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DEPARTMENT OF THE INTERIOR

MONOGRAPHS

OF THE

UNITED STATES GEOLOGICAL SURVEY

WOE UWE IG LW

WASHINGTON van
GOVERNMENT PRINTING OFFICE 24333 os
1915

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Direcror

THE

MESOZOIC AND CENOZOIC ECHINODERMATA
OF THE UNITED STATES

BY

WILLIAM BULLOCK CLARK

AND
MAYVILLE W. TWITCHELL

WASHINGTON
GOVERNMENT PRINTING OFFICE
LG) il &

IBRERACE ee 52-63 = oo 5c

CONTENTS.

Part [.—THE Mrsozorc EcHINODERMATA, BY WiblIamM BuLLocK CLARK..............-......--.-.-----+-----

Introduction. ..-..-.

Geologicyandiaeoonaphiciran oe! ser seers. aie tcle sist are oo moons pcre easier SSeS ey ope PN eee ores

Bibliography -- -

irrass ce eli oderin a baeeers ket mics ait a) -)te NEP oer A PSN eevee ciated aed Ae SO ee a

Agia AED. .schos cease soos SABO EEE SAO Oe eee eee TEN eC ERE te ean SR eer nie

Echinoidea-.---

Ophiolepididsaes ae cesa sass asee ees see eee eae st Bla Sane tala cake eee eee ee Na ge ne te

Echinoidea..-.-

Jelemulens Pini bos a deorcetpon dee eet cme aa Aes Neca at een er Ate eee ents at SAO oe eee
Tad emia saber eee ae sets es Ieee sya ape ait pays ahs =a CIS) 5 is Senses Sg cetera eee ee
Be Fe ch TT cle ap enters var Sy eye eae = ea Sekt cya men sm NY cpc cha se Spee MDS Ao pa aden arse yas
IP EPRICE coana seen das baosHdaasssaneuaadauaspedee euandqncoceaacsstennsebacoss esapoe sense

Cassidulide

Cretacecouspl chimod ermia tals tetas ete os sara r ae chatted a adhe fale crapaiel op ej orebe paler ee te Sees Seaton (oy eS aa a

Crinoidea. -----

WY ehesUh HOES 5505 5G Sete epee ea RS SLi sree Retr tee RSS MU hen eae ete tue hh St Nase
TB OULOUE UL GEIL Satara e cele sieley ofa, ei Tectia oid NE a ayes) ay cee inset he ore en ae gee EE
S tellLenold ca seamen Pao Sok Sh. ot Samay barras Monin Se ee cine Seles aaete Cee OR Pn eet
FARINRO) KOO MACH OSS © SaaS SERS E ease SEES ane ee ee aaa ey ene Aas emer eee A carey a
Rentaconasterid smash seins os, ASU < soe a2 ate nte Die 52 e ie ale ob Se ann he Sete ees ae a et

Atheneide -

Ophiolepidi
Echinoidea-..--

GS Sao cS EIN SESE Oe Se ee IN IER SC eae carne Cees at ate Sw cr Ones Bese ty

ONG TENCE Tes cescdc coeundoss sb qoa = HES oR Oa SEE E REREAD HeSe te aSbetoe Oso e pat nost seuGemannouse scene

Diadematid

Cisooccogmcascced wesc og eer eee PONS EEO Ea ooo mDe eerie Scseanostosedamssssosososaean

Dplopodird eekeemes ee meee sue <r ee yayaisre w)si2 I Sears isl SSE RS OS ee er
(Oyj VOSS EL le ee a eee ee eee
Mri le Chil dgezeaeten yaaa tae es lo ee etc Ariss fiesa sian se /-vciSjem eenyetc eS e eee er ree
I EASING sa socbc sod eo col: Son sc unepetne Heme BRn as aeor noob ate RUSS sees SAEe an Graseetenoe
Glypeas tric soot ware ee Ep eer ta) slac Sank oe ae ak Sere ae Meee me Le os ete es 7 acy a ee at ya
IDCs odode duodes S25 ase oR RABE OCU Aaa pene aaa aon ogtmauobBeraous=pUsseso.dua=eecuenerer
INWEOGINNC EDs 5 oe cceketescg RanS> ss RUC GER ES DUD SE HEbe ean cad audanb Udo dae cases eareascoquBeeae

Cassidulidze

Hehinoconyjthid seseeeenenaee ty ee tec ie sic ces eee ge teh irae cele isapap are ree eny a eet tyaL ot Le

Spatangidee

bow Re

bo bp bo

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58

4

CONTENTS.

Part I].—Tue Cenozoic EcoinopERMATA, BY WitLI1AM BuLtiock CLARK AND Mayvitie W. TwitcHeELt...

Imtroductone <0 7-26 Senate See eects aoe Soe ea se ESCA OHS Ab ee SA ase 5 oon e
Geologiciand!geographicirange rsa eee ers ese eee eee eta Te eee eee
1h obLeCagah th ee Raa obeeaHoe See HEHE Ns SAGEM cw cosHsoononSep Kb soscanodse doc dooaonoEdonodsscsseaods

ByOGene xB) chin erm atest arses atm Sean ee aa ay PET aad Pa et te
C@rinoldea® 6 28 ssa Sepa aie Se eee ree yor ee ee Sere ree ep ota ts eee EN SAIN 2 je Ry a yg ie ag

(Amtbed omid 20's sees es ipl bie al Ree age Sern SRT, por sy testers aetna) PS ve REN eed SD A ea ee
Stelleroideas eso s2 he. Secchi Gee Oa ee
Aig teril d 80 ins 5/502 Ik ela a ay ea aS LOY 0 AU ISS ede ee ne Ppctersets
Bchino1d Gaisn20: 28 Pare hs SS eas ore Se See Ty Sa (eee LE Erg ge aT SS
Cidaridee:...t-b Seccccse SS i Se BRIG Sepa SPA UO EOE I RI ape Nerd yee ee ee
WArbaciide 2. 2308 Wor Si Ue Doel ia Sea kW EER Cte cep OS ee var RL OD no
Oho oso} COE Sete eeedes RoeREe pao n aE cds oma bOctaesmocasacuowo sec doRmenunEbocosudecasiocesue
Hbbahalkeeloubl: paeeeEasEE Hae toh b eae OAs Eon aanaBaEMebdene od ad auo ca ndsepenodtousoognosdeacnaS
Bibrilartd dees nS sae eye Sk NR oc La pc ett AN ATW DR re gee RO
Tuager eum ae je !2 yc chc =a, Si ev Lice ach eto AR pea chy eg eNO STA aS UN DEL a ae
Soubeldtd ce 20.08 5 ses se pe Mie oe 212 a iets Ue 220 ee eva et en Ue aL a rh Le ee ee BN
Clypeastridee Nese n eit Seater ers PERSON Ane comes so okad Her EO RABE HEae 2h ee arate Eee
@asst ol whic eee ifs 2. See as Na Ree RSs By AU SUE ORY amg ear Pel cee Usted DUNC 7 LA ARC rae ne
Spartamaldae 2's se ee AS pein a teak pepe Vii eon, cx ote ea aes yaa ENT nye EU Seg

Oligocene Hehinoderma ta: 2.4. eis c/o ye Ss A eS pe ote SE ES og EVEL OL APO SAL Eee

Beehimoid @aj:i's gee 5 ysis'e Seed Ste AS as Sia es asco ei Pe SE es ete eS SEs Rp Ee Tes Se
OrKG EeWa 6 yeep poe eg a an eer ial aU Mel. MEN en ora Gd aman oaise BAS AN Ei ale et eee ees
2 Nid OE KOOKS eee ere ee een tye bes Gi ere ei tA eal IU He SU aR oe Gog G
Gypplosomiartidl cee <5 se e BeR ee RE eas SN ke a Oe RPC re eee
Driplechimidee'. 22 12542) 525k Se SES eee NO TO Ty ee 8, SOE RY SAP pee eye oe cree NE Ute ate St
[Moe ablc ls eee ees A eee Aa eRe NS Lar omnia oc ma Ghc ana aM ees aE oles dataae
EE erhi bs be eee REE eA Ae Eee Bea Stns e As SOE Se SME SOS 2.550 dace RS aae eas MACS ene eta aoe:
INGicleolitid sey tes 2S pee eas ie Re Ble DUR SNS eS UL at At AeA ese BN, a a ea
(Wetseichin Li se eps ae os SIN NE eee ER oY EVN Te 21 ee
SyoenicnIl sal: pean eels We ee Me USE Ne See OA Mera veil eldcayn ea baenguHananeEsbaddecs Saas
ShiAIH) NOCHE Rae Ag oSEEs Ae Mes Seen es KOMEN a Sass Sc ecdamesh Shs Sobdas SECU ooerbaDModas uae: oat

WOO eine ISCaunnocleminnia, <socoscsecocsocceccsoaescceceoqseasuacue Heaths Sp NRE RUT Nala Bye Ape AGL re aE

Sitellerordiea sss tepals ae SM PU ced alee she Sa Leal ratte Ma aan ep RR INR Ve Dy A ee
DNS erate (2 Tae Oe ap lets Ea Oe ales eae er ane Ag ne es a oe CG WG ric OIGO DERE Caan acoaksoouse
Qplvoderma hides. 2/05 e ees ese Se the aS se Neg Poe sear) en eR Pe Ce Do So
72Gi0} NOUN Woke Meee aR AC ARHEAR REO SAAS m RSE. Guid anomie SoS OHan Sabon aapeBe nS MaS Roe ds Sepcies 6

BY CHT TA OVC Cay pe oy Pe eset ds SN ESO ay CI pet ee
Giarchi BR LE I Bee Ce MU hSLAE ak ce apo an Qcca = eh a ato INCE ©) LE Ly
UNTel OF: KEVIN yee st aa pn menses ee apa PWN GU De, actos mle Sa a nett ea Ue ts cre Es tate eee
Mrbple chums dee o/s 6 see oe a ee Pe ere eee Sete Sarge os ech ole mvAey AL are as coats ate Ue EE
HQall ond eveanit be Ree ee pe ermal er ROE he A se Ler See Se ee ead le hee ee ee eho
Scutellide......-- Wp Hee Eater RG Ma Rea at Sela nk HEA ADEM ARE HAUSE Hog keee 5 <=
Clypeastride......-...--- Sasa BEND Ol ON alt SVN DACA ere (2 eR Pc So eee
G@assrdmlidae esis he citi 5 ye eso 1a CER AE as Soa ns eral a FAC Aa Sloe pate aes lege ae
SHORING PIS A cabansasadsnodsacs Be ae ee a I A TNC U I) to a Pe Ma PU RE BS este Set

Pliocene) Hehinodermatas s-- 2.225252 2222-= =i ska Peta sd OM Sa ea Me NIL SN ah ANZ NE a
Echinoidea...-.-. PINE TTS LE SRA os IS RAR OE eg LO

Stronoylocembtro tid cee 235 Ne AIR Oe ee RI EI SSRs Moh a epee USE a aOR a Eee i
PSK eynigif=) Uo Fz ye ea an PIE a ou ast eG a LL ns ee Ea ne as @Ucitts ce ah ate meme
@lypeastrticles eee bey isa ee eI DU hE aI) ROE AG ig a ea RE Ee EPS
asst ee ee sic ar bs fe Be Eg EE Ne nae Pe ae ye
Spatamordescete Ro sy Ses Ai aU Ge RUINS ESS AySH OR bees eaten aa any tel fee eg te

Pleistocene Hchinodlerma tachi ea Ns NG Oana aye crouched Sh cP A SSE el ere oe eR EE aE

Stell erovd ea es: etek ICRA ees ant se mee EIU )ECS ON aU SN a Sa Rarer: Rego
Asteriid eter ene nee | Boeear ben enessaodcon seccusdadscoeeascebeneenodseccasdsccaneassereueccsse
CHIN OLA a2 2 cafe eh ay LS rr Bala a tI ar Ne a ES
Mrigole chit ees a) hele Petes Soy ee aie Ie ape Nn nad ee gee oP gen
Sitron gy locemtino tides 9-5 so eee ea RENEE fe oes Ra eel eee
Sewmtellidiee ys eo Is coe a en a Re ee Bite iaeei

220

wmpmwnmwnww bw bv
Nowwhw Wb Ww bw wv
co ht bt bt by bw Ee

ww
wy
aI

337

ILLUSTRATIONS.

Peas C\MlleeMesozorcrand Cenozoic) Lichinod ermatal eee ci--\-t eee ise -|e eee ie eee ee ees 228-336
CVIII. A, Astrodapsis tumidus Rémond in matrix, Santa Margarita formation (upper Miocene),
Nacimiento River, San Luis Obispo County, Cal.; B, Dendraster gibbsii (Rémond) in upper

Miocene (?) beds, K. W. Jones ranch, Kings County, 20 miles southeast of Coalinga, Cal....._-- 336

a
pan
uscd 2k

*

PREFACE.

The study of the Mesozoic and Cenozoic Echinodermata of the United States was commenced
by the senior author of this paper under the auspices of the United States Geological Survey in
the autumn of 1890 and has been continued with frequent interruptions to the present time.
During recent years he has had associated with him, in the study of the Cenozoic forms, Dr. M. W.
Twitchell, formerly a graduate student at Johns Hopkins University and now assistant State
geologist of New Jersey, who has confined his investigations chiefly to the Clypeastrina and
Asternata. Several papers containing results of this study have been prepared by the senior
author, the most important being one entitled ‘‘The Mesozoic Echinodermata of the United
States,’’ which was published in 1893 as Bulletin 97 of the United States Geological Survey.
Other contributions have appeared from time to time as the work has proceeded.

Few American paleontologists have investigated the Echinodermata, and no one of them has
hitherto attempted a general systematic study of the Mesozoic and Cenozoic representatives of
this group. Much confusion has therefore existed as to the specific and generic relations of many
of the forms, and their geologic distribution has been in much doubt. Some of the forms are
very numerous, and because of their wide geographic and restricted geologic range are valuable
in determining questions of correlation. The revision presented in this contribution should
therefore be of some value in stratigraphic geology.

No attempt has been made by the authors to modify materially the recent classifications of
the Echinodermata, which are based on exhaustive study of far greater and much more repre-
sentative materials than those afforded by American deposits. The authors have followed very
closely in their major classification that of F. A. Bather in ‘‘The Echinodermata,” in Lancaster’s
“Treatise on zoology,” and in their generic usage that of P. M. Duncan in his ‘‘Revision of the
genera and great groups of the Echinoidea.”

Many courtesies have been extended to the writers in connection with this study, and all the
large collections of the country have been put at their disposal. Among the more extensive
collections used have been those of the United States Geological Survey, United States National
Museum, Academy of Natural Sciences of Philadelphia, American Museum of Natural His-
tory, Wagner Free Institute of Science, Museum of Comparative Zoology of Harvard College,
Peabody Museum of Yale University, Cincinnati Society of Natural History, Walker Museum,
Carnegie Museum, Field Museum, Boston Society of Natural History, Johns Hopkins Uni-
versity, Williams College, University of California, Leland Stanford Junior University, Amherst
College, Maryland Geological Survey, New Jersey Geological Survey, Texas Geological Survey,
Alabama Geological Survey, P. de Loriol, and Robert T. Jackson.

The authors desire particularly to express their appreciation for valuable personal aid
rendered by numerous paleontologists, among whom should be especially mentioned T. W.
Stanton, of the United States Geological Survey; J. W. Gregory, of the University of Glasgow;
W. H. Dall, of the United States National Museum; Robert T. Hill, formerly of the United
States Geological Survey; Frank Springer, of the United States National Museum; John C.
Merriam, of the University of California; and Ralph Arnold, until lately of the United States
Geological Survey.

Most of the illustrations have been made under the direction of J. L. Ridgway, of the United
States Geological Survey. Many-of the earlier drawings from Bulletin 97 (The Mesozoic Echino-
dermata of the United States), made by C. R. Keyes and H. C. Hunter, are incorporated in
this volume.

i

THE MESOZOIC AND CENOZOIC ECHINODERMATA
OF THE UNITED STATES.

By Witiram Buttock Crark and Mayvitte W. Twrrcne..

PART I.—THE MESOZOIC ECHINODERMATA.

By Wiriram Buttock Criark.

INTRODUCTION.
GEOLOGIC AND GEOGRAPHIC RANGE.

The remains of Echinodermata are found in Mesozoic deposits at nearly all horizons and
at widely separated localities but are much more numerous and characteristic in Cretaceous
than in Triassic and Jurassic strata. In several of the Cretaceous formations they are among
the most valuable diagnostic fossils, and at a few localities they occur in vast numbers.

Comparatively few Triassic forms have been found. The most common are crinoid stems
representing the genera Isocrinus and Encrinus, the former appearing in the Lower Triassic of
Idaho, the Middle Triassic of Nevada, and the Upper Triassic of California, and the latter being
confined to the Upper Triassic of California. The echinoids are represented by two species of
Cidaris, which are confined to the Upper Triassic of California. In addition to these a few
indistinct casts, among them asmall, poorly preserved starfish, which has been questionably
assigned to the genus Aspidura, have been found in the Lower Triassic of Idaho.

The Jurassic echinoderms are somewhat more numerous and varied, although they form no
considerable proportion of the known American fossil Echinodermata. The most common
forms belong to the genus Pentacrinus, column joints having been found in Nebraska, South
Dakota, Wyoming, Colorado, Idaho, Utah, and California. The asteroids are represented by
both the Ophiuridze and the Stelleride, specimens haying been found in Wyoming, South
Dakota, and Utah. The echinoids are much more fully represented than in the Triassic. Sey-
eral genera have been recognized, among them Cidaris, Hemicidaris, Pseudodiadema, Stom-
echinus, Holectypus, and Pygurus. Most of the specimens are poorly preserved and are in few
places numerous. The first four genera occur only in California, being found in both the Lower
and Middle Jurassic. One species of Holectypus occurs in Texas and another in Montana.
Pygurus has been found only in Texas.

The Cretaceous echinoderms are very numerous in certain areas. <A great variety of types
is represented and much of the material is splendidly preserved. Many of the species are nar-
rowly limited in geologic range and are therefore important as type fossils.

The crinoids are represented by Uintacrinus, Marsupites, Pentacrinus, and Rhizocrinus,
the first named having afforded a great number of remarkable specimens in the Niobrara chalk
of Kansas. Springer has made this material the subject of an elaborate monograph, and most
of the great museums of the world contain beautiful specimens from the now famous locality
in Kansas.

10 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The stelleroids contain representatives of both the Ophiuroidea and the Asteroidea, the
genera Ophioglypha, Astropecten, Goniaster, Pentagonaster, and Pentaceros being found. The
material comes from widely separated areas in New Jersey, Texas, and Wyoming.

The echinoids are very numerous, both the regular and irregulag types being well repre-
sented. Both the Lower and Upper Cretaceous deposits of Texas contain many species and vast
numbers of individuals at several horizons; and the Upper Cretaceous of the Atlantic and eastern
Gulf coasts, particularly in New Jersey, North Carolina, Alabama, and Mississippi, although
fully characterized by its echinoid fauna, affords many forms. The western interior and
Pacific coast Cretaceous contains a much smaller representation of echinoid types.

Among the Lower Cretaceous genera represented, more particularly in Texas, are: Cidaris,
Salenia, Hypodiadema, Goniopygus, Pseudodiadema, Diplopodia, Cyphosoma, Holectypus,
Pyrina, Enallaster, and Hemiaster. Outside of Texas very few Lower Cretaceous echinoids
have been recognized. The Horsetown formation of California contains a few forms.

The Upper Cretaceous of Texas contains a large echinoid fauna and some of the genera
possess many species. They are: Cidaris, Leiocidaris, Leptarbacia, Orthopsis, Heterodiadema,
Cottaldia, Diplopodia, Cyphosoma, Micropsis, Holectypus, Echinobrissus, Cassidulus, Anan-
chytes, Cardiaster, Holaster, and Hemiaster.

The Upper Cretaceous of the Atlantic and Gulf coasts has afforded representatives of the
following genera: Cidaris, Salenia, Pseudodiadema, Coptosoma, Psammechinus, Echinobrissus,
Trematopygus, Botriopygus, Cassidulus (many species of which have been recognized), Catopy-
gus, Echinanthus, Ananchytes, Cardiaster, Hemiaster, and Linthia. Much the larger number
of Atlantic coast forms have been found in the New Jersey Cretaceous, especially in the Vincen-
town sand of the Rancocas group, which is regarded as probably of Danian age. The western
interior and Pacific coast areas contain few representatives of the echinoids, most of the species
belonging to the genus Hemiaster.

The absence of species identical with those of other continents and particularly of Europe
renders impossible a detailed correlation of American and foreign horizons on the basis of their
echinoderm faunas. However, genera represented in the main divisions of the Mesozoic in
America are with scarcely an exception similar to those typical of the same divisions elsewhere.

The accompanying tables show the stratigraphic positions of the more important American
Mesozoic formations, the geologic distribution of the Mesozoic Echinodermata of the United
States, and the stratigraphic distribution of the Cretaceous Echinodermata of Texas.

11

INTRODUCTION.

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12 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Geologic distribution of the Mesozoic Echinodermata of the United States.

an z Lower | Upper
Triassic. | Jurassic. | Creta- Creta-
P ceous. ceous.

Crinoidea:
Dicyclica—
Tnadunata—
Dendrocrinoidea—
Pentacrinida— 0
2 Tsocrinus smithi Clark ..-
Tsocrinus californicus Clar!
TSOCLINUSISDeeeee==neeeeeee
Isocrinus knighti Springer --........-.-
Pentacrinus asteriscus Meek & Hayden .
Pentacrinus whitei Clark ...........-
Pentacrinus shastensis Clark . -
Pentacrinus tehamaensis Clark
TELNET UUAIS lA Wal (CHIOV) - = oh oo aaceasosacmookos Sasoccdsesonaoccousoaossessacsssecc
Encrinide—
Dagar S Wy AM CHES so oop pogo cnsaoansacesqdssanNss so otereSeosescsscseabsoessocs SCY Teac | A Do
Uintacrinidea—
Uintacrinus socialis Grinnell
Marsupitide—
DMarrs Up ifes| al Or) CAUSE OTL SC Tyee eae ese ete tata ee ee ee ae ee x
Flexibilia—
Pinnata—
Bourguetiicrinidzee— 3
HIZO crinuslalabarrensishc ewlsariolesepy spree ters eee eee ete see eae eae | ae eae |
IRMizoerimus! cylin dricuspVje llores eyes eee eee te ear eae teers te Se |r ae | Eee pe

XX

Stelleroidea:
Asteroidea—
Phanerozonia—
Astropectinine—
INV AAO TOL (GD) aa HOH PAS IDLOWHYOS 5 Gag casecsoesdascasedosenssessooe a Scoeseess aos pasesescudljsonesnseed|boscbedene x
Pentagonasteridze— \
TES AE OMERLIE ROMO WAU oan conan cocoon same gneeeseseosse4scoeossbeeo so ssqonssoed|ssaecdongn boxcoesesn|bossecebas x
Atheneidze—
Goniastenmamimillatay Gab bese sesee ee eee ene eee eee ee eee enna ee eee eee a eens eee eee esp boca Sonaeecaec se
Pentacerotidw— |
IEG MUN ASO UNS CHEM = Coe gausosacausdecadeodaneor 5 seobdoascodenosstesezececlooseeosscoloscoshe cactus fxd oleae, x
Cryptozonia—

Asteriidax—

ASGAES @) Cholorinrad Werle) — . ssogags taco sees sssasneb acto she sooo ssegesousesoesdlSsossoccs¢ » als EER easel eases cee
Ophiuroidea—
Zygophiure—

Ophiolepididse— :
Ophioglypha utahensis Clark... - 7... .--- 2-888 nn ee
Ophioglypha texana Clark ........ els
Ophioglypha bridgerensis (Meek)

Amphiurida—

FAS pi dural (2) iG altOensis) © lat esses eee eee eee ee eee ee ee eee eee PGi Meera epee sere Seer menc

Echinoidea:
Regularia endobranchiata—
Cidaroidea—
Cidaridee—
(Gidaris|shastensis| Clarks esse ee eeee pees nee eee
Cidaris dilleri Clark ---.
Cidaris californicus Clark
Cidaris taylorensis Clark -
Cidaris plumasensis Clark -
Cidaris tehamaensis Clark -
Cidaris texanus Clark - -
Cidaris walcotti Clark :--
Cidaris splendens Morton ..-
® Cidaris dixiensis Cragin ...-
idaris nahalakensis de Loriol -
Leiocidaris hemigranosus (Shumard) ............-.-----------
Regularia ectobranchiata—
Diademoidea—
Calycina—
Saleniidae—
Salenia texana Credner
Salenia tumidula Clark
Seiler eb Cle es oe bes cesonscoss ocr non eas coons conse couoeseoes s20escSS snes see
Arbacina—
Hemicidaride— rf
Hemicidaris intumescens Clark
Hypodiadema elegans Clark -
“Goniopygus zitteli Clark ....
meptanbacioacciulis Clarkes: ee eee esse eee e eee er ae eee ieee
Diademina—
Orthopsoda—
Orthopsis planulata Clark
Orthopsis occidentalis Cragin
Diadematidze—
Pseudodiademrare ne rsoxi ye Glens Keer ates a eee | eer |
Pseudodiadema texanum (Roemer) -.
Pseudodiadema diatretum (Morton) --
Heterodiadema ornatum Clark %
Cottaldia rotula Clark ........-
1a iGyaahh oferohbaksy Cloeyalhevonl Oheyatbol 6 see cosenecas soadsescccocoss cess easousdeendseesdavallesoosseece
Diplopodiidae—
Diplopodiatathy Cragin ss cee eae ee eee le alia ete elein stella ete fale oe fere eile efoto fafa [folie eels SG lll ean
Diplopodia streeruvitzi Cragin 2.221222... 2 ee on ww nn = fw ne ww ma nw >
Pedinide—
Stomechinus hyatti Clark <- 22. <2 25 oe so ooo cw oe se iw wn em anf nl SCR S| Re ite a ge aes
Cyphosomatidae—
C@yphosoma/hilli Clark: = <=) 52 22. ee wee oe oe ose eal alain ai mall a
Cyphosoma texanum Roemer -
Cyphosoma volanum Cragin -.-.......-.---.....------------------+----------------

INTRODUCTION,

Geologic distribution of the Mesozoic Echinodermata of the United States—Continued.

|

13

Irregularia—

i bel | Lower Upper
Triassic. Jurassic Creta- Creta-
| ceous. ceous.
Echinoidea—Continued. |
Regularia ectobranchiata—Continued. |
Diademoidea—Continued.
Diademina—Continued.
Cyphosomatidae—Continued.
Coptosomarspeciosuml Clankiense ee aceee eae seme cee te see ee te eee eee x
Coptosonia mortoni (de Loriol) x
Micropsis lineatus Clark -.......- x
Echinina— ,
Triplechinidae—
Psammechinus cingulatus Clark x
Pedinopsis symmetrica (Cragin) xX
x

(Retlinopsisspondit Clarks yaaa eee eee eee ee ae eee meee se ee ee

Gnathostomata—
Holecty pina—
Pygasteridae—
Holectypuspealei, Clarkia see: ae ene eie incense sccemeec sae e eee leew ee eens
Holectypus cragini Clark ......
Holectypus planatus Roemer
Cly peastrina—
Clypeastridae—
Echinanthus mortonis (Michelin) -
(Arscutellastercretaceus Cracimisen jasc a tae eet a ee ae ole ee eee ae enn eae
Atelostomata—
Asternata— : |
Echinoneide—
Iya) anal Is EV Bean ee Roa Ss sesoeoansaTecc BHC AaRSe Shes ConEaoceeE Suse ase Sacusesebese |
Nucleolitida—
iBomlopDYeUsalabamensis) Glarkya- oe eser ese se eee sees e eee eee eee eeeeee i
Echinobrissus angustatus Clark -
Echinobrissus expansus Clark -- -
Echinobrissus texanus Clark --..._-
Trematopygus cruciferus (Morton). -- 2 BER eee ae ais
Cassidulidaee— |
Pygurus sp | x

IBY STITT) Ge) & COM CLEATS) CNLOL COLL) ereteraye see see ane ee seyret ictal a ee | oe eee ene !

Catopyeus Ovilormis| Conrad ee eee eee ee eee ESS SO Eee es Sa eas
Catopygus pusillus Clark .-. Ae
Catopygus Williamsi Clark - Bee

CEWON TUS RD Saosscscossesgons dase cousesnesgadb socensusescunoaseasacosSssunobeLebe|becassasins badscasdac |

Cassidulus florealis (Morton) - pad
Cassidulus equoreus Morton . - i is mA
Cassidulus micrococcus Gabb -.- i Faas

Cassidulus subquadratus Conrad
Cassidulus subconicus Clark -..
Cassidulus porrectus Clark .
Cassidulus stantoni Clark ....
Cassidulus intermedius Slocum : -
Cassidulus hemisphericus Slocum
Cassidulus conoideus Clark ......
Cassidulus abruptus Conrad ......-.-.---

(@iGassidulus|subangulatus (Mmmons) eee sop eee ene nee nue ne eee [osecs= Se a5 aan

Sternata—

Echinocorythide— | |
MManchyLestovalis) Glarkysrtectse cence) cialis ee eee ace sees see ene else aie [ete ee ee
Ananchytes texana Cragin . .-
Cardiaster cinctus (Morton)
Cardiaster smocki Clark -._.
Cardiaster curtus Clark ... -

FOINSReTIS IM PlERAS NUMA Meese Aen Meet ee aime ome sk ne nz ee cae ec dleee [Deo Pcie ras aa §

Spatangidae—

nal aS terbemants (ke OCKICM) teen eames eee ee ate tenes els ee eee lose Ree banal Momdaaesod

Mnallastenobuquatus| Clarks cise eens nee ane ee coe eee nee ne eee ene eee ee eee | eee
Hemiaster elegans'Shumard 2722-222 oto
(emiastersmmbitel Clarke sme eee eee erento ae cio meene e cere ee eae gear eee
Hemiaster bexari Clark ...-
Hemiaster comanchei Clark
PemiastendallitClanksseres sees = sess cane bee esseeeeee cee. samse cn ee ese eee meee ealone P
Hemiastencalyainit@ large ee eee ears se ae a eee nee Sia eer aera nie eS ee Pe ee
EMIS LET PALASLALLIS| (MOLLOD) pssst seen eee ee ean seen eee eee eee eee i
Hemiaster stella (Morton) -..-.- ses 2
Hemiaster ungula (Morton) een saceeea OA
FTemiasteritexanlissRoeMm Chasace sone sac me see ae face ese e eee oe eee Nee pee e ale een eee ee
Hemiaster humphreysanus Meek and Hayden .-.--.........-...-.--.---+----+-------|----------|--
iemiastencalionnicis\ Clarkere perp et eee see ee oe ae ee a eee ee eee eee eee ee
emiastenbeccheril Canker erase acces a ee ene ae eee ete ae ee tee eee | pee eee eee ee
(Eemiastemlactmosusis locum eran see er cee meee eeeama encore eer eee nee ee eeee me eee ene
Hemiaster kiimmeli Clark - - - SoHE BARRIS ARS oaesEHOdS “seasons HoGepuneed (oo
Is G@enbirad yal Oral (Clb hdc oo aS ae Some ace Se Sas BS BbO sp aES Be neOre aa aac omerecbonsel ba deuraeaal ie
Mainithia tumidila Clarke eee sesre o- cee ce seen e ec cean see cee enue ree ee ceee me ene aoe Tae
Linthia variabilis Slocum :

KX

x “

KRKKXK

KKKKKKK KKK KK KK KKK

x XXXxXXxX

KX KXKKKKK KKK KK XK

2

39800°—15

14 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Stratigraphic distribution of the Cretaceous Echinodermata of Texas.

Trinity. Bredericks: Washita. | Austin. Taylor.
Z.
Ophioglypha texana, Clark............---.--- Sosopnee csosees cosessscocesesessonDelpseonossoscellossonccancce x
Cidaris texanus Clark........... Alls Be x ears
Cidaris dixiensis Cragin. .........- Selloctoonoeaace B
Leiocidaris hemigranosus (Shumarc Beal peooesad sa
Salenia texana Credner.........-.- ee

Hypodiadema elegans Clark.....
Goniopygus zitteli Clark_..-....-...--.---.---.----- Bees seea ss
Weptanbacia argitus| Clarkes eee sent neces cen eerenen see eee eee
Orthopsis;planulatal Clarkes ne =e eeee ee nea e eee eee eee eeea eee
Orthopsisioccidentalis\Craginee ee eee eee eee eee
Pseudodiadema texanum (Roemer) .- EVRA SS ESC TES a | SIS a etl | fear) aa
Heterodiadema ornatum Clark
Cottaldia rotula Clark... --.-
Hemipedina charltoni Cragin.
Diplopodia taffi Cragin... .--
Dinlopodiatsteeruvatzi Cragin jae shee ee eee eee en ene means
Cy posma Hill Char ee eee ee ee emia celete see see cictese se eeeteete
CyphosomajvolanumlC@rapinee pee eee eee ee eeee eee eee eee ene
hcropsisilinea tus Clarkes ee pene ne pe eee ee eee eee neers
Pedinopsis/symmetrica/(Cragim))))o 2 eee ee
Pedinopsis pondi Clark......-
Holectypus planatus Roemer
Pyrina parri Hall..-.........-
Echinobrissus augustatus Clar
Echinobrissus texanus Clark. .
iAmanchy;tesitexanal Cragine es sesame er sears Bos
Holastersimplexiohumardses eee shee eee ee eee ee nee eee ae eee
Hnallastentexanus| GRosmen) see ee eeeeeee eee ee eee eee ae eae Rola eee
nallastenobliquatis|Clanke- pepe peer eee eee eee ee Eee eter eee eee
iHemissterielesans| Shumandenee serene er ertee ete nee eee ee eee eee
Hemiaster whitei Clark. ....
Hemiaster bexari Clark. -
Hemiaster comanchei Clar:
Hemiaster dalli Clark ....
Hemiaster cavini Clark... -.

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INTRODUCTION. 15

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16 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

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INTRODUCTION. 17

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18 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.
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Wuirte, ©. A., Contributions to the paleontology of Brazil; eornypiictias descriptions of Cretaceous fayoniclbeane fossils
mainly from the Provinces of Sergipe, Pernambuco, Para, and Bahia: Museo nac. Rio de Janeiro Archivos, vol. 7,
pp. 1-273, Pls. I-X XVII, 1888.

1890.

Corrrau, M., Note sur quelques échinides du terrain crétacé du Mexique: Soc. géol. France Bull., 3d ser., vol. 18,
pp. 292-299, Pls. I, IT, 1890.
1891.

Crark, W. B., A revision of the Cretaceous Echinoidea of North America: Johns Hopkins Univ. Circ., vol. 10,
No. 87, pp. 75-77, 1891.

Dunoan, P. M., Revision of genera and great groups of the Echinoidea: Linn. Soc. Jour., Zoology, vol. 23, pp. 1-
311, 1891.

DumMBiz, EF. T., Notes on the geology of the valley of the middle Rio Grande: Geol. Soc. suunoriie Bull., vol. 3, pp. 319-
330, 1892.

Grecory, J. W., The relations of the American and European echinoid faunas: Geol. Soc. America Bull., vol. 3, pp.
101-108, 1892.

1893.

Aqumera, J. G., and OrDONEz, Ezequiet, Datos para la geologia de México, 87 pp., 1893.

CrarKk, W. B., The Mesozoic Echinodermata of the United States, a preliminary list: Johns Hopkins Univ. Circ.,
vol. 12, No. 103, pp. 51, 52, 1893.

The Mesozoic Echinodermata of the United States: U.S. Geol. Survey Bull. 97, 207 pp., 50 pls., 1893.

A preliminary report on the Cretaceous and Tertiary Horm of New Jersey, etc.: Geol. Survey New Jersey,
Ann. Rept. for 1892, pp. 167-229, 1893.

Crasein, F. W., A contribution to the invertebrate paleontology of the Texas Cretaceous: Geol. Survey Texas Fourth
Ann. Rept., pp. 189-294, Pls. XXIV—XLVI, 1893.

Hut, R. T., Paleontology of the Cretaceous formations of Texas; The invertebrate paleontology of the Trinity divi-
sion: Biol. Soc. Washington Proc., vol. 8, pp. 9-40, Pls. I-VIII, 1893.

Wuuston, S. W., The Niobrara ireiaecons of western Kansas: Kansas Acad. Bel. Trans., vol. 13, pp. 107-111, 2
pls., 1893.

1894.

Batuer, F. A., Echinoderma: Zool. Record for 1893, pp. 1-107, 1894.

Cracin, F. W., The Choctaw and Grayson terranes of the Arietina: Colorado Coll. Studies, vol. 5, pp. 40-48, 1894.

Descriptions of invertebrate fossils from the Comanche series in Texas, Kansas, and Indian Territory: Colorado
Coll. Studies, vol. 5, pp: 49-68, 1894.

Smrru, J. P., Age of the auriferous slates of the Sierra Nevada: Geol. Soc. America Bull., vol. 5, pp. 243-258.

Wituston, 8. W., and Hi, B. H., Notes on Uintacrinus socialis Grinnell: Kansas Univ. Quart., vol. 3, pp. 19-21 and
diagram, 1894.

1895.

Baruer, F. A., Echinoderma: Zool. Record for 1894, pp. 1-55, 1895.

Crain, F. W., A new Cretaceous genus of Clypeastride: Am. Geologist, vol. 15, pp. 90, 91, 1895.

Dume.e, EB. T., The Cretaceous of western Texas and Coahuila, Mexico: Geol. Soc. America Bull., vol. 6, pp. 375-
388, 1895.

1896.

Baruer, F. A., Echinoderma: Zool. Record for 1895, vol. 32, pp. 1-70, 1896.
Uintacrinus; a morphological study: Zool. Soc. London Proc. for 1895, pp. 974-1004, Pls. LIV—LVI, 1896.

1897.

Acutpra, J. G., Sinopsis de geologia mexicana: Inst. geol. México Bol. 4, 5, and 6, pp. 187-250, 1897.

Cuark, W. B., Upper Cretaceous formations of New Jersey, Delaware, and Maryland: Geol. Soc. America Bull., vol. 8,
pp. 315-318, Pls. XL-L, 1897.

Wuurston, 8. W., The Kansas Niobrara Cretaceous: Kansas Univ. Geol. Survey, vol. 2, pp. 242, 243, 1897.

INTRODUCTION. 19

1898.

BarueEr, F. A., Echinoderma: Zool. Record for 1897, vol. 34, pp. 1-135, 1898.

Crark, W. B., Report upon the Upper Cretaceous formations: New Jersey Geol. Survey Ann. Rept. for 1897, pp. 161-
210, 1898.

Hut, R. T., and Vauenan, T. W., Geology of the Edwards Plateau and Rio Grande plain adjacent to Austin and San
Antonio, Tex. with reference to the occurrence of underground waters: U. 8. Geol. Survey Eighteenth Ann.
Rept., pt. 2, pp. 193-321, Pls. XXI-LXIV, 24 figs., 1898.

Loaan, W. N., The invertebrates of the Benton, Niobrara, and Fort Pierre groups: Kansas Univ. Geol. Survey, vol. 4,
pt. 1, pp. 431-518, 1898.

Weep, W. H., and Prrsson, L. V., Geology and mineral resources of the Judith Mountains of Montana: U. S. Ceol
Survey Bighteenth Ann. Rept., pt. 3, pp. 437-616, Pls. LIX-LXXXVII, 25 figs., 1898.

1899.

Barner, F. A., Echinoderma: Zool. Record for 1898, vol. 35, pp. 1-73, 1899.

Bost, Emo, Geologia de los alrededores de Orizaba: Inst. geol. México Bol. 13, pp. 1-52, 1899.

Darton, N. H., Jurassic formations of the Black Hills, 8. Dak.: Geol. Soc. America Bull., vol. 10, pp. 383-396,
Pls. XLII-XLIV, 1899.

SPRINGER, FRANK, Notice of a new discovery concerning Uintacrinus: Am. Geologist, vol. 24, p. 92, 1899.

Sranton, T. W., Mesozoic fossils of the Yellowstone National Park: U.S. Geol. Survey Mon. 32, pt. 2, pp. 600-

640, 1899.
1900.

Baruer, F. A., Echinoderma: Zool. Record for 1899, vol. 36, pp. 1-101, 1900.

A treatise on zoology, pt. 3, The Echinodermata, 1900.

Berecuer, C. E., Ona large slab of Uintacrinus from Kansas: Am. Jour. Sci., 4th ser., vol. 9, pp. 267-268, Pls. III, IV,
1900.

Hoimes, J. A., The deep well at Wilmington, N. C.: Science, new ser., vol. 11, pp. 128-130, 1900.

Kniceut, W. C., A preliminary report on the artesian basins of Wyoming: Wyoming Exper. Sta. Bull. 45, pp. 105-251,
Pls. I-XIV, 1900.

Jurassic rocks of southeastern Wyoming: Geol. Soc. America Bull., vol. 11, pp. 377-388, Pl. XXIII, 1900.

Loaan, W. N., The stratigraphy and invertebrate faunas of the Jurassic formation in the Freezeout Hills of Wyoming:
Kansas Univ. Quart., vol. 9, pp. 109-134, Pls. XX V—XXXI, 1900.

Sprincer, F., Uintacrinus; its structure and relations: Mus. Comp. Zool. Mem., vol. 25, No. 1, 90 pp., 8 pls., 3 figs., 1900.

VaucuHan, T. W., Reconnaissance in the Rio Grande coal fields of Texas: U.S. Geol. Survey Bull. 164, 100 pp., 11 pls.,
1900.

ViarEAt, F., Paleontologia sudamericana; Echinodermata: Revist. cienc. Lima, vol. 3, pp. 129-132, 1900.

1901.

Baruer, F. A., Echinoderma: Zool. Record for 1900, pp. 1-153, 1901.

Darton, N. H., Preliminary description of the geology and water resources of the southern half of the Black Hills and
adjacent regions in South Dakota and Wyoming: U.S. Geol. Survey Twenty-first Ann. Rept., pt. 4, pp. 489-599,
Pls. LVIII-CXII, 28 figs., 1901.

Hut, R. T., Geography and geology of the Black and Grand prairies, Texas, with detailed descriptions of the Creta-
ceous formations and special reference to artesian waters: U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, pp-

. 86-386, Pls. XIV-LIV, 56 figs., 1901.
LrypGren, W., Trias in northeastern Oregon: Science, new ser., vol. 13, pp. 270, 271, 1901.

1902.

Bartuer, F. A., Echinoderma: Zool. Record for 1901, vol. 38, pp. 1-99, 1902.

Anperson, F. M., Cretaceous deposits of the Pacific coast: California Acad. Proc., 3d ser., Geology, vol. 2, No. 1, 154
pp., 12 pls., 1902.

H[ovey], E. O., A remarkable slab of fossil crinoids: Am. Mus. Nat. Hist. Jour., vol. 2, pp. 11-14, 1 pl., 1 fig., 1902.

1903.

Bartuer, F. A., Echinoderma: Zool. Record for 1902, vol. 39, pp. 1-88, 1903.

Dove ass, E., Astropecten (?) montanus—a new starfish from Fort Benton—and some geological notes: Carnegie Mus.
Pub. 20, Carnegie Mus. Ann., vol. 2, pp. 5-8, 1 fig., 1903.

Warrraves, J. L., On some additional fossils from the Vancouver Cretaceous, with a revised list of the species there
found; Mesozoic fossils: Geol. Survey Canada, vol. 1, pt. 5, pp. 309-415, Pls. XL-LI, 1903.

1904.

Batuer, F. A., Echinoderma: Zool. Record for 1903, vol. 40, pp. 1-105, 1904.

WHITEAVES, J. F. , Uintacrinus and Hemiaster in the Vancouver Cretaceous: Am. Jour. Sci., 4th ser., vol. 18, pp. 287-
289, 1904.

ScuucHert, CHARLES, A noteworthy crinoid: Smithsonian Misc. Coll., vol. 45, p. 450, Pl. CIITI, 1904.

20 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

\

1905.

Baruer, F. A., Echinoderma: Zool. Record for 1904, vol. 41, pp. 1-96, 1905.

Craain, F. W., Paleontology of the Malone Jurassic formation of Texas: U. 8. Geol. Survey Bull. 266, 172 pp., 29 pls.,
1905.

Jounson, C. W., Annotated list of the types of invertebrate Cretaceous fossils in the collection of the Academy of Natural
Sciences, Philadelphia: Acad. Nat. Sci. Philadelphia Proc., vol. 57, pp. 4-28, 1905.

WELLER, Stuart, A fossil starfish from the Cretaceous of Wyoming: Jour. Geology, vol. 13, pp. 257, 258, fig. 1, 1905.

1906.
Grant, M., Echinoderma: Zool. Record for 1905, pp. 1-92, 1906.
1907.

WELLER, Stuart, A report on the Cretaceous paleontology of New Jersey; Echinodermata: Geol. Survey New Jersey,
pp. 275-305, Pls. VI-X VIII, 1907.
1909.

Basster, R. §., Some noteworthy accessions to the division of invertebrate paleontology in the National Museum:
Smithsonian Misc. Coll., vol. 52, pp. 267-269, Pls. XVII, XVIII, 1909.

Lampert, J., and Turiry, P., Essai de nomenclature raisonnée des échinides, 1909.

Stocum, A. W., New echinoids from the Ripley group of Mississippi: Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4,
No. 1, pp. 1-16, Pls. I-III, 1909.

Springer, Franx, A new American Jurassic crinoid: U. 8. Nat. Mus. Proc., vol. 36, pp. 179-190, Pl. IV, 1909.

1910.

Crark, W. B., and TwrrcHett, M. W., Geological distribution of the Mesozoic and Cenozoic Echinodermata of the
United States: Geol. Soc. America Bull., vol. 20, 1908, pp. 686-688, 1910.

1911.

Sprincsr, Frank, Some new American crinoids: Mus. Comp. Zool. Mem., vol. 25, No. 3, pp. 117-161, Pls. I-VI,
MOE

Norz.—A number of contributions have appeared during the progress of this report through the press, the results
of which can not be fully incorporated in the following pages, although footnotes concerning some of them have been
inserted. Among the more important of these publications are:

Jackson, R. T., Phylogeny of the Echini, with a revision of Paleozcic species: Boston Soc. Nat. Hist. Mem., vol. 7,
491 pp., 76 pls., 258 figs., 1912. :
Jackson proposes the generic name Centrechinus to replace Diadema, thus changing the names of family and
order to which the genus belongs.
Surru, J. P., The Middle Triassic marine invertebrate faunas of North America: U. 8. Geol. Survey Prof. Paper 83,
254 pp., 99 pls., 1914.
Smith refers to Pentacrinus cf. P. asteriscus Meek and Hayden, in material from the Pit shale of California.

TRIASSIC ECHINODERMATA.
Class CRINOIDEA.
Subclass DICYCLICA.

Order INADUNATA.
Suborder DENDROCRINOIDEA.
Family PENTACRINIDA.

Genus ISOCRINUS von Meyer.
IsocRINUS SMITHI Clark, n. sp.
Plate I, figures la-b.

Determinative characters.—Column composed of small moderately thick pentagonal joints,
with sharp reentering angles on the large specimens. Column perforated by small canal.

Dimensions.—Column: Diameter of jomt 4 to 2 millimeters; length of joint 4 to 1 milli-
meter.

Description.—The joints are generally separated and more or less weathered, being found
in great numbers on many leached surfaces of limestone. The largest and best-preserved speci-
mens are moderately thick and show sharp reentering angles. The crenulated ridges are gen-
erally so badly weathered that their characters are obscured, but they are broadly petaloid
with rather sharp angles at their outer extremities. All the Lower Triassic forms are assigned
to this species. Some minor differences appear among the specimens examined, however, and
more than one species may be represented.

Locality —One mile west of Paris, Bear Lake County, Idaho. \

Geologic horizon.—Columbites zone, Thaynes limestone, Lower Triassic, 150 feet above
strata with Meekoceras fauna, but below beds containing typical Lower Triassic forms.

Collections.—U. S. National Museum (31184); Leland Stanford Junior University.

IsocrINUsS CALIFoRNIcUS Clark, n. sp.
Plate I, figures 2a-c

Determinative characters.—Column composed of medium-sized rather thin pentagonal joints,
with sharp reentering angles. The crenulated ridges are rather narrowly petaloid, and each
area is sharply terminated at its outer extremity. Column perforated by large canal.

Dimensions.—Column: Diameter of joint 2 to 5 millimeters; length of joimt 4 to 1 milli-
meter.

Description.—Several specimens of isolated column joints of Isocrinus from the Upper Trias-
sic rocks of California, which may or may not belong to a single species, have been examined by
the author. Differences in the size of the joints and the sharpness of the reentering angles
appear, but they may be due to difference in age of the individuals represented or by the differ-
ent positions of the jomtson the stem. In the absence of more satisfactory criteria, therefore, all
the Upper Triassic Pentacrini examined have been referred to this species. The majority of
specimens studied are not of large size, although considerably larger than J. smithi of the Lower
Triassic. Most of them show deep reentering angles. The crenulated ridges are obscure in
many specimens, but where well preserved are rather narrowly petaloid, and each area is sharply
terminated at its outer extremity. A large well-marked canal perforates the column.

21

bo
bo

MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Locality.—Two and one-half miles west of Round Mountain, Shasta County (type), and at
Rush Creek, Plumas County, Cal.

Geologic horizon.—‘‘ Cedar formation,” Upper Triassic.

Collections.—U. S. National Museum (31185); Leland Stanford Junior University.

TsocRINUS sp.

Pentacrinus asteriscus (?) Hall and Whitfield, 1877, U. S. Geol. Expl. 40th Par. Final Rept. vol. 4, pp. 280, 281, Pl. VI,
fig. 16.

Hall and Whitfield examined several column joints of supposed Pentacrinus collected by
Arnold Hague of the 40th Parallel Survey “‘in limestone of supposed Triassic age, associated
with Spiriferina homfrayi and Terebratula humboldtensis Gabb, near Dun Glen Pass, Pahute
Range, Nevada,” which they doubtfully referred to P. asteriscus Meek and Hayden of the Juras-
sic of the Rocky Mountain region. They note certain differences ‘‘in the more obtuse points of
the star, and the filling up of the angles between the points, and also in the broader form of the
elliptical figures on the articulating surfaces of the disks.” They state that although these fea-
tures are not constant the form is larger than P. asteriscus, and that better material would doubt-
less show it to be another species. It is evident that this form can not be safely referred to the
Jurassic species P. asteriscus, but as the author has not had access to further material it is simply
referred to the genus Isocrinus without specific description. The limestones at Dun Glen Pass
were correlated with the base of the Star Peak formation, and more recent work has confirmed
this determination. The Star Peak formation is of both Middle and Upper Triassic age.

Locality Dun Glen Pass, Pahute Range, Nevada.

Geologic horizon.—Limestone of Dun Glen Pass, Middle Triassic.

Collection.—U. 5. National Museum.

Family ENCRINID®.
Genus ENCRINUS C. F. Schulze.
Enerinus Hyatti Clark, n. sp.

Plate I, figures 3a-b.

Determinative characters.—Column composed of large, thin, round to oval joints. Surfaces
of joints covered with fine, bifurcating striations, producing a close suture. Column perforated
with canal of rather small size.

Dimensions.—Column: Diameter of joint 5 to 10 millimeters; length of joint 1 to 3 milli-

meters. :
Description.—Several specimens of casts of the column joints of Encrinus have been exam-

ined by the author from a single Upper Triassic locality in California. The column itself is
wanting in every specimen, but the cast of the ‘‘close surface” is very perfect, much more so than
the cast of the outer surface, which in all specimens has lost its distinctive features. Most of the
casts show a somewhat oval outline, which may be due to compression, as the stems of most of
the species belonging to this genus are round.

The joints surpass considerably in size those of any other crinoid form in the American
Mesozoic. The round to oval shape of the “close surface”’ of the specimens and the fine bifur-
cating striations thereon are highly distinctive, enabling the relations of the form to be readily
determined even in small fragments. All the specimens evidently belong to the same species.
A rather small canal is present.

Locality.—Oscar tunnel, 24 miles southeast of Longville, Plumas County, Cal.

Geologic horizon.— Cedar formation,’ Upper Triassic.

Collection.—U. S. National Museum (31186).

1 During the progress of this report through the press a paper by J. P. Smith (The Middle Triassic marine invertebrate faunas of North
America: U.S. Geol. Suryey Prof. Paper 83, 1914) has appeared, in which he says (p. 148): ‘‘A species identical with that of Dun Glen, Ney.,
occurs in the Pit shale of California, associated with a poor fauna characteristic of the Middle Triassic.’’ It is referred to Pentacrinus cf.
P. asteriscus Meek and Hayden,

TRIASSIC ECHINODERMATA, 23
Class STELLEROIDEA.
Subclass OPHIUROIDEA.
Order ZYGOPHIURZ.

Family AMPHIURID.
Genus ASPIDURA Agassiz.
AspipuRA (?%) mAHOENSIS Clark, n. sp.
Plate I, figure 4.

Determinative characters —Casts of small forms, with short arms. Very poorly preserved.

Dimensions.—Diameter of disk 5 to 7 millimeters; length of arms 10 to 25 millimeters.

Description.—Three individuals of this species, all in a very imperfect state of preservation,
have been examined. They occur as partial casts of the disk and rays. The characteristics of
none of the plates can beseen. The general outline of the disk and rays remains constant in all
the specimens, which evidently belong to the same species.

Locality—One and one-half miles west of Paris, in the first canyon north of Paris Canyon,
Bear County, Idaho.

Geologic horizon.—Thaynes limestone, Lower Triassic.

Collection —U. 8S. National Museum (31187).

Class ECHINOIDEA.
Subclass REGULARIA ENDOBRANCHIATA.
Order CIDAROIDEA.
Family CIDARID.
Genus CIDARIS Leske.
CipaRIs SHASTENSIS Clark, n. sp.

Plate I, figure 5.

Determinative characters—Test apparently large. Interambulacral areas wide. Tubercles
large, circular, with depressed areolas; miliary space large.

Dimensions—Width of fragment 10 millimeters; height of fragment 6 millimeters.

Description.—The single fragmentary interambulacral plate found indicates that this species
possessed a test of considerable size. The interambulacral areas are wide, the tubercles large,
circular, and with depressed areolas. The miliary space is large. The plate is probably from
near the ambitus. The broken tubercle renders it impossible to say whether the mamelon was
perforated or not. There is no trace of the plates of the ambulacral area. Z

Related forms.—Species is shown by the wide miliary space to be quite distinct from C. dil-
teri. It is evidently a new species.

Locality.—Two and one-half miles west of Round Mountain, Shasta County, Cal.

Geologic horizon—‘‘ Cedar formation,” Upper Triassic.

Collection. —U.S. National Museum (31188).

CimpaRts DILLERI Clark, n. sp.
Plate I, figure 6.

Determinative characters.—Test apparently of medium size; ambulacral areas narrow, flexu-
ous, with two rows of granules between the poriferous avenues; interambulacral areas of mod-
erate width. Tubercles of medium size with oval areolas; boss crenulated; mamelon perforated;
miliary space narrow.

24 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions.—Test: probable diameter about 35 millimeters; probable height about 25 milli-
meters: size of interambulacral plate near ambitus: Width 8 millimeters; height 6 millimeters.

Description.—The portion of the test studied in the single specimen of this species thus far
found is in the form of a cast of the exterior of three interambulacral plates with their adjacent
ambulacral plates on either side. The casts afford a very perfect mold of the more important
features of these plates, which are apparently below the ambitus, in this respect differing from
the specimen of C. shastensis, which comes apparently from nearer the ambitus.

The test was probably of medium size. The ambulacral areas are narrow, strongly flexuous,
with two rows of small granules between the poriferous avenues. The interambulacral areas are
of moderate width, being largely occupied by the tubercles, which are of medium size. The
areolas are oval, the boss crenulated and the mamelon perforated. The miliary space is very
narrow, very few granules being found on the area.

Related forms.—Form is shown by its small miliary areas to be quite distinct from C.
shastensis. It is evidently a distinct species.

Locality.—Two and a half miles west of Round Mountain, Shasta County, Cal.

Geologic horizon.—‘‘Cedar formation,” Upper Triassic.

Collection —U. S. National Museum (31189).

JURASSIC ECHINODERMATA.
Class CRINOIDEA.
Subclass DICYCLICA.
Order INADUNATA.
‘Suborder DENDROCRINOIDEA.
Family PENTACRINID 2.
Genus ISOCRINUS von Meyer.
IsocrInUs KNIGHTI Springer.
Plate II, figures 1-13; Plate III, figures la-d.
? Pentacrinites asteriscus Meek and Hayden, 1865, Paleontology Upper Missouri: Smithsonian Contr., vol. 14 (172),
p. 67, text fig. (not PI. III, figs. 2a-b).
Pentacrinus asteriscus Knight, 1900, Geol. Soc. America Bull., vol. 11, p. 386.

? Pentacrinus asteriscus Logan, 1900, Kansas Univ. Quart., vol. 9, p. 119, Pl. XXV, fi
Isocrinus knighti Springer, 1909, U. S. Nat. Mus. Proc., vol. 36, pp. 179-190, Pl. IV,

Ss. 4-7.
gs. 1-13.

g
fi

Determinative characters.—Springer describes the species as follows:

Specimens of moderate size.

Stem smooth, long, slightly increasing in diameter distally; pentagonal with straight sides, except at the proximal
end, where for the first few immature internodes the younger joints are stellate. Internodals about 14, but varying
from 12 to 17 in the mature parts; distinctly crenulated at the margins; nodals not enlarged, scarcely distinguishable
from the others except by the cirrus sockets; these are rather shallow, not extending to the hypozygal, or infranodal
joint, but usually encroaching upon the supranodal, in which case the apposed faces of these two joints are more or less
indented, producing a marked stellate outline. Conformably to this structure the cirri are directed upward. Inter-
articular pores extending to the fifth internode. Cirri in whorls of five; round, long, and slender, composed of 40
joints or more; the proximal ones relatively short and broad—about one-third as long as wide—tapering rapidly to
about half their breadth, and doubling in length in the first 8 or 10 joints, beyond which they continue uniformly about
as long as wide to the end; terminal claw not preserved. Angles of stem interradial; cirri radial; axial canal in stem
small, obtusely pentagonal, and apparently interradial in position.

Cup forming a low cone, without any downward projection or basals or radials. Infrabasals well defined, filling
half the diameter of the column facet and entirely covered by the proximal columnal. Basals large, smooth, visible
in pentagonal outline, and in full contact exteriorly by their lateral faces; they form a closed ring, not protuberant
but flush with the plane of the radials, and about equal to them in height. RRadials forming also a ring continuous with
basals. Primibrachs two, united by articulation apparently bifascial. Arms simple, or bifurcating once from the
sixteenth to the thirtieth I1Br, thus varying from 10 to 20; they are long, slender, with strongly oblique articulating
faces, and they extend to upward of 90 brachials. Syzygies at I1Br 3 + 4, and beyond throughout the arm at intervals
of about 5 to 10 brachials. Pinnules long, rounded, composed of elongate joints, 15 or more in the distal pinnules,
but the number in the proximal ones not observable. Disk unknown.

Dimensions.—Height of crown 65 millimeters; length of cirrus of 40 joints 32 millimeters;
length of longest stem preserved 140 millimeters; diameter of stem at second internede 2 milli-
meters; diameter of stem at tenth internode 2.5 millimeters.

Description.—The first complete crown of this species was obtained by the late W. C. Knight,
of the University of Wyoming, in 1899, in the course of his investigations of the Morrison forma-
tion near Medicine Bow, Wyo. He found one very complete specimen and numerous stems and
fragments of arms on several small slabs of argillaceous limestone that lay in the débris. He
referred the crown to Pentacrinus asteriscus. Some additional material obtained the following
year has afforded several additional crowns. All the specimens were finally placed for study
in the hands of Springer, who finds reasons for believing that the form belongs to Isocrinus and
not Pentacrinus. *

1 A new American Jurassic crinoid: U. S. Nat. Mus. Proc., vol. 36, pp. 179-190, Pl. IV, 1909.

26 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Springer in describing this species makes the following interesting comparison with recent
species:

The stem has a considerable resemblance to that of I. decoruws, except in the disposition of the cirri. It must have
been quite long, as the longest portion, preserved to a distance of 140 millimeters, shows little sign of any rounding. It
is rather more pentagonal for equivalent distances. The cirri are very long and slender; the taper near the base from
short and wide joints to long, narrow, and equal ones is quite marked. The most perfect one has 44 joints, and this
was probably near the maximum. The interesting thing about the cirri, however, is the fact that they are directed
upward instead of downward or outward. In consequence the sockets do not extend to the infranodal (hypozygal)
joint, but slope upward toward the supranodal, the lower margin of which is often incised by them. This is more or
less the case in the genus Metacrinus, but is not usual in the recent species of Isocrinus, most of which have the cirri
directed downward, though in some, as J. asteria and I. wyville-thomsoni, the socket is confined to the nodal joint, and
the cirri are given off about horizontally.

The basals, as shown by the five specimens figured and three others, are quite uniform in their form and propor-
tions. They form with the radials a low funnel, with smooth or slightly rounded sides, and without protuberance or
projection of any kind. They are connected exteriorly by their lateral faces, giving a pentagonal outline and forming
a closed ring [ PI. II, fig. 3a], as in the type for which Forbes proposed the genus Cainocrinus, instead of appearing as
mere triangular points separated from each other by the radials and tending more or less to project downward over the
proximal column joints, as in more recent species.

The bifurcation of the arms so far beyond the axillary [Br is an unusual feature, occurring in the largest specimen
at the twenty-seventh to the thirtieth brachial [P1.II, fig. 1], and in other specimens from the sixteenth to the twenty-
third. I know of no pentacrinoid in which arm division takes place so high up; nor in fact any inadunate crinoid, the
nearest approach to it being found in the Carboniferous genus Poteriocrinus. There is little tendency of the arms to
spread out, but they are long and slender, tending rather to lie in a bundle. The general aspect of calyx and arms is
somewhat like that of J. naresianus, which it also resembles in the number and regularity of the syzygies, which is
unusual in the Pentacrinide. I can trace them in two arms of specimen A [Pl. II, fig. 1] part way, and in one to the
end, and can distinguish them in the distal portion of some other arms. Beginning at I1Br 3 + 4, they occur at inter-
vals of mostly about 10 brachials, but sometimes 4,5 or 6. I give a figure of the pair next to the last, being about
brachials 79 + 80 of that arm [PI. IT, fig. la].

Related forms.—Springer states that the stem joints of I. knightt —

are uniformly different from the much larger.ones on which P. asteriscus was founded, and from the Utah specimen
referred by Dr. White to P. asteriscus ! but afterwards separated from it by Dr. W. B. Clark under the name Penta-
crinus whitei, because of its alternating joints. Clark’s camparison was made chiefly with the Red Buttes specimen of
P. asteriscus (?), but the separation is doubtless well founded, nevertheless, as the character on which he bases it is
clear in his specimen, and cannot be shown in the type of P. asteriscus. The difference between the stem of our species
and that of P. whitet is similar to that between the recent J. decorus and J. parrz, which is fairly constant.

The most nearly related European species that I know of is de Loriol’s “‘ Pentacrinus’’ beaugrandi from the Upper
Jurassic, Portlandian stage, near Boulogne-sur-Mer, France.? This was the only Crinoid known to the author from
the Portlandian stage, and it is the species which he originally proposed to separate from the other Pentacrinidz on
account of having a closed ring of basals, under the name Picteticrinus. In this he found himself anticipated by the
Cainocrinus of Forbes, ‘and in the work last cited, page 281, he abandoned the distinction, and referred the species to
Pentacrinus (sensu P. H. C. ). It has similar large basals, but the arms branch lower down, the stem is more sharply
stellate in corresponding portions, and the cirri much more delicate. The stem is preserved to the fourth internode,
which has 8 internodals, whereas ours has 14 at the same stage. :

Pentacrinus (Cainocrinus) andree Desor * is similar to the French species, but with shorter basals and shorter
internodes.

Localities. —Medicine Bow (type) and Red Buttes, Wyo.
Geologic horizon.—Sundance formation (Shirley stage of Knight), Upper Jurassic.
Collection.—U. S. National Museum (682).

Genus PENTACRINUS Blumenbach.
PENTACRINUS ASTERISCUS Meek and Hayden.

; Plate III, figure 2.
Pentacrinus asteriscus Meek and Hayden, 1858, Acad. Nat. Sci. Philadelphia Proc., vol. 10, p. 49.
Pentacrinus asteriscus Meek and Hayden, 1860, Acad. Nat. Sci. Philadelphia Proc., vol. 12, p. 419.
Pentacrinus asteriscus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 27.
Pentacrinites asteriscus Meek and Hayden, 1865, Paleontology Upper Missouri, Smithsonian Contr., vol. 14 (172), p. 67,
Pl. III, figs. 2a, 2b.

1U.S. Geol. Survey Bull. 97, p. 27, 1893.

2 Mon. étage Jur. Boulogne-sur-Mer, p. 298, Pl. XXVI, figs. 23-25, 1875; Paléontologie francaise, Crinoides, yol. 11, pt. 2, p. 278, Pl. CLXXXT,
figs. 1-3.

3 De Loriol, Crin. foss. de la Suisse, p. 112.

JURASSIC ECHINODERMATA, 27

Pentacrinites asteriscus Whitfield, 1880, Paleontology of Black Hills of Dakota: U. S. Geog. and Geol. Survey Rocky

Mtn. Region, p. 345, Pl. III, figs. 1, 2.

Pentacrinus asteriscus Peale, 1880, U. S. Geol. and Geog. Survey Terr. Bull., vol. 5, No. 1, p. 120.
Pentacrinus asteriscus Clark, 1893, Johns Hopkins Uniy. Cire., vol. 12, No. 103, p. 51.

Pentacrinus asteriscus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 26, 27, Pl. II, figs. 2a-d.
Pentacrinus asteriscus Weed and Pirsson, 1898, U. S. Geol. Survey Eighteenth Ann. Rept., pt. 3, p. 478.
Pentacrinus asteriscus Stanton, 1899, U.S. Geol. Survey Mon., vol. 32, pt. 2, p. 608.

Pentacrinus asteriscus Knight, 1900, Wyoming Exper. Sta. Bull. 45, Pl. IV, fig. 2.

Pentacrinus asteriscus Darton, 1901, U. S. Geol. Survey Twenty-first Ann. Rept., pt. 4, p. 521.

Determinative characters—Columns composed of medium-sized pentagonal joints with
moderately deep reentering angles; crenulated ridge of suture strongly petaloidal; column per-
forated by canal of medium size.

Dimensions—Column: Diameter of joint 2 to 5 millimeters.

Deseription.—First described by Meek and Hayden from several column joints found in the
Black Hills. When they redescribed and figured the species in 1865 they combined with the
earlier forms certain smaller column joints found at Red Buttes on North Platte River, figures
of which were given in the text, but these have been recently doubtfully referred by Springer to
Isocrinus knighti. Meek and Hayden in this later publication state that their ‘‘description
apples more particularly to the largest-sized specimens”’ from the Black Hills and that the two
figures on their Plate III represent these forms, which must therefore be regarded as the type
of the species.

Many similar isolated column joints have been found widely scattered throughout the
Rocky Mountain region by different geologists and most of them are regarded by the author as
belonging to this species. Since it has been clearly demonstrated that the column joints vary
in the different portions of the stem of nearly all crinoids it is evident that several different
species and possibly even different genera may be represented among these forms.

The specimens referred to this species are of moderate size, clearly pentagonal, and with
moderately deep reentering angles, the points of the rays being sharp, and the suture joints
apparently uniting to form a compact column.

Hall and Whitfield referred doubtfully to Pentacrinites asteriscus Meek and Hayden certain
specimens collected by Hayden in Nevada from “limestones of supposed Triassic age.” There
is much doubt as to this form, but it evidently does not belong to P. asteriscus.

Related forms.—The species presents some points of difference from P. whitei, which has
been generally regarded as belonging to it. Its column joints are generally somewhat smaller,
are not alternating, do not have as deep reentering angles, and its rays are somewhat sharper.
The crenulation of its petaloid area is also somewhat different. This species is somewhat similar
to Pentacrinus shastensis of the Pacific coast, but the latter is of slightly different form and gen-
erally has shallower reentering angles.

Localities —South and southwest base of Black Hills, South Dakota (type), and Red Buttes,
Wyo.; South Dakota, Idaho, and Colorado (Meek); southeastern Idaho and western Wyoming
(Peale); Black Hills, South Dakota (Whitfield); Sundance formation (Upper Jurassic), Black
Hills, South Dakota (Darton).

Geologic horizon.—Jurassic.

Collection.—U. S. National Museum (220); University of Kansas.

PENTACRINUS WHITE! Clark.
Plate III, figures 3a-c.

Pentacrinus asteriscus White, 1875, U. S. Geog. Surveys W. 100th Mer. Rept., vol. 4, pt. 1, p. 162, Pl. XIII, figs. 6a—-b.
Pentacrinus whitei Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Pentacrinus whitei Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 27, 28, Pl. IIT, figs. 2a-d.
Pentacrinus whitei Springer, 1909, U.S. Nat. Mus. Proc., vol. 36, p. 188.

Determinative characters—Column composed of large, thin, alternating, pentagonal joints
with deep reentering angles; crenulated ridges of suture with strong pentaloid arrangement;
column perforated by canal of medium size.

28 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions —Column: Diameter of joint 5 to 8 millimeters; height of joint 1 to 1}
millimeters.

Description.—C. A. White describes and figures certain specimens as Pentacrinus asteriscus
Meek and Hayden that evidently belong to a different species. Springer, who has examined the
same material, is likewise of the opinion that the separation of the forms from P. asteriscus is
well founded. The name P. whitei was proposed by the author in honor of the distinguished
geologist who did so much to advance our knowledge of western American Mesozoic geology and

aeligontiolosy,

The column joints are relatively thin, with rounded edges, and alternate with each other, so
that the column does not appear aounypawily formed when semred from the side. A distinct
petaloid arrangement of the crenulated ridge is exhibited in all the forms.

Related forms.—The species is apparently closely related to P. asteriscus, from which it is
separated by its generally larger alternating joints, deeper reentering angles, and less compact
column.

Localities. Salt Creek (type) and Diamond Valley, Utah (White).

Geologic horizon.—Jurassic.

Collection.—U. S. National Museum (8588).

PENTACRINUS SHASTENSIS Clark, n. sp.
Plate III, figure 4.

Determinative characters —Column composed of rather large pentagonal joints, with promi-
nent reentering angles. The crenulated ridges of the suture have a rounded petaloid arrange-
ment. Column perforated by a rather large canal.

Dimensions—Column: Diameter of joint 6 to 9 millimeters; thickness of joint 1 to 14 milli-
meters.

Description.—A number of casts of column joints of a Pentacrinus of medium size have been
found in a very compact sandstone. They show very clearly the shape and exterior markings
of the joints, which have very pronounced reentering angles and sharp long rays. In one of the
best preserved specimens the crenulated edges of the suture present a prominent petaloid arrange-
ment. This is not distinguishable in most of the specimens, which are too poorly preserved to
show the finer details. Two of the specimens are casts of several combined joints in which the
side characters of the column are clearly shown. The column is perforated by a rather large
canal.

Related forms.—The species is somewhat similar to P. asteriscus Meek and Hayden, but ts
larger and of somewhat different form.

Localities —One-half mile north of Holeombs stage station, 4 miles north of Buzzards Roost,
and about 24 miles west of Buzzards Roost (type), Shasta County, Cal.

Genta horizon.— Jurassic.

Coliection.—U. S. National Museum (31190).

Class STELLEROIDEA.
Subclass ASTEROIDEA.
Order CRYPTOZONIA.
Family ASTERITID®.
Genus ASTERIAS Linnzus.
ASTERIAS ? DUBIUM Whitfield.

Plate III, figure 6.

Asterias? dubium Whitfield, 1877, Preliminary report on the paleontology of the Black Hills, p. 15.
Asterias? dubium Whitfield, 1880, Paleontology of the Black Hills of Dakota, pp. 344, 345, Pl. III, fig. 3
Asterias dubium Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Asterias? dubium Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 31, 32, Pl. V, fig. 2

Asterias dubium Logan, 1900, Kansas Univ. Quart., vol. 9, pp. 180, 131, Pl. XXV, fig. 4

JURASSIC ECHINODERMATA, 29

Determinatiwe characters.—Imperfectly preserved forms of small size, with slender flexuous
arms, apparently covered superiorly with longitudinal rows of plates.

Dimensions.— Diameter of disk 10 to 12 millimeters; length of arms 15 to 28 millimeters.

Description.—This interesting but doubtful form is thus characterized by Whitfield:

The specimens are not in condition to afford a full description of their specific characters. They are of small size,
the rays being from three-fourths of an inch to 1} inches long, measuring from the center of the body. The rays are
slender and flexuous, most of them being more or less curved in their direction and elevated along the middle, as shown
on a gutta-percha cast taken in a natural mold of a group of three individuals. The upper surface is subangular, and in
structure they are apparently composed of small uniform plates, placed in longitudinal rows. The center of the body
or disk is marked by an obscurely pentangular depression on the upper surface. None of the specimens show the under
side of the body or rays, so that the characters of these parts are entirely unknown.

The species appears to have been somewhat abundant, judging from the condition in which they are grouped on
the sandstone, and, although the specimens are obscure and too imperfect for positive determination and description,
it has been thought best to designate them by names, as they will undoubtedly prove a characteristic form over a cer-
tain region and of a limited horizon. The sandstone is marked by the layers in which they are found by ripple or wave
marks, having a width of about 3 inches, and indicates a near proximity to a shore line over the area where they were
obtained, and that the individuals are probably stranded specimens. A single very imperfect impression of a lamelli-
branchiate shell is seen on the same fragments of rock, but too imperfect for determination.

Related forms.—This doubtful species scarcely admits of comparison with other forms.
There is nothing from American Jurassic strata with which it can be closely associated.

Localities.—Kast side of Spearfish Creek near its junction with the Redwater, Black Hills,
South Dakota (type); Freezeout Hills, Wyoming (Logan).

Geologic horizon.—In red sandstones of Jurassic age 70 feet above the “Red Beds” (Whitfield
type); in a thin stratum of sandstone in the Jurassic bluish shale, No. 15 of the section (Logan),
Jurassic.

Collections.—U. 8S. National Museum (325); Kansas University Museum.

Subclass OPHIUROIDEA.

Order ZYGOPHIURA.
Family OPHIOLEPIDID &.
Genus OPHIOGLYPHA Lyman.

OPHIOGLYPHA UTAHENSIS Clark, n. sp.

p Plate III, figure 5.

Determinative characters—Dorsal or aboral surface of disk composed of numerous small
imbricating plates with five pairs of “radial shields.”’ Dorsal arm plates wider than high near
the disk, gradually becoming longer toward the extremity of the arms. Narrow lateral arm
plates shown on several of the arms.

Dimensions.—Diameter of disk 8 millimeters; length of arm 10 millimeters (not entire);
width of arm near disk 14 millimeters.

Description.—The only specimen of this species contains two individuals on the same slab
together with a few fragments of arm plates. The aboral surface of the disk of one individual
and several of the arms are in a good state of preservation. The surface of the disk is covered
with a very large number of nearly equal sized imbricating plates of rounded form with the excep-
tion of the “radial shields,”’ which are larger and elongate and stand in pairs at the head of the
arms. The arms are long, but all the outer extremities are broken, so that the full length can not
be determined. The dorsal arm plates are wider than high near the disk, but gradually lengthen
as the distance from the disk increases until they become longer than wide. The lateral arm
plates are preserved in places and appear as narrow plates more or less detached from the arms.
The spines are not clearly shown.

Locality—San. Rafael River 10 miles below Castledale, Utah.

Geologie horizon.—Jurassic.

Collection.—U. S. National Museum (22839).

39800°—15

2)
oO

30 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.
Class ECHINOIDEA.
Subclass REGULARIA ENDOBRANCHIATA.

Order CIDAROIDEA.

Family CIDARID®.
Genus CIDARIS Leske.

CIDARIS CALIFORNICUS Clark.

Plate IV, figures la-c.

Cidaris californicus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Cidaris californicus Clark, 1893, U. 8S. Geol. Survey Bull. 97, p. 36, Pl. VI, figs. la-b.

Determinative characters —Test unknown. Spines large, club-shaped, with rows of large
granules that coalesce to form longitudinal ridges which extend from neck to point of spine.

Dimensions.—Largest spine: Length 22 millimeters; breadth in thickest part 5 millimeters.

Description.—This species is based on detached spines, four or five specimens of which are
found in material from Taylorsville, Cal. They are distinctive in every way and can not be
mistaken, even in fragments. The specimens examined are casts but are so well preserved that
impressions in gutta-percha, from which the drawings were made, show the characters com-
pletely. Each spine has a short narrow neck, beyond which it rapidly mcreases im size so as to
give a club-shaped outline to the middle and upper portions. Rows of longitudinal granules
cover the surface from the neck to the point of the spine, presenting the appearance of long
serrated ridges.

Related forms.—Separated from C. taylorensis by its club-shaped form and surface char-
acters.

Locality.Taylorsville, Plumas County, Cal.

Geologic horizon.—Mormon sandstone, Middle Jurassic.

COollection.—U. S. National Museum (30184).

CmaARIS TAYLORENSIS Clark.

Plate IV, figures 2a-b.

Cidaris taylorensis Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.
Cidaris taylorensis Clark, 1893, U. S. Geol. Survey Bull. 97, p. 35, Pl. VI, figs. 2a-b.

Determinative characters—Test small. Interambulacra wide: Tubercles large, with cir-
cular areolas, much depressed marginally; boss crenulated; mamelon perforated. Miliary
space narrow. Spines long, cylindrical, covered with small granules arranged in longitudinal
rows.

Dimensions.—Test small but undetermined. Largest spine: Length 30 millimeters (?%);
width in broadest portion 5 millimeters.

Description.—The fragments of this form, although they permit determination of but few of
the important characters, warrant specific description from the fact that they are totally distinct
from the only other representative of Cidaris from the Jurassic rocks of America. The small
fragments of the interambulacrum and the spine occur together and doubtless formed part
of the same individual. The interambulacral plates, of which only portions are preserved
on the specimen figured, indicate a form of no great size. The tubercles are large, with depressed
areolas surrounded by a circle of large granules. The boss is crenulated and the mamelon per-
forated. The miliary space is apparently narrow, the tubercles of adjacent plates in the same
column being nearly confluent.

The spine is long, gently tapering toward the base in the portion preserved, and covered
with longitudinal rows of small granules.

Related forms.—As the Jurassic strata of North America afford few fossil Echinodermata as
compared with the Cretaceous, there are not many American types with which the present form

JURASSIC ECHINODERMATA. 31

may be compared. C. californicus is not known by its test and comparisons are limited to the
spines. In C. taylorensis the spines are long and cylindrical, while in C. californicus they are
short and thick set, and have a totally different surface decoration. C. taylorensis differs from
C. plumasensis in its smaller miliary space and circular areolas.

Locality —Taylorsyville, Plumas County, Cal.

Geologic horizon.—Harderave sandstone, Lower Jurassic.

Collection.—U. S. National Museum (30183).

CIDARIS PLUMASENSIS Clark, n. sp.
Plate IV, figure 3.

Determinatiwe characters —Test medium size. Ambulacra narrow. Interambulacra wide.
Tubercles large with oval depressed areolas, crenulated boss, and perforated mamelon. Miliary
space covered with coarse granules.

Dimensions.—Height of largest ambulacral plate 10 millimeters; width 14 millimeters.

Description—Fragments of casts of the test of this species are found on a single slab of
sandstone. The most perfect impression is of three interambulacral plates with adjacent ambu-
lacral plates. It is evidently part of the test of a form of medium size. The ambulacra are
narrow but the impression of the plates is obscure. The interambulacral plates are much better
preserved and show large tubercles with oval areolas, somewhat depressed. The boss is crenu-
lated and the mamelon perforated. The miliary space is rather wide and is covered with coarse
granules. ;

Locality.— Taylorsville, Plumas County, Cal.

Geologic horizon.—Hardgrave sandstone, Lower Jurassic.

Collection —U. S. National Museum (31191).

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder ARBACINA.

Family HEMICIDARID®.
Genus HEMICIDARIS Agassiz.
HEMICIDARIS INTUMESCENS Clark.

Plate IV, figures 4a-1.

Hemicidaris intumescens Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Hemicidaris intumescens Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 44, 45, Pl. XII, figs. la-i.

Determinatiwe characters.—Test spheroidal, upper surface inflated, lower surface flat. Am-
bulacra moderately broad, increasing in width from the apical system to the peristome. The
tubercles at the peristome are nearly equal in size to those of the interambulacral areas, but
become greatly reduced in passing from the ambitus to the apical system. Interambulacra
rather wide, with two rows of large tubercles. Miliary space wide, covered with numerous
granules. Peristome moderately wide, with deep incisions.

Dimensions.—Diameter 18 millimeters; height 12 millimeters.

Description.—The very perfectly preserved molds of the species permit the taking in gutta-
percha of all the details of form and structure. As the only representative of the genus in
American deposits it possesses considerable interest. The test is of moderate size, with a con-
vex and slightly inflated upper surface and nearly flat lower surface. The slightly flexuous
ambulacra broaden from the region of the apical disk toward the ambitus and slightly contract
again before the peristome is reached. The tubercles are prominent in the lower part of the
column, where several pairs attain a size nearly equal to those of the interambulacra. Minute
perforated granules succeed them above and continue as a double row to the apical system. The

32 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

poriferous zones are slightly flexuous, and the small pores are uniserially arranged, although
somewhat increased in the vicinity of the peristome.

The interambulacra are three to four times the width of the ambulacra at the ambitus. The
two rows of medium-sized tubercles occupy the center of the plates; the areola is circular and
slightly elevated; the boss deeply crenulated, and the mamelon distinctly perforated. There
are about eight primary tubercles in each row. The apical system is rather large, although not
sufficiently well preserved to admit of a determination of the individual plates.

The peristome is small and occupies scarcely one-half of the diameter of the test. It is
deeply notched, the lobes being nearly equal in size.

Related forms.—The present species of Hemicidaris is the only representative of the genus
known from American deposits. A comparison with Huropean species fails to identify it with
any described form.

Locality.—Taylorsville, Plumas County, Cal.

Geologic horizon.—Mormon sandstone, Middle Jurassic.

Collection.—U.S. National Museum (30187 and 30188).

Suborder DIADEMINA.

Family DIADEMATID A.
Genus PSEUDODIADEMA Desor.
PsEUDODIADEMA EMERSONT Clark.
Plate V, figures la-e.
Pseudodiadema emersoni Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 45, 46, Pl. XII, figs. 2a—e.

Determinative characters.—Test circular, depressed. Ambulacra straight and prominent;
poriferous zones narrow; pores uniserial. Interambulacra not quite twice the width of the
ambulacra with two rows of large tubercles, eight or nine in each row. Peristome wide.

Dimensions.—Diameter 15 millimeters; height 7 millimeters.

Description.—The beautifully preserved molds of this interesting form were collected by
Hyatt from the Jurassic beds of Taylorsville, Cal. The gutta-percha casts from which the draw-
ings were made represent very perfectly all the details of structure. The test is nearly circular,
the prominent ambulacra are rather more than one-half the width of the interambulacra, and
support two rows of primary tubercles somewhat smaller than the interambulacral tubercles.
There are nine or ten in each row. Between the tubercles are numerous granules that are
arranged in an undulating line between the rows and along the margin. They nearly disappear
between the tubercles of the same series. Toward the apical system the tubercles are greatly
reduced in size. The pores are uniserial, there being three or four opposite each ambulacral
plate.

The interambulacra bear two rows of primary tubercles, eight or nine in each, that are only
slightly larger than those of the ambulacral areas. They increase from the peristome to the
ambitus, after which they rapidly decrease in size. The areolas are nearly confluent above and
below, broader than long, and rise into prominent bosses that are not deeply crenulated. The
mamelon is distinctly perforated. The miliary space is covered with granules of different sizes.
There are no secondary tubercles developed near the peristome. The lower surface is flat, the
peristome large and deeply notched; the ambulacral lobes larger than the mterambulacral. The
apical system is not preserved. This species is named in honor of B. K. Emerson, of Amherst
College, from whom the writer received his first instruction in geology and paleontology.

Related forms.—The species is unique, being the only Pseudodiadema in the Jurassic of
America and being only very doubtfully identical with any European form. It resembles P.
baileyi from England in many particulars but is less depressed, has more rounded sides, and more
numerous granules in the miliary space.

Locality.—Taylorsville, Plumas County, Cal.

Geologic horizon.—Mormon sandstone, Middle Jurassic.

Collection.—U. S. National Museum (30186).

JURASSIC ECHINODERMATA, 33

Family PEDINID&.
Genus STOMECHINUS Desor.
STOMECHINUS HYATTI Clark.
Plate V, figures 2a-e.
Stomechinus hyatti Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Stomechinus hyatti Clark, 1893, U.S. Geol. Survey Bull. 97, p. 56, Pl. X XIII, figs. la-e.

Determinative characters—Test high, circumference circular. Ambulacra with four rows
of small primary tubercles; poriferous zones wide, triserial. Interambulacra with eight or ten
rows of tubercles that diminish in number toward apical system and peristome, with a depression
along the line of the central suture.

Dimensions.—Diameter 25 millimeters; height 25 millimeters.

Description.—Only the cast of a portion of the exterior of a single specimen of this interest-
ing Jurassic form is preserved. The test is high, and the circumference circular or slightly sub-
pentagonal. The sides rise abruptly from the margin.

The ambulacra are about one-half the width of the terambulacra and preserve a nearly
uniform width threughout. There are four rows of tubercles that increase gradually in size
from above downward. A depression appears along the line of the central suture. The porif-
erous zones are wide; the pore pairs are placed in oblique ranks of three, and each rank is
separated from that next to it by two small tubercles.

The interambulacra are about twice the width of the ambulacra and the plates of the former
are but slightly higher than those of the latter. Each plate is covered at the widest part of the
area with an irregular row of four or five tubercles that are of about the same size as those of the —
ambulacra. The tubercles are uncrenulated and imperforate. A wide depression extends
along the medial line of each interambulacral area, according with the position of the central
suture. ;

The regions of-the apical disk and peristome are largely wanting, but a deep incision shown
upon the margin of the latter indicates that it is distinctly lobed throughout.

Related forms.—The American species shows some points of identity with Stomechinus nudus
Wright of England but is more elevated, has a less sharp marginal angle, and has a more regular
arrangement of the tubercles.

Locality.—Taylorsyville, Plumas County, Cal.

Geologic horizon.—Mormon sandstone, Middle Jurassic.

Collection.—U. 8. National Museum (30185).

Subclass IRREGULARIA.
Order GNATHOSTOMATA.
Suborder HOLECTYPINA.

Family PYGASTERID ®.
Genus HOLECTYPUS Desor.
Horecrypus PEALE! Clark, n. sp.
Plate V, figures 3a-b.

Determinative characters—Test subcircular, subconical. Ambulacra rather narrow, nearly
straight; poriferous zones distinct. Interambulacra prominent with large plates. Apical system
imperfect.

Dimensions.—Diameter 15 to 25 millimeters; height 10 to 15 millimeters.

Description.—Several casts of a typical Holectypus from the Jurassic beds of Yellowstone
River were collected by Peale in Montana many years ago but were never described. _ More
recently a still more perfect specimen was obtained by W. H. Weed from the Yellowstone
National Park, and this is made the type of the species. The specimens show the characteristic
features of both the ambulacra and interambulacra, but the adoral and aboral regions are poorly
preserved, as a result of which the characters of the apical system, peristome and periproct are

34 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

unknown. The ambulacra are very distinct, the poriferous zones showing clearly.. The ambu-
lacra are narrow, increasing in width gradually to the ambitus. The interambulacra stand out
prominently, the sutures between the plates being clearly indicated.

Locality.—North of Berry Creek, Yellowstone National Park, Wyo.

Geologic horizon.—Jurassic.

Collection.—U. S. National Museum (31192).

Hoxtrcryrus craGini Clark, n. sp.
Plate V, figure 4.
Holectypus ? sp. Cragin, 1905, U. 8. Geol. Survey Bull. 266, p. 35.

Determinative characters.—Test subcircular, subconical. Ambulacra narrow, straight, with
several rows of tubercles; poriferous zones straight and narrow. Interambulacra wide. Apical
system imperfect.

Dimensions.—Diameter 28 millimeters; height 15 millimeters.

Description.—The fragmentary specimen referred to by Cragin is an unquestioned Holec-
typus and presents many of the diagnostic characters of that genus. It is not unlike H. planatus
in general outline, but its much earlier geologic position renders it necessary to place it in an inde-
pendent species. The test is much damaged, so that its essential specific characters can not be
determined. The outlines of the ambulacra and interambulacra can be seen, but the individual
plates are with difficulty distinguished. The ambitus is relatively sharp, indicating a flat under-
surface. The tubercles in this species are evidently small and cover the greater portion of the
plates. The apical system is small but the individual plates can not be distinguished.

Related forms.—This species is wholly unlike H. peali in form and is evidently a different
species.

Locality —Malone Mountain, Texas.

Geologie horizon.—Malone formation, Upper Jurassic.

Collection.—U. S. National Museum (31193).

Order ATELOSTOMATA.
Suborder ASTERNATA.
Family CASSIDULID.
Genus PYGURUS Agassiz.

PYGURUS sp.

Pygurus sp. Cragin, 1905, U. S. Geol. Survey Bull. 266, p. 36.
Description.—Cragin describes the form as follows:

Among the specimens submitted by Dr. Stanton is a fragment of the test of a sea urchin of the genus Pygurus. It
includes the main part of the aboral half of an ambulacrum. The genus is clearly determined by the form of the
ambulacrum and the form and arrangement of the pores, as well as by the character of the tubercles and by the dis-
coidal form of the test, the latter form being indicated by the flatness of the part preserved. The ambulacrum has the
biconcave outline that characterizes the upper part of that of Pygurus. The pores of the outer row are very long and
slitlike, widened slightly toward the outer end, and subhorizontal to more or less oblique; those of the inner row more
ringent, compressed dotlike or hyphen-like, and oblique, their width being considerably less and their length consid-
erably more than that of any of the circumtubercular courts on the neighboring part of the ambulacrum. The ambu-
lacral plates are exceedingly narrow; the imperforate part of each, in the widest part of the ambulacrum, being about
10 times as long (transverse) as wide (parallel to the course of the ambulacrum) and ornamented with 1 to 3 small
perforated tubercles, each of which is set in a round, depressed court. The distinction of these tubercles is irregular,
but they are so few and so feebly developed on the inner ends of the plates as to give the ambulacrum the aspect of
having a median plain zone, to which the seams between the plates give a transversely striated appearance.

Measurements. Maximum width of ambulacrum 16, of which the two pore belts each occupy 3.5 and the imper-
forate tract 9 millimeters; length and width of each imperforate part of an ambulacral plate in broadest part of the
ambulacrum, respectively, 4.5 and 0.43 millimeters; length of outer slitlike pores in broadest part of ambulacrum 2
millimeters, which is about one-fourth of the width of a semiambulacrum.

Oceurrence.—West side of Malone Mountain, about 2 miles southwest of Malone station, in No. 25 of Dr. Stanton g
Malone Mountain section; with Gryphxa mexicana, Pleuromya inconstans, Pinna quadrifrons, etc.

Geologic horizon.—Jurassic.
Collection.—U. S. National Museum.

CRETACEOUS ECHINODERMATA.
Class CRINOIDEA.
- Subclass DICYCLICA.

Order INADUNATA.
Suborder DENDROCRINOIDEA.
Family PENTACRINID#®.

Genus PENTACRINUS Blumenbach.
PENTACRINUS TEHAMAENSIS Clark, n. sp.
Plate VI, figure 1.

Determinative characters —Column composed of small and medium sized pentagonal joints,
some with and some without sharp reentering angles. Crenulated ridges petaloid. Column
perforated by a small canal.

Dimensions.—Column: Diameter of joint 3 to 6 millimeters; thickness of joint 4 to 1
millimeter.

Description —Numerous isolated fragments of Pentacrinus columns have been found in
the California Cretaceous. The larger joints are of medium size. Many very small joints are
found with the larger ones and probably belong to the same species. The crenulations are dis-
tinct and form five well-marked petaloid areas on the upper and lower surfaces of the joints.
The column is perforated by a small central canal.

Localities.—Shelton’s ranch, 5 miles north of Paskenta, Tehama County (type), and Texas
Springs, Cal.

Geologic horizon.—Knoxville formation, Lower Cretaceous, and beds doubtfully assigned to
the lower part of the Chico formation, Upper Cretaceous.

Collection.—U. S. National Museum (31194).

PENTACRINUS BRYANI Gabb.
Plate VI, figures 2a-b.

Pentacrinus bryani Gabb, 1876, Acad. Nat. Sci. Philadelphia, Proc., vol. 28, p. 178, Pl. V, figs. 1, la, 1b.

Pentacrinus bryani Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.

Pentacrinus bryani Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 28, 29, Pl. III, figs. 3a-b.

Pentacrinus bryani Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.

Pentacrinus bryani Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 276-277, Pl. VI,
figs. 8, 9.

Determinative characters—Column composed of moderately large, rather thick, pentagonal
joints, with sharp reentering angles. The crenulated ridges are broadly petaloid and each area
is rounded at its outer extremity. Column perforated by canal of medium size.

Dimensions—Column: Diameter of joint 6 millimeters; thickness of joint 1 millimeter.

Description.—Two small fragments of the stem of this form were described by Gabb in 1876.
As the first representative of this family reported from the American Cretaceous it possesses
considerable interest. The column is composed of moderately large, thick joints, that reach
about 6 millimeters in diameter and about one-fifth of that in thickness. The broad, rounded
ridges at the salient angles of the pentagonal outline form a nearly unbroken line, and the furrow
at the reentering angles is alternately depressed and elevated in successive joints. The edge

35

36 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

of each joint is slightly rounded. The crenulated surfaces form five broad petaloid areas dis-
tinctly rounded at the outer extremities and unite near the inner edge of the reentering angles
to form a double flat-topped ridge that reaches to the central canal, around which there is like-
wise a slight eleyation. The crenulations are clearly visible on the outer surface of the column.
The column is perforated by a central canal of medium size.

Related forms.—This species is quite unlike other species of American Pentacrinide and is
distinguished from Pentacrinus tehamaensis Clark of the Pacific coast by its deeper reentering
angles.

Locality —Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections —Academy of Natural Sciences of Philadelphia (1458) ; Johns Hopkins University.

Family UINTACRINID&.
Genus UINTACRINUS Grinnell.
UINTACRINUS SOCIALIS Grinnell.
Plate VI, figures 3a—h; Plate VII, figures la-c.

Uintacrinus socialis Grinnell, 1876, Am. Jour. Sci., 3d ser., vol. 12, pp. 81-83, Pl. IV, figs. 1-2b.

Uintacrinus socialis Meek, 1876, U. S. Geol. and Geog. Survey Terr. Bull., vol. 2, No. 4, pp. 375-378, figs. A-B.
Uintacrinus socialis Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 21-24, Pls. I, II.

Uintacrinus socialis Williston and Hill, 1894, Kansas Univ. Quart., vol. 3, No. 1, pp. 19-21 and diagram.
Uintacrinus socialis Bather, 1896, Zool. Soc. London Proc. for 1895, pp. 974-1004, Pls. LIV-LVI, 13 figs.
Uintacrinus socialis Logan, 1898, Kansas Univ. Geol. Survey, vol. 4, pp. 481-483, Pls. XXI, CXII.
Uintacrinus socialis Beecher, 1900, Am. Jour. Sci., 4th ser., vol. 9, pp. 267-268, Pls. III, IV.

Uintacrinus socialis Springer, 1900, Mus. Comp. Zool. Mem., vol. 25, No. 1, pp. 1-89, Pls. I-VIII.
Uintacrinus socialis Schuchert, 1904, Smithsonian Misc. Coll., vol. 45, p. 450, Pl. CIII.

Uintacrinus socialis Bassler, 1909, Smithsonian Misc. Coll., vol. 52, pp. 267, 269, Pls. XVII, XVIII.

Determinative characters—Calyx globose; composed of very thin, usually rather flat,
although sometimes decidedly convex plates, joined together by a very loose suture; faces at
times marked by faint, irregular, vertical grooves. Column wanting. Base or apical system
probably dicyclic, composed of centrale surrounded by circlet of basals (B) or circlet of infra-
basals (IB) and basals (B) as the ease may be. Encircling the base and alternating with the
basals are five abutting radials (R) either heptagonal or hexagonal in form. Succeeding the
radials are two primary brachials (IBr) the second (IBr2) axillary and generally pentagonal in
form; separated by interbrachials (Br) which may vary in number from 3 or 4 to 23. Branch-
ing from the axillary brachial are the secundibrachs (IBr) or distichals, generally the first
eight of which are fixed, entering into the composition of the dorsal cup. Between the secundi-
brachs are intersecundibrachs (IIB) or the interdistichals, which with the lower pimnulars
and the interpinnulars of all areas are fixed. The normal order of succession of pinnulars is
I1Br2 outer J]Br4 inner IIBr5 outer I]Br7 inner ITBr8 outer, beyond which each brachial bears
a pinnule on alternate sides except where there is a syzygy, when only the epizygal is pinnule-
bearing. Ventral disk or teemen composed of plates skin covered with small calcareous plates
or spicules. Mouth excentric, the ambulacra diverging from point near margin of disk. Anus
central, large and conical.

Dimensions.—W idth of calyx 6.25 to 75 millimeters; medium-sized specimen 40 millimeters;
length of arms 100 centimeters.

Description.—The writer of this paper gaye in 1893 a more extended description of Uinta-
crinus socialis than his predecessors had done and was able for the first time to show the struc-
ture of the base, which was fairly well preserved on a single specimen. The small amount of
material at his disposal rendered it impossible to detect some important structural features
observed by later writers who had access to more abundant and better preserved specimens.

S. W. Williston and B.H. Hill described better specimens of Uintacrinus socialis found by
E. E. Schlosson in Logan County, Kans. Williston pointed out that these were the first speci-

CRETACEOUS ECHINODERMATA, 37

mens found in place and unweathered. He says that the long arms were so entangled as to make
it very difficult to trace them to their extremity.

The collection by H. T. Martin of a large number of specimens of Uintacrinus socialis from
Williston’s locality in western Kansas furnished several museums, among them the British
Museum and the Peabody Museum of Yale University, with new and valuable material. The
material acquired by the British Museum was very thoroughly studied in 1895 by F. A. Bather,
whose morphologic study of this species added much to what was previously known. A large
slab acquired by Yale University was described by C. E. Beecher in 1900.

The complete description of Uintacrinus socialis and the true interpretation of its structure
and relations were not made until 1901, when Springer obtained from western Kansas, through
the intelligent collecting of H. T. Martin, a large and finely preserved lot of specimens, far more
than had come into the possession of any of his predecessors. With his wide and accurate knowl-
edge of the crinoids he has been able to add more than any of his predecessors to a knowledge of
this interesting form and in addition to the discovery of dicyclic as well as monocyclic individuals,
was also able to find a number of specimens with well-preserved tegmens so that for the first
time a knowledge of the structure of the ventral surface of Uintacrinus was secured. The fol-
lowing description is largely based on Springer’s elaborate discussion of this form.

The calyx is globose with 10 long simple arms bearing pinnules. The test must have been
flexible. The calyx plates are thin, frequently convex and joined together by loose sutures, the
faces of which are at times slightly grooved. The calyx is without column or stalk and belongs
to the class of free forms.

The basis is composed of a centrale, surrounded by either a circlet of basals or a circlet of
infrabasals, which are in turn surrounded by the basals. The centrale in the first form has its
angles radially directed and in the second interradially directed. The form is, however, proba-
bly dicyclic. The infrabasal circlet is not complete in all specimens, some having only 4, 3, 2, or
even 1 infrabasals.

The radials are five in number and surround the basals, with which they alternate. They are
equal, six or seven-sided, the latter occurring where the edge toward the basis forms a reentrant
angle. The radial plates are wider than high and come in contact with one another only in the
lower portions of each side. They come in contact with the proximal interbrachials and support
the first primibrachs.

Following the radials are the primibrachs, secundibrachs or distichals, and fixed pinnules,
all of which enter into the formation of the calyx, to which are added imterbrachials, interdis-
tichals, and interpinnulars. It is not always easy to determine the exact limits of marginal.
attachment of the fixed brachial elements in the fossil state. There are two primibrachs, the
first (IBr1) hexagonal in form abutting on the radial on its lower margin, and the second primi-
brach ([Br2) on its upper margin where latterly it comes into contact with interbrachials on either
side. Both the first and second primibrachs are somewhat narrower than the radials. The
second primibrach is axillary and generally pentagonal in form. It also abuts on interbra-
chials on either side and bears upon its upper margin the first of the secundibrachs.

The secundibrachs or distichals are commonly fixed in the first eight plates with the aid of
the fixed pinnules, interbrachials, interdistichals, and interpinnulars. Those secundibrachs
bearing fixed pinnules appear slightly axillary, which gives the appearance of a somewhat irregu-
larly depressed series.

The normal order of succession of the fixed pinnules is first from the second secundibrach on
the outer side, the next from the fourth secundibrach on the inner side, then from the fifth secun-
dibrach on the outer side, then the seventh secundibrach on the inner side, and finally from the
eighth secundibrach on the outer side. The intervening secundibrachs do not bear pinnules.
Beyond this point each brachial bears generally on alternate sides a pinnule except where there
is a syzygy when only the epizygal bears a pinnule. The fixed pinnules comprise four or five to
ten of the proximal plates. The number of plates is greater in adults than in the young forms.
United with the interbrachial and in many specimens with the interpimnular plates they form
the interbrachial area of the calyx, and with the intersecundibrachs or interdistichals the inter-

38 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

distichal area of the calyx. Each interbrachial area contains in adults, usually six rarely eight,
of these fixed pinnules. In the young four and even two have been found. The interdistichal
area contains four fixed pinnules in adult forms and two, and at times apparently none, in the
young. The amount of fixation therefore increases with age.

The interbrachial area consists of from three or four to twenty-three plates. The arrange-
ment of the plates is very variable. When there are seven plates or less no one of the inter-
brachials is inclosed, but the plates are disposed in more or less irregular vertical rows. This
arrangement holds in some specimens containing eight or even nine or ten plates. In other
specimens one or more plates are inclosed. Variation in the interbrachial areas occurs in some
individuals.

The intersecundibrachs or interdistichals may differ in the same way, the number varying
from none to 8, although the most common number is from 2 to 5, the younger forms having less
than the adults. The interpinnular plates are not present in all specimens, but one or two may
be placed between the proximal portions of the fixed pmnules and the intervening secundibrachs.
The interpinnulars generally appear in corresponding position on opposite sides of the same area.

The arms are the continuation of the secundibrachs or distichals and are therefore ten in
number. They consist of brachials and pmnules, the latter disposed in the manner previously
described. An arm branch 100 centimeters, or 40 inches, long has been described by Springer,
who thinks it not improbable that a total spread of arms of 250 centimeters, or 8 feet 4 inches,
may have occurred.

The ventral disk or tegmen has been described only by Springer, who prepared a number of
specimens on which the disk was beautifully preserved. He states that it is composed of the
plated skin, the membrane being of such a highly carbonaceous composition that it is jet black
in the fossil. This membrane evidently inclosed the entire visceral mass and formed a lining
where it is usually seen when the calyx is broken away. Upon the disk it is studded or paved
with small calcareous plates or spicules which are not connected by suture but are embedded in
the tegment touching each other. They are of irregular shape, variable in size, and without any
definite plan of arrangement.

The central part of the disk is occupied by a large, conical anal tube, shaped like an inverted
funnel, which is perhaps an extension of the ventral disk above described. It is also composed
of a plated skin, the granules of the disks passing gradually into it and becoming more and more
elongate, until toward the distal end where the opening was they become threadlike.

The mouth is excentric, and the ambulacra diverge-at a point near the margin of the disk.
Two of them follow around the margin in a large hood-shaped cone, closing the anal tube.
These branch on either side so as to connect with the arms of the posterior rays. The next pair
of ambulacra are shorter; they branch and supply two lateral rays. A single groove runs to
one branch of the anterior ray and the other branch does not seem to have any groove leading to
it. The ambulacral grooves are simply depressions in the peristome. There is no trace of any
covering plates or anything like an ambulacral skeleton.

Localities.—The first specimen of this species was found by O. C. Marsh in the Uinta Moun-
tains, Utah. Grinnell established the genus Uintacrinus on much better preserved material’
‘from Trigo County, Kans. Still better specimens were later found in Logan County, Kans., which
has been the source of most of the fine material m the various museums of the world. It is from
this locality that Springer secured a few years ago the superb specimens that are the basis of
his elaborate monograph.

Geologic horizon.—Niobrara chalk, Upper Cretaceous.

Collections—Museum of Comparative Zoology, Cambridge; U.S. National Museum (8044);
University of Kansas; Yale University; British Museum; Johus Hopkins University.

CRETACEOUS ECHINODERMATA, 39

Family MARSUPITID&.

Genus MARSUPITES Miller.

MARSUPITES AMERICANUS Springer.
Plate VII, figures 2a, 2b, 3.
Marsupites americanus Springer, 1911, Mus. Comp. Zool. Mem., vol. 25, No. 3, pp. 158-161, Pl. VI, figs. da, 4b, 5.

Springer describes the species as follows:

Determinative characters.—Calyx globose, wider than high; widest about middle of basal, contracting toward the
arm bases. Centrale larger than infrabasals. * * * Radial facets shallow, facing almost vertically; filling about
half the distal face of radial, and having a straight muscular articulation. Primibrachs 2; succeeding brachials to the
number of seven in the longest arm preserved wide and very short, with an alternating cuneiform arrangement and an
indication of syzygies between Br3 and 4; ventral groove broad and shallow. A good-sized triangular interbrachial
plate, having straight sides and apparently joined to the brachials by suture, fills the space between the arm bases. All
plates very thin, and covered with moderately fine radiating striee crossing the sutures and converging at the centers;
a strong ridge runs upward from the center of the basals, two meeting at each radial facet. Furtherstructures unknown.

Dimensions.—Centrale: Diameter of pentagon 18 millimeters; IBB 17 millimeters high by 17.5 wide; BB 18 milli-
meters high by 18 wide; RR 11 millimeters high by 14 wide; radial facets 6 millimeters wide. Ina large fragment the
centrale is 25 millimeters wide.

Description.—The general outline and surface ornament of this species are not different from what may be seen

“among specimens of I. testudinarius of the English chalk from Sussex and other places. These vary from coarse to fine
strie and with such a thin, plant calyx the contour of the fossil is largely a matter of pressure in its deposition. Meas-
urements of plates shows no substantial difference between the two, an average of five specimens of the English species
being as follows: Centrale, 19.1 millimeterswide; IBB,19.6 millimeters high by 19.5 wide; BB, 19.6 millimeters high
by 20.1 wide; RR, 12.6 millimeters high by 15.7 wide; R, facets 8 millimeters wide. The only real difference observ-
able in the parts preserved is that in our species the brachials are shorter and wider than in J. testudinarius; and if we
had enough specimens with brachials attached to get an average, this might disappear. The calyx figured is smaller
than the English species usually appears, but the other fragmentary specimen has plates fully as large as that. The
species is rare and has only been found at the type locality.

Locality.—Plymouth Bluff, Miss.
Geologic horizon.—Tombigbee sand member of the Eutaw formation, Upper Cretaceous.
Collection.—Collection of Frederick Braun.

Order FLEXIBILIA.
Suborder PINNATA.
Family BOURGUETICRINID#.
Genus RHIZOCRINUS M. Sars.
RHIZOCRINUS ALABAMENSIS (De Loriol).

Plate VII, figures 4a-c.

Bourgueticrinus alabamensis De Loriol, 1882, Cincinnati Soc. Nat. Hist. Jour., vol. 5, p. 118, Pl. V, figs. 1, 1a, Ib.
Rhizocrinus alabamensis Carpenter, 1884, Challenger Repts., vol. 11, pt. 2, p. 257.

Bourgueticrinus alabamensis Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.

Bourgueticrinus alabamensis Clark, 1893, U.S. Geol. Survey Bull. 97, p. 25, Pl. IIT, figs. la-e.

Description.—As it has been impossible for the writer to obtain possession of the type of this
species the description of De Loriol, as translated by S. A. Miller, is given verbatim:

This species is as yet known only by the basal cone which supports the calyx, and which is composed of several
enlarging segments of the column surmounted by the basal plates. The height of the inverted cone is 5 millimeters;
the diameter of the basal plate is 34 millimeters; and that of the inferior sezment of the column is 3 millimeters in its
major axis. Its form is faintly swollen in the middle; the surface issmooth. The sutures are very indistinct, and itis
a dificult matter to determine what was the height of the basal plate. The superior face of the cone carries five slender
and compatively elevated radiating ridges, which bound five deep depressions in which the basal pieces of the calyx
were lodged; in the center an enlargement of the central canal constitutes the bottom of the calyx cavity. The articu-
lar face of the lower joint of the column forming the inferior end of the cone is elliptical, but the leneth of its major
axis does not, however, much exceed that of its minor axis. It is slightly concave and encircled by a feeble rim along

40 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

the circumference line; the transverse articular ridge process is reduced to two elongated tubercles which proceed from
the marginalrim. Central canal comparatively large.

Although this species is still very imperfectly known one can affirm that it is certainly distinct from Bourgueticrinus
ellipticus Miller, by the much less swollen form of the basal cone, which is but slightly convex in outline, and by the
facts that the lower segment of the cone is already elliptical and already possesses the rudiments of a transverse articular
ridge. Furthermore, the radiating carinze are very much more salient, and consequently the depressions which they
separate very much deeper. Finally, by its central canal being relatively much larger.

This species is referred to the genus Rhizocrinus, following the views of Carpenter and also
from the possible close relationship OF the form to Rpeacrines inten ‘Welles from New Jersey.

Locality —Livingstone, Ala. (De Loriol).

Geologic hor ‘aor formation, Upper Cretaceous.

Collection.—Cincinnati Society of Natural History.

