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(

MEMOIRS

OF THE

MTTSFJTM OF TOMPAR ATTVT? ZOOLOGY

Compliments of FRANK SPRINGER

and

Alexander Agassiz.

CAMBRIDGE. U.S.A.
PRINTED FOR THE MUSEUM.

1897.

MEMOIRS

OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

HARVARD COLLEGE.

VOL. XX.

CAMBRIDGE, U.S.A.
PRINTED FOR THE MUSEUM.

1897.

«'■;■
>) 1

UmrmflTTr Press:
JoBM Wilson and Son, Caubridoe, U. S. A.

,"-'Siv'**'-S"^-''W

CONTENTS.

THE NORTH AMERICAN CRINOIDEA CAMERATA. By Charles Wachsmutii and
Frank Sprinobr. Chapter I.-IX. Page 1-369.

A-OVN

£[ttmotrit of t^t Pnatum of Comparattbt jSooIooq

AT HARVARD OOLLEQB.
Vol. XX.

THE NORTH AMERICAN

CRINOIDEA CAMERATA.

Bv CHARLES WACIISMUTH and FRANK SPRINGER.

IN TWO VOLUMES WITH EIGHTY-THREE PLATES.

Vol. I.

CAMBRIDGE, U.S.A.:

^tinttti for t&e iHugeunu

Mat, 1897.

Co tl)e illemorp

LOUIS AGASSIZ,

TO WnOSE INFLUENCK A.S TEACIIKII, KXI'OL'NDEK, ASH INVESTIGATOR, NATVRAL
IIISTOIIY IN AMERICA l« 80 DEEPLY INDEIITEP,

AND WHO FIU8T ISSI'IIIKU AND ENlornAOED US IN OCR EAIIUEU STUDIES,

IS ORATErCLLY DEDICATED BY

CIIAHLES WACII9MUTH.
FUANK SrUIXOEK.

.V.S^'SfeSi'S* '^^

NOTE.

The Manuscript of this work in its present form was received at Cam-
bridge for publication September 1, 1894. Although in press ever since
then, no part of it has been published until now, and the date of the work,
for bibliographic purposes, will be that which appears on the title-pnge.
During the long time that has been consumed in the printing of the plates
and letter-press work since the completion of the text, many new species
of Crinoids have been described by American authors, among which some
of those herein mentioned as new are included, and thus anticipated. No
attempt has been made to cover these cases by modifying the text, nor
have any questions arising upon publications appearing subsequent to the
above date been considered here. In a work of this size while in press
changes could not be made to keep pace with current researches, and the
date of delivery of the Manuscript for publication was therefore taken by
the authors as final, so far as they were concerned.

It is a source of extreme regret that my learned colleague and long-time
friend. Dr. Charles Wachsmuth, did not live to see the publication of this
Monograph, to which he had devoted so many years of assiduous labor.
Never a robust or healthy man, his last few years were almost a continual
struggle against disease. His strength gradually failed, and he passed away
on February 7, 1896, at the age of sixty-seven years.

Dr. Wachsmuth was a native of Hanover, Germany. He came to the
United States in 1852, and soon after engaged in mercantile piu'suits at
Burlington, Iowa, which became his permanent home. Failing health in
time compelled him to relinquish business, and for the last thirty years he
applied himself to the study of the Crinoids, first as a recreation and to
secure outdoor exercise, and afterwards as his life work, with all the ardor
of a scientific devotee. His keen powers of observation, sagacious judgment,
and indefatigable energy have left their impress upon the works which have
been brought out by us. While his death is a loss to Science not easily
repaired, it is to none so great — aside from his family — as to the friend
with whom he had worked in pleasant collaboration for so many years. It
is with a melancholy pleasure that I avail myself of the opportunity aflbrdod
by the appearance of his last work to pay this slight tribute to his memory.

FRANK SPRINGER.

Lau Vegas, New Mexico, 1897.

,:3i»r«'''pv;

INTRODUCTION.

The present work is the outgrowth of studies begun over twenty years
ago under tlie encouragement of Prof. Louis Agassiz, and prosecuted con-
tinuously ever since. During that time, we made two very large crinoidnl
collections, of which the original one, in 1873, was secured by Prof. Agassiz,
for the Museum of Comparative Zoology, Upon this collection one of the
writers, while an assistant at the Museum, laid the foundation of the present
work. Since 1877 the investigations were conducted by us jointly, and
during that time we have built up together the extensive collection which
is known aa the collection of Wachsmuth and Springer. The advantage of
residing, for a time both of us, at Burlington, a locality so well known for
the wealth of its crinoidal remains, gave us excellent opportunities to study
the Crinoids in all f-tages of preservation, and being in the field ourselves, we
could pick up such material as would help us in the study of minute details.

Since the publication of our first paper on the Crinoids, it has been our
aim to direct our special attention to studying the morphology of the vari-
ous groups as they appeared to us, with a view to future classification, and
to revise the work of the previous writers. The various classifications which
had been proposed were not based upon strictly morphological principles, and
in many cases widely distinct forms were placed together in the same group.

It early became evident to us that we could not hope to gain a correct
understanding of the fossil forms except by studying their living represen-
tatives. The publication of Carpenter's two Challenger Reports, and De
Loriol's important Monograph on the Mesozoic and later Crinoids of France,
opened to the working paiasontologist a new field of research, and enabled
him to study the relations between palaeozoic and neozoic Crinoids, which
had been altogether misunderstood. It had been the general opinion, ever
since the time of Johannes Miiller, that all paleozoic forms were widely
distinct from the later ones, a view also held by us until 1890.

Before the publication of the first Challenger Report, the attention of
palaeontologists had been directed almost exclusively to the structure of the
dorsal or abactinal side of the calyx; that of the ventral side had been very
much neglected, and scarcely any attempt had been made to homologize the

INTRODUCTION.

plates of the tegmen in the different groups. The first attempt in this
direction wns made by Wachsmuth in 1877, and the subject was taken up
again in our Revision of 1879. Dr. P. Herbert Carpenter discussed the
question more elaborately in 1884, when it became manifest that our views
differed radically upon several important points, and especially as to the
identification of the oral plates. The progress of our studies on this and
other questions was published from time to time in the Revision, and in
short papers. This was done for the double purpose of making known the
results of our own studies, and of stimulating inquiry by others upon points
that were still obscure.

Whatever may he the merits or demerits of the Revision — and that the
latter are many and serious none are better aware than we — it accom-
plished one of its purposes. It induced research and provoked discussion
upon new lines and with an activity unprecedented in this field. The
contributions to the knowledge of the subject, resulting directly from these
controversies, have been of incalculable value to us, and none the less so
because some of our own theories have been from time to time exploded.
As the most important result, it has now become clear that the Crinoids
were most intimately connected from the Silurian down to the present
time, and that only the Camerata — a highly specialized type — became
extinct at the close of the Carboniferous. It was not until this fact was
realized that the way was opened to a better understanding of the whole
Crinoid group, in which, as so often found in Nature, the simpler forms
persisted, and. led down to present types. Although it seems jolain enough
now, it was only by slow steps, and after long and patient research, that
this result was reached.

After a large amount of preliminary work had been done, we proceeded
to prepare for publication in permanent form such part of it as we could
reasonably hope to finish, and to that end we began the preporation of the
illustrations in 1887. The work has grown upon our hands to such an
extent that we found it necessary to limit it to the Camerata, the largest
and most remarkable group among Palosozoic Crinoids. Thus limited, we
could hope to give a reasonably full account of this group, and in connec-
tion with discussion of the morphological and systematic relations of the
other groups, to give some accoimt of the Crinoids generally.

The most of the drawings were made under our personal supervision in
our Museum at Burlington ; a few were made in Washington. Thirty-five

"m^

INTRODUCTION.

of the jiliites were drawn by Dr. Cliarles R. Keyes, tlio present State geolo-
gist of Missouri ; thirty-three by Mr. A. M. Westergren, so well known for
his drawings for Lovon'a great work on the Echinoids ; the reniainin"-
twelve by Mr. John R. Ridgway, artist for the United States Geological
Survey. The execution of the plates occupied about six years, and we
avail ourselves of this opportunity to express our thanks to all of these
gentlemen for the fidelity and earnestness with which they performed
their work.

When the work began to assume a definite shape, Mr. A. Agassiz, on
being made acquainted with the extent to which it had progressed, kindly
offered to undertake its publication as a part of the Memoirs of the Museum
of Comparative Zoology at Harvard College. No words of thanks would
at all express our sense of the obligation under which this has laid us, not
merely for the facility of publication through so desirable a medium, but
for the mark of appreciation whicli this offer implies. If the work shall be
found sufficiently useful to science to merit, even in a small degree, the
indorsement thus given, we shall deem it the best return we can make.

During the studies that led up to this Monograph, we enjoyed the privi-
lege of continued communication with our lamented friend, P. Herbert
Carpenter, up to the time of his decease. We had some energetic con-
troversies in print, and a far greater number in private correspondence that
never saw the light. To his incisive and suggestive mind is due the over-
throw of more than one promising but untenable theory ; and we take a
melancholy pleasure in recording here our appreciation of his high attain-
ments, and our sense of the great loss which Science has suffered through
his untimely death.

It has been our purpose to give descriptions of all American species of
the Camerata known up to this date, and those that coidd be recognized
have been described anew, with the aids derived from the material brouo-ht
to light since the original descriptions were made. Many of the species
wen defined from very imperfect specimens, and often without illustrations.
In the latter cases we have, when practicable, figured the typo specimen,
and when necessary and possible have given figures of additional specimens.

During the preparation of the work we have had access to most of the
type specimens in the United States and Canada, which were placed in our
hands for comparison, study, and illustration. A few only of Prof. Hall's
types in the New York State Cabinet of Natural History at Albany, and
some of S. A. Miller's later species, we were unable to procure.

4 INTRODUCTION.

Not the least of the pleasure we find in bringing our work to a conclusion,
is the opportunity it affords us of acknowledging our obligations to the men
of science and collectors of America, for their liberality and personal con-
fidence shown to us, by placing in our hands — often for indefinite periods
— original, unique, and priceless collections, without the use of which this
work would have been impossible. It would be difficult to express in fitting '
terms of acknowledgment the full measure of our indebtedness to them, and
we can only venture the hope that they may find in the work itself some
small return for the valuable contributions they have made toward it.

To Mr. Agassiz we owe a lasting debt of gratitude: first of all for hia
personal encouragement and valuable counsel, and next for the use of the
magnificent collection of the Museum of Comparative Zoology. This has
been placed at our disposal without restriction, not only for examination at
Cambridge, but for removal to Burlington of all specimens we desired, with
liberty to use them as if they were our own. Only those who are acquainted
with the character and value of this unrivalled collection can appreciate our
obligation for such a use of it. It contains the original collection of De
Koninck, of the Belgian Carboniferous Crinoids, and the Schultze collection
from the Devonian of the Eifel, — by far the finest collections that have
ever been made of the rare Crinoids of those interesting localities. There
are also the collections made by Hon. B. J. Hall, Prof. W. H. Barris, and
the original collection of Wachsmuth, all from the Burlington limestone,
which include the types of a large number of the species described by Hall,
White, and Meek and Worthen. In addition to these is the fine collection
made by C. B. Dyer, from the Hudson River group, of Cincinnati, con-
taining many typos of species described by Meek in the Ohio report, besides
most excellent material from Waldron, Crawfordsville, and other celebrated
localities of the West ; also the Walcott collection from New York.

A full account of the various collections made use of by us would
exceed the limits of a preface, but we cannot refrain from making par-
ticular mention of some of them : —

The collections in the American Museum of Natural History at New
York, containing many of the type specimens of the New York Palaeonto-
logical Reports, have been at all times accessible to us through the courtesy
of Prof. R. P. Whitfield, who has been prompt to send us such specimens as
we needed for illustration or comparison, and to give us any desired infor-
mation obtainable from the extensive material under his charge.

r mii'ifciii

mmm^

INTRODUCTION.

During the lifetime of Prof. Worthen, the eminent Director of tiie
Illinois Geological Survey, and afterwards under the administration of his
accomplished successor, Dr. Josua Lindahl, we enjoyed the privilege of
unrestricted facilities in ihe use of the type and other specimens in the
State Museum of Natural History at Springfield. The private collection
of Worthen, containing a large number of tlie types of the earlier species
described in Hall's Iowa Reports, was packed up and inaccessible wiiilo he
held the position of State Geologist ; but after his death, when the col-
lection was acquired by the State of Illinois and incorporated in the State
Museum, we were permitted through the courtesy of Dr. Linddil to
examine it, and were given full use of the valuable type specimens. As
a mark of our personal esteem, and in justice to the memory of this
pioneer collector and geologist, we have inserted the name of Worthen in
the notation of such of his type specimens as are now in the State Collection.
These types are of great value, as they are the only types of the early Bur-
lington and Keokuk species still in existence, so far as we know, with the
exception of a few in the Shumard collection. We have been unable to
obtain any information as to the types of Owen and Shumard's descriptions
in the Report for Iowa, Wisconsin, and Minnesota, in 1852, — the first Sub-
carboniferous Crinoids described from the West. A considerable pnrc of the
collections made during the first Iowa Geological Survey are said to have
been destroyed by fire, either at Burlington or Keokuk, and it is supposed
that a number of type specimens were lost in this way. McChesney's types
were all lost in the great Chicago fire.

The collections in the Canada Survey Museum at Ottawa, containing
the typos of all of E. Billings's Lower Silurian species, and the later ones of
Whiteavcs, have been freely open to us under the authority of S5l' Alfred
Selwyn, and through the unremitting courtesy of Prof. J. F. Whiteaves.

Through the attention of Dr. C. A. White and Prof. C. D. Walcott, we
obtained the use of the types of some of Meek's descriptions in the National
Museum at Washington.

Prof S. H. Williams of Ithaca, New York, had the goodness to furnish
us for examination the types of species described by him, from the •CTuseum
of Cornell University, and some of the types from the Colonel Jewett
collection.

Through Prof A. H. Winchell we had the use of the specimens in the
collection made by Dr. White, now in the University Museum at Ann Arbor,
containing the types of a number of well known Subcarboniferous species.

INXUODUCTION.

To Dr. G. Ilainbiich of St. Louis \vc owe the facility of examining the
type specimens in the Shunuird collodion at the Washington University.

We are under special obligations to Prof. Borden, of Borden Institute at
New Providence, Indiana, for the opportunity of e.xninining the original
collection of Dr. Knapp, of Louisville, from the now exhausted Bear Grass
locality near Louisville, containing some of the types of species described by
Lyon, Shumard, and Yandell, which now form a part of the Museum of the
Borden Institute.

To Prof. S. Calvin we are indebted for the loan of fine specimens from
the Hamilton of Iowa and New York, from which we made descriptions of
several species.

