Late Cenozoic Ostracoda From 

Midway Island Drill Holes

GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F
Late Cenozoic Ostracoda From 

Midway Island Drill Holes

By JOHN C. HOLDEN

GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F

A description of ostracode assemblages 

from two cored holes through the 

reef cap of Midway atoll

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1976
UNITED STATES DEPARTMENT OF THE INTERIOR 

THOMAS S. KLEPPE, Secretary

GEOLOGICAL SURVEY

V. E. McKelvey, Director

Library of Congress Cataloging in Publication Data

Holden, John C

Late Cenozoic Ostracoda from Midway Island drill holes. 

(Geology of the Midway area, Hawaiian Islands) 

(Geological Survey professional paper ; 680-F) 

Bibliography: p. 

Includes index.

Supt. of Docs, no.: I 19.16:680-F

1. Ostracoda, Fossil. 2. Paleontology Cenozoic. 3. Paleontology Midway Island. I. Title. II. Series. III. Series: 

United States. Geological Survey. Professional paper ; 680-F.

QE75.P9 no. 680-F [QE817.08] 557.3'08s [565'.33'099699] 75-619048

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 

Stock Number 024-001-02683-0
CONTENTS

Abstract ______ _ ___ 

Introduction ______ _ _ __

Major assemblages _______________

The faunas ______________

Reef hole _________ _ __

Sand Island hole _________ 

Correlation ____ ____ __

Age _____________________________

Biogeographic affinities of the faunas 

Systematic paleontology _ _ . 

Genus Neonesidea ____________

Havanardia __ __ 

Triebelina ___ - ___ 

Paranesidea _________

Bairdoppilata ________

Bythocypris _________

Anchistrocheles _ _____

Macrocypris _______

Macrocyprina ________

Potamocypris ______

Paracypris ____..__ __

Aglaiocypris _______ 

Pontocyprella ______

"Hemicythere" _______

Caudites ________

Orionina ________

Pokornyella ______

Radimella _______

Aurila _________

Procythereis _______

Page

Fl 

1 

3 

7 

7 

9 

9

10

10

11

11

14

15

16

17

18

18

18

19

19

19

19

20

20

20

20

21

21

22

23

Systematic paleontology Continued 

Genus Muellerina ____________-

Quadracythere ___ - 

Jugosocythereis _- 

Tenedocythere _. 

Hermanites ___ - 

Cletocythereis ___ - 

Hammatocythere _. 

Neocaudites __ _ - 

Occultocythereis __ . 

Platycosta __ - 

Cyprideis __ - - 

Semicytherura . 

Hemicytherura _______

Bythoceratina _ __. 

Paracytheridea _ __. 

Parakrithella _ _ - 

Callistocythere _ . 

Loxoconcha __ _ _- 

Loxoconchella _ ___. 

Paradoxostoma ____ .

Pellucistoma _____ .

Munseyella -____-_. 

Xestoleberis _______.

"Cythere" ____ .

Ostracode __________-___.

Genus Cytherella _ . 

Cytherelloidea ________

References cited ______ _.

Index __ .

Page

F23

23

24

25

27

28

28

28

29

29

29

30

30

30

30

30

31

32

33

33

34

34

34

36

36

36

37

38

41

ILLUSTRATIONS

[Plates follow indexJ

PLATE 1. Bairdoppilata, Havanardia! Pokornyella, Triebelina, Bythocypris, Radimella, Caudites, Tenedocythere, and Munseyella.

2. Radimella, "Hemicythere," Tenedocythere, Aurila, Pokornyella, and "Procythereis."

3. Hammatocy there!, Orionina, Tenedocythere, Quadracythere, and Jugosocythereis.

4. Jugosocythereis, Hermanites, Loxoconcha, Cletocythereis, and Platycosta.

5. Loxoconcha, Hermanites, Muellerina!, Tenedocythere, and Quadracythere.

6. Cytherelloidea, Loxoconchella, Parakrithella, and Cyprideis.

7. Neonesidea.

8. Neonesidea!, Havanardia!, Havanardia, Triebelina, and Paranesidea.

9. Paranesidea and Bairdoppilata.

10. Pontocyprella!, Paracypris, Caudites, Macrocyprina, Potamocypris!, Macrocypris!, and Aglaiocypris.

11. Anchistrocheles, Munseyella, Orionina, Pokornyella, Aurila, and Radimella.

12. Hammatocy there!, Hermanites, Tenedocythere, Jugosocythereis, Quadracythere, Neocaudites, and Occultocythereis.

13. Platycosta, Hermanites, Cyprideis, Semicytherura, Bythoceratina, Hemicytherura, Parakrithella, Paracytheridea, and 

Callistocythere.

14. Callistocythere, Loxoconcha, and Jugosocythereis.

ill
IV CONTENTS

PLATE 15. Loxoconchella, Paradoxostoma, Pellucistoma, and Xestoleberis.

16. Xestoleberis, "Cythere," Cytkerella, Cytherelloidea, Aurila, and ostracode sp.

17. Xestoleberis, Cytkerella, Quadracy there, and Parakrithella.

	Page 

FIGURE 1. Map of Midway atoll, showing location of drill holes ___.____________________ Fl

2. Species checklist for the Sand Island hole __________._______________- _ 3

3. Species checklist for the reef hole _____________.__ __ _ __ - __ _ _ 4

4. Length-height plot of Neonesida kauaiensis ___________.___ ___ - __ _ _ _ - 13
GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

LATE CENOZOIC OSTRACODA FROM MIDWAY ISLAND

DRILL HOLES

By JOHN C. HOLDEN

ABSTRACT

Two drill holes 6.5 km apart on Midway atoll penetrated 

157 and 385 m, respectively, of Cenozoic sediment containing 

a rich collection of ostracodes. The reef hole, the deeper of the 

two, contains nine ostracode faunas; the lower faunas are 

earliest Miocene or latest Oligocene in age. An early Miocene 

age is favored to agree with foraminiferal ages. The Sand 

Island hole contains five faunas, of which the upper three 

are questionably assigned a Pleistocene age and are correlative with the upper reef hole faunas. All indicate shallow 

water for the sediments in which they occur, and some are 

interpreted as cooler water faunas (cooler than tropical). One 

fauna in the Sand Island hole is characterized by a great 

abundance of Cyprideis beaconensis, indicating local brackish 

environmental condition.

Of the 115 taxa recorded, 25 are described as new, 10 as 

new subspecies, and 50 are described under open nomenclature. 

The paleobiogeographic affinites are diverse. The lower Miocene section of the reef hole and, to a lesser extent, the upper 

Miocene sections of both holes are clearly linked to Caribbean 

middle Tertiary ostracode faunas, whereas the post-Miocene 

sections are dominated by Holocene tropical insular Pacific 

species. Some elements with affinities to the Japanese region 

are also present in the late and post-Miocene faunas.

INTRODUCTION

Midway atoll is about 2,700 km (kilometres) 

northeast of the Island of Hawaii and about threequarters of the way along the Hawaiian Ridge. This 

ridge is a fairly straight chain of tholeiitic volcanic 

mountains running from Hawaii at its southeast 

extremity to Kanmu Seamount at long 175° E., lat 

32° N. Interest in the Hawaiian Ridge has increased 

in recent years because of rapid progress in tectonic 

theories. The ridge may prove to be of paramount 

importance in deciphering the geologic history of 

the Pacific basin (Wilson, 1963; Morgan, 1972).

In the summer of 1965, two holes were drilled on 

Midway atoll under the sponsorship of the Hawaii 

Institute of Geophysics, with financial support from 

the National Science Foundation. One hole was 

drilled on Sand Island (fig. 1) and penetrated 157 m 

(metres) of sedimentary rock before reaching 

basalt. The second hole was placed about 6.5 km to

the northeast, just behind the reef at the north end 

of the atoll. It was drilled from a barge resting on 

the lagoon floor and penetrated 385 m of sedimentary 

rock above a basalt basement. Sampling began at 

about 9 m in the Sand Island hole and at 21 m in 

the reef hole and continued to basement; recovery 

was 72 and 92 percent, respectively. Most of the 

samples were cores, but in a few short intervals 

only cuttings were recovered. Limestones are dominant, with minor amounts of tuffaceous limestones, 

clays, and marls. A summary of the rock types 

found is shown above the species charts for each of 

the holes (figs. 2 and 3), and a detailed account of 

the drilling operation and general geology of the 

cores can be found in Ladd, Tracey, and Gross 

(1970).

KILOMETRE5

CONTOURS IN FATHOMS

FIGURE 1. Midway atoll, showing location of drill holes. S, 

Sand Island hole; R, reef hole. From Ladd, Tracey, and 

Gross (1970).

Fl
F2 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

SAMPLES 

LITHOLOGY

DEPTH 

(metres)

Jugosocythereis lactea (Brady)_ 

Loxoconcha longispina Key ______

Xestoleberis sp. cf. X. curia (Brady). 

Neonesidea gierloffi (Hartmann) _ _. 

Triebelina bradyi Triebel* _______

Xestoleberis tumefacta Brady__________________

Neonesidea kauaiensis (Holden) _______________

Bairdoppilata sp.aff. B.bradyi (Bold)____________

Macrocypris"!sv. aff. Ml dimorpha Hazel and Holden. 

Paracypris franquesi Howe and Chambers ________

Jugosocythereis canaliculata n. sp., s.s 

Cletocythereis bradyi Holden* _____ 

Cyprideis beaconensis (LeRoy) 1 

Callistocythere crenata (Brady) _____ 

Loxoconcha uranouchiensis Ishizaki _ _

16. Lsp. It __________________________

17. Loxoconchella anomala (Brady) ___________

18. Cytherelloidea sp. 1*___________________

19. C. ? japonica Ishizaki_________________

20. Platycosta amicus n. sp ________________

21. Munseyella inconspicua (Brady)__________

22. Radimella convoluta (Brady)_____________

23. Bythoceratina sp *___________________

24. Aurila sp _________________________

25. Hermanites hawaiiensis n. sp ____________

26. Anchistrocheles sp *___________________

27. Potamocypris ? sp *__________________

28. Paradoxostoma sp. 1* __________________

29. Xestoleberis sp. cf. X. granulosa Brady __ ____

31. Macrocyprina gracilis (Brady) ___________

32. Jugosocythereis canaliculata reticulata n. subsp

33. Pokomyella pseudojaponica n. sp., s. s _______

34. P. pseudojaponica inflata n. subsp *_____.____

35. Semicytherura sp ____________________

36. Hemicytherura pentagona Hornibrook _______

37. Loxoconcha antillea Bold s.s _____________

38. Xestoleberis sp. 2_____________________

39. Radimella polycosta n. sp.,s. s ____________

40. Neonesidea sp. cf. N. simuvillosa (Swain) _____

41. N. ritugerda (Holden)_________________

42. Triebelina reticulopuncta Benson__________

43. Caudites spp _______________________

44. "Procythereis" northpacifica n. sp _________

45. Quadracythere trijugis n. sp _____________

46. Tenedocythere quadranodosa n. sp *________

47. Neocaudites terryi Holden*______________

48. Parakrithella robusta n. sp _____________

49. Loxoconchella honoluliensis (Brady) ________

50. L.sp*__ ______________ ________ __

51. Cytherella sp. 2_____________________

52. Cytherelloidea sp. cf. C. umbonata Edwards ___

53. C. sp. cf. C. umbonata Edwards var _________

54. Hermanites tschoppi (Bold) _____________

55. Triebelina crumena (Stephenson) _________

56. Bythocypris ? , compressa Brady _________

57. B. reniformis Brady ___________________

58. Jugosocythereis pannosa (Brady)__________

59. Hermanites sp. aff. H. barri Bold __________

60. Calliatocythere sp. 1*__________________

61. Xestoleberis sp. !_____________________

62. "Hemicythere" gordoni Bold _____________

63. Aurila sp. aff. A. lincolnensis (LeRoy) ______

ASSj

ASSEMBLAG

FIGURE 2. (See facing page for explanation.)
LATE CENOZOIC OSTRACODA F3

EXPLANATION 

Samples

Core Cuttings 

Lithologies

Limestone Clay or silt

Basalt

Checklist

Ostracodes 

missing

So

Sand Island-hole faunas

X 

Present

C

Common

A 

Abundant

Species occurring only in 

Sand Island hole

FIGURE 2. Species checklist for the Sand Island hole.

The ostracodes from the two holes are usually well 

preserved. In approximately 50 percent of the Sand 

Island cores and 25 percent of the reef hole cores, 

ostracodes were either lacking or so poorly preserved that they were not extracted. At several 

levels in both holes, ostracodes are very abundant, 

numbering scores of individuals per sample.

A total of 115 taxa are treated here, of which 25 

are described as new species, 10 as new subspecies, 

and 50 are described under open nomenclature. Most 

are shallow-water forms. In none of the sections 

where ostracodes occur is there a fauna that could 

be considered representative of deep water, that is, 

deeper than about 100 m.

Acknowledgments. Most of the work on the 

ostracodes was done at the National Oceanographic 

and Atmospheric Administration (NOAA) , Atlantic 

Oceanographic and Meteorological Laboratories, 

Miami, Fla., during 1971 and 1972. To the laboratory and to my supervisor, Robert S. Dietz, I wish 

to express my thanks. The ostracodes were supplied

by Harry S. Ladd and Joseph E. Hazel, who loaned 

the material from the Midway drill holes and supplied the photographs that compose plates 1-6. Without their cooperation this report would not have 

been possible. Rosalie Maddocks and Willem A. van 

den Bold have offered substantial assistance concerning various taxonomic problems. J. Wyatt Durham, Donald Hall, Joseph E. Hazel, and the late 

Nathan J. Ayer, Jr., critically read the manuscript 

and offered many helpful suggestions.

MAJOR ASSEMBLAGES

Interestingly, the stratigraphic distribution of the 

ostracodes in the reef and Sand Island holes is unlike 

that of the foraminifers studied by Todd and Low 

(1970). The ostracodes tend to be limited within the 

sections to distinct intervals. Sometimes this clustering is the result of evolutionary change, but for 

the most part it is probably the result of environmental preference. Whatever the cause, the ostracodes may be grouped roughly into three major assemblages within the two holes. Because the earliest 

assemblage is exclusively early Miocene, the reef 

hole has all three represented, whereas the Sand 

Island hole has only two. Though some of the taxa 

are erratic in their distribution patterns, being 

found in one hole and not in the other, most of the 

taxa within a given assemblage are found in both 

holes.

Assemblage L Most of the taxa here are either 

the same as or closely allied with living tropical 

Pacific species. The age is Pleistocene (?) and postMiocene on the basis of the known ranges of Cyprideis beaconensis, Radimella convoluta, and foraminiferal data (Todd and Low, 1970; Cole, 1969). 

The assemblage is more diverse in the Sand Island 

hole, which contains 31 taxa, of which 11 are found 

only there. The same assemblage in the reef hole 

numbers 19 taxa, of which 14 are also found in the 

Sand Island hole. Typical constituents are:

Neonesidea kauaiensis (Holden) 

Bairdoppilata sp. aff. B. bradyi (Bold) 

Loxoconcha longispina Keij 

Neonesidea gierloffi (Hartmann) 

Loxoconcha uranouchiensis Ishizaki 

Xestoleberis sp. cf. X. granulosa Brady 

X. sp. cf. X. curia Brady 

Jugosocythereis canaliculata n. sp.

Assemblage II. The interval from 150 to 250 m 

in the reef hole and 135 to 155 m in the Sand Island 

hole is distinct from the preceding assemblage and 

shares several taxa with the older assemblage III. 

It is late Miocene in the Sand Island hole and early 

and late Miocene in the reef hole (age based on the
F4 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

SAMPLES

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2. Bairdoppilata sp .aff. B. bradyi (Bold)

3. Jugosocythereis canaliculata n. sp., s. s ____________

5. Xestoleberis sp. cf . X. granulosa Brady ____________

6. Triebelina hanaumaensis( Holden)* 

7. Macrocyprina gracilis (Brady) 

8. Caudites spp 

9. Jugosocythereis lactea (Brady) 

10. Loxoconchella anomala (Brady)

11. Xestoleberis sp. cf. X. curta (Brady) 

12. Paradoxostoma romei McKenzie *

13. Neonesidea ritugerda (Holden) 

14. Xestoleberis tumefacta Brady 

15. Radimella convoluta (Brady)

16. Neonesidea gierloffi (Hartmann) 

17. Xestoleberis sp. 2 

18. Jugosocythereis canaliculata reticulata n. subsp _____ 

19. Loxoconcha uranouchiensis Ishizaki 

20. Munseyella inconspicua (Brady) ________________

21. "Procythereis" northpacifica n. sp

23. Loxoconchella honoluliensis (Brady) _____________ 

24. Pokornyella pseudo japonic a n. sp., s. s 

25. Xestoleberis sp. 1

26. Radimella polycosta n. sp., s. s.

27. Neonesidea sp. cf. N simuvillosa (Swain) 

28. Hermanites tschoppi (Bold) 

29. Loxoconcha antillea Bold s. s 

30. Neonesidea sc/mfe*(Hartmann) *____________---_

31. Triebelina sp. 1*

32. T. sp. 2* 

33. Bythocypris reniformis Brady 

34. Macrocypris ? sp. aff. M." dimorpha Hazel and Holden 

35. Pellucistoma sp*

37. Cytherelloidea sp. cf . C.umbonata Edwards var ______ 

38. Hemicytherura pentagona Hornibrook ____________ 

39. Havanardia sp. 3* 

40. Parakrithella eopacifica n.sp* -----------------

41. Pokornyella deformis (Reuss) ? *

42. Hermanites hawaiianensis n. sp

44. Triebelina reticulopuncta Benson _______________

45. Paranesidea sp. 2*

46. Bairdoppilata planolata planolata n. subsp * 

47. Paracypris sp. cf . P. rosefieldensis Howe and Law* 

48. Hammatocythere ? sebastianensis (Bold) 

49. Occultocythereis sp * 

50. Cytherella sp. 2

52. Cytherelloidea semipunctata n. sp *______________ 

53. Xestoleberis datelinensis n. sp * 

54. Pontocyprella ? sp. 1 

55. Platycosta amicus n. sp

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FIGURE 3. Species checklist for the reef hole.

is a New Zealand-Japanese species (Hornibrook, 

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LATE CENOZOIC OSTRACODA F5

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SAMPLES 

LITHOLOGY

8 DEPTH 

"* (metres)

(For numbers 56-99 see following pages.)

brook, and Xestoleberis sp. 1. In addition to these, 

the species Hermanites tschoppi (Bold) Radimella 

polycosta n. sp., Loxoconchella honoluluensis 

(Brady), and Bythocypris reniformis Brady are 

common to both assemblages II and III.

Assemblage III. The earliest assemblage is exclusively early Miocene (age based on foraminifers 

and ostracodes) and is present only in the reef hole 

from 283 m to the base of the fossiliferous section 

at about 362 m. It is composed of four distinct
F6 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

SAMPLES 

LITHOLOGY

DEPTH 

(metres) °

56. Cytherella sp. !*__________________________ 

57. Triebelina crumena (Stephenson) _______________ 

58. Cytherelloidea sp. cf . C. umbonata Edwards ____ ____ 

59. Quadracythere trijugis n. sp __________________ 

60. Bairdoppilata planolata ventrocaudata n. subsp _____

61. Tenedocythere turda n. sp *

62. T. setigera n. sp *__________________________ 

63. Neonesidea spica n. sp *_____________________ 

64. "Hemicy there'' gordoni Bold __________________ 

65. Aurila sp. aff. A. lincolnensis (LeRoy) ____________

66. Muellerina ? sp *_________________________ 

67. Hermanites praehawaiianensis n. sp *____________ 

68. Neocaudites sp *__________________________ 

69. Bairdoppilata planolata magnumcaudata n. subsp * _ _ _

70. Loxoconcha antillea Bold diffusia n. subsp *________ 

71. Cytherelloidea sp. 2* _______________________ 

72. Bythocypris ? compressa Brady _____________ ____ 

73. Paracypris franguesi Howe and Chambers- ________ 

74. Agliocypris sp *__________________________

75. Pontocyprella? sp. 2* ---------------------- 

76. Ostracode sp *______________-___--_------_ 

77. Semicytherura sp ________________-----_--_ 

78. Paracytheridea sp *________________-_---_--

79. Callistocythere crenata (Brady) ________________ 

80. C. sp. 2*______ _ _____________________ __

81. Paradoxostoma sp. 2*_ _______________________ 

82. Xestoleberis sp. cf. X. briggsi McKenzie* __________ 

83. "Cythere " sp. cf. "C" caudata Brady* ____________

84. Neonesidea sp. aff. N. cassida ( Bold) *____________ 

85. Quadracythere aequabilis n. sp *________________ 

86. Neonesidea sp. 3* __________________________ 

87. Jugosocythereis pannosa (Brady) ________________ 

88. Havanardia 1 cuneolus n. sp *_________________

89. Orionina flabellacosta n. sp* _________________ 

90. Neonesidea sp. !*__________________________ 

91. AT.sp.2*________________________________ 

92. Paranesidea handeli n. sp *___________________ 

93. P. sp.l* __________ _ ____________________

94. P. victrix (Brady)*

95. Havanardia sp. !*_________________________ 

96. Hermanites sp. aff. H. barri Bold_ _______________ 

97. Neonesidea ? reefholensis n. sp *_______________ 

98. Loxoconcha sp. 2* _________________________ 

99. Quadracythere spica n. sp *___________________

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EXPLANATION 

Samples

Core Cuttings

D

Unlithified sediment Partially Limestone 

lithified sediment

X C

Present Common

Lithologies

Dolomite

Checklist

Clay or silt Conglomerate

A

Abundant Ostracodes 

missing

Reef-hole faunas Species occurring 

only in reef hole

FIGURE 3. Continued.
LATE CENOZOIC OSTRACODA F7

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faunas, each of which contains 25-30 species. It has 

strong Caribbean geographic affinities, including:

Triebelina crumena (Stephenson) 

T. reticulopuncta Benson 

"Hemicythere" gordoni Bold 

Paracypris franquesi Howe and Chambers 

Pokornyella deformis ( Reuss) ? 

Hammatocytheret sebastianensis (Bold) 

Neonesidea sp. cf. N. cassida (Bold) 

Jugosocythereis pannosa (Brady) 

Cytherelloidea sp. cf. C. umbonata Edwards 

Hermanites tschoppi (Bold)

The last five species are among some of the most 

abundant species in this section. The other species

that define assemblage III are:

Paracypris sp. cf. P. rosefieldensis Howe and Law 

Cytherella textum n. sp. 

Xestoleberis datelinensis n. sp. 

Tenedocythere setigera n. sp. 

Hermanites praehawaiianensis n. sp. 

ParaJcrithella eopacifica n. sp.

THE FAUNAS 

REEF HOLE

Fauna Rt . Sampling in the reef hole began at 21 

m. From this level to almost 130 m, with faunal
F8 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

breaks from 31.5 to 56.2 m and 104.9 to 123.8 m, 

the section contains a bairdiid-rich fauna that has 

tropical Pacific characteristics.

Fauna R2 . The interval between 96.0 and 101.8 

m contains no bairdiids, which is anomalous, for in 

material that is highly recrystallized, the larger 

ostracodes are usually better preserved than the 

smaller forms. This interval contains only species 

of Loxoconcha and Xestoleberis and a different subspecies of Jugosocythereis canaliculata than occurs 

in fauna Rj.

Fauna R3 . No ostracodes were available from 130 

to 151 m and an unconformity is present at about 

149 m (Ladd and others, 1970). At 151 m an abrupt 

change in the fauna occurs; only three of the 20 

taxa from the shallower interval recur. This fauna 

is dominated by "Procythereis" northpacifica, Parakrithella robusta, Hermanites tschoppi, Loxoconcha 

antillea, and Bythocypris reniformis. There is some 

evidence to indicate that the fauna represents a 

deeper or cooler water environment, or both, than 

the previous ones. "Procythereis" northpacifica is 

closely related to an undescribed species from Bass 

Strait, southern Australia, and Parakrithella robusta and Pokornyella pseudojaponica are related to 

southern Japanese species. In addition, the genus 

Cytherelloidea is completely missing from fauna R3 , 

but is abundant in the more diversified but contemporaneous fauna SH in the Sand Island hole. According to Sohn (1962), the great majority of species in this genus are known from depths shallower 

than 92 m.

Fauna R4 . The brief interval between 172 and 

173 m contains great abundance of Parakrithella 

robusta and the only occurrence of Radimella polycosta rugosa, a subspecies with heavily calcified 

lateral ridges. It is also the only interval in assemblage II where the genus Cytherelloidea is found. 

Except for containing fewer taxa, fauna R4 is much 

like the late Miocene fauna Sr, in the Sand Island 

hole.

Fauna R5 . Another brief interval between about 

243 and 246 m contains only four species, but all 

of them are bairdiids, indicating a shallower and 

(or) warmer environment than faunas R3 or R4 . 

Triebelina hanaumensis Holden, which is a shallow-water species now living in Hanauma Bay, 

Hawaii (Holden, 1967), occurs only there and in 

fauna R± . Just above the section containing this 

fauna is a sparsely fossiliferous one from about interval 120 to 135 m containing Radimella polycosta 

and a species of Havanardia. These species are not 

assigned to a fauna.

The third major assemblage contains four recognizable faunas on the basis of the occurrences and 

abundances of their constituents and first appears 

at about 283 m with the diverse and abundant fauna 

R6 .

Fauna Rc . Besides the typical assemblage III 

species, the following taxa are found only here:

Havanardia sp. 2

Cytherella sp. 2

Cytherella sp. 1

Quadracythere trijugis n. sp.

"Hemicythere" gordoni Bold

Muellerma! sp.

Neocaudites sp.

Bairdoppilata planolata n. sp. magnumcaudata n. subsp.

Fauna R7 . A very brief interval between 317.37 

and 318.82 m beneath fauna R6 contains a great 

abundance of Hammatocy there? sebastianensis 

(Bold) along with several species from fauna R6 . 

Hammatocythere is similar in shape and ornamentation to the genus Patagonacythere. Living species of 

that genus are known only from high latitudes; 

hence, fauna R7 may be indicative of relatively cool 

conditions. In support of cooling conditions (cool 

temperate?) is the common occurrence of Bythocypris reniformis Brady, a deep- or cool-water species of the present Pacific (Brady, 1880), and the 

general lack of bairdiids. Only one bairdiid species 

appears in this diverse fauna two specimens of 

Paranesidea sp. 2 at 317.37 m.

Fauna R,. The interval beneath that of fauna R7 , 

between about 320 to 324 m, is considered tropical. 

The three bairdiid species, Triebelina reticulopuncta, 

Neonesidea spica, and N. sp. cf. N. cassida, though 

not common, are consistently present in the samples in this interval. Hammatocytherel sebastianensis, so common in fauna R7 , is completely absent 

here. Species that are peculiar to the fauna include:

Semicytherura sp.

Paracytheridea sp.

Callistocythere sp. 2

Paradoxostoma sp. 2

Xestoleberis sp. cf. X. briggsi McKenzie

Neonesidea sp. aff. N. cassida (Bold)

Callistocythere crenata, also present in fauna Si 

(post-Miocene) in the Sand Island hole, recurs in 

fauna R8 .

Fauna R9 . The earliest fauna is characterized by 

the absence of many of the later assemblage III species and by the presence of several species whose 

duration in the area was apparently short. Among 

the later, Orionina flabellacosta, Havanardia sp. 1, 

and Paranesidea handeli dominate. Of the 34 taxa, 

12 are bairdiid species whose diversity and abundance indicate a tropical environment.
LATE CENOZOIC OSTRACODA F9

SAND ISLAND HOLE

Assemblage I in the Sand Island hole is more 

diverse and is composed of more faunas than it is 

in the reef hole. Each fauna is separated by a sometimes large unfossiliferous interval. Smaller foraminifers are equally sparse (Todd and Low, 1970). 

These barren intervals may represent long time 

spans and slow rates of deposition resulting from 

lower sea-level stands. However, other factors may 

be responsible, such as postdepositional erosion or 

slow rates of deposition because of low biological 

productivity.

Fauna Si. Ostracodes are very rare from 9 to 

20 m, though well preserved. The fauna is characterized mostly by the lack of the common and 

abundant elements in other assemblage I faunas, 

with the exception of Triebelina bradyi Triebel, 

which is found only here.

Fauna S2 . From 42 to 46 m most of the specimens are young individuals, possibly indicating redeposition of the smaller valves. Preservation, however, is very good and the redeposition, if such was 

the case, was probably from contemporary nearby 

sites. Two adult individuals of Cyprideis beaconensis 

(LeRoy) show that here, or nearby, the water was 

probably brackish. The fauna is a diverse one, containing 19 species, of which Xestoleberis tumefacta 

and Neonesidea kauaiensis (Holden) are the most 

abundant.

Fauna S3 . From 73 to 79 m the brackish-water 

Cyprideis beaconensis (LeRoy) dominates, though 

the significant numbers of other normal marine 

ostracodes suggest that these others were living in 

the same area, especially Xestoleberis sp. cf. X. curta 

(which has here replaced the abundant X. tumefacta 

of fauna S2 ) and Loxoconcha longispina. Concerning 

the environment of this fauna, the discussion by 

Resig (1969), p. 26) on the Pleistocene Cyprideis 

beaconensis fauna of Hawaii is pertinent:

The frequent association of Loxoconcha and Xestoleberis with 

Cyprideis in the Ewa material has its counterpart in Recent 

assemblages of inner Pearl Harbor and Kaneohe Bay. This 

environment (is) characterized by salinity reduction of limited 

duration and dependent upon rainfall***"

Cyprideis beaconensis occurs in great abundance 

only at two levels, 73.91 and 78.88 m. Elsewhere it 

is represented by a few to several, mostly young 

valves. Considering these data, it is unlikely that 

the lagoon was entirely enclosed and freshened as 

is the case today at Clipperton Island (Allison and 

Holden, 1971).

Fauna S4 . Ostracodes are extremely abundant 

between 85.19 and about 88 m. From the outset to 

the end of the fossiliferous section at 97.84 m,

Jugosocythereis canaliculata reticulata is in great 

abundance. Toward the bottom of the section only 

this species and abundant Loxoconcha uranouchiensis are present. Throughout the interval, ostracode 

diversity is low, and bairdiids are rare and occur 

only in the upper part.

Fauna S5 . Ostracodes are missing, or were not 

picked, presumably because they were too rare, 

through a thick section extending from about 98 to 

136 m. Smaller foraminifers do occur, however, 

Amphistegina madagascarensis and miliolid fragments predominating (Todd and Low, 1970). A 

coarse conglomerate of basaltic cobbles occurs between 130 and 135 m and at the lower depth A. 

madagascarensis is last found. Deeper than about 

136 m most of the samples contain sparse to abundant ostracodes, all representing a single diverse 

fauna dominated by abundant Parakrithella robusta, 

Pokornyella pseudojaponica, and common Hermanites tschoppi (Bold) and Loxoconcha antillea Bold.

CORRELATION

Figures 2 and 3 show the distribution and abundance of the taxa in the Sand Island and reef holes, 

respectively. The taxa are arranged in order of their 

first occurrences, allowing them to be grouped into 

their faunas and assemblages, which are noted with 

the same symbols used in the text. Those marked 

with an asterisk occur only in that hole. The taxa 

are numbered consecutively; these numbers also appear in the text under the species descriptions to 

facilitate locating each on the charts.

Major assemblages I and II afford good general 

correlations between the Sand Island and reef holes. 

