle of the alveolus. 

Three teeth of much smaller size follow posteriorly in close succession, 

and are followed by a fossa to receive the apex of a superior tooth. The 

ramus is wide at the symphysis. 'l'he extremity of the lower jaw supports a large tooth close to the symphysis, which is followed by one of 

half its diameter. A part of the posterior outer side of the ramus is 

deeply pitted. 

In the second specimen a part of the frontal bone shows that part of 

the cranium to be deeply and rather irregularly pitted. The orbital 

border is wide and shallow, and the lateral olfactory ridges not prominent. There are three larger teeth on the median posterior part of the 

mandibular ramus, whicll is thin, rather slender, and but little rugose. 

The premaxillary bone and tooth are as in the first specimfm. Another series of fragments, perhaps belonging to the same individual as 

the last, includes numerous vertebrm and other skeletal elements. A 

cervical vertebra bas a prominent hypapopbysis with long base, and is 

free from the parapophyses. There are rugose lines between the latter 

and the edge of the cup. The dorsals have a bypapophysis with short 

base, and have a prominent shoulder with smooth surface bone. In the 

articular cups the tran~verse slightly exceeds the ve:ctical diameter. The 

caudals are of moderate length. The condyles of the femur are of unequal size, and the bead not expanded. 

Measurements. 

No.1. 

M. 

Width of ramus at symphysis ............................... ""·--··----· .... ·--- .0:~0 

Diameter of large alveolus at :,ymphysis .•••.. ··---···----···----· ....•...•••. ---- .015 

Length of bases ·of four teeth following .................................. -.... -- .•• 029 

Diameter of large premaxiilary tooth ............................ ·----- .... -----· ..• 010 

Diameter of anterior lower inc= s Jr .......................................... - .... -.. . . . • . 013 

Width of ramus at second incisor .................................. --- . ----. . . . . .. . o:n 

No.2. 

Width of frontal bone above orbit to inferior groove .••••••.••••.•••..•.•. ----•• -.•• 02(} 

Depth of ramus near middle ... __ ......... __ .. _. __ ...•••.•••••••••.•••.. -- ••••... - . 032 

Length of cervical vertebra ....•...•.••.....••••••••••••.••...•••..• -•••.• ---. .. • 038 

Width at articular ball .................. _ ............................. -.- ..•...•. 025 

Length of a dorsal ....................................................................... 037 

Width at articular cup .................................................................. 025 

J .. ength of a caudal .......................................................................... 043 

In comparison with a common large species of the Bridger formation 
33 

from vVyomiug, which agrees with such characters as can be found in 

the descriptioH of C. affinis, Marsh, I find the position of the large 

mandibular tooth is quite different, its position being considerably anterior in the Wyoming species. The first incisor tooth is also less enlarged in the latter. 

0ROCODIL US WHEELERII, Cope, sp. nov. 

This croco<lile is known from remains in the same fragmentary condition as those already described. There are numerous portious of the 

cranium with vertebrrn. 

This species is at once distinguished by the relative width of tbe interorbital portion of the frontal bone, and the slight development of the 

lateral inferior ridges. The pitting is relatively smaller than in any of 

the others here described, numbering five or six rows on the parietal region; there is a smooth border of the superciliary edge. The frontal has a 

narrow anterior prolongation between the prefrontals, longer than in " C. 

a;ffinis," and without the transverse impression preceded by a smooth 

space seen in that species. The pitting is, on the other band, gradually 

reduced toward the nasal region. Other cranial bones are strongly 

sculptured. A portion of the maxillary contains teeth. These are robust, with slightl.Y compressed obtusely conic crowns, with rugulose 

enamel. 

A cervical vertebra is elongate with short h:ypapophysis, free from 

the parapophyse~; its ball is subcircular. 

Measurements. 

M. 

Length of frontal bone, (10 mm. supplied) .•••••.....•..•..•.•..•..••.•..•...•... .130 

Length of anterior production of do .••• -..• -••......... ! • • • • • • • • • • • • • • • • • • • • • • • • • .05~ 

With of do. at front of orbits ...••....••............••......•.....•. _ .•..... __ .•. 037 

Width of do., by to inferior groove posterior ...................................... 03(} 

Depth of mandible at cotylus ...............................•..••.••..•....•••.... 053 

Length of a cervical vertebra ..................... - • . . . . . . . • . . . . . . . . . . . . . . . . . . . • . .04:~ 

Width and depth of ball of do ..•••.... -- ...... -......•.• : ............... _.. .. .. .02G 

Length of a lurnbar ...•...•••.•.•...••................••••....••.•.............• 042 

The size of this species was equal to tbat of the fully-grown Louisiana alligator. 

0ROCODILUS ELLIOTTH, Leidy. 

With this species we enter the second group of the genus above 

noted where the frontal bone is stout and furnished with prominent inferior ridges. The specimens referred prov1sionally to the C. elliottii 

embrace cranial bones and teeth, but I do not consi<ler the reference 

final. 