Our thanks are also due to Prof. W. H. Barris, of Davenport, la., who
gave us the use of his type specimens and other valuable material from
the Hamilton group of Iowa and Michigan, which were under his charge in
the Museum of the Davenport Academy of Science.

We also avail ourselves of this opportunity of expressing our high appre-
ciation of the favors extended to us by Dr. G. LindstrUm, of the National
Museum of Sweden at Stockholm, in which are deposited the magnificent
collections of Crinoids from the L'pper Silurian of Gotland that formed the
basis of Angolin's descriptions. Not only has he at all times allowed us the
privilege of having special drawings made from unique specimens in
the Museum, but on one occasion, on learning of the difliculty under which
we labored from want of adequate material to study the genus Crotalocrinus,
he sent us, without solicitation, a series of specimens, including some of
Angelin's originals, with liberty to retain them as long as might be necessary
for the examination we desired to make.

We have also to acknowledge our indebtedness to Mr. Walter R. Billings,
of Ottawa, Canada, for the loan of types of Trenton species in his own col-
lection, and also for his good offices in securing for our use the collections
of Messrs. Stewart and I. F. Sowter. Besides this, Mr. Billings has from
time to time furnished us valuable notes in relation to many rare and inter-
esting forms, often illustrated by exquisite drawings from his own hand.
We extend our thanks to Mr. John Stewart and Mr. I. F. Sowte; , of Ottawa,
Canada, for the use of their specimens, — Mr. Stewart having at one time
sent us his whole collection for study.

To the owners of private collections in the United States our obligations
are so numerous and varied that we cannot attempt to express in proper
terms of appreciation our indebtedness to each one.

INTRODUCTION.

It is especially (lifFiciilt for us to express our obligations to Mr. Victor
VV. Lyoii, of Jcfl'ursoiiviilo, Iml., who with the utmost liberality placed his
own collection at our disposal, and also that of his father, the late Major
Sidney S. Lyon, through which wo secured tho use of all the types of tho
species described by Major F.yon himself, and by Lyon and Cassodiiy.

Mr. Lisbon A. Cox, of Keokuk, la., gave us acciss to his extensive
and unique collection from the Keokuk limestone, containing tho types of a
largo number of species described by Worthen in Vol. VII. of the Illinois
Reports.

Mrs. Yandell, of Louisville, Kentucky, has sent us for examination some
rare types in the collection of tho lato Dr. L. P. Yandell. We tender our
special thanks to this venerable lady for the efforts she made to serve us.

To the natui-alists and collectors of Cincinnati and vicinity we are
indebted for great facilities in studying the crinoidal fauna of the Lower
Silurian of that region. Mr. I. II. Harris, of Waynesville, Ohio, placed at
our disposal the species of his maguilicent collection of Hudson River Cri-
noids. Mr. S. A. Miller favored us with the loan of his valuable types of
Lower Silurian species. Mr. E. 0. Ulrich, of Newport, Ky., has sent us for
examination the types of his species, and besides other instructive speci-
mens. He also used his influence in our behalf with Messrs. Oeh and
Vaupel, who placed some of tlieir finest specimens in our hands.

Dr. E. N. S. Ringueberg, of Lockport, N. Y., has sent us the types of
his species of the Niagara group of Western New York, with liberty to use
them as we might find desirable.

To Prof. J. M. Clarke, of Albany, N. Y., we are indebted for the use
of valuable type specimens from the Hamilton group of New York, then in
his private collection, but since passed into the New York State Cabinet.

Mr. Thomas A. Greene, of Milwaukee, Wis., placed in our hands a
large collection of natural casts from the Niagara group, including types of
the Waukegan species ; and Mr. W. C. Egan, of Chicago, a similar collection
from near Chicago, containing the types of the species described from that
locality.

Mr. F. A. Sampson, of Sedalia, Mo., gave us the use of his collection,
containing the types of a large number of species described by S. A. Miller
in the Missouri and Indiana Reports ; and Prof. R. R. Rowley, of Louisiana,
Mo., furnished us the types of liis species.

We are also indebted for the use of specimens and friendly acts in vari-

8 INTRODUCTIOX.

ous ways to Mr. Asa S. Tiffany, of Davenport, Dr. C. C. Wnshbiirn, of Wal-
(Iron, Ind., Dr. Mosua Elrod, of IIiirtHvillo, Inil, Rov. II. Ilerzor, of Hercu,
Ohio, l{ev. John Davis, of Ijouisiana, Mo., Mr. D. II. Todd, of Kannas City,
Mo., Mr. G. M. Nickels, of Sparta, 111., Mr. E. Brown, of Bi'lfaMt, N. Y., and
others.

To Dr. Horace O. Griffith, formerly of Burlington, now of Philadclpliin,
wo express our grateful acknowledgments for his intelligent and unremitting
efforts to aid us in the pro.secution of thiswork, and for his steadfast devo-
tion to our interests manifested upon every occasion.

We also bear in kindly remembrance our former townsman, Mr. James
Love, whose fine collection was always at our disposal, and which, together
with one made by Mr. J. W. Giles, afterwards passed into our hands.

Dr. Charles R. Keyes has at all times exhibited a lively interest in the
progress of our work, and we owe to him not only the procurement of some
valuable specimens, but other friendly ofliees.

Nor do we forget our good friend, Orestes St. John, whose keen eye and
rare juilgment, and no less his skilful pencil, have always been at our ser-
vice. We have from him some unsurpas,sed structural drawings, and he
presented us several unique Crinoids from the Coal Measures of Kansas.

Our thanks are due to Mr. Wm. F. E. Gurley, of Danville, III, for the
use of specimens from Waldron, and to Mr. A. C. Benedict, of Indianapolis,
for the use of specimens obtained by him at St. Paul, Ind.

In addition to the facilities above mentioned, we have had during the
preparation of this work our own collection, which contains authentic speci-
mens of nine-tenths of the species of Crinoids described from the United
States, and two-thirds of all the European species. From many of the typical
localities we have been able to obtain, either by purchase of local collections,
or by personal exertions, largo series of specimens, by means of which it has
been possible to study m many cases, and among different genera, the indi-
vidual variation existing in the limits of a species, and the modifications due
to growth.

In looking over the descriptions it will probably surprise some of the

authors to find so many of their species placed in the synonym lists, but

we were obliged to do so after careful study and comparison with authentic

specimens.

CHARLES WACHSMUTH.

FRANK SPRINGER,
BcRLiNOTON, Iowa, May 1, 1894.

Received at Cambridge, September 1, 1894.

ALEXANDER AOASSIZ.

^.'

'nm^, "PWiHw , *^HP''

TABLE OF CONTENTS.

INTRODUCTOUY PART.

Pahe

Inthodcctiom 1-10

IIhtuuical 11-31

TEHMiNOLOor 32-37

MUIU'IIOLOGICAL I'AHT.

Primauy and Supplementary Plates 88

TiieI'lates of the AiiAtTiNAL System 38-88

The Stem and its Appcndagos . 38-,'j2

Dasols niul Iiifrabasuls .... M-'S

The UaiUals 08-73

The Arms and Piimkn .... 73-88
The Plates of the Actinal System 88-101

The Orals 88-89

Mouth and Ambulacra 90

The Supplementary Plates . . . l(i.5
The distrlbutiou of the Plates and
IhcU' relations to the diirercnt

groups 105-123

The Anal Plates and the Anna . 121-1.'!9
Internal Cavity of the Calvx 110-112
Tlie Clianil)ered Organ and the

Axial Canals 140

Tlie Convoluted Organ 113

SYSTEMATIC PART.

Classification 141-172

Definition of the Cr'noidea and their

Primary Subdivisions . . . . 1C9
Analysis of the Families .... 170
Geological and Geograi)hical Distri-
bution of the Camerata . . . 172
Descriptive.

Reteocrinidae 173-187

Analysis of tlio Genera 173

Geological and Geographical Dis-
tribution 173

Reteocrinus 170

Xenocrinus 182

Tanaocrinus 185

Thysanocriniiiae 188-214

Analysis of the Genera 188

Geological and Geographical Distri-
bution 188

Tliysanocrinus 190

Ptychocrinus 197

Hyptiocrinus 200

Idiocrinus 202

Lampterocrinus 207

Siphonocrinua 209

Rhodocrinidae 215-263

Analysis of the Genera 215

Geological and Geographical Distri-
bution 216

Rhodocrinus 218

Gilbcrtsocrinus 233

Thylacocrinus 248

Diabolocrinus 249

Archa->ocrinu8 263

lihaphanocrinus 258

Lyriocrinus 201

Melochinidae 264-329

Analysis of the Genera .... 204
Geological and Geographical Distri-
bution 265

Melocriuites 267

Glyptocrinus 267

Periglyptocrinus 277

Stclidiocrinus 279

Mariacrinus 281

Macrostylocrinus 285

Melocrinus 292

Dolatocrinites 304

Technocrinus 304

Allocrinus 306

Centrocrinus 308

Dolatocrinus 310

Stereocrinus 324

Iladrocrinus 327

Calvptocrinidae 330-359

Analysis of the Genera 330

Geological and Geographical Distri-
bution 330

Eucalyptocrinus 332

CaUicrinus 353

T II E

CRLVOIDEA vJAMEUATA OF ^'011111 AMERICA.

INTRODUCTORV TART.

I. lll.STOUICAL.

The fifHt roforonco to FohhII CriiioidH, nccording to Do Koninck, 'vna
miulo by Aj^ricola in tho second half of tho Hixtoentli century. lie distin-
l^uislied between Tmc/ii'lcs, Eiilrochus, and Encnnua. The former name ho
applied to all detached Htem-joints ; Enfroc/tiis to a series of joints, and
Encnnns to tho calyx of Eiicn'mis liUifnriiih, at tlmt time the only Crinoid
in which a crown had been found in connection with tho stem. As early
as tho seventeenth and eighteenth centuries the crinoidal remains received
tho attention of a large number of writers, some of whom regarded them as
plants, others as animals.

Rosinus, who lived at tho beginning of tho eighteenth century, was the
first writer to show that tho Crinoidv were not plants, as before then gene-
rally supposed, but wore closely related to tho Asterids, and especially to
tlie group which afterwards received the name Euryale. He also supposed
that tho Trochites and Entrochites were parts of Encrinus, and not inde-
pendent bodies.

An important advance in the knowledge of the Crinoids was made by
Guettard,* who described the first recent Stalked Crinoid that ever came to
Europe. lie gave this species, which was afterwards known as Pentacn'niis
cnpiit-mcdiisce Lamk., the popular name " Palmier marin," and took it to be
the type of all fossil Crinoids with pentagonal stem, as opposed to those
with a round stem, of which he thought the living type had not been dis-
covered. He gave a moderately fair description of its structure ; but added

• M^moirc siir les Encrinitcs et les pifcrrcs dtoili'es, duns leqiiel on trnitera aussi dcs Entroques. (Miiiii.
de I'Acad. Roy. Soo. do Paris, 1755 (published 1761), pp. 224-318.

THE CRINOIDEA CAMERATA OF NOBTH AMERICA.

I \

little as to the systematic position of the Crinoids generally, stating, how-
e\ , that they were neitiier Polyps nor Starfishes.

Linnd, throughout all the editions of his '•Systema Naturae," placed
the Crinoids among the corals. Bluincnbach * has the credit of having been
the first writer who ranked them with the Asteroids and Ophiurids among the
order " Vermes crustacei," which corresponds approximately to our pres-
ent Echinoderms. Lamarck, in the first edition of his " Systeme des Ani-
maux sans vertobres," published in 1801, ranged them among the "Polypes
a rayons coralligenes," along with Gorgonia, Umbellula, and Pennatula; but
he afterwards modified this opinion, and in 1812 t referred the Crinoids to
the '• Polypes flottants," which he arranged next to the Kadiata. In 1810 J
he placed the Encrinites (Stalked Crinoids) among the Polyps, but the
Comatulae (Free-floaters) among the Echinoderms. Schweigger § directed
attention to the close resemblance that he found to exist between the arm
structure of stalked Crinoids and Comatuloe, and he considered the two
forms to be closely related. Cuvier in 1817, || and again in 1830,]f placed
the Crinoids among the Echinoderms.

The name "Crinoidea," with the rank of a family, was proposed in 1821
by J. S. Miller, for the lily-shaped, radiate animals which theretofore had
been known as Encrinites and Pentacrinites. He restricted the group to the
Brachiate forms, and to those provided with a stem, as appears by the follow-
ing definition:** "An animal with a round, oval or angular column, com-
posed of numerous articulating joints forming a cup-like body containing
the viscera, from whose upper rim proceed five articulated fingers." This
description includes neither Blastoids nor Cystids, which were placed by
Miller's successors as subordinate groups imder the Crinoids. It also ex-
cludes the ComatuloB and the genus Marsujntcs, which have no stem, and
which probably for this reason were referred by him to the " Stelleridoe."
Among the latter ho recognized four divisions : " Comatula3, Euryale,
Ophiura, and Asteria," and he placed Marstijnics in the same group with
Euryale. Miller knew little of the structure of the Comatuloe, but enough

1S12.

• Ilaudbiich der Naturgescliiclite, 1780.

f Extrait du cours de ZoiJlogie du Museum d'histoire nnturelle sur les Animaux sans vertcbres, etc.
2.

t Ilis'oire naturclle des Animaux sans Vertcbres, etc., 1815-1822.

§ Ilaiii'b. der skeletlospu, uugosliederton Tliiere, Leipzig, 1820, p. 528.

II Le ni-gv". animal, 1817 (l''),Vol. IV., p. 12.

^ Op. eit. (Ed. of 1830.)

** A Natural History of the Crinoidea, Bristol, 1821, p. 7.

HISTORICAL.

to be struck by the rcseniblarico tlioy bear to the crown of rcuhvn'nm. and
bo pointed out that the pentagonal plate at the base of the subgjubose body
of the Coniatula) occupies the position of the first column joint of the
" Crinoidea."

Miller subdiviLled the Crinoidea into four groups: the Adticulata, to
which he referred the genera " Apiooiuitcs, Encrinilca and Pciihicriiii/cs ;" the
Semiautici:lata with " Po/criocrinl/ca;" the IxAirricuLATA wi\\i " Cfalhocri-
nilcs, Aclbiocriiuti's, Uhodocrinitcs, and Plal/jcrinilcs ; " and the Coaduxata with
" Eurjmhwriniles." His primary groups were based upon the mode of union
between the stem and calyx, and between the latter and the arms; his
genera upon the number and arrangement of the jilates in the dorsal cup.
Considering tliat in 1821 only about twenty-five species of Stalked Crinoids,
recent and fo.ssil, were known, and many of them only from fi'agmontary
ppecimens, we cannot help admiring the genius of Miller, who brought
order out of chaos, and laid the foundation of the present classification of
the Crinoidea. Ili.s genera have been generally accepted, and are now rec-
ognized as the types of well-marked families.