RuHIzOcRINUS CYLINDRICUS Weller.
Plate VII, figures 5a-g.

Rhizocrinus cylindricus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 275, 276,
Pl. V1, fig. 1

Determinative characters.—Weller says:

Calyx cylindrical, slender and greatly elongate, the sides almost straight, not enlarging from the basals up. The
proximal column joint (or joints ?) higher than the basals and radials together, cylindrical above with straight sides,
slightly contracted below. Basals much higher than the radials. Radial facets shallow, curved, rather wide, separate,
low and not sloping upward, having no conspicuous muscle plate or ligament fossa. They inclose a relatively large and
well-excavated central funnel or visceral cavity.

Dimensions.—Height of proximal column joint and calyx together 9.3 millimeters; diameter
3 millimeters; height of proximal column joint 6 millimeters. Isolated joints: width 2 to 4
millimeters ; ines 3 to 3.5 millimeters.

Desert migara. hts species is established on a single complete calyx and proximal stem
joint, although numerous isolated column joints may belong to the same species. Several of
these column joints were collected a number of years ago by the author. Figures of some of the
more characteristic ones were first given by Weller from drawimgs furnished by the author and
are repeated here.

Related forms.—The specimen is clearly a member of the family Bourgueticrmide and
superficially resembles in some respects Bourgueticrinus ellupticus and B. equalis from the White
Chalk of England, but it differs from these species in the much greater height of its basals. The
character of the radial facets and the larger viceral cavity, however, seem to remove it from
that genus. In the great height of its basals the species agrees with members of the genus
Rhizocrinus, but that genus is described as having a thin, disklike proximal stem joint, whereas
the New Jersey species apparently has an exceedingly high one in which no transverse divisions
can be detected. There seems to be no reason, however, why some latitude may not be allowed
in this character. The genus Rhizocrinus has not heretofore been recognized earlier than the
Eocene, but there is no reason why it should not also occur in the later Cretaceous.

The species is possibly allied to Rhizocrinus alabamensis (De Loriol) but diffe-s from that
species in having a much more slender form.

Toei. —incontoum, N. J.

Geologic horizon.—Vincentown sand of the Rancocas group, Upper Cretaceous.

Collection.—New Jersey Geological Survey; Johns Hopkins University.

CRETACEOUS ECHINODERMATA. Al
Class STELLEROIDEA.
Subclass ASTEROIDEA.

Order PHANEROZOMA.
Family ASTROPECTINID ®.
Genus ASTROPECTEN Schulze.
ASTROPECTEN (?) MonTANUS Douglas.
Plate VII, figure 6.
Astropecten montanus Douglas, 1903, Carnegie Mus. Ann., vol. 2, pp. 5-8, text fig.

Determinative characters.—Douglas says: “Size small; arms narrow and gradually tapering,
longer than the diameter of the body; five radial elliptical figures on body, all except one nearly
in line with the long axis of the arms.”

Dinecnsione-—anonn the central pit to end of perfect arm 12 millimeters. From central
pit to margin of body between the arms 3.5 millimeters.

Donan. —Douglas in his description of the form says that the most prominent markings
are the pits which probably represent the marginal plates. It is possible, however, that Miheas
may be impressions of the ambulacra. Halfway from the base to the end of the arm each row
of pits is nearly as wide as the middle portion of the arm. Only one arm is complete. This has
12 pits on each side and they are opposite.

Locality—South fork of Sixteenmile Creek, 23 miles north of Bozeman, Mont.

Geologic horizon.—Colorado shale, Upper Cretaceous.

Collection.—Carnegie Museum, Pittsburgh (601).

Family PENTAGONASTERID®.
Genus PENTAGONASTER Schulze.
PENTAGONASTER BROWNI Weller.

Plate VII, figure 7.

Pentagonaster browni Weller, 1905, Jour. Geology, vol. 13, pp. 257, 258, fig. 1.

Determinative characters—Weller says: ‘‘Stellato-pentagonal in outline. Disk large,
apparently flat. Interradial area broadly rounded and rays elongate for the genus, rounded at
the extremities. Marginal plates large, about sixteen occupying each interradial are from tip
to tip of adjacent rays, the character of their ornamentation not preserved.”

Dimensions.—Major radius 24 millimeters; minor radius 11. 4 millimeters.

Description.—The specimen is apparently exposed from its dorsal side, but apart from the
large marginal plates all the plates of this surface have been destroyed. The impressions of the
ambulacral furrows of the ventral surface are exposed by the weathering away of the dorsal sur-
face, and appear as rounded slightly elevated ridges extending from the arm pits to the center of
the disk, but the characters of the ambulacra are not sufficiently well preserved to be accurately
determined.

The presence of highly developed marginal plates on the specimen mark it at once as a
member of the order Phanerozonia, and it may be placed, without serious question, in the family
Pentagonasteride. The reference of the specimen to its proper genus is less satisfactory, but
it seems to agree more closely with Pentagonaster than with any other, although the interradial
arcs are somewhat deeper than is usual in that genus. In the recent species P. arculatus Sladen,!
however, these arcs are nearly as deep as in the fossil specimen, the proportion between the
minor and major radii being 1 to 1.93, against 1 to 2.08 in the fossil specimen.

1 Challenger Reports, Zoology, vol. 30, p. 277, Pl. LII, figs. 1, 2.

42 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The specimen also more or less closely resembles, in the characters preserved, some of the
recent species of Gnathaster, a genus also belonging to the family Pentagonasteridx, in which
the interradial ares are in many specimens much deeper than in Pentagonaster, the proportion
of the minor to the major radii in G. elongatus Sladen * being 1 to 3.5. Gnathaster, however, is
customarily characterized by the presence of an odd interradial marginal plate, a character not
clearly shown in the fossil specimen. In one of the interradia such a plate seems to be present,
but in the others not. For the present, therefore, the specimen may be referred to the genus
Pentagonaster (Weller).

Locality SE. } sec. 16, T. 32 N., R. 99 W., near Lander, Wyo.

Geologic horizon.—Montana group, Upper Cretaceous.

Collection.—Walker Museum, Chicago.

Family ATHENEID®.

Genus GONIASTER Agassiz (em. Per.).
GONIASTER MAMMILLATA Gabb.

Plate VIII, figures la-h.

Goniaster mammillata Gabb, 1876, Acad. Nat. Sci. Philadelphia Proc., vol. 28, pp. 178, 179, figs. 2, 2a, 2b.

Goniaster mammillata Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.

Goniaster mammillata Clark, 1893, U. 8. Geol. Survey Bull. 97, p. 32, Pl. V, figs. la-h.

Goniaster mammillata Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.

Goniaster mammillata Weller. 1907. Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 277-278,
P1.VI, figs. 10-17.

Determinative characters —Body pentagonal, provided with a dorsal and a central row of
marginal plates that are narrower than high, and distinctly tumid on their outer surfaces. Only
detached marginal plates preserved.

Dimensions.—Plates: Height 3 to 8 millimeters; thickness 2.5 millimeters.

Description —Gabb mentions the discovery of about thirty detached marginal plates of
this species. Many more have been found by the author. They differ widely in shape from
their position on the margin, but among those examined the majority are higher than wide and
are swollen on the outer surfaces. Certain of the plates show marked protuberances upon the
general level of the plate. The surface of the plates is punctate, the small depressions being
arranged in rows that cross one another at right angles.

Related forms—No American forms are similar enough to this species to be confounded with
it. Lack of knowledge of all characters except those of a few marginal plates renders wide
comparisons impossible.

Locality — Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections—Academy of Natural Sciences of Philadelphia (1457); Johns Hopkins
University.

Family PENTACEROTID.
Genus PENTACEROS Linck.

PENTACEROS ASPERULUS Clark.

Plate VIII, figures 2a—-b.
Pentaceros asperulus Clark, 1907; in Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 278-
279, Pl. VI, figs. 18, 19.
Determinative characters —Body pentagonal with long, narrow arms; covered with irregu-
larly shaped plates that touch intermittently at their margins, the surface uneven and bearing
spines. Detached body plates alone found.

1 Idem, p. 288, Pl. XLVIII, figs. 1, 2.

CRETACEOUS ECHINODERMATA, 43

Dimensions.—Type specimen: Length 6.5 millimeters; width 4 to 5 millimeters; thick-
ness 3.5 millimeters.

Description.—Two or three well-preserved specimens of the small surface plates of a Penta-
ceros have been found by the writer. They are so highly characteristic that their generic rela-
tions are clearly apparent. As no other Cretaceous representatives of this genus have been
found in American deposits they have been given a specific name.

The plates are irregular in outline, the intermittent articulating surfaces on the perimeter
producing a roughly polygonal outline. The surface of the plates is uneven, the irregularly
flattened areas providing attachment for spines. The central portion of the plates is higher than
the truncated margins.

Related forms.—No other American Cretaceous representatives of this genus are known,
and the plates can not readily be associated with any known European species.

Locality — Vincentown, N. J.

Geologie horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection—Johns Hopkins University (T 3014).

Subclass OPHIUROIDEA.
Order ZYGOPHIUR.
Family OPHIOLEPIDID®.

Genus OPHIOGLYPHA Lyman.
OPHIOGLYPHA TEXANA Clark.
Plate VIII, figures 3a-c.

Ophioglypha texana Clark, 1893, U. S. Geol. Survey Bull. 97, p. 30, Pl. IV, figs. la-c.

Determinative characters —Disk round; composition indistinct. Arms long, with wedge-
shaped under-arm plates about as wide as long; upper arm plates about twice as wide as long.

Dimensions.—Diameter of disk 4 millimeters; length of arm 50 millimeters; width of arm
at disk 2 millimeters.

Description —The determination of this species is dependent on three fairly well preserved
forms that are grouped upon a single slab of limestone, all with the lower side exposed. The
surface upon which they rest is considerably weathered, and many of the details of structure
have consequently suffered. The general form of the disk is preserved, although its composition
can not be made out. Many of the arm plates have disappeared, leaving only the skeletal
pieces. Where preserved, the under-arm plates are wedge-shaped and about as wide as long.
The upper-arm plates, which are shown only as impressions upon the limestone, are nearly twice
as wide as long and have their lateral edges rounded.

Locality. Six miles north of Fort Worth, Tex., on the banks of Fossil Creek. Associated
with Ostrea quadriplicata Shumard, Stearnsia robbinsi White, and Leiocidaris hemigranosus
(Shumard).

Geologic horizon.—Denison formation of the Washita group, Comanche series, Cretaceous.

Collection.—U. S. National Museum (21884).

OPHIOGLYPHA BRIDGERENSIS (Meek).

Plate VIII, figures 4a-b.

Ophioderma? bridgerensis Meek, 1873, U. 8. Geol. and Geog. Survey Terr. Rept. for 1872, pt. 2, p. 475.
Ophioderma? bridgerensis White, 1883, U. 8. Geol. and Geog. Survey Terr. Rept. for 1878, pt. 1, pp. 8, 9, Pl. XT, fig. 2a.
Ophioglypha bridgerensis Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Ophioglypha bridgerensis Clark, 1893, U. S. Geol. Survey Bull. 97, p. 29, PL. IV, figs. 2a-b.

Determinative characters —Disk composed of numerous small imbricating plates. Upper-
arm plates wider than long, the outer angles sharp and extending between the side-arm plates,
which are slightly smaller. Under-arm plates long and nearly rectangular in shape.

44 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions.—Diameter of disk 5 millimeters; length of arm 20 millimeters; width of arm
near disk 14 millimeters. ,

Description.—The single specimen of this species thus far found is described in a footnote to
a list of specimens reported by F. B. Meek in 1872, and redescribed and figured by C. A. White in
1878. This specimen, which has been carefully examined by the writer, presents the upper sur-
face of the disk and fragments of the five arms. Upon four of the fragments the upper and side
arm plates are shown, and upon the fifth a small portion of the under surface with the under arm
plates and ambulacral openings is preserved.

The disk is described by Meek as ‘‘depressed, nearly circular, showing on the dorsal side ten
ovate-subtrigonal radial plates, that are jomed together over the inner ends of the arms, so as to
form five pairs.” A close examination of the specimen shows that the disk is made up of numer-
ous small imbricating plates, and that the supposed division into ten mentioned by Meek may
be explained by the fractured condition of the poorly preserved specimen.

The arms are small and are, as stated by Meek, perhaps three-fourths of an inch in length,
although none of them are preserved entire. The upper-arm plates are wider than long and
hexagonal inform. The outer angles are sharp and are embraced between the upper portions
of the side plates. The latter are shghtly swollen but are not shown in their entire length. The
lower arms are poorly preserved but so far as exhibited are long and narrow, nearly rectangular
in shape, and slightly swollen in their central portions.

Related forms.—Some doubt exists as to the generic position of this species. So many of the
distinctive characters are wanting that a definite determination is quite impossible, but from the
apparent structure of the disk, formed of numerous imbricating plates, its reference to Ophiogly-
phaseems probable. The only other form, O. texana, has, so far as can be discerned, a somewhat
smaller and differently constructed disk, and both the upper and under arm plates are of different
shape.

Locality.—The “last foot of Bridger Peak, 4 miles north of Fort Ellis, Mont.’”’ (Meek).

Geologic horizon.—Associated with species of the genera Gryphea, Avicula, Inoceramus,
Crassatella, Pholadomya, Turritella, and Gyrodes, that denote the Cretaceous age of the strata
(Meek). Upper Cretaceous, most probably Colorado shale.

Collection.—U.S. National Museum (7820).

Class ECHINOIDEA.
Subclass REGULARIA ENDOBRANCHIATA.
Order CIDAROIDEA.
Family CIDARID.
Genus CIDARIS Leske.
CiDARIS TEHAMAENSIS Clark, n. sp.
Plate IX, figure 1.

Determinative characters.—Test unknown. Spines large and club-shabed, with rows of
granules extending from neck to point of spine.

Dimensions.—Spine: Length 30 millimeters; width in thickest part 12 millimeters.

Description.—This species is represented by a well-preserved spine that is large and club-
shaped. The granules are large and disposed in rows extending from the neck to the point of
the spine.

Locality.—Shelton’s ranch, Tehama County, Cal.

Geologic horizon.—Knoxville formation, Lower Cretaceous.

Collection.—U. S. National Museum (31195).

CRETACEOUS ECHINODERMATA. 45
CipaRIs TEXANUS Clark.
Plate IX, figures 2a-f.
Cidaris texanus Clark, 1891, Johns Hopkins Uniy. Cire., vol. 10, No. 87, p. 75.

Cidaris texanus Clark, 1893, Johns Hopkins Uniy. Cire., vol. 12, No. 103, p. 61.
Cidaris tecanus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 36, 37, Pl. VII, figs. la-e.

Determinatwe characters.—Test large, inflated. Ambulacra narrow, sinuous, with four rows
of granules between the poriferous avenues, which at the ambitus are increased to six and toward
the apical system and peristome are reduced to two rows. Pores oval, separated by transverse
elevations, which partially envelop the openings. Interambulacra wide, with large circular
tubercles. Areola circular, depressed; boss smooth; mamelon small, perforated. Miliary space
wide, covered with numerous small granules.

Dimensions.—Diameter 80 millimeters (?); height 40 millimeters (?).

Description.—A large portion of the test of this beautiful species is excellently preserved.
All of the characteristic features, except those relating to the apical system and peristome,
are clearly shown. The test, however, is somewhat compressed, so that the original form can
not be made out with certainty. The ambulacral areas are narrow and slightly flexuous.
Between the poriferous avenues, which are narrow and depressed, are four rows of granules of
nearly equal size, which directly at the ambitus are increased to six, and toward both apical
system and peristome are reduced to two. Irregularly scattered among the rows of granules
are others smaller in size. The pores are oval and separated by transverse elevations that
partly encircle the openings, leaving a depression between each pair.

The interambulacral plates are wide and bear large circular tubercles. The areola of each
tubercle is radially ridged, deeply depressed, and surrounded by a row of mammillated granules.
The boss is slightly elevated above the level of the plate and presents a smooth and sharp ridge
around the small perforated mamelon. The miliary space is wide and thickly set, with small
elevated granules of equal size. The apical system and peristome are lacking.

Related forms.—At first sight the species shows strong points of similarity to C. sceptrifera
Mantell from the White Chalk of England, although the arrangement of granules in its ambula-
cra is different. The areola of C. sceptrifera is described as smooth, and that of C. texanus as
clearly ridged radially. The only related form reported from Texas is Leiocidaris hemigranosus,
formerly referred to Cidaris, but which, as will be shown, does not belong to that genus. Cida-
ris branneri, from Brazil, described by White, is allied to C. texanus, but differs from it in the
character of the areola and the arrangement of granules in both the ambulacral and interam-
bulacral areas.

Locality — Bexar County, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collection.—U.S. National Museum (8381).

' Ciparis waLcorrt Clark.
Plate IX, figures 3a-d.

Cidaris walcotti Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.

Cidaris walcotti Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Cidaris walcotti Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 37, 38, Pl. VI, figs. 4a-d.

Cidaris walcotti Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.

Cidaris walcotti Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 281-282, Pl. VII,
figs. 10-13.

Determinative characters —Test small, inflated. Ambulacral areas narrow, sinuous, with
four rows of granules between the depressed poriferous avenues. Interambulacral areas broad;
each tubercle with depressed circular areola, smooth boss and small imperforate mamelon.
Miliary space wide, thickly covered with small granules.

Dimensions.—Type specimen: Height about 25 millimeters; width about 37.5 millimeters.

89800°—15——4

46 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Description —The fragments of this form examined are sufficiently distinctive to separate
it from other species. A nearly complete interambulacrum with the adjoming ambulacra
shows that the test of the species is small and in a marked degree inflated.

The ambulacra are narrow, slightly sinuous, and provided with four nearly equal rows of
granules between the poriferous avenues. On some additional granules are irregularly inter-
spersed. The poriferous avenues themselves are narrow, deeply depressed, and slightly sinuous.
The pores are round, with funnel-shaped openings, produced by the intersecting ridges. These
ridges, which separate the individual pores and the pore pairs, give a lattice-like appearance to
the poriferous zones.

The interambulacral plates are moderately large. On account of the indistinctly marked
sutures the small tubercles and numerous granules cause a very even surface over the entire
interambulacrum. The tubercles are circular and stand nearer the outer margin of the plates
than the inner. The areolas are deeply depressed, the central portion but shghtly exceeding the
margin in height. The boss is smooth and stands but little above the level of the plate. The
mamelon is imperforate. The wide miliary space is covered with a large number of irregularly
arranged granules of equal size. The broken specimens afford no information as to the character
of the apical system or peristome.

Related forms.—The species is very readily separated from C. splendens, the only other
representative of this genus thus far reported from the Atlantic coast Cretaceous, by its pos-
session of imperforate mamelons and wide miliary spaces, over which the granules are regularly
scattered. The even surface of the test is likewise a distinguishing feature.

Localities —Timber Creek.(type) and Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia (1451); Johns Hopkins University.

CIDARIS SPLENDENS Morton.
Plate IX, figures 4a—b, 5a-f, 6.

Cidaris (?) sp. Morton, 1829, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, p. 123.

Echinus sp. Morton, 1830, Am. Jour. Sci., 1st ser., vol. 17, p. 287; vol. 18, Pl. III, figs. 12, 13.
Cidarites splendeus ! Morton, 1841, Acad. Nat. Sci. Philadelphia Proc., vol. 1, p. 132.

Cidarites armiger Morton, 1842, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 8, p. 215, Pl. II, fig. 1
Cidaris armiger Gabb, 1859, Cat. Invert. Fossils Cretaceous formation, p. 18.

Cidaris splendens Gabb, 1859, Cat. Invert. Fossils Cretaceous formation, p. 18.

Cidaris armigera Agassiz, 1874, Revision of the Echini, p. 751.

Cidaris armiger Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.

Cidaris splendens Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Cidaris splendens Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 33-35, Pl. VI, figs. 3a-g.

Cidaris splendens Johnson, Acad. Nat. Sci. Philadelphia Peas vol. 57, p. 6.

Cidaris splendens Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 279-281.

Determinative characters—Test of moderate size, spheroidal. Ambulacral areas narrow,
flexuous, with four rows of granules between the pore pairs, the outer rows larger than the inner;
imperfectly defined granules also appear between the pores of each pair. Interambulacral areas
very wide, with seven or eight plates in each column, each plate bearing a tubercle of large size
characterized by a wide circular areola, smooth boss, and small perforated mamelon. Miliary
area small and covered with numerous thickly set granules of small size. Sutures sharply
defined, depressed. Spines elongated, cylindrical, with longitudinal rows of sharp denticulated
processes.

Dimensions.—Height 21.9 to 23 millimeters; width 34.4 to 40 millimeters.

Description.—The first mention of this form is made by Morton in 1829, when he doubtfully
referred a few fragments to Cidaris without an attempt at specific determination. Several of the
more important characters were then given, but as the material examined included only detached
plates and a few spines the description necessarily lacked much of completeness. In 1841 he
proposed the name Cidarites splendens and then more accurately defined the species. In 1842

1 Morton doubtless intended to use the term splendens instead of splendeus, which is probably a typographic error. In the publication of
_ 1842, where armiger is substituted, the form splerdens is used.

CRETACEOUS ECHINODERMATA. AT

he redescribed and now for the first time figured the same form as Cidarites armiger, a name which
he stated he desired substituted for C. splendens. Gabb in 1859 employed both names, mistaking
them for independent species, but refers to C. splendens as C. splendeus. The specimens exam-
ined by the writer were chiefly detached plates, although one nearly complete test and two entire
or nearly entire interambulacral areas, with parts or all of the adjoining ambulacra, were also
among this material. In these specimens the oral side is slightly more depressed than the aboral,
although not to the extent exhibited in Morton’s figure. The ambulacral areas, which are nar-
row and flexuous, have, between the poriferous avenues, four granules. In the center of each
column of plates these granules are approximately of equal size, the outer rows slightly larger,
but toward the disk or toward the peristome the inner rows abruptly diminish in size and finally
disappear. The pores are oval in shape with funnel-like openings exteriorly. Each row of
pores is separated from that which accompanies it in the same avenue by a row of imperfectly
defined granules that form an undulating ridge.

The interambulacral areas are very wide and bear large tubercles, each of which covers
the greater portion of its plate. Upon the larger plates, in the center of each column, the
areolas are circular, but become somewhat oval toward both disk and peristome. The outer
edge of each areola is surrounded by a circle of large granules that give it a crenulated appearance.
The areola rises from its depressed margin, gradually at first, then rapidly, to the boss, which
reaches a marked elevation above the general level of the plate. The boss is of moderate width
and smooth. From its center rises the mamelon, which is small, perforated, and slightly
flattened upon the upper surface. The miliary space is covered by small granules, which are
most numerously developed along the median line of the interambulacra.

None of the specimens affords the apical system. Strong auricule show the presence of
powerful jaws.

The spines are slender, elongated, cylindrical, with longitudinal, serrated ribs that gradually
become obsolete toward the base. The collar is short and finely striated longitudinally. The
acetabulum is bordered by a smooth margin and is perforated in the center.

Related forms.—In many particulars Cidaris splendens (Morton) resembles C. serrata Desor»
of the European Cretaceous, but differs from it in several others notably in having only four
rows of granules between the poriferous avenues.

Localities.—Timber Creek (type) and Vincentown (figured specimens), N. J.

Geologic herizon.— Vincentown sand of the Rancocas group, Upper Cretaceous.

Collections.—Philadelphia Academy of Natural Sciences; Johns Hopkins University
(T3002).

CIDARIS DIXIENSIS Cragin.

Plate IX, figures 7a—b.
Cidaris dixiensis Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 146. Pl. XLVI, figs. 15, 16.
Determinative characters.—Cragin says:

Test rather small, thin; tubercles perforate, not crenulate, rather small and feebly elevated; areolse feebly depressed;

¥

interambulacral plates ornamented with crowded rounded granules which increase in size (in the smaller plates, grad-
ually) toward the areola, the largest granules forming an alternating double row around it.

Dimensions.—Height of terambulacral plates 6 to 7 millimeters; width 7 to 8 millimeters.

Description.—The isolated interambulacral plates, which are the only portions of the test
known, indicate that the form was not in all probability a large one. The tubercles are but
slightly elevated, and the areole are feebly depressed. The mamelon is small and perforated.
The boss is smooth. The miliary space is relatively narrow, covered with granules larger toward
the areola, where they form an alternating double row around it.

Related forms.—The characters given separate this species from all of the American species with which the writer
is acquainted. In the facies of the interambulacral portion of the test, it bears considerable resemblance to C. sé rrifer
Forbes, from which it differs in the form of the plates.

Locality.—Nine miles northeast of Dallas, Tex.

Geologic horizon.—Taylor marl, Upper Cretaceous.
Collection.—Geological Survey of Texas.

48 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

? CIDARIS NAHALAKENSIS De Loriol.

Cidaris nahalakensis De Loriol, 1887, Recueil zool. Suisse, vol. 4, pp. 388, 389, Pl. XVII, figs. 3-4.
?Cidaris nahalakensis Clark, 1893, U. S. Geol. Survey Bull. 97, p. 93.

The species is based by P. de Loriol on fragments of spines obtained from the Selma chalk
(‘Rotten limestone”’) of the Upper Cretaceous of Wahalak, Kemper County, Miss. Similar
spines have been recognized by the writer from other localities, but whether they represent an
independent species or one hitherto described is not clear.

Genus LEIOCIDARIS Desor.
LEIOCIDARIS HEMIGRANOSUS (Shumard).
Plate X, figures la-g; Plate XI, figures la—b.

Cidaris hemigranosus Shumard, 1860, St. Louis Acad. Sci. Trans., vol. 1, p. 609.
Cidaris hemigranosus Meek, 1864, Smithsonian Mise. Coll., vol. 7 (177), p. 2.
Cidaris hemigranosus White, 1883, U. 8. Geol. and Geog. Survey Terr. Twelith Ann. Rept., for 1878, p. 38, Pl, XVIII,

figs. 2a-b.
Leiocidaris hemigranosus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.
Leiocidaris hemigranosus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 38, 39, Pl. VII, figs. 2a-d; Pl. VIII. figs. la—b;

Pl. 1X, figs. lac.

Leiocidaris hemigranosa Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 160, Pl. XLVI, fig. 4.
Leiocidaris hemigranosus Hill, 1901, U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, pp. 252, 266, 272.

Determinative characters—Test very large, subspherical. Ambulacra narrow, sinuous,
with six rows of granules in the middle. Poriferous avenues, wide, deeply depressed. Pores
of each pair united by clearly defined furrow. Interambulacra broad. Tubercles very large;
areola circular or slightly polygonal, depressed; boss smooth, mamelon large, perforated.
Miliary space covered with large scattered oval granules. Sutures clearly marked, depressed.

Dimensions.—Diameter 90 millimeters; height 67 millimeters.

Description—The form, which was quite fully described by Shumard in 1860, but not
‘ficured, was incorrectly referred to the genus Cidaris, from which it is separated by the presence
of furrows uniting the pores of each pair. In this respect it is a typical representative of the
genus Leiocidaris of Desor. A very good illustration was given by White in 1883 (report for
1878), although necessarily, from the size of the figure, the furrows connecting the pores could
not be very distinctly shown. This species is the largest echinoid known from the Texas Cre-
taceous, and with possibly a single exception the largest from the American Mesozoic. In one
unusually fine specimen the test is subspherical, although considerably broader and more flat-
tened-on the oral than aboral side.

The ambulacra are narrow and sinuous, with six rows of granules between the poriferous
avenues. The regular arrangement of the granules is not persistent, the number being increased
irregularly near the middle of the column and somewhat reduced toward the apical system and
peristome. The poriferous avenues are wide and deeply depressed, the pores of each pair being
united by a shallow furrow.

The interambulacra are wide and the plates of massive size. The tubercles occupy the
center of the plates and are large and prominent. The areolas are deeply depressed, subcir-
cular or slightly polygonal, and occupy more than half of the greatest diameter of the plates.
On all the specimens examined the areolas show perfectly smooth surfaces, although Shumard
mentions the occurrence of radiating ridges. Toward the center each areola rises to form the
boss, which is provided marginally with a sharp smooth ridge. The mamelon is large, sub-
spherical, with a deep perforation uponits summit. The miliary space is wide and covered with
large, irregularly shaped and flattened granules, some round and some oval in form. Inter-
spersed among these are much smaller granules, which increase in number along the margin of
the plates. The apical system and peristome are wanting.

Related forms.—The species is readily separated from any hitherto described from American
or European strata. Its characters are well defined and distinctive.

CRETACEOUS ECHINODERMATA, 49

Localities.—Upper part of the bluff of Red River, Lamar County, and 10 miles above the
mouth of Kiamesha Creek (type); 3 miles west of Denison (figured specimen); railroad cut
west of Austin; and ‘‘Gap,”’ Travis County, Tex.

Geologic horizon.—Denison formation of Washita group, Comanche series, Cretaceous.

Collection.—U. S. National Museum (21768).

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder CALYCINA.

Family SALENIID®.

Genus SALENIA Gray.

SALENIA TEXANA Credner.

Plate XII, figures la-i; Plate XIV, figures la-c.

Cidaris diatretum Giebel, 1853, Naturwiss. Ver. in Halle Jahresb. for 1852, p. 374, Pl. VII, figure 2.
Salenia tecana Credner, 1875, Zeitschr. fiir gesam. Naturwiss., vol. 46, pp. 105-116, Pl. V, figs. 1-6.
Salenia texana Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.

Salenia texana Clark, 1893, Johns Hopkins Uniy. Circ., vol. 12, No. 103, p. 51.

Salenia texana Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 40, 41, Pl. X, figs. la-h.

Salenia texana Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 163, 164.

Determinative characters—Test subglobose; upper surface convex; sides inflated; under
surface flat. Ambulacra narrow, flexuous, with two rows of mammillated granules in each area;
poriferous zones flexed; pores uniserial. Interambulacra wide, with two rows of alternating
plates, six in each row. Apical system large, convex, subcircular; periproct prominent. Peri-
stome moderately large.

Dimensions.—Diameter 10 to 25 millimeters; height 7 to 20 millimeters.

Description.—Credner presents the first complete diagnosis of a North American Mesozoic
echinoid in the detailed descriptions accorded the present species. Its reference by Giebel in
1852 to Oidaris diatretum (= Pseudodiadema diatretum) was erroneous.

The test is subspherical when complete, but in many of the specimens examined is somewhat.
flattened, both actinally and abactinally. The lower surface is slightly concave in the vicinity
of the peristome. The sides are inflated, presenting a rounded surface which is fuller above
than below.

The ambulacra are narrow, increasing gradually in width from the apical system to the
peristome. Two rows of mammillated granules, twenty-four to twenty-six in each, occupy, the
middle of each area. Very minute granules extend in a line between the rows and in the vicinity
of the peristome surround the larger granules themselves. The poriferous zones are narrow and
flexuous, and the pores are regularly arranged in a uniserial series; near the peristome they are
slightly more crowded. The most pronounced flexure is opposite the second interambulacral
plate from the apical system. Toward the peristome the zones become nearly straight.

The interambulacra are broad and formed of two alternating rows of broad plates, six in
each row. The tubercles increase rapidly in size from the peristome, where they are scarcely
larger than the mammillated granules of the ambulacra. The areolas are large and surrounded
by mammillated granules of various sizes that are crowded together along the inner edge of the
plates. Between the larger granules are numerous minute granules. The areola rises to a prom-
inent boss that is deeply crenulated and bears an imperforate mamelon.

The apical system is very large, convex, subcircular, with radiating ridges that extend from
the ovarial openings of each plate and unite with similar ridges of adjacent plates. Small punc-
tures are found at the angles of the plates and intermediate between them. The subanal plate

50 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

is situated before the periproct and occupies the center of the disk. The periproct is subellipti-
cal, rounded anteriorly, angular posteriorly, and slightly elevated at the border.

The adoral surface is flat and the peristome large, covering nearly one-half the diameter of
the test. The peristome is circular, with ten incisions upon the edge that divide it into nearly
equal sized lobes.

Related forms.—Credner in discussing the affinities of this form considers it to be closely
related to Salenia petalifera Defrance and S. desori Wright. It is somewhat more elevated than
S. petalifera, the radial ridges on its apical system are more pronounced, and its ocular plates
enter more compactly into the composition of its disk. From S. desori, on the other hand, it
differs more widely, both in the character of the test plates and the decorations of the apical
system. With S. scutigera Gray it shows some points in common.

Localities. —Cileola, Comanche spring (figured specimen A); Bosque County (figured speci-
men B); 24 miles north of Denison; 5 miles west of Kent; Bexar County; Round Rock ; Wil
liamson County, Tex.

Geologie horizon.—Fredericksburg and Washita groups of the Comanche series, Cretaceous.

Collections —U. S. National Museum (8329, A); Boston Society of Natural History; Johns
Hopkins University (T3003, B).

SALENIA TUMIDULA Clark.
Plate XIII, figures la-j.

Salenia twmidula Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.

Salenia tumidula Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Salenia tumidula Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 41, 42, Pl. XI, figs. 1a-j.

Salenia twmidula Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.

Salenia tumidula Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 282, 283, Pl. VIIT,
figs. 1-10. ;

Determinative characters.—Test small, subglobose; outline of upper surface regularly convex.
Ambulacra narrow, nearly straight, with two rows of mammillated granules between the pore
pairs; poriferous zones slightly flexed; pores uniserial. Interambulacra wide, composed of two
alternating rows of five or six plates. Apical system large, regularly convex, subcircular;
periproct slightly elevated. Peristome small.

Dimensions.—Diameter 2 to 13 millimeters; height 1 to 10 millimeters.

Description.—The perfectly preserved specimens of this beautiful species permit determi-
nation of all the details of structure.

The general form of the test is subglobose. The sides are inflated and regularly curved,
rising into a convex upper surface, from which the periproct projects but slightly. The lower
surface is almost flat and toward the peristome is slightly depressed.

The ambulacra are rather broad, increasing in width from the apical system to the peristome.
Extending along the center of each area are two rows of mammillated granules, 15 or 16 in each
row, between which are other minute granules. The poriferous zones are narrow and nearly
straight; the pores round, regularly arranged in a uniserial series, and largest in the middle
of the column.

The interambulacra consist of two rows of alternating plates, five or six in each row. The
larger tubercles diminish rapidly in size toward the mouth edges, and are very indistinct on the
plates bordering thesame. Each areola is large and circular, the boss crenulated, and the mame-
lon flattened and imperforate. The miliary space is bordered with oval granules of irregular size
and arrangement, although most numerous between the rows of tubercles. The sutures of the
plates are very indistinctly marked.

The apical system is prominent, subcircular, with a regularly curved convex surface, from
which the anal aperture projects but shghtly. The granular decorations of the surface often
coalesce and appear as broken ridges extending radially from the five openings in the genital
plates. The periproct is oval, slightly pointed below, and projects but slightly above the level
of the apical system. It is bordered by a flangelike edge that is formed of the anal and two
genital plates.

CRETACEOUS ECHINODERMATA., 51

The peristome is small, occupying scarcely two-fifths of the diameter of the test. Ten
incisions divide the edge into lobes, the ambulacral lobes projecting the farther.

Related forms. —The identity of this species is readily established by the straight poriferous
zones and peculiar decorations of the apical system. The number of mammillated granules in
the ambulacral areas is less than in S. texana, and the oval granules of the interambulacral areas
are readily distinguishable from the round forms of S. bellula. The periproct also projects far
less than in S. texana, although in this respect it is not unlike S. bellula.

Lovely tna Co near Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections. —Academy of Natural Sciences of Philadelphia (1448) ; Johns Hopkins University.

SALENIA BELLULA Clark.

Plate XIII, figures 2a-g.

Salenia bellula Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.

Salenia bellula Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Salenia bellula Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 43, 44, Pl. XI, ae 2a-g.

Salenia bellula Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6

Salenia bellula Weller, 1907, Ohana paleontology of New iowa Geol! Sn New Jersey, pp. 283-284, Pl. VIII,
figs. 11-17.

Determinative characters —Test small, compressed, circular; upper surface convex; sides
inflated; under surface flat. Ambulacra ahr broad, nearly sianieht, with two rows of gran-
ules in each row; poriferous zones broad, very slightly flexed; pores avin, uniserial. ners am-
bulacra wide. Astor system convex aval nearly circular. PRamisthonan sill

Dimensions.—Diameter 6 to 8 millimeters; height 10 to 13 millimeters.

Description.—This Salenia is a very rare form, only a few specimens having come under the
notice of the writer. Certain peculiarities of outline and structure prevent its being confounded
with other species heretofore described.

In general outline the test is somewhat flattened; the upper surface is regularly convex; the
sides are inflated; the lower surface is flat or slightly concave at the peristome.

The svealorellnonn are prominent and change but slightly in width from the apical system to
the peristome. Two rows of mammillated granules, 15 in each, occupy the center of each
area.

The interambulacra are wide and consist of two rows of alternating plates, five or six in
each. The tubercles are prominent, but decrease rapidly in size, the boss narrow and indistinctly
crenulated, and the mammalon small, flattened, and imperforate. An indistinct circle of mam-
millated granules surrounds each tubercle. They unite to form a sinuous double series between
the rows of tubercles. Between the larger granules are scattered irregularly numerous small
granules that are crowded together along the central line of the interambulacra.

The apical system is slightly convex, the periproct interfering but little with the regularity
of the curved surface. The periproct is subcircular, with a flangelike rim. The plates are
decorated with oval granules arranged in radial rows extending from the opening of each genital
plate and unite with corresponding rows of adjacent plates at the suture.

The peristome is small, being one-third of the transverse diameter of the test. Ten weak
incisions divide the edge into lobes that are nearly of equal size.

Related forms.—This species is quite distinct from Salenia texana or 8. tumidula, and at the
same time does not admit of reference to any of the European species. It is most closely related
to S. tumidula, but is more compressed, has a differently shaped and decorated apicalsystem, and
has round and mammillated granules in the miliary space, whereas those of 8. tumidula are char-
acteristically oval.

Locality —Timber Creek, near Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections —Academy of Natural Sciences of Philadelphia (1446); American Museum of
Natural History, New York.

52 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Suborder ARBACINA.
Family HEMICIDARID&.
Genus HYPODIADEMA Desor.
HyYpopiaADEMA ELEGANS Clark, n. sp.
Plate XIV, figures 2a-b.

Determinative characters —Test small, moderately inflated, slightly tumid above the ambitus.
Ambulacra narrow, nearly straight, with small perforate, crenulate tubercles diminishing in size
from the ambitus aborally. Interambulacra broad, with moderately large tubercles perforate
and crenulate. Apical system prominent, genital plates large, forming a periproctal ring; ocular
plates small, elevated.

Dimensions.—Diameter 13.5 millimeters.

Description.—Only a single specimen of this species has been found. The abactinal and
central portions of the test are well preserved, but the actinal surfaceis covered. The delicately
sculptured test is small, somewhat inflated above. The ambulacra are nearly straight and nar-
row. Thesmall primary tubercles at the ambitus are perforate and crenulate, but diminish in size
toward the apical system.

The interambulacra are broad, the primary turbercles large, crenulate, and perforate, the
depressed areolas being surrounded by a circle of granules. The miliary space is narrow, except
toward the apical system, where it is large on the abutting plates. The apical system is elevated
and pronounced. The large genitals which form the periproctal ring are perforated, the madre-
porite having two large openings. The oculars are small and elevated.

Locality Junction of Muddy and Clear forks of Little Missouri River, 3 miles west of Mur-
freesboro, Pike County, Ark.

Geologic horizon.—Trinity sand of the Comanche series, Cretaceous.

Collection.—U. 8. National Museum (31196). -

Genus GONIOPYGUS Agassiz.

GONIOPYGUS ZITTELI Clark.

Plate XIV, figures 3a-c; Plate XV, figures la-h.

Goniopygus zittelli Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.

Goniopygus zittelli Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.

Goniopygus zittelli Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 53, 54, Pl. XVIII, figs. 2a-d; Pl. XTX, figs. la-e.
Goniopygus zitteli Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 155.

Determinative characters.—Test subconical, circular in outline; upper surface elevated; base
flattened. Ambulacra broad, with a double row of alternating tubercles, 18 to 20 in each series;
poriferous zones, with a double row of pores, multiplied at the peristome. Interambulacra
broader than the ambulacra, with a double. row of primary tubercles, 10 to 12 in each row.
Apical system prominent, compact. Peristome large, with shallow incisions.

Dimensions —Diameter 25 to 38 millimeters; height 15 to 25 millimeters.

Description.—All specimens examined by the writer have a distinctly subconical form that is
highly characteristic. The upper surface is very much elevated, while the lower is flat and
slightly depressed around the peristome.

The ambulacra are broad, increasing regularly in width from the apical disk to the ambitus,
beyond which they decrease toward the peristome. There is a double row of 18 to 20
tubercles in each area that rapidly increase in size from the apical system downward. ‘The pores
are arranged in a double row on each poriferous zone, except in the vicinity of the peristome, where
they become suddenly increased in number.

The interambulacra are about one and one-half times the width of the ambulacra, and each
contains a double row of large tubercles, 10 to 12 ineach series. _These tubercles are con-
siderably larger than those of the ambulacral area, and have wide circular areolas, smooth bosses,
and imperforate mamelons. On the base the tubercles of all the areas are of nearly equal size.

CRETACEOUS ECHINODERMATA, 53

The miliary space is wide, very nearly smooth in the upper portions of the column, and sparsely
covered with granules toward the peristome.

The apical system is large and compact, the elongated genital plates giving it a star-shaped
appearance. The well-defined ocular plates, wedged into the interspaces, make the entire out-
line subpentagonal. Each genital plate is angular at the outer extremity and perforated. On
the inner edge of the same there is a semicircular depression, in the center of which is a small
mammillated tubercle.

The peristome is large, covering quite one-half the diameter of the base. It is divided into
ten lobes by ten shallow incisions.

Related forms.—The species shows many points of similarity to Echinus patagonensis,
described by D’Orbigny in 1842, from the Tertiary of southern Patagonia. The margin of
D’Orbigny’s species is sharper and its apical system of somewhat different shape; moreover, if
properly referred to the Tertiary, it is undoubtedly a different form. Echinus andinus, from the
desert of Atacama, described by Philippi in 1860, is likewise closely allied to G@. zitteli, although
more conical and presenting a different surface decoration of the plates. Goniopygus major,
from the Cenomanian of Europe, is similar in many particulars, although the pores are not
increased around its peristome as in @. zitteli, and its apical system is more compact.

Locality.—Round Rock (type) and Spenish Oak branch, Williamson County, Tex.

Geologie horizon.—Edwards limestone of Fredericksburg group, Comanche series, Cretaceous.

Collections.—U. S. National Museum (12234); Texas Geological Survey.

Genus LEPTARBAOIA Clark, n. gen.

Test small, circular in ambital outline, subhemispherical, upper surface depressed, lower
surface flat. Ambulacral plates are simple primaries near the apical system and compound at
the ambitus. Compound plates consist largely of one primary and three demiplates, two above
and one below. Interambulacra with large plates and with six rows of small perforated and
crenulated tubercles on lower surface which become reduced. Peristome of medium size.
Periproct small. .

LEPTARBACIA ARGUTUS Clark, n. sp.
Plate XVI, figures la-f.

Determinative characters.—Test small, depressed above, flat below, apical system of medium
size, periproct nearly circular. Ambulacra straight, rather wide at ambitus and on lower sur-
face, plates compound except near apical system, generally composed of one primary and three
demiplates, some plates with one primary and two demiplates. Interambulacra with long bare
median areas on upper surface, approaching ambitus, and on lower surface six rows of small per-
forated and crenulated tubercles.

Dimensions.—Diameter 20 millimeters; height 12 millimeters.

Description.—The single specimen of this species is small, with depressed upper surface
and nearly flat below. It is somewhat depressed near the peristome.

The ambulacra are narrow, increasing in width from the apical system to the ambitus,
beyond which they decrease in width toward the peristome. There is a double row of about
thirty tubercles in each area, which become quite indistinct toward the apical disk. The pores
are arranged in an irregular simple series in each poriferous zone.

The interambulacra are about three times the width of the ambulacra, and each contains
from the ambitus to the peristome six rows of smail perforated and crenulated tubercles, the
central row of tubercles of each half continuing to the apical system, although gradually becoming
less distinct as the latter is approached. The miliary space is covered with small granules.

The apical system is small, the genital plates being somewhat larger than the ocular, but
rarely projecting farther than the latter. The periproct is small and slightly subcentral.

The peristome is apparently of medium size but is not well enough preserved to show its
characteristic features.

Locality.—¥ ort Worth, Tex.

Geologic horizon.—W ashita group of the Comanche series, Cretaceous.

CQollection.—Johns Hopkins University (T 3004).

54 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Suborder DIADEMINA.

Family ORTHOPSID®.
Genus ORTHOPSIS Cotteau.
ORTHOPSIS PLANULATA Clark, n. sp.
Plate XVI, figures 2a-c.

Determinative characters.—Test small, depressed, circular in ambital outline, upper surface
flattened, lower surface concave. Ambulacra narrow, pore pairs simple, primary tubercles
small. Interambulacra broad, with several rows of vertical primary tubercles slightly larger
than the ambulacra. Peristome of medium size.

Dimensions.—Diameter 28 to 32 millimeters; height 10 to 12 millimeters.

Description.—The species is represented by two specimens embedded in a single mass of
indurated marl, one showing the adoral and the other the aboral surface, the former containing
a number of spines. The test is relatively small, much depressed, the upper surface being dis-
tinctly flat, except directly at the apical system, which is slightly elevated. The under surface
is concave. The ambulacra are narrow and bear two rows of small perforate, uncrenulated
tubercles that become indistinct toward the apical system. The plates are simple primaries on
the upper surface, but from just above the ambitus to the peristome two of the primaries com-
monly combine, the suture passing through the interporiferous tubercle. The poriferous zones
bear a straight uniserial series of pores.

The interambulacra are broad, with six rows of perforate, uncrenulated tubercles on the
under surface which are much reduced on the upper surface.

The peristome is of moderate size.

Locality.—Cut on Bonham road, southeastern edge of Denison, Tex.

Geologic horizon.—Grayson marl member of the Denison formation, of Washita group,
Comanche series, Cretaceous.

Collection.—Johns Hopkins University (T 3005).

ORTHOPSIS .OCCIDENTALIS Cragin.
Plate XVII, figures la-g.

Orthopsis occidentalis Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 160, 161, Pls. XXV, figs. 1-3; X XVII,
fig. 2. :

Determinative characters.—Test large, depressed, slightly pentagonal in ambital outline,
upper surface tumid, lower surface concave; five perforated genitals, one a large madreporite,
some of the oculars reaching the periproctal margin. Ambulacra narrow, straight; pore pairs
in simple, straight series; primary tubercles small, perforate, and smooth; interambulacra broad
with several vertical rows of small primary tubercles similar to the ambulacra. Peristome of
medium size.

Dimensions.— Diameter 57 millimeters; height 33 millimeters.

Description.—The test is large, somewhat depressed, and slightly pentagonal in ambital
outline. The upper surface is tumid directly above the ambitus, while tae lower surface is con-
cave.

The ambulacra are very narrow. Two rows of small primary perforated and uncrenulated
tubercles extend from the peristome to the apical disk. The plates are sumple primaries on the
upper surface, but from the ambitus to the peristome two of the primaries generally combine, the
suture passing through the interporiferous tubercle. The pores occur in simple series in the
narrow poriferous zones.

The interambulacra are much broader than the ambulacra, with six rows of primary tubercles
similar to those in the ambulacra. All of the tubercles about equal in size below the ambitus
but all except the middle series of each row of plates gradually disappear above the ambitus, the
latter alone continuing to the apical disk.

CRETACEOUS ECHINODERMATA. 55

The peristome is of medium size with moderately developed incisions. The periproct is
relatively large, the plates of the apical system being narrow.

Locahty.—Sierra Blanca Mountain, near El Paso, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collection.—Geological Survey of Texas.

Family DIADEMATID®.
Genus PSEUDODIADEMA Desor.

PSEUDODIADEMA TEXANUM (Roemer).
Plate XVIII, figures la-i.

Diadema tecanum Roemer, 1852, Die Kreidebildungen yon Texas, p. 82, Pl. X, fig. 5.

Pseudodiadema texanwm Desor, 1858, Synopsis des échinides fossiles, p. 72.

Diadema texanum Gabb, 1859, Catalogue of invertebrate fossils of the Cretaceous formation, p. 19.

Pseudodiadema texanum Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2

Pseudodiadema roemeri Clark, 1891, Johns Hopkins Uniy. Cire., vel. 10, No. 87, p. 75.

Pseudodiadema texanum Clark,*1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Pseudodiadema texanum Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 47, 48, Pls. XIII, figs. 2a-n; XIV, figs. la-g.
Pseudodiadema texanum Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 161, 162.

Pseudodiadema texanum Hill and Vaughan, 1898, U.S. Geol. Survey Eighteenth Ann. Rept., pt. 2, Pl. LITI, figs. 3a, 3b.
Pseudodiadema texanum Hill, 1901, U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, Pl. XX VII, figs. 3a, 3b.

Determinative characters.—Test small, circular, depressed; sides inflated; upper and lower
surfaces about equally flattened. Ambulacra narrow, with two rows of primary tubercles, 11
or 12 in each row; poriferous zones narrow, pores uniserial. Interambulacra wide, with
two rows of primary tubercles of larger size than those of the ambulacra. Peristome wide, coy-
ering nearly one-half the diameter br the test. Periproct subcircular, with deep incision in right
anterior ambulacrum.

Dimensions.—Diameter 5 to 12 millimeters; height 8 to 22 millimeters.

Description.—This form, described by Roemer un 1852 as Diadema texanum, was properly
assigned by Desor to the genus Pseudodiadema.

The test is circular, very much depressed on both the upper and lower surfaces and inflated
at the sides.

The ambulacra are narrow and lanceolate. They bear two rows of tubercles, 11 or
12 in each row, that decrease rapidly in size from the ambitus to the poles. The arcolas are
circular, the bosses stout and prominent, the mamelons distinctly perforated. Small secondary
tubercles are irregularly dispersed between the rows of primary tubercles. A few scattered
granules surround the same. The poriferous zones are uniserial throughout, though the pores
show a slight tendency to increase at the peristome.

The interambulacra are about twice the width of the ambulacra. There are two rows of
primary tubercles, 9 or 10 in each row, that decrease in size from the ambitus to the poles.
The areolas are depressed, circular, and distinetly outlined, the bosses elevated and deeply crenu-
lated, the mamelons large and deeply perforated. Small secondary tubercles surround the pri-
mary tubercles, between which are interspersed minute granules.

The peristome is wide, covering nearly one-half of the diameter of the test. Ten incisions
produce well-defined lobes at regular intervals. The periproct is large and subcircular, with a
deep incision in the right anterior ambulacium.

Related forms.—Both Roemer and Desor menticn the similarity of this species to P. tenue,
of the Cenomanian of Europe, from which, however, it is separated by its smaller tubercles and
more numerous granules.

Localities. —Near Fredericksburg and in San Saba Valley (type), Barton Creek between Oat-
manville and Bee Caves (figured specimen), near Austin and many other places in Texas.

Geologic horizon.—Glen Rose limestone of Trinity group and Comanche Peak limestone of
Fredericksburg group, Comanche series, Cretaceous.
Chieu kas S. National Museum (31197); Johns Hopkins University.

56 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

PSEUDODIADEMA DIATRETUM (Morton).
Plate XIX, figures la-t.

Cidaris diatretum Morton, 1833, Am. Jour. Sci., Ist ser., vol. 23, p. 294.

Cidarites diatretum Morton, 1834, Synopsis Organic Remains Cretaceous, p. 75, Pl. X, fig. 10.

Cidaris diatretwum Bronn, 1848, Index palzontologicus, vol. 1, p. 298.

Pseudodiadema diatretwm Desor, 1858, Synopsis des échinides fossiles, p. 73.

Cidaris diatretum Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.

Pseudodiadema diatretum Cotteau, 1862-1867, Paléontologie frangaise, vol. 7, p. 519.

Pseudodiadema diatretum Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.

Pseudodiadema diatretwm Conrad, 1868, Geology of New Jersey, appendix, p. 722.

Cidaris clavigera Credner, 1870, Deutsche geol. Gesell. Zeitschr., vol. 22, p. 218.

Cidaris sceptrifera Credner, 1870, Deutsche geol. Gesell. Zeitschr., vol. 22, p. 218.

Pseudodiadema diatretwm Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 75.

Pseudodiadema diatretum Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.

Pseudodiadema diatretum Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 46, 47, Pl. XIII, figs. la-t.

Pseudodiadema diatretwm Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.

Pseudodiadema diatretwm Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 285-286,
PI. IX, figs. 1-6. .

Determinative characters.—Test circular, convex below, sides inflated. Ambulacra wide,
sinuous, with two rows of tubercles that are large at the ambitus and decrease toward the poles;
primary tubercles and several irregular rows of secondary tubercles. Peristome narrow, about
one-third the diameter of the test.

Dimensions.—Diameter 30 to 37 millimeters; height 12.5 to 15 millimeters.

Description.—The specimens vary greatly in size, the full-grown forms being moderately
large. The sides are inflated.

The ambulacra are wide, slightly raised, and furnished with two rows of tubercles, thirteen
to fourteen in each row. They are large and prominent at the ambitus but decrease gradually
toward the poles. The broad areolas, that are sharply depressed in their marginal portions, are
striated by faint radial ridges on the outer parts. At the upper and inner angle of each plate is
a small secondary tubercle, while irregularly scattered over the other portions of the plates are
smaller tubercles, and between them minute granules. The poriferous zones are slightly flexed,
the pores of each plate being disposed in curved form about the margin. Although*there are
generally three pairs of pores at each plate, four pairs are not infrequent near the ambitus.

The interambulacra are about one and one-half times the width of the ambulacra, and have
two rows of tubercles somewhat larger than those of the latter. There are, in addition, several
irregular rows of secondary tubercles, of various sizes, that are most numerous between the rows
of primary tubercles and the poriferous zones. Sparsely scattered over the interambulacral
space are flattened granules. ;

The primary tubercles of both the ambulacra and interambulacra have wide circular areolas,
elevated and deeply crenulated bosses, and distinctly perforated mamelons.

_ The peristome is narrow, reaching scarcely one-third the diameter of the test. The incisions
of the margin are weak.

The discal opening is subpentagonal.

Related forms.—This species resembles in some particulars Pseudodiadema ornatum Goldfuss
of the Cretaceous of Europe, but the latter form has a different arrangement of the secondary
tubercles and granules and lacks the radial striation upon the areolas.

Localities.—Gloucester (type), Timber Creek, and Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections —Academy of Natural Sciences of Philadelphia (1471); New Jersey Geological
Survey; American Museum of Natural History, New York.

Genus HETERODIADEMA Cotteau.

HETERODIADEMA ORNATUM Clark, n. sp.
Plate XVIII, figures 2a-f.
Determinative characters.—Test small, subconical, ambitus tumid, aboral surface depressed,
lower surface convex; apical opening large; ambulacral plates with two vertical rows of small

CRETACEOUS ECHINODERMATA, 57

perforated and crenulated tubercles, pore pairs in simple series doubling toward the peristome;
interambulacral plates with two rows of primary tubercles but slightly larger than the ambu-
lacral. Peristome small.

Dimensions.—Diameter 23 millimeters; height 11.5 millimeters.

Description.—The single specimen representing this species is small, subconical, depressed
on the aboral surface but tumid at the ambitus. It is apparently distinctly convex on the
adoral surface.

The ambulacra are moderately narrow, with two rows of small, primary, perforate, and
erenulate tubercles. The pore pairs when seen are simple. The plates are compound, the
sutures being very indistinct.

The interambulacra are much wider than the ambulacra and bear two rows of primary
tubercles which are similar to the ambulacral. The posterior interambulacrum is deeply incised
and depressed near the apical system which intrudes far into it.

The large aboral scar indicates an apical system of considerable size.

Locality —Fort Worth, Tex.

Geologic horizon—Washita group of the Comanche series, Cretaceous.

Collection.—Johns Hopkins University (T 3006).

Genus COTTALDIA Desor.

CorraLpra ROTULA Clark, n. sp.
Plate XX, figures la-d.

Determinative characters.—Test small, tumid, subhemispherical, aboral and adoral surfaces
somewhat depressed; apical system small; ambulacral plates crowded with irregular rows of
small primary tubercles, perforate and noncrenulate, pore pairs in simple series. Interambula-
cral plates with numerous small irregularly disposed tubercles; peristome small.

Dimensions.—Diameter 15 millimeters; height 12.5 millimeters.

Description.—The test is small, much inflated at the ambitus, subhemispherical. The
aboral surface is shghtly depressed and the adoral surface more so.

The ambulacra are narrow, with four rows of very small, perforate, and uncrenulate tuber-
cles at the ambitus. The narrow poriferous zones are uniserial. The compound plates are
composed of three primary plates with very indistinct sutures.

The interambulacra are wide, the plates being low and slightly bent. A row of seven small
tubercles crosses each plate nearly horizontally at the ambitus but becomes reduced in number
toward the poles. These tubercles are similar in character to those on the ambulacra.

The apical system and peristome are not preserved on the specimens examined.

Locality —Shoal Creek, Travis County, Tex.

Geologic horizon.—Buda (Shoal Creek) limestone of the Washita group, Comanche series,
Cretaceous.

Collection.—Johns Hopkins University (T 3007); U.S. National Museum.

Genus HEMIPEDINA Wright.
HemrrepINA CHARLTONI Cragin.
Hemipedina charltoni Cragin, 1894, Colorado Coll. Studies, vol. 6, pp. 41, 47, 50, 51.

Description.—Cragin describes this species as follows:

Test small, round-pentagonal, arched above, concave below; apical disk and periproct moderately broad; peris-
tome considerably smaller in proportion to the test than in Pseudodiadema texanum Roemer; pore-belts straight, the pores
somewhat elongated in the direction of the belt, the pore pairs simple throughout and somewhat oblique; ambulacral
are half as broad as the interambulacral, each ornamented with two rows of primary tubercles that are somewhat
smaller than those of the row of largest tubercles on the interambulacral arez, each primary tubercle being subtended
by an irregularly polygonal string of smaller (secondary) ones; interambulacral areze with six rows of primary tubercles,
these being much larger in the middle row of each semiambulacrum than in the others, the primaries subtended by
secondaries for the most part in polygonal strings; surface of test closely granulated in the intervals between tubercles
on both ambulacral and interambulacral arez.

58 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

No figures are given and the incompleteness of the description leave some question as to
whether the reference of this form to Hemipedina is correct.

Dimensions.—Diameter 25 millimeters; height 11 millimeters; width of peristome 7 to 8
millimeters; width of periproct 3.5 millimeters.

Locality —About a mile east of Denison, Grayson County, Tex.

Geologic horizon—Main Street limestone member of the Denison formation of Washita
group, Comanche series, Cretaceous.

Collection.—Baylor University.

Family DIPLOPODIID.

Genus DIPLOPODIA McCoy.
DipLopopiA TAFFI Cragin.
Plate XX, figures 2a-e.
Diplopodia taffi Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 148, 149, Pl. XLVI, fig. 3.

Determinative characters.—Test large, subcireular, depressed; lower surface flattened;
ambulacra with two vertical rows of primary tubercles perforate and crenulate, slightly smaller
than the interambulacral tubercles, pairs of pores biserial above the ambitus toward the apical
system and at the peristome, iniserial below the ambitus; interambulacral plate with eight rows
of primary tubercles at the ambitus; peristome small with well-marked incisions.

Dimensions.—Diameter 59 millimeters; height 26 millimeters.

Description.—This very beautiful species is one of the largest in the Lower Cretaceous. It
is represented by a number of specimens although far less common than Cyphosoma texanum, with
which it is found associated.

The test is depressed and slightly pentagonal in outline. The lower surface is flattened,
the sides somewhat inflated, and the upper surface slightly elevated.

The ambulacra are of moderate width, with two vertical rows of perforate and crenulate
primary tubercles, which are slightly smaller than the mterambulacral tubercles. The pore
pairs are biserial from the ambitus above toward the apical system and at the peristome, but
uniserial from the ambitus toward the peristome.

The interambulacra are broad, with six rows of large and two of small primary tubercles at
the ambitus, the small tubercles, one row on each side outside the large tubercles, being confined
to that region. The outer rows of large tubercles likewise do not reach the peristome and apical
system. A broad and somewhat depressed area follows the median section of the ambulacra.

The apical system is not large and its rays penetrate deeply the interambulacra.

The peristome is small, with ten rather deep branchial incisions.

Related forms.—This species shows some similarity to D. streeruvitzi, but is not quite as
much elevated aborally.

Localities.—North San Gabriel River, 3 miles above Georgetown (type), Benbrook, Tarrant
County, and Blum, Hill County, Tex.

Geologic horizon.—Comanche Peak limestone of Fredericksburg group, Comanche series,
Cretaceous.

Collections.—Geological Survey of Texas; U.S. National Museum.

DIPLOPODIA STREERUVITZI Cragin.
Plate XX, figures 3a-c.
Diplopodia strecruvitzi Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 147, 148, Pl. XXIV, fig. 11, Pl. XXV,

figs. 9-10.

Determinative characters.—Test medium size, subcircular, depressed, upper and lower sur-
faces flattened; ambulacral plates with two vertical rows of primary tubercles, pairs of pores
simple except toward apical system and peristome where they are biserial ; interambulacral plates
with six to eight vertical rows of primary tubercles at the ambitus; peristome small.

Dimensions.—Diameter 25 to 50 millimeters; height 12 to 18 millimeters.

CRETACEOUS ECHINODERMATA. 59

Description.—This species is not numerous, and the known forms are confined to El Paso
County, Tex. The test is very nearly circular in ambital outline, is depressed, and is distinctly
flattened both adorally and aborally.

The ambulacra are of moderate width with two vertical rows of perforate and crenulate
primary tubercles of about the same size as the interambulacral tubercles. The poriferous zones
are wide above the ambitus but narrow at the ambitus and below until near the peristome. The
pore pairs are biserial aborally. There is much crowding of the pore pairs at the peristome.

The interambulacra are wide with six or eight rows of primary tubercles similar to those of
the ambulacra. The outer rows are somewhat irregular in distribution and gradually disappear
aborally.

The apical system is of medium size. The peristome is small.

Localities.—Sierra Blanca peaks (type) and near Kent, El Paso County, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collections.—Geological Survey of Texas; U. S. National Museum.

Family CYPHOSOMATID%.

Genus CYPHOSOMA Agassiz.
CYPHOSOMA HILLI Clark.
Plate XIX, figures 2a-g.
Pseudodiadema hilli Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.
Diplopodia hilli Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Diplopodia hilli Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 50, 51, Pl. XVI, figs. 2a-g.
Diplopodia hilli Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 147.

Determinative characters.—Test subpentagonal, depressed; sides inflated; upper and lower
surfaces flattened. Ambulacra prominent, straight, with two rows of primary tubercles, twelve
or thirteen in each row; poriferous zones narrow, with slight increase in width toward the apical
system; pores in single pairs below but biserial on the upper surface. Interambulacra with two
rows of primary tubercles of equal size with those of the ambulacra. Peristome narrow, circular.
Discal opening broad, pentagonal.

Dimensions.—Diameter 20 millimeters; height 8 millimeters.

Description.—The test has a subpentagonal outline, the projecting ambulacra occupying the
angles. It is depressed on both the upper and lower surfaces, the latter becoming somewhat
concave toward the peristome. The sides are moderately inflated.

The ambulacra are broad, very prominent, and furnished with two rows of large tubercles,
twelve or thirteen in each row, that decrease rapidly from the ambitus toward the apical system
and peristome. The poriferous zones are narrow and lanceolate. The pores are arranged in
single pairs on the lower surface, but from the ambitus to the apical system are increased slightly
in number, and near the apical system become biserial. The interambulacra are narrow and
appear flattened as compared with the slightly projecting ambulacra. They are provided with
two rows of primary tubercles of equal size with those of the ambulacra. There are ten or eleven
ineach row. The areolas are narrow, circular, and elevated, the bosses prominent and distinctly
crenulated, and the mamelons deeply perforated. The tubercles are somewhat widely separated
and the intervening space is covered with small secondary tubercles and sparsely scattered
granules.

The peristome is broad, depressed, and circular. It is divided by ten incisions into well-
defined lobes, those of the ambulacra broader and extending farther into the opening than the
others.

The discal opening is pentagonal, the angles occurring at the point of the medial suture of
the interambulacra.

This species which was earlier referred to Diplopodia has been shown to belong to the genus
Cyphosoma. Better material has furnished specimens in which the morphology of the ambulacra
demiplates can be clearly seen.

60 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Related forms.—The species is not unlike C. tecanwm, from which, however, it is separated by
its smaller size, subpentagonal form, and two instead of four rows of primary tubercles.

Locality.— Austin, Tex.

Geologic horizon.—Austin chalk, Upper Cretaceous.

Collections. —U. S. National Museum (8311); Johns Hopkins University.

CYPHOSOMA TEXANUM Roemer.
Plate XXI, figures la-g.

Diadema texanum Roemer, 1849, Texas, p. 392.
- Cyphosoma texanum Roemer, 1852, Die Kreidebildungen von Texas, p. 82, Pl. X, fig. 6
Cyphosoma texanum Conrad, 1857, in Hall’s U.S. and Mex. Boundary Survey Rept., vol. i, pt. 2, p. 145, PI. I, fig. 3.
Phymosoma tecanum Desor, 1858, Synopsis des échinides fossiles, p. 90.
Cyphosoma teranum Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.
Cyphosoma tecanum Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, p. 276.
Pseudodiadema texanum Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 75.
Diplopodia tecanum Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Diplopodia tecanwm Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 47, 48, Pl. XV, figs. lat; Pl. XVI, figs. la-d.
Cyphosoma texana Aguilera, 1893, Datos para la geologia de Mexico, p- 26.
Diplopodia texana Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 149.
Diplopodia texanwm Cragin, 1894, Colorado Coll. Studies, vol. 5, p. 47.
Cyphosoma texana Aguilera, 1897, Inst. geol. México Bol., Nos. 4, 5, and 6, p. 21.
Diadema texana Bose, 1899, Inst. geol. México Bol., No. 13, p. 11.
Cyphosoma tezana Bése, 1899, Inst. geol. México Bol., No. 13, p. 11.

Determinative characters—Test large, subcircular; sides inflated; upper surface elevated;
lower surface depressed, concave. Ambulacra prominent, with two rows of primary tubercles;
poriferous zones broad above, narrow below; pores uniserial from near peristome to ambitus,
beyond which to the apical system they are biserial. Interambulacra wide, with four rows of
primary tubercles at the ambitus, which become reduced to two at the pores. Peristome wide,
about two-fifths the diameter of the test. Periproct large, subpentagonal.

Dimensions.—Diameter 15 to 20 millimeters; height 8 to 20 millimeters.

Deserv, ption. —This species was first described by Roemer in 1849 as Diadema texanum, but
subsequently, in 1852, was referred to Cyphosoma.

The test is large, ‘auibetirenllan, and elevated. The sides are inflated and the aboral surface
elevated and convex. The base is depressed and concave.

The ambulacra are broad and lanceolate. They have two rows of primary tubercles, four-
teen or fifteen in each series, that are large at the ambitus and decrease gradually toward the
poles. A circle of scattered granules surrounds the narrow areolas. The poriferous zones are
broad upon the upper surface, but below the ambitus are very much narrowed. The pores are
uniserial below the ambitus except directly at the peristome, where they become greatly in-
creased. From the ambitus to the apical system they are biserial.

The interambulacra are about one and one-half times the width of the ambulacral at the
ambitus. There are four rows of primary tubercles at the ambitus which become reduced to two
in the vicinity of the apical system and peristome. In the center of the column the tubercles of
the four rows are of about equal size, but those of the outer rows become much more rapidly
reduced in size toward the poles. Smallsecondary tubercles are found on the outer margin of the
plates, while irregularly scattered granules cover the space between the tubercles. A slight
depression occurs along the line of the median suture. °

The peristome is circular, but is broken by distinct incisions. Its diameter is about two-
fifths that of the test. The periproct is large and subpentagonal.

Thespecies was incorrectly referred earlier by the author to Diplopodia. A more thorough
study of the much better material now available shows that this form is a Cyphosoma.

Related forms.—The species is very closely related to if not identical with C. volanwm of tne
Washita group, but is somewhat taller and its four rows of primary tubercles on each interam-
bulacrum are rather more definitely developed even on small specimens. It also shows a less

CRETACEOUS ECHINODERMATA, 61

subpentagonal ambital outline. If the differences are more than varietal, then (.tezanuwm must
at all events be regarded as the ancestor of C. volanum.

Localities. Fredericksburg and in the San Saba River valley (type), Leon Springs (figured
specimen), near Austin, and many other places in Texas.

Geologie horizon—Comanche Peak limestone cf Fredericksburg group, Comanche series,
Cretaceous.

Collections.—U. 8. National Museum (9838); Boston Society of Natural History; Geologi-
cal Survey of Texas; University of Iowa; Johns Hopkins University.

CYPHOSOMA VOLANUM Cragin.

Plate X XI, figures 2a-b, 3.
Cyphosoma volanuwm Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 147.
Cyphosoma volanum Cragin, 1894, Colorado Coll. Studies, vol. 4, pp. 45, 47.
Cyphosoma volanum Hill, 1901, U.S. Geol. Survey Twenty-first Ann. Rept., pt. 7, p. 283.

Determinative characters.—Test small, subcircular; upper surface slightly elevated; lower
surface depressed, concave. Ambulacra slightly prominent, with two rows of primary tubercles;
poriferous zones sinuous; pores uniserial from peristome nearly to apical system. Inter-
ambulacra wide, each with two rows of primary tubercles, similar to those of ambulacra, adjoin-
ing which are smaller primary or secondary tubercles. Peristome small. Periproct large.

Dimensions.—Diameter 17.5 millimeters; height 8 millimeters.

Description.—This small species has a subcircular test with a slightly elevated upper surface.
In general size and appearance the smaller specimens resemble Pseudodiadema texanum, but
their other characters are very different.

-The ambulacra are broad, with two rows of primary tubercles eight or nine in each row.
The tubercles are large at the ambitus but become very small toward the apical system and peri-
stome. The poriferous zones are narrow on the lower surface and at the ambitus, but widen above.
They aresinuous. The pores are uniserial, although crowded toward the apical system.

The interambulacra are wide. There are two rows of primary tubercles similar to those of
the ambulacra extending from the peristome to the apical system. Additional smaller primary
or secondary tubercles, somewhat irregularly dispersed, adjoin the primary tubercles, while
numerous granules occur on the surface of the plates. :

The peristome is small with distinct branchial incisions. The periproct is large and sub-
pentagonal.

Related forms.—Few if any differences serve to separate this form from C. texanum of the
Fredericksburg group. In general it is lower and more depressed, is rather more subpentagonai
in outline, and the four rows of tubercles on its interambulacra are less fully defined in many
specimens. If more than a variety, it is certainly very closely related to C.texanwm and de-
scended from it. ;

Localities —Below the Missouri, Kansas & Texas Railway bridge on Big Elm Creek, Benton
County (type), and Denison, Grayson County, Tex.

Geologic horizon.—Denison formation of Washita group, Comanche series, Cretaceous.

Collection.—Geological Survey of Texas (A, B).

Genus COPTOSOMA Desor.

CoprosoMa speciosum Clark.
Plate XIX, figures 3a—h.
Cyphosoma speciosum Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.
Coptosoma speciosum Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, p. 51.
Coptosoma speciosum Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 52, 43, Pl. XVIII, figs. lah.
Coptosoma speciosum Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.
Pseudodiadema speciosum Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 286-
288, Pl. IX, figs. 7-14.

Determinative characters —Test circular, inflated at the sides, flattened on the upper and

lower surfaces. Ambulacra wide, with two rows of primary tubercles, twelve or thirteen in
39800°—15

5

62 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

each, that gradually diminish in size toward the poles; poriferous zones sinuous; pores uniserial.
Interambulacra with two rows of tubercles slightly larger than those of the ambulacra. Peri-
stome one-third the diameter of the test.

Dimensions.—Diameter 17 millimeters; height 9.5 millimeters.

Description.—This delicate species has a circular test with inflated sides. Both poles are
flattened, the lower more than the upper.

The ambulacra are wide and prominent, and bear two rows of large tubercles, twelve or
thirteen in each row. The areolas are nearly confluent above and below and are striated by
irregular radiating ridges. The bosses are deeply crenulated, and the small mamelons are imper-
forate. Minute tubercles and granules irregularly surround the primary tubercles, occurring
in greatest number along the central suture. The poriferous zones are slightly sinuous, the
three pore pairs haying a curved arrangement on each ambulacral plate.

The interambulacra are about one and one-half times as wide as the ambulacra. They
have two rows of primary tubercles that are somewhat larger than those of the ambulacra. The
areolas are very large and are confluent above and below. Throughout the greater part of the
column the two rows approach each other, but toward the apical system they are widely sepa-
rated from one another. The smaller tubercles are disposed in rows, with greater or less regu-
larity, on either side of the primary series.

Ths peristome is narrow, occupying a little more than one-third of the diameter of the test.
It has an irregular pentagonal outline. The discal opening is large and pentagonal in form.

Related forms.—This form is apparently closely related to C. mortoni, but is more elevated
and does not exhibit granules between the pores. ;

Locality.—Timber Creek, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia (1468). .

CopTosoMA MORTONI (De Loriol).
Plate XXII, figures la-e.

Cyphosoma mortont De Loriol, 1887, Recueil zool. Suisse, vol. 4, No. 3, pp. 389-391, Pl. XVII, figs. 2a-c.
Coptosoma mortoni Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, pp. 51, 52, Pl. XVII, figs. la-e.

Determinative characters.—Test circular, depressed. Ambulacra very wide, with two rows
of primary tubercles, thirteen in each row, the three or four at the ambitus large and nearly con-
fluent, but diminishing rapidly in size toward either pole; poriferous zones narrow, sinuous;
pores uniserial, those of each pair separated by a granule. Interambulacra with two rows of
tubercles, nine or ten in each row. Peristome very large.

Dimensions.—Diameter 12-15 millimeters; height about 6 millimeters. :

Description.—The writer has been unable to obtain a specimen of this species, but the very
full description and excellent figures given by De Loriol admit of its satisfactory identification.
The description that follows is largely a translation of that given by De Loriol. The two speci-
mens in the possession of De Loriol were so deformed that he could not determine the height
accurately. The test is circular and depressed. The ambulacra are relatively very wide,
almost as large as the interambulacra, and bear two rows of large tubercles, thirteen in each row.
The first fom or five tubercles from the apical system are fir apart nl very small. At the
ambitus three or four of the tubercles are very large, with nearly confluent areolas, but rapidly
diminish in size toward the lower surface, the last four or five being very small and with diffi-
culty distinguished. The areolas, except at the ambitus, are not large. The bosses are finely
crenulated and the mamelons small and imperforate. Upon the lower surface there are large
mammillated granules which can be with difficulty distinguished from the primary tubercles.
Each areola is also partially surrounded by a circle of small granules that occur most numer-
ously near the line of the central suture. The granules are few in number on the upper surface.
The poriferous zones are narrow, slightly smuous, and composed of small pores without any
increase between the apical system or peristome. A small granule is found between the pores
of each pair.

CRETACEOUS ECHINODERMATA. 63

The interambulacra bear two rows of primary tubercles that are similar to those of the ambu-
lacra, but larger and less numerous. The lower surface is covered by large mammillated granules
that can scarcely be distinguished from the tubercles, and also by numerous small ones. There
are few granules on the upper surface. The peristome is large, with slight incisions.

Related forms.—The species is most closely related to C. speciosum, but in form and in
several details of structure is unlike it. The presence of granules between the pores of the
present species is apparently marked.

Locality —Wahalak, Kemper County, Miss.

Geologic horizon.—Selma chalk, Upper Cretaceous.

Collection.—P. de Loriol, Switzerland.

Genus MICROPSIS Cotteau.

Mrcropsis LINEATUS Clark, n. sp.
Plate X XV, figures la-c.

Determinative characters—Test medium size, slightly polygonal in ambital outline, tumid
above, subhemispherical, slightly concave below. Apical system wanting. Ambulacra with
compound plates covered with two rows of primary tubercles perforate and crenulate. Inter-
ambulacra with six rows of primary tubercles, which rapidly decline in size above the ambitus.
Peristome small.

Dimensions.—Diameter 25.25 millimeters; height 12 millimeters.

Description.—The test is of medium size and slightly polygonal in ambital outline, with
tumid upper surface. It is subhemispherical and slightly concave on the lower surface.

The ambulacra are narrow and covered with two vertical rows of perforate and crenulate
primary tubercles. The poriferous zones are not sharply defined. The plates are compound,
with a low primary adorally.

The interambulacra have six rows of primary tubercles which decline rapidly in size above
the ambitus.

The peristome is small and with slight branchial incisions.

Locality.—Cut on Bonham road, southeast edge of Denison, Tex.

Geologic horizon.—Grayson marl member of the Denison formation, of Washita group,
Comanche series, Cretaceous.

Collection.—U. S. National Museum (31198).

Suborder ECHININA.
Family TRIPLECHINID®.

Genus PSAMMECHINUS Agassiz.
PsAMMECHINUS CrINGULATUS Clark.
Plate XXII, figures 2a-i.
Psammechinus cingulatus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.
Psammechinus cingulatus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Psammechinus cingulatus Clark, 1893, U. S. Geol. Survey Bull. 97, p. 55, Pl. XX, figs. la-i.
Psammechinus cingulatus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 6.
Psammechinus cingulatus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp.
288-289, Pl. X, figs. 1-9.

Determinative characters.—Test small, hemispherical, with circular outline; sides inflated;
upper surface elevated; base flattened and concave. Ambulacra wide, with two rows of
primary tubercles, sixteen or seventeen in each series; poriferous zones depressed, triserial.
Interambulacra about one and one-half times the width of the ambulacra; plates covered with
numerous uncrenulate and imperforate tubercles. Peristome large, with ten deep incisions.

Dimensions.—Diameter 22 millimeters; height 12.5 millimeters.

Description.—This delicate form, of which two very imperfect specimens were examined by
the writer, is hemispherical in shape, with circular circumference, inflated sides, elevated upper

64 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

surface, and flattened base. In the vicinity of the mouth opening the lower surface is depressed,
producing a slight concavity.

The ambulacra are wide and composed of eighteen to twenty plates. The lower sixteen or
seventeen of each series bear prominent tubercles that occur in a continuous line to the peristome.
On ‘either side of the primary tubercles are smaller ones of like shape. The three pore pairs are
arranged in semicircular form, the two upper separated from the lower by one of the secondary
tubercles.

The interambulacra are about one and one-half times as wide as the ambulacra and the
plates are about fifteen in number. Each plate bears a large tubercle in the center, and irregu-
larly arranged about it smaller tubercles of various sizes.

The peristome is large, with 10 deep incisions. The apical system is lacking, but the discal
opening is large and pentagonal in form.

Related forms.—This unique species is quite unlike any hitherto described, and is readily
characterized by the arrangement of the tubercles and pore pairs. As the only representative
of the genus in American Cretaceous deposits it has especial interest.

Locality.—Timber Creek, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia (1467).

Genus PEDINOPSIS Cotteau.
PEDINOPSIS SYMMETRICA (Cragin).
Plate XXIII, figures la-h.

Dumblea symmetrica Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 150, Pl. XXXIV, fig. 12, Pl. XXV, figs.
4-7; Pl. XXVII, fig. 1.

Determinative characters.—Test medium size, subconical, inflated on the aboral surface, con-
cave on the adoral surface, sides tumid. Ambulacra with several vertical rows of primary per-
forate tubercles, poriferous zones broad, pore pairs biserial. Interambulacra broad and low
with many rows of primary tubercles similar to those of the ambulacra. Apical system small,
madreporite large, posterior right-hand ocular reaches the periproct. Peristome small.

Dimensions.—Diameter 15 to 45 millimeters; height 12 to 33 millimeters.

Description.—The species referred by Cragin to a new genus which he named Dumblea is
evidently a representative of the genus Pedinopsis. A specimen referred to J. W. Gregory of
Glasgow was pronounced by him to be a typical Pedinopsis.

The test is of medium size, tumid, subconical, flattened and concave on the lower surface.
The circular ambital outline is somewhat broken by the sutures between the ambulacra and
interambulacra producing an imperfectly defined 15-lobed appearance.

The ambulacra are rather broad with well-defined poriferous zones. They are covered with
two rows of primary tubercles in the smaller and four in the larger specimens. These tubercles
are perforate and apparently plain or uncrenulate, although the state of preservation makes it
uncertain as to whether delicate crenulation may not have existed.

The interambulacra are broad and low with many vertical rows of primary tubercles similar
to those of the ambulacra. They diminish in number aborally.

The apical system is small, the madreporite being large and encroaching on the adjacent
genitals. The posterior right-hand ocular reaches the periproct.

The peristome is small with well-marked branchial incisions. The periproct is oval.

Localities.—Sierra Blanca peaks (type) and near Kent, El Paso County, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collections. Geological Survey of Texas; U.S. National Museum.

CRETACEOUS ECHINODERMATA. 65

PEpINOPsIS PONDI Clark.

Plate XXIV, figures 1la-d.

Pedinopsis pondi Clark, 1893, Johns Hopkins Uniy. Cire., vol. 12, No. 103, p. 51.
Pedinopsis pondi Clark, 1893, U. S. Geol. Survey Bull. 97, p. 57, Pl. XXI, figs. la-b; Pl. XXTI, figs. lac.

Determinative characters.—Test large, circular, inflated at the sides, convex on the upper
surface. Ambulacra with six rows of tubercles at the ambitus, the two marginal rows complete
and the four inner incomplete; poriferous zones broad, biserial. Interambulacra with 20
rows of tubercles at the ambitus, which become reduced to four at the margin of the peristome;
tubercles small, equal, crenulate, and perforate. Peristome small, with distinct incisions.

Dimensions.—Diameter 88 millimeters; height 58 millimeters.

Description.—The very large specimen on which this species is established has portions of:
the test in a very perfect state of preservation. The test is large, circular, inflated at the sides,
and convex on the upper surface. The lower surface is flattened, with a slight concavity in
the region of the peristome.

The ambulacra are wide, and have at the ambitus six rows of tubercles, the two marginal
rows alone continuing from the discal opening to the peristome. The four inner rows are incom-
plete, but of equal size with the outer. The tubercles are finely crenulated and perforated. The:
poriferous zones are broad and biserial, except on the lower surface, where the pore pairs become:
crowded together. Near the peristome they again broaden out and become greatly increased
in number at the margin. The pores are small and round.

The interambulacra are broad and have twenty rows of tubercles at the ambitus, which
become reduced to four at the peristome. The tubercles are of equal size with those of the
ambulacra. Small mammillated granules are found scattered over both the ambulacral and
interambulacral plates, together with a fine granulation covering the entire surface.

The peristome measures about seven-eighths of an inch in diameter. It has 10 distinct
incisions in the interambulacra. The discal opening is partly outlined but is very indistinct.

This species is named for Edwin J. Pond, of the United States Coast and Geodetic Survey,,
by whom the specimen described by the writer was discovered.

Locality.—The south bank of Onion Creek, about one-fourth mile southwest of the crossing
of the Austin and San Antonio wagon road, Travis County, Tex.

Geologic horizon.—Austin chalk, Upper Cretaceous.

Collection.—Johns Hopkins University (T 3008).

Subclass IRREGULARIA.

Order GNATHOSTOMATA.
Suborder HOLECTYPINA.
Family PYGASTERID #.
Genus HOLECTYPUS Desor.
Ho.ecryrus PLANATUS Roemer.
Plate XXV, figures 2a-f, 3a—c, 4, Plate X XVI, figures la-e.

Holectypus planatus Roemer, 1849, Texas, p. 393.

Holectypus planatus Roemer, 1852, Die Kreidebildungen von Texas, p. 84, Pl. X, fig. 2.

Holectypus planatus Shumard, 1852, Exploration Red River of Louisiana Rept., p. 211.

Holectypus planatus Giebel, 1853, Naturwiss. Ver. in Halle Jahresb., p. 373.

Holectypus planus Giebel, 1853, idem.

Holectypus planatus Conrad, 1857, U. 8. and Mex. Boundary Survey Rept., vol. 1, pt. 2, p. 145, Pl. I, fig. 4.
Holectypus planatus Desor, 1858, Synopsis des échinides fossiles, p. 174.

Holectypus planatus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.

Holectypus planatus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.

66 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Holectypus sp. Roemer, 1888, Pal. Abhandl. von Dames und Kayser, vol. 4, pt. 4, p. 9 (287), Pl. I (XX X1), figs. 6a-c.
Holectypus planatus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.

Holectypus planatus Clark, 1893, Johns Hopkins Univ. Cire., vol: 12, No. 103, p. 51.

Holectypus planatus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 58, 59, Pl. XXII, figs. 2a-f.

Holectypus charltoni Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 158, Pl. XXTV, figs 8, 9.

Holectypus planatus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 159, 160.

Holectypus transpecosensis Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 160, Pl. XX VII, figs. 3-5.
Holectypus charltoni Cragin, 1894, Colorado Coll. Studies, vol. 5, p. 41.

Holectypus planatus Hill, 1901, U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, p. 226.

Determinative characters.—Test subcircular, subconical, flattened on the under surface.
Ambulacra narrow, straight, and somewhat lanceolate, with six irregular rows of tubercles;
poriferous zones somewhat straight, narrow, unigeminal. Interambulacra wide, plates numer-
ous and narrow, each with a nearly horizontal row of small tubercles. Apical system small, the
madreporite large. Peristome small, subcircular. Periproct large.

Dimensions.—Transverse diameter 12-70 millimeters; height 7—40 millimeters.

Description.—This very common form from the Cretaceous of Texas was first reported by
Roemer in 1849, and was subsequently, in 1852, more accurately defined and figured by him.
Although wide differences in outline and in the size and arrangements of the tubercles occur,
they appear to be rather individual than specific. The majority of the specimens are subcir-
cular; in the case of some, however, distinctly circular, while in that of others clearly pentagonal.
The ambitus in some individuals is sharp, in others rounded, while the upper surface is dis-
tinctly elevated at the center with slightly tumid sides. The under surface is flat and slightly
depressed in the vicinity of the peristome.

The ambulacra are narrow, straight, increasing in width toward the ambitus and somewhat
lanceolate in form. The poriferous zones are narrow, the pores small and unigeminal. Six
rows of small tubercles are found in the broader portion of the areas, which become reduced to
four toward the apical disk and peristome.

The interambulacra are about three times the width of the ambulacra at the ambitus. The
plates are narrow, each with a horizontal row of small tubercles, five or stx in a row at the am-
bitus, but fewer above and below. Each tubercle has a small circular areola, crenulated boss,
and perforated mamelon. The tubercles cover the greater portion of the plates, with minute
granules interspersed between them. The tubercles are very much larger on the lower surface,
and the difference in size shown between those of the ambulacra and interambulacra on the
upper surface disappears.

The apical system is small. The five ovarial plates are all perforated; the madreporite is
of large size and indistinctly separated from the other plates.

The peristome is small, with slight incisions that give a decagonal margin. The large oval
peristome extends from the vicinity of the mouth to the ambitus. f

Related forms.—The size of the adult forms is very variable, those found in the Washita
eroup being larger than those found in the Trinity and Fredericksburg group. The individuals
also vary in height. So many connecting forms can be found between the typical H. planatus
and the species described as H. charltoni and H. transpecosensis by Cragin that they have been
regarded as synonyms.

Localities —Near Fredericksburg (type), Cow Creek, Travis County (figured specimens A
and B); Denton County (figured specimen C); Shoal Creek, Austin (figured specimen D); San
Antonio, Kent, and many other localities in Texas.

Geologic horizon.—Trinity, Fredericksburg, and Washita groups of the Comanche series,
Cretaceous.

Collections —U. S. National Museum (12236); Academy of Natural Sciences of Phila-
delphia; Boston Society of Natural History; Geological Survey of Texas; Johns Hopkins
University (T 3008).

CRETACEOUS ECHINODERMATA. 67
Suborder CLYPEASTRINA.
Family CLYPEASTRID®.

Genus ECHINANTHUS Leske.
EcuHINANTHUS MORTONIS (Michelin).

Pygorhynchus mortonis Michelin, 1850, Rey. et mag. zoologie, vol. 2, p. 240.
Hardouinia mortoni D’ Archiac and Haime, 1853, Foss. numm. de |’ Inde, p. 214.
Echinanthus mortonis Desor, 1858, Synopsis des échinides fossils, p. 295.
Echinanthus mortonis Dujardin and Hupé, 1862, Hist. nat. zoophytes échin., p. 584.
Echinanthus mortonis Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.
Echinanthus mortonis Conrad, 1866, Check list, p. 22.
Echinanthus mortonis Quenstedt, 1872-1875, Petrefac. Deutsch., p. 692.

Description.—The author has been unable to examine a specimen of this species. Desor
gives the following description:

Espéce remarquable entre tous les Echinanthus par sa forme élevée, conique, 4 peu prés aussi large que longue,
rappelant un peu les Pygurus par sa physionomie. Sommet ambulacraire légérement excentrique. Pétales larges,
pointus 4 leur extrémité, dépassant un peu la moitié de la distance entre le sommet et le bord. Périprocte grand,
situé & mi-distance du sommet, 4 l’origine d’un large et profond sillon. Dessous concave. Péristome 4 peu pres
central, petit, entouré d’un floscelle trés accusé.

D’Archiac and Haime proposed to make of this species the type of a new genus which they
called Hardouinia. Notwithstanding the fact that the floscelle is somewhat more pronounced
than in any of the other species Desor and others who examined the form considered that the
characters were not sufficiently pronounced to justify a generic separation from Echinanthus.

Locality.—Pontotoc, Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous. The reference of this form to the
Tertiary by earlier authors is evidently incorrect.

Collection.—Unknown. Desor mentions its presence in the collection of Verneuil.

Genus SCUTELLASTER (?) Cragin.
?SCUTELLASTER CRETACEUS Cragin.
Scutellaster cretaceus Cragin, 1895, Am. Geologist, vol. 15, pp. 90, 91.

Description.—The specimen on which this genus and species are based is so imperfect that
it seems better to defer the acceptance of both until more diagnostic material is obtained.
Cragin in a letter to the author says: ‘‘I fear it [Scutellaster] is not after all a new genus as
I supposed when I described it as such.”

Locality.—East slope of Shooks Run, Platt Avenue, Colorado Springs, Colo.

Geologic horizon.—Arenaceous shale of Fox Hills sandstone of Montana group, Upper
Cretaceous.

Collection.—Colorado College.

Order ATELOSTOMATA.
Suborder ASTERNATA.
Family ECHINONEID®.
Genus PYRINA Desmoulins emend. De Loriol.
Pyrina PARRyYI Hall.
Plate XX VII, figures la-j.

Pyrina parryi Hall, 1857, U. S. and Mex. Boundary Survey Rept., vol. 1, pt. 2, p. 144, Pl. I, figs. 1-1d.
Pyrina parryi Gabb, 1859, Catalogue Invertebrate Fossils Cretaceous, p. 19.

Pyrina parryi Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.

Pyrina parryi Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.

68 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Pyrina parryi Aguilera, 1893, Datos para la geologfa de México, p. 26.

Pyrina parryi Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 51.
Pyrina parryi Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 59, 60.

Pyrina bulloides Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 162.
Pyrina parryi Aguilera, 1897, Inst. geol. México Bol. Nos. 4, 5, 6, p. 215.
Pyrina parryi Bosé, 1899, Inst. geol. México Bol. No. 13, p. 11.

Determinative characters.—Test subpentagonal, broader anteriorly than posteriorly, inflated
at the sides, flattened above and below. Ambulacra narrow, uniserial; both areas covered with
minute sraiernellea:

Peristome large, elliptical, oblique. Periproct oval, supramarginal.

Dimensions.—Length 20 to 35 millimeters; width 18 to 30 millimeters; height 12 to 25
millimeters.

Description.—The test is regular and symmetrical, slightly pentagonal in outline, enlarged
anteriorally, contracted posteriorly. The upper surface is convex, although somewhat flattened
at the summit. The sides are inflated, the base flattened and slightly depressed in the vicinity
of the peristome.

The ambulacra are narrow and lanceolate; the poriferous zones straight and depressed,
the pores small, oval, and uniserial. The interambulacra are broad and less elevated than the
ambulacra. Both the ambulacra and the interambulacra support numerous small tubercles
that are larger and more distinct on the lower than the upper surface. Fine microscopic gran-
ules are disseminated between the tubercles.

‘The peristome is large, elliptical, and obliquely situated slightly in front of the center of the
base. The periproct is oval and placed nearly in the center of the posterior margin. The apical
‘system is small, composed of four genital plates, the large right antero-lateral modified to form
the san dinepanie. The five small ocular plates are mle: wedged between the ovarial plates.

Related forms.—The species just described is the only Temmaneninina of this genus from
American strata and both in form and structural features admits of a ready separation from all
European species. It presents some points of similarity with Pyrina desmoulinsw D’Archiac,
but is broader posteriorly and less elevated. The many specimens of this common species which
have come under the observation of the author show considerable variation, but are all regarded |
as representing a single species.

Localities—Leon Springs (type), near San Antonio, Pilot Knob (Travis County), Kent,
Sierra Blanca peaks, and many other localities in Texas.

Geologic horizon.—Fredericksburg and Washita groups, Comanche series, Cretaceous.

Collections. —U. S. National Museum (9854); Johns Hopkins Sinivestiy.

Family NUCLEOLITIDA.
Genus BOTRIOPYGUS D’Orbigny.
BorTriopyGUS ALABAMENSIS Clark.
Plate XXIV, figures 2a-f.

Botriopygus alabamensis Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.
Botriopygus alabamensis Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 51.
Botriopygus alabamensis Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 60, 61, Pl. XXV, figs. la-f.

Determinative characters.—Test oblong; more or less depressed on upper surface, highest
anteriorly; under surface concave. Ambulacra broad, lanceolate; poriferous zones subpetaloi-
Jal above. Interambulacral plates covered with numerous, irregularly distributed tubercles.
Avical system anteriorly situated. Peristome small, oblique, forward of the center.

Dimensions.—Length 63 millimeters; width 54 millimeters; height 26 millimeters.

Description.—The single imperfectly preserved specimen of this species, although apparently
lacking some of the characteristics of Botriopygus, is nevertheless referred to that genus. The
test is oblong, considerably depressed on the upper surface, and concave on the base. ‘The apex

CRETACEOUS ECHINODERMATA, 69

of the upper surface is forward of the center, making the anterior margin full, the posterior
flattened.

The ambulacra are broad and lanceolate. They contract appreciably just above the ambi-
tus, giving to the poriferous zones a subpetaloidal form. The pores of the subpetaloidal portions
ave large and oval, those of the outer rows more elongated than those of the inner and acumi-
nated on their inner margins. The pores of each pair are united by a furrow. The inner por-
tions of the ambulacral plates are covered with tubercles, which in the broadest portion of the
subpetaloidal areas reach five or six in number. Below the subpetaloidal areas the pores recede
from the outer margin of the plates. Those of each pair are close together, small, and nearly
round, and the plates also become broader.

The interambulacral plates are large and covered with numerous, irregularly arranged tuber-
cles. A microscopic granulation covers the intertubercular space.

The position of the apical system is forward of the center of the upper surface, although none
of the plates are preserved on the specimen examined. The peristome is small and obliquély
placed slightly in front of the center of the base.

Related forms.—Under the name of B. elevatus Gabb describes a species from Peru that is not
unlike B. alabamensis in many particulars. B. alabamensis, however, is larger, less rounded ante-
riorly, and has a more depressed posterior margin.

Locality.— Alabama.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia.

Genus ECHINOBRISSUS Breyn.
ECHINOBRISSUS ANGUSTATUS Clark, n. sp.
Plate X XVII, figures 2a-c.

Determinative characters._-Test small, subovate, rounded anteriorly, subquadrate poste-
riorly; upper surface elevated; apex forward of the center; base concave. Ambulacra lanceo-
late. Peristome small, excentric; periproct small in broad shallow sulcus, placed well posteri-
orly.

Dimensions.— Length 15.5 millimeters; width 14 millimeters; height 8.5 millimeters.

Description — This small form is subovate in ambital outline, is rounded anteriorly and
truncated posteriorly, giving a subquadrate effect. The upper surface is elevated and the lower
concave.

The ambulacra are very indistinct on the type. The apical system is forward of the center
but the individual plates are indistinguishable. The peristome is small, deeply depressed and
excentric in front. The periproct is small in a broad shallow sulcus and placed well posteriorly.

Locality Shoal Creek, Tex.

Geologic horizon.—Buda (Shoal Creek) limestone of Washita group, Comanche series, Cre-
taceous.

Collection.— Johns Hopkins University (T 3009).

ECHINOBRISSUS EXPANSUS Clark.
Plate XXVIII, figures la-g.
Echinobrissus expansus Clark, 1891, Johns Hopkins Univ. Circ., vol.10, No. 87, p. 76.
Echinobrissus expansus Clark, 1893, Johns Hopkins Univ. Cire., vol 12, No. 103, p. 52.

Echinobrissus expansus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 61, 62, Pl. X XVI, figs.
Echinobrissus expansus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc. vol. 57, p. 6.

ob

Determinative characters.—Test subquadrate, broader posteriorly, moderately convex on
upper surface, concave on the base. Ambulacra narrowly lanceolate. Periproct large, supra-
marginal; anal sulcus broad, deep, extending from near the apex to the ambitus. Peristome
large, situated in front of the middle of the base.

70 ; MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions—Leneth 27 millimeters; width 27 millimeters; height 12 millimeters.

Description.—This typical Echinobrissus is of a moderate size, somewhat depressed above,
and subquadrate in marginal outline. The posterior portion is broader than the anterior and
distinctly lobed. The base is concave.

The ambulacral areas are narrowly lanceolate, and on the upper surface the poriferous zones
are subpetaloidal. The inner rows of pores are round, the outer oval, with acuminated imner
margins and obliquely placed. The interambulacral areas are formed of broad plates that bear
numerous small perforated and mammillated tubercles. A microscopic granulation covers the
mihary space.

The apical system is small and compact and the perforations of the genital plates distinct.

The peristome is large, excentric, situated at some distance in front of the center of the base.
The periproct is large, acuminated on the upper margin, and placed in a broad, deep anal sulcus
that extends from near the apical system to the posterior margin.

Related forms.—Echinobrissus expansus has few points that would closely ally it with any
species of this genus hitherto described.

Locality——Alabama or Mississippi.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection Academy of Natural Sciences of Philadelphia (1465).

EcHINOBRISSUS TEXANUS Clark.
Plate XXVIII, figures 2a-f.

Echinobrissus texanus Clark, 1891, Johns Hopkins Univ. Cire., vol 10, No. 87, p. 76.
Echinobrissus teranus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Echinobrissus texanus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 62, 63, Pl. X XVI, figs. 2a-f.
Echinobrissus texanus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 150.

Determinative characters—Test ovate, rounded anteriorly, subquadrate posteriorly; upper
surface convex, apex forward of the center; base concave. Ambulacra lanceolate, subpetaloidal.
Apical system forward of the center. Peristome small, excentric. Periproct small, oval, in
narrow sulcus that begins some distance below the apical disk.

Dimensions.—Length 18.75 millimeters; width 16.5 millimeters; height 9.5 millimeters.

Description.—The single specimen of this species is somewhat damaged on the sides, so that
the ambital outline is not complete. It is ovate in form, broader posteriorly and subquadrate.
The upper surface is convex, but more or less compressed. The lower surface is concave.

The ambulacra are narrowly lanceolate. The poriferous zones for a short distance from the
apical system are subpetaloidal in form. The posterior ambulacra are much longer than the
others, the unpaired ambulacrum being the shortest. The pores of each plate are oval and set
at an angle to one another.

The interambulacral plates are large and covered with irreguarly arranged tubercles.
Between the tubercles a microscopic granulation covers the surface.

The apical system is small and situated forward of the apex. The individual plates can not
be fully distinguished on the specimen examined. The peristome is apparently small, though
somewhat obscured. It is situated forward of the center of the base.

The periproct is small, placed in a narrow sulcus that begins some distance posterior to the
apical system.

Related forms.—Echinobrissus texanus is readily separated from EH. expansus by its ovate
form and the shape and size of the anal sulcus. It is unlike any European species.

Locality South bank of Colorado River, Austin, Tex.

Geologic horizon.—Austin chalk, Upper Cretaceous.

Collection.—U. S. National Museum (20266).

CRETACEOUS ECHINODERMATA. al
Genus TREMATOPYGUS D’Orbigny.
TREMATOPYGUS CRUCIFERUS (Morton).

Plate XX VIM, figures 8a-c; Plate XXIX, figures la-f.

~Ananchytes cruciferus Morton, 1830, Am. Jour. Sci., Ist ser., vol. 18, p. 245, Pl. IIT, fig. 8.

Ananchytes cruciferus Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, pp. 201, 202.
~ Nucleolites crucifer Morton, 1833, Am. Jour. Sci., Ist ser., vol. 23, p. 294.

Nucleolites crucifer Morton, 1834, Synopsis Organic Remains Cretaceous, p. 75, Pl. III, fig. 15.
—Nucleolites cruciferus Agassiz, 1840, Catalogus systematicus, p. 4.

Nuculites cruciferus Agassiz and Desor, 1847, Catalogue raisonné, p. 97.

Nuculites crucifer Bronn, 1848, Index paleontologicus, vol. 1, p. 818.

Nucleolites cruciferus D’Orbigny, 1850, Prodrome, vol. 2, p. 271, étage 22, No. 1197.

Pygorhynchus crucifer Ravenel, 1850, Am. Assoc. Ady. Sci. Proc., p. 160.

Trematopygus crucifer D’Orbigny, 1853-60, Paléontologie frangaise, vol. 6, p. 387, Pl. CMLIII, figs. 10, 11; Pl. CMLXIII,

figs. 1-5.

Echinobrissus crucifer D’Orbigny, 1854, Rey. et mag. zoologie, ser. 2, vol. 6, p. 25.

Nucleolites crucifer Desor, 1858, Synopsis des échinides fossiles, p. 262.

Nuculites crucifer Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Nuculites crucifer Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.

Nuculites crucifer Cook, 1868, Geology of New Jersey, p. 377.

Nuculites crucifer Conrad, 1868, Geology of New Jersey, App. A, p. 722.

Nuculites cruciferus Credner, 1870, Deutsche geol. Gesell. Zeitschr., vol. 22, p. 217.

Trematopygus crucifer Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.

Trematopygus crucifer Clark, 1893, John: Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Trematopygus crucifer Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 63, 64, Pl. X XVII, figs. 1a-i.

Trematopygus crucifer Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Trematopygus cruciferus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 289-290,

Pl. XI, figs. 1-9.

Determinative characters —Test ovate, inflated at the sides and base and slightly con-
tracted anteriorly. Ambulacra long, well defined; pores uniserial, prominent on the upper sur-
face, indistinct on the base. Apical system situated anteriorly. Peristome large and oblique.
Periproct large, oval, supramarginal.

Dimensions.—Length 18 to 20 millimeters; breadth 15 to 22 millimeters; height 10 to 14
millimeters.

Description.—This species is not uncommon at Timber Creek, N. J., where many very perfect
specimens have been obtained. Its outline is ovate and very regular, lacking at the ambitus or
apex any sharply defined angularity. The sides are highly inflated together with the outer
portion of the base.

The ambulacra are long, lanceolate, and unequal; the posterior pair are the longest, the
unpaired anterior one is the shortest. They do not produce any irregularity in the outline of
the test beyond inconsiderable depressions in the immediate vicinity of the peristome. The
poriferous zones are clearly marked on the upper surface, and the pore pairs are nearly horizontal,
but toward the ambitus the pores become smaller, those of each pair nearer together, and the
pairs obliquely situated at the lower, outer corner of each plate; near the peristome they again
become larger and slightly increased in number.

The interambulacra are wide and composed of large plates that are bent in the middle.
The surface is covered with irregular rows of tubercles that are perforated and mammillated.
The miliary space is covered with numerous minute and irregularly distributed granules.

The apical system is small and anteriorly situated; the four genital plates are distinctly
perforated; those of the anterior pair are much nearer together than those of the posterior.

The peristome is large, oblique, and placed somewhat forward of the center of the base.
The periproct is large, oval, and acuminate at the upper extremity. It is situated in an anal
sulcus that makes a marked indentation in the posterior margin, and is bordered by two well-
defined ridges.

Related forms.—Trematopygus cruciferus (Morton) is a unique species that has no closely
allied forms in either American or European deposits.

72, MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Locality.—The yellow limestone of Timber Creek and Vincentown (type), N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections—American Museum. of Natural History, New York; Academy of Natural
Sciences of Philadelphia (1464); Johns Hopkins University.

Family CASSIDULIDA.

Genus PYGURUS Agassiz.

?PyGURUS GEOMETRICUS (Morton).

Clypeaster sp. Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, p. 202.
Clypeaster geometricus Morton, 1833, Am. Jour. Sci., Ist ser., vol. 24, p. 131, Pl. X.

Clypeaster geometricus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 76, Pl. X, fig. 10.
Pygurus geometricus Agassiz and Desor, 1847, Catalogue raisonné, p. 141.

Clypeaster geometricus Bronn, 1848, Index palontologicus, vol. 1, p. 312.

Pygurus geometricus D’Orbigny, 1850, Prodrome, vol. 2, p. 270.

Pygurus geometricus D’Orbigny, 1853-60, Paléontologie frangaise, vol. 6, p. 313, Pl. CMXX, fig. 4.
Pygurus geometricus Desor, 1858, Synopsis des échinides fossiles, p. 313.

Clypeaster geometricus Gabb, 1859, Catalogue Invertebrate Fossils Cretaceous, p. 18.

Pygurus (2) geometricus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Pygurus (2) geometricus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 92, 93.

Pygurus (?) geometricus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

The type of this species was examined by the writer, but its state of preservation (that of a
poor cast) is such that its generic relations can not be with certainty determined. Until further
material is obtained it seems best to defer its recognition. Although originally described. by
Morton as a Clypeaster, it has been referred to the genus Pygurus by Agassiz, D’Orbigny, and
Desor.

Locality.—Delaware and Chesapeake Canal, Delaware.

Geologic horizon.—Matawan formation, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia.

Genus CATOPYGUS Agassiz.

CatTorpyGus OviroRMis Conrad.
Plate XXIX, figures 2a-f.

Catopygus oviformis Conrad, 1847, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 39, Pl. I, fig. 9.
Nuclcolites oviformis (Catopygus) Conrad, 1868, Geology of New Jersey, App. A, p. 722.
Catopygus oviformis Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.

Catopygus oviformis Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Catopygus oviformis Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 64, 65, Pl. XX VII, figs. 2a-f.
Catopygus oviformis Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

.

Determinative characters.—Test ovate, broader posteriorly; upper surface nearly flat; apex
posterior to apical disk. Ambulacra narrow, subpetaloidal. Interambulacra wide; single inter-
ambulacrum elevated. Apical system excentric, nearer the anterior border. Peristome small,
excentric, nearer the anterior margin. Periproct oval, situated in a narrow sulcus, that termi-
nates above in a projecting arch.

Dimensions.—Characteristic specimen: Length 25 millimeters; width 21.9 millimeters;
height 14 millimeters.

Description.—The test of this very beautiful little form is ovate, with rounded, inflated
sides and elevated upper surface. The base is nearly flat, slightly concave in the vicinity of the
peristome, and lobed posteriorly.

The ambulacra are narrowly lanceolate, subpetaloidal on the upper surface, the posterior
areas being much longer than the others. The plates in the petaloid portions are narrow but
beyond increase in breadth.

The interambulacral plates are covered with minute tubercles, between which are numerous
microscopic granules.

CRETACEOUS ECHINODERMATA, 73

The apical system is small, excentric, and situated far anterior to the apex.

The peristome is small and situated nearer the anterior margin.

The periproct is oval and placed at the upper part of a nearly vertical anal suleus. The
upper margin of this sulcus forms a beak-shaped prominence that overhangs the opening.

Related forms.—C. oviformis is separated from C. pusillus Clark, by its narrower outline,
more inflated sides, and the anterior position of its apical system. In form it is somewhat like
C. columbarius of Europe, but is distinguished from it by the position of the apical system.

Locality.—Timber Creek, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia (1477).

CaTopreus PusILLus Clark.
Plate XXTX, figures 3a-d.
Catopygus pusillus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.
Catopygus pusillus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.
Catopygus pusillus Clark, 1893, U. 8S. Geol. Survey Bull. 97, pp. 65, 66, Pl. X:X VII, figs. 3a-d.
Catopygus pusillus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, p. 292, Pi. XT,
figs. 16-19.

Determinative characters.—Test ovate to subquadrate, rounded anteriorly, subquadrate
posteriorly, broader behind than before; upper surface elevated; base concave. Ambulacra
narrowly lanceolate, subpetaloidal on the upper surface. Apical system small, nearly central.
Peristome small, anteriorly placed. Periproct oval in vertical sulcus beneath overhanging arch.

Dimensions.—Characteristic form: Length 15.6 millimeters; width 14 millimeters; height
9.4 millimeters.

Description.—All the specimens of this species examined by the writer are casts, which are,
however, sufficiently well preserved to allow determination of all the more important characters.
The test is ovate to subquadrate, occasioned by the slight angularity of the posterior margin.
‘The anterior portion is regularly rounded.

The ambulacra are narrow, the posterior pair only slightly longer than the anterior.

The interambulacra are wide and composed of Jarge plates.

The apical system is small and situated nearly in the center of the upper surface.

The peristome is small and placed forward of the center of the base. The periproct is situ-
ated in a nearly vertical sulcus that is overhung at its upper extremity by a projecting arch.

Related forms.—Catopygus pusillus is separated from C. oviformis by its broader and slightly
-subquadrate form, its less rounded sides, and nearly central position of its apical system.

Locality.—W ordills, Monmouth County, N. J.

Geologic horizon.—Merchantville clay of Matawan group, Upper Cretaceous.

Oollection.—U. S. National Museum (2210).

CaTOPYGUS WILLIAMSI Clark.
Plate X XIX, figures 4a-d.

Catopygus williamsi Clark, 1907; in Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp.
292-293, Pl. XII, figs. 1-4.

Determinative characters.—Test ovate, slightly broader posteriorly; upper surface rounded
and somewhat elevated; lower surface concave. Apex posterior to apical system. Ambulacra
subpetaloidal. Peristome small, near anterior margin. Periproct small, low down on slightly
truncated posterior margin.