In both holes, unfortunately, a large unfossiliferous 

section divides assemblages I and II. This paleontological gap may represent all of Pliocene time.

In assemblage I, fauna Rx (21-96 m) and faunas 

S2 and S3 (42-78 m) both contain Radimella convoluta, and R2 (96-102 m) and S4 (85-98 m) both 

contain Jugosocythereis canaliculata reticulata. 

These taxa are restricted to these faunas and are 

interpreted as being contemporaneous. As fauna R2 

begins at 96 m and S3 ends at 78 m, this level in 

the reef hole represents an 18-m greater water depth 

than that in the 'Sand Island hole.

In the late Miocene assemblage II, faunas R3 and 

R t (151-173 m) collectively correlate well with 

fauna >Sr, (136-152 m). The taxa restricted to and 

shared by these faunas include Parakrithella robusta, "Procythereis" northpacifica, Xestoleberis sp. 

1, Cytherelloidea sp. cf. C. umbonata variation, and 

Hemicytherura pentagona Hornibrook. The differ-
F10 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

ences between first and last occurrences of these 

taxa in the two holes averages about 15 m, again 

the interval in the reef hole being the deeper.

AGE

Three lines of evidence point to a possible Pleistocene age (noted herein as "Pleistocene?") assignment for the sediments down to about 95 m in the 

reef hole and 80 m in the Sand Island hole. The first 

of these involves the abnormal composition of some 

of the faunas, namely fauna R2 of the reef hole and 

S4 of the Sand Island hole. These faunas, so far as 

is known, have no counterparts in modern tropical 

reef or lagoonal faunas, but the literature describing the ostracode assemblages from these environments is insufficient to verify this fact. These assemblages are characterized by their lack of bairdiid 

ostracodes and contain the distinctive subspecies 

Jugosocythereis canaliculata reticulata, which only 

occurs in these faunas. These faunas are inferred to 

represent cooler water than those immediately superadjacent and subadjacent. The presence of Loxoconcha uranouchiensis Ishizaki within fauna R2 and 

its abundance in fauna S t support this interpretation. This species is living today in bays of northern 

and southern Honshu, Japan.

Secondly, Radimella convohita which is found in 

faunas S2 and S3 in the Sand Island hole, and the 

correlative fauna R! of the reef hole, is known from 

the Pleistocene of Oahu, Hawaiian Islands (Resig, 

1969).

Thirdly, Cyprideis beaconensis (LeRoy) of faunas 

S2 and S3 is known only from the Pleistocene to 

Holocene, though its geographic distribution is quite 

wide (Sandberg, 1964).

The early and late Miocene age of the sediments 

in the Midway cores is based on the study of the 

Foraminifera. According to Todd and Low (1970), 

who studied the smaller foraminifers, upper Miocene (Tertiary g) is first found at 136 m in the Sand 

Island hole and 153 m in the reef hole. Lower Miocene is reached at 278 m in the reef hole. Cole 

(1969), in his studies of the larger foraminifers, 

recognized lower Miocene (Tertiary e) at 180 m in 

the reef hole.

Macrocyprisl sp. aff. M.I dimorpha Hazel and 

Holden from Tonga (Hazel and Holden, 1971) is an 

Eocene species. The Pleistocene (?) to early Miocene 

Midway form is closely related to it. Another long-- 

ranging species, Jugosocythereis pannosa, is late 

Eocene to Holocene in the gulf coast-Caribbean region. It occurs in the lower Miocene of the reef 

hole and upper Miocene of the Sand Island hole.

Several assemblage III species that are relatively short-ranging in the Caribbean-gulf coast region 

offer an age determination for the lower stratigraphic interval in the reef hole below about 280 

m. All these species extend back into the Oligocene, 

or Oligocene-Miocene (where there is doubt about 

the boundary), except for Pokornyella deformis 

Reuss?, which appears to be confined to lower to 

middle Miocene rocks in the Caribbean (Bold, 

1966b). These species are:

Paracypris rosefieldensis (Oligocene-Miocene) 

Loxoconcha antillea (early Miocene) 

Hermanites tschoppi (early to middle Miocene) 

"Hemicythere" gordoni (Oligocene-Miocene)

Hammatocythere ? sebastianensis (Bold, which is 

the major constituent of fauna R7 and which commonly occurs throughout fauna R6 , is otherwise 

known only from the Oligocene of Puerto Rico 

(Bold, 1965). Also occurring only in the rocks of 

this stratigraphically short interval is Paracypris 

franquesi known from the Caribbean Eocene and 

Oligocene. These species, together with Neonesidea 

sp. aff. N. cassida, which bears a resemblance to 

Bairdia cassida Bold from the Oligocene of Cuba, 

suggest that the lower part of the reef hole may 

correlate with the Caribbean Oligocene. This correspondence cannot be definitely asserted, however, 

as these species occur with the Miocene Pokornyella 

deformis. Because of this discrepancy and because 

of the foraminiferal ages assigned by Todd and Low 

(1970), and by Cole (1969), an early Miocene age is 

favored.

BIOGEOGRAPHIC AFFINITIES OF THE FAUNAS

Cole (1969) presented a strong argument for a 

westward migration, to Midway from the Indopacific region, of the larger Foraminifera accompanying the ostracode faunas. All the larger Foraminifera, including both the fossil and Holocene, 

are Indopacific species.

The early Miocene assemblage III ostracode 

faunas contain several species known only from the 

Caribbean. Some of these also occur in the late 

Miocene assemblage II in both holes. Why the ostracode faunas have affinities to the Caribbean whereas 

the other invertebrates do not is an intriguing problem. Unfortunately, Miocene or earlier Tertiary 

ostracodes have not previously been described from 

the tropical insular Pacific. The Ostracoda described 

from the Funafuti drill holes were originally believed to be as old as Miocene (Chapman, 1914) but 

are now known to be Pleistocene to Holocene (Ladd 

and others, 1970). The sparse literature from the
LATE CENOZOIC OSTRACODA Fll

East Indies, including the works of Kingma (1948), 

LeRoy (1939, 1941), Fyan (1916), and Guha 

(1968), and from India, including Guha (1965a, b), 

indicate no biogeographic connection between these 

areas and Midway during the Miocene.

To date, about 65 Holocene ostracode species have 

been described from the "Pacific Realm" of Benson 

(1964), encompassing the open Pacific islands (excluding the East Indies, Funafuti, Samoa, Fiji, New 

Caledonia, and New Zealand, which are considered 

part of the "Indopacific Realm" by Benson). In the 

Caribbean (excluding the Gulf of Mexico region) 

perhaps as many as 130 species have been described. 

Apart from the Clipperton Island fauna containing six Caribbean ostracode species, only one other 

shallow-water species is known to be shared between these provinces Munseyella inconspicua, 

(Brady) (Teeter, 1966). Hence, it appears that the 

present Pacific ostracode faunas have little in common with those of the Caribbean, but in the Miocene 

a distinct connection existed between these two regions.

Allison and Holden (1971) noted the Caribbean 

affinities of Holocene Clipperton Island ostracodes 

and suggested that during the time that middle 

America was a seaway, surface currents swept out 

from east to west, as do the North Atlantic and 

North Pacific Equatorial currents today. This circulation pattern also could explain the Caribbean 

affinities of some of the elements in assemblages II 

and III. Regardless of whether the species migrated 

east to west or vice versa, it appears clear that a 

biogeographic connection existed.

Some affinities to Japan and Okinawa are noted 

in that the genus Parakrithella is known previously 

only from that area. Because in Asia the genus is 

Pliocene to Holocene and in Midway it is early Miocene to post-Miocene, it would appear that migration was from east to west. A somewhat clearer 

Japanese influence is seen in the late Miocene assemblage II and post-Miocene assemblage I with 

the introduction of Pokornyella pseudojaponica, 

Loxoconcha uranouchiensis, and Cytherelloideal 

japonica. Probably these and many other species 

made their way to the atoll via the Kuroshio Current.

SYSTEMATIC PALEONTOLOGY

In the following pages, stratigraphic horizon 

designations include the abbreviations "R" and "S" 

for the reef and Sand Island holes, respectively. For 

example, S-140.21 m indicates a depth of 140.21 m 

in the Sand Island hole. KR and MR stand for

Kure atoll lagoon and Midway lagoon, respectively. 

RV signifies right valve, LV, left valve. L stands for 

length, H for height, and W for width. Under the 

heading "Distribution" the number of specimens 

found is recorded in parentheses. The number in 

parentheses under "Species No." refers to the checklists (figs. 2, 3). All figured types have been deposited at the U.S. National Museum (Natural History) (USNM), Washington, D.C. Some secondary 

types are at the Museum of Paleontology, University of California, Berkeley (UCB). All measurements are in microns.

Subclass OSTRACODA Latreille, 1806

Order PODOCOPIDA Muller, 1894

Suborder PODOCOPINA Sars, 1865

Superfamily BAIRDIACEA Sars, 1888

Family BAIRD1IDAE Sars, 1888

Subfamily BAIRDIINAE Sars, 1888

Genus NEONESIDEA Maddocks, 1969

Neonesidea gierloffi (Hartmann)

Plate 7, figure 1

Bairdia crosskeiana Brady. Brady, 1880, Kept. * * * Voyage * * * Challenger, Zoology, v. 1, p. 58, pi. 9, figs. 

3a-c.

Holden, 1967, Pacific Sci., v. 21, no. 1, p. 12, 13, textfigs. 3h-l. 

Not Brady, 1866, Zool. Soc. London Trans., v. 5, p. 366,

pi. 57, figs. lOa-d. 

Triebelina gierloffi Hartmann, 1959, Kieler Meeresforschungen,

v. 15, no. 2, p. 214-217.

Type and dimensions. Hypotype USNM 184298. 

Adult RV. S-44.20 m. L=758, #=383, W=15Q.

Distribution. Pleistocene (?): Sand Island hole 

(6), reef hole (5); Post-Miocene: reef hole (2). 

Species No. S(4),R(16).

Discussion. The forms dealt with by Brady 

(1880) and Holden (1967) under Bairdia crosskeiana are conspecific with Neonesidea gierloffi. 

Bairdia crosskeiana of Brady (1866) from the Levant (eastern Mediterranean) is distinct. Brady's 

(1866) original description is brief, but his illustrations show a species much higher in side view and 

more centrally inflated, as seen from above, than 

any of those so far reported from the Pacific.

The species is living widespread in the Pacific. It 

is found in the Admiralty Islands north of New 

Guinea at 32 m (Brady, 1880), off Hawaii at 44 m 

(Holden, 1967) to 80 m (Brady, 1880), and off El 

Salvador at 2-12 m (Hartmann, 1959).

Neonesidea sp. aff. N. cassida (Bold)

Plate 7, figures 2-4

Types and dimensions. 

Specimen

USNM 184299. 

Specimen

USNM 184300. 

Specimen

USNM 184301. 

Specimen

UCB 40504.

Depth (m) L H W

Adult carapace _____ ..R-320.95 800 452 364

Adult carapace ______R-321.72 858 490 393

Adult carapace ______R-321.72 850 502 373

Adult carapace ______ R-321.87 884 498 396
F12 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Specimen

USNM 184302. 

Specimen

USNM 184303.

Distribution. Lower Miocene: reef hole (11).

Species No. R (84).

Discussion. This species is like the Cuban Oligocene Neonesidea cassida (Bold, 1946), but is much 

smaller, is relatively wider, and has a blunter anterior margin. Its range at Midway was short, 

between R-320.64 m and R-321.86 m.

Neonesidea sp. cf. N. simuvillosa (Swain) 

Plate 7, figures 5-8

Types and dimensions. 

Depth (m) L H W

Adult carapace ____..S-147.37 873 473 385

Adult RV __________S-147.37 900 440 170

Distribution. Lower Miocene: reef hole (1). 

Upper Miocene: reef hole (1) ; Sand Island (6).

Species A/o. S(40), R(27).

Discussion. The species has the general morphology of Neonesidea simuvillosa from the west coast 

of Mexico (Swain, 1967) and Clipperton Island 

(Allison and Holden, 1971), but it has a higher anterior margin and is serrated along the posteroventral margin; because of these differences it cannot 

be definitely assigned to N. simuvillosa. Benson's 

(1959) "Bairdia sp.," included by Swain in the 

synonomy of N. simuvillosa, was compared with 

Neonesidea verdesensis (LeRoy) ; "Bairdia sp." 

primarily differs from N. verdesensis by lacking 

posteroventral serrations. Despite the presence of 

serrations on N. verdesensis and its implied similarity to N. simuvillosa, specimens of N. verdesensis 

from San Diego or San Pedro (Timms Point Silt 

Member) and Santa Barbara Formations of southern California observed by the writer do not resemble the Midway specimens.

Neonesidea ritugerda (Holden)

Bairdia ritugerda Holden, 1967, Pacific Sci., v. 21, no. 1, p. 

12, 13, figs. 6a-g.

Diagnosis. See Holden (1967). 

Types and dimensions. 

Hypotype

USNM 184304. 

Hypotype

UCB 40505.

Depth (m) L H W

Adult LV __._____R-67.67 964 529 285

Adult LV ________R-78.33 1045 623 302

Distribution. Upper Miocene: reef hole (3) ; 

Sand Island hole (1). Post-Miocene: reef hole (3).

Species No. S (41), R(13).

Discussion. The Midway specimens are nearly 

identical with Neonesidea ritugerda, a late Cenozoic 

fossil from submerged terraces in the Hawaiian 

Islands.

Neonesidea schulzi (Hartmann)

Plate 7, figures 9-11

Triebelina schulzi Hartmann, 1964, Kieler Meeresforschungen, 

v. 20, p. 44-46, pis. 4, 5: figs. 14-22.

Haddocks, 1969, U.S. Natl. Mus. Bull. 295, p. 20-24, figs.

4a-m, 5, 6. 

Species BA, Haddocks, 1966, Kansas Univ. Paleont.

Contr., Paper 12, p. 47, fig. 22.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184305. Adult carapace R-295.05 972 542 450 

Hypotype

UCB 40506. Young carapace - R-183.46 816 469 372

Distribution. Lower Miocene: reef hole (66). 

Upper Miocene: reef hole (6).

Species No. R(30).

Discussion. The species is found only in the reef 

hole between R-295.81 m and R-161.24 m. These 

specimens are more streamlined than those figured 

by Maddocks (1969) from Nosy Be, Madagascar, 

and by Hartmann (1964) from El Salvador, but 

otherwise appear morphologically assignable to the 

species.

Neonesidea kauaiensis (Holden) 

Figure 4

Bairdia amygdaloides Brady, 1880, Kept. * * * Voyage * * * 

Challenger, Zoology, v. 1, p. 54-55, pi. 9, figs. 5a-f.

Bairdia kauaiensis Holden, 1967, Pacific Sci., v. 21, no. 1, p. 

8-11, text-figs. 3a-i.

Types and dimensions. 

Depth (m) L H W

Adult LV ______. S-45.11 1049 648 288

AduJt LV _________S-45.11 1145 704 334

Adult LV ___--_____S-44.20 1095 63? 295

Penultimate LV _____S-45.11 865 507 236

3d from last instar ___S-45.11 624 362 249

4th from last instar __S-45.11 494 249 118

5th from last instar _S-45.11 411 250 115

Hypotype

UCB 40507. 

Hypotype

UCB 40508. 

Hypotype

USNM 184306. 

Hypotype

USNM 184307. 

Hypotype

USNM 184308. 

Hypotype

USNM 184309. 

Hypotype

USNM 184310.

Distribution. Pleistocene (?) : Sand Island hole 

(109); reef hole (25). Post-Miocene: Sand Island 

hole (50) ; reef hole (11).

Species No. S(7), R(l).

Discussion. Brady (1880, p. 54) described the 

surface as "smooth, often finely punctate." Puncta 

on the Midway specimens, as well as on those from 

Hawaii (Holden, 1967) can be seen only after staining. This invisible pitting places the taxon in Neonesidea. General carapace shape and nature of the adductor muscle-scar pattern confirm this generic assignment.

Neonesidea spica Holden, n. sp.

Plate 7, figures 12-14

Diagnosis. Carapace compressed, greatest width 

in anterior half; caudal process dorsally humped, 

with terminal spine on left valve; posteroventer 

serrate.

Description. Carapace terminally acuminate, 

smooth; posteroventer finely serrate in both valves;
LATE CENOZOIC OSTRACODA F13

700

600

500

400

300

200

o 8

IV

-ADULT300 400 500 600 700 800 900 1000 1100 1200

LENGTH

FIGURE 4. Length-height plot of Neonesidea kauaiensis (Holden) from Midway atoll. -Q- from R-22.25 m, 4" from R-31.55

m, o from S 45.11 m. Measurements in microns.

dimorphism pronounced, with females (inferred) 

higher (L/#=1.65±), males lower (L/#=1.78±). 

Caudal process distinctly humped dorsally. Lateral 

view: highest in anterior half; middorsum gently 

rounded, posterodorsum concave up, anterodorsum 

straight, venter flat to slightly rounded, posteroventer straight, anterior margin obliquely rounded 

tending to subtruncate. Dorsal view: asymmetrically lenticular; greatest width just anterior to midlength; extremities pointed.

Duplicature of moderate width; vestibules large. 

Other internal features not observed.

Types and dimensions. 

Holotype

USNM 184311. 

Paratype

USNM 184312. 

Paratype

USNM 184313. 

Paratype

UCB 40509.

Depth (m) L H W

Adult? carapace .. -R-320.95 958 541 416

Adultc? carapace ..R-338.25 1041 583 416

Adultc? RV ___....___R-338.48 1040 551 182

Adult? carapace ____R-338.12 1080 650 465

Distribution. Lower Miocene: reef hole (30).

Species No. R(63).

Discussion. The species is found only in the reef 

hole between R-343.30 m and R-295.20 m. In gross 

morphology, it closely resembles Neonesidea sp. cf. 

N. simuvillosa (Swain) of this report, which occurs 

stratigraphically higher in the reef hole and in the

upper Miocene of the Sand Island hole. The important differences between the two species are the 

lenticular carapace of N. spica and its more pronouncedly humped caudal process that terminates in 

a prominent spine. The similarity of the two forms 

and their stratigraphic relationship indicate that N. 

spica is probably the precursor of N. sp. cf. N. simuvillosa.

Neonesidea? reefholensis Holden, n. sp. 

Plate 8, figures 1-3

Diagnosis. Carapace bulbously inflated midventrally, width almost equal height; anterolateral and 

posterolateral surfaces somewhat compressed, giving concave appearance in dorsal view; dorsal margin highly arched.

Description. Carapace large, smooth, more than 

1,000 p long; heavy, highly inflated, greatest width 

midventrally. Lateral view: greatest height at midlength at arched middorsum, anterior and posterior 

cardinal angles indistinct; anterior margin obliquely subtruncate; ventral margin straight; posterior 

margin straight beneath somewhat upturned pointed 

caudal process. Dorsal view: bulbously inflated, anteriolateral and posterolateral surfaces gently concave out.
F14 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Duplicature of moderate width, vestibules well 

developed. Other internal features not observed. 

Types and dimensions. 

Holotype

USNM 184314. 

Paratype

USNM 184315. 

Paratype

UCB 40510.

Depth (m) L H W

Adult carapace _---R-343.30 1170 756 685

Adult RV __________R-341.53 1060 588 280

Adult carapace _____R-343.05 1085 643 590

Distribution. Lower Miocene: reef hole (34).

Species No. R (97).

Discussion. The species occurs only in fauna R9 

between R-343.30 m and R-341.52 m but is locally 

abundant. Except at the top of its known occurrence, at R-341.52 m, the species is always accompanied by Havanardia spp.

Neonesidea sp. 1

Plate 7, figures 15-17

Types and dimensions. 

Specimen

USNM 184316. 

Specimen

USNM 184317. 

Specimen

UCB 40511.

Depth (m)

Adult carapace _ -__--R-337.34 

Adult carapace ._____R-343.21 

Adult carapace _.____R-343.21

L H W

1113 729 553

1034 624 491

1022 616 486

Distribution. Lower Miocene: reef hole (3).

Species No. R(90).

Discussion. Of the three specimens known, the 

two from R-343.21 m are somewhat lower in height 

(L/H = 1.66) than the single individual from R337.34 m (L/H = 1.53). Whether this difference is 

caused by sexual dimorphism or genetic variation 

cannot be determined.

The shape of the species is quite distinctive. In 

lateral view, the low caudal process is posteriorly 

extended, thereby accentuating the dorsal hump on 

the caudal process; in dorsal view, the carapace is 

bulbously inflated.

Neonesidea sp. 2 

Plate 7, figures 20-22

Types and dimensions. 

Specimen

USNM 184318. 

Specimen

UCB 40512.

Depth (m) L H W

Adult carapace ..____R-336.56 1150 681 534

Adult LV __________R-336.27 1137 745 334

Distribution. Lower Miocene: reef hole (2).

Species No. R(91).

Discussion. The two specimens come from R336.27 m and R-336.56 m, indicating a brief existence for the species at Midway.

The presence of pits on the posterior lateral surfaces of both valves indicates that the species could 

have been assigned to Paranesidea; however, the 

pits are limited and very faint.

Neonesidea sp. 3

Plate 7, figures 18, 19 

Types and dimensions. 

Specimen

USNM 184319. 

Specimen

USNM 184320.

Depth (m) L H W

Adult RV _________R-321.41 853 453 170

Adult LV _______R-320.34 818 455 199

Distribution. Lower Miocene: reef hole (6).

Species No. R(86).

Discussion. Of the six individuals found, four 

appear to be young. All come from the reef hole 

between R-321.41 m and 320.34 m in fauna R8, indicating a very short existence at Midway Island.

Genus HAVANARDIA Pokorny

Havanardia? cuneolus Holden, n. sp.

Plate 1, figure 3; plate 8, figures 4, 5

Diagnosis. Densely pitted; heavy, each valve 

having a vertical median swelling; diamond shaped 

in dorsal outline.

Description. Covered with pits; shell heavy; 

median enlargement distinctive, consisting of a vertical wedge at midlength on each valve. Lateral 

view: overlap slight, middorsum flat, horizontal; 

anterodorsum and posterodorsum straight, sloping 

at same low angle; ventral margin concave down; 

anterior margin broadly rounded, posterior margin 

gently rounded, terminating in pointed caudal process at midheight, entire margin with 12 large projecting spines in left valve, shorter spines in right 

valve. Dorsal view: diamond shape; posterolateral 

and anterolateral surfaces flattened; extremities 

pointed; width equal to height.

Hinge smooth; duplicatures of moderate width, 

deep vestibules present.

Types and dimensions. 

Holotype

USNM 184321. 

Paratype

USNM 184322.

Depth (m) L H W

Adult carapace ______ R-342.90 883 528 566

Adult carapace ______ R-343.21 938 583 592

Distribution. Lower Miocene: reef hole (70).

Species No. R(88).

Discussion. The assignment of the species to 

Havanardia is made with some reservations. The 

venter is superficially flattened because of the ventrally extended enlargement, but it is not flattened as 

much as in other Havanardia. Quite possibly the 

taxon warrants a new genus, as no other bairdiids 

show this distinctive vertical midswelling.

Havanardia sp. 1

Plate 8, figures 6-8 

Types and dimensions. 

Specimen

USNM 184323. 

Specimen

USNM 184324. 

Specimen

UCB 40513.

Depth (m) L H W

Adult carapace _____R-343.30 1132 690 842

Broken adult carapace .R-343.30 -. 723 856

Adult RV _____--R-343.30 1200 643 469

Distribution. Lower Miocene: reef hole (3). 

Species No. R (95).
LATE CENOZOIC OSTRACODA F15

Discussion. The species is very rare, being found 

only at R-343.30 m. It is the earliest representative 

of a group of three Havanardia species, including 

H. sp. 2 and 3, that are considered closely related, 

though morphologically distinct and stratigraphically discontinuous in their distribution. Havanardia 

sp. 1 is the largest, is smooth, and has a distinct 

alar keel, whereas H. sp. 2 and 3 are smaller, 910 to 

950 fji., and lack the strong keel. Havanardia sp. 3 

is covered with small pits The observed distributions of all three species are limited, H. sp. 2 being 

at R-283.46 m and R-284.00 m and H. sp. 3 found 

only at R-224.03 m and R-231.65 m. The lateral 

and dorsal outlines of all three are nearly identical.

Havanardia sp. 2

Plate 8, figure 9

Types and dimensions. Specimen USNM 184325. 

Adult carapace. R-284.00 m. L=910, #=506, W= 

590.

Distribution. Lower Miocene: reef hole (2).

Species No. R(43).

Discussion. See Havanardia sp. 1 for a discussion of this species.

Havanardia sp. 3

Plate 8, figure 13

Types and dimensions. 

Specimen

USNM 184326. 

Specimen

UCB 40514.

Depth (m)

Adult carapace __-..____R-231.65 

Adult carapace _____R-224.03

L H W

922 519 522

950 539 556

Distribution. Lower Miocene: reef hole (2). 

Species No. R(39).

Discussion. See Havanardia sp. 1 for a discussion of this species.

Genus TRIEBELINA van den Bold, 1946 

Triebelina crumena (Stephenscn)

Plate 1, figures 5, 6

Bairdial crumena Stephenson, 1944, Jour. Paleontology, v. 18,

18, no. 2, p. 156, pi. 28, fig. 5. 

Triebelina cubensis Bold, 1946, Amsterdam, p. 74, pi. 5, figs.

4a-d. 

Glyptobairdia crumena (Stephenson). Stephenson 1946, Jour.

Paleontology, v. 20, no. 4, p. 346-347. 

Triebelina crumena (Stephenson). Bold, 1965, Micropaleontology, v. 11, no. 4, p. 389, pi. 2, figs. 9a-c.

Types and dimensions. 

Hypctype

USNM 184327. 

Hypotype 

USNM 184328.

Depth (m) L H W

Adult carapace ______R-321.87 572 311 276

Adult carapace ______R-326.65 622 345 295

Distribution. Post-Miocene: Sand Island hole 

(1). Lower Miocene: reef hole (20). 

Species No. <S (55), R (57).

Adult LV ________R-283.46 

Adult RV __________R-295.50

538 310 135

542 200 119

537 279 215

Triebelina reticulopuncta Benscn

Plate 8, figures 10-12

Triebelina reticulopuncta Benson, 1959, Kansas Univ. Paleont. 

Contr., Arthropoda, Art. 1, p. 44, pi. 2, fig. 1; pi. 8, 

fig. 4.

Haddocks, 1969, U.S. Natl. Mus. Bull. 295, p. 63, pi. 2, 

figs. 5, 6; text-figs. 33e-f.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184329. 

Hypotype

USNM 184330. 

Hypotype

USNM 184331. Adult carapace _____R-295.50 

Hypotype

USNM 184332. Adult LV _____-___S-151.79 638 336 179 

Hypotype

UCB 40515. Adult RV __________S-140.21 547 279 126

Distribution. Upper Miocene: Sand Island hole 

(4). Lower Miocene: reef hole (29).

Species No. S (42), R (44).

Discussion. The Midway specimens do not have 

pits quite as large as those on specimens from Baja 

California described by Benson (1959). Also, the 

ventrolateral ridge is poorly developed or not present at all. Except for these differences, the Midway 

specimens are morphologically similar to those from 

North America.

The species occurs repeatedly in the reef cores 

between R-321.87 m and R-283.46 m, inclusively, 

and then stratigraphically higher in the Sand Island 

cores between S-151.79 m and S-140.21 m. The gap 

between these occurrences probably reflects nonpreservation rather than temporary local extinction.

Triebelina bradyi Triebel

Bairdia trtincata (not Kirkby) Brady, 1890, Royal Soc. Edinburgh Trans., v. 35, p. 494-495, pi. 2, figs. 1, 2. 

Triebelina bradyi Triebel, 1948, Senckenbergiana, v. 29, p.

18-20. 

Key, 1953, Kon. Nederlandse Akad. Wetensch., ser. B, v.

56, p. 158, pi. 1, fig. 5. 

Haddocks, 1969, U.S. Natl. Mus. Bull. 295, p. 63, pi. 2,

fig. 3; text-figs. 32a, 33a-d.

Non Puri, 1960, Gulf Coast Assoc. Geol. Soc. Trans., v. 

10, p. 132, pi. 6, figs. 7, 8.

Type and dimensions. Hypotype USNM 184333. 

Adults LV. S-10.82 m. L=567, #=305, W=ll6. 

Distribution. Pleistocene(?); Sand Island hole

(1).

Species No. S (5).

Discussion. Originally described by Brady 

(1890) from Samoa and New Caledonia and subsequently reported from the Holocene and Pleistocene 

of Indonesia (Key, 1953) and Madagascar (Maddocks, 1969). Triebelina bradyi of Puri (1960) is 

a different species. (See Allison and Holden, 1971.)

Triebelina hanaumaensis (Holden)

Bairdia hanaumaensis Holden, 1967, Pacific Sci., v. 21, no. 1, 

p. 11,12, figs. 5a-h.
F16 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Type and dimensions. Hypotype USNM 184334. 

Penultimate right valve. L=534, #=269, W=125.

Distribution. Pleistocene (?) : reef hole (1). 

Lower Miocene (1).

Species No. R(6).

Discussion. Allowing for growth in accordance 

with Prisbram's law, the individual from R-31.54 m 

would have a length of about 760 p. at the next 

growth stage or would be the same size as the species in the Hawaiian Islands (Holden, 1967). The 

specimen is a young one, as it has no duplicature.

Triebelina sp. 1

Plate 8, figures 14-16

Types and dimensions. 

Depth (m)

Adult carapace __.__R-172.21 

Adult RV _________R-161.39 

Adult carapace ..___R-162.46

L H W

633 282 300

575 255 145

625 270 294

Specimen

USNM 184335. 

Specimen

USNM 184336. 

Specimen

UCB 40516.

Distribution. Lower Miocene: reef hole (1). 

Upper Miocene: reef hole (2).

Species No. R(31).

Discussion. The distribution is clustered on the 

upper Miocene-lower Miocene boundary from R172.21 m to R-161.39 m.

The species appears closely related to the smooth 

Triebelina hanaumaensis (Holden, 1967) from the 

Hawaiian Islands and from higher in the section of 

the reef hole, but it is smaller, more acuminate 

posteriorly, flatter ventrally, and the posterior selvage more prominently developed to almost toothlike.

Triebelina sp. 2

Plate 8, figures 17-19

Type and dimensions. Specimen USNM 184337. 

Adult carapace. R-161.24 m. L=512, #=266, W= 

174

Distribution. Upper Miocene: reef hole (1).

Species No. R(32).

Discussion. Unfortunately, more specimens of 

this interesting species could not be found. It is 

closely related to T. rugosa from Clipperton Island 

and the Caribbean (Allison and Holden, 1971) differing in that it lacks strong marginal denticles and 

has continuous ridge structures on the posterolateral 

and anterolateral surfaces.

Genus PARANESIDEA Maddocks, 1969 

Paranesidea victrix (Brady)

Plate 9, figures 7-9

Bairdia victrix Brady, 1869, Fonds de la mer, v. 1, p. 152, pi.

18, figs. 17, 18.

Brady, 1880, Kept. * * * Voyage * * * Challenger, Zoology, 

v. 1, p. 56, pi. 10, figs. 5a-d.

Puri, 1960, Gulf Coast Assoc. Geol. Soc., Trans., v. 10,

p. 131, pi. 6, fig. 13. 

Bold, 1966a, Caribbean Jour. Sci., v. 6, p. 45, pi. 1, fig. 6.

Types and dimensions. 