Miller introduced an elaborate terminology, but unfortunately did not
always apply his terms to the same parts. In some of his genera ho gave
the term " pelvis " to the proximal ring of the plates within the calyx, in
others to the plates of the ring al)ove. In Apiocriiins and Aclinocriiuia he
called the radials " first costals;" the succeeding ones "second costals," and
the first axillaries " scapidas." In P/iif//criiiii-s, however, and in Potcrlocvinvs
and C'/iif/ifcriiii's, the radials ai'e his sc.ipula;, and are followed by arm plates.
Pla'ijcrinus, according to Miller, has no costals at all ; but in the dicyclic
Cyathocrinus and Pufemciimis costals are said to be represented by the plates
of the interradial basal ring.

A year after the appearance of Miller's work, Schlotheim published the
first part of the Supplement to his Petrofactenkunde,* reproducing therein
Miller's figures together with his own, and adopting his generic and specific
names. A year later, however, in the second part of that work, he withdrew
Miller's generic names, and referred all Stalked Crinoids back to Eiwrinus and
Pentacrimts respectively.

Goldfuss in his great woi-kt adopted Miller's classification and termi-
nology. Cumberland t did not consider Miller's name " Crinoidea" appro-

* Naclitraso ziir rptiTfactoukunilo, 1^23-193.'? (2 Biiiulc, mil 37 Kupfci-Platteuj.
t Potrofricta Gormaniw, Diisselilnrf, lS2(i-1833.
% Udiquix couservatoe, Bristol, 1820.

i I

THE CRINOIDEA CAMEKATA OF NORTH AMERICA.

priate, as not a single Encriims or Pcntacrimis resembled in the smallest
degree a lily, either in stem, root, flower, or bud. Nor did he think it
absolutely pioved that they were anunals instead of coraliue sensitive
plants.

In 1825, Say * described three new species nnder the genus Pciitrcmk-s,
which he made the type of a now family of the Crinoidea, and proposed for
it the name Blastoidea. He also described the genus Carz/ocniiitcs, which he
took to be intermediate between Ci/ulhocnims and Adinocriims. In the same
year two additional species of Peiitrcndtes were described by G. B. Sowerby.

In the years following up to 1840, a number of new species of Crinoids
were described by Mantell (1822), Pander (1830), Steininger (1831, 1837,
and 1838), Goldfuss (1832 and 1838), Zenker (1833), Phillips (1835-183G),
F. A. Roemer (1836 and 1839), Heisinger (1837), Sedgwick and Murchison
(1837), D'Orbigny (1837), Miinstor (1838-1846), and others; but they added
little to the general knowledge of the Crinoids.

L. Agassiz, in his Prodrome d'une Monographic des Radiaires ou Echino-
dermes,t referred the Crinoids to the " order " Slclleiiilcs, together with the
" genera " Comalula and Marsvpilcs, which, as he stated, differ from the
Crinoids only in not having a stem.

J. V. Thompson, in 1836, discovered % that the small species, which he
had described in 1827 as Pentacrimis ciiropaus, loses its stem at a more
advanced stage of growth, and changes into a free-floating Comatula.
Thompson also discovered the ovaries along the pinnules.

Other important discoveries in relation to the anatomy and development
of recent Crinoids were made by Adams, Ileusinger, Savigny, Delle Chiaje,
Blainville, and Dujardin. D'Orbigny in 1839 described the remarkable
recent genus IIulopus,^ a Crinoid not attached by a jointed stem, but by the
lower end of the calyx.

In 1840 appeared the classical work of Johannes Mliller, "Uebor den
Bau des Pentacrinus caput-medusao," || which marked a new era in the history
of the Crinoidea, and threw a flood of light upon the whole group. Mliller
in this work discussed the relation between the Pentacrinites and Comatulas,
and pointed out the anatomical diflferences in the structure of Crinoids and

• Joura. Acad. Nat. Sci. Pl.ila., Vol. IV., pp. 292-200.

t Meinoircs dc li\ Sociule des ScieucL's Niitiiielk-.s de Ncufclmlol, 183,5, Tom. T, p. IfiS.

J Alcmoir on tlic Starfish of tlio gonus Comrifiifn (Ediuburgli New Tliilos. ,Tourii., Vol. 20, p. 295.

§ Wicgmaim's Arcliiv I'iir Natnrgcscliiclitp, I, p. 185, Taf. 5, Fi2;s. 2-7.

II Read before the Berlin Akadeniie dcr Wisscuschaftcn, April 30, 18iO.

HISTORICAL.

Asterids. He also introduced a more rational terminology for the plates of
the calyx, which is still used by Zoologists and Palaaontologists. He proposed
the name " Bamlia" for the pelvis jilates of Miller, and '' Iiiidiulia" for Mil-
ler's scapulaj and costals, including the first axillary. When the rays are
free above the first radial, the axillary supports the arms ; but when that
plate forms a part of the calyx, it is followed by the " DisticJialla," and these
by the " P«/iH«;7«." For the supplementary plates he introduced the terms
" Intcrnulmlui, Inlcrdhlkhalia and Interpubtttria."

MUller divided the Crinoids into three great groups: the " Cnnoidm Arii-
culata," the " Cnnoidca TesseUaia " and the " Crinoidca Custata," which he
defined, and of which he gave a list of the principal genera.

Of the Arikula/a, to which Miiller referred Pciitacrimis, Apiocrinus, Encrinm,
and the Comatula9, he said that the rays develop directly from the base of the
calyx, and the lower ray plates are united laterally by a skin, which is either
naked or paved with irregular plates ; that this skin is continued to the ven-
tral disk, closing the ventral side of calyx and arms ; and that the radials
consist of three successive plates, of which the first and second, and the
axillary and the first arm-joint, are united by muscles.

MUller's Tessellata combine Miller's " Scmiarticulata," and " Inarticu-
lata," and include the Blastoidea, Cystidoa and the Cretaceous genus Mur-
supitcs. The calyx is composed of 3, 4 or 5 basals, which are sometimes
separated from the radials by a ring of " parabasals." Between the radials
there may be •' interradials," and between the distichals and palmars, " in-
terdistichals," and " interpalmars." The "Scheitel" (ventral disk) covers
the whole ventral surface ; it is constructed of solid plates, united at their
edges.

The Tessellata were subdivided by Miiller into two groups : Crinoidea
tvith arms, and Crinoidea ivifhoid arms. To the former he referred all true
Crinoids and the Cystid genus Cari/omnns, forms having no separate anal
opening and no " Tentakelfurchen " (food grooves) upon the disk, and none
probably upon the arms. The armless Crinoids comprise the " Pentremites"
(Blastoidea) and " Sphaeronites " (Cystidea), forms with separate mouth
and anus.

MUller's classification, although a great advance upon that of Miller, was
not accepted by the French and English writers succeeding him ; but it was
revived later on by Ferd. Roemer and von Zittel.

In 1842 a classification was proposed by Thos. Austin and Thos. Austin

0' 5

THE CUIXOIDEA CAMEKATA OF NORTH AMERICA.

II. LinEUIA (Free-floaters).
Uiiathoerinoulea.
Astnicriiioiilca.
Comastella.

Jr.,* who uuule the Crinoidoa in the widest sense a cliiss of the Echinodor-
niata, to whicli they gave the name " Pinnastella." Among the hitter they
placed as orders : —

I. ClOXA ClSKTl (Stalked Criuoids).
Families : Apiooriiioidea,

rutoriocrinoidea.

Encrinoidea.

rentaorinoidca.

IFarsupiocrinoidea.

I'latyciinoidea.

Actiiiocrinoidea.

Dimerocrinoidea.

Only the Platycrinoidea and Poteriocrinoidoa t were defined.

To the former they referred the genera ; riahjcriims, Dic/wcrinns, IJcxa-
criiiiis, Cai-yocnims, and Cijuthocmms ; to the latter : Fo/criocnim, Si/mhutho-
criniis, Kiiracn'mis, and Fciitacrmis. Their Encrinoidea include : Encrinitcs,
Eucul/jptocmilcs,- Cupnsmcrinitcs, and Fiir//ocrm/cs ; their Marsupiocrinoidea :
Mursupiooimtes and Crotalocrinilrs ; the Actinocrinoidea : Actinocrinitcs, Bho-
doenniks, Mchcrinilcs and TdracriniUs. The Austins placed the Blastoidea
with the Sphaeroidocrinoidea, and the reriechinidic under the Cohnnnida.

D'Orbigny in 1852$ undertook to subdivide the Crinoids (including
Blastoids and Cystids) into twelve families, which contain most heterogene-
ous elements. For description he divided the plates of the calyx into
zones, without reference to their radial or interradial position.

The next classification Avas that of Ferd. Rocmer, who wrote in 1855, §
and divided the Crinoidea into three great groups: —

I. ActiiwUlra, or true Ciiiioids, having large, pinnule-bearing arms.

II. Cyst idea, Crinoids in which the arms are feebly developed or wanting, and mouth
and anus are separate.

III. lllanfoidca, Orinoids without arms, the soft parts of the animal enclosed within a
calyx, wUicli is closed from all sides, leaving only a few openings.

The Actinoidea embrace :
A. Tlie Astylida, Actinoidea, Crinoids without jointed column.

a. Attached hij thn lower face of the calyx.

Holopocrinidje and Cyathidiocrinidse.

b. Calyx free.

Astylocrinidoe, Marsupitidte, Saccocomids, and Comatulicla3.

• Ann. and JLig. NnN Hist., first scries, Vol. X., iip. 103 to 109.

t Recent anil Fossil Crinoid's. Tlios. Austin and Tlioniiis Austin, Jr , London, 1S13.

J Conrs elcincnt.airc do Paleontologic, II.

j Lctbaca gcoguoslica (Ausgabc HI.), 1535, pp. 210-285.

j*»,fc; .i ii^mim •

HISTORICAL.

B. Styliila, Crinoids with a jointed column.

a. The tegmeii formed of a shin.

PentacriuidoB, Apiocrinidoe, Eugeniacrinidte, Encrinidse, CupressocrinidtB, Cya-
thocrinidte.

b. The ventral surface covered by heavy plates, immovably united.

PoteriocrinidiB, Itliodocriuidte, I'latycriuidaj, Actiuoci'iuidoe, Melocriuidte,
Ctenocrinida?, Sagenocrinidoe, Antbocrinidie.
C. The arms imperfectly developed.
Haplocriuidre and Gastrocomida'.

Roomer's families are natural groups, except his Cyathocrinidae, among
which he united a number of widely different forms. But this is partly due
to Miller, who had included with Ci/uthocrinns forms which were afterwards
referred even to different orders. Eoemer, believing that Miller's typical
species, Ci/athocrimts planus was a Poteriocrinus, made his second species
Ci/athociinus tuherciilatiis, which Phillips in 1843 had made the type of
Tcuocrinus, the type of Ctjathocrhms.

Together with the Classification was published Roemer's classical memoir
on the Cystidea and Blastoidea, of which especially that of the latter fur-
nished most valuable additions to our knowledge of the morphology of that
group.

In 1845 appeared the Memoir of Leopold von Buch on the Cystidea. He
gives excellent descriptions of several genera, and places the group at equal
rank with the Blastoidea and Crinoidea.

De Koninck and Le Hon, in 1853,* described a number of new species
from the mountain limestone of Belgium, and proposed certain changes in
the terminology of the calyx plates. The proximal ring of plates he calls
" basals," whether the species is monocyclic or dicyclic ; those of the second
ring in dicyclic forms " sous-radiales." The radials comprise all plates up to
the first axillary; and the succeeding plates of the rays, when parts of the
calyx, arc " articles brachiaux," otherwise arm plates. The term " inter-
radialos " is applied only to the pistes of the four regular sides ; those of
the posterior side are " pieces anales."

Another classification was brought out by Pictet, in 1857,t who divided
the Crinoids into nine families. The first and ninth of his families contain
almost exclusively Neozoic forms. The former embraces the Comaiitlce and
MarsupUes, to which was added the Pala8ozoic Asf^locriniis {Agasskocrimis) ;

* Rcclierclies sur Ics Crinoides du Terrain Carbonifere de la Bclgique.

+ Traite de Puleoutologie, par F. J. Pictet, Paris, 1837, Tom. V., pp. 278-345.

I:?

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

'.]'

the latter fiunily, to wliicli lie applied the name " Pycnocrliiitloes," is divided
into four Tribus, — the " Eiigeniacrinions, Encriniens, Apiocriniens, and Pen-
tacriniens." His second and third families comprise '• Blastoides " and " C)s-
tidees ; " the remaining ones, the •' Tessellata" of Miiller.

It is somewhat curious that Pictet, while placing Cupressocrinus, Euca-
li/piocrinus, and Crutulocrinus each in a separate family, referred all the
other Palajozoic CrinoiJs to only two families, — the " Ilaplocrinides" and
" Cyathocrinidcs." Ilis Ilaplocrinides embrace Ilaplocrinus, Coccocriiius, Cera-
mocrinus, Mi/rtilocnnus, Epudocriitus, and Gaslcrocoma ; all the other Palasocri-
noidea were placed under the Cyathocrinidcs. It is difficult to understand
upon what ground Pictet's families were based. His " Polycrinides," with
Eucaljptocriims, have closer affinities with Mclomims and Dolatocnints than
these with Cz/athocriiuts ; while Cupressocrinus agrees closer with the Haplo-
crinides than many of the Cyathocrinidcs among themselves.

Pictet subdivided the Cyathocrinitns into four tribus, — the " Cj'atho-
criniens," the " Actinocriniens," the " Carpocriniens," and the " Phitycri-
niens," — of which the first are dicyclic, the last monocyclic; while the
Actinocriniens and Carpocriniens are in part monocyclic and in part dicyclic.
He did not discriminate between genera in which the lower brachials form
part of the calyx and tho.ee in which they are free, nor did he pay the least
attention to the presence or absence of anal plates.

The classification of Pictet, although not so satisfactory as that of Roemer,
was accepted by Dujardin .and Hupe.* The latter, however, changed the
sequence of the families, making the "Cystidees" the first family, and
placing the " Comatulides " last.

In America, up to 1858, little attention had been paid to the study of
Crinoids. Of the fourteen hundred American species that are now described,
oidy about .seventy were then defined. In 1843 and 1851, Iliill had de-
scribed a moderate number from the Silurian in the P.iloDontology of New
York, Vols. I. and II., and a few additional ones through the Regent's
Reports at Albany. Owen ami Shumard, in 1852, United States Geological
Report of Wisconsin, Iowa, and Minnesota, described nineteen species from
the Subcarboniferous of the Mis,sissippi Valley, mostly from the Burlington
group; and Shumard, in Swallow's Missouri Geological Report of 1855,
twelve species from the same horizon. Tiie few remaining species had been
described by Conrad, Roemer, Casseday, and Yandell and Shumard.