Dimensions.—Length 26 millimeters; width 22 millimeters; height 15 millimeters.

Description.—The single specimen of this species is a well-preserved cast that clearly shows
all of the more important diagnostic features. The test is ovate, slightly broader posteriorly.
The posterior margin is but little truncated, affording a nearly oyal outline to the ambitus.
The upper surface is somewhat elevated, but it is not a highly inflated form. The lower surface
is clearly concave.

74 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacra are subpetaloidal on the upper surface. The posterolateral ambulacra
are somewhat longer than the others.

The apical system is slightly excentric, being situated anterior to the apex.

The peristome is small, pentapetaloidal and situated well anteriorly. The periproct 1s
small, low down on the overhanging, truncated posterior margin.

Related forms.—This species is distinct from either C. oviformis or C. pusillus. Its posterior
margin and the position of its periproct very readily separate it.

Locality — Bluff east of Atlantic Highlands, N. J.

Geologic horizon.—Navesink marl of Monmouth group, Upper Cretaceous.

Collection.—Johns Hopkins University (T 3010).

CaTOPYGUS sp.
Catopygus sp. indet. Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, p. 293.

A poorly preserved specimen of Catopygus presents some points of similarity to C. pusilus
but apparently differs from it in other features. In its imperfect state of preservation it can
not be assigned with certainty to that species. Some of the most important diagnostic charac-
ters are lacking.

Locality.—Beers Hill Cut, south of Keyport, N. J.

Geologic horizon.—Tinton sand member of the Redbank sand, Monmouth group, Upper
Cretaceous.

Collection.—New Jersey Geological Survey.

Genus CASSIDULUS Lamarck.

CASsIDULUS FLOREALIS (Morton).
Plate XXX, figures la-l.

Olypeaster sp. Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser. vol. 6, p. 202.

Clypeaster florealis Morton, 1833, Am. Jour. Sci., Ist ser., vol. 23, p. 294.

Clypeaster florealis Morton, 1834, Synopsis Organic Remains Cretaceous, p. 76, PI. III, fig. 12, and Pl. X, fig. 12.
Pygurus florealis Agassiz and Desor, 1847, Catalogue raisonné, p. 141.

Clypeaster florealis Bronn, 1848, Index palzeontologicus, p. 312. '
Faujasia florealis D’Orbigny, 1853-1860, Paléontologie frangaise, vol. 6, p. 319, Pl. CMXX, figs. 5, 6.
Faujasia florealis Desor, 1858, Synopsis des échinides fossiles, p. 318.

Clypeaster florealis Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.

Cassidulus florealis Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.

Pygurus florealis Conrad, 1868, Geology of New Jersey, App. A, p. 722.

Cassidulus florealis Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.

Cassidulus florealis Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Cassidulus florealis Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 66, 67, Pl. XXVIII, figs. la-l.
Cassidulus florealis Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Determinative characters.—Test subconical in outline, subpentagonal, slightly longer in
the anteroposterior diameter than the lateral, rounded anteriorly, angular posteriorly; apex
slightly forward of the center. Ambulacra narrow; poriferous zones petaloidal on the upper
two-thirds of the dorsal surface. . Interambulacra wide, covered with small perforated tubercles.
Apical system small, situated anteriorly. Peristome pentagonal, with well developed floscelle.
Periproct supramarginal, in a short, narrow sulcus.

Dimensions—Length 35 millimeters; breadth 32 millimeters; height 19 millimeters.

Description.—This species, the earliest of this genus recognized from American deposits,
has a subconical test of moderate height, with a subpentagonal margin. The angularity is more
pronounced posteriorly than anteriorly, the anterior portion of the margin being distinctly
rounded. The anteroposterior diameter is but slightly greater than the lateral, while the height
is a little more than one-half of the same. The apex is a short distance in front of the center
of the upper surface, the slope of the anterior face being sharper than that of the posterior.

The ambulacra are narrow. The poriferous zones consist of a double row of pores that are
arranged in petaloidal form on the upper two-thirds of the dorsal surface and as phylloidal
expansions in the vicinity of the mouth edges. In the petaloidal portion the pores of the inner

CRETACEOUS ECHINODERMATA. 75

row are oval, those of the outer elongated, and each pair united by a shallow furrow. Toward
the margin the pores are smaller and placed near together and so continue until near the peris-
tome, where the poriferous zones suddenly expand. At this point the pores increase in size and
distance from one another. Between the oral lobes the poriferous zones again suddenly
contract.

The interambulacra are of unequal width; the anterior pair are the narrowest; the three
posterior are of about equal width and nearly one-half wider than the anterior. The surface of
the plates is irregularly covered with numerous small perforated tubercles, with sunken areolas
between which are numerous microscopic granules.

The apical system is composed of four perforated genital and five small ocular plates. The
fifth genital is obsolete. The large right anterolateral genital plate, the madreporite, extends
across the disk, forming a large portion of the center of that body.

The peristome is large, pentagonal, and slightly nearer the anterior margin. It is sur- |
rounded by five prominent lobes that project over the oral opening. The ambulacra are con-
tracted between the lobes and expand beyond them into wide phylloidal areas, producing a
peculiar, somewhat star shaped form that has been termed the floscelle.

The periproct is small, circular, and supramarginal, and is situated in a short, narrow sulcus.

Related forms.—Cassidulus florealis is allied to C. zquoreus, although the latter is more
depressed and more elongated. In some points it is similar to C. subconicus but has a less
sharply defined pentagonal outline, a differently situated periproct, and less elongated pores
in the outer rows of the petaloidal areas.

Localities.—Chesapeake & Delaware Canal, Del. (type); Uniontown, Ala.

Geologic horizon.—Matawan formation, Delaware, and Selma chalk, Alabama, of the
Upper Cretaceous.

Collection.—Academy of Natural Sciences of Philadelphia (1495).

CASSIDULUS #QUOREUS Morton.
Plate XXX, figures 2a-i.
Cassidulus xquoreus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 76, Pl. III, fig. 14.
Cassidulus equoreus Desmoulins, 1837, Etudes sur les échinides, p. 146.
Cassidulus xquoreus Lamarck, 1840, Hist. Nat., vol. 3, p. 341.
Cassidulus xquoreus Agssiz and Desor, 1847, Catalogue raisonné, p. 141.
Cassidulus zquoreus D’Orbigny, 1847, Prodrome, vol. 2, p. 271.
Cassidulus xquoreus Bronn, 1848, Index palzontologicus, vol. 1, p. 244.
Cassidulus xquoreus D’Orbigny, 1853-60, Paléontologie frangaise, vol. 6, p. 329, Pl. CMX XVI, figs. 6-12.
Cassidulus xquoreus Desor, 1858, Synopsis des échinides fossiles, p. 290.
Cassidulus zquoreum Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 15.
Cassidulus xquoreus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 2.
Cassidulus xquoreus Conrad, 1868, Geology of New Jersey, App. A, p. 722.
Cassidulus xquoreus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 7
Cassidulus equoreus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 5
Cassidulus equoreus Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 68, 69, Pl. X.XIX, figs. la-i.
Cassidulus xquoreus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.
Cassidulus xquoreus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 293-294, Pl.
XII, figs. 5-12.

Determinative characters—Test subpentagonal, depressed; upper surface convex; under
surface concave, slightly rostrated posteriorly; apex forward of the center. Ambulacra narrow;
poriferous zones petaloidal on the upper surface; contracted above the margin and expanded
again on the lower surface, much narrowed at the peristome. Interambulacra wide, covered
with small perforated tubercles. Apical system small, situated forward of the center. Peris-
tome small, with floscelle. Periproct supramarginal, in short sulcus.

Dimensions.—Typical form: Length 31.25 miulimeters; width 28.12 millimeters; height
15.6 millimeters.

Description.—This typical Cassidulus, early recognized as such by Morton, has a depressed
test, subpentagonal in outline. It is longer in the anteroposterior diameter than the lateral.
The upper surface is convex, with sharp marginal edges, while the lower surface is flat, with a
slight coneavity toward the center. The apex is somewhat anterior to the center.

6.
2.

76 MESOZOIC AND CHNOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacra are narrow. The poriferous zones are uniserial, the pores of the upper part
of the aboral surface arranged in petaloidal form. Ata point varying in the different areas from
one-quarter to one-third of the distance from the margin to the apical system the zones are con-
tracted and continue as narrow bands over the margin and to the vicinity of the peristome, where
they broaden again perceptibly, becoming finally much contracted at the margin of the oral
opening. The pores are distinct in the petaloidal portion and in the broadened area near the
peristome but in the intermediate contracted portion are small and ‘indistinct. The interam-
bulacra are broad and covered by small perforated tubercles with sunken areolas.

The apical system is composed of four perforated genital and five small ocular plates. As
explained under the previous species, the fifth genital is obsolete.

The peristome is pentagonal and surrounded by a well-developed floseelle. The oral lobes
are very prominent and the ambulacral furrows much contracted.

The periproct is situated in a short sulcus on the upper surface. .

Related forms.—This species is separated from (. florealis by its more depressed and elon-
gated form. From @. micrococcus it is separated by its sharper apex, more angular margin, the
position of its periproct, and the shorter pore openings in its outer rows.

Localities. —Prairie Bluff, Ala. (type); bluff east of Atlantic Highlands, N. J.

Geologic horizon —Navesink marl of Monmouth group, New Jersey, and Ripley formation,
Alabama; Upper Cretaceous.

Collection —Academy of Natural Sciences of Philadelphia (1475).

CaAssIDULUS MICROCOCCUS Gabb.
Plate XXXI, figures lao.

Cassidulus micrococcus Gabb, 1860, Acad. Nat. Sci. Philadelphia Proc., p. 519.

Cassidulus micrococcus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.
Cassidulus micrococcus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Cassidulus micrococcus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 69, 70, Pl. XXX, figs. la.
Cassidulus micrococcus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Determinative characters —Test oval, rounded anteriorly, slightly rostrated posteriorly;
upper surface convex, flattened at the apex; sides equally declining. Ambulacra moderately
broad; poriferous cones petaloidal on dorsal surface; outer row of pores slitlike in petaloidal
portion. Peristome small, pentagonal, with floscelle. Periproct oval, situated high on upper
surface, in long, narrow sulcus.

Dimensions.—Length 45 millimeters; width 42 millimeters; height 21.5 millimeters.

Description.—This species has a distinctly oval form, wider posteriorly. The upper surface
is elevated at the margin but somewhat flattened at the apex. The sides decline very nearly
equally. The base is flattened, with a slight concavity at the peristome. The posterior margin
is truneated and slightly rostrated.

The ambulacra are rather broad, contracted about one-quarter of the distance from the
ambitus to the apex, and narrowed nearly to the peristome, where they are again broadened to
form indistinct phylloidal areas. The pores are slitlike in the outer rows of the petaloidal
portion. :

The interambulacral plates are covered with minute tubercles, with sunken areolas, that
increase in size and number of the oral surface.

The apical system is situated slightly in front of the upper surface, in a long, narrow, and
deep sulcus.

Related forms.—A comparison of this species with Cassidulus zquoreus, as made also by Gabb
in his original description, shows that it is much larger and more oval, and that its periproet is
situated higher and in a deeper and longer suleus, and, furthermore, that the pores of the outer
row in its petaloidal portion are elongated and slitlike.

Locality.— Eufaula, Ala.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection. —Academy of Natural Sciences of Philadelphia (1480).

CRETACEOUS ECHINODERMATA. 717

CASSIDULUS SUBQUADRATUS Conrad.
Plate XX XI, figures 2a-c.

Cassidulus subquadratus Conrad, 1860, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 4, p. 291, Pl. XLVII, fig. 19.
Cassidulus subquadratus A. Agassiz, 1883, Mus. Comp. Zool. Mem., vol. 10, p. 90.

Cassidulus subquadratus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.

Cassidulus subquadratus Clark, 1893, Johns Hopkins Uniy. Cire., vol. 12, No. 103, p. 52.

Cassidulus subquadratus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 70, 71, Pl. XXXT, figs. la—h.

Cassidulus subquadratus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Cassidulus subquadratus Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, No. 1, pp. 5, 6.

Determinative characters.—Test subquadrate to subpentagonal, hemispherical; sides equally
declining, upper surface convex; lower surface concave; posterior margin truncated and ros-
trated. Poriferous zones broadly petaloidal on upper two-thirds of the dorsal surface; sharply
contracted at lower margin of petaloidal areas. Peristome small, pentagonal, with well-defined
floscelle. Apical system large, shghtly anterior to the center. Periproet round, in deep sulcus.

Dimensions.—Length 56.5 millimeters; width 53 millimeters, height 28 millimeters.

Description.—This remarkably symmetrical Cassidulus has a nearly hemispherical form.
In outline it is nearer subpentagonal than subquadrate, owing to the rostrated character of the
posterior margin, which is at the same time truncated. The anterior margin is rounded. The
lateral edges are nearly parallel, though somewhat more approximated anteriorly. The apex is
slightly forward of the center.

The ambulacra are moderately wide in the petaloidal portion, narrow beyond. — The porif-
erous zones are composed in the petaloidal portion of an inner row of small, nearly circular pores
and of an outer row of oblique slitlike openings. The pores of each pair are united by a shallow
furrow. Beyond the petaloidal areas the narrow plates of those portions give place to broad
plates, each with a pair of small, round pores in the lower and outer corner. In the vicinity of
the peristome the poriferous zones expand and the pores increase in size, though apparently
reduced in number. The last pair of plates are much contracted. |

The interambulacra are wide. The plates are covered with minute tubercles with depressed
areolas, which become larger and more prominent on the lower surface.

The apical system is large, composed of four perforated genital and five ocular plates. The
fifth genital is apparently obsolete.

The peristome is small, pentagonal, end surrounded by a well-developed floscelle. The
periproct is round and is situated high above the margin, in a deep sulcus, that becomes narrower
and shallower toward the ambitus.

Related forms.—This species is most closely related to Cassidulus subconicus, but the latter
is much more elevated and has its periproct-situated higher and in a less depressed sulcus.

Locality.—Near Holly Springs, Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection.—U. S. National Museum (31200).

CassipuLUs suBconicus Clark.
Plate XXXII, figures la-k.

Cassidulus subconicus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.
Cassidulus subconicus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Cassidulus subconicus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 71, 72, Pl. XXXII, figs. la-k.

Determinative characters.—Test subconical; margin subpentagonal, truncated and rostrated
posteriorly; apex anteriorly placed. Ambulacra broad in petaloidal areas. Apical system
large, anteriorly situated. Peristome subcireular, with very prominent floscelle. Periproct
large, situated high on upper surface, in shallow sulcus.

Dimensions.—Length 47 millimeters; width 43 millimeters; height 27.5 millimeters.

Description.—The test is subconical. In marginal outline it is subpentagonal, the pos-
terior border more or less rostrated and clearly truncated. The apex is slightly forward of the
center, giving a somewhat sharper slope to the anterior portion of the test than to the posterior.

39800°—15 6

78 . MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacra are broad in the petaloidal portion, beyond which they are narrowed. At
the margin they again acquire considerable width but gradually contract beyond, although
expanded for a short distance in the phylloidal area near the peristome. At the peristome the
final pair of plates is highly attenuated. The pores of the outer rows, in both the petaloidal and
phyloidal areas, are in a marked degree elongated. In the intermediate portion of the column
they are small and indistinct.

The interambulacra are more prominent than the ambulacra, which are slightly depressed.
The surface is covered with minute tubercles and a microscopic granulation.

The apical system is large, subcircular, and surrounded by a very prominent floscelle. The
periproct is large, circular, and is situated high above the margin in a shallow suleus.

Related forms.—C. subconicus is closely related to C. subquadratus but is separated from it
by its high subconical test, more elevated periproct, and shallow anal sulcus.

Locality —Dumas, Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Oollection.—U. S. National Museum (20264).

CAssIDULUS PORRECTUS Clark.
Plate XXXII, figures 2a-b; Plate XX XIII, figures la-f.

Cassidulus porrectus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76. -

Cassidulus porrectus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Cassidulus porrectus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 72, 73, Pl. XX XIII, figs. la-b, Pl. XXXIV, figs. la-b.,
Pl. XXXYV, figs. la-d.

Determinative characters.—Test very large, subcircular, oval, depressed; upper surface con-
vex; lower surface concave; broader posteriorly than anteriorly; apex forward of the center.
Ambulacra broad. Interambulacra thickly covered with minute tubercles. Apical system
small, forward of the center. Peristome large, subconical, with prominent floscelle. Periproct
supramarginal, in short shallow sulcus.

Dimensions.—Length 99.6 millimeters; width 97.5 millimeters; height 44.5 millimeters.

Description.—This very large Cassidulus has an irregularly oval, depressed test, that is sub-
circular in marginal outline. The width is equal to the length but is greatest in the posterior
portion, so that the margin appears contracted anteriorly. The apex is some distance forward of
the center and slightly flattened. The posterior margin is feebly truncated.

The ambulacra are wide; the contractions below the petaloidal region and above the phyl-
loidal continue for short distances, while the lowest pair of plates in the column bordering the
peristome are long and greatly attenuated. The pores of the outer rows are slitlike in form and
obliquely placed.

The interambulacra are prominent; the plates are covered with numerous small tubercles,
with depressed areolas, which are larger and more prominent on the under than the upper surface.
The apical system is small and is placed forward of the center. -

The peristome is large, subcircular, with very prominent floscelle. The oral lobes project
far beyond the level of the base and are separated by deep ambulacral furrows.

The periproct is large, oval, and is situated at the head of a short, narrow sulcus.

Related forms.—C. porrectus is from its size, form, and details of structure readily separated
from the other species of Cassidulus described from the American and European Cretaceous.

Locality —Eufaula, Ala.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection.—U. S. National Museum (21890).

CRETACEOUS ECHINODERMATA. 79
CASSIDULUS STANTONI Clark.
Plate XX XIII, figures 2a-d.

Cassidulus stantoni Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 76.
Cassidulus stantoni Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Cassidulus stanton Clark, 1893, U. S. Geol. Survey Bull. 97, p. 73, Pl. XX XV, figs. 2a-d.

Determinative characters—Test small, subovate, elevated; upper surface convex, lower
surface concave; apex forward of the center. Ambulacra very narrow. Apical system small,
forward of the center. Peristome small, with floscelle. Periproct high above margin, in long,
narrow, and deep sulcus.

Dimensions.—Length 15 millimeters; width 14 millimeters; height 6.5 millimeters.

Description.—This minute Cassidulus has a subovate test, an elevated convex upper sur-
face, and a concave lower surface. It is broader posteriorly than anteriorly, and its posterior
margin is truncated. The apex is situated slightly anterior to the center of the upper surface.

The ambulacra are very narrow. The petaloidal portion but slightly exceeds the remainder
in width, which is nearly equal throughout. The phylloidal region is feebly outlined.

The interambulacra are broad, but the poor state of preservation of the specimens renders
it impossible to determine ail the details of structure.

The apical system is small and forward of the center, but not sufficiently well preserved
to distinguish the individual plates. The peristome is small and surrounded by a feeble flos-
celle. The periproct is round and situated high above the margin, at the head of a narrow deep
sulcus.

Related forms.—C. stantoni is quite unlike any other representative of this genus from Ameri-
can strata and can not be readily associated with any European species.

Locality —Muddy Creek, Huerfano County, Colo.

Geologic horizon.—Colorado group, Upper Cretaceous.

Collection —U. S. National Museum (20260).

CASSIDULUS INTERMEDIUS Slocum.
Plate XXXIV, figures la-f.

Cassidulus intermedius Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, No. 1, pp. 6, 7, Pl. I, figs. 1-6.

Determinative characters.—Test oval, depressed, rounded anteriorly, slightly rostrated pos-
teriorly. Apex excentric anteriorly. Ambulacra narrow. Peristome large, slightly in front
of center of ventral surface. Periproct on upper surface, about one-third of the distance from
the apex to the margin, in broad deep sulcus.

Dimensions.—Type specimen: Length 25.6 millimeters; width 22.7 millimeters; height 9.6
millimeters.

Slocum says:

Description.—Test oval, greatest width posterior to the center; rounded anteriorly, slightly rostrated posteriorly ;
dorsal surface convex, apex excentric anteriorly and inflated, sides declining about equally towards the margins which
are slightly inflated; the peristomal concavity occupying more than half of the central surface. Ambulacral areas nar-
row and flush, poriferous zones subpetaloidal on the upper part of the dorsal surface to a point varying in the different
areas from about one-third to nearly one-half the distance from the margin to the apical system; the zones are then con-
tracted and continue as narrow bands over the margin to the vicinity of the peristome, where they abruptly widen,
and gain narrow to the peristome forming a floscelle. The pores are distant and paired on the petaloid portion and in
the floscelle; on the narrow connecting portions they are single, small and indistinct. In the petaloid areas the pores
of the outer rows are slitlike, those of the inner row round and smaller; each pair is connected by a groove. Inter-
ambulacral areas composed of large plates, the plates nearest the peristome in each area inflated forming the bourrelets.
Dorsal surface covered with small crowded tubercles with slightly sunken areoles, the tubercles on the ventral surface
rapidly increasing in size and distance apart as they approach the peristome. A wide, longitudinal median band extends
from near the anterior margin through the floscelle to the posterior margin. This band is without tubercles and the
surface is smooth except where it passes through the floscelle. The apical system in the type specimen is too incomplete
for detailed description, but appears similar to other species of this genus. The peristome is situated slightly in front of
the center of the ventral surface, pentagonal, surrounded by a well-marked floscelle, the bourrelets large and prominent,

©

80 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

the phyllodes very narrow as they reach the peristome and situated in grooves. The periproct is elongated longitudi-
nally and situated on the dorsal surface about one-third the distance from the posterior margin to the apex in a deep
groove.

Related forms.—In general form this species resembles C. xquoreus, but is not so high in proportion to its length, the
periproct is somewhat higher, the pores in the outer rows of the petaloid portions are slitlike instead of round, and the
expansions of the phyllodes are wider. C. intermedius resembles C’. micrococcus in the slitlike pores of the outer rows
of the petaloid areas and in the expansion of the phyllodes, but the position of the pores in these expansions is more
like those of C. xquoreus. The position of the periproct is midway between that of C. micrococcus and C. equoreus, the
size and shape of the test is quite unlike C. micrococcus and the extension of the longitudinal median band in front of
the peristome on the ventral suriace does not appear, from the description and figures, to occur in either of the other
species. The name adopted for this species refers to the characters intermediate between C. equoreus and C. micrococ-
cus which the species exhibits.

Locality.—Near the southern edge of the village of Pontotoc (Slocum), Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous. j
Collection.—Field Museum of Natural History (P 10346).

CASSIDULUS HEMISPHERICUS Slocum.

Plate XXXIV, figures 2a-c.
Cassidulus hemisphericus Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, Nc. 1, pp. 7, 8, PI. I, figs. 7-9.

Determinative characters.—Test subhemispherical, elevated, margins angular, lower surface
flat. Ambulacra wide. Peristome nearly central. Periproct supramarginal.
Dimensions.—Type specimen: Length 34.7 millimeters; width 26.7 millimeters; height
19.5 millimeters. Allowing for the lateral crushing it is probable that the length and width
were originally about 32 millimeters and 29 millimeters, respectively.
Description—Slocum says:
Test subhemispherical with its transverse diameter somewhat shorter than the longitudinal, sides arcuate, margins
angular, ventral surface flat or nearly so. Ambulacral areas wide, subpetaloidal on the top of the dorsal surface, not
closed distally, petals subequal in length, extending about halfway from the apex to the margin, slightly convex; from
the distal end of the petals the ambulacral areas are continued as a band which gradually fiaarenzadl in width from the
petal to the margin, most of the way being wider than the petal. On the ventral surface the bands slightly narrow to
the floscelle. The floscelle is not well preserved in the type specimen, but enough is preserved to determine that the
bourrelets are prominent and that the phyllodes are in grooves. The apical system is central but the form of the various
plates of which it is composed can not be determined. The interambulacral areas are about equal in size. They form
an acute angle near the apex and rapidly expand to the margin, the plates being comparatively large. All the plates
of the dorsal surface, with the exception of those of the petals, are marked by prominent lines subparallel to the edge
of the plates. These lines are farther apart on the lateral edges than on the proximal and distal edges. They appear
to be lines of growth. The middle portion of the plates within this series of lines is inflated, so that in the small plates
of the interambulacrai areas, near the apex, the centers of the plates appear as prominent nadie, These middle portions
of the plates are free from tubercles, but the parts of the plates covered by the parallel lines and the plates of the petals
are covered with minute tubercles closely crowded together. The lines are much less prominent on the plates of the
ventral surface and the tubercles are larger, with slightly sunken areoles, and more evenly distributed over the surface,
except on the longitudinal median band, which extends from the peristome to the posterior margin. The peristome is
situated at the center of the ventral surface, surrounded by a floscelle, the bourrelets are prominent, and the phyllodes
are depressed and contracted into narrow grooves where they reach the peristome. The periproct is supramarginal,
but its form and exact position are unknown, because that portion of the posterior interambulacral area near the margin
is missing.
Locality.—The ‘‘white gullies” on the Patterson farm, about 3 miles south of Pontotoc,
Miss.
Geologic horizon.—Ripley formation, Upper Cretaceous.
Collection.—Field Museum of Natural History (P 10347).

CASsIDULUS CONOIDEUS Clark, n. sp.
Plate X XVII, figures 3a-d.

Determinative characters —Test moderate, nearly circular, inflated above, flat below.
Apical system excentric anteriorly. Ambulacra nearly similar, subpetaloid. Peristome excen-
tric forward. Periproct supramarginal in poorly defmed groove.

Dimensions.—Length 31.5 millimeters; width 52 millimeters; height 28 millimeters.

\ CRETACEOUS ECHINODERMATA. 81

Deseription.—This species has a test of moderate size, nearly circular and much elevated.
The apex is near the center of the upper surface. The upper surface is convex, the lower nearly
flat.

The ambulacra are wide, nearly similar, distinctly petaloidal above. The interambulacra,
are prominent, projecting slightly above the ambulacra.

The peristome is of small size and excentric forward. The periproct is small, supramar-
ginal and located m a very poorly defined groove. The material of the test has been destroyed,
only a cast remaining.

Locality —Pataula Creek, Clay County, Ga.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection.—U. 8. National Museum (31199).

CaSSIDULUS ABRUPTUS Conrad.

Cassidulus abruptus Conrad, 1860, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 4, p. 291.
Cassidulus abruptus Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 90.

(2) Cassidulus abruptus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

(2) Cassidulus abruptus Clark, 1893, U. S. Geol. Survey Bull. 97, p. 92.

This species, originally described by Conrad in 1860, but not figured, has not been recog-
nized in material examined by the writer, so that its relations to the other forms described are
not known.

Locality.—Tippah County, Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collection —Unknown.

?CASSIDULUS SUBANGULATUS (Emmons).

Gonioclypeus subangulatus Emmons, 1858, North Carolina Geol. Survey Rept., p. 309, figs. 242, 243.
Gonioclypeus subangulatus Conrad, 1866, Check list, p. 31.

This species, which is described from the ‘Eocene, Wadsworth marl, Craven County,”
N. C., by Emmons is probably a Cretaceous form and if the strata in which it was found are
Eocene was doubtless mechanically transported from older deposits. It is apparently identical
with C. subquadratus Conrad, but as its type form is unknown and no further material has been
found it seems wiser to maintain the separation of the two species until more positive data are
secured.

Locality.—Craven County, N. C.

Geologic horizon.—Peedee sand (?), Upper Cretaceous.

Collectton— Unknown.

Suborder STERNATA.

Family ECHINOCORYTHID®.
Genus ANANCHYTES Mercati.

ANANCHYTES OVALIS Clark.
Plate XX XV, figures la-h.

Ananchytes ovalis Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 1038, p. 52.

Ananchytes ovalis Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 74, 75, Pl. XXXVI, figs. la-h.

Ananchytes ovalis Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, p. 295, Pl.
XIII, figs. 1-8.

Determinative characters—Test medium sized, subovate cordate; contracted posteriorly;
upper surface convex; lower surface flat. Apical system elongated, consisting of four perfo-
rated genital and five ocular plates situated slightly forward of the center. Peristome near the
anterior margin. Periproct oval, situated on a slight protuberance of the posterior margin.

82 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions.—Length 43.75 millimeters; width 37.5 millimeters; height 31.25 millimeters.

Description The specimens of this species collected by the writer are remarkably well pre-
served and admit of the determination of all the essential features. The test is in lateral outline
subovate, though somewhat cordate in form when viewed from above or below. A marked pro-
tuberance is present on the posterior margin that appears as a slight ridge on the lower surface
between the peristome and periproct. The upper surface is convex. The sides are full and
rounded at the ambitus. The base is nearly flat, with the exception of the slight ridge and
depressed peristome.

The ambulacra are wide and straight, attaining their greatest width just above the ambitus.
The pores are oval, and those of each pair are placed toward the ambitus at an angle to one
another. The surface of both the ambulacral and interambulacral plates is covered by small
tubercles, between which are numerous microscopic granules. The apical system is elongated.
The four genital plates are large and distinctly perforated. The anterior, right-hand genital
plate, which serves as the madreporite, is much larger than any of the others, being several times
the size of the anterior left-hand genital, with which it is in contact. The posterior genitals are
very nearly of equal size. :

The peristome is transversely oblong and situated near the anterior margin. The periproct
is oval and situated on a marked protuberance on the posterior margin.

Locality.— Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collection —Johns Hopkins University (T 3011).

ANANCHYTES TEXANA Cragin.

Plate XX XV, figures.2a-c; Plate XXXVI, figures la—b.

Ananchytes texana Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 145, 146, Pl. XX VI, figs. 1, 2, Pl. XXV,
fig. 12.

Determinative characters.—Test large, high, oval in marginal outline, rounded anteriorly,
narrowed posteriorly; upper surface convex, lower surface flat; ambulacra flush, nearly alike,
apetalous pair of pores more strongly developed on upper surface; interambulacra with large —
plates covered with few primary tubercles and many granules; peristome far in front; periproct
well forward on lower surface.

Dimensions.—Length 107 millimeters; width 87 millimeters; height 68 millimeters.

Description —Cragin says: \

Large conico-hemispherical as seen from the side; plan ovate, wider anteriorly; peristome of moderate size, trans-
verse, oblong-reniform, the anterior lip and immediately contiguous surface deeply and abruptly depressed, the
remainder of the interior surface slightly depressed, the depression being posteriorly parted by a gentle median undu-
lation that includes the periproct and becomes gradually obsolete a short distance in advance of it; periproct infra-
marginal and relatively smaller than in most (if not all) other known species of the genus, rather narrowly ovate and
posteriorly more or less pointed; anterior ambulacrum about two-thirds as wide as either of the adjacent interambula-
cra, ambulacral plates very numerous and narrow, averaging about a millimeter in width on the greater part of the zone;
the pores rounded but usually more or less transversely elongated, the line connecting the pores of one pair being hori-
zontal except in the case of a few of the lower pairs; surface nearly even, the principal tubercles rather small and not
very prominent.

Locality.—Two and one-half miles northwest of D’Haniss, on Seco Creek, Medina County,
Tex. (type); White Cliffs, Ark.

Geologic horizon.—Austin chalk and Annona chalk, Upper Cretaceous.

Collections.—Geological Survey of Texas; Johns Hopkins University.

CRETACEOUS ECHINODERMATA. 83
Genus CARDIASTER Forbes.
CARDIASTER cINcTUS (Morton).
Plate XXXVI, figures 2a—h.

Spatangus sp. Morton, 1829, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 6, p. 122.

Ananchytes sp. Morton, 1830, Am. Jour. Sci., Ist ser., vol. 17, p. 287.

Ananchytes cinctus Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, p. 200.

Ananchytes fimbriatus Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 6, p. 200.

Ananchytes cinctus Morton, 1830, Am. Jour. Sci., Ist ser., vol. 18, p. 246, Pl. III, fig. 7.

Ananchytes fimbriatus Morton, 1830, Am. Jour. Sci., Ist ser., vol. 18, p. 245, Pl. III, fig. 9.

Ananchytes cinctus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 78, Pl. IIT, fig. 19.

Ananchytes fimbriatus Morton, 1834, Synopsis Organic Remains Cretaceous, pp. 77, 79, Pl. III, fig. 20.

Holaster cinctus Agassiz and Desor, 1840, Catalogue systématique, p. 1.

Holaster cinctus Agassiz and Desor, 1847, Catalogue raisonné, p. 133.

Holaster fimbriatus Agassiz, 1847, Catalogue raisonné, p. 141.

Holaster cinctus D’Orbigny, 1847, Prodrome, vol. 2, p. 269.

Holaster fimbriatus D’ Orbigny, 1847, Prodrome, vol. 2, p. 269.

Holaster cinctus Bronn, 1848, Index paleontologicus, vol. 1, p. 593.

Ananchytes fimbriatus Bronn, 1848, Index palzeontologicus, vol. 1, p. 70.

Cardiaster cinctus Bronn, 1853-1856, Lethzea geognostica, vol. 2, pt. 5, p. 205.

Cardiaster cinctus D’ Orbigny, 1853-1860, Paléontologie francaise, vol. 6, p. 147; Pl. CMXCV, fig. 4.

Cardiaster fimbriatus D’ Orbigny, 1853-1860, Paléontologie frangaise, vol. 6, p. 147; Pl. CMXCV, fig. 3.

Cardiaster cinctus (Cardiaster fimbriatus) Desor, 1858, Synopsis des échinides fossiles, p. 346.

Ananchytes cinctus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.

Ananchytes fimbriatus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 18.

Holaster cinctus Credner, 1870, Deutsche geol. Gesell. Zeitschr., vol. 22, p. 218.

Holaster cinctus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Cardiaster cinctus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p.52. *

Cardiaster cinctus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 75, 76, Pl. XX XVII, figs. la—h.

Cardiaster fimbriatus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Cardiaster cinctus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Cardiaster cinctus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 296-297, Pl. XVI,
figs. 1-8. ‘ :

Determinative characters.—Test large, cordate, distinctly grooved anteriorly; contracted
posteriorly; upper surface convex; lower surface flat. Ambulacra wide. Apical system much
elongated, consisting of four perforated genital and five ocular plates situated slhghtly forward
of the center. Peristome near the anterior margin. Periproct oval, situated on the truncated
posterior margin.

Dimensions.—Length 30 to 60 millimeters; width 25 to 55 millimeters; height 20 to 30
millimeters. a

Description.—This species, which is among the earliest of the Echinoid forms recognized
from American Cretaceous strata, is distinctly cordiform, with a pronounced groove on the
anterior face that is occupied by the unpaired ambulacrum. Opposite thereto is a slight ridge
at the central suture of the unpaired posterior interambulacrum which is suddenly terminated
by the nearly vertically truncated surface of the posterior margm. The sides decline equally to
the ambitus, giving an oval outline to the vertical lateral section. The lower surface is nearly »
flat, with the exception of the slight depressions directly at the mouth edges and the elevated
area extending from the center of the base to the posterior margin.

The ambulacra are wide, apetaloid, and separated at the apex. The anterolateral pair are
bent backward in their upper part, beyond which they extend straight to the margin. The
postero-lateral pair are bent somewhat forward, after which they extend straight over the margin.
The single ambulacrum is situated in the deep anterior sulcus. The pores of the paired ambu-
lacra consist, in the upper portion of the columns, of oblique oval openings united by furrows
while lower down they become small and often indistinct. In the unpaired ambulacrum the
pores are extremely small.

The surface of the interambulacral as well as of the ambulacral plates is covered with fine
granules, among which are irregularly scattered numerous small perforated tubercles.

84 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The apical system is narrow, elongated. The four perforated genital plates are disposed in
pairs, between which two of the five ocular plates are situated. Forming the posterior portion
of the disk are two more ocular plates, while the fifth plate comprises the anterior part. The
ambulacral areas are on this account separated at their apices.

The peristome is transversely oblong and is situated near the anterior margin of the base.
The periproct is oval and situated on the truncated surface at the posterior margin of the test.

Localities —Vincentown and Timber Creek, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections —Academy of Natural Sciences of Philadelphia (1485); American Museum of
Natural History, New York.

CARDIASTER SMOCKI Clark.

Plate XXXVI, figures 3a-c.

Cardiaster smocki Clark, 1907; Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, p. 298, PI.
XIII, figs. 9-11.

Determinative characters —Test cordiform, elevated, with deep anterior sulcus; upper sur-
face convex; lower surface flat. Ambulacra wide. Apical system elongated. Peristome near
the anterior margin.

Dimensions —Length 25 millimeters; width 23 millimeters; height 14 millimeters.

Description—The test is small, distinctly elevated, with strongly convex upper surface.
The anterior ambulacral sulcus is very pronounced, and the opposite ridge in the unpaired pos-
terior interambulacrum is well shown but is sharply cut off by the nearly vertically truncated
surface of the posterior margin. The sides slope rapidly to the ambitus, which is sharp and cor-
date in outline. The lower surface is nearly flat.

The ambulacra are wide, apetaloid, and well separated at the apex. The anterolateral pair
are bent backward above, beyond which they extend straight to the ambitus. The postero-
lateral pair are bent slightly forward, beyond which they continue in a straight line over the
margin. The unpaired ambulacrum is situated in the deep anterior sulcus.

The apical system is much elongated, widely separating the ambulacral area8.

The peristome is situated anteriorly and is transversely oval.

Related forms.—This species is most closely related to Cardiaster cinctus but is smaller and
has a somewhat less pronounced anterior sulcus and a more inflated test.

Locality.—Two and a half miles northwest of Matawan, N. J.

Geologic horizon.—Merchantville clay of Matawan group, Upper Cretaceous.

Collection —Geological Survey of New Jersey.

CARDIASTER cURTUS Clark, n. sp.
Plate XX XVII, figures la—h.

Determinative characters.—Test small, cordate, high anteriorly, clearly marked anterior
groove with well-defined keel on either side; ambulacra wide, interambulacra with large plates;
peristome near posterior margin.

Dimensions —Length 22 millimeters; width 19 millimeters; height 12 millimeters.

Description.—The two specimens of this small species are fragmentary although retaming
the most important characteristic portions.

The test is cordate, elevated toward the posterior margin and with broad and deep anterior
groove. The ambulacra are broad, the poriferous zones are clearly marked on the upper sur-
face. The pore pairs are oval above and more nearly round toward the ambitus. The surface
of the plates is covered by minute granules.

The interambulacra are composed of large plates covered with minute granules.

The apical system is elongate, the four genitals varying in shape and size. The two antero-
lateral oculars are very large and separate the antero-lateral from the postero-lateral genitals
which are in contact, the latter isolating the two postero-lateral oculars from the remainder of the
apical system.

CRETACEOUS ECHINODERMATA, 85

The peristome is near the posterior margin. The periproct is not preserved.
Locality —Twenty-five miles southwest of Mingusville (now Wibaux), Mont.
Geologic horizon.—Fox Hills (?) sandstone of Montana group, Upper Cretaceous.
Collection.—U.S. National Museum (31201).

Genus HOLASTER Agassiz.
HOLASTER SIMPLEX Shumard.
Plate XXXIV, figures 3a-b; Plate XX XVIII, figures la-j; Plate XX XIX, figures la-g.

Holaster simplex Shumard, 1853, Pal. Expl. Red River of Louisiana in 1852, p. 210, Pl. III, fig. 2.

Holaster comanchesi Marcou, 1858; Geology of North America, p. 40, P]. III, fig. 3.

Holaster simplex Desor, 1858, Synopsis des échinides fossiles, p. 450.

Holaster comanchesi Desor, 1858, Synopsis des échinides fossiles, p. 449.

Holaster simplex Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Holaster comanchesi Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Holaster simplex Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Holaster comanchesi Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Holaster simplex Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Holaster simplex Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Holaster simplex Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 76-78, Pls. XXVIII, figs. la-g; Pl. XX XIX, figs. la-d.

Holaster completus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 155, 156, Pl. XXIV, fig. 10; Pl. XXV,
fig. 14; Pl. XXVI, figs. 6-8.

Holaster nanus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 156, Pl. XXIV, fig. 14; Pl. X XVI, fig. 11.

Holaster simplex Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 157, Pl. XXV, fig. 13.

Holaster supernus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 157, 158.

Holaster completus Cragin, 1894, Colorado Coll. Studies, vol. 5, pp. 45, 47.

Holaster nanus Cragin, 1894, Colorado Coll. Studies, vol. 5, pp. 45, 47.

Determinative characters—Test oblong, cordiform; upper surface much elevated, rounded,
and grooved on the anterior face; lower surface flat; apex nearly central. Ambulacra wide;
pores unigeminal, with slitlike openings in the upper portion of the column that become indis-
tinct toward the margin and upon the base. Apical system compact and not greatly elongated.
Peristome transversely oval, situated near the anterior margin. Periproct large, on truncated
posterior margin.

Dimensions —Length 32 to 70 millimeters; width 30 to 60 millimeters; height 14 to 53
millimeters.

Description —The test is oblong, cordiform, much elevated, rounded above and flattened
below. A shallow groove occupies the anterior face of the test, producing a feeble emargination
of the anterior ambitus. A slight ridge extends along the line of the central suture of the single
interambulacrum, which is suddenly terminated by the truncated face of the posterior margin.

The ambulacra are wide. The poriferous zones of the paired ambulacra are in the case
of the posterior pair bent more or less forward in their upper portions, and in the case of the
anterior slightly backward. The pores of the paired ambulacra have elongated openings in the
upper portion and become very small and indistinct below. The pores of the unpaired ambula-
crum are exceedingly small.

The surface of both interambulacraleand ambulacral plates are covered by small tubercles,
between which are numerous microscopic granules.

The apical system is compact and rather short. The four genital plates are large and
broad. The two interposed oculars are large, the remaining three very small.

The peristome is large, transversely oblong, and situated near the anterior margin. The
periproct is oval, acuminate above, and situated on the truncated posterior border.

The variations in this species are very pronounced, some of the individuals being high and
globose and others low and flat. A critical examination of a large number of specimens affords
no satisfactory criteria for the recognition of the new species established by Marcou and Cragin.

Related forms.—H. simplex is very like H. levis var. planus, from the European Cretaceous,
but is more elevated and distinctly broader posteriorly.

86 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Localities.—Fort Washita (type), Bexar County (figured specimen A), near Fort Worth, at
Preston, Grayson County (figured specimen B), on the Red River, near Austin, and near El Paso,
Tex.; near Fort Washita, Okla.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.
2A); Geological Survey of Texas (B); Johns

Hopkins University.
Family SPATANGID®.

Genus ENALLASTER D’Orbigny.
ENALLASTER TEXANUS (Roemer).
Plate XX XIX, figures 2a-g.

Toxaster texcanus Roemer, 1849, Texas, p. 393.

Toxaster texcanus Roemer, 1852, Die Kreidebildungen von Texas, pp. 85, 86, PL. X, fig. 3

Toxaster ungula Giebel, 1853, Naturwiss. Ver. in Halle Jahresb., p. 373.

Enallaster texanus iD Onetan, 1853-60, Paléontologie frangaise, vol. 6, p. 184, Pl. DCCCL, figs. 1-7.

Toxaster texcanus Conrad, 1857, U. 8S. and Mex. Boundary Survey Rept., vol. 1, pt. 2, p. 145, Pl. I, figs. 2a-c.
Enallaster texanus Desor, 1858, Synopsis des échinides fossiles, p. 358.

Toxaster texanus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Toxaster texanus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Enallaster tecanus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Enallaster tecanus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Enallaster texanus Clark, U.S. Geol. Survey Bull. 97, pp. 78, 79, Pl. XX XIX, figs. 2a-g.

Enallaster inflatus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., pp. 150, 151, Pl. XXIV, fig. 13.
Enallaster tecanus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 151.

Enallaster texanus Cragin, 1894, Colorado Coll. Studies, vol. 2 p. 41.

Enallaster inflatus Cragin, 1894, Colorado Coll. Studies, vol. 5, pp. 45, 47.

Enallaster tecanus Hill and Vaughan, 1898, U. 8. Geol. cee Eighteenth Ann. Rept., pt. 2, Pl. LIII, figs. 4a-b.
Enallaster texanus Hill, 1901, U.S. Geol. Survey Twenty-first Ann. Rept., pt. 7, p. 226, Pl. X XVII, figs. 4a—-b.
Enallaster sp. Hill, 1901, U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, p. 283.

Determinative characters —Test oblong, cordiform, broad in anterior portion, contracted
and truncated posteriorly, with deep anterior groove; upper surface convex, elevated; base flat,
depressed at the peristome; sides rounded; apex excentric and posterior. Ambulacra narrow
and unequal, the posterolateral pair much shorter than the others. Apical system small and
compact. Periproct situated high above the margin.

Dimensions.—Length 16 to 45 millimeters; Saath 14 to 38 millimeters; height 9 to 27
millimeters.

Description.—The test is oblong, cordiform, and elevated. The upper surface is convex,
with a well-defined anterior groove, narrow and slightly depressed at its head. On the posterior
face the surface is truncated to the margin. The sides are rounded and inflated. The base is
flat, except for the peristonal depression near the anterior margin and the central elevated region
extending from the same to the posterior border.

The ambulacra are narrow and very unequal. The antero-lateral pair are large and curved
backward in their upper portions. The pores are very unequal; those of the anterior zone are
small and near together, those of the posterior elongated, the outer nearly twice as large as the
inner series. ‘There are about thirty-five pairs of pores in the petaloidal portion of each poriferous
zone.

The postero-lateral pair are short and quite symmetrical in structure. There are sixteen
pairs of pores in the petaloidal portions of each poriferous zone.

The anterior unpaired ambulacrum is situated in the anterior groove and is wider than the
other areas. An elongated pore appears in the external rows on alternate plates. On the inter-
vening plates the small rows are closely approximated. In the lower portion of each column the
plates are large and oblong. A pair of minute pores occupies the lower outer corner of each.

The surface of the test is covered with a minute granulation, scattered among which are
numerous small tubercles.

CRETACEOUS ECHINODERMATA, 87

The apical system is small and compact, and the four large genital plates are distinctly per-
forated. The right anterolateral plate occupies the center of the disk. The five small oculars
are wedged in between the genitals.

The peristome is transversely oblong and situated in a depression.

The periproct is situated high upon the truncated posterior margin and is small and oval,
acuminate below.

Related forms.—It seems not improbable that Spatangus columbianum, described by Lea
in 1840, from the United States of Colombia, may prove to be identical, or at least very closely
related to the Texan form. The indistinct figure shows a different arrangement of the pores
in the anterolateral ambulacra, but it is doubtful whether it can be depended upon for such
details of structure.

Enallaster peruvianus, described by Gabb in 1876, from material obtained from Peru, seems
to be identical.

Among the European Enallasters none apparently are closely related to Hnallaster texanus.

Localities —Very common near Fredericksburg (type), Leon Sprimgs (figured specimen), and
at numerous other localities in Texas, and near Inichtea, N. Mex.

Geologic horizon.—Trinity, Fredericksburg, and Washita groups of the Comanche series,
‘Cretaceous.

Collection.—U. S. National Museum (9857).

ENALLASTER OBLIQUATUS Clark.
Plate XL, figures la-l.

Enallaster obliquatus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Enallaster obliquatus Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 79, 80, Pl. XL, figs. la-1.

Determinative characters—Test oval, cordiform; upper surface convex, flattened and
depressed anteriorly, elevated posteriorly; lower surface flat, with peristomial depression; apex
forward of the center. Ambulacra narrow, unequal. Surface of the plates covered with small
tubercles and intervening microscopic granulation. Apical system compact. Peristome trans-
versely subpentagonal. Periproct situated on truncated posterior margin.

Dimensions.—Length 49 millimeters; width 45 millimeters; height 26.5 millimeters.

Description.—This species has a broad cordiform test, flattened and slanting on the anterior
upper surface, whence the name obliquatus. The anterior groove is deep, wider at its head, and
cuts broadly into the anterior margin. The posterior portion of the test is elevated near the
apex and obliquely truncated toward the margin. The sides are sloping anteriorly, fuller pos-
teriorly. The base is flat with a deep peristomial depression.

The ambulacra are narrow and unequal. The anterolateral pair are slightly depressed
and curved backward in the upper portion. The pores are unequal, those of the anterior zone
‘small and near together, those of the posterior elongated, the outer much more so than the inner
series. There are about 40 pairs of pores in each zone.

The posterolateral paimare short and slightly depressed. The pores are more nearly equal
and about 24 pairs are found in each zone. The single ambulacrum is placed in the anterior
groove and is much wider than the paired ambulacra. The pores of the different plates vary in
size and position. The plates in the lower portions of the areas are large and oblong in form.

The surface of the test is covered with minute tubercles between which is a micrdscopic
granulation. ‘The apical system is small and compact.

The peristome is transversely subpentagonal. The periproct is oval and situated high on
the truncated posterior margin.

Related forms.—E. obliquatus is separated from E. texanus, the only other representative
of this genus from the Cretaceous deposits of the United States, by its broader depressed form,
more sunken anterior sulcus, and lower position of the periproct. These features seem to be
characteristic of nearly all the forms from the Glen Rose beds and perhaps should not be re-
garded as of specific value. Some specimens more or less intermediate in their characters are

§8 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

found, and it may perhaps be wiser to regard the difference as varietal rather than specific. This
species is related to H. mexicanus, described by Cotteau in 1890, from material obtained from
Mexico. :

Localities —Near Austin (type) and Glen Rose and other localities in Texas.

Geologic horizon.—Glen Rose limestone of the Trinity group, Comanche series, Cretaceous.

Collections. —U. S. National Museum (12237); Geological Survey of Texas.

Genus HEMIASTER Desor.
HEMIASTER ELEGANS Shumard.
Plate XLI, figures la-c; Plate XLII, figures la-h; Plate XLII, figures la-t.

Hemiasier elegans Shumard, 1853, Pal. Expl. Red River of Louisiana in 1852, p. 210, Pl. II, figs. 4a-c.

Toxaster elegans Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Toxaster elegans Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177) p. 3.

Macraster tecanus Roemer, 1888, Neues Jahrb., vol. 1, pp. 191-195, Pl. VI, figs. 1-4.

Epiaster elegans Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Epiaster elegans Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Epiaster elegans Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 80-82, Pl. XLI, figs. la-b; Pl. XLII, figs. la-b; Pl. XLIII,
figs. la-e.

Epiaster electus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 152.

Epiaster elegans Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 152.

Epiaster elegans var. nov. prenumtius Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 152.

Epiaster elegans, Hill and Vaughan, 1898, U. S. Geol. Survey Eighteenth Ann. Rept., pt. 2, Pl. LVI, fig. 3.

Epiaster elegans Hill, 1901, U. S. Geol. Survey Twenty-first Ann. Rept., pt. 7, pp. 226, 251, 260, Pl. XXXVI, fig. 4.

Determinative characters.—Test large, oblong, cordiform, flattened both above and below;
sides rounded, with a shallow anterior groove and truncated posterior margin. Ampbulacra
subpetaloidal, depressed; poriferous zones straight, pores with elongated, slitlike openings.
Apical system small. Peristome transversely oval, situated near the anterior margin. Peri-
proct oval, situated on the truncated posterior margin.

Dimensions.—Length 30 to 110 millimeters; width 25 to 100 millimeters; height 15 to 55
millimeters.

Description.—Roemer in 1888 established a new genus and species, Macraster texanus, for a
form that is identical with Hemiaster elegans described by Shumard in 1853. There does not
seem to be a sufficiently wide difference between the characters assigned to Macraster and those
properly belonging to Hemiaster to warrant the acceptance of the former genus for the present
species.

The test is very large and flattened on both the upper and lower surfaces. The sides are
round. The groove on the anterior face is shallow and cuts the margin lightly. The posterior
face is obliquely but not broadly truncated.

The ambulacral areas are nearly equal, depressed, with a distinct furrow on the upper sur-
face. The poriferous zones are long, wide, and straight, and the pores consist of slitlike openings.
The zones are subpetaloidal on the upper surface, reaching quite to the upper margin of the
rounded sides. The unpaired ambulacrum is narrower than the others; the pores are smaller
and more closely approximated.

The surface of both areas is covered with minute tubercles, between which are microscopic
eranules.

The apical system is small, compact, and consists of four large perforated genital plates and
five small oculars.

The peristome is transversely oval and situated near the anterior margin.

The periproct is large, oval, and situated on the truncated face of the posterior margin.

This and the succeeding species are now referred to the genus Hemiaster, as better material
has shown that peripetalous fascioles are present although poorly developed and commonly
destroyed on most specimens.

Related forms.—H. elegans is most nearly related to H. whitei, but is separated from it by its
great size, its excessively long subpetaloidal areas, and the position of its periproct, which is on

CRETACEOUS ECHINODERMATA. 89

an obliquely truncated surface that opens downward instead of being, as in EZ. whitei, on a verti-
cal face that opens upward.

Localities.—Fort Washita (type), Fort Worth (figured specimen), and numerous other locali-
ties in Texas.

Geologic horizon.—Fort Worth limestone of Washita group, Comanche series, Cretaceous.

Collections. National Museum (21887); Johns Hopkins University; Boston Society
of Natural History; Geological Survey of Texas.

HeMIASTER WHITE Clark.
Plate XLIII, figures 2a-c; Plate XLIV, figures la-h; Plate XLV, figures la-d, 2a-f.
Toxaster elegans Conrad, 1857, U. S. and Mex. Boundary Survey Rept., vol. 1, pt. 2, p. 146, Pl. X XI, figs. la-e.!
Epiaster whiter Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.
Epiaster whitet Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Epiaster whitei Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 82, 83, Pl. XLIII, figs. 2a-d; Pl. XLIV, figs. la-g.
Epiaster hemiasterinus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 153.
Epiaster whitei Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 154.
Epiaster hemiasterinus Cragin, 1894, Colorado Coll. Studies, vol. 5, pp. 45, 47.
Epiaster whitei Hill, 1901, U. S. Geol. Survey Twenty-first Ann. Rept., pt. 7, p. 226.

Determinative characters.—Test small, cordiform; upper surface convex, elevated; lower
surface flat; sides inflated; apex forward of the center. Ambulacra moderately broad, petaloi-
dal, pores with elongated openings; anterolateral pair bent slightly backward in upper part.
Aysiall system solieanl Peristome transversely oval. Periproct small, oval, situated high
on posterior border.

Dimensions.—Length 10 to 50 millimeters; width 8 to 45 Sil ates height 16 to 30
millimeters.

Description.—The test is small and cordiform. The upper surface is distinctly elevated, the
apex occupying a point anterior to the center. The lower surface is flat with the exception of the
peristomial depression. ‘The sides are inflated with a well-marked groove at the center of the
anterior face and a prominent truncated surface on the posterior margin.

The ambulacra are moderately broad. The poriferous zones are subpetaloidal in their
upper part, but this feature does not continue to the margin. The pores in the paired ambulacra
are all of about equal size and equally spaced. In the unpaired ambulacrum they are smaller
and nearer together. The anterolateral pair are bent slightly backward in their upper part.
They are distinctly larger than the posterolaterals. The interambulacra are prominent and the
surface of the plates covered with minute tubercles and microscopic granules. The apical system
is small, compact, and consists of four large perforated genital plates and five oculars. The
peristome is transversely subpentagonal and situated near the anterior margin. The periproct
is small, oval, and situated high on the truncated posterior margin.

Related forms.—In many particulars Hemiaster whitei is to be closely associated with H
elegans. It is, however, more elevated, its ambulacral furrows are shorter, and its periproct is
differently Simetted (See p- 88.)

Localities—Duck Creek, near Denison (type), and numerous other localities in Texas.

Geologic horizon.—Fredericksburg group and lower part of Washita group, Comanche series,
Cretaceous.

Collections.—U. S. National Museum (4544, 9732, 31202); Johns Hopkins University.

HemiasTer BExARtI Clark, n. sp.
late XLVI, figures la-e.
Determinative characters.—Test small, upper surface nearly flat, elevated, lower surface
rounded; ‘sides inflated; apex nearly central, posterolateral ambulacra very short, interam-

bulacra prominent. Peristome small, only slightly depressed, near anterior margin. Periproct
small, situated high on truncated surface of posterior margin.

1 Figured under the name Holaster elegans.

90 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions.—Length 22.5 millimeters; width 21.25 millimeters; height 15.5 millimeters.

Description.—This small species has a broad, nearly flat upper surface, rismg toward the
center, which is slightly elevated. The lower surface is rounded, sloping from near the center in
all directions. The sides are inflated.

The ambulacra are unequal, the posterolateral pair being very short. The poriferous zones
are broad and shallow and but little depressed. The anterior ambulacrum is broad and shallow.
The surface is covered with small tubercles. The peripetalous fasciole is distinct.

The peristome is small, only shghtly depressed, and near the anterior margin. The peri-
proct is small and situated high on the truncated surface of the posterior margin.

Locality.—Bexar County, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collection.—U.S. National Museum (8330).

HEMIASTER COMANCHEI Clark, n. sp.
Plate XLVI, figures 2a-d.

Determinative characters.—Test small to medium size, cordiform, high, lower surface flat,
sides inflated, apex forward of the center, peripetalous fasciole broad and clearly marked; ambu-
lacra rather narrow, depressed, petaloidal, the posterolateral considerably shorter than the
anterolateral, apical system nearly central; peristome near forward margin; periproct small,
high on sloping posterior surface, showing clearly from above.

Dimensions.—Length 25 to 60 millimeters; width 22 to 50 millimeters; height 18 to 30
millimeters.

Description.—The test of this species is small to medium sized, cordiform in ambital outline
and high. The upper surface is somewhat inflated, the lower surface nearly flat. The sides are
inflated.. The apex is forward of the center.

The ambulacra are rather narrow and depressed, the poriferous zones petaloidal but narrow,
the posterolateral pair being considerably shorter than the anterolateral. The single anterior
ambulacrum in a broad, moderately depressed sulcus. The mterambulacra are covered with
numerous irregularly scattered granules. The peripetalous fascioles are broad and distinct, with
granules scattered here and there over the surface. The apical system is nearly central on the
upper surface. The peristome is transversely ovate and near the forward margin. The periproct.
is small, high on sloping posterior surface, and showing clearly from above.

Related forms.—H. comanchei is the earliest of the Comanchean hemiasters and possesses
certain generalized features which suggest that it is the ancestral form from which H. whitei,
H. elegans, H. dalli, and H. calvini were derived.

Locality.—Santa Monica Springs, bed of Colorado River, 10 miles west of Austin, Tex.

Geologic horizon.—Glen. Rose limestone of Trinity group, Comanche series, Cretaceous.

Collection. Johns Hopkins University (T 3012).

HEMIASTER DALLI Clark.
Plate XLVII, figures la-f.

Henviaster dalli Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.
Hemiaster dalli Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.
Hemiaster dalli Clark, 1893, U. S. Geol. Survey Bull. 97, p. 89, Pl. XLVIII, figs. 2a-e. :

Determinative characters.—Test cordate, subhexagonal, depressed; upper surface with
sharp ridges between the ambulacral furrows; base flat; sides rapidly declining; anterior margin
deeply grooved. Ambuiacra unequal, very deeply depressed on petaloidal portions; antero-
lateral pair much bent in upper part. Peristome oval, situated on vertically truncated surface
of posterior margin.

Dimensions.—Length 45 millimeters; width 45 millimeters; height 21 millimeters.

CRETACEOUS ECHINODERMATA. 91

Description —This species is much depressed, with distinct marginal angles that give it a
subhexagonal outline. Prominent ridges cross the upper surface between the ambulacral fur-
rows. The anterior sulcus cuts deeply into the test and grooves the anterior margin. The sides
decline rapidly to the flattened base. The low posterior surface has a nearly vertical truncation
of smail area.

The ambulacra are very deeply depresssd on the upper surface, a feature much more pro-
nounced than in any other American species. The anterolateral pair are bent backward in
their upper part, and have long, deep furrows. The posterolateral pair are about one-half the
length of the anterior pair. The single ambulacrum is situated in the broad, deep, anterior
sulcus. The poriferous zones in the paied ambulacra are broad, the pores oval, those of each
pair united by a shallow furrow. In the unpaired ambulacrum the poriferous zones are narrow,
and the pores small and approximated.

The surface is covered with small tubercles with sunken areolas that increase in size toward
the base, where they are large, with distinctly perforated mamelons and crenulated bosses. A
fine microscopic granulation fills the interspaces.

The apical system is sunken, small, and posterior to the center of the upper surface.

The peristome is transversely oval and close to the anterior margin. The periproct is oval
and situated on the truncated surface of the posterior border.

Related forms.—The very deep ambulacral furrows and angular outline readily separate
H. dalli from any other American species. It is not closely allied to any European form.

Locality —Bexar County, Tex.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collection.—U. S. National Museum (19114).

HEMIASTER CALYVINI Clark.

Plate XLVII, figures 2a-i.

Hemiaster calvini Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.
Hemiaster calvini Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 90, 91; Pl. XLIX, figs. 2a-i.

Determinative characters.—Test oval, cordate, inflated; upper surface elevated; lower sur-
face flat; posterior margin obliquely truncated. Ambulacra moderately depressed on the upper
surface. Peristome transversely oval. Periproct oval, high on truncated posterior border.

Dimensions.—Length 21 to 38 millimeters; width 20 to 35 millimeters; height 16 to 33
millimeters.

Description.—This species has an elevated test that is oval, cordate, and broadly truncated
on the posterior margin. The anterior sulcus is shallow and produces but a feeble groove on the
anterior margin. The base is flat.

The ambulacra are narrow. The poriferous zones are broad; the petals moderately
depressed and of good length; the pores in the petaloidal portions of the paired ambulacra
elongated, slitlike, those of the unpaired ambulacrum small and approximated. Beyond the
petals the pores are very small, and occupy the lower outside corner of each plate.

The surface of the plates is covered with small perforated tubercles rather widely scattered
between which a microscopic granulation intervenes. The peripetalous fasciole is indistinct.

The apical disk is small, compact, and nearly central.

The peristome is small, transversely oval, and situated at a distance from the margin. The
periproct is oval and situated high on the truncated surface of the posterior margin.

Related forms.—H. calvini is most closely related to H. whitei, from which, however, it is
distinguished by its more elevated form and its small, narrow, anterior suleus. The apical
system is also more excentric.

Localities —Shoal Creek (type), near Denison, near E! Paso, and other localities in Texas.

Geologic horizon.—Washita group of the Comanche series, Cretaceous.

Collections.—U. S. National Museum (12241); University of Iowa.

92 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

HEMIASTER PARASTATUS (Morton).

Plate XLVIII, figures la—n.

Spatangus sp. Morton, 1830, Am. Jour. Sci., Ist ser., vol. 17, p. 286. :

Spatangus cor-marinum (?) Morton, 1830, Am. Jour. Sci., Ist ser., vol. 18, p. 250, Pl. III, fig. 10.
Spatangus cor-marinum (?) Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, p. 199.
Spatangus parastatus Morton, 1833, Am. Jour. Sci., Ist ser., vol. 23, p. 294. ;

Spatangus parastatus Morton, 1834, Synopsis Organic Remains Cretaceous, p. 77, Pe shiewze
Hemiaster parastatus Agassiz and Desor, 1847, Catalogue raisonné, p. 141.

Hemiaster parastatus D’ Orbigny, 1847, Prodrome, vol. 2, p. 270.

Spatangus parastatus Bronn, 1848, Index palzontologicus, vol. 1, p. 1160.

Hemiaster parastatus D’Orbigny, 1853-1856, Paléontologie frangaise, vol. 6, p. 265, Pl. DCCCXCIYV, fig. 4.
Hemiaster parastatus Desor, 1858, Synopsis des échinides fossiles,‘p. 373.

Holaster parastatus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Hemiaster (?) parastatus Meek, 1864, Smithsonian Misc. Coll., vol. 7, (177), p. 3.

Hemiaster parastatus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, pl. 77.

Hemiaster parastatus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Hemiaster parastatus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 83, 84, Pl. XLV, figs. la—m.

Hemiaster parastatus Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Hemiaster parastatus Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 298-300, Pl. XV.
Hemiaster parastatus Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, No. 1, pp. 9, 10.

Determinative characters —Test cordiform, inflated; upper surface elevated, with deep groove
on anterior surface and sharp ridge posteriorly that is terminated by the flat, nearly vertical,
truncated face of the posterior margin. Ambulacral petals depressed, the anterior pair twice as
long as the posterior. Apical system small, compact. Peristome with distinct, overhanging
lip. Periproct small, situated high on truncated surface.

Dimensions.—Length 37.5 millimeters; width 37.5 millimeters; height 28.12 millimeters.

Description.—This interesting and rather common form has a high, cordiform test, with
deep anterior sulcus and high posterior ridge on the upper surface, the latter terminated by the
high and nearly vertically truncated face of the posterior margin. The sides are rounded and
inflated. The base is flat, with the exception of the peristomial depression.

The ambulacra are very unlike. The poriferous zones are distinctly petaloidal. The petals
of the posterolateral pair are short and broad. Those of the anterolateral pair are bent back-
ward at their center, depressed, and about twice the length of the posterolateral pair. The pores
are slightly elongated. The unpaired ambulacrum is very broad, the poriferous zones far apart,
and the pores small and approximated. 5

The surface is covered with small tubercles, between which are numerous microscopic
granules.

The apical system is small and situated posteriorly to the center of the upper surface. The
four genital plates are distinctly perforated and separated by the five small oculars.

The peristome is transversely arched and bilabiate. The lower lip projects prominently.
The periproct is small and situated high on the truncated surface of the posterior margin. The
peripetalous fasciole is broad and distinct.

Related forms.—H. parastatus is most closely related to H. wngula, from which, however, it is
separated by its deeper and broader anterior sulcus, more posterior position of the apical system
and more inflated sides. It is apparently distinct from all of the many species described from
European deposits.

Localities —Gloucester County (type), Timber Creek, and Vincentown (figured specimen),
N.J.; Pontotoc, Ala. (Slocum).

Geologic horizon.—Vincentown sand of Rancocas group, New Jersey, and Ripley formation,
Alabama; Upper Cretaceous.

Collections —Academy of Natural Sciences of Philadelphia (1487); American Museum of
Natural History, New York; Johns Hopkins University. :

CRETACEOUS ECHINODERMATA. 93

HEMIASTER STELLA (Morton).
Plate XLVIilI, figures 2a-d.

Spatangus stella Morton, 1830, Am. Jour. Sci., Ist ser., vol.18, p. 245, Pl. ITI, fig. 11.

Spatangus stella Morton, 1830, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 6, p. 200.

Spatangus stella Morton, 1834, Synopsis Organic Remains Cretaceous, p. 78, Pl. III, fig. 18.

Hemiaster stella Agassiz and Desor, 1847, Catalogue raisonné, p. 141.

Hemiaster stella Desor, 1858, Synopsis des échinides fossiles, p. 373.

Hemiaster stella Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Hemiaster (?) stella Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Hemiaster wetherbyi De Loriol, 1887, Recueil zool. Suisse, vol. 4, pp. 391-394, Pl. XVII, figs. 5-8.”

Hemiaster incrassatus Olark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Hemiaster stella Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Hemuaster stella Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 84, 85, Pl. XLVI, figs. la-d.

Hemiaster stella Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Hemiaster stella Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 300-301, Pl. XVI,
figs. 1+4.

Determinative characters.—Test small, oval, inflated, rounded before, truncated behind; upper
surface elevated posteriorly, sloping anteriorly; anterior groove short, not reaching the ambitus.
Ambulacra straight, depressed above. Apical system excentric and posterior. Peristome
bilabiate and near the anterior border. Periproct small, high above posterior margin. Fas-
ciole distinct.

Dimensions.—Length 25 millimeters; width 21.9 millimeters; height 15.6 millimeters.

Description.—This form was originally described by Morton in 1830, later, in 1833, it was
considered by the same writer as the young of the species for which the name parastatus was then
proposed. #H. incrassatus is only a large form of H. stella and Hemiaster wetherbyi is also appar-
ently identical with the same species.

The test is small, oval, and cordate, and much elevated on the posterior portion of the upper
surface. The whole test has a rounded, full outline, that is much increased by the absence of
the usually deep anterior groove, which in H. stella does not reach the margin. The posterior
border is nearly vertically truncated.

The ambulacra are depressed in the petaloidal portions which, in the anterolateral pair,
are twice as long as in the posterolateral. The poriferous zones are narrow; the pores have
transverse slitlike openings. The unpaired ambulacrum is situated in the anterior groove.

The surface of the test is covered with innumerable small tubercles between which is a
microscopic granulation. The peripetalous fasciole is very distinct, oval, and passes with a
regular curve about the ends of the petaloidal areas. The surface of the test is covered with
minute tubercles, between which are microscopic granules. The apical system is small and is
situated posteriorly to the center of the upper surface of the test.

The peristome is transversely oval, bilabiate, and placed near the anterior margin. The
periproct is small, oval, and is situated at the upper part of the truncated posterior margin.

Related forms.—The shallow anterior groove which falls short of the margin and the full
elevated test readily distinguish it from other species.

Localities.—Gloucester (type), near Blackwoodstown (figured specimen), and Timber
Creek, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections.—U. S. National Museum (2208); Academy of Natural Sciences of Philadelphia;
Johns Hopkins University.
Hemiaster unGuLa (Morton).

Plate XLVIII, figures 3a-g.

Spatangus sp. Morton, 1830, Am. Jour. Sci., Ist ser., vol. 17, p. 286.

Spatangus ungula Morton, 1833, Am. Jour. Sci., 1st ser., vol. 23, p. 131, Pl. X, fig. 6.
Spatangus ungula Morton, 1834, Synopsis Organic Remains Cretaceous, p. 78, Pl. X, fig. 6,
Micraster ungula Agassiz and Desor, 1847, Catalogue raisonné, p. 141.

Spatangus ungula Bronn, 1848, Index palzeontologicus, vol. 1, p. 1161.

39800°—15——7

94 MESOZOIC AND CENOZOIC ECHINODERMATA CF THE UNITED STATES.

Holaster ungula Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Hemiaster ungula Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.

Hemiaster ungula Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Hemiaster ungula Clark, 1893, U. 8. Geol. Survey Bull. 97, pp. 85, 86, Pl. XLVI, figs. 2a-g.

Hemiaster ungula Johnson, 1905, Acad. Nat. Sci. Philadelphia Proc., vol. 57, p. 7.

Hemiaster ungula Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 301-302, Pl. XVI,
figs. 5-11.

Determinative characters.—Test oval, cordiform, elevated; upper surface inflated, elevated
posteriorly; lower surface flat; sides sloping; anterior suleus narrow and deep. Ambulacra
narrow; poriferous zones straight, depressed, petaloidal. Peripetalous fasciole deeply bent
inward between the anterior and posterior paired ambulacra. Apical system small, compact.
Peristome transversely oval near anterior margin. Periproct oval, supramarginal.

Dimensions.—Length 31.25 millimeters; width 28 millimeters; height 21.9 millimeters.

Description.—This species has an oval, cordate test, that is very much elevated in the
posterior portion. Anteriorly the upper surface slopes rapidly, so that the margin is much
thinned down, losing the full round aspect of the previously described forms. The sharp ridge
on the posterior portion of the test is terminated by a nearly vertical truncation of the posterior
margin. The base is flat, save for the peristomial depression.

The ambulacra are narrow. The poriferous zones are vetaloidal, straight, and deeply
depressed on the upper surface. The unpaired ambulacrum is placed in the anterior sulcus and
but slightly exceeds the other areas in width. The petals of the anterolateral pair are twice
the length of the posterolateral. The pores of the paired ambulacra are elongated and sepa-
rated, those of the smgle ambulacrum small, oval, and approximated.

The surface of the test is covered with small tubercles, between which are numerous minute
granules. The peripetalous fasciole is distinct and bent outward between the anterior and
posterior paired ambulacra.

The apical system is small and situated posterior to the center of the upper surface. The
right anterolateral genital plate is very large and widely separates the posterior pair of oculars.
The posterolateral genitals have large perforations.

The peristome is transversely oval, bilabiate, with a prominently projecting lower lip.
The periproct is large and is situated at the upper part of the truncated face of the posterior
margin.

Related forms.—It is separated from H. parastatus, with which it is found, by the narrower
anterior groove, more central apical system, less inflated sides and sharper posterior keel.

Localities. Chesapeake & Delaware Canal (type), and Timber Creek and Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections.—Academy of Natural Sciences of Philadelphia (1503); American Museum of
Natural History, New York; Johns Hopkins University.

HEMIASTER TEXANUS Roemer.
Plate XLIX, figures la-j.

Hemiaster tecanus Roemer, 1849, Texas, p. 393.

Hemiaster tecanus Roemer, 1852, Die Kreidebildungen von Texas, p. 85, Pl. X, fig. 4.
Hemiaster americanus Gabb, 1853, Naturwiss. Ver. in Halle Jahresb., pp. 372, 373.

Hemiaster tecanus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Hemiaster tecanus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Hemiaster tecanus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.

Hemiaster tecanus Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.

Hemiaster texanus Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 86, 87, Pl. XLVII, figs. 1a-i.
Hemiaster tecanus Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 155.

Hemiaster tecanus Aguilera, 1897, Inst. geol. México Bol. Nos. 4, 5, 6, p. 215.

Hemiaster tecanus Hill and Vaughan, 1898, U. S. Geol. Survey Eighteenth Ann. Rept., pt. 2, Pl. LX, figs. la, 1b.
Hemiaster ? texanus Bosé, 1899, Inst. geol. México Bol. No. 3, p. 11.

Hemiaster texanus Hill, 1902, U. 8. Geol. Survey Twenty-first Ann. Rept., pt. 7, Pl. XLV, fig. 5

CRETACEOUS ECHINODERMATA. 95

Determanative cheracters.—Test oval, cordate, declining anteriorly, elevated slightly posteri-
orly; anterior sulcus broad and deep, producing groove in margin. Ambulacra broadly de-
pressed on upper surface; antero-lateral pair bent backward in upper part; unpaired ambula-
erum very broad. Apical system compact, the four genitals distinctly perforated. Peristome
large, transversely oval, bilabiate. Periproct large, oval, at center of truncated surface of
posterior margin.

Dimensions.—Length 22 to 38 millimeters; width 21 to 36 millimeters; height 15 to 20
millimeters.

Description.—This important species is broadly cordate and slightly depressed on the upper
surface; base flat. Posterior to the apex there is asharp ridge that declines gradually toward the
obliquely truncated margin. Anteriorly the upper surface declines toward the anterior border.

The ambulacra are broad, very unequal, and depressed in the petaloidal portions. The
poriferous zones are broad, the pores of the paired ambulacra elongated, those of the single ambu-
lacrum round and approximated. The petals of the anterolateral pair are bent backward in
their upper part and are nearly twice the width of the posterolateral pair. The single ambula-
crum is very broad, the poriferous zones widely separated.

The surface of the test is covered with small tubercles that are perforated and for the most
part crenulated. A microscopic granulation fills the intertubercular space.

The apical system is small and compact and situated near the center. The four genital
plates are distinctly perforated; the right anterolateral is larger than the others and serves as
the madreporite. The five oculars are wedged between the genitals and are deeply cut by the
upper portions of the ambulacra.

The peristome is large, transversely oval, and bilabiate. The periproct is large, oval, and
situated in the center of the truncated surface of the posterior margin.

Related forms.—Under the name of Hemiaster americanus, Giebel published in 1853 the
description of a new species of Hemiaster which he states can be with difficulty distinguished
from H. texanus. It is considered identical in the present report since the differences seem
hardly to warrant the establishment of a new species. Periaster australis, described by Gabb
from Peru, as far as the figures and description show, must be a Hemiaster, and to all appear-
ances is closely allied if not identical with H. teranus.

Localities. —At waterfall of Guadalupe below New Braunfels (type), Fairview (figured speci-
men), and Austin, Tex.

Geologic horizon.—Austin chalk, Upper Cretaceous.

Collections —U. 8S. National Museum; Johns Hopkins University (T 3013).

HEMIASTER HUMPHREYSANUS Meek and Hayden.

Plate XLIX, figures 2a-f.

Hemiaster (?) humphreysanus Meek and Hayden, 1857, Acad. Nat. Sci. Philadelphia Proc., vol. 9, pp. 147, 148.
Hemiaster (?) humphreysanus Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Hemiaster (?) humphreysanus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (177), p. 3.

Hemiaster humphreysanus Meek, 1876, U. S. Geol. and Geog. Survey Terr. Final Rept., vol. 9, pp. 5, 6, Pl. X, figs. la-g.
Hemiaster humphreysanus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.

Hemiaster humphreysanus Clark, 1893, Johns Hopkins Univ. Circ., vol. 12, No. 103, p. 52.

Hemiaster humphreysanus Clark, U.S. Geol. Survey Bull. 97, p. 88, Pl. XLVIII, figs. la-t.

Determinative characters.—Test oval, cordate; upper surface high, flat, with broad, vertical
truncation on posterior margin, and long anterior groove; base flat; sides rounded. Ambulacra
in deep furrows that reach to the edge of the elevated sides. Apical system large and compact,
posteriorly situated. Peristome small, transversely oval, and bilabiate. Periproct oval, situ-
ated high on posterior margin.

Dimensions.—Length 32.5 millimeters; width 31.5 millimeters; height 20.5 millimeters.

Description.—The absence of distinct fascioles on the type specimens of this species caused
Meek and Hayden to place it doubtfully in the genus Hemiaster, to which beyond doubt it belongs.
The test is full, the sides rounded, and the high upper surface distinctly flattened. The base is

96 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

also flat, with the exception of the peristomial depression. The situation of the apex so far pos-
terior to the center of the upper surface produces a long anterior sulcus, that grooves the anterior
margin. A high, vertically truncated surface terminates the posterior margin.

The ambulacra are broad, very unequal, and deeply depressed on the upper surface. The
petals of the posterolateral pair are very short, those of the anterolateral very long, the latter
quite three times the length of the former. The unpaired ambulacrum occupies the long anterior
suleus. The anterolateral pair are bent backward in the upper part and forward in the lower.
The poriferous zones are broad, the pores distinct and oval. Since much of the surface of the
test has suffered removal the character of the tubercles and granules can not be fully determined.

The apical system, which in the specimen examined kas been largely destroyed, was evi-
dently large, compact, and situated far posterior to the center of the upper surface.

The peristome is small and situated near the anterior margin. The periproct is oval and
situated on the vertically truncated surface of the posterior margin.

Related forms.—H. humphreysanus is a unique form and is not related to, any species of
Hemiaster hitherto described.

Locality —One hundred and fifty miles from the mouth of the Yellowstone River in Mon-
tana (Meek and Hayden).

Geologic horizon.—Pierre shale, of Montana group, Upper Cretaceous.

Collection —U.S. National Museum (331).

HEMIASTER CALIFORNICUS Clark.
Plate L, figures la-d.

Hemiaster californicus Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.
Hemiaster californicus Olark, 1893, Johns Hopkins Uniy. Circ., vol. 12, No. 103, p. 52.
Hemiaster californicus Clark, 1893, U. 8. Geol. Survey Bull. 97, p. 90, Pl. XLIX, figs. la-c.

Determinative characters —Test small, subquadrate, depressed; upper surface flat, with
shallow.anterior sulcus, sloping sides, and low truncated posterior margin; lower surface flat.
Ambulacra depressed, in shallow furrows. Apical system small, posterior to center. Peristome
transversely oval near anterior margin. Periproct situated on the low truncated surface of the
posterior margin.

Dimensions.—Length 28 millimeters; width 27 millimeters; height 11 millimeters.

Description —This form has the details of its structure poorly preserved in the specimens
examined, although it belongs, beyond much doubt, to the genus Hemiaster. The test is small,
much depressed, and subquadrate in ambital outline. It is broader anteriorly, with a feeble
groove in the center of the anterior margin. The posterior portion of the test is but slightly
more elevated than the anterior, and the truncated margin is low and narrow. The base is flat,
with the exception of the peristomial depression.

The ambulacra are but slightly depressed in the petaloidal portions. The poriferous zones
are broad, and the oval pores are united by shallow furrows. The apical system is small and
situated slightly forward of the center. The peristome is transversely oval and situated near
the anterior margin. The periproct is small, oval, and situated on the low, truncated surface of
the posterior border. p

Related forms.—From its shallow ambulacral furrows, Hemiaster californicus may be com-
pared to H. humphreysanus, but is readily separated from it because of its more central apical
system and its depressed form.

Locality —Redding, Shasta County, Cal.

Geologic horizon.—Chico formation, Upper Cretaceous.

Oollection.—U.S. National Museum (31203).

HEMIASTER BEECHERI Clark, n. sp.
Plate L, figures 2a-c.

_Determinative characters—Test large, cordiform, elevated; upper surface inflated, depressed
posteriorly; ambulacra broadly depressed on dorsal surface, anterior ambulacrum in broad
sulcus.

CRETACEOUS ECHINODERMATA. 97

Dimensions.—Length 70 (?) millimeters; width 59 millimeters; height 41 millimeters.

Description.—This large species is represented by a single specimen. ‘The test is cordiform
in ambital outline and elevated. The upper surface is much inflated, sloping rapidly to the sides
and toward the posterior margin, which is much depressed. The ambulacra are deeply de-
pressed, in broad grooves which distinctly affect the ambital outline. The interambulacra form
projecting ridges, the posterior interambulacrum producing a sharp crest. The apical system
is situated in a pronounced apex anteriorly. The peristome is located in a well-marked depres-
sion near the anterior margin.

Locality —Sage Creek, 8. Dak.

Geologic horizon.—Pierre shale of Montana group, Upper Cretaceous.

Collection. Peabody Museum, Yale University (1863).

HeMIASTER LACUNOSUS Slocum.
Plate L, figures 3a-d; Plate LI, figures la-i.
Hemiaster lacunosus Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, No. 1, pp. 10, 11, Pl. II, figs. 1-7.

Determinative characters.—Test small, indistinctly cordate, upper surface slightly convex,
elevated posteriorly; sides inflated; lower surface nearly flat. Ambulacra narrow, poriferous
zones not deeply depressed the posterolateral pair being quite short. Peripetalous fasciole
distinct. Peristome large, near anterior margin. Periproct high on posterior truncated surface.

Dimensions.—Length 17.8 to 23.4 millimeters; width 16.3 to 23.6 millimeters; height 11.8
to 17 millimeters.

Description.—Slocum says:

Test small, indistinctly cordate, ventral surface moderately convex, dorsal surface convex, strongly elevated in the
posterior interambulacral area and gradually sloping with an indistinct anterior sulcus; anterior and lateral borders in-
flated, posterior margin truncated. Ambulacral areas petaloid, with straight petals situated in depressions cf the surface,
the anterolateral pair nearly twice as long as the posterolateral pair; poriferous zones of the paired petals wide, pores
transversely elongate and situated far apart. Anterior petal longer but narrower than the others and situated in a
deep depression which grades into an indistinct anterior sulcus; poriferous zones of this petal narrow and far apart;
pores small, round, and separated by atubercle. Interambulacral areas broad and composed of large plates. Surface
of the test covered with a multitude of small tubercles with sunken areoles that increase in size toward the peristome.
The tubercles have perforated mamelons and crenulated bosses, the interspaces being filled with microscopic granula-
tions. Peripetalous fasciole wide and distinct, moderately bent inward between the petaloid areas except the two
posterior ones. Apical disk sunken, small, and situated somewhat posterior to the center of the dorsal surface, the four
genital plates distinctly perforated and separated by five small radial plates. Right anterior genital plate large, convex
and forming the madreporite. Peristome transversely arched, bilabiate, with prominent labrum. Periproct about
the size of the peristome, elongated vertically and situated near the top of the posterior truncation.

Related forms.—H. lacunosus resembles H. parastatus in general form and proportions, but is distinguished from that
species by its smaller size and by the sunken areoles of the tubercles. Moreover, the posterior interambulacral area is
rounded, while in H. parastatus it isin the form ofaridge. H. lacwnosus is similar to H. stella in size, but differs from
itin the shape of the fasciole, the sunken areoles and the form of the anterior margin. It resembles H. dalli in having
sunken areoles, but in general form these two species are quite dissimilar. The specific name adopted refers to the
sunken areoles by which the species is distinguished.

Locality.—Pontotoe and Houston, Miss.

Geologic horizon.—Ripley formation, Upper Cretaceous.

Collections.—U. S. National Museum (31204); Field Museum (P 10342).

HeEMIAsTER KUMMELT Clark.
Plate LI, figures la-c.
Hemiaster kiimmeli Clark, 1907,in Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp.
303-304, Pl. XVII, figs. 1-3.

Determinative characters.—Test cordate, slightly elevated. Upper surface nearly flat, with
weakly depressed petaloidal areas; the lower surface flat. Peristome with distinct overhanging
lip.

Dimensions.—Length 30 to 55 millimeters; width 30 to 40 millimeters; height about 20
millimeters.

98 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Description.—This species is represented by numerous flattened casts, none of which show
clearly the original form of the test, although it is apparently somewhat flatter than the other
New Jersey Cretaceous Hemiasters. The test is relatively large. It is but slightly elevated
with a somewhat flattened upper surface.

The ambulacra are pronounced, with weakly depressed petaloidal areas. The unpaired,
posterior interambulacrum is nearly flat with a low truncated posterior surface. The petals of
the posterolateral pair are relatively long and narrow and less than twice the length of the
anterolateral pair. The unpaired ambulacrum is not deeply depressed and does not form a
pronounced sulcus on the anterior margin. The apical system is small but not as strongly
excentric as in some of the other Cretaceous species. The peristome has a distinct overhanging
lip. The peripetalous fascioles can not be seen.

Related forms.—This species is related to both H. parastatus and H. welleri. From the
former it is separated by its shallower and narrower ambulacral petals and less elevated form;
from the latter by its longer and narrower posterolateral ambulacral petals and flatter form.

Locality.—Lorillard clay pits near Keyport, N. J.

Geologic horizon.—Woodbury clay of Matawan group, Upper Cretaceous.

Collections.—Geological Survey of New Jersey; Johns Hopkins University.

HEMIASTER WELLERI Clark.

Plate LIT, figures 2a-c.

Hemiaster welleri Clark, 1907, in Weller, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp- 302-
303, Pl. XVII, figs. 4-6.

Determinative characters.—Test cordiform, inflated; upper surface only slightly elevated
posteriorly; lower surface flat; sides rounded. Ambulacra depressed. Apical system small.
Peristome with distinct overhanging lip. Periproct small, high on posterior truncated surface.

Dimensions.—Length 27 millimeters; width 24 millimeters; height 17 millimeters.

Description.—This species has afforded few specimens, and those for the most part casts, but
it is evidently distinct from the other forms described. The test is moderately high, clearly cor-
diform, and with depressed ambulacra. The anterior sulcus is broad and clearly defined but does
not deeply indent the anterior ambitus. The posterior ridge is not greatly accentuated and ter-
minates in a well-defined, truncated posterior surface. The sides are rounded. The lower sur-
face is slightly inflated.

The ambulacra are moderately depressed in their petaloidal portions, the posterolateral pair
being considerably shorter than the anterolateral, although the difference is less marked in this
species than in the other New Jersey Cretaceous Hemiasters. The anterior ambulacrum is in a
broad shallow groove that largely disappears before the ambitus is reached.

The syoneni system is small and imperfectly shown on the casts from which its characters can
be alone obtained.

The peristome is of moderate size with distinct overhanging lip. The periproct is small and
situated high on the truncated posterior surface.

Related forms.—Hemiaster welleri is related to H. parastatus from which, however, it is sepa-
rated by its less deeply depressed ambulacral furrows and less elevated upper surface. It also
shows points of resemblance to H. kummeli from which, however, it is separated by its lower
posterolateral ambulacral petals and less elevated mostenton ridge on the upper surface.

Localities—Railroad cut 1 mile south of Lower Jamesburg (type); 3 miles east of James-
burg; Reeves clay pit; Lenola; bluff east of Atlantic Highlands, N. J.

Geologic horizon.—Merchantville clay of Matawan group and Navesink marl of Monmouth
group, Upper Cretaceous.

Collections —Geological Survey of New Jersey; Johns Hopkins University.

CRETACEOUS ECHINODERMATA. 99

Genus LINTHIA Merian.
LIntTHrIa TUMIDULA Clark.
Plate LIII, figures la-i.
Linthia tumidula Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.
Linthia tumidula Clark, 1893, Johns Hopkins Univ. Cire., vol. 12, No. 103, p. 52.
Lintha tumidula Clark, 1893, U.S. Geol. Survey Bull. 97, pp. 91, 92, Pl. I, figs. la-i.
Tinthia tumidula Weller, 1907, Cretaceous paleontology of New Jersey: Geol. Survey New Jersey, pp. 304-305, Pl.
XVIII, figs. 1-9.

Determinative characters.—Test oval, cordiform, elevated; apex central; posterior border
obliquely truncated, anterior portion grooved by narrow sulcus; sides sloping. Ambulacral
furrows long, straight, depressed; poriferous zones broad, pores oval. Apical system small,
nearly central. Periproct on truncated posterior border. Peripetalous and lateral fascioles
distinct.

Dimensions.—Length 53 millimeters; width 50 millimeters; height 28 millimeters.

Description.—This large form has an elevated test, with flattened, sloping sides, oval outline,
and a narrow, moderately depressed, anterior sulcus that grooves the anterior margin. The base
is flat, except for the peristomial depression.

The ambulacra are narrow and furrow for a long distance the upper surface of the test to a
moderate depth. The poriferous zones are broad and straight. The pores are large and oval,
and those of each pair connected by a shallow furrow. The anterolateral petals reach far down
the sloping sides and are about one and one-half times as long as the posterolateral pair.

The surface of the test is covered with minute, perforated tubercles that are much longer on
the base than on the upper surface. A microscopic granulation fills the space between the tuber-
cles. Both the peripetalous and lateral fascioles can be readily traced. The apical system is
small, nearly central, and slightly depressed. The peristome is transversely oval and situated
near the anterior margin. The periproct is small, oval, and situated but a short distance above
the posterior margin.

Localities —Timber Creek and Vincentown, N. J.

Geologic horizon.—Vincentown sand of Rancocas group, Upper Cretaceous.

Collections.—American Museum of Natural History, New York; Boston Society of Natural
History; Johns Hopkins University.

LINTHIA VARIABILIS Slocum.
Plate LIV, figures la-l.
Linthia variabilis Slocum, 1909, Field Mus. Nat. Hist. Pub. 134, Geol. ser., vol. 4, No. 1, pp. 12-14, Pl. III, figs. 1-11.

Determinative characters —Test cordate, upper surface elevated, under surface nearly flat,
sides inflated, apex nearly central. Ambulacra in relatively deep depressions. Peristome near
anterior margin. Periproct near top of posterior truncation.

Dimensions.—Length 17. 1 to 31.6 millimeters; width 16.6 to 29.1 millimeters; height 10.1
to 19.6 millimeters.

Description.—Slocum says:

Test distinctly cordate, truncated posteriorly, ventral surface depressed convex, dorsal surface elevated, forming
a sharp ridge in the posterior interambulacral area. Sides inflated and sloping to the lateral and anterior margins;
posterior truncation slightly concave and the angle between the truncation and the base line varying from 77° to 90°.
Ambulacral areas straight, petaloid, situated in comparatively deep depressions of the dorsal surface. Anterolateral
pair about one and one-half times the length of the posterolateral pair, poriferous zones of these four petals wide, pores
elongated and slitlike. Each pair of pores connected by a shallow groove and the pore near the border of the
petal the larger. Unpaired anterior ambulacral area situated in a deep depression the continuance of which forms a
sulcus in the anterior margin. Poriferous zones of this area narrow and situated far apart. Pores round and each pair
separated by a tubercle. Interambulacral areas broad and composed of large plates. Surface of the test covered with

100 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

minute perforated tubercles having crenulated bosses. The tubercles increase in size as they approach the peristome.
Interspaces filled with small tubercles and microscopic granulations. Both peripetalous and lateral fascioles are clearly
defined, peripetalous fasciole decidedly bent inward between the anterolateral and posterolateral petals and somewhat
less so between the other petals. Apical system situated in the center or somewhat anterior to the center of the dorsal
surface, small, depressed, having the four genital plates perforated and separated by five small radials. Peristome
transversely elliptical, situated near the anterior margin. Labrum prominent. Periproct somewhat elongated ver-
tically and situated near the top of the posterior truncation.

Related forms.—L. tumidula, the only other species of this genus hitherto described from
the American Cretaceous, is so unlike L. variabilis that detailed comparison is unnecessary.

Localities. —Oinainiile Run, Pontotoc, and Tippah County, Miss.

Geologic horizon.—Ripley Rommnetiom, Upper Cretaceous.

Collection.—Field Museum, Chicago (P 10457).

PART II—THE CENOZOIC ECHINODERMATA.

By Witt1am Buxtock Crark and Mayvitte W. TwircHeEtt.

INTRODUCTION.
GEOLOGIC AND GEOGRAPHIC RANGE.

The Cenczoic Echinodermata discussed in the succeeding pages, although largely confined to
the Eocene, are by no means absent from later deposits. The Eocene forms are very abundant
and embrace some of the most diagnostic fossils of that age, but they are less common than
in the Cretaceous. They are found at several Eocene horizons on the Atlantic and Pacific coasts,
but are more numerous and characteristic in the Eocene of the South Atlantic and Gulf Coastal
Plain, where they occur in large numbers. Nearly all that have been collected belong to the
group Echinoidea, although representatives of Crinoidea, Asteroidea, and Holothuroidea have
beenfound. Among the echinoid genera recognized are Cidaris, Ceelopleurus, Echinocyamus,
Fibularia, Scutella, Mortonella, Periarchus, Clypeaster, Echinanthus, Cassidulus, Breynella,
Echinolampas, Hemipatagus, Brissopsis, Linthia, Schizaster, Eupatagus, Macropneustes, and
Sarsella.

The Oligocene strata of the South Atlantic and Gulf areas have in few places been satisfac-
torily delimited from the Eocene, so that the age of some of the echinoid material can not be
determined with certainty. Among the known Oligocene genera of the South Atlantic and Gulf
areas are Cidaris, Echinocyamus, Laganum, Amblypygus, Oligopygus, Cassidulus, Echinolampas,
Agassizia, Schizaster, and Eupatagus. The great majority of the forms come from Florida.
The Oligocene deposits of California have also furnished specimens of Cidaris.

The Miocene deposits of both the Atlantic and Pacific coasts have afforded a considerable
number of echinoderms, chiefly echinoids. The Atlantic coast Miocene contains Ophioderma (2),
.Cidaris, Ceelopleurus, Psammechinus, Scutella, Mellita, Encope, Cassidulus, Agassizia, Brissus,
Plagionotus, and Echinocardium. The Pacific coast Miocene has furnished Asterias, Amphiura,
Cidaris, Scutella, Dendraster, Astrodapsis, Scutaster, Clypeaster, and Linthia.

The Pliocene deposits contain very few echinoderms. On the South Atlantic coast from
the Carolinas southward a few forms have been recognized, among them Strongylocentrotus,
Encope, and Diplothecanthus. On the Pacific coast Dendraster, Astrodapsis, and Schizaster (?)

arefound. The Miocene and Pliocene echinoids of the Pacific coast have been found to be of mote.
than ordinary value in the determination of geologic horizons. This is due to their limited
geologic range and to the fact that, where present at all, they are usually abundant and well
preserved.

The Pleistocene deposits likewise have furnished very few echinoderms, and those for the
most part of species living in the adjacent seas. Among those recognized from the Atlantic
border have been Asterias, Strongylocentrotus, Mellita, Moira, and Toxopneustes. On the
Pacific coast, on the other hand, several species of Strongylocentrotus and Dendraster are
found.
The absence of species identical with those of other continents and particularly of Europe
renders it impossible to attempt detailed correlation of American and foreign horizons. Genera
represented in the main divisions of the Cenozoic in America are with scarcely an exception
similar to those typical of the same divisions elsewhere.

The accompanying tables show the stratigraphic position of the more important American
Cenozoic formations, the geologic distribution of the Cenozoic Echinodermata of the United
States, and the distribution of eastern Gulf Eocene and Oligocene Echinodermata.

101

102 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Stratigraphic position of the more important American Cenozoic formations.

[Vertical parallel lines indicate formations which occur in separate areas and whose exact equivalence is not established.]

Series. FN Eastern Gulf area. South Atlantic border. Middle Atlantic border.
| Pamlico
Talbot
: 3 | Chowan
8 _ (Satilla cso é
Pleistocene | San Pedro 22| we { Wicomico
[o) he =
6° (Okefenokee S| sunderland
|| Coharie
}
Pliocene? Lafayette ? Lafayette? . Lafayette
Pliocene SEAS Caloosahatchee || Nashua Waccamaw » Waccamaw
San Pablo Duplin © {Yorktown
Pascagoula : ad
Santa Margarita § |St. Marys
Miocene Be
Monterey § |Choptank || Cohansey
Jacksonville || Choctawhatchee Edisto || Marks Head 5S
Vaqueros Calvert {/ Kirkwood
[Shoal River Alum Bluff
4:4 3 |Alum Bluff; Oak Grove feet
Soir |Chipola aso
Oligocene San Lorenzo eli) <4a¢
Chattahoochee || Tampa Chattahoochee
fet Pao
8 cme (eran Vicksburg
n8a
areas
a ec ackson Jackson || Cooper Castle Hayne
Tejon & 4
ospor'
Ciaibome| Liston Claiborne (Coe ee Trent
ata 5
Eocene atchetigbee 4 Nemene
. Bashi : . ae Sk Ye
Wilcox [ie Onan Wilcox || Williamsburg g HH, =e
Nanafalia ay q
Martinez Naheola 3
Midway 4Sucarnochee Midway || Black Mingo Shark River
Clayton
Geologic distribution of the Cenozoic Echinodermata of the United States.
Oligo- . . Pleisto-
Eocene. Gane, Miocene. | Pliocene. Aaa.
Crinoidea:
Dicyclica—
Flexibilia—
Pinnata—
Antedonize—
Zenometray(?)iconoideus (Emmons) spss eaeeee eee eee eee eee eee | Pt CoE Soe EH aSEcose HaeeadotaG Seo ascocs
Stelleroidea: >
astaroldea
ptozonia—
ies Asteriidze—
Asterias (?) sp -..-.--
Asterias remondii Gabb.
Asterias stellionura Poiret.
iAsterias incl Mullerse seo eee eee eee eee ee eee eee
Ophiuroidea—
Zy gophiurze— | |
Ophiodermatida— . 1
Ophioderm~a! (2) ‘spsatsece soe be eee ee ee ee es ean PS RRR USS a a aa SET ea eas
Amphiuridze— |
AT phiuralsanctaccucis eso] des sees eeees eee es pe eee a eee ase Eee alee eee lace sae, eh ral beesacae ss eabacee a
Echinoidea: |
Regularia endobranchiata— |
Cidaroidea— |
Cidaridae—
Cidarissmitchellithimimonssee ee teet eee eee eee eee eee eee eee eee eee aeeee Xx
Cidanis|carolinensis/Hmmionsse ae seen eee ame een een nen mp x
Cidaris pratt, Clarks eae ee nee eee ee enon ase x
(@Uubrajninabyam Awl pe soon soeedcossenosse ose secaescasaseLosees x
CidanisnmosTeus|dey Greg Oia Nene eee see ae eee eR nan a x
CidarisimodestusidelGrezonloss eee ese eee eee ees x
Cidaris ordinatus de Gregorio. - . Fey ee et eet RE Ee x
Cidaris pecans de Gregorio. -- OS NS REE REP IDET Nea x
Cidaris)blandis|de)iGreronlospeeee eee eee ee een eee ee eee eee >
Cidaris alabamensis Morton. x
Cidaris sp.......- x
Cidaris'mortoni| Conrad (ieee Mees RR ee EE ee Meee ane
GCidaris|smiith iy Clarke ee Re ae ee RS eer Sere er ar a eI
Cidaris/georgianal Clarkes 05 ioe ae Se ae em ae ie a ti a ar OS Seay a
Cidaris brannerieArnol dey ee yee a ere sane ee ee ee Re eee ee een
Cidarisithouarsi((?)avalencienneseeseeseeneeeeee sere ee eee tere eee eens Besenaosad

INTRODUCTION,

Geologic distribution of the Cenozoic Echinodermata of the United States—Continued.

103

Miocene.

Echinoidea—Continued.
Regularia ectobranchiata—
Diademoidea—
Arbacina—
Arbaciidee—
Ceelopleurus infulatus (Morton)
Ccelopleurus aldrichi Clark __._-
Ccelopleurus improcerus (Conrad). -
Ccelopleurus sloani Clark.......

Meh inocidanistsp oy c Cra d yews nse ee oe een: merece ae nu pve tials hud

Diademina—
Cyphosomatidzee—
Orthechinus

Echinina—
Triplechinide—
Echinus exerceus de Gregorio
Echinus (?) s

Psammechinus philanthrop}
Psammechinus exoletus McCrady -- -
Toxopneustes virgiegatus (Lamarck)
Strongylocentrotida—
Strongylocentrotus drébachiensis (Miiller)

Irregularia—

Gnathostomata—

Clypeastrina—
Fibulariidze—
Echinocyamus parvus Emmons..........-
Echinocyamus huxleyanus Meyer...
Echinocyamus texanus Twitchell. .
Echinocyamus vaughani Twitchell
Sismondia (?) plana Conrad.-...-

Sismondia (?) arnoldi Twitchell... .
Sismondia (?) coalingaensis Twitchell -
Fibularia meridionalis (Meyer)...........--
Laganidze—
Laganum (?) crustuloides (Morton)
Laganum eldridgei Twitcheli
Laganum archerensis Twitchell...
Laganum johnsoni Twitchell_._-__-
Laganum floridanum Twitchell
Laganum dalli Twitchell........-
Scutellidee—
Scutella mississippiensis Twitchell. - --.

Scutella tuomeyi Twitchell. ........-

Scutella (?) conradi (Cotteau).....-
Scutella andersoni Twitchell. --...-
Scutella fairbanksi Pack....-.....-
Scutella (?) merriami (Anderson) -.
* Scutella norrisi Pack

Scutella gabbi (Rémond) Merriam...
Mortonella quinquefaria (Say)
Periarchus altus Conrad
Periarchus lyelli Conrad...........--
Periarchus protuberans Twitchell... -..
Periarchus pileus-sinensis (Ravanel)- - .
Dendraster perrini (Wieser)
Dendraster arnoldi Twitchell-....-----
Dendraster gibbsii (Rémond)
Dendraster oregonensis (Clark)
Dendraster coalingaensis Twitchell --.-
Dendraster interlineatus Coteep son) Set
Dendraster excentricus (Eschscholtz)- - - -
Astrodapsis antiselli Conrad...........--
Astrodapsis arnoldi Twitchell
Astrodapsis whitneyi Rémond..-.
Astrodapsis tumidus Rémond .
Astrodapsis jacalitosensis Arnol
Astrodapsis fernandoensis Pack
Mellita caroliniana Ravenel.

ppxetiosus| Clarice hus ie Seam scecnees hoc ces ener a ee

Strongylocentrotus franciscanus A. Agassiz.
Strongylocentrotus purpuratus (Stimpson). .

Atelostomata—

Mellita pentapora Gmelin. .
Scutaster andersoni Pack...........-...-------

Encope macrophora Ravenel..........-------------------------------+--- :

Clypeastrid2—
Clypeaster rogersi (Morton)

Clypeaster bowersi Weaver...........---------
Clypeaster (?) brewerianus (Rémond)
Diplothecanthus dalli Twitchell.............-..-..-
piplothecan thus rosaceus (Lamarck)
Echinanthus georgiensis Twitchell

Asternata—

Nucleolitide—
Amblypygus merrilli Twitchell
Oligopygus wetherbyi De Loriol.-
Oligopygus haldermani (Conrad).
Oligopyeus flonidanuseRwitchellgesasce ose one cena ae ees ence eee eeneeee |

Cassidulidae— -
Cassidulus californicus F. M Anderson...........--.--------------------
Cassidulus (Rhynchopygus) (?) holmesi Twitchell 3
Cassidulus (Rhynchopygus) lyelli (Conrad)
Cassidulus (Rhynchopygus) raveneli Twitchell
Cassidulus (Rhynchopygus) patelliformis Bouvé.......----.-.--
Cassidnhis (Rhynchopygus) depressus Twitchell_.......-...--.------.---

MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Geologic distribution of the Cenozoic Echinodermata of the United States—Continued.

Oligo-

Eocene.
¢ cene.

Miocene.

Echinoidea—Continued.
Trregularia—Continued.

Atelostomata—Continued.
Asternata—Continued.
Cassidulidee—Continued.
Cassidulus (Pygorhynchus) conradi Conrad..............-.-..-----------
Cassidulus (Pygorhynchus) carolinensis Twitchell. - 3
Cassidulus (Pygorhynchus) georgiensis Twitchell. .
Cassidulus (Pygorhynchus) gouldii Bouvé
Cassidulus (Pygorhynchus) alabamensis Twitchell. -

Cassidulus bassleri Twitchell. ...............-----.
Cassidulus berryi Twitchell. -
Breynella gregoryi Twitchell..............------
Echinolampas Bead Emmons.........--

Ichi; Twitchell ee ese Da eae

Echinolampas a!
Sternata—
Spatangidae—

Efemipatapusiarcii tus! Clarkes esse ee eee ee eee eee ee ee eee

Hemipatagus subrostratus Clark.
Schizaster lecontei Merriam. .
Schizaster armiger Clark.

Schizaster sp.....-----

Schizaster floridanus Clark.
Schizaster americana Clark...
Schizaster (?) stalderi Weaver. -
Schizaster atropos (Lamarck). -
Linthia wilmingtonensis Clark-
Linthia alabamensis Clark... ..
Linthia (?) californica Weaver.
Eupatagus carolinensis Clark. -
Eupatagus floridanus Clark...
Brissopsis rimulatus Ravenel. - .-
Macropneustes carolinensis Clark.
piscropneustes mortoni (Conrad).

Sarsella gregoryi Clark

Spatangus (?) pachecoensis Pack.
Agassizia conradi (Bouvé)......-
Agassizia porifera (Ravenel)......-
Echinocardium orthonotum Conrad...
Echinocardium depressum Clark... .
Echinocardium gothicus (Ravenel)
Brissus spatiosus (Ravenel)....
Metalia ravenelianus McCrady .
Metalia holmesi McCrady.......---

Pleisto-
cene.

Pliocene.

Holothurioidea:
Paractinopoda—
Synaptidae—
(Qbineh Py Sos caaosdascnsous da scososonboduhasdonaodasSsecoucadsosessedeseos||ssdodasucc Sa Py eaadasseec| Sacesccouallacoasossoc
SKA OIRVC an SUG A caaAanueecotoae GoudecobLpadseSscnasncadasacdsoosdaosecon|loscsossode Oh UMlaeweGadapel boradeedec |oonacacte
Stratigraphic distribution of eastern Gul f Eocene and Oligocene Echinodermata. »
Eocene. Oligocene.
pee 1 Clai- ¥ Vicks- | Apalachi-
Midway. | Wilcox. once Jackson. burg. aie
CidarisiblandisidexGregorio- sen ses sec ee oe see ee eens ene eee aera

Cidaris ordinatus de Gregorio.......--
Cidaris perdubius de Gregorio... ..-.--
Cidaris moereus de Gregorio. ---....--
Cidaris modestus de Gregorio. ..-.--
Cidaris alabamensis Morton.....-.-.-
Cidaris|sp oe saneet eas seca ae eee
Cidaris mortoni Conrad-
Cidaris smithi Clark. -..
Cidaris georgiana Clark............---
Ccelopleurus aldrichi Clark...........
Orthechinus pretiosus Clark. ......-
Gagaria americana Clark...........-
Echinus exerceus de Gregorio.....-.
chinws|speeeeees hee {ieee ene
Echinocyamus huxleyanus Meyer. -
Echinocyamus texanus Twitchell.
Echinocyamus vaughani Twitchel
Fibularia meridionalis (Meyer). - -
Laganum eldridgei Twitchell
Laganum archerensis Twitchell... ....
Laganum johnsoni Twitchell. ....
Laganum floridanum Tvitchell.
Laganum dalli Twitchell. ...-...:_.
Scutella mississippiensis Twitchell...
Mortonella Goran (Saya) sean
Periarchus lyelli Conrad

Echinanthus georgiensis Twitchell... .
Amblypygus merrilli Twitchell... .-
Oligopygus wetherbyi De Loriol . --

Oligopygus haldermani (Conrad)....-..-.-

XXKXKX

INTRODUCTION. 105

Stratigraphic distribution of eastern Gulf Eocene and Oligocene Echinodermata—Continued.

Eocene. Oligocene.

Vicks- | Apalachi-
burg. cola.

Clai-

Midway.| Wilcox. borne. | J2¢kson.

OligopyeusHfloridanusmiwatcnellSesewep rea ac) aan a caesarean esse cena) eee pen
Cassidulus (Rhynchopygus) lyelli (Conrad).....-...-...---------- come

Cassidulus (Rhynchopygus) patelliformis Bouvé-.
Cassidulus (Rhynchopygus) depressus Twitchell
Cassidulus (Pygorhynchus) conradi Conrad...
Cassidulus (Pygorhynchus) georgiensis Twit
Cassidulus (Pygorhynchus) gouldii Bouvé -.....-.-
Cassidulus (Pygorhynchus) alabamensis Twitchell... nee
Echmolampasjaldrichi-twitchellee- sens. - seen enone ceeeeenae
Hemipatagus argutus Clark...........--.- NESRORERECSEaEOES
Agassizia conradi (Bouyé)... ise ee ee res
Schizaster armiger Clark... ae nee ees
Schizaster floridanus Clark. ae BERS eae Oe
Schizaster americana Clark. - Se eee Cees
Linthia alabamensis Clark...
Macropneustes mortoni (Conr: sf ae: Brees E
pEupatac Us Homa anus) Ola niksesemen meee oes ents meeioee sai weston ae Me nenien senna nus Semana

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Pliocene fossils of South Carolina, 1855.

Mrcuetrin, H., Echinides vivants et fossiles des Antilles et du Golfe du Mexique: Soc. géol. France Bull., 2d ser., vol.
12, pp: 759-760, 1855.

INTRODUCTION. 107

1856.

Bruunes, E., On the Tertiary rocks of Canada with some account of their fossils: Canadian Naturalist and Geologist, Ist
ser., vol. 1, pp. 321-346, 1856. ae

Buaxe, W. P., Geology of the vicinity of San Francisco: Pacific Railroad Repts., vol. 5, pp. 153, 154, 1856.