Hypotype

USNM 184338. 

Hypotype

USNM 184339. 

Hypotype

USNM 184340. 

Hypotypie

USNM 184341. 

Hypotype

UCB 40517. 

Hypotype

UCB 40518.

Depth (m) L H W

Adult carapace ______R-338.94 1082 690 557

Adult RV ________-.R-338.94 1010 584 300

Adult carapace ______R-338.94 1068 673 511

Adult LV ______.__R-343.21 1105 703 364

Adult LV _________R-343.21 1005 661 333

Adult carapace ______R-338.48 1065 681 521

Distribution. Lower Miocene: reef hole (18).

Species No. R(94).

Discussion. The Midway specimens are within 

the range of variation encountered when comparing 

one author with another. The distinctive faint 

puncta usually reported as covering the surfaces of 

the valves only occur on the midpart in the Midway 

specimens.

The species is widespread in the Southern Hemisphere, originally being described from off Sydney, 

Australia, Tristan da Cunha, and Kerguelen, 

(Brady, 1880), and also throughout the Caribbean 

region north to the Gulf of Mexico. Benson notes 

that in the eastern Gulf of Mexico the species is 

found in depths of 6 to 47 m but is most commonly 

found deeper than 20 m.

Paranesidea handeli Holden, n. sp.

Plate 8, figures 20-22

Diagnosis. Anteromarginal and posteromarginal 

frills well developed; dorsal margin flat, horizontal; 

centrolateral surfaces flattened and posterolateral 

surfaces concave out (as seen dorsally).

Description. Covered by large shallow pits except in areas corresponding to internal duplicatures; 

frills well developed on both valves along anteromargin and posteromargin; inferred females relatively higher. Lateral view: middorsum straight, 

horizontal; anterodorsum and posterodorsum slightly concave up; midventrum concave down. Dorsal 

view: centrolateral surfaces flattened; anterolateral 

surfaces concave out; ends pointed.

Internal features not observed.

Types and dimensions.

Para type

USNM 

Paratype

USNM 

Holotype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

UCB 

Paratype

UCB

Depth (m) LEW

184342. Adult carapace __-__R-343.21 950 545 405

184343. Adult carapace --- .R-343.21 900 524 393

184344. Adult carapace ____.-.R-343.30 941 519 390

184345. Adult carapace __. R-342.90 1025 549 416

184346. Adult carapace _____R-342.90 966 524 398

184347. Adult carapace ______R-337.72 1127 650 483

40519. Adult carapace ______R-337.72 1084 589 451

40520. Adult LV .________.R-337.72 1050 663 __.
LATE CENOZOIC OSTRACODA FIT

Distribution. Lower Miocene: reef hole (22).

Species No. R(92).

Discussion. Even though internal features were 

not observed, the distinctive external morphology 

and ornamentation of the species warrants its description as new.

Paranesidea algocola Haddocks, which is a living 

species in Madagascar, is closely related, but it differs in that it has a rounded ventral margin, evenly 

inflated sides, larger pits, and is somewhat smaller. 

This species is found living in the littoral zone on 

many varieties of calcareous and noncalcareous 

algae (Maddocks, 1969).

Named for George Frederick Handel.

Paranesidea sp. 1 

Plate 9, figure 5

Types and dimensions. 

Specimen

USNM 184348. 

Specimen

USNM 184349. 

Specimen

UCB 40521.

Depth (m) L H W

Adult LV ______R-337.34 894 618 281

Adult carapace ______R-341.38 814 524 442

AduJt carapace ._____R-341.38 818 541 433

Distribution. Lower Miocene: reef hole (4).

Species No. R(93).

Discussion. This species is similar to Paranesidea victrix, but is smaller and has better developed 

marginal denticles and a briefer middorsum. In addition, the surfaces of P. sp. 1 are entirely covered 

with small shallow pits. The species may be a phenotypic variant of Paranesidea victrix.

Paranesidea sp. 2

Plate 9, figures 1-4, 6

Types and dimensions. 

Specimen

USNM 

Specimen

USNM 

Specimen

USNM 

Specimen

USNM 

Specimen

USNM 

Specimen

UCB 

Specimen

UCB

184350.

184351.

184352.

184353.

184354.

40522.

40523.

Adult carapace

Depth (m)

.R-285.90

Adult carapace --_. .R-287.12

Adult

carapace (low form). R-311.35

Adult LV (low form) __R-311.35 

Adult

carapace (high form). R-313.64

Adult LV 

Adult RV

-R-284.68 

.R-284.68

L H W

905 557 433

896 594 448

798 442 325

766 441 192

820 484 350

890 566 284

898 512 241

Distribution. Lower Miocene: reef hole (32).

Species No. R (45).

Discussion. The specimens are confined to two 

nearly adjacent intervals in the reef hole; from R284.68 to R-288.65 m and from R-295.50 to R317.37 m. Specimens from the higher section are 

larger and have a more evenly rounded dorsum (pi. 

9, fig. 6) than those in the lower section (pi. 9, fig. 

4). The smaller forms also differ by showing distinct high and low dimorphism. The species is not 

described because the specimens are poorly preserved.

Genus BAIRDOPPILATA Coryell, Sample, and Jennings, 1935

Bairdoppilata sp. aff. B. bradyi (Bold) 

Plate 1, figures 1, 2; plate 9, figures 20, 21

Types and dimensions. 

Specimen

USNM 184355. 

Specimen

USNM 184356. 

Specimen

USNM 184357. 

Specimen

UCB 40524. 

Specimen

UCB 40525.

Depth (m)

Adult LV ____.__ S-44.20 

Adult LV __.._____KR-12.19

Adult carapace __ R-31.55 

Adidt

carapace (high form). R-120.70 

Adult

carapace (low form). R-120.70

L H W

994 596 277

1025 635 329

1065 650 500

1066 647 530

982 568 434

Distribution. Holocene: Kure atoll lagoon (1). 

Pleistocene: Sand Island hole (38), reef hole (17). 

Post-Miocene: reef hole (4).

Species No. S(8),R(2).

Discussion. Bold (1966a) gave a good synonomy 

of Bairdia bradyi. In my opinion, several species are 

included in this foveolata-bradyi complex, but the 

Midway specimens are more like those described by 

Brady (1880) from the Pacific than those from the 

Caribbean described by Bold (1966a), Puri (1960), 

and Benson and oleman (1963).

Bairdoppilata planolata Holden, n. sp. sensu stricto 

Plate 9, figures 10-12

Diagnosis. Caudal process narrow, extended, 

somewhat upturned; midsurfaces of carapace faintly pitted; greatest height in anterior half. Seen 

dorsally, lateral areas distinctly flattened and anterolateral and posterolateral surfaces straight to 

slightly concave.

Description. Surfaces smooth except for small 

densely packed pits in midlateral areas. Lateral 

view: anterior margin flattened; ventral margin 

straight, sometimes having narrow flange in posterior part; anterodorsal and posterodorsal margins 

concave up; middorsal margin flattened but sloping 

posteriorly; caudal process pointed and extended; 

left valve overlap moderate. Dorsal view: sides distinctly flattened, parallel; anterior and posterior 

lateral areas concave to straight; ends pointed.

Duplicature of moderate width; deep vestibules 

present.

Types and dimensions. 

Paratype

USNM 184358. 

Holotype

USNM 184359. 

Paratype

UCB 40526. 

Paratype

UCB 40527.

Depth (m) L H W

Adult carapace _____R-284.00 954 538 393

Adult carapace ____--R-343.05 861 485 351

Adult RV _________R-283.46 883 449 174

Adult LV _________R-283.46 868 502 233

Distribution. Lower Miocene: reef hole (9).

Species No. R(46).

Discussion. The three subspecies included under 

Bairdoppilata planolata can best be explained as 

phenotypic variants representing slight changes in
F18 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

the environment. None of the three occur with each 

other in any one given sample, yet all have the same 

general stratigraphic range. Bairdoppilata planolata 

ventrocaudata only occurs between R-295.81 m and 

R-313.64 m, which represents the gap in the distribution of B. p. planolata.

The species bears a striking resemblance to 

Bairdia antillea (Miocene of Puerto Rico, see Bold, 

1965) in side view, but not in dorsal view. B. antillea 

does not have flattened sides and is thinner.

Bairdoppilata planolata ventrocaudata Holden, n. (p., n. subsp.

Plate 9, figures 13-16

Diagnosis. Larger and with more ventrally situated caudal process than Bairdoppilata planolata s.s. 

or B. p. magnumcaudata.

Description. Carapace smooth. Caudal process 

very low on ventral margin; pointed and extended. 

Anterior margin high, up to two-thirds carapace 

height. Other features essentially like B. planolata 

s.s.

Types and dimensions. 

Holotype

USNM 184360. 

Paratjrpe

USNM 184361.

Depth (m) L H W

Adult LV _________R-311.35 1190 632 298

Adult RV _________R-311.35 1100 584 256

Distribution. Lower Miocene: reef hole (6). 

Species No. R(60).

Bairdoppilata planolata magnumcaudata Holden, n. »p., n. subsp.

Plate 9, figures 17-19

Diagnosis. Like Bairdoppilata planolata s.s., except wider and having very thick caudal process.

Description. The subspecies closely resembles 

the type; exceptions are pointed out in the diagnosis 

above.

Type and dimensions. Holotype USNM 184362. 

Adult carapace. R-311.81 m. L=982, ff=573, W= 

483.

Distribution. Lower Miocene: reef hole (1).

Species No. R(69).

Discussion. Only one entire specimen was found, 

and no internal features were observed. Bairdoppilata planolata magnumcaudata is named for its relatively large caudal process.

Subfamily BYTHOCYPRIDINAE Maddocks, 1969 

Genus BYTHOCYPRIS Brady, 1880

Bythocypris? compressa Brady

Bythocyprist compressa Brady, 1880, Kept. * * * Voyage * * * 

Challenger, Zoology, 1, p. 46-47, pi. 35, figs. 5a-d.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184370. Adult carapace _____S-146.30 538 283 191 

Hypotype

USNM 184371. Young carapace _____S-146.30 466 234 155 

Hypotype

UCB 40530. Adult carapace _____S-146.30 554 268 190

Distribution. Upper Miocene: Sand Island hole 

(3). Lower Miocene: reef hole (3).

Species M>.-^S(56), R(72).

Discussion. The specimens are comparable with 

Brady's species from 18 fathoms off Tongabatu, 

South Pacific, but smaller. Presumably the Midway 

specimens are adults, tout the level of maturity 

reached is not certain, as internal features were not 

observed.

Bythocypris reniformis Brady

Plate 1, figures 7, 12, 13, 17,18

Bythocypris reniformis Brady, 1880, Kept. * * * Voyage * * *

Challenger, Zoology, v. 1, p. 46, pi. 5, figs. la-1. 

Maddocks, 1969, U.S. Natl. Mus. Bull. 295, p. 88, 90, textfigs 45j-m.

Types and dimensions. 

Hypotype

USNM 184372. 

Hypotype

USNM 184373. 

Hypotype

USNM 184374. 

Hypotype

USNM 184375. 

Hypotype

USNM 184376.

Depth (m) L H W

Adult RV _________S-147.83 1180 550 168

Young RV S-147.83 750 342 142

Adult carapace ______R-321.86 1200 621 397

Adult carapace ______R-317.60 1150 589 356

Adult carapace ______R-172.21 1345 725 485

Distribution. Upper Miocene: Sand Island hole 

(18); reef hole (2). Lower Miocene: reef hole (50).

Species No. «(57), R (33).

Discussion. The immature specimens have the 

proportions of Bythocypris elongata with a length 

twice that of the height. They are always associated 

with the larger B. reniformis types (when abundant) and so are considered the young of that species.

Compared with the forms illustrated by Brady 

(1880) and Maddocks (1969), the Midway specimens have a more obliquely undersloping anterior 

margin and distinct somewhat flattened tripartite 

dorsal margin segments; the anterodorsal and posterodorsal segments are symmetrical. In addition, 

Brady's figure is much more elongate posteriorly.

Genus ANCHISTROCHELES Brady and Norman, 1889

Anchistrocheles sp. 

Plate 11, figures 1, 2

Type and dimensions. Specimen USNM 184627. 

Adult RV. S-79.19 m. L=466, ff=233, T7=97 

Distribution. Pleistocene(?): Sand Island hole

(1). 

Species No. S(26).

Family MACROCYPRIDIDAE Miiller, 1912

Subfamily MACROCYPRIDINAE Miiller, 1912

Genus MACROCYPRIS Brady, 1868

Macrocypris? sp. aff. M.? dimorpha Hazel and Holden

Plate 10, figures 12-14, 19, 20

Macrocyprisl dimorpha Hazel and Holden, 1971, U.S. Geol. 

Survey Prof. Paper 640-D, p. 6, pi. 5, figs. 8, 11, 13, 17, 

19.
LATE CENOZOIC OSTRACODA F19

Types and dimensions. 

Hypotype

USNM 184363. 

Hypotype

USNM 184364. 

Hypotype

USNM 184365. 

Hypotype

USNM 184366. 

Hypotype

USNM 184367. 

Hypotype

UCB 40528.

Depth (m) L H W

Adult carapace _R-320.95 593 346 250

Adult carapace _____R-343.05 680 350 267

Adult carapace ____..S-44.20 652 333 250

Adult carapace ._. ..R-162.76 672 347 265

Adult carapace _____R-320.95 590 351 242

Young carapace ____R-320.50 519 284 203

Distribution. Pleistocene (?): Sand Island hole 

(2). Upper Miocene: reef hole (1). Lower Miocene: 

reef hole (26).

Species No. S (9), R (34).

Discussion. In size, general shape, and dimorphism, the species is closely related to the late Eocene 

(Tertiary b) Macrocyprisl dimorpha. There are 

some consistent morphological differences between 

the two, the Midway specimens being more dorsally 

peaked and having a more concave venter. Internal 

features were not observed in either population, and 

it is best to group the two into one taxon.

The paleoenvironmental preference of the species 

at Tonga was considered to be upper bathyal (Hazel 

and Holden, 1971). The species occurs in various 

samples, especially between R-317.60 to R-343.81 

m, but it is never abundant.

Genus MACROCYPRINA Triebel, 1960

Macrocyprina gracilis (Brady)

Plate 10, figures 6, 7

Pontocypris gracilis Brady, 1890, Royal Soc. Edinburgh Trans.,

v. 35, p. 491, pi. 1, figs. 5, 6. 

Macrocypris gracilis (Brady). Holden, 1967, Pacific Sci., v.

21, p. 16, 17, text-figs. 9a, b.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184368. Adult carapace _____R-317.90 970 390 300 

Hypotype

USNM 184369. Adult carapace _____R-317.90 924 432 299 

Hypotype

UCB 40529. Adult RV ____...__S-87.63 1015 468 233

Distribution. Post-Miocene: Sand Island hole 

(8). Lower Miocene: reef hole (26).

Species No. S (31), R (7).

Discussion. The species is widespread in the 

central Pacific, occurring as a Cenozoic fossil in the 

Hawaiian Islands and Easter Island (Holden, 1967) 

and living in Fiji (Brady, 1890).

Post-Miocene adults in the Sand Island holes are 

larger than the early Miocene adults in the reef 

hole; however, their proportions are the same.

Superfamily CYPRIDACEA Baird, 1845

Family CYPRIDIDAE Baird, 1845

Subfamily CYPRIDOPSINAE Kaufman, 1900

Genus POTAMOCYPRIS Brady, 1870

Potamocypris? sp.

Plate 10, figures 10, 11

Type and dimensions. Specimen USNM 184377.

Adult carapace. S-73.46 m. L=580, #=293, TF=142.

Distribution. Pleistocene (?) : Sand Island hole 

(1).

Species No. S(27).

Discussion. Only one entire specimen was found 

and no internal features were observed. On the basis 

of general morphology, it appears to be a freshwater Cypridid, probably a Potamocypris. The specimen occurs with Cyprideis, a genus of known euryhaline tolerances, and was probably redeposited by 

a stream flowing into the lagoon.

Subfamily PARACYPRIDINAE Sars, 1865

Genus PARACYPRIS Sars, 1865

Paracypris sp. cf. P. rosefieldensis Howe and Law

Plate 10, figures 3, 4

Types and dimensions. 

Depth (m) L H W

688 283 215

694 285 217

Adult RV ...___--__R-320.50 694 285 130

Distribution. Lower Miocene: reef hole (52).

Species No. R(47).

Discussion. The Midway specimens differ from 

the Vicksburg Oligocene Paracypris rosefieldensis 

primarily by having a concave posterodorsum and 

blunter anterior as seen dorsally. A similar species, 

also compared with P. rosefieldensis, is known from 

the Oligocene-Miocene of Puerto Rico (Bold, 1965).

Paracypris franquesi Howe and Chambers

Plate 10, figures 17, 18

Paracypris franquesi Howe and Chambers, 1935, Louisiana 

Geol. Survey Geol. Bull. 5, p. 10, 11, pi. 3, fig. 13; pi. 

4, figs. 15, 19.

Types and dimensions. 

Specimen

USNM 184378. Adult carapace .. R-320.50 

Specimen

USNM 184379. Adult carapace R-317.91 

Specimen

UCB 40531.

Hypotype

USNM 184380. 

Hypotype

USNM 184381.

Adult carapace 

Adult RV -----

Depth (m) 

.R-320.35 

.R-320.95

L H W

772 300 225

767 288 118

Distribution. Lower Miocene: reef hole (3). 

Pleistocene (?) : Sand Island hole (1).

Species No. S (10), R (73).

Discussion. Internally, the Midway specimen (pi. 

10, fig. 17) has fewer radial pore canals than do 

the specimens from the Eocene of Louisiana. The 

species also occurs in the Oligocene of Cuba (Bold, 

1946).

Genus AGLAIOCYPRIS Sylvester-Bradley, 1923

Aglaiocypris sp. 

Plate 10, figures 15, 16

Types and dimensions. 

Specimen

USNM 184382. 

Specimen

UCB 40532.

Adult carapace 

Adult carapace

Depth (m) 

.R-317.90 

.R-317.90

L H W

567 260 187

560 258 190
F20 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Distribution. Lower Miocene: reef hole (6).

Species No. R (74).

Discussion. This species is similar to Aglaiocypris croneisi Teeter, (1966, p. 57), but is larger 

and has a flatter dorsum.

Genus PONTOCYPRELLA Lubimova, 1955

Pontocyprella? sp. 1 

Plate 10, figures 1, 2

Types and dimensions. 

Specimen

USNM 184383. 

Specimen

USNM 184384. 

Specimen

UCB 40533. 

Specimen

UCB 40534.

Depth (m)

Adult carapace ____..R-321.87 

Adult carapace ... __R-287.43 

Adult carapace .. __R-320.96 

Adult carapace _____R-321.41

L H W

566 228 188

594 233 200

600 245 283

582 239 193

Distribution. Lower Miocene reef hole (6). 

Species No. R (54).

Pontocyprella? sp. 2

Plate 10, figures 8, 9 

Types and dimensions. 

Specimen

USNM 184385. 

Specimen

USNM 184386. 

Specimen

USNM 184387. 

Specimen

UCB 40535.

Depth (m) L H W

Adult carapace _____R-320.96 496 212 181

Adult carapace _R-320.96 491 203 174

Adult carapace -___--R-317.60 474 202 165

Adult carapace _____R-317.60 471 203 175

Distribution. Lower Miocene: reef hole (8). 

Species No. R (75).

Superfamily CYTHERACEA Baird, 1850

Family HEMICYTHERIDAE Puri, 1953

Subfamily HEMICYTHERINAE Puri, 1953

Genus HEM1CYTHERE Sars, 1925

"Hemicythere" gordoni Bold

Plate 2, figures 3, 4

Hemicythere gordoni Bold, 1965, Micropaleontology, v. 11, no. 

4, p. 392-393, pi. 5, figs. 7a, b.

Types and dimensions. 

Hypotype

USNM 184424. Adult carapace 

Hypotype

USNM 184425. Adult LV _. 

Hypotype

UCB 40539. Adult LV __

Depth (m) L H W

----R-308.46 669 344 267

 .R-308.46 598 371 151

__R-308.46 600 340 150

Distribution. Lower Miocene: reef hole (5). 

Upper Miocene: Sand Island hole (1).

Species No. S (62), R (64).

Discussion. The Midway specimens are morphologically identical to Hemicythere gordoni figured 

by Bold (1965) from the Oligocene-Miocene of 

Puerto Rico except that in those from Midway the 

greatest width is just posterior to midlength instead 

of at midlength.

Genus CAUDITES Coryell and Fields, 1937 

Caudites spp.

Plate 1, figure 10; plate 10, figure 5

Types and dimensions. 

Specimen

USNM 184388. 

Specimen 

USNM 184389.

Depth (m) L H W

Young RV _______R-31.55 450 250 80

Adult RV ________S-140.21 641 291 102

Distribution. Post-Miocene: Sand Island hole 

(2).

Species M>.-^S(43), R(8).

Discussion. In many ways one of these individuals (pi. 1, fig. 10) resembles a species of Caudites 

from the Galapagos Islands.

This genus is not common in the insular Pacific 

but is fairly widespread in the East Indies, Indian 

Ocean (McKenzie, 1967a), and the Caribbean.

Genus OR10N1NA Pnri, 1954 

Orionina flabellacosta Holden, n. sp.

Plate 3, figures 5-7; plate 11, figure 6

Diagnosis. Lateral ridges weakly developed; 

about five thin ridges flair out from subcentral 

swelling toward anterior margin; dimorphism pronounced. Duplicature atypically lacking pillar structures ; radial pore canals abundant, unbranched.

Description. Lateral view: subquadrate; posterior margin subtruncate; ventral margin straight 

to slightly concave; dorsal outline undulating because of posterodorsal swelling. Ornamentation of 

poorly developed lateral ridges and shallow reticula, 

each of which contains small pits; ventrolateral and 

posterodorsal ridges best developed; about five thin 

ridges fanning out from subcentral swelling to anterior margin. Dimorphism pronounced with long 

( 3 ) and short ( $ ) forms. Dorsal view: greatest 

width in posterior third at posterodorsal swelling; 

subcentral swelling subdued; anterior blunt because of moderately developed rim.

Hinge holamphidont: left valve median bar 

smooth. Adductor-scar pattern basic vertical row 

of four; middle two scars divided; three frontal 

scars. Normal pores small, moderately abundant. 

Duplicature narrow; many straight unbranched 

radial pore canals with median enlargements. 

Vestibules absent.

Types and dimensions. 

Holotype

USNM 184390. 

Para type

USNM 184391. 

Paratype

USNM 184392. 

Paratype

USNM 184393.

Depth (m) L H W

Adulttf carapace ____R-344.12 824 418 350

Adult? LV ________R-343.30 774 468 165

Adult? LV ________R-335.09 656 388 162

Adult? RV ________R-344.12 655 366 83

Distribution. Lower Miocene: reef hole (75).

Species No. R(89).

Discussion. Orionina is characteristically a Caribbean genus but does occur along the west coast of 

North America and in the Galapagos Islands (McKenzie, 1967a). This species is very distinct from 

others in the genus.
LATE CENOZOIC OSTRACODA F21

Genus POKORNYELLA Oertli, 1956 

Pokornyella deformis (Reuss)?

Plate 1, figure 4; plate 11, figures 7-9

Aurila deformis (Reuss). Bold, 1963a, Micropaleontology, v. 

9, no. 4, p. 386, pi. 7, fig. 4.

Procythereist deformis (Reuss) ? Bold, 1965, Micropaleontology, v. 11, no. 4, p. 396, pi. 5, figs. 4a-b.

Types and dimensions. 

Hypotype

USNM 184394. 

Hypotype

USNM 184395. 

Hypotype

USNM 184396. 

Hypotype

USNM 184397. 

Hypotype

UCB 40536. 

Hypotype

UCB 40537.

Depth (m) L H W

Adultd1 carapace R-300.59 767 486 375

Adult? carapace _.R-300.59 641 435 367

Adujt? RV -R-300.59 658 402 183

Adult? carapace ____R-317.60 601 383 350

Adultd1 carapace ____R-300.23 689 586 363

Adult? carapace ____R-300.23 513 433 346

Distribution. Lower Miocene: reef hole (55).

Species No. R(41).

Discussion. In the Caribbean the species is 

known from the lower to upper Miocene of Trinidad (Bold, 1963a) and lower Miocene of Puerto 

Rico (Bold, 1965). Though the Midway specimens 

vary considerably, some of them are morphologically 

identical with specimens of P. deformis from Puerto 

Rico. These specimens are identical with Bold's 

Caribbean species, but their relationship to Cypridina deformis Reuss (Reuss, 1850) is uncertain.

Pokornyella pseudojaponica Holden, n. sp. sensu stricto 

Plate 2, figures 9-18; plate 11, figures 19-21

Diagnosis. Highly arched, lenticular, deeply reticulate Pokornyella with dorsally overreaching left 

valve, curved ventral ridge, and brief posterodorsal 

ridge. Reticula bordering anterior margin especially large.

Description. Lateral view: left valve broadly 

and highly arched, overreaching dorsally flattened 

right valve; caudal process usually small, short, 

near venter margin, concave above; venter sinuous 

to slightly rounded. Ornamentation of large deep 

pits (or small deep reticulations), those paralleling 

the anterior margin being much larger. Low ventral 

ridge sometimes posteriorly enlarged as alar structure; brief posterodorsal ridge usually present. 

Dorsal view: lenticular, ends pointed; greatest width 

at or just posterior to midlength, alae sometimes 

projecting.

Nonvestibulate; radial pore canals fairly abundant, about 24 anteriorly, without enlargements, simple, straight. Hinge amphidont, median bar smooth, 

teeth not heavy; normal pores abundant, coinciding 

with large internal pits. Four adductor scars, two 

frontal scars; large muscle-attachment boss dorsal 

to subcentral area.

Types and dimensions. 

Depth (m)

184398. Adult carapace S-147.37

184399. Adult carapace R-172.21

184400. Adult carapace R-172.21

184401. Adult RV __________R-171.91

184402. Adult RV ____ S-147.37

184403. Adult RV _________S-147.37

184404. Adult LV ____-____.S-140.21

184405. Adult LV -----S-149.66

184406. Adult carapace R-160.63

184407. Adult RV _________S-140.21

184408. Adult carapace ______R-161.24

Holotype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM 

Paratype

USNM

L

778

749

774

680

734

708

716

830

783

683

636

H

473

498

462

391

419

425

483

549

473

388

400

W

221

440

468

468

240

250

234

233

424

200

383

Distribution. Post-Miocene: Sand Island hole 

(50). Upper Miocene: Sand Island hole (120). 

Lower Miocene: reef hole (60).

Species No. S (33), R(24).

Discussion. Closely related to Pokornyella calix 

(lower Chattian, Switzerland) described by Oertli 

(1956) and P. japonica (Holocene, Japan) of Ishizaki (1968) in shape and ornamentation. All three 

species have the enlarged anteromarginal reticulations. Pokornyella pseudojaponica differs primarily 

from the Oligocene species by having a ventral and 

posterodorsal ridge and from P. japonica by lacking the horizontal lateral ridges. Aurila sp. aff. A. 

cicatricosa of Bold (1966b) (Pliocene, Venezuela) 

is also a isimilar species but appears to lack the 

Pokornyella-type caudal process.

Pokornyelia pseudojaponica inflata Holden, n. sp., n. subsp.

Plate 11, figures 10, 11

Diagnosis. Like P. pseudojaponica s.s., but greatly inflated and lacking the ventral and posterodorsal 

ridges and almost all the caudal process.

Types and dimensions. 

Holotype

USNM 184409. 

Paratype

USNM 184410. 

Paratype

UCB 40538.

Depth (m) L H W

Adult carapace -___.S-138.23 784 528 496

Adult carapace _____S-138.23 750 510 483

Adult carapace ____S-140.21 702 466 458

Distribution. Upper Miocene: Sand Island hole 

(16).

Species No. S(34).

Discussion. Toward the end of its range at Midway Island, Pokornyella pseudojaponica rapidly 

becomes highly inflated. This change begins at S140.21 m and continues at S-138.23 m. At S-135.94 

and S-135.65 only the inflated subspecies is found.

Genus RADIMELLA Pokorny, 1968 

Radimella convoluta (Brady)

Plate 2, figure 1; plate 11, figures 14, 15

Cythere convoluta Brady, 1868, Ann. and Mag. Nat. History, 

ser. 4, v. 2, no. 9, p. 182, pi. 12, figs. 3, 4.
F22 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Brady, 1880, Rept. * * * Voyage * * * Challenger, Zoology,

v. 1, p. 92, pi. 22, figs. 3a-d.

Mutilusl aff. M.I oahuensis Holden. Resig, 1969, Univ. Hawaii 

Inst. Geophys., HIG-69-2, pi. 9, fig. 7.

Diagnosis. Dorsolateral ridge continuous with 

ventrolateral ridge around posterior forming right 

angle in posterodorsum; four other parallel lateral 

ridges trend toward anterior in ventral half.

Description. Lateral view: carapace subquadrate; greatest height at anterocardinal angle; 

ventral margin straight; dorsal margin straight to 

slightly arched; posterior margin subtruncate with 

low brief caudal process. Ornamentation of unbroken anteriorly sloping dorsolateral ridge bending through 90° at the posterodorsum to form a vertical posterior ridge which continues with a long 

curved ventral ridge; four subparallel centrolateral 

ridges sloping to ventral half of anterior. Light 

reticula between ridges. Dorsal view: anterior and 

posterior blunt; carapace evenly inflated; greatest 

width central.

Hinge apparently holamphidont; median bar of 

left valve smooth. Nonvestibulate duplicature 

traversed by many radial pore canals (75-100 ± in 

anterior), most with midswellings. Four adductor 

muscle scars in vertical row with the middle two 

divided; three small frontal scars.

Types and dimensions. 

Holotype

USNM 184411. 

Para type

USNM 184412. 

Paratype

USNM 184413.

Depth (m) L H W

Adult carapace __S-73.46 710 438 338

Adult carapace _-___S-73.46 670 420 322

Adult broken LV ____S-73.46 _ 425 175

Distribution. Pleistocene (?) : Sand Island hole 

(13); reef hole (4).

Discussion. The species was also found by J. E. 

Hazel (in Resig, 1969) in the Pleistocene from the 

subsurface at Hawaii at 660.3 feet ( 198 m).

Radimella convoluta occurs intermittently in the 

Pleistocene (?) of the Sand Island borehole from S45.11 m to S-78.63 m and in the reef borehole only 

at R-89.46 m. It is probably derived from Radimella 

polycosta, which is last found in the upper Miocene 

in both boreholes at S-138.23 m and R-158.34 m. 

Radimella convoluta differs from R. polycosta by 

lacking two of the concentric anterolateral ridges 

and by having an entire dorsolateral ridge; otherwise the two species appear similar.

Radimella polycosta Holden, n. sp., sensu stricto 

Plate 1, figures 8, 9; plate 2, figure 2; plate 11, figure 13

Diagnosis. Lateral surface ornamented by eight 

horizontal ridges: top ridge short, second ridge down 

sinuous, third ridge down short and located in anterior half of valve, ridges seven and eight down in 

the ventrolateral area continue into anterolateral 

area and parallel the anterior margin. 

Types and dimensions. 

Paratype

USNM 184414. 

Paratype

USNM 184415. 

Holotype

USNM 184416. 

Paratype

USNM 184417.