• Histoire Naturelle dcs Zoophytes Ecbiuodermes, i)ar M. F. Dujardiu et M. U. Hupe, Paris, 1862.

HISTORICAL.

About the year 1858 the interest of the American Palneoutologists wa.s
aroused by remarkable discoveries of Crinoids in the Southern and Western
States. Troost, at the meeting of the American Association for the Advance-
ment of Science, in 1850, reported the ac()uisition of eighty-si.\ new species,
with sixteen new genera, from the State of Tennessee.* This discovery, liow-
ever, was totally eclipsed by the wonderful finds in the Northwest, where, at
Burlington alone, upwards of three hundred species were obtained, which for
beauty and excellence of preservation surpassed anything that had ever been
seen before. This one locality furnished a greater number of species than
had been described from America and Europe together up to 1857 ; and
while before, with a few exceptions, only calices had been ol)tained, now
hundreds of specimens were found in wliich arms, stem, and occasionally
the root, were preserved. The collections which were made at that time
by Wachsmuth, Barris, Dr. Thieme, and Hon. B. J. Hall, of Burlington,
and which were afterwards secured by Prof. L. Agassiz for the Museum of
Comparative Zoology, give testimony to the energy and enthusiasm with
which collecting was carried on in those days. The same interest, often
mingled with jealousy, was manifested by the men of science, who, anxious
to publish the new forms, and fearing they might be preceded by competi-
tors, brought out preliminary descriptions to secure priority for their species.
These descriptions, in many cases, were so indefinite that the identification
of the species was almost impossible, and this created considerable annoyance
and labor to later writers.

About the same time other large deposits of Crinoids were discovered in
Indiana. Crawfordsville fin-nished upwards of thirty species, Waldron and
Hartsville nearly twenty. At the latter places large collections were made
by Dr. Moses N. Elrod and Dr. C. C. Washburn. At Louisville and sur-
rounding country a large number of new species were found by Lyon,
Yandell, and Dr. Knapp ; at Keokuk, Iowa, by Dr. Kellogg, who afterwards
discovered also the rich Crinoid bed at Richfield, Ohio. Still more success-
ful as a collector in the Keokuk rock was L. A. Cox, who found two local
deposits of finely preserved Crinoids, — one at Keokuk, the other at the
opposite side of the river, which produced nearly forty new species. Dr.
Roeminger discovered the Crinoid bed in the Hamilton group at Alpena,
Michigan ; Springer that of Lake Valley, New Mexico, in the Burlington

* These genera niul species were described by Troost in a monograph. Tlie manuscript was deposited
at the time of his death in the Smithsonian Institute, but was never pul)lislicd, and ho did not receive the
credit which is probably due to him.

THE CRINOIDEA CAMERATA OP NORTH AMERICA.

group. Among tlic pioneer collectors must bo mentioned also Mr. Anthony,
U. P. James, and C. B. Dyer, of Cincinnati ; I. II. Harris, of Waynesville ;
J. Kelly O'Neall, of Lebanon, Ohio; Thomas A. Greene, of Milwaukee;
W. C. Egan, of Chicago, — who all made large local collections which have
furnished many type specimens.

Within the last ten years three most remarkable finds were made in the
West : — the first at Le Grand, near Marshalltown, Iowa, in the Kinderhook
group ; the second on Indian Creek, ten miles from Crawfordsville, Indiana,
in the Keokuk group ; and the other in the Upper Coal-measures at Kansas
City. The Le Grand bed furnished about twenty-three new species, not
counting the Blastoids. Of the latter, two species of Orophocriiiiis are repre-
sented, and in quite a number of their specimens the stem and pinnules are
preserved. Most of the Crinoids have arms and stems, and some of them
roots. The crinoidal layer, which is but an inch or two thick, furnished
many excellent slabs. We have one in our cabinet about a yard in diam-
eter, on which ninety-five specimens are exposed, both sides of it being
thickly studded.

Tiie Indian Creek locality was discovered by the late Charles S. Beachler
while collecting for us. It proved to be a local deposit in the bed of tlie
creek, not over twenty feet in diameter, and covered over a foot deep by
water. Too much credit cannot be given to Mr. Beachler, who obtained
under the most trying circumstances several thousand specimens, repre-
sented by nearly forty species. The specimens in places were so plentiful
that more than half of tliem had to be sacrificed to save the others. The
preservation is excellent, and in some respects surpasses that of any other
locality.

The bed at Kansas City is in the heart of the city. It was di.scovered by
Sidney J. Hare in the excavation for a large building. Only seven species of
Crinoids were found, but they are of exquisite beauty, and being embedded
in a soft clay, are of most excellent preservation. Good collections were
made here by David H. Todd, Sidney J. Hare, S. A. Howe, and E. Butts.

Almost as fast as new discoveries were made the species were described,
and in 1865 the number of American Crinoids had increased to six hundred
species. In 1858 appeared the Iowa Report, Vol. I., by James Hall, in
which he described over ninety species of Crinoids, not counting the Blas-
toids, and in the following year, in a Supplement to that Report, .seventy-
four additional ones. In 1861 Hall issued a paper entitled " Description of

..- -m-tg i "^ ^-^

:^w>~«vwcw» ia i m wr »ia r.uwg^-- ; ■ '•i/mm'-^K .«'«P' •

HISTORICAL.

New Species of Crinoklea, Albany, 18G1," in which ho gnve on eighteen
pages preliminary notices of one hundred and eleven Hpeeies. A large num-
ber of these descriptions remain in that shape to this day, while some of the
species were redescribed by him in the Boston Journal of Natural History,
Vol. VII. In the Puhuontology of New -k, Vol. III., Hall described
twenty-six species from the Ilelderberg groups, — some of them, however,
from arm or stem fragments, — and from eighty to ninety additional ones
through the dill'ereut Annual Reports of the N\'w York State Museum.

A largo number of species were described by Meek and AVorthen,
and after Meek's death by Worthen ; they amount to two hundred and
seventy species, with ten new genera, all well illustrated. Another lot was
descrilied by Lyon and Casseda\', and by Lyon individually ; in all thirty-one
species, with six now genera. Dr. C. A. White described thirty-five species,
and made three new genera. In Canada, E. Billings described some forty
species from the Trenton and Hudson River groups, with seven new genera.
In later years the most prolific species-maker was S. A. Miller, who increased
the number of species quite considerably. Many of his species have proved
to be synonyms, and while some of his new genera will be accepted by
every writer, others will go into oblivion. Additional species were described
by Whitfield, Wetherby, Ulrich, Barris, S. II. Williams, Wiiiteaves, Ringue-
berg, Wachsmuth and Springer, Walter R. Billings, Keyes, Rowley and
Hare, and others.

The American Palasontologists followed the termuiology of De Koniuck,
aid their descriptions, as a rule, are concise and readily understood. But
few writers besides ourselves discussed morphological questions, and S. A.
Miller, Prof Chapman, and we, are the only ones who attempted to classify
the Crinoids.

Billings, like most of the earlier writers, believed that the opening in the
disk of Palaeozoic Crinoids represented mouth find anus combined.* He
pointed out that the grooves and galleries, passing out from the centre of
the disk at the inner floor, are connected with the ambulacral system, and
communicate through the arm openings with the arm grooves, but do not
enter the tegminal aperture, which he found to be interambulaeral. When
Billings took iip this question again in 1869,t presuming that the aperture
represented the mouth, he concluded that in the earlier Crinoids, in Blas-

• Geol. Surv. of Canada; Decade IV. pp. 14 to 17.

t Notes on the Structure of the Crinoidea, Cystidea and Blastoidea (Amer. Journ. of Sci. and Arts (2d
series), July, ISfig, and January and September, 1870.

V ;

THE CRINOIDEA t'AMEUATA OF NORTH AMERICA.

tuidd luul iimny C^'Mtuld, the iiiuuth wns di^tconiiuetcd from tlie niiibulacra;
and that in those Cystidn hi wliicli inoro than one opening is represented,
the lateral one is the mouth, and not tlie central one, as had been generally
supposed.

A difl'erent interpretation of the opening was given l»y Schultzo, Sir
Wyville Thomson, Dr. W. B. Carpenter, Dr. Lilti<en, Loven and Waclis-
muth, who maintained that the month of all Echinoderms was located in
the centre of radiation, and insisted that the intcrambulacral opening was
the anil-'. SehuUze * could not understand how a Crinoid with an interam-
bulaond mouth could be sufTiciently provided with food, even if the arms
were prciiensiie organs, v/hieh they were not. lie .stated that Billings's im-
portant discovery, that the ambulacra enter the mouth by the arm ojienings,
left but little doubt that the mouth of the older Crinoids was subtogminnl
and central ; that the food entered the body through the arm openings, and
was carried underneath the tegmen to a common oral centre. His views
were corroborated by Meek,t who saw Wachsmuth's famous specimen (PI.
v., fig. 10), and found the nnibulacral tubes intact beneath the tegmen.
These observations were confirmed by Wachsmuth,| who had discovered
additional specimens with the ambulacra preserved, and most instructive
natural casts, in which the course of the ambulacra is indicated by ridges
upon the surface.

In England, for a long time, very little attention was paid to the study
of fossil Crinoids, and many well known forms are undescribed to this day.
Among the earlier English writers were Mantell, Cumberland, Parkinson,
Phillips, McCoy, Sedgwick, and the Austins. Their descriptions in many
cases are so primitive that neither genera nor species can be identified.
They were followed by the writings of Rofe and Grenfell, and these ul
Dr. P. II. Carpenter and F. A. Bather, whose excellent work attracted the
attention of every earnest student of Crinoid.s, and opened a new era in the
history of paloeontological research. In France but little work was done
upon Pahvozoic Crinoids. Oehlert described a number of interesting De-
vonian forms, and among them several new genera. De Loriol, so well
known for his Monographs on the Crinoids of Switzerland and France,
directed his attention exclusively to Neozoic forms.

• Monogr. Ecliinod. Bill. Knlk., Wien, 1867, p. 7.

f Notes on some points in the Striieture and Habits of the Palteozoic Crinoidoa, by F. B. Meek and
A. H. Wortlien (Proe. Aead. Nat. Sci. Pliila., 1869, p. 323).
i Amer. Journ. Sci. and Arts, Vol. XIV., August, 1877.

HI8T01, L

In Gonimny tlio priiicipiil wiitcif* oi fowi'i Crin"' L^ were: GolilfiiHN,
MUllcr, tlio two KoeineiH, Miiiistcr, Sti'in gor, Siinfll)t -cr. Qiioii'lt'ilt, Boy-
rich, Scliiiltzo, V. Moyor, v. Zittel, FoIImari, Walthf^i Kutilsol Wiij(«)t>r,
Steininaiin, Ncuiiiiiyr, and Jaukt-I. Tlic Belgian Crinoidx w«re inscribed
hy do Koniiick, and hy Fraijiont ; tlioso of Iliissia by Kicliwal 'Mcwingk,
Volbortli, F. Sobinidt, and TnuitMcbold ; a few Indian HpoeiinciiM i.^. Wangt-iv
and those from Australia by Ethoridgo, Jr., and McCoy.

In tlio year 1879 appeared the first volume of von Zittcl's IIandi)uch der
Palicontologie, with a chapter on the Crinoids. IIo made the latter a class
of the Ecliinodorinata, with tiiroo orders : the Eneriinilihtt or Crinoidca
scmn sirido, the Blastoidea and Cystidoa. Tiio Eucrinoidoa wore divided
into three sidjorders : TesselUda, Articiilula, and Coslntu, in which ho followed
Miillor. Ilia Tessellata wore separated by him into twonty-six families,
which comprise all the PuliKozoic forms, and the Cretaceous genera Mursiijii/i's
and Uiiifucriiiiis ; the Articulata into seven families, all Mosozoic and recent
forms ; the Costata comprise only the Jurassic Sitcrocinmt.

The Tesscllnla were defined by him as having thin, immovable calyx
plates, united by suture with smooth faces; " intorradials" rigid; mouth
subtogminal and anus excentric. Among the families he discriminates
between forms in which the tegmon consists : —

A. Exclusively of five large orals, or in addition to them small covering
pieces closing mouth and food grooves. The orals forming a pyramid or a
so-called Consolidalions-AjijjaraL" Arms simple : Ilaphicrinidw, risocvinuhe, and
CiipressncfhudfP.

B. Togmcn composed of small plates ; the mouth closed by five orals,
which either are teguiinal, or placed underneath the tegmen ; tlio anus
excentric. Dorsal cup formed of three (rarely two) zones ; the base gen-
erally dicyclic. Arms strongly developed ; tlieir ambulacra covered by two
or throe pieces : Ilybocrinida; Cijuihocrimdw, Taxocriiiidce, Ichthi/ocriiiidce, Cro-
talncnnidce and C/ieirocriin'da:

C. Tegmen vcntricose or balloon-shapod, composed of numerous thin
pieces ; mouth subtegminal. Anal tube long and heavy, the anal opening
near the base. Arms strongly developed and pinnule-bearing : Hcicrocrmda',
PoteriooimdcB and MnrsvpUida:

D. Tegmen composed of heavy, frequently nodose plates ; the middle
portion covered by seven larger pieces. Mouth subtegminal, communicating
with the arms through plated tubes. Anus often extended into a long pro-

THE CRINOIDEA CAMEHATA OP NORTH AMERICA.

boHcis witli tlie opening at tlio upper ciul : Onxtirocomiiliv, PlKti/rriiiiifir,
Cai'i»)criiiiilu', liriarociiiitilie, Diim. irrinitliv, liuiruiuliocriiiidw, Aclinocriiiiihf,
i</i/i(liorriiiiiltf, Milocrinidiv, J't>/i/j>il/ulii; UintucriniJa, (Jtifiitociinidic nnil liho'
diicriuiilit.

K. Teginen bottlc-Mlinputl, nnnowcr ftt tlio top ; composed of Inrgo,
polygotml pliites, regularly nrraiiged. ArniH not exteniKd beyond tlio cidyx,
biML-riul ; placed between rib-like projectiouH, or occupying closed conipurt-
ments : Cii////>fi>crini(l(t,

Till' Arllciihlii were defined by Zittel ns follows : Plates of the dorsal cup
generally very heavy, the articular faces excavated or smooth. Base mono-
cyclic, and Ibrmed of five pieces ; exceptionally dicyclic. Tognien, as a
rule, composed of a sUin-Iiko pcrii-oine, rarely plated ; mouth and food
grooves exposed. The mouth central; nnus excentricj orals present or
absent. Plates of the dorsal cup perforated by axial canals, passing out
from the dorsal organ, ajid continued along the solid parts of the arni» to
the ends of the pinnules.