Conrap, T. A., Descriptions of three new genera; twenty-three new species middle Tertiary fossils from California and
one from Texas: Acad. Nat. Sci. Philadelphia Proc., vol. 8, pp. 312-316, 1856.

Mrcuetry, H., Moules en platre de deux échinides des couches supra-crétacées de la Jamaique: Soc. géol. France Bull.
2d ser., vol. 13, p. 222, 1856. 7 D

1857.
Conran, T. A., U.S. Pacific railroad explorations and surveys, 32d parallel and California, vol. 7, p. 196, Pls. IX, X
1857. :
Sruvpson, Wirram, Crustacea and Echinodermata of Pacific shores of North America: Boston Soc. Nat. Hist. Jour.
vol. 6, 1857.

Tuomey, M., and Homes, F. 8., Pliocene fossils of South Carolina, 152 pp., 28 pls., 1857. (Part on Echincdermata
published in 1855.)

1858.

Desor, E., Synopsis des échinides fossiles, 644-490 pp., 43 pls., Genéve, Paris, and Wiesbaden, 1858.

Emmons, E., Agriculture of the eastern counties together with descriptions of the fossils of the marl beds: North Caro-
lina Geol. Survey Rept., pp. 1-314, Raleigh, 1858.

Hormes, F. S., Post-Pliocene fossils of South Carolina, Charleston, 1860. (Part on Echinodermata published in 1858.)

Micueuin, M. H., Revue des espéces connés et nouvelles du genre Mellita: Rev. et mag. zoologie, 2d ser., vol. 10, pp.
358-364, Pls. VIII, IX, 1858.

1859.

Gass, W. M., Catalogue of the invertebrate fossils of the Cretaceous formation of the United States: Acad. Nat. Sci.
Philadelphia Pamph., 19 pp., 1859.
McCrapy, J., Remarks on the Eocene formation near Alligator, Fla.: Elliott Soc. Nat. Hist. of Charleston, S. C., Proc.,
vol. 1, pp. 282, 283, 1859.
1861.

Micnettn, M. H., Monographie des Clypeastres fossiles: Soc. géol. France Mém., 2d ser., vol. 7, pp. 103-147, Pls. IX—
XXXVI, 1861.
1862.

Dosarpin, F., and Hur, H., Histoire naturelle des zoophytes échinodermes, 627 pp., atlas with 10 pls., Paris, 1862.
1863.

ReEmonp, Avauste, Description of four new species of Echinodermata from the Tertiaries of Contra Costa County: Cali-
fornia Acad. Nat. Sci. Proc., vol. 3, pp. 52-59, 1863.

Description of two species of Scutella: California Acad. Nat. Sci., vol. 3, pp. 13-15, 1863.

Lirxen, C. F., Bidrag til kundskab om Echiniderne: Vidensk. medd., Kjobenhavn, 1863.

1864.

Meek, F. B., Check list of invertebrate fossils of North America, Miocene: Smithsonian Misc. Coll., vol. 7 (183), pp.
1-32, 1864.
1865.

Conrap, T. A., Catalogue of the Eocene * * * Echinodermata * * * of the United States: Acad. Nat. Sci.
—~ Philadelphia Proc., pp. 73-75, 1865.
Descriptions of new species of Echinidw: Acad. Nat. Sci. Philadelphia Proc., vol. 17, p. 75, 1865.
Observations on American fossils with descriptions of two new species: Acad. Nat. Sci. Philadelphia Proc., vol.
17, p. 184, 1865.
Dawson, J. W., Post-Pliocene deposits at Riviere du Loup and Tadoussac: Canadian Naturalist, 2d ser., vol. 2, pp.
81-88, 1865. ;

1866.

Conran, T. A., Check list of the invertebrate fossils of North America; Eocene and Oligocene: Smithsonian Misc.
Coll., vol. 7 (200), pp. 1-41, 1866.

Guppy, J. L., On Tertiary echinoderms from the West Indies: Geol. Soc. London Quart. Jour., vol. 22, pp. 297-301, Pl.
XIX, figs. 4-8, 1866. :

Packarp, A. S., jr., On the glacial phenomena of Labrador and Maine: Boston Soc. Nat. Hist. Mem., vol. 1, pt. 2, pp.
210-262, 1866.

108 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

1868.

Duncan, P. M., On the anatomy of the test of Amphidetus (Echinocardium) virginianus Forbes: Geol. Soc. London
Quart. Jour., vol. 25, p. 16, 1868.
1869.

Gass, W. M., Cretaceous and Tertiary fossils: Geol. Survey California, Paleontology, vol. 2, 1869.
Lause, G. C., The Echinoida of the upper Tertiaries of Austria and Hungary: K.-k. geol. Reichsanstalt Abh., Wien,
1869.
1872-1874,

Acassiz, A., Revision of the Echini: Mus. Comp. Zoology Illustrated Catalogue No. 7,770 pp., 87 pls., 7 maps, 1872-74.

1872-1875.
QueEnsteEDT, F. A., Petrefactenkunde Deutschlands, vol. 3, Echiniden, 1872-1875.

1875.

Correau, G., Echinides tertiaires des fles St. Barthélemy et Anguilla: Kongl. svensk. Vet.-Akad. Handl., vol. 18,
No. 6, pp. 1-47, Pl. VIII, 1875.

Patstey, C. H., On the post-Pliocene formation near Bathurst, New Brunswick: Canadian Naturalist, 2d ser., vol.
7, pp. 268-270, 1875.

Verritt, A. E., On the post-Pliocene fossils of Sankoty Head, Nantucket Island, Mass.: Am. Jour. Sci., 3d ser., vol.
10, pp. 364-375, 1875.

1876.
Correau, G., Echinides tertiaires des fles Saint-Barthélemy et Anguilla: Soc. géol. France Bull., 3d ser., vol. 5, 1876.

1876-1880.
ZirtEL, K. A. von, Handbuch der Palaeontologie, vol. 1, pt. 1, 1876-1880.

1878.

Hitearp, £. W., and Hopkins, F., Report of specimens from borings between the Mississippi River and Lake Borgne,
La.: Rept. Comm. Engineers, Sup., 1878.
1880.

Agassiz, A., Report on Echini [results of dredging by the Blake, No. 24, pt. 1]:Mus. Comp. Zoology Bull., vol. 8, No. 2,
1880.
1881.

Acassiz, A., Report on the Echinoidea; Report on the scientific results of the exploring voyage of H. M. S. Chal-
lenger, Zoology, vol. 3, pt. 9, 321 pp., 1881.
Corrrau, G., Description des échinides fossiles de l’ile de Cuba: Soc. géol. Belgique Ann., vol. 9, Mém., pp. 3-49,
4 pls., 1881.
1883.

Pomet, A., Classification méthodique et généra des échinides vivants et fossiles, 1883.
Aaassiz, A., Report on the Echini [Results of dredging by the Blake, No. 24, pt. 1]: Mus. Comp. Pies Mem., vol.

10, 94 pp., 32 pls., 1883.
1884.

Heiiprin, ANGELO, Contributions to the Tertiary geology of the United States, Philadelphia, 1884.
Tertiary geology of eastern and southern United States: Acad. Nat. Sci. Philadelphia Jour., vol. 9, pp. 115-154,
1884.

1885.
Quensrept, F. A., Handbuch der Petrefactenkunde, 1885.
1885-1894.

CorrEau, G., [Hchinides éocénes de la France]: Paléontologie frang¢aise, Ist ser., Animaux invertébrés, Terrains
tertiaires, éocéne, Echinides; vol. 1, 1885-1889, 672 pp., 200 pls.;. vol. 2, 1889-1894, 788 pp., 183 pls., Paris.

1886.
Avpricu, T. H., Tertiary fossils of Alabama and Mississippi: Alabama Geol. Survey Bull. 1, pp. 15-60, Pls. I-VI,
1886.

Meyer, Orro, Contributions to the Eocene paleontology of Alabama and Mississippi: Alabama Geol. Survey Bull. 1,
pp. 63-85, Pls. I-III, 1886.

INTRODUCTION, 109

1887.

DE Loriot, P., Notes pour servir 4 l’étude des échinodermes: Recueil zool. Suisse, vol. 4, pp. 365-407, Pls. XV-XVIII,
1887.
Meyer, Orro, Beitrag zur Kenntnis der Fauna des Alttertiirs von Mississippi und Alabama; Nat. Gesell. Bericht.,
22 pp., 2 pls., Frankfurt, 1887.
Suir, E. A., and Jonson, L. C., Tertiary and Cretaceous strata of the Tuscaloosa, Tombigbee, and Alabama rivers:
U.S. Geol. Survey Bull. 43, pp. 1-189, 1887.
1888.

Coorsr, J. G., Catalogue of California fossils: California State Mineralogist Seventh Rept., pp. 223-308; Tertiary
Radiata, pp. 270-271, 1888.
1890.

CuarK, W.B., On the Tertiary deposits of the Cape Fear River region: Geol. Soc. America Bull., vol. 1, pp. 537-540,
1890.

DE GrecorIO, ANTONIO, Monographie de la faune éocénique de l’Alabama: Annales géologie et paléontologie, vol. 2,
pts. 7 and 8, 316 pp. and 46 pls., Palerme, 1890.

DE Lortot, P., Notes pour servir 4 l’étude des échinodermes: Soc. phys. et hist. nat. Geneva Mém., 1890.

i 1891.

_Ciark, W. B., A revision of the Cretaceous Echinoidea of North America: Johns Hopkins Univ. Circ., vol. 10, No. 87,
pp. 75-77, 1891.

Duncan, P. M., Revision of genera and great groups of the Echinoidea: Linn. Soc., Zoology, vol. 23, pp. 1-311, 1891.

Grecory, J. W., The relations of the American and European echinoid faunas: Geol. Soc. America Bull., vol. 3, pp.
101-108, 1891.

A revision of the British fossil Cainozoic Echinoidea: Geologists’ Assoc. Proc., London, vol. 12, Nos. 1, 2, pp.
16-20, 2 pls., 1891.

KeEenneEDY, Wm1IAM, Section from Terrell to Sabine Pass: Texas Geol. Survey Third Ann. Rept., pp. 43-124, 1891.

1892.

Dat, W. H., Correlation papers—Neocene: U.S. Geol. Survey Bull. 84, 349 pp., 3 pls., 1892.
Harris, G. D., The Tertiary geology of southern Arkansas: Arkansas Geol. Survey Ann. Rept., vol. 2, 187 pp., 7 pls.,
1892. ;
1893.
Boyzz, B., A catalogue and bibliography of North American Mesozoic invertebrata: U. 8. Geol. Survey Bull. 102,
315 pp., 1893.
Crark, W. B., The Mesozoic Echinodermata of the United States: U.S. Geol. Survey Bull. 97, 207 pp., 50 pls., 1893.

1894.
Cooper, J. G., Catalogue of California fossils: California Min. Bur. Bull. 4, p. 32, 1894.
1895.

CunnincHaM, K. M., Microscopic fossils in Tertiary marl strata: Am. Micr. Jour., vol. 16, pp. 193-196, 1 pl., 1895.
Dana, J. D., Manual of geology, 4th ed., 898 pp., 1491 figs., 1895.
Kennepy, Wiiu1am, Eocene Tertiary of Texas east of Brazos River: Acad. Nat. Sci. Philadelphia Proc., pp. 118-115,
1895.
1896.

Crarx, W. B., The Eocene deposits of the Middle Atlantic slope: U. 8. Geol. Survey Pull. 141, 167 pp., 40 pls., 1896.
1897.

Ecozcuse y Cia.,J., and Corrzav, G., Descripcién de los equinoides fésiles de la isla de Cuba: Com. de la mapa geol.
Espafia Bol., vol. 22, 99 pp., 29 pls., 1897.
1898.
Merriam, J. C., Distribution of Neocene sea-urchins of middle California: Univ. California Dept. Geology Bull.,

vol. 2, pp. 109-118, 1898.
1899.

Dawson, J. W., Note on anechinoderm * * * in the Pleistocene (Leda clay) collected by Dr. Ami at Besserers,
Ottawa River: Ottawa Naturalist, vol. 13, pp. 201-202, 1899.
Merriam, J. C., The Tertiary sea-urchins of middle California: California Acad. Sci. Proc., 3d ser., Geology, vol. 1,
No. 5, pp. 161-170, Pls. XXI, XXII, 1899.
Scuitrer, CLemeEns, Ueber einige von Goldiuss beschriebene Spatangiden, Part 2: Deutsche geol. Gesell. Zeitschr.,
yol. 51, pp. 101-124, 1899.
39800°—15——8

110 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

f 1901.

CrarK, W. B. and Marri, G. C., Systematic paleontology, Eocene; Mollusca, Brachiopoda, and Echinodermata:
Maryland Geol. Survey, Eocene, pp. 93-331, Pls. X-LXIV, 1901.

1902"

Arnop, D. and A., Marine Pliocene and Pleistocene stratigraphy of the coast of southern California: Jour. Geology,
vol. 10, pp. 117-188, Pls. I-V, 1902.
Crark, H. L., The aantmadlescns an the Woods Hole region: U.S. Fish Comm, Bull. for 1902.
OrtTMAN, A. E., Reports of the Princeton University expeditions to Patagonia, Tertiary invertebrates, vol. 4, pt. 2,
pp. 45-332, Pls. XI-XXXIX, 1902.
1903.

Arnoup, Rapn, The paleontology and stratigraphy of the marine Pliocene and Pleistocene of San Pedro, Cal.: Califor-
nia Acad. Sci. Mem., vol. 3, 1903.

1904.

CrarK, W. B., Systematic paleontology, Miocene Echinodermata: Maryland Geol. Survey, Miocene, pp. 430-433,
Pls. CXIX, CXX, 1904. '

1905. :

AnpErson, F. M., A stratigraphic study in the Mount Diablo range of California: California Acad. Sci. Proc., 3d ser.,
Geology, vol. 2, No. 2, pp. 156-206, with plates, 1905.

ScuuHERT, ©., Catalog of type specimens of fossil invertebrates in the National Museum: U.S. Nat. Mus. Bull. 53, pt. 1,
704 pp., 1905.

Sears, J. H., The physical geography, geology, mineralogy, and paleontology of Essex County, Mass., 418 pp., 209 text
figs., Salem, 1905.

1906.

- Cxark, W. B., and others, Characteristic fossils of Maryland formations: Maryland Geol. Survey Sixth Rept., pt. 1, pp.
252-259, Pls. XVI-XXIII, 1906.
1907.

Arnotp, Rate, New and characteristic species of fossil mollusks from the oil-bearing Tertiary formations of southern
California: U. S. Nat. Mus. Proc., vol. 32, pp. 525-546, Pls. XX XVIII-LI, 1907.

New and characteristic species of fossil mollusks from the oil-bearing Tertiary formations of Santa Barbara
County, Cal.: Smithsonian Misc. Coll., vol. 1, pt. 4, pp. 419-447, Pls. L-LVII, 1907. :

Arnoxp, RatpH, and AnpERsoN, Rosert, Geology and oil resources of the Santa Maria oil district, Santa Barbara
County, Cal.: U. 8. Geol. Survey Bull. 322, 161 pp., Pls. XII-XXVI, 1907.

Expres, G. H., and ArNotp, Ratpu, The Santa Clara Valley, Puente Hills, and Los Angeles oil districts, southern
California: U. 8. Geol. Survey Bull. 309, 220 pp., Pls. XX V—XLI, 1907.

1908.

Arnoup, Raupu, Fossils from Santa Cruz Mountains, Cal.: U. 8. Nat. Mus. Proc., vol. 34, pp. 345-390, Pls. XXXI-
XXXVII, 1908.

New brittle star from Miocene of California: U. S. Nat. Mus. Proc., vol. 34, pp. 403-406, Pl. XL, 1908.

Weaver, ©. E., New echinoids from the Tertiary of California: Univ. Caliioaatn Dept. Geoloxy Bull, vol. 5, No. 17,
pp. 271-274, Pls. XXI, XXII, 1908.

1909.

Arnop, Ratpn, Paleontology of the Coalinga district, Fresno and Kings counties, Cal.; U. 8. Geol. Survey Bull. 396,
101 pp., 30 pls.

Branner, J. C., Newsom, J. F.,and Arnotp, R., U. 8. Geol. Survey Geol. Atlas, Santa Cruz folio (No. 163), 11 pp.,
2 pls., 1909.

Dau, W. H., Contributions to the Tertiary paleontology of the Pacific coast—I, The Miocene of Astoria and Coos Bay,
Oregon: U.S. Geol. Survey Prof. Paper 59, 278 pp., 23 pls., 1909.

Lampert, J., Echinodermes: Rev. crit. paléozoologie, vol. 13, 1909, p. 122.

Pack, R. W., Notes on echinoids from the Tertiary of California: Univ. California Dept. Geology Bull., vol. 5, No. 18,
pp. 275-283, pls. 23, 24,1909.

Weaver, G. E., Stratigraphy and paleontology of the San Pablo formation in middle California: Univ. California Dept.
Geology Pub., vol. 5, No. 16, pp. 248-269, 1909.

INTRODUCTION, ati
1910.

ARNOLD, Rate, and ANDERSON, Rosert, Geology and oil resources of the Coalinga district, Cal.: U. 8. Geol. Survey
Bull. 398, pp. 1-354, Pls. XXIJI-LII, 1910.

Cuark, W. B., and Twircnett, M. W., Geological distribution of Mesozoic and Cenozoic Echinodermata of the United
States: Geol. Soc. America Bull., vol. 20, pp. 686-688, 1908.

Grasau, A. W., and Samer, H. W., North American index fossils, invertebrates, vol. 2, 909 pp., 726 figs., 1910.

Lambert, J., Echinodermes: Rev. crit. paléozoologie, vol. 14, No. 1, pp. 42-55, 1910.

1911.

Lamsert, J., Echinodermes: Rev. crit. paléozoologie, vol. 15, 1911, p. 64.

SreraNinI, G., Sugli echini terziari dell’ America del Nord: Soc. geol. italiana Boll., vol. 30, pp. 677-714, Pl. XXII,
Rome, 1911.

Osservazioni sulla distribuzione geografica, sulla origini e sulla filogenesi degli Scutellide: Soc. geol. italiana

Boll., vol. 30, pp. 739-754, 1911.

Note echinologiche: Revista italiana di paleontologia, vol. 17, pt. 4, pp. 1-16, Pl. V, 1911.

Nore.—A number of contributions have appeared during the progress of this report through the press, the results
of which can not be fully incorporated in the following pages, although footnotes concerning some of them have been
inserted. Among the more important of these publications are :

Pack, R. W., Notes on Scutella norrisi and Scutaster andersoni: California Univ. Dept. Geology Bull., vol. 7, No. 13,
pp. 299-304, Pl. XV, 1913. Pack furnishes additional information of value regarding the species mentioned.

Kew, W. 8. W., Tertiary echinoids of the Carrizo Creek region in the Colorado Desert: California Univ. Dept. Geol-
ogy Bull., vol. 8, No. 5, pp. 39-60, Pls. I-V, 1914. Kew describes the following forms: Encope tenuis n. sp.,

Clypeaster deserti n. sp., C’. carrizoensis n. sp., C. bowersi Weaver, Hipponoé californica n. sp., and Cidaris sp. ~

EOCENE ECHINODERMATA.

Class CRINOIDEA.
Subclass DICYCLICA.

Order FLEXIBILIA.

Suborder PINNATA.

i Family ANTEDONID&.

Genus ZENOMETRA A. H. Clark.
ZENOMETRA (?) coNoIDEUS (Hmmons).

Microcrinus conoideus Emmons, 1858, Agriculture Eastern Counties: North Carolina Geol. Survey Rept., p. 311, figs. 246,

247.

Microcrinus conoideus Conrad, 1866, Check list, Eocene and Oligocene, p. 31.
Description.—The descriptions and figures of this form by Emmons are very inadequate.
Springer, who kindly examined them for the author, says:

Emmons’s figures represent the centro-dorsal of a comatulid, broken away from the radials, preserving the “rosette”
filled with matrix, and the “ basal rays.’”’ The latter indicate noncontiguous basals—a character which removes it from
Atelocrinus. The regular arrangement of cirrus sockets in columns, combined with the large central cavity of the cen-
trodorsal, places it in the family Antedonide, as restricted by Mr. A. H. Clark, and it might belong to a form like his
genus Zenometra, recent species of which occur in the Atlantic and Caribbean from the Carolinas to St. Lucia. Without
the superior parts of the calyx it is impossible to make closer comparison, and it must remain among the imperfectly
known.

No specimens have been secured in recent collecting and no material representing this spe-
cies has been found in any museum.

Locality.—Craven County, N. C. (Emmons).

Geologic horizon.—Trent marl, middle Kocene.

Collection.—Unknown.

Class STELLEROIDEA.
Subclass ASTEROIDEA.
Order: CRYPTOZONIA.
Family ASTERIID.
Genus ASTERIAS Linné.
ASTERIAS (%) sp.

Asterias Morton, 1834, Synopsis Organic Remains Cretaceous, p. 74.

Description.—Morton says: ‘‘I have seen but a few obscure fragments of this genus, from
the calcareous strata of South Carolina.’”’ It is quite impossible without authentic specimens to
determine whether the material in Morton’s hands belongs to this genus or not.

Locality.—South Carolina.

Geologic horizon.—Kocene.

Collection —Unknown.

112

EOCENE ECHINODERMATA., 113

: Class ECHINOIDEA.

Subclass REGULARIA ENDOBRANCHIATA.
Order CIDAROIDEA.
Family CIDARID®.
Genus CIDARIS Leske.
CmpARIS MITCHELLI Emmons.

Plate LV, figures la-c.

Cidaris mitchelli Emmons, 1858, Agriculture Eastern Counties: Rept. North Carolina Geol. Surv ey, p. 305, fig. 237.
Cidaris mitchelli Conrad, 1866, Check list, Eocene and Oligocene, p. 3.

Cidaris mitchelli Heilprin, 1884, Contrib. Tertiary geology, p. 17.

Cidaris mitchelli Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 693.

Determinative characters—Test large, thick, and of moderate height. Ambulacra rather
broad, somewhat undulating with four to six rows of granules between the poriferous ayenues.
Interambulacra wide with 9 to 10 plates in each row, each plate bearing a single large circular
tubercle the arecla of which is surrounded by a row of small tubercles. Miliary space covered
with numerous thickly radiated granules.

Dimensions.—Diameter 53 millimeters; height 32 millimeters.

Description.—The species is represented by a single specimen, the type described by
Emmons, which in many particulars is in an excellent state of preservation. The test is large,
thick, and circular in outline. It is of medium height.

The ambulacra are rather broad and canner undulating, with four rows of granules
between the poriferous avenues toward the apical system and peristome, but with six rows on the
ambitus. The pores are oral and connected by deep furrows. \

The interambulacra are wide and bear two rows of large circular tubercles, the areolas of
which closely approach each other and are covered by a row of small tubercles. The tubercles
are round, depressed, and have much elevated and deeply perforated mamelons.

Related forms.—The species is most closely related to C. carolinensis but is somewhat lower,
the granules on its miliary space are smaller and differently distributed and its tubercles approach
each other more closely. Its areolas have a surrounding row of small tubercles which are absent
in @. carolinensis.

Locality.—Craven County (2), N. C. (Emmons).

Geologic horizon.—Trent marl, middle Eocene.

Collection.—Williams College.

CIDARIS CAROLINENSIS Emmons.
Plate LV, figures 2a-c.

Cidaris carolinensis Emmons, 1858, Agriculture Eastern Counties: North Carolina Geol. Survey Rept., pp. 305-306,

fig. 238.

Giiemetemolireenas Conrad, 1866, Check list, Eocene and Oligocene, p. 31.
Cidaris carolinensis Heilprin, 1884, Contrib. Tertiary geology, p. 17.
Cidaris carolinensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.

Determinative characters —Test large, thick, and rather tall, Ambulacra rather broad,
somewhat undulating, with four rows of granules between the poriferous avenues. Interambu-
lacra wide, each with two rows of large circular tubercles, 10 to 11 in each row. Miliary space
covered with numerous thickly set granules.

Dimensions.—Diameter 60 millimeters; height 35 millimeters.

Description.—The type specimen of Emmons is the only representative of this species that
has been available for study. Although somewhat crushed the portions preserved are in an
excellent state of preservation. The test is of rather large size, thick, and somewhat taller than

in most species of Cidaris.

114 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacra are rather wide and somewhat undulating, with four rows of granules between
the poriferous avenues on the upper and lower surfaces, which become increased to six at the
ambitus. The pores are oval in shape.

The interambulacra are wide, each with two rows of large circular tubercles that however
leave a wide miliary space on each plate that is thickly set with granules of very uniform size
throughout. The tubercles are round and deeply depressed. The boss is smooth and the mame-
lons deeply perforated.

Related forms.—This species 1s closely related to C. mitchelli but is evidently taller and has
larger granules somewhat differently dispersed. Its tubercles are more widely separated than
those of C. mitchell, and its areolas lack the surrounding row of small tubercles.

Locality — Craven County (2), N. C. (Emmons).

Geologic horizon.—Trent marl, middle Eocene.

Collection.— Williams College.

CrpaRis PRATTI Clark, n. sp.
Plate LV, figure 3.

Determinative characters —Test small, thin, rather high, circular. Ambulacra narrow
undulating, two rows of granules between the poriferous avenues; pores nearly round. Inter-
ambulacra wide, each with two rows of tubercles; each tubercle round, depressed, with crenu-
lated boss and perforated mamelon and with areolas surrounded by row of small tubercles.

Dimensions.—Diameter 18 (?) millimeters; height 15 (?) millimeters.

Description.—The only specimens available for study consist of fragments of tests, chiefly
of detached plates. The test is small and thin, rather high, and apparently circular in outline.

The ambulacra are narrow and undulatg. The pores are nearly round. Two rows of
small granules occur between the poriferous avenues.

The interambulacra are wide, each with two rows of tubercles which largely occupy the area
of the plates. The miliary space is very small and covered with granules. Each tubercle has a
depressed areola surrounded by a row of small tubercles. The boss is crenulated and the mame-
lon perforated.

Related forms.—The species is unique and differs widely from the other Tertiary species.
It is more closely related to C. mitchelli than to C. carolinensis.

Locality —Wilmington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collection —U. S. National Museum (164663).

CimpAaRIS MERRIAMI Arnold.

Plate LV, figure 4.

Cidaris merriami Arnold, 1908, U.S. Nat. Mus. Proc., vol. 34, p. 359, Pl. XXXII, fig. 8.
Cidaris merriami Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 696.

Determanative characters.—Test wanting. Spinesubcircular in cross section, tapering slightly;
surface with 13 or 14 prominent ribs separated by narrow grooves; nodes well defined.
Dimensions.—Longest fragment; length 20 millimeters; maximum diameter °4.5 milli-

meters.
Description.—Arnold, in his description of this species, says:

The test of this species is unknown, but the abundance and well marked characteristics of the fragments of the
spines has been deemed of enough importance to justify a specific name. Seven specimens have been obtained at the
type locality, each showing the characters described above.

Spines subcircular in cross section, as much as 4 millimeters in diameter and probably over 40 millimeters in
length, tapering very slightly; surface sculptured by 13 or 14 prominent, narrow, nodose, ridgelike, longitudinal ribs
separated by narrow, deeply incised grooves; the nodes are well defined, especially in the younger stages of growth, and
are subelliptical in cross section, their longer axis being parallel with the axis of the spine.

EOCENE ECHINODERMATA, 115

H. L. Clark, who examined the specimens for Arnold, says that they
Allappear to belong to one species, except possibly one fragment. That piece might possibly have come from quite

a different species. Iam very glad to see this material of merriami, for it satisfies me that the species must have been
allied to, not identical with, Tretocidaris perplexa Clark (Cidaridze, 1907, p. 205, Pl. VI, figs. 1-2; Pl. VII, figs. 14) the
only other living littoral cidarid known from north of Panama (other, I mean, than thouwarsii). So your material
shows that the ancestors of both thouarsii and perplexa lived in the Tertiary in California.

Locality Santa Cruz quadrangle, San Mateo County, locality No. 25, ridge between head-
waters of San Lorenzo River and Pescadero Creek, Cal.

Geologic horizon.—Eocene, possible equivalent of Martinez formation.

Collection —U. S. National Museum (165, 438).

Ciparts M@REUS De Gregorio.

Cidaris mereus De Gregorio, 1890, Mon. faune éocénique Alabama, p. 252, Pl. XLIII, figs. 22-23
Cidaris mereus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Deseription.—No specimens of this species were available for study. The type form described
by de Gregorio evidently came with other materials from the Claiborne in Alabama. The author
describes tne species as follows: ‘‘Aculeus subcylindraceus, obloneus, tuberculis erectis notatis
confertis majoribus et minoribus irregulariter dispositis ornatus.”’

Locality — Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

Ciparis Mopestus De Gregorio.

Cidaris modestus De Gregorio, 1890, Mon. faune éocénique Alabama, p. 253, Pl. XLITI, fig. 26.
Cidaris modestus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No specimens of this species were available for study. The type form de-
scribed by De Gregorio evidently came with other materials from the Claiborne in Alabama.
The author describes the species as follows: ‘‘Aculeus augustus, conoideo-cylindraceus, costulis
longitudinalibus ornatus; costis crenulatis, granulo-squamosis; granulis subimbricatis.”’

Locality.—Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

Ciparis orpinaTUS De Gregorio.

Cidaris ordinatus De Gregorio, 1890, Mon. faune éocénique Alabama, p. 352, Pl. XLIV, fig. 1.
Cidaris ordinatus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No specimens of the species were available for study. The type form described
by De Gregorio evidently came with other materials from the Claiborne group near Claiborne,
Ala. The author describes the species as follows: ‘‘Aculeus subcylindraceus; tuberculis erectis,
raris, subsequalibus, quincuncim atque spiraliter regulariter dispositis.”

Locality Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

116 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

CipaRis PERDUBIUS De Gregorio.

Cidaris perdubius De Gregorio, 1890, Mon. faune éocénique Alabama, p. 253, Pl. XLIV, fig. 2.
Cidaris perdubius Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No specimens of this species were available for study. The type form
described by De Gregorio evidently came with other materials from the Claiborne in Alabama.
The author describes the species as follows: ‘‘Aculeus cylindraceus potius augustus, tenu tuber-
culatus; tuberculis densis, parvis, in series longitudinales recte dispositis.”

Locality.—Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

Crparis BLANDIS De Gregorio.

Cidaris blandis De Gregorio, 1890, Mon. faune éocénique Alabama, p. 253, Pl. XLIV, fig. 4. .
Cidaris blandis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No specimens of this species were available for study. The type form
described by De Gregorio evidently came with other materials from the Claiborne group near
Claiborne, Ala. The author describes the species as follows: ‘‘Aculeus augusta, conoideo-
cylindraceus, costulis longitudinalibus ornatus; costis crenulatis, granulo-squamosis; granulis
subimbricatis.”’

Locality.—Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

CIDARIS ALABAMENSIS Morton.

Cidaris alabamensis Morton, 1846, Acad. Nat. Sci. Philadelphia Proc., vol. 3, p. 51.
(?) Cidaris sp. Aldrich, 1886, Alabama Geol. Survey Bull. 1, p. 43.
Cidaris alabamensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No material has been obtained that can be regarded as belonging to this
species, which Morton very inadequately describes and which he does not figure. Morton in his
description says that this species is ‘‘Compressed, pentagonal, the angles rounded so as to form
a 10-sided figure. Ten rows of tubercles, with 9 or 10 in each row. Ambulacra arranged in
five pairs, with delicate, slightly oblique fissures separated by a double elevated line. Surface
between the tubercles and ambulacra finely granulated.” Morton states that the specimen
described was found in the ‘‘Kocene strata of Washington County, Ala.,” but if it was derived
from the St. Stephens limestone, as seems probable, it may be Oligocene, for the upper beds are
of that age.

Locality —Washington County, Ala. (Morton).

Geologic horizon.—St. Stephens (?) limestone, Eocene (?).

Collection.—Unknown.

CipaRiIs sp.

Cidaris sp. De Gregorio, 1890, Mon. faune éocénique Alabama, p. 252.

Deseription.—The material representing this species is referred to by De Gregorio in these
words: ‘‘Auctor nullam descriptionem hujus specei dat.” No figure is given.

Locality —Near Claiborne, Ala.

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

EOCENE ECHINODERMATA,. 17

Subclass REGULARIA ECTOBRANCHIATA.

Order DIADEMOIDEA.
Suborder ARBACINA.
Family ARBACIID®.
Genus CELOPLEURUS Agassiz.
C@LOPLEURUS INFULATUS (Morton).
Plate LVI, figures la-i.
Echinus infulatus Morton, 1833, Am. Jour. Sci., 1st ser., vol. 24, p. 131, Pl. X, fig. 7.
Echinus infulatus Morton, 1834, Synopsis Organic Remains, p. 75, Pl. X, fig. 7.
Echinus infulatus Morton, 1842, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 8, p. 217.
Echinus infulatus Bronn, 1848, Index palzeontologicus, vol. 1, p. 450; vol. 2, p. 187.
Echino-cidaris infulatus Ravenel, 1850, Am. Assoc. Adv. Sci. Proc., vol. 3, p. 160.
(2?) Arbacia (?) sp. Bouvé, 1851, Boston Soc. Nat. Hist. Proc., vol. 4, p. 3.
Ceelopleurus infulatus Desor, 1858, Synopsis des échinides fossiles, p. 98.
Echinus infulatus Gabb, 1859, Cat. Invertebrate Fossils Cretaceous, p. 19.
Celopleurus depressus Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., vol. 23, p. 74.
Celopleurus infulatus Conrad, 1866, Check list, Eocene and Oligocene, p. 22.
Celopleurus depressus Conrad, 1866, Check list, Eocene and Oligocene, p. 22.
Celopleurus (Echinus) inflatus A. Agassiz, 1874, Revision of the Echini, p. 751.
Echinus infulatus ? Aldrich, 1886, Alabama Geol. Survey Bull. 1, p. 43.
Celopleurus infulatus Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.
Echinus infulatus Boyle, 1893, U. 8. Geol. Survey Bull. 102, p. 118.
Celopleurus infulatus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.
Celopleurus depressus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.

Determinative characters.—Test moderate, depressed. Ambulacra narrow, projecting on
upper surface, with two rows of tubercles extending from the peristome to the apical system,
plates compound except near apex; poriferous avenues narrow; pore pairs uniserial, in arcs.
Interambulacra broad, each with four rows of primary tubercles extending from the peristome
to slightly above the ambitus beyond which the inner rows disappear. Apical system large,
the genital plates in contact. Peristome with small branchial incisions. Periproct large
subpentagonal.

Dimensions.—Diameter 19.5 millimeters; height 10 millimeters.

Description.—This very characteristic species is represented by a single specimen from the
Santee marl member of the McBean formation of South Carolina. The test is of moderate
size, depressed and subpentagonal in outline.

The ambulacra are narrow and project above the general level of the test. Each am-
bulacrum has two rows of primary tubercles that extend from the peristome nearly to the
apex. The tubercles are imperforate and noncrenulate. The plates are compound except
near the apex and consist of one primary and two demiplates. The poriferous avenues are
narrow, and the pore pairs which are uniserial are in arcs.

The interambulacra are broad, each area being covered with four rows of primary tubercles
which extend from the peristome to a little above the ambitus, beyond which the two central
rows disappear, and the outside rows gradually decline in size to very small tubercles or eyen
into granules. The large bare median area produces a broad depression on the upper surface.

The apical system is large, the genital plates coming into contact and separating the small
oculars.

The peristome is large with small branchial incisions. The periproct is large and subpen-
tagonai in outline.

Locality South Carolina (Morton).

Geologic horizon.—Santee marl member of McBean formation, of Claiborne group, middle
Eocene.

Collection.

Academy of Natural Sciences of Philadelphia (1076).

118 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Suborder DIADEMINA.
Family CYPHOSOMATID®.
Genus ORTHECHINUS Gauthier.
ORTHECHINUS PRETIOSUS Clark, n. sp.
Plate LVI, figures 2 a-b.

Determinative characters.—Test small, depressed, circular. Ambulacra wide, with two rows
of low primary tubercles, crenulate and imperforate; poriferous avenues straight, pore pairs
uniserial, with three pairs to each plate. Interambulacra with two rows of primary tubercles
similar to those of ambulacra and with additional smaller tubercles and granules. Apical
system large. Periproct large.

Dimensions.—Diameter 20 millimeters; height 8 millimeters.

Description.—A single crushed specimen of this species has been found. The test is small
depressed, and circular in ambital outlme. The ambulacra are wide with two rows of crenulate
and imperforate small primary tubercles, which are somewhat indistinct on account of their
relatively small, low mamelons and small areolas. Smaller tubercles and granules are also
found. The poriferous avenues are straight, the pore pairs uniserial with three pairs to each
. compound plate.

The interambulacra have two rows of primary tubercles similar to the ambulacra together
with smaller tubercles. The miliary space is covered with irregularly dispersed granules.

The apical system is large, pentagonal in outline, and with large genital plates. The
periproct is large.

Locality—Dead Level, Choctaw County, Ala.

Geologic horizon.—St. Stephens limestone (lower portion), upper Eocene.

Collection.—U. S. National Museum (146455).

Suborder HCHININA.
Family TRIPLECHINID®.
Genus ECHINUS Linné.

Ecuinus pxercEus De Gregorio.

? Echinus sp. Aldrich, 1886, Alabama Geol. Survey Bull. 1, p. 49.
Echinus exerceus De Gregorio, 1890, Alabama Mon. faune €océnique, p. 252, Pl. XLIV, fig. 3.
Echinus exerceus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Description.—No material representing this species was available for study. De Gregorio
gives the following description: ‘‘Aculeus exilis, oblongus, sub lente minutissime eleganter
punctulatus reticulatusque, inferne ad basim turgidus.”

Locality.—Near Claiborne, Ala. (De Gregorio).

Geologic horizon.—Claiborne group, middle Eocene.

Collection.—De Gregorio.

Ecuinus (?) sp.

Plate LVI, figure 3.

Diadematoid spines, Clark and Martin, 1901, Maryland Geol. Survey, Eocene, p. 232, Pl. LXT, fig. 2.

Description.—Several small, thin echinoid spines, the generic relations of which can not be
with certainty determined, have been found in the Eocene deposits of Maryland and Virginia.
They are doubtfully referred to Echinus.

Localities —Near South River and Severn River, Md.; Potomac Creek, Va.

Geologic horizon.—Aquia formation, lower Hocene.

Collection.—Johns Hopkins University (T 2000).

EOCENE ECHINODERMATA. 119

Subclass IRREGULARIA.

Order GNATHOSTOMATA.
Suborder CLYPEASTRINA.
Family FIBULARIID ©.
Genus ECHINOCYAMUS Phelsum.

EcurnocyamMus PARVUS Emmons.

Echinocyamus parvus Emmons, 1858, Agriculture Eastern Counties: North Carolina Geol. Survey Rept., p. 307, fig. 244.
Echinocyamus parvus Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 31.

Echinocyamus parvus Heilprin, 1884, Contrib. Tertiary Geology U.S., p. 17.

Echinocyamus parvus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.

Description and determinative characters—The location of Emmons’s type of this little
echinoid is unknown, and the writer has been unable to find any specimen similar to it in the
North Carolina miei studied. The description of Emmons is therefore quoted in full, as
follows:

Test small, oval, with rounded sides, avenues dorsal; mouth subcentral, rounded, large, with a crenulated margin;

?

vent between the:mouth and hinder margin; genital pores apparently four. The mouthis large in proportion to the size
of the body and the vent is situated halfway between the mouth and the margin.

Dimensions.—Emmons’s figure, which he states is natural size, is 5 millimeters in length and
3 millimeters in width.

Related forms.—E. parvus is closely allied to E. hualeyanus. The latter apparently differs,
however, in being more pointed anteriorly and in having the periproct near the posterior margin.
E. parvus is also closely related to E. vaughani and E. texanus, which are to be distinguished by
having the periproct nearer the peristome.

Locality —Craven County, N. C. (Emmons).

Geologic horizon.—Kocene (Emmons). Very probably from the Trent marl.

EcuINOCYAMUS HUXLEYANUS Meyer.

Plate LVII, figures la-d.

Echinocyamus huxleyanus Meyer, 1886, Alabama Geol. Survey Bull. 1, p. 85, Pl. III, fig. 23.
Echinocyamus hualeyanus De Gregorio, 1890, Mon. faune éocénique Mejseare, p. 251, Pl. XLITI, fig. 15.
Echinocyamus huxleyanus Stefanini, 1911, Soe. geol. italiana Boll., vol. 30, p. 697.

Determinative characters.—Test thin-walled and fragile, very small, flattened egg-shaped,
anterior end pointed. Upper surface low, convex; under surface concave around peristome.
Apical system excentric anteriorly, with four large genital pores. Petals rudimentary, open at
ends; pores not conjugated. Peristome central, relatively large. Periproct small, about one-
fourth the distance from margin to peristome. Tubercles relatively large.

Dimensions.—Length 3 to 5 millimeters; width 2 to 3 millimeters; height 1 to 2 millimeters.

Description.—This little Echinocyamus is found in some abundance in the sands of the
Claiborne group in Alabama. The test is notably thin-walled and fragile, in strong contrast
with the other American representatives of the genus. In marginal outline it is subelliptical to
elongate subovate and in general form subellipsoidal to flattened egg-shaped; the anterior end
being more or less pointed, and the height being about half or less than half of the width. The
upper surface is low and gently convex; the lower surface flattened, shghtly concave close to the
peristome.

The ambulacral petals are racanentery, extending two-thirds or more of the way to the
margin, open at the ends; poriferous zones nearly straight, pores round, pairs not conjugated.
The apical system is excentric anteriorly, with four large genital pores set close together, the
anterior pair being only slightly nearer together than the posterior pair.

120 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The surface of the test is covered with numerous small but rather conspicuous tubercles set
in relatively large scrobicules.

The peristome is central, relatively large, circular. The periproct is small, about one-half
the diameter of the peristome, situated near the margin, being about one-fourth of the distance
from the margin to the peristome.

Related forms.—E. huxleyanus is closely related to E. parvus. In fact, it is quite possible
that with the discovery of some good specimens of Emmons’s form H. hualeyanus may be found
to be identical and be reduced to a synonym. It appears to differ from EL. parvus, however, in
having its periproct nearer the margin and in being more pointed anteriorly. It also resembles
both £. texanus and E. vaughani, but differs from them in having thinner walls, in being less
elevated, and in not having its periproct near the peristome.

Locality.—Claiborne, Ala.

Geologic horizon.—Gosport sand, Claiborne group, middle Eocene.

Collections.—U. 8. National Museum (figured form); Johns Hopkins University (T 2006).

EcuINocyAMUS TEXANUs Twitchell, n. sp.
Plate LVII, figures 2a-d.

Determinative characters.—Test very small, ellipsoidal, oval in marginal outline. Upper
surface elevated, somewhat flattened in the center; lower surface flattened around the nearly
flush peristome. Apical system with four medium-sized genital pores; madreporite tumid.
Petals long, the anterior three nearly reaching the margin, wide open at ends. Peristome
relatively large, central; periproct very small, close to peristome.

Dimensions.—Length 5 millimeters; width 4 millimeters; height 2.5 millimeters.

Description.—Only a single specimen of this new Echinocyamus has been discovered. It
was found by Mr. T. H. Aldrich of Birmingham, Ala., who reports that it was found in the
“Lower Claiborne” deposits of Lee County, Tex. The test is thick-walled, very small Gt being
one of the smallest of American echinoderms), regularly oval in marginal outline, and ellipsoidal
in general form. The upper surface is elevated, somewhat flattened centrally; the lower sur-
face flattened near the nearly flush peristome amd the periproct.

The ambulacral petals are rather well defined, relatively long, all of about equal length,
the anterior three extending nearly to the margin as seen from above. The poriferous zones
diverge in almost straight lines to the ends where they are wide apart; they consist of small
round pores in pairs which are apparently not conjugated.

The apical system is subcentral or very slightly excentric anteriorly, coincident with the
apex, with four moderate-sized genital pores set near together, the anterior pair but slightly
nearer together than the posterior pair. A small, swollen, button-shaped madreporite just
reaches to the genital pores. ;

The peristome is relatively large, central, nearly flush with the lower surface; periproct
very small, about one-third of the diameter of the peristome, and is situated at a distance from
the peristome equal to its own diameter.

Related forms.—E. texanus is most closely related to E. vaughani, but is easily distinguished
from it by its less ege-shaped form, smaller size, less pointed anterior end, and less difference
between its longitudinal and transverse diameters. . tecanus also resembles HL. parvus and
E. huzleyanus but differs from both in haying its periproct near the peristome. It also differs
from E. huzleyanus in being less fragile, less depressed, and less a anteriorly.

Locality.—Lee Count Tex.

Geologic horizon.—Lower part of Claiborne group, middle Eocene.

Collection.— Johns Hopkins University (T 2002).

EOCENE ECHINODERMATA, > PAIL

Genus SISMONDIA Desor.
SIsMONDIA (?) PLANA Conrad.

Plate LVII, figures 4a-d.

Sismondia plana Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.

Mortonia (Periarchus) plana Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 21.
Sismondia plana Cotteau, 1891, Paléontologie francaise, Echinides éocénes, vol. 2, p. 299.
Monostychia plana Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 108.

Pervarchus (?) plana Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 699.

; Determinative characters.—Test very small, very thin, subovate to subcircular in marginal
outline, rounded to somewhat pointed anteriorly and posteriorly. Upper surface very low,
slightly tumid centrally; apex and apical system more or less anteriorly excentric; lower sur-
face flat; margin very thin. Ambulacral petals subelliptical, extending halfway to margin,
nearly closing at ends. Peristome slightly excentric anteriorly, small, circular; ambulacral
grooves well defined and simple halfway to the margin, then obscure but apparently not branch-
ing. Periproct very small, elliptical, about two-fifths the way from margin to peristome.

Dimensions.—Length 17 millimeters; width 15 millimeters; height 2 millimeters.

Description.—The test of this species is very small, rarely exceeding one-half an inch in
diameter, very thin throughout, subovate to subcireular in marginal outline, rounded to some-
what pointed anteriorly and posteriorly, broadest back of the middle. The upper surface is
very low, slightly tumid centrally; the apex usually excentric anteriorly, sometimes subcentral;
the lower surface flat; the margin very thin.

The ambulacral petals are well defined but small, extending only halfway to the margin,
broadly lanceolate to subelliptical in outline, nearly closing at the ends; several pairs of pores
extend beyond the ends of the petals. The poriferous zones are relatively narrow, inner row
of pores round, outer row oval, pairs of pores conjugated; interporiferous areas rather narrow,
not much wider than the poriferous zones.

The apical system is subcentral or excentric anteriorly, coincident with the apex. The
details could not be clearly made out on the specimens.

The tuberculation is inconspicuous, the whole test being covered with small tubercles, in
shallow scrobicules, set closely together.

The peristome is subcentral or slightly excentric anteriorly, small, circular. The ambula-
eral grooves extend as well defined simple lines from the peristome halfway to the margin, beyond
which point they become obscure; but do not appear to branch.

The periproct is very small, elliptical, the longest diameter being longitudinal, located about
two-fifths of the way from the margin to the peristome.

Related forms.—Scutella (?) conradiis closely related to Sismondia (?) plana but differs from
it in having its posterior border truncated and notched at the middle and opposite the posterior
petals, and its periproct nearer the posterior border.

Locality.—The type came from South Carolina. (No more definite locality can be given.)
‘Some specimens came from near Charleston, S. C.

Geologic horizon.—Kocene.

Collection.—Academy of Natural Sciences of Philadelphia (1080).

Genus FIBULARIA Lamarck.
FIBULARIA MERIDIONALIS (Meyer).

Plate LVII, figures 3a—-d.
Echinocyamus meridionalis Meyer, 1887, Fauna Alttertiiirs Mississippi und Alabama, p. 12, Pl. II, figs. 21, 21a.
Echinocyamus meridionalis De Gregorio, 1890, Mon. faune éocénique Alabama, p. 251, Pl. XLIII, fig. 14.
Echinocyamus meridionalis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.
Determinative characters.—Test thin walled and fragile, very small, discoidal, broadly oval
to subcircular in marginal outline. Upper surface very low, flat or nearly so; sides rounded;
lower surface slightly concave. Apical system central or subcentral; petals rudimentary,

129) MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

inconspicuous. Peristome central, unusually large, much larger than periproct, circular, with
crenulated margin. Periproct very small, nearer to posterior margin than to peristome.

Dimensions.—Length 2 to 4 millimeters; width 1.5 to 3 millimeters; height 0.5 to 1 milli-
meter.

Description.—This little echinoid occurs in comparative abundance in association with
Echinocyamus hualeyanus in the Gosport sand at Claiborne, Ala., and elsewhere. The test is
thin walled and fragile, very small, rarely reaching a quarter of an inch in length, discoidal in
general form, broadly oval to subcircular in marginal outline. The upper surface is very low,
rarely over a millimeter in height, flat or faintly convex; the sides rounded; the lower surface
nearly flat, or slightly concave. In a few specimens several faint radiating creases can be
distinguished on the lower side.

The ambulacral petals are decidedly rudimentary, so inconspicuous as to be difficult to
discern on even good specimens; short, extending less than halfway to the margin, the poriferous
zones nearly parallel and composed of very small pores in pairs which are not conjugated.

The apical system is central or subcentral, usually broken out. The genital pores are very
small and can rarely be made out on the specimens.

The whole surface of the test is covered with small tubercles, set in relatively large
scrobicules.

The peristome is central and unusually large in proportion to the size of the test, its diameter
being 4 or 5 times that of the periproct. The periproct is very small, circular, and situated from
one-fourth to one-third of the way from the posterior margin to the peristome.

Related forms.—F. meridionalis is not closely related to any other American species. In its
fragility, size, and superficial characteristics it resembles F. hualeyanus, but differs in having a
more rudimentary apical system and ambulacral petals and in its very low, subcircular, discoidal
form.

Localities.—Claiborne, Ala., and Jackson, Miss.

Geologic horizon.—Gosport sand of Claiborne group, middle Eocene.

Collections.—Johns Hopkins University (T 2005); U.S. National Museum.

Family LAGANID®.
Genus LAGANUM Blainville.
Lacanum (2) crusTULOIDES (Morton). :

Plate LVII, figures 5a—d, 6a-d.

Scutella crustuloides Morton, 1833, Am. Jour. Sci., Ist ser., vol. 24, p. 131, Pl. X, fig. 8.

Scutella crustuloides Morton, 1834, Synopsis Organic Remains Cretaceous, p. 77, Pl. XV, fig. 10.

Scutella crustuloides Morton, 1842, Acad. Nat. Sci..Philadelphia Jour., 1st ser., vol. 8, p. 217.

Scutella crustuloides Bronn, 1848, Index Paleontologicus, vol. 1, p. 1126; vol. 2, p. 196.

Scutella crustuloides Ravenel, 1848, Echinide, recent and fossil, of South Carolina, p. 2.

Scutella crustuloides Ravenel, 1850, Am. Assoc. Ady. Sei. Proc., vol. 3, p. 160.

Sismondia crustuloides Desor, 1858, Synopsis des échinides, p. 227.

Scutella crustuloides Gabb, 1859, Cat. Invert. Fossils Cretaceous, p. 19.

Scutella crustuloides Dujardin and Hupé, 1862, Histoire nat. zoophytes échinodermes, p. 559.

Sismondia crustuloides Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., pp. 74-75.

Sismondia crustuloides Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 21.

Scutella crustuloides De Gregorio, 1890, Mon. faune éocénique Alabama, p. 251, Pl. XLIII, figs. 24-25 (reprod. from
Morton).

Sismondia crustuloides Cotteau, 1891, Paléontologie francaise, Echinides éocénes, vol. 2, p. 300.

Scutella crustuloides Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77. z

Scutella crustuloides Boyle, 1893, U. 8. Geol. Survey Bull. 102, p. 262.

Periarchus (?) crustuloides Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 699.

Determinative characters —Test small, subpentagonal, suboval or subovate in marginal out-
line. Upper surface low, tumid centrally; margin very thick, submarginal area flat or nearly so,
about the same thickness as the margin. Lower surface concave. Apex and apical system
slightly excentric anteriorly. Ambulacral petals lanceolate, pointed and closed at the ends,

EOCENE ECHINODERMATA, 123

extending two-thirds the way to the margin; poriferous zones much narrower than interporif-
erous areas. Peristome small, subpentagonal, slightly excentric anteriorly; ambulacral grooves
simple, straight, inconspicuous. Periproct small, subcircular, from one-fourth to one-third the
way from margin to peristome.

Dimensions.—Specimen A: Length 21 millimeters; width 26 millimeters; height 5 milli-
meters. Specimen B: Length 31 millimeters; width 26 millimeters; height 6 millimeters.

Description.—This little echinoid was one of the first reported from American deposits,
having been described and figured by Morton as early as 1833. It is relatively somewhat abun-
dant in the Eocene deposits and has been found in South Carolina, Georgia, and Alabama. The
test is small, ranging.from three-quarters of an inch to 1} inches in length. In marginal outline
it is rather variable, being subpentagonal in most specimens but suboval or subovate in some.
The whole form is greatly depressed, the upper surface tumid centrally, the tumid area involving
the larger part or all of the ambulacral petals; the margin is rounded and notably thickened all
around, though slightly less so at the middle of the posterior end than elsewhere, the submarginal
area flat or nearly so, as thick as or more or less thick than the margin. The under surface is
decidedly concave, the concavity reaching nearly to the margin. The apex is slightly excentric
anteriorly at the summit of the tumid area.

The ambulacral petals are lanceolate or elongate subelliptical, pointed and practically closed
at the distal ends; the anterior pair slightly shorter than the other three, all of them extending
about two-thirds the way to the margin. The poriferous zones are very narrow, much narrower
than the interporiferous areas, sometimes irregular, the inner ends poorly defined, inner row of
pores round, outer row slitlike, pairs of pores conjugated. The whole surface of the test,
including the interporiferous areas and the apical region is covered with rather conspicuous
small tubercles set in deep scrobicules which are larger on the lower surface.

The apical system is central or slightly excentric anteriorly at the summit of the tumid area.
There are four large genital pores, the anterior pair being set closer together than the posterior
pair. The poriferous zones rarely if ever can be seen to come together at the proximal ends, and
the perforations of the radial plates, if they exist, can not be discerned.

The peristome is small, subpentagonal, slightly excentric anteriorly; the ambulacral grooves
are never very distinct on even well preserved specimens. They appear to be straight, simple,
faint lines from peristome to near the margin, distinguished more by finer tuberculation than
by the existence of a distinct groove.

The periproct is small, about one-third the diameter of the peristome, subcircular, situated
from one-fourth to one-third the way from the margin to the peristome.

Related forms.—Of American forms L. (?) crustuloides is most closely related to L. johnsoni
which differs chiefly in being higher and haying a thicker margin. _L. (?) erustuloides is also closely
related to L. floridanum which differs in having a smaller petaloidal area, a more regularly oval
marginal outline, a concave ring around the ends of the petals and a flat lower surface.
Scutella (?) conradi also resembles the present species but differs in having its margin thin and
posteriorly truncated and notched. L. archerensis and L. dalli both differ in haying flat lower
surfaces and the apical region but little if any higher than their thick margins.

Of foreign forms the present species is allied to Laganum reflecum from the Tertiary of
Blaye, France, which, however, is thinner posteriorly. Sismondia marginalis (Des Moulins)
Desor from the middle Eocene of France also resembles the present form but differs in having
petals which are longer and more open at the end.

Localities.—South Carolina, probably near Charleston; near Bainbridge, Ga.; Dethan, Ala.

Geologic horizon.—Jackson formation, (probably) upper Eocene; Vicksburg formation,
lower Oligocene.

Collections.—Boston Society of Natural History (S802a, A); U.S. National Museum (164,
744, B).

124 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.
Family SCUTELLIDA.
Genus SCUTELLA Lamarck.

Scutella Lamarck, 1816 (pars), Anim. sans vert., vol. 3, p. 7.

Scutella Lamarck, 1840, Anim. sans vert., 2d ed., vol. 3, pp. 275-277.
Scutella Agassiz, 1841, Mon. d’échinodermes, vol. 2, Des scutelles, p. 75.
Echinarachnius Gray, non Leske, 1825 (pars), Ann. Phil. for 1825, p. 428.
Echinarachnius Agassiz, 1872 (pars), Revision of the Hchini, p. 107.

The genus Scutella as here used includes the greatly depressed Scutellidee without lunules
or digitations; with central or subcentral apical system; homogeneous or slightly differentiated
plates: ambulacral furrows bifurcating; periproct marginal, a imareieal or actinal, but less
than two-fifths of the way from the margin; and four or five genital pores.

Some of the forms included here are ay certain authors placed under HEchinarachnius
Leske. This practice has not been followed by the writer because apparently Echimarachnius,
being founded in 1778 on Echinus placenta Linné, should replace the pre-Linnean name Arach-
saad Klein with which placenta was first associated by L. Agassiz in 1841, and because,
even if this correction is made, the writer also questions the giving of separate generic rank
to the forms with a strictly marginal periproct.

Genus SCUTELLA Lamarck.

SCUTELLA MISSISSIPPIENSIS Twitchell, n. sp.
Plate LIX, figures la-f, 2.

Determinative characters.—Test variable in size; subcircular to subtriangular in marginal
outline, broader than long, broadest posteriorly; the whole form greatly depressed, being thin |
and nearly flat around a narrow marginal area within which it rises very gradually and gently
to the low, central apex; margin thin, with a small notch in the middle of the posterior edge;
under surface flat. Ambulacral petals elliptical, extending about half way to the margin.
Apical system central. Peristome small, circular; ambulacral furrows simple and straight for
two-thirds or more of the way to the margin, then apparently forking symmetrically. Eoninect
very small, circular, almost at the ambitus though slightly Aniioarmenetnl, at the edge of the
notch in the middle of the posterior margin.

Dimensions.—Specimen A: Length 50 millimeters; width 52.5 millimeters; height 6
millimeters. Specimen B: Length 52.5 millimeters; width 76 millimeters; height 8 millimeters.

Description.—This new Scutella is one of the most abundant in the American Cenozoic
deposits. The writer has had opportunity to examine several hundr ed specimens. Nearly all
2 these were from the Eocene Coos of Mississippi, hence the specific name. The test is

ariable in size, ranging from less than 4 inch to over 3 inches in diameter and from less than
i "6 nearly 4 inch in height. The mar einal outline is also quite variable, ranging from circular
to subcircular in the younger forms to subtriangular and even transversely elliptical in the
larger forms. The whole form is much depressed, being thin and nearly flat around a narrow
saareinall area, although slightly more so posteriorly hea elsewhere, from which it rises gradu-
ally and gently to the low, central apex. The margin is thin evdl faintly undulating, wala a
small notch in the middle of the posterior edge; the under surface is flat except around the
peristome, where it is slightly concave. The apex is central or subcentral, at the summit of the
broad central tumid area.

The ambulacral areas are narrow in the petaloid region but wide in the marginal region
where they are wider than the interambulacral areas. The dorsal portions of the ambulacra
are petaloid. The petals are subequal in length, the odd petal shghtly longer and narrower
than the rest; elliptical in form, slightly open at the ends and extend about half way to the
margin. The poriferous zones are rather wide, about equal to the interporiferous areas, though

EOCENE ECHINODERMATA. 125

varying somewhat both among the petals on a single specimen or on different specimens, being
slightly wider, equal to, or slightly narrower than the interporiferous areas; the inner row of
pores oval, outer row slitlike, pairs of pores conjugated. A few pairs of pores occur beyond the
ends of the petals.

The interambulacral areas are large though somewhat smaller both between the petals and
at the margin than the ambulacral areas. The whole surface of the test is covered with small
uniform tubercles which are slightly larger on the under side. ;

The apical system is subcentral, at the summit of the central tumid area. The madre-
porite is relatively large, occupying the larger part of the area covered by the system, and flush
with the surface. There are five genital pores near the edge of the madreporite. One specimen
studied possessed the abnormal feature of a double posterior genital pore. There are five small
radial plates, each perforated by a minute pore.

The peristome is very small, not over double the size of the periproct, circular, central or
slightly excentric posteriorly; the ambulacral furrows simple and straight for two-thirds or
more of the distance from peristome to margin, then apparently forking symmetrically, each
pair of branches continuing almost to the margin. The under side is revealed on few specimens,
and on few can the furrows be made out.

The periproct is very small, circular, almost at the ambitus though slightly inframarginal,
situated at the under and inner edge of the notch in the middle of the posterior margin.

Related forms.—S. mississippiensis does not appear to be closely related to any other
American form. It resembles Periarchus lyelli in general appearance, and specimens have
doubtless been erroneously labeled S. lyelli in some collections; S. mississippiensis, however, is
readily distinguished by its submarginal periproct, greater width, the notch in its posterior edge,
and the fact that its tumid central area involves nearly the whole upper surface. It bears an
interesting resemblance to the recent species Scutella parma, but differs from it in having less
widely open petals, much narrower interporiferous areas, a less circular and more anteriorly
pointed form, and in not having its periproct exactly marginal or at the ambitus.

Of foreign forms S. patagonensis (Desor) Ortman, especially the ‘‘alate’’ form described by
Ortman and formerly known as Echinarachnius juliensis Desor from the Neocene of Patagonia,
appears to be most closely related to S. mississippiensis. It is very sumilar in marginal outline,
location of periproct, etc., but differs in having a less central apical system, longer petals, nar-
rower interambulacral areas, and in having its ambulacral furrows beginning simply and then
forking in symmetrical curving branches almost immediately. S.subtetragona De Grateloup and
S. striatula M. de Serres, both from the upper Eocene of France, also present certain points of
identity with S. mississippiensis. Each, however, differs from the American form in having
four genital pores instead of five and in having the ambulacral furrows fork near the peristome.

Locqlities—Cemetery Branch (type), Radiate Banks, Spillman’s Clam bed and other
localities in and around Enterprise, Clarke County, Miss.; San Augustin, and 1 mile southwest
of Palestine, Tex.

Geologic horizon.—Claiborne group, middle Eocene. In Mississippi, at the base of the
Lisbon marl. In Texas, in the marine substage of the Claiborne.

Collections.—U. 8. National Museum (137655, A; 137655a, B); Wagner Free Institute of
Science.

ScUTELLA TUOMEYI Twitchell, n. sp.

Plate LX, figures la—-d.

Determinative characters.—TYest medium in size, subovyate in marginal outline, somewhat
poirted anteriorly and truncated posteriorly; the whole form greatly depressed, being thin and
nearly flat around a narrow marginal area, and only slightly tumid within the petaloidal area;
under surface flat. Ambulacral petals narrowly elliptical, the posterior pair extending about
half, the others decidedly more than half way to the margin. Apex and apical system central,
at the summit of the tumid area. Peristome small, circular; ambulacral furrows simple and

39800°—15 9)

126 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

straight for about half the distance to the margin. Periproct very small, subcircular, about
one-fourth the way from the posterior margin to the peristome.

Dimensions.—Length 40.5 millimeters; width 39 millimeters; height 5 millimeters.

Description.—This new species is rare, only a single specimen having yet been discovered.
As this specimen was found in South Carolina, the form is named in honor of that distinguished
worker upon the geology and paleontology of South Carolina, Mr. M. Tuomey. The test is
medium in size. In marginal outline it is subovate, broadcst posteriorly, narrowing until some-
what pointed anteriorly, truncated along the middle of the posterior border. The whole form is
greatly depressed, being quite flat all around the area outside the ambulacral petals, and within
the petaloidal area rising only slightly to form a very low broad mound. The margin of the test
is thin, with two shallow notches opposite the ends of the posterior petals. The flattened mar-
ginal area, from the ends of the petals to the edge, is thin and rather narrow, especially ante-
riorly, where it is decidedly less wide than the petals are long, while posteriorly the width is
about equal to the length of the petals. The under surface is flat or slightly concave from
edge to edge. The apex is central or subcentral, at the summit of the tumid area.

The ambulacral areas are narrow in the petaloid region, but wide at the margin, where they
are wider than the interambulacral areas. The dorsal portions are petaloid. The petals are
of medium size, subequal in length, narrowly elliptical in form, slightly open at the ends; the
posterior pair extending about half, the others decidedly more than half, the way to the margin.
The poriferous zones are rather wide, almost as wide as the interporiferous areas; inner row of
pores oval, the outer slitlike; the pairs of pores conjugated. A few pairs of pores extend beyond
the ends of the petals.

The interambulacral areas are rather wide between the petals, wider than the ambulacral
areas; of nearly uniform width to the margin where somewhat narrower than the ambulacral
areas; composed of large polygonal plates. 'The whole surface of the test is covered with small
uniform tubercles, which are slightly larger on the under side.

The apical system is central or subcentral; coincident with the apex. The details are
indistinct upon the specimen; but the madreporite is relatively large, flush with the surface,
with five genital pores near its edge.

The peristome is small, circular or subcircular, subcentral; the ambulacral furrows appar-
ently simple and straight for about half the distance to the margin, where. they probably fork
symmetrically though they do not show well on the only specimen found.

The periproct is very small, about half the diameter of the peristome, subcircular, approach-
ing an inframarginal position, being situated on the under surface about one-fourth the way from
the posterior margin to the peristome.

Related forms.—This species is very similar to some specimens of Periarchus lyelli, but differs
from it in being more pointed anteriorly, in being truncated posteriorly, and in haying its
periproct nearer to its posterior border. S. conradi resembles S. tuomeyi, but can be separated
by its smaller size, subquadrate posterior end, emarginate posterior border, and nearer approach
of periproct to posterior border. S. tuwomeyr also resembles S. mississipprensis in general
appearance, but the latter is readily distinguished by the submarginal location of its periproct.
There do not appear to be any foreign forms which are closely related.

Locality.—Fourteen miles south of Fort Motte station, Orangeburg County, S. C.

Geologic horizon.—Kocene, probably from the McBean formation of the Claiborne group,
middle Eocene. The specimen occurred in a greensand matrix.

Collection. U. S. National Museum (137970).

ScurELLA (?) conrapr (Cotteau).
Plate LXIV, figures la-d.

non Scutella marginalis Desmoulins, 1837, Etudes sur les échinides, Tabl. synon., p. 234.

non Laganwm marginale, Agassiz and Desor, 1847, Cat. raisonné échinodermes, vol. 7, p. 133.
non Sismondia marginalis Desor, 1858, Synopsis des échinides, p. 226, Pl. XX VII, figs. 26-28.
Sismondia marginalis Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75, no fig.
Mortonia (Periarchus) marginalis Conrad, 1856, Smithsonian Misc. Col} vol. 7 (200), p. 21.

EOCENE ECHINODERMATA. 127

Sismondia conradi Cotteau, 1891, Paléontologie frangaise, Echinides éocénes, vol. 2, p. 300.

non Sismondia marginalis Cotteau, 1891, Paléontologie frangaise, Echinides éocénes, vol. 2, p. 267.
Monostychia marginalis Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 105.

Periarchus (?) marginalis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Determinative characters.—Test small in size; marginal outline subquadrate to suboval, the
sides and posterior margin being truncated so that the posterior border is semiquadrate and the
anterior border is semicircular; the whole form much depressed, though centrally it rises in the
form of a low gently rounded mound; margin thin, with a small notch in the middle of the pos-
terior edge; under surface flat. Ambulacral petals elliptical, extending about halfway to the
margin. Apex and apical system central, or slightly excentric anteriorly. Peristome small,
subcircular; ambulacral furrows simple and straight for over halfway to the margin, then becom-
ing obscure. Periproct very small, subpentagonal or subcircular, inframarginal.

Dimensions.—Length 21 millimeters; width 21 millimeters; height 3 millimeters. This is
Conrad’s type, here figured for the first time.

Description.—The species, though described by Conrad in 1865, has never been figured and
isnot very well known. There is some doubt in regard to its generic position. Gregory’s remark
that it should be transferred to the genus Monostychia is not agreed to, for the reason that the
type reveals five genital pores and fails to show any continuation of the actinal grooves abac-
tinally. The test is small in size, the type bemg about 42 inch in diameter and about } inch
in height. In marginal outline it is subquadrate to suboval, with the sides and posterior margin
truncated so that the posterior half of the border is semiquadrate and the anterior half semi-
circular. The upper surface is so much depressed all around the marginal area as to be quite
flat, or even slightly concave, but within the area covered by the ambulacral petals it rises in the
form of a low, gently rounded mound with a rather broad, flattened summit. The margin is thin,
though slightly thicker than the submarginal area, with a small notch in the middle of the pos-
terior side. The under surface is flat. The apex is central or slightly excentric anteriorly, at
the summit of the tumid central area.

The ambulacral areas are narrow in the petaloid region, wider in the marginal region; but
the condition of the specimen does not permit the making out of many details. The dorsal por-
tions of the ambulacra are petaloid. The petals are subequal in length, elliptical in form, slightly
open at the ends and extend about halfway to the margin. The poriferous zones are rather wide,
but slightly less so than the interporiferous areas; the inner row of pores oval, the outer slitlike;
the pairs of pores conjugated. A few pairs of pores occur beyond the ends of the petals.

The interambulacral areas are relatively large. The whole surface of the test is covered
with small uniform tubercles, which are slightly larger on the under side.

The apical system is subcentral, at the summit of the central mound. The madreporite is
relatively large, occupying the larger part of the area covered by the system, and faintly tumid.
There are five genital pores near the edge of the madreporite and five small radial plates each
perforated by a minute pore.

The peristome is small, subcircular, central; the ambulacral furrows simple, straight, and
quite distinct for slightly more than half the distance to the margin, then becoming obscure. A
small ridge extends from the peristome along the middle of each ambulacral furrow for a greater
distance than the diameter of the peristome.

The periproct is very small, considerably smaller than the peristome, subpentagonal or sub-
circular, situated on the under surface near the posterior margin, being about one-fifth the radius
from the border.

Related forms.—Of American forms S. (?) conradi most closely resembles S. fwomeyi and some
of the smaller specimens of Periarchus lyelli, but is easily separated from these species by its
subquadrate marginal outline and the inframarginal position of its periproct. It also resembles
S. mississippiensis, but its periproct is less nearly marginal. It does not appear closely related
to any of the known foreign forms.

Locality.—Conrad said his type came from near Charleston, S. C.

Geologic horizon.—Probably Cooper marl, upper Eocene.

Collection.—Academy of Natural Sciences of Philadelphia (1081).

128 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Genus MORTONELLA Pomel.
non Mortonia Gray, 1851.
Mortonia Desor, 1857, Synopsis des échinides fossiles, p. 231.
Mortonella Pomel, 1883, Classif. méthodique et généra des échinides vivants et fossiles, p. 70.
Mortonella Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 684.

The genus Mortonella as used here includes the scutella-like forms having a central or sub-
central apical system, periproct less than halfway from peristome to margin, thick margin, five
genital pores, and ambulacral area either flat or tumid. The general form is discoidal. The
ambulacral furrows are simple and straight for halfway to the margin, then bifurcate and proceed
to the margin without much further branching. The ambulacral petals extend slightly more
than halfway to the margin and are open at the ends. The chief difference between Mortonella
and Periarchus is in the thickness of the margin.

MorTONELLA QUINQUEFARIA (Say).
Plate LX, figures 2a-2f; Plate LXT, figures la-b.

Scutella quinquefaria Say, 1825, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 5, p. 228, no fig.

non Scutella rogersi Morton, 1834, Synopsis organic remains Cretaceous, p. 77, Pl. XIII, fig. 3

non Scutella rogersi Desmoulins, 1837, Etudes sur les échinides, Tabl. synon., p. 236.

non Lagana rogersi Agassiz, 1840, Cat. syst. ectyporum echinodermatum fossilium musei Neocomensis, p. 6. Merely
listed Morton’s form.

Scutella rogersi Agassiz, 1841, Mon. échinodermes vivans et fossiles, vol. 2, Des scutelles, pp. 85, 86, Pl. XIX,
figs. 1-4. Described and figured Say’s form under the impression that he was dealing with Morton’s.

Scutella rogerst Agassiz (pars), 1847, Cat. raisonné échinodermes, vol. 7, p. 135.

Scutella rogerst Bronn (pars), 1848, Index palzeontologicus, vol. 1, p. 1126; vol. 2, p. 196.

Mortonia rogersi Desor (pars), 1858, Synopsis des échinides fossiles, p. 231, no fig. Described Say’s form but cited Mor-
ton’s figure.

Mortonia rogersit Dujardin and Hupé, 1862, Hist. nat. des zoophytes échinodermes, p. 563.

Mortonia rogerst Conrad (pars), 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Mortonia quinquefaria (Say) Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 32.

Scutella rogersi Quenstedt, 1872-1875, Petrefact. Deutschlands, pt. 1, vol. 1, Echiniden, pp. 525, 546.

Mortonia rogersi Zittel, 1876-1880, Handbuch der palaeontologie, <i6ll 1, pt. 1, p. 522

Mortonia rogersi Agassiz, 1883, Tine Comp. Zoology Mem., vol. 10, No. 1. p. 88.

Mortonella rogersi Pomel, 1883, Classif. méth. et généra des Bchintides vivants et fossiles, Alger. »P. 70.

Scutella mortoni (Agassiz) Quenstedt, 1885, Handbuch der Petrefactenkunde, p. 696.

Scutella (Mortonia) rogersi De Gregorio (pars), 1890, Mon. faune éocénique bier, p. 250, Pl. XLITI, figs. 16-20.

Mortonia quinquefaria Gregory, 1891 (discussion), Geol. Soc. America Bull., vol. 3, p. 105.

Echinanthus quinquefaria Gregory, 1891 (tabulation), Geol. Soc. America Bull., vol. 3, p. 105. This was evidently a
lapsus calami.

Scutella rogerst Boyle, 1893, U. 8. Geol. Survey Bull. 102, p. 263.

non Mortonia rogersi Dana, 1895, Manual of geology, 4th ed., p. 898, fig. 1491.

Mortonella rogersi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 685.

Determinative characters —Test of medium size; discoidal; circular to broadly subovate in
marginal outline; much depressed, upper surface more or less tumid centrally, margin and sub-
marginal area thick; under surface flat. Ambulacral petals large, broad, spatulate, extending
nearly two-thirds of the distance to the margin. Apex and apical system subcentral. Peri-
stome small, circular; ambulacral furrows simple and straight nearly halfway to the margin,
then forking symmetrically. Periproct very small, circular, about half the distance from peri-
stome to posterior margin.

Dimensions —Specimen A: Length 56 millimeters; width 58 millimeters; height 14 milli-
meters. Specimen B: Length 59 millimeters; width 61 millimeters; height 8 millimeters.

Description.—This species was one of the earliest Cenozoic forms reported from American
deposits. It was first described by Thomas Say in 1825. Two specimens, which are probably
Say’s types, were found by the writer in the collection of the Academy of Natural Sciences of
Philadelphia. This species has been often confused with Clypeaster rogersi (Morton), owing partly
to a superficial resemblance, but more to the mistakes of L. Agassiz and Desor. Agassiz was the
first to figure Say’s form; but unfortunately having figured and described what was in reality

ECCENE ECHINODERMATA. 129

Say’s Scutella qguinquetaria he applied to the form Morton’s name Seutella rogersi. The forms
themselves are perfectly distinct, even belonging to different families, Say’s form being one of
the Scutilliidse and Morton’s one of the Clypeastride; but, owing to the mistakes mentioned
great confusion exists in regard to them in the various collections and in the literature. The
separation of the two forms is not at all difficult, Clypeaster rogersi (Morton) being easily distin-
guished by its straight unbranched ambulacral furrows, its more concave under surface, its more
tumid ambulacral petais, its less circular and more pentagonal marginal outline, and the location
of its periproct nearer the posterior border.

This species is also interesting because on it Desor founded his genus Mortonia, based chiefly
upon the unusually thick margin for a Scutella-like form. The name Mortonia was changed by
Pomel to Mortonella because Gray had applied the name Mortonia to a different genus prior to
Desor’s use of it for the present genus.

The test of the present species is notably discoidalin form. It is of medium size, the dimen-
sions varying but slightly from those already given. In most specimens it is usually circular in
marginal outline, though in some it is broader posteriorly than anteriorly. The whole form is
much depressed, the upper surface being either nearly flat or having a low, gently rounded cen-
tral mound involving only about half of the region covered by the ambulacral petals. The vari-
ations in marginal outline and tumidity of the upper surface seem almost of specific value,
but intermediate forms show a gradation from one to the other, and the variation in
the character of the upper surface occurs in both the forms which are circular in marginal
outline and those which are broader posteriorly. The region involving the outer part of each’
petal is faintly concave. The margin and submarginal area are thick, usualiy almost as thick as
the average thickness of the test; the margin being slightly thinner and less rounded posteriorly
than anteriorly, faintly undulating. The under surface is flat or broadly and faintly concave.
The apex is subcentral, or slightly excentric anteriorly, at the summit of the more or less tumid
central area. ;

The ambulacra are relatively wide in the petaloidal region, broader in the marginal region
where they about equal the interambulacral areas. The dorsal portions are petaloid; the petals
large, broad, subequal in length, the odd petal being slightly longer than the rest, spatulate in
form, open at the ends and extending nearly two-thirds the distance from the center to margin.
The poriferous zones are very wide, wider than the interporiferous areas; the inner row of pores
nearly straight and composed of oval openings, the outer row slitlike; the pairs of pores
conjugated.

The interambulacra are relatively narrow in the petaloidal region, wide in the marginal
region, where about equal to the ambulacral areas, composed of large polygonal plates. The
whole surface of the test, including the margins, is covered with small uniform tubercles which
are slightly larger on the under side.

The apical system is subcentral or slightly excentric anteriorly at the summit of the test.
The madreporite is relatively large, occupying the larger part of the area covered by the system
and flush with the surface. There are five large genital pores near the edge of the madreporite
and five small radial plates each perforated by a small pore.

The peristome is small, circular, central, the ambulacral furrows simple and straight nearly
half the distance to the margin, then forking symmetrically, each pair of branches continuing
almost to the margin. Each branch gives off on the outside one side branch at right angles about
a fourth of the radius from the margin, which side branches soon bend and in turn approach the
margin. A small ridge extends along the middle of each ambulacral furrow from the peristome
to the fork in the furrow.

The periproct is very small, circular, situated on the under surface about half the way from
the peristome to the posterior margin.

Related forms.—The thick margin and discoidal form of Mortonella quinquefaria afford a ready
means of separating it from most American echinoids. Dendraster perrini is similar in having
a thick margin but differs in having its apical system posteriorly excentric, its ambulacral

130 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

petals relatively longer and wider open at the ends, and its periproct inframarginal. Peri-
archus lyelli also resembles M. quinquefaria in general but has a thin margin. Of foreign forms
Scutella faujasi De France from the middle Tertiary of France is closely related to this species.
The specimen S. faujasi figured by Bronn in Lethxea geognostica, Plate XXXVI, figure 8,
shows the thick margin, discoidal outline, and similarly branching ambulacral furrows.

Localities—Near Milledgeville (Say’s types); 1 mile southwest of Sandersville (figured
specimen A); Washington County (figured specimen B); 14 miles northeast of Tenville; Nor-
ton; and 24 miles south of Warthen, Washington County, Ga.

Geologic horizon.—Claiborne group, middle Eocene, and Jackson formation,(?) upper
Eocene.

Collections.—U. S. National Museum (9500, A); Academy of Natural Sciences of Phila-
delphia: Wagner Free Institute of Science; Geological Survey of Georgia; Amherst College (B).

Genus PERIARCHUS Conrad.

Periarchus Conrad, 1866 (subgenus), Smithsonian Misc. Coll., vol. 7 (200), p. 21.
Periarchus Grabau and Shimer, 1910, North Am. index fossils, vol. 2, p. 591.
Periarchus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 687.

The genus Periarchus as used here includes the Scutella-lhke forms with central or sub-
central apical system, periproct actinal, but less than three-fifths of the way from the peristome
to the margin, thin margin, five genital pores and more or less abruptly tumid ambulacral area.

-The ambulacral furrows are usually simple and straight about halfway to the margin, then
bifurcate and proceed to tne margin without much further branching. The ambulacral petals
are usually short, rarely extending more than halfway to the margin, more or less open at the ends.

PERIARCHUS ALTUS Conrad.

Plate LVIII, figures la-e.

Scutella sp. Emmons, 1858, Agriculture Eastern Counties: North Carolina Geol. Survey Rept., p. 308, figs. 247, 248.
Sismondia alta Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., pp. 74, 75, no figure.

Mortonia (Periarchus) altus Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 21.

Mortonia (Periarchus) altus Heilprin, 1884, Contr. Tertiary geology U.S., p. 17.

Sismondia alta Cotteau, 1889-1894, Paléontologie frangaise, Echinides éocénes, vol. 2, p. 300.

Periarchus altus Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 105.

Periarchus altws Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 699.

Periarchus sp. 6 Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 699.

Determinative characters.—Test of medium size, circular in marginal outline, much depressed,
less so centrally where it rises in a relatively high, broad, obliquely flattened mound, whose apex
is noticeably excentric anteriorly; margin of sides and posterior end thin, anteriorly the upper
surface declines in a straight line from apex to edge; under surface flat. Ambulacral petals
subelliptical, relatively large, extending about halfway to the margin. Apical system slightly ex-
centric posteriorly, and well to the rear of the apex. Peristome small, circular, slightly excentric
posteriorly; ambulacral furrows simple and straight for slightly more than half the way to the
margin, then forking symmetrically. Periproct very small, subcircular, about two-fifths the
way from the peristome to the posterior border.

Dimensions.—Length 57.5 millimeters; width 59 millimeters; height 12 millimeters. This
is the type, refigured.

Description.—This species was figured and partly described by Emmons as early as 1858. He
placed it in the genus Scutella but did not give the form a specific name. In 1865 Conrad, who had
seen Emmons’s type, gave a good description of it and applied the appropriate specific name
alta but he did not figure it. It is rare, only the one specimen found by Emmons having yet
been reported. The test is of medium size. The marginal outline is circular. The upper sur-—
face rises centrally in the form of a low broad mound, whose apex is noticeably forward of the
center; anteriorly the surface declines in a straight line from the apex to the edge; along the
posterior margin it is greatly depressed and nearly flat from the edge to the petaloid region, then
rises at first rather steeply then more gently to the apex. The relative height of the central

EOCENE ECHINODERMATA. 131

mound is greater than in most forms likely to be confused with it, being more than one-fifth of
the diameter of the test. The margin of the sides and posterior end is thin. The under surface
is flat, or faintly concave between the margin and the region around the peristome. The apex
is noticeably excentric anteriorly at the summit of the tumid area.

The ambulacral areas are relatively wide in the petaloid region though wider in the mar-
ginal region, in both cases bemg wider than the interambulacral areas. The dorsal portions of
the ambulacra are petaloid. The petals are relatively large and broad; subequal in length, the
posterior pair being slightly shorter than the rest; subelliptical in form; slightly open at the
ends; extending slightly more than halfway to the margin. The poriferous zones are rather
wide, but less so than the wide interporiferous areas; the inner row of pores oval, outer row slit-
like; pairs of pores conjugated. A few pairs of pores occur beyond the ends of the petals.

The interambulacral areas are relatively small between the petals and though wide near the
margin in both cases are smaller than the ambulacral areas; composed of large polygonal plates.
The whole surface of the test is covered with small uniform tubercles, which are slightly larger
on the under side.

The apical system is slightly excentric posteriorly, located well back of the apex on a flat-
tened area which extends obliquely downward and backward from the apex and is about three
times the diameter of the system. The madreporite is relatively large, occupying the larger
part of the area covered by the system, subpentagonal, flush with the surface. There are five
large circular genital pores perforating the basal plates at the points of the madreporic pentagon,
and five small radial plates, each perforated by a minute pore.

The peristome is small, circular, slightly excentric posteriorly; the ambulacral furrows
simple and straight for sightly more than half the distance to the margin, then forking symmet-
rically, and at rather a wide angle, each pair of branches continuing nearly to the margin. A
small ridge extends out for a short distance from the peristome along the middle of each ambula-
cral furrow.

The periproct is very small, subcircular, situated on the under surface about two-fifths
of the way from the peristome to the posterior border. It is nearer the peristome than are
the forks in the ambulacral furrows.

Related forms.—The species is most closely related to P. lyelli, from which, howeyer, it is
easily distmguished by its anteriorly excentric apex, by the noncoincidence of its apical system
and apex, by the fact that the central tumid mound involves nearly the whole upper surface
instead of being confined to the petaloid region, and by its broader petals. No foreign forms
appear to be closely related to this species.

Locality.—Core Creek, Crayen County, N. C.

Geologic horizon.—Trent marl, middle Eocene.

Collection.— Williams College.

PERIARCHUS LYELLI Conrad.
Plate LXI, figures 2a-f; Plate L-XII, figures la—c, 2a-d.

Scutella lyelli Conrad, 1834, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 7, p. 152, no figure.

?Scutella lyelli Morton, 1834, Synopsis organic remains Cretaceous, p. 77, Pl. X, fig. 8. Figure shows upper surface
only; no description.

Scutella lyelli Conrad, 1842, Nat. Inst. Promotion Sci. Proc., 2d Bull., p. 175.

?Scutella lyelli Bronn, 1848, Index palzeontologicus, vol. 1, p. 1126; vol. 2, p. 196. Based on Morton.

?Sismondia lyelli Desor, 1858, Synopsis des échinides, p. 227. Based on Morton.

non Scutella lyelli Emmons, 1858, Agriculture Eastern Counties, North Carolina Geol. Survey Rept., p. 308, text fig. 246.

2Seutella lyelli Gabb, 1859, Cat. invert. fossils Cretaceous, p. 19. Based on Morton.

?Scutella lyelli Dujardin and Hupé, 1862, Hist. nat. zoophytes échinodermes, p. 559. Based on Morton.

Sismondia lyelli Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Mortonia (Periarchus) lyelli Conrad, 1866, Smithsonian Mise. Coll., vol. 7 (200), p. 21.

2Scutella lyelli Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 89. Based on Morton.

non Scutella lyelli Heilprin, 1884, Contrib. tertiary geology U.S. p. 17.

- Seutella lyelli Smith and Johnson, 1887, U. 8. Geol. Survey Bull. 43, p. 21.

2Sismondia lyelli Cotteau, 1889-1894, Paléontologie francaise, Echinides Gocénes, vol. 2, p. 301. Based on Morton.

UBD MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Scutella lyelli De Gregorio, 1890 (pars), Mon. faune éocénique Alabama, pp. 250-251, Pl. XLIII, fig. 21. Conrad’s
description but Morton’s figure.

Scutella lyelli Clark, 1891, Johns Hopkins Univ. Cire., vol. 10, No. 87, p. 77.

?Scutella lyelli Boyle, 1893, U. S. Geol. Survey Bull. 102, p. 263. Based cn Morton.

Periarchus sp. a. Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 696.

?Sismondia (?) lyelli Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Determinative characters.—Test variable in size, subcircular to subovate in marginal outline;
much depressed, less so centrally where it rises in a gently rounded, convex mound of variable
height; margin and wide submarginal area thin; under surface flat. Ampbulacral petals sub-
elliptical to suboblong, extending about half way to the margin. Apex and apical system central
or subcentral, on the somewhat flattened summit of the tumid area. Peristome small, subcir-
cular; ambulacral furrows simple and straight for about half way to the margin, then forking
symmetrically. Periproct very small, subcircular, from one-third to slightly more than halfway
from peristome to posterior border.

Dimensions.—Specimen A: Length 90 millimeters; width 90 millimeters; height 12 miulli-
meters. Specimen B: Leneth 32 millimeters; width 31 millimeters; height 6 millimeters. Speci-
men C: Length 35 millimeters ; width 34 millimeters; height 5 millimeters.

Description.—Considerable confusion exists in regard to this and allied forms in the various
collections and in the literature. Conrad as early as 1834 gave an excellent description of the
species but no figure. The same year Morton published a poor upper view only of a small form
which he called Scutella lyelli Conrad, but gave no description. Conrad’s form was a large
specimen from Alabama, forms similar to which have easily been identified among the material
studied by the writer. Morton’s specimen was a small one, whose present whereabouts is
unknown, and was from a locality which is uncertain. Desor, Cotteau, and others, basing their
action upon Morton’s figure, have placed the species lyelli in the genus Sismondia. This is an
error, as Conrad’s form has all the characters of Periarchus. Unless his figured specimen is dis-
covered, Morton’s form must remain of doubtful character and is therefore placed among the
doubtful and unrecognized species.

Periarchus lyelli is one of the most abundant of the American Cenozoic forms, at times occur-

ring in such numbers and with such constancy as to afford a valuable aid im determining the
geologic horizon in which it is found. The test is variable in size, ranging from 1 to 34 inches in
diameter. In marginal outline it is circular or subcircular to subovate, some specimens slightly
others decidedly broader posteriorly than anteriorly. All around the area outside the ambulacral
petals it is greatly depressed and quite flat; but within the petaloidal area it rises in the form of a
gently rounded mound with more or less flattened summit, which ranges from } to 4 inch in height
according to the size and age of the specimen. Sometimes the mound approaches a subconical
form, but even then the sides are more or less convex. The margin of the test is thin and slightly
undulating, both characters being most pronounced posteriorly; usually there are broad shallow
notches opposite the ends of the posterior petals, though these may be inconspicuous or absent
in the smaller specimens. The flattened marginal area, from the ends of the petals to the edge,
is thin and wide, being about as wide as, or wider than the petals are long, and usually widest
posteriorly. The under surface is flat. or nearly so with a broad faintly depressed ring about
midway between margin and peristome. The apex is central or slightly excentric anteriorly, at
the summit of the tumid area.
The ambulacral areas are narrow in the petaloid region but wide at the margin where they
about equal the interambulacral areas. The dorsal portions are petaloid. The petals are of
medium size; subequal in length, the odd petal being slightly longer than the rest; subelliptical
to elongate elliptical or suboblong in form; slightly open at the ends; extending half or slightly
more or less than half the way to the margin. The poriferous zones are rather wide, almost as
wide as the interporiferous areas; inner rows of pores nearly straight and parallel and formed of
oval pores, outer rows of pores slitlike; pairs of pores conjugated. A few pairs of pores occur
beyond the ends of the petals.

The interambulacral areas are large, relatively wide between the petals (usually wider
than the ambulacral areas), nearly uniform, and composed of large polygonal plates. The

7 EOCENE ECHINODERMATA. 133

whole surface of the test is covered with small uniform tubercles which are slightly larger on
the under side.

The apical system is central or slightly excentric anteriorly, on the somewhat flattened sum-
mit of the central mound. The madreporite is relatively large, oceupying the larger part of the
area covered by the system and flush with the surface. There are five genital pores near the
edge of the madreporite and five small radial plates each perforated by a small elliptical pore.

The peristome is small, subeircular, central or slightly excentric anteriorly; the ambulacral
furrows simple and straight for from one to two-thirds the distance to the margin, then forking
symmetrically at an angle usually of about 45°, each pair of branches continuing almost to the
margin. On well-preserved specimens, each branch may be seen to give off on the outside one
important side branch at right angles about halfway between the fork and the margin, which side
branches soon bend and in turn approach the margin. A small ridge extends out from the
peristome for a short distance along each ambulacral furrow.

The periproct is very small, about half the diameter of the peristome, circular or subcircular,
situated on the under surface from one-third to slightly more than one-half the way from the
peristome to the posterior border.

Related forms.—This species presents so many variable features that several apparently dis-
tinct varieties of it might have been recognized and separately described—such as one with a
transversely elongate subtriangular marginal outline, or one with periproct midway between
margin and peristome—but in each case intermediate forms show a gradation between the
possible variety and typical representatives of the species. P. /yelli Conrad is closely related
to the American forms P. pileus-sinensis and P. protuberans, both of which, however, have a
relatively higher and more conical central tumid area. P. protuberans is further distinguished
by its characteristic swollen anterior interporiferous area and smaller petaloid area. P. Lyelli
also greatly resembles S. twomeyi which, however, differs in being somewhat truncated posteri-
orly and in having its periproct nearer the posterior border. In superficial characters P. Lyelli
greatly resembles S. mississippiensis, but the latter is easily separated by the inframarginal
position of its periproct. It does not appear to be closely related to any of the foreign forms.

Localities —Near Claiborne (Conrad’s type and our specimen A); Cedar Creek, Clarke
County; St. Stephens, near Cocoa, Choctaw County; and Clarksville, Ala.; Shubuta Creek,
23 miles north of Shubuta; Chickasawhay River, near Shubuta; and Shell Prairie, near Pachuta,
Miss.; 14 miles below Macon, Twiggs County, Ga.; Mount Enterprise, Rusk County, and 2
miles east of Alto, Cherokee County, Tex.; Castle Hayne (specimen B); City Rock Quarry,
Smith Creek; and Rocky Point, near Wilmington, N. C.

Geologic horizon.—Claiborne group (middle Eocene) and Jackson formation (upper Eocene).
In Texas in the “‘marine substage”’ of the Claiborne. In Mississippi probably near the base of
the Lisbon marl. In Alabama abundant in the Scutella zone at the base of the Jackson, ‘just
above the Claiborne fossiliferous sand.’’ In North Carolina, in the Castle Hayne limestone
(upper Eocene or Oligocene).

Collections —Boston Society of Natural History (larger figured form) (1553, A); U. S.
National Museum (smaller figured form); Alabama Geological Survey; American Museum of
Natural History; Wagner Free Institute of Science; Williams College; Amherst College; Johns
Hopkins University (T 2003, B; T 2004, C).

PERIARCHUS PROTUBERANS Twitchell, n. sp.
Plate LXII, figures 3a-f.

Determinative characters—Test of medium size, subcircular in marginal outline; much
depressed, less so centrally where it rises in a high, slightly asymmetric cone; margin very
thin, broadly dentate posteriorly; under surface flat. Ambulacral petals elliptical, very small,
extending about one-third the distance from center to margin. The anterior interporiferous
area swollen near the apical system which is slightly excentric posteriorly and inclined down-
ward and backward from the subcentral apex. Peristome very small, circular, in a slight con-
cavity; ambulacral furrows simple and straight for about half way tc the margin, then forking

134 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

symmetrically. Periproct very small, oval or subovate, on the under surface about one-fourth
the distance from the peristome to the posterior margin.

Dimensions.—Length 54 millimeters; width 53 millimeters; height 9 millimeters.

Description.—This new species is one of the handsomest of American scutellid forms. It
is very delicate and fragile and so thin that it is translucent from the edge halfway to the center.
It is a rare form, not over half a dozen individuals having been reported, all of which are from
the Eocene deposits of Mississippi, where it occurs in association with P. pilews-sinensis and
P. lyelli. The test is of medium size, ranging from 14 to 2} inches in diameter; and subcircular
in marginal outline. All around the area from the edge near rly to the petals it is greatly depressed
and nearly flat; but within and slightly beyond the petaloidal area it rises in the form of a high,
slightly unsymmetrical cone which varies in height from 3 to $ an inch. The margin of the test
is very thin all around, almost like a knife edge, and is decidedly undulating, or zigzag, especially
posteriorly, where it is broadly dentate. The under surface, though for the most part flat, is
slightly and broadly concave around the margin and the peristome. The apex is subcentral
at the summit of the central cone.

The ambulacral areas are narrow in the petaloid region but wide in the marginal region
where they about equal the interambulacral areas. The dorsal portions are petaloid. The
petals are subequal in length, the odd petal slightly longer than the rest; relatively quite small,
extending only about two-fifths the distance from center to margin, the total area covered by
the petals being noticeably less than in most similar forms. The petals are elliptical in form
and nearly closed at the ends; the poriferous zones rather wide though less so than the inter-
poriferous areas, widest at their distal ends; the inner row of pores oval, outer row slitlike; the
pairs of pores conjugated. The anterior interporiferous area is swollen near the apical region
so as to form a small, narrow protuberance, confined within the interporiferous area, largest
nearest the apical system and constituting the apex of the test. This protuberance is one of
the most striking and most distinctive features of the form; and suggested the specific name.

The interambulacral areas are large, nearly uniform, and composed of large polygonal
plates. The whole surface of the test is covered with small uniform tubercles which are slightly
larger on the under side.

The apical system is slightly excentric posteriorly, inclined downward and backward from
the swollen anterior interporiferous area, on the steep posterior slope of the central subconical
mound. The madreporite is relatively large, occupying the larger part of the area covered by
the system. There are five genital pores near the edge of the madreporite, and five small radial
plates, each perforated by a small elliptical pore.

The peristome is very small, not much larger than the periproct, ‘circular, central, in a slight
concavity; ambulacral furrows ciple and straight for about one-half the dlsen nes from peris-=
tome to margin, then forking symmetrically, each pair of branches continuing nearly to the
margin and each branch giving off one important side branch at right angles at one-third to one-
fourth radius length from the margin; these side branches soon bend and in turn approach the
margin. A small ridge extends for a short distance along the middle of each ambulacral furrow.

The periproct is very small, oval or subovate in outline, the round end being nearest the
peristome, on the under surface from one-fourth to one-third the distance from peristome to the
posterior margin. It is much nearer the peristome than are the forks in the ambulacral furrows.

Related forms.—P. protuberans is very similar in appearance to P. pileus-sinensis (Ravenel),
resembling it more closely than it does any other American form. It is, however, readily dis-
tinguished by its protuberant anterior interporiferous area, smaller petaloidal area, the position
of its apical system to the rear of the apex, its thinner marginal area, smaller peristome, and the
nearer approach of its periproct to the peristome. No foreign forms appear to be closely related
to this species.

Localities —Shubuta Creek, 24 miles north of Shubuta (type), and Chickasawhay River,
Shubuta, Miss.

Geologic horiz son formation, upper Eocene.

Collection.—U. S. National Museum (164685).

BOCENE ECHINODERMATA. 135

PERIARCHUS PILEUS-SINENSIS (Ravenel).
Plate LXIII, figures la-e, 2a-d.

Scutella pileus-sinensis Ravenel, 1844, Acad. Nat. Sci. Philadelphia Proc., vol. 2, p. 97-98, no figure.
Scutella pileus-sinensis Ravenel, 1850, Am. Assoc. Adv. Sci. Proc., vol. 3, p. 160.

Sismondia pileus-sinensis Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Mortonia (Periarchus) pileus-sinensis Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 21.
Periarchus pileus-sinensis Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 105.

?Scutella caput-linensis Kennedy, 1891, Texas Geol. Survey Third Ann. Rept., pp. 55, 56.
2Scutella caput-sinensis Kennedy, 1895, Acad. Nat. Sci. Philadelphia Proc., pp. 113, 114, 115.
Periarchus pileus-sinensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 688.

Determinative characters.—Test of medium size, subcircular in marginal outline, much
depressed, less so centrally where it rises in a high well-defined cone with straight or concave
sides; margin and submarginal area thin; under surface flat. Ambulacral petals elongate-
elliptical, extending more than halfway to the margin. Apical system, central or slightly excen-
tric anteriorly, forming the summit of the central conical area. Peristome small, circular, ambu-
lacral furrows simple and straight for more than one-third of the distance to the margin then
forking symmetrically. Periproct very small, subcircular, slightly more than one-third the way
from peristome to posterior border.

Dimensions.—Specimen A: Length 79 millimeters; width 76 millimeters; height 16 milli-
meters. Specimen B: Length 654 millimeters; width 67 millimeters; height 14 millimeters.

Description.—This species was first described by Ravenel from the Eocene deposits of South
Carolina in 1844. His name, pileus-sinensis or ‘‘Mandarins hat,” is most appropriate for the
form, as may readily be seen by a glance at the side view. The form is rather abundant in certain
localities, sometimes occurring in association with Periarchus lyelli and Periarchus protuberans.
The test is of medium size, ranging from 2} to 3} inches in diameter. In marginal outline it is
almost circular, though shghtly broader posteriorly than anteriorly. All around the area outside
the ambulacral petals it is greatly depressed and nearly flat; but within the petaloidal area it rises
in a high well-defined cone with straight or concave sides. The height of the cone is somewhat
variable but in the larger forms it usually rises to over half an inch. The margin of the test is
thin and slightly undulating, both characters being most pronounced posteriorly. In some
specimens the submarginal area is thinner than the edge. There is usually a more pronounced
notch in the margin opposite the ends of the posterior paired ambulacral petals. The under sur-
face is flat, even faintly concave between the margin and the region around the peristome. The
apex is slightly excentric anteriorly, at the summit of the central conical area.

The ambulacral areas are narrow in the petaloid region, wider in the marginal region where
they equal or slightly exceed the width of the interambulacral areas. The dorsal portions are
petaloid. The petals are subequal in length, the anterior paired petals being slightly shorter
than the other three; elongate elliptical in form; extending more than halfway to the margin,
the odd petal usually approaching the margin more nearly than the rest; slightly open at the
ends. The poriferous zones are rather wide, about equal to the interporiferous areas; the inner
row of pores oval, the outer slitlike; the pairs of pores conjugated. A few pairs of pores occur
beyond the ends of the petals.

The interambulacral areas are large, nearly uniform, and composed of large polygonal plates.
The whole surface of the test is covered with small uniform tubercles, which are slightly larger
on the under surface.

The apical system is subcentral or slightly excentric anteriorly at the summit of the conical
area. The madreporite is relatively large, occupying the larger part of the area covered by the
system and is somewhat tumid. There are five genital pores near the edge of the madreporite
and five small radial plates each perforated by a small elliptical pore.

The peristome is small, circular, central or slightly excentric anteriorly; ambulacral furrows
simple and straight for more than one-third the distance from peristome to margin, then forking
symmetrically, each pair of branches continuing nearly to the margin, each branch giving off
one important side branch at right angles at a point from one-third to one-fourth the radius of

136 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

the test from the margin, which side branches soon bend and in turn approach the margin. A
small ridge extends along the center of each ambulacral furrow for a short distance away from
the peristome.

The periproct is very small, subcircular, on the under surface at a little more than one-third
the distance from the peristome to the posterior margin. It is sometimes nearer, sometimes
farther from the peristome than are the forks in the ambulacral furrows.

Related forms.—P. pileus-sinensis is very closely related to P. lyelli and P. protuberans.
From the former it is best distinguished by its higher and straight or concave-sided central cone;
and from the latter by its incline the swollen anterior iteeeorii one area at the apex. No
foreign forms appear to be closely related to this species.

Localities —The type was from ‘‘about 6 miles south of Black Oak Lock of the Santee Canal,
St. Johns Parish, S. C.” The figured specimen came from ‘‘the Santee Canal, 8. C.” Other
localities are Santee River, S. C.; near Tivoli, Beachhaven Park, Limestone Creek, Towers, Rich
Hill, Crawford County ; Shellstone Creek, 2 miles south of Perry, Houston County; and Ring Jaw
Landing, Oconee River, Ga.; 1 mile west of Cocoa, Choctaw County; and Claiborne and below
mouth of Cedar Creek, Clarke County, Ala.; Chickasawhay River at Shubuta, Shubuta Creek, 24
miles north of Shubuta, and Shell Prairie near Pachuta, Miss.

Geologic horizon.—Jackson formation, upper Eocene. In South Carolina in the Cooper
marl, of Jackson age. In Georgia in the Vicksburg or Jackson formation.

Collections. 2ay. S. National Museum (5133, A; 137791, B); Amherst College; Boston
Society of Natural History ; American Museum of Natural Shetome: University of South Carolina.

Family CLYPEASTRIDZX.
Genus CLYPEASTER Lamarck.

CLYPEASTER ROGERSI (Morton).
Plate LXIV, figures 2a-d, 3a-d.

Scutella rogersi Morton, 1834, Synopsis organic remains Cretaceous, p. 77, Pl. XIII, fig. 3.

Lagana rogersi Agassiz, 1840, Cat. syst. ectyporum Echinodermatum fossilium musei Neocomensis, p. 6. Merely
listed Morton’s form.

non Scutella rogersi Agassiz, 1841, Mon. échinodermes vivans et fossiles, vol. 2, Des scutelles, pp. 85, 86, Pl. XIX,
figs. 1-4. Described and figured Mortonella quinquefaria (Say) under the impression that he was dealing with
Morton’s form.

Scutella rogersi Morton, 1842, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 8, p. 218.

Scutella jonesti Forbes, 1845, Geol. Soc. London Proc., vol. 4, p. 574, text figure.

Scutella jonesti Forbes, 1845, Geol. Soc. London Quart. Jour., vol. 1, p. 440, text figure.

Scutella rogersi, Agassiz (pars), 1847, Cat. raisonné échinodermes, vol. 7, p. 135.

Scutella rogersi Bronn (pars), 1848, Index palzeontologicus, vol. 1, p. 196; vol. 2, p. 1126.

Scutella jonesiti Bronn, 1848, Index palzontologicus, vol. 1, p. 196; vol. 2, p. 1126.

Clypeaster jonesti Desor, 1858, Synopsis des échinides fossiles, p. 243.

Mortonia rogersi Desor (pars) (figure cited only), 1858, Synopsis des echinides fossiles, p. 231.

Scutella rodgerst Gabb, 1859, Cat. invert. fossils Cretaceous, p. 19.

non Clypeaster ambigenus Michelin, 1861, Soc. géol. France Mém., 2d ser., vol. 7, p. 113.

Clypeaster jonesti Dujardin and Hupé, 1862, Hist. nat. zoophytes échinodermes, p. 573.

Mortonia rogersi Conrad (pars), 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Mortonia jonesii Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Mortonia turgida Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., vol. 17, p. 184, no figure.

Clypeaster jonesti Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

? Mortonia tumida Conan, 1866, Smithsonian Misc. Coll., vol. 7 (200), PP. 22, 37 (note).

Clypeaster jonesii Conrad, 1866, Smithsonian Misc. Coll., volt 7 (200), p.

? Clypeaster tumidus Conrad, 1866, Smithsonian Mise. Coll., vol. 7 (200), p pp. 22, 37 (note).

Clypeaster rogersi Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 22

Scutella (mortonia) rogersi De Gregorio (pars), 1890, Mon. faune éocénique Alabama, p. 250, Pl. XLIII, figs. 16-20.

Clypeaster rogersi De Loriol, 1890, Soc. phys. hist. nat. de Geneva Mém., vol. suppl. du centenaire, p. 99.

Scutella rogersi Clark, 1891, Johns Hopkins Uniy. Circ., vol. 10, No. 87, p. 77.

Echinanthus rogersi Gregory, 1891 (discussion), Geol. Soc. America Bull., vol. 3, p. 105. :

Mortonia rogersi Gregory, 1891 (tabulation), Geol. Soc. America Bull., vol. 3, p. 105. This was evidently a lapsus calami.

Scutella rogersi Boyle, 1893, U. S. Geol. Survey Bull. 102, p. 263.

EOCENE ECHINODERMATA. 137

Mortonia rogersi Dana, 1895, Manual of geology, 4th ed., p. 898, fig. 1491.

Clypeaster douvillei Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 682, Pl. XXII, figs. la-c.; p. 698.
Clypeaster jonesi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

Clypeaster turgidus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.

Determinative characters.—Test medium in size; subpentagonal to suboval, anterior end
rounded, posterior end truncated at the corners and centrally, longer than broad, usually
widest opposite ends of anterior petals; much depressed, upper surface rising more or less gradu-
ally from the rather thick margin to the low central apex, sometimes regularly arched or of
convex outline from margin to margin, sometimes subconical centrally; under surface flat around
the margin, concave centrally. Ambulacral petals large, tumid, elliptical, anterior pair shorter
than the rest which are about equal, all extending from about one-half to two-thirds the way to
the margin, wide open at the ends; poriferous zones wide, outer rows of pores depressed below
the general surface. Apical system central; genital pores five. Peristome medium in size,
central; ambulacral furrows simple, straight, well defined, reaching the margin. Periproct
small, inframarginal; situated from one-fifth to one-sixth the distance from the margin to the
peristome.

Dimensions.—Specimen A: Length 70 millimeters; width 63.5 millimeters; height 16.5
millimeters. Specimen B: Length 45 millimeters; width 43.5 millimeters; height 17 millimeters.

Description.—The species, to judge from the number of specimens reported, is the most
abundant of American clypeasters, being rather common in the Jackson and Vicksburg forma-
tions of Mississippi, Alabama, and Georgia. It is also one of the first species of echinoids dis-
covered in American Cenozoic deposits, haying been figured and described by Morton in 1834.
This species has been frequently confused with Mortonella quinquefaria (Say), partly because of a
resemblance in general appearance, but more because of certain mistakes in identification made
by L. Agassiz and by Desor. In 1841 Agassiz described and figured a specimen of Mortonella quin-
quefaria (Say) under the impression that he was dealing with one of Clypeaster rogersi (Morton).
In 1858 Desor made matters worse by describing Say’s form and founding upon it the new genus
Mortonia; but, instead of figuring it, citing as a good illustration Morton’s figure of C. rogersi.
As a result of these mistakes many specimens were found mislabelled in the various collections
studied and the synonymy of the two forms was found to be in a tangle requiring considerable
labor to unravel. MM. quinquefaria can easily be separated from the present species by its more
circular outline and discoidal form, less tumid petals, less concave under surface, branching
ambulacral furrows, and the more distant position of its periproct from the posterior border.
About ten years after Morton’s description of the present species was published, Lyell collected
in Georgia some specimens which were described and figured by Forbes and given the new spe-
cific name of Scutella jonesii, but a careful study of the figures and descriptions, aided by an
extensive series of specimens, although without the types, fails to reveal any essential differences
between the two forms. Conrad’s Mortonia turgida, which he appears to have also called
Mortonia tumida and still later Clypeaster tumidus was probably a specimen of C. rogersi, which
was tumid centrally.

The test of Clypeaster rogersi is of medium size, ranging from about 13 to about 3 inches in
length. In marginal outline it is somewhat variable, being subpentagonal in most specimens
though nearly oval in others; the anterior end is usually rounded; the posterior end is truncated
centrally, with corners either truncated or rounded; the sides are either straight, slightly convex,
or slightly concave; the longitudinal diameter exceeds the transverse; most specimens are
broadest opposite ends of anterior petals, but some are broadest centrally. The whole form is
greatly depressed, the upper surface either rising gradually and gently from the margin to the
apex and showing an almost regularly arched or convex outline from margin to margin when
viewed from the side or end, or rising centrally in a subconical mound involving the petaloidal
area; apex central, low, its height rarely exceeding one-fourth the width of the test; margin
thick and rounded anteriorly, becoming thinner and more wedge-shaped posteriorly. The
under surface flat, or nearly so, around a wide marginal area, concave centrally; the concavity
increasing more rapidly as the peristome is approached, the depth of the concavity being about
one-third the height of the test.