Depth (m) L H W

Adult carapace ______R-308.46 617 392 303

Adult carapace __ .R-308.76 672 403 343

Adult LV _________S-140.21 618 367 160

Adult LV _________S-140.21 594 361 148

Distribution. Upper Miocene: Sand Island hole 

(3) ; reef hole (26). Lower Miocene: reef hole (11).

Species No. S (39), R (26).

Description. Lateral view: subquadrate; 

straight dorsum almost parallel to straight venter; 

caudal process stubby; anterior slightly obliquely 

rounded; 7-11 horizontal lateral ridges of which the 

dorsal three always short; two anterior concentric 

lateral ridges; two anterior marginal ridges; small 

reticula between ridges; eye tubercles prominent. 

Dorsal view: lenticular; ends bluntly pointed; sides 

flattened; posterior depression between elevated 

dorsal ridges.

Hinge holamphidont; median left valve bar 

smooth. Duplicature of moderate width, nonvestibulate; many radial pore canals with small midswellings, tendency to be paired; normal pores very 

small. Four entire adductor scars in vertical row; 

two circular frontal scars.

Discussion. See Radimella resigi.

Radimella polycosta rugosa Holden, n. sp., n. subsp.

Plate 2, figures 6, 7; plate 11, figure 16

Diagnosis. Like Radimella polycosta s.s. but having much heavier lateral ridges and more inflated 

carapace.

Types and dimensions. 

Holotype

USNM 184418. 

Paratype

USNM 184419. 

Paratype

USNM 184420.

Depth (m) L H W

Adult? LV_. _____R-173.28 621 375 207

Adult? RV ________R-173.28 590 344 167

Adultcf RV _-_---R-173.28 639 360 160

Distribution. Lower Miocene: reef hole (23). 

Species No. R(36).

Genus AURILA Pokorny, 1955 

Aurila sp. aff. A. lincolnensis (LeRoy)

Plate 2, figure 8; plate 11, figure 12; plate 16, figure 22

Types and dimensions. 

Specimen

USNM 184421. 

Specimen

USNM 184422. 

Specimen

USNM 184423.

Depth (m)

Adult LV _________R-321.87 

Adult carapace -- ...R-320.65 

Adult carapace -- -..S-152.25

L It W

499 311 135

495 321 235

557 350 232

Distribution. Upper Miocene: Sand Island hole 

(9). Lower Miocene: reef hole (20).
LATE CENOZOIC OSTRACODA F23

Species No. S (63), R (65).

Discussion. The species is very similar to Aurila 

laevicula (Edwards, 1944) from the Miocene of the 

United States East coast and Caribbean (Bold, 

1963a) and to A. lincolnensis from Pliocene to Holocene of California and Baja California (Benson, 

1959). Subtle differences in shape and ornamentation separate these two from the Midway species.

The one specimen from which good musculature 

was preserved shows three frontal scars and two of 

the adductors divided. This pattern is typical for 

Aurila.

Aurila sp. 

Plate 11, figures 17, 18

Type and dimensions. Specimen USNM 184426. 

Adult RV. R-73.46 m. L=534, ff=317, IF=109.

Distribution. Pleistocene (?): Sand Island hole 

U).

Species No. S(24).

Genus PROCYTHEREIS Skogsberg, 1928

"Procythereis" northpacifica Holden, n. sp.

Plate 2, figures 19-21

Diagnosis. Strongly alate; sides flattened; ornamentation lacking to deeply but sparsely pitted; 

few random tubercles.

Description. Lateral view: subquadrate; venter 

straight; dorsum straight to slightly rounded; 

posterior truncate; anterior slightly rounded; surfaces with shallow to deep sparse large round pits, 

some specimens apparently smooth; alae along 

ventral midhalf of valve smooth; eye tubercles distinct. Dorsal view: arrowhead shaped; greatest 

width in posterior three-quarters; posterior and anterior lateral areas compressed; dorsum and anterior heavily rimmed.

Hinge holamphidont; posterior tooth of right 

valve reniform; median bar of left valve smooth. 

Normal pores abundant, deep; duplicature moderate 

width. Four undivided adductor scars; two frontal 

scars.

Types and dimensions. 

Paratype

USNM 184429. 

Para type

USNM 184430. 

Holotype

USNM 184431.

Depth (m) L H W

Adult LV _________S-147.37 718 423 233

Adult RV __________S-147.37 714 409 228

Adult carapace _____S-152.40 662 415 432

Distribution. Upper Miocene: reef hole (26) ; 

Sand Island hole (32).

Species No. S (44), R (21).

Discussion. The species has a strong resemblance to members of the genus Nephokirkos (Howe, 

1951) except that it lacks a distinct caudal process.

Together with Nephokirkos ? sp. of Hazel and Holden 

(1971) from the Eocene of Tonga, it probably represents a distinct genus. Another closely related 

species from Bass Strait, Australia, has been seen 

by the writer.

Subfamily COQUIMBINAE Ohmert, 1968 

Geuus MUELLERINA Bassiouni, 1965

Muellerina? sp. 

Plate 5, figures 17, 18

Types and dimensions. 

Specimen

USNM 184427. 

Specimen

USNM 184428.

Depth (m)

Adult carapace _____R-311.35 

Adult carapace ____R-311.81

L H W

613 326 242

600 319 251

Distribution. Lower Miocene: reef hole (4). 

Species No. R(66).

Subfamily THAEROCYTHERINAE Hazel, 1967 

Genus QUADRACYTHERE Hornibrook, 1953

Quadracythere trijugis Holden, n. sp. 

Plate 3, figures 14, 15; plate 5, figure 24; plate 12, figure 9

Diagnosis. -Slightly concave venter and parallel 

dorsum; caudal process concave above and below, at 

midheight; several discontinuous lateral ridges and 

small to large reticula.

Description. Lateral view: subquadrate; venter 

slightly concave, parallel to slightly arched dorsum, 

anterior bluntly rounded; pointed caudal process, at 

midheight, concave above and below; several semihorizontal discontinuous lateral ridges; long curved 

alar ridge divided; posterodorsal ridge complex, prominent; various-sized reticula between ridges. Dorsal view: anterior blunt; anterior and posterior 

lateral surfaces compressed; equally wide along midhalf with median sulcus at midlength.

Hinge holamphidont; median bar of left valve 

lightly crenulate; posterior tooth of right valve reniform. Duplicature nonvestibulate, of moderate 

width; many simple straight radial pore canals 

with small midswellings. Four adductor scars; two 

small circular frontal scars.

Types and dimensions. 

Holotype

USNM 184432. 

Para type

USNM 184433. 

Para type

USNM 184434. 

Paratype

USNM 184435.

Depth (m) L H W

Adult carapace _____S-140.21 783 466 583

Adult carapace _____R-326.14 710 433 386

Adult LV ___.-_____S-140.21 734 436 192

Young RV _________S-140.21 586 323 148

Distribution. Upper Miocene: Sand Island hole 

(3). Lower Miocene: reef hole (1).

Species No. S(45), R(59).

Discussion. The late Miocene specimens have 

two well-developed ridges on the subcentral swelling reminiscent of many species of Jugosocythereis. 

These are barely discernible on the single early Mio-
F24 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

cene specimen from the reef hole, which is also more 

evenly reticulate like Q. aequibilis from which this 

species probably originated. The immature individuals from the upper Miocene (pi. 5, fig. 24) closely 

resemble adults of Q. spica from the lower Miocene 

(pi. 5, figs. 22, 25).

Name. tri = three, jugis = linked fii a team, referring to the three closely related, jfnd probably 

consecutively derived, species of Quaaracythere at 

Midway.

Quadracythere aequabilis Holden, n. sp. 

Plate 17, figures 11-14

Diagnosis. Like Q. trijugis, but devoid of lateral 

ridges; reticula heavily and evenly distributed, fanning out from subcentral swelling in anterolateral 

area; alar ridge poorly developed or absent; posterodorsal tubercle brief to large and bulbous.

Description. Lateral view: venter concave at inturned area, broadly convex in posterior part with 

well-developed flangelike ridge; dorsum straight to 

gently rounded, subparallel with venter; brief caudal 

process at midheight; surface evenly and deeply 

reticulate, fanning out from subcentral swelling toward anterior margin; ventral alae absent to poorly developed, small posteroventral tubercle always 

present; small posterodorsal tubercle sometimes 

greatly enlarged into bulbous structure. Dorsal 

view: sublenticular; ends blunt; anterolateral and 

posterior surfaces compressed; greatest width in 

posterior third.

Hinge holamphidont, median bar faintly crenulate. Duplicature rather narrow, nonvestibulate; 

radial pore canals abundant, about 35 in anterior, 

each with small midswelling. Abundant normal 

pores forming distinct internal pits. Four adductor 

scars; two small round frontal scars.

Types and dimensions. 

Panatype

USNM 184436. 

Paratype

USNM 184437. 

Paratype

USNM 184438. 

Holotype

USNM 184439. 

Paratype

UCB 40540.

Depth (m) L H W

Adultd1 carapace ____R-320.35 739 448 385

Adultd1 LV ________R-320.35 738 456 194

Adult? carapace _____R-320.35 , 699 434 400

Adult? cairapace _____R-336.58 708 433 370

Adultd1 carapace ____R-338.12 820 476 376

Distribution. Lower Miocene: reef hole (49).

Species No. R(85).

Discussion. In the younger part of its range most 

of the specimens have greatly inflated posterodorsal 

and posteroventral tubercles. These features may 

represent responses to local environmental changes, 

as other specimens of the same species in the same 

sample are quite lenticular.

The pattern of ornamentation of Q. aequabilis, 

especially with the fanning out of reticula on the 

anterior surface, indicates close affinities and probably direct ancestry to Q. trijugis higher in the section and descent from Q. spica lower in the section.

Name. aequabilis = uniform, equitable, referring to the even reticulate pattern, which is the 

dominant ornamentation.

Quadracythere spica Holden, n. sp.

Plate 5, figures 22, 25

Diagnosis. Loxoconcha-form; evenly reticulate, 

without lateral ridges; posterodorsal and posteroventral spikelike tubercles.

Description. Lateral view: dorsum straight; 

venter sinuous; well-developed caudal process in 

lower half, concave above; ventral alae absent; 

posterodorsal and posteroventral tubercles spikelike, 

large; surface evenly reticulate, fanning out in all 

directions from subcentral tubercle; eye tubercle 

prominent. Dorsal view: terminally blunt; anterolateral and posterolateral areas compressed; greatest width at posteroventral tubercle.

Types and dimensions. 

Paratype

USNM 184440. 

Holotype

USNM 184441. 

Paratype

UCB 40541.

Depth (m) L H W

Adult LV _________R-343.05 673 384 182

Adult carapace ____R-343.30 618 358 316

Adult carapace ______R-343.30 612 338 290

Distribution. Lower Miocene: reef hole (3). 

Species No. R(99).

Genus JUGOSOCYTHERE1S Puri, 1957

Jugosocythereis canaliculata Holden, n. sp. sensu stricto

Plate 4, figure 22, 23; plate 12, figure 8; plate 14, figure 16

Diagnosis. Covered with narrow furrows or 

coalesced reticula; elongate alae prominent; subcentral and posterodorsal tubercles poorly developed.

Description. Lateral view: dorsum and venter 

slightly rounded; ventral caudal process straight to 

somewhat concave above; anterior faintly flattened 

in dorsal part; surface covered with narrow 

grooves alined vertically in posterior, sloping posteriorly on alae, sloping anteriorly elsewhere; large 

alae slightly curved; eye tubercles prominent. Dorsal view: arrow shaped; anterior blunt; posterior 

compressed, pointed.

Hinge amphidont; left valve median bar smooth; 

right valve terminal tooth reniform. Nonvestibulate; radial pore canals abundant, unbranched, with 

median swellings. Four adductor scars, the middle 

two divided; two circular frontal scars.
LATE CENOZOIC OSTRACODA F25

Types and dimensions. 

Holotype

USNM 184442. 

Para type

USNM 184443. 

Paratype

USNM 184444. 

Paratype

UCB 40542.

Depth (m) L H W

Adult LV __ __S-45.11 586 325 183

Adult carapace _.-._._S-45.11 632 327 365

Adult carapace ___R-22.25 622 353 374

Adult LV _________R-138.32 616 360 200

Distribution. Pleistocene (?): Sand Island hole 

(20) ; reef hole (1). Post-Miocene: reef hole (1).

Species Afo. S(ll), R(3).

Discussion. Internal features and distinctive 

ornamentation indicate a close relationship to the 

late Cenozoic /. venulosus from the Hawaiian Islands 

(Holden, 1967). That species, however, is trituberculate, whereas /. canaliculata has only the alae 

well developed.

Name. canaliculata (L.) = grooved.

Jugosocythereis canaliculata reticulata Holden, n. sp., n. subsp. 

Plate 4, figures 1-5; plate 12, figure 20

Diagnosis. Like /. canaliculata s.s., but grooves 

broken up into elongate reticulae; alae much less 

developed.

Types and dimensions. 

Holotype

USNM 184445. 

Paratype

USNM 184446. 

Paratype

USNM 184447. 

Paratype

USNM 184448. 

Paratype

USNM 184449. 

Paratype

USNM 184450.

Depth (m) L H W

Adult LV S-86.87 631 364 176

Adult RV _S-86.87 634 346 170

Adult carapace ____S-97.84 582 334 288

Adult carapace _----.-_S-90.37 659 399 340

Adult carapace ___.S-90.37 611 336 324

Adult LV -..-_______S-91.14 600 342 181

Distribution. Pleistocene (?) : Sand Island hole 

(850) ; reef hole (27).

Species Afo. S(32), R(18).

Discussion. Extremely abundant in the Sand 

Island hole between S-85 m and S-98 m in fauna 

S4 , often accounting for as much as 90 percent of the 

fauna.

Jugosocythereis lactea (Brady) 

Plate 3, figures 22, 23; plate 12, figures 15-17

Cythere lactea Brady, 1866, Zool. Soc. [London] Trans., v. 5,

p. 377, pi. 60, figs. 3a-c. 

Brady, 1880, Kept. * * * Voyage * * * Challenger, Zoology,

v. 1, p. 91, pi. 22, figs. la-d. 

Chapman, 1914, Royal Soc. Victoria Proc., new ser., v.

27, p. 36, pi. 6, fig. 15.

Types and dimensions.-

Hypotype

USNM 184451. 

Hypotype

USNM 184452. 

Hypotype

USNM 184453. 

Hypotype

USNM 184454.

Depth (m)

Adult RV _____.....S-73.46 

Adult carapace __..S-74.22 

Adult carapace -_.__R-31.55 

Adult LV _________S-73.46

L H W

540 303 173

582 326 314

562 339 188

584 355 170

Distribution. Pleistocene (?): Sand Island hole 

(8); reef hole (2).

Species No. S (1),R(9).

Discussion. This species was originally reported 

by Brady (1866) off Australia at 17 fm and again 

(1880) at lat 40°S. in the mid-Pacific at 420 fm. 

Specimens from the mid-Pacific location are probably in redeposited material. Surprisingly, I have 

found the species abundant at the Line Islands, Fiji, 

New Caledonia, and Australia. A small species, it 

was probably overlooked by Brady in prolific samples or else considered a young of Jugosocythereis 

deltoides, which almost always is associated with it.

Chapman (1914) reported the species at 310-320 

and 562-564 feet in the Funafuti drill holes. The 

age of the Funafuti section is Pleistocene to Holocene (Ladd and others, 1970) and not Miocene, as 

originally believed.

Jugosocythereis pannosa (Brady)

Plate 3, figures 17-21; plate 12, figure 14

Cythere pannosa Brady, 1869, Fonds de la mer, v. 1, p. 154, pi.

19, figs. 1, 2. 

Cythereis vicksburgensis Howe and Law, 1936, Louisiana Geol.

Survey Geol. Bull. 7, p. 34, pi. 4, fig. 4, pi. 5, figs.l, 2. 

Bold, 1946, Amsterdam, p. 89, pi. 10, fig 5. 

Cythereis bicarinata Swain, 1946, Jour. Paleontology, v. 20, no.

4, p. 376, pi. 54, figs. 7a-d; pi. 55, figs. la-e. 

Hermanitesl pannosa (Brady). Bold, 1957, Micropaleontology,

v. 3, no. 3, p. 240, pi. 2, fig. 2. 

Jugosocythereis bicarinata (Swain). Puri, 1957, Florida Geol.

Survey Bull. 38, p. 200, pi. 12, figs. 11-20. 

Jugosocythereis vicksburgensis (Howe and Law). Bold, 1963a,

Micropaleontology, v. 9, no. 4, p. 388, 389, pi. 7, fig. 6. 

Jugosocythereis pannosa (Brady). Bold, 1966a, Caribbean

Jour. Sci., v. 6, no. 1-2, p. 47, pi. 1, fig. 11.

Types and dimensions.-

Hypotype

USNM 184471. 

Hypotype

USNM 184472. 

Hypotype

USNM 184473. 

Hypotype

USNM 184474. 

Hypotype

USNM 184475. 

Hypotype

USNM 184476.

Depth (m)

Adult carapace _____R-355.09 

Adult carapace ____R-355.09 

Adult carapace _____R-355.09 

Adult carapace -.._..R-343.30 

Adult carapace __-._S-149.05 

Adult LV _________S-152.40

L H W

648 383 380

671 386 397

653 400 364

658 410 393

668 410 400

653 394 202

Distribution. Upper Miocene: Sand Island hole 

(4). Lower Miocene: reef hole (19).

Species No. S(58), 11(87).

Discussion. This species is known from the Oligocene to Holocene in the Caribbean-gulf coast 

region of North America. At Midway, the late Miocene specimens have fewer reticulations than the 

early Miocene specimens and the bladelike lateral 

ridges are more subdued.

Genus TENEDOCYTHERE Sissingh, 1972 

Tenedocythere turda Holden, n. sp.

Plate 1, figure 11; plate 12, figures 6, 7

Diagnosis. Large; highly inflated; large equal
F26 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

reticula; faint lateral ridges on subcentral tubercle; 

long thin dorsolateral ridge.

Description. Highly inflated; covered with large 

shallow reticula. Lateral view: subquadrate; 

straight dorsum almost parallel with straight 

venter; anterior finely denticulate, slightly flattened 

in upper part; posterior blunt with five short spines 

in ventral half, concave in upper half. Entirely covered with large equal shallow reticulations. Ventrolateral and posterolateral ridges thin, long; faint 

ridges in subcentral area; small posterolateral ridge. 

Dorsal view: length about 1.75 times width; equally 

wide along midhalf; terminally blunt.

Hinge amphidont, median bar smooth. Nonvestibulate; radial pore canals straight, unpaired, some 

with median swellings, about 20-25 anteriorly. 

Normal pores moderately abundant, forming internal pits; four adductors; two frontal scars.

Types and dimensions. 

Paratype

USNM 184455. 

Holotype

USNM 184456. 

Paratype

USNM 184457. 

Paratype

USNM 184458. 

Paratype

UCB 40543.

Depth (m) L H W

Young RV ______ -R-338.94 749 456 263

Adult carapace ______R-317.37 940 575 542

Adult LV _________R-317.37 880 500 250

Adult carapace _____R-296.66 828 467 463

Adult carapace ______R-296.66 842 483 484

Distribution. Lower Miocene: reef hole (25).

Species No. R(61).

Discussion. This species is related to "Cythere 

prava" of Brady (1880) from the Admiralty Islands 

(=Bradleya sp. a of Apostolescu (1967) from New 

Caledonia). The stratigraphically higher specimens 

at R-296.66 m are more like the Holocene "Cythere 

prava" than those at R-317.37 m. Instead of prominent midlateral ridges, however, they have three 

(one weak), not two, subcentral ridges and an unbroken midlateral ridge. Seen dorsally, the modern 

species appears sulcate because of its broken ridge.

Name. turda (L.) = plump, stout.

Tenedocythere quadranodosa Holden, n. sp. 

Plate 5, figures 19-21; plate 12, figures 10-12

Diagnosis. Straight venter and dorsum converging posteriorly; four large nodes; subcentral, posterodorsal, posteroventral, and posterolateral, equally developed; outer anteromarginal ridge set back 

on lateral surface.

Description. Lateral view: subquadrate wedgeshaped; dorsum and ventrum straight, converging 

posteriorly; anterior finely denticulate, broadly 

rounded, slightly flattened dorsally; posterior truncate; surface reticulate; four equally large tubercles 

at subcentral area, ventral and dorsal posteriors and 

in posterolateral area; subcentral node surmounted 

by three faint ridges; two anterior ridges with large 

reticula between, outermost ridge set back on lateral

surface. Dorsal view: greatest width at subcentral 

tubercle; bluntly pointed at ends.

Hinge holamphidont, median bar smooth. Nonvestibulate; radial pore canals simple, straight, 

without midswellings, about 25 anteriorly; four adductor scars; two frontal scars.

Types and dimensions. 

Paratype

USNM 184459. 

Holotype

USNM 184460. 

Paratype

USNM 184461. 

Paratype

USNM 184462. 

Paratype

UCB 40544.

Depth (m) L H W

Adult LV __.______S-141.73 748 467 226

Adult RV __________S-141.73 774 450 209

Adult LV _________S-140.21 752 473 228

Adult LV __________S-140.21 734 467 217

Adult LV __________S-140.21 770 447 216

Distribution. Upper Miocene: Sand Island hole 

(27).

Species No. S(46).

Discussion. Similar in basic morphology to 

Tenedocythere turda and "Cythere prava" of Brady 

(1880) except not as inflated, and the various lateral 

ridges are locally coalesced into four distinct 

tubercles.

Tenedocythere setigera Holden, n. sp.

Plate 2, figure 5; plate 3, figures 8-13; plate 5, figure 23; 

plate 12, figure 13

Diagnosis. Short low incomplete ridges variably 

developed over lightly reticulate surface; some 

pustules. Anteromarginal rim and subcentral tubercle weakly developed.

Description. Carapace subquadrate, dorsal margin and ventral margins slightly converging posteriorly. Posterior subtruncate; caudal process near 

venter, with three terminal spines and four larger 

spines along posteroventer. Surface shallow to deeply reticulate with about six pustules, sometimes having weak, discontinuous anteroventrally trending 

ridges, especially on subcentral tubercle. Alae well 

developed, thin.

Hinge holamphidont, terminal teeth of right valve 

smooth; median bar of left valve smooth. Radial pore 

canals simple, about 20 anteriorly, 20 posteriorly, 

forming fan-shaped spray in caudal area. Four adductor scars on side of subcentral depression; two 

frontal scars. Prominent boss above frontal scars.

Types and dimensions. 

Paratype

USNM 

Paratype

USNM 

Holotype

USNM 

Paratype

USNM 

Paratype

USNM 

Pajratype

USNM 

Paratype

USNM 

Pairatype

USNM 

Paratype

UCB

Depth (m) L H W

184463. Adult LV _________R-343.30 683 420 200

184464. Adult carapace R-343.30 733 422 386

184465. Adult LV _________-R-338.94 672 408 192

184466. Adult? RV _______ -R-309.46 619 365 206

184467. Adult carapace ______R-311.37 678 415 368

184468. Adult carapace ______R-296.66 670 408 400

184469. Adult carapace ______R-320.65 636 391 366

184470. Adult carapace ____. R-320.65 608 374 349

40545. Adult carapace ______R-338.94 610 387 350
LATE CENOZOIC OSTRACODA F27

Distribution. Lower Miocene: reef hole (136).

Species No. R(62).

Discussion. Tenedocythere setigera is highly 

variable in the reef hole section between 325 and 

345 m; one variant resembles "Procythereis" northpad fica in some respects. (See pi. 3, figs. 12, 13.) 

Two forms within the same sample often show a 

gradation, which indicates that they are all the same 

species.

Genus HERMANITES Puri, 1955 

Hermanites hawaiianensis Holden, n. sp.

Plate 5, figure 13

Hermanites sp. Holden, 1967, Pacific Sci., v. 21, no. 1, p. 42, 

43, text-figs. 32a-c.

Diagnosis. Dorsal margin straight; well-developed ridge from posterodorsal tubercle to ventral 

ridge; ornamentation of well-defined, evenly spaced 

reticulations radiating out in all directions from 

prominent isolated subcentral tubercle. In dorsal 

view, three knobs stand out: subcentral tubercle, 

posterodorsal tubercle, and terminal ala.

Description. The description for Hermanites sp. 

by Holden (1967) applies here.

Types and dimensions. 

Paratype

USNM 184477. 

Paratype

USNM 184478. 

Holotype

USNM 184479. 

Paratype

UCB 40546.

Depth (m) L H W

Adult carapace ______R-300.59 568 323 273

Adult carapace ______S-91.14 580 337 297

Adult LV __________S-91.14 584 335 169

Adult carapace ____R-306.32 500 298 243

Distribution. Pleistocene(?): Sand Island hole 

(3). Lower Miocene: reef hole (5).

Species No. S(25), R(42).

Discussion. This species was originally described 

from drowned terraces of late Cenozoic age around 

the Hawaiian Islands (Holden, 1967).

The species is derived from Hermanites praehawaiianensis in the lower Miocene. Specimens of 

both species occur in R-306.32 m, but are poor examples, as they show transitional characters. Closely related to H. hornibrooki (Puri), late Miocene to 

Holocene, in the Caribbean (see Bold, 1968), but has 

a blunter posterior, more evenly developed alae, and 

an irregular dorsolateral riblet. The Midway and 

Hawaiian species is also larger.

Hermanites praehawaiianensis Holden, n. sp.

Plate 5, figures 10-12, 14-16

Diagnosis. Dorsal margin slightly rounded; alae 

poorly developed, nonextended; surfaces randomly 

and sparsely pitted; posterodorsal to ala ridge absent ; otherwise like H. hawaiianensis.

Description. In lateral view: carapace subquadrate; anterior slightly obliquely rounded with many 

small denticals near valve edge; posterior subtruncate; dorsum gently rounded; venter straight; subcentral and posterodorsal tubercles prominent; alae 

weak; surfaces having large random sparse pits; 

oblique dorsolateral riblet extending to dorsum. In 

dorsal view: anterior and posterior blunt; greatest 

width at subcentral tubercles; posterodorsal tubercles also extended; alae barely visible or imperceptible. Internal features not observed. 

Types and dimensions. 

Paratype

USNM 184480. 

Paratype

USNM 184481. 

Paratype

USNM 184482. 

Holotype

USNM 184483. 

Paratype

USNM 184484. 

Paratype

USNM 184485 

Paratype

UCB 40547.

Depth (m) L H W

Adult carapace ____--R-343.30 584 318 277

Adult carapace ______R-343.30 582 333 257

Adult carapace ____---R-343.30 601 356 283

Adult carapace ______R-321.87 600 350 283

Adult carapace ______R-336.27 632 352 274

Adult carapace ---___R-311.35 572 322 267

Adult carapace __--_R-320.35 498 290 225

Distribution. Lower Miocene: reef hole (105). 

Species No. R(67).

Discussion. This species is closely related to 

Hermanites tosaensis (Ishizaki, 1968, 1969), living 

species in southern Japan. The two species are similar in side view except that H. praehawaiianensis 

lacks the stout vertical subocular ridge and the connecting ridge between the posterocardinal angle and 

posterior part of the ventral ridge. Dorsal comparisons could not be made.

Hermanites praehawaiianensis lived early at Midway, being first found at R-336.96 m, but quickly 

evolved into H. hawaiianensis which is first recognized at R-306.32 m, also in the lower Miocene, and 

was still present in the post-Miocene (Pleistocene) 

at S-73.46 m. Presumably H. praehawaiianensis 

came from the Asian coast where the closely related 

H. tosaensis still lives.

Hermanites tschoppi (Bold)

Plate 4, figures 6-9, 15; plate 12, figure 5; plate 13, figures 3, 4

Cythereis tschoppi Bold, 1946, Amsterdam, p. 93 (part), pi. 

10, figs. 14a, b.

Her mania reticulata Puri, 1954, Florida Geol. Survey Bull. 

36, p. 267, pi. 11, figs. 8, 9, text-figs, g, h.

Hermanites haidingeri (Reuss). Bold, 1957, Micropaleontology, 

v. 3, no. 3, p. 239, pi. 2, figs, la, b (not Cypridina haidingeri Reuss, 1850).

Hermanites sp. aff. H. paijenborchiana Keij. Bold, 1960, Micropaleontology, v. 6, no. 2, p. 170, pi. 8, fig. 10.

Hermanites fungosa Butler, 1963, Louisiana Geol. Survey 

Geol. Bull. 39, p. 63, pi. 4, figs. 4-6.

Hermanites tschoppi (Bold). Bold, 1965, Micropaleontology, 

v. 4, no. 1, p. 398, pi. 6, figs. 2a, b.
F28 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184486. Adulttf LV _______S-141.73 711 369 183 

Hypotype

USNM 184487. Adult? carapace ____S-147.37 685 390 360 

Hypotype

USNM 184488. Adult? LV _______R-344.37 374 362 146 

Hypotype

USNM 184489. Adulttf RV ___.___R-296.66 779 367 165 

Hypotype

USNM 184490. Adult? LV ________R-296.66 742 403 233 

Hypotype

USNM 184491. Adult? RV ________R-173.28 725 417 235

Distribution. Upper Miocene: Sand Island hole 

(103) ; reef hole (7). Lower Miocene: reef hole 

(75).

Species No. S (54), R (28).

Discussion. A very wide ranging species known 

from the middle Tertiary of the Florida gulf coast, 

and throughout the Caribbean. Quite possibly the 

Eocene Hermanites paijenborchiana of Belgium is 

conspecific.

In some specimens the ventral ala of the right 

valve is incompletely formed, and the posterior part 

of it is left stranded as a vertically oriented flangelike tubercle. (See for instance pi. 4, fig. 9.) These 

individuals usually occur with the normal types, 

and thus this feature must be considered intraspecific variation. The weak submedian ridge occurring in the type specimen mentioned by Bold (1965) 

is poorly developed in the late Miocene Midway individuals.

Hermanites sp. aff. H. barn (Bold, 1960)

Plate 4, figure 24; plate 12, figure 21

Types and dimensions. 

Specimen

USNM 184493. 

Specimen

UCB 40549.

Depth (m) L H W

Adult RV .________S-148.74 962 558 275

Adult RV _________R-338.94 998 610 280

Distribution. Upper Miocene: Sand Island hole 

(1). Lower Miocene: reef hole (1).

Species No. S(59), R(96).

Discussion. Only one poorly preserved right 

valve found. Though it has the same basic morphology as Bold's late Eocene Caribbean Costa 

barri (Bold, 1960), no definite taxonomic assignment can be given the specimen.

Genus CLETOCYTHEREIS Swain, 1963 

Cletocythereis bradyi Holden, 1967

Plate 4, figure 13

Cythere rastromarginata Brady, 1880, Kept. * * * Voyage * * * 

Challenger, Zoology, v. 1, p. 83, pi. 16, figs. 2a-d; not 

fig. la-c. 

Cletocythereis bradyi Holden, 1967, Pacific Sci., v. 21, no. 1,

p. 40, text-figs. 31a-c.

Ishizaki, 1968, Tohoku Univ. Sci. Repts., ser. 2 (Geology), v. 40, no. 1, p. 40, pi. 8, fig. 9.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184492. Adult? carapace ____S-44.20 667 325 340 

Hypotype

UCB 40648. Adulttf LV ________S-91.14 672 335 199

Distribution. Pleistocene (?): Sand Island hole 

(20).

Species No. S(12).

Discussion. This species differs from Hermanites 

tschoppi by having a perfect dorsal ridge running 

from the posterodorsum to the eye tubercle instead 

of one that dips down toward the midlateral region, and by having a wider anteromarginal rim. 