To the Artioilnlii ho refers the following families : the Encrinhlce, Eiii/nm-
criiiiilif, IJii/i>/>ii/iP, Plk'dtdcriinihc, A/iincriiinlii', Ptulacrinida' and CnDialiilldtf,

Examining tho characters upon which Zittel separated tl.o Tessellata
from the Articulata, it appears that not one of his distinctions holds good
throughout the families of either group. The " Taxocrinidn) " and " Ichth^o-
criniilif," which he refers to the Tessellata, have a more flexible disk than
•either tho Encrinidas or Apiocrinida), and even than many of the Penta-
crinidiv ; and, besides, have an open mouth and open food grooves. Tho
Poteriocrinid:u have a flexible disk, and well defined muscular articulations
between the radials and costals. Tho interbrachials of Giictlardhrinus and
Apiomniis roissj/aniis are as heavy and rigid ns those of any Acfiiiocriiiiis, and
tho plates of the dorsal cup in Eiipnchi/crhius and Erlsocrmts are perforated
by axiul canals, a character which was supposed to occur only among the
Articulata. Neither is it true that the Articulata are "rarely dicyclic";
the reverse would be more nearly correct, for most of them had small infra-
basnls in early life, which gradually fused with the stem. No doubt Zittel's
groups marked A and E form excellent divisions, but B, C, and D comprise
widely differing types, and some of their families include monocyclic and
dicyclic forms. As a whole, Zittel's cla.ssification marks a great advance
over those of his predecessors, and he is the first writer who gave a good
definition of the families, and who arranged them systematically.

HISTOUICAL.

In 1H70, n month or two iiftcr tlio uppi'mimco of von Zittt'l's IlMinltnicli,
wo piilili^licMl I'liit 1. of our l{t<vir*ion of the I'alii'ocriiioidL'ii, utiilinicin^' tliu
Iclitliyocriiiiiliu and C^utliociiiiitliu ; and in ISHl hut II., containing tliu
iS|)liiuroidocriniila<. In both parts wo gavo a lovii'w of tho genera then
known, which wero rudu.-<i;riheil and M^'^teinalically arriingcd. We al^^o gave
witli each genus a list of tlie Hpucie.s and their synonyms mo fur as then
known. No elTort was niiidu \>y lis to subdivide the tinee groups, hecau>e.
as wo thought, tlio knowK'dgo of fossil Crinoids had not been advanced
snllicicntly to justify it. Wo waited for tlie pnbhcation of tlio Challenger
Keport, which wo hoped would solvo certain important morphological
questions. It seemed to us that a revi-ion of tho genera, many of which
had been incorrectly, others insulhciently, defined, and tho arranging of
them systematically among a few largo natural groups, was prefeial)le to
n classification based npon nnrelialde data. Wo separated tho Crinoids into
Palivocrinoidea and Stoinatocrinoidea,* tho latter to include idl M<sozoic
and later lorms.

Tho name " I'alivocrinoidea" had lieen introduced by Waclisniuth in
1877 as a subdivision of tho Crinoidea.t to include those forms in which the
disk is roofed by a second integument, which he supposed Id exist in all
Paliuozoic Crinoids. IIo recognized among tho Palivocrinoidca three dif-
ferent plans : —

A. 'I'ho Ar/iii'iiruiiis plan : Tegmon rigid ; composed of heavy, rather
large, immovable plates, forming a free inch.

IJ. Tho Taxdcriiiiis i)hin : Tegmen llexible, consi ling of minute, movable,
plates.

C. Tho Cfiiillmrrlnus phin : Tegmen at tho four regular sides composed
of a largo interiaili.d plate, tho posterior side extended into a tube or sac ;
mouth and food grooves covered by small p'ates.

Tho diftVrentiation^ in tho tegmon ho tliought were accompanied by im-
portant modifications in the composition of the dorsal cup, and ho expressed
the opinion that the construction of the tegmen afforded excellent charac-
ters for subdivisions. Those divisions were actually made by ns in tho
Revision, Part III., and they form practically the foundation of our present
chissification, notwithstanding that our views respecting the tegmon itself
Imve since then undergone considoraljlo changes.

• Tu plnco of Stnmiitnoriiini(lpn we afterwards adopted Carpenter's profcral)le name " Ncoeriiuiidea."
t His paper "On tli- C inslruclioii of the Siiirihiil and its Value in Ciassilicatinn." — Anicr. Jour. Sei.
and Arts (3d series), Vul. XIV., September, 18;7.

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Among the questions discussed by us in Part II., the most perplexing
one was that respecting the orals. As these plates are developed among the
fir.'5( in the larva, it seemed to follow that they must be present also in the
Palaiocrinoidea ; but tiie dilficulty was to determine which of the various
plates in the summit represent them. The median portion of the tegmen
in most of those Crinoids is covered by from seven to ten asymmetrically
arranged, more or less prominent plates, consisting of a central one of larger
size, four otiiors nearly as large directed anteriorly, and five others placed
posteriorly. ^.Ve regarded the central plate as an element unknown among
the la^or Crinoids, which occurred only in forms with a closed mouth, and
that it actually covered the oral opening. The oraLs, we thought, were
represented by six plates : four large and two smaller ones, the two latter
jointly representing the posterior oral, broken up on account of anal plates.

Part 111. of our Revision appeared in 1885. It contains the genera which
had not been considered before ; and we also completely revised Parts I. and
II., making important changes in the classification. Tiie Paloeocrinoidea
were subdivided into three sub-orders : the Camekata, the Ix.vduxata, and
the AinicuLATA, which we distinguished by the mode of union between the
plates of tiie calyx, and the condition of the arms, whether free above the
radials, or partly incorporated int^o tiie cup. The origins of these groups
date back to a time of which we have no palneontological I'ecord, they
being already highly differentiated among the earliest known Crinoids.
We divided them into twenty-six families.

The Crinoidni Camcrata were separated into Reteocrinidae, Rhodocrinidoe,
Tliysanocrinidfc, Glyptasterida?, Mclocrinidaj, Actinocrinidie, PlatycrinidoD,
Hexacrinida), Eucalyptocrinidoe, Barrandeocrinidto, and Acrocrinidfo.

The Cn'nohh'a Ar/iciila/a were subdivided into Ichthyocrinida) and Cro-
talocrinidcB.

Tlie Cnnniilca Iiifidioiafa were subdivided into; — A. Criiioidm Lnniformia,
with Ilaplocrinidas, Cupressocrinido3, Gasterocomida?, and Stephanocrinidoc ;
B. Crinnidm Fidvhila, with ITybocrinidao, Heterocrinidoe, Anomalocrinidaj,
BelemnocrinidaL', Cyathocrinidae, Calceocrinida?, Catillocrinida?, Poteriocri-
nidoD, Encrinidfo, and Astylocrinidae.

Most important from a morphological point of view was the discovery
of a fixed law respecting the orientation of the stem, which enabled us to
tiscertain the presence ot mfmbasals in many species in which these plates
are hidden by the column. By means of this law we were led to the con-

HISTORICAL.

elusion that by far the majority of the NoocriiioiJea are built on the dicyclic
plan, and either have small infrabasals, or had tliem in their larval state.
We continued to u«e the term "vault" as opposed to disk, believing that
the tegmen of Pahvozoic Crinoids differed morphologically from tlie disk of
later ones. Respecting the oral question our views had undergone consid-
erable changes, owing to the discovery that the two smaller plates, which
we supposed represented together the posterior oral, are radially disposed
instead of interradially, and we inferred that the central plate alone repre-
sented the oral pyramid of other Crinoids, a view afterwards strongly con-
tested by Dr. P. II. Carpenter.

In 1884 Carpenter's Challenger Report on Stalked Crinoids came out,
and in 1888 that on Comatulo3. In the former the author discussed among
other things the morphological relations between Paleozoic and Mesozoic
forms, and replied to some points which we had brought out in the Revision.
With regard to the structure of the tegmen he argued that some Platycri-
nidte had a "vault" ; but that the ventral covering of others did not differ
essentially from the disk of the Neocrinoidea. He believed that the Pal-
aeozoic Crinoids differed essentially from the later ones by means of their
irregular syuuuetry, caused by the introduction of aniil plates ; and upon
this and other ground-, to which we allude in another place, he made the
Palnoozoic and later Crinoids independent orders. In his classification he
fell back upon Leuckart's almost forgotten name "Pelmatozoa," which he
made a branch of tlie Echinodermata, with Crinoidea, Blastoidea, and Cys-
tidea as classes, and tiie Palajocrinoidea and Neocrinoidea as orders. He
also discussed the oral question, adopting the view which we had brought
out in 1881, but abandoned in the following year. He assumed that the
so-called central plate represents the dorso-central at the abactinal side,
the six proximals (iiis orals) tlie basiils, and that the latter are homologous
with the genitals of the Urchins. In the second Challenger Report, that
on the Comatula}, we were criticised very severely for asserting that prob-
ably the Comatula3 had infrabasals in the larva, which were actually dis-
covered by Bury before the Report was published.

Among the many interesting papers written by Dr. P. II. Carpenter,
none attracted more attention than the one in which he discussed the rela-
tions of the basals in monocyclic and dicyclic Crinoids.* He proved that

383).

Oil the " Oral " ami Apical Systems of Echiuodcrms (Quart. Journ. of Microsc. Sci., 1878, pp. 351-

THE CKINOIDEA CAMERATA OF NORTH AMERICA.

- 1

the proximal ring of the latter represents an independent element, and that
their second ring of plates corresponds morphologically to the proximal one
m monocyclic forms. This is now accepted by almost every writer. Another
important contribution to the knowledge of Crinoids was made by a paper
on Allugecrinus* a Carboniferous genus, in which the ventral surface is cov-
ered completely by live oral plates, thus retaining persistently the structure
of tiio Aiih'don larva.

The progress in tlie knowledge of fossil Crinoids was paralleled by that
among recent ones, of wliicli a great number of new forms were obtained by
the dredging expeditions. Until about 18G0 we possessed of Stalked Cri-
noids only a few specimens of Pciihwnnus caput-iiicdnsa, and one or two of
Iloloptis Ihtivsoni ; but since then new discoveries followed in rapid succes-
sion. In 18G4, Sars described the genus li/ikocn'inis ; Jeffreys, in 1872, a
new species of Peiitacrimis from the Bay of Biscay ; de Pourtales, in 1874,
a second species of Rhi-ocrimis. The dredgings by the '• Blake " under the
supervision of A. Agassis in tiic Gulf of Mexico brought to ligiit the new
Comatulid genus Atclecriinm, and a large number of specimens of PcnUi-
criiius ; those of the "Albatross" in 1891, off the Galapagos Islands, the
remarkable genus Culdiiiocriinis. The largest results, however, were obtained
by the "Challenger" expedition, which produced tluee new genera of
Stalked Crinoids, and one of Comatulaj. Progress in morphology and em-
bryology in later years has been as rapid as the discovery of now species;
in proof of which we need only refer to the works of Allinan. Goette, Sars,
Greeff, Ludwig, Pourtales, Bell, Barrois, W. B. Carpenter. Wyville Thomson,
Perrier, Bury, P. II. Carpenter, Vogt and Yung, and A. Agassiz.

Tiie oral question was finally solved in 1888 t by our di overy of the
remarkable specimen of Taxocrlnm, which proved conclusively that in forms
with large plates around the oral centre, asymmetrically arranged, the orals
are repros-ented not by the central plate alone, as we had supposed, nor by
the four large and two smaller proximals, as claimed by Dr. (Carpenter, but
by the so-called central plate together with the foui large proximals ; the
disturbance in the arrangement of tlie plates being due to the introduction
of anal plates. It was further proved that in specimens in which the whole

* Oil Allagocrinns, tlio Rppresoiilntive of a new family, etc. By P. II. Cavpeiilcr and R. Ellicridgo, Jr.
(Ann. niid Mag. Nat. His., April, ISSl, pp. 2S1-297).

t Discovery nf llic Ventral SInictnre nf Taxncriniis and Ilaploeriniis, and Conseqnent Modifieatlous in
tlic Classifiealion nf llie Crinoidea ; by Charles Waclismuth and Frank Spring' v (Proceed. Acad. Nat Sci.
Pliila., ISSS, pp. s.^iz-aci).

HISTORICAL.

tegmen consists of five large pieces, as in Ilaplocriuits, etc., these plates are
ornls, and not siippleinentiiry pieces as we had supposed.

The logical consequences of these conclusions were taken up by us in
1890,* when we undertook to prove that the so-called vault of Paheozoic
Crinoids is not a structure siti (jciterh, but a highly differentiated disk ; that
their large, rather regularly arranged interbrachial and iuteraml)ulncral
plates represent morphologically the smaller irregular pieces between tlie
rays and ambulacra of later forms, and that the Paleozoic and Neozoic
Crinoids do not differ so e-isentially fronx one another as we had supposed.
It also appeared that neitlior the closure of mouth and food grooves, nor
the presence of anal plates, is a constant character among the older Cri-
noids, and we were compelled in 1888 to abandon the Pala^ocrinoidea and
Neocrinoidea as systematic groups.

That the two groups could not be upheld, was proved also by Neumayr,t
who claimed that none of the characters by which they had been separated
was persistent ; and he [jroposed in place of them a primary divif<ion based
upon the condition of the month and ambidacra, whether mbU'jiHindl or
siipndcgminal, viz. :

I. Hijpasoocrlno'uleii. JFouth, ambulacral vessels, anil Saumpliittclieii (the liittor if pres-
ent) beneath the tegnion.

1. Sjiliwroit/ocriiKiren. Cup mostly, tegmen always, construetoil of a largo number of

plates immovably connected among themselves. Generally several of the arm
plates incorpotiited into the calyx by means of interrailial pieces, Tegmen roof-
ing the whole ventral surface. Among its plates are readily distinguished a
central one, and four and two interradiul proximals. Anus either directly piercing
the tegmen, or pl.aced at the terminal end of a plated tube. (This group agrees
with our Camerata.)

2. JIdjilocrinacea. Cup and tegmen composed of a small number of immovable jiieces.

The former having but one radial, and no interradials except an anal. Tegmen
with a central plate. (Our Larvifonnia.)

3. Jf/tt/iyncrliiacca. Cup and tegmen composed of very numerous, somewhac movable

pieces; the former having two basal rings and more than one ordei- of radials.
(Our Ichthyocrinida'.)
II. Epascofrinoiilea. Ambulacra not covered by the tegmen; their furrows exposed or
closed by Satimpliittchen.
1. Ci/itlhocrlnacfa. I?ase generally dicyclic. Cup without interradials nt the four
regular sides. Tegmen, so far as known, composed of five orals, whieli sujiport at
their edges the ambulacra; the latter covered by Saumpliittchen. Anus within the
ventr.al sac. (Our Fistulata.)

• Pprisomlc rialcs of the Crinoids (Proceed. Acad. Nat. Sci. Pliila., October, 1S90, pp. .?t5-375).
t Dio Sliimme des Tiierreiclics, Wicn und Prng, 1889, pp. 438-lCO.

THE CRINOIDEA CAMEKATA OF XOKTII AMElilCA.