138 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacral areas are rather wide, both at the margin and across the middle of the
petals, in both cases wider than the interambulacral areas; dorsal portions petaloid. The
petals are rather large, elliptical to subspatulate in form, anterior pair slightly shorter than the
rest which are about equal in length, all extending from about one-half to two-thirds the way
to the margin, moderately to widely open at the ends. The poriferous zones are wide, inner
rows of pores elevated, nearly straight, either nearly parallel or slightly diverging and consist
of round openings; outer row of pores depressed below the general surface, curving and com-
posed of slitlike openings; pairs of pores conjugated; interporiferous areas varying in width
from only slightly wider than poriferous zones to nearly twice as wide, elevated so that the
petals are somewhat tumid.

The interambulacral areas are wide opposite the ends of the petals, rather narrow at the
margin. The whole surface of the test, including even the ridges between the pairs of pores of
the poriferous zones, is covered with very small, uniform imperforate tubercles, set in rather
deep scorbicules. The tubercles are slightly larger on the under surface.

The apical system is central, coincident with the apex. There are five genital pores at the
tips of the points of the almost star-shaped madreporite; and five small ocular plates extending
between the points of the star, each perforated by a minute pore. The apical system, together
with a very small area immediately surrounding it and involving the inner ends of the petals, is
elevated slightly above the rest of the test.

The peristome is medium in size, central, subcircular to subpentagonal, and situated at the
deepest portion of the concavity on the under surface. The ambulacral furrows are simple,
straight, well defined, extending from peristome to margin; on well-preserved specimens they can
be seen to continue as a faint line over the margin and along the middle of the ambulacral petals
nearly to the apical system.

The periproct is small, subcircular, inframarginal, from one-fourth to one-sixth of the dis-
tance from the margin to the peristome.

Related forms.—Clypeaster rogersi is not closely-related~to~any-\meriean—species, but
resembles a number of foreign forms in general appearance, and is very similar to sevéral of them.
C. biarritzensis Cotteau, from the upper Eocene of France, greatly resembles the present species,
but its ambulacral petals are more nearly equal (or, if there is any difference, the odd petal is the
longest), its interporiferous areas are relatively wider, and its poriferous zones relatively nar-
rower, more divergent, and therefore more widely apart at the ends. C. simplex Duncan and
Sladen, from the Oligocene of Western Sind, India, also closely resembles C. rogersi, but differs
in having petals which are longer and tend to close more nearly at the ends. Two species from
the Miocene of Cuba, C. concavus Cotteau and C. cotteau Egozcue, resemble C. rogersi in certain
points; but both are relatively higher than the present species and C- cotteawi has straighter and
more widely divergent poriferous zones. Michelin? stated that he regarded C. jonesii Forbes
(which is here regarded as asynonym of (. rogersi) as the young of C. ambigenus De Blainville, a
recent West Indian species. The writer can not agree with this view, as C. ambigenus is con-
siderably higher, less concave on the under surface, and has more elliptical interporiferous areas
due to the more curving character of the inner rows of pores of the poriferous zones. Stefanini’s
C. douvillei appears to be a C. rogersi with relatively thin margin and subconical upper surface,
such as the writer has found to grade into the more typical representatives of the species.

Localities—Near Shubuta, 5 miles west of Shubuta, Vicksburg, and Jackson, Miss.; St.
Stephens Bluff, 9 miles north of St. Stephens, 5 miles south of Claiborne, Gainestown, near
Rescueyille, Choctaw County, near Claiborne, and Clarksville, Ala.; Hawkinsville, and 5 miles
southwest of Hawkinsville, Ga.

Geologic horizon.—Jacksou formation, upper Eocene; Vicksburg formation, lower Oligocene.

Collections.—U. 8. National Museum (137801, A and 155377, B); Geological Survey of
Alabama; Boston Society of Natural History; Academy of Natural Sciences of Philadelphia;
Wagner Free Institute of Science.

1 Monographie des Clypéastres fossiles: Soc. géol. France Mém., 2d ser., vol. 7, p. 113, 1861.

EOCENE ECHINODERMATA. 139

Genus ECHINANTHUS Leske.
ECHINANTHUS GEORGIENSIS Twitchell, n. sp.
Plate LXV, figure la-d.

Determinative characters.—Test subpentagonal, broadest posteriorly, anterior end straight,
posterior end pointed, notched and rostrate, upper surface depressed, convex, with a longi-
tudinal keel along the posteromedian area; under surface concave around the peristome; apex
forward of the center. Ambulacral areas narrow; dorsal portions petaloid, petals narrow and
rather short. Apical system small, anteriorly excentric. Peristome subpentagonal, transversely
elongate, anteriorly excentric, with well-developed floscelle. Periproct small, oval, marginal, at
the top of a vertical sulcus which notches the posterior end, and beneath a slightly overhanging
projection of the keel.

Dimensions.—Length 42 millimeters; width 41 millimeters; height 18 millimeters.

Description.—The species, the first of the genus Echinanthus to be reported from the United
States, is very rare, only a single specimen having been found up to the present time. It is of
especial interest because it is one of the earliest of the Cenozoic echinoids, the type having been
found in the Midway formation of Georgia. The test is subpentagonal in marginal outline,
broadest back of the center, from which it narrows both anteriorly to the straight anterior edge
and posteriorly to the pointed posterior end; margin angular all around, rostrate posteriorly,
with a notch at the posterior end which can be seen from both above and below. The upper
surface is depressed, convex, declining rather steeply on all sides from the apex, with a rounded
longitudinal keel along the posteromedian area, on both sides of which the surface is obliquely
flattened; under surface concave around the peristome. The apex is slightly forward of the
center.

The ambulacral areas are narrow throughout their whole length; dorsal portions petaloid;
petals narrow, rather short, partly closing, the posterior pair slightly longer than the anterior
pair which are longer than the odd petal. The poriferous zones are narrow, outer pores oval,
inner ones round, pairs of pores conjugate.

The apical system is small, excentric anteriorly, slightly more so than the apex. There are
four genital pores, of which the anterior pair are nearer together than the posterior; and there
appear to be five very small perforated radiai plates. The madreporite is very small and flush
with the surface.

The surface of the test is closely set with very small, apparently imperforate tubercles with
deep scrobicules. The tubercles are slightly larger on the under surface except along a rather
narrow nearly bare median band back of the peristome.

The peristome is excentric anteriorly, beneath the apical system, subpentagonal, trans-
versely elongate, with a well-developed floscelle.

The periproct is small, oval, the greater diameter being vertical; marginal, or slightly supra-
marginal, beneath a slightly overhanging projection of the keel, at the top of a vertical sulcus
which notches the posterior end of the test.

Related forms.—Echinanthus georgiensis is quite distinct from all other American echinoids,
the notched posterior end and the details of the periproct affording a ready means of separation
from all forms which in any way resemble it. Among foreign forms it resembles Echinanthus
subcarinatus Goldfuss from the Oligocene of Germany but has a less regularly oval outline and a
less pronounced posterior rostration.

Locality.—Five miles south of Ellaville, Ga.

Geologic horizon.—Midway formation, lower Eocene.

Collection.—U. S. National Museum (1656836b).

140 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Order ATELOSTOMATA.
Suborder ASTERNATA.
Family CASSIDULID.

Genus CASSIDULUS Lamarck.
CassIDULUS CALIFoRNICUS F. M. Anderson.
Plate LXV, figure 2a-b.
Cassidulus californicus F. M. Anderson, 1905, California Acad. Sci. Proc., 3d ser., Geology, vol. 2, No. 2, p. 194, Pl.

XIII, figs. 6, 7.

Cassidulus californicus Arnold, 1909, U. 8. Geol. Survey Bull. 396, p. 18, 112, Pl. IV, figs. 1, la.
~ Cassidulus californicus Arnold and R. Anderson, 1910, U. S. Geol. Survey Bull. 398, pp. 70, 284, Pl. XXVI, figs. 1, la. :
Cassidulus californicus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 696. i

Description.—As the writer has not been able to obtain possession of any specimens of this
species the description of Anderson is given verbatim:

Test small, elliptical, robust and often somewhat globular; lower surface flattened, or concave, upper surface convex;
mouth not central, round, and occupying a position three-fifths of the distance from the anal margin; anal pore terminal;
apical star nearly symmetrical, central, on dorsal surface; tuberculation distinct, the tubercles lying within rounded
pits. There isa tendency to form shoulder-like expansions on the periphery behind the position of the mouth.

Anderson does not mention a floscelle nor do his figures show one, but the figured specimen
of Arnold shows a floscelle distinctly. * Arnold’s figures also show a test with a suboblong margi-
nal outline and a supramarginal periproct, apparently transverse, beneath an overhanging
expansion of the test. Arnold’s form, here refigured, was 21 millimeters long.

Locality.—F our miles west-northwest of Coalinga, Cal.

Geologic horizon.—Tejon formation, upper Kocene.

Collections. —California Academy of Natural Sciences; U.S. National Museum (165664).

CassipuLus (RuyNcHOPYGUS?) HoLMEsSI Twitchell, n. sp.
Plate LXV, figures 3a-d.

Determinative characters —Test small, broadly oval, slightly truncated at the posterior end;
upper surface convex, sides and ends rounded and inflated; under surface concave around the
peristome. Ambulacral areas narrow, petaloid; petals nearly equal, partly open. Apex cen-
tral; apical system excentric anteriorly. Peristome excentric anteriorly, pentagonal, longitu-
dinally elongate, with a floscelle. Periproct elliptical, transverse, supramarginal; located in a
rather deep, oval indentation whose edges are almost flush with the posterior surface of the test.

Dimensions.—Length 25 millimeters; width 22.5 millimeters; height 14 millimeters.

Description.—Only a single specimen of this interesting species is known to the writer. It
was found in the F. S. Holmes collection, now owned by the American Museum of Natural
History, and asit was probably collected by Holmes is named in his honor. The test is small,
broadly oval, being but slightly longer than it is broad, slightly truncated at the posterior end.
The upper surface is regularly convex, somewhat elevated, sides and ends sloping nearly uni-
formly to the rounded and inflated margin; under surface tumid around the margin, concave
around the peristome; apex central.

The ambulacral areas are rather narrow, dorsal portions petaloid; petals nearly equal in
length, the posterior pair being but slightly longer than the others, nearly closing at the ends.
The poriferous zones are rather broad, outer row of pores oval, inner row round, pairs of pores
conjugate. :

The surface of the test is closely set with small tubercles in deep scrobicules, which are
larger on the under surface except along a eribriform median band.

The apical system is excentric anteriorly. There are four genital pores of which the ante-
rior pair are nearer together than the posterior. No further details can be made out on the single
specimen known.

EOCENE ECHINODERMATA, 141

The peristome is excentric anteriorly, immediately beneath the apical system, pentagonal,
longitudinally elongate, with a floscelle.

The periproct is elliptical, transverse, supramarginal, located in a rather deep, oval indenta-
tion at the top of the slight posterior truncation. The edges of the indentation are almost even
with the posterior margin. Below the periproct a vaguely defined, broad, shallow groove extends
downward across the margin.

Related forms.—Cassidulus holmesi is not closely allied to any American form. Its broadly
oval and uniformly convex form, nearly equal ambulacral petals, and the details of its periproct
and peristome readily distinguish it. It does not appear to be closely related to any foreign
form.

Locality.—Santee River (7), S. C.

Geologic horizon.—Probably in the McBean formation of Claiborne group, middle Hocene.
The matrix is a fine-grained greensand such as is known to occur on Santee River.

Collection.—American Museum of Natural History.

CassipuLus (RHYNCHOPYGUS) LYELLI (Conrad).

Plate LXV, figures 4a-d.

Nucleolites lyelli Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 40, fig. 14.
Cassidulus lyelli Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.

Pygorhynchus lyelli Cotteau, 1888, Paléontologie francaise, Echinides éocénes, vol. 1, p. 550.
Nucleolites lyelli Boyle, 1893, U. S. Geol. Survey Bull. 102, p. 200.

Pygorhynchus lyelli Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 696.

Determinative characters.—Test low, oval in marginal outline, truncated at the posterior end;
upper surface convex, depressed; under surface slightly concave around the peristome; apex
slightly excentric posteriorly. Ambulacral areas narrow, dorsal portions petaloid; petals long,
elliptical. Poriferous zones narrow; pores subequal; interporiferous areas rather wide. Apical
system excentric anteriorly. Peristome excentric anteriorly, beneath the apical system, sub-
pentagonal to subtriangular, with a floscelle. Periproct suboblong to dumbbell shaped, trans-
versely elongate, supramarginal, nearly flush with the truncated posterior face of the test; with
an overhanging rostrum.

Dimensions.—Length 33 millimeters; width 28 millimeters; height 15 millimeters.

Deseription.—The present whereabouts of the type of Conrad’s Cassidulus lyelli is unknown;
but as the present species answers so well to Conrad’s description and drawings and as it came
from about the same locality, it is thought highly probable that it is the same. However, as
only a single somewhat imperfect specimen is known, further collecting may show that it is not
Conrad’s form, in which case the present species will have to receive a new name. The test is
regularly oval or subelliptical in marginal outline, vertically truncated at the posterior end. The
upper surface is low, almost uniformly convex, depressed, shghtly more elevated posteriorly
than anteriorly; under surface slightly convex posteriorly, faintly concave around the peristome.
The apex is slightly excentric posteriorly.

The ambulacral areas are narrow, dorsal portions petaloid, petals long, symmetrically
elliptical, somewhat open at the ends, the posterior pair longer than the others, which are nearly
equal in length. The poriferous zones are narrow, similar; pores subequal in size, outer row
oval, inner row round, pairs of pores conjugate; interporiferous areas relatively rather wide.

The surface of the test is closely set with small scrobiculate tubercles, which are larger on
the under surface. The under surface is poorly preserved on the single specimen obtained;
but there appears to have been a median band back of the peristome which was somewhat
smoother than the adjacent areas and was more or less pitted.

The apical system is excentric anteriorly, being about three-eighths the length of the test
from the anterior end. The details can not be made‘out, beyond the fact tiiat there are four
genital pores of which the anterior pair are nearer together than the posterior.

The peristome is excentric anteriorly, immediately beneath the apical system. It is
poorly preserved; but there is enough to show that it is subpentagonal, though approaching a
subtriangular form, and surrounded by a somewhat inconspicuous floscelle.

39800°—15——10

142 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The periproct is subelliptical to suboblong, considerably elongated transversely, supra-
marginal, at the top of and nearly flush with the vertically truncated posterior surface of the
test. The rounded central part of the upper edge extends downward so as to break the ellipti-
cal contour of the periproct, and projects slightly beyond the periproct so as to slightly overhang
the vaguely defined broad and shallow groove which extends below the periproct across the
posterior margin.

Related forms.—Cassidulus lyelli is quite distinct from all other representatives of the
genus from American strata. Its transversely suboblong periproct and its low regularly oval
form readily permit of its identification. It does not appear to be closely related to any foreign
form.

Locality—tIn Baker County, Ga.

Geologic horizon.—Jackson formation, upper Eocene.

Collection.—Boston Society of Natural History (1552a). .

CasstpuLus (RHYNCHOPYGUS) RAVENELI Twitchell, n. sp.

Plate LXV, figures 5a-d; Plate LX VI, figures la-c, 2a—b.

Pygorhynchus crucifer Ravenel, 1848, Echinidee, recent and fossil, of South Carolina, p. 4, Pl. II, figs. 9, 10.

Pygorhynchus crucifer Ravenel, 1850, Cat. recent and fossil Echinide of South Carolina: Am. Assoc. Ady. Sci. Proc.,
vol. 3, p. 160.

Ravenelia crucifer McCrady, 1859, Elliott Soc. Nat. Hist. Charleston Proc., vol. 1, pp. 282, 283,.no figure.

Pygorhynchus crucifer Agassiz, 1883, Mus. Comp. Zool. Mem., vol. 10, No. 1, p. 91.

non Nucleolites crucifer Morton, 1834, Synopsis organic remains Cretaceous, p. 75, Pl. III, fig. 15.

non Trematopygus crucifer Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 76.

non Trematopygus crucifer Clark, 1893, U. 8. Geol. Survey Bull. 97, p. 63.

Determinative characters—Test hemiellipsoidal, elliptical in marginal outline, truncated
at posterior end; upper surface considerably depressed, convex, declining more gently to the
ends than to the sides; under surface slightly concave longitudinally. Ambulacra petaloid,
the posterior petals longer than the others and bending outward toward their ends. On the
under side there is a wide, longitudinal, median band, where the tubercles are replaced by a
more or less pitted surface. Apex central; apical system excentric anteriorly. Peristome
pentagonal, excentric anteriorly, with a well-defined floscelle. Periproct supramarginal,
rather large, elliptical, transverse, concealed beneath an overhanging rostrum at the head of a
short, broad sulcus.

Dimensions.—Specimen A (type): Length 40 millimeters; width 29 millimeters; height 14
millimeters. Specimen C: Length 55 millimeters. Largest specimen seen: Length 55 milli-
meters; width 39 millimeters; height 18 millimeters.

Description —Dr. Edmund Ravenel, of Grove, S. C., m 1848, in a pamphlet of which
but a few copies were printed, gave some good figures of a form which is evidently the same
as the one here described. He gave no description and did not regard the form as new; but
said it was the same as Nucleolites crucifer Morton and placed it in the genus Pygorhynchus.
Ravenel was undoubtedly mistaken in regarding his form as the same as that of Morton, for
there is hardly more than a superficial resemblance between them. W. B. Clark assigns Morton’s
form to the genus Trematopygus, whereas the form which Ravenel figured and which is here
described for the first time is a Cassidulus of the Rhynchopygus type. However, in view of
Ravenel having been the discoverer of the form and in recognition of his interest im and additions
to the knowledge of the fossil Echinoidea of South Carolina this interesting species is named
after him.

The test of this species is hemiellipsoidal in form, regularly elliptical in marginal outline,
and truncated and slightly indented at the posterior end. The upper surface is low, depressed,
and rather uniformly convex, though more abruptly so transversely than longitudinally; under
surface slightly concave along the longitudinal median area, the concave portion being limited
along the sides by the somewhat inferiorly projecting side edges. The apex is central.

1The Library of Congress at Washington possesses the copy which was studied by the writer.

EOCENE ECHINODERMATA. 143

The ambulacral areas are petaloid, the petals rather long and narrow, converging toward
their extremities, where they remain partly open; the posterior pair longer than the rest and
bending outwardly near their extremities; the odd petal shorter than the posterior but slightly
longer than the anterior pair. The poriferous zones are rather narrow, but slightly more than
half the width of the narrow interporiferous areas; outer row of pores slitlike, inner row round;
pairs of pores conjugated by narrow grooves separated by low, easily effaced ridges.

The interambulacral areas are broad; the posterior area slightly inflated from the apex to
the periproct, where it projects as an overhanging rostrum. The tubercles on the upper sides
of the test are numerous, uniformly small, close together, and with deep scrobicules; the inter-
vening spaces being covered with still smaller granulations. On the under side the tubercles are
larger, except along a rather wide, longitudinal, median band, which is free from tubercles but
dotted with numerous pits.

The apical system is excentric anteriorly, compact, and consists of four basal plates per-
forated by large pores, the two anterior pores being slightly nearer together than the posterior;
five small radial plates, each perforated by a mimute pore; and a large madreporite, which occupies
the center of the system.

The peristome is of medium size, pentagonal, excentric anteriorly, directly beneath the
- apical system, with a well-defined floscelle. The floscelle is composed of five prominent rounded
bourrelets with granulated surfaces alternating with five large well-developed phyllodes. In
addition to outer rowsof pores each phyllode has two inner rows ending in two rather large pores,
which are located just between adjacent bourrelets.

_The periproct is rather large, elliptical, transversely elongate, supramarginal, and con-
cealed beneath an overhanging rostrum at the head of a broad and rather shallow sulcus, which
extends beyond the rostrum to the truncated posterior margin of the test.

Related forms.— Cassidulus raveneli from its size, shape, and details of structure is readily
separated from the other representatives of the genus occurring in the American and European
Cenozoic deposits. In several features it resembles Rhynchopygus calderi d’Archiac and Haime
from the Tertiary deposits of India, but it is more depressed and has a more regularly elliptical
marginal outline. Inaless degree it resembles Eurhodia morrisii V Archiac and Haime, also from
the Tertiary deposits of India, but it is more depressed and lacks the very elongated peristome so
characteristic of the Indian form. The nearest American form is Cassidulus depressus, from
which it is readily distinguished by its greater size and the details of its periproct.

Localities —South Carolina (Ravenel); Santee Canal (figured specimens), S. C.; Rocky
Point and Wilmington, N. C.

Geologic horizon.—In North Carolina in the Castle Hayne limestone, upper Eocene or
Oligocene. In South Carolina probably in the Cooper marl (upper Eocene) or the upper part
of the McBean formation (middle Eocene).

Collections —American Museum of Natural History (A, B, and C); U. S. National
Museum; Johns Hopkins University.

CasstpuLus (RHYNCHOPYGUS ?) PATELLIFORMIS (Bouvé).

Plate LX VI, figures 3 a-d.

Catopygus patelliformis Bouvé, 1851, Boston Soc. Nat. Hist. Proc., vol. 4, p. 2, text figures.
Cassidulus patelliformis Desor, 1858, Synopsis des échinides fossiles, p. 290.

Cassidulus patelliformis Dujardin and Hupé, 1862, Hist. nat. zoophytes échinodermes, p. 583.
Cassidulus patelliformis Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.

Cassidulus patelliformis Conrad, 1866, Smithsonian Misc. Coll., vol. 7, p. 22.

Cassidulus patelliformis Cotteau, 1888, Paléontologie francaise, Echinides éocénes, vol. 1, p. 421.
Cassidulus patelliformis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 700.

Determinative characters.—Test elliptical, narrowing and rather pointed posteriorly; upper
surface somewhat elevated, convex, elongate-subconical; under surface flat, meeting the upper
surface in an angular margin; apex slightly forward of the center. Ambulacral areas narrow,
petaloid; petals rather long, the anterior pair shorter than the posterior pair and odd petal

144 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

which are nearly equal in length, closing at the ends. Peristome apparently slightly excentric
anteriorly. Periproct small, elliptical, transverse, supramarginal, in a shallow indentation
close to the posterior end of the test.

Dimensions.—Length 32 millimeters; width 21 millimeters; height 15 millimeters.

Description.—This species was first reported in 1851 by T. T. Bouvé of Boston. The doubt
in regard to the generic position of Bouvé’s form, which Desor recognized as existing because
of a lack of definite knowledge in regard to the inferior surface, is partly resolved by an exami-
nation of the type, which though not showing a floscelle does show a cribriform median area
on the under surface. A valuable corroboration of this evidence is found in the fact that one
specimen of Cassidulus depressus, the form most nearly related to the present species, shows:
a well-defined floscelle. The test of this species is elliptical 4 in marginal outline, narrowing
noticeably toward the posterior end. The upper surface is somewhat clerated. convex, clone
subconical, sloping steeply to the margin, slightly less so posteriorly than on the sales, and
anteriorly; under surface flat, meeting the sides at the margin in an acute angle; apex slightly
forward of the center. The general appearance of the form, as the name given by Bouyé
implies, is much like that of a limpet shell such as those of the genus Patella.

The ambulacral areas are narrow, narrower at the ambitus than in the petaloid region;
dorsal portions petaloid, the petals rather long, the anterior pair shorter than the posterior
pair and odd petal, which are nearly equal in length; petals closing at their extremities. The
details of the ambulacra and apical system are not discernible on the specimen.

The peristome is apparently slightly eccentric anteriorly; details can not be made out.
The periproct is small, elliptical, transverse, supramarginal; located in a small, shallow, trans-
verse indentation only shghtly above the margin and very close to the rather pointed, truncated,
posterior end of the test.

The surface of the test is covered with numerous small tubercles, with scrobicules, larger
on the under surface except along a rather broad median area back of the peristome where the
surface is free from tubercles and more or less cribriform. .

Related forms.—No other species of Cassidulus reported from the United States bears any
close resemblance to Cassidulus patelliformis. It is closely related to Cassidulus depressus but
can easily be distinguished by its greater size, more elevated and elongated subconical upper
surface, more steeply sloping posterior face, and lower placed periproct.

Locality.— Georgia, probably Baker County.

Geographic horizon.—Probably upper Eocene. May be lower Oligocene.

Collection.—Boston Society of Natural History (1558).

CassIDULUS (RHYNCHOPYGUS) DEPRESSUS Twitchell, n. sp.
Plate LXVI, figures 42-e, 5a—b.

Determinative characters—Test very small, subelliptical, upper surface much depressed,
convex, declining gently on the sides, the posterior end sloping more steeply than the anterior;
undersurface slightly concave. Apex central; apical system excentric anteriorly. Peristome
small, pentagonal, slightly elongate longitudmally, anteriorly excentric, with a well-defined
floscelle. Between the peristome and the posterior border there extends a wide, elliptical,
erlbriform area. Periproct small, elliptical, transverse, situated rather high above the posterior
margin, in a shallow indentation,

Dimensions. sien A (ame) Length 16 millimeters; wal 12 millimeters; height
7 millimeters.

Description.—This small Cassidulus, one of the smallest representatives of the genus
occurring in American deposits, has a test which is subelliptical in marginal outline. The
upper surface is much depressed, longitudinally convex, declining gently on the sides. ‘The
posterior median area, between the apical system and the periproct remains at nearly the
same elevation from which the surface slopes steeply to the posterior margin and less steeply
to the anterior. The undersurface is nearly flat, or slightly concave longitudinally, meeting
the sides at the margin in a somewhat acute angle. The apex is central or subcentral.

EOCENE ECHINODERMATA. 145

The ambulacral areas are obscure on the specimens studied; but are apparently narrow
with petaloid dorsal portions. The narrow poriferous zones show an outer row of slitlike
pores and an inner row of round pores. The other details can not be made out. The apical
system is excentric anteriorly; its details are not discernible.

The peristome is small, pentagonal, slightly elongate longitudinally, anteriorly excentric,
beneath the apical system, with a well-defined floscelle having prominent bourrelets and rather
extensive rounded phyllodes.

The periproct is small, elliptical, transverse, situated rather high above the posterior
margin in an indentation in the test,

The surface of the test is covered with numerous small tubercles, with scrobicules, larger
on the under surface. Between the peristome and the posterior border there extends a wide
elliptical, cribriform area.

Related forms.—This form is most closely related to Cassidulus patelliformis (Bouvé)
from which it is readily distinguished by its smaller size, more depressed form, the higher
position of its periproct, and the greater relative elevation of the upper surface between the
periproct and the apical system. It also resembles Cassidulus raveneli but is very much smaller,
and its periproct has a less conspicuous overhanging rostrum in a shallower depression. In
several respects it resembles Rhynchopygus pygmzus Duncan and Sladen from the Tertiary of
India, but it is more depressed and much narrower posteriorly.

Locality —Baker County, Ga.

Geologic horizon.—Probably upper Eocene. May be lower Oligocene.

Collection.—Boston Society of Natural History (1557a, A; 1557b, B).

CassIDULUS (PYGORHYNCHUS) CONRADI Conrad.
Plate LX VII, figures la-f.

Catopygus conradi Couper MSS., fid. Conrad.
Catopygus conradi Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 39, Pl. I, fig. 9.
Cassidulus conradi Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75. RAR
Cassidulus conradi Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 22. : i :
Catopygus conradi Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 90.
Cassidulus conradi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 700.

Determinative characters.—Test ovate in marginal outline, broad anteriorly, narrowing
abruptly posteriorly; sides and anterior end somewhat flattened, posterior end truncated;
upper surface convex, depressed, flattened on top; under surface flattened, slightly concave
around the peristome; apex usually forward of the center. Ambulacral areas narrow. Apical
system very excentric anteriorly. Peristome excentric anteriorly, less so than the apical system,
pentagonal, transversely elongate, with a floscelle. Periproct elliptical, transverse, supra-
marginal; beneath an overhanging expansion of the test, whose edge is even with the posterior
margin.

Dimensions.—Length 41 millimeters; width 35 millimeters; height 23 millimeters.

Description.—This species was first figured in 1850 by Conrad, who also gave a good deserip-
tion of the form. He, however, credits the species to a manuscript description by J. Hamilton
_ Couper and says that the name given was adopted at the particular request of Mr. Couper.
The test is ovate in marginal outline, broad anteriorly, narrowing abruptly posteriorly; margin
somewhat flattened anteriorly, more so on the sides which are nearly vertical at the ambitus
but round over the edges to the upper and lower surfaces, obliquely truncated posteriorly and
truncated vertically at the posterior end. The upper surface is convex, depressed, flattened
on top, and in the form of a low, rounded ridge above the periproct; undersurface flattened,
slightly concave around the peristome and slightly convex posteriorly. The lower edge at the
posterior end is somewhat prominent, angular and slightly rostrate. The apex is usually
forward of the center, when it is coincident with the apical system; but even then it is only
slightly higher than the surface of the posterior interambulacrum, and in some forms the upper
surface is so depressed anteriorly as to make the apex excentric posteriorly.

146 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The ambulacral areas are narrow, dorsal portions petaloid; petals long, narrow, and open
at their ends, the posterior pair bemg longer than the others which arc nearly equal in length.
The poriferous zones are narrow, the adjacent zones of the anterior and posterior paired petals
being slightly broader and straighter than the others; pores small, outer row slitlike, inner
row round, pairs of pores conjugate.

The apical system is very excentric anteriorly, being located less than a third of the length
of the test from the anterior end. There are four genital pores, of which the anterior pair
are nearer together than the posterior; and there are five small perforated radial plates. These
are the only details that can be made out on the specimens.

The surface of the test is closely set with very small imperforate tubercles with deep
scrobicules. The tubercles are slightly larger on the under surface except along a narrow
median band back of the peristome, which is free from tubercles, nearly smooth and dotted with
numerous very small pits.

The peristome is excentrice anteriorly, less so than the apical system, pentagonal, trans-
versely elongate, with a well-defined floscelle.

The periproct is rather large, elliptical, transverse, supramarginal, at the top of the pos-
terior truncation; beneath a rounded, transverse, somewhat protruding expansion of the test
whose edge is about even with the truncated posterior margin.

Related forms.—Cassidulus conradi is readily distinguished from the other representatives
of the genus from American strata. It is most nearly related to Cassidulus carolinensis, but
can be separated by its more excentric apical system and more transverse peristome and by
being narrower posteriorly and less concave around the peristome. Its nearest European ally
appears to be Pygorhynchus maveri de Loriol from the Tertiary of Switzerland, but the latter
has both its apical system and peristome less excentric anteriorly and does not have its peristome
transversely elongated. C. conradi also resembles. Pygorhynchus grignonensis (Defrance)
Agassiz from the Eocene of France, but is narrower posteriorly and has its apical system less
excentric anteriorly.

Localities—Palmyra, Lee County, Ga. (Conrad); Baker County, Ga.

Geologic horizon.—Upper Eocene or lower Oligocene or both. Conrad gave the matrix of
the form as white limestone.

Collections. —Academy of Natural Sciences of Philadelphia (1078); Boston Society of Natural
History.

CassipuLUS (PYGORHYNCHUS) CAROLINENSIS Twitchell, n. sp.

Plate LXYVII, figures 2a-g.

Determinative characters.—Test thin walled, oval in marginal outline, posterior end trun-
cated; sides and anterior end rounded; upper surface convex, depressed, slightly more elevated
posteriorly than anteriorly and with a rather prominent low, rounded ridge above the periproct;
under surface flat, concave around the peristome; apex central or slightly excentric posteriorly.
Ambulacral areas narrow. A narrow granulated, median band back of the peristome. Apical
system, excentric anteriorly; madreporite slightly tumid. Peristome excentric anteriorly,
directly beneath apical system, pentagonal, with a floscelle. Periproct elliptical, transverse,
supramarginal beneath an overhanging expansion of the test, whose edge is even with the
posterior margin.

Dimensions.—Length 36 millimeters; width 32 millimeters; height 18 millimeters. This
specimen is about a fourth larger than the average.

Description.—This species occurs in large numbers at several localities in North Carolina,
notably in association with Echinolampas appendiculatus. The test is thin walled, regularly
oval in marginal outline, the posterior end vertically truncated. The upper surface is uniformly
convex, depressed, sides and anterior end rounded, slightly more elevated posteriorly than
anteriorly and in the form of a low rounded ridge above the periproct; under surface flat, tumid
near the margin, concave around the peristome. The apex is central, or slightly excentric
posteriorly.

EOCENE ECHINODERMATA. 147

The ambulacral areas are narrow, dorsal portions petaloid; the petals long, rather narrow,
nearly closing, the posterior pair slightly longer than the others which are nearly equal in length.
The poriferous zones are rather narrow, strani depressed, outer pores oblong, inner ones round,
pairs of pores conjugate.

The surface of the test, including the interporiferous areas and the ridges between the pairs
of pores, is closely set with small imperforate tubercles set in deep scrobicules. Between the
tubercles are minute granules. The tubercles increase in size on the under surface except along
a narrow band back of the peristome, which is somewhat smooth but dotted with numerous
eranulations.

The apical system is excentric anteriorly. There are four genital pores, the anterior pair
being nearer together than the posterior; and five perforated radial plates. The madreporite is
large, oval and faintly tumid, as are the adjacent portions of the interambulacral areas.

The peristome is somewhat large, pentagonal, excentric anteriorly, directly beneath the
apical system, surrounded by a floscelle of which the bourrelets are rather prominent, granu-
lated, and together form a nearly circular ring around the peristome.

The periproct is elliptical, transverse, supramarginal, at the top of the posterior truncation;
beneath a rounded, transverse, somewhat protruding expansion of the test, whose edge is just
even with the truncated posterior margin.

Related forms.—Cassidulus carolinensis is closely related to C. conradi and resembles it in a
number of features, notably in the detaus of the periproct; but it is to be separated by its less
excentric apical system, by its less transverse peristome with the subcircular ring of bourrelets,
by being broader, more rounded and less rostrate posteriorly, and by having a more marked
concavity around its peristome. (. carolinensis also resembles C. georgiensis but is to be distin-
guished by the concavity around its peristome, its less obtuse and less angular posterior margin,
and its lower and less oblique posterior truncation. Among European forms C. carolinensis
greatly resembles Pygorhynchus maveri De Loriol from the Tertiary of Switzerland (more so than
does QC. conradi), but differs in having its periproct higher up on the posterior surface, and in the
failure of the expansion of the test over the periproct to protrude noticeably beyond the posterior
margin. In a number of features C. carolinensis is similar to Pygorhynchus grignonensis
(Defrance) Agassiz from the Eocene of France, but it can be separated by its more depressed
form and the higher relative position of its periproct.

Localities. —Smith Creek (type), Rocky Point, and Wilmington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Oollections.—Johns Hopkins University (T 2004); U.S. N National Museum.

CASSIDULUS AMYGDALA Desor.

Cassidulus amygdala Desor, 1858, Synopsis des échinides fossiles, p- Ixy.
Cassidulus amygdala Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 22
Cassidulus amygdala Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 22

This is a Swiss species described on page 290 of Desor’s Synopsis and erroneously listed by
Desor in his table of distribution, page Lxvy, as among the Eocene Echinodermata of America.
Conrad, failing to note the error, also listed the form in his catalogue and check list.

PyGorHyNcHUS RUGOSUS Ravenel.

Pygorhynchus rugosus Ravenel, 1848, Echinide, recent and fossil, of South Carolina, p. 4, Pl. II, figs. 7, 8.
Pygorhynchus rugosus Ravenel, 1850, Cat. recent and fossil Echinidz, South Carolina, p. 160.
Pygorhynchus rugosus Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 91.

Ravenel, in 1848, published in an out of the way pamphlet two pocr drawings, unaccom-
panied by a description, of a form from the Eocene of South Carolina for which he proposed
the name Pygorhynchus rugosus. The species is not entitled to recognition; and the writer
has been unable to locate the type or to recognize the form among the material studied.

148 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Genus BREYNELLA Gregory.
BREYNELLA GREGORY! Twitchell, n. sp.
Plate LX VIII, figures la-f.
Breynella sp. Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 104. Nomen nudum.

Determinative characters —Test suboyal in marginal outline, broadest back of the center,
narrowing posteriorly, truncated vertically at the posterior end; sides and anterior end rounded;
upper surface convex, somewhat elevated, especially along the posterior median area, apex
slightly to the rear of the center; under surface rather flat, slightly concave near the peristome.
Ambulacral areas narrow, supetaloid; petals rather short, straight, flush, inconspicuous and
open at the ends. Apical system very excentric anteriorly. Peristome pentagonal, excentric
anteriorly, but somewhat less so than the apical system; with a floscelle. Periproct oblong-oval,
longitudinally elongate, supramarginal, at the top of, and flush with the vertical surface of the
posterior truncation.

Dimension.—Length 34 millimeters; width 28 millimeters; height 18 millimeters.

Deseription.—This medium-sized Breynella is the first representative of the genus to be
reported from the United States. The specimens here described are probably the same which
J. W. Gregory saw at the American Museum of Natural History, and as he first recognized the
form as a Breynella it is named in his honor. The test of this species is suboval to subovate
in marginal outline, broadest back of the center, narrowing toward the posterior end, which
is vertically truncated. The sides are rounded and inflated; the upper surface convex, some-
what elevated, especially along the posterior median area, which, however, gradually declines in
the form of a low rounded ridge on approaching the region of the periproct; the under sur-
face rather flat, tumid around the margin, slightly concave near the peristome. The apex is
slightly to the rear of the center.

The ambulacral areas narrow, widest at the ambitus, where they are only slightly wider
than the petaloid portions; dorsal portions subpetaloid, the petals being rather short, straight,
flush, inconspicuous, and open at the ends; the posterior pair slightly longer than the others,
which are nearly equal in length. The poriferous zones are rather narrow; outer row of pores
oval, inner row round; pairs of pores conjugate.

The apical system is very excentric anteriorly, being situated about one-third the length
of the test from the anterior end. Its details are not well shown on the specimens studied; but
there are four genital pores of which the anterior pair are nearer together than the posterior.

The peristome is pentagonal, transversely elongate, excentric anteriorly, but somewhat less
so than the apical system, with a floscelle. The floscelle is distinct, and the bourrelets are broad
and rather prominent; but the phyllodes are not very conspicuous.

The periproct is oblong-oval, longitudinally elongate, supramarginal, at the top of, and
nearly flush with the vertical surface of the posterior truncation. A poorly defined shallow
groove extends from the periproct down the middle of the posterior truncation.

The surface of the test is closely set with small tubercles, in deep scrobicules, which are
somewhat larger on the under surface. There appears to be a very narrow, somewhat pitted,
median band behind the peristome which extends along close to the zigzag suture line.

Related forms.—Breynella gregoryi resembles in a general way several of the Tertiary species
of Cassidulus; but is readily separated by its longitudinally elongate periproct. Its closest
American ally is Echinanthus antillarum Cotteau, from the Eocene of the West Indies, from which
it differs in having its periproct overhung by an expansion of the test. Itresembles E. bonissenti
Cotteau, from the Eocene of France, but is smaller and has its apical system more excentric
anteriorly. It also closely resembles Breynella equizoata Gregory, from the lower Oligocene of
Malta, but may be distinguished by its higher posterior margin and the slightly more anteriorly
excentric position of both its apical system and peristome.

Locality.—Santee Canal, S. C.

Geologic horizon. _ralpalbly either the Cooper marl (upper Hocene) or the upper part of
the McBean formation (middle Eocene).

Collection.—American Museum of Natural History.

EOCENE ECHINODERMATA. 149
Genus ECHINOLAMPAS Gray.
ECHINOLAMPAS APPENDICULATUS Emmons.
Plate LX VIII, figures 2a-h.

Echinolampas appendiculatus Emmons, 1858, Agriculture Eastern Counties: North Carolina Geol. Survey Rept., p. 307,
figs. 240, 241.
achinolampas appendiculatus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 697.

Determinative characters.—Test suboval to subovate in marginal outline, broad and rounded
anteriorly, narrowing in nearly straight lines to the pointed, obliquely truncated posterior end;
sides and anterior end rounded and inflated. The upper surface convex, depressed, and usually
rather flat on top, with a tumid, rounded ridge over the periproct; under surface very tumid
for a wide area around the margin, slightly concave near the peristome. Apex central or sub-
central. Ambulacral areas narrow, dorsal portions petaloid; petals narrow, some with porifer-
ous zones unequal in length. Apical system excentric anteriorly. Peristome large, elliptical,
transverse, excentric anteriorly, with an inconspicuous floscelle. Periproct large, subelliptical,
inframarginal, beneath the protruding posterior ridge.

Dimensions.—The figured form, which is about average size, gave length 33 millimeters;
width 28 millimeters; height 17 millimeters. The largest specimen gave length 48 millimeters;
width 42 millimeters; height 23 millimeters.

Description.—This species was described and figured by Emmons in 1858. It appears to
be limited to North Carolina, where it is often found in association with Cassidulus carolinensis.
In actual number of specimens it is the most abundant of the Cenozoic Cassiduloidea occurring
in the United States, the writer having had more than 300 specimens available for study. The
writer has also had the privilege of studying Emmons’s type, which is in the collection of Williams
College; and as a result has determined that in applying the name “appendiculatus”’ to the
species based upon the“ subcordate sculptured plate with a pentagonal opening, in the center of
which there is a pore”’ which was said to occupy the apical disk, Emmons made a curious mis-
take. His type does show a plate of some such character as he described but it is evidently
foreign to the test, probably a fragment of some other fossil—possibly the plate of some cidaroid
form—which has by accident become cemented to the test in the neighborhood of the apical
system. Emmons’s type is the only one of the 300 specimens examined by the writer which
possesses any such plate. Furthermore, it is difficult to conceive of any possible function for
such an appendix to an echinoid test. This species is somewhat variable in minor details, but
its broad characteristics are quite uniform and easily distinguished. The test-is thin walled,
depressed-ovoid in general form; marginal outline suboval to subovate, rounded anteriorly,
broadening back of the middle, then rapidly narrowing in almost straight, converging lines to the
rather pointed, somewhat rostrate posterior end; margin very round and highly inflated, less
so along the narrowing part on both sides of the posterior end, and downwardly and anteriorly
truncated at the posterior end. The upper surface is usually rather low, regularly convex,
depressed, rather flat on top and in the form of a tumid rounded ridge over the periproct;
though occasional specimens are moderately elevated, and somewhat ridged along the whole
longitudinal median area; under surface very tumid for a wide area around the margin,
slightly concave near the peristome. The apex is central or subcentral.

The ambulacral areas are narrow, dorsal portions petaloid; petals narrow, rather long,
varying somewhat in details on the same specimen and from specimen to specimen, the posterior
pair usually slightly longer than the anterior three, which are nearly equal in length, partly open
at their extremities. The poriferous zones are narrow, flush, the inner zones of the posterior
petals slightly shorter than the outer zones, and in a less degree the anterior zones of the anterior
paired petals shorter than the posterior zones; outer row of pores oval, inner row round; pairs
of pores conjugate, the ridges between the pairs of pores prominent and ornamented with a row of
granules.

The surface of the test is highly ornamented. There are numerous small tubercles in wide,
deep scrobicules. On the under surface the scrobicules are more numerous, different in size and

150 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

shape and closer together; on the upper surface they are more scattered and in granulated rings
between which the surface is dotted with numerous small pits.

The apical system is excentric anteriorly and consists of four perforated basal plates, the
anterior genital pores being closer together than the posterior, five small perforated radial plates,
and a large, central, granulated, faintly tumid madreporite.

The peristome is rather large, regularly elliptical, transverse, excentric anteriorly, though
slightly less so than the apical system, surrounded by an inconspicuous floscelle with straight
feeble phyllodes and faintly defined, slightly tumid bourrelets.

The periproct is rather large, irregularly elliptical, the upper edge being less convex than the |
lower edge and constituting the extreme protruding posterior end of the test, inframarginal,
beneath the overhanging rounded ridge of the posterior upper surface and level with the down-
wardly oblique truncation of the posterior margin.

Related forms.—Echinolampas appendiculatus is not closely allied to any other American
species. It is easily distinguished from £. aldrichi, the only other representative of the genus
yet reported from the United States. It resembles rather closely Echinolampas francei Desor
from the Eocene of France but differs in being relatively broader and in having a more regularly
elliptical peristome.

Localities —Newbern, (Emmons), Rocky Point (figured form), Smith Creek, and Wil-
mington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collections.—Williams College; U. S. National Museum (138017); Johns Hopkins University.

Suborder STERNATA.
Family SPATANGID®.

Genus HEMIPATAGUS Desor.

H»mirpaTacus arGuTus Clark, n. sp.
Plate LXIX, figures la-d.

Determinative characters—Test small, cordiform, depressed, highest just back of posterior
truncation, nearly as broad as long, nearly flat below, with broad anterior suleus. Ambulacra
nearly flush, with slightly depressed poriferous avenues. Interambulacra are broad, the paired
area with several widely scattered rather large, crenulate and perforate tubercles, with deep
areolas giving the surface an irregularly pitted appearance. The lower flat surface has many
tubercles of similar character especially on the sides near the ambitus. The tubercles are much
worn on both the upper and lower surfaces of the specimen.

Description.—The single specimen of this very beautiful form has a small test, cordiform in
outline, somewhat depressed and nearly as broad as long. The upper surface is flattened ante-
riorly and elevated posteriorly just back of the posterior truncation. A broad anterior sulcus
crosses the ambitus. The lower surface is nearly flat.

The ambulacra are nearly flush, the poriferous avenues being slightly depressed, subpetal-
oidal, the anterior pair being shorter than the posterior.

The interambulacra are broad, the paired areas with several widely scattered rather large,
crenulated and perforate tubercles, with deep areolas giving the surface an irregularly pitted
appearance. The lower flat surface has many tubercles of similar character especially on the
sides near the ambitus. The tubercles are much worn on both the upper and lower surfaces of
the specimen.

The apical system is indistinct. The peristome is large and oval in outline. The periproct
is large and supramarginal in position.

Related forms.—The species is similar in certain features to H. subrostratus but is wider
anteriorly, has a more cordate form, and is higher posteriorly.

Locality.—Enterprise, Clarke County, Miss.

Geologic horizon.—Claiborne group, middle Eocene.

Oollection.—U. S. National Museum (141107).

EOCENE ECHINODERMATA. 151

HEMIPATAGUS SUBROSTRATUS Clark, n. sp.
Plate LXIX, figures 2a-b.

Determinative characters.—Test medium size, subcordiform, only slightly higher posteriorly,
longer than wide, nearly flat below, with broad anterior sulcus. Ambulacra broad, somewhat
depressed, the poriferous avenues subpetaloidal, the anterior pair longer than the posterior.
Interambulacra with a number of large scattered tubercles in the paired areas with deep areolas,
crenulate and perforate.

Dimensions.—Length 33 millimeters; width 29 millimeters; height 14 millimeters.

Description.—The single specimen of this species is much damaged on the lower surface
and posterior end, neither the peristome nor periproct being preserved. The testis of medium
size, subcordiform, only slightly higher on the posterior part than on the forward part of the
upper surface. It is longer than wide, the widest portion being only slightly forward of the
middle of the test. A broad anterior sulcus extends from the apex over the ambitus. The
lower surface is nearly flat.

The ambulacra are nearly flush, somewhat depressed, the poriferous avenues subpetaloidal,
the anterior pair longer than the posterior. The pores are oval and connected by prominent
furrows.

The interambulacra are somewhat elevated with a number of large, scattered tubercles in
the paired areas. The tubercles have deep areolas, and are crenulate and perforate.

Related forms.—This species is similar to H. argutus but is narrower anteriorly, has a less
cordate form, and is lower posteriorly.

Locality Wilmington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collection.—U. S. National Museum (164652).

Genus SCHIZASTER Agassiz.
ScHIZASTER LECONTEI Merriam.
Plate LXIX, figures 3a-b.

Schizaster (?) sp. Merriam, 1897, Jour. Geology, vol. 5, p. 773.
Schizaster lecontei Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, pp. 164, 165, Pl. XX, figs. 1, la.
Schizaster lecontei Stefanini, 1911, Soc. Geol. italiana Boll., vol. 30, p. 697.

Determinative characters.—Test small, cordiform, elevated, with a sharp ridge from apical
system to posterior truncation. Apex posterior to center of test. Ambulacra broad, depressed,
petals of posterior pair less than half the length of anterior. Peripetalous fasciole distinct.
Apical system posterior to center. Peristome well forward. Periproct high on truncated
posterior surface.

Dimensions.—Length 20 to 23 millimeters.

Description.—The specimens of this species are preserved only as impressions or casts,
badly crushed. The test is small, cordiform, upper surface much elevated, with a sharp ridge
running from the apical system to the posterior truncated surface. A broad groove notches
the anterior margin.

The ambulacra are broad, the poriferous zones depressed, petaloidal, the petals of the
posterior pair very short, less than half the length of the anterior, sometimes almost circular in
outline. Pores elongated, apparently yoked.

The interambulacra broad. Tubercles larger on the lower surface. Peripetalous fasciole
quite distinct on one specimen. Traces of what appears to be the lateral fasciole have been
seen beneath the periproct.

Apical system excentric, posterior, anterior to the summit.

Peristome well forward, broad two-lipped. Periproct high up on the truncated posterior end.

52 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Merriam says: ‘‘Numerous large spines much like those of Schizaster have been found at
one locality, but if they belong to this genus at all they were probably derived from another and
much larger species.”’

Locality.—Contra Costa County, Cal.

Geologic horizon.—Martinez and Tejon formations, Eocene.

Collection.—University of California.

SCHIZASTER ARMIGER Clark, n. sp.

Plate LXX, figures la-d.

Determinative characters.—Test rather large, cordiform, depressed upper surface slopes at
first rapidly then more slowly from anterior margin to apical system, beyond which an elevated
sharp ridge continues to the truncated posterior margin. Ambulacra in broad deep furrows,
the paired ambulacra in moderately sunken petals, the anterolateral being about one and one-
half times as long as the posterolateral. Peripetalous and lateral fascioles distinct.

Dimensions.—Length 53 millimeters; width 46 millimeters; height 22 millimeters.

Description.—This species has a test of moderately large size, much depressed and clearly
cordiform in marginal outline. The upper surface slopes at first rapidly from a sharp anterior
margin to near the apical system when it becomes nearly flat for a short distance. Beyond
the apical system a sharp elevated ridge highest near the middle point continuous on to the
truncated posterior margin.

The ambulacra are broad, the single anterior ambulacrum being situated in a deep broad
groove that deeply indents the anterior margin. The paired ambulacra have broad deep petals,
the anterolateral being somewhat over one and a half times as long as the posterolateral.

The interambulacra are more or less flat, slightly gibbous, the posterior much elevated
forming a sharp ridge. The surface is thickly covered with small perforate tubercles. The
peripetalous and lateral fascioles are very distinct.

The peristome is near the anterior margin in a shallow depression. The periproct is high
on truncated posterior margin.

Locality.—Cocoa post office, Choctaw County, Ala.

Geologic horizon.—St. Stephens limestone (lower part), upper Eocene.

Collection.—U. 5. National Museum (141104).

SCHIZASTER sp.
Plate LXX, figure 2.

Fracment of spatangoid test, Clark, 1901, Maryland Geol. Survey, Eocene, p. 232, Pl. LXT, fig. 1.

Description.—A fragment of a spatangoid test found among the Eocene materials collected
at Evergreen, Va., apparently belongs to the genus Schizaster, to which it is here referred. A
portion of an ambulacrum with the adjacent portion of an interambulacrum, showing many
characteristic features, is preserved. The ambulacrum, probably one of the anterolateral pair,
is petaloidal, the petal sunken and rather narrow. The interambulacrum is somewhat gibbous
and has preserved a part of a peripetalous fasciole.

Locality.—Bvergreen, Va.

Geologic horizon.—Nanjemoy formation, middle Eocene.

Collection.—Johns Hopkins University (T 2001).

Genus LINTHIA Merian.
LANTHIA WILMINGTONENSIS Clark, n. sp.
Plate LXX, figures 3a-c.

Determinative characters —Test large, cordiform, gibbous above, nearly flat below, ambu-
lacra wide, anterior in deep groove, anterolateral with petals in long deep grooves, postero-
lateral with petals about one-half the length of the anterolateral and also deeply sunken. Inter-

EOCENE ECHINODERMATA. 1U5y3}

ambulacra wide, prominent, and covered with numerous small tubercles. Peristome in promi-
nent depression.

Dimensions —Length 56 millimeters; width 55 millimeters; height 34 millimeters.

Description. —This relatively large form has an elevated, gibbous upper surface and a nearly
flat lower surface except for the peristome depression. It is cordiform in marginal outline
about as wide as long and rounded laterally.

The ambulacra are wide, the single anterior ambulacrum being situated in a deep groove,
which deeply indents the margin. The anterolateral paired ambulacra have long, broad sunken
petals, while those of the posterolateral pair are only about half as long.

The interambulacral plates are covered with small perforated tubercles. The peripetalous and
lateral fascioles can be readily traced.

The peristome is in a pronounced depression near the anterior margin. The periproct is not
shown on the type form.

Locality —Wilmington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collection —U. S. National Museum (166482).

LINTHIA ALABAMENSIS Clark, n. sp.
Plate LX-XI, figures la-d, 2a-d.

Determinative characters —Test small, nearly round, except for groove on anterior margin and
slight truncation posteriorly, low, somewhat depressed, the upper surface sloping gradually
toward the apex. Ambulacra narrow, not deeply sunken, the posterolateral petals much shorter
than the anterolateral. Peristome near anterior margin. Periproct relatively high on narrow
truncated posterior margin.

Dimensions —Large specimen: Length 34 millimeters; width 35 millimeters; height 19
millimeters. Small specimen: Length 22 millimeters; width 22 millimeters; height 14 milli-
meters.

Descruption.—The test of this species is small, low, somewhat depressed, nearly round in
ambital outline, except for the rather shallow groove on the anterior margin and the slight, nar-
row truncation on the posterior margin. The upper surface slopes gradually from the anterior
margin posteriorly.

The ambulacra are narrow and not deeply sunken. The single anterior ambulacrum is
situated in a narrow, rather shallow groove. The anterolateral paired ambulacra have long,
narrow, rather shallow petals, and the posterolateral pair are short and shallow.

The interambulacral plates are covered with small perforate tubercles. The peripetalous
and lateral fascioles are not easily traced.

The peristome is in a shallow depression near the anterior margin. The periproct is situated
relatively high on the narrow truncated posterior margin.

Localities —Prairie Creek, Wilcox County, Ala.; near Grand Glaise, Jackson County, Ark.

Geologic horizon—Midway group, lower Eocene.

Collection.—U. S. National Museum (166483, 173371).

Genus EUPATAGUS Agassiz.
EUPATAGUS CAROLINENSIS Clark, n. sp.
Plate LXXI, figures 3a-d, 4.

Determinative characters—Test medium size, oval, moderately tumid, nearly flat along the
median line, with slight keel. Ambulacra depressed, anterior very slightly, paired ambulacra
in shallow grooves, long, the anterolateral pair shorter than the posterolateral. Interambulacra
slightly tumid. Apical system excentric, well forward. Peristome excentric in front.

Dimensions —Length 48 millimeters; width 39 millimeters; height 22 millimeters.

Description.—This very beautiful form has a test of moderate size, oval, moderately tumid
on the upper surface and sloping up at a low angle along the median line toward the posterior

154 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

ridge, which is low. The posterior margin is slightly contracted. The lower surface is nearly
flat, with a slight posterior keel. :

The ambulacra are broad, the anterior ambulacrum occupying a slight depression and the
paired ambulacra slight grooves in the petaloidal portions. The petals are long, the postero-
lateral being longer than the anterolateral. The pore pairs are rather large and connected by
furrows.

The interambulacra are shghtly tumid, the tubercles on the lower surface bemg tnuch larger
than on the upper surface.

The apical system is small and situated well forward. The peristome is large, semilunar
in shape, and excentric in front. The peripetalous fasciole is clearly defined.

Locality —Wilmington, N.C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collection—U. 8S. National Museum (164674, 166484).

Genus BRISSOPSIS Agassiz.
BRISSOPSIS RIMULATUS Ravenel.

Brissopsis rimulatus Ravenel, 1848, Echinoide, recent and fossil, of South Carolina, p. 4, Pl. II, figs. 3 and 4.
Brissopsis rimulatus Ravenel, 1850, Am. Assoc. Adv. Sci. Proc., vol. 3, p. 160.
Brissopsis rimulatus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 708.

Description—Ravenel did not describe this species in 1848 when he proposed the name,
but he published two very distinctive figures, which should be sufficient to identify the form if
material representing the species should be found. No such material was at hand when this
monograph was under preparation. i

Locality —South Carolina (Ravenel).

Geologic horizon.—Kocene (?).

Collection —Unknown.

Genus MACROPNEUSTES Agassiz.

MACROPNEUSTES CAROLINENSIS Clark, n. sp.
Plate LX XI, figures 5a-d.

Determinative characters —Test small, elevated, tumid, subpentagonal. Apical system
excentric forward. Ambulacra narrow, petaloidal portions in narrow, shallow grooves. Surface
of plates covered with numerous tubercles. Peristome about one-third the distance from the
anterior to the posterior margin.

Dimensions —Length 28 millimeters; width 27 millimeters; height 22 millimeters.

Description —This attractive little form has an elevated test, tumid in form, and subpentag-
onalin ambital outline. The apexis excentric forward. The marginisrounded.- The ambulacra
are narrow, the petaloidal portions being elongate in narrow, shallow grooves. The petals are
imperfectly closed. The surface of the plates is covered with numerous, irregularly dispersed
eranules. The peristome is large, excentric, situated about one-third of the distance from the
anterior to the posterior margin; irregularly dispersed tubercles. The interambulacra are slightly
gibbous above, the margin sharp, and the lower surface nearly flat. The fascioles are rather
indistinct.

The peristome is large, semilunar, with large projecting posterior labrum. The periproct.
is large and low on the imperfectly truncated posterior surface.

Locality.—Wilmington, N. C.

Geologic horizon.—Castle Hayne limestone, upper Eocene or Oligocene.

Collection —U. S. National Museum (164651).

EOCENE ECHINODERMATA. 155

MacROPNEUSTES MORTONI (Conrad).

Plate LX XII, figures la-d.

Holaster mortoni Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 40, Pl. 1, fig. 10.
Holaster mortoni Boyle, 1893, U. 8. Geol. Survey Bull. 102, p. 150.
Macropneustes mortoni Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 700.

Determinative characters—Test large, clevated, tumid, slightly cordiform, nearly round,
apex excentric forward. Ambulacra broad, petaloidal portions clongate, in very shallow
depressions, nearly flush. Surface of both ambulacral and interambulacral plates outside the
petals covered with numerous irregularly dispersed tubercles. Peristome forward about one-
third the distance from the anterior to the posterior margin. Periproct large, short distance
above margin.

Dimensions.—Length 84 millimeters; width 86 millimeters; height 52 millimeters.

Deseription.—The test of the species is large, elevated, and tumid. It is slightly cordi-
form in ambital outline, nearly round but for the slight anterior groove and the ill-defined
posterior truncation. The apical system is excentric forward, the high upper surface giving
the test a somewhat subconical form.

The ambulacra are broad, the petaloidal portions elongate, nearly flush in very shallow
depressions that reach far down the sloping sides.

The petals of the ambulacra outside the petaloidal portions of the ambulacra and the
interambulacra are covered with numerous irregularly dispersed tubercles.

The peristome is large, excentric forward, situated about one-third of the distance from
the anterior to the posterior margin. The periproct is large and situated a short distance
above the margin.

Localities.—Palmyra, Lee County, Ga. (type); Fail, Choctaw County, Ala. (figured specimen).

Geologic horizon.—Jackson formation (upper Eocene) and Vicksburg formation (lower
Oligocene).

Collection.—U. 8. National Museum (146468).

Genus SARSELLA Pomel.
SARSELLA GREGORY! Clark, n. sp.

Plate LXXII, figures 2a-d.
Sarsella sp. Gregory, 1892.

Determinative characters.—Test small, cordiform, depressed. Apical system nearly cen-
tral. Ambulacra very diverse anterior in broad deep group, petaloidal portions of paired
ambulacra slightly sunken, the posterolateral more than the anterolateral. Several large,
irregularly dispersed tubercles crenulate and perforate on the interambulacra. Peristome
semilunar. Periproct high on posterior truncation.

Dimensions.— Length 18.5 millimeters; width 17.5 millimeters; height 9 millimeters.

Description.— This small form was noted by Gregory in his cursory examination of Ameri-
can echinoids when in America in 1891 and was referred to the genus Sarsella. The test is
‘small cordiform in ambital outline, depressed, only slightly higher on the posterior portion
of the upper surface than the anterior. The under surface is nearly flat.

The ambulacra are very diverse. The anterior ambulacrum is situated in a broad deep
groove. The paired ambulacra have diverse slightly sunken petaloidal areas, the petals of the
posterolateral pair being broader and shorter and closed below while those of the anterolateral
pair are only imperfectly closed.

The surface of the interambulacral plates bears a number of irregularly dispersed large
erenulate and perforate tubercles. They are confined to the paired interambulacra.

The apical system is small. The perforations in the four genitals are distinct on the type
specimen.

156 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The peristome is large, semilunar, and distinctly excentric forward. The periproct is
large, high on the posterior truncation.

Locality.— Santee Canal, S. C.

Geologic horizon.— Santee marl member of McBean formation, of Claiborne group, middle
Eocene.

Collection.— American Museum of Natural History.

SPATANGUS? PACHECOENSIS (Pack).

Spatangus ? pachecoensis Pack, 1909, Univ. California Dept. Geology Bull., vol. 5, No. 18, p. 276, Pl. XXIII, figs. 4,5.
Spatangus ? pachecoensis Lambert, 1910, Rev. crit. paléozoologie, 4° année, No. 1, p. 55.
Spatangus ? pachecoensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

Description.— The species was established by Pack on casts of poorly preserved fragments.
It apparently belongs to the Spatangide, but its generic relations can not be determined.
Lambert, on the other hand, positively refers it to the Scutellide and considers the material
too fragmentary for specific description.

Locality — Northwest of Pacheco, Contra Costa County, Cal.

Geologic horizon.— Tejon formation, upper Hocene.

Collection.— University of California.

OLIGOCENE ECHINODERMATA.
Class ECHINOIDEA.
Subclass REGULARIA ENDOBRANCHIATA.
Order CIDAROIDEA.

Family CIDARID®.

Genus CIDARIS Leske.
CIpARIS MORTONI Conrad.

Plate LX-XIII, figure 1.
Cidaris mortont Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 40, Pl. I, fig. 13.
? Cidaris sp. Bouvé, 1851, Boston Soc. Nat. History Proc., vol. 4, p. 3.
Cidaris mortoni Cotteau, 1892, Paléontologie francaise, Echinides éocénes, p. 449.
Cidaris mortoni, Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.

Description —The fragment of a Cidaris test, which is here figured and referred to Cidaris
‘mortoni, has all of the essential characteristics of the form figured and briefly described by
Conrad. The species is large, globose, and circular in ambital outline. The ambulacra are
straight, the pore openings round and somewhat distinct. The interambulacra are composed
of large plates, each bearing a large perforate and apparently uncrenulate tubercle.

Localities —Near Palmyra, Lee County, Ga. (type); Baker County, Ga. (figured specimen).

Geologic horizon.—Vicksburg formation, lower Oligocene.

Collection.— Boston Society of Natural History (1555).

Crparis smiTut Clark, n. sp.
Plate LX XIII, figures 2a-c, 3. 2

Determinative characters —Test medium size, moderately tall, subcircular in ambital out-
line. Ambulacra narrow, slightly flexuous. Interambulacra broad, each with two rows of
primary tubercles perforate and crenulate, the areola surrounded by a row of secondary tuber-
cles. Miliary space small.

Dimensions.—Diameter 35 millimeters; height 24 millimeters.

Description.—The test of this species is of medium size, moderately tall, and subcircular
in ambital outline.

The ambulacra are narrow, slightly flexuous, the poriferous zones separated by four rows
of granules at the ambitus, which become reduced to two rows both above and below.

The interambulacra are wide, rather more than three times the width of the ambulacra.
Each plate bears a large primary tubercle which is perforate and crenulate and has a medium-
sized areola surrounded by a row of granules. The relatively narrow miliary space is thickly
covered with tubercles.

A large tubercle was found with the test that probably belongs to the same species. Cer-
tain Cidaris spines found at the Central Salt Works, Clarke County, Ala., may represent the
same species.

Locality —Thé Rocks, Clarke County, Ala.

Geologic horizon.—St. Stephens limestone (upper portion), lower Oligocene.

Collection —Alabama Geological Survey.

39800°—15——11 157

158 MESOZOIG AND CENOZOIG ECHINODERMATA OF THE UNITED STATES.

CIDARIS GEORGIANA Clark, n. sp.
Plate LX-XIII, figure 4.

Determinative characters—Test moderately high, subcireular, medium size. Ambulacra
wide, with large primary tubercle on each plate, the tubercles on contiguous plates closely
approximate, wide miliary space between the rows of tubercles.

Dimensions.—Diameter 38 (?) millimeters; height 25 (?) millimeters.

Description.—The test of this species 1s only partly preserved. It shows, however, the
chief determinative characters. It is evidently unlike any other form hitherto described.
The test is of medium size, moderately high, and subcircular in ambital outline. The full
height and diameter can not be with certainty determined. The ambulacra are rather broad
and straight, with four rows of granules between the poriferous zones.

Locality.—Muckafoonee Creek, Ga.

Geologic horizon.—Vicksburg formation, lower Oligocene.

Collection—U. 8. National Museum (166485).

CIDARIS BRANNERI Arnold.

Plate LX XIII, figure 5.

Cidaris branneri, Arnold, 1903, U. S. Nat. Mus. Proc., vol. 29, pp. 363, 364, Pl. XX XIII, fig. 5.
Cidaris branneri Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 698.
Description—Arnold says:

Test unknown. Spines, long, slender, circular in cross section, attaining a length of at least 25 millimeters and a
diameter of over 2 millimeters. Surface of spine smooth for about one-fifth its length from the base; above this it is
ornamented by ten longitudinal rows of elongated nodes or granules which are barely connected near the smooth
portion, but which partake more and more of the character of nodose ribs toward the distal end; the last one-fifth of the
spine is ornamented by five prominent, slightly nodose ribs; the extreme end is blunt and rounded; collar at base only
faintly developed.

The spines of this species are easily distinguishable from those of C. merriami, new species, from the Eocene, by
their smaller size, fewer but much more prominently nodose longitudinal ribs, and smooth basal portion. No complete
spine of C. merriami was obtained, so that the smooth basal section may possibly be a characteristic of this latter species
as well as of C. brannert.

Dimensions.—Length 20 millimeters; diameter, basal end 2.2 millimeters, distal end 1.1
millimeters. :

Localities —Santa Cruz quadrangle, Santa Cruz County, locality No. 109 on Bear Creek, 4
miles above its confluence with the San Lorenzo River, Cal.

Geologic horizon.—San Lorenzo formation, upper Oligocene.

Collection —U. 8S. National Museum (1056). -

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder ARBACINA.

Family ARBACIIDA.
Genus CHLOPLEURUS Agassiz.
C@LOPLEURUS ALDRICHI Clark, n. sp.
Plate LX XIII, figures 6a—b, 7a-c.

Determinative characters—Test large, subpentagonal, tumid at ambitus, depressed above,
nearly flat below. Ambulacra narrow, the two rows of primary tubercles becoming very small
toward the apex; poriferous zones narrow and straight, the pore pairs uniserial. Interam-
bulacra wide, each with several rows of large primary tubercles at ambitus reduced to two
around peristome and on upper surface, leaving wide median area above. Tubercles with flat
areolas and large imperforate mamelons. Peristome with very slight branchial incisions.

OLIGOCENE ECHINODERMATA. 159

Dimensions —Specimen A: Diameter 38 millimeters; height 20 millimeters. Specimen B:
Diameter 28 millimeters; height 12 millimeters.

Description—The species is characterized by a rather large test, with subpentagonal out-
line. It is tumid at the ambitus and depressed on the upper surface. It is nearly flat below.
The ambulacra are narrow, each bearing two rows of primary tubercles that diminish rapidly
in size from the ambitus toward the apex. The poriferous zones are narrow, the pore pairs
being uniserial and somewhat crowded toward the apex. The interambulacra are wide with
several rows of primary tubercles at the ambitus which become reduced to two toward the peri-
stome and above the ambitus, where a broad median area devoid of tubercles occurs. The
peristome is small with slight branchial incisions.

The several specimens examined are much broken and the surfaces much worn.

Locality —Perdue Hill, Ala.

Geologic horizon.—St. Stephens limestone (upper portion), lower Oligocene.

Collection —U.S. National Museum (T. H. Aldrich).

Suborder DIADEMINA.
Family CYPHOSOMATID. °
Genus GAGARIA Duncan.
GAGARIA AMERICANA Clark, n. sp.
Plate LX-XIII, figures 8a-b.

Determinative characters—Test small, circular, tumid, subhemispherical, concave below.
Ambulacra narrow, each with two rows of small primary tubercles, perforate and crenulate;
each compound plate with three pairs of pores. Interambulacra wide, each with two rows of
primary tubercles. Apical system large, flush.

Dimensions.—Diameter 14 millimeters; height 8 millimeters.

Description —This beautiful ferm has a very small test, with a circular ambital outline.
It is tumid, subhemispherical, rather depressed above, concave below. The ambulacra are
narrow, each area provided with two rows of perforate and crenulate primary tubercles which
are longest at the ambitus and reach to the apical system, gradually diminishing in size. The
poriferous zones are narrow, the pore pairs being three in number on each compound plate.
The interambulacra are broad, each carrying two rows of primary tubercles similar to the ambu-
lacra between which are many small secondaries and granules. The apical system is large and
flush.

This species is based on a single specimen, the peristomial region of which is much damaged.

Locality.—The Rocks, Clarke County, Ala.

Geologic horizon.—St. Stephens limestone (upper portion), lower Oligocene.

Collection.—U. S. National Museum (T. H. Aldrich). E

Suborder ECHININA.

Family TRIPLECHINID®.

Genus ECHINUS Linné.
Ecurnus? sp.
Echinus sp. Cunningham, 1895, Am. Micr. Jour., vol. 16, pp. 193-196, figs.

Description —Small spines and fragments of plates are figured by Cunningham from ‘‘cal-
careous marl”’ in Clarke County, Miss., and referred to the genus Echinus. It is quite impossible
to determine definitely the generic relations of these forms.

Locality —Red Bluff station, Chickasawhay River, Clarke County, Miss.

Geologic horizon.—Vicksburg limestone, lower Oligocene

Collection K. M. Cunningham, Mobile, Ala.

160 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Subclass IRRHGULARIA.

Order GNATHOSTOMATA.
Suborder CLYPEASTRINA.
Family FIBULARIID#.

Genus ECHINOCYAMUS Phelsum.
EcurnocyaMus VAUGHANI Twitchell, n. sp.
Plate LX XIV, figures la—d.

Determinative characters.—Test very small, though larger than related American species,
thick walled, almost regularly ege shaped, though elongated longitudinally, about twice as long
as broad. Upper surface elevated, both upper and lower surfaces flattened along the longi-
tudinal median areas. Apical system anteriorly excentric, with four medium-sized genital
pores. Petals relatively short and petaloidal area smaller than in related forms. Peristome
relatively large, central, slightly depressed; periproct very small, close to peristome.

Dimensions.—Length, 8 millimeters; width, 4 millimeters; height, 4 millimeters.

Description.—This species is founded upon a specimen collected in Georgia by T. Wayland
Vaughan, of the United States Geological Survey, in whose honor it is named. The test,
though actually very small, is larger than in the other American representatives of the genus.
The test is thick walled, elongate egg shaped in general form, elongate subelliptical to elongate
subovate in marginal outline, somewhat pointed anteriorly, about twice as long as broad. The
upper surface is high (the height of the test equalling the breadth) and flattened longitudinally;
under surface also flattened somewhat along the longitudinal median area and slightly concave
around the peristome.

The ambulacral petals are rather well defined, relatively short, a making the petaloidal
area relatively smaller than in allied American Fromme petals wide open at ends; ; poriferous zones
diverge in almost straight lines to the ends and gomsiist of small round pores in pairs not dis-
‘ying conjugated.

The peristome is relatively large, central, slightly depressed below the surface; periproct
very small, about one-third the diameter of the peristome and very close to the peristome.

Related forms.—E. vaughani is most closely related to EH. texanus but can be readily sepa-
rated by its larger size, less oval marginal outline, more pointed anterior end, greater difference
between its longitudinal and transverse diameters, and smaller petaloidal area. E. vaughani
also resembles #. parvus and E. hualeyanus but differs from both in having its periproct near
the peristome. It also differs from EL. hualeyanus in being less fragile and less depressed.

Locality.—Little Horseshoe Bend, Flint River, Ga.

Geologic horizon.—Vicksburg formation, lower Oligocene.

Collection.—U. S. National Museum (166486).

Family LAGANIDA.
Genus LAGANUM Blainville.
LaGaNuM ELDRIDGE! Twitchell, n. sp.
Plate LX XIV, figures 2a-d.

Determinative characters.—Test large, subpentagonal to subdecagonal in marginal outline,
longitudinally elongate, truncated at the anterior and posterior ends, more or less undulating
along the sides. Whole form greatly depressed, margin thin but thicker than slightly concave
submarginal area, petaloidal region tumid. Apex and apical system subcentral. Lower surface
flat. Ambulacral petals long, lommatte elliptical, extending two-thirds the way to the margin,
pointed and closed at the ends; pairs of pores conjugated by very narrow more or less wavy
grooves. Ambulacral areas very wide at margin, narrowing rapidly to ends of petals. Peri-
stome moderate in size, subcentral, subpentagonal to subelliptical, transversely elongate.

EOCENE ECHINODERMATA. 16],

Ambulacral grooves apparently simple and straight, each groove having a fine line on both
sides which rapidly diverge from the main groove. Periproct relatively large, suboval, longi-
tudinally elongate, one-fourth the way from the margin to the peristome.

Dimensions.— Length 96 millimeters; width 75 millimeters; height 10 millimeters.

Description.— The only specimens known of this large and handsome Laganum, the largest
representative of the genus from American deposits, were collected in Florida by the late
G. H. Eldridge of the United States Geological Survey and the species is therefore named in
his honor. The test is large, being 3 to 4 inches long and 24 to 3 inches wide. In marginal
outline it is subpentagonal to decagonal, decidedly longer than broad; margin thin but thicker
than the submarginal area, truncated at anterior and posterior ends, more or less undulating
along the sides. The whole form is greatly depressed, the upper surface slightly concave around
the submarginal area, arising centrally in the form of a low mound which involves the whole
petaloidal area; apex subcentral; lower surface flat.

The ambulacral areas are very wide at the margin, being there about four times the width
of the interambulacral areas, narrowing rapidly to near the ends of the petals. The petals are
long, elliptical in outline, extending two-thirds the way to the margin, pointed and closed at
the ends. The anterior pair shorter than the other three, which are subequal in length. The
poriferous zones are wide, more than half the width of the rather narrow interporiferous areas,
inner row of pores elliptical, outer row very narrowly slitlike, hardly discernible, pairs of pores
conjugated by very narrow more or less wayy grooves.

The interambulacral areas are very narrow at the margin, widen rather rapidly to near
the ends of the petals, and narrow again toward the apical region. The whole test is closely
set with very small tubercles, among which are scattered at irregular distances some larger ones
in deep scrobicules.

The apical system is subcentral, at the summit of the tumid area. There are four large
genital pores, of which the anterior pair are set closer together than the posterior pair. No
other details could be made out on the specimens.

The peristome is of moderate size, subcentral, slightly to the rear of the apical system,
subpentagonal to subelliptical, transversely elongate. The details of the ambulacral grooves
could not be made out satisfactorily on the specimens studied. As they leave the peristome
there appears to be a single straight groove on each side of which are two fine lines which rapidly
diverge from the main groove. These side lines may be the boundary lines of what on better
preserved specimens Poul prove to be finely g granulated areas, thus forming a peristomial star.

The periproct is relatively large, about half the size of the peristome, subovall longitudinally
elongate, situated about one-fourth the way from the margin to the peristome.

Related forms.—L. eldridgei is readily distinguished from all other American forms. It
closely resembles L. elongatum Agassiz,‘ whose origin is unknown and which is not even stated
to be fossil, being very similar in size, gener al low, and marginal outline, but differs from it
in haying a suboval instead of circular periproct, placed a little farther from the posterior margin.

aaaliin— —Suwanee River, Fla. %. 4o«4 0, Uy eek bk Sep frag, Spreng, 2%,

Geologic horizon.—V. “gesiomns group, lower Oligocenc. " = % “# >"

Collection.—U. S. National Museum (164683).

LAGANUM ARCHERENSIS Twitchell, n. sp.
Plate LXXV, figures la-d.

Determinative characters.—Test small, subpentagonal to subdecagonal in marginal outline.
General form subdiscoidal, upper surface very low, nearly parallel with lower surface, with a
slightly concave ring involving most of ambulacral petals between the faintly tumid apical
region and the notably thickened margin. Highest part of test along anterior margin. Lower
surface flat. Ambulacral petals subelliptical, extending two-thirds the way to the margin,
ends closed. Apical system slightly excentric anteriorly, with four genital pores set unusually
far apart. Peristome small, pentagonal, central; ambulacral grooves simple, straight lines

1 Monographies d’échinodermes vivans et fossiles, vol. 2, Des scutelles, pp. 117-118, I'l. XXTV, figs. 1-2.

162 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

flanked by finely granulated areas, the five constituting a peristomial star. Periproct small,
transversely suboval, about one-fourth the way from margin to peristome.

Dimensions.—Length 18 millimeters; width 16 millimeters; height 3.5 millimeters.

Description.—Only a single specimen of this new Laganum has been discovered. It was
found at Archer, Fla., whence the name here given. The test is small, subpentagonal or sub-
decagonal in marginal outline. The whole form is greatly depressed; subdiscoidal, the upper
surface being practically parallel with the lower; the apical region faintly tumid, the area
between the apical region and the margin slightly concave; the margin notably andokoned.
slightly less so posteriorly than anter ‘onl The lower ee is flat. The highest part of the
test is along the surface of the anterior margin, from whence the upper sunioes slopes gently
to the posterior margin, the central tumidity being hardly any higher than the side margins.

The ambulacral petals are subelliptical, extending about two-thirds the way to the margin,
the larger part of each petal being depressed so as to form a part of the concave ring on the
upper surface, the ends of the petals practically closed. The poriferous zones are rather wide,
about half as wide as the interporiferous areas, the proximal ends poorly defined, the inner
row of pores round, the outer row slitlike, the pairs of pores conjugated.

The itaglemoarsaTovvloes al areas are very narrow, especially at the margin, where they are hardly
more than one-third as wide as the ambulacral areas. The whole surface of the test, including
the interporiferous areas and apical region, is covered with small tubercles set in deep scrobicules,
which are larger on the under surface.

The apical system is slightly excentric anteriorly at the summit of the faintly tumid central
area. There are four large genital pores, set unusually far apart, the anterior pair being nearer
together than the posterior pair. The poriferous zones could not be seen to come together at
the proximal ends, and the perforations in the radial plates could not be decane on the
specimen.

The peristome is small, central, pentagonal. The ambulacral grooves each consist of a
central impressed line and two narrow areas of fine granulation which are bounded by faint
lines; these grooves are quite distinct for a short distance from the peristome, thus constituting
a well-defined peristomial star, they then become gradually less distinct, so that as the margin is
approached they can hardly be discerned.

The periproct is small, about half the diameter of the peristome, transversely suboval,
about one-fourth the way from the margin to the peristome.

Related forms.—L. archerensis is most closely related to L. dalli, but can be easily dis-
tinguished by the concave ring on its upper surface, by its narrower petals, its less depressed
smal narrower poriferous zones, and by having its periproct closer to the margin. It is also
allied to L. floridanum, but has a less aesqulariky oval marginal outline and a linear petaloidal
area. It differs from ZL. crustuloides in being lower centr ally, in having a concave ring on its
upper surface, and in having a flat lower sintiocce,

Locality. ane, Fla. -

Geologic horizon.—Vicksburg group, lower Oligocene.

Collection.—U. S. National Museum (164667a).

Laganum jJouHnsoni Twitchell, n. sp.
Plate LX XV, figures 2a—-d.

Description and determinative characters.—The test of this new Laganum is moderate in
size and almost regularly oval in marginal outline. The upper surface is moderately elevated
centrally, the height being about one-third of the width, the tumid area extending to the ends
of the petals; the submarginal area about equal in thickness to the margin, which is slightly
undulating, very thick, high and rounded, thicker and higher than in related forms, slightly
thinner at the middle of the posterior end than elsewhere. The lower surface is decidedly
concave, the concayity reaching nearly to the margin and near the peristome being about
equal to one-half the height of the test. The apex is subcentral. The posterior petals are

- OLIGOCENE ECHINODERMATA. 163

lanceolate, the anterior three subelliptical, all of them pointed and closed at the ends, extending
two-thirds or more of the way to the margin, the anterior pair slightly shorter than the rest.
The poriferous zones are very narrow, much narrower than the slightly tumid interporiferous
areas, sometimes irregular, inner ends poorly defined, inner row of pores round, outer row
slitlike, pairs of pores conjugated. The whole surface of the test is covered with rather con-
spicuous small tubercles which are larger on the lower surface. The apical system is sub-
central, with four large genital pores. The peristome is small, subpentagonal, subcentral;
ambulacral grooves poorly defined, not well preserved on the specimen. The periproct is
small, subcircular to subpentagonal, about one-third the way from the margin to the peristome.

Dimensions.—Length 34 millimeters; width 30 millimeters; height 10 millimeters.

Related forms.—This species is very closely related to ZL. crustuloides, in fact so close that
further collecting may lead to its being made a synonym of the latter species. Its chief dis-
tinguishing features are its greater height and the greater height and thickness of its margin.
These features distinguish it not only from L. crustuloides, but also from the other American
representatives of the genus, from which it differs also in its pronouncedly concave lower surface.

Locality.—Turks Cave, Ala.

Geologie horizon.—Probably Vicksburg formation, lower Oligocene.

Collection.—U. S. National Museum (137202); collected by L. C. Johnson, after whom it is
named.

LAGANUM FLORIDANUM Twitchell, n. sp.

Plate LXXV, figures 3a-d.

Determinative characters —Test small, oval in marginal outline. General form subdiscoidal,
the upper surface very low, almost parallel with the lower surface, with a slightly concave ring
between the slightly tumid petaloidal area and the notably thickened margin. Apex and
apical system slightly excentric anteriorly. Lowersurface flat. Ambulacral petals subelliptical,
very short, extending halfway to the margin, pointed and closed at ends. Petaloidal area notably
smaller than in related forms. Periproct small, circular, about one-third the way from margin
to peristome.

Dimensions.—Length 20 millimeters; width 18 millimeters; height 3 millimeters.

Description.—This new Laganum from Florida has a small test which is almost regularly
oval in marginal outline. The whole form is greatly depressed; subdiscoidal; the upper sur-
face being almost parallel with the lower; the apical region slightly tumid, the tumidity involv-
ing the larger part of the petals; the region around the ends of the petals concave; the margin
notably thickened, slightly more so anteriorly than posteriorly. The lower surface is flat, or
nearly so. The apex is slightly excentric anteriorly, at the summit of the central tumid area,
which rises but very slightly above the height of the margin.

The ambulacral petals are subelliptical, somewhat pointed and closed at the ends; very
short, extending only about halfway to the margin, subequal in length. The poriferous zones are
very narrow, much narrower than the interporiferous areas, the proximal ends poorly defined,
inner row of pores round, outer row slitlike, pairs of pores conjugated. The whole surface of
the test is covered with small tubercles set in deep scrobicules, which are somewhat larger on
the lower surface.

The apical system is slightly excentric anteriorly, comcident with the apex. There are
four large genital pores, the anterior pair being set closer together than the posterior pair.
The poriferous zones can not be seen to come together at their proximal ends, and the perfora-
tions of the radial plates can not be made out.

The peristome is small, slightly excentric anteriorly, subpentagonal. The ambulacral
grooves are inconspicuous and could not be made out on the single specimen studied.

The periproct is small, about half the diameter of the peristome, circular, located about
one-third the way from the margin to the peristome.

Related forms.—L. floridanum is closely related to L. archerensis and to L. crustuloides, but
differs from both in being more regularly oval in marginal outline and in haying a smaller

164 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

petaloidal area. It differs further from L. crustuloides in having a flat under surface, a less
elevated central area, and a concave ring on the upper surface.

Locality — Johnsons Sink, Fla.

Geologic horizon.—Vicksburg group, lower Oligocene.

Collection.—U.S. National Museum (137884).

Laganum patiit Twitchell, n. sp.
Plate LXXYV, figures 4a-d.

Determinative characters—Test small, subpentagonal in marginal outline. General form
subdiscoidal, the upper surface very low, almost parallel with the flat lower surface. Apex
and apical system slightly excentric anteriorly. Ambulacral petals broad, subovate, extending
two-thirds the way to the margin; poriferous zones wide, depressed below the general surface,
thus making the narrow interporiferous areas stand out in relief; madreporite tumid. Peri-
stome probably subcentral. Periproct small, circular, about midway between margin and
peristome.

Dimensions.—Length 16 millimeters; width 15 millimeters; height 4.5 millimeters.

Description.—The type of this handsome little Laganum was found at Archer, Fla., by
W. H. Dall of the United States National Museum, in whose honor the species is named. This
species occurs in association with Laganum archerensis. The test is small in size and subpen-
tagonal in marginal outline. The whole form is greatly depressed, subdiscoidal, the upper
surface being almost parallel with the lower. The margin is notably thickened, slightly less so
at the middle of the posterior end. The lower surface is flat or nearly so. The apex is subcentral
or very slightly excentric anteriorly, though it is but slightly higher than the margin of the test. .
There is no distinct concave ring on the upper surface, but the poriferous zones of the ambu-
lacral petals are slightly depressed below the general surface.

The ambulacral petals are subovate in outline, broad, extending nearly two-thirds the way to
the margin, rounded, blunt, and closed at the ends. The poriferous zones are very wide, as
wide as the interporiferous areas, slightly depressed below the general surface; inner row of
pores round, outer row slitlike, pairs of pores conjugated by very narrow grooves. Inter-
poriferous areas narrow, standing in relief by reason of the depression of the poriferous zones.
The whole surface of the test, including the interporiferous areas, is covered with small tubercles,
set in deep scrobicules, which are larger on the under surface.

The apical system is subcentral or slightly excentric anteriorly, coincident with the apex.
There are four large genital pores of which the anterior pair are nearer together than the
posterior pair. The madreporite is tumid. No other details can be made out.

The under surface is damaged on the single specimen known and the details in regard to
the peristome and ambulacral grooves can not be given, though it is evident that the peristome
was central or subcentral in position.

The periproct is small, circular, about midway between the margin and the peristome.

Related forms.—L. dalli is most closely related to L. grcherensis, differing chiefly in having
no concave ring on the upper surface and in having its periproct farther from its margin.

L. dalli closely resembles Sismondia antillarum Cotteau from the Eocene of the island of
St. Barthelemy but is distinguished by being thicker as a whole, especially on the borders.

Locality —Archer, Fla.

Geologic horizon.—Vicksburg group, lower Oligocene.

Collection —U. 8S. National Museum (164667b).

OLIGOCENE ECHINODERMATA, 165

Order ATELOSTOMATA.
Suborder ASTERNATA.
Family NUCLEOLITID ®.
Genus AMBLYPYGUS Agassiz.
AMBLYPYGUS MERRILLI Twitchell, n. sp.

Plate LXXVI, figures la-d; Plate LX XVII, figures la—b, 2a-b; Plate LX XVIII, figures la—b.

Determinative characters.—Test large to very large, subhemispherical to depressed sub-
conical; circular or subcircular in marginal outline; sides rounded; under surface concave. Apex
central or subcentral. Ampbulacral areas tumid, broad, widest between apex and ambitus;
petals wide open, nearly reaching the ambitus, poriferous zones wide, slightly depressed. Peri-
stome large, irregularly subtriangular, oblique, slightly excentric anteriorly. Periproct very
large, larger than the peristome, subelliptical to subpyriform, longest longitudinally, about
midway between peristome and posterior margin.

Dimensions.—Specimen A (type): Length 115.5 millimeters; width 114 millimeters; height
62 millimeters. Specimen B: Length 73 millimeters; width 69 millimeters; height 40 millimeters.

Description.—This superb Amblypygus, which is one of the largest of American echinoids,

-is the first representative of this rather rare genus to be reported from the United States. The
type specimen was collected by G. P. Merrill, of the United States National Museum, and
the species is therefore named in his honor. The test of the present species is large to very
large, ranging from about 70 millimeters to about 115 millimeters in diameter. It is sub-
hemispherical to depressed subconical in form, the upper surface declining immediately and
equally on all sides from the central or subcentral apex; circular or subcircular in marginal
outline. The margin is rounded and inflated; the under surface concave centrally.

The ambulacral areas are broad, widest about midway between apex and ambitus, thence
narrowing to the apex and peristome; they are slightly tumid, thus forming five tumid ridges
from apex to peristome. The dorsal portions of the areas are subpetaloid, the petals being
long, about reaching the ambitus, wide open at their extremities.. The poriferous zones are
wide, shghtly depressed; both outer and inner rows of pores round, pairs of pores conjugated by
long, narrow grooves.

The interambulacral areas are broad. The surface of the whole test, including the inter-
poriferous areas, 1s covered with numerous small perforate tubercles, with sunken scrobicules.

The apical system is large, central or subcentral. Most of the area of the system is occu-
pied by the large, slightly tumid, granulated madreporite, which appears to be the enlarged
right anterior basal plate. There are four large genital pores, the two anterior being nearer
together than the posterior pair. The radial plates and their perforations can not be discerned
on the specimen. ,

The peristome is very large, irregularly subpyriform, slightly excentric anteriorly. It is
placed in an oblique position, its longest diameter being about 30° to the transverse axis of the
test. :

The periproct is very large, larger than the peristome, subelliptical to subpyriform, situated
about halfway between the peristome and posterior margin, though slightly nearer the peri-
stome; its longer diameter extending longitudinally.

Related forms.—Amblypygus merrilli is not closely related to any other echinoid from the
United States. Of foreign forms it resembles both A. americanus Michelin from the Tertiary of
Jamaica! and A. altus Duncan and Sladen from the Tertiary of India, being intermediate between
them in relative height. The proportion of the mean diameter to the height in A. merrilli is
1:55, whereas in the Jamaican form, according to Duncan and Sladen, it is 1:409 and in the

1 The only good description of A. americanus Michelin is given by Duncan and Sladen in The Tertiary Echinoidea of Kachh and Kattywar,
p. 13, which contains additions to Desor’s descriy ion based on a specimen in the British Museum. So faras the writer has been able to ascertain

the form has never been figured.

166 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Indian 1:0.62 or 1:0.63. A. merrilli also differs from A. altws in haying its peristome more
angular and less oblique and its periproct more pointed posteriorly and farther from the pos-
terior margin. It is nearer A. americanus but is less depressed and has a more subconical upper
surface.

Localities —Kendrick lime quarries near Ocala, Marion County (type), and Clarke, Alachua
County, Fla.

Geologic horizon.—Ocala limestone of Vicksburg group, lower Oligocene.

Collection.—U. S. National Museum (164934, A; 137870, B).

Genus OLIGOPYGUS De Loriol (amended).

Oligopygus was founded in 1887 by De Loriol on the species Oligopygus wetherbyi from
the Tertiary of Florida and so far as known has few representatives outside of the United
States. De Loriol possessed but a few specimens and, although his diagnosis is well drawn,
the large number of specimens studied by the writer (over sixty) has shown the necessity of
amending the description of the genus in a number of important particulars, of which the most
important is noting the fact that it includes forms in which the periproct is inframarginal.

Test moderately large, with thick walls, especially at the ends; usually oval, may be
subcireular, or subpentagonal; sides tumid; under surface slightly concave, with a deep, trans-
verse depression around the peristome; upper surface convex, more or less depressed; apex
central or anteriorly excentric.

Apical system central or subcentral, compact, small, with four perforated basal plates; the
five radial plates small, with minute pores; madreporite central, tumid, extending to or between
the posterior radial plates.

Ambulacral areas broadest at the ambitus, the anterior paired areas curving posteriorly
near the peristome; faintly tumid on the upper surface; dorsal portions varying from sub-
petaloid to petaloid, the petals differing’ slightly in length and more or less open, otherwise
similar. Poriferous zones broad; pores equal or nearly so, pairs united by a long groove.
Beyond the petaloid portions to and beyond the ambitus each plate is perforated at its outer
end by two or three pairs of very small pores.

Peristome central, or subcentral, pentagonal, slightly elongate transversely, at the bottom
of the transverse depression in the under surface; floscelle and jaws wanting. Periproct very
small, circular, opening on the inferior face between the peristome and the posterior margin;
may be inframarginal. Tubercles small, equal, more or less scattered, surrounded by deep
scrobicules and imperforate.

OLIGOPYGUS WETHERBYI De Loriol.
Plate LX XVIII, figures 2a—d, 3a—b.

Oligopygus wetherbyi De Loriol, 1887, Recueil zool. Suisse, vol. 4, No. 3, pp. 396-398, Pl. XVII, figs. 7-8.
Oligopygus wetherbyi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.
Oligopygus wetherbyi Stefanini, 1911, Revista italiana di paleontologia, vol. 17, pt. 2, p. 11.

Determinative characters—Test with thick walls, oval, sides tumid, upper surface depressed
and rather flat on top; under surface with a very deep, long, flaring, transverse depression around
the peristome. Ambulacral areas wide at the ambitus; dorsal portions petaloid, constric-
tions at the ends of the petals somewhat pronounced. Apex and apical system central or
subcentral. Peristome pentagonal, opening at the bottom of the depression in the under sur-
face. Periproct very small, circular, situated about midway between the peristome and pos-
terior margin.

Dimensions.—Specimen A: Length 34 millimeters; width 29 millimeters; height 16 miulli-
meters.

Description—The writer has not had the opportunity of seeing the type of this species,
but De Loriol’s full and clear description and excellent drawings have permitted its ready iden-
tification among the material studied. The test is unusually thick, especially at the ends;

OLIGOCENE ECHINODERMATA. 167

quite regularly oval in marginal outline, though sometimes narrowing anteriorly; margin rounded
and inflated, the anterior end somewhat more so than the posterior, giving that end a bulging
appearance forward. The upper surface is uniformly convex; but depressed and rather flat on
top; under surface slightly concave near the middle and with a very deep, transverse depression
around the peristome. The apex is subcentral, or slightly forward of the center.

The ambulacral areas are wide at the ambitus from which they narrow to the peristome
and apex, but with somewhat pronounced constrictions at the ends of the petaloid portions;
the anterior paired ambulacra curving posteriorly on approaching the peristomial depression;
dorsal portions petaloid, the odd petal being longer than the others, which are equal or nearly
equal in length. ‘The poriferous zones are broad, more than half the width of the interporiferous
area, moderately apart at their extremities; the pores equal or nearly so, small, elliptical; pairs
of pores united by long, narrow, oblique grooves. Beyond the petaloid portions the small
narrow plates of those portions give place to broad plates, each of which to and beyond the
ambitus has two or three pairs of very small round pores placed obliquely near together at
the extreme outer ends of the plates. The interporiferous areas are slightly tumid and stand
out in relief.

The apical system is central or subcentral. The madreporite is large and tumid, central,
pentagonal, the posterior edge being straight and coinciding with those of the posterior radial
plates. There are four genital pores situated at the edge of the madreporite, the posterior pair
being farther apart than the anterior; and there are five small subtriangular radial plates, each
perforated by a very small pore.

The peristome is pentagonal, slightly elongated transversely, opening at the bottom of a very
deep, long, flaring transverse depression in the middle of the under surface. The size and shape
of this depression varies, but its length at the surface is usually about one-half the width, and
its depth about one-half the height of the test. Its anterior and posterior walls slope at
nearly the same angle but in opposite directions toward the peristome forming a broad, deep,
V-shaped concavity.

The periproct is very small and circular, and situated at about midway between the
peristome and the posterior margin.

Numerous small, uniform, imperforate tubercules, surrounded by deep scrobicules, are
scattered irregularly over the entire surface of the test.

Related forms—Oligopygus wetherbyi is most closely related to O. floridanus from which it
can be distinguished by its more depressed form, more petaloid ambulacra, broader poriferous
zones, and its deeper, longer and more open peristomial depression. It also resembles O. halder-
mani, but is readily separated by the more anterior position of its periproct.

From most foreign forms O. wetherbyi can be readily separated by its more profound
depression around the peristome. 0. costulatus (Desor), its nearest ally, according to De Loriol,
has more markedly ridged ambulacra, a more swollen and slightly conical test, and periproct
nearer the peristome. O. ovwm-serpentis (Guppy), from supposedly Eocene deposits of Trini-
dad, is similar but, as noted by Stefanini, differs in having a less profound peristomial cavity
and a more tumid test.

Localities —Near Gainesville, Alachua County (De Loriol) ; 6 miles southwest of Gainesville,
Santa Fe River, Alachua County; and Johnsons Lime Sink, Levy County, Fla.

Geologic horizon—Vicksburg group, lower Oligocene.

Collection—U. S. National Museum (137881a, A; 137881b, B).

OLIGOPYGUS HALDERMANI (Conrad).
Plate LX XVIII, figures 4a-d, 5a-d,

Discoidea haldermani Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 40, Pl. I, fig. 12.
Discoidea haldermani Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.

Discoidea haldermani Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 22.

Discoidea haldermani Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 88.

Determinative characters —Test with thick walls, marginal outline oval to subpentagonal
and slightly undulating; sides tumid; upper surface usually elevated anteriorly and depressed

168 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

posteriorly, sometimes depressed subconical; under surface with a deep and more or less long
and flaring transverse depression around the peristome. Ambulacral areas wide at the ambitus,
dorsal portions petaloid, with a slight constriction at the ends of the petals. Apex forward
of the center. Apical system central or subcentral. Peristome pentagonal, opening at the
bottom of the depression in the under surface. Periproct very small, circular, inframarginal.

Dimensions.—Specimen A: Length 38 millimeters; width 33 millimeters; height 17 milli-
meters. Specimen B: Length 38.5 millimeters; width 31 millimeters; height 17 millimeters.

Description.—lt is thought highly probable that we have here the same species which Conrad
described in 1850 under the name of Discoidea haldermani, as some of the specimens studied
came from near the same place that Conrad’s form did and correspond fairly well with his
figures and description. The type can not be located; and as Conrad did not figure the under
surface of his form there is some doubt regarding the position of the periproct and the presence
of a pronounced peristomial depression. The fact that Conrad assigned his species to the genus
Discoidea, points to an inframarginal position for the periproct. Should Conrad’s type ever be
found, and prove to be different from the present species, then it will be necessary to give a new

name to this Oligopygus.

This species appears to be the most abundant and also the most variable of the genus.
The writer has had the opportunity of studyimg over 35 specimens, including both young
and adult forms, varying in size from three-eighths inch to 14 inches in length. The test is
unusually thick. The marginal outline varies from regularly oval to subpentagonal, the former
being more usual in the smaller and younger, and the latter in the larger and older forms, and is
slightly undulating, which is chiefly due to broad and shallow creases in the middle of the inter-
ambulacral areas. The margin is rounded and inflated, the anterior end usually more so than
the posterior, giving that end a bulging appearance in a forward direction, though at times the
two ends are nearly equally inflated. The upper surface is somewhat convex, but more or less
depressed and flat on top, sometimes more elevated anteriorly than posteriorly, sometimes
depressed subconical in form; under surface tumid, but more or less flattened, and with a deep
transverse depression around the peristome. The apex is subcentral or excentric anteriorly.

The ambulacral areas are wide at the ambitus, from which they gradually narrow to the
peristome and apex, with a slight constriction at the ends of the petaloid portions; the anterior
paired ambulacra curying posteriorly on approaching the peristomial depression; dorsal por-
tions varying from subpetaloid to slightly petaloid, the odd petal being slightly longer than the
others, which are equal or nearly equal in length. Poriferous zones rather broad, gradually
diverging toward their extremities, then converging slightly but still wide apart at the ends;
outer edges slightly depressed, forming ten more or less well defined linear grooves on the upper
surface of the test; the pores equal or nearly so, small, elliptical, and conjugate. There are also
several pairs of very small pores near the outer end of each plate from the ends of the petals
to beyond the ambitus. The interporiferous areas are slightly tumid.

The apical system is central, or slightly excentric anteriorly. The madreporite is large,
tumid and subcircular, and extends to and between the posterior radial plates. There are
four genital pores, situated at the edge of the madreporite, the posterior pair being farther apart
than the anterior; and there are five smell radial plates, each perforated by a minute pore.

The peristome is pentagonal and opens at the bottom of arather deep transverse depression in
the middle of the under surface. This depression varies in length from one-third to one-half the
width of the test, and in depth from one-fourth to one-third the height of the test; and is more
or Jess open and flaring in form.

The periproct is very small, uniform, circular, and inframarginal.

Numerous small, uniform, imperforate tubercles, surrounded by deep scrobicules, are scat-
tered irregularly over the entire surface of the test.

Related forms.—Oligopygus haldermani resembles O. wetherbyi.and O. floridanus but is
readily separated from both by the inframarginal position of its periproct. Of foreign forms,
O. ovum-serpentis (Guppy), from supposedly Eocene deposits of Trinidad, is closely allied but.
has its periproct farther from the margin.

OLIGOCENE ECHINODERMATA, 169

Localities—Richards Quarry, Ocala, Marion County, and Johnsons Lime Sink, Levy
County, Fla.; Flint River near Bainbridge, Baker County, Ga. Conrad’s specimen came from
a well near Bainbridge, Ga.

Geologic horizon.—Vicksburg group, lower Oligocene. The specimens from Ocala are from
the Ocala limestone.

Collections.—U. S. National Museum (112506, A; 164661, B); Wagner Free Institute of
Science.

OLIGOPYGUS FLORIDANUS Twitchell, n. sp.

Plate LX XIX, figures la-f.

Determinative characters.—Test with thick walls, oval, narrowing anteriorly; sides tumid;
upper surface convex, elevated anteriorly, slightly depressed posteriorly; under surface with a
deep, relatively short and narrow transverse depression around the peristome. Ambulacral
areas wide at the ambitus, from which they gradually narrow to the peristome and apex; dorsal
portions subpetaloid; petals wide open. Apex excentric anteriorly; apical system central or
slightly excentric anteriorly. Peristome pentagonal, opening at the bottom of the depression
in the under surface. Periproct very small, circular, situated about midway between the peri-
stome and posterior margin.

Dimensions.—Length 37 millimeters; width 31 millimeters; height 19 millimeters. The
dimensions of another specimen were, length 48 millimeters; width 42 millimeters; height 26
millimeters.

Description.—This new species of Oligopygus is rather rare, only three specimens being
known to the writer. De Loriol may have possessed a specimen, for some of the characters he
ascribes to O. wetherbyi apply more correctly to this species. The test is usually thick, especially
at the ends; oval on marginal outline, though somewhat narrower toward the anterior end;
margin rounded and inflated, the anterior end more so than the posterior, giving that end a
bulging appearance in a forward direction. The upper surface is convex, somewhat elevated
forward of the center, declining gradually toward the posterior end and sloping somewhat
steeply on the sides; under surface tumid but slightly concave transversely near the middle,
with a deep transverse depression around the peristome. The apex is forward of the center.

The ambulacral areas are wide at the ambitus, from which they gradually narrow to the
peristome and apex, there being hardly any constriction at the ends of the petaloid portions,
the anterior paired ambulacra curving posteriorly on approaching the peristomial depression;
dorsal portions subpetaloid, the odd petal beg somewhat longer than the posterior pair, which
are somewhat longer than the anterior pair. The poriferous zones are narrow, nearly straight,
and gradually diverge from their origin at the apex to their extremities, which are wide apart;
pores small, oval, equal and conjugate. There are also several pairs of very small pores near
the outer end of each plate from the ends of the petals to beyond the ambitus _ The interporif-
erous areas are slightly tumid, standing out in relief in the unweathered specimen, so as to form
five straight radial ridges from apex to ambitus.

The apical system is central or somewhat excentric anteriorly. The madreporite is large
and tumid, central, shield shaped; the posterior end being pointed and extending between the
posterior radial plates. There are four genital pores, situated at the edge of the madreporite, the
posterior pair being farther apart than the anterior; and there are five small radial plates, each
perforated by a very small pore.

The peristome is pentagonal and opens at the bottom of a deep, transverse depression in
the middle of the under surface. This depression is relatively short and narrow; its length at the
surface being about one-third the width and its depth about one-third the height of the test. Its
anterior wall is nearly vertical or even inclined slightly toward the anterior end but at a much
steeper angle than the posterior wall, thus formmg a deep, narrow, anteriorly projecting
concavity.

The periproct is very small and circular; and situated about midway between the peristome
and the posterior margin.

170 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Numerous small, uniform, imperforate tubercles, surrounded by deep scrobicules, are
scattered irregularly over the entire surface of the test.

Related forms.—Oligopygus floridanus is closely related to O. wetherbyi, from which it can be
separated by its higher and less flattened upper surface, its subpetaloid ambulacra, narrower
poriferous zones, and its shorter, less flarmg, anteriorly projecting peristomial depression. It
also resembles Qligopygus haldermani but can at once be distinguished by the more anterior
position of its periproct.

Of foreign forms, O. ovum-serpentis (Guppy), from supposedly Eocene deposits of Trinidad,
is closely allied; but its periproct is nearer the margin and its peristomial depression less
pronounced.

Tocality.—Nigger Sink, 2 miles south of Gainesville, Alachua County, Fla.

Geologic horizon.—Vicksburg group, lower Oligocene.

Collection.—U. S. National Museum (164660).

Family CASSIDULID®.
Genus CASSIDULUS Lamarck.
CassIpULUs (PYGORHYNCHUS) GEORGIENSIS Twitchell, n. sp.
Plate LX XIX, figures 2a-d.

Determinative characters.—Test broadly oval, upper surface convex, moderately elevated,
sides and anterior end rounded; posterior end obliquely truncated, under surface flat, curving
upward slightiy posteriorly to meet the posterior truncation in an angular margin; apex sub-
central. Ambulacral areas narrow; petals narrow, nearly closing, the posterior pair having the
inner poriferous zone of each petal shorter than the outer zone. Apical system excentric ante-
riorly. Peristome excentric anteriorly, pentagonal, transversely elongate, with a floscelle.
Periproct small, subrhomboidal, transverse; located at the top of the rather high posterior trun-
cation, beneath a rounded, somewhat protruding expansion of the test.

Dimensions.—Length 26 millimeters; width 22.5 millimeters; height 15 millimeters. An-
other specimen, of nearer average size gave, length 35 millimeters; width 32 millimeters; height
20 millimeters.

Description.—This new Cassidulus, which is rather rare, only three specimens being reported,
has a test which is broadly oval in marginal outline, more obtusely rounded posteriorly than
anteriorly, and obliquely truncated at the posterior end. The upper surface is regularly convex,
moderately elevated, in the form of a low, rounded ridge above the periproct, sides and anterior
end rounded and inflated; under surface flat, curving upward slightly posteriorly to meet the
oblique posterior truncation in an angular margin, the angle formed being about 75°. The apex
is subcentral.

The ambulacral areas are narrow, dorsal portions petaloid, the petals narrow, partly open
at the ends, the posterior petals longer than the others, which are nearly equal in length. The
poriferous zones are narrow; the inner zone of each of the posterior pair of petals shorter than the
outer zone; outer row of pores slitlike, mer row round; pairs of pores conjugate.

The surface of the test is closely set with numerous small tubercles which increase in size
on the under surface except along a rather wide median band which is free from tubercles and
dotted with numerous small pits. The tubercles are set in serobicules which are shallow and
irregularly shaped on the upper surface; but become larger, deeper and more regular in form on
the under surface.

The apical system is excentric anteriorly. The only details which can be made out are the
existence of four genital pores, of which the anterior pair are nearer together than the posterior,
and five small perforated radial plates.

The peristome is excentric anteriorly, immediately beneath the apical system, pentagonal,
transversely elongate, with a floscelle of which the phyllodes are rather well defined and the bour-
relets are large and prominent.

OLIGOCENE ECHINODERMATA, iL7(al

The periproct is relatively small, about 3 or 4 millimeters in length, subelliptical to sub-
rhomboidal, transverse; and located relatively high up on the posterior surface, at the top of the
rather high posterior truncation, beneath a rounded, transverse, somewhat protruding expansion
of the test.

Related forms.—Cassidulus georgiensis is readily separated from the other representatives of
the genus from American deposits. In some features it resembles Cassidulus carolinensis, but
it can be distinguished by its flatter under surface, more obtusely rounded and more angular pos-
terior margin, higher and more oblique posterior truncation, and smaller periproct. Of foreign
forms OC. georgiensis resembles some forms of Pygorhynchus grignonensis (Defrance) Agassiz from
the Eocene of France, but can be separated by its more oblique posterior truncation, more
angular posterior margin, and higher placed periproct.

Localities.—Flint River, near Bainbridge, Baker County, and 24 miles north of Cuthbert,
Ga.; Alabama (exact location unknown).

Geologic horizon.—Vicksburg formation, lower Oligocene. Possibly also Jackson formation,
upper Eocene. The matrix is a yellow mass of foraminiferal remains.

Collections.—U. S. National Museum (164547) ; Yale University.

CassipuLUS (PyGorHyNcHUs) GouLpiIr (Bouvé).