Very probably Cletocythereis bradyi evolved from 

Hermanites tschoppi in the early post-Miocene.

Genus HAMMATOCYTHERE Keen, 1972 

Hammatocythere ? sebastianensis (Bold)

Plate 3, figures 1-4,16; plate 12, figures 1-4

"Cythereis" sebastianensis Bold, 1965, Micropaleontology, 

v. 11, no. 4, p. 399, pi. 6, figs. 3a, b; pi. 7, figs. 6a, b.

Types and dimensions. 

Hypotype

USNM 184503. 

Hypotype

USNM 184504. 

Hypotype

USNM 184505. 

Hypotype

USNM 184506. 

Hypotype

USNM 184507. 

Hypotype

USNM 184508.

Depth (m) L H W

Adult RV _________R-296.66 667 365 137

Adult LV __-.____R-318.67 689 393 170

Adult RV _________R-318.67 674 374 163

Adult carapace ______R-318.67 697 400 350

Adult carapace __...R-296.66 616 366 275

Adult LV __________R-318.67 650 370 162

Distribution. Lower Miocene: reef hole (about 

390).

Species No. R(48).

Discussion. The species is extremely abundant in 

the interval between R-317.37 m and 318.82 m in 

fauna R-, accounting for as much as 75 percent of 

the ostracode fauna.

In the original description (Bold, 1965), muscle 

scars were not reported. On the Midway specimens 

they are well preserved, the adductors consisting of 

a row of four narrow elongate scars on the side of 

a deep subcentral depression with two frontal scars 

within the depression (pi. 12, fig. 3). Radial pore 

canals are moderately abundant, unbranched, sinuous, and have median enlargements.

The species is questionably assigned to Hammatocythere because of atypical radial pore canals and 

the unusually thin shell of most specimens. However, general shape, ornamentation, and other internal features are typical of the genus. Hammatocythere was originally described from the lower and 

middle Oligocene of Europe (Keen, 1972).

Family TRACHYLEBERIDIDAE Sylvester-Bradley

Subfamily TRACHYLEBERIDINAE Sylvester-Bradley

Genus NEOCAUDITES Puri, 1960

Neocaudites sp. 

Plate 12, figures 18, 19

Types and dimensions. 

Specimen

USNM 184501. 

Specimen

USNM 184502. 

Specimen

UCB 40653.

Depth (m) L H W

Adult carapace _____R-307.39 586 240 242

Adult can-apace _____R-307.39 569 317 234

Adult carapace _____R-307.39 525 283 200
LATE CENOZOIC OSTRACODA F29

Distribution. Lower Miocene: reef hole (4).

Species No. R (68).

Discussion. This form is similar to Rectotrachyleberis edwardsii (Miocene, Europe) in that both 

have a long midlateral ridge that goes beyond the 

subcentral area almost to the anterior margin. Also, 

both species are smooth between the prominent 

ridges.

Neocaudites terryi Holden

Neocaudites terryi Holden, 1967, Pacific Sci., v. 21, no. 1, p. 

43, 44, text-figs. 33a-d.

Types and dimensions. 

Hypotype

USNM 184494. 

Hypotype

UCB 40550.

Depth (m) L 'H W

Adultd" carapace ____S-140,67 461 225 134

Adult? LV .._____S-140.21 448 237 83

Distribution. Upper Miocene: Sand Island hole 

(2).

Species No. S (47).

Discussion. The specimens are smaller but otherwise identical with the fossil specimens of Holden 

(1967) from Hawaii.

Genus OCCULTOCYTHEREIS Howe, 1951 

Occultocythereis sp.

Plate 12, figures 22, 23 

Types and dimensions. 

Specimen

USNM 184495. 

Specimen

USNM 184496. 

Specimen

UCB 40551.

Depth (m) L H W

Adult carapace ____R-283.46 495 248 180

Adult carapace _____R-295.81 510 267 205

Adult carapace ____R-283.46 501 248 205

Distribution. Lower Miocene: reef hole (8).

Species No. R(49).

Discussion. This species differs from most other 

species of Occultocythereis by having a pointed 

caudal process with ventral spines close to the terminal part. The marginal rims are narrow, and the 

carapace is moderately inflated in the alar region.

Genus PLATYCOSTA Holden, 1964

Platycosta amicus Holden, n. sp. 

Plate 4, figures 16, 17; plate 13, figures 1, 2

Diagnosis. Small fine reticulations, faint midlateral ridge from posterodorsum to subcentral 

tubercle; posterior right-valve tooth entire.

Description. Small, surfaces finely reticulate; 

males longer than females. Lateral view: doTsum 

and venter straight, slightly converging posteriorly; 

anterior broadly and evenly rounded; posterior 

bluntly pointed at midheight, concave in dorsal half; 

small smooth subcentral tubercle, faint smooth ridge 

between it and posterodorsal tubercle; brief swelling 

along midventrolateral area; prominent continuous 

rim along anterior, ventral, and posterior margins,

sometimes broken by large flangelike spines in posteroventer; about eight large spines along anterior 

edge, some of which coalesce to outer marginal 

ridge. Dorsal view: compressed; greatest width behind middle at ventral midlateral swelling; terminally blunt, anteroventrum often massive and wide.

Hinge holamphidont. Nonvestibulate duplicature 

wide; radial pore canals large, often bifurcating, 

some with midswellings; normal pores small. Four 

adductor scars; U-shaped frontal scar.

Types and dimensions. 

Paratype

USNM 184497. 

Holotype

USNM 184498. 

Paratype

USNM 184499. 

Paratype

USNM 184500. 

Paratype

UCB 40552.

Depth (m) L H W

Adultd1 carapace ___R-336.27 500 269 166

Adult? carapace ____R-366.27 504 272 175

Adultrf carapace ____R-320.35 453 223 16i<

Adultd" RV ________S-45.11 483 232 102

Adultrf carapace ____R-320.35 421 226 166

Distribution. Pleistocene(?) : Sand Island hole 

(1). Lower Miocene: reef hole (47).

Species No. S(20), R (55).

Discussion. This is the second known species of 

the genus Platycosta. The type species occurs in the 

Upper Cretaceous of southern California and Baja 

California (Holden, 1964, 1970).

Name. amicus (L.) = friend.

Family CYTHERIDEIDAE Sars, 1925

Subfamily CYTHERIDEINAE Sars, 1925

Genus CYPRIDEIS Jones, 1857

Cyprideis beaconensis (LeRoy)

Plate 6, figures 21-23; plate 13, figures 5-7 

Cytheridea beaconensis LeRoy, 1943, Jour. Paleontology v.

17, no. 4, p. 359, pi. 58, figs. 21-25, text-fig. 2c. 

Cyprideis (Goerlichia) stewarti Benson, 1959, Kansas, Univ.

Paleont. Contr., Arthropoda, Art. 1, p. 45, pi. 2, figs.

2a, b; pi. 9, figs. 17. 

Cyprideis (Goerlichia) miguelensis Benson, 1959, Kansas

Univ. Paleont. Contr., Arthropoda, Art. 1, p. 45, 46, pi.

2, figs. 3a, b; 1. 9, fig. 16. 

Cyprideis (Goerlichia) sp. Benson, 1959, Kansas Univ.

Paleont. Contr., Arthropoda, Art. 1, p. 46, 47, pi. 2, figs.

5a, b; pi. 9, figs. 13, 15. 

Cyprideis lengae Hartmann, 1961, Zeitschr. Wiss. Zoologie, v.

165, p. 428-452, figs. 3-24. 

Hartmann, 1962, Hamburg. Zool. Mus. Inst., Mitt., v.

60, p. 36, 194. 

Cyprideis beaconensis LeRoy. Sandberg, 1964, Stockholm

Contr. Geology, v. 12, p. 95-100, pi. 4, figs. 11-13; pi.

5, figs. 1-12; pi. 17, figs. 2a, b; pi. 19, figs. 7, 8; pi. 20,

figs. 3, 4; pi. 21, figs, la-c; pi. 22, figs. 7a, b. 

Resig, 1969, Hawaii Inst. Geophysics, HIG-69-2, p. 24,

pi. 9, figs. 13-19.

Types and dimensions. 

Hypotype

USNM 184509. 

Hypotype

USNM 184510. 

Hypotype

USNM 184511. 

Hypotype

UCB 40554. 

Hypotype

UCB 40555.

Depth (m) L H W

Adult? RV ________S-78.49 936 520 249

Adultc? RV ________S-74.22 950 484 203

Adult? LV ________S-78.49 899 520 235

Adultc? RV __-.--_.S-73.91 922 484 194

Adult? LV ________S-73.91 903 517 273
F30 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Distribution. Pleistocene(?): Sand Island hole 

(110).

Species No. S(13).

Discussion. This brackish-water species occurs 

in great abundance in fauna S3 together with an 

otherwise normal marine assemblage. The lack of 

tubercles on any of the specimens is an additional 

indication that salinity was not much below normal. 

As pointed out by Resig (1969) for the Pleistocene 

occurrence of the species on Oahu, Hawaii, the environment was probably an open lagoon locally 

freshened by stream runoff rather than a closed lagoon that became fresh.

The species is known only from the Pleistocene 

and Holocene.

Family CYTHERURIDAE Muller, 1894 

Subfamily CYTHERURINAE Muller, 1894 

Genus SEMICYTHERURA Waguer, 1957

Semicytherura sp.

Plate 13, figures 8, 9

Types and dimensions. 

Specimen

USNM 184512. 

Specimen

UCB 40556.

Depth (m)

Adult carapace --._--R-320.95 

Adult carapace ____.R-321.72

L H W

342 190 189

342 183 208

Distribution. Upper Miocene: Sand Island hole 

(1). Lower Miocene: reef hole (2). 

Species No. <S(35), R(77).

Genus HEMICYTHERURA Elofson, 1941 

Hemicytherura pentagona Hornibrook

Plate 13, figures 13, 14

Hemicytherura pentagona Hornibrook, 1952, New Zealand

Geol. Survey Palaeont. Bull. 18, p. 59, pi. 13, figs. 202-

205, 211. 

Hemicytherura cuneata Hanai, 1957, Tokyo Univ. Fac. Sci.

Jour., sec. 2, v. 11, pt. 1, p. 24, 25, pi. 2, figs. 2a, b;

text-figs, la, b. 

Ishizaki, 1966, Tohoku Univ. Sci. Repts. ser. 2 (Geology),

v. 37, no. 2, p. 140, pi. 18, figs. 22, 23.

Types and dimensions. 

Hypo type

USNM 184513. 

Hypotype

USNM 184514. 

Hypotype

UCB 40557.

Depth (m) L H W

Adult carapace _____S-140.21 325 200 166

Adult carapace ___S-140.67 302 142 150

Adult carapace ______S-135.64 315 193 163

Distribution. Upper Miocene: Sand Island hole 

(3).

Species No. -S (36), R (38).

Discussion. Hanai stated that his Japanese species shows only minor ornamental differences when 

compared with H. pentagona and that therefore the 

two are closely related. Minor differences occur between the Midway specimens and those from Japan 

and New Zealand, not the least of which is the Midway specimen's lack of faint reticulations between

the major ridges (poor preservation?). Regardless, 

they appear to be assignable to the same species. 

Hanai (1957) and Hornibrook (1952) reported it as 

Holocene. The species is also known from the lower 

Miocene of Japan (Ishizaki, 1966).

Family BYTHOCYTHERIDAE Sars, 1926 

Genus BYTHOCERATINA Hornibrook, 1953

Bythoceratina sp.

Plate 13, figures 10-12

Type and dimensions. Specimen USNM 184515. 

Adult RV. S-45.11 m. L=380+ (broken), #=192, 

W=IS2.

Distribution. Pleistocene (?) : Sand Island hole

(1). 

Species No. S(23).

Family PARACYTHERIDEIDAE Puri, 1957

Subfamily PARACYTHER1DEINAE Puri, 1957

Genus PARACYTHERIDEA Muller, 1894

Paracytheridea sp. 

Plate 13, figures 18, 19

Types and dimensions.-

Specimen

USNM 184516. 

Specimen

USNM 184517. 

Specimen

UCB 40558. 

Specimen

UCB 40559.

Depth (m)

Adult LV _________R-320.50 

Adult LV _________R-320.35 

Adult LV _________R-320.04 

Adult RV _________R-320.95

L H W

502 243 203

483 250 216

508 249 202

502 207 215

Distribution. Lower Miocene: reef hole (8).

Species No. R(78).

Discussion. The species has some resemblance to 

the Holocene Paracytheridea tschoppi (Bold, 1946) 

but is relatively unornamented on the anterior swelling. It is also very similar to P. sp. of Hazel and 

Holden (1971) from the Eocene of Tonga but has 

less of an alar spine and better developed ridges in 

the posterodorsum.

Family KRITHIDAE Sars, 1925

Subfamily KR1THINAE Mandelstam, 1958

Genus PARAKRITHELLA Hanai, 1961

Parakrithella robusta Holden, n. sp.

Plate 6, figures 14-17; plate 13, figures 15-17

Diagnosis. Highest in posterior half; dorsum almost straight, sloping down to evenly rounded anterior margin; broad anterior vestibule, venter 

straight.

Description. Dimorphism present with inferred 

g being longer and posteriorly inflated; carapace 

heavy, semitransparent. Lateral view: dorsum highly arched in posterior half, flattened in anterior 

half; anterior evenly rounded; venter straight; 

posterior broadly rounded to dorsal high point; surfaces smooth. Dorsal view: greatest width in posterior third ( $ ) to about at midlength ( $ ) ; ends 

bluntly pointed.
LATE CENOZOIC OSTRACODA F31

Right-valve dorsal margin fits into groove of left 

valve; groove faintly crenulate toward posterior 

part with corresponding crenulations in left-valve 

dorsum. Large anterior vestibule; radial pore canals 

sparse, about 11 anteriorly, large, tending to branch 

near margins; normal pores sparse, forming deep 

pits internally. Four adductor scars; one frontal 

scar, always with large normal pore just above and 

below.

Types and dimensions. 

Para type

USNM 184518. 

Paratype

USNM 184519. 

Hodotype

USNM 184520. 

Paratype

USNM 184521. 

Paratype

USNM 184522. 

Paratype

UCB 40560.

Depth (m) L H W

Adulttf LV -- S-141.73 682 370 170

Adult? RV -S-141.73 683 333 138

Adult? carapace ____S-140.67 701 366 300

Adultcf carapace -__....S-140.67 708 367 306

Adultcf LV ------____S-140.21 692 355 173

Adultcf LV ______--S-140.21 680 370 175

Distribution. Upper Miocene: Sand Island hole 

(825) ; reef hole (73).

Species No. S (48), R (22).

Discussion. The genus is known only from Japan 

(Hanai, 1959, 1961; Ishizaki, 1968, 1971) and from 

the Pliocene-Pleistocene (?) of Okinawa (Hanai, 

1959) with the single species Parakrithella pseudadonta. It is noteworthy that the Japanese species is 

found only in shallow water. The fauna accompanying P. robusta also indicates a shallow-water preference.

Parakrithella eopacifica Holden, n. sp. 

Plate 17, figures 15-19

Diagnosis. Carapace small, suboblong, thin 

shelled; dimorphic with posteriorly arched inferred 

males; inturned area concave; posterior bluntly 

pointed.

Description. Lateral view: inferred males posteriorly arched; females more evenly arched or dorsally flat; ventral margin sinuous, broadly rounded 

in posterior half, concave at inturned area; posterior 

bluntly pointed in ventral half; left valve overlapping right valve along all margins. Dorsal view: 

greatest width at midlength and midheight; anterior sharply pointed; posterior rounded.

Right-valve dorsum fitting into groove of left 

valve; short section faintly crenulate in posterior 

half of right-valve dorsum with corresponding 

crenulations in left valve. Anterior duplicature wide 

with deep vestibule branching about five times into 

large radial pore canals. Radial pore canals large, 

often branching twice or thrice near margins. 

Normal pores large, sparse, apparently sieve type. 

Four elongate large adductor scars.

Types and dimensions. 

Holotype

USNM 184523. 

Paratype

USNM 184524. 

Paratype

USNM 184525. 

Paratype

USNM 184526. 

Paratype

UCB 40561.

Depth (m) L H W

Adultc? RV ________R-319.21 450 218 102

Adult? carapace ____-R-320.95 452 210 172

Adultcf carapace ____R-320.95 483 233 186

Adult? carapace ____R-288.65 560 557 207

Adultc? carapace _____R-283.46 503 233 200

Distribution. Lower Miocene: reef hole (290).

Species No. R(40).

Discussion. The major differences between this 

species and Parakrithella robusta are size and 

heaviness of shell. Parakrithella robusta is 680 to 

710 p long and thick shelled, whereas P. eopacifica 

is typically 450 to 480 /* long and fragile. In the 

upper part of its range, P. eopacifica gradually increases in size and at about 280 m in the reef hole 

is 500 to 560 p. long. Most probably this species gives 

rise to P. robusta, but the section containing the 

transitional forms is missing.

Family LEPTOCYTHERIDAE Hanai, 1961 

Genus CALLISTOCYTHERE Ruggieri, 1953

Callistocythere crenata (Brady) 

Plate 14, figures 1, 2

Cythere crispata Brady. Brady, 1880, Kept. * * * Voyage * * * 

Challenger, Zoology, v. 1, p. 72, 73, pi. 14, figs. 8a-d.

Cythere crenata Brady, 1890, Royal Soc. Edinburgh Trans., 

v. 35, p. 497, 498, pi. 2, figs. 35, 36.

Callistocythere aff. crispata (Brady). Apostolescu, 1967, Paris, 

Editions Fond. Singer-Polignac, pi. 2, figs. 50-52.

Types and dimensions.-

Hypotyp«

USNM 184527. 

Hypotype

USNM 184528. 

Hypotype

UCB 40562.

Depth (m)

Adult LV ________S-44.20 

Adult RV __________S-44.20 

Adult LV ________S-78.88

L H W

365 210 98

350 201 83

433 245 92

Distribution. Pleistocene (?): Sand Island hole 

(3). Lower Miocene: reef hole (3).

Species No. S (14), R (79).

Discussion. These specimens are identical with 

Holocene specimens from New Hebrides and Fiji. 

The species is also known from Hong Kong, Booby 

Island (near Torres Straits), and Port Jackson, 

Australia (Brady, 1880), and New Caledonia 

(Apostolescu, 1967). The Midway specimens are 

somewhat variable in ornamentation. In some specimens, certain lateral ridges are accentuated. (See 

pi. 14, fig. 2.)

Callistocythere sp. 1 

Plate 13, figures 20, 21

Types and dimensions. 

Specimen

USNM 184529. 

Specimen

USNM 184530.

Depth (m)

Adult LV ________.-S-147.37 

Adult RV .-___--.-.__.S-147.37

L H W

450 222 118

448 225 98
F32 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Distribution. Upper Miocene: Sand Island hole 

(2). 

Species No. S(60).

Callistocythere sp. 2

Plate 14, figures 7, 8

Type and dimensions. Specimen USNM 184531. 

Adult carapace. R-320.95 m. L=400, #=201, W= 

133.

Distribution. Lower Miocene: reef hole (1).

Species No. R(80).

Family LOXOCONCHIDAE Sars, 1925 

Genus LOXOCONCHA Sars, 1865

Loxoconcha longispina Key

Plate 4, figure 14; plate 5, figures 3-6; plate 14, figures 12-15

Loxoconcha alata Brady, 1880, Rept. * * * Voyage * * * Challenger, Zoology, v. 1, pt. 3, p. 122, pi. 27, figs. 6a-j 

(not Brady, 1868).

Loxoconcha alata Brady var. longispina Key, 1953, Kon. 

Nederlandse Akad. Wetensch., ser. B, v. 56, pt. 2, p. 

160, pi. 1, figs. lOa, b.

Loxoconcha longispina Key. Holden, 1967, Pacific Sci., v. 21, 

no. 1, p. 32-24, figs. 23a-d.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184532. Adultd1 LV ________S-78.88 584 316 192 

Hypotype

USNM 184533. Adultd RV ________S-78.88 579 332 154 

Hypotype

USNM 184534. Young LV ________ S-78.88 416 234 140 

Hypotype

USNM 184535. Adult? RV _________S-79.19 521 440 166 

Hypotype

USNM 184536. Adult? carapace __ S-79.19 536 317 317 

Hypotype

USNM 184537. Adultcf LV ________S-147.37 486 249 170 

Hypotype

USNM 184538. Adultcf carapace __.j-S-147.37 490 230 294 

Hypotype

UCB 40563. Adultcf carapace _____ S-79.19 584 334 314 

Hypotype

UCB 40564. Adult? LV ________S-147.37 450 252 167

Distribution. Pleistocene (?) : Sand Island Role 

(135) ; reef hole (55). Upper Miocene: Sand Island 

hole (5). Lower Miocene: reef hole (17). PostMiocene : reef hole (2).

Species No. S(2),R(4).

Discussion. The Pleistocene (?) specimens are 

not as strongly alate as others reported from the 

tropical Pacific, but the early and late Miocene 

specimens 'are.

The species is variable; two forms are represented. The majority are the larger but relatively 

shorter forms represented on plate 5, figures 3-6, 

and plate 14, figures 12-14. The smaller and relatively longer form occurs near the bottom of both 

holes but is not found mixed with the larger form.

Loxoconcha antillea Bold sensu stricto

Plate 4, figures 10,11; plate 5, figures 1, 2; plate 14, 

figures 4-6, 17

Loxoconcha antillea Bold, 1946, Amsterdam, p. 110, pi. 15, figs. 

3a-c.

Bold, 1965, Micropaleontology, v. 11, no. 4, p. 402, pi. 4,

figs. 3a-c.

Loxoconcha fischeri (Brady). Bold, 1957, Micropaleontology, 

v. 3, no. 3, p. 244, pi. 2, fig. 7 (not L. fischeri (Brady)).

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184539. Adultcf LV ____ __ R-161.39 546 296 136 

Hypotype

USNM 184540. Adult? LV ________S-141.73 464 271 140 

Hypotype

USNM 184541. Adult? carapace ____R-283.46 518 285 278 

Hypotype

USNM 184542. Adult? LV ________S-140.21 518 301 165 

Hypotype

USNM 184543. Adultcf LV ________ S-141.73 526 276 131 

Hypotype

USNM 184544. Adult? carapace ____S-140.21 493 280 329 

Hypotype

USNM 184545. Adultcf carapace ___ S-140.21 552 287 240

Distribution. Upper Miocene: Sand Island hole 

(65); reef hole (20). Lower Miocene: reef hole 

(46).

Species No. S (37), R (29).

Discussion. The species is widespread in the 

Caribbean Miocene. At Midway it is very abundant 

in the upper and lower Miocene samples.

In two upper Miocene samples (S-140.21 m and 

S-141.73 m) it shows variation, most of the individuals being inflated and having a smooth knoblike ala ( ? ). In the lower Miocene (greater than 

300-m depth), a new subspecies is found that lacks 

the horizontally alined reticulations and anterolateral ridges. This new subspecies, L. antillea diffusia, and L. antillea s.s. are mutually exclusive.

Loxoconcha antillea Bold diffusia Holden, n. subsp.

Plate 4, figures 18-21; plate 14, figure 3 

Diagnosis. Like L. antillea s.s., but lacking 

double horizontal anterolateral ridge, and having 

evenly developed reticulations and weak tubercles. 

Types and dimensions. 

Depth (m) L H W

Adult? carapace ____R-318.52 471 256 233

Adultd1 carapace ____R-343.30 567 303 226

Adult? carapace ____R-343.30 483 269 232

Adultd1 carapace ____R-343.30 616 292 230

Adultd LV ________R-318.52 527 252 117

Distribution. Lower Miocene: reef hole (31).

Species No. R(70).

Discussion. See Loxoconcha antillea s.s. for a 

discussion of the subspecies. Named for its diffused 

and random pattern of reticulations.

Loxoconcha uranouchiensis Ishizaki

Plate 4, figure 12; plate 14, figures 9-11

Loxoconcha uranouchiensis Ishizaki, 1968, Tohoku Univ. Sci.

Repts. ser. 2 (Geology), v. 40, no. 1, p. 32, pi. 7, figs.

2,3. 

Ishizaki, 1971, Tohoku Univ. Sci. Repts., ser. 2 (Geology),

v. 43, no. 1, p. 87, pi. 3, fig. 17. 

Loxoconcha sp. 2. Resig, 1969, Hawaii Inst. Geophys., HIG69-2, pi. 9, fig. 5.

Holotype

USNM 184546. 

Para type

USNM 184547. 

Paratype

USNM 184548. 

Paratype

USNM 184549. 

Paratype

USNM 184550.
LATE CENOZOIC OSTRACODA F33

Types and dimensions. 

Hypotype

USNM 184551. 

Hypotypie

USNM 184552. 

Hypotype

USNM 184553. 

Hypotypie

USNM 184554. 

Hypotype

UCB 40565.

Depth (m) L H W

Adult? LV ________S-45.11 470 243 134

Adult? LV ________S-44.20 458 2T3 166

Adultcf carapace ____S-73.47 532 267 277

Adult? RV ________S-78.88 482 283 133

AdultcT carapace ____S-85.19 524 282 249

Distribution. Pleistocene (?): Sand Island hole 

(73); reef hole (9).

Species No. S(15), R (19).

Discussion. The known geographic range of living members of the species is from northern to 

southern Honshu, Japan. The fossil specimens, including those of Resig from the Pleistocene of 

Hawaii (Resig, 1969), differ from the living Japanese specimens, as illustrated by Ishizaki (1968, 

1971), by having interruptions on the lateral ridges 

that define the reticula. On some specimens this 

gives the surface a random texture of pillars, incomplete ridges, and some reticulations. On others, 

however, reticulations dominate.

Loxoconcha sp. 1

Plate 14, figures 18-20

Types and dimensions. 

Specimen

USNM 184555. 

Specimen

USNM 184556.

Depth (m)

Adult? LV _._____S-44.20 

Adultcf RV _____S-73.46

L H W

389 225 116

426 233 103

Distribution. Pleistocene (?): Sand Island hole 

(3).

Species No. S(16).

Discussion. Possibly a descendant of L. antillea, 

which is last found at a depth of S-135.94 m. Loxoconcha sp. 1 differs from L. antillea in two ways: 

(1) The two horizontal anterolateral ridges of L. 

antillea, divided by one or two reticula, are divided 

by three to four in L. sp. 1; (2) the posterior 

tubercle, situated between the ala and posterodorsal 

tubercles in L. antillea, is fused to the posterodorsal 

tubercle in L. sp. 1.

Loxoconcha sp. 2

Plate 5, figures 7-9

Types and dimensions. 

Depth (m) L H W 

Specimen

USNM 184557. Adult carapace ____.R-355.09 450 263 250 

Specimen

USNM 184558. Adult carapace ____..R-355.09 435 253 266 

Specimen

USNM 184559. Adult carapace -------.R-355.09 473 273 257

Distribution. Lower Miocene: reef hole (4). 

Species No. 11(98).

Genus LOXOCONCHELLA Triebel, 1954 

Loxoconchella honoluliensis (Brady)

Plate 6, figures 18-20

Loxoconcha honoluliensis Brady, 1880, Kept. * * * Voyage * * * 

Challenger, Zoology, v. 1, pt. 3, p. 118, pi. 28, figs. 

6a-f.

Loxoconchella honoluliensis (Brady). Triebel, 1954, Senckenbergiana Lethaea, v. 85, p. 19, pi. 1, figs. 1-6.

Holden, 1967, Pacific Sci., v. 21, no. 1, p. 34, figs. 24a-b.

Apostolescu, 1967, Paris, Editions Fond. Singer-Polignac, 

pi. 2, figs. 29-31.

Types and dimensions. 

Depth (m) 

Hypotype

USNM 184560. 

Hypotype

USNM 184561. 

Hypotype

USNM 184562. 

Hypotype

UCB 40566.

Admit RV _________S-147.37 

Adult RV ________R-173.29 

Adult carapace --.__S-149.66 

Adult LV _________R-283.46

L H W

614 400 169

567 375 181

653 446 316

650 433 160

Distribution. Upper Miocene: Sand Island hole 

(30) ; reef hole (8). Lower Miocene: reef hole (26).

Species No. S (49), R (23).

Discussion. No differences can be observed between the early Miocene, late Miocene, and Holocene 

specimens from elsewhere in the Pacific.

Loxoconchella anomala (Brady)

Plate 6, figure 13

Loxoconcha anomala Brady, 1880, Rept. * * * Voyage * * * 

Challenger, Zoology, v. 1, p. 123, pi. 28, figs. 5a-d,

Loxoconchella anomala (Brady). Holden, 1967, Pacific Sci., 

21, no. 1, p. 34-36. 25a-f.

Types and dimensions. 

Depth (m) L H W 

Hypotype

USNM 184563. 

Hypotype

USNM 184564. 

Hypotype

UCB 40567.

Adult carapace __._..MR-21.34 584 418 373

Adult LV _________R-31.55 624 451 258

Adult LV __________S-44.20 568 406 177

Distribution. Pleistocene (?) : Sand Island hole 

(2) ; reef hole (1). Living in Midway lagoon (1). 

Species No. S (17) , R (10) .

Loxoconchella sp.

Plate 15, figures 1, 2

Type and dimensions. Specimen USNM 184565. 

Adult RV. S-140.21 m. L=468+ (broken) , #=320,

Distribution. Upper Miocene: Sand Island hole 

(1).

Species No. S(50).

Discussion. The species differs from L. anomala 

by being smooth and having a more dorsally situated 

tubercle, and from L. honoluliensis by having a 

tubercle. It may represent an ancestral form of L. 

anomala, which at Midway occurs considerably 

higher in the section.

Family PARADOXOSTOMATIDAE Brady and Norman, 1889

Subfamily PARADOXOSTOMATINAE Brady and Norman 1889

Genus PARADOXOSTOMA Fischer, 1855

Paradoxostoma romei McKenzie 

Plate 15, figures 5, 6

Paradoxostoma romei McKenzie, 1967b, Royal Soc. Victoria 

Proc., v. 80, pt. 1, no. 89, 90, figs. 4e, 8i-r.
F34 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Type and dimensions. Hypotype USNM 184566. 

Adult LV. R-31.55 m. L=534, ff=242, TF=83.

Distribution. Pleistocene (?) : reef hole (1).

Species No. R(12).

Discussion. The duplicatures and vestibule are 

identical to those of P. romei from southern Australia (McKenzie, 1967b).

Paradoxostoma sp. 1

Plate 15, figures 3, 4

Types and dimensions. 

Specimen

USNM 184567. 

Specimen

UCB 40568.

Depth (m) L H W

Adult carapace _____S-79.19 428 185 118

Adult carapace _____S-79.19 409 178 107

Distribution. Pleistocene(?): Sand Island hole 

(4). 

Species No. S(28).

Paradoxostoma sp. 2

Plate 15, figures 13, 14

Type and dimensions. Specimen USNM 184568. 

Adult LV. R-320.34 m. L=635, ff=240, TF=90. 

Distribution. Lower Miocene: reef hole (2). 

Species No. R(81).

Subfamily CYTHEROMAT1NAE Elofson, 1939 

Genus PELLUCISTOMA Coryell and Fields, 1937

Pellucistoma sp.

Plate 15, figures 7, 8

Type and dimensions. Specimen USNM 184569. 

Adult LV. R-163.6 m. L=542, H=277, TF=132 

Distribution. Upper Miocene: reef hole (1). 

Species No. R(35).