2. Pentiicrlnucea. Calyx with a well ilofiiicil basal ring; iiifrabasals wanting or rudi-
mentary. Ainbulacral furrows and mouth (in all of tlii'ni '.') exposed. Tegmen
pliable with movable Saunii>liiltelien, or witli five huge orals and without Saum-
pliittchen. (I'entaerinida', Apioorinidie, riieatocrinida.', Uourguetocrinida', Kiigenia-
crinidiL', Ilolopidie, and Comatulidie.)

Neuinnyr's primary divisions are partly based upon incorroct observation.
Among the three groiip.s which he refers to the llypascocriiioidea, the
Saumpliittchen are siibtegniinal only in the Ilaplocrinacea. In the remain-
ing groups they may be subti^gminal or exjiosed among .sjiccies of the
same genus. The Ichthyocrinacea even have an open mouth and open
food grooves. On the oral question he agreed with Carpenter, and took
the six proximals to be representatives of the orals.

Neumayr ranked the Crinoidea, Blastoidea, and Cystidea as independent
classes, and believed that the two former are derived from the C3stidea,
which to some extent combined the characters of the three groups.

Dr. Steinmann * adopted our classification of 1885, with Pakeocrinoidea
and Neocrinoidea as primary groups.

Two other classifications were proposed in America, — one by Prof.
E. J. Chapman, the other by S. A. Miller. The former t is to a large
extent hypothetical, being founded upon characters of which nothing, or
almost nothing, is known among Pakvozoic Crinoids. His classification is
based mainly upon the presence or absence of a canaliculation within the
calyx and arm plates for the occupation of axial cords. He recognizes
three leading divisions : —

1. EincdiiUata. Calyx plates and arm plates without internal canals.
II. Fis/iilata. Arm plates with donsal canal. Cal^x plates imperfoiate.
in. CaiHtUculiita. Calyx plates traver.-ed from the basals upwards by
delicate radiating canals. The arm plates canaliferous dorsally.

The classification of S. A. Miller J may perhnps facilitate elementary
studies, but has no value from a morphological point of view. In forming
his families he made the number of basals the most important character for
division, next the presence or absence of " subradials," and after this the
structure of the "azygoiis side and other parts." His classification is a
reminiscence of that of Angidin, § who divided the Swedish Crinoids into

• Elcmente der Pnltpoiitnloi^ie, Loipzip, ISSS.

t A Clnssificrttion of Crinoids, bv Professor E. J. riiapmnn, Toronto. ]882.
X Amcrioan Gi'olnsist. Vol. VI.. 1S90, pp. 275-2SC, and pp. 340-35?.
§ Iconogr. Crinoid. Suecitp, 1S7S.

'4!i

HISTORICAL.

Trlmern, Tetramera, Pontamein, and Polymura. The fallacy of this plan is
well shown if we consider that the smaller number of basals is simply the
result of anchylosis of two or more of the original live plates; and tliat in
many cases it brings together the most diverse forms, while forms which
naturally belong together are widely separated. We need only refer to
the highly differentiated Calceocrinidiu, of which some species have four
basals, and others but three. In the genus Plaljemnis the normal i.unnber
is three; but in many cases they are anchylosed into a solid disk, leaving
no trace of suture lines. Under Miller's classification many species, and
often individuals of the same species, would have to be referred to different
families.

The most important recent European writings on Palaeozoic Crinoids are
those of Mr. F. A. Bather of the British Museum, who has done much
valuable work in systematizing the terminology. His descriptive work has
been chiefly confined to the Fistulata of the Wenlock limestone of England,
and its equivalent in Sweden ; but we should like to see it extended to
include the Carboniferous Crinoids of England, of which careful study is
greatly needed. His admirable Monograph on the Crinoidea of Gotland,
Part I.,* arrived too late to be considered in this work as fully a.^ would be
desirable ; in it, however, he has rendered a great service to all students by
bringing order out of the confusion in which the splendid Swedish collec-
tions had become involved by reason of Angelin's fictitious illustrations and
restorations. We hope nothing will occur to prevent the completion of
his work.

* " The Criuoidca luatluiiata," with ten photograpliic jilutes, published by the Royal Swedish Academy
of Sciences.

II. TERMINOLOGY.

The following terminology niny be regnnletl as the result of a two years'
conesponlence with the late Dr. P. II. Carpenter, carried or with a view
to securing greater uniformity and preciision in the morphological nomen-
clature of the Crinoids; and we mutually agreed to adopt it in our future
writings. On some points, Dr. Carpenter defined his own position in a paper
whii'li ai)peared about a year before his death.*

Mr. F. A. Bather, in 1890, alsof agreed to accept this terminology with
very slight modifications, and applied it practically in his earlier descriptions
of British fossil Crinoids, but renounced it in 18U2,| and proposed in its
place a now one, which will be discu.ssed later on. Many of the terms which
are explained below are familiar to every studo^t of Crinoids ; but as some
of them have been used in dilYcrent senses by different authors, we include
them for the sake of completeness. A few of theni are new; others, though
used by foreign authors, have never been introduced in American Crinoid
literature. We believe that the terms are adapted equally well for the
description of recent and fossil Crinoids, ]»innulatc as well as non-pinnidate.
There are a few additional terms, not of such general application, which
will be found explained in their proper places.

The Crinoids, Blastoids and Cystids, -with perhaps a few exceptions,
differ from all other Echiuoderms in being at some stage of their life pro-
vided with a stem for attachment to other objects. This structure gives
rise to a difl'erenco in habit, l)y which they live upon the aboral side, instead
of creeping about mouth downward in search of food.

The skeleton or test of a Crinoid consists of the ftcm or column, and the
cro/fii. If the stem is provided with lateral appendages, these are called
cirri. Those of the distal end are the rmliciikir cirri, and form the root.
The stem is constructed of the stem joints, of which the larger, and all cirrus-

• "Oil some Points ill tlie Anatomical Nonicnpl;iturcof tlic Kcliiiiodcrms ; " Ann. and ^^ag. Nat lliji.,
1890 (July number).

+ Uritisli Fossil Crinoiils; ibid. (Apiil iniiiiboi), jip, 300 to H:iO.

J Sngijcsted Terms in Crinoid Moi'iibolngj- ; ibid. (January), pp. 51-C6

'-3h.

TERMINOLOGY.

bearing ones, constitute the nodal joints, and tliose interposed between them
the inlcrnudd ]omis. The term dorsocenlml is used for the enhirged terniiniil
joint of the stem, by whiclj the young Crinoid is attached to other objects;
and cenlrodorsid for the modified, cirrus-bearing top joint of the Conlatula^
us well as for the plate within the infrabasal ring of the JIarsupitidie. The
longitudinal canal, passing through the centre of the stem, is the axiid ciimd.
In speaking of the form of the stem, allusion is made to the transverse
section.

The crotvn consists of adi/x and arms ; the former encloses the visceral
cavity; the latter constitute tlie free appendages, passing off from, and con-
necting with the calyx.

The ctdi/x is composed of the dorsal cu}>, and the ventral did- or teamen, the
arm regions forming tlie line of demarkation between them. The dorsal
cup conforms in a general way to the apical or abactinal system of the
Echinoderms, the ventral disk to the oral or actinal sj'stem.

The dorsal cup, in its simpler form, is constructed of hasnls, infralasah,
when present, and radials ; to which must be added the amd plates, wJiich.
however, are not always represented. In the more complex form it includes
also some of the lower brachials, which have been incorporated into the
walls, either by lateral union among themselves, or by means of interradial
and interaxillary plates ; the last mentioned plates, in that case, also form-
ing part of the cup. All Crinoids belonging to the simpler form are dis-
tinguished as Crinoklca Inadunuia ; those of complex form, ivhcn the caf>/x is
rigid, as Crinoidca Camc-a/a, but when Jkxible, as Crinoidca Artiadata.

The base, or part next to the column, may be composed of one or two
rings of plates, which are distinguished as hasals and iii/rahasals. The basals
adjoin the radials and alternate witli them, being interradial in position.
The infrabasals, when present, are radially disposed below the basals. Cri-
noids in which the base consists of a single ring of plates are called mono-
cyclic ; those with two rings, dicijclic.

The radials consist of the first plate of each ray, and all plates beyond
this in radial succession are brachials; fixed brachials so far as they take
part in the calyx, /rcc brachials or arm pla/cs when they do not. In some of
the earlier Crinoids one or more of the radials are bi.sected transversely, in
which case the two parts are distinguished as stipcr-radials and iiifcr-nidials.

The arms may be simple or branching. When the divisions are of equal
siie, and rise to the same general height, they are regarded as parts of the

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

arms jjro/wr ; but when siimllcr niiJ shorter than tlie main arms, they nre
eiilled uniUels. It" there are small hiteral appentlayes, given off alternately
from opposite sides of the arms, they receive the name pinnules. The arms
are imiavmU when their joints extend through to both sides of the arm ;
bmri'al when they do not, but interlock from opposite sides.

The brachials succeeding the radials (the lirst axillary included), whether
free or fixed, are called coduls, or primary brachials ; tho.se of the second
order dislichuk, or sceoiiiliri/ brachials; those of a third order 2>nlmars ; and
all succeeding brachials, wiiether there are additional divisions in the ray
or not, receive the imxno posl-paliiiars. When in the description of a species
it is noces.sary to specify any of these plates, they are distinguished as
brachials of the fourth, fifth, or sixth order, and so on to the last bifiuvation.
We also find it convenient occasionally to refer to them as the plates be-
yond the fourth, fifth, or sixth axillary ; or, when free, as plates of the first,
second, or third division of the arms. The plates of the different orders,
according to their rank, are distinguished as first, second, or third costals,
distichals, palmars, etc., and the bifurcating plates as the (uilhirics of their
respective order.i. All these appellations, however, are not applied to the
divisions formed by the armlets and pinnules, although the plates which
support them are in fact axillary, and each armlet or pimiule is morpho-
logically the homologue of a whole dicliotom.

When two or more arm joints meet transversely by a rigid suture, and
only the upper onj is pinnule-bearing, those joints form a si/zi/ffi/, whether
the apposed faces are r.idiated, dotted, or smooth; the lower joint bearing
no pinnule is called the /////w^y^«/ joint, the upper one the finznaal.

T'e spaces between the rays and their subdivisions are filled by supple-
mentary plates. Those between the rays proper are designated by the
general term hitcrradink, whether they belong to the dorsal cup or to
the ventral disk. Those of the dorsal cup, which arc interposed between the
brachials, are distinguished as iuierhraclmls, and those of the ventral disk,
which lie between the ambulacrn, as intcramhnhcraU. Plates between the
radials at all five sides are only foimd in dicyclic Crinoids, but in most of
the PalcTOzoic Crinoids there are one or more such plates at the posterior
side — the .so-called amd plates.

The anal plates form the base of the anal structures, and consist of the
special or frst anal plate, which, when present, invariably rests upon the
truncated upper face of the posterior basal, and between two radials. Most

Ill

TEUMIXULOGY.

of the Camerata also linvo auxiliary nnul plates, which may be present even
wiieii the special anal is wanting; tiiey are interposed between the inter-
brachials, following the median line of the posterior area. Another plate,
the so-called " second anal plate " of American authors, which only occurs
in the Inadunata and Articulata, is now called the mdiuiml. It rests within
the re-entering angle of two adjoining basals to the right of the first anal
plate, and is the lower half of a bisected radial, whicii owXy in some genera
assumes anal functions.

Certain groups have interaxillary plates, which occupy the spoces within
the axil of the disticlmls and palmars ; the plates between the former are
the iiitenU4ii'Jutls ; those l)etwocn the latter the intcrpdlmars.

The ventral disk embraces the disk ambulacra, the mouth, and the anus.
It is formed by tlie omls, the anihtdacml and inlcmmhulucml plates. The
posterior side of the disk in certain forms of the Inadunata, to which wo
have given the name Luiduiiakt Fisluhda is extended upward into a large sac
or tube, which is called the vcntml sac or vcntml tiihe. This tube is frequently
perforated by pores or slits, which probably promoted respiration. Other
forms of that group do not have these pores through the sac, but have
a single, rather large, profusely perforated plate upon the disk proper, be-
tween the sac and the mouth, — the so-called iiiadrcjwri/c. The disk in most
of the Camerata has small rcspiralori/ pores or .«lits near the arm ba.se.s, pierc-
ing the sides of the plates. In recent Crinoids, ond probably in the Articu-
lata generally, in which the pores penetrate the body of the plates, the
perforated plates have received the name aii-amhtilacrals.

The anus is interradial in position ; its opening may be cither central,
subcentral, excentric or marginal ; placed at the distal end of a tube, or
opening directly through the disk.

The "amd" tube must not be confounded with the " ventral" tube of the
Fistulata, which often does not contain the anus, but when it does, the
opening is generally on the anterior side.

The mouth occupies the centre of radiation, and is tegminal or srditegminal.
If it is tegminal, the opening is surrounded either by the orals and the ends
of the ambulacra, or, when the orals are absent, by interambulacral plates,
which form a lip around it. H sultcgminol, it is completely closed, either by
the orals or interambulacral plates, which form a roof over it.

The ambulacra diverge from the mouth to the tips of the rays, following
the ventral furrows of arms and pinnules. When sub tegminal, they enter

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

CT^'.

the cftlyx by inonns of the amhulacnd or arm npenings at tlio upper cdgo of
the dorsal cup ; when toj^iuinul, they follow the surfiieo of the disk. They
contain the ftxiil-jroare, the Kinhiildeml vvusvlx, the oi'iiriun tube, and the (O'hil
ciiiiiil. The fofxf-ffnioi'c forms the upper passngo. It is followed in descending
Older by the siili/eii/nciilur canal, the (jciillal canal, and the u.rhil canal. The
axial canal contains the axial cords, which cominnnieato with the vhambvnd
ori/an at the dorso-central basin of the calyx. The axial canals, in most of
the Pala)ozoic Crinoids permanently, and in the Aiiledun larva temporarily,
are mere grooves at the bottom of the ventral furrow, but in the mature
recent Crinoid, and in a few Palieocrinoidea, are separated from the furrow
by a limestone partition.

The aiukdacral plates consist of the ud-andmlacral rr sidc-invccs, nnd the
corcrixg plates, or Samnpliittchen ; the former, when present, constitute the
outer, the latter the inner rows of the plates. The covering pieces form
a roof over the food grooves, and arc generally represented by two alternat-
ing rows of small, more or less regularly arranged plates, which in all
Crinoids are movable upon the arms and pinnules, but upon the disk only
in those in which the mouth is exposed. In some of the Cnmerata the
plates are so higidy differentiated, that they have been regarded as alto-
gether difTerent structures, and were called radial dome plates. We retain
this name as a conventional term for the large isolated plates of that group
to distinguish them conveniently from the ordinary covering pieces.