Plate LXXIX, figures 3a-d; Plate LX-XX, figures lat, 2a-d.
Pygorhynchus gouldii Bouvé, 1846, Boston Soc. Nat. History Proc., vol. 2, p. 192.
Pygorhynchus gouldii Bouvé, 1847, Am. Jour. Sci, 2d ser., vol. 3, p. 437.
Pygorhynchus gouldii Bouvé, 1847, Annals and Mag. Nat. History, Ist ser., vol. 20, p. 142.
Nucleolites mortoni Conrad, 1850, Acad. Nat. Sci. Philadelphia Jour., 2d ser., vol. 2, p. 40, Pl. I, fig. 11.
Pygorhynchus gouldii Bouvé, 1851, Boston Soc. Nat. History Proc., vol. 4, pp. 2-4, two figures in text.
Pygorhynchus gouldii Desor, 1858, Synopsis des échinides fossiles, p. 299.
Ravenelia gouldii McCrady, 1859, Elliott Soc. Nat. History Charleston Proc., vol. 1, pp. 282, 283, no figure.
Pygorhynchus gouldii Dujardin and Hupé, 1862, Histoire nat. zoophytes échinodermes, p. 585.
Pygorhynchus gouldii Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.
Pygorhynchus gouldit Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 22.
Pygorhynchus gouldii Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 91.
Pygorhynchus gouldii Cotteau, 1888, Paléontologie francaise, Echinides éocénes, vol. 1, p. 550.
Pygrohynchus gouldit Clark, 1891, Johns Hopkins Univ. Circ., vol. 10, No. 87, p. 77.
Nucleolites mortoni Boyle, 1893, U. S. Geol. Survey Bull. 102, p. 200.
Pygorhynchus gouldit Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 696.

Determinative characters.—Test irregularly subconical, broadly ovate, broadest back of
middle; variable in height; margin flat along the sides, angular at the ends, sharply angular under
periproct; upper surface elevated anteriorly, more or less obliquely flattened and depressed
posteriorly, under surface slightly concave longitudinally. Apex excentric anteriorly. Ambu-
lacral areas broad in petaloidal region, narrow beyond; petals long, rather sharply pointed at
both ends, almost closing. Apical system excentric anteriorly or subcentral. Peristome trans-
versely elongate, excentric anteriorly, more so than the apical system, with floscelle. Periproct
elliptical, transverse, supramarginal, at the top of a shallow groove, and beneath an overhanging
expansion of the test.

Dimensions.—Specimen A (type): Leagth 52 millimeters; width 49 millimeters; height 25
millimeters. Specimen B: Length 35 millimeters; width 33 millimeters; height 18 millimeters.
Specimen C (unusually high): Length 38 millimeters; width 36 millimeters; height 24 milli-
meters.

Description.—The species was reported and an excellent description given as early as 1846
by T. T. Bouvé of Boston, whose type specimen the writer has had the privilege of studying.
The form, which though one of the best known in the literature was formerly considered rather
rare, has been shown by recent collections made by the members of the United States Geological
Survey and others to be one of the most abundant of American Cenozoic echinoids. It is
especially abundant in Florida, where it has been found at many localities. The species is very
variable, its extreme specimens differing so much in a number of details that they might be

172 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

regarded as different species were it not for the intermediate forms found in the large amount
of available material. Many of the specimens are only well-preserved casts.

The test is irregularly subconical in form; the marginal outline broadly ovate, broadest
back of the middle; margin thick and vertically flattened along the anteriorly converging side
portions, more or less angular at the ends, sharply angular beneath the periproct. The upper
surface varies from rather low and depressed to moderately high. It is irregularly subconical;
the apex being more or less excentric anteriorly, the side and anterior surfaces sloping nearly
equally and somewhat steeply though with a more or less rounded contour, and the posterior
surface sloping less steeply and being more or less flattened, except for a slight tumidity above
the periproct. The under surface is concave along the longitudinal median area. The apex is
excentric anteriorly, sometimes coincident with, sometimes anterior to the apical system.

The ambulacral areas are narrow at the ambitus, dorsal portions petaloid; petals rather
wide, long, the posterior pair slightly longer than the anterior pair which are slightly longer than
the odd petal, rather sharply pointed at both ends, almost closing at their extremities. The
poriferous zones are rather wide, slightly depressed; pores subequal, outer row oval, inner row
round; pairs of pores conjugate; interporiferous areas slightly tumid.

The surface of the test is closely set with small scrobiculate tubercles which increase in size
on the under surface except along a rather narrow pitted median area.

The apical system is excentric anteriorly in most specimens, but is subcentral in some. In
most it is coincident with the apex but in some it is slightly back of it. Because of the poor
character of the specimens, the details can rarely be made out. There are four perforated basal
plates, the anterior genital pores being nearer together than the posterior, and five small perfo-
rated radial plates.

The peristome is pentagonal, somewhat elongate transversely, excentric anteriorly, more so
than the apical system, being about three-eighths the length of the test from the anterior margin; |
and apparently more fixed in its relative position than the apical system. It is surrounded by a
well-defined floscelle with rather prominent bourrelets. On the casts the phyllodes form prom-
inent radial ridges around the peristome.

The periproct is moderately large, elliptical, transverse, supramar ginal, rather low andl near
the posterior end, beneath a low, rounded, transverse expansion of the test. Beneath the peri-
proct there is a depression which sondlens the margin at this point thinner or more sharply angular
than it is elsewhere. :

Related forms.— Among American forms Cassidulus gouldw is most nearly related to C. ala-
bamensis but can readily be distinguished by its smaller size, less subquadrate form, and more
steeply sloping sides. It does not appear to very closely resemble any foreign forms.

Localities.—Baker County (type); Laurenden Creek; Hawkinsville; A. HE. Belcher’s well,
Decatur County; 32 miles south of Macon, on Georgia & “Florida Risivoad: Ellayville; 24 cates
north of Cuthbert, Ga. Two miles south of Gainesville; 6 miles southwest aft Lake City; Santa
Fe River, Alachua County, Pembertons Ferry, iWaehiocooenes River 4 and 5 miles west of Live
Oak; deep wells at Padlock, 7 miles south of Live Oak; Sulphur Springs Ferry, Suwannee
County, Fla.

Geologie horizon.—Vicksburg group, lower Oligocene, possibly Eocene also. Bouvé said
his form was from the “Millstone erit’’ and Conrad said his was from the ‘‘Buhrstone”’; con-
sequently the species has hitherto hee regarded as Hocene; but nearly all of the large number of
specimens studied by the writer came from Oligocene deposits.

Collections.—Boston Society of Natural Asko (1756, A); U.S. National Museum (137904,
B; 137904a, C); Academy of Natural Sciences of Piha daha: Wagner Free Institute of
Science.

CassIpULUS (PYGORHYNCHUS) ALABAMENSIS Twitchell, n. sp.

Plate LX XX, figures 3a-d.

Determinative characters.—Test large, subquadrate, depressed; upper surface convex,
declining from apex nearly equally on all sides; under surface concave longitudinally. Apex
subcentral, slightly to the rear of the anteriorly eccentric apical system. Ambulacral areas

OLIGOCENE ECHINODERMATA. 173

broad in petaloidal portion, narrow beyond; petals long, subequal in length, almost closing.
Peristome rather large, pentagonal, transversely elongate, excentrie anteriorly, more so than the
apical system, with a floscelle. Periproct rather large, elliptical, transverse, supramarginal, at
the top of a broad shallow groove and beneath an overhanging expansion of the test.

Dimensions.—Length 69 millimeters; width 63 millimeters; height 29 millimeters.

Deseription.—This large Cassidulus, the largest representative of the genus from American
Cenozoic deposits, is very rare, only a few specimens having been discovered. The test is
moderate to large in size, moundlike in form, depressed, subquadrate in marginal outline; margin
thick, somewhat flattened on the sides, more angular at the ends, sharply angular beneath the
periproct. The upper surface is convex, and declines gently from the apex nearly equally on
all sides, though the side outlines tend to be straight while the end outlines tend to be curving;
ashght tumidity exists along the medial Ime above the periproct. The undersurface is decidedly
concave along a broad, longitudinal median area. The apex is nearly central, being but slightly
excentric anteriorly.

The ambulacral areas are narrow at the ambitus, dorsal portions petaloid; petals rather
wide, long, of nearly equal length, almost closing at their extremities. The poriferous zones are
rather wide, slightly depressed; pores subequal, outer row oval, inner row round; pairs of pores
conjugate; interporiferous areas slightly tumid.

The surface of the test is closely set with small scrobiculate tubercles which increase in size
on the under surface except along a rather narrow median pitted area.

The apical system is large and slightly excentric anteriorly, somewhat anterior to the apex.
There are four genital pores, the anterior pair being nearer together than the posterior, and there
are five minute pores perforating the radial plates.

The peristome is rather large, pentagonal, transversely elongate, excentric anteriorly, more
so than the apical system, being about three-eighths the length of the test from the anterior
margin. It is surrounded by a large, well-defined floscelle, with prominent bourrelets.

The periproct is rather large, elliptical, transverse, supramarginal, rather high up, at the
top of a broad shallow groove and beneath a rounded overhanging expansion of the test.

Related forms.—Cassidulus alabamensis is closely related to C. gouldii, from which it is readily
separated by its greater size and its relatively low almost regularly convex upper surface. It
does not appear to be closely related to any foreign form.

Localities —Natural Bridge, St. Stephens, Ala.; A. E. Belcher’s well, Decatur County, Ga.

Geologic horizon.—St. Stephens limestone (upper part), lower Oligocene.

Collection.—Johns Hopkins University (type).

Genus ECHINOLAMPAS Gray.
ECHINOLAMPAS ALDRICHI Twitchell, n. sp.
Plate LX X XI, figures la-d, 2.

Determinative characters.—Test large, subcircular; margin rounded; upper surface depressed
subconical, sloping more steeply anteriorly than posteriorly; under surface concave, posterior
end slightly rostrate; apex forward of the center. Ambulacral areas rather narrow, dorsal por-
tions petaloid; petals long, open at the ends, poriferous zones of some petals unequal in length,
interporiferous areas tumid. Apical system excentric anteriorly. Peristome large, excentric
anteriorly, slightly less so than apical system, pentagonal, transversely elongate, surrounded by a
floscelle with feeble phyllodes and bourrelets. Periproct large, elliptical, transverse, infra-
marginal.

Dimensions.—Specimen A (type, smaller than the average): Length 56 millimeters; width
54 millimeters; height 26 millimeters. Largest specimen: Length 80 millimeters; width 75
millimeters; height 37 millimeters.

Description.—Ot this fine Echinolampas the only specimens so far reported belong to T. H.
Aldrich, of Birmingham, Ala., in whose honor the species is named. The.test is large (ranging

1The Aldrich collection is now owned by the Johns Hopkins University.

39800°—15——12

174 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

from 2 to 3 inches in diameter) and about half as high as broad. The marginal outline is broadly
oval to subcircular; sometimes, especially in the larger and older forms, slightly broader pos-
teriorly than anteriorly and broadly V-shaped at the posterior end; margin tumid and rounded.
The upper surface is depressed subconical, though at times approaching a depressed subhemi-
spherical contour, sloping more steeply anteriorly and on the sides than posteriorly; under sur-
face concave, though slightly tumid around the margin except along the posterior ambulacral
areas where there are broad and very shallow depressions which give the posterior end of the
test a slightly rostrate appearance. The apex is forward of the center, about two-fifths of the
length of the test from the anterior end, coincident with the apical system.

The ambulacral areas are rather narrow, dorsal portions petaloid; petals long, rather narrow,
open at their extremities, the posterior pair slightly longer than the anterior pair which are
slightly longer than the odd petal; interportferous areas tumid. The poriferous zones are
rather narrow, slightly depressed, the inner zone of each of the posterior petals and the anterior
zone of each of the anterior paired petals being slightly straighter and shorter than its fellow, |
the differences being the more pronounced in the anterior pair; outer pores slitlike, ner pores
round, pairs of pores conjugate.

The whole surface of the test is closely set with very small, uniform tubercles in sunken
scrobicules.

The apical system is excentric anteriorly. There are four perforated basal plates, the
anterior pair of genital pores being nearer together than the posterior, and five small perforated
radial plates. The madreporite is large, occupying the larger part of the system, and extending
back between the posterior radial plates.

The peristome is rather large, excentric anteriorly, slightly less so than the apical system,
pentagonal, transversely elongate, at the deepest portion of the concave under surface, and
surrounded by a floscelle with feeble, straight phyllodes and low, broad, tumid bourrelets.

The periproct is rather large, elliptical, the posterior side slightly less convex than the
anterior, transverse, inframarginal, very close to the posterior margin.

Related forms.—Echinolampas aldrichi is quite unlike Echinolampas appendiculatus, the
only other representative of the genus found in the Cenozoic deposits of the United States. Of
foreign forms it is very similar to Echinolampas affinis (Goldfuss) Agassiz, which occurs in the
Eocene of Belgium and France, but it is to be distinguished by its more anteriorly excentric
apex and the somewhat unequally excentric positions of its apical system and peristome. It
also resembles Echinolampas insignis Duncan and Sladen from the Nummulitic series of the
Tertiary of India, from which, however, it differs in being smaller, less elevated, and having its
apex more excentric anteriorly.

Localities. —Gainestown, and Choctaw Bluff, Alabama River, Alabama; Mississippi (exact
locality unknown). .

Geologic horizon.—St. Stephens limestone, Alabama; Vicksburg limestone, Mississippi;
lower Oligocene.

Collection.—Johns Hopkins University (T 1099, A).

Suborder STERNATA.

Family SPATANGID®.
Genus AGASSIZIA Valentin.
AGASSIZIA CONRADI (Bouyé).

Plate LX XX1I, figures 3a-d.

Hemiaster conradi Bouvé, 1851, Boston Soc. Nat. Hist. Proc., vol. 4, p. 3, figures in text.
Hemiaster conradi Desor, 1858, Synopsis échinodermes fossiles, p. 373.

Hemiaster conradi Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 75.

Hemiaster conradi Conrad, 1866, Check list, Eocene and Oligocene.

Ditremaster conradi Cotteau, 1887, Paléontologie frangaise, Echinides éocénes, vol. 1, p. 427.
Agassizia floridana De Loriol, 1887, Recueil zool. Suisse, vol. 4, pp. 398-401, Pl. XVII, fig. 9.
Opissaster conradi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 700.

Agassizia floridana Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

OLIGOCENE ECHINODERMATA. 175

Determinative characters.—Test small, ovoid, upper surface high. Apical system very
excentric posteriorly. Ambulacra narrow, anterior indistinct in shallow depression and with
short petals in shallow groove. Surface covered with very small tubercles. Peripetalous
fasciole indistinct. aniston large. Periproct high on posterior truncation.

Dimensions.—Length 18 =aflllanettense width 16 millimeters; height 14 millimeters.

Description.—This small delicate form is different from any other Tertiary species. The
test is ovoid, much elevated, the high apex giving a subconical appearance to the upper surface.
The apex is very excentric posteriorly and the upper surface slopes from it in all directions.
The under surface is convex except for the peristomial depression.

The ambulacra are narrow, the anterior hardly distinguishable on a nearly flush surface
which shows a slight depression. The paired ambulacra have short petals in shallow grooves,
the posterolateral pair being not half the length of the anterolateral.

The interambulacra are broad, the upper portions of the paired areas near the apex being
gibbous and terminating in short, narrow ridges. The posterior interambulacrum has a pro-
nounced truncation, which slopes inward so that the periproct is not visible from above but is
from below.

The fascioles are very narrow and only traces of them can be seen here and there.

The peristome is large and bilabial. The periproct is quite large, transverse oval, slightly
overhung by-the projecting interambulacrum.

The apical system consists of four genital plates, the perforatioas of which are near together.

Related forms.—This species is easily distinguished from other species of this genus by its
much elevated upper surface, slightly conical at the apex, and its very excentric apex posteriorly.
The sharp truncation of the posterior surface is very characteristic. These and other characters
distinguish it from A. excentrica, which still lives in the Caribbean Sea and near the coasts of
Florida and also from A. clevei of the Miocene of the island of St. Barthelemy.

Localities—Georgia (Bouvé); near Bainbridge (figured specimen) and 34 miles south of
Sasser oa Dawson-Albany public road, Georgia; near Gainesville, Fla.

Geologic horizon.—Lower Oligocene.

Collection. —U. S. National Museum (164744); Geological Survey of Georgia.

Genus SCHIZASTER Agassiz.

SCHIZASTER FLORIDANUS Clark, n. sp.

Plate LX XXII, figures la-c.

Determinative characters —Test rather large, cordiform, high posterior upper surface, nearly
flat lower surface. Ampbulacra in broad, deep grooves, the petals of the paired ambulacra being
very pronounced. Posterior truncation prominent with high periproct. Peristome near anterior
margin.

Dimensions. Length 50 millimeters; width 24.5 millimeters; height 30 millimeters.

Description.—The species is represented only by forms in which the test has been replaced
- by silica, obliterating some of the features but admirably preserving others.

The test is of rather large size, cordiform, with a sloping upper surface which extends up
from the depressed anterior margin to the much elevated posterior margin. The lower surface
is nearly flat.

The ambulacra are broad, the anterior ambulacrum being in a broad deep groove mike
passes over the anterior margin. The paired ambulacra have broad deep petals, the antero-
lateral pair being about one and one-half times as long as the posterolateral.

The interambulacra are wide and are slightly gibbous near the apex. The posterior area
has a sharp ridge reaching to the posterior margin. A pronounced truncation characterizes this
area, the slope being actually inward and the periproct being found high on the surface. The
peristome is large and near the anterior margin.

Locality —Jobhnsons Sink, Levy County, Fla.

Geologic horizon.—Vicksburg group, lower Oligocene.

Oollection.—U. S. National Museum (164655).

176 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

SCHIZASTER AMERICANA Clark, n. sp.
Plate LXXXI, figures fad.

Determinative characters —Test medium size, subpentagonal, as wide as long, upper surface
elevated posteriorly. Ambulacra narrow, the anterior deeply sunken in deep groove; the paired
ambulacra with short petals, the posterior about one-half the length of the anterior. Interam-
bulacra broad, prominent. Peristome near anterior margin, in well-marked depression. Peri-
proct high on truncated posterior margin, peripetalous and lateral fascioles clearly marked.

Dimensions.—Length 39 millimeters; width 39 millimeters; height 25 millimeters.

Description.—The species has a test of medium size, rather tall, subpentagonal, as wide as
long, sloping up from the anterior margin to the nearly central apical system, beyond which a
sharp rise continues toward the posterior margin, its highest point beg about midway.

The ambulacra are narrow, the anterior one situated in a deep, moderately wide groove that
indents the anterior margin. The paired ambulacra have deep short petals, the anterolateral
being about twice as long as the posterolateral.

The interambulacra are broad and somewhat gibbous on the sides. The posterior inter-
ambulacrum is much elevated and rather narrow. The surface is covered with numerous small
but clearly distinct tubercles with small granules between them. The peripetalous and lateral
fasciole can be readily traced.

The apical system is small and nearly central in position. The peristome is near the anterior
margin in a well-marked depression. The periproct is high on the truncated posterior margin.

Localities —Y ost limekiln near Brandon station, Rankin County (type), and Clarke County,
Miss.; 5 miles south of Ellaville, on Ellayville-Americus public road, Georgia.

Geologic horizon.—Vicksburg formation, lower Oligocene.

Collection —U. S. National Museum (165695); Geological Survey of Georgia.

EupaTagus FLorIDANUS Clark, n. sp.

Plate LX XXII, figures gad; Plate LX XXIII, figures la-c, 2a-d.

Determinative characters.—Testlarge, elongate, subcordiform, depressed, sloping from anterior
margin to point half way from apical system to posterior truncation. Ambulacra nearly flush,
poriferous zones somewhat sunken, paired ambulacra with long petals. Interambulacra with
large perforate and crenulate tubercles irregularly scattered over surface. Fascioles distinct.
Peristome small. Periproct large.

Dimensions.—Specimen K: Length 65 millimeters; width 56.5 millimeters; height 31.5
millimeters. Specimen B: Length 67 millimeters; width 56 millimeters; height 30 millimeters.
Specimen C: Length 49 millimeters; width 39.5 millimeters: height 23 millimeters.

Description.—A number of specimens of this striking form have been found in the Oligocene
of Florida. The test is large, elongate, subcordiform, oad depressed. The upper surface slopes
from the low anterior margin gr adually to the high sostienilon apex which is situated about half-
way from the apical system to the beginning of the posterior truncation. The lower surface is
nearly flat.

The ambulacra are wide nearly flush and the poriferous zones somewhat sunken. The paired
ambulacra have long, closed petals the posterolateral longer than the anterolateral. The pore
openings of the petaloidal portions are small and round, ine pore pairs connected by deep furrows.

The interambulacra consist of large plates corered somewhat irrecularly with large per-
forate and crenulate tubercles, the greater number occurring in more or less horizontal rows along
the upper part of the plates above the ambitus.

The apical system isanterior to the center of the upper surface, is small and nearly flush.

The fascioles are distinct here and there. The peristome is small and semicircular. The
periproct is large, occupying much of the truncated surface.

Related forms.—This species has many points of similarity to Z. clevei Cotteau of St. Bar-
thelemy Island, although it differs in some minor particulars. It may prove to be the same
species.

OLIGOCENE ECHINODERMATA. 177

Locality——Johnsons Sink (type specimen A), Levy County (type specimens B and C), Fla.

Geologic horizon.—Vicksburg group, lower Oligocene.

Collections.—U. 8. National Museum (137881, A); Wagner Free Institute of Science (B);
Museum of Comparative Zoology.

Class HOLOTHURIOIDEA.

Order PARACTINOPODA.
Family SYNAPTID#.
Genus CHIRODOTA Eschscholtz.

CHIRODOTA sp.

Chirodota sp. Cunningham, 1895, Am. Micr. Jour., vol. 16, pp. 193-196, and figs. 1 and 2.

Description.—Small holothurian plates are figured by Cunningham and referred to the genus
Chirodota. No material has-been accessible for the present investigation.

Locality.—Near Red Bluff station, Chickasawhay River, Clarke County, Miss.

Geologic horizon.—Vicksburg limestone, lower Oligocene.

Collection.—K. M. Cunningham, Mobile, Ala.

Genus SYNAPTA Eschscholtz.

SYNAPTA sp.

Synapta sp. Cunningham, 1895, Am. Micr. Jour., vol. 16, pp. 193-196, and figs. 3-6.

Deseription.—Fragments of small plates and a spicule are figured by Cunningham and
referred to the genus Synapta. No material has been accessible for the present investigation.

Locality.—Near Red Bluff station, Chickasawhay River, Clarke County, Miss.

Geologic horizon.—Vicksburg limestone, lower Oligocene.

Collection.—K. M. Cunningham, Mcbile, Ala.

MIOCENE ECHINODERMATA.
Class STELLEROIDEA.

Subclass ASTEROIDEA.
Order CRYPTOZONIA.
Family ASTERIIDA.
Genus ASTERIAS Linné.
ASTERIAS REMONDII Gabb.

Asterias remondii Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, pp. 37, 38, Pl. XIII, fig. 69.
Asterias remondi Cooper, 1888, State Mineralogist California Seventh Ann. Rept., p. 270.
Asterias remondi Weaver, 1909, Uniy. California Dept. Geology Pub., vol. 5, No. 16, p. 261.

Description.—Since no material representing this species has been accessible for study the
description of Gabb is given verbatim:

Animal large, robust, five rayed; rays more than twice as long as the diameter of the disk, thick on the margin.
Upper surface covered by short, club-shaped spines, narrow toward the base, and bluntly rounded above; on the sides
these same spines are more closely placed, and on the undersurface they are so close that they are in contact; ambu-
lacree broad, bearing numerous small, very slender spines.

Locality.—Star Fish Point, Martinez, Contra Costa County, Cal. (Cooper), San Pablo Bay,
Cal. (Weaver).

Geologic horizon.—San Pablo formation, upper Miocene.

Collection.—Unknown.

Subclass OPHIUROIDEA.
Order ZYGOPHIUR.
Family OPHIODERMATID,
Genus OPHIODERMA Miiller and Trosch.
OPHIODERMA (%) sp.
Plate LXXXIV, figure 1.
Ophioderma ? sp. Clark, 1904, Maryland Geol. Survey, Miocene, p. 433, Pl. CXX, fig. 3.
Deseription.—Fragments of the arms of an Ophiurian occur in the indurated ledge just above
sea level along St. Marys River. It is impossible to determine the relations of the form with
accuracy, but it is probably an Ophioderma. The fragments were found in the interior of the
shells of large gastropods.
Locality.—St. Marys River, Md.
Geologic horizon.—St. Marys formation, middle Miocene.
Collection.—Johns Hopkins University (T 1000).
Family AMPHIURID®.
Genus, AMPHIURA Forbes.
AMPHIURA SANCT&ZcCRUCIS Arnold.
Plate LX XXIV, figures 2 and 3.
Amphiura sanctzxcrucis Arnold, 1903, U. S. Nat. Mus. Proc., vol. 34, pp. 403-406, Pl. X1, figs. 1, 2.
Description.—Arnold describes the species as follows:

Disk attaining a diameter of 13 millimeters, delicate, covered with small naked overlapping scales. Arms five,
long, slender, even or tapering very slightly and more or less flattened. Arm spines moderately short and sharp
178

MIOCENE ECHINODERMATA. 179

pointed, approximately equal in length to the width of the dorsal median plates. Under arm plates simple, breadth
about 1} length; lower arm plates deeply grooved in the median line.

Disk pentagonal in outline, the arms passing out from the sides rather than from the angles, this being due to the
spreading of the disk upon compression by the containing fine clayey sediments; whole dorsal surface of disk covered
with overlapping scales, which, in the cast serving as the type, are minutely shallowly punctuate corresponding to
numerous microscopic protuberances in the original animal. Radial shields moderately large, of a short, pear-seed
shape, pointed within, outer edge sharply rounded, inner edges nearly straight and separated by five prominently
overlapping scales (the continuation of the upper arm scales, but shorter than the latter) which narrow rapidly toward
the points of the shields. Between the radial shields of adjacent arms are about seven rows of small overlapping
plates, the middle row apparently much larger than the others. The specimen exhibiting the ventral side is
so much crushed that its characteristics are unrecognizable. Upper arm plates simple, small, breadth about 13
length, slightly narrowed within, broader without, straight front, back, and sides. Side plates small, triangular,
with sharp cornered, beveled edges. Underarm plates quite similar to upper, except deeply medially longitudinally
grooved. Spines at least four to a segment; about 1} times length of upper arm plates, rounded, sharp.

Dimensions.—Specimen exhibiting dorsal surface: Diameter of disk 13 millimeters; arms at least 25 millimeters
long and probably several times this amount; width near disk 2 millimeters, upper arm plates 0.7 to 0.8 millimeter
long. :

Specimen exhibiting ventral surface: Diameter of disk 6.5 millimeters; arm at least 20 millimeters long and
probably at least twice this length judging by taper.

Notes.—The two specimens upon which this species is founded are beautifully preserved molds, the larger one,
which is taken as the type, showing the dorsal surface, the smaller one the ventral. As would be expected, the surfaces
of the disks are considerably crushed and distorted, but enough characteristics are visible to admit of the above
specific description. The specimens have been compared with the recent alcoholics in the collection of the United
States National Museum, but no forms agreeing even remotely with the fossils were found. Both A. H. Clarke and
the'writer are of the opinion that the fossils belong to the genus Amphiura, although, as might be expected in
molds, some of the diagnostic characters are lacking. The species is named in honor of the Santa Cruz quadrangle,

near which the types were obtained.

Locality.—Hills immediately southeast of Scott Valley, 6 miles north-northeast of Santa

Cruz, Santa Cruz County, Cal.
Geologie horizon.—Santa Margarita formation, middle or upper Miocene.

Collection.—Stanford University (1078); U.S. National Museum (165431).
Class ECHINOIDEA.

Subclass REGULARIA ENDOBRANCHIATA.
Order CIDAROIDEA.
Family CIDARIDE.

Genus CIDARIS Leske.
CrpaRIs THOUARSII (2) Valenciennes.

Cidaris thouarsii Valenciennes, 1846, Agassiz and Desor, Cat. raisonné des échinodermes, Soc. nat. Ann., vol. 6, p. 326.
Cidaris sp. a Arnold, 1908, U.S. Nat. Mus. Proc., vol. 34, pp. 351, 359.
Cidaris sp. a Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 701.
Description.—This species, which Arnold has referred to under the name of Cidaris sp. a, is
regarded by H. L. Clark as probably C. thouarsii. He says in a letter quoted by Arnold:
The wax cast [Cidaris sp., a] is a spine of a true Cidaris and very much like many spines of some individuals of the

species of Cidaris common on the west coast of Lower California, Mexico, and Central America, C. thouarsii. I do not
think it shows a single feature by which it can be distinguished from thouarsii, it is certainly from the ancestor of that

species. :
Locality.—Santa Cruz quadrangle, Cal.

Geologic horizon.—Monterey shale, middle Miocene.
Collection.—U. S. National Museum.

180 MESOZOIC AND CENOZOIG ECHINODERMATA OF THE UNITED STATES.

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder ARBACINA.

Family ARBACIIDA.

Genus ECHINOCIDARIS Duncan.
Ecurnociparis sp. MeCrady.

Echino-cidaris sp. McCrady, 1855, in Tuomey and Holmes, Pliocene fossils of South Carolina, Pl. II, figs. 5, 5a.
Arbacia sp. Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description.—An illustration of this form “restored from several fragments” is given by
McCrady but no description is furnished. Its generic relations are very questionable because of
doubt as to the accuracy of the drawing.

Locality.—South Carolina.

Geologic horizon.—Miocene (%).

Collection. —Unknown.

Genus CELOPLEURUS Agassiz.

C@LOPLEURUS IMPROCERUS (Conrad).

Plate LX XXIV, figures 4a-c.

Echinus improcerus Conrad, 1843, Acad. Nat. Sci. Philadelphia Proc., vol. 3, p. 310.
Psammechinus improceras Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

Determinative characters.—Test large, circular, depressed, concave below. Ambulacra
narrow, each with two rows of primary tubercles extending from peristome over ambitus about
two-thirds of way from latter to apical system, secondary tubercles above; poriferous zones
narrow, slightly flexuous. Interambulacra wide, the two rows of primary tubercles on upper
surface small. Peristome large, with slight brachial incisions.

Dimensions.—Diameter 35 millimeters; height 15 millimeters.

Description.—This species was first described by Conrad in 1843. No illustration accom-
panies the description, but the species is without doubt the form found by the authors in the
Yorktown formation near the James River and figured and described in this monograph. It
corresponds in all particulars to the incomplete description which Conrad gives to it.

The test is large, circular and depressed. The slope of the upper surface is very low toward
the apex. The lower surface is concave.

The ambulacra are narrow, each bearing two rows of primary tubercles which are much
larger at the ambitus than on the lower or upper surface. They diminish rapidly in size on the
upper surface and about two-thirds of the way to the apical system become secondaries or
diminish altogether. One or more isolated primaries also occur at this point of disappearance
with a secondary between. The poriferous zones are narrow and somewhat sinuous, the pore
pairs uniserial.

The interambulacra are broad with four rows of primary tubercles at the amibitus similar
to those of the ambulacra. They become smaller, reduced in number, and more or less irregularly
crowded together near the peristome. Above the ambitus the rows of primary tubercles are
soon reduced to two which with diminished size continue to the apical system. A large, miliary
median space is found in the upper portion of each interambulacrum.

The apical system is large but much broken in the type specimen. The peristome is large
with small branchial incisions. The periproct is large and elongate.

Localities.—James River, near Smithfield (type); J. T. Williams’s marl pit, Smith Creck,
half a mile below Suffolk, Va. (figured specimen).

Geologic horizon.—Y orktown formation, upper Miocene.

Collection.—U.S. National Museum (166487).

MIOCENE ECHINODERMATA, 181

C@LOPLEURUS SLOANT Clark, n. sp.

Plate LXXXIV, figures 5a-b.

Determinative characters.—Test moderate size, circular, elevated. Ambulacra narrow,
each with two rows of primary tubercles which rapidly diminish in size above the ambitus.
Interambulacra with median space on upper surface without tubercles. Apical system prom-
inent. Peristome small. Periproct large, subpentagonal.

Dimensions.—Diameter 27 millimeters; height 15 millimeters.

Description.—This species has a test of medium size, circular in ambital outline and much
elevated. The apex is high and the upper surface slopes regularly and rapidly from the ambitus
to it. The lower surface is concave.

The ambulacra are narrow, the poriferous zones being nearly straight and flush. Each am-
bulacrum has two rows of primary tubercles imperforate and noncrenulate, which are very much
larger at the ambitus than above or below. These tubercles are very rapidly reduced in size
on the upper surface and entirely disappear or are replaced by small secondaries as the apical
system is approached.

The interambulacra have similar tubercles to those of the ambulacra, the two outer rows
only on each area continuing to the apical system.

The apical:system is simple and distinct. The peristome is small and the periproct large
and of subpentagonal outline.

Related forms.—C. sloani is quite distinct from C. improcerus, the only other Miocene species
known at the present time. It is much higher and has a quite different distribution of the
primary tubercles.

Locality.—Basticks Landing, Great Peedee River, S. C.

Geologic horizon.—Miocene.

Collection.—U. S. National Museum (166488).

Suborder ECHININA.
Family TRIPLECHINID®.
Genus PSAMMECHINUS Agassiz.
PSAMMECHINUS PHILANTHROPUS (Conrad).
Plate LX XXIV, figures 6a-c.
Echinus philanthropus Conrad, 1843, Acad. Nat. Sci. Philadelphia Proc., vol. 1, p. 310.
Echinus rufjint Forbes, 1845, Geol. Soc. London Quart. Jour., vol. 1, p. 426, figs. a-d.
Echinus rufini Forbes, 1845, Geol. Soc. London Proc., vol. 4, p. 560, text figs.
Echinus philanthropus Conrad, 1846, Am. Jour. Sci., 2d ser., vol. 1, No. 2, p. 220.
Psammechinus ruffint Desor, 1858, Synopsis échinides fossiles, p. 121.
Echinus rufini Emmons, 1858, Agriculture eastern counties: North Carolina Geol. Survey, pp. 306, 307, figs. 239a-d.
Psammechinus philanthropus Meek, 1864, Check list, Miocene, p. 2.
Psammechinus rufini Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 75.

Determinative characters.—Test small, subhemispherical, tumid at the ambitus, somewhat
depressed above, nearly flat below. Ambulacra with two main rows of primary tubercles extend-
ing from peristome to apical system, with a thick median row a portion of distance, poriferous
zones narrow; pore pairs in triplets in oblique rows. Interambulacra with four regular and two
median somewhat irregular rows of subequal primary tubercles at ambitus, the latter reduced
toward peristome and apical system. Peristome rather wide, branchial incisions distinct.

Description.—This species which was described by Conrad m 1843 from material secured
near Smithfield, Va., was described by Forbes two years later as EL. rufini. The test is small
and subhemispherical, with a nearly circular ambital outline. It is tumid at the ambitus, some-
what depressed above and nearly flat below, with a slight depression near the peristomial margin.

The ambulacra are rather narrow, the median portion of each area being covered with two
main rows of primary tubercles, imperforate and noncrenulate, which extend from the peristome

182 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

to the apical system. A third row lies between the other two, and in the larger forms there are
additional tubercles that are best developed near the ambitus and do not reach either peristome
or apical system. The poriferous zones are narrow, and the pore pairs are found in triplets
arranged obliquely.

The interambulacra are covered with tubercles similar to the ambulacra. Six or more rows
of primary tubercles occur, four being very regular and two reaching all the way from the peri-
stome to the anal system. The remaining two rows and in some cases additional rows or extra
subequal tubercles are chiefly developed at the ambitus. The entire surface of both inter-
ambulacra and ambulacra are thickly studded with so many tubercles of about the same size as
to give it a very uniform appearance.

The apical system is small. The peristome is rather wide with moderately distinct branchial
incisions.

Localities—James River and York River (type and figured specimen), Va.

Geologic horizon.—Yorktown formation, upper Miocene.

i UAE tg an Hopkins University (T 1001); Academy of Natural Sciences of Phila-
elphia.
PsaMMECHINUS ExoLETUS McCrady.

Psammechinus exoletus McCrady, 1857, in Tuomey and Holmes, Pliocene fossils of South Carolina, p. 4, Pl. IT, fig. 6.
Psammechinus exoletus Meek, 1864, Check list, Miocene, p. 2. f
Psammechinus exoletus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description.—The fragment briefly described and figured by McCrady is the only material
so far as known that has been found representing this species. The description and figure are
insufficient to separate with certainty this form from other species.

Locality.—Goose Creek, S.C. (Smith.)

Geologic horizon.—Duplin marl, upper Miocene.

Collection —Unknown.

Subclass IRREGULARIA.

Order GNATHOSTOMATA.
Suborder CLYPEASTRINA.
Family FIBULARIID®.
Genus SISMONDIA Desor.

Sismonp1A (?) aRNoLpI Twitchell, n. sp.
Plate LXXXYV, figures la-b.

Astrodapsis sp. indet. Arnold, 1909, U.S. Geol. Survey Bull. 396, p. 30, Pl. XXVIII, fig. 5, 5a.
Astrodapsis sp. indet. Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Description and determinative characters. —This little echinoid, one of the smallest occurring
in the Tertiary deposits of the Pacific coast, was first figured but not described by Ralph Arnold,
of the U. S. Geological Survey, in whose honor the species is named. The test is very small,
being less than half an inch in diameter. In marginal outline it is suboval, with a slight tend-
ency toward the subpentagonal, the anterior end being slightly angulated, the posterior broader
and rounded. The whole form is much depressed, slightly convex above, slightly concave below;
margin of moderate thickness. Apex central. The ambulacral petals are long, reaching the
margin; poriferous zones narrow, diverging in straight lines from apex to margin; pores of both
rows round. The whole test is covered with small but rather conspicuous tubercles. The apical
system is central, with a conspicuous tumid madreporite. The other details could not be made
out on the specimen. The peristome is relatively large, central, subcircular to subpentagonal.
The ambulacral grooves appear as rather well defined, simple, straight lines for a short distance
out from the peristome, beyond which they become obscure. The periproct is very small, circu-
lar, inframarginal, almost marginal.

Dimensions—Length 10.5 millimeters; width 9.5 millimeters.

MIOCENE ECHINODERMATA. 183

Related forms.—S. arnoldi resembles Sismondia (%) coalingaensis and Scutella (%) merriami,
but differs from both in having petals extending to the margin, with straight, diverging porifer-
ous zones.

Locality—Four miles southeast of northwest end of Kettleman Hills, Coalinga district,
California.

Geologic horizon.—Etchegoin formation, upper Miocene and lower Pliocene (?%).

Collection. —U. S. National Museum (165538).

StsMonpDIA(?) COALINGAENSIS Twitchell, n. sp.
Plate LXXXYV, figures 2a-c.

Description and determinative characters.—The test of this species is very small, rarely ex-
ceeding one-half inch inlength. In marginal outline it is suboval to subovate, broader posteri-
orly than anteriorly. The whole form much depressed, slightly tumid centrally; margin rather
thin. Apex subcentral or slightly excentric posteriorly. Lower surface concave.

The ambulacral petals are subelliptical in outline, extending a little more than halfway to
the margin; the posterior pair shorter than the anterior pair; pores round, pairs of pores con-
jugated. The whole test is covered with small but conspicuous tubercles, scattered irregularly.

The apical system is subcentral or slightly excentric posteriorly, coincident with the apex.
The details could not be made out on the specimen studied.

The peristome and ambulacral grooves could not be made out. The periproct is small,
inframarginal, almost marginal.

Dimensions—Length 12 miilimeters; width 10 millimeters; height-2 millimeters.

Related forms.—S. coalingaensis resembles Sismondia (+) arnoldi and Scutella (?) merriami.
From the former it differs in having shorter, subelliptical petals and from the latter in lacking
the tumid petals and in having a more longitudinally oval marginal outline.

Locality—Jacalitos Creek, half a mile east of Kreyenhagen’s, Coalinga district, California.

Geologic horizon.—Etchegoin formation, upper Miocene and lower Pliocene (*).

Collection —U. 8S. National Museum (165717).

Family SCUTELLID®.

Genus SCUTELLA Lamarck.

ScuTELLA ANDERSONI Twitchell, n. sp.
Plate LXXXYV, figures 3a-d.
Scutella sp. A., F. M. Anderson 1905, California Acad. Sci. Proc., 3d ser., Geology, vol. 2, No. 2, p. 193, Pl. XIII, fig. 8.

Determinative characters —Test small; suboval to broadly subovate, broadest posteriorly;
margin thin, more so posteriorly than anteriorly, with rather pronounced notches opposite the
posterior petals; the whole form greatly depressed, the upper surface ridged along the longitu-
dinal median line, sloping rather steeply away from the ridge to the side edges; apex excentric
anteriorly; under surface slightly concave longitudinally. Apical system decidedly excentric
anteriorly, about coincident with the apex. Posterior ambulacral petals slightly longer than the
anterior paired petals which are slightly longer than the odd petal. Peristome excentric anteri-
orly. Periproct very small, supramarginal.

Dimensions.—Length 25 millimeters; width 25 millimeters; height 5 millimeters.

Description —This interesting species was briefly described and figured in 1905 by F. M.
Anderson but was not given a specific name. It is here named in honor of Mr. Anderson. The
test is small, ranging from less than a half to slightly more than an inch in diameter. In mar-
ginal outline it is suboval to broadly subovate; broadest posteriorly, usually about as long as
wide. The margin is thin, more so posteriorly than anteriorly, with rather pronounced notches
opposite the posterior petals and sometimes with faintly defined notches opposite the anterior
paired petals. The whole form is greatly depressed; the upper surface having a more or less
well defined ridge extending along the longitudinal median line and involving the odd petal,

184 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

the inner ends of the other petals, and the inner portion of the posterior interambulacrum; from
the median ridge the surface slopes at first steeply then gradually away to the side edges. The
under surface is slightly concave longitudimally. The apex is excentric anteriorly, at the highest
point of the median ridge.

The ambulacral areas are rather narrow; the dorsal portions petaloid. The petals are
moderate in size, subelliptical, extending more than halfway to the margin, open at the ends, the
odd petal more widely open than the others. The poriferous zones are relatively wide, though
slightly less so than the interporiferous areas; pores oval, pairs of pores conjugated.

The interambulacral areas are rather broad with the exception of the odd posterior area,
which is narrow. The surface of the test is covered with small uniform tubercles.

The apical system is decidedly excentric anteriorly, about coincident with the apex. There
is a large, subcircular madreporite, four large genital pores, of which the anterior pair are some-
what nearer together than the posterior pair, and five small radial plates each perforated by a
minute pore.

The peristome is excentric anteriorly. The character of the ambulacral furrows can not
be made out on the specimens studied.

The periproct is very small, circular and supramarginal, almost marginal.

Related forms.—S. andersoni is readily distinguished from all other American scutellas
by its longitudinally ridged upper surface, its longitudinally concave lower surface, and its
pronounced marginal notches opposite the posterior paired petals.

Localities.—West of Coalinga (Anderson), and Devils Den district, Kern County (figured
specimen), Cal.

Geologic horizon.—Tejon formation, upper Eocene; 2 Waganes sandstone, lower Miocene.

Collections. —U. 8. National Museum (165719) ; Chileans Academy of Shines,

SCUTELLA FAIRBANKsI Pack.
Plate LXXXYV, figures 4-6.
2Scutella gabbi Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 168, Pl. XXII, figs. 5, 5a.
Scutella fairbankst (Merriam, MS.) Arnold, 1907, U.S. Nat. Mus. Proc., vol. 32, p. 542, Pl. XLII, fig. 3, Pl. XLII, fig,
3. No description.
Scutella fairbankst Eldridge and Arnold, 1907, U. S. Geol. Survey Bull. 309, pp. 13, 17, 230, 232, PI. XXIX, fig. 3

Pl. XXX, fig. 3. No description.

Scuteila fairbanksi Pack, 1909, Univ. California Dept. Geology Bull., vol. 5, No. 18, pp. 276-277, PI. XXIII, fig. 1.
?Scutella merriami Arnold, 1909, U. S. Geol. Survey Bull. 396, Pl. VI, fig. 4. Figure only.

2Scutella merriamt Arnold and R. Anderson, 1910, U. S. Geol. Survey Bull. 398, Pl. XXVIII, fig. 4. Figure only.
Echinarachnius fairbanksi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Determinative characters.—Test medium in size; subcircular, transversely oval or broadly
subovate, slightly broader than long; margin markedly thin and faintly undulating, submarginal
area wide; the whole form greatly depressed, the upper surface rising gradually sind very gently
from the margin to the low central’or subcentral apex; under surface flat or nearly so. Apical
system central or slightly excentric anteriorly and about coincident with the apex. Ambula-
cral petals relatively short, subequal in size, subsymmetrical as a group; the odd petal differing
from the rest in having its inner row of pores diverging gradually to the end, which is wide open,
much more so than in the other petals. Peristome central or subcentral; main ambulacral
furrows deep and probably simple and straight for most of the distance to the margin, then
branching. Periproct very small, supramarginal.

Dimensions.—Specimen A (type): Length 53 millimeters; width 49 millimeters (Pack).
Specimen B: Length 33 millimeters; width 36 millimeters.

Description.—This new Californian Scutella has a test which is of medium size, ranging
from about 1 to 24 inches in diameter. In marginal outline it is somewhat variable, being
sometimes subcircular, sometimes transversely oval, sometimes broadly subovate. The margin
is markedly thin and faintly undulating, submarginal area wide. The whole form is greatly
depressed; the upper surface rising gradually and very gently from the margin to the low, central
or subcentral apex. The under surface is flat or nearly so.

MIOCENE ECHINODERMATA. 185

The ambulacral areas are rather wide at the margin, where they equal or exceed the inter-
ambulacral areas, widening rapidly from the ends of the lateral and posterior petals, less rapidly
from the odd petal; dorsal portions petaloid. The petals are relatively short, almost symmetrical
as a group, almost equal in size, extending from one-half to almost two-thirds the way to the
margin, all but the odd petal subelliptical in outline, tending to close at the ends; the odd petal
noticeably differs from the rest in form, having its inner rows of pores diverging gradually to the
end, which is wide open, much more so than that of the other petals. The poriferous zones are
relatively wide; pores oval; pairs of pores conjugated; interporiferous areas of the anterior
paired and posterior petals rather narrow, not much wider than the poriferous zones, that of the
odd petal considerably wider, especially at the outer end of the petal. Several pairs of pores, in
strongly diverging rows, extend beyond the ends of the petals.

The interambulacral areas are all rather narrow between the petals, broad from about oppo-
site the ends of the petals to the margin. The surface of the test is covered with small uniform
tubercles, which are somewhat larger on the under surface, especially near the peristome.

The apical system is central or slightly excentric anteriorly and about coincident with the
apex. The details are obscure on the specimens, but there are four large genital pores of which
the two anterior are nearer together than the posterior pair.

The peristome is central, or subcentral, shghtly depressed; ambulacral furrows, according to
Pack, are “deep and traceable to the margin,” where they ‘‘show aslight tendency to branch.”
On the specimens studied they are not well shown.

The periproct is very small, supramarginal; sometimes located at a distance from the edge
equal to its own diameter.

Related forms.—S. fairbanksi 1s most closely related to S. gabbi (Rémond) Merriam, but dif-
fers from it, according to Pack, in ‘attaining a greater size, in haying a slightly undulating mar-
ginal outline, in having deeper and better marked furrows on the actinal surface, and in having
the anal pore entirely upon the upper surface.” S. fairbanksi is also allied to Dendraster
interlineatus and D. oregonensis, but may be easily separated from both by its more central
apical system, shorter and more equal petals, and wider marginal area. It also differs from
D. oregonensis in haying the posterior poriferous zones of its paired petals curving.

The specimen figured by Arnold as Scutella merriami was probably a young specimen of
S. fairbanksi.

Localities —Near Torrey Canyon wells, southwest of Piru, Ventura County, Cal. (Arnold);
Sespe Canyon, Ventura County, Cal. (Pack, Arnold).

Geologic horizon—V aqueros formation, lower Miocene.

Collections —U.8. National Museum (164963, B, C); University of California (A).

ScuTeLtLta (?) MERRIAME (Anderson).
Plate LXXXY, figures 7a-c, Sa—b.
Astrodapsis merriami F. M. Anderson, 1905, California Acad. Sci. Proc., 3d ser. Geology, vol. 2, No. 2, pp. 193-194, Pl.
XIV, figs. 33, 34.

Scutella merriami Arnold, 1909, U. S. Geol. Survey Bull. 396, p. 18.
2Scutella merriami Arnold, 1909, figure, U. S. Geol. Survey Bull. 396, Pl. VI, fig. 4.
Scutella merriami Arnold and R. Anderson, 1910, U. S. Geol. Survey Bull. 398, pp. 85, 86, 87.
?Scutella merriami Arnold and R. Anderson, 1910, figure, U. S. Geol. Survey Bull. 398, Pl. XXVIII, fig. 4.
Sismondia merriami Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 702.

Description.—This little echinoid was first described and figured by F. M. Anderson in 1905.
Its button-like appearance and its abundance in certain deposits in the Coalinga district of Cali-
fornia have led to these deposits being designated Button beds. The writer has had about 20
specimens from the Button beds available for study, most of which probably belong to this
species; but most of them were in poor condition and as the type could not be secured for com-
parisons the description of F. M. Anderson is here given verbatim:

Disk small, circular, depressed; margin only slightly notched at the ambulacral extremities; apex central, only
slightly elevated, star symmetrical, petals equal but not reaching the margin of the disk, and slightly elevated; anal

186 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

pore marginal; ambulacral furrows of inferior surface straight and simple. The largest specimens have a diameter of 14
inches, though the usual size is three-fourths of an inch. The disk is thinand flattened but shows a decided tendency
to form elevated stars on the upper surface.

The writer’s study of the specimens from the Button beds already referred to suggests a few
comments in connection with this description. The size of the specimens studied ranged from 8
to 15 millimeters in diameter. The marginal outline was usually circular, but sometimes longi-
tudinally oval. The marginal notches are often hardly discernible. The petals extend from
half to two-thirds the way to the margin. In some specimens the petals were practically flush
with the surface and in some were slightly tumid. In some the poriferous zones of all the petals
diverge continuously and are wide open at the ends, though the odd petal is somewhat more
widely open than the rest; in others those of all but the odd petal are partly closed, as m the
form figured by Anderson. In the form figured by Arnold (which has been examined by the
writer) the poriferous zones of all but the odd petal diverge for about half their length, then con-
verge to a less degree so that at their ends they are only slightly nearer together than
midway, those of the odd petal diverging continuously to their ends, where they are far apart,
the inner lines of pores forming a well-defined V. In view of the variations indicated it
seems probable that among the small echinoids of the Button beds there are several forms,
possibly distinct species, which closely resemble each other in general appearance, while differing
in details. The lines between these forms can only be drawn by one who has access to the type
and to an extensive series of good specimens. However, the writer is of the opinion that, in view
of Anderson’s significant remark that the test ‘‘shows a decided tendency to form elevated stars
on the upper surface,”’ the small buttonlike forms with slightly tumid petals are most typical of
the species S. merriami. Some of the larger specimens assigned to S. merriami—such as the one
figured by Arnold—strongly resemble Scutella fairbanksi and, with further collecting and com-
parative study with the types of the forms involved in hand, may prove to be young specimens
of that species. Aside from its smaller size, the only important apparent difference between
Arnold’s figured form and S. fairbanksi is that the periproct is exactly marginal, visible from
above and below; butit may be found that S. fairbanksi, which is somewhat variable in regard to
this feature, may vary enough to include forms with a marginal periproct.

There is some doubt in regard to the generic position of the present species. There seems to
be no good ground for placing it in the genus Astrodapsis, as it lacks the depressed apical system
and deeply impressed interambulacral areas characteristic of that genus. Anderson says that
the ambulacral furrows are straight and simple, which, if true, would suggest placing it in the
genus Sismondia, but on the other hand in the figure of the under surface given by Anderson the
furrows appear to be simple and straight for about two-thirds of the way to the margin and then
bifurcate symmetrically, which fact points toward the genus Scutella. It isnot improbable that
both genera may be represented. The ambulacral furrows are not discernible upon the speci-
mens studied by the writer, and the form is therefore, for the present, placed doubtfully in the
genus Scutella.

Localities —Tar Springs, Kreyenhagen’s and Temblor, Mount Diablo Range, California
(F. W. Anderson); Garza Creek gorge in Reef Ridge, Canoas Canyon, near Hugo Kreyenhagen’s
place, and 84 miles north of Coalinga, all in the Coalinga district, California (Arnold); Wagon-
wheel Mountain, Devils Den district, Kern County, Cal. (Arnold).

Geologic horizon.—V aqueros formation, lower Miocene. Occurs in the Button beds, which
are near the middle of the formation.

Collections —U. S. National Museum (165584, B; 165716, A); California Academy of
Sciences; F. M. Anderson.

ScUTELLA NoRRISI Pack.

; Plate LXXXYV, figure 9.
Scutella (2) norrisi Pack, 1909, Univ. California Dept. Geology Bull., vol. 5, No. 18, pp. 277-278, Pl. XXIII, fig. 3.
Echinarachnius norrisi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.
Description.—Since no opportunity has been had of studying any specimen of this species
the description of Pack is given verbatim:

MIOCENE ECHINODERMATA. 187

Test subcircular in general outline, with deep, broad, marginal notches in the edges of the ambulacral areas. The
two posterior notches are much deeper than are the anterior ones, and truncate the posterior interambulacral space on
either side of the median line, shaping the posterior end of the test into a prominent process. The test when viewed
from above has a leaf-like appearance. Test much depressed, edges markedly thin, abactinal surface very slightly
arched, apex central; actinal surface flat or gently concave. Mouth central, slightly sunken; ambulacral furrows
poorly shown in the specimens examined, but evidently branch but little, ifatall. Main ambulacral grooves continue
from the mouth to the margin, entering the marginal notches. Anal pore small, inframarginal. Ambulacral star cen-
tral. Petals extend about three-fourths the distance to the margin and not entirely closed at the ends.

Dimensions.—Longitudinal diameter, 55 millimeters.

As only a single figure of this form is given by Pack,! and as that too is one of the under sur-
face of a weathered specimen, it is hardly possible to discuss the form intelligently. However,
it may be said that the marginal outline, with its five large ambulacral notches alternating with
broad, blunt, rounded projections differentiates the form from all other known Californian echi-
noids. From the description and figure the form appears to be a Scutella. The resemblance of
the present species to Astrodapsis whitneyi which Pack remarks upon in connection with his
description of A. antiselli is but a slight one, as the notches of A. whitney? are not nearly as large.

Localitues—Five miles northwest of the Stone Canyon coal mine, Monterey County, and at
San Juan River near La Panza, San Luis Obispo County, Cal.

Geologic horizon.—V aqueros formation, lower Miocene.

Collection —University of California.

ScUTELLA ABERTI Conrad.

Plate LXX XVI, figures la-b; Plate LX X XVII, figures la-d.

Scutella aberti Conrad, 1842, Nat. Inst. Promotion Sci. Proc., 2d Bull., p. 194, no figure.

Scutella alberti Bronn, 1848, Index palzontologicus, vol. 1, p. 1125, vol. 2, p. 196.

Scutella alberti Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Scutella alberti Dall, 1892, U. S. Geol. Survey Bull. 84, p. 52.

Scutella aberti Clark, 1904, Maryland Geol. Survey, Miocene, p. 432, Pl. CXXIX, figs. 2, 2a, and Pl. CXX, figs. la,
Tb, 2a, 2b.

Scutella aberti Clark, 1906, Maryland Geol. Survey Rept., vol. 6, p. 258, Pl. XXII, fig. 17.

Scutella aberti Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

Determinative characters —Test large to very large, subcircular to subquadrate in marginal
outline, the whole form much depressed, less so within the large petaloidal area where it rises in
the form of a low, broad mound whose flattened summit is excentric anteriorly, margin relatively
thin, with three large, broad notches in the posterior border, between which the test extends in
the form of two large, broad, blunt projections; under surface flat. Ambulacral petals very
large, subspatulate, extending more than two-thirds the way to the margin. Apical system
slightly excentric anteriorly but less so than the apex. Peristome small, subpentagonal, ambu-
lacral furrows simple and straight for a short distance from the peristome, then forking, the
branches proceeding somewhat sinuously and divergingly to the margin. Periproct very small,
subcircular, inframarginal, near the head of the pointed central notch in the posterior border,

Dimensions—Length 120 millimeters; width 121.5 millimeters; height 14 millimeters.
The largest specimen examined was 178 millimeters in diameter.

Description.—This species, the largest of American Scutellas, was first reported in 1842 by
Conrad, who described but did not figure it, and who named it after Col. J. J. Abert, of Washing-
ton, D.C. It was first figured by Clark in 1904. The form has been but little known owing to
its limited distribution and to the obscure and out of the way character of the publication in
which Conrad’s description was published. Perfect specimens are rare; imperfect ones and
fragments are very abundant in the thin bed in which it occurs and to which it appears to be
restricted. It is not known positively to occur outside of Maryland. Several authors have

1 Since the above description was written Pack has published additional details regarding S. norrisi, based on recently discovered material
(Univ. California Dept. Geology Bull., vol. 7, No. 13, pp. 299-300, Pl. XV, fig. 1). The new material establishes on firm foundation this new
Species, which is unlike all other California scutellid forms.

188 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

given the name of the form as S. alberti instead of S. aberti, as it should be. The test is large to
very large in size, ranging from 90 millimeters to about 180 millimeters in diameter. In mar-
ginal galling it is suiboinenlen to subquadrate, broader posteriorly than anteriorly, sometimes
very noticeably so. The whole form is much depressed although more so around the margin,
within the large area covered by the ambulacral petals it rises in Abe form of a low broad eit
rounded mound which varies in height from about 4 to about ? inch, and the summit of which is
flattened and excentric anteriorly. The margin of the test is relatively thin and undulating;
with a faint, broad, shallow curved notch opposite each of the three anterior petals, two large,
broad, deep, curved notches opposite the posterior pair of petals and one large, broad, deep,
pointed notch in the middle of the posterior edge. Between the large central notch and each
of the large curved notches the test extends in the form of a large, broad, blunt projection; the
two projections and three large notches together forming the whole posterior border of the test.
The under surface is flat. The apex is decidedly excentric anteriorly, at the summit of the
tumid central area.

The ambulacral areas are narrow in the petaloid region, but very broad in the margina
region, where they are considerably wider than the interambulacral areas. The dorsal portions
of the ambulacra are petaloid. The petals are very large, subequal in length, the posterior pair
being somewhat longer than the others; subspatulate to Indian-club shape in form; nearly
lowed at the ends; exteniine more hava two-thirds the way from the center to the margin.
The poriferous zones are wide, wider than the interporiferous areas; the inner row of pores eal.
outer row slitlike, pairs of pores conjugated, the groove lines continuing beyond the inner row :
pores to the center of the sariauponiereme areas, and the spaces between “dhe grooves very narrow.

The interambulacral areas are broad near the ends of the petals, but ‘baganne narrower toward
both center and margin. The plates are polygonal and are very large, especially those on the
under surface. Single plates are often found in a more or less weathered condition showing on
both their upper and under surfaces numerous grooves and ridges. The whole surface of the test
is covered with small uniform tubercles which are slightly larger on the under surface.

The apical system is relatively large, slightly excentric snoconly on the flattened surface
posterior to the apex of the test. The fadineparite | is relatively large, subpentagonal, occupying
the larger part of the area covered by the system and flush an the surface. There are five
small genital pores near the points of the madreporic pentagon and five small triangular radial
plates each perforated by a very small elliptical pore. —

The peristome is relatively small, subcircular to subpentagonal, subcentral; the ambulacral
furrows simple and straight for a show’ distance from the peristome, then for king and diverging
nearly symmetrically, each pair of branches proceeding 1 in a more or less sinuous course and with-
out branching for over half the way to the margin, then branching considerably, the branches
being given off on the inside of the more important fucnom, which continues to diverge more and
more as the margin is approached.

The periproct is both relatively and actually very small, subcircular, inframarginal, a short
distance in from the point of the large, central notch in the posterior border.

Related forms—This species is not closely allied to any other American form. It bears a
superficial resemblance to Periarchus lyelli and P. altus but is readily separated from each of
them by the character of its ambulacral furrows, its inframarginal periproct, and the large
projections and notches in its posterior margin. It ij is similar in general features to two Romaien
forms—S. subrotunda Lamarck,' from the lowe: Miocene of Bordeaux, France, and S. tarra-
conensis Lambert, from the Burdigalien Miocene of Barcelona, Spain. From each, however, it
can be easily distinguished by its much more pronounced posterior notches and projections and
by its less conta apes

Lo arf, St. Marys County, (figured specimen), Governor Run, Calvert
County, an ain Bales Dorchester County, Md.

1 Agassiz’s monograph Des scutelles, pp. 76-78, Pl. XVII, figs. 1-9. Desor, in Synopsis des échinides, p. 232, says that S. subrotunda Lamarck
is from the lower Miocene.

MIOCENE ECHINODERMATA, 189

Geologic horizon—Choptank formation, middle Miocene.
Collections —Maryland Geological Survey; Johns Hopkins University; U. S. National
Museum; Academy of Natural Sciences of Philadelphia.

ScureLLa GABBI (Rémond) Merriam.

Plate LXX XVIII, figure la-b.

?Clypeaster gabbi Rémond, 1863, California Acad. Sci. Proc., vol. 3, pp. 53, 54, no figure. See description on page 211
of the present work.

?Clypeaster gabbi Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.
?Clypeaster gabbi Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, pp. 36, 109, Pl. XII, figs. 64, 64a.
?Clypeaster gabbi Cooper, 1888, Cat. California fossils: State Mineralogist Seventh Rept., p. 271.
Scutella gabbi Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 168, Pl. XXII, figs. 5, da.
Echinarachnius gabbi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Description.—The writer has been unable to obtain any specimens! of this form. The
description of Merriam will therefore be repeated verbatim:

Test circular, much depressed, margin thin. Average specimens 25 to 30 mm. in diameter, largest specimens
ranging up to 40 and 45 mm. in diameter. ;

Petals short, not extending more than two-thirds of the distance to the margin; excepting the anterior one, they are
nearly closed at the ends. Anterior petal wide open. Except in the anterior area the ambulacral plates suddenly
enlarge and the area rapidly widens beyond the ends of the petals. In these areas, pairs of small, round pores, diverging
strongly from the ends of the petals, may be present almost to the margins. In the anterior petal the plates do not
enlarge as noticeably toward the margin as in the others. neither do the more persistent pore pairs diverge as much.

Apical shield with four genital pores, there being none at the end of the posterior interambulacral area. Anus
marginal to supramarginal; in quite a number of specimens it is found to be entirely on the upper surface. No marked
difference is noticeable between the tubercles of the upper and lower suriaces.

The ambulacral furrows of the actinal surface are not usually well preserved and have been clearly seen on only a
few specimens; they divide dichotomously a little less than half way to the margin.

Related forms.—The form described and figured by Merriam differs in several respects from
that originally described by Rémond. Rémond’s was subelevated, comparatively thick and
with margin rounded. Merriam’s is much depressed, and with margin thin. The petals of
Rémond’s form were elongated and open at their extremities—those of Merriam are short and,
excepting the anterior one, are nearly closed at the ends. In Rémond’s form the ambulacral
furrows are straight, which led to his placing the form im the genus Clypeaster; in Merriam’s
the furrows divide dichotomously a little less than half way to the margin, which indicates a
Scutella. These differences are too important to be ignored and raise the question whether
Merriam has described and figured identically the same form as Rémond. The location of
Rémond’s type is unknown and he failed to give any figures; but his other work is of too high an
order to justify any radical departure from his description, and his form is therefore placed in the
synonomy of the present species with an interrogation mark as indicative of the doubt that
exists inregard tothe matter. It is not at all improbable that the investigator who obtains con-
siderable material from Rémond’s locality, San Pablo Bay, south of Mare Island, Cal., may dis-
cover a form more nearly corresponding to Rémond’s description than the one here described.

Merriam’s Scutella gabbi is most closely related to S. fairbanksi, which, however, differs,
according to Pack, in ‘‘attaining a greater size, in having a slightly undulating marginal outline,
in having deeper and better marked furrows on the actinal surface, and in having the anal pore
entirely upon the upper surface.”

Localities —San Pablo Bay (Rémond, Gabb, Merriam, Weaver); Walnut Creek (Gabb,
Weaver) ; and Martinez (Gabb), Cal.

Geologic horizon.—San Pablo formation, upper Miocene. Merriam states that it occurs in
the lowest beds of the San Pablo formation.

Collection.—University of California (19425).

1 Since this description was written the specimen figured was lent to the writer by Merriam. A study of this specimen strengthens the writer’s
doubt as to its being the same form as that described by Rémond. It has also made him inclined to regard Merriam’s S. gabbi as very probably
the same as S. fairbanksi Pack.

39800°—15,

13

190 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Genus DENDRASTER Agassiz emend.

Dendraster L. Agassiz, 1847, Cat. raisonné échinodermes; Soc. Nat. Ann., vol. 7, p. 135.

Echinarachnius A. Agassiz, 1872 (subgenus) pars, Revision of the Echini, Mus. Comp. Zoology Tus. Cat. 7, pp. 107, 524,
Echinarachnius Duncan, 1891 (subgenus) pars, Revision genera and great groups Echinoidea, p. 158.

Echinarachnius Grabau and Shimer, 1910, North American index fossils,.p. 592.

The genus Dendraster as used here is that of Agassiz with a slight amendment enlarging it.
It is here regarded as including the Scutella-like forms having a decidedly posteriorly excentric
apical system, very unequal petals, ambulacral furrows bifurcating near the peristome, and the
periproct inframarginal, marginal, or supramarginal. The species D. excentricus is the type of
the genus.

Some confusion exists in regard to the forms included im the present genus by reason of the
use of the generic term Echinarachnius by some authors as a subgenus of Scutella for the forms
having an excentric apical system. Duncan is partly responsible for this, having proposed it
in his revision of the Echinoidea. In Eastman’s translation of Zittel’s Paleontology the sug-
gestion of Duncan was carried out, and in Grabau and Shimer’s ‘Index fossils of North
America”’ more positive action was salkern by divorcing Echinarachnius from Scutella eine still
ascribing it, and basing it essentially upon, the excentric apical system.

The. genus Bena achnius was established by Leske in 1778, what is evidently his type
species being Echinus placenta Linné. Neither this species nor any of the allied forms he
incidentally mentioned had an excentric apical system. The species placenta is now recognized
(though with doubtful propriety) as the type of the genus Arachnoides Klein. (See p. 124.)
Gray, in 1825, redrew and enlarged Echinarachnius Leske, retaining placenta as the type species
and adding Scutella parma Lamarck and Scutella lenticularis Lamarck, neither of which has an
excentric apical system. A. Agassiz, in 1872, reduced Echinarachnius to the rank of a sub-
genus under Scutella; distinguishing it chiefly by having “‘interior pillars more or less concentric
with the edge,” and including both forms with central apical system, H. parma, and excentric
apical system, Hf. excentricus. In view of these facts it is difficult to see any grounds for the
use of the name Echinarachnius for forms with an excentric apical system.

As a result of the discovery in California deposits of many specimens, including several
new species, having an excentric apical system, the writer has been led to differ with A. Agassiz
and regards the excentricity of the apical system as a fundamental and satisfactory basis of
separation and therefore regards the genus Dendraster L. Agassiz as well founded. Stefanani+
appears to have come to the same conclusion.

DENDRASTER PERRINI (Weaver).

Plate LX XXVIII, figures 2, 3a-c.

Scutella perrint Weaver, 1908, California Univ. Dept. Geology Bull., vol. 5, No. 17, p. 273, Pl.-XII, fig. 2

Astrodapsis perrint Rathbun, 1908, U. 8. Nat. Mus. Proc., vol. 35, p. 342. Listed on authority of R. Arnold and
erroneously ascribed to Merriam.

Scutella perrint Arnold, 1909, U. 8. Geol. Survey Geol. Atlas, Santa Cruz folio (No. 163), p. 6.

Scutella perrint Arnold, 1909, U. S. Geol. Survey Bull. 396, pp. 30, 34, 38, 162, Pl. XXVIII, figs. 1, 2

Echinodiscus (?) perrini Lambert, 1909, Rey. crit. paléozoologie, vol. 13, p. 122

Scutella perrini Arnold and Anderson, 1910, U. S. Geol. Survey Bull. 398, p. 338, Pl. L, figs. 1, 2.

Merriamaster perrini Lambert, 1911, Rev. crit. paléozoologie, vol. 15, p. 64.

Merriamaster perrint Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 704.

Determinative characters.—Test medium in size; usually circular rarely longitudinally oval
in marginal outline, ‘broadest centrally; upper surface greatly depressed, slightly convex, rising
gradually from the unusually thick margin to the low apex which is slightly excentric anteriorly ;
under surface concave. Tubercles conspicuous, nearly equally so over the whole test; not
close together. Apical system excentric posteriorly, from about one-sixth to about one-fifth
the radius from the center. Ambulacral petals large, wide, broadly subelliptical, all of them
extending nearly to the margin, wide open at the ends; interporiferous areas very wide, some-
times faintly tumid, the posterior paired petals shorter than the others, though less so than in

1Stefanani, G., Soc. geol. italiana Boll., vol. 33, p. 704.

MIOCENE ECHINODERMATA. 191

allied forms and less divergent than the anterior pair. Peristome small, slightly excentric
posteriorly; ambulacral furrows straight and simple for a short distance from the peristome,
then forking, the branches diverging and extending nearly to the margin. Periproct very
small, circular, inframarginal, nearly marginal. y

Dimensions.—Largest specimen studied: Length 58 millimeters; width 58 millimeters:
height 10 millimeters. Specimen A: Length 46 millimeters; width 43 millimeters; height
9 millimeters. Specimen B: Length 45 millimeters ;. width 43 millimeters; height 9 millimeters.

Description.—The test of this recently described Californian species is medium in size,
ranging from about 14 to nearly 24 inches in diameter. In marginal outline it is usually circular,
though sometimes longitudinally oval; broadest opposite the middle. The upper surface is
greatly depressed, slightly convex, rising gradually from the margin to the apex, which is low, and
slightly excentric anteriorly. The margin is unusually thick for a scutellid form and the sub-
marginal area beyond the ends of the petals is very narrow. The under surface is concave; the
concavity gradually increasing from the margin to the peristome, where it is from a fourth to
a third of the height of the test.

The ambulacral areas are wide, widest at the margin where they are wider than the inter-
ambulacral areas; dorsal portions petaloid. The petals are large, the total area covered by
them being greater relatively than in most related forms, wide, and widening rapidly near the
apical system; broadly subelliptical in outline; the anterior pair longer than the posterior pair
though less so than in allied forms, the odd petal slightly longer than the anterior pair, all
of them extending nearly to the margin and wide open at the ends; the posterior pair less
divergent than the anterior pair. The poriferous zones are of moderate width, pores oval;
pairs of pores conjugated. The interporiferous areas are unusually wide, from three to four
times as wide as the poriferous zones and sometimes faintly tumid on unweathered specimens.

The interambulacral areas are rather narrow and nearly equal in width between the petals,
wide at the margin. The whole surface of the test, including the margin and the interporiferous
areas, is covered with perforate tubercles which are relatively larger and more conspicuous than
in most related forms and which project above the edges of the wide scrobicules in which they
are placed. The tubercles are only slightly larger on the under than on the upper surface and
they are not very close together.

The apical system is excentric posteriorly, though less so than in most related forms, being
situated from about one-sixth to about one-fifth the distance from the center to the posterior
margin. There is a large subpentagonal madreporite, four genital pores situated at the points
of the pentagon, the anterior two being nearer together than the posterior two, and five small
radial plates each perforated by a minute pore.

The peristome is small, circular, slightly excentric posteriorly just beneath the apical
system; ambulacral furrows straight and simple for a short distance from the peristome, then
forking, the branches diverging and extending almost to the margin.

The periproct is very small, circular, inframarginal, nearly marginal.

Related forms.—D. perrini is closely related to D. arnoldi, but can be separated from it by
its larger petaloidal area, its wider and less tumid interporiferous areas, its broader and less
gradually widening petals, and its relatively longer posterior petals.

In its circular form and its thick margin D. perrini presents an interesting resemblance to
Mortonella quinquefaria, but is easily separated by its posteriorly excentric apical system, its
relatively larger petalloidal area and narrower submarginal area, and by the inframarginal
position of its periproct.

Lambert’s genus Merriamaster is not recognized, as it is based on the erroneous idea that the
ambulacral furrows are simple as in Laganum.

Locality.— Zapato Creek, one-half mile south of A. Kreyenhagen’s place, Coalinga district,
California.

Geologic horizon.—Etchegoin formation (apparently limited to the upper portion), upper
Miocene and lower Pliocene (?).

Collections.—U. S. National Museum (165560, A, B); University of California.

192 MESOZOIC AND’ CENOZOIC ECHINODERMATA OF THE UNITED STATES.

DENDRASTER ARNOLDI Twitchell, n. sp.

Plate LX XXVIII, figures 4a-d.

Astrodapsis? sp. a Arnold, 1909, U. S. Geol. Survey Bull. 396, p. 162, Pl. XXVIII, figs. 3, 3a.
Astrodapsis? sp. a ‘Arnold, 1910, U. S. Geol. Survey Bull. 398, p. 338, Pl. L, figs. 3, 3a.

Determinative characters.—Test small to medium in size; subcircular to broadly oval in
marginal outline, usually longitudinally elongate, more rarely transversely elongate, broadest
centrally; upper surface greatly depressed, slightly convex, rising gradually from the mod-
erately thick margin to the low, central apex; under surface concave. Tubercles crowded
and conspicuous, notably so within the interporiferous areas and between the ambulacral
furrows. Apical system excentric posteriorly, from about one-fifth to about one-fourth
the radius from the center. Ambulacral petals of medium size, extending from one-half to
two-thirds the way to the margin, wide open at the ends, moderately wide; interporiferous
areas notably tumid; the posterior paired petals decidedly shorter than the rest and relatively
shorter than in closely related forms. Peristome small, central or subcentral; ambulacral
furrows straight and simple for a short distance from the peristome, then forking, the branches
diverging and extending nearly to the margin. Periproct very small, circular, inframarginal,
nearly marginal.

Dimensions.—Type specimen: Length 45 millimeters; width 43 millimeters; height 7
millimeters. Small, transversely elongate specimen: Length 22.5 millimeters; width 24
millimeters; height 5 millimeters.

Description.—This species is found in association with D. perrini and D. coalingaensis
in the Etchegoin formation of California. Itis rather an abundant form. A number of specimens
were collected by Dr. Ralph Arnold, of the United States Geological Survey, and one was
figured by him. The species is therefore named in his honor. The writer found several specimens
among the material studied which showed bifurcating ambulacral furrows, thus proving the form
to be allied to Scutella, instead of belonging to Astrodapsis, the genus to which Arnold doubtfully
referred the form he figured. The test of this species is small to medium in size, ranging from
less than one-half to nearly 2 inches in diameter. In marginal outline it is subcircular to broadly
oval, usually longitudinally elongate more rarely transversely elongate, broadest opposite the
middle or slightly to the rear of the middle. The upper surface is greatly depressed, slightly
convex, rising gradually from the margin to the apex, which is low and central or subcentral.
The margin is of moderate thickness, though somewhat variable, sometimes approaching the
thickness of that of D. perrini. The under surface is concave, the concavity gradually increasing
from the margin to the peristome.

The ambulacral areas are wide, widest at the margin, where they are wider than the inter-
ambulacral areas; dorsal portions petaloid. The petals are of medium size, moderately wide
and tending to widen gradually to near their distal ends, extending from one-half to two-thirds
the way to the margin, the anterior pair decidedly longer than the posterior pair, the odd petal
slightly longer than the anterior pair; more subspatulate than subelliptical in outline; wide open
at the ends. The poriferous zones are wide, pores oval, pairs of pores conjugated. The inter-
poriferous areas are rather wide, usually from two to three times the width of the poriferous
zones, and notably tumid.

The interambulacral areas are rather narrow between the petals, wide at the margin. The
whole surface of the test is covered with tubercles which are crowded and relatively conspicuous,
projecting above the edges of the rather wide scrobicules and being especially conspicuous within
the interporiferous areas and between the ambulacral furrows.

The apical system is excentric posteriorly, situated from about one-fifth to about one-
fourth the distance from the center to the posterior margin. The madreporite is large and there
are four genital pores, the anterior two being nearer together than the posterior two, uum. five
small radial plates each perforated by a minute pore.

The peristome is small, subcircular, central, or subcentral; ambulacral furrows straight and
simple for a short distance from the peristome, then forking, the branches diverging and extend-
ing nearly to the margin.

MIOCENE ECHINODERMATA.,. 193

The periproct is very small, circular, nframarginal, nearly marginal.

Related forms.—D. arnoldi is closely related to D. perrini, but can be separated from it by
its smaller petaloidal area and broader submarginal area, its relatively shorter posterior petals,
its narrower interporiferous areas, and its narrower and less rapidly widening petals. D. arnoldi
is liable to be confused with D. coalingaensis at times, but is to be distinguished from the latter
by its thicker margin, less symmetrically elliptical petals wide open at the ends, its more con-
spicuous tubercles, and its less posteriorly excentric apex.

Localities —Near A. Kreyenhagen’s place and south of Lucile Well, 2 miles southwest of
Coalinga in Coalinga district, California.

Geologic horizon —Etchegoin formation, upper Miocene and lower Pliocene (7%).

* Collection.—U. 8. National Museum (165707).

DENDRASTER GIBBSIT (Rémond).

Plate LXXXIX, figs. la-b, 2-4; Plate CVIII, B.

Scutella gibbsii Rémond, 1863, California Acad. Sci. Proc., vol. 3, pp. 13, 14.

Scutella gibbsti Meek, 1864, Smithsonian Misc. Col., vol. 7 (183), p. 2.

Scutella gibbsii Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, pp. 37, 109, Pl. XIII, figs. 66, 66a.

Scutella gibbsit Cooper, 1888, Cat. California fossils, State Mineralogist Seventh Rept., p. 271.

Echinarachnius gibbsii Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 169, Pl. XXII,
fig. 7.

*Scutella gibbsii F. Anderson, 1905, California Acad. Sci. Proc., 3d ser., Geology, vol. 2, p. 180.

Echinarachnius ashleyi (Merriam, MS), Arnold, 1907, U. 8. Geol. Survey. Bull. 322, Pl. XXTV, figs. 6, 7.

?Echinarachnius excentricus Eschscholtz var. Arnold and Anderson, 1907, U. 8. Geol. Survey Bull. 322, Pl. XXIV,
fig. 8. This is apparently a somewhat variant form of Dendraster gibbsii.

Echinarachnius gibbsii Arnold, 1909 (pars), U. 8. Geol. Survey Bull 396, pp. 24, 25, 27, 31, 34 (pars); 38, 42 (pars), 132,
144, 146; Pl. XIII, figs. 1, 2; Pl. XIX, figs. 1, 2; Pl. XX, fig. 7.

non Echinarachnius gibbsii Arnold, 1909, (pars), U. 8S. Geol. Survey Bull. 396, pp. 34 (pars), 42 (pars), 162; Pl. XXVIII,
figs. 4, 4a.

Echinarachnius gibbsii Arnold and R. Anderson, 1910 (pars), U. S. Geol. Survey Bull. 398, pp. 316, 318; Pl. XLI, figs.
1, 2; Pl. XLII, fig. 7.

non Echinarachnius gibbsii Arnold and R. Anderson, 1910 (pars), U. 8. Geol. Survey Bull. 398, p. 338; Pl. L, figs. 4, 4a,

Dendraster ashleyi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706.

Dendraster gibbsii Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 704.

Determinative characters—Test small to large, suboblong, subquadrate, suboval, or sub-
ovate in marginal outline, length usually equal to or greater than width, though sometimes
considerably less, usually broadest back of the center; upper surface convex, much depressed,
though less so posteriorly than anteriorly, rising directly from the thin margin to the low,
posteriorly excentric apex; undersurface flat. Apical system very excentric posteriorly, from
one-third to more than one-half the radius from the center. Ambulacral petals large, all but
the odd petal approaching rather close to the margin; the posterior pair shorter than the others,
more divergent than the anteriorly curving anterior pair and with widely divergent poriferous
zones. Peristome small, excentric posteriorly, though less so than apical system; ambulacral
furrows fork near the peristome, the branches at first diverging then converging slightly and
proceeding nearly to the margin, giving off only a few branches. Periproct very small, cir-
cular, inframarginal, nearly marginal.

Dimensions —Specimen A (Pl. LXXXIX, figs. la, 1b): Length 62 millimeters; width 59
millimeters; height 13 millimeters. Specimen B (Pl. LXXXIX, fig. 2): Length 87 millimeters;
width 81 millimeters; height 11 millimeters. Specimen C (Pl. LX XXIX, fig. 3): Length 81
millimeters; width 95 millimeters; height 16 millimeters. Specimen D (Pl. LXXXIX, fic. 4):
Length 32 millimeters; width 33 millimeters; height 7 millimeters.

Description—A very good description of this interesting Californian species was given as
early as 1863 by Rémond. It was first figured by Gabb in 1869. The test is variable in size,
ranging from about 1 to 34 inches in diameter and from one-eighth to one-half inch in height.
In marginal outline it varies considerably, being usually suboblong or subquadrate; sometimes

194 ~ MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

suboval or subovate; length usually equal to or greater than width, though sometimes con-
siderably less, usually broadest back of the center but in front of the apical system. The upper
surface is somewhat irregularly convex; much depressed though less so posteriorly than ante-
riorly, rising directly from the margin to the low apex which is more or less posteriorly excen-
tric, sloping more steeply posteriorly than anteriorly. The margin is thin and is usually slightly
notched in the middle of the posterior end. The under surface is flat or slightly concave.

The ambulacral areas are wide, widest at the margin, where they are wider than the inter-
ambulacral areas; dorsal portions petaloid. The petals are large, the total area covered by
them being greater relatively than in most related forms; the anterior three longer than the pos-
terior two, the odd petal equal to or slightly longer than the anterior pair; all of them except
the odd petal approaching rather close to the margin. The anterior paired petals curve toward
each other, so as to be less divergent than the posterior pair, which are very short, widely
divergent, and have their anterior side the longer and their poriferous zones widely divergent.
The poriferous zones are of moderate width, those of the odd petal usually being narrower than
the rest; pores oval and conjugated. The interporiferous areas are wide, much wider than the
poriferous zones.

The interambulacral areas are very narrow between the petals, wide at the margin. The
surface of the test is covered with small uniform perforate tubercles which are slightly larger
on the under surface.

The apical system is very excentric posteriorly, being situated from one-third to more
than one-half the distance from the center to the posterior margin. The specimens which
are larger and more elongate longitudinally are those with the most excentric apical system.
The madreporite is large, subpentagonal, with four genital pores as the anterior points of the
pentagon, the two anterior nearer together than the two posterior. There are also five very
small radial plates each perforated by a minute pore.

The peristome is small, excentric posteriorly, though decidedly less so than the apical system.
The ambulacral furrows are simple and straight for a short distance from the peristome,
then fork nearly symmetrically into two strong furrows which diverge for a short distance,
then converge slightly and continue nearly to the margin. In young specimens they diverge
continuously to the margin. There do not appear to be many branches given off, though the
specimens are rarely sufficiently well preserved to show this feature.

The periproct is very small, circular or subcircular, inframarginal, nearly marginal, usually
1 or 2 millimeters from the inner edge of the sight notch in the posterior border.

Related forms.—Dendraster gibbsit is most closely related to D. eacentricus, but differs
from the latter in having its apex less central, its apical system more excentric, its posterior petals —
less widely divergent and with less widely divergent poriferous zones, and its periproct usually
somewhat nearer to the border. Some of the younger specimens of D. gibbsii also resemble
D. coalingaensis, but can be separated from it by its more excentric apical system, its less sym-
metrically elliptical ambulacral petals, and its more divergent posterior petals. No foreign
forms appear to be closely related to D. gibbsii. The Patagonian species Scutella patagonensis
Desor! resembles D. gibbsit in occurrence in two quite different forms, one longitudinally
elongate and one transversely elongate, which yet evidently belong to the same species, for
they grade into one another and they occur together.

Localities —Kern Lake, Buena Vista County (Rémond); near Buena Vista Lake, Kern
County (Gabb, Merriam); near Santa Cruz (Ashley); 8 miles north of Coalinga (Pl. LX XXIX,
figs. la, 1b); ridge south of Garcas County, Coalinga district (Pl. LAX XIX, figs. 2, 3); 10 to 12
miles southeast of northwest end of Kettleman Hills, Coalinga district (Pl. LX XXIX, fie. 4);
numerous other localities in Coalinga district (mcluding U.S. Geol. Survey localities Nos. 3849,
4751, 4753, 4755, 4757, 4767, 4768, and 4806); San Jacinto; Capitola (Pack); San Gregorio
(Pack); Graciosa Ridge near Orcutt, Santa Maria district, California.

1 See Reports of the Princeton University expeditions to Patagonia, 1896-1899, vol. 4, pt. 2, pp. 55-60; Pl. XI, figs. 4a, b, ¢, d, ©.

MIOCENE ECHINODERMATA. 195

Geologic horizon.—Jacalitos and Etchegoin formations, in Coalinga district, upper Miocene
and lower Pliocene (?). Fernando formation in Santa Maria district, upper Miocene or lower
Pliocene.

Collections —U. S. National Museum (165547, A; 165611, B, C; 165704, D); University
of California, California Academy of Sciences; Yale University.

DENDRASTER OREGONENSIS (Clark).

Plate XC, figure 1.

Scutella (Echinarachnius) oregonensis Clark, 1909, in Dall, U.S. Geol. Survey Prof. Paper 59, p. 140, Pl. VII, fig. 2.

Determinative characters.—Test small; subcircular in marginal outline, broader posteriorly
than anteriorly; the whole form greatly depressed, the upper surface moderately convex,
rising directly from the rather thin margin to the low, anteriorly excentric apex; under surface
flat. Apical system excentric posteriorly, about one-fourth the radius from the center. Ambu-
lacral petals relatively large, approaching rather close to the margin; the two posterior shorter
than the anterior three and with posterior poriferous zones straight or nearly so; open at their
ends. Peristome circular, subeentral. Ambulacral furrows feeble. Periproct small, sub-
circular, supramarginal.

Dimensions.—Length 20 millimeters; width 20 millimeters; height 3 millimeters.

Description.—This recently described Pacific coast Dendraster is one of the smallest
representatives of the genus, rarely exceeding an inch in diameter.

In marginal outline it is subcircular; though broader posteriorly than anteriorly. The
whole form is greatly depressed, the upper surface being evenly rounded and-rising directly
from the rather thin margin to the low apex which is situated forward of the center. The
under surface is flat or faintly concave.

The ambulacral areas are rather narrow; dorsal portions petaloid. The petals are rela-
tively large, approaching rather close to the margin, the two posterior shorter than the anterior
three, of which the odd petal is the longest. The petals are straight or nearly so, the anterior
pair shghtly more divergent than the posterior pair, and all are open at their ends. The
poriferous zones are broad, pores oval, pairs of pores conjugated; the posterior zones of both
pairs straight or nearly so. The interporiferous areas are narrow, about as wide or slightly
wider than the poriferous zones.

The interambulacral areas are broad, about equally so between the petals. The surface
of the test is closely set with small tubercles, apparently imperforate, set in deep scrobicules,
the tubercles being slightly larger on the under surface.

The apical system is excentric posteriorly, being situated about one-fourth the distance
from the center to the posterior border. The details could not be made out upon the specimens
studied.

The peristome is small, circular, subcentral; the ambulacral furrows feeble, not showing

very well upon the specimens; but apparently simple and straight for a short distance from
the peristome, then forking symmetrically.
The periproct is small, subcircular, supramarginal, about 1 millimeter from the posterior
ends. ,
_ Related forms.—D. oregonensis is closely allied to D. interlineatus, the superficial resemblance
being very striking, but differs in having all the petals open at the ends and the posterior and
anterior paired petals less symmetrically subelliptical in form by reason of the fact that the
posterior poriferous zones are straight or nearly so. D. oregonensis also differs m being relatively
higher in proportion to its width and has a relatively larger periproct. These differences are
not very pronounced, and further collecting may result in the merging of the two species.

Localities —Near Empire City and Fossil Point, Coos Bay, Oreg.

Geologic horizon.—Empire formation, upper Miocene.

Collection.—U. S. National Museum (153975).

196 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.
DENDRASTER COALINGAENSIS Twitchell, n. sp,

Plate XC, figures 2a-<.

Echinarachnius gibbsii Arnold, 1909, pars, U. 8. Geol. Survey Bull. 596, pp. 34 pars, 42 pars, 162; Pl. XXVIII, figs.
4, 4a.
Echinarachnius gibbsti Arnold, 1910, pars, U. 8. Geol. Survey Bull. 398, p. 338, Pl. V, figs. 4, 4a.

Determinative characters.—Test small; broadly ovate in marginal outline; broadest about
opposite or to the rear of the apical system; upper surface convex, greatly depressed though
less so posteriorly than anteriorly, arising directly from the thin margin to the apex which is
excentrie posteriorly and about coincident with the apical system; under surface concave
around the peristome. Apical system excentric posteriorly, about one-fourth the radius from
the center. Ambulacral petals wide, straight and symmetrically subellipical; the posterior
pair shorter than the others, and usually less divergent than the anterior pair. Peristome
small, slightly excentric posteriorly; ambulacral furrows simple and straight for about one-
third the radius, then forking, each pair of branches diverging continuously nearly to the margin,
where they split into several small branches. Periproct small, circular, inframarginal, almost
marginal.

Dimensions.—Length 33 millimeters; width 31 millimeters; height 5 millimeters. One of
the smallest specimens studied was only 14 millimeters in diameter.

Description.—This small Dendraster is found in association with D. perrini in the Coalinga °
district, California, whence the name given. A number of specimens were collected and one
was figured by Arnold. The test is small, ranging from one-half to 14 inches in diameter;
broadly ovate in marginal outline, broadest opposite or slightly to the rear of the apical system.
The upper surface is somewhat irregularly convex, greatly depressed, though less so posteriorly
than anteriorly, rising directly from the margin to the low, posteriorly excentric apex. The
margin is thin.

The ambulacral areas are wide, widest at the margin, where they exceed the interambu-
lacral areas in width; dorsal portions petaloid. The petals are cf medium length, wide, straight,
and symmetrically subelliptical, wide open at the ends; the anterior three longer than the pos-
terior two, the odd petal slightly longer than the anterior pair; the posterior pair usually less
divergent, sometimes about as equally divergent as the anterior pair. The poriferous zones
are wide, outer row of pores subelliptical, inner row subcircular; pairs of pores conjugated. The
interporiferous areas are wide, and slightly tumid.

The interambulacral areas are narrow between the inner ends of the petals, wide from the
outer ends of the petals to the margin, each area of about equal width with the others. The
surface of the test is covered with small, uniform, perforate tubercles in deep scrobicules. The
tubercles and scrobicules are slightly larger on the under surface and larger than in related :
forms.

The apical system is excentric posteriorly, being situated about one-fourth the distance
from the center to the posterior border and coincident or very nearly coincident with the apex.
There is a large pentagonal madreporite, four genital pores of which the anterior pair are nearer
together than the posterior pair; and five ame radial plates each perforated by a minute pore.

The peristome is small, subcircular, slightly excentric posteriorly, but slightly less so than
the apical system. The annibclaerall eamorTe are simple and straight for about one-third the
way to the margin, then fork symmetrically, each pair of branches diverging continuously to
near the margin where they split into several small branches. i

The periproct is small, circular, inframarginal, almost marginal, usually less than a milli-
meter from the posterior edge.

Related forms.—D. coalingaensis is closely related to D. excentricus, of which it may be an
ancestral form. It differs from the latter, however, in being much smaller and less tumid
centrally, in having its apex less central and more nearly coincident with the apical system,
and in having its periproct nearer to the margin. D. coalingaensis also closely resembles D.
gibbsii, especially the young specimens of the latter species, but can be readily separated by its

MIOCENE ECHINODERMATA, 197

much less excentric apical system, its more symmetrically elliptical ambulacral petals, and the
fact that its posterior petals diverge less widely and also have poriferous zones which are less
widely divergent at their ends and more equalin length. Some specimens of D. arnoldi resemble
D. coalingaensis; but they have thicker margins, more widely open ambulacral petals, more con-
spicuous tubercles, more tumid interporiferous areas, and a central apex which is also not coin-
cident with the apical system.

Localities.—Near A. Kreyenhagen’s place (type), and 1,244-foot hill 4 miles southeast of
northwest end of Kettleman Hills, in Coalinga district, California.

Geologic horizon.—Etchegoin formation (apparently limited to the upper portion of the
formation), upper Miocene and lower Pliocene (7).

Collection.—U. 8. National Museum (165537).

DENDRASTER sp. (Conrad).

Scutella sp. Conrad, 1857, U. S. Pacific R. R. Expl., vol. 7, Pl. X, figs. 3, 4; no description.
Dendraster sp. Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 704.

As Conrad gave no description of this form its exact relationships can not be determined
with certainty. It resembles Dendraster interlineatus in some respects, but not closely enough
to justify its identification with that species.

EcHINARACHNIUS sp. Conrad.

Echinarachnius sp. Conrad, 1857, U. S. Pacific R. R. Expl., vol. 7, Pl. IX, fig. 5; no description.
This is only a poor figure of an imperfect specimen, unaccompanied by a description. It
is not entitled to recognition and the exact relationships can not be determined from such data.

Genus ASTRODAPSIS Conrad (amended).

Astrodapsis Conrad, 1869, Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 315.
Astrodapsis Conrad, 1857, U. S. Pacific R. R. Expl., vol. 7, Pal. Rept., p. 196.
Astrodapsis Rémond, 1863, California Acad. Nat. Sci. Proc., vol. 3, p. 52.

The writer does not agree with Duncan? in regarding Conrad’s genus Astrodapsis as a
synonym of Breynius’s genus Arachnoides. The inframarginal position of the periproct,
the depressed apical system, and the elevated ambulacral areas alternating with depressed
interambulacral areas sufficiently distinguish Astrodapsis from Arachnoides.

Conrad’s description of his genus is as follows: “Suboval; depressed; ambulacral areas
elevated or ridged; ambulacra nearly straight, widely open at the extremity; mouth central;
anus submarginal, beneath; radiating grooves as in Laganum.” This description was good
in view of the small amount of material Conrad had, but it now becomes necessary to redraw
the diagnosis of the genus in order to make a few emendations.

Description.—Test depressed, subdiscoidal to broadly subconical in general form, circular
to subelliptical in marginal outline, margin varying from thin to very thick, with or without
notches opposite the ambulacral petals. Ambulacral areas elevated or ridged; interambula-
cral areas depressed. Ambulacral petals straight, extending nearly to the margin, widely open
at the ends; poriferous zones nearly parallel, continuously diverging, or diverging, converging,
and again diverging. Apical system more or less depressed. Peristome central or subcentral.
Main ambulacral grooves simple and straight from peristome to margin, continuing as fainter
grooves or processes over the margin and along the middle of the ambulacral ridges nearly to
the apical system; two faint lines or processes are given off from the main grooves from one-
half to two-thirds the way to the margin, which continue over the margin and along the upper
surface between the tops of the ambulacral ridges and the bottoms of the ambulacral depres-
sions nearly to the apical system. Periproct small, inframarginal, almost marginal.

1 Duncan, P. M., Revision of genera and great groups of the Echinoidea: Linn, Soe. Jour. Zoology, vol. 23, p. 165, 1891.

198 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

ASTRODAPSIS ANTISELLI Conrad.
Plate XCIV, figures 3, 4a-b.

Astrodapsis antiselli Conrad, 1856, Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 315; no figures.

Astrodapsis antiselli Conrad, 1857, U. 8. Pacific R. R. Expl., vol. 7, p. 196, Pl. X, figs. 1, 2.

Astrodapsis antiselli Meek, 1864, Smithsonian Mise. Coll., vol. 7 (183), p. 2.

Astrodapsis antiselli Gabb, 1869, California Geol. Survey Rept., Paleontology, vol. 2, p. 110.

Astrodapsis antiselli Cooper, 1888, State Mineralogist California Seventh Rept., p. 270.

Astrodapsis antiselli Arnold, 1908, U. 8. Nat. Mus. Proc., vol. 34, Pl. XX XV, fig. 10; no description.

Astrodapsis antiselli Arnold, 1909, U. S. Geol. Survey Geol. Atlas, Santa Cruz folio (No. 163), Pl. II, fig. 58.

non Astrodapsis antiselli var. arnoldi Pack, 1909, Uniy. California Dept. Geology Bull., vol. 5, No. 18, pp. 279-281, Pl.
XXIV, figs. 1, 2. See Astrodapsis arnoldi.

Astrodapsis antiselli Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 702.

Determinative characters.—Test medium in size; regularly oval in marginal outline, longer
than broad, slightly truncated at anterior end, slightly poimted at posterior end, with faint
notches opposite ends of petals; margin rounded and very thick, almost as thick as rest of
test. The whole form is considerably depressed, almost equally so from edge to edge, and
therefore subdiscoidal; the upper surface with broad, flattened ambulacral ridges alternating
with narrow Pavone wolleerell depressions; apex excentric anteriorly, in roms of dlsonesecil
apical system; lower surface slightly concave. Ambulacral petals large, broad, tumid, espe-
cially near apical system; poriferous zones narrow, at first diverging, then ours dishily
from one-fourth to one-third the way to the margin, and again diverging to the wide-open ends
which are nearly at the margin. Peristome central; the main anibulaced grooves straight,
well defined, and rather deep from peristome to margin and continuing as faint lines over
margin to near apex, two faint lines are given off about halfway to margin, which continue
over margin to near apical system. Periproct small, inframarginal, sileaesth marginal.

Dimensions—Specimen B: Length 57 millimeters; width 50 millimeters; height 14
millimeters.

Description.—This species was one of the first of the Tertiary echinoids to be reported
from the Pacific coast of the United States, having been described by Conrad as early as 1856.
Conrad founded his new genus Astrodapsis upon this species. The test is medium in size,
averaging about 2 inches in length. In marginal outline it is regularly oval, longer than
broad, usually slightly truncated at the anterior end and somewhat pointed at the posterior
end, with very slight notches opposite the ends of the petals; margin rounded and very thick,
almost equal in Aid anese to the rest of the test, somewhat thicker anteriorly than poste-
riorly. The whole form considerably depressed, Subdiscoidall ; the upper surface with broad
flattened ambulacral ridges alternating with narrow interambulacral depressions; apex excen-
tric anteriorly in front of apical system; under surface slightly concave.

The ambulacral areas are wide; dorsal portions petaloid. The petals are large, broad,
tumid, widest and most tumid near the apical system, constituting broad ridges, all of them
extending nearly to the margin, wide open at the ends; interporiferous areas very wide; porif-
erous zones narrow and of nearly equal breadth throughout their length, at first diverging,
then converging slightly from one-fourth to one-third the way from the margin, and again
diverging; inner row of pores round, outer row broadly slitlike, pairs of pores conjugated.

The interambulacral areas are narrow, decidedly depressed, forming radial grooves in
the upper surface. The whole surface of the test is covered with small but conspicuous
tubercles, which make the surface feel rough; they are larger and more conspicuous in the
interporiferous areas.

The apical system is slightly excentric anteriorly, in a star-shaped depression below the
level of the ambulacral ridges. There appear to be only four genital pores which are located
at four of the points of the star-shaped depression. No further details could be made out.

The peristome is central, circular to subpentagonal. The main ambulacral grooves are
straight, well defined and rather deep from peristome to margin and continue as faint lines over
the margin and along the middle of the ambulacral ridges to the apical system; two faintly

MIOCENE ECHINODERMATA, 199

defined processes are given off about halfway from the peristome to the margin, which extend
to and over the margin and on the upper surface between the top of the ridges and the bottom
of the depressions, becoming indistinct as the apical system is approached.

The periproct is small, subcircular, inframarginal, almost marginal.

Related forms.—Duncan' regarded Conrad’s genus Astrodapsis as a synonym of Breynius’s
genus Arachnoides; but, though there are certain poimts of resemblance, the inframarginal
position of the periproct, the more or less depressed apical system and the elevated, ridgelike
ambulacral areas alternating with depressed groovelike interambulacral areas on the upper
surface would appear to sufficiently differentiate the genus Astrodapsis.

The present species is readily separated from the other representatives of the genus,
although some confusion has arisen in the literature and in various collections because of the
obscure location of Conrad’s description and figures. A. whitneyi differs in being broadly sub-
conical and in having a thin margin, more circular outline, more pronounced marginal notches,
higher ambulacral ridges and deeper interambulacral depressions. A. twmidus differs in being
smaller and in having a greater difference between the height of the ambulacral ridges and
interambulacral depressions.

Localities —Monterey County (type), and 2 miles south of San Lucas, Monterey County
(specimen B), Cal. Conrad also cites Estrella, and Gabb gives near Buena Vista Lake, both in
‘California.

Geologic horizon.—Santa Margarita formation, middle or upper Miocene.

Collection.—U. S. National Museum (165466, A; 165466a, B). (Both the type and the
specimens collected by Arnold, which include specimens A and B.)

ASTRODAPSIS ARNOLDI Twitchell, n. sp.
Plate XCV, figure 1.

Astrodapsis whitneyi Arnold, 1909, U. S. Geol. Survey Bull. No. 396, p. 63, Pl. XT, fig. 1.

Astrodapsis antiselli var. arnoldi Pack, 1909, California Univ. Dept. Geology Bull., vol. 5, No. 18, pp. 279-281, Pl.
XXIV, figs. 1, 2.

Astrodapsis whitneyt Stefanini, 1911, pars, Soc. geol. italiana Boll., vol. 30, p. 703.

Determinative characters.—Test large, larger than most representatives of the genus; circu-
lar in marginal outline; margin and wide submarginal area notably thin, undulating, with pro-
nounced posterior notches and less pronounced anterior notches. The whole form considerably
depressed, greatly and nearly equally so for half the distance from margin toward the center, |
moderately elevated centrally, with rather broad and somewhat flattened ambulacral ridges
alternating with broad deep interambulacral depressions. The inner ends of the ambulacral
ridges almost coalesce around the slightly depressed apical system and form the somewhat
flattened subcentral apex of the test. Lower surface flat or nearly so. Petals moderately
wide, elongate subelliptical, nearly reaching the margin where wide open; inner halves elevated
and tumid, outer halves depressed and merging with submarginal area; inner rows of pores
of each petal nearly parallel for most of their length. Peristome small, circular, central; main
ambulacral grooves simple, straight and deep to the margin, continuing as faint lines straight
and deep over margin and along middle of ambulacral ridges nearly to apex; two faint processes
are given off about half way to margin which continue over margin and on upper surface to near
the apex. Periproct very small, inframarginal, almost marginal.

Dimensions.—Length 76 millimeters; width 75 millimeters; height 10 millimeters.

Description.—The test of this new Astrodapsis is unusually large. In marginal outline it
is circular; the margin is markedly thin, undulating, with well-defined notches opposite the
ends of the petals, the posterior notches being slightly larger than the anterior pair, which are
larger than the odd one; the submarginal area for nearly half the way toward the center is also
thin, about as thin as at the margin. Centrally, within the area circumscribed by the thin and
flattened submarginal area, the upper surface is moderately elevated with rather broad and

1 Duncan, P. M., Revision of genera and great groups of the Echinoidea: Linn. Soc. Jour. Zoology, vol. 23, p. 165, 1891.

200 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

somewhat flattened ambulacral ridges alternating with broad deep interambulacral depressions,
the central elevation being flattened on top around the slightly depressed apical system. The
ambulacral ridges almost coalesce around the apical system. The apex is central or subcentral;
the lower surface flat or but very slightly concave from margin to centef.

The ambulacral areas are wide, slightly wider at the margin than the interambulacral areas,
narrowing rapidly to a point about midway between the margin and the center of the test,
where narrower than the interambulacral areas; dorsal portions petaloid. The petals are of
moderate width, elongate subelliptical, long, nearly reaching the margin, the inner half of
each petal elevated, tumid but somewhat flattened on top, the outer half depressed, gradually
broadening and merging with the flattened submarginal area; the poriferous zones are narrow,
the inner rows of pores nearly straight and parallel for most of their length, wide apart at the
ends, composed of large, round openings; outer rows diverging for about half the distance to
the margin then drawing near inner rows, pores slitlike; pairs of pores conjugated. The sur-
face of the odd petal is slightly higher than that of the anterior pair, which is shghtly higher
than that of the posterior pair.

The interambulacral areas at the margin are somewhat narrower than the ambulacral
areas, near the apex they are much narrower, almost obliterated; they become depressed rather
rapidly from near the apex to about halfway to the margin, whence they merge with the flat-
tened submarginal area, though keeping slightly more depressed than the adjacent ambulacral
areas. The surface of the test is covered with small but rather conspicuous tubercles, most
conspicuous in the interporiferous areas. ;

The apical system is central, slightly depressed below the top of the ambulacral ridges.
The details could not be made out on the specimen studied.

The peristome is small, circular, central. The main ambulacral grooves are simple, straight,
and deep from peristome to margin; they continue as faint lines over the margin, and along
the middle of the ambulacral ridges nearly to the apex; two faintly defined processes are
given off about halfway from peristome to margin which extend to and over the margin and
along the upper surface between the top of the ridges and the bottom of the depressions, near
the suture line between the ambulacral and interambulacral plates, disappearing near the
inner ends of the interambulacral depressions.

The periproct is very small, inframarginal, almost marginal.

Related forms.—A. arnoldi is most closely related to A. whitneyi. In fact specimens of
each species answer to Rémond’s description, and in view of the loss of Rémond’s type it is
not possible to be sure which form was really his. Merriam, evidently influenced by Gabb’s
figure, and before Arnold’s and Pack’s specimens were discovered, redescribed and figured as
A. whitneyi the broadly subconical form. Arnold’s specimen, with the arch of the upper sur-
face commencing some distance in from the edge, was identified by him as an Astrodapsis
whitneyi. Pack describes and figures a specimen which is evidently identical with that of
Arnold just referred to but errs in treating it as a variety of A. antiselli, from which it differs
considerably, in fact, much more than it does from the A. whitney: of Gabb and Merriam.
The present form, represented by the specimens of Arnold and of Pack, appears to be entitled
to recognition as a distinct species, and as the writer agrees with Merriam in regarding the
broadly subconical form figured by Gabb as most probably Rémond’s A. whitney the present
species is named after Arnold, who collected the type in the Coalinga district, California.
A. arnoldi is readily distinguished from A. whitneyi in having the arch of the upper surface
commencing almost halfway in from the edge, the margin and wide submarginal area being
notably ‘thin, also in having the outer portions of the petals greatly depressed and merging
with the submarginal area, and the ambulacral ridges somewhat broader and more flattened
near the apex. A. anfiselli has a much thicker margin and is subdiscoidal in form besides
differing in other ways. A. jacalitosensis has its apical region much more depressed, and into
this depression extend the interambulacral depressions; the odd petal is higher and more con-
spicuous and the inner lines of pores of the petals diverge instead of being nearly parallel.

MIOCENE ECHINODERMATA, 201

Localities.—Above Big Blue, west of Peerless Oil property, 9 miles north of Coalinga
(type), and Salinas Valley, Monterey County, Cal.

Geologic horizon.—Santa Margarita formation, middle or upper Miocene.

Collections. —U.S. Nationai Museum (165594); University of California.

ASTRODAPSIS WHITNEYI Rémond.
Plate XCV, figures 2a-c.
Astrodapsis whitneyi Rémond, 1863, California Acad. Nat. Sci. Proc., vol. 3, p. 52; no figure.
Astrodapsis whitneyt Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.
Astrodapsis whitneyt Gabb, 1869, California Geol. Survey Rept., Paleontology, vol. 2, pp. 37, 110, Pl. XIII, figs. 67, 67a.
Astrodapsis whitneyt Cooper, 1888, State Mineralogist of California Seventh Rept., p. 271.
Astrodapsis whitneyi Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 167, Pl. XXT, figs.
4, 4a.
non Astrodapsis whitneyi Arnold, 1909, U. 8. Geol. Survey Bull. 396, p. 63, Pl. XI, fig. 1. See Astrodapsis arnoldi.
Astrodapsis whitneyt Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Determanative characters.—Test medium to large; circular in marginal outline, broadly
subconical in general form; margin thin, with small subequal ambulacral notches. Upper sur-
face rising directly from margin to the relatively high, slightly anteriorly excentric apex; with
high, narrow, steep-sided ambulacral ridges alternating with broad, deep interambulacral
depressions. Lower surface concave. Petals relatively narrow, elongate subelliptical, nearly
reaching margin, wide open at ends; inner rows of pores nearly parallel for most of their length.
Apical system slightly excentric anteriorly, faintly depressed below top of petals. Peristome
central; main ambulacral grooves simple, straight, and deep to the margin, continuing as faint
lines on upper surface nearly to apex; two faint processes given off about halfway to margin,
which also continue to and over margin and on upper surface nearly to apex. Periproct small,
subcircular, inframarginal, almost marginal.

Dimensions.—Length 50 millimeters; width 50 millimeters; height 13 millimeters.

Description.—This species was one of the first fossil echinoids to be reported from the
California Tertiary deposits, having been described, but not figured, by Rémond in 1863. The
test is medium to large, ranging, according to Merriam, up to 65 millimeters in diameter. In
marginal outline it is circular; margin thin, with small but well-defined, subequal notches oppo-
site all the ambulacral petals. The whole form is depressed, but less so than in related species,
the upper surface being broadly subconical, rising directly from the margin to the relatively
high, slightly anteriorly excentric apex; with high, narrow, steep-sided ambulacral ridges alter-
nating with broad, deep, interambulacral depressions. The under surface is concave, the con-
cavity gradually deepening to the peristome, where it is about one-third of the height of the
test.

The ambulacral areas are wide, wider than the interambulacral areas; dorsal portions
petaloid. The petals are relatively narrow, elongate subelliptical, long, nearly reaching the
margin; the poriferous zones are narrow, about half as wide as the tumid interporiferous areas,
the inner rows of pores elevated, nearly straight, and parallel for most of their length, wide apart
at the ends, composed of large, round openings; outer rows depressed, diverging for about half
the distance to the margin, then drawing near the inner rows, pores slitlike; pairs of pores con-
jugated; several pairs of pores occur beyond and diverge from the ends of the petals.