Family PECTOCYTHER1DAE Hanai, 1957 

Genus MUNSEYELLA Bold, 1957 

Munseyella inconspicua (Brady)

Plate 1, figures 14-16; plate 11, figures 3-5

Cythere inconspicua Brady, 1880, Rept. * * * Voyage * * *

Challenger, Zoology, v. 1, p. 70, 71, pi. 13, figs. la-d. 

Cythere cuneolus Brady, 1890, Royal Soc. Edinburgh Trans.,

v. 35, p. 500, pi. 2, figs. 6, 7. 

Leptocythere demissa (Brady). Key, 1954, Kon. Nederlandse

Akad. Wetensch., ser. B, v. 57, pt. 2, p. 354, pi. 1, figs.

3a,b.

Types and dimensions.-

Hypotype

USNM 184570. 

Hypotype

USNM 184571. 

Hypotype

USNM 184572. 

Hypotype

USNM 184573. 

Hypotype

USNM 184574. 

Hypotype

UCB 40569.

Depth (m)

Adult carapace .._ R-313.64

Adult carapace _____R-313.64

Adult carapace ._- R-313.64

Adult LV and RV ___S-78.88

Adult LV ________S-78.88

Adult carapace _____R-306.32

L H W

385 213 203

390 210 200

369 210 197

417 230 118

417 222 117

401 209 188

Distribution. Pleistocene (?) : Sand Island hole

(4). Upper Miocene: Sand Island hole (4) ; reef 

hole (1). Lower Miocene: reef hole (13).

Species No. S (21), R (20).

Discussion. This species was originally described 

from Torres Straits, Australia (Brady, 1880), and 

is widespread in the Pacific and Caribbean regions. 

Teeter (1966) notes the species occurs in the Great 

Barrier Reef, the Philippines, Hawaii, Qatar, the 

Bahamas, and Florida. This writer has found the 

species in Fiji, the New Hebrides, and Barbados.

The early Miocene specimens are slightly smaller, 

more wedge shaped when seen laterally, and slightly more compressed than geologically younger specimens.

Family XESTOLEBER1DAE Sars, 1928 

Genus XESTOLEBER1S Sars, 1865

Xestoleberis tumefacta Brady

Plate 16, figures 4-7

Xestoleberis tumefacta Brady, 1880 Rept. * * * Voyage * * *

Challenger, Zoology, v. 1, p. 128, 129, pi. 31, figs.

4a-d. 

Brady, 1890, Royal Soc. Edinburgh Trans., v. 35, p. 508,

pi. 3, figs. 7, 8. 

Apostolescu, 1967, Paris, Editions Fond. Singer-Polignac,

pi. 2, figs. 23-25.

Types and dimensions. 

Hypotype

USNM 184580. 

Hypotype

USNM 184581. 

Hypotype

USNM 184582. 

Hypotype

USNM 184583. 

Hypotype

UCB 40571. 

Hypotype

UCB 40572.

Depth (m)

Adult RV _________S-45.11 

Adult LV _________S-44.20 

Adult RV _________S-44.20 

Adult carapace --------S-44.20

Adult LV __-----__R-283.46

Adult carapace _____ R-283.46

L H W

518 336 183

461 315 205

470 308 150

487 331 333

560 373 224

568 375 386

Distribution. Pleistocene (?): Sand Island hole 

(58) ; reef hole (1). Lower Miocene: reef hole (9)~.

Species No. S (6), R (14).

Discussion. The early Miocene specimens differ 

morphologically from those of the post-Miocene by 

being more pointed anteriorly as seen from above 

and by being considerably larger. Living individuals 

from the southwest Pacific (Brady, 1880, 1890), 

however, are large like the early Miocene specimens 

at Midway.

Xestoleberis sp. cf. X. granulosa Brady

Plate 15, figures 9-12

Types and dimensions. 

Specimen

USNM 184584. 

Specimen

USNM 184585. 

Specimen

USNM 184586. 

Specimen

UCB 40573.

Depth (m) LEW

Adult carapace _____S-78.88 468 235 229

Adult LV _________S-78.88 440 233 117

Adult RV _________R-31.55 456 240 131

Adult RV _________R-31.55 448 223 127
LATE CENOZOIC OSTRACODA F35

Distribution. Pleistocene(?): Sand Island hole 

(7) ; reef hole (7). Lower Miocene: reef hole (14).

Species No. S (29), R (5).

Discussion. The living Xestoleberis granulosa is 

very similar to the early Miocene Midway species. 

Possibly they are conspecific. Brady's species lives 

in Bass Strait and Port Jackson (near Sydney), 

Australia (Brady, 1880), in temperate waters. 

Xestoleberis sp. B of Bold (1966a) from Panama is 

similar but has a more rounded dorsum and more 

pointed anterior.

Xestoleberis sp. cf. X. briggsi McKenzie 

Plate 16, figures 1-3

Types and dimensions. 

Specimen

USNM 184587. 

Specimen

USNM 184588. 

Specimen

USNM 184589. 

Specimen

UCB 40574.

Depth (m) L H W

Adult? carapace ...._R-320.95 388 183 227

Adult? carapace ____R-320.95 382 200 242

Adult? carapace ____R-320.95 373 186 226

Adult? carapace ____R-320.95 371 192 223

Distributon. Lower Miocene: reef hole (11).

Species No. R(82).

Discussion. Xestoleberis briggsi, from Port 

Phillip Bay, Victoria, Australia (McKenzie, 1967b), 

closely resembles this species, differing primarily 

by lacking the anteroventral notch (pi. 16, fig. 2) 

and by having a more evenly rounded dorsum. Dorsal and anterior comparisons could not be made.

Xestoleberis sp. cf. X. curta (Brady) 

Plate 15, figures 23-25; plate 17, figure 1

Types and dimensions. 

Specimen

USNM 184590. 

Specimen

USNM 184591. 

Specimen

USNM 184592. 

Specimen

UCB 40575. 

Specimen

UCB 40576.

Depth (m) L H W

Adult? LV ________S-73.46 566 336 199

Adult? RV ________S-73.46 524 300 156

Adult? carapace ____S-73.46 566 343 297

Adult? carapace ____S-97.84 532 335 308

AdultcT carapace ____S-73.45 506 291 271

Distribution. Pleistocene (?) : Sand Island hole 

(184) ; reef hole (38). Upper Miocene: Sand Island 

hole (3) ; reef hole (4). Lower Miocene: reef hole 

(160).

SpeciesNo. S(3),R(11).

Discussion. It is uncertain whether these specimens can be referred to Xestoleberis curta. X. curta 

is living on Fanning Island, Line Group, and, though 

morphologically similar, the Holocene specimens are 

smaller (380/u = $, 430/u = $ . Personal observation). It apparently occurs throughout the sequence 

at Midway.

Xestoleberis datelinensis n. sp. 

Plate 17, figures 2-6

Diagnosis. Venter straight (side view) and flatly rounded (anterior view) ; dorsum unevenly 

rounded, anteriorly flattened; radial pore canals, 

many branched in ventral half, simple in dorsal 

half.

Description. Fairly large, heavy; dimorphism 

pronounced with smaller, dorsally lenticular males, 

posteriorly inflated females. Lateral view female: 

venter straight, long; dorsum unevenly rounded with 

two faintly flattened parts posteriorly, one anteriorly; highest point at midlength. Dorsal view female: 

greatest width in posterior third; sides along midlength flattened, anteriorly converging; anterior 

pointed.

Hinge typical of genus, posterior element of right 

valve projecting, with about seven toothlets; anterior elementation elongate crenulate ridge. Anterior duplicature wide, posterior narrow and nonvestibulate; anterior vestibule deep; dorsal radial 

pore canals simple, some false; ventral ones many 

branched from deep vestibular pockets. Normal 

pores small, sparse. Muscle scars not preserved.

Types and dimensions. 

Paratype

USNM 184593. 

Holotype

USNM 184594. 

Paratype

USNM 184595. 

Paratype

UCB 40577. 

Paratype

UCB 40578.

Depth (m) L H W

Adult? carapace _._R-317.37 532 295 301

AdultcT carapace _____R-317.37 481 246 242

Adult? LV ________R-318.36 514 283 149

Adult? carapace ____R-335.74 572 324 331

AdultcT carapace ___R-335.74 548 282 285

Distribution. Lower Miocene: reef hole (230).

Species No. R(53).

Discussion. Very abundant from bottom of reef 

hole to R-284 m. Size gradually decreases from L = 

550/x at R-355 m to 530^ at 317 m to 480/x at 284 m.

The species is considered to be the direct ancestor 

of Xestoleberis sp. cf. X. curta, on the basis of 

similarities of morphology, dimorphism, and duplicature. The males of the two species are similar in 

shape, but the females have flattened sides and 

flattened venter in X. datelinensis and both are 

rounded in the other. The distinctive anteroventral 

radial pore canals persist in X. sp. of X. curta, but 

the vestibular pockets are reduced in size.

Xestoleberis sp. 1 

Plate 15, figures 19-22

Types and dimensions.-

Specimen

USNM 184596. 

Specimen

USNM 184597. 

Specimen

USNM 184598. 

Specimen

USNM 184599.

Depth (m)

Adult? LV .... S-147.37 

Adultcf LV .-- ....S-147.37 

Adult? LV __-_-S-147.37 

Adultcf RV _-.__. S-147.37

L H W

572 293 172

526 288 169

533 283 179

526 293 150

Distribution. Upper Miocene: Sand Island hole 

(40) ; reef hole (5). 

Species Afo. S(61), R(25).
F36 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Specimen

USNM 184600. 

Specimen

USNM 184601. 

Specimen

UCB 40579. 

Specimen

UCB 40580.

Discussion. The specimens are oblong in side 

view, with an evenly rounded posterior and equally 

rounded anterior. This species appears to precede 

Xestoleberis sp. 2 in the Sand Island hole and occurs 

with it at the reef hole. They are not closely related.

Xestoleberis sp. 2

Plate 15, figures 15-18

Types and dimensions. 

Depth (m) L H W

Adult LV . .._S-140.21 433 259 172

Adult RV __________S-140.21 425 __ 141

Adult LV --S-140.67 433 282 150

Adult carapace -----__R-321.86 402 244 243

Distribution Upper Miocene: Sand Island hole 

(19) ; reef hole (12)

Species No. S(38), R(17).

Discussion. A highly arched species with a somewhat pointed anterior and little or no sexual dimorphism.

Family and genus uncertain 

"Cythere" sp. aff. "C." caudata Brady

Plate 16, figures 8, 9

Types and dimensions. 

Depth (m) L H W

Adult carapace R-320.34 428 200 142

Adult carapace R-320.34 407 183 145

Adult carapace --R-336.27 422 203 149

Distribution. Lower Miocene: reef hole (4)

Species No. R(83)

Discussion. The species belongs to an undescribed genus. Other closely related species include 

Cythere caudata originally described living at Fiji 

(Brady, 1890), also living and fossil specimens from 

the Hawaiian Islands (Holden, 1967) and living specimens in Manila Bay (Key, 1954) ; "Cythere" sp. 

cf. "C." caudata living at Clipperton Island (Allison 

and Holden, 1971). The Midway specimens, unlike 

all the others so far described, are smooth. Preservation is poor, and internal features were not observed.

Ostracode sp.

Plate 16, figures 14, 15

Specimen

USNM 184575. 

Specimen

USNM 185576. 

Specimen

UCB 40570.

Types and dimensions. 

Specimen

USNM 184577. 

Specimen

USNM 184578. 

Specimen

USNM 184579.

Depth (m)

Adult carapace _._R-317.91 

Penultimate RV ____R-317.91 

3rd from last instar LV.R-317.9l

L H W

700 383 227

605 352 134

533 333 117

Distribution. Lower Miocene: reef hole R-317.91 

m (3).

Species No. R(76).

Discussion. The species appears to be a Candona,

but its identification cannot be positively determined.

Suborder PLATYCOPINA Sars, 1866

Family CYTHERELLIDAE Sars, 1866

Genus CYTHERELLA Jones, 1849

Cytherella textum Holden, n. sp.

Plate 17, figures 7-10

Diagnosis. Much elongated; posterior bluntly 

rounded; posterodorsal margin flattened, sloping; 

surfaces ornamented with fine striae.

Description. Lateral view: elongate, twice as 

long as high; venter faintly concave; anterior evenly rounded; dorsum fairly straight, flattened, and 

sloping in posterodorsal area; ornamentation of extremely fine parallel ridges generally in a concentric 

pattern everywhere except in posterior; extreme 

posterior usually has coarse pits; right valve overlap 

slight. Dorsal view: lanceolate; anterior bluntly 

pointed; greatest width in posterior third; posterior 

truncate ( $ ) to compressed behind inflation ( g ).

Central muscle-scar pattern typical of genus, in 

dorsal half just posterior to midlength.

Types and dimensions. 

Paratype

USNM 184602. 

Paratype

USNM 184603. 

Holotype

USNM 184604. 

Paratype

USNM 184605. 

Paratype

UCB 40581.

Depth (m) L H W

Adultd1 LV ________R-335.74 700 348 141

Adultd1 RV __._____-R-335.74 701 350 149

Adult? carapace ____R-284.00 810 391 327

Adultd1 carapace ____R-284.00 750 373 292

AdultcT carapace ____R-244.12 766 393 305

Distribution. Lower Miocene: reef hole (90).

Species No. R (51).

Discussion. This species is similar to Cytherella 

vanveeni from the Miocene of Guatemala, Puerto 

Rico, and Cuba (Bold, 1946, 1965), especially in 

lateral view, though that species has a heavier anterior rim and coarser ornamentation. Cytherella 

foveata from the Upper Cretaceous of south Limburg 

(Veen, 1932) also has the same general shape, but 

its sexual dimorphism is expressed differently, and 

it lacks the fine ornamental striations.

Name. textum (L.) =that which is woven; a 

web, referring to its fine ornamentation.

Cytherella sp. 1

Plate 16, figures 23, 24

Type and dimensions. "Specimen USNM 184606. 

Adult ? RV. R-288.65 m. L=766, #=412, TF=-149.

Distribution. Lower Miocene: reef hole (1).

Species No. R(56).

Discussion. The specimens are much larger than 

those of Cytherella sp. 2 and have a more rounded 

posterior and straighter dorsum. It is possibly allied 

to C. sp. a of Apostolescu (1967) from New Caledonia, but lacks the beveled posterodorsum.
LATE CENOZOIC OSTRACODA F37

Cytherella sp. 2

Plate 16, figures 10-13

Types and dimensions. 

Specimen

USNM 184607. 

Specimen

USNM 184608. 

Specimen

USNM 184609. 

Specimen

UCB 40582.

Depth (m) L H W

Adult? carapace ____S-151.79 657 385 288

Adult? RV ________S-152.25 631 366 150

Adult? LV ________S-152.25 616 352 150

Adultcf RV ..____---S-152.25 575 318 118

Distribution. Upper Miocene: Sand Island hole 

(105). Lower Miocene: reef hole (3).

Species No. S(51), R(50).

Discussion. A very common and sometimes 

abundant species from S-149 to S-152 m.

Genus CYTHERELLOIDEA Alexander, 1929 

Cytherelloidea sp. cf. C. umbonata Edwards

Plate 6, figures 5-8, 10

Types and dimensions. 

Depth (m)

Aduilt? carapace ____S-149.66 

Aduit? carapace ____R-343.30 666 372 267

601 338 223

L H W 

Specimen

USNM 184610. 

Specimen

USNM 184611. 

Specimen

USNM 184612. Adultcf carapace ____R-343.30 559 313 295 

Specimen

USNM 184613. Adultcf LV ________R-343.30 584 310 102 

Specimen

USNM 184614. Adult? RV ________S-141.73 662 384 135

Distribution. Upper Miocene: Sand Island hole 

(88). Lower Miocene: reef hole (180).

Species No. S(52), R(58).

Discussion. It is rather remarkable that the species is common and sometimes very abundant in the 

upper Miocene Sand Island hole but is completely 

lacking in the corresponding part of the reef hole. 

Cytherelloidea prefers shallow water and is rarely 

found deeper than 90 m (Sohn, 1962). In the upper 

Miocene the reef hole is considered to represent 

water about 40 m (Todd and Low, 1970) to 15 m 

(this report) deeper than that represented in the 

Sand Island hole. This difference in depth may explain the absence of any late Miocene Cytherelloidea 

in the reef hole.

Similar to Cytherelloidea umbonata from the 

upper Miocene of North Carolina (Edwards, 1944) 

in shape and ornamentation except smaller, having 

a more truncate posterior, and lacking a ridge anterior to the subcentral pit. In the Midway specimens 

the ornament varies from fine pitting to none at all. 

(See pi. 6, figs. 8, 9.)

The species has the type of hingement described 

by Bold (1963) for Cytherelloidea praecipua, C. 

semipunctata, and C. sp. 2. (See pi. 16, figs. 10, 12, 

13.)

Cytherelloidea sp. cf. C. umbonata Edwards variation

Plate 6, figure 9; plate 16, figures 17, 21 

Types and dimensions. 

Specimen

USNM 184615. 

Specimen

USNM 184616. 

Specimen

UCB 40583.

Depth (m) LEW

Adult? carapace ____R-173.28 652 385 248

Adult? LV ________R-338.94 626 303 149

Adult? RV ________R-173.28 622 355 150

Distribution. Upper Miocene: Sand Island hole 

(14). Lower Miocene: reef hole (4).

Species No. S(53), R(37).

Discussion. Similar to Cytherelloidea sp. cf. C. 

umbonata, except that the surfaces are completely 

smooth. Usually the variants are associated.

Cytherelloidea semipunctata Holden, n. sp.

Plate 6, figures 1,2; plate 16, figure 16

Diagnosis. Two sinuous lateral ridges, of which 

the top one is poorly developed; dorsal ridge paralleling lateral ridges; surfaces smooth on ridges 

and in anterolateral area, deep puncta elsewhere.

Description. Lateral view: dorsum sinuous, sloping in posterior part; venter straight; anterior 

broadly rounded with low denticles; posterior flattended ( $ ) to rounded ( $ ) ; large rounded anterior rim; two sinuous lateral ridges, top ridge 

poorly developed; sinuous dorsal ridge paralleling 

lateral ridges, connects with anteromarginal rim; 

lateral ridges connect with posterior margin via two 

circular posterior swellings ( $ ) or terminate before reaching posterior margin ( $ ) ; anterolateralmidlateral region and ridges smooth, deep circular 

pits elsewhere. Dorsal view: lanceolate, greatest 

width in extreme posterior; anterior bluntly pointed.

Hinge well developed: larger right valve strongly overlapping left valve just anterior to midlength 

with broad projecting flange; left valve with narrower tooth, just posterior to right-valve flange, fitting into distinct socket of right valve. Muscle scars 

poorly defined, on raised boss in upper half at midlength.

Types and dimensions. 

Holotype

USNM 184617. 

Paratype

USNM 184618. 

Paratype

USNM 184619. 

Panatype

USNM 184620. 

Paratype

USNM 184621.

Depth (m)

Adult? RV _______R-308.45 

Adult? LV ________R-308.45 

Adult? carapace ____R-284.74 

Adult? LV __._____R-308.45 

Adult? RV ________R-308.45

L H W

674 367 147

669 376 123

684 392 259

684 367 117

701 400 150

Distribution. Lower Miocene: reef hole R-284 to 

313 m (60).

Species No. R(52).

Discussion. This species is considered to be a 

precursor to Cytherelloidea praecipua from the Holocene of the Caribbean (Bold, 1963b) and Pacific (Allison and Holden, 1971). Cytherelloidea keiji (McKenzie, 1967b) from southern Australia is closely 

related and may be conspecific with C. praecipua.
F38 GEOLOGY OF THE MIDWAY AREA, HAWAIIAN ISLANDS

Both C. praecipua and C. keiji have the same shape, 

ridge structure, and hingement as the Midway species, but have more densely pitted surfaces.

This species is much like Cytherelloidea sp. 2, but 

has lateral ridges and very deep simple punctae.

Cytherelloidea? japonica Ishizaki 

Plate 6, figure 12; plate 16, figure 20

Ambocythere japonica Ishizaki, 1968, Tohoku Univ. Sci. Repts., 

ser. 2 (Geology), v. 40, no. 1, p. 39, pi. 2, fig. 9; pi. 8, 

figs. 15-17.

Type and dimensions. Hypotype USNM 184628. 

Adult RV. S-44.20 m. L=506, #=300, TF=133. 

Distribution. Pleistocene (?) : Sand Island hole

(1).

Species No. S(19).

Discussion. Though it has the same dimensions 

as the type figured by Ishizaki (1968), the single 

Midway specimen has no duplicature and appears to 

be immature. Also, the dorsum is broken and the 

hinge is obscure. The distinctive surface ornamentation is identical with that of the Japanese specimens.

Cytherelloidea sp. 1

Plate 6, figure 11

Type and dimensions. Specimen USNM 184622. 

Adult $ RV. S-44.20 m. L=664, #=339, TF=134. 

The single adult specimen is probably a male.

Distribution. Pleistocene (?): Sand Island hole 

(3).

Species No. S(18).

Discussion. The complete lack of longitudinal 

lateral ridges suggests Cytherella rather than Cytherelloidea. However, the deep though small pits 

and faint anterior marginal ridge is indicative of 

the genus Cytherelloidea. The single adult specimen 

is probably a male.

Cytherelloidea sp. 2 

Plate 6, figures 3, 4; plate 16, figures 18, 19

Types and dimensions. 

Specimen

USNM 184623. 

Specimen

USNM 184624. 

Specimen

USNM 184625. 

Specimen

USNM 184626.

Depth (m)

Adultcf RV ________R-318.52 

Adult? RV ________R-318.52 

Adult? carapace ____R-318.36 

AduJtcf carapace ____R-318.36

L H

650 433

668 361

W 

195 

170

686 384 260

648 367 223

Distribution. Lower Miocene: reef hole R-318.21 

to R-318.66 m (30).

Species No. R (71).

Discussion. This species is closely related to 

Cytherelloidea sp. cf. C. umbonata and possibly is a 

phenotypic variant of it. Its range is brief and coincides well with that of Patagonacy there*! sebastianensis, which usually occurs in great abundance. 

The species is distinctive, having no well-defined

lateral ridges and having rare pits of a type atypical of C. sp. cf. C. umbonata. A well-developed hinge 

like that of C. sp. cf. C. umbonata and other allied 

Midway species is present.

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INDEX

[Italic page numbers indicate descriptions and major references]

Page

Admiralty Islands ____________ Fll, 26 

aequabttis, Quadracythere .......... 24; pi. 17

Age of sediments __---_______-__-___- 10

foraminiferal data -----____ 3,4,5,9,10

Aglaiocypris ......................... 19

croneisi ----------------_-------- 20

BP _____________-______ 19; pi. 10 

alata, Loxoconcha --------_--______ 32

longispina, Loxoconcha ___________ 32

algocola, Paranesidea ________________ 17

Ambocythere japonica ................ 38

amicus, Platycosta ... ________ 29; pis. 4, 13 

Amphistegina madagascarensis ........ 9

amygdaloides, Bairdia __________-_---- 12

Anchistrocheles ....___________________ 18

sp _________________---- -- 18

anomala, Loxoconchella ____________ 33; pi. 6

antUlea, Bairdia _________.___-__------ 18

diffusia, Loxoconcha ........ 32; pis. 4, 14

Loxoconcha .. 8, 9, 10, 32, 33; pis. 4, 5, 14 

Assemblage I ____- -- 3,9,11 

Assemblage II _________ 3,5,8,9,10,11

Assemblage III ____________ 5,7,8,10,11 

Aurila --------------- __------------ 22

cicatricosa ........_-___---.__--- 21

deformis ----------......__------- 21

laevicula ....... ____------ -__- 23

lincolnensis ............ 22; pis. 2, 11, 16

sp ______--____________ 23; pi. 11 

Australia ________ - 25,34,37

B

Bahamas _-.__- ___. 

Bairdia amygdaloides 

antillea _________

bradyi __________

crosskeiana ......

crumena ........

hanaumaensis 

kauaiensis .......

ritugerda ........

truncata .........

victrix ..........

Bairdiacea ..........

Bairdiidae ... ________

Bairdiinae ___________

Bairdoppilata .......

............. 34

.________ 12 

.________ 18 

.________ 17 

.________ 11 

.________ 15 

.________ 15 

._________ 12 

._______ 12 

.________ 15 

.________ 16 

.________ 11 

._____----- 11

.________ 11 

 _______ 17 

bradyi .................... 3, 17; pis. 1, 9

planolata magnumcaudata .. _ 8, 18; p\. 9 

planolata planolata ____________ 17; pi. 9

planolata ventrocaudata ---------- 18

Baja California _____________ 15,23,29 

Barbados ------ -_-_----___--_-_ 34

barri, Costa ___-__-_---_------------__ 28

Hermanites .. -______---__ 28; pis. 4, 12

Barren intervals __-------__-__-_-_____ 9

Basement rocks _--_-_---__---_______ 1

Bass Strait, Australia -_-__------ 8,23,35

Bathyal, upper _ ----- ___________ 19

beaconensis, Cyprideis .. 3, 9, 10, 29; pis. 6, 13 

Cytheridea ........................ 29

Belgium _____-_____ 28

Page 

bicarinata, Cythereis ____-_--__--_____ F25

Jugosocythereis ................... 25

Biogeographic affinities of the faunas __ 8, 10 

Booby Island __________________ 31 

Brackish-water species ---------------- 30

Bradleya sp. a _______________________ 26

bradyi, Bairdia ....................... 17

Bairdoppilata .............. 3, 17; pis. 1,9

Cletocythereis .........__-_.__ 28; pi. 4

Triebelina ........__________ 9,15

briggsi, Xestoleberis ____________ 8, 35; pi. 16

Bythoceratina ________________________ 30

sp _____-______________ 30; pi. 13

Bythocypridinae -----_-_ _--.__-_---- 18

Bythocypris .......................... 18

compressa ........................ 18

elongata -------------------------- 18

reniformis ______________ 4, 5, 8, 18; pi. 1

Bythocytheridae ................. ______ 30

California ____________________ 23,29

calix, Pokornyella .................... 21

Callistocythere .............._________ 31

crenata _____________________ 8, 31; pi. 14

crispata .... ______________________ 31

sp. 1 -------__--._______ 31; pi. 13

sp. 2 ---- _________ 8, 32; pi. 14 

canaliculata, Jugosocythereis _-_-______ 3, 8

canaliculata,

Jugosocythereis .. 2!t; pis. 4, 12, 14

Jugosocythereis

canaliculata ____ 24; pis. 4, 12, 14

reticulata,

Jugosocythereis -------- 9,10,25;