The orals consist of the five large interradial plates which surround the
mouth or cover it, aiul are either symmetrical or asymmetrical. They are
symmetrical when of nearly the same size nnd form ; asymmetrical when
the posterior plate is pushed in between the other four. In some species
they occnpy the entire ventral surface of the calyx ; in others, only a com-
paratively small space in the middle ; or they may be completely resorbed
in the mature individual.

The interamfi'lacral plates occupy the spoces between the ambulacra,
their main trunks as well as their branches. We also apply the term to the
platen covering the ambulacra, and to those encroaching upon them from the
sides, as in many species of the Camerata In which the disk ambulacra are
subtegminal or partly so.

The term jwrisomic plales is given to all plates which are originally devel-
oped from simple, cribiform films of limestone. They comprise the inter-
radials and interaxillaries, the anal.'*, and all ambulacral and interambulacral
plates.

■amvi-.i -|~~i" i | ii

TKKMINOLOr.Y.

Tlio pliitcs of a Crino'ul nro imitiMl cither hy suture or hy mu,-<cMilar
nrtieuliitioii. Tlie former may be a c/wc suture, a /w«(' xuturo, or au innliii-
Inm'ti. A close suture is neiuly or perfectly rigid ; the npposeil faces are flat,
ami may be Hinoolh or striated. In a loose suture the faces are more or loss
oonravo or excavated, lodging bundles of ligament, so as to give to the
plates a considcral)Ie amoiuit of mobility. An anchylosis is a niodilicd close
.suture, in which the lines of union have been obliterated by subseriuent
limestone deposit. In a. muscular articulation, the apposed faces are per-
forated, and provided with a transverse ridge, or a sort of ball-aiid-.soeket
joint.

The orientation is based upon the natural position of the Crinoid, /. p.,
the arms uppermost, viewing the specimen from the anal side. The anal
interradius will then be posterior, the radius o])posito to it anterior, and
right and left will correspond with the right and left of the observer. Next
to the anterior ray are the two antero-laternl rays,* and adjoining the anal
interradius the right and left posterior rny.s. Corresponding appellations are
applied to the interradial spaces, which consist of the two anterior, the two
antero-lateral, and the posterior or anal, interradii.

In illustrating the plate.? of the calyx, the dorsal view is figured with the
anal intciradius (7), and the ventral view with the anal side (hucii. Right and
left remain the same in both cases.

The tcrmi^ j>ri).ii)ii((l am] (lix/n/ m-c reckoned from the chambered organ, so
that the infrabasals and the top-atom-joint arc the proximal elements of
crown and stem respectively. In the crown, the outer surface of a plate
represents the dorsal side, its lower edge the proximal face, its upper edge
the distal face, and the faces at the sides are the lateral faces. In the stem,
however, the x/ipcr face is the proximal, and the lower one the distal.

• Those rnys nro called by Mr. Patlicr t)ic ri(,'lit ftiul left "anterior" rays. The term is ohjeclioiiahlc
because we have already the anterior ray proper.

MOUniOLOCJICAL PAKT.

riUMAIlY AND sriMTJlMllXTARY I'LATK.S.

Tin: iihites of the Crinoiils full initiimlly into two cntogorifM, viz., prlntun/
l)Iates, tiiiil nccKiiiltri/ ov mi/>j)liiiini/tin/ pIiitoH. TIr- priiimry plates nrc tlic fii'Mt
paitn tlovL'lopcil in tliu larva. Tliey are ifprcMoiitt'd in cvoiy group of tlio
cIuHH, iiud luulorgo comparatively few niotlificationH in geological time. The
Biippleniontary pieces appear in the growing Crinoiil, but arc nnroprcHenteil
:i: .xoiiie of the groups. Tiiey are interposed between tlio primory plates,
nnd help to increase the capacity of the visceral cavity. Tiiey are very im-
portant in point of classification, offering by their presence or al)sonco, their
position ami distribution in the caly.v, their arrangement and multiplication,
excellent criteria for natural divisions.

The primary plates may be subdivided into two classes : plates of the
abiictinal system, and plates of the actinal system. The former are developed
on the rigiit larval antimer, and include all plates connected with the cham-
bereil organ and the axial cord.s. The latter are developed on the left anti-
mer, and connnunicato with the mouth and the annular vessels surrounding
it. The abactinal plates are represented by the stem joints, the basals,
iiifrabasals, radials, and the plates forming the dorsal parts of arms nnd
pinnules ; the actinal plates by the orals and anibulacral plates to the ends
of the brachial appendages. The remaining plates will be treated by us as
supplementary pieces.

I. THE PLATES OF THE ABACTIXAL SYSTEM.

A. Hie Stan and t'fa Appcmhges.

The length of the stem in some Mcsozoic Crinolds must have been enor-
mous. Quenstedt traced that of a Jura.ssic PviUacriints to 70 feet without
reaching either end. This is in striking contrast to its length in Palaeozoic
forms. Among them the two longest stems observed by us have a length of

MoRi'iroLoorr.vTi paut.

nhoiit tlirco feet, — one, not <|uite complete, being tliiit of a liirgc MiylKlin'mim
/■Jniiiti, tlio other, wliieli in perfect, of a S/rnfniriiiiin irgnlls, two of tlic liirgcst
known Mpecii's. Tliiit seems to liiivo been iilioiit the miixiimim h'iij.Mli. ami
it iniiy 1)0 siiffly iisMerted thiit the Htem in the miijorily of the oMer (VimtiilH
wiiH not miieli over ii foot long. Homu Htems arc proporlioniilly wifh-r nt I In-
top, iiml taper all the way to tho root; others are larger at the ili«tiil enil
than at the proximal ; whilu Htill others are widest in the miilille.

The root is even more variable. Its form was I'vidently aci'oimiiodiiled
to the comlitions of the place of its attachment. When attached to a solid
sub.stanco, it wa.s flattened at the distal face, Hio radicular cirri sprending
out horizontally ; but when growing on an oo/y bottom, it gave oil' long
vertical and lateral branches, entering the mud.

The stem is either circular, elliptic, pentangular, Rtellnte, semiluuato, or
quadrangular, changing from angular to round on approaching the root. It is
composed of joints, which vary often ccjusiderably in size. Certain of these
joints, which have boon denominated " nodal " joint,s, are separated from each
other by intervals of dilTerent lengths, which are filled by internodal growth.
Tho nodal joints aro not only longer than the internodal ones, but also
wider, and, as a rule, increase in length downward. Their diameter i^
greatest in the upper part of tho steni, where in .some species of the Came-
rata it is often twice, and exceptionally three times, that of the internodal
joints. Tho projecting margins aro sometimes knife-like, the edges occa-
sionally crenulated, spinous, or nodose. Tho greater amount of length
wdiich characterizes these joints, however, does not extend to their full
thickness, but is more or less restricted to the projecting margins, the
miildlo part at both ends being depressed, so as to enclose wholly or in
part tho adjacent internodals.

In tho growing Crinoid, tho stem constantly increased in length by the
production of new joints, introduced either directly beneath the calyx, or at
some distance from it. The joints which aro formed at the proximal end of
the stem gradually developed into nodal joints, and all those intervening
conipri.se the internodal joints. Tho nodal joints of the Inadunata and
Camerata, and also of many of the later and recent Crinoids. were intro-
duced directly beneath the basals and infrabasals respectively, so that the
uppermost joint was always the j'oungest joint of the stem. But in the
young Comatula, in which the top joint sub.se(|uently develops into a centro-
dor.sal, in the recent Mesozoic Milkricriims, and probably in tho recent lihho-

THE CKIXOIDEA CAMERATA OF NORTH All ERICA.

crinm and Culamocn'iiiis, and in all Ichtliyocrinidae, so far as observed, the
new nodal joints were formed beneath the top joint, and the latter remained
permanently attached to the calyx. In Ajuocrinus, in which for .some dis-
tance the upper end of the stem is greatly inflated, and the proximal joints
extremely long, it is possible that the nodal joints were introduced below
the inllatod part, for there appear to be no innnature segments between the
upper joints.

The intcrnodal joints, as stated, are placed between the nodal ones ; and
the spaces whicii they occupy, and which continually increased in length and
widtli ill the growing Crinoid, are the internodes.

The i.icrease in the length of the internodes took place gradually in a
downward direction — as may be seen by comparing the stem of a 3'oung
specimen with that of an older one — and ixtri passu with the formation of
new joints just below the calyx. Hence in the upper part of the stem there
is a vaiiable number of premature internodes. Those nearest the calyx are
the siiortest, and consist of the smallest number of joints ; wiiile the inter-
nodes in tiie lower part of the stem all contain the same number of pieces,
and all joints have approximately the same proportions. The joints of the
upper part vary in the same internode from a growing leaflet, invisible in a
side view, to an almost fully developed joint ; and the upper internodes fre-
(juently consist of single pieces. But they are followed more or loss rapidlj'
by internodes of two, three, or as many more ossicles as it required to com-
plete the maximum number of the species, the younger joints being inserted
ne.xt to tile older ones, which are distinguished by their greater prominence.
In the upper part of the stem, the joints of subsequent growth are readily
recognized, in some •-pecies more .so than in others ; I^ut toward the terminal
end, where all ossicles attain almost nn equal size, it is often diflJicult. The
stem matured from tlie root up, and remained at the upper end permanently
in a state of immaturity.

The maximum number of internodal joints varies con.siderably among
the species. There may be only one or two to the internode throughout
the stem, or many more. The largest number observed in Paleozoic Cri-
noids is about fourteen ; but among recent Pentacrinida) as many as forty-
flve have been counted, and as many as seventy in Mesozoic species.

The internodes of some species begin at quite a distance from the cal^-x,
while others have no internodal joints at all. The former is manifestly the
case in certain genera of the Ichthyocrinidaj, in which the upper part of the

MORPIIOLOGICAL TART.

stem is enlarged somewhat as in Ajn'ocrmis, except that the joints of the en-
hirged part in tlie lehthyocrinidac are very short, and increase but very
shghtly in length downward. These plates, which have no internodals inter-
posed, extend to the full length of the inflated part, and their number varies
in different species from about twenty to fifty, but is constant, or nearly so,
in the same species. They are followed distally by a large prominent
joint, from which the internodes begin. The latter are formed in the usual
way, larger and smaller joints following each other at interv.als, and the
nodal joints are rather prominent.

The stem of a Platjcrinus has generally no internodes, and all young joints
were introduced next to the basals. The joints are elliptic, and the apposed
faces of the joints throughout this genus are provided with articular ridges,
which follow their long diameters. A similar structure occurs in the recent
Rhizocrimis and Balhi/ci-iims, and both of them are apparently destitute of
internodals. The Silurian Mursvpiocrimts, however, with a circular stem,
which is otherwise most closely allied to Plati/crimis, always has well defined
internodes ; and this forms perhaps the best distinction between the two
genera.

The absence of internodals is not confined to specimens with elliptic
stems, or to those with articular ridges. They are wanting also in Mespi-
locrimis with a round stem, and in which the joints rapidly attain a length of
from three to four times their diameter (Plate II., Fig. 3). In Ehodocrinus
there is, so far as observed, but a single ossicle to each internode, and
througliout the stem a larger plate alternates with a smaller one.

In a few Palreozoic Crinoids, the whole stem is divided longitudinally, its
joints being either quinque- or tri-partite. The former is the case in Ohio-
cn'nits, Edenocrimis, Barifcrbms, Ammalocrimis, and probably others ; while a
tri-partite st-^m has been observed only in Ilctcroerimis. The stem segments
alternate with the proximal plates of the calyx ; i. c, they are interradial
in dicyclic, and radial in monocylic Crinoids.

Most Crinoids are provided with cirri, which are given off from the nodal
joints at intervals, cither throughout the whole length of the stem, or only at
its distal end. The former is more generally the case among the later Cri-
noids, while in the majority of Palajozoio forms the cirri are restricted to the
lower part. In Neocrinoids they are more regidarly distributed, and occur
in whorls ; in Palneocrinoids they are generally arranged singly, and at irregu-
lar intervals. The Pentacrinida3 have five cirri to each nodal joint, which

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

are invariably radial in position ; or tliree cirri from one node, and two
from the adjoining ones, so arranged that the cirri of two joints corre-
spond in position to the five of the one joint. The size of the cirri varies
among species, some being ninch stouter than others and also longer ; but as
a rule, they increase somewhat in length downward, and taper to the end.
They move rapidly, according to A. Agassiz,* quicker than the arms, and are
used " as hooks to catch hold of neighboring objects, and on account of their
sharp extremities are well adapted to retain their hold."

The functions of the cirri in Palaeozoic Crinoids were probably more
limited than in recent ones, for in most of them any rapid movement
would be incompatible with the structure. This is especially the case
with those of the Camerata, and it may be a question whether these
appendnges should not receive a different appellation.

The cirri of the Camerata, except perhaps those of certain species of
Dichocrimis, are mere branches of the stem, and were obviously capable of
very little motion. They occur only in the lower part of the stem, and in
many cases were probably restricted to the root. They rest within sockets,
formed at the sides of the stem by a truncation or excavation of one or more
stem joints. In riali/crimis, in which we have observed the complete stem
more frequently than in any other genus, they generally occupy from one-
fourth to one-third of its length, and, being given off invariably from the
longer diameter of the stem, they follow its twist. In some of the species,
each successive joint is cirrus-bearing, either at both sides of the stem or one
side alternately. In others, the cirri are given off at irregular intervals, and
vary considerably in length and width. Throughout this genus they are at-
tached to one stem-joint only, which, when the base of the cirrus is larger
than the usual length of the joint, is lengthened on that side to accommo-
date it. The radicular cirri are larger than the others, and are generally
provided with numerous small branchlets. The distal end of the stem also
terminates in a sharp point.

In stems with internodal joints, the cirri do not rest alone against the
nodals, but the adjoining internodals share in the formation of the cirrus
sockets. In some species the sockets involve only the adjacent joint above
and below ; in others, two or three of them ; but the cirrus canal invariably
communicates with the axial canal of the stem through the nodal joint. The

• Ijptter No. 3, on the Dredging Operations of the U. 8. Coast Survey steamer Blake, from December,
1878, to March 10, 1879. Bull. Mus. Comp. Zool, Vol. V., p. 296.

[

^.w .«-•-»«• •

MORPHOLOGICAL I'ART.

cirri, although they may be arranged singly at wide intervals, are located
radially in dicyclic Crinoids, and interradially in monocyclic ones. This is
readily perceived on pentangular stems, in which the cirri rest within the
retreating angles of the joints, so as to alternate with the salient angles, and
hence are in lino with the salient angles of the axial canal.