CROCODILUS LIODON. l\Iarsh, 

Amer. Journ. Sci. Arts, 1871, p. 454. 

Two individuals with depressed dorsal centra and articulated dermal 

scuta approach the description abo\e cited sufficiently to render it 

necessary to make this provisional identification. The frontal bones are 

not preserved. 

CROCODIL US CHA:MENSIS, Cope. 

Report on Vertebrate Fossils of New Mexico, 1874, p. 15. (Alligator.) 

Besides the type-specimen, I obtained a fragmentary cranium and 

3 B 
34 

numerous dermal scuta of another individual. The muzzle is wide and 

flat, and is emarginate at the sides, for the accommodation of the large 

mandibular tooth. This species must, therefore, be referred to the genus 

Crocodilus. The cranium is very rugose above, especially on the muzzle. 

The interorbital part of the frontal bone is narrow and thick, and with 

strong inferior crests and the superior surface covered with numerous 

closely placed round pits, of which five and six may be counted between 

the orbital borders. The extremity of the quadrate bone is concave 

transversely, and the anterior end of the condyle is not or but little 

wider than the posterior. A prominent ridge extends from the latter, 

forming a posterior alate border of the quadrate. Inferior face of 

quadrate concave. The dermal scuta are very few of them keeled, and 

they are mostly united by suture. Their surface is covered with rather 

sma11, sharply-defined pits. 

This crocodile is, perhaps, double the size of the Crocodilu.~ heterodon, 

Cope, which I formerly referred to Alligator, but now, by analogy with 

its ally the C. charnensis, place here. 

CROCODILUS HETERODON, Cope. 

Alligator hetcrodon, Cope. Proceed. Amer. Philos. Soc., 1872, p. 544; U. S. Geol. 

Surveys of Terrs., 1872, p. 614. 

The smallest species, represented by remains of two individuals, one 

of them adult. 

LACERTILIA. 

Remains of two species of this order were obtained, one of which resembles, in the portions preserved, the genus Glyptosaurus. 

TESTUDINATA. 

Besides the descriptions from the carapace and plastron given below, 

I may mP-ntion some vertebrre whose correct reference cannot now be 

made. These are opisthocmlian with well developed zygapaphyses 

and a mass of a depressed O\Tal form for neural spine. The centra are 

compressed and elongate, and indicate a long tail as in the genus 

Chelyd1·a. The diapophyses are well developed, and the chevron facets 

are excavated and continuous with the posterior cup. 

TRIONYX, Geoffr. 

Species of this genus were exceedingly abundant during the Eocene 

period, in New ~fexico. Over consideraqle tracts where other fossils 

are rare, these are commonly found. They present considerable uniformity of sculpture, and mostly have the coarse character of the creta· 

ceous species rather than the delicate patterns of surface of the existing 

and many of the l\fiocene species. The only species which appears to be 

identical with those of the Bridger formation is the T. uintaensis, Leidy. 

The characters are as follows : 

I. Costal bones with transverse ribs at their distal ends. 

A. The dermal ossification extending beyond the bases of the freerib ends. 
35 

T. LEPTOMITUS. Costal ridges numerous and close together. 

T. CARIOsus. Costal ridges narrow and widely separated. 

AA. Dermal ossification graduating into the free-rib end. 

T. RADULUS. Surface ridges numerous. 

II. Costal bones with the honey-comb sculpture nearly to their ends. 

T. UINT.AENSIS. Seulpture uniform . 

.All of the above species are of considerable size, and the bones of the 

carapace and plastron are rather thick. The sculpture of the median 

portion of th~ carapace is in all a coarse, uninterrupted honeycomb; 

that of the plastron is of finer character. To T. leptomit-us, Cope, I refer four individuals; to T. cariosus, Oope, six individuals; to T. radulus, 

Cope, tb1·ee; and to T. uintae'nsis, four. Many other specimens are not 

finally classified, owing to the absence of the essential parts of the cara pace, etc. · 

PLASTOMENUS, Cope .. 

U. S. Geological Survey Terrs., 1872, p. 617. 

Portions of the ~keletons of species of this genus are very abundant 

in the Eocene of New Mexico. Though one seldom obtains an entire 

carapace or plastron, the form, size, and sculpture indicate that the remains belong to several species. The figures, composed of ridges, pits, 

&c., variously distributed, are often quite elegan~. The species do not 

attain the average size of the Trionyches of the same era, but the P. 

communis, P. lachrymalis, and P. catenatus exceed in dimensions the 

living species of North American waters. 

Among the very numerous remains, no marginal bones occur, and the 

extremities of the ribs are either very short or do not project at all. 

A sternal bone of the P. corr1tgatus resembles that already described* in 

inclosing a fontanelle by one of its inner borders, while the bridge is 

well developed. The specific characters are as follows : 

I. Carapace with corrugated ridges, more or less inosculating; 

P. CORRUGATUS. Ridges fine, inosculating little; no welts. 

P. FRACTUS. Ridges fine, inosculating much, and thrown into oblique 

welts. 