pis. 4, 12 

Candona __---_---___________-_________ 36

Caribbean _____ 10,11,16,17,20,21,23,25,

27, 28, 32, 34, 37

cassida, Ne&nesidea ________ 7, 8, 10, 11; pi. 7

caudata, Cythcre .................. 36; pi. 16

Caudites .............................. 20

spp . ____._._ _ 20; pis. 1, 10 

cicatricosa., Aurila ____________________ 21

Cletocythereis ......................... 28

bradyi .......................... 38; pi. 4

Clipperton Island _______--9,11,12,16,36

compressa, Bythocypris ________________ 18

Contemporaneous faunas _____________ 9

Contemporaneous forms .-----------_- 36

convoluta, Cytherc .................... 21

Radimella .......... 3, 9, 10, 21; pis. 2, 11

Coquimbinae -.....-......-___________ 23

Correlation -----------------------__ 9

Costa barri ___________________________ 28

crenata, Callistocythere .......... 8, 31; p]. 14

Cythcre .......................... 31

crispata, Callistocythere ..-..--.-...... 31

Cythcre ....._____________ 31

croneisi, Aglaiocypris ................. 20

crosskeiana, Bairdia __________________ 11

crumena, Bairdia ...................... 15

Glyptobairdia ......______________ 15

Triebelina ................... 7, 15; pi. 1

Cuba -----__--_____.-____ 10,19,36

Page

cubcnsis, Triebelina .................__ F15

cuneata, Hemicytherura _-______------_ 30

cuneolus, Cythere _____.___-_____----_- 34

Havanardia -------------- -- 14; pi. 1, 8

Current circulation patterns ____- --- 11

curta, Xestoleberis ........ 3, 9, 35; pis. 15, 17

Cypridacea ______________-___-__------ 19

Cyprideis ............ .-...-.. . 19,29

beaconensis ..... __ 3, 9, 10, 29; pis. 6, 13

lengae ______________--__---_____-_ 29

(Goerlichia) miguelensis .....- -- 29

(Goerlichia) stewarti ------------- 29

(Goerlichia) sp ---------------- 29

Cyprididae ....___________--_-__------- 19

Cypridina deformis __._____.______-- 21

Cypridopsinae ........................ 19

Cytheracea ________-__---_----- ----- 20

Cythere caudata ............. 36; pi. 16

convoluta ________________________ 21

crenata ___________________________ 31

crispata ____________ ____________ 31

cuneolus _______-__________--_-_-_- 34

inconspicua ___-_____________------ 34

lactea ......-.--.------.-----.---- 25

pannosa .......... -------------- 25

prava ...........----.---......... 26

rastromarginata __----__--_------- 28

Cythereis bicarinata ___________________ 25

sebastianensis --------------------- 28

tschoppi .------..---..------.-.. 27

vicksburgensis -------------------- 25

Cythcrella ______ - 36 

foveata ____-_______---____-- ___- 36

textum ..................... 1, 36; pi. 17

vanveeni .......................... 36

sp. a _-_-__---__---_--- ------- 36

sp. 1 _________________- 36; pi. 16

sp. 2 -_____________ 8, 36, 37; pi. 16

Cytherellidae ...........-...._______ 36

Cytherelloidea ------------------------- 8, 37

japonica ... ___-----.___ 11,38; pis. 6, 16

keiji ......-------................. 37,38

praecipua ...____----_-_--------- 37,38

semipunctata ............... 37; pis. 6, 16

umbonata .. ________- 7, 9, 37; pis. 6, 16

sp. 1 _________________- 38; pi. 6

sp. 2 _______---__ 37, 38; pis. 6, 16 

Cytheridea beaconensis ---------------- 29

Cytherideidae _________________________ 29

Cytherideinae _________________________ 29

Cytheromatinac _______________________ 34

Cytheruridae __________ --______------ 30

Cytherurinae .......................... 30

D

datelinensis, Xestoleberis .. _____ 7, 55; pi. 17

deformis, Aurila ...................... 21

Cypridina _________________________ 21

Pokornyella .......... 7, 10, 2i; pis. 1, 11

Procythereis ...----.-.--.......... 21

deltoides, Jugosocythereis ______________ 25

dcmissa, Leptocythere .......... _______ 34

Depth of water in which fauna lived -- 3 

diffusia, Loxoconcha antillea _-__ 52; pis. 4, 14 

dimorpha, Macrocypris ......... 10, iS; pi. 10

Dimorphism ____ 13, 14, 17, 19, 20, 30, 31, 35,36

F41
F42 INDEX

Page

East coast, United States _______ F23 

East Indies _____--________ 11,20

Easter Island --- _-_-_-__________ 19

Ecological or environmental

preferences _ 3, 4,19, 31, 37 

edwardsii, Rectotrachyleberia __________ 29

El Salvador __________________ 11,12

elongata, Bythocypris _________________ 18

Environments, brackish water _______ 9

climatic changes ----------____-___ 8

lagoonal ._--_______-_____________ 19

littoral zone ______________________ 17

open lagoon ______________________ 30

restricted __-_--_-_______________ 9

tropical __-.___________________ 8

Eocene ____________________________ 10

eopacifica, Parakrithella ________ 7, 31; pi. 17

Europe .___________________________ 29

Euryhaline tolerance __-----_-_________ 19

F

Fanning Island _________________ 35

Fiji ____________ 11,19,25,31,34,36

fischeri, Loxoconcha __________________ 32

flabellacosta, Orionina ________ 8, 20; pis. 3, 11

Florida ____________________ 34

foveata, Cytherella -__--___-___________ 36

franquesi, Paracypris _______ 7, 10, 19; pi. 10

Funafuti ____________________ 11,25 

drill holes ________________ 10

fungosa, Hermanites __________________ 27

G

Galapagos Islands ___________________ 20

Geographic affinities ________________ 4, 7

gierloffi, Neonesidea ____________ 3, 11; pi. 7

Triebelina _______________________ 11

Glyptobairdia crumena _______________ 15

(Goerlichia) miguelensis, Cyprideis ____ 29

stewarti, Cyprideis ________________ 29

sp., Cyprideis -_--_-______________ 29

gordoni, Hemicythere _______ 7, 8, 10, SO; pi. 2

gracilis, Macrocyprina _____________ 19; pi. 10

Pontocypris ____________---_______ 19

granulosa, Xestoleberis ____-._ 3, 34; pi. 15 

Great Barrier Reef ___________ 34

Growth stages ______________________ 16

Guatemala ____________________ 36

Gulf coast ________________ 10,25,28 

Gulf of Mexico _______________ 11, 16

H

haidingeri, Hermanites ________________ 27

Hammatocythere _____________________ 28

sebaatianensis ______ 7, 8, 10, 28; pi. 3, 12

Hanauma Bay, Hawaii ________________ 8

hanaumaensis, Bairdia _--__-_________ 15

Friebelina ______________________ 8, 15, 16

handeli, Paranesidea ___________ 8, 16; pi. 8

Havanardia _________________________ 14

cuneolus _____________________ 14; pi. 1, 8

sp. 1 __ _ 8,U; Pi. 8 

sp. 2 _ _______ 8, 15; pi. 8

sp. 3 __.________________ 15; pi. 8

Hawaiian Islands _____ 11, 19, 22, 25, 27, 29,

33, 34, 36 

Hawaiian Ridge _---------__-_________ 1

hawaiianensis, Hermanites _________ 27; pi. 5

Hemicythere __________________________ 20

gordoni ____----_______ 7, 8, 10, 20; pi. 2

Hemicytheridae ____--_-_----_________ 20

Hemicytherinae ---------------------_ 20

Page

Hemicytherura ---------- ------------ F30

cuneata -------------------- ----- 30

pentagona _______---- 4, 9, 30; pi. 13

Hermania reticulata __ _________----__ 27

Hermanites --------------------------- 27

barri ______-_________ 28; pis. 4, 12

fungosa _________________________ 27

haidingeri ------------------------ 27

hawaiianensis _________________ 27; pi. 5

hornibrooki _____________--_-_---_ 27

paijenborchiana ____--__---------__ 27, 28

pannosa -------------------------- 25

praehawaiianensis ------------ 7, 27; pi. 5

tosaensis ________________________ 27

tschoppi .. 5, 7, 8, 9, 10, 27, 28; pis. 4, 12, 13 

sp - __-- __ 27

Hong Kong _____________---__-----__- 31

honoluliensis, Loxoconcha -------------- 33

Honshu, Japan ____________________ 10, 33

hornibrooki, Hermanites --------------- 27

inconspicua, Cythere ____ ____________ 34

Munseyella ______-__-_-_ 11, 34; pis. 1, 11

India _______--_______--_--- 11 

Indian Ocean ________________ ------- 20

Indonesia _____________________ ----- 15

Indopacific Realm ______-______---_--- 11

inflata, Pokornyella

pseudojaponica _______ 21; pi. 11

Interruption in sequences ------------- 3

Japan __________________ 11,21,30,31 

japonica, Ambocythere -__________----_ 38

Cytherelloidea ___-._ _ 11, 38; pis. 6, 16 

Pokornyella --------------------------- 21

Jugosocythereis _____________________ 23, 24

bicarinata ------------------------ 25

canalicttlata ______________________ 3, 8

canaliculata _________ 24; pis. 4, 12, 14

reticulata _--_____ 9, 10, 25; pis. 4, 12

deltoides -------------------------- 25

lactea _____-.-__-__---- 25; pis. 3, 12

pannosa ______________ 7, 10, 25; pis. 3, 12

venulosus ------------------------- 25

vicksburgensis -------------------- 25

K

Kanmu Seamount --------------------- 1

kauaiensis, Bairdia -------------------- 12

Neonesidea ___________ 3, 9, 12; text-fig. 4

Kerguelen ______________------------- 16

Kure atoll lagoon ______--_------------ 17

Krithidae ----------------------------- 30

Krithinae ----------------------------- 30

Kuroshio Current ____________ -_____- 11

lactea, Cythere ------------------------ 25

Jugosocythereis ------------- 25; pis. 3, 12

laevicula, Aurila ---------------------- 23

lengae, Cyprideis -------------- _-___-_ 29

Leptocythere demissa ----------------- 34

Leptocytheridae _-__-_________________ 31

Levant (eastern Mediterranean) __--__ 11 

Limburg ____________________________ 36

lincolnensis, Aurila ______--__ 22; pis. 2, 11, 16

Line Group __ ____-_-__-________--__- 35

Line Islands __________________________ 25

Lineages __-___ 13,22,24,27,31,33,35,37

longispina, Loxoconcha __ 3, 9, 32; pis. 4, 5, 14

Loxoconcha alata ----------------- 32

Louisiana __---___-_-__-_______-----_- 19

Page

Loxoconcha ----------------------- F8, 24, 32

alata ----------------------------- 32

longispina ----------------- - 32

antUlea . _____ 8, 9, 10, 32, 33; pis. 4, 5, 14 

diffusia -- ------- 32; pis. 4, 14

fischeri --------------------------- 32

longispina ._-- 3, 9, 32; pis. 4, 5, 14 

uranouchiensis --- 3, 9, 10, 11, 32; pis. 4, 14 

sp. 1 ___________ -_ 33; pi. 14 

sp. 2 __-__-__------ 32, 33; pi. 5

Loxoconchella ------------------------- 33

anomala ------------- -------- 33; pi. 6

honoluliensis ----------------- 5, 33; pi. 6

sp __ ________ __ S3; pi. 15

Loxoconchidae ------------------------ 32

M

Macrocyprididae ____ ___.____-_--____ 18

Macrocypridinae ---------------------- 18

Macrocyprina ____________-___-_--- 19

gracilis ________ _______ 19; pi. 10

Macrocypris ____ ____________________ 18

dimorpha ____- - 10, 18; pi. 10 

Madagascar __-_____----___- ________ 15, 17

madagascarensis, Amphistegina -------- 9

magnumcaudata, Bairdoppilata

planolata ------------ 8, 18; pi. 9

Major assemblages __ _------__-__ 3

Manila Bay -__--__-_----------------__ 36

Mexico, west coast ___________ ------ 12

miguelensis, Cyprideis (Goerlichia) __-_ 29 

Muellerina ---------------------------- 23

sp _____-.__---______-- 8, 23; pi. 5 

Munseyella --------------------------- 34

inconspicua ------------- 11, 34; pis. 1, 11

Mutilus oahuensis -------------------- 22

N

Neocaudites -------------------------- 28

terryi - ________ ------- 29

sp ---______________-__ 8, 28; pi. 12 

Neonesidea cassida __ ____ 7, 8, 10, 11; pi. 7

gierloffi _____________ _. 3, 11; pi. 7

kauaiensis ____________ 3, 9, 12; text-fig. 4

reefholensis -------------------- 13; pi. 8

ritugerda ------------------------- 12

schulzi -------------- --------- 12; pi. 7

simuvillosa ------------------ 12, 13; pi. 7

spica __._-- ----------_--_-_ 8, 12; pi. 7

verdesensis ----------------------- 12

sp. 1 -____ 14; pi. 7 

sp. 2 __-___----- _ 14; pi. 7

sp. 3 -- U;v\. 7 

Nephokirkos __-____-__ -_--_________- 23

New Caledonia _______ 11,15,25,26,31,36 

New Hebrides _______----- ----- 31,34

New Zealand ________----------- 11, 30

Nonpreservation versus temporary

local extinction __---_____ 15

North Atlantic Equatorial current __ 11 

North Pacific Equatorial current ______ 11

northpacifica,

Procythereis __ 4, 8, 9, 23, 27; pi. 2 

Nosy Be, Madagascar ___-_____-___-_-- 12

O

Oahu, Hawaii ___-___._________ 30 

oahuensis, Mutilus -------------------- 22

Occultocythereis ---------------------- 29

sp -_-_----__-__--------------- 29; pi. 12

Okinawa _______ _ _ 11,31

Orionina ----------------------------- 20

flabellacosta ---------- __-_ 8, 20; pis. 3, 11

Ostracode sp ---------------------- 36; pi. 16
INDEX F43

Page

Pacific Realm __________________ 11

paijenborchiana, Hermanites __________ 27, 28

Paleoclimatic indications --_-----_-____ 8

Panama ___ -------___--_-__. 35

pannosa, Cythcre _____.__-_-_________ 25

Hermanites _____________________ 25

Jugosocythereis _______ 7, 10, 25; pis. 3, 12

Paracypridinae _ ______________ 19

Paracypris ------------------________ 19

franquesi -._________ 7, 10, 19; pi. 10

roeefieldensie -_______ 7, 10, 19; pi. 10 

Paracytheridea ______________________ 30

tschoppi _._ ________________ 30

sp _ 8, SO; pi. 13 

Paracytherideidae _________________ 30

Paracytherideinae ..___________ 30

Paradoxostoma _--_________________ 33

romei ___ .-_.___________ 33; pi. 15 

sp. 1 _____ 34; pi. 15

sp. 2 _____ 8,34; pi. 15

Paradoxostomatidae . __-_-__-________ 33

Paradoxostomatinae ________________ 33

Parakrithella ...__________________ 11, 30

eopacifica _.____________ 8, 31; pi. 17

pseudadonta ______________________ 31

robusta ________ 4, 8, 9,30, 31; pis. 6, 13

Paranesidea .-_-._._________ 14, 16

algocola __ _____________ 17

handeli ____ _______ 8, 16; pi. 8

victrix .. ____________ 16; pi. 9

sp. 1 __ 17; pi. 9

sp. 2 ____ 8, 17; pi. 9

Patagonacythere ______________________ 8

sebastianensis _____________ 33

Pectocytheridae .............._______ 34

Pettucistoma __________--_-_________ 34

sp _ 34; pi. 15 

pentagona, Hemicytherura .... 4, 9, 30; pi. 13

Phenotypic variants __________ 17,24,38

Philippines ______________ 34 

planolata, Bairdoppilata planolata __ 17; pi. 9 

maffnumcaudata,

Bairdoppilata ______ 8, 18; pi. 9

pZonoZota, Bairdoppilata ________ 17; pi. 9

ventrocaudata, Bairdoppilata ___ IS; pi. 9 

Platycopina ___________________ 36

Platycosta _____ ___---___._____ '29

amicus ......... ._____ S9; pis. 4, 13

Pleistocene sediments, faunal evidence

for _ 10 

Pokornyella .........____________ 2l

calix .....................____ 21

deformis .................. 7, 10, SI; pis. 1, 11

japonica ........______________ 21

pseudojaponica ___________ 8, 9,11

inflata ......____________ SI; pi. 11

pseudojaponica ......... 21; pis. 2, 11

polycosta, Radimella .................. 5,8

Radimetta polycosta ...... 22; pis. 1, 2, 11

polycosta, Radimetta ..... SS; pis. 1, 2, 11

rugosa, Radimella ....... 8, S3; pis. 2,11

Pontocyprella .-....................... 20

sp. 1 SO; pi. 10

sp. 2 .__________________ SO; pi. 10

Pontocypris yracilis .---____________ 19

Port Jackson, Australia ______________ 31, 35

Port Phillip Bay, Victoria, Australia __ 35 

Potamocypris ...................._____ 19

sp _______________-_____ 19; pi. 10 

praecipua, Cytherelloidea _____________ 37

prava, Cythere _ _ _-___-_____-_ 26

Prisbram's law _ 16

Procythereis -___ 23

deformis .......................... 21

northpacifica ____ 4, 8, 9, 23, 27; pi. 2 

pseudadonta, Parakrithella ......______ 31

Page

pseudojaponica, Pokornyella ________ F8, 9, 11

Pokornyella pseudojaponica . 21; pis. 2, 11 

inflata, Pokornyella ___________ 21; pi. 11

pseudojaponica, Pokornyella _ 21; pis. 2, 11

Puerto Rico ______ __ 10, 18, 19, 20, 21, 36

Q

Qatar ____________ _ ___ 34

Quadracythere ...._________________ 23

aequabilis ___ __ .----__ S4; pi. 17

spica ..............._________ S4; pi. 5

trijugis ------------- 8, 23, 24; pis. 3, 5, 12

quadranodosa, Tenedocythere ___ 26; pis. 5, 12

R

Radimetta ____-----------_----------_- 21

convoluta . _________ 3, 9, 10, 21; pis. 2, 11

polycosta ..........--_____________ 5, 8

polycosta ............ 22\ pis. 1, 2, 11

rugosa __________ 8, 22; pis. 2, 11

resigi __________________ _________ 22

rastromarginata, Cythere ......__--___ 28

Rectotrachyleberis edwardsii ______--. _ 29

Reef hole __ -- 1,11

fauna ._ - 7 

reefholensis, Neonesidea ____________ 13; pi. 8

References cited 38 

reniformis, Bythocypris ____ 4, 5, 8, 18; pi. 1

resigi, Radimella ___-_______---__-----_ 22

reticulata, Hermania .................. 27

Jugosocyth ereis

canaliculata .. 9, 10, 25; pis. 4, 12 

reticulopuncta, Triebelina ............. 7, 8

Reworked specimens _______ _______ 19, 25

ritugerda, Bairdia ............... ______ 12

Neonesidea _______________________ 12

robttsto, Parakrithella . 4, 8, 9, 30, 31; pis. 6. 13 

Rock types -___ -- 1 

romei, Paradoxostoma ------------ 33; pi. 15

rosefieldensis, Paracypris __ 7, 10, 19; pi. 10 

ruyosa, Radimella polycosta ._ 8, 22; pis. 2, 11

Triebelina ___-_-____-_-__---_--___ 16

Samoa ------ ____-____-__-_-_-___--_ 11, 15

San Diego Formation ______ ____ 12

San Pedro Formation _______-__----. 12

Sand Island hole _________.----_ 1, 11

faunas ____---_--__-__--__--- __ 9 

Santa Barbara Formation _-_.__-.____ 12 

schulzi, Neonesidea ______________ 12; pi. 7

Triebelina _________________ 12 

Seaway connections _________ ___ __ 11

sebastianensis, Cythereis ............... 28

Hammatocythere ____ 7, 8, 10, S8; pis. 3,12

Patagonacythere . ____ ________ 38

Semicytherura _______________________ 8, 30

sp ______ ________---_ 30; pi. 13 

semipunctata, Cytherelloidea ... 37; pis. 6, 16 

setigera, Tenedocythere .. 8, 26; pis. 2, 3, 5, 12 

simuvillosa, Neonesidea ._______ IS, 13; pi. 7

spica, Neonesidea ________________ 8, 12; pi. 7

Quadracythere ........---------- 24; pi. 5

steu'arti, Cyprideis (Goerlichia) _______ 29

Stratigraphic distribution patterns ____ 3

faunal gaps ____-_____________ 9

Switzerland ____________________ 21 

Sydney, Australia ___ --_--------_-__ 16

Systematic paleontology ___ __ _ 11

Tenedocythere __ _-_-_._----_-_----- 25

quadranodosa _____ 26; pis. 5, 12

setigera .............. 8, 26; pis. 2, 3, 5,12

turda ------------------ 25, 26; pis. 1, 12

Page

terryi, Neocaudites -------------------- F29

textum, Cytherella 1,36; pi. 17 

Thaerocytherinae _________._--__-- 23

Tonga __________________ 10,19,23,30 

Tongabatu, South Pacific --- 18 

Torres Strait ____ 31,34 

tosaensis, Hermanites ................. 27

Trachyleberididae _______.-__-. __ 28

Trachyleberidinae . __ ----- 28

Triebelina ---------------------------- 15

bradyi ...--...---------.......- . 9,15

crumena _________________ - 7, 15; pi. 1

cubensis .......................... 15

gierloffi ........... -. --....-- 11

Triebelina hanaumaensis ........... 8,15,16

reticulopuncta 7, 8, 15; pi. 8 

rugosa ..-....................-. _ 16

schulzi -------------...--.-....... 12

sp. 1 ___________________ IS; pi. 8

sp. 2 _______ 16; pi. 8

trijugis, Quadracythere 8, S3, 24; pis. 3, 5, 12

Timms Point Silt Member _________ 12

Trinidad __ 21 

Tristan de Cunha ______-_ -._.- 16 

truncata, Bairdia ....-___.____-_-_-_. 15

tschoppi, Hermanites _______ 5, 7, 8, 9, 10, 27,

28; pis. 4, 12,13 

Cythereis __ ______ __-. 27

Paracytheridea -------------------- 30

tiimefacta, Xestoleberis __________ 9, 34; pi. 16

turda, Tenedocythere ........ 25, 26; pis. 1, 12

umbonata, Cytherelloidea .. 7, 9, 37; pis. 6, 16 

Unconformity _- ----------- _ 8

uranouchiensis,

Loxoconcha .-_.. 3, 9, 10, 11, 32;

pis. 4,14

vanveeni, Cytherella _----_--__--.-_---_ 36

Variants _. .-- - 17,21,27,32,37 

Venezuela ______--__---___----------_- 21

ventrocaudata, Bairdoppilata

planolata .... -_.__ ____ 18

venulosus, Jugosocythereis .- ------- 25

verdesensis, Neonesidea ____-____ 12

Vicksburg _ 19

vicksburgensis, Cythereis ... _ __ 25

Jugosocythereis ___ _____ 25

victrix, Bairdia --------------------- 16

Paranesidea ____ ________--_-__ 16; pi. 9

W

West coast, North America 20

Xestoleberidae -....................... 34

Xestoleberis ....----------------------- 8, 34

briggsi ......... .......... 8, 35; pi. 16

curia, ............. 3, 9, 35; pis. 15, 17

datelinensis - -- --- 7, 35; pi. 17 

granulosa ------------------- 3, 34; pi. 15

tumefacta ........ . 9, 34; pi. 16

sp. B ____ 35 

sp. 1 ________________ 5, 9, 35; pi. 15 

sp. 2 __________ Sfi; pi. 15

PLATES 1-17

Contact photographs of the plates in this report are available, at cost, from 

U.S. Geological Survey Library, Federal Center, Denver, Colorado 80225
PLATE 1

FIGURES 1,2.

4.

5,6.

7,12,13, 

17,18.

10.

11.

14-16.

Bairdoppilata sp. aff. B. bradyi (Bold) (p. F17).

1. Lateral view adult male left valve. KR-12.19 m. Specimen USNM 184356. 

(See pi. 9, fig. 21 for internal view.)

2. Lateral view adult female left valve. S-44.20 m. Specimen USNM 184355 

Havanardial cuneolus Holden, n. sp. (p. F14).

Right valve lateral view adult carapace. R-342.90 m. Holotype USNM 184321 

Pokornyella deformis (Reuss) ? (p. F21).

Right valve lateral view adult carapace. R-317.60 m. Hypotype USNM 184397 

Triebelina crumena (Stephenson) (p. F15).

5. Left valve lateral view adult carapace. R-326.55 m. Hopotype USNM 

X 56.

6. Left valve lateral view adult carapace. R-321.87 m. Hypotype USNM 

X 48.

Bythocypris reniformis Brady (p. F18).

7. Lateral view young right valve. S-147.83 m. Hypotype USNM 184373. X

12. Left valve lateral view adult carapace. R-172.21 m. Hypotype USNM 

X 51.

13. Left valve lateral view adult carapace. R-321.86 m. Hypotype USNM 

X 51.

17. Right valve lateral view adult carapace. R-317.60 m. Hypotype USNM 

X 50.

18. Lateral view adult right valve. S-147.83 m. Hypotype USNM 184372. X 50. 

Radimella polycosta Holden, n. sp. sensu stricto (p. F22).

8. Left valve lateral view adult carapace. R-308.76 m. Paratype USNM 

X 52.

9. Left valve lateral view adult carapace. R-308.46 m. Paratype USNM

X 53. 

Caudites sp. (p. F20).

Lateral view adult right valve. S-140.21 m. Specimen USNM 184389. X 52. 

Tenedocythere turda Holden, n. sp. (p. F25).

Lateral view young right valve. R-338.94 m. Paratype USNM 184455. X 53. 

Munseyella, inconspiciia (Brady) (p. F34).

From R-313.64 m.

14. Right valve lateral view adult carapace. Hypotype USNM 184570. X 52.

15. Left valve lateral view adult carapace. Hypotype USNM 184571. X 54.

16. Dorsal view adult carapace. Hypotype USNM 184572. X 52.

X 52.

X 49. 

. X 52. 

. X 55. 

184328. 

184327.

50.

184376.

184374.

184375.

184415.

184414.
PROFESSIONAL PAPER 680-F PLATE 1

BAIRDOPPILATA, HAVANARDIA*!, POKORNYELLA, TRIEBELINA, BYTHOCYPRIS, RADIMELLA, CAUDITES,

TENEDOCYTHERE, AND MUNSEYELLA
PLATE 2

FIGURE 1. Radimella convoluta (Brady) (p. F21).

Left valve lateral view adult carapace. S-73.46 m. Holotype USNM 184411 X 53. 

2. Radimella polycosta Holden, n. sp. sensu stritco (p. F22).

Lateral view adult left valve. S-140.21 m. Holotype USNM 184416. X 52. 

3,4. "Hemicythere" gordoni Bold (p. F20). 

From R-308.46 m.

3. Left valve lateral view adult carapace. Hypotype USNM 184424. X 48.

4. Lateral view adult left valve. Hypotype USNM 184425. X 50. 

5. Tenedocythere setigera Holden, n. sp. (p. F26).

Left valve lateral view adult carapace. R-311.35 m. Paratype USNM 184467. X 52. 

6,7. Radimella polycosta rugosa Holden, n. sp., n. subsp. (p. F22). 

From R-173.28 m.

6. Lateral view adult right valve. Paratype USNM 184419. X 51.

7. Lateral view adult left valve. Holotype USNM 184418. X 51. 

8. Aurila sp. aff. A. lincolnensis (LeRoy) (p. F22).

Lateral view adult left valve. R-321.87 to 323.39 m. Specimen USNM 184421. X 52. 

9-18. Pokornyella pseudojaponica Holden, n. sp. sensu stricto (p. F21).

9. Lateral view adult right valve. S-147.37 m. Paratype USNM 184402. X 53.

10. Lateral view adult right valve. S-147.37 m. Paratype USNM 184403. X 52.

11. Lateral view adult left valve. S-140.21 m. Paratype USNM 184404. X 52.

12. Right valve lateral view adult carapace. R-172.21 m. Paratype USNM 184400. 

X 52.

13. Lateral view adult left valve. S-149.66 m. Paratype USNM 184405. X 51.

14. Lateral view adult right valve. S-140.21 m. Paratype USNM 184407. X 51.

15. Lateral view adult right valve. S-l71.91 m. Paratype USNM 184401. X 51.

16. Left valve lateral view adult carapace. R-172.21 m. Paratype USNM 184399. 

X 52.

17. Left valve lateral view adult carapace. R-160.63 m. Paratype USNM 184406. 

X 52.

18. Left valve lateral view adult carapace. R-161.24 m. Paratype USNM 184408.

X 52. 

19-21. "Procythereis" northpacifica Holden, n. sp. (p. F23).

19. Lateral view adult right valve. R-147.37 m. Paratype USNM 3 84430. X 52.

20. Lateral view adult left valve. R-152.40 m. Holotype USNM 184431. X 53.

21. Left valve lateral view adult carapace. R-147.37. Paratype USNM 184429. X 47.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 2

RADIMELLA, "HEMICYTHERE," TENEDOCYTHERE, AURILA, POKORNYELLA, AND "PROCYTHEREIS "
PLATE 3

FIGURES 1-4,16. Hammatocytherel sebastianensis (Bold) (p. F28).

1. Lateral view adult right valve. R-296.66 m. Hypotype USNM 184503. X 52.

2. Lateral view adult left valve. R-318.67 m. Hypotype USNM 184504. X 53. (See 

pi. 12, figs. 1, 4, for dorsal and internal views.)

3. Lateral view adult right valve. R-318.67 m. Hypotype USNM 184505. X 52. 

(See pi. 12, fig. 2, for dorsal view.)

4. Dorsal view adult carapace. R-318.67 m. Hypotype USNM 184506. X 52.

16. Left valve adult carapace. R-296.66 m. Hypotype USNM 184507. X 52. 

5-7. Orionina flabellacosta Holden, n. sp. (p. F20).

5. Lateral view adult female left valve. R-343.30 m. Paratype USNM 184391. X 52.

6. Lateral view adult female left valve. R-355.09 m. Paratype USNM 184392. X 50.

7. Right valve lateral view adult male carapace. R-344.12 m. Holotype USNM

184390. X 50. 

8-13. Tenedocythere setigera Holden, n. sp. (p. F26).

8. Lateral view adult left valve. R-343.30 m. Paratype USNM 184463. X 51.

9. Dorsal view adult carapace. R-343.30 m. Paratype USNM 184464. X 50.

10. Lateral view adult left valve. R-338.94 m. Holotype USNM 184465. X 51. (See 

pi. 12, fig. 13, for internal view.)

11. Lateral view adult (?) right valve. R-308.46 m. Paratype USNM 184466. X 52.

12. Left valve view adult carapace. R-320.65 m. Paratype USNM 184469. X 52.

13. Right valve view adult carapace. R-320.65 m. Paratype USNM 184470. X 51. 

14,15. Quadracythere trijugis Holden, n. sp. (p. F23).

14. Left valve view adult carapace (large form). S-140.21 m. Holotype USNM 184432. 

X 51.

15. Right valve view adult carapace (small form). R-326.14 m. Paratype USNM

184433. X 51. 

17-21. Jugosocythereis pannosa (Brady) (p. F25).

17. Left valve view adult carapace. S-149.05 m. Hypotype USNM 184475. X 52.

18. Left valve view adult carapace. R-355.09 m. Hypotype USNM 184472. X 51.

19. Dorsal view adult carapace. R-355.09 m. Hypotype USNM 184473. X 50.

20. Right valve view adult carapace. R-355.09 m. Hypotype USNM 184471. X 51.

21. Left valve view adult carapace. R-343.30 m. Hypotype USNM 184474. X 52. 

22,23. Jugosocythereis lactea (Brady) (p. F25).

22. Lateral view adult right valve. S-73.46 m. Hypotype USNM 184451. X 53.

23. Left valve view adult carapace. S-74.22 m. Hypotype USNM 184452. X 50.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 3

HAMMATOCYTHEREl, ORIONINA, TENEDOCYTHERE, QUADRACYTHERE, AND JUGOSOCYTHEREIS.
PLATE 4

FIGURES 1-5. Jugosocythereis canaliculata reticulata Holden, n. sp., n. subsp. (p. F25).

1. Lateral view adult left valve. S-86.87 m. Holotype USNM 184445. X 52.

2. Lateral view adult right valve. S-86.87 m. Paratype USNM 184446. X 50.

3. Lateral view adult left valve. S-91.14 m. Paratype USNM 184450. X 51.

4. Right valve lateral view adult carapace. S-90.37 m. Paratype USNM 184449. 

X 51.

5. Left valve lateral view adult carapace. S-90.37 m. Paratype USNM 184448.

X 52. 

6-9,15. Hermanites tschoppi (Bold) (p. F27),

6. Lateral view adult female left valve. R-344.27 m. Hypotype USNM 184488. 

X 52.

7. Left valve lateral view adult female carapace. S-141.37 m. Hypotype USNM 

184487. X 51. (See pi. 13, fig. 3, for dorsal view.)

8. Lateral view adult male left valve. S-141.73 m. Hypotype USNM 184486. X 51. 

(See pi. 13, fig. 4, for internal view.)

9. Lateral view adult male right valve. R-296.66 m. Hypotype USNM 184489. X 55. 

15. Lateral view adult female left valve. R-296.66 m. Hypotype USNM 184490 X 54. 

10,11. Loxoconcha antillea Bold sensu stricto (p. F32).

10. Lateral view adult female left valve. S-140.21 m. Hypotype USNM 184542. X 50. 

(See pi. 14, fig. 6, for internal view.)

11. Lateral view adult male left valve. S-141.73 m. Hypotype USNM 184543. X 51.

12. Loxoconcha uranouchiensis Ishizaki (p. F32).

Lateral view adult female left valve. S-45.11 m. Hypotype USNM 184551. X 51.

13. Cletocythereis bradyi Holden (p. F28).

Left valve lateral view adult female carapace. S-44.20. Hypotype USNM 184492. 

X 52.

14. Loxoconcha longispina Key (p. F32).

Lateral view adult male left valve. S-147.37 m. Hypotype USNM 184537. X 55. 

16,17. Platycosta amicus Holden, n. sp. (p. F29). 

From R-336.27 m.

16. Right valve lateral view adult male carapace. Paratype USNM 184497. X 52.

17. Left valve lateral view adult female carapace. Holotype USNM 184498. X 52. 

18-21. Loxoconcha antillea Bold diffusa Holden, n. subsp. (p. F32).

18. Left valve lateral view adult female carapace. R-318.52 m. Holotype USNM 

184546. X 51.

19. Left valve lateral view adult male carapace. R-343.30 m. Paratype USNM 184547. 

X 51.

20. Right valve lateral view adult female carapace. R-343.30 m. Paratype USNM 

184548. X 52.

21. Dorsal view adult male carapace. R-343.30 m. Paratype USNM 184549. X 50. 

22,23. Jugosocythereis canaliculata Holden, n. sp., sensu stricto (p. F24). 

From S-45.11 m.

22. Lateral view adult left valve. Holotype USNM 184442. X 51. (See pi. 14, fig. 

16, for internal view.)

23. Right valve lateral view adult carapace. Paratype USNM 184443. X 51. 

24. Hermanites sp. aff. H. barri (Bold, 1960) (p. F28).

Lateral view adult right valve. S-148.74 m. Specimen USNM 184493. X 49. (See 

pi. 12, fig. 21, for dorsal view.)
PROFESSIONAL PAPER 680-F PLATE 4

JUGOSOCYTHEREIS, HERMANITES, LOXOCONCHA, CLETOCYTHEREIS,AND PLATYCOSTA
PLATE 5

FIGURES 1,2. Loxoconcha antillea Bold sensu stricto (p. F32).

1. Lateral view adult male left valve. R-161.39 m. Hypotype USNM 184539. X 51.

2. Lateral view adult female left valve. S-141.73 m. Hypotype USNM 184540.

X 51. 

3-6. Loxoconcha longispina Key (p. F32).

3. Lateral view adult male left valve. S-78.88 m. Hypotype USNM 184532. X 51. 

(See pi. 14, fig. 13, for internal view.)

4. Lateral view adult male right valve. S-78.88 m. Hypotype USNM 184533. X 51.

5. Lateral view adult female right valve. S-79.19 m. Hypotype USNM 184535. X 52.

6. Lateral view young left valve. S-78.88 m. Hypotype USNM 184534. X 50. 

7-9. Loxoconcha sp. 2 (p. F33). 