Tlie length of the cirri among Camerate Crinoids was very variable, and
they were in some species quite formidable. Wo have in oar collection a
fragment from the lower part of the stem, apparently of Batocriiius graiulis
(Plate I., Fig. 2), measuring 11 cm. in length, and tapering from a diameter
of 10 mm. at one end to 7 mm. at the other. It gives off numerous cirri, of
which those of the thicker or upper end are but little thinner than those of
the lower. Three of the lower cirri are preserved to a length of 10, 15J,and
15 cm. respectively, and may have been much longer, as they taper but
little, still having at their ends a thickness of 2i to 3 mm. Five other cirri
are broken at a length of from 11 to 37 mm., and eight consist of only two
to five joints ; while the sockets of three others are empty. The sockets are
deeply excavated, and extend to nine joints, the surface being radiated. The
distal faces of the joints are slightly concave, the proximal joints shorter than
the distal, and the central perforation is round and of moderate size. Two
of the cirri in this specimen have a remarkable cyst of 14 to 18 mm. in
length by 9 mm. greatest width, one forming the distal end of the longest
cirrus, the other commencing about 8 mm. from the stem. The two thickest
joints in the inflated part of the one are nearly 4 mm. long, while the length
of the joints above and below the inflation does not exceed \\ mm. Similar
cysts are frequently found along the stem, but have not before been ob-
served to occur on the cirri. They resemble the Myzostoma cysts, which
occur along the arms of recent Comatulae, and like them were evidently
caused by parasites.

Ill another stem fragment from the Upper Ilelderberg of Louisville, Ky.,
every joint is cirrus-bearing, and most of them have five large cirri — some
four or three — which almost touch those above and below. The cirri are
preserved to a length of 35 to 40 ram., and were probably much longer
(Plate I., Fig. 3).

The cirri of the ActinocrinidoB generally extend to one third the height of
the stem. They vary greatly in size, and are arranged at rather wide inter-
vals. The same structure probably prevailed in the IchthyocrinidaB, at least
in Onychocrinus and Taxocriims ; while in the Calyptocrinida3 cirri occur only

THE CKINOIDEA CAMERATA OF NORTH A5IER1C.V.

at the distal enJ, where they form a large root with hundreds of small, very
delicate branchlets.

In Dtchocrinus the distribution and length of the cirri are extremely vari-
able. In some specii-'s they only occur at the lower part of the stem, where
they are short and arranged far apart. In others they continue up to near
the caly.x, and are quite long. The former is the case in D. inornatus, in
which they are singly arranged, and rather slender. In D. pamiliis and
D. iMimlus, however, they follow the whole length of the stem, and are
arranged in sets of two or more, Avhich are so long that the tips of the upper
ones reach up to the arms. But the most remarkable cirri occur in the
Carboniferous Ccaiip/ocriims mijcloductylus (Plate LXXV. Figs. 1 and 2) and
C. citrij'er (Plate LXXVI. Figs. 13 a, b, c), in which they begin at a short
distance from the calyx. The stem, as usually found in these species, is
coiled around the crown; the joints are circular at the top, but gradually
become crescent-shaped, the concave side of the crescent directed to the
inner side of the coil, and both its horns giving off extremely long cirri from
alternate sides. Very similar cirri occur in the Fistulate genus Ilequ'tocnnus,
from the Silurian of Europe.

Gli/ptocriiiiis apparently had no cirri at all, not even at the distal end,
and the stem was probably attached like that of the Comatula3 in their
larval state by means of a dorso-central, i. e., the enlarged terminal plate.
RhoJucnnus nanus and li. Kirbi/i have a few scattered cirri at the lower end,
singly arranged.

The cirri of the Inadunata, so far as observed, are not only more slender,
but were apparently more flexible than those of the Camerata, and they
pass up more frequently to the top of the stem. The latter is often the case
among the Poteriocrinidac, especially in SeupMocnmis and Graphwcrinus, in
which the nodal joints have variously from one to five rather delicate cirri.
That these appendages were highly flexible is shown by the fact that they
bend in all directions, — some being straight, others curling, some directed
upward, others downward, — a feature very different from that shown in the
Platycrinidas, Actinocrinidae, and Brtocrinidoe.

Bckmnoo'imis Jlorifcr has very long and slender interradially disposed
cirri, which extend to the full length of the stem. It has three or four from
each nodal joint, the upper ones directed upwards, and extending to half the
height of the arms. B. tifpus, on the contrary, has no cirri to a length of
13^ cm., and the stem is circular instead of stellate.

''f^

pnw

MORPHOLOGICAL TART,

In the Cyathocrinidoo the structure at the lower part of the stem is only
known in Jiaiycrimis. In Ci/ulhocrinus we have exatuined the stem to a
length of 10 cm., and in Pumocrimis to about 18 cm., without finding' any
traces of lateral cirri. Neither have these been observed, so far as we know,
among the Anomalocrinidaa or Hybocrinidiu ; but in JIumocrinus scopurlm
they occur at the lower half of the stem.

The stem of Duri/crimis is quinque-partite, and enlarges gradually to the
root, where its diameter in extreme cases reaches from 30 to 40 mm. The
root consists of five main rami, which branch into smaller ones, so located
that the longitudinal sutures of the stem bisect the rootlets, and the large
central canal, which is sharply pentangular in the stem, becomes elliptic or
linear within the branches ; the latter is also the case in Ancijrocriniis, of
which we shall speak presently.

The axial canal is central, and extends to the full length of the stem,
giving ofi' branches to the cirri. The main canal is circular, angular, or pen-
talobate ; that of the branches sometimes elliptic, the long diameter vertical.
If pentangular, the angles are directed radially in dicyclic Crinoids, and
interradially in monocyclic, thus alternating with the projecting angles of
the stem joints. To this rule, however, there are two exceptions, and, so far
as we know, only two. In Pcntacrimts, and the monocyclic Gli/ptocrbim Forn-
shelli S. A. Miller, the axial canal has the same orientation as the outer angles
of the stem. This is very remarkable, and we shall consider it further in
discussing the basals and infrabasals. The canal in some species is quite
minute, in others very wide ; while in still others the central canal is sur-
rounded by three, four, or five peripheral canals, as in the case of Cuprcsso-
criiiiis, in which pentamerous symmetry in the stem is the exception.

In recent Crinoids the innermost part of the central canal is the internal
vascular axis, and consists of five peripheral vessels arranged around a cen-
tral one. The former are downward extensions from the chambers of the
quinquelocular organ at the base of the calyx, which are connected with the
axial vessel of the chambered organ. Whether such vessels also existed
in the stem of Palaaozoic Crinoids, of course cannot be ascertained from
the fossil ; but that a quinquelocular organ, with upward extensions to
the arms, was present in some of them, is indicated by the structure of
Eupachifcrinus, Catilloerinns, and Agasskocrinm, where the inner floor of the
basals and radials is apparently perforated. Carpenter * thinks it probable

• Journal of Anatomy and Physiology, Vol. XIL, p. 44.

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

^;!

that tlic peripheral canals of Ciijircssocrintis, which consist variously of three,
four, or live separate passages, correspond to the peripheral vessels of Pmla-
criinis, Jk/iisocriiius, and other recent Crinoids. He directed attention to the
fact that there is among different individuals of the same species considerable
variation in the if<olation of these vessels. In some species, in which the
canals appear to be continuous, there is but one large tri- or tetra-partite
perforation at the base of the calyx and throughout the stem, which he
thinks enclosed the four, five, or six separate vessels of other specimens.
This may be so, although we cannot quite understand how the three or four
peripheral canals, where they exist, can be extensions of a quinquelocular
organ.

Tlie variation in the size of the axial canal among Palncozoic Crinoids is
most remarkable. In Plalycrinus the canal is sometimes no larger than the
point of a needle ; while in Barycrinus, Cvfalocniius, Eitallocriiius, Alegistocrimis,
Pmcc/iocriiiKs, etc., it is often from one half to even three fourtlis the width
of the joints, and is either round or pentangular. In some of them the walls
within appear as if built np of thin lamina) with spaces between, sometimes
pectinated and variously sculptured, producing a great multiplication of
exposed surfaces. In Bari/crinus, with a quinque-partite stem, and a sharply
stellate canal, of which the projecting angles are directed radially toward
the suture lines, the trigonal inward extensions of the canal are pierced
by one or more rather large pores, which pass through the body of the
plates, so as to enter the outer faces of the stem, as shown on Plate I.
Figs. G and 8 a, h. Five other series of pores follow the longitudinal suture
lines, and these also communicate with the central canal.

In the CrotalocrinidoB and Periechocrinites, in which the central cavity is
proportionally still larger than in Biiri/cniius, the inner structure appears to
liave been less complex ; but its extreme size in both groups, compared witli
that of other Crinoids, and especially with recent ones, seems to imply that it
was not a mere axial canal, but performed additional functions.

We have in our collection the root of a large Bai'^cnmis (Plate I.
Fig. 7), which must have been attached to a smooth, solid substance, for
the lower surface of the root is perfectly flat. In this root only two of the
five primary branches were developed, and these are but partly preserved,
but enough is seen to show that they had been placed on a level with the
truncated lower face of the main trunk. The development of the other
three cirri seems to have been checked by contact with the bottom, but their

'^ —mi

'v>«K,v.sSiarw«K ig w r- *

JIORPIIOLOGICAL PART.

outlines arc faintly indicated along tlio edges of tlie specimen. Tlie middle
part of the truncated lower face is perfectly flat, and there are no traces
sliown of an axial canal. But in an outward direction we find grouped
around a closed centre numerous small canals comiecting with the interior.
These canals form upon the surface well defined ramifying grooves, which
pass out to the periphery, and seem to communicate with the surrounding
water. In another detached root, likewise with a flat bottom, tiio rami-
fications at the distal end were not exposed in tiic specimen, but wore
opened out by grinding. The specimen has two root trunks of eqiiiil size,
which are united at the bottom by an irregularly formed limestone deposit,
and around the projecting truncated lower end there are a numljer of
small openings, which connect with the canals from the two rootlets.
Whether the cirri of all Palncozoic Crinoids open out at their ends, will
perhaps never bo satisfactorily ascertained. may state, however, that

the finest hair-like branches which have come under our observation are
perforated at their extremities.

When in the Revision we directed attention to the variations in the size
and complexity of the axial canal (Part I., p. 15), we suggested that the
column was probably in .some cases, and perhaps in all Pala;ozoic Crinoids,
subservient to respiration. To this Dr. P. H. Carpenter* replied that he did
not think it unlikely that the pores near the ba,se of the column may have
served to admit water into the stem, and thence into the ca>lom ; but he
doubted if the canals opened at the ends of the rootlets, concealed as
they were below the surface of the ooze, as the water introduced to the
stem by those passages could not have been very useful for respiratory
purposes. Neumayrf regarded the stem of the Crinoids a greatly modi-
fied organ, whose original form could only be explained by the structure of
certain Cy.^tids ; and ho thought it was primitively, as it is in tint group,
a sac-like extension of the calyx, and was plated in a similar manner. In
corroboration of liis views, he alludes to our observation that in Crinoids
with pentangular stems the faces and angles of the stem occupy a definite
position to the proximal ring of the plates in the calyx.

Similar views were expressed by A. Agassiz. t He says : " Tiad the pen-
tagonal stems hold a definite relation to the calyx has been clearly shown

• Quart. Joum. of Gcol. Soc, 18S0, pp. 555-557.

t Stiimme ilci Thicrniclics, p. 430.

X Calamocriuus : Mem. Mus. Comp. Zool., Vol. XVII., p. 63.

THE CKINOIDEA CAMEKATA OF NOUTII AMERICA.

by Wachsmuth and Springer, anil goes far to prove that the stem must
originally have had a liir more intimate connection with the calyx than its
representatives of to-day have ; and the fact that in a number ol" Palujoioic
Criiioids the axial canal is very wide, compared with that of recent t3poH,
seems to indicate an additional function t'» that pf the axial canal, which, as
Noumayr suggests, we cannot explain fr^m recent representatives."

The apposed faces of the stem joints, with a lew exceptions, are marked
by a series of more or less well defined angular ridges and alternating fur-
rows, which radiate from the opening of the central canal toward the dorsal
margin of the joints, but occasionally are restricted to their marginal por-
tions. The principal ridges alternate with smaller ones, which do not extend
as far inward as the others, and all ridges of one joint meet corresponding
furrows of the apposed joint, which gives to the suture its serrated outline.
The faces of the joints are Hat, or slightly curved, the nodal ones having
sometimes a slight crest around the canal, which fits into a corresponding
depression of the apposed internodal. Tins indicates that the motion of the
stem was quite limited, and, as Carpenter remarks, "only of a passive char-
acter, due to the current of the water, etc., and independent of the will of
the animal." On coming in contact with other animals it was capable of
bending sideways, and of returning to its natural position when the obstruc-
tion was removed.

In Platycfinus and Bourgucticrinus, in which the faces of the stem joints
are elliptic, their surfaces are provided with a well defined transverse ridge
following the long diameter of the joints, with fossae at both sides, and
surrounded by a marginal reticulation. The ridges follow the twist of the
stem downward, admitting motion in all directions. In these families there
seems to have been a sort of rudimentary articulation between the suc-
cessive joints, while in the other families there was only a loose sutural
union.

As to the habits of Crinoids, very little is yet known, even of the recent
ones. We know that in their pedunculate state the Comatuloo were fixed
by means of a large plate, the so-called dorso-central ; and this led to the
belief that all Stalked Crinoids were permanently attached in a somewhat
amilar manner. But this has never been satisfactorily proved, and, as we
know now, is not always the case with the recent Pentacrinidac. The distal
end in most PaloDocrinoidea tapers rapidly and uniformly to a point, and the
terminal branches are given off from several joints, and not from a single

MOKrHOLO(JICAL TAUT.

one, except in a very few cases. In the Hudson River group of Cincin-
nati we occiwioniiUy liiid crinoiiliil disltH, attaclied to pieces of coral, which
closely resemble the dorso-ceiitral of Antcdun. These disks have a pit or
depression at the middle of the upper face, sometimes enclosing a small
stem joint. They are irregularly round, and some of them have small pro-
cesses passing outward from the sides, which seem to represent primitive
cirri (I'late 1. Figs. 9, 10), It is now worthy of note, that we find in
the same bods somr remarkable crinoidal stems, with their lower ends wound
around some stem fragment or other object, almost as neatly as thread
upon a spool, the column gradually tapering ns it coils, and becoming very
small at the end.* It has always seemed to ns that these stems and the
terminal plates belonged togt-ther, and were separated during the life of the
Crinoid. Detached roots are found in considerable numbers at Burlington
and Waldron, and in almost ever^ case the root parted from the stem a little
ab'^ve the radicular cirri; but it it: curious that hardly ever are parts of
the crown found associated with them. From these facts we may infer that
the stem, at least in some cases, became iletached from the root, so that the
Crinoid could change its place of attachmont. A detachment of this kind
actually took place in a large number, if not in all, recent PentacrinidoB, as
.shown by Sir Wyville Thomson,t P. 11. Carpcntf, and others. The former
describes this structure in Piulaenmis W//