The interambulacral areas at the margin are somewhat narrower than the ambulacral areas;
near the apex they are much narrower, almost obliterated; they are gradually depressed from
near the apex to the margin. The surface of the test is covered with small, inconspicuous
tubercles, varying in size and set in shallow scrobicules; the tubercles are somewhat larger in
the interporiferous areas than elsewhere.

The apical system is shghtly excentric anteriorly, faintly depressed below the tops of the
ambulacral petals. The details could not be made out on the specimen.

The peristome is central. The main ambulacral grooves are simple, straight, and deep
from peristome to margin; they continue as fainter lines over the margin and along the middle

202 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

of the ambulacral ridges nearly to the apex; two faintly defined processes are given off about
halfway from peristome to margin, which extend to and over the margin and on the upper
surface between the tops of the ridges and bottom of the depressions.

The periproct is very small, subcircular, inframarginal, almost marginal.

Re ‘ As the location of the type is unknown, some doubt exists as to the exact
form which should be called A. whitneyi. The species described under the name of A. arnold
(p. 199) agrees with Rémond’s description of A. whitneyt as well as if not slightly better
than that described and figured by Merriam as A. whitneyi, which is here adopted. However,
Gabb figured as A. whitneyi a specimen similar to the present form, and the writer here follows
Merriam in regarding it as probably similar to Rémond’s original form. A. whitneyt is most
closely related to A. arnoldi, which differs in having the arch of the upper surface commence
nearly halfway in from the margin to the center, in having a markedly thin margin and submar-
ginal area, and the outer half of each petal greatly depressed and merging with the submarginal
area. A. whitney? is also closely related to A. jacalitosensis, which differs in much the same way
as A. arnoldi, and further in having a more deeply depressed apical system, the interambulacral
depressions extending to and joining the apical depression, and the inner line of pores of the
petals diverging. A. whitneyiis also allied to A. tumidus, which is smaller, has a thicker margin,
and a less definitely broadly, subconical upper surface.

Localities —Kirkers Pass, north of Mount Diablo, and south shore of San Pablo Bay, Cal.

Geologic horizon.—San Pablo formation (upper part), upper Miocene.

Collection.—University of California (19426).

ASTRODAPSIS TUMIDUS Rémond.
Plate XCV, figures 3a—b; Plate CVIII, A.

Astrodapsis tumidus Rémond, 1863, California Acad. Nat. Sci. Proc., vol. 3, pp. 52, 53; no figure.

Astrodapsis tumidus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Astrodapsis tumidus Gabb, 1869, California Geol. Survey Rept., Paleontology, vol. 2, pp. 37, 110, Pl. XIII, figs. 68, 68a.
Astrodapsis tumidus Cooper, 1888, State Mineralogist of California Seventh Rept., p. 270.

Astrodapsis tumidus Merriam, 1899, California Acad. Sci. Proc., 3d ser., vol. 1, No. 5, p. 166, Pl. X XI, fig. 3.
Astrodapsis tumidus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Determinative characters.—Test small, circular to oval in marginal outline; margin thick,
especially opposite petals, faintly notched opposite petals. Whole form, greatly depressed;
upper surface slightly and more or less regularly convex from edge to edge, with high, moder-
ately wide ambulacral ridges alternating with rather narrow imtionemelbrllvoual depressions. The
ridges are conspicuous for two-thirds the way from center to margin, then become nearly flush
with the adjacent surfaces; the depressions extend down the middle of the interambulacral
areas from apex to margin, widening between the petals. Apex low, subcentral; under surface
slightly concave. Petals wide in proportion to length, subelliptical, nearly reaching the margin;
poriferous zones about one-third width of tumid interporiferous areas, inner row of pores ele-
vated, outer row depressed. Apical system subcentral, slightly depressed below tops of petals.
Peristome small, circular, subcentral; main ambulacral grooves simple, straight, and deep to
margin, continuing over margin and nearly to apex as a faint line. Periproct very small, cir-
cular, inframarginal, almost marginal.

Dimensions.—Length 30 millimeters; width 30 millimeters; height 8 millimeters.

Description.—This species is one of the earliest reported Pacific coast fossil echinoids, having
been described, but not figured, by Rémond in 1863. The test is small, rarely exceeding 14
inches in diameter. In marginal outline it is somewhat variable, though rasa oval or circu-
lar; margin moderately Enlok and rounded, quite thick opposite the ends of the petals, where
equal to more than half the height of the test, with faint notches opposite the ends of the petals.
The whole form is greatly depressed; the upper surface slightly and more or less regularly convex
from edge to edge, with high, moderately wide ambulacral ridges, which are conspicuous for
two-thirds of the way from the center, alternating with rather narrow, deep, interambulacral
depressions. The apex is-low, subcentral; under surface slightly concave.

MIOCENE ECHINODERMATA, 208

The ambulacral petals are relatively wide in proportion to their length, subelliptical,

nearly reaching the margin, wide open at the ends, inner two-thirds or more tumid and promi-
nent, outer ends nearly flush with the adjacent surfaces; poriferous zones narrow, about one-
third the width of the interporiferous areas; the inner row of pores elevated, pores round,
outer row depressed, pores slitlike, pairs of pores conjugated.

The interambulacral areas are deeply depressed along the middle from apex to margin.
The surface of the test, including the margin and interporiferous areas is covered with small,
conspicuous tubercles in deep scrobicules.

The apical system is subcentral, slightly but distinctly depressed below the tops of the
petals. The details could not be made out on the specimen.

The peristome is small, circular, subcentral. The main ambulacral grooves are simple,
straight, and deep from peristome to margin, continuing as faint lines over the margin and
along the ambulacral ridges nearly to the apex. The two faint processes usually given off
from the main grooves on species of this genus could not be clearly made out on the specimen
studied.

The periproct is very small, circular, inframarginal, almost marginal.

Related forms.—A. tumidus is most closely related to A. whitneyi, but has a thicker margin,
especially opposite the ends of the petals, is, in general, smaller, lower, and not subconical, has
only faint marginal notches, petals which are broader in proportion to their length, a more
depressed apical system and a less concave lower surface. A. tumidus presents some features
similar to A. antiselli, which make descriptions sound alike; but the forms are quite distinct,
A. tumidus being readily distinguished by its smaller size, less thickness, much narrower and
higher ambulacral ridges, and wider interambulacral depressions.

Localities—Kirkers Pass and 2 miles west of Walnut Creek House (Rémond); San Pablo
Bay, Cal. (Merriam).

Geologic horizon.—San Pablo formation (middle part), upper Miocene.

Collection.—University of California (19424).

ASTRODAPSIS JACALITOSENSIS Arnold.

Plate XCV, figure 4.

Astrodapsis jacalitosensis Arnold, 1909, U. S. Geol. Survey Bull. 396, pp. 63-64, Pl. XV, fig. 5.
Astrodapsis jacalitosensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 703.

Determinative characters—Test large; broadly subovate in marginal outline, broadest
posteriorly; margin thin, deeply notched opposite the posterior petals. The whole form con-
siderably depressed, greatly and equally so for half the way in from edge; centrally the upper
surface is higher, with conspicuous ambulacral ridges, of which the odd anterior one is the
highest, thus forming the anteriorly excentric apex of the test, and pronounced interambu-
lacral depressions which merge with the deep depression in the apical region, the posterior
depression being deeper and narrower than the rest. Petals tumid and elevated proximally,
depressed distally; inner rows of pores diverging in nearly straight lines to near the margin,
where wide apart outer row curving at first away from and then toward the inner row. Apical
system excentric anteriorly, deeply depressed. Details of lower surface could not be made
out. Periproct small, inframarginal, almost marginal.

Dimensions.—Length 77 millimeters; width 74 millimeters; height 15 millimeters.

Description.—This new Astrodapsis, which Arnold regards as a characteristic fossil of the
Jacalitos formation in California, is large in size, being one of the largest representatives of the
genus. In marginal outline it is broadly subovate, broadest posteriorly, slightly longer than
wide, with deep notches opposite the posterior petals and faint notches opposite the other
petals; margin thin. The whole form is considerably depressed, the marginal and submargi-
nal areas greatly so and about evenly so all around. Within the imner portion of the petaloidal
region there are alternating ambulacral ridges and interambulacral depressions. The depres-
sions extend to and merge with the deep depression in the apical region, the posterior depression

204 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

being deeper, narrower, and more pronounced than the rest. The ridges are all conspicuous,
but the odd anterior one is the highest and most pronounced, constituting the anteriorly excen-
tric apex of the test. The details of the under surface could not be made out on the specimen.

The ambulacral areas are wide, slightly wider than the interambulacral areas at the mar-
gin; dorsal portions subpetaloid. The inner parts of the peatals are tumid and elevated,
the outer parts depressed. The inner rows of pores gradually and continuously diverge to about
one-fourth inch from the margin. The outer rows first diverge and then converge around the
tumid parts of the petals and approach near to the imner row, beyond which point both rows
diverge slightly to the margin. The inner rows of pores are large and round, the outer rows
oval. There are one or two extra rows of pores within the main inner row. The pairs of pores
are conjugated.

The apical system is excentric anteriorly, decidedly depressed below the surface of the
petals. The details could not be made out.

The under surface not being exposed the details in regard to the peristome and ambulacral
grooves can not be given. The periproct is small, inframarginal, almost merginal.

Related forms.—A. jacalitosensis is most closely related to A. arnoldi, which differs in
having a less depressed apical region and not having the interambulacral depressions continu-
ing to and joining the apical depression; also in having the inner rows of pores of each petal
nearly parallel.

Locality.—South of Garza Creek, a mile southeast of Clark’s place, Coalinga district, Cal.

Geologic horizon.—Jacalitos formation, upper Miocene.

Oollection.— U.S. National Museum (165610).

Genus MELLITA Agassiz.
MELLITA CAROLINIANA Ravenel.
Plate XCI, figures la-b; Plate XCII, figures la—b.

Scutella caroliniana Ravenel, 1841, Acad. Nat. Sci. Philadelphia Jour., Ist ser., vol. 8, pp. 333, 334, text figure.
non Mellita hexapora L. Agassiz, 1841, Mon. échinodermes vivans et fossiles; Des scutelles, p. 41, Pl. IV, figs. 11, 12.
Mellita caroliniana Ravenel, 1848, Echinid, recent and fossil, of South Carolina, p. 160.

Scutella carolinensis Tuomey, 1848, Geology South Carolina Rept., p. 208.

Mellita caroliniana Ravenel, 1850, Nae, Assoc. Ady. Sci. Proc., vol. 3, p. 160.

Mellita caroliniana Tuomey and Holmes, 1855, Pllocene foes South Carolina, pp. 3, 4, Pl. I, ae 2

non Mellita hexapora Desor, 1858, Synopsis des échinides fossiles, p. 237.

Mellita caroliniata Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Mellita caroliniana Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74

Mortonia (Periarchus) carolinensis Conrad, 1866, Smithsonian Misc. Coll., vol. 7 (200), p. 21.

non Mellita sexforis, A. Agassiz, 1872, Revision of the Echini, pp. 141, 320.

non Mellita sexforis Gregory, 1891, Geol. Soe. America Bull., vol. 3, p. 107.

Scutella caroliniana Boyle, 1893, U. 8. Geol. Survey Bull. 102, p. 262.

Periarchus carolinensis ? Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 699.

Mellita caroliniana Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 708.

Determinative characters.—Test small to very large; subcircular to subpentagonal in mar-
ginal outline, broadest between the anterior and posterior pairs of petals; six lunules, the odd
posterior one much longer than the posterior pair which are longer than the rest; margin thin;
the whole form greatly depressed, the upper surface rising gradually and but slightly from the
margin to the very low, subcentral or posteriorly excentric apex; under surface flat. Ambu-
lacral petals large, the posterior pair longer than the others. Apical system excentric ante-
riorly. Peristome small, subcircular, excentric anteriorly; ambulacral furrows simple and
straight near the peristome, then forking, each pair of branches diverging and again converging
near the margin. Periproct very small, elliptical, between the imner end of the odd posterior
lunule and the peristome.

Dimensions.—The large form figured gave: Length 159 millimeters; width 152 millimeters;
height about 10 millimeters.

MIOCENE ECHINODERMATA. 205

Description.—This beautiful Mellita, first reported and described by Ravenel in 1841, is
probably the oldest representative of the genus, as it undoubtedly existed in America in Mio-
cene time. Hitherto the genus has not been positively known to have existed prior to the
Pliocene. The species is rather rare, only a few specimens having been reported up to the
present time. The test is small to very large in size, ranging from 1 to 6 inches in diameter.
In marginal outline it is somewhat variable, being either subcircular, subpentagonal, or broadly
subovate. It is usually about as long as broad; broadest between the anterior and posterior
pair of petals, usually about the middle, but sometimes back of the middle of the test; rounded
or truncated posteriorly. There are six lunules, one opposite each petal and very near the
margin and one in the middle of the posterior ambulacrum, distant from the margin. The
three anterior lunules are short and either pyriform or narrowly oblong, the posterior pair
longer and usually narrowly oblong, and the odd posterior one much longer and frequently
wider than all of the others, and either narrowly oblong or elongate subpyriform or elongate
subelliptical. In young specimens the odd posterior lunule is much longer and more con-
spicuous relatively than in older ones. The whole form is greatly depressed, the upper surface
rising gradually from the margin to the very low apex which is either central, slightly excentric
anteriorly or excentric posteriorly, and rarely rises to a height of half an inch in even the largest .
specimens. The margin is thin, sometimes with faint notches opposite the posterior paired
petals. The under surface is flat, or nearly so.

The ambulacral areas are relatively narrow in the petaloid dorsal portions, wide between
the ends of the petals and the margin where they are wider than the interambulacral areas,
narrowing again at the margin. The petals are large, and somewhat variable, extending half-
way cr decidedly more or less than halfway to the margin; subelliptical to subspatulate in form;
usually narrower than those of Mellita pentapora; the posterior pair longer than the others,
which are subequal in length. The poriferous zones are broad, equal to or broader than the
interporiferous areas; pores oval, pairs of pores conjugated by very narrow, flexuous grooves.

The interambulacral areas are broad, broadest at the margin, where they are wider than
the ambulacral areas. The surface of the test is closely set with very small, imperforate
tubercles, set in deep scrobicules. The tubercles are larger on the under surface except along
and near the ambulacral furrows.

The apical system is excentric anteriorly, large and stellate; four genital pores at the tips
of the points of the star, the two posterior farthest apart; five small pores at the inner ends of
the reentrant angles of the star.

The peristome is small, subcircular, excentric anteriorly; the ambulacral furrows simple
and straight near the peristome, then forking, each pair of branches diverging and again con-
verging near the margin so as to surround the lunules.

The periproct is very small, elliptical, between the inner end of the odd posterior lunule
and the peristome.

Related forms.— M. caroliniana is closely related to IM. pentapora, which is readily sepa-
rated by its having only five lunules, by the greater height and more antericr position of its
apex, and by having its lunules subequal in length and farther from the margin. JL. caroliniana
is still more closely related to the recent species J. sexforis A. Agassiz, which, however, differs
in having its five ambulacral lunules all of the same length and its odd posterior lunule a little
shorter than the others; another difference is that the distance between the pairs of food grooves
in M. sexforis is greater than it is in I. caroliniana.

Localities.—Ravenel’s type came from The Grove, Cooper River, 17 miles from Charleston,
S.C. The large form figured in this paper came from South Carolina; but the exact locality is
not known. Other localities are Goose Creek, Cooper River, and Bostick Landing, Great
Peedee River, S. C.; Wilmington, and 3 miles north of Grifton, Pitt County, N. C.; Yorktown, Va.

Geologic horizon.—Duplin marl in South Carolina, and Yorktown formation, in North
Carolina and Virginia, both upper Miocene.

Collections—Academy of Natural Sciences of Philadelphia (1083); American Museum of
Natural History; U. S. National Museum.

39800°—15——14

206 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Genus SCUTASTER Pack.
Scutaster Pack, 1909, California Univ. Dept. Geology Bull., vol. 5, No. 18, p. 278, Pl. XXIII, fig. 2.

Description.—Vest circular depressed, ambulacral star small. Lunules in the prolongation
of the petals of the trivium, and either lacking in the bivium and posterior interambulacral
space or not placed in the same relative positions as on the anterior portion of the test (Pack).

This genus was founded on a single imperfect specimen found in the Miocene deposits of
California, which is also the type of the following species. Judging from the single figure which
Pack gives, there are good grounds for believing that the new genus should be recognized.1

SCUTASTER ANDERSONI Pack.
Plate XCIII, figure 1.

Scutaster andersoni Pack, 1909, California Univ. Dept. Geology Bull., vol. 5, No. 18, pp. 278-279, Pl. XXIII, fig. 2.
Scutaster andersont Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 704.

Description.—Only a single imperfect specimen of this species is known to exist,! and as
the writer has had no opportunity of studying it, the description of Pack is given verbatim:

Test subcircular in outline, edges markedly thin. Upper surface regularly arched from the margin; apex anterior
to the center. Apical system small and apparently central. Ambulacral star small; petals extending slightly less
than halfway to the margin of the test, closed at the ends. Lateral petals broader than the posterior ones, but of almost
the same length. Poriferous zones broad, and continuing full width almost to the ends of the petals. In the posterior
petals the interporiferous area forms about one-third the width of the petal. Poriferous zones of the lateral petals
equal in width to those of the posterior petals, but inclosed area broader. In the extension of the three anterior petals
are broad lunules, over half as long as the petals; shallow grooves extend from the lunules to the margin. Anterior
lunule slightly farther from the apical system than are the lateral ones. From the ends of the posterior petals the
plates enlarge and the area broadens rapidly. No lunules were seen here, nor in the posterior interambulacral space.
They may be represented by marginal notches, as the posterior edge of the specimen is lacking.

Dimensions.—Transverse diameter 44 millimeters; height 8 millimeters.
Locality.—Kast of Muir, Contra Costa County, Cal.

Geologic horizon.—Miocene.

Collection.—University of California.

Genus ENCOPE L. Agassiz.
ENcOPE MACROPHORA Ravenel.
Plate XCIII, figures 2a-e; Plate XCIV, figures la-f, 2.

Scutella macrophora Ravenel, 1842, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 8, pt. 2, pp. 334, 335, text figure.

Encope macrophora Ravenel, 1848, Echinide, recent and fossil, of South Carolina, p. 2.

Scutella macrophora Tuomey, 1848, Geology South Carolina Rept., p. 208:

Encope macrophora Ravenel, 1850, Am. Assoc. Ady. Sci. Proc., vol. 3, p. 160.

Encope macrophora Tuomey and Holmes, 1855, Pliocene fossils of South Carolina, pp. 2, 3, Pl. I, fig. 3.

Non Scutella hexapora Desor, 1858, Synopsis des échinides, p. 237. Desor evidently meant to give S. caroliniana
Ravenel as a synonym of S. hexapora but gave S. macrophora instead.

Encope macrophora Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Ravenellia macrophora Liitken, 1863, Bid. til Kunds. om Echinoderme; Vidensk. Medd. Kjgbenhayn.

Macrophora macrophora Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Macrophora raveneli Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., p. 74.

Ravenellia macrophora Agassiz, 1883, Mus. Comp. Zoology Mem., vol. 10, No. 1, p. 89.

Scutella macrophora Boyle, 1893, U. S. Geol. Survey Bull. 102, p. 263.

Encope macrophora Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 708.

1Since the above descriptions were written Pack has published some new information regarding this unique Californian form, based on
material recently discovered (California Univ. Dept. Geology Bull., vol. 7, No. 13, pp. 300-302, Pl. XV, figs. 2a—b, 1913). The new data establish
the genus Scutaster on a firm basis. It is characterized by hay'ng but three lunules, which are situated in the anterior ambulacral areas. The
Dew specimens show that Scutaster andersoni is transversely suboval in marginal outline, with narrow notches opposite the three anterior petals
and broad shallow notches opposite the posterior pair. The apex is anteriorly and the apical system posteriorly excentric. Longitudinal
diameter 53 millimeters; transverse diameter 62 millimeters; height 5 to 6 millimeters. The new locality is on the north slope of the San
Emigdio Mountains, at the southern end of the San Joaquin Valley, where the tests are said to occur in great abundance. In regard to geologic
horizon Pack says, ‘‘known only in the lower half of the Miocene.”’

MIOCENE ECHINODERMATA. 207

Determinative characters.—Test small to large in size, suboval to subovate in marginal
outline; truncated or convex posteriorly; shallow notches opposite the anterior petals, deep
ones opposite the posterior pair; one large lunule in the posterior interambulacrum; margin
thick; much depressed, being low and nearly flat along the front and sides, but rising toward
the center and posteriorly in a low longitudinally elongate mound. Apex slightly excentric
posteriorly, under surface flat. Ambulacral petals large, the posterior pair longer than the
rest and curved around the lunule. Apical system excentric anteriorly. Peristome small,
subcircular, excentric anteriorly; ambulacral furrows simple and straight for a short distance
from the peristome, then forking. Periproct very small, subelliptical, at the edge of the lunule
nearest the peristome.

Dimensions.—Specimen A: Length 97 millimeters; width 79 millimeters; height 18 milli-
meters. Specimen B: Length 62 millimeters; width 58 millimeters; height 11 millimeters.
Specimen C: Length 31 millimeters; width 28 millimeters; height 5 millimeters.

Description.—This handsome species, the only representative of the genus Encope yet reported
from the Cenozoic deposits of the Atlantic coast, was described by Ravenel as early as 1842. At
first he placed it in the genus Scutella, but a few years later assigned it to the genus Encope.
Both Liitken and Conrad founded new genera upon this species, but there appears to be no good
ground for the recognition of either. Conrad’s new species, Macrophora raveneli, is believed
to have been merely a young specimen of Ravenel’s species. This species is rather abundant
in a few localities in South Carolina and Florida, but is rare elsewhere. The test is variable in
size, ranging from less than an inch to nearly 4 inches in longitudinal diameter. In marginal
outline it is either suboval, somewhat ovate or obovate, or subquadrate; usually broader near
the posterior end than near the anterior end; posterior border usually truncated, sometimes
convex; a shallow notch opposite the odd petal, slightly deeper rounded ones opposite the
anterior paired petals, an large deep angular ones opposite the posterior petals; the posterior
notches vary from a flaring and subrectangular form in small specimens to a less open and more
acute form, or one with parallel sides in larger specimens. A large lunule occupies the larger
part of the posterior interambulacrum, which varies in form from circular in very small speci-
mens to oval, subovate, or subspatulate in larger ones, the elongation being longitudinal when
occurring; the width of the lunule is usually greater near the under surface, especially in large
specimens. The whole form, including the margin, is thick, particularly so in large individuals.
The whole test is much depressed, being nearly flat along the front and sides; but rising toward
the center in a low longitudinally elongate mound which extends from about the middle of the
odd petal to the posterior border. The height of the mound varies directly with the size of the
specimen, ranging from less than an eighth to more than three-fourths of an inch. The apex
is central or subcentral, being usually slightly excentric anteriorly, though sometimes slightly
excentric posteriorly at the summit of the central mound, which is usually the anterior end
of the raised and thickened margin of the lunule. The depressed marginal area is more or
less distinctly corrugated by alternating low ridges and shallow troughs, there being two or
three troughs between the notehes in the margin. The under surface is flat or slightly concave,
usually increasingly concave near the margin of the lunule. :

The ambulacral areas are narrow in the petaloid region, wide in the marginal region where
they about equal the interambulacral areas. The dorsal portions are petaloid. The petals are
large, unequal in length, divisible intoa bivium and a trivium; those of the trivium usually sub-
equal in length, sometimes with the odd petal shorter than the other two, subelliptical or some-
what spatulate in form; those of the bivium much longer than the others, tapering gradually
from the distal ends toward the apical system, gracefully curved around the lunule, all the petals
open at the ends and extending about two-thirds the way to the margin. The poriferous zones
are wide, as wide as or slightly wider than the interporiferous areas; the inner rows of pores nearly
parallel and composed of rather large oval pores, outer row of smaller oval or elliptical pores at
the bottom of deepened portions of very narrow grooves by which the pairs of pores are
conjugated.

908 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The interambulacral areas, except the posterior area, are narrow in the petaloid region,
wider in the marginal region; the posterior interambulacral area is wider and its plates differ
considerably in form from those of the other areas, because of the presence of the lunule. The
whole surface of the test is covered with small uniform tubercles which are larger on the under-
surface and inside the lunule.

The apical system is excentrie anteriorly, in front of and below the apex on the more or less
steeply sloping anterior side of the central mound. The madreporite is large, stellate or sub-
pentagonal, nearly flush with the surface. There are five genital pores a short distance away
from the points of the madreporic star, their relative positions varying somewhat, and five
small radial plates each perforated by a small pore, on the proximal side of which there is a very
small swelling. The posterior genital pore is sometimes somewhat displaced from the median
line.

The peristome is small, subcircular to subpentagonal, excentric anteriorly; the ambulacral
furrows rather deep, simple and straight for a short distance from the peristome, then forking,
each pair of branches diverging somewhat, the three anterior pairs more so than the posterior
two, extending to the margin and ending close alongside of the marginal notches. Each branch
gives off one side branch on the outside at nearly right angles about haltway from the peristome
to the margin, which soon bend and proceed to the margin. A very thin ridge extends out from
the peristome along the middle of the short unbranched portion of each ambulacral furrow.

The periproct is very small, much smaller than the peristome, usually elliptical or sub-
elliptical, sometimes subcircular or subpyriform, situated usually on the sloping edge of the lunule
nearest the peristome, sometimes on the inner wall of the lunule, but near the under surface of
the test.

This species presents variable features which illustrate in an interesting way changes due to
the development of the individual. As the forms increase in size and age the lunule enlarges and
becomes more elongate and irregular, the posterior marginal notches become less flaring and tend
to close, the posterior edge changes from a truncated one to one more and more convexly rounded,
the posterior end becomes at first relatively broader then relatively narrower than the anterior
end, the height of the central mound and thickness of the margin increase, the corrugations on
the upper surface become more accentuated, and irregularities appear in the poriferous zones.
Lack of space forbids a more complete discussion of these features here; but a comparison of the
figures given will bring them out in a stronger light. Specimen A, for instance, presents geruntic
features, the effect of the elongation of the lunule in pushing out and rounding the posterior
border, nearly closing the posterior notches and so changing the marginal outline as to make the
form seem at least varietal in value if not a different species.

Related forms.—The only American fossil echinoid resembling this species is E. tenuis Kew,?
from the upper Miocene or lower Pliocene of the Pacific coast. H. macrophora is easily separated
by its larger lunule, shallower anterior notches, posterior petals curving around the lunule, and
having the periproct at the edge of the lunule. The recent species Encope grandis L. Agassiz,
reported by A. Agassiz? from the Gulf of California, is the most closely related to the present
form, the very features which A. Agassiz notes as remarkable in EL. grandis bemg those most
characteristic of EL. macrophora. . grandis differs, however, in having all five marginal notches,
and especially the three anterior ones, larger and more deeply incised, in having wider interpo-
riferous areas, and the posterior margin concave. Hnecope emarginata Agassiz, a recent species
from the coast of Brazil and the West Indies, is similar in general outline to EH. macrophora, the
young forms of the two species being quite similar, although the lunule of the young /. maero-
phora is usually more circular than that of the young H. emarginata. The older forms of £.
emarginata also differ in that the marginal notches become lunules, a change which appears
never to take place in L. macrophora. Possibly the present fossil form may be ancestral to £.
emarginata. Encope ciz De Cartazar, from the upper Miocene of Cuba, presents some points
of similarity to the present species, but its lunule is smaller and more rectangular in form, its

1 Revision of the Echini, p. 545 and Pl. XIII, fig. d.

2 The description of Z. tenuis Kew appeared while the present work was in press. See California Univ. Dept. Geology Bull., vol. 8, No.5,
pp. 47-48, Pl. I, fig. 1, and Pl. II, fig. 1, 1914.

MIOCENE ECHINODERMATA. 209

posterior marginal notches are less pronounced and have one side merging into its more rounded
posterior margin.

Localities —Dr. Ravenel’s plantation, known as ‘The Grove,’ on Cooper River, 17 miles
from Charleston, and Goose Creek, S. C.; Alligator Creek, Monroe County, and near Punta Garda,
Alligator Creek, Monroe County, Fla.

Geologic horizon.—Duplin marl, upper Miocene, in South Carolina, Caloosahatchee marl,
Pliocene, in Florida.

Collections. Academy of Natural Sciences of Philadelphia (1086, A); U.S. National Museum
(164658, B; 9970, C); American Museum of Natural History; Boston Society of Natural History;
Wagener Free Institute of Science.

Family CLYPEASTRID®.

Genus CLYPEASTER Lamarck.
CLYPEASTER BOWERSI Weaver.
Plate XCOVI, figures la-b.

Clypeaster bowerst Weaver, 1908, California Univ. Dept. Geology Bull., vol. 5, No. 17, pp. 271-272, Pl. XXI, fig. 1;
Pl. XXII, fig. 1.
Clypeaster bowersi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 701.

Description.—As the writer has had no opportunity of studying the single specimen! of
this large Clypeaster that has been discovered the description of Weaver is here given verbatim:

The test of this form is very large and thick. The largest specimens measured 119 millimeters in diameter. The
outline seen from above is circular to elliptical. The margins are swollen and the summit very slightly elevated.
On the posterior margin is a faint reentrant angle opposite the anal opening. The petals are broad and nearly closed
at the extremity. The median interporiferous zones are broad, while the outer rows of pores converge at the ends
so as almost to inclose them. The tuberculation is uniform on both the upper and lower surfaces and the tubercles
are of nearly the same size over the whole test. The actinal surface is strongly concave and the actinostome deeply
sunken. The ambulacral furrows are very deep and extend from the actinostome to the margin.

' Dimensions.—Maximum width 100 millimeters; maximum length 119 millimeters; maxi-
mum thickness 37 millimeters.
Related forms.—Weaver makes the following remarks on related forms:

Clypeaster bowersi differs considerably from the other members of this genus on the Pacific coast. It is not far
removed from C. breunigei Laube, which occurs in the Eocene in the Lybian Desert of Africa. C. bowersi is nearly
twice as large as C. brewnigei and is ellipsoidal in outline with thick margins, while the latter is pentagonal and has
thin margins. The upper surface of the former is only slightly arched, while the apical system of the latter is conical
and then gradually slopes to the margin. They differ also in the character of the petals and in the position of the
anal pore. In C. bowersi the petals are broad and the poriferous zones lie nearly parallel. The anus is situated on
the actinal surface at a distance from the margin about equal to its diameter.

Clypeaster bowersishows a close relationship to Diplothecanthus rosaceus (Lamarck). It differsin that it ismuch
flatter, the superior surface of D. rosaceus being more strongly convex. The actinostome of the former is sunken ina
cavity which narrows gradually and is of much greater extent than in D. rosaceus. In D. rosaceus the ambulacral
areas are more or less swollen and rise above the general level of the test, while in C. bowersi they are nearly at the
same level as the interambulacral areas. The posterior ambulacral petals are the longest and the odd ambulacral
petal is the shortest in D. rosaceus. In C. bowersi the odd. ambulacral petal is the longest and the remaining four are of
equal size.

Locality.—Colorado Desert (Weaver).*

Geologic horizon.—Associated with a fauna presumed to be of Miocene age (Weaver).!
Collection.—University of California.

1Since the above description was written William S. W. Kew has published some additional data relative to C. bowersi based on new
material collected by him (California Univ. Dept. Geology Bull., vol. 8, No. 5, p. 50, Pls. IV, V, 1914). He supplements Weaver’s description
by mentioning that there are faint reentrant angles opposite all the interambulacral areas, that the petals are obovate, that the anterior petal is
somewhat raised, and that the periproct is large, depressed, and inframarginal. Kew gives several new localities, all being near Coyote Moun-
tain, Carrizo Creek region, California. He also says that C. bowersi occurs at all the localities, in his lower division of the Carrizo Creek forma-
tion, the age of which has not yet been definitely determined. Arnold, in 1910 (Willis and Salisbury, Outlines of geologic history, p. 245),
regarded the Carrizo Creek beds as equivalent to the Etchegoin formation which is now thought to be upper Miocene and lower Pliocene (?).

210 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

CLYPEASTER? BREWERIANUS (Rémond).
Plate XCVI, figures 2a—c, 3.
Echinarachnius brewerianus Rémond, 1863, California Acad. Sci. Proc., vol. 3, p. 53; no figure.
Echinarachnius brewerianus Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.
Echinarachnius brewerianus Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, pp. 36, 109, PI. XII, fig. 65, 65a.
Echinarachnius brewerianus Cooper, 1888, Cat. California fossils: State Mineralogist Seventh Rept., p. 271.
Clypeaster (2?) brewerianus Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 166, Pl. XX1,

fig. 2.

Asiwadioasts brewerianus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 702.

Determinative characters—Test small, subelliptical to subcireular m marginal outline,
faintly notched opposite posterior petals, longer than broad. The whole form is much depressed ;
upper surface somewhat convex, flattened near center, margin rather thick, rounded; apex
central; under surface flat near margin, slightly concave near center. Ambulacral petals sub-
equal, plates long and narrow, poriferous zones diverging from apical region to near margin,
with a slight constriction about two-thirds the way. Apical system central. Peristome
probably central. Periproct very small, subcircular, inframarginal, almost marginal. _
Dimensions.—Specimen A: Length 32 millimeters; width 28 millimeters; height 9 milli-
meters. Specimen B; length 36 millimeters; width 31 millimeters; height 12 millimeters.

Description —This species was described but not figured by Rémond as early as 1863, was
first figured by Gabb in 1869; and was redescribed and refigured by Merriam in 1899. The
test is small, rarely exceeding 14 inches in length. In marginal outline it is subelliptical to
subcircular, faintly notched opposite posterior petals, longer than broad. The whole form is
considerably depressed; the upper surface risimg in gentle convex curves from the moderately
thick, rounded margin to a flattened area near the centrally located apex; the under surface
flat near the margin, slightly concave toward the center.

The ambulacral areas are wide, wider throughout than the interambulacral areas, the
plates being long and narrow in the petaloid region and just at the margin; the dorsal portions
petaloid. The petals are subequal in length, sharply pointed near the apical system, widening
rapidly for two-thirds their length, then narrowing slightly and again widening rapidly to their
ends where they are wide open. Several pairs of pores continue beyond the petals proper,
diverging from the ends of the petals to the margin. The interporiferous areas are very wide,
from three to four times as wide as the poriferous zones, flush or slightly tumid; poriferous
zones very narrow near apical system, rather wide near ends of petals; pores oval, pairs
conjugated.

The interambulacral areas are relatively narrow, very narrow near the apical system.
The test is covered with small,. nearly uniform tubercles, which are of nearly the same size on
the upper and lower surfaces.

Tne apical system is central and coincident with the apex. The details can rarely be
made out on the specimens.

The peristome and ambulacral grooves could not be clearly made out on the specimens
studied. One fragment examined indicated that the peristome is small, central, or subcentral
and circular.

The periproct is very small, subcircular, and inframarginal, almost marginal.

Related forms.—This species does not appear to be closely related to any other American
species. It resembles Astrodapsis tumidus somewhat, as noted by Merriam, but lacks the
alternating tumid petals and depressed interambulacral areas characteristic of that species.
Until specimens showing the ambulacral grooves are found the generic position can not be
determined with certainty.

Localities.—_Near Lafayette, Concord quadrangle; 2 miles east of Walnut Creek House,
Walnut Creek, Cal.

Geologic horizon.—‘ Upper Contra Costa Miocene,” probably San Pablo formation, upper
Miocene.

Collections.— University of California (19423, B); Academy of Natural Sciences of Philadel-
phia (1088, A).

MIOCENE ECHINODERMATA. 211

CLYPEASTER? GABBI Rémond.

Clypeaster gabbi Rémond, 1863, California Acad. Sci. Proc., vol. 3, pp. 53, 54, no figure

Clypeaster gabbi Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Clypeaster gabbi Gabb, 1869, Geol. Survey California, Paleontology, vol. 2, pp. 36, 109, Pl. XIT, figs. 64, 64a.

Clypeaster gabbi Cooper, 1888, Catalogue of California fossils: State Mineralogist Seventh Rept., p. 271.

(?) Seutella gabbi Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 168, Pl. XXII,
figs. 5, 5a.

Description.—As the writer has been unable to examine any specimens which can be posi-
tively referred to this species, Rémond’s description is given verbatim:

Disk rather small, comparatively thick, varying from circular to subpentagonal and irregular suboyal. Apex
nearly central, subelevated; margin rounded; genital apparatus subangular. Ambulacral star almost symmetrical;
petals about equalin length, elongated, open at their extremities. Inferior surface flat near the edge and gently
concave in the center. Mouth depressed, subcentral. Ambulacral furrows straight, slightly marked. Anal aper-
ture very small, marginal. Tubercles of the upper surface numerous, especially in the ambulacra, round and
prominent.

Dimensions.—According to Rémond the “ greatest diameter is 1.16 inches, smallest diame-
ter 1.10 inches, height 0.28 inch.”

Related forms.—As Rémond unfortunately failed to figure his form, and as no specimens
answering satisfactorily to his description are available, considerable uncertainty exists regard-
ing this species and its relations to other Californian echinoids. As stated in the discussion of
Scutella gabbi (Rémond) Merriam (p. 189), the form described and figured by Merriam differs
in several important particulars which can not be ignored, and this renders it doubtful whether
Merriam has described and figured identically the same form as Rémond. Additional collect-
ing at Rémond’s locality may result in discovering specimens answering to his description,
otherwise the species must remain of doubtful character.

Locality and geologic horizon.—According to Rémond, this species ‘ occurs abundantly
on the eastern shore of San Pablo Bay, south of Mare Island, Cal., in soft sandstones of
Miocene age.”

Order ATELOSTOMATA.

Suborder ASTERNATA.
Family CASSIDULID&.

Genus CASSIDULUS Lamarck.
CASSIDULUS BASSLERI Twitchell, n. sp.
Plate XCV, figures 5a-d.

Determinative characters —Test small, subovate to subcircular in marginal outline, broadest
posteriorly; upper surface convex, somewhat flattened on top, sides equally declining; margin
rounded on the sides and anteriorly, somewhat angular at the rostrated posterior end; under-
surface concave centrally. Apex central; apical system excentric anteriorly. Ambulacral
areas rather broad in petaloidal dorsal portions, narrower elsewhere; poriferous zones broad,
outer row of pores slitlike or elongate elliptical. Peristome small, central, pentagonal to sub-
stellate, with large well-defined floscelle. Periproct oval, situated rather high above the margin,
in a short sulcus.

Dimensions —Length 28 millimeters; width 25 millimeters; height 14 millimeters.

Description —Specimens of this species have been known for some years; but it has usually
been confused with the Cretaceous species Cassidulus squoreus Morton and so labeled in the
collections. It is named in honor of Ray S. Bassler, of the U.S. National Museum. The test
is small, rarely exceeding an’inch in diameter; subovate to subcircular in marginal outline,
usually slightly broader posteriorly than anteriorly and slightly longer than broad. The upper
surface is moderately elevated, the height being equal to about half the diameter, convex, some-
what flattened on top from above the periproct to the apical system, equally declining anteriorly
and on the sides, posteriorly it slopes from above the periproct to the margin in a steep, oblique,

212 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

nearly straight lime; margin rounded along the sides, less so at the anterior end, somewhat
angular at the rostrated posterior end; undersurface flattened, concave centrally. The apex is
central or subcentral.

The ambulacral areas are rather broad in the petaloid dorsal portions, less so at the ambitus,
and narrow at the ends of the petals and actinally; the petals are relatively large, broad, sub-
equal in length, extending two-thirds or more of the distance to the ambitus; the poriferous
zones are broad, though less so than the interporiferous areas, outer row of pores slitlike or
elongate elliptical, inner row round, pairs of pores conjugate.

The surface of the test is closely set with small imperforate tubercles set in deep scrobi-
cules. The tubercles increase in size on the undersurface except along a median band which
is somewhat smooth but dotted with numerous granulations.

The apical system is excentric anteriorly. There are four genital pores, the anterior pair
being nearer together than the posterior. The right anterior genital plate, which is modified
to form the madreporite, is very large, occupying the larger part of the system. ‘There are
five small radial plates, each perforated by a small pore.

The peristome is small, central, pentagonal to substellate, with a large floscelle with promi-
nent bourrelets and well-defined, broad, oval phyllodes.

The periproct is oval, or subelliptical, longitudinally elongate, in a short sulcus situated
rather high above the posterior margin. The ends of the posterior petals are about opposite the
middle of the periproct.

Related forms.—This species is similar in a number of features to Cassidulus berry, but it
is more elevated, has a more rounded margin and has its peristome central instead of anteriorly
excentric. It also presents interesting resemblances to the Cretaceous species C. xquoreus,
and (C. micrococcus, but can be separated from the former by its more subcircular marginal out-
line, its central peristome, the slightly higher position of its periproct, and the more elongate
character of the outer row of pores of its petals, and from the latter by its much smaller size,
its relatively larger floscelle, and the somewhat lower position of its periproct.

Locality and geologic horizon.—The specimens on which this species is founded are said to be
from the Miocene of North Carolina. They can not be more definitely located.

Collection.—U.S. National Museum (9476).

GALERITES OREGONENSIS Dana.

Galerites oregonensis Dana, 1849, Repv. U. S. Expl. Exped., Geology, vol. 10, p. 729, Pl. II, figs. 5, 6, 6a.
Galerites oregonensis Gabb, 1869, Geol. Survey of California, Paleontology, vol. 2, p. 123.

This species was based by J. D. Dana on a few fragments and spines obtained from the
argillaceous Astoria shale of the lower Miocene of Oregon. The spines are said to be “‘half an
inch long, very slender, delicately striate, with the striz punctate or suberenulate.”” No descrip-
tion of the test is given and Dana himself said the ‘‘specimens are so imperfect that we refer it
with hesitation to the genus Galerites.’’ In view of the imperfect character of the specimens,
the acceptance of the species is reserved until additional material has been obtained.

Suborder STERNATA.

Family SPATANGID.
Genus AGASSIZIA Valentin.
AGASSIZIA PORIFERA (Ravenel).
Plate XCVII, figures la-d.

Brissopsis poriferus Ravenel, 1848, Echinide, recent and fossil, South Carolina, p. 4, Pl. II, figs. 5, 6.
Brissopsis poriferus Ravenel, 1850, Am. Assoc. Ady. Sci. Proc., vol. 3, p. 160.

Agassizia porifera McCrady, 1857, Pliocene fossils, South Carolina, pp. 5, 6, Pl. I, fig. 5, Pl. Il, fig. 4. -
Agassiza porifera Meek, 1864, Check list, Miocene, p. 2.

(?) Agassizia excentrica A. Agassiz, 1872, Revision of the Echini, pt. 1, p. 88.

Agassizia porifera A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751.

Agassizia porifera Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

MIOCENE ECHINODERMATA, 213

Determinative characters.—Test moderate, ovoid, tall, apex slightly excentric forward, no
anterior groove, nearly flat below. Ambulacra narrow, paired in shallow grooves, antero-
lateral much longer than the posterolateral; pairs small, slitlike. Interambulacra broad,
covered with very small tubercles. Fascioles indistinct. Peristome near forward margin.

Dimensions.—Length 42 millimeters; width 37 millimeters; height 35 millimeters.

Description.—This species was figured by Ravenel in 1848, and described and figured by
McCrady in 1858. The test is of moderate size, ovoid, and tall. The apex is slightly excentric
forward. There is no anterior groove, a slight depression extending from the apex part way
to the margin. The lower surface is nearly flat.

The ambulacra are narrow, the posterolateral pair bent outward toward the margin. The
anterolateral nearly straight. The paired ambulaera in shallow depressions, long, open below,
the posterolateral shorter than the anterolateral pair.

The interambulacra are wide, the paired interambulacra slightly gibbous at their upper
ends. Portions of the peripetalous and lateral fascioles are rather indistinctly shown.

The peristome is near the anterior margin with a well-developed labrum. The periproct
is not shown on the single specimen of this species studied.

Locality.—Near Oakley Inlet, Waccamaw, S. C.

Geologic horizon.—Miocene.

Collection.—American Museum of Natural History.

Genus ECHINOCARDIUM Gray.

ECHINOCARDIUM ORTHONOTUM Conrad.

Plate XOVII, figs. 2a-c; Plate XCVIII, figs. la-c, 2a-c.
Spatangus orthonotus Conrad, 1843, Acad. Nat. Sci. Philadelphia Proc., vol. 1, p. 327.
Amphidetus virginianus Forbes, 1845, Geol. Soc. London Quart. Jour., vol. 1, pp. 425, 426, 3 figs.
Amphidetus virginianus Forbes, 1846, Geol. Soc. London Proc., vol. 6, pp. 559, 560, 3 figs.
Amphidetus orthonotus Tuomey and Holmes, 1855, Pliocene fossils, South Carolina, pp. 6, 7, figs. 1, la-c.
Amphidetus virginianus Emmons, 1858, North Carolina Geol. Survey Rept., p. 310, fig. 245a-c.
Echinocardium virginianum Desor, 1858, Synopsis échinides fossiles, p. 408.
Echinocardium orthonotus Conrad, 1865, Acad. Nat. Sci. Philadelphia Proc., vol. 17, p. 75.
(2?) Echinocardium pennatifidum A. Agassiz, 1872, Revision of the Echini, pt. 1, p. 111.
Echinocardium orthonotum A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751.
Amphidetus virginianus Schluter, 1899, Deutsche Geol. Gesell. Zeitschr., vol. 51, p. 118.
Echinocardium orthonotum Clark, 1904, Maryland Geol. Survey, Miocene, pp. 430-432, Pl. CXIX, figs. lac.
Echinocardium orthonotum Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706.

Determanative characters.—Test large, ovate to cordiform, elevated, upper surface nearly
flat forward, deep and broad, anterior groove higher posteriorly with truncated surface, tumid
plastron below. Ambulacra wide, anterior in broad groove, paired ambulacra in shallow
grooves triangular in outline, widely open above, narrow below; pore pairs large and not numer-
ous. Interambulacra narrow above, wide below; fascioles distinct. Peristome large, slitlike.
Periproct high on posterior truncation. ;

Dimensions.—Specimen A: Length 58 millimeters; width 52 millimeters; height 29 milli-
meters. Specimen B: Length 51 millimeters; width 46 millimeters; height 29 millimeters.

Deseription.—This species was first described by Conrad in 1848, but not figured. Forbes,
in 1845, redescribed and figured the form under the name of Amphidetus virginianus. The
test is rather large, irregularly ovate to cordiform, elevated but more posteriorly than anteriorly.
The upper surface is mostly flat forward. A broad and rather deep anterior groove with slightly
gibbous edges indents the upper surface but narrows and shallows toward the margin. The
posterior portion is elevated into a broad ridge which continues nearly to the truncated posterior
margin. The lower surface is nearly flat except for the elevated plastron.

The ambulacra are wide, the anterior being situated in the broad anterior groove. The
paired ambulacra are situated in shallow grooves on the upper surface. They are triangular
in outline, widely open above and narrow below, the anterolateral being wider above than the

914 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

posterolateral. The pore pairs are large and not numerous. They appear again on the lower
surface near the peristome.

The interambulacra are narrow above and widen rapidly. They have numerous large
tubercles below which become few and irregularly scattered above the lower margin. The
fasciole can be plainly traced.

The apical system is small. The peristome is large and slitlike, very much elongated
transversely. The periproct is moderate in size, high on the posterior truncation.

Locality —James River, Va.

Geologic horizon.—Y orktown formation, upper Miocene.

Collections.—Academy of Natural Sciences of Philadelphia (1079); American Museum of
Natural History; U.S. National Museum; Johns Hopkins University (T. 1002).

ECHINOCARDIUM DEPRESSUM Clark, n. sp.
Plate XCVIII, figures 3a-c.

Determinative characters.—Test moderate, cordiform, low, depressed, both upper and
lower surfaces nearly flat, anterior groove shallow, posterior truncation. Ambulacra wide,
anterior in shallow groove, paired in grooves, triangular in outline, open above, narrow below.
Interambulacra narrow above, widening rapidly toward the ambitus. Peristome small.

Dimensions.—l ength 40 millimeters; width 37 millimeters; height 13 millimeters.

Description.—This species is represented only by casts, which, however, are very different
in their characters from Z. orthonotum, the only other Miocene representative of this genus from
American deposits. The test is of moderate size, cordiform, low, much depressed, nearly flat.
The anterior groove is shallow and broad. The posterior margin is truncated.

The ambulacra are wide, the paired ambulacra being situated in shallow grooves triangular
in outline. They are open above and narrow below. The interambulacra are narrow above,
forming a very obtuse angle, but widening rapidly below toward the ambitus. The fascioles
are absent. The peristome is small and apparently transversely elongated.

Locality.—Near old Chattahoochee Landing, Apalachicola River, Fla.

Geologic horizon.—Lower Miocene.

Oollection.—U. S. National Museum (164454).

EcHINOCARDIUM GoTHICUS (Ravenel).

Amphidetus gothicus Ravenel, 1848, Echinidz, recent and fossil, South Carolina, p. 4 and figure.
Amphidetus ampliphorus McCrady, 1855, Pliocene fossils, South Carolina, pp. 7, 8, Pl. II, fig. 2.
Amphidetus gothicus McCrady, 1855, Pliocene fossils, South Carolina, pp. 7, 8, Pl. II, fig. 3.

(2) Echinocardium cordatum A. Agassiz, 1872, Revision of the Echini, pt. 1, pp. 109, 110.
Amphidetus gothicus A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751.

Echinocardium ampliflorus, Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.
Echinocardium gothicum Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description.—No material has been secured and it is therefore impossible to satisfactorily
describe this species. A. Agassiz regards E. gothicus and E. ampliphorus as the same species
and refers it doubtfully to EZ. cordatum, which is found widely distributed in the Atlantic Ocean
to-day.

Locality.—The Grove, Cooper River, S. C.

Geologic horizon.—Duplin marl, upper Miocene.

Collection —Unknown.

Genus LINTHIA Merian.

LintuiA? CALIFORNICA Weaver.

Plate XCVIII, figure 4.

Linthia (?) californica Weaver, 1908, Univ. California Dept. Geology Bull., vol. 5, No. 17, pp. 272, 274, Pl. XXI, fig. 2.
Brissopsis californica Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.

MIOCENE ECHINODERMATA. 215

Description.—Weaver says:

The outline of the test from above is elliptical. The anterior groove is deep. The apical system is small and
situated slightly anterior to the center. The central portion of the lateral interambulacral plates forms a series of
irregular ridges extending from the apical system to the margin. The posterior interambulacral area is elevated. The
three anterior ambulacra are nearly equal in size and larger than the posterior areas as far as known. The poriferous
zones of the ambulacra are narrow, but the pores are large. The specimen is a poorly preserved cast and further data
are lacking. This species has been referred to Linthia rather than to Schizaster on account of the more central position
of the apical system.

Dimensions.—Length 19 millimeters; width 14 millimeters; height 7 millimeters.
Locality.—One mile west of Bear Valley, Contra Costa County, Cal.

Geologic horizon.—Lowest member of the Monterey shale, middle Miocene.
Collection.—University of California.

Genus BRISSUS Leske.
Brisstus sparrosus (Ravenel).

Pericosmus spatiosus Ravenel, 1848, Echinid, recent and fossil, South Carolina, P 4,
Hemiaster (Pericosmos) spatiosus Ravenel, 1850, Am. Assoc. Ady. Sci. Proc., vol. 3, p. 160.
Brissus spatiosus McCrady, 1855, Pliocene fossils, South Carolina, p. 8, Pl. ITT, fae 1, la-e.
Brissus spatiosus Meek, 1864, Check list, Miocene, p. 2.

Meoma ventricosa A. Agassiz, 1872, Revision of the Echini, pt. 1, p. 143.

Meoma spatiosa Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description.—This species, which was named by Ravenel, was subsequently figured and
described by McCrady. It is regarded by A. Agassiz as a synonym of Meoma ventricosa. No
specimens have been found for the present study, and in the absence of material it is difficult to
determine the true relations of the species, although it may well belong to the genus Meoma.

Locality. —The Grove, Cooper River, S.C.

Geologic horizon.—Duplin marl, upper Miocene.

Collection.—Unknown.

_ Genus METALIA Gray.

METALIA RAVENELIANA (McCrady).

Plagionotus ravenelianus McCrady, 1855, Pliocene fossils, South Carolina, pp. 10, 11, Pl. ITI, figs. 3, 3a.
Plagionotis ravenelianus Meek, 1864, Check list, Miocene, p. 2.

Plagionotus ravenelianus A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751.

Plugiobrissus ravenelianus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description.—No material has been secured and it is therefore impossible to satisfactorily
describe this species. The genus Plagionotus is now regarded as a synonym of Metalia.
Locality.—The Grove, Cooper River, S. C.
Geologic horizon.—Duplin marl, upper Miocene.
Collectton.—Unknown.
Meratra HoLMEst (McCrady).

Plagionotus holmesii McCrady, 1855, Pliocene fossils, South Carolina, pp. 9, 10, Pl. IIT, figs. 2, 2a.
Plagionotus holmesii Meek, 1864, Check list, Miocene, p. 2.
Plagionotus holmesii A. Agassiz, 1874, Revision of the Echini, pt. 4, p. 751.
Plagiobrissus holmesi Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.
Description.—No material has been secured and it is therefore impossible to satisfactorily
describe this species. The genus Plagionotus is now regarded as a synonym of Metalia.
Locality.—Goose Creek, S. C.
Geologic horizon.—Duplin marl, upper Miocene.
Collection.—Unknown.

PLIOCENE ECHINODERMATA.
Class ECHINOIDEA.

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder ECHININA.

Family STRONGYLOCENTROTID&.

Genus STRONGYLOCENTROTUS Brandt.
STRONGYLOCENTROTUS DROBACHIENSIS (Miiller).

Plate XCIX, figures la-c.

Description.—Two specimens have been examined from the Pliocene beds of Caloosahatchie
River that evidently belong to this common and widespread Recent species. The characters are
similar to those of living forms, and it seems therefore that the specimens must be regarded as
representing the same species. A. Agassiz? points out the great variability in the different
individuals of the species, forms much more extreme than those of the two Pliocene specimens
studied occurring. , /

Dimensions.—Diameter 55 millimeters; height 27 millimeters.

Locality.—Caloosahatchie River, Fla.

Geologic horizon.—Pliocene.

Collection.—Wagner Free Institute of Science (4350).

Subclass IRREGULARIA.
Order GNATHOSTOMATA.
Suborder CLYPEASTRINA.

Family SCUTELLID. :

Genus DENDRASTER Agassiz.

DENDRASTER INTERLINEATUS (Stimpson).
Plate C, figures 2a-b.

Scutella interlineata Stimpson, 1856, Pacific Railroad Repts., vol. 5, pp. 153, 154. Pl. IV, fig. 30.

Scutella interlineata Rémond, 1863, California Acad. Nat. Sci. Proc., vol. 3, pp. 14, 15.

Scutella interlineata (Blake) Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Scutella interlineata Gabb, 1869, Geol. Survey California Rept., Paleontology, vol. 2, p. 110.

Scutella interlineata Cooper, 1888, Cat. California fossils: State Mineralogist Seventh Rept., p. 271.

Scutella interlineata Merriam, 1899, California Acad. Nat. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 169, Pl. XXII,
fig. 6.

Dendraster (?) interlineatus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706.

Description and determinative characters.—The writer has been unable to secure for study
more than a few specimens of this species. Among these is Stimpson’s type—a greatly weath-
ered and fragmentary specimen. As Merriam, on the other hand, has had considerable material
to work with, his description is here repeated:

Test pentagonal to circular, angular or truncated posteriorly, somewhat arched above; summit nearly central and
in front of the excentric apical system, specimens ranging up to over 120 millimeters in diameter.

1 Revision of the Echini, pp. 277-281.

216

PLIOCENE ECHINODERMATA. 217

Ambulacra rather broad, of unequal length, anterior three of about the same length and longer than the posterior
pair. Anterior petal open at the end, the others nearly closed. Few if any pores continuing beyond the ends of the
petals.

The distance from the excentric apical system to the posterior margin is to the distance to the anterior margin as
1to 1.5. The anus is supramarginal, being separated from the margin in adult specimens by about the width of one
of the marginal interambulacral plates.

No specimens have been seen by the writer in which the ambulacral furrows are well shown. On such specimens
as show the lower side, the furrows seem to be dichotomously divided near the mouth. This agrees with Rémond’s
description, which also states that the furrows are not as well marked nor as much branched as in Dendraster excentricus.

The spines of the upper surface are about 1 millimeter long; they are longitudinally striated and at the distal
end are strongly swollen and obliquely truncated or bent. The spines of the lower surface are slender striated rods
about 2 to 3 millimeters long. The tubercles differ little in size on the upper and lower surfaces.

The internal skeleton comprises numerous irregular pillars and plates near the margin and a pair of radial plates in
each interambulacral space.

Dimensions.—The specimens vary from small to large, ranging, according to Merriam, up
to 120 millimeters in diameter. The specimen figured gave: Length 56 millimeters; width 56
millimeters; height 5 millimeters.

Related forms.—D. interlineatus is very closely related to D. oregonensis. There appear to
be differences, however, which justify the separation of the two forms, to judge from the speci-
mens studied. D. oregonensis is to be distinguished by the details of its ambulacral petals. In
both the anterior and posterior paired petals the posterior poriferous zones are straight, while in
D. interlineatus all are curving, or at most only the posterior zones of the posterior pair become
nearly straight. In D. oregonensis all of the petals are well open at the ends, the poriferous zones
converging slightly or not at all toward the ends and diverging sharply at the ends, with severa]
pairs of pores occurring between the ends of the petals and the margin; while one of the most
striking characters of D.interlineatus is the curving around abruptly toward each other of the
poriferous zones so as to practically close the petals in all but the anterior petal. D. oregonensis
differs further in having less symmetrically subelliptical petals, in being relatively higher in
proportion to its width, and in having a relatively larger periproct.

D. interlineatus also resembles S. fairbanksi and S.gabbi; but both of these forms can be
easily distinguished by the central or slightly anteriorly excentric position of their apical systems,
their relatively smaller and more equal petals, and their wider marginal areas.

Locality.—™m the sea cliffs about one-fourth mile above Mussel Rock (figured specimen) ;
south of Point Lobos, near San Francisco (type); Ano Nuevo Creek, near Felt Lake and in the
sea cliffs between Santa Cruz and Capitola, and at Rio Dell Diller, Cal. (Arnold).

Geologic horizon—Merced formation, upper Phocene.

Collections —U. 8S. National Museum; University of California (19427).

Genus ASTRODAPSIS Conrad.
ASTRODAPSIS FERNANDOENSIS Pack.
Plate CI, figures 1, 2.

Astrodapsis fernandoensis Pack, 1909, California Univ. Dept. Geology Bull., vol. 5, No. 18, p. 279, Pl. XXIV, figs. 3, 4.
Astrodapsis fernandoensis Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706.

Description.—As the writer has had no opportunity to study any specimens of this species,
the description of Pack will be given in full.

Test small; suboval in outline, anterior end rounded, posterior end slightly pointed; much depressed, upper
surface very slightly convex, apex central; edges rounded. Apical system central; petals extend to margin, wide
open at the end, raised near the apical system but almost flush with the surface of the test near the margin. Poriferous
zones very narrow, together forming about one-fourth the width of the petal. The two posterior petals are gently
convex toward the median line through the posterior interambulacral space. A broad, shallow depression occupies
the center of the interambulacral areas; the two secondary depressions so prominent in Astrodapsis antiselli are almost
entirely lacking. Actinal surface gently concave, furrows poorly marked, but apparently branched as in Astrodapsis
antiselli. Anal pore submarginal, large, and ovalin outline. The posterior end of the test is produced beyond the pore
to a small point, particularly noticeable in the smaller specimens. Tubercles very large, and set in well-defined pits
apparently the same on upper and lower surfaces.

\

218 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Dimensions.—Length 51 millimeters; width 39 millimeters; height 8 millimeters.

Related forms.—Judging from Pack’s figures and description A. fernandoensis is very closely
allied to A. antiselli Conrad, the most notable points of resemblance being the oval outline, the
slight pointing of the posterior end, the rounded edges and the slight convexity of the upper
surface. The points of resemblance are so striking as to raise the question, whether A. fernando-
ensis ought not to be regarded as a synonym of A. antiselli; but as Pack does not state that the
margin of A. fornomdlommes | is very thick and as the figures suggest a greater contrast between
the Glevation of its ambulacral ridges and the dawn of its iaenambaleer al depressions than
occurs in A. antiselli, decision is reserved until authentic specimens of Pack’s form can be
examined.

Locality.—Elsemere Canyon, Los Angeles County, Cal.

Geologic horizon.—Fernando formation, lower Pliocene beds.

Collection.—University of California ae B).

Family CLYPEASTRID®.
Genus DIPLOTHECANTHUS Duncan.
DIPLOTHECANTHUS DALLI Twitchell, n. sp.
Plate XCIX, figures 2a-b; Plate C, figures la-b.

Determinative characters—Test large; pentagonal in marginal outline, longer than broad,
broadest opposite the ends of the anterior petals, pointed anteriorly, posterior end truncated
centrally; upper surface irregularly convex, high, highest back of center, whence sloping gently
and in a straight line to the blunt, tumid anterior edge and quite steeply sad in a straight line to
the thinner, wedge- shaped posterior edge; under surface deeply concave, the concavity beginning
near the margin fond increasing at first “aacineilly then rapidly to the center. Ambulacral petals
large, broad, very tumid, almost reaching the margin, nearly closing, the posterior pair slightly
longer than the odd petal which is slightly longer than the anterior pair. Apical system central,
sloping downward anteriorly; five genital pores a short distance from the slightly depressed
madreporite. Peristome large, slightly excentric posteriorly, subpentagonal, deeply sunken;
ambulacral furrows simple, straight, reaching the margin. Periproct rather large, subcircular;
inframarginal, almost marginal.

Dimensions.—Length 112 millimeters; width 92 millimeters; height 50 millinve tenet

Description. —Only a few specimens of this handsome eed form have been dis-
covered. The test is large; pentagonal in marginal outline, the corners of the pentagon bemg
rounded and the sides straight or faintly concave; longer than broad, broadest opposite the ends
of the anterior petals, pointed anteriorly, posterior end truncated centrally; margin very thick
and rounded opposite the petals, thinner between them, thinnest along the wedge-shaped pos-
terior edge. The upper surface is irregularly convex, high, relatively higher than in other
American clypeastroid forms. The apex is slightly excentric posteriorly, being located at the
posterior part of the apical system from which point the upper surface slopes senile (the angle
being about 30° from the horizontal), and in a straight line to the wedge-shaped posterior margin.
The “oii along a longitudinal median section is therefore angular at the apex. The under
surface is strongly concave; the concavity beginning near the sagen and increasing gradually
for about half the way, then very rapidly for the rest of the way to the deeply sunken peristome,
where it is about one-half the height of the test. The rapid increase in the concavity begins
somewhat farther from the anterior end than it does elsewhere.

The ambulacral areas are wide, the dorsal portions petaloid. The petals are very large and
conspicuous, broad, very tumid, almost reaching the margin, nearly closed at the ends, the pos-
terior pair slightly longer than the odd petal which is slightly longer than the anterior pair. The
poriferous zones are wide, narrowing and converging rapidly at the ends so as to almost com-
pletely inclose the inter por iferous area, the inner row co pores notably higher than the outer row;
pores round, subequal, pairs of pores conjugated. The interporifer ous areas are very wide, very
tumid, the inner portions uniting to form a narrow tumid ring around the madreporite.

PLIOCENE ECHINODERMATA. 219

The interambulacral areas are narrow throughout their whole length, though wider between
the ends of the petals than elsewhere, much narrower than the ambulacral areas. The whole
surface of the test is thickly set with small tubercles which are somewhat larger on the under
surface.

The apical system is central, sloping downward anteriorly from the apex; the madreporite
large, pentagonal, slightly depressed. There are five genital pores situated a short distance
from the madreporite; and there are five small radial plates at the edge of the madreporite, per-
forated by minute pores.

The peristome is large, subpentagonal, slightly excentric posteriorly at the deepest point
of the deep concavity on the under surface. The ambulacral furrows are simple, straight
shallow grooves extending from the peristome almost to the margin, which are deeper midway
than toward the peristome.

The periproct is rather large, circular. inframarginal, almost marginal.

Related forms.—D. dalli is very closely related to the recent American form generally known
as Echinanthus rosaceus (which, if Duncan be followed, should be Diplothecanthus rosaceus),
differmg from it chiefly in being relatively higher, in having the apex slightly excentric posteriorly
and angular, with a straighter slope anteriorly and a steeper slope posteriorly, in having the
apical system sloping downward anteriorly, and in having the interporiferous areas more tumid
and coalescing around the madreporite. D. daili rather closely resembles in many features the
foreign forms Clypeaster crassicostatus* Agassiz, from the Miocene of Austria-Hungary, Italy,
and Corsica, but differs from it in being less elongate longitudinally and more elevated, in hav-
ing more difference between its anterior and posterior slope, and in having its petals broader,
slightly less open and somewhat longer.

Locality.—Near Fort Thompson, Caloosahatchee River, Fla.

Geologic horizon.—Caloosahatchee marl, Pliocene.

Collection —U. S. National Museum (164670). Collected by W. H. Dall, after whom the
species is named.

DipLOTHECANTHUS ROSACEUS (Lamarck).
Plate CII, figures la-b; Plate CIII, figures la—b

Echinus reticulatus Linné, 1758, Systema nature, p. 3191.
Clypeaster rosaceus Lamarck, 1840, Animaux sans vertébres, 2d ed., p. 289.
Echinanthus rosaceus A. Agassiz, 1872, Revision of the Echini, pp. 106, 311, 514.

Deseription.—This well-known recent species is so fully described elsewhere it is needless
to give a detailed description here. The specimen here figured was reported as found in the
Phocene deposits of Florida. The test is very large; pentagonal in marginal outline, the corners
of the pentagon being rounded and the sides and posterior end slightly concave; somewhat
longer than broad, pointed anteriorly; margin thick and rounded opposite the petals, less so
between them. The upper surface is convex, moderately high, of uniform height at the highest
parts of each of the petals. The apex is central, coincident with the apical system, and the
upper surface is nearly level for nearly an inch out from the center in rather steep curves along
the ambulacral areas and in steep nearly straight lines along the interambulacral areas to the
margin. The outline along a longitudinal median section is nearly level for the central third
of the length of the test whence it slopes nearly equally to each end. The under surface is
nearly flat around the margin and rather strongly concave around the peristome, where it is
less than one-half the height of the test.

The ambulacral areas are very wide, the dorsal portions petaloid. The petals are very
large, very broad, moderately tumid, well apart at the ends, subequal in length. The poriferous
zones are very wide, the inner row of pores moderately elevated above the outer.

The interambulacral areas are very narrow, especially at the margin, where they are only
about one-third as wide as the ambulacral areas.

1 See Michelin’s Monographie des Clypéastres, p. 115, Pl. XVII, figs. 1a-f.

920 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

The apical system is central, coincident with the apex, about on a level with the highest
portions of the ambulacral petals. The specimen is too weathered to permit of making out
the details.

The peristome is large, subpentagonal, central, at the deepest point of the concavity on the
under surface. The ambulacral furrows are simple, straight shallow grooves extending from
the peristome nearly to the margin.

The periproct is large, circular, inframarginal, almost marginal.

Dimensions.—Length 134 millimeters; width 116 millimeters; height 50 millimeters.

Related forms.—It is unnecessary to discuss here the related recent forms. The nearest
fossil form is Diplothecanthus dalli, which is to be distinguished by being relatively higher, in
having the apex slightly excentric posteriorly and angular, with a straighter slope anteriorly
and a steeper slope posteriorly, in having the apical system sloping downward anteriorly, and
in having the interporiferous areas more tumid and coalescing around the madreporite.

Locality —Near Labelle Landing, Caloosahatchee River, Fla.

Geologic horizon.—Pliocene (7%).

Collection.—U.S. National Museum (165693).

Order ATELOSTOMATA.
Suborder ASTERNATA.
Family CASSIDULID®.

Genus CASSIDULUS Lamarck.
CASSIDULUS BERRYI Twitchell, n. sp.
Plate CI, figures 3a-d. )

Determinative characters.—Test small, subcircular in marginal outline; upper surface much
depressed, convex; sides and ends equally and gently declining; margin angular, posterior end
rostrated; under surface concave, more so anteriorly around the peristome. Apex central;
apical system excentric anteriorly. Ambulacral areas rather broad in petaloidal dorsal portions,
very narrow above the margin. Peristome small, anteriorly excentric, pentagonal, with a
floscelle. Periproct oval, supramarginal, in a short, shallow sulcus.

Dimensions.—Length 28 millimeters; width 27 millimeters; height 11 millimeters.

Description.—The only specimen of this species so far reported was found recently in North
Carolina by E. W. Berry, of Johns Hopkins University, in whose honor the species is named.
Unfortunately, the specimen is damaged, so that a number of important details can not be made
out; but the characters which can be made out prove it to be distinct from the other American
representatives of the genus. The test is small, about an inch in diameter; subcircular in
marginal outline, the longitudinal diameter slightly exceeding the transverse. The upper sur-
face is much depressed, convex, sides and ends equally and gently declining; margin rather
sharply angular all around; posterior end rostrated and faintly notched beneath the periproct;
under surface concave, more so anteriorly around the peristome than elsewhere. The apex
is central.

The ambulacral areas are rather broad in the petaloid dorsal portions, very narrow above
the margin and actinally; the petals are rather broad, subelliptical, subequal in length, nearly
closing at the ends. The details are obscure.

The apical system is excentric anteriorly.. The details can not be made out on the specimen.

The peristome is small, anteriorly excentric, beneath the apical system, pentagonal, with a
floscelle haying prominent bourrelets.

The periproct is oval, longitudinally elongate, supramarginal, in a short, rather wide, shal-
low sulcus, which extends to and faintly notches the posterior margin.

PLIOCENE ECHINODERMATA. 221

Related forms.—The nearest related American form is Cassidulus bassleri, from which it is
readily distinguished by its more depressed form, its angular margin, and the anteriorly excentric
position of its peristome.

Locality.—Neills Eddy Landing, Cape Fear River, N. C.

Geologic horizon.—W accamaw marl, Pliocene.

Collections —U. S. National Museum; Johns Hopkins University (T 1).

Suborder STERNATA.
Family SPATANGID®.
Genus SCHIZASTER Agassiz.
SCHIZASTER (?) STALDERI Weaver.
Plate CIII, figure 2.
Schizaster (?) stalderi Weaver, 1908, California Univ. Dept. Geology Bull., vol. 5, No. 17, p. 274, Pl. XX, fig. 3.
Schizaster staldert Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 705.
Description —W eaver says:

Test distinctly cordate in form, with all of the petals deeply sunken. The depression of the anterior petal deeply
notches the anterior margin. The petals of the bivium are very short. The mouth opening is situated very far for-
ward. The anal opening is not shown. As all of the known specimens are casts, the nature of the plates of the test is
only imperiectly shown.

Dimensions —Maximum length 30.5 millimeters; maximum width 28 millimeters.
Locality —Wumboldt County, Cal.
Geologic horizon.—Wildcat series of Lawson, Pliocene.
Collection.— University of California.
39800°—15——_15

PLEISTOCENE ECHINODERMATA.
Class STELLEROIDEA.

Subclass ASTEROIDEA.
Order CRYPTOZONIA.

Family ASTERIID ®.
Genus ASTERIAS Linné.

ASTERIAS STELLIONURA Poiret.
Asterias stellionura Sears, 1905, Physical geography, etc., Essex County, Mass., pp. 369, 370.

Description.—Sears describes the discovery in 1903 in the Richard Graham clay pit at
Lynn, Mass., of a thick bed of fossil starfish, material from which was collected and sent to
A.K. Verrill, of Yale University, for identification. Of the two forms found one Is unquestionably
referred to A. stellionura. Verrill states that ‘‘the pedicellarie, both major and minor, are ©
remarkably well preserved and very characteristic,” and that “it is a very arctic species, com-
mon at Spitzbergen and the northern Norwegian coasts.”

Locality.—Richard Graham clay pit, Lynn, Mass.

Geologic horizon.—Pleistocene.

Collection.—Peabody Museum, Salem, Mass.

ASTERIAS LINCKI Miiller.
Asteracanthion lincki Sears, 1905, Physical geography, ete., Essex County, Mass., pp. 369, 370, fig. 202.

Description.—Verrill says:

The pedicellarize, both major and minor, are remarkably well preserved and very characteristic. On the Astera-
canthion the latter form large and dense clusters around all the spines. The same appears in your fossils. The major
ones are very large, ovate, subacute, especially along the adambulacral plates, but also many of the dorsal surfaces as
in your examples. Dorsal plates are very delicate and form a slender network. Adambulacral spines are small and

slender, tapered, acute, and a large tubed spine stands singly back of every fourth or fiith plate (sometimes third or
fourth) as in yours. In all of these characters and others it differs from 4. vulgaris.

Locality—Richard Graham clay pit, Lynn; Liberty Street, Danvers, Mass.
Geologic horizon.—Pleistocene.
Collection.—Peabody Museum, Salem, Mass.

Class ECHINOIDEA.

Subclass REGULARIA ECTOBRANCHIATA.
Order DIADEMOIDEA.
Suborder ECHININA.

Family TRIPLECHINID®.
Genus TOXOPNEUSTES A. Agassiz.

TOXOPNEUSTES VARIEGATUS (Lamarck).

Echinus variegatus Holmes, 1858, Post-Pliocene fossils South Carolina, Pl. II, fig. 1.
Anapesus carolinus Holmes, 1858, Post-Pliocene fossils South Carolina, Pl. II, fig. 2.
Toxopneustes variegatus A. Agassiz, 1872, Revision of the Echini, p. 168.
Description.—A. Agassiz regards the form referred by Holmes to Anapesus carolinus as
T. variegatus. No material has been available for study.
Locality Simmons Bluff, St. Paul’s, Wando, and Charleston, S. C. (Holmes).
Geologic horizon.—Pleistocene.
Collection. —Unknown.

222

PLEISTOCENE ECHINODERMATA. ORS.

Family STRONGYLOCENTROTID®.
Genus STRONGYLOCENTROTUS Brandt.
STRONGYLOCENTROTUS DROBACHIENSIS Miiller.

(2?) Echinus granulatus, Billings, 1856, Canadian Naturalist and Geologist, Ist ser., vol. 1, p. 346.
Strongylocentrotus drébachiensis Verrill, 1875, Am. Jour. Sci., 3d ser., vol. 10, p. 375.
Strongylocentrotus drébachiensis Cooper, 1894, California Min. Bur. Bull. 4, p. 32.
Description. Fragments of tests and spines regarded as representing this species have been
reported from Pleistocene deposits from Nantucket northward and also in California.
Localities —Canada (Billings); Sankaty Head, Nantucket, Mass. (Verrill); San Nicolas
Island, Cal. (Burns).
Geologic horizon.—Pleistocene.
Collection.—Unknown.

STRONGYLOCENTROTUS FRANCISCANUS A. Agassiz.

Strongylocentrotus franciscanus Arnold, 1903, California Acad. Sci. Mem., vol. 3, p. 90.
Strongylocentrotus franciscanus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706.

Description.—Arnold in discussing the occurrence of this species in the Pacific coast Pleis-
tocene says:

This is the large sea urchin of the west coast. Spines which are probably of this species have been found in the
lower San Pedro series of Deadman Island. The spines of this species are distinguishable by their large size and longi-
tudinal striations. Some of the spines found are 20 millimeters long and 3 millimeters in diameter.

Locality.—San Pedro, Cal.
Geologic horizon.—San Pedro formation (lower part), Pleistocene.
Collection.—Leland Stanford Junior University.

STRONGYLOCENTROTUS PURPURATUS (Stimpson).

Strongylocentrotus purpuratus Arnold, 1903, California Acad. Sci. Mem., vol. 3, pp. 90, 91.
Strongylocentrotus purpuratus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Description—Arnold, who mentions the discovery of spines of this species in the Cali-
fornia Pleistocene, says:

Numerous spines of this small purple sea urchin have been found in the San Pedro series. No part of the test
has ever been discovered in these deposits, to the writer’s knowledge. Several nearly perfect tests of this species were
found in the Pleistocene (lower San Pedro series) deposits at the bathhouse, Santa Barbara. A nearly periect test
was also found in the upper horizon of the San Diego formation (Pleistocene (?) ) at Pacific Beach, near San Diego.

Localities —San Pedro, Santa Barbara, and San Diego, Cal.

Geologic horizon.—San Diego formation (upper part), Plocene; San Pedro formation
(lower part), Pleistocene.

Collection.—Leland Stanford Junior University.

Subclass TRREGULARIA.
Order GNATHOSTOMATA.
Suborder CLYPEASTRINA.

Family SCUTELLID &.
DENDRASTER EXCENTRICUS (Eschscholtz).
Plate CIV, figures la-d; Plate CV, figures la-d.

Scutella striatula De Serres, 1829, Géognosie terr. tert. du midi de France, p. 156.

Scutella excentrica Eschscholtz, 1831, Zool. atlas, p. 19,P1. XX, figs. 2, 2a, 2b.

Echinarachnius excentricus Valenciennes, 1846, Voyage Vénus, Zooph., Pl. X. ,

Dendraster excentricus L. Agassiz, 1847, Cat. raisonné des échinodermes, Soc. Nat. Ann., vol. 7, p. 135.
Dendraster excentricus Gray, 1855, Cat. Recent échinoderms, p. 16.

Dendraster excentricus Stimpson, 1857, Boston Soc. Nat. Hist. Jour., vol. 6, pp. 526-527.

224 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

Scutella striatula Conrad, 1857, U. S. Pacific R. R. Expl. 32d Par. and California, vol. 7, pl. IX, figs. la, 1b; non

Dendraster excentricus Dujardin and Hupé, 1862, Hist. nat. zoophytes échinodermes, p. 564.

Scutella striatula Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2

Scutella striatula Gabb, 1869, California Geol. Survey, Paleontology, vol. 2, p. 110.

Scutella (Echinarachnius) excentricus A. Agassiz, 1872, Revision of the echini, Mus. Comp. Zoology Mlus. Cat. No. 7,
pp. 107, 524-526. Pl. XIITa, figs. 1 to 4. ;

Echinarachnius excentricus Cooper, 1888, Cat. California fossils: State Mineralogist Seventh Rept., p. 271.

Echinarachnius excentricus Gregory, 1891, Geol. Soc. America Bull., vol. 3, p. 107.

Echinarachnius excentricus Merriam, 1899, California Acad. Sci. Proc., 3d ser., Geology, vol. 1, No. 5, p. 170, Pl. XXIf,
fig. 8.

Scutella (Echinarachnius) excentricus Arnold, 1903, California Acad. Sci. Mem., vol. 3, p. 91.

(2) Echinarachnius excentricus Eschscholtz var. ivamaital 1907, U. 8. Geol. Survey Bull.-322, Pl. XXIV, fig. 8. (This
is probably a variant form of Dendraster gibbsii.)

Scutella striatula Schuchert, 1908, U. 8. Nat. Mus. Bull. 53, pt. 1, p. 594.

Echinarachnius excentricus Pack, 1909, California Univ. Dept. Biesllom Bull., vol. 5, No. 13, pp. 231-282.

Dendraster excentricus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707.

Determinative characters.—Test medium to large; subcircular to broadly subovate in margi-
nal outline, broader posteriorly than anteriorly; upper surface greatly depressed around the
margin, more or less tumid centrally; margin thin; under surface flat. Apex central or sub-
central. Apical system excentric posteriorly; from one-fourth to one-third the radius from
the center. Ambulacral petals large; posterior pair shorter than the others, less divergent,
equally divergent, or slightly more divergent than the anterior pair. Reniaeenn small, cir ealeel
central or subcentral; ambulacral furrows fork near the peristome, the branches at first diverg-
ing then converging slightly, each giving off one important and many small branches on the way
to the margin. The stronger branches continue abactinally, but they are rarely discernible
on fossil specimens. Periproct very small, circular or subelliptical, inframarginal.

Dimensions—Specimen A: Length 83 millimeters; width 83 millimeters; height 12 muli- -
meters. Specimen B: Length 97 millimeters; width 105 millimeters; height 19 millimeters.

Description—This well-known Recent form, abundant oa the Pacific coast, is so fully
described in other works, that it is necessary to give here only the special points of interest in
regard to the fossil specimens. Most of these have already been given in the determinative
characters, but a few additional details will be presented. The size varies from less than 2 to
more than 4 inches in diameter and less than one-fourth to about 1 inch in height. In marginal
outline the smaller forms are usually subcircular while the large ones are usually broadly subovate
and broader than long. The apex is usually between the center and the apical system, but is
sometimes central or slightly excentric anteriorly. The area between the ends of the petals
and the margin is wider than in forms which resemble this. The under surface is flat or slightly
concave.

The ambulacral areas are wide, widest at the margin, where they are wider than the inter-
ambulacral areas; dorsal portions petaloid, the petals somewhat variable in details. The petals
are large, the anterior three longer than the posterior pair, the odd petal longer than the anterior
paired petals, though sometimes appearing of equal length or shorter by reason of the shortening
of the distance between the pairs of pores of the poriferous zones for a greater or less distance
from the end of the petal. The anterior paired petals are straight or nearly so and more widely
divergent or equally divergent or slightly less divergent than the posterior pair. The posterior
pair is usually less widely divergent and the poriferous zones of each petal are less widely diver-
gent than in similar forms. The interporiferous areas of all the petals are rather wide and some-
what tumid.

The apical system*is excentric posteriorly, being situated from one-fourth to one-third the
distance from the center to the posterior margin; the madreporite is large and substellate with
four genital pores at the anterior points of the star, the two anterior nearer together than the
two posterior. There are also five small radial plates each perforated by a minute pore.

The peristome is central or slightly excentric posteriorly. The ambulacral furrows are simple
and straight for a very short distance from the peristome, then fork nearly symmetrically into

PLEISTOCENE ECHINODERMATA. BONS)

two strong furrows which diverge for a short distance then converge slightly and continue
nearly to the margin, giving off one large and many small branches on the way. Near the
margin the large furrows split up into many small ones which on well-preserved fossil specimens
and in recent specimens can be seen to continue over the margin and on the upper surface for a
considerable distance.

The periproct is very small, usually circular, but sometimes subelliptical by longitudinal
elongation; situated from 1 to 10 millimeters from the posterior border, being more distant in
the large specimens.

Related forms.—D. excentricus is closely related to both D. coalingaensis and D. gibbsii.

D. coalingaensis differs in beg smaller, more uniformly depressed and therefore less tumid
centrally, in having its apex more excentric posteriorly and more nearly coincident with the apical
system and its periproct usually nearer the margin. The features in which D. coalingaensis
resembles D. excentricus are so fundamental as to suggest that it is probably an ancestral form.
D. gibbsii differs from D. excentricus in having its apex and apical system much more excentric
posteriorly, its posterior ambulacral petals more widely divergent and with poriferous zones
also diverging more widely from each other as well as differing more in length and its periproct
usually nearer the posterior border. There do not appear to be any foreign forms closely related
to the present species.

Localities —San Diego (figured specimen A); Ventura County (figured specimen B); San
Luis Obispo (Conrad’s type); Riverside County; San Pedro (Cooper, Arnold), Santa Barbara .
(Gabb, Arnold); Seven Mile Beach, San Mateo County (Cooper); San Fernando, Los Angeles
County (Cooper); all in California.

Geologic horizon.—San Pedro formation, Pleistocene.

Collections.—Wagner Free Institute of Science (2473, A); U. S. National Museum; Yale
University; California Academy of Natural Sciences; Johns Hopkins University (T2,B).

Genus MELLITA Agassiz.
MELLITA PENTAPORA (Gmelin).
Plate CVI, figure 1; Plate CVII, figures la-c.

Echinus pentaporus Gmelin, 1788, Linné, Systema naturee, vol. 1, pt. 6, p. 3189.

Mellita testudinata Klein, 1734, Nat. disp. Echinodermata, p. 25, Pl. X-XJ, fig. C, D. (Copiedin Enc. M., Pl. CXLIX,
figs. 3, 4.)

Scutella quinquefora Lamarck, 1816, Animaux sans vertébres, p. 9.

Scutella quinquefora Lamarck, 1840, Animaux sans vertébres, 2d ed., p. 280.

Mellita testudinata Agassiz, 1841, Mon. échinodermes vivans et fossiles, Des scutelles, p. 40, Pl. IV, figs. 7-9.

Mellita quinquefora Agassiz, 1841, Mon. échinodermes vivans et fossiles, Des scutelles, p. 36, Pl. III.

Mellita ampla Holmes, 1847? MS.

Mellita ampla Ravenel, 1848, Echinide, recent and fossil, South Carolina, p. 2.

NMellita ampla Tuomey, 1848, Rept. Geology South Carolina, p. 205.

Mellita ampla Ravenel, 1850, Am. Assoc. Ady. Sci. Proc., vol. 3, p. 160.

Mellita ampla Michelin, 1855, Soc. géol. France Bull., 2d ser., vol. 12, p. 759.

Mellita texana Conrad, 1856, Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 316.

Mellita testudinata Desor, 1858, Synopsis des échinodermes fossiles, p. 237.

Mellita ampla Michelin, 1858, Rev. et mag. zool., 2d ser., vol. 10, pp. 362, 363, Pl. IX, fig. 1.

Mellita quinquefora var. ampla Holmes, 1860, Post-Pliocene fossils South Carolina, pp. 3, 4, Pl. I, fig. 6.

Mellita ampla, Dujardin and Hupé, 1862, Hist. nat. zoophytes échinodermes, p. 567.

Mellita pentapora Liitken, 1864, Bid. til Kunds. om Echinodermes, Vidensk. Medd. Kjgbenhayn.

Mellita texana Meek, 1864, Smithsonian Misc. Coll., vol. 7 (183), p. 2.

Mellita testudinata Agassiz, 1872, Revision of the Echini, pp. 141, 142.

Mellita testudinata Hilgard and Hopkins, 1878, Rept. Com. Engineers of Jan. 1875; suppl., pp. 28-33, 49, Pl. III, fig. 12.

Mellita pentapora Clark, 1902, U. S. Fish Com. Bull., p. 565, Pl. X.

Mellita ampla Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 708.

Determinative characters —-Test medium to very large; subpentagonal in marginal outline,
broadest opposite anterior paired petals; five long narrow lunules equal or subequal in length;
Margin thin, with a shallow notch at the anterior end; the whole form much depressed, the upper

226 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES.

surface rising gradually from the margin to the moderately elevated, anteriorly excentric apex;
under surface flat. Ambulacral petals large, the posterior pair longer than the others. Apical
system excentric anteriorly. Peristome small, subcircular, excentric anteriorly; ambulacral
furrows simple and straight near the peristome, then forking, each pair of branches diverging
and again converging near the margin. Periproct very small, elliptical, between the inner end —
of the odd lunule and the peristome.

Dimensions —Figured specimen, one of the largest found: Length 152 millimeters; width
159 millimeters; height 19 millimeters. Smaller specimen: Length 106 millimeters; width 111
millimeters; height 12 millimeters.

Description—The specimens herein described are believed to be representatives of the
recent species Mellita pentapora (Gmelin) which has been known under the names of IM. testu-
dinata Klein and M. quinguefora Lamarck. Evidently, as Holmes recognized, the conditions
were especially favorable to development along the South Carolina coast during Pleistocene
time, a fact which is shown by the large size of the molluscan forms as well as by the Echinide.

As this well-known recent species is fully described in other works, it is necessary to give
here only the special points of interest in regard to the specimens occurring as fossils, Conrad’s
species Mellita texana, of which what is probably the type is in the collection of the Academy
of Natural Sciences of Philadelphia, presents no marked and constant points of difference
from the recent species and therefore can not be recognized. Holmes’s variety ampla is not
entitled to separate recognition and description, as, aside from the unusual size of the South
Carolina specimens, there are no decided and constant differences. Some specimens of the
so-called variety ampla present differences in regard to the lunules which make them appear
varietal in value, but a careful study of the large number of specimens in the collections of the
United States National Museum and the Johns Hopkins University has demonstrated that
the form of the lmules is so variable as to be unsafe as a feature for separation. This
species is very abundant and occurs in a beautiful state of preservation at a few localities in
South Carolina, but is rare elsewhere. Most of the important features of the test have been
set forth in the determinative characters, but a few additional details will be given here. The
size of the fossil forms from South Carolina is very great, ranging from 4 to 7 inches in diame-
ter and from 4 to 3 inch in height, while those from Texas are rather small, being between 2 and
3 inches in diameter, which is about the same as that of the average recent forms. The test is
usually slightly broader than long. The margin is truncated and especially thin posteriorly.
The lunules are long narrow slits of about the same width from end to end, bluntly rounded
at the ends, the length and width quite variable even on the same specimen, the odd posterior
lunule usually wider and of equal length or sightly longer or shorter than the rest; the average
length in the South Carolina forms is about 1 inch and the width one-eighth of an inch. The
petaloid region is large; the petals are long and wide, subelliptical to subspatulate in form,
extending about halfway to the margin, well open at their ends, with very broad poriferous
zones which about equal in width the interporiferous areas. The apical system is large; madre-
porite large and stellate; four genital pores at the tips of the points of the star, the two pos-
terior farthest apart; five small pores at inner ends of reentrant angles of the star. The main
branches of the ambulacral furrows are more or less flexuous and each branch gives off one
important lateral branch as it bends to approach the margin. The undersurface, though flat
in general, has shallow grooves along the middle of each ambulacrum.

Related forms—The only American fossil form which is closely related to the present
species is Mellita caroliniana which, however, is readily distinguished by its having a sixth
lunule in the middle of the anterior ambulacrum, by having its ambulacral lunules nearer the
margin and its posterior paired lunules longer than the anterior pair; and having the relative
height of its test less than in Jf. pentapora. :

Localities —Simmons Bluff, Youngs Island, Wadmalaw Sound, S. C.; Brunswick Canal,
Glynn County, Ga.; Texas ( %).

Geologic horizon.—Pleistocene.

PLEISTOCENE ECHINODERMATA, 227

Collections.—Johns Hopkins University (T 2, T 4); American Museum of Natural History;
U.S. National Museum; Wagner Free Institute of Science; Academy of Natural Sciences of
Philadelphia.

Order ATELOSTOMATA.,

Suborder STERNATA.
Family SPATANGID ©.
Genus SCHIZASTER Agassiz.
SCHIZASTER ATROPOS (Lamarck).

Schizaster atropos Ravenel, 1848, Echinidee, recent and fossil, South Carolina, p. 4.
Schizas’er atropos Holmes, 1858, Post-Pliocene fossils South Carolina, pp. 5, 6, Pl. II, fig. 3.
Mera lachesis Desor, 1858, Synopsis échinides fossiles, p. 394.
Schizaster atropos A. Agassiz, 1874, Revision of the Echini, p. 751.
Description.—No material has been found that can be referred to this species.
Locality —Abbapoola Creek, Johns Island, 8. C. (Holmes).
Geologic horizon.—Pleistocene.
Collection.— Unknown.

leAL A CU Ds.

39800°—15—16

229

MONOGRAPH LIV PLATE |

U. S. GEOLOGICAL SURVEY

TRIASSIC CRINOIDEA AND ECHINOIDEA.

PEATE, 1

Isocrrnus smirHi Clark, n. sp. (p. 21).
U.S. Nat. Mus. 31184, type.

Fieure la. Articular surface of a detached joint of the column, x 4.
1b. Lateral view of a detached joint of the column, 4.

TsocrINUS CALIFORNICUS Clark, n. sp. (p. 21).
U.S. Nat. Mus. 31185, type.

Ficure 2a. Articular surface of a detached joint of the column, X 6.
2b. Lateral view of a portion of the column, X 6.
2c. Several specimens of column joints.

Encrinus uyartti Clark, n. sp. (p. 22).
U.S. Nat. Mus. 31186, type.

Figure 8a. Articular surface of a detached joint of the column, x 12.
3b. Lateral view of a portion of the column, x 13.

AsPIDURA (?) IDAHOENSIS Clark, n. sp. (p. 23).

U.S. Nat. Mus. 31187, type.
Figure 4. Cast of two specimens.

CIDARIS SHASTENSIS Clark, n. sp. (p. 238).
U.S. Nat. Mus. 31188, type.

Fieure 5. Fragment of interambulacral plate, x 3.

CIDARIS DILLERI Clark, n. sp. (p. 23).

U.S. Nat. Mus. 31189, type.
Fiaure 6. Portion of test.

230

MONOGRAPH LIV PLATE II

U. S. GEOLOGICAL SURVEY

JURASSIC CRINOIDEA.

Ficure 1.
la.

2
Zz

9-13.

PLATE II.

Tsocrints KNIGHTI Springer (p. 25).
U.S. Nat. Mus. Springer A-H, type. (After Springer.)

Large specimen A; with bifurcating arms complete and part of stem; cirri mostly lost.
Syzygy at I1[Br 79+80 of same specimen.

. Large specimen, B, with stem 140 millimeters, and part of arms. Some arms of another individual

attached.

. Detail of stem at ‘“‘a” of same specimen, showing interarticular pores, & 2.

. Detail of same at ‘‘b’’, showing cirrus sockets, X 2.

. Small specimen, C, with part of arms, some not bifurcating.

. Calyx and lower III Br of same specimen, showing form and proportions of basal and radial plates, x 2.

. Small specimen, D, with part of arms, one with an axillary, and some apparently simple.

. Small specimen, E, with two arms simple and one bifurcating at 23d IIIBr, stem detached, exposing

infrabasals.

. Basal view of same specimen, showing intrabasals, « 4.
. Portions of different stems, F, G, H, showing cirri.
. The longest cirrus on specimen G, X 2.

Weathered stem joints associated with the other specimens: 9, 10, 11 are mature internodals; 12 is the
proximal face of a nodal incised by the cirrus sockets; 13 is a deeply stellate joint from the youngest part
of the stem; all X 2.

231

MONOGRAPH LIV PLATE Ill

U. S. GEOLOGICAL SURVEY

JURASSIC CRINOIDEA AND STELLEROIDEA.

LeAbyewisy JUG.

Tsocrinus KNIGHTI Springer (p. 25).
U.S. Nat. Mus. 682.

Fieure la. Column with attached pinnules.
1b. Articular surface of a detached joint of the column, x 4.
le. Lateral view of a portion of the column, 4.
ld. Enlarged pinnule, X 2.

PENTACRINUS AsTERISCUS Meek and Hayden (p. 26).
U.S. Nat. Mus. 220, type. (After Meek and Hayden.)
Figure 2. Upper surface of a detached joint, x 5.
PENTACRINUS WHITEI Clark (p. 27).
U.S. Nat. Mus. 8588, type.

Figure 3a. Articular surface of a detached joint of the column, x 2.
3b. Same, X 2.
3c. Lateral view of a portion of the column.
PENTACRINUS SHASTENSIS Clark, n. sp. (p. 28).
U.S. Nat. Mus. 31180, type.
Fieure 4. Articular surface of a detached joint of the column, x 3.
OPHIOGLYPHA UTAHENSIS Clark, n. sp. (p. 29).
U.S. Nat. Mus. 22839, type.
Figure 5. Upper surface of specimen, 3.
Asrertias (7) puprum Whitfield (p. 28).
U.S. Nat. Mus. 12325, type.

Ficure 6. Gutta-percha cast of three individuals.
939

ave

MONOGRAPH LIV PLATE IV

U. S. GEOLOGICAL SURVEY

JURASSIC ECHINOIDEA.

Fiaure la,
lb.
le.

Figure 2a,
2b.

eA LV
CIDARIS CALIFORNICUS Clark (p. 30).
U.S. Nat. Mus. 30184, type.
Spine.
Same.
Articular surface of 1b, x 2.
CIDARIS TAYLORENSIS Clark (p. 30).
U.S. Nat. Mus. 30183, type.

Fragment containing two contiguous interambulacral plates of the same series.
Spine. .
CIDARIS PLUMASENSIS Clark, n. sp. (p. 31).

U.S. Nat. Mus. 31191, type.

Ficure 3. Portion of interambulacral area,

Ficure 4a.
4b.
Ac.
4d.

4e.
4f.

Boe

4h.

41.

HeMICIDARIS INTUMESCENS Clark (p. 31).
U.S. Nat. Mus. 30187 and 30188, types.

Upper surface of the test. Partly restored.
Lower surface of the test. Partly restored.
Lateral view of the same. Partly restored.
Two interambulacral plates, < 5.

Lower portion of interambulacrum, % 5.
Upper portion of the same, 5.

Portion of ambulacrum, x 4.

Tubercle from above, 8.

Lateral view of the same, x 8.

bo
WwW
oo

MONOGRAPH LJV_ PLATE V.

U. S. GEOLOGICAL SURVEY

JURASSIC ECHINOIDEA.

PLATE VY.
PSEUDODIADEMA EMERSONI Clark (p. 32).
U.S. Nat. Mus. 30186, type.

Fieure la, Lateral surface of the test.
1b. Portion of interambulacrum, 3.
lc. Portion of ambulacrum, x 3.
1d. Tubercle from the side, x 5.
le. The same from above, x 5.

SroMEecHINUS Hyattt Clark (p. 33).
U.S. Nat. Mus. 30185, type.

Ficure 2a. Lateral surface of the test, slightly distorted.
2b. Portion of ambulacrum, x 4.
2c. Portion of interambulacrum,
2d. Tubercle from above, X 8.
2e. The same from the side, X 8.

Hoxiecrypus PEALE! Clark, n. sp. (p. 33).

U.S. Nat. Mus. 31192, type.

Figure 3a, Lateral surface of the test.
3b. Upper surface of the test.
Ho.Lecryeus CRAGINI Clark, n. sp. (p. 34).

U.S. Nat. Mus. 31193, type.
Ficure 4. Upper surface of the test.
234

MONOGRAPH LIV PLATE VI

U. S. GEOLOGICAL SURVEY

S CRINOIDEA.

CRETACEOU

PAM ovale

PENTACRINUS TEHAMAENSIS Clark, n. sp. (p. 35).
U.S. Nat. Mus. 31194, type.
Ficure 1. Articular surface of a detached joint of the column, X 2.
PENTACRINUS BRYANI Gabb (p. 35).
Acad, Nat. Sci. Philadelphia 1458, type.

Figure 2a. Lateral view of a portion of a joint column.
2b. Articular surface of the column.

Uryracrinus socratts Grinnell (p. 36).
Mus. Comp. Zoology, Cambridge. (Figures after Springer.)

Ficure 8a. Monocyclic; regular; centrale of maximum size.

3b. Monocyclic; irregular; double centrale.

3c. Dicyclic; irregular; double centrale and 1 IB.

3d. Dicyclic; regular; IBB fully developed.

3e. Specimen, with three individuals, showing dicyclic and monocyclic forms of base, and maximum and
small size, lying together in close contact on the slab; the black membrane lining the calyx is also shown
at the edge of the broken plates.

3f. Uintacrinus westfalicus Schlueter. Figure of the type specimen for comparison (after Schlueter).

3g. Specimen laterally compressed; showing the fixed and proximal free pinnules, and the anal tube in natural
position.

3h. Articulating surfaces of brachials, enlarged 2.2; to show the diagonal direction of the fulcral ridges.

235

MONOGRAPH LIV PLATE VII

U. S. GEOLOGICAL SURVEY

inal

waved BAUREFUDIVEIIE

CRETACEOUS CRINOIDEA AND STELLEROIDEA.

Fiacure la.
1b.

Ie,

Ficure 2a.
2b.

Fiaure 4a.
4b.

4c.

Figure 5a.
5b-g.

PLATE VII.

UINTACRINUS SOCIALIS Grinnell (p. 36).

U.S. Nat. Mus. 8044.
Lateral view of the test.
Test showing pinules.
Part of test, 2.

MARSUPITES AMERICANUS Springer (p. 39).
Side of calyx, with bases of arms, and a strong interbrachial passing in between them.

Base of the same.
Collection of Frederick Brawn.

. Infrabasal plate of much larger specimen.

Collection of Frank Springer.
RuiZzocrkINUS ALABAMENSIS (De Loriol) (p. 39).
Cincinnati Soc. Nat. Hist., type.
Side of the basal cone.

Upper surface of the same.
Lower surface of the same.

Ruizocrrnus cyirnpricus Weller (p. 40).

New Jersey Geol. Survey, type.

Lateral view of a complete body, X 2.
Various sides of several column joints, probably belonging to this species (enlarged).
Univ.

ASTROPECTEN (?) MOoNTANUS Douglas (p. 41).

Carnegie Mus. 601, type.

Ficure 6. Impression of skeleton.

PENTAGONASTER BROWNI Weller (p. 41).

Walker Mus., Chicago, type.

Figure 7. Dorsal surface (?).
236

Johns Hopkins

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE VIII

CRETACEOUS STELLEROIDEA.

PLATE VIII.
GONTASTER MAMMILLATA Gabb (p. 42).
Acad. Nat. Sci. Philadelphia 1457, type.

Figure la-g. Various sides of four different plates, X 2.
lh. Surface of plate, X 20.

PENTACEROS ASPERULUS Clark (p. 42).

Johns Hopkins Uniy. T 3014, type.
Fiaure 2a. Top of plate.
2b. Side of plate.

OPHIOGLYPHA TEXANA Clark (p. 43).

U. S. Nat. Mus. 21884, type.
Figure 3a. Oral surface.
3b. Portion of aboral surface, x 5.
3c. Portion of oral surface, 5.

OPHIOGLYPHA BRIDGERENSIS (Meek) (p. 43).

U.S. Nat. Mus. 7820, type.
Figure 4a. Skeleton, natural size.
4b. Portion of the upper surface.
237

39800°—15 Ale

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE IX

CRETACEOUS ECHINOIDEA.

PIGADE EX:

CIDARIS TEHAMAENSIS Clark, n. sp. (p. 44).

U.S. Nat. Mus. 31195, type.
Ficure 1. Lateral view of spine.

CmaARIS TEXANUS Clark (p. 45).

U.S. Nat. Mus. 8381, type.
igure 2a. Test, natural size.

2b. Test, restored, slightly enlarged.
2c. Arrangement of the interambulacral plates in the vicinity of the apical disk, with adjacent ambulacral

plates. Slightly enlarged.
2d. Portion of ambulacrum, X 6.
2e. Interambulacral plate, slightly enlarged.
2f. Tubercle, X 3.

Crparis watcorttr Clark (p. 45).

Acad. Nat. Sci. Philadelphia 1451, type.

Fieure 3a. Portion of the test.
3b. Interambulacral plates, X 2.
3c. Portion of ambulacrum, x 8.
3d. Tubercle, * 4.

CrDARIS SPLENDENS Morton (p. 46).

Johns Hopkins Univ. T 3001.
Ficure 4a. Upper surface of the test.
4b. Lateral surface of the test.

CipARIS SPLENDENS Morton (p. 46).

Acad. Nat. Sci. Philadelphia, type.
Fieure 5a. Portion of test.
5b. Interambulacral plate, < 2.
5c. Portion of ambulacral area, * 5.
5d. Tubercle, lateral view, X 2.
5e. Spine, X 2.
5f. Base of same, X 6.

CmpARIS SPLENDENS Morton (p. 46).

Johns Hopkins Univ. T 3002.
Ficure 6. Genital plate.

CrpaRIs DIxTENsts Clark, n. sp. (p. 47).

Geol. Survey Texas, type.
Fieure 7a. Interambulacral plate.
7b. Same.

238

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE X

CRETACEOUS ECHINOIDEA.

PLATE X.

LerocrpARIs HEMIGRANOSUS (Shumard) (p. 48).

U.S. Nat. Mus. 21768.

Fiaure la. Upper surface of the test, X 4.
lb. Lower surface of the test, %.
lc. Lateral surface of the test, < 3.
1d, Interambulacral plate.
le. Portion of ambulacrum, x 5.
lf. Tubercles, < 2.
1g. Apical system.
239

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XI

CRETACEOUS ECHINOIDEA.

PEATE Xa:

LerocipARIs HEMIGRANOSUS (Shumard) (p. 48).
U.S. Nat. Mus. 21768.

Ficure la. Upper surface of the test restored, natural size.
1b. Lateral view of the same.
240

U. S. GEOLOGICAL SURVEY

MONOGRAPH LIV PLATE XiIl

CRETACEOUS ECHINOIDEA.

Ficure la.
lb.
le.
ills
le.

iby

1g.
th.

bt,

PLATE XII.

SALENIA TEXANA Credner (p. 49).

U.S. Nat. Mus. 8329, specimen A.

Lateral view of the test slightly enlarged.
Upper surface of the test restored, slightly enlarged.
Lower surface of the same.
Lateral surface of the same.
Interambulacrum, 3.
Ambulacrum, X 4.
Portion of the same, < 10.
Tubercle.
Apical system, X 14.

241

U S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XIII

CRETACEOUS ECHINOIDEA.

PEATE Xin:

SALENIA TUMIDULA Clark (p. 50).

Acad. Nat. Sci. Philadelphia 1448, type.

Ficure la. Upper surface of the test, x 2.
1b. Under surface of the test, 2.
1c. Lateral surface of the test, X 2.
1d. Interambulacrum, x 5.
le. Single plate of same, x 8.
lf. Portion of ambulacrum, 10.
lg. Apical system, X 14.
lh. Genital plate of same, 6.
li. Peristome, 3.
1j. Tubercle, X 10.

SALENIA BELLULA Clark (p. 51).

Acad. Nat. Sci. Philadelphia 1446, type.

Ficure 2a. Upper surface of the test, < 2
2b. Under surface of the test, 2.
2c. Lateral surface of the test, x 2.
2d. Three interambulacral plates, x 6.
2e. Three ambulacral plates, * 10.
2%. Apical disk enlarged.
2¢. Tubercle, X 10.
242

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XIV

CRETACEOUS ECHINOIDEA.

PLATE XIV.

SALENIA TEXANA Credner (p. 49).
Johns Hopkins Uniy. T 3003, specimen B.

Figure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Lateral surface of the test.

HyPoDIADEMA ELEGANS Clark, n. sp. (p. 52).

U.S. Nat. Mus. 31196, type.

Fiaure 2a. Upper surface of the test.
2b. Lateral surface of the test.

GontopyGus zirrett Clark (p. 52).

U.S. Nat. Mus. 12234, type.
Ficure 3a. Upper surface of the test.

3b. Lower surface of the test.
3c. Lateral surface of the test.

MONOGRAPH LIV PLATE XV

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PILATE Vi.
Gontorycus zirreLt Clark (p. 52).

U.S. Nat. Mus. 12234, type.
Ficure la. Upper surface of the test.
lb. Lower surface of the same.
le. Interambulacrum, x 3.
1d. Ambulacrum, 3.
le. Side of tubercle, * 10.
lf. Apical system, X 4.
lg. Portion of interambulacrum, x 4.
1h. Lower portion of ambulacrum, > 10.

244

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XVI

Wy

CRETACEOUS ECHINOIDEA.

Fieure la.
lb.
ICs
ld.
le.

i.

FIGURE 2a.
2b.

2c.

39800°—15

PLATE XVI.

LEPTARBACIA ARGUTUS Clark, n. sp. (p. 53).

Johns Hopkins Univ. T 3004, type.

Upper surface of the test.

Lateral surface of the test.

Apical system, X 8.

Portion of ambulacrum, 8.
Portion of ambulacrum, 15.
Portion of interambulacrum, X 4.

OrRTHOPSIS PLANULATA Clark, n. sp. (p. 54).
Johns Hopkins Univ. 73005, type.

Upper and lower surfaces of two forms.
Lateral surface of the test.
Portion of ambulacrum, X 6.

18

245

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XVII

a

Ly

i: >
\ oO aS
ie ao i)

ae i

CRETACEOUS ECHINOIDEA.

PLATE XVII.

ORTHOPSIS OCCIDENTALIS Cragin (p. 54).

Geol. Survey Texas, type.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
1c. Lateral surface of the test.
1d. Ambulacrum, X 3.
le. Portion of ambulacrum, X 6.
1f. Portion of interambulacrum, X 3.
lg. Portion of apical system, X 4.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XVIII

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

la.
Tb.
le.
ld.
le.

if.

lg.
th.

1b,

PLATE XVIII.

PsEUDODIADEMA TEXANUM (Roemer) (p. 55).

U.S. Nat. Mus. 31197.

Upper surface of the test, x 2.
Lower surface of the same, X 2.
Lateral surface of the same, X 2.
Interambulacrum, 4.
Ambulacrum, x 4.

Three interambulacral plates, X 8.
Tubercle, X 12.

Portion of interambulacrum, * 8.
Portion of ambulacrum, x 8.

HETERODIADEMA ORNATUM Clark, n. sp. (p. 56).

Johns Hopkins Uniy. T 3006, type.

. Upper surface of the test.

2b. Lower surface of the test.

. Lateral surface of the test.

. Portion of ambulacrum, 10.

. Portion of interambulacrum, * 10.
[. Lateral view of tubercle, 20.

247

U. S. GEOLOGICAL SURVEY

MONOGRAPH LIV PLATE XIX

CRETACEOUS ECHINOIDEA.

PLATE XIX.
PSEUDODIADEMA DIATRETUM (Morton) (p. 56).

Acad, Nat. Sci. Philadelphia 1471, type.

Ficurw la. Lower surface of the test.
1b. Lateral view of the test.
le. Two interambulacral plates, x 5.
1d. Three ambulacral plates, x 8.
le. Same, x 8.
lf. Tubercle, x 8.

CypHosoMA HILLi Clark (p. 59).
U.S. Nat. Mus. 8311, type.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Upper portion of an ambulacrum, x 5.
2e. Three plates of the same, X 8.
2f. Three interambulacral plates, « 4.
2g. Tubercle.
CorrosoMA SPECIOSUM Clark (p. 61).
Acad. Nat. Sci. Philadelphia 1468, type.

Figure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Upper portion of an interambulacrum, 4.
3e. Three plates of the same, < 5.
3f. Three plates of ambulacrum, x 4.
3g. Same, X 4.
3h. Tubercle, 10.

248

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XX

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

FIGURE

la.
Ib.
le.
1d.

2a.
2b.

9

3a.
3b.
3c:

ac.
2d.
2e:

PLATE XX.

CorraLpiA ROTULA Clark, n. sp. (p. 57).
Johns Hopkins Univ. T 3007, type.