P. CATENATUS. Ridges as wide as the interspaces, inosculating more or 

less; no welts. · 

II. Sculpture coarsely or finely punctate. 

P. COMMUNIS. Costals with coarse pits and distinct oblique welts. 

P. LACHRYMALIS. Costals with finer pits; the welts broken into tubercles posteriorly. 

P. 'l'HOMASII. Cope l. c., p. 618. Costals with approximate transverse 

ridges, separating one or two rows of pits. 

I have selected, as typical of the above species, four individuals of 

P. (~) thomasii; one of P. lachrymalis; eight of P. communis; two of 

P. catenutus, and a considerable number of the remaining two species. 

*Annual Report U. S. Geol. Surv., 1872. 
36 

BAE~A, Leidy. 

BAE~A ARENO~A. 

Leidy's Report U.S. Geol. Survey of Territories, I, p. 161. 

One specimen outained. 

DER~1ATE~lYS, Gray. 

DER:MATE:!.\1YS (~) COSTILATUS, sp. nov. 

Six individuals contribute fragments to our knowledge of this species, 

but \Yithout the completeness desirable. The species is essentially characterized by the presence of an elevated but obtuse rib, which crosses 

the costal bones at right angles to their length. As CQstals with all 

degrees of definition of the rib are preserved, I suppose that it disappeared at the middle of the carapace, or only existed on the posterior 

portion. Associated with the costals are vertebral l>ones, with a similar but more pronounced rib on the median line. This, also, is faint or 

wanting on associated vertebrals. I therefore suppose that this keel, 

also, is confined, as in the D. wyomingensis, to the posterior extremity of 

the carapace. Other portions of the skeleton are of uncertain reference, 

but there are associated in four of the specimens portions of carapace 

with the free borders marked by a broad, smooth band, which thickens 

inwards to an abrupt descending margin. The surface of this border 

is regularly marked with parallel obtuse ribs. The vertebral bones, on 

which the median rib is obsolete, have their lower surface produced in 

a projecting point on each side of the rather narrow excavation for the 

extremity of the vertebra which precedes it. The size is about t.hat of 

the Dcrmaternys toyorn·ingensis, and the robustness of the bones simi· 

lar. 

The reference of this species to the genns Derma.ternys is provisional 

only, and is based on specific resemblances to the J). wyomingensis, 

Leidy. 

EMYS, Broug. 

EMYS LATILABIATUS, Cope. 

Paleontological Bulletin, No.3, page :3, U.S. Geolog. Survey Tens., 1872, p. 626 . . .A bun dan t. 

ElVIYS (~) STEVENSONIANUS, Leidy. 

Report U.S. Geol. Survey Terrs., I, p. 141. 

Specimens in which the lip of the anterior lobe of the plastron is not 

incised at the sides are provisionally referred to this ~pecies. 

HADRIA~US, Cope. 

HADRIAN US CORSO Nil, Leidy, ( Testudo.) 

Cope, Amer. Report, U. S. Geol. Surv., 1872, p. 631 . 

.Abundant remains of a species of this genus are too fragmcutary for 

final reference. The characters derived from the forw~ of the lobes of 

the carapace are those of this species rather than of the others described, 

viz, H. octonarius and H. allabiatus. 
37 

PISCES. 

The only fishes discovered by my exploration of the Green River beds · of New Mexico are gars, probably of the genus Olastes, Cope. Individuals are abundant, but the number of specimens in which the jaws and 

teeth are preserved is too few to permit of satisfactory comparison with 

the species of the Bridger group, described in Hayden's annual report 

for 1872. The scales, &c., do not present marked peculiarities. 

Besides these, there occur, as already noted, (Report Foss. Vert. New 

Mexico, 1874, p. 4,) the teeth of Reveral species of sharks. These are, 

two of Lamna, one of Oxyrhina, two of Galeocerdo, and. one fragment 

apparently pertaining to Oarcharodon. The teeth resemble those of 

known species -of the Cretaceous formations, and generally have a worn 

appearance. With them were portions of oysters, and both have the 

appearance of having been transported. 

RECAPITULATION. 

Mamma.iia...... • • • • • • • • • • • • . . . • • • • • • • • • • • • • • • . • . • . . . • • • • • . . • • • • • . . • • . • • • • • • • 50 

Reptilia • • • • • • • • • • • • . • • • • . • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 24 

Crocodilia... • • . • • • • • • • • • • • • • .. • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • 7 

Lacertilia .•••••••••••••••••••••••.••••••••••••••.• ~ • • • • • • • • • • • • • • • • • • • • • • 2 

Testudinata • • • • . • • • • • • • • • . • . • . • . • • .. • • • • • . . . • • • • • • . • • • • • • • • • . . • . • • • . • . • • • • 15 

Pisces •••••••••••••••••••••••••••••.•.•.••••••.••............... -. . . • . • • • . . . • • 8 

82 

Published April 17, 1875. 

0