From R-355.09 m.

7. Left valve lateral view adult carapace. Specimen USNM 184558. X 51.

8. Dorsal view adult carapace Specimen USNM 184559. X 51.

9. Right valve lateral view adult carapace. Specimen USNM 184557. X 52. 

10-12,14-16. Hermanites praehawaiianensis Holden, n. sp. (p. F27).

10. Right valve lateral view adult carapace. R-321.87 m. Holotype USNM 184483. 

X 53.

11. Right valve lateral view adult carapace. R-343.30 m. Paratype USNM 184480. 

X 51.

12. Right valve lateral view adult carapace. R-311.35 m. Paratype USNM 184485. 

X 51.

14. Left valve lateral view adult carapace. R-343.30 m. Paratype USNM 184481. 

X 52.

15. Left valve lateral view adult carapace. R-336.27 m. Paratype USNM 184484. 

X 52.

16. Dorsal view adult carapace. R-343.30 m. Paratype USNM 184482. X 53. 

13. Hermanites hawaiianensis Holden, n. sp. (p. F27).

Lateral view adult left valve. S-91.14 m. Holotype USNM 184479. X 53. 

17,18. Muellerinal sp. (p. F23).

17. Left valve lateral view adult carapace. R-311.81 m. Specimen USNM 184428. 

X 51.

18. Left valve lateral view adult carapace. R-311.35 m. Specimen USNM 184427.

X 51. 

19-21. Tenedocythere quadranodosa Holden, n. sp. (p. F26).

19. Lateral view adult left valve. S-141.73 m. Paratype USNM 184459. X 51. (See 

pi. 12, fig. 11, for dorsal view.)

20. Lateral view adult right valve. S-141.73 m. Holotype USNM 184460. X 50. (See 

pi. 12, fig. 12, for dorsal view.)

21. Lateral view adult left valve. S-140.21 m. Paratype USNM 184461. X 51. 

22,25. Quadracythere spica Holden, n. sp. (p. F24).

22. Left valve lateral view adult carapace. R-343.30 m. Hypotype USNM 184441.

X 53. 

25. Lateral view adult left valve. R-343.05 m. Paratye USNM 184440. X 51.

23. Tenedocythere setigera Holden, n. sp. (p. F26).

Left valve lateral view adult carapace. R-296.66 m. Paratype USNM 184468. X 52.

24. Quadracythere trijugis Holden, n. sp. (p. F23).

Lateral view young right valve. S-140.21 m. Paratype USNM 184435. X 51.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680 -F PLATE 5

LOXOCONCHA, HERMANITES, MUELLERINA1, TENEDOCYTHERE, AND QUADRACYTHERE
PLATE 6

S-149.66 m. Specimen USNM

FIGURES 1,2. Cytherelloidea semipunctata Holden, n. sp. (p. F37). 

From R-308.45 m.

1. Lateral view adult female right valve. Holotype USNM 184617. X 50.

2. Lateral view adult female left valve. Paratype USNM 184618. X 52. 

3,4. Cytherelloidea sp. 2 (p. F38). 

From R-318.52 m.

3. Lateral view adult male right valve. Specimen USNM 184623. X 52.

4. Lateral view adult female right valve. Specimen USNM 184624. X 50. 

5-8,10. Cytherelloidea sp. cf. C. umbonata Edwards (p. F37).

5. Left valve lateral view adult female carapace.

184610. X 51.

6. Left valve lateral view adult female carapace. R-343.30 m. Specimen USNM

184611. X 51.

7. Left valve lateral view adult male carapace. R-343.30 m. Specimen USNM

184612. X 52.

8. Lateral view adult male left valve. R-343.30 m. Specimen USNM 184613. X 52. 

10. Lateral view adult female right valve. S-141.73 m. Specimen USNM 184614. X 51. 

9. Cytherelloidea sp. cf. C. umbonata Edwards variation (p. F37).

Lateral view adult female left valve. R-338.94 m. Specimen USNM 184616. X 50. 

(See pi. 16, fig. 21, for dorsal view.)

11. Cytherelloidea sp. 1 (p. F38).

Lateral view adult male right valve. S-44.20 m. Specimen USNM 184622. X 50.

12. Cytherelloideat japonica Ishizaki (p. F38).

Lateral view adult female right valve. S-44.20 m. Hypotype USNM 184628. X 51. 

(See pi. 16, fig. 20, for dorsal view).

13. Loxoconchella anomala (Brady) (p. F33).

Left valve lateral view adult carapace. MR-21.34 m. Hypotype USNM 184563. X 51. 

14-17. Parakrithella robusta Holden, n. sp. (p. F30).

14. Left valve lateral view adult male carapace. S-140.67 m. Paratype USNM 184521. 

X 52.

15. Lateral view adult female right valve. S-141.73 m. Paratype USNM 184519. X 50. 

(See pi. 13, fig. 16, for dorsal view.)

16. Right valve lateral view adult female carapace. S-140.67 m. Holotype USNM 

184520. X 51.

17. Lateral view adult male left valve. S-141.73 m. Paratype USNM 184518. X 51. 

18-20. Loxoconchella honoluliensis (Brady) (p. F33).

18. Lateral view adult right valve. S-147.37 m. Hypotype USNM 184560. X 50.

19. Right valve lateral view adult carapace. S-149.66 to 151.18 m. Hypotype USNM 

184562. X 51.

20. Lateral view adult right valve. R-173.29 m. Hypotype USNM 184561. X 51. 

21 23. Cyprideis beaconensis (LeRoy) (p. F29).

21. Lateral view adult male right valve. S-74.22 m. Hypotype USNM 184510. X 51. 

(See pi. 13, figs. 5, 7, for internal and dorsal views.)

22. Lateral view adult female right valve. S-78.49 m. Hypotype USNM 184509. X 50. 

(See pi. 13, fig. 6, for dorsal view.)

23. Lateral view adult female left valve. S-78.49 m. Hypotype USNM 184511. X 51.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680 -F PLATE 6

CYTHERELLOIDEA, LOXOCONCHELLA, PARAKRITHELLA, AND CYPRIDEIS
PLATE 7

FIGURE 1. Neonesidea gierloffi (Hartmann) (p. Fll).

Internal view adult right valve. S-44.21 m. Hypotype USNM 184298. 

2-4. Neonesidea sp. aff. N. cassida (Bold) (p. Fll).

2. Right valve lateral view adult carapace. R-320.95 m. Specimen USNM 184299.

3. Dorsal view adult carapace. R-321.72 m. Specimen USNM 184301.

4. Anterior view adult carapace. R-321.72 m. Specimen USNM 184300. 

5-8. Neonesidea sp. cf. N. simuvillosa (Swain) (p. F12). 

From S-147.37 m.

5. Internal view adult female right valve. Specimen USNM 184303. 

6-8. Lateral right valve, dorsal, and anterior views of adult male carapace. Specimen USNM 184302. 

9 11. Neonesidea schulzi (Hartmann) (p. F12).

Right valve lateral, anterior, and dorsal views of adult carapace. R-295.05 m. Hypotype USNM 184305. 

12-14. Neonesidea spica Holden, n. sp. (p. F12).

Dorsal, right valve lateral, and anterior views of adult carapace. R-320.95 m. Holotype USNM 184311. 

15 17. Neonesidea sp. 1 (p. F14).

Anterior, dorsal, and right valve lateral views of adult carapace. R-337.34 m. Specimen USNM 184316. 

18,19. Neonesidea sp. 3 (p. F14).

18. Dorsal view adult right valve. R-321.41 m. Specimen USNM 184319.

19. Internal view adult left valve. R-320.34 m. Specimen USNM 184320. 

20-22. Neonesidea sp. 2 (p. F14).

Dorsal, anterior and right valve lateral views of adult carapace. R-336.56 m. Specimen 

USNM 184318,
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 7

>L

NEONESIDEA
PLATE 8

FIGURES 1-3. Neonesideal reefholensis Holden, n. sp. (p. F13).

Dorsal, anterior, and right valve lateral views of adult carapace. R-343.30 m. Holotype USNM 184314. 

4,5. Havanardia 1! cuneolus Holden, n. sp. (p. F14).

Anterior and dorsal views of adult carapace. R-343.21 m. Paratype USNM 184322. 

6-8. Havanardia sp. 1 (p. F14).

Dorsal, right valve lateral, and anterior views of adult carapace. R-343.30 m. Specimen USNM 184323. 

9. Havanardia sp. 2 (p. F15).

Anterior view adult carapace. R-284.00 m. Specimen USNM 184325. 

10-12. Triebelina reticulopuncta Benson (p. F15).

From R-295.50 m. 

10,11. Right valve lateral and anterior views of adult carapace. Hypotype USNM

184331.

12. Dorsal view adult right valve. Hypotype USNM 184330. 

13. Havanardia sp. 3 (p. F15).

Anterior view adult carapace. R-231.65 m. Specimen USNM 184326. 

14-16. Triebelina sp. 1 (p. F16).

Right valve lateral, dorsal, and anterior views of adult carapace. R-l72.21 m. Specimen USNM 184335. 

17-19. Triebelina sp. 2 (p. F16).

Right valve lateral, dorsal, and anterior views of adult carapace. R-161.24 m. Specimen USNM 184337. 

20-22. Paranesidea handeli Holden, n. sp. (p. F16).

20. Anterior view adult carapace. R-342.90 m. Paratype USNM 184345.

21. Right valve lateral view adult carapace. R-337.72 m. Paratype USNM 184347.

22. Dorsal view adult carapace. R-343.30 m. Holotype USNM 184344.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 8

NEONESIDEAl, HAVANARDIAl, HAVANARDIA, TRIEBELINA, AND PARANESIDEA
PLATE 9

FIGURES 1-4, 6. Paranesidea sp. 2 (p. F17).

1. 3. Right valve lateral and anterior views of adult female carapace. R-311.35 m. 

Specimen USNM 184352.

2. Dorsal view adult left valve. R-311.35 m. Specimen USNM 184353. 

4. Right valve lateral view adult male carapace. R-313.64 m. Specimen USNM 

184354.

6. Right valve lateral view adult carapace, color pattern in stipple. R-285.90 m.

Specimen USNM 184350. 

5. Paranesidea sp. 1 (p. F17).

Right valve lateral view adult carapace. R-341.38 m. Specimen USNM 184349. 

7-9. Paranesidea victrix (Brady) (p. F16).

7. Internal view adult left valve. R-343.21 m. Hypotype USNM 184341.

8. Dorsal view adult carapace. R-338.94 m. Hypotype USNM 184338.

9. Anterior view adult carapace. R-338.94 m. Hypotype USNM 184340. 

10-12. Bairdoppilata planolata Holden, n. sp. sensu stricto (p. F17).

10. Right valve lateral view adult carapace. R-284.00 m. Paratype USNM 184358.

11,12. Dorsal and anterior views of adult carapace. R-343.05 m. Holotype USNM

184359. 

13-16. Bairdoppilata planolata ventrocaudata Holden, n. sp., n. subsp. (p. F18).

From R-311.35 m. 

13,14,16. Dorsal, anterior, and lateral views of adult left valve. Holotype USNM

184360.

15. Internal view adult right valve. Paratype USNM 184361. 

17-19. Bairdoppilata planolata magnumcaudata Holden, n. sp., n. subsp. (p. F18).

Dorsal, right valve lateral, and anterior views of adult carapace. R-311.81 m. Holotype USNM 184362. 

20,21. Bairdoppilata sp. aff. B. bradyi (Bold) (p. F17).

20. Dorsal view adult carapace. R-31.55 m. Specimen USNM 184357.

21. Internal view adult left valve. KR-12.19 m. Specimen USNM 184356. (See pi. 

1, fig. 1, for lateral view.)
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 9 

6

PARANESIDEA AND BAIRDOPPILATA
PLATE 10

FIGURES 1,2. Pontocyprellal sp. 1 (p. F20).

Right valve lateral and dorsal views of adult carapace. R-287.43 m. Specimen

USNM 184384. 

3, 4. Paracypris sp. cf. P. rosefieldensis Howe and Law (p. F19).

Right valve lateral and dorsal views of adult carapace. R-320.50 m. Specimen USNM

184378. 

5. Caudites sp. (p. F20).

Lateral view penultimate right valve. R-31.55 m. Specimen USNM 184388. 

6,7. Macrocyprina gracilis (Brady) (p. F19).

Right valve lateral and dorsal views of adult carapace. R-317.90 m. Hypotype USNM

184368. 

8,9. Pantocyprellal sp. 2 (p. F20).

Dorsal and right valve lateral views of adult carapace. R-320.96 m. Specimen

USNM 184386. 

10,11. Potamocypris"! sp. (p. F19).

Left valve lateral and dorsal views of adult carapace. S-73.46 m. Specimen USNM

184377. 

12-14,19,20. Macrocyprisl sp. aff. M.I dimorpha Hazel and Holden (p. F18).

12. Left valve lateral view adult female carapace. R-320.95 m. Hypotype USNM 

184363.

13. Left valve lateral view adult male carapace. R-343.05 m. Hypotype USNM 184364.

14. Dorsal view adult female carapace. R-320.95 m. Hypotype USNM 184367.

19. Dorsal view adult male carapace. S-44.20 m. Hypotype USNM 184365.

20. Left valve lateral view adult male carapace. R-162.76 m. Hypotype USNM

184366. 

15,16. Aglaiocypris sp. (p. F19).

Dorsal and right valve lateral views of adult carapace. R-317.90 m. Specimen USNM

184382. 

17,18. Paracypris franquesi Howe and Chambers (p. F19).

17. Internal view adult right valve. R-320.95 m. Hypotype USNM 184381.

18. Dorsal view adult carapace. R-320.35 m. Hypotype USNM 184380.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680- F PLATE 10

4

PONTOCYPRELLA1 PARACYPRIS, CAUDITES, MACROCYPRINA, POTAMOCYPRIS1, 

MACROCYPRIS1, AND AGLAIOCYPRIS
PLATE 11

FIGURES 1,2. Anchistrocheles sp. (p. F18).

Dorsal and internal views of adult right valve. S-79.19 m. Specimen USNM 184627. 

3-5. Munseyella inconspicua (Brady) (p. F34).

From S-78.88 m.

3, 4. Dorsal line drawings adult left and right valves. Hypotype USNM 184573.

5. Internal view adult left valve. Hypotype USNM 184574. 

6. Orionina flabellacosta Holden, n. sp. (p. F20).

Internal view adult female right valve. R-344.12 m. Paratype USNM 184393. 

7-9. Pokomyella deformis (Reuss) ? (p. F21).

From R-300.59 m.

7. Right valve lateral view adult male carapace. Hypotype USNM 184394.

8. Dorsal view adult female carapace. Hypotype USNM 184395

9. Internal view adult female right valve. Hypotype USNM 184396. 

10,11. Pokomyella pseudojaponica inflata Holden, n. sp., n. subsp. (p. F21). 

From S-138.23 m.

10. Dorsal view adult carapace. Paratype USNM 184410.

11. Right valve lateral view adult carapace. Holotype USNM 184409.

12. Aurila sp. aff. A. lincolnensis (LeRoy) (p. F22).

Internal view adult right valve. S-152.25 m. Specimen USNM 184423. (See pi. 16, 

fig. 23, for dorsal view.)

13. Radimella polycosta Holden, n. sp. sensu stricto (p. F22).

Internal view adult left valve. S-140.21 m. Paratype USNM 184417. 

14,15. Radimella convoluta (Brady) (p. F21). 

From S-73.46 m.

14. Dorsal view adult carapace. Paratype USNM 184412.

15. Internal view adult broken left valve. Paratype USNM 184413. 

16. Radimella polycosta rugosa Holden, n. sp., n. subsp. (p. F22).

Internal view adult male right valve. R-l73.28 m. Paratype USNM 184420. 

17,18. Aurila sp. (p. F23).

External and internal views of adult right valve. R-73.46 m. Specimen USNM 184426. 

19-21. Pokomyella pseudojaponica Holden, n. sp. sensu stricto (p. F21).

Internal and dorsal views of adult left valve and dorsal view adult right valve. S147.37 m. Holotype USNM 184398.
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 680-F PLATE 11

ANCmSTROCHELES, MVNSEYELLA, ORIONINA, POKORNYELLA,

100 p.

AURILA,A^D RADIMELLA
PLATE 12

FIGURES 1-4. Hammatocytherel sebastianensis (Bold) (p. F28). 

From R-318.67 m.

1,4. Dorsal line drawing and internal view adult left valve. Hypotype USNM 

184504. (See pi. 3, fig. 2, for lateral view.)

2. Dorsal line drawing adult right valve. Hypotype USNM 184505. (See pi. 3, fig. 

3, for lateral view.)

3. Central muscle-scar pattern adult left valve. Hypotype USNM 184508. 

5. Hermanites tschoppi (Bold) (p. F27).

Lateral view adult female right valve. R-173.28 m. Hypotype USNM 184491. 

6,7. Tenedocythere turda Holden, n. sp. (p. F25). 

From R-317.37 m.

6. Dorsal view adult carapace. Holotype USNM 184456.

7. Internal view adult left valve. Paratype USNM 184457.

8. Jugosocythereis canaliculate Holden, n. sp. sensu stricto (p. F24). 

Dorsal view adult carapace. R-22.25 m. Paratype USNM 184444.

9. Quadracythere trijugis Holden, n. sp. (p. F23).

Internal view adult left valve. S-140.21 m. Paratype USNM 184434. 

10-12. Tenedocythere quadranodosa Holden, n. sp. (p. F26).

10. Internal view adult left valve. S-140.21 m. Paratype USNM 184462.

11. Dorsal view adult left valve. S-141.73 m. Paratype USNM 184459. (See pi. 5, 

fig. 19, for lateral view.)

12. Dorsal view adult right valve. S-141.73 m. Holotype USNM 184460. (See pi. 5, 

fig. 20, for lateral view.)

13. Tenedocythere setigera Holden, n. sp. (p. F26).

Internal view adult left valve. R-338.94 m. Holotype USNM 184465. (See pi. 3, fig. 

10, for lateral view.)

14. Jugosocythereis pannosa (Brady) (p. F25).

Internal view dorsally broken adult left valve. S-152.40 m. Hypotype USNM 184476. 

15-17. Jugosocythereis lactea (Brady) (p. F25).

15,16. Dorsal view adult left and right valves. R-31.55 m. Hypotype USNM 184453.

17. Internal view adult left valve. S-73.46 m. Hypotype USNM 184454. 

18,19. Neocaudites sp. (p. F28). 

From R-307.39 m.

18. Dorsal view adult carapace. Specimen USNM 184501.

19. Right valve lateral view adult carapace. Specimen USNM 184502.

20. Jugosocythereis canaliculata reticulata Holden, n. sp., n. subsp. (p. F25). 

Dorsal view adult carapace. S-97.84 m. Paratype USNM 184447.

21. Hermanites sp. aff. H. barri (Bold, 1960) (p. F28).

Dorsal view dorsally broken adult right valve. S-148.74 m. Specimen USNM 184493.

(See pi. 4, fig. 24, for lateral view.) 

22,23. Occultocythereis sp. (p. F29).

22. Right valve lateral view adult carapace. R-283.46 m. Specimen USNM 184495.

23. Dorsal view adult carapace. R-295.81 m. Specimen USNM 184496.
PROFESSIONAL PAPER 680-F PLATE 12

HAMMATOCYTHERE ?, HERMANITES, TENEDOCYTHERE, JUGOSOCYTHEREIS, QUADRACYTHERE, NEOCAUDITES,

AND OCCULTOCYTHEREIS
PLATE 13

FIGURES 1,2. Platycosta amicus Holden, n. sp. (p. F29).

1. Dorsal view adult male carapace. R-320.35 m. Paratype USNM 184499.

2. Internal view adult male right valve. S-45.11 m. Paratype USNM 184500. 

3,4. Hermanites tschoppi (Bold) (p. F27).

3. Dorsal view adult female carapace. S-147.37 m. Hypotype USNM 184487. (See 

pi. 4, fig. 7, for lateral view.)

4. Internal view adult male left valve. S-141.73 m. Hypotype USNM 184486. (See

pi. 4, fig. 8, for lateral view.) 

5-7. Cyprideis beaconensis (LeRoy) (p. F29).

5. 7. Internal and dorsal views of male right valve. S-74.22 m. Hypotype USNM 

184510. (See pi. 6, fig. 21, for lateral view.)

6. Dorsal view adult female left valve. S-78.49 m. Hypotype USNM 184511. (See

pi. 6, fig. 23, for lateral view.) 

8,9. Semicytherura sp. (p. F30).

Right valve lateral and dorsal views of adult carapace. R-320.95 m. Specimen USNM

184512. 

10-12. Bythoceratina sp. (p. F30).

Lateral, internal, and dorsal views of adult posteriorly broken right valve. S-45.11 m.

Specimen USNM 184515. 

13,14. Hemicytherura pentagona Hornibrook (p. F30).

13. Right valve lateral view adult carapace. S-140.21 m. Hypotype USNM 184513.

14. Dorsal view adult carapace. S-140.67 m. Hypotype USNM 184514. 

15-17. Parakrithella robusta Holden, n. sp. (p. F30).

15,17. Dorsal line drawing and internal view adult male left valve. S-140.21 m.

Paratype USNM 184522. 

16. Dorsal view adult female right valve. S-141.73 m. Paratype USNM 184519. (See

pi. 6, fig. 15, for lateral view.) 

18,19. Paracytheridea sp. (p. F30).

18. Lateral view adult left valve. R-320.50 m. Specimen USNM 184516.

19. Dorsal view adult left valve. R-320.35 m. Specimen USNM 184517. 

20,21. Callistocythere sp. 1 (p. F31). 

From S-147.37 m.

20. Dorsal view adult right valve. Specimen USNM 184530.

21. Lateral view adult left valve. Specimen USNM 184529.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680 -F PLATE 13

4

PLATYCOSTA, HERMANITES, CYPRIDEIS, SEMICYTHERURA, BYTHOCERATINA, HEMICYTHERURA, 

PARAKRITHELLA, PARACYTHERIDEA, AND CALLISTOCYTHERE
PLATE 14

FIGURES 1,2. Callistocythere crenata (Brady) (p. F31). 

From S-44.20 m.

1. Internal view adult right valve. Hypotype USNM 184528.

2. Lateral view adult left valve. Hypotype USNM 184527. 

3. Loxoconcha antillea Bold diffusia Holden, n. subsp. (p. F32).

Internal view adult male left valve. R-318.52 m. Paratype USNM 184550. 

4-6,17. Loxoconcha antillea Bold sensu stricto (p. F32).

4. Dorsal view adult male carapace. S-140.21 m. Hypotype USNM 184545.

5. Dorsal view adult female carapace. S-140.21 m. Hypotype USNM 184544.

6. Internal view adult female left valve. S-140.21 m. Hypotype USNM 184542. (See

pi. 4, fig. 10, for lateral view.)

17. Dorsal view adult female carapace. R-283.46 m. Hypotype USNM 184541. 

7,8. Callistocythere sp. 2(p. F32).

Left valve and dorsal views of adult carapace. R-320.95 m. Specimen USNM 184531. 

9 11. Loxoconcha uranouchiensis Ishizaki (p. F32).

9. Internal view adult female left valve. S-44.20 m. Hypotype USNM 184552.

10. Dorsal view adult male carapace. S-73.47 m. Hypotype USNM 184553.

11. Lateral hinge view adult female right valve. S-78.88 m. Hypotype USNM 184554. 

12-15. Loxoconcha longispina Key (p. F32).

12,14. Right valve lateral and dorsal views adult female carapace. S-79.19 m. Hypotype USNM 184536. 

13. Internal view adult male left valve. S-78.88 m. Hypotype USNM 184532. (See

pi. 5, fig. 3, for lateral view.)

15. Dorsal view adult male carapace. S-147.37 m. Hypotype USNM 184538. 

16. Jugosocythereis canaliculata Holden, n. sp. sensu stricto (p. F24).

Internal view adult left valve. S-45.11 m. Holotype USNM 184442. (See pi. 4, fig.

22, for lateral view.) 

18-20. Loxoconcha sp. 1 (p. F33).

18. 20. Dorsal and internal views of adult female left valve. S-44.20 m. Specimen 

USNM 184555.

19. Lateral view adult male right valve. S-73.46 m. Specimen USNM 184556.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 14

CALLISTOCYTHERE, LOXOCONCHA, AND JUGOSOCYTHEREIS
PLATE 15

FIGURES 1,2. Loxoconchella sp. (p. F33).

Dorsal and internal views of adult posteriorly broken right valve. S-140.21 m. Specimen USNM 184565. 

3,4. Paradoxostoma sp. 1 (p. F34).

Dorsal and right valve lateral views of adult carapace. S-49.19 m. Specimen USNM

184567. 

5,6. Paradoxostoma romei McKenzie (p. F33).

Internal and dorsal views of adult left valve. R-31.55 m. Hypotype USNM 184566. 

7,8. Pellucistoma sp. (p. F34).

Internal and dorsal views of adult left valve. R-163.6 m. Specimen USNM 184569. 

9-12. Xestoleberis sp. cf. X. granulosa Brady (p. F34).

9,10. Internal and dorsal views of adult left valve. S-78.88 m. Specimen USNM 

184585.

11. Dorsal view adult right valve. R-31.55 m. Specimen USNM 184586.

12. Anterior view adult carapace. S-78.88 m. Specimen USNM 184584. 

13,14. Paradoxostoma sp. 2 (p. F34) .

Internal and dorsal views of adult left valve. R-320.34 m. Specimen USNM 184568. 

15-18. Xestoleberis sp. 2 (p. F36). 

From S-140.21 m.

15-17. Internal, anterior, and dorsal views of adult left valve. Specimen USNM 

184600.

18. Dorsal view adult right valve. Specimen USNM 184601. 

19-22. Xestoleberis sp. 1 (p. F35). 

From S-147.37 m.

19. Anterior view adult male left valve. Specimen USNM 184597.

20. Internal view adult female left valve. Specimen USNM 184596.

21. Dorsal view adult female left valve. Specimen USNM 184598.

22. Dorsal view adult male right valve. Specimen USNM 184599. 

23-25. Xestoleberis sp. cf. X. curta (Brady) (p. F35). 

From S-73.41 m.

23. Dorsal view adult female left valve. Specimen USNM 184590.

24. Dorsal view adult female right valve. Specimen USNM 184591.

25. Anterior view adult female carapace. Specimen USNM 184592. (See pi. 17, fig. 

1, for lateral view.)
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680 -F PLATE 15

5

LOXOCONCHELLA, PARADOXOSTOMA, PELLUCISTOMA, AND XESTOLEBERIS
PLATE 16

FIGURES 1-3. Xestoleberis sp. cf. X. briggsi McKenzie (p. F35). 

From R-320.95 m.

1. Dorsal view adult female carapace. Specimen USNM 184588.

2. Right valve lateral view adult female carapace. Specimen USNM 184589.

3. Anterior view adult female carapace. Specimen USNM 184587. 

4-7. Xestoleberis tumefacta Brady (p. F34).

4. Internal view adult right valve. S-45.11 m. Hypotype USNM 184580.

5. Dorsal view adult left valve. S-44.20 m. Hypotype USNM 184581.

6. Dorsal view adult right valve. S-44.20 m. Hypotype USNM 184582.

7. Anterior view adult carapace. S-44.20 m. Hypotype USNM 184583. 

8, 9. "Cythere" sp. aff. "C." caudata Brady (p. F36).

8. Right valve view adult carapace. R-320.34 m. Specimen USNM 184576.

9. Dorsal view adult carapace. R-320.34 m. Specimen USNM 184575. 

10-13. Cytherella sp. 2 (p. F37).

10,13. Internal view and dorsal line drawing of adult female right valve. S-152.25 m. 

Specimen USNM 184608.

11. Left valve lateral view adult female carapace. S-151.79 m. Specimen USNM 

184607.

12. Dorsal view adult female left valve. S-152.25 m. Specimen USNM 184609. 

14,15. Ostracode sp. (p. F36).

Dorsal and right valve lateral views of adult (?) carapace. R-317.91 m. Specimen

USNM 184577. 

16. Cytherelloidea semipunctata Holden, n. sp. (p. F37).

Dorsal view adult female carapace. R-284.47 m. Paratype USNM 184619. 

17, 21. Cytherelloidea sp. cf. C. umbonata Edwards variation (p. F37).

17. Left valve lateral view adult female carapace. R-173.28 m. Specimen USNM

184615. 

21. Dorsal view adult female left valve. R-338.94 m. Specimen USNM 184616. (See

pi. 6, fig. 9, for lateral view.) 

18,19. Cytherelloidea sp. 2 (p. F38). 

From R-318.36 m.

18. Dorsal view adult male carapace. Specimen USNM 184626.

19. Dorsal view adult female carapace. Specimen USNM 184625. 

20. Cytherelloideat japonica Ishizaki (p. F38).

Dorsal view adult broken female (?) right valve. S-44.20 m. Hypotype USNM

184628. (See pi. 6, fig. 12, for lateral view.) 

22. Aurila sp. aff. A. lincolnensis (LeRoy) (p. F22).

Dorsal view adult carapace. S-152.25 m. Specimen USNM 184423. (See pi. 11, fig.

12, for internal view.) 

23,24. Cytherella sp. 1 (p. F36).

Lateral and dorsal views of adult female right valve. R-288.65 m. Specimen USNM 

184606.
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 680-F PLATE 16

XESTOLEBERIS, "CYTHERE," CYTHERELLA, CYTHERELLOIDEA, AURILA, AND OSTRACODE SP.
PLATE 17

FIGURE 1. Xestoleberis sp. cf. X. curia (Brady) (p. F35).

Right valve lateral view adult female carapace. S-73.46 m. Specimen USNM 184592.

(See pi. 15, fig. 25, for anterior view.) 

2-6. Xestoleberis datelinensis Holden, n. sp. (p. F35).

2,4. Right valve lateral and dorsal views of adult male carapace. R-317.37 m.

Holotype USNM 184594.

3,5. Dorsal and anterior views of adult female carapace. R-317.37 m. Paratype 

USNM 184593.

6. Internal view adult female left valve anterior. R-318.36 m. Paratype USNM

184595. 

7-10. Cytherella textum Holden, n. sp. (p. F36).

7. 9. Dorsal and left valve lateral views of adult female carapace. R-284.00 m. Holotype USNM 184604.

8. Dorsal view adult male carapace. R-284.00 m. Paratype USNM 184605.

10. Internal view adult male right valve. R-335.74 m. Paratype USNM 184603. 

11-14. Quadracythere aequabilis Holden, n. sp. (p. F24).

11. Internal view adult male left valve. R-320.35 m. Paratype USNM 184437. 

12, 13. Dorsal and right valve lateral views of adult female carapace. R-336.58 m. 

Holotype USNM 184439.

14. Right valve lateral view adult male carapace. R-320.35 m. Paratype USNM

184436. 

15-19. Parakrithella eopacifica Holden, n. sp. (p. F31).

15. Internal view adult male right valve. R-318.21 m. Holotype USNM 184523.

16,18,19. Right valve lateral, dorsal, and anterior views of adult female carapace.

R-320.95 m. Paratype USNM 184524. 

17. Right valve lateral view adult male carapace. R-320.95 m. Paratype USNM

184525.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 680-F PLATE 17

XESTOLEBERIS, CYTHERELLA, QUADRACYTHERE, AND PARAKRITHELLA