Side of test of large specimen.
Side of test of small specimen.
Portion of ambulacrum, 10.
Portion of interambulacrum, 10.

DipLopopia TAFFI Cragin (p. 58).

Geol. Survey Texas, type.

Upper surface of the test.

Lower surface of the test.

Lateral surface of the test.
Portion of ambulacrum, X 5.
Portion of interambulacrum, x 5.

DrPLoPopIA STREERUVITZI Cragin (p. 58).

Geol. Survey Texas, type.

Upper surface of the test.
Portion of ambulacra, 8.
Portion of interambulacrum, 8.

MONOGRAPH LIV PLATE XxI

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PILATE DEX,

CyPHOSOMA TEXANUM Roemer (p. 60).
U. 8. Nat. Mus. 9838.

Figure la. Upper surface of the test.
lb. Lower surface of the test.
le. Lateral surface of the test.
1d. Tubercle, X 10.
le. Ambulacrum, x 3.
1f. Portion of interambulacrum, x 3.
lg. Portion of ambulacrum, x 8.

CyPHOSOMA VOLANUM Cragin (p. 61).
Geol. Survey Texas, type, specimen A.

Figure 2a. Upper suriace of the test, « 2.
2b. Lower surface of the test, « 2

CYPHOSOMA VOLANUM Cragin (p. 61).
Geol. Survey Texas, type, specimen B.

Figure 3. Upper surface of the test.
250

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXII

CRETACEOUS ECHINOIDEA.

Figure la

FIGURE

lb.
es
ld.
le.

BEATE: XXT

CoprosomMA MORTONI (De Loriol) (p. 62).
Collection P. de Loriol, type.

. Upper surface of the test.

Lateral surface of the test.

Three ambulacral plates, x 8.
Interambulacrum, X 3.

Three interambulacral plates, 6.

PSAMMECHINUS CINGULATUS Clark (p. 63).

Acad. Nat. Sci. Philadelphia 1467, type.

. Upper surface of the test.

2b. Lower surface of the test.

. Lateral view of the test.

. Interambulacrum, x 5.

. Three plates of the same X 8.
. Ambulacrum, x 5.
. Four plates of the same, x 8.

2h. Peristome, x 2.

21. Tubercle, * 20.

251

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XxXIll

CRETACEOUS ECHINOIDEA.

PATE XOX:

PEDINOPSIS SYMMETRICA (Cragin) (p. 64).

Geol. Survey Texas, type.

Figure la. Upper surface of the test.

lb. Lower surface of the test.

le. Lateral surface of the test.

1d. Apical system, 5.

le. Ambulacrum, 3.

lf. Portion of ambulacrum, 8.

lg. Interambulacrum, x 3.

lh. Portion of interambulacrum, x 8.

252

MONOGRAPH LIV PLATE XXIV

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PLATE XXIV.

PrEprnopsis Pponpr Clark (p. 65).

Johns Hopkins Univ. T 3008, type.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
le. Lateral view of the test.
1d. Four ambulacral plates, x 4.
le. Four interambulacral plates, x 2.

BorriopyGus ALABAMENSIS Clark (p. 68).

Acad. Nat. Sci. Philadelphia, type.

FicureE 2a. Upper surface of the test.

2b. Lower surface of the test.

2c. Lateral surface of the test.

2d. Portion of an ambulacrum at base of petaloidal region, X 3.

2e. Same in center of petaloidal region, < 6.

2f. An interambulacral plate, x 3.

39800°—15——19 253

MONOGRAPH LIV PLATE XXV

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

Fiaure la
1b

le.

FIGURE 2a

FIGURE 3a
3b
3c

JPL; BOVE

Mrcropsis LINEATUS Clark, n. sp. (p. 63).

U.S. Nat. Mus. 31198, type.
. Upper surface of the test.
. Lower surface of the test.
Lateral surface of the test.

Horecrypus. PLANATUS Roemer (p. 65).
U.S. Nat. Mus. 12236, figured specimen A.

. Upper surface of the test restored.
. Lower surface of the test restored.

2c. Lateral surface of the test restored.

. Two interambulacral plates, x 3.
Portion of the ambulacrum, x 5.
Apical system, 5.

HoLectypus PLANATUS Roemer (p. 65).

U.S. Nat. Mus. 12236, figured specimen B.
. Upper surface of the test.
. Lower surface of the test.
. Lateral surface of the test.

Horectypus PLANATUS Roemer (p. 65).

Johns Hopkins Univ. T 3008, figured specimen D,

Ficure 4. Lateral surface of the test.

254

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXVI

Wie Y

PN

CRETACEOUS ECHINOIDEA.

Fieure la

lb.

le
1d
le

PLATE XXVI.

Horrcryrus PLANATUS Roemer (p. 65).

Geol. Survey Texas, figured specimen C,

. Upper surface of the test.

Lower surface of the test.

. Apical system, X 5.

. Portion of ambulacrum, x 3.

. Portion of interambulacrum, X 3.

MONOGRAPH LIV PLATE XXVII

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PLATE XXVII.

PyrinaA PARRY! Tall (p. 67).

U.S. Nat. Mus. 9854.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
c. Lateral surface of the test.
ld. Posterior surface of the test.
le. Portion of ambulacrum, x 5.
lf. Portion of ambulacrum, x 1.
lg. Two interambulacral plates, 3.
h. Portion of interambulacral plate.
li. Apical system.
1j. Portion of madreporite.

ECHINOBRISSUS ANGUSTATUS Clark, n. sp. (p. 69).

Johns Hopkins Univ. T 3009, type.
Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

CASSIDULUS CONOIDEUS Clark, n. sp. (p. 80).

U.S. Nat. Mus. 31199; type.
Figure 3a. Upper suriace of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.

256

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXVIII

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

FIGURE

la.
1b.

le.

ld.

le.
li.

lg.

3a
3b
3c

PLATE XXVIII.
EcHINOBRISSUS EXPANSUS Clark (p. 69).
Acad. Nat. Sci. Philadelphia 1465, type.

Upper surface of the test.

Lower surface of the test.

Lateral surface of the test.

Posterior surface of the test.

An interambulacral plate, X 3.

Portion of the petaloidal region of the right anterolateral ambulacrum, x 8.
Apical system, X 5.

ECHINOBRISSUS TEXANUS Clark (p. 70).

U.S. Nat. Mus. 20266, type.

a. Upper surface of the test.

b. Lower surface of the test.

. Lateral surface of the test.

d. Posterior surface of the test.

. Portion of the right anterolateral ambulacrum, x 10.
. Four interambulacral plates, < 5.

TREMATOPYGUS CRUCIFERUS (Morton) (p. 71).

Acad. Nat. Sci. Philadelphia 1464, type.

. Upper surface of the test.
. Lower surface of the test.
. Lateral surface of the test.
257

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXIX

CRETACEOUS ECHINOIDEA.

PLATE XXIX.

TREMATOPYGUS CRUCIFER (Morton) (p. 71).
Acad. Nat. Sci. Philadelphia 1464, type.

Ficure la. Posterior surface of the test.
1b. Lower portion of the petaloidal region of the right posterolateral ambulacrum, <5.
lc. Several plates of the same, < 10.
Id. Apical system, x 5.
le. Tubercle from above, 20.
lf. Lateral view of the same, x 20.

CaTOPyGUs OVvIFroRMIS Conrad (p. 72).
Acad. Nat. Sci. Philadelphia 1477, type.

Fiagure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
2e. Portion of right posterolateral ambulacrum, X 3.
2f. Several plates of the same, 10.

CaroryGus PusItLus Clark (p. 73).

U.S. Nat. Mus. 2210, type.
Ficure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.

CaropyGus wILiiAmMst Clark (p. 73).

Johns Hopkins Univ. T 3010, type.
Figure 4a. Upper surface of the test.
4b. Lower surface of the test.
4c. Lateral surface of the test.
4d. Posterior surface of the test.

258

MONOGRAPH LIV PLATE XXX

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PLATE XXX.

CASSIDULUS FLOREALIS (Morton) (p. 74).

Acad. Nat. Sci. Philadelphia 1495, type.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.
le. Right posterolateral ambulacrum, X 3.
lf. Several plates in the petaloidal region of the same, x 8.
lg. Same, lower surface, 8.
lh. Posterior interambulacrum, x 2.
li. Single plate, x 4.
1j. Apical system, > 5.
1k. Tubercle from above, 20.
1l. Lateral view of the same, X 20.

CassIDULUS 2QUOREUS Morton (p. 75).
Acad. Nat. Sci. Philadelphia 1475, type.

Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
. Anterior ambulacrum, * 2.
Several plates, petaloidal region of the same, X 8.
Same, oral region, x 8.
. Apical system, 5.
Diagram showing the arrangement of the plates about the peristomial opening, > 2.

bo
D

i

mag

b bh bw bv

—

259

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXXI

BoOSy)
vue ye

CRETACEOUS ECHINOIDEA.

PEA, SOS
CASSIDULUS MICROCOCCUS Gabb (p. 76).
Acad. Nat. Sci. Philadelphia 1480, type.

Ficure la. Upper surface of the test.
lb. Lower surface of the test.
lc. Lateral surface of the test.
ld. Posterior surface of the test.
le. Anterior ambulacrum at the base of the petaloidal region, < 2.
lf. Several plates in petaloidal region of the anterior ambulacrum, X 8.
lg. Oral portion of an ambulacrum, 8.
th. Apical system, 5.
li. Surface of an interambulacral plate, x 20.

CASSIDULUS SUBQUADRATUS Conrad (p. 77).

U.S. Nat. Mus. 31200.
Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

2d. Posterior surface of the test.
vo

2e. Lower portion of the petaloidal region of the right anterolateral ambulacrum, % 2.
2f. Oral portion of an ambulacrum, x 5.
2g. Apical system, X 8.

260

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXXII

Se

Yy )
I Wp, My i
i,

Wy

=

==
= =S=SS
—S =,
—— SS

iN 1

fh iy, AN
aa
\ ‘ CA

a

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

la.
lb.
ies
ld.
le.

if.

le.

th.

hi.

7

1k.

PLATE XXXII.

CaAssIDULUS suBCONICUS Clark (p. 77).

U.S. Nat. Mus. 20264, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Anterior ambulacrum, * 2.
Several plates of the petaloidal portion, x 8.
Same, phylloidal portion, x 6.

Diagram showing the arrangement of the plates around the peristomial opening, x 2.

Interambulacral plate, x 5.
Apical system, 5.

CassIpULUS PORRECTUS Clark (p. 78).

U.S. Nat. Mus. 21890, type.

. Upper surface of the test
. Anterior ambulacrum, 14.

89800°—15——20

U, S, GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXxXiill

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

Ja

Ib.
slick
ld.
le.

i.

PLATE XXXIII.
CASSIDULUS PORRECTUS Clark (p. 78).

U.S. Nat. Mus. 21890, type.

. Posterior surface of the test.

Lower surface of the test.

Lateral surface of the test.

Lower portion of petaloidal region, 5.
Central portion of the same, X 5.

Three interambulacral plates, 2.

CASSIDULUS STANTONTI Clark (p. 79).

U.S. Nat. Mus. 20260, type.
. Upper surface of the test, 2.
. Lower surface of the test, * 2.

. Lateral surface of the test, 2.

. Posterior surface of the test, & 2.
262

U. S. GEOLOGICAL SURVEY

MONOGRAPH LIV PLATE XXXIV

EE
LES
yy

GE
ies

fs

ee

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

FIGURE

la.
lb.
le.
1d.
le.

Lf.

2a.
2b.

Ce

3a.
3b.

PLATE XXXIV.
CASSIDULUS INTERMEDIUS Slocum (p. 79).

Field Mus. P 10346, type.
Upper surface of the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.
Portion of left anterior ambulacrum at base of petaloidal region, 5.
Same, phylloidal portion, < 5.

CASSIDULUS HEMISPHERICUS Slocum (p. 80).

Field Mus. P. 10347, type.
Upper surface of the test.
Lateral surface of the test.
Portion of anterior ambulacrum at base of petaloidal region, < 5.

HonasrER stMPpLEX Shumard (p. 85).
U.S. Nat. Mus. 8382, figured specimen A.

Upper surface of the test.
Lower surface of the test.

MONOGRAPH LIV PLATE XXXV

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PLATE XXXV.

ANANCHYTES OVALIS Clark (p. 81).
Johns Hopkins Univ. T 3011, type.

Fiaure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Lateral surface of the test.
1d. Anterior surface of the test.
le. Posterior surface of the test.
If. Apical system, X 5.
lg. Ambulacral plates, < 5.
lh. Interambulacral plates, 3.

ANANCHYTES TEXANA Cragin (p. 82).

Geol. Survey Texas, type.

Ficure 2a. Lower surface of the test.
2b. Portion of ambulacrum, X 2.
2c. Portion of interambulacrum, 2.

264

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXXVI

Wan ets
FWA NORE
WSK WS XW

\

\

AINA

se: Tm
\\\ AN

Pil

NAIL

I

ih
i

CRETACEOUS ECHINOIDEA.

Figure la.

lb.

FIGURE 2a.
2b.
2c.
2d.

2e.

2f-

Io
t3)

FIGURE 3a.
3b.
3c.

PLATE XXXVI.
ANANCHYTES TEXANA Cragin (p. 82).

Geol. Survey Texas, type.
Anterior surface of the test.
Lateral surface of the test.

CARDIASTER CrNCTUS (Morton) (p. 83).

Acad. Nat. Sci. Philadelphia 1485, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Anterior surface of the test.
Posterior surface of the test.
Central portion of the petaloidal region of an ambulacral area, x 5.

. Basal portion of same, x 4.
2h.

Apical system, 5.
CaRDIASTER SMOCKI Clark (p. 84).
Geol. Survey New Jersey, type.
Upper surface of the test.

Lower surface of the test.
Lateral surface of the test.

MONOGRAPH LIV PLATE XXXVII

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

PLATE XXXVII.

CaRDIASTER CuRTUS Clark, n. sp. (p. 84).

U.S. Nat. Mus. 31201, type.

Figure la. Upper surface of the test.

1b. Lower surtace of the test.

1c. Lateral surface of the test.

1d. Apical system, x 10.

le. Portion of ambulacrum, 10.

1f. Several plates of same, X 15.

1g. Portion of interambulacrum, 10.

lh. Interambulacral plate, 15.

266

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXXVIII

osu pS
PERE

Ta aa a:

CRETACEOUS ECHINOIDEA.

PLATE XXXVIII.

HOo.asterR sIMPLEX Shumard (p. 85).

U.S. Nat. Mus. 8382, figured specimen A.

Fiaure la. Lateral surface of the test.
1b. Lateral surface of the test restored.
le. Posterior surface of the test.
1d. Portion of the ambulacrum, «
le. Portion of the ambulacrum, <
lf. Tubercle, x 10.
lg. Tubercle, x 10.
1h. Interambulacral plate, x 3.
li. Right anterolateral ambulacrum, X 2.
1j. Apical system, X 3.

3.
3.

=

267

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XXXIX

<

\
vet
TST LL

le

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

la

Ib.
le.
1d.
le.

lf.

lg.

PLATE XXXIX.

HOLaAsteR sIMPLEX Shumard (p. 85).

Geol. Survey Texas, figured specimen B.

. Upper surface of the test.

Lower surface of the test.

Lateral surface of the test.
Anterior surface of the test.

Apical system, X 4.

Portion of ambulacrum, x 10.
Three interambulacral plates, 5.

ENALLASTER TEXANUS (Roemer) (p. 86).

U.S. Nat. Mus. 9857.
. Upper view of the test.
. Lower view of the test.
. Posterior view of the test.
. Posterior view of the test.
. Portion of the petaloidal region of the right anterolateral ambulacrum, < 10.
. Portion of the anterior ambulacrum, x 10.
. Apical system, < 6.
268

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XL

CRETACEOUS ECHINOIDEA.

Figur la

1b.
IG,
Id.
le.

PLATE Xa:

ENALLASTER OBLIQUATUS Clark (p. 87).

U.S. Nat. Mus. 12237, type.
. Upper surface of the test.
Lower surface of the test.
Lateral view of the test.
Posterior view of the test.
Portion of the petaloidal region of the anterior ambulacrum, X 8.
Same, left anterior ambulacrum, 8.
. Second plate of the same from the mouth opening, x 8.
. Diagram showing arrangement of plates about the mouth opening, X 3.
Apical system, < 6.
. Tubercle from above, & 10.

. Lateral view of the same, 10.

269
29800 eh — ll

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLI

Uh Cn fel
Lis oa:
x Mi

Bz

AL

CRETACEOUS ECHINOIDEA.

PLATE Xai.

HEMIASTER ELEGANS Shumard (p. 88).

U.S. Nat. Mus. 21887.

Ficure la. Upper surface of the test.
lb. Lateral surface of the test.
1c. Posterior surface of the test.

270

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLII

CRETACEOUS ECHINOIDEA.

Figure la.
lb.
le,
1d.
le.

Ib

th.

lg.

PEATH XC:

T[EMIASTER ELEGANS Shumard (p. 88).

Geol. Survey Texas.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Apical system, 5.
Portion of anterior ambulacrum, X 5.
Same.
Portion of interambulacrum, 5.

271

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLIII

i >, \
ml

8 BOUL OOSS SS
ie ao Qoa oo
of DOG ONG
ool 8AM M0aag
900000
90 on0,

°
°
‘0
°

one
poe 22199°%8 G06

foo 4000707 002040ag
pee Gees f9 O090090K4 Son
ef so ‘
; 000000 °
acl MOON Gq en 990

CRETACEOUS ECHINOIDEA.

Figure la.
lb.
ies
ld.
le.
iit:

Ficure 2a.

2b

2c

PLATE Xai:

HEMIASTER ELEGANS Shumard (p. 88).

U.S. Nat. Mus. 21887.
Lower portion of the test.
Middle portion of the petaloidal region of the anterior ambulacrum, X 9.
Same, left anterolateral ambulacrum, x 5.
Two interambulacral plates, 3.
Apical system, < 5.
Upper portion of the anterior ambulacrum, 3.

Tlemraster wutrer Clark (p. 89).

U.S. Nat. Mus. 9732 type.

Upper surface of the test.
. Posterior surface of the test.

. Lateral surface of the test.

272

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLIV

W \"
~

\\
\S

CRETACEOUS ECHINOIDEA.

PLATE XLIV.

HemMrasterR WHITE! Clark (p. 89).

U.S. Nat. Mus. 9732, type.
Ficure la. Lower surface of the test.
1b. Right anterolateral interambulacrum, 3.
le. Lower portion of the petaloidal region of the right anterolateral ambulacrum, 8.
1d. Several plates of the petaloidal region of the left anterolateral ambulacrum, x 8.
le. Peristomial opening, with surrounding ambulacral and interambulacral plates, < 3.
lf. Apical system, x 5.
1g. Left anterolateral ambulacrum, 3.
lh. Diagram showing the arrangement of the plates in the apical system and bordering areas, X 3.

273

U. S. GEOLOGICAL SURVEY

MONOGRAPH LIV PLATE XLV

CRETACEOUS ECHINOIDEA.

PLATE XLV.

HEMIASTER WHITEI Clark (p. 89).

U.S. Nat. Mus. 31202.
Ficure la. Upper surface of the test.
lb. Lateral surface of the test.
lc. Posterior surface of the test.

HEMIASTER WHITEI Clark (p. 89).

U.S. Nat. Mus. 4544.

Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
2e. Apical system, 5.
2f. Portion of ambulacrum, X 8.
274

MONOGRAPH LIV PLATE XLVI

U. S. GEOLOGICAL SURVEY

CRETACEOUS ECHINOIDEA.

FIGuRE la.
1b.
ilies
ld.
le.

FIGURE 2a.
2b.
PAO
2d.

PLATE XLVI.

HIEMIASTER BEXARI Clark, n. sp. (p. 89).

U.S. Nat. Mus. 8330, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Portion of ambulacrum, & 5.

HEMIASTER COMANCHE! Clark, n. sp. (p. 90).

Johns Hopkins Univ. T 3012, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

215

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLVII

CRETACEOUS ECHINOIDEA.

FIGURE

FIGURE

la.
Ib.
le.
ld.
le.

iby,

fom)

ia)

ppb wb bw wp
oe fe)

bo bo
> S09

PLATE XLVII.

HEeMIASTER DALLI Clark (p. 90).

U.S. Nat. Mus. 19114, type.
Upper surface of the test.
Upper surface of the test restored.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Several plates from the petaloidal portion of the left anterolateral ambulacrum, x 5.

HEMIASTER CALVINI Clark (p. 90).

U.S. Nat. Mus. 12241, type.

. Upper surface of the test.

. Lower surface of the test.

. Lateral view of the test.

. Posterior view of the test.

. Several plates from the petaloidal region of the right posterolateral ambulacrum, X 5.

Same, lower portion of petaloidal region, X 5.

. Several plates from anterior ambulacrum, X 5.
. Interambulacral plate, 3.
. Apical system, x 5.

276

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLVIII

CRETACEOUS ECHINOIDEA.

PLATE XLVIII.

HeEMIAsTER PARASTATUS (Morton) (p. 92).
Acad. Nat. Sci. Philadelphia 1487, type.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Lateral surface of the test.
1d. Posterior surface of the test.
le. Anterior ambulacrum, 2.
lf. Portion of petaloidal region of the same, X 8.
lg. Portion of basal region, ditto, x 5.
lh. Several plates from the petaloidal region of the right anterolateral ambulacrum, x 5.
li. Three interambulacral plates, with fasciole, 3.
1k. Portion of fasciole, x 10.
ll. Tubercle from the side, « 20.
1m. Same from above, X 20.
In. Apical system, X 5.

HEMIASTER STELLA (Morton) (p. 93).

U.S. Nat. Mus. 2208.
Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.

HeEMIASTER UNGULA (Morton) (p. 93).
Acad. Nat. Sci. Philadelphia 1503, type.

FiagureE 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.
3e. Portion of the petaloidal region of the right anterolateral ambulacrum, X 8.
3f. Same, anterior ambulacrum, X 8.
3g. Apical system, * 5.
39800°—15 22 277

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XLIX

CRETACEOUS ECHINOIDEA.

PLATE XLIX.

HEMIASTER TEXANUS Roemer (p. 94).

Johns Hopkins Univ. T 3013.

Ficure la. Upper surface of the test.

1b. Lower surface of the test restored, 14.

lc. Lower surface of the test, ditto, x 14.

1d. Lateral surface of the test, x 14.

le. Posterior surface of the test, ditto, 14.

lf. Several plates from the petaloidal region of the right posterolateral ambulacrum, 8.

lg. Same, anterior ambulacrum, X 8.

th. Apical system, X 5.

li. Lateral view of a tubercle, < 20.

1j. Tubercle from above, * 20.

H[EMIASTER HUMPHREYSANUS Meek and Hayden (p. 95).

U.S. Nat. Mus. 331, type.
Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
2e. Several plates from the petaloidal portion of the left anterolateral ambulacrum, x 8.
2f. Several plates from the petaloidal portion of the anterior ambulacrum, X 8.

278

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE L

CRETACEOUS ECHINOIDEA.

Figure la.
Ib.
Ue;
1d.

FIGURE 2a.
2b.
2c.

Figure 3a.
3b.
3c.
3d.

PLATE: 1.
HEMIASTER CALIFORNICUS Clark (p. 96).
U.S. Nat. Mus. 31203, type.
Upper surface of the test.
Upper surface of the test, restored.

Lower surface of the test.
Lateral surface of the test.

H®MIASTER BEECHERI Clark, n. sp. (p. 96).
Peabody Museum, Yale University, 1863, type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

HeMIASTER LACUNOSUS Slocum (p. 97).

U.S. Nat. Mus. 31204, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LI

CRETACEOUS ECHINOIDEA.

PLATE LI.

HEMIASTER LACUNOSUS Slocum (p. 97).

Field Mus. P 10342, type.

Ficure la. Upper surface of the test.

1b. Lower surface of the test.

1c. Lateral surface of the test.

1d. Posterior surface of the test.

le. Apical system, X< 10.

1f. Portion of anterior ambulacrum, 8.

lg. Same, petaloidal region, X 8.

th. Lateral view of tubercle, X 20.

li. Tubercle from above, X 20.

280

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LII

CRETACEOUS ECHINOIDEA.

PLATE LII.
HEMIASTER KUMMELLI Clark (p. 97).

Geol. Survey New Jersey, type.
Ficure la. Upper surface of the test.
lb. Lower surface of the test.
lc. Lateral surface of the test.

TleMIASTER WELLERI Clark (p. 98).

Geol. Survey New Jersey, type.
Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

U. S. GEOLOGICAL SURVEY

MONOGRAPH LIV PLATE LIIl

CRETACEOUS ECHINOIDEA.

PLATE LIII.
LINTHIA TUMIDULA Clark (p. 99).

Am. Mus. Nat. Hist., type.
Ficure la. Upper surface of the test.
lb. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.
le. Upper portion of the anterior ambulacrum, X 5.
li. Several plates from the petaloidal region of the left posterolateral ambulacrum, X 8,
lg. Apical system, X 5.
th. Tubercle from the side, 20.
li. Tubercle from above, X 20.

282

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LIV

CRETACEOUS ECHINOIDEA.

Fiaure la.

Ib.

le.

1d.

le.
lf.

lg.

th.

hi.

1k.

ll.

PEAGH GV:

LINTHIA VARIABILIS Slocum (p. 99).

Field Mus. P 10457, type.

Upper surface of the test (P 10457).
Lower surface of the test (P 10457).
Lateral surface of the test (P 10457).
Posterior surface of the test (P 10457).
Upper surface of the test (P 10457).
Lower surface of the test (P 10457).
Lateral surface of the test (P 10457).
Posterior surface of the test (P 10457).
Apical system, X 10.

Portion of ambulacrum, 20.
Portion of ambulacrum, X 8.

283

MONOGRAPH LIV PLATE LV

U. S. GEOLOGICAL SURVEY

EOCENE ECHINOIDEA.

PLATE LV.

CIDARIS MITCHELLI Emmons (p. 113).
Williams College, type.

Ficure la. Upper surface of the test.
lb. Lower surface of the test.
lc. Lateral surface of the test.

CIDARIS CAROLINENSIS Emmons (p. 113).

Williams Coliege, type.
Fictre 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

Ciparis PRATTI Clark, n. sp. (p. 114).
U.S. Nat. Mus. 164663, type.
Fieure 3. Portion of interambulacrum with adjoining ambulacra.

Criparts MeRRIAMI Arnold (p. 114).

U.S. Nat. Mus. 165438, type.
Fiaure 4. Spine, after Arnold.
284

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LVI

EOCENE ECHINOIDEA.

Figure la.
lb.
icy
ld.
le.

li.

th.

ae

Figure 2a.
2b.

le.

Jeb Mo, TEAL

C@LOPLEURUS INFULATUS (Morton) (p. 117).
Acad. Nat. Sci. Philadelphia 1076.

Upper surface of the test, & 2.

Lateral surface of the test, « 2.

Lower suriace of the test, « 2.

Upper portion of an ambulacrum, X 6.

Four compound plates of an ambulacrum, X 6.
Three plates of an interambulacrum, x 6.

An interambulacrum, 6.

Tubercle, « 10.

Apical system, x 4.

ORTHECHINUS PRETIOSUS Clark, n. sp. (p. 118).

U.S. Nat. Mus. 146455, type.
Upper surface of the test.
Lateral surface of the test.

Ecurnus (7?) sp. (p. 118).
Johns Hopkins Univ. T 2000.

Figure 3. Spines.

39800°—15

iW)
Nn
ot

23

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LVII

EOCENE ECHINOIDEA.

PLATE LVII.

ECHINOCYAMUS HUXLEYANUS Meyer (p. 119).

Johns Hopkins Univ. T 2006.
Figure la. Upper surface of the test, 4.
1b. Lower surface of the test, * 4.
le. Lateral surface of the test, x 4.
1d. Posterior surface of the test, « 4.

oN

EcurnocyaMus TEXANUS Twitchell, n. sp. (p. 120).

Johns Hopkins Univ. T 2002, type.
Figure 2 2
2b. Lower surface of the test, x 2.
2c. Lateral surface of the test, * 2.
2d. Posterior surface of the test, * 2.

FIBULARIA MERIDIONALIS (Meyer) (p. 121).

Johns Hopkins Univ. T 2005.

Fieure 3a. Upper surface of the test, x 44.
3b. Lower surface of the test, 44.
3c. Lateral surface of the test, « 44.
3d.. Posterior surface of the test.

SisMONDIA (¢) PLANA Conrad (p. 121).

Acad. Nat. Sci. Philadelphia 1080, type.
Figure 4a. Upper surface of the test.
4b. Lower surface of the test.
4c. Lateral surface of the test.
4d. Posterior surface of the test.

Lacanum (?) crusTULoIpEs (Morton) (p. 122).

Boston Soc. Nat. Hist. 8802a, specimen A.

Ficure 5a. Upper suriace of the test.
5b. Lower surface of the test.
5c. Lateral surface of the test.
5d. Posterior surface of the test.

LaGcanum (?) crustuLorpEs (Morton) (p. 122).

U.S. Nat. Mus. 164744, specimen B.

Ficure 6a. Upper surface of the test.
6b. Lower surface of the test.
6c. Lateral surface of the test.
Gd. Posterior surface of the test.

286

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LVIII

EOCENE ECHINOIDEA.

PLATE LVIII.

Prriarcuus ALTUS Conrad (p. 130).

Williams College, type.
FicureE la. Upper surface of the test.
lb. Lower surface of the test.
le. Detail of apical system, 5.
1d. Posterior surface of the test.
le. Lateral surface of the test.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LIX

EOCENE ECHINOIDEA.

PLATE LIX.

SCUTELLA MISSISSIPPIENSIS Twitchell, n. sp. (p. 124).
U.S. Nat. Mus. 137655, specimen A, type.

Fiaure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Posterior surface of the test.
1d. Lateral surface of the test.
le. Apical system, X 6.
lf. Part of the ambulacra, x 8.

ScUTELLA MISSISSIPPIENSIS Twitchell, n. sp. (p. 124).

U.S. Nat. Mus. 137655a, specimen B.
Figure 2. Upper surface of the test.
288

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LX

EOCENE ECHINOIDEA.

FIGuRE la.
Ib.
le.
ld.

FIGureE 2a.
2b.
2c.
2d.
2e.

2

ai.

PLATE LX.
ScurELLA TUOMEYI Twitchell, n. sp. (p. 125).

U.S. Nat. Mus. 137970, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

MorTONELLA QUINQUEFARIA (Say) (p. 128).

U.S. Nat. Mus. 9500, specimen A.

Upper surface of the test.

Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.

Part of one of the ambulacra, x 4.
Apical system, X 6.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXI

i

Mola

EOCENE ECHINOIDEA.

PLATE LXI.

MOoORTONELLA QUINQUEFARIA (Say) (p. 128)

Amherst College, specimen B.
Ficure la. Upper surface of the test.
lb. Lateral surface of the test.

PERIARCHUS LYELLI Conrad (p. 131).
Boston Soc. Nat. Hist. 1553, specimen A.

Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
2e. Part of one of the ambulacra, x 5}.
2f. Apical system, x 4.

290

U. S. GEOLOGICAL SURVEY

EOCENE ECHINOIDEA.

MONOGRAPH LIV PLATE LXiII

FIGURE

FIGURE

FIGURE

la.
lb.
le.

2a.
2b.
ZC
2d.

3a.
3b.
3Ce
3d.
8e.

3f.

PLATE LXII.

PERIARCHUS LYELLI Conrad (p. 131).
Johns Hopkins Univ. T 2003, specimen B.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

PERIARCHUS LYELLI Conrad (p. 131).
Johns Hopkins Uniy. T 2004, specimen C.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

PERIARCHUS PROTUBERANS Twitchell, n. sp. (p. 133).

U.S. Nat. Mus. 164685, type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Part of one ambulacrum, X 8.
Apical system, X 8.
291

MONOGRAPH LIV PLATE LXIIl

U. S. GEOLOGICAL SURVEY

EOCENE ECHINOIDEA.

PLATE LXIII.

PERIARCHUS PILEUS-SINENSIS Ravenel (p. 135).
U.S. Nat. Mus. 5133, specimen A.

Figure la. Upper surface of the test.
lb. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.
le. Part of one ambulacrum, X 6.

PERIARCHUS PILEUS-SINENSIS Ravenel (p. 135).

U.S. Nat. Mus. 137791, specimen B.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Posterior surface of the test.
2d. Lateral surface of the test.

292

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXIV

EOCENE ECHINOIDEA.

PLATE LXIV.

ScuTeLia(?) conrapt (Cotteau) (p. 126).
Acad. Nat. Sci. Philadelphia 1081, type.

Figure la. Upper surface of the test.
lb. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.

CLYPEASTER ROGERSI Morton (p. 136).
U.S. Nat. Mus. 137801, specimen A.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Posterior surface of the the test.
2d. Lateral surface of the test.

CLYPEASTER ROGERSI Morton (p. 136).
U.S. Nat. Mus. 155377, specimen B.

Ficure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.

39800°—15 24 293

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXv

EOCENE ECHINOIDEA.

Ficure la.
lb.
le.
ld.

FIGURE 2a.
. Lower surface of the test.

FIGURE 3a.
3b.
3.
3d.

FIGURE 4a.
Ab.
4c.
4d.

FIGURE 5a.
5b.
5c.
5d.

PLATE LXV.

ECHINANTHUS GEORGIENSIS Twitchell, n. sp. (p. 139).

U.S. Nat. Mus. 165683b, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

CASSIDULUS CALIFORNICUS F’. M. Anderson (p. 140).

U.S. Nat. Mus. 165664.
Upper surface of the test.

CassipuLus (RuyNncuopycGus ?) Ho“MEsr Twitchell, n. sp. (p. 140).

Am. Mus. Nat. Hist., type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

CassrpuLus (RuyNCHOPYGUS) LYELLI (Conrad) (p. 141).

Boston Soc. Nat. Hist. 1552a.
Upper surface of the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.

CassrpuLUs (RHYNCHOPYGUS) RAVENELI Twitchell, n. sp. (p. 142).

Am. Mus. Nat. Hist., specimen A, type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

294

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXVI

EOCENE ECHINOIDEA.

Ficure la.
lb.
N@z

FIGuRE Za.
2b.

FIGURE 3a.
3b.
3:
3d.

Figure 4a.
4b.
4c.
4d.
4e.

FIGURE 5a.
5b.

PLATE LXVI.

CassipuLUS (RHYNCHOPYGUS) RAVENELI Twitchell, n. sp. (p. 142).

Am. Mus. Nat. Hist., specimen B.
Upper surface of the test.
Part of one ambulacrum, X 8.
Apical system, X 8.

CassipuLuS (RHYNCHOPYGUS) RAVENELI Twitchell, n. sp. (p. 142).

Am. Mus. Nat. Hist., specimen C.
Lower surface of the test.
Part of floscelle, x 4.
CassipuLus (RiyNCHOPYGUS ?) PATELLIFORMIS (Bouvé) (p. 143).

Boston Soc. Nat. Hist. 1558, type.

Upper surface of the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.

CassripuLus (RuyNCHOPYGUS) DEPRESSUS Twitchell, n. sp. (p. 144).

Boston Soc. Nat. Hist. 1557a, specimen A, type.

Upper surface of the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.

Part of one ambulacrum, X 12.

CassipuLUS (RHYNCHOPYGUS) DEPREsSUS Twitchell, n. sp. (p. 144).
Boston Soc. Nat. Hist. 1557b, specimen B.

Lower surface of the test.
Part of floscelle, x 8.
295

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXVII

EOCENE ECHINOIDEA.

FIGURE

FIGURE

la

1b.
ie?
ld.
le.

i.

2a.

PLATE LXVII.

CasstDULus (PyGoRHYNCHUS) CONRADI Conrad (p. 145).
Acad. Nat. Sci. Philadelphia 1078, probably type.

. Upper surface of the test.
Lower surface of the test.
Posterior suriace of the test.
Lateral surface of the test.
Part of one ambulacrum, X 8.
Part of floscelle, X 7.

CassipULUS (PYGORHYNCEUS) CAROLINENSIS Twitchell, n. sp. (p. 146).

Johns Hopkins Uniy. T 2004, type.

Upper surface of the test.
. Lower surface of the test.
. Lateral suriace of the test.
. Posterior surface of the test.
. Part of floscelle, 5.

Part of one ambulacrum, X 84.
. Apical system, X 6.
296

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXVIII

EOCENE ECHINOIDEA.

FIGURE

FIGURE

la

Ib.
ies
ld.
lex

if.

2a.
2b.
2c.
2d.
2e.

2f.

oe

a.

2h:

PLATE LXVIII.

BREYNELLA GREGORYI Twitchell, n. sp. (p. 148).
Am. Mus. Nat. Hist., type.

. Upper surface oi the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.
Apical system, X 6.

Part of ambulacra.

ECHINOLAMPAS APPENDICULATUS Emmons (p. 149).

U.S. Nat. Mus. 138017.
Upper surface of the test.
Lower surface of the test.
Posterior surface of the test.
Lateral surface of the test.
Part of floscelle, X 4.
Apical system, X 5.
Part of interambulacra.
Part of ambulacra, < 10.

297

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXIX

EOCENE ECHINOIDEA.

FIGURE la.
1b.
Ike,
ld.

FIGURE 2a.
2b.

FIGURE 3a
3b

PLATE LXIX.

HeEMIPATAGUS ARGUTUS Clark, n. sp. (p. 150).

U.S. Nat. Mus. 141107, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

HEMIPATAGUS SUBROSTRATUS Clark, n. sp. (p. 151).

U.S. Nat. Mus. 164652, type.
Upper surface of the test.
Anterior surface of the test.

SCHIZASTER LECONTEL Merriam (p. 151).

Univ. of California, type.
. Upper surface of the test.
. Lower surface of the test.
298

MONOGRAPH LIV PLATE LXX

U. S. GEOLOGICAL SURVEY

EOCENE ECHINOIDEA.

PLATE LXX.

SCHIZASTER ARMIGER Clark, n. sp. (p. 152).

U.S. Nat. Mus. 141104, type.
Figure la. Upper surface of the test.
lb. Lower surface of the test.
lc. Lateral surface of the test.
1d. Posterior surface of the test.

SCHIZASTER sp. (p. 152).

Johns Hopkins Univ. T 2001.

Ficure 2. Fragment of the test showing portion of ambulacrum with adjacent interambulacrum.

LINTHIA WILMINGTONENSIS Clark, n. sp. (p. 152).

U.S. Nat. Mus. 166482, type.
Ficure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.

bo

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXxX!

EOCENE ECHINOIDEA.

PLATE LXXI.

LINTHIA ALABAMENSIS Clark, n. sp. (p. 153).

U.S. Nat. Mus. 173371, type.
Ficure la. Upper surface of the test.
lb. Lower surface of the test.
1c. Lateral surface of the test.
ld. Posterior surface of the test

LINTHIA ALABAMENSIS Clark, n. sp. (p. 158).

U.S. Nat. Mus. 166483.
Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.

EUPATAGUS CAROLINENSIS Clark, n. sp. (p. 158).

U.S. Nat. Mus. 166484, type.
Figure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.

EUPATAGUS CAROLINENSIS Clark, n. sp. (p. 153).

U.S. Nat. Mus. 164674.
Ticure 4. Upper surface of the test.

MAcROPNEUSTES CAROLINENSIS Clark, n. sp. (p. 154).

U.S. Nat. Mus. 164651, type.
I'rcure 5a. Upper surface of the test.
5b. Lower surface of the test.
5c. Lateral surface of the test.
5d. Posterior surface of the test.

300

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXxXil

EOCENE ECHINOIDEA.

Ficure la.
Ib.
ie?
ld.

FIGureE 2a.
2b.
2c.
2d.

39800°—15,

PLATE LXXII.

MACROPNEUSTES MORTONI (Conrad) (p. 155).

U.S. Nat. Mus. 146468.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

SARSELLA GREGORY! Clark, n. sp. (p. 155).

Am. Mus. Nat. Hist., type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

25

301

MONOGRAPH LIV PLATE LXXiIll

U. S. GEOLOGICAL SURVEY

OLIGOCENE ECHINOIDEA.

PLATE LXXIII.

Crparis MORTONI Conrad (p. 157).

Boston Soc. Nat. Hist. 1555.
Fiaure 1. Portion of test.
Ciparis smrrat Clark, n. sp. (p. 157).

Alabama Geol. Survey, type.
Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

Crparis smiTuHt Clark, n. sp. (p. 157).

Alabama Geol. Survey.

Ficure 3. Spine.
CIpARIS GEORGIANA Clark, n. sp. (p. 158).

U.S. Nat. Mus. 166485, type.
Ficure 4. Portion of the test.

Crmaris BRANNERI Arnold (p. 158).

Leland Stanford Junior Univ. 1056, type.
Ficure 5. Spine.
CaLOPLEURUS ALDRICHI Clark, n. sp. (p. 158)

J. S. Nat. Mus. (Aldrich), type.

Ficure 6a. Upper surface of the test.
6b. Lateral surface of the test.

Ca@LOPLEURUS ALDRICHI Clark, n. sp. (p. 158).

U.S. Nat. Mus. ( Aldrich).

Figure 7a. Upper surface of the test.
7b. Lower surface of the test.
7c. Lateral surface of the test.

GAGARIA AMERICANA Clark, n. sp. (p. 159).

U.S. Nat. Mus. (Aldrich), type.

Ficure 8a. Upper surface of the test.
8b. Lateral surface of the test.

302

MONOGRAPH LIV PLATE LXXIV

U. S. GEOLOGICAL SURVEY

OLIGOCENE ECHINOIDEA.

PLATH LXXIV.
EcHINOCYAMUS VAUGHAN Twitchell, n. sp. (p. 160).

; U.S. Nat. Mus. 166486, type.
Ficure la. Upper surface of the test, X 2.
1b. Lower surface of the test, & 2.
le. Lateral surface of the test, X 2.
1d. Posterior surface of the test, 2.

LaGANuM ELDRIDGE! Twitchell, n. sp. (p. 160).

U.S. Nat. Mus. 164683, type.
Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior of the test.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXV

OLIGOCENE ECHINOIDEA.

Ficure la.
Ib.

le.

Id.

Figure 2a.
2b.
2e%

2d.

FIGURE 3a.
3b.
8c.
3d.

Figure 4a.
4b.
Ac.
4d.

PLATE LXXyV.
LAGANUM ARCHERENSIS Twitchell, n. sp. (p. 161).

U.S. Nat. Mus. 164667a, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

LaGanum jounsont Twitchell, n. sp. (p. 162).

U.S. Nat. Mus. 137202, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

LaGanuMm FLoripaANnuM Twitchell, n. sp. (p. 163)

U.S. Nat. Mus. 137884, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

LaGanum pair Twitchell, n. sp. (p. 164).

U.S. Nat. Mus. 164667b, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

304

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXVI

OLIGOCENE ECHINOIDEA.

Ficure la
1b

AMBLYPYGUS MERRILLI Twitchell, n. sp. (p. 165).

. Upper surface of the test.
. Lower surface of the test.

PLATE LXXVI.

U.S. Nat. Mus. 164934, specimen A, type.

Ic. Part of one ambulacrum, X 3

1d

. Apical system, X 3.

305

MONOGRAPH LIV PLATE LXXVII

U. S. GEOLOGICAL SURVEY

OLIGOCENE ECHINOIDEA

PLATE LXXVII.
AMBLYPYGUS MERRILLI Twitchell, n. sp. (p. 165).
U.S. Nat. Mus. 164934, specimen A.

Ficure la. Lateral surface of the test.
1b. Posterior surface of the test.

AMBLYPYGUS MERRILLI Twitchell, n. sp. (p. 165).
U.S. Nat. Mus. 137870, specimen B,

Ficure 2a. Upper surface of the test
2b. Lower surface of the test.
306

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXVIII

OLIGOCENE ECHINOIDEA.

Figure la.
1b.

FIGURE

FIGURE

FIGURE

FIGURE

2a.
2b.
2c.
2d.

3a.
3b.

4a.
4b.

A

5a.

5b.

5e.
5d.

Cs
4d.

PLATE LXXVIII.

AMBLYPYGUS MERRILLI Twitchell, n. sp. (p. 165).

U.S. Nat. Mus. 137870, specimen B.

Lateral surface of the test.
Posterior surface of the test.

OLIGopyGus WETHERBY! De Loriol (p. 166).

U.S. Nat. Mus. 13788la, specimen A.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

OLIGoPYGUS WETHERBYI De Loriol (p. 166).

U.S. Nat. Mus. 137881b, specimen B.

Part of one ambulacrum, X 8.
Apical system, 5.

OLIGOPYGUS HALDERMANI (Conrad) (p. 167).
I

U.S. Nat. Mus. 112506, specimen A.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

OLIGOPYGUS HALDERMANI (Conrad) (p. 167).

U.S. Nat. Mus. 164661, specimen B.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

07

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXIxX

OLIGOCENE ECHINOIDEA.

FIGURE

FIGURE

FIGURE

la.
lb.
le.
1d.
Hey

If.

2a:
2b.
2c.

2d.

3a.
3b.
3c.
3d.

PLATE LXXIX.

OLIGOPYGUS FLORIDANUS Twitchell, n. sp. (p. 169).

U.S. Nat. Mus. 164660, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Apical system, x 44.
Part of one ambulacrum, * 10.

CASSIDULUS (PYGORHYNCHUS) GEORGIENSIS Twitchell, n. sp. (p. 170).

U.S. Nat. Mus. 164347, type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test. -

CassipuLus (PyGorHyNcuHuts) GouLpi (Bouyé) (p. 171).

Boston Soc. Nat. Hist. 1756, specimen A, type.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

308

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXX

AIT oe ee
19) NY yy, A

yy,
Yppiy,
Mii),

OLIGOCENE ECHINOIDEA.

FIGURE

FIGURE

FIGURE

la.
Ib.
ek
ld.

le
If.

2a.
2b.
2c.
2d.

3b.

9

3c.
3d.
39800°—15

PLATE LXXX.

CasstpuLus (PyGoRHYNCHUs) GOULDIL (Bouvé) (p. 171).
U.S. Nat. Mus. 137904, specimen B.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.
Part of floscelle, X 5.

Part of one ambulacrum, X 54.

CassipuLus (PYGORHYNCHUs) GoULDI (Bouvé) (p. 171).

U.S. Nat. Mus. 137904a, specimen C.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

CAssrpULUs (PYGORHYNCHUS) ALABAMENSIS Twitchell, n. sp. (p. 172).

Johns Hopkins Univ., type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

26

309

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXxXI

OLIGOCENE ECHINOIDEA.

PLATE LXXXI.

ECHINOLAMPAS ALDRICHI Twitchell, n. sp. (p. 173).

Johns Hopkins Univ. T 1099, specimen A, type.

Figure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Lateral surface of the test.
1d. Posterior surface of the test.

ECHINOLAMPAS ALDRICHI Twitchell, n. sp. (p. 173).

Johns Hopkins Uniy. T 1099.
Fieure 2. Part of floscelle, X 44.

AGassIzIA CoNRADI (Bouvé) (p. 174).

U.S. Nat. Mus. 164744.
Figure 3a. Upper surface of the test.

3b. Lower surface of the test.

3c. Lateral surface of the test.

3d. Posterior surface of the test.
310

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXxXIl

Solis ire |

OLIGOCENE ECHINOIDEA.

FIGURE la.
1b.
le.

Figure 2a.
2b.
2c.
2d.

FIGURE 3a.
3b.
3c.
3d.

SCHIZASTER FLORIDANUS Clark, n. sp. (p. 175).

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

Eupatacus FLORIDANUS Clark, n. sp. (p. 176).

Upper surface of the test.
Lower suriace of the test.
Lateral surface of the test.

Posterior suriace of the test.

SCHIZASTER AMERICANA Clark, n. sp. (p. 176).

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Anterior suriace of the test.

PLATE LXXXII.

U.S. Nat. Mus. 164655, type.

U.S. Nat. Mus. 137881, type.

U.S. Nat. Mus. 165695, type.

311

MONOGRAPH LIV PLATE LXXxXIlI

U. S. GEOLOGICAL SURVEY

OLIGOCENE ECHINOIDEA.

PLATE LXXXIII.

EUPATAGUS FLORIDANUS Clark, n. sp. (p. 176).

Wagner Free Inst. Sci., specimen B.

Figure la. Upper surface of the test.
1b. Lower surface of the test.
1c. Lateral surface of the test.

FEUPATAGUS FLORIDANUS Clark, n. sp. (p. 176).
Mus. Comp. Zool., specimen C.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.

312

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXXIV

MIOCENE STELLEROIDEA AND ECHINOIDEA.

PLATE LXXXIV.

OPHIODERMA (7%) sp. (p. 178).

Johns Hopkins Univ. T 1000.

Fiaure 1. Fragment of arms.

AMPHIURA SANCTCRUCIS Arnold (p. 178).

Stanford Univ. 1078, type.

Figure 2. Cast of dorsal surface, * 3.

FIGuRE 3.

FIGuReE 4a.
4b.
4c.

Figure 5a.
5b.

Ficgure 6a.
6b.
6c.

AMPHIURA sANCTAcRUCIS Arnold (p. 178).

U.S. Nat. Mus. 165431, type.

Cast of ventral surface.

C&LOPLEURUS IMPROCERUS (Conrad) (p. 180).

U.S. Nat. Mus. 166487.
Upper surface of the test.
Lower surface of the test.
Lateral suriace of the test.

C@LOPLEURUS SLOANT Clark, n. sp. (p. 181).

U.S. Nat. Mus. 166488, type.
Upper surface of the test.
Lateral surface of the test.

PSAMMECHINUS PHILANTHROPUS (Conrad) (p. 181).

Johns Hopkins Univ. T 1001.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

31

MONOGRAPH LIV PLATE LXXXV

S. GEOLOGICAL SURVEY

U.

MIOCENE ECHINOIDEA

PLATE LXXXyV.

SISMONDIA (7?) ARNOLDI Twitchell, n. sp. (p. 182).

U.S. Nat. Mus. 165538, type.
Figure la. Upper surface of the test, x 2.
lb. Lower surface of the test, x 2

SISMONDIA (?) COALINGAENSIS Twitchell, n. sp. (p. 183).

U.S. Nat. Mus. 165717, type.

Figure 2a. Upper surface of the test,
2b. Lower surface of the test,

2c. Lateral surface of the test, * 2.

lo bo

SCUTELLA ANDERSONI Twitchell, n. sp. (p. 183).

U.S. Nat. Mus. 165719, type.
Figure 3a. Upper surface of the test.
3b. Lower surface of the test.
3c. Lateral surface of the test.
3d. Posterior surface of the test.

SCUTELLA FAIRBANKsI Pack (p. 184).

Univ. California, specimen A, type.
Ficure 4. Upper surface of the test.

SCUTELLA FAIRBANKsI Pack (p. 184).
U.S. Nat. Mus. 164963. specimen B.
Ficure 5. Upper surface of the test.
SCUTELLA FAIRBANKS! Pack (p. 184).
U.S. Nat. Mus. 164963, specimen C.
Ficure 6. Upper surface of the test, 14.
ScurELLA (?) MERRIAMI (Anderson) (p. 185).
U.S. Nat. Mus. 165716, specimen A.

Ficure 7a. Upper surface of the test, x :
7b. Lower surface of the test,
7c. Lateral surface of the test.

bo bo

ScuTELLA (?) MERRIAMI (Anderson) (p. 185).

U.S. Nat. Mus. 165584, specimen B.

Z

Ficure 8a. Upper surface of the test, x
8b. Lower surface of the test,

bo

i)

ScuTELLA NorRIst Pack (p. 186).

Univ. California, type.
Ficure 9. Lower surface oi the test.
314

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXXVI

(ean

ant

MIOCENE ECHINOIDEA.

PLATE LXXXVI.
SCUTELLA ABERTI Conrad (p. 187).

Maryland Geol. Survey.
Ficure la. Upper surface of the test.
1b. Enlarged plate of the same species.
315

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXXVII

MIOCENE ECHINOIDEA.

PLATE LXXXVII.

ScuTELLA ABERTI Conrad (p. 187).

Maryland Geol. Survey.
FicurE la. Lower surface of the test.
lb. Lateral surface of the test.
le. Interambulacral plate.
1d. Another view of same.

316

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE LXXXVIII

MIOCENE ECHINOIDEA.

Figure la

Tb.

FIGurRE 2.

FIGURE 3a.
3b.
Xe

FIGURE 4a.
4b.
Ac.

4d

PLATE LXXXVIII.

ScuTELLA GABBI (Rémond) Merriam (p. 189).

Univ. California 19425.
. Upper surface of the test.
Lateral suriace of the test.

DENDRASTER PERRINI (Weaver) (p. 190).

U.S. Nat. Mus. 165560, specimen A.
Upper surface of the test.

DENDRASTER PERRINI (Weaver) (p. 190).

U.S. Nat. Mus. 165560, specimen B.

Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

DENDRASTER ARNOLDI Twitchell, n. sp. (p. 192).

U.S. Nat. Mus. 165707, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
. Posterior surface of the test.

39800°—15 74 6

317

MONOGRAPH LIV PLATE LXXXIX

U. S. GEOLOGICAL SURVEY

iy.

ie

Mina

MIOCENE ECHINOIDEA.

PG AME XOXeXT Xe

DENDRASTER GIBBSII (Rémond) (p. 193).

U.S. Nat. Mus. 165547, specimen A.

Ficure la. Upper surface of the test.
1b. Lateral surface of the test.

DENDRASTER GIBBsII (Rémond) (p. 193).

U.S. Nat. Mus. 165611, specimen B.
Ficure 2. Lower surface of the test.

DENDRASTER GIBBSIL (Rémond) (p. 193).

U.S. Nat. Mus. 165611, specimen ©.
Ficure 3. Upper surface of the test.

DENDRASTER GIBBsII (Rémond) (p. 193).

U.S. Nat. Mus. 165704, specimen D.
Ficure 4. Upper surface of the test.
318

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XC

MIOCENE ECHINOIDEA.

PLATE XC.

DENDRASTER OREGONENSIS (Clark) (p. 195).

U.S. Nat. Mus. 153975.
Fiaure 1. Upper surface of the test.

DENDRASTER COALINGAENSIS Twitchell, n. sp. (p. 196).

J.S Nat. Mus. 165537, type.
Ficure 2a. Upper surface of the test.
2b. Lower suriace of the test, 2.
2c. Lateral surface of the test, X 2

319

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCI

ii
\\

\ Nl

\
\

It

l

/}

Wim
y Hp
Hy

Soyer);

MIOCENE ECHINOIDEA. :

PLATE XCI.

MELLITA CAROLINIANA Ravenel (p. 204).

Acad. Nat. Sci. Philadelphia 1083.

Ficure la. Upper surface of the test.
1b. Lateral surface of the test.

320

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCII

MIOCENE ECHINOIDEA.

PLATE XCII.

MELLITA CAROLINIANA Ravenel (p. 204).

Acad. Nat. Sci. Philadelphia 1083.

Figure la. Lower surface of the test.
1b. Posterior surface of the test.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCIll

\

ny

UH

MIOCENE ECHINOIDEA.

PLATE XCIII.

ScUTASTER ANDERSONI Pack (p. 206).

Univ. California, type.
Ficure 1. Upper surface of the test.

ENcoOPE MACROPHORA Ravenel (p. 206).

Acad. Nat. Sci. Philadelphia 1086, specimen A.

Figure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.
2d. Posterior surface of the test.
2e. Apical system, X 34.

322

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCIV

aig
ri

1)
Ap
ie

‘h
Hy

MIOCENE ECHINOIDEA.

PLATE XCIV.

ENcoPE MACROPHORA Ravenel (p. 206).

U.S. Nat. Mus. 164658, specimen B.
Figure la. Upper surface of the test.
lb. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.
le. Part of one ambulacrum, & 8.
lf. Apical system, x 5.

Encore MacRopHoRA Ravenel (p. 206).

U.S. Nat. Mus. 9970, specimen C.
Ficure 2. Upper surface of the test.

ASTRODAPSIS ANTISELLI Conrad (p. 198).

U.S. Nat. Mus. 165466, specimen A.

Ficure 3. Upper surface of the test.
ASTRODAPSIS ANTISELLI Conrad (p. 198).

U.S. Nat. Mus. 165466a, specimen B.

Figure 4a. Lower surface of the test.
4b. Lateral surface of the test.

3

3

MONOGRAPH LIV. PLATE XCV

U. S. GEOLOGICAL SURVEY

NE ECHINOIDEA

MIOCE

Figure 1.

FIGURE 2a.
2b.
2c.

FIGURE 3a.
3b.

PLATE XCV.

ASTRODAPSIS ARNOLDI Twitchell, n. sp. (p. 199).

U.S. Nat. Mus. 165594, type.
Upper surface of the test.

ASTRODAPSIS WHITNEY! Rémond (p. 201).
Univ. California 19426.
Upper surface of the test.

Lower surface of the test.
Lateral surface of the test.

AsTRopapPsis TuUMIpUS Rémond (p. 202).
Univ. California 19424.

Upper surface of the test.
Lower surface of the test.

ASTRODAPSIS JACALITOSENSIS Arnold (p. 203).

U.S. Nat. Mus. 165610, type.

Ficure 4. Upper surface of the test.

Figure 5a.

5b.
5e.

5d.

CAsSIDULUS BASSLERI Twitchell, n. sp. (211).

U.S. Nat. Mus. 9476, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.
Posterior surface of the test.

824

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCVI

sex enget

Wy)

t
rng
foo,
if &

heroes

MIOCENE ECHINOIDEA.

PLATE XCVI.

CLYPEASTER BOWERSI Weaver (p. 209).

Univ. California, type.
Figure la. Upper surface of the test.
1b. Lower surface of the test.

CLYPEASTER (?) BREWERIANUS (Rémond) (p. 210).

Acad. Nat. Sci. Philadelphia 1088, specimen A.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

CLYPEASTER (?) BREWERTANUS (Rémond) (p. 210).

Univ. California 19423, specimen B.
Fiaure 3. Upper surface of the test.
39800°—15——28,

it)
bo
ot

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCVII

MIOCENE ECHINOIDEA.

PLATE XCVII.

AGASSIZIA PORIFERA (Ravenel) (p. 212).

Am. Mus. Nat. Hist.
Ficure la. Upper surface of the test.
lb. Lower surface of the test.
lc. Posterior surface of the test.
1d. Lateral surface of the test.

ECHINOCARDIUM ORTHONOTUM Conrad (p. 213).

Acad. Nat. Sci. Philadelphia 1079.

Ficure 2a. Upper surface of the test.
2b. Lower surface of the test.
2c. Lateral surface of the test.

326

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCVIII

MIOCENE ECHINOIDEA.

Figure la.
Ib.
le.

FIGURE 2a.
2b.

2c.

Figure 3a.
3b.
3c.

PLATE XCVIII.

ECHINOCARDIUM ORTHONOTUM Conrad (p. 214).

Am. Mus. Nat. Hist.
Upper surface of the test.
Lower surface of the test.
Anterior surface of the test.

ECHINOCARDIUM ORTHONOTUM Conrad (p. 214).

Johns Hopkins Univ. T 1002.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

EcHINOCARDIUM DEPRESSUM Clark, n. sp. (p. 214).

U. 8. Nat. Mus. 164454, type.
Upper surface of the test.
Lower surface of the test.
Lateral surface of the test.

Lintruia (?) CALIFORNICA Weaver (p. 214).

Univ. California, type.

Ticure 4. Upper surface of the test.

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE XCIX

PLIOCENE ECHINOIDEA.

PLATE XCIX.

STRONGYLOCENTROTUS DROBACHIENSIS (Miller) (p. 216).
Wagner Free Inst. Sci. 4350.

Figure la. Upper surface of the test.
1b. Lower surface of the test.
lc. Lateral surface of the test.

DIPLOTHECANTHUS DALLI Twitchell, n. sp. (p. 218).

U.S. Nat. Mus. 164670.

Ficure 2a. Posterior surface of the test.
2b. Lateral surface of the test.

328

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CG

PLIOCENE ECHINOIDEA.

PLATE C.

DrPLOTHECANTHUS DALLI Twitchell, n. sp. (p. 218).

U.S. Nat. Mus. 164670, type.
Ficgure la. Upper surface of the test.
1b. Lower surface of the test.

DENDRASTER INTERLINEATUS (Stimpson) (p. 216).

Univ. California 19427.
Fiaure 2a. Upper surface of the test.
2b. Lower surface of the test.
329

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE Cl

PLIOCENE ECHINOIDEA.

PLATE CI.

ASTRODAPSIS FERNANDOENSIS Pack (p. 217).

Univ. California, specimen A.
Fiacure 1. Upper surface of the test.

ASTRODAPSIS FERNANDOENSIS Pack (p. 217).

Univ. California, specimen B.
Ficure 2. Lower surface of the test.

CasstmpULUS BERRYI Twitchell, n. sp. (p. 220).

Johns Hopkins Univ. T 1, type.
F'1guRE 3a. Upper surface of the test.

3b. Lower surface of the test.

3c. Lateral surface of the test.

3d. Posterior surface of the test.
330

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE Cll

PLIOCENE ECHINOIDEA.

PLATE CII.

DIPLOTHECANTHUS ROSACEUS (Lamarck) (p. 219).

U.S. Nat. Mus. 165693.
Ficure la. Upper surface of the test.
1b. Lateral surface of the test.
33L

MONOGRAPH LIV PLATE Clll

U. S. GEOLOGICAL SURVEY

PLIOCENE ECHINOIDEA.

PLATE -CIII.

DIPLOTHECANTHUS ROSACEUS (Lamarck) (p. 219).

U.S. Nat. Mus. 165693.

FiaureE la. Lower surface of the test.
1b. Posterior surface of the test.

SCHIZASTER (?) STALDERT Weaver (p. 221).

Univ. California, type.
Figure 2. Upper surface of the test.
332

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CIV

PLEISTOCENE ECHINOIDEA.

PLATE CIV.

DENDRASTER EXCENTRICUS (Eschscholtz) (p. 223).

Wagner Free Inst. Sci. 2473, specimen A.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.

39800°—15——29 333

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CV

: Hite :
by H} H
yj Up

PLEISTOCENE ECHINOIDEA.

PLATE CV.

DENDRASTER EXCENTRICUS (Eschscholtz) (p. 223).

Johns Hopkins Univ. T 2, specimen B.

Ficure la. Upper surface of the test.
1b. Lower surface of the test.
le. Lateral surface of the test.
1d. Posterior surface of the test.

334

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CVI

PLEISTOCENE ECHINOIDEA.

Upper surface of the test.

PLATE CVI.

MELLITA PENTAPORA (Gmelin) (p. 225).

Johns Hopkins Uniy. T 3.

we)
ol

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CVII

PLEISTOCENE ECHINOIDEA.

PLATE CVII.

ME-uira PENTAPORA (Gmelin) (p. 225).

Johns Hopkins Univ. T 4, type.
Figure la. Lower surface of the test.
Ib. Posterior surface of the test.
le. Part of an ambulacrum, X 6.
336

U. S. GEOLOGICAL SURVEY MONOGRAPH LIV PLATE CVIII

B. DENDRASTER GIBBSII (REMOND) IN UPPER MIOCENE (?) BEDS, K. W. JONES RANCH, KINGS
COUNTY, 20 MILES SOUTHEAST OF COALINGA, FRESNO COUNTY, CAL.

INDEX.

Names in i/alic are Synonyms; figures in italic refer to illustrations; figures in black face refer to descriptions.

A,
Page.
Abert; J. J., species named alter..........-..-..-.....--+-------- 187
Acknowledgments for aid.............-...-.--------+------------ 7
JME CRIA) GEVENG oes scccaccocuEdses -copssepSanebcoobenssbicosccoros 175
CONE GH So cocoate sguseseaSccn cos Reco RsUenoSSeubceadossas 174-175, 310
GROAN: co gaceossanoded co ncesmodegocHEboeeSuSEbbobennesem 175
excentrica A. Agassiz..-...--.------ 212,
LETT Di Baas ene see a5 174
poriferamee =e Soo pose aces eSenaSED AOE DSSROSS sae 212-213, 326
Aldrich, T. H., species named after......:....-.--.--.----------- 173
Ay AUS ANNs Soccoqreassone cooaeoc SSeS E SES Sor ceeceebeEeS 165-166
PATIL CANES See ese oe aera ale iat teie cial te sicle etcetera 165-166
Tails. ket ak eooaAeacacasae SaSAacnOseeaGaosS 165-166, 305, 306, 307
Ampludetus\ampliphorus. + ------.2-.--------------+-----+=2----== 214
(TONLE Ra 5 seo a SEES SOs Son ORS oe BOBS OSH ssa OoS 214
ONENONOLS eae eee eee ae ene ais eee (ese oe 213
virgimianus ...------- seg) 2183
Amphiura sanctzecrucis - -- - 178-179, 313
Amphiuride.....-.--.-- 23, 178-179
PAO CHYLES! CLLCLULS seater eta ia niall alcool oe ele eee fell 83
RUA PAe oki on tana sede asansecenobea sanse cod aco sop aeeeesecoore 71
JPMDUTE To aesentsece 5522-2 5s30e 2 ssa seareocqsasseeapsaBseds 83
OnE Ro og eseanceban a secbcconerias ASnS RoE See Se sees saan 81-82, 264
UWO>MDIED ie cognenodoamoconse soo dadeeenes ABeSuEAgeouaSbooBES 82, 264, 265
SPeodosacsosseoosscriessszcosscaccpcsnucscedectcoascarounessess 83
Anapesus carolinus. .---- 222
Anderson, F. M., cited... 140, 185-186
species named after. -183
PAMILOCOMIG aerate seme ee sete ee eee wine oe wlcteneiclewinice cee ais 112
Asean GES NECN. 55535 need secu soscer be Hee Oo eEeeeeeeaoouS 190
AMI EAE Git IROU Son cc onse2s25cébe50c doocecerosncosospesseEeosos 117
so dosss cdooo ss or egg ncooodsbeedaseddsdodououeedcas 180
117, 158-159, 180-181
SAT DACRE. ns eee eee ae eS 31-32, 52-53, 117, 158-159, 180-181
Arnold, Ralph, acknowledgment to.............-.---.-..-.--.--- 7
(Cite deere see ee eee --- 114, 158, 178-179, 223
speciesmmamediattersascecsrujas--e ce aee cen bce ercine 182, 192, 200
JAY ORNE ORG SINS S 6-558 socest sess edsce a seeeeeedodsecsese 23, 230
A steracanthion lincki. 22%

WHI ~s oncocaaaap sens sé ance = ScusencncmeBeoSeeoenOasEeO nes
Fk cccctoseonasdocscesoce sSs050 -oce osenoccosscsntacsocnaccosss 112
ING PNR GYEAS as 6 oi ae eee ess AA ae a a 28-29, 112, 178, 222
Asternata .. . 34, 67-81, 140-150, 165-174, 211-212, 220-221
IAS PEN O1G C8 Siesta ote rapa = eee saree nie meena eel 28-29, 41-43, 112, 178, 222
AMOS IDS 5005 bonebbososcess os no rs aoc eno SE eesseuasacessesencos 197
antiselliseee ooo oe os ees Seite Sere 187, 198-199, 200, 203, 217, 218, 325
DM LSEUD Vans CTMOLD PACK ma ool te tal ee sna 199
199-201, 202, 204, 324
210
fernandoensis - 217
jacalitosensis - - - 200, 202, 203-204, 324
merriami..-.-- 185
Ua bacco aceee se caig gabee saben seas oben paseo sea oceCoSce 190
UMIGUS See ese cs ened ste ne sa 199, 202, 202-203, 210, 324, 337
Wann Seecee Gna ee oneaeensosetope=sem 187, 199, 200, 201-202, 203, 324
UD TTT Slain sams Bee tS BESS TONE Oa Be AC EOS HOON ECOG morc ASaaooS 199
sp.a Arnold ....-- 192
sp. inde. Arnold. .-. 182

Astropecten montanus -
Astropectinidae
Atelostomata. ..---------

JNINGRISCED Se con Soeseadenecon ened be Beebo nb aoe peaseeormaeadts 42

39800°—15——30

B.
Page.
Berry,,B. s\Wi., species named afters --:-2---2-2--o----------eee--- 220
Bibliography of Cenozoic echinoderms. ...........-.----------- 105-111
ofMesozoiclechinoderms)--eemee == eee eee eae ese 14-20
Botriopygus alabamensis ee
elevatus......-..--

Bourgueticrinide - -...
Bourgueticrinus zqualis
QIADUAMENSISHE Bete Sets eee ae Soca esata en ae tatoo
OLD PICU sais eet aeration a torca ioe ce nae rate oe ea nare a weet se 40
Breynellayequizoatarsti.— pes sa eer ee eects cae ace asia eee ae 148
PLC LOLA ss soe oes aeinak PASS e ere ess see ecto ee 148, 297
Brissopsis californica 214
poriferus . . 212

rimulatus. --

Calycina
Cardiaster cinctus. - - 83-84, 84, 265
curtus 84-85, 266
SFUTLDTLOEULS eereretaias eater CSpaS send daspabossumadosdcabaosne sé 83
STNOG KL ere ee pene pe daar Pa reich Ste eae eT Slee aot ee oe eae 84, 265
asSidulidasseereesee seers 34, 72-81, 140-150, 170-174, 211-212, 220-221
CHSC hE NAb NS. | Gogackeosshscugeboeaecascecdodunaceasessees 81
axquoreum......- 75
eequoreus - 6, 80, 211, 212, 259
amy edala nat saces ie ster esa cenrg stem oes tas semen maa 147
LECH De We Beton asm becaRcmcsdee Hate aer oo same ee 211-212, 221, 324
: 212, 220-221, 330
(on Diy nO -'6 6 cedesebbee seca de oesbedcbiSscocodsceeasassed 140, 294
(CONOId CUS Maser saat cnt ae aetna 80-81, 256
florealis......- - 74-75, 76, 259
hemisphericus. - 80,263
infermediuss cee eee bs eos Saeed Se eto eee we 79-80, 263
ATCT OCOC CUS pene tassels etter 76, 80, 212, 260
JOOMLA. Shee abet shod disease sbaeceosscesarceceeeeess 78, 261, 262
SCANTOM rs ae ee ene Sine tere cee nice ame ee SERS OE 79, 262
Subangulatuse A seems sesh wemetsiste aac eos eee ABee 81
subconicus.... 75, 77, 77-78, 261
subquadratusi. coe nee ce oes seat cee Sees ee 77, 78, 81, 260
(Pygorhynchus) alabamensis ---- 172,172-173, 309
Gadaylingasiis oe Ssasaoscacseneoseosebaceecae 146, 146-147, 171, 296
CODE AC Teetrss ae seit eee ren ae risee sears aoe 145-146, 147, 296
georgiensist eo. . {sewer ree encase teee 147, 170-171, 508
PeovbU elit Se pasabecascaueenOeUEeenBaR cei 171-172, 173, 308, 309
(Rhynchopygus) depressus.---..-.--..--.-.--- 143, 144, 144-145, 295
110 Lk CS eee 140-141, 294
lyellicaee -. 141-142, 294
patelliformis. . . -- 143-144, 145, 295
_ raveneli -- 142-143, 145, 294, 295
Gatopyeusicolumipanius ae ees se sessed ees eee eee 73
CONTAC eee ee eee eee SI ie See eee aetatae 145
oviformis - 72-73, 73, 74, 258
patelliformis . 143
pusillus. . - - 73, 74, 258

williamsi-. 73-74, 258

Boat ie ce asasheb4 = snco Bobo nomSct it cocoons ende> tocecoaanesens 74
Cenozoic echinoderms, geologic distribution of..-.....-.---- 101, 102-104
Cenozoic formations, American, stratigraphic position of.......-- 102
(CMBR Go) 5 sae coptanens csobocaoancctc cninhasasonapaconacoostcane 177
Gidarid cones ss eee eager te cen es 23-24, 30-31, 44-49, 113-116, 157+158, 179
Cidaris alabamensis 116
Cidaris armiger....- ase 46
armigera... wes 46
blandisthe cet eseteeee User er eee ce sacee cae ees aces 116
(DrAD Meee eee aoe eee ee ees tee eee see 45, 158, 302
Califormicus 5,5 feececisss ssiecae oe enesisscs saeiseceeeoeecaes 30, 31, 233

ay
337

338 INDEX.
Page. Page.
‘GidanisicarolinensiSeeeeren eee nCee eee eeeee eee eeeaaeee 113-114, 114,284 | Cyphosoma texanum......-..-.....---------------- 58, 60, 60-61, 61, 250
GMA Abe pacodcod sa eobeconaaaseneeasosnacepacessoosaasseRs 56 ROCK Rees on aco esernaesmomsqonosancseccssascsssosesess 60, 61, 250
GIGUT ELL TIS e ee See ee Ae ee a eee a COLES |] Ohpalosoaneyn Glens oo Sones seserinse cee eosson+ ssorpaoesorese 59-63, 118, 159
dilleri...... 23-24, 230 :
(iia Tiel ten ae SEBBB So eR once nannadeas uEEL cos seEE Seasons 47, 238 D. ;
PROBS oan 35 oscasencs seassnecseesse>> .... 158,302 | Dall, W. H., acknowledgment to............-- pedaaseeeerecaenace 7
hemigranosus...-:--.--------------------=-----=----2-27=-7-- 48 species named after Fes) 164
Terniamils ese Sets eee eee = SOUS BSE CAVA || ID Yes IUfoya TOS JEL OuGIe se ase cos ceosccconscosaceascesscce Bee 39
SMA MMe ee een tnoonaconaacosue cosa sesaanesass 113,114,284 | Dendraster 190
modestus.- 115 BETIOL GT! La ys pe OEM a EL eee ere 191, 192-193, 197, 317
moereus.....--- ESTIICY Teme eee Se ee eer Se total eae 193
TOMO MoAusasoacsoo cc ose mast cons pa soacooR ASS SSS ceNSIES COMIN Sa. C0S 15 pee ee ees eee eee etre 193, 194, 196-197, 225, 319
nahalakensis. EX COTIUnICUS See eee eee eee eee eer 194, 196, 217, 223-225, 333, 334
Ordina tis seer e eee nese eee Ee a fainbanksiles nee seen aes sere eee eee Aen eer ree es 217
OMRON OS 355 sn oesgecosdossaeeescsse EO) ) Caer MCR Ne GC BOe po Hane Lt A donadcneqersooSsoaceaarebeeacasecd 217
plumasensis. - PD OSI YE Ae oaeee senaumsanoede ducgaseonsaeas 193-195, 196, 224, 225, 318
pratti.....- 114, 284 interlineatusr. sc Ace eect ste eens ooeee 185, 195, 197, 216-217, 329
sceptrifera.. 45, 56 ONEE OMENSIS SE oh cre See eee tke eee act ee staieeaise aan 185, 195, 217, 319
SOE han auee ane dee ce sogdorigeeeedaeacs 47 perrini..... 129, 190-191, 192, 193, 317
Grantliryekocgunedabesoucdouseenanbesseucbemesaseconse CodacoRaE 47 Gokeudasod 197
shastensis -. 23, 24,230 | Dendrocrinoidea . _- 21-22, 25-28, 35-39
Grillin see seen ML Ma Sna au senpagcoesoousoCesaedtosomlag TE ABA b AD YER PIDs (hela acto ta eroaue warskweciMentacaanescnensaseccnoon. 67
SNE WG ONS 4 ooo aieeaseaesee=suscadseconsasayacseqacanc 4640-47288) Diadema texanas \aa4s se eeae secant ee eee eee eae eee 60
fay lOTens 1s se eeeee eee renee 30-31, 233 texanum....--
HGhoNMP OMG see cea debac Loucaeaanbcess cise sceausz5s05sceRe 444938) ||) (Miadematidaan. sass encte tes ce cee se Ree eee ens aaee eee cee
texanus.- IDE EON, oa Sona ceéscoonsoneosssossoseedsdase 32-33, 54-63, 118, 159
thouarsii . Diademoidea.....-.---- 31-33, 49-65, 117-118, 158-159, 180-182, 216, 222-223
walcotti.. Dicyclica --- 21-22, 25-28, 35-40, 112
Ey rTS aya a i ai OL on eRe Diplopodia hilli 59
sp. De Gregorio Streertlyitzit versace eee coe ete eke ee eee alter 58, 58-59, 2.
Cidarites armiger - . - PVE soa mea cones sssepvossosocenessecgs2s2sscnassscets=scee2= 58, 249
diatretum. (PHT ned mca nan conse =e oge soo aHboneuas Seosecdes saesensasee 60
splendeus LELONUM seme eee eee eee eae renee eee Bene eee reer 60
(Cidsroidease et sheen eeer eae aeed 23-24, 30-31, 44-49, 113-116, 157-158, 179 | Diplopodiide..-. 58-59
Clark, H. L., cited....- Medeneshioosedasees 115,179 | Diplothecanthus dalli.............------.---------- 218-219, 220, 328, 329
Clypeaster ambigenus..........-.-------------------------------- 138 MOSACCUSS eye Meee cee eek ce eRe Ene ee tec eee eee 209, 219-220, 331, 332
Ibiannitzensisee eee eee eases eee esses eee eee a ete Ease eee 1385 eDiscold CONIC enTLONinee eee errr cet eee ee ee See ae ee eee 167
TOW GSS cagesesadaose cabanssnSonseoas -pedEsSeecéasaeccso5550 PLE CEAD. || JO TERN Gal ittts ace tons sasena=-Sseceansosnesaceusaccossce2 174
209 | Dumblea symmetrica 64
_. 210,325
=a 38 E.
SanrdcantidadacrogdaosesobscossoousoxsEadcescoracosoune IRE) || 1oeioutoeyayNS Eragnibwab Is oso seme soeoneeeeSscsecssessooeesas iE)
joousdoseore sadaegoocenocuSuaaaoseasesoonbeCeeex 219 TD OTNISSC 1 sees ee ete ee ee re eee
137,138 georgiensis .
af 74 mortonis -
189, 211 IGPU Te om = Sb oemsoocss5s2 35522 S822 3S 3 oN Ses seccwsassescc 128
geometricus.......-------------------------------------------- 72 TRO sc 205 hao seebese cdeci= sanessoSeaotaseSsecescaasossessnSs: 136
JONES... ~~ 22-2 = nee 137 YOSACEUS..----.------ 22-2222 eee ene eee eee 219
jonesii.....---..--- +--+ +222 2222 eee eee eee eee ee ee eee 136, 137 TOSACCUS - . - : 219
(RUG OD soscasessesoesaces -Feesecco0s ss0ees5 toosees 128, 136-138, 293 IS DI CaN TAG US ee a 139
TOSQCEUS . . - 219) |) Mehinanachnius: <--2- 2-2 a a = ne = 124, 190
simplex. - 138 GANGNO seoanccenses 22o eee sos aos tesa ssebsssassatssonssce =. 193
ELT TUCCULL SS eee ee ee 136, 137 brewerianus 210
PO US a snes ecrlecoe Seb Se Ea ROR OL OBESE Aus SeeeseBEE EES coSS ees 137 excentricus...----------
Ease ae esate eden Metra claret ot ae CN VR MLNS Ae al 72, 74
Clypeastridze 67, 136-139, 209-211, 218-220
Clypeastrina 39, 160-164, 182-211, 216-220, 223-27, PAN ATT es SO ne ate IU Se Up area SEB ERN a 193, 196
Ccelopleurus aldrichi. - 158-159, 302 juliensis 125
CPEMBSVB 3 coc ceassssaub7t soos dwsosesddscboeseceosesoccdseocz9 117 norrisi 186
improcerus 180, 181, 313 parma 190
infulatus --- 117,285 sp. Conrad 197
sloani-.......-.- 181) (273) |) Hehinina.-------- 2 26- y-- = 63-65, 118, 159, 181-182, 216, 222-223
(PAD ATS) WTO 5* s 30.56 5o0dsaciecuosdecossbsessccessseencos 117 - 69, 256
Collectionsistudied@ees recesses eestaeeeeneeeCne err nee reer eeenee 7 bbao 71
Coptosomssmontonie sae see epee ee Eee Renee eee 62, 62-63, 251 @XPANSUSL se ae ae tae sec eae ke sateen aus NE 69-70, 70, 257
speciosum... .. - -- 61-62, 63, 248 (OPEHNUE Ee aoa qudescsosconusecasacmadeesssaccnascéscccoodsces3 70, 257
(Choy unlohin, OVI <2 = cone A abo see bos cossoadasuoseroosencoondeas=a 57,249 | Echinocardium ampliflorus - 214
Couper, J. Hamilton, cited by Conrad.......-.--..--------------- 145 ampliphorus..-....---- 2
(Chemtairal, JD Wien @lieel = 5 cess eceosdeee spounsse - 34,47, 57, 82 cordatum..-...---
Cretaceous echinoderms, descriptions of-.-.-. _--. 35-100 Gepressum <2. 2 one se ee a ino
stratigraphic distribution of, in Texas........-...--..--.---.- 14 I OCHICUIS Sess ee eee eee er ese eee eee
types represented among..............--..-------------- 9-10, 12-13 orthonotum....-
Grinoideaer een sso ese asses an meee ieee 21-22, 25-28, 35-40, 112 orthonotus .--.-
Cryptozonia.-- --- 28-29, 112,178, 222 pennatifidum. -
(Cry phosomayhil iter eaee re seers =e een eee eee ee eee 59-60, 248 DUNG UTULOUTULUTT oe toe
TMD Sas Seseees escabebal speseneedoocaaseesaaoceseeceasn=s 62 | Echino-cidaris infulatus.........---:--------------------
SDECIOSUNTL 3 202 hoe Wa Actes Shenae Steet soe aoe eee ee 61. | Echinocidaris sp. MeCrady.
(EU AS Sh Abbe bas OOO SUSE aa ca AEC OC SUPE OR EORSODES ASnaNSOsOO 60 | Echinocorythide.........-

INDEX. 339
Page. Page.
Echinoecyamus huxleyanus..........---..-- 119, 119-120, 120, 122,160,286 | Hemiaster californicus...............---------..---2-------2---- 96, 279
meridionalis 121 (CNT CS... a agorte Re Cian oncses2 Aare ep Eee ee aes 90, 91, 276
PEWS odode nesticnsecessoodnb-Hmonseassonasecenscaosoe 119, 120, 160 comanchele. sas. ---2s2..e 90, 275
LOAN Gee eee ener creme ot oak es acne eomans 119, 120, 160, 286 COT RANE AE ES Ae ea eae eal ae pene ea ee ae es 174
TOURER Loco: caters sondccogeanee od oedassasebesscns 119, 120, 160, 303 | GE oo oe cb Sek caceen ceria se aacocene5=Ssceeeanses 2 90, 90-91, 97, 276
BECHI NOUS CUS DET MB aes vee wate oe Seto te vanes nea cos eos cee 190 elegans. ase Sees Sane ee ES 88-89, 89, 90, 270, 271, 272
Echinoidea-. 23-24, 30-34, 44-100, 113-156, 157-177, 179-215, 216-221, 222-227 | BUND OCS 01S sae ee “12. --.. 95-96, 96, 278
PHC HINO] AM Das aALH UL Sabet ee eeaset eee ce cian eos sine 174 | IUCN CS SILT US sea a Sa ee ere eee ee ee ene 93
aldrichi-.......... ... 150, 173-174, 310 HSU 6 Le eee eee ees - 97-98, 98, 281
appengiowlatuseese sr eet ecee eee msn) Soest 149-150, 174, 297 LACUNOSUS Gees ie eee tN ou | aur G Woes ue Miran sea mln One eet 97, 27
FRI ye aes acl OR SCO E Oa ene ae 150 parastatus 92, 93, 97, 98, 277
TST Eis Ogee S Ga See SiS eee Sepa ae ea ee a 174 Stella Paaetece LA eye eran Wnt Siege ene ak D, 93, 97,277
PIC ON ec bs emeee ey See aera ee at Oe SOc ame Sone ke 67-68 UOLETNTS 3c hoacsoneddaaenornen ao adasesHesosemencncoaaecoe 94-95, 27,
Echinus andinus 53 UID Ue eere es So ee eee ea eae ae Reel aa 92, 93-94, 277
éxerceus.. 118 welleri------------_.. 98, 281
improcerus . 180 wetherbyi ah 93
infulatus... 117 whitei , 1, 272, 273, 274
patagonensis. 53 (Pericosmos) spatiosus 215
PLETE DOT US Secret ee as SOE Nee pp} || SSIES ECE oo oo mbt cas eeencc bene n -saecaceseeeoeoe 31-32, 52-53
PORALEMENT 0 PULSE eee EE Oe ee roc os See teehee 1Q1m |peLLernicidanisan tomes Censeee ees eee eee een ea 31-32, 233
FTC CET Re et nee RN ee Ra ye oa AS 124,190 | Hemipatagus‘argutus...-...........-.....-2.22.222--2---.- 150,151, 298
ACL ETUITL TE Seeger as eo oc NSS Ere ee 219 | SUT. OS [Ce US Spears Ee ae ee 150, 151, 298
ruffini_..... Rtas | meLera pedi nay chal tori sxe ape eee ae aI ne 57-58
variegatus. .. 222 | Heterodiadema ormatum ....................- -- 56-57, 247
Glose aan 118, 285 | Hill, Robert T., acknowledgment to................22.-.....--.- 7
SD WAU riC heme ee ee aR EL ts ence eek ee A, SLE Sia | EL OLESLETMCUICLIUS Sts Be. Steg Nera ore teen eG cath Gc ee 83
Spa Gunnin sham se ase dees re anaes eS RP 159) COMANCHES Se pee watt sachs Rema ne See eee ee a 85
SDE MON {ON eae sees ance nes Set Sa ntl Arete ee eaeaees 46 CONN Let Seater Soe 85
Eldridge, G. H., species named after............-.--------------- 161 PUTO Yt 008 ce aa ee 83
mm ons php enezerncited esas eaaere seen seen Se 119 levis var. planus. . Ste 85
FET UILOSLET ID UES Mere a oe ee as nn VRE RE te 86 MOTLONA «9-2-2222 = 22 goes HES)
TCATLLTS ee ee Re ee es ot vette. EE ed Al 8s (PUD sso mnonaesebeseasueccssson 85
87-88, 269 DU SUL ee eee ee ee = oe
a Wiegtdirs 87 SUM eae eo ean BO 86, 265 2672868
86-87, 87, 268 SUPCTNUS .----------------------------------------- +--+ +--+ 85
Eis Sgn Seo ees Soe aoee Eee SS68 Cone Se SCORE Eee ete sana 86 Ui Mis onacinaachestceacsosesscososscesececesssssssesscosceee
Encope cize 208 | Holectypina........ 33-34, 65-66
GMAT EIN ALA eae emerge elu sta cnn SE OEE anh) ae 2083 | Holectypus charltoni- 66
fama UGe Habe aaa daa bE eHehCORG AOSD BESS SaEeE Ceo ae mereT 208 craigini. ......-- . 34, 234
TTIECEOD HOLS eee ene eee re a sis eae 206-203, 322,323 | —- pealel....------.....-..-.--..-.-..- - 33-34, 234
tenuis. ..--- 208] Dianatus-..--------. 2... . 22-2... 5-66, 254, 255
Encrinide. - . a. DB 65
Hncrinusihyatil--------------------------- 22, 250 66
Eocene echinoderms, descriptions of.........-.---...-.-.-..---- 112-156 66
140
177
52, 243
i
IBIS DEES 2 esac Sonor pasdoanco nasa soedees sence Sesees 21-22, 25-28, 35-39
2 EAE a Inregularia......-- 33-34, 65-100, 119-156, 160-177, 182-215, 216-291, 223-297
floridanus. a 176-177, 311,312 ae a 21-22,
Eurhodia morrisii 143 Bayan: : 36
R-. F
Faujasia florealis : 74 MEV SAP MUD SS sopsacconcoisossscossostseeuseeesese senor sssedes 26
Fo aria meri GOW ANS pete eee ieee aia meee i= cei oe 121-122, 286 ER 26
BRR DoT a1 1 Cl 2 a eat a etal ater 1, 119-122, 160, 182-183 SST G1 ae 21, 23
SSH GScay avi WE Se ee cee Ao Fn eg ae en ea 39-40, 112 Wy WLLL = LOTS ON aera sats ne eee eran eee 26
G. SS ee 22
Gabb, W. M., cited... - 178 uy
(GaeaniaameniCangan ss cetera ecm ese ce ia! soca ee eh atacuer oS 159,302 | Jurassic echinoderms, descriptions of ......-.....--.-.-.-...-.... 25-34
Gallenitesloresonensiscswees sees eel een See askew eale 28 ee 212 SCALCLEY(O fee erases ec Cetin arate iat ia tine y= eaeee eae See 9
Geologie distribution of Cenozoic echinoderms. - types represented) am Onpe ree a epee eee eee ee eee 12-13
Gnathaster elongatus 42 i i
Gnathostomata... . 33-34, 65-67, 119-139, 160-164, 182-211, 216-220, 223-297 . ° ,
Goniaster mammillata 42.937 LOUD BOYES econo soe 2200s = 92 28ces Rees SGos cea ees reg sONS SESS 136
Gonioclypeus pasate piel Rotts Lek a Sires 81 EIRNGES: coeds TAN Eke Wa aol TIDE E mee oeer ty re
z BA eee et RN sy eng at ie tee *, | Laganum archerensis. - 123, 161-162, 163, 164, 304
(SHREOIEB SES HET oc ia ac concy ssecave nese eob epoch <bsascaoks acodse ee crustuloides _ 122-123, 162, 163, 164, 286
ZAVIG eo Soneberaqt.c=ASSben ae Senr oe Sen S mee een ne 52-53, 245, 244 , a
ss + GENT taser ty ie Man aU os 8 HUE ayia Lee Sah Cac el 123, 162, 164, 304
Gregory, JouWieacknowledsment tO. 222-25 on -eneeeeee ae ee 7 eianiapei e Coeeet Oh es CAN Aa ee 160-161, 303
SMACIESMAIMeG Al beter teeste stata totaal ee tee eee 148 BISHEST CIR AME a TSE eS Cove yee any «eae 161
H. ALON ANU Sees eee eee 123, 162, 163-164, 304
ORANG MOTION saa ais ae enn Ce eee an ace ae ee 67 | 5] OD TIS ODS page are ete cee: eas ee ree el era cee ae 123, 162-163, 304
SFL OMTASEET OMEN ICON Sopa. erence gee ee ee eee 94,95 | NGI ON Gries She coeHeoabe nose AasncasO Sp reD Ona SRE ROS San 123
beecheri --- 96-97, 27: Leiocidaris hemigranosa. = ate 48
bexari.. --- 89-90, 275 hemigranosus......- - 45, 48-49, 239

340 INDEX.

Page. Page.
Iheptanba clakeesssssaeeeerereerrrct eet st odes So ee Ae cee eens 538i nO phiodermatidas-ee Seeaeee see sece ee eee oe ate reer eens 178
argutus 53424505) Ophioslyphaibnid gered isseee sess eeeee seen eee eeeeee eens 43-44, 937
inthiayalal a CNS 1S eee eee eee ee eee 153, 300 HERE § scot on gnseoss> sotoancoscecesascsscusoassossssopece 43, 44, 237
Califommicasie. (pees eee ose oe nee ae eee 214-215, 327 Utabensis=s 22s. 2. -- eee see ess Eooaseannases Ley Le?
Umi wlan se forse 2S ee eS es ee ee eee 995100528211) O phiolepidid ses: ssa sees ences ees ere 29, 43-44
variabilis. . ... eee ene aS ed oe - 99-100, 283 | Ophiuroidea..... 23,29, 43-44, 178-179
WAlmine TOneNSIS Hees oe eee eect eso oe ee eects 152-153, 299 | Opissaster conradi.........---.-- eae aaacnss willie
Orthechinus pretiosus........--. 118, 285
M. Orthopsidse (2.9.5 alee ee Wares aia a See la eee ee eke pitas 54-55
‘Macraster teranusaccates capone nase n nse eee eee S8i8 | OL EHOpSISFOCCiG ent alis meee eye eeseer eee nee ene ea 54-55, 246
ICTR TORT (OLE DN les 55 aaa adaceadend2.daseensosocce saseuase = 206 jDENUWEN Ree orcince sis seo SSS eUeSaRneSee Sonn Aimer ansednitog 54, 245

TOVEN ELLIS <5 stesso oe oe ee EE SR eee eee eee 206, 207 P.
Macropneustes carolinensisys. «.a. sees seen sene eee aes TEU LOOD | LEEXO sys Wien (Tole ae ooo sae soba secobssonooncesncenssbe be JNM Aba Zl
1s 0) 0) 1 REAP Nes Rin ee aE) a ey cea arte heey Ae bd dete a eh 4 1555807 sie haractino pod aaltepet eae Met ee es ce ae eee ee eee serene 177
Marsupitestsmericans= eee se aee seer eee eter eee an ene eae eee Eee 395236. | Pedinides sas2 Jas fara. Ses netsh tS aan era eee Nesey = eae 33
testudinarius.. . 39 ll Pedinopsisipomdlic eee cess cutenetemiay es ue as sea aes anes se oe ea 65, 253
Marsupitid 39 symmetrica. ... 64, 252
IV CUT UID Sates cradles aoossdEw BARS be qeOn OAC HOS oEe Ss eeooaS 225 9 226M | le exe CAL OS! ASD OL ULES eyestrain 42-43, 237
caroliniana. = 204-205, 226, $20) 8271 || Pemtacerotidee. = 922. ote eee nen ee 42-48
earoliniata... Pentacrinidee . . 21-22, 25-28, 35-36
pentapora. - CP ONLGCTUNILES) CSLETIS CUS) eyaiaya (ae ste tae eee eae eee 25, 26, 27
quinquefora. Peniacrinus asteriscus.......-.--.-.----2--.--+-- 22, 25, 26, 26-27, 28, 232
sexforis OPEN NAGE, coool Sooo bondanedacheqedneccnbados=sescseessonness 26
testudinata WPI Soca obese ssaucksosocubosssosecoscesqeesensssanas 35-36, 235
Lemmas tet or NU nah heh MS a ON Foe oy os Ar a eet shastensis - 27, 28, 232
MMT COMALS DALIOSG els senate Se ke ols Se ae RN a 215 head Ae SIS pete eee aie ee 35, 36, 235
DENETICO SS re eee eR era A LTR SET Nae Shae GN peaa NYP Baird 215 WILE Le elem o en secisyayetars ste a eon eee --- 26, 27, 27-28, 252
Merriam, John C., acknowledgment to...............--.--------- 7 (Caimocrinus) andres. <2 2 222232 ee eee 26
CAL Fe{s Leek OTANI LT Ee Ihe CLM be Meebo 8 So gt 18 180, 216-217 | Pemtagonas<er arculatus..-.......-------.----------...-..---..--- 41
PMenraa Master Penni niece ees ee eee ee ee eel eee Soe ee eee 190 TOTO Wy eee aa ala apnea eat on 41-42, 236
Merrill, G. P., species named after..........-.- Bee 1659) |(kelitazonas tenid este se eee eee eee eas eee eee 41-49
Mesozoic echinoderms, geologic distribution of-.......-.-- 45 TOG, |) FRIGEMAMNS 5 oe ocebsec scene cessssea ssacacssecosceecdascesanesese 130
Mesozoic formations, American, stratigraphic positions of....-..-. ll ENTS cop sa se pperes bon ecoScs 25 oCsasesoos=esescodaas 130-131, 188, 287
Metaliatholmesis seo ee ec Cee ee eee ce 215 ICONDTIVEN SIS ea ener eee ae ee oe eee ee 204
Fra rOMel LATTA ps eon eee NE Cl Se eRe RTC uM ORIN nf ieee ei 215 CN UES EL OU E Sw etal oat ote ote ee 122
EM ACTAStET UNG ULE ere oe ere ee ee eee 93 lyelli.. - 125, 126, 127, 130, 131, 131-133, 136, 188, 290, 291
SMACTOGHIN WS COT01CILS eee eft ae 112 OMAR UT OL So ees 127
BUTT CKOPOS 1S 1111 eit C1 So eee 63, 254 (UIE EHS NSIS S 6 soo cS s5s0s0esocspeseaes - 133,134, 135-136, 292
Millen 7S GAC Cited eis acioss eect etae emusic ts eee at sersratayeran siete 39 (UL oa snedesss00 223094380 3005595205 Be ein enim a mein eine 121
Miocene echinoderms, descriptions of............-...----------- 178-215 TOHOUTEY SES oo Gesso9 aco ssosmaasasneSseoses 133, 133-134, 136, 291
CET MLACHeS1S see eee ee eee Rey SDs (2 Shire yale no ooo pmecsosss noeacouacsessosooncecadesson0es 132
Monostychia marginalis na Yl Gid> WOE 5522 095 cccasseodacens cancusoscossecsesaneeses 130
(OTR ss osasesscse itor eee eriasten aus tnalishereser en pee sees e le ee see ee ee 95
Mono 54--os-scensesse PEST OR) ee CTCOST UES |S DG 7108108 neers oem eee ae eee ee 215
quinquefaria ............. . 128,130, 137,191, 289,290 | Phanerozoma.............----------------------2-+-- 2-222 22s esse 41-43
TOG ENS Cee eae ee Mee Are NS) 2 Dua cece iol we eaten CURE Jog |) Phymosomoa temanan: oo = on ee 60
MOTLOMIGED CSOT er eee Ree eae need CML RENE He ea Ra 198 | Pinnata.........-..-- - 39-40, 112
GONEST Te wean epee FIL Mee UMN Neate ge) |) Erlagiobrissus)MOlNvest =. on 2 ee ee ee ate eee eee eee 215
QUANG WEAR ID Ae era etme awa Ge dae dain ef eee e Ee 128 ravenelianus --- - 215
POGETS TA Nisa ete a ryder aa aad dn nye 128, 136 EPIAMIONOLS) AVENEL MUS rane eee eee eee 0215)
SUTITD E taaiee ox MUR ten Sore aoe RADU Men a nAmEN Oe Ris LUA 133,137 | Plagionotus holmesit.....-........-..-------------- +--+ 2-22-2222: 215
LUG 1 Ns NEN Peet PBT go ert ee 136, 137 TOOT RAT DU Ba 623 3380555000950 59 593) s2Ssc00s6eS0S5sss025e5c05S¢ 215
(Periarchus) carolinensis...........-2--2---2--02--2-22-0ee---- 994 | Pleistocene echinoderms, descriptions of..-..........-.......-.. 222-297
Fe ASS feet aN _. 131 | Pliocene echinoderms, descriptions of.....--...-.............-- 216-221
126 | Psammechinus cingulatus..........-.......----.-.------..-.. 63-64, 251
135 CRONIES oS ocsbdeaccoeer sesso 99S soso sos0e scosne =ssscnsesee5 182
121 COOMBS s 333 adap so eesodaosdsncacosososdsscosSsdecescessons 180
philanthropus . --- 181-182, 313
OU FUT oe 181
mq | Pseudodsademay baileys yee ooo oe eee eee 32
71 ChE WWE on soon qndcens she sazees2eeae-saseoacesssocqomess 56, 248
141-142 Merson oe Noes He Soe Ree nce aeak cred ete ee 32, 234
171 DALY Ae oC Uh Ate os atlanta aL eo aR 59
OVI FOTIIIG Mn sy MN Nel aU ters ph SAN ARC ea Te Le RE 72 ornatum 56
Nucleolitide . .- 68-72, 165, 170 roemeri 55
INA culites\crance yer aye sel ts Hae tsay ans kat AW aoc eo) nt aye NE val speciosum 61
CTUCH PET Suess Nm MLE on tei rahigu Ive NaS RE ATS PS DCN Lor aba val tenue... ceceeeeees 55
xf texanum . - 55,57, 60, 61, 247
0. Bygasterid as 20.0 cee yet a rg sae guar tieneie See ade 33-34, 65-66
Oligocene echinoderms, descriptions of.........--..--.-.---..-- WENT | eee OTA TLCUS CTULCI CTs area alee eye eee tater 71, 142
eastern Gulf, stratigraphic distribution of.........-....-.... 104, 105 (OUD oa seteoncceqo sss ae dos tacos seo ooesedseeucocecusdeccats 171
Oligopy aus lcs eS Ue ales ie aera ue Disa pe See ee 166 @TISMOMENSIS: 2 yet Ss ein Ie eats ee aero oo 146, 171
ostubat sees ae NE Ae ARC NBA ise Sens et aR a 167 LUGAR Rea anemne Pica a acosor sssboeesadsos sp atoseoee AS oRoceas 141
WGI T INE Ee oe auc oobanaasseue Seboa=ncenemcce 167, 168, 169-176, 308 WMEMGS 566 -Sasocoessebasscos=seeesooosscesosespecessccooos 146, 147
Shaldermianisoyseec ee npc ene Me oc peste a 167, 167-169, 170, 307 mortonis 67
OVUMESCEDEDILIS oe oss roses Rene eile Se ee 167, 168, 170 TUgosUS. - 147
wetherbyi--..-...... . 166-167, 168,170,307 | Pygurus florealis a 74
Opinodenmaxoridgerensts setae - epee eee eee eee eee 43 EOOMOUTICUS 2. | 3a ee Nee eee eee nee 72
SDcoadebsocesosocesnssecesndenssewubsocascaesedesoScasadse 178, 313 Ge sdsosdssissoo*cesdnssosseqobagsshesoezesskcossserecousses0 34

INDEX. 341
Page.
PUTING OUILOILeS Seer asf ae ela sseis oo aise eesiisiee anemone ace Sa WactitellarspaConradeeese see eee ae een eee
ESTILO ULLLIDS Heese serene tree aus Zot a) ees oe eae 68 SPs BIN OSE oe ase he eee oa oe cine
[SUMS po sense ao saasoset tsb SOUO RRO IRSE RBA aeAa as aabeeSaeS 67-68, 256 (Echinarachnius) excentricus
OT EG OMEN SIS ie ae sees So ONE R ieee os aa one Be ee
R. ( Mortonia) rogersi
Ravenel, Edmund, species named after.....-.........-...-.----- 142 | Scutellaster cretaceus.
PROMEREMONCTUCI ET etree ae eae ee eo Sea tN eT UL 142 | Scutellidae...... - 124-136, 183-209, 216-218, 223-297
FOUL ee a eee an ee en, NS es Loca scence eee riley ees es7 WOT aah es era eee oem ee eee ene 130
Ravenellia macrophora. e206) antillarum.......-....... - 164
Rezularia ectobranchiaia..... -.....------5--------+--2---0-- - 31-33, ST) 182-183, 183, 314
49-65, 117-118, 158-159, 180-182, 216, 222-223 coalingaensis 183, 314
Rezularia endobranchiata........ 23-24, 30-31, 44-49, 113-116, 157-158, 179 | conradi.......... Hotes code cemaneRsoauqaAclLwuneraaceseacna ge 127
Rémond, Auguste, cited 211 crustuloides............--.. Jesnsenesese Seas aROBSeoDSeC econo 122
ihizocrimus|alabamensis=..---222see-@e-------2-- =e -o =e 39-40, 40,259 UA eo occonem onesie seo cans Se neeees Ss a08> cds aasse ccs ose ane 131
@rihinahhape S.2s<Sbesccaaeds aocca a coeSene acest 40, 236 pon a 1 2 Se a ee 123, 126
TRinr mG nayep HSU, soso cececsoetbaceeaesecc eee saeee aebab esas 143 merriami.... 185
DY RETIN 1S Se ee ee er Sirae Oe Luy ies gees A 145 pileus-sinensis.......------2-------=2---- 2 135
- ‘ js Gosbosacbosasbeocodas see neseben se BS 121, 286
Ss. Slocum, Arthur Wi:, cited -...:-.--.....--..-.- -.-- 79-80, 80,97, 99-100
Salenia bellula Spatingid ce ees eee eee ee eee ee 86-100, 150-156, 174-177, 212-215, 221, 227
LOST Re ee Tie aed oe NN A ok ay tay Val SPaitang ws! Colum blo Un eee eee ee 87
etal erases see ame Oars | co ae Uy enn COTM UT UO ata etna a eeaeeee 92
scutigera CMM NOW ce eeedisaa soos ou seaings aa sbedtceeceremasssbeesosa= 213
texana 49-50, 51, 241, 243 pachecoensis.-........-..-- 2. 2+. 2-22-22 te sence eee ee eee 156
na lil eee eietee eects ees eset steno 50-51, 51, 242 parastatus.....---.-.----- 92
Saleniidseyan swe cows fe si coasts eee ese ewes a Ee sea 49-51 Stell. ----- 2-2 -- 2-20-2222 ee ee eee eee eee eee = 2 $8
Sarsella gregoryi-.... .. 155-156, 301 et) 83
SGbizastenamen Cana see esn eet eee ese ene ci reenaoe eee ele 176,311 | —s- SP------------ +--+ +--+ +--+ +--+ +--+ +--+ +++ +--+ +--+ 2-2 eee 83, 92, 93
ATI POLAR ee ce tee settee Geo iice tise .. 152,299 | Springer, Frank, acknowledgment to................--......-.-.- 7
TODOS SP eae eee eer a ee ha nor 207 (OWIG| Sess cede cag aeee: Son sna anateas Aswas sme ebEsesooe 25, 26, 39, 112
LOGIC ATITIS eee ener eA yy ely eR Ss 5 175,311 | Stanton, T. W., acknowledgment to..-....----......-.-...---...- 7
Taare EE gee dO nee ae 151-152, 298 | Stelleroidea.....--.....- onecouNaeconauc 23, 28-29, 41-44, 112, 178-179, 222
Stalderi 221,932 | Sternata.. €1-100, 150-156, 174-177, 212-215, 221, 227
SSeS GH SeE OS AR OR DB OIOE SY SEC SH OC SEER SORE aan 152,299 | Stomechinus hyatti- 33, 234
206 ECO UU CUS Se 33
206,322 | Stratigraphic distribution of eastern Gulf Eocene and Oligocene
SCUTTLE] Aenea Nan Hes PURER Lee ca aio et 124 echinoderms senses none ieee eee see ee 104-105
DOT Gee ere ce te eR Na Bt Tina - 187-189, 315,316 Stratigraphic positions of American Cenozoic formations.......... 102
alberti..-- 187 of American Mesozoic formations ................2.--...----- 11
MATIC OTS OD Toe eee ee a os See ne 183-184, 314 | Strongylocentrotide..._........-...-.--..-.-2.-+--2++2++-+---- 216, 223
CODUL-LITICTUSI See RU one eo ee sn Parn nee Peas, 135 | Strongylocentrotus drébachiensis - 216, 223, 328
caput-sinensis 135 franciscanus:s 2 =--- === ---— — 223
carolinensis 204 purpuratus. . 223
caroliniana 204 | Symapta sp...--..-----------+-+ + 22-222 22 22 sees sees reese sees reese 177
conradi... 121, 123, 126, 126-127, 293 | Symaptidee..-...-.--.--------+-- +++ 22-22-2222 22222-22222 22s 177
CTULSEULLOIL CS eee esse a tesa el ees eine 122
CET DM imcnan ches noc n Sse acs easel aoed SoS BB OB SE eneRU ee suReebee 223 as
184-185, 186, 189,314 | Texas, stratigraphic distribution of echinoderms in..-........-.. 14
ween eee e ener eee eee eee eee eee eee eee eee 130 | Toxaster elegans ..... - 88,89
184, 185, 189, 211, 317 ORO as Sasa speseos Sade shoaSacaseeccosa: -assosesasdsaedscs 86
coe e ete eee eee eee 211 UMGULD «2222 ao ao 2 awn nee eens 8D
(AUB oz conse coccesoe dss choses ses sesbessesecceesaesseeaeesens 1937)" "Toxopmellstesivanleg ats - = one ee 222
interlineata . PAGS | SURETY QDS GIL aks 2 <sansenasa=do~ Fo sons ee sae soseodecensecne 71
jonesii.... 136 cruciferus....--... -. 71-72, 257, 258
[La RORIET IS. ooo soca obacaces :setassens soo oeesesice 190 | Tretocidaris perplexa.........--- 115
(i Gs casccanoscasadh cotdos cdc Suh onecpececgoswesecuas 131 | Triassic echinoderms, descriptions of. 21-24
macrophora.. . 206 REAOR) Wb sdonsadessedsbdoaaascncssesstpeatuoscnopsussEonces 9
HI AB TM = oo gon ace2soecetsessewoaconessnecansass 183, 185-186, 314 types represented among: --=-- 222 --22-------- 2-2 12-13
TATE kaos ona BO a= es OSC PODS E SSE CEH Ose e Oe EEE eoe HECoees 1320 Riri plechinid essere ses ee eer nema nr ee ase 63-65, 118, 159, 181-182, 222
PNTISSISSID DICUS 1S ea ae eee eee eee 124-125, 126, 127, 133,288 | Tuomey, M., species named after................--..------------- 126
PILOT LONE eet ea asia Pee ea ee eee See ae Nae a claaisnes eee 128
norrisi. . - - 186-187, 314 U.
parma. .... _. 125,199 | Uintacrinida..-.......-----------+ +--+ +++ +++ 2- 2222s rece reese eee 36-38
PDALAS ONENSISH eee meee ee Os i inrs oe acer el er pul 125,194 | Uintacrinus socialis.--........------.-----+-+-++++----+--+-- 36-38, 235
Fes ee ee 190 Vv
DILERLS-S1TLCTIS 18 ere eee a = alate ete miele are ee ae ae ee 135 ;
TOE I OP Tod coe saeco seen sate sesscics Jesse 225csorbe2 Sse Soode 128 | Vaughan, T. Wayland, species named after...........-...------- 160
GPG AIC he gacses noc2 pees secuigornodeseceeose sds opteesseencee 225% I MAVIELELL pea tere Breed CLC Cl eee teeta eee a 222
rodgersi. 136 Ww
Togersi...- 128, 129, 136 ;
striatula . 125
striatula.... 224
subrotunda 188
SUDLOtraP ONAL sa. con's cosmic cticenie sens mw saaseepece seas 125 Z.
ateRO Css sesh sscesindan wadsaasennsoansasosse cosueeescua- TSSe le ZenometraiConoldeseecer sen stamens ene ae lalate oeelalalatointelsiele el aiel= 112
LEE Ak oda sncce ubbiodoasS aS HCO EIS SOAS SoOUTES 125-126, 127,133,289 | Zygophiuree 23, 29, 43-44, 178-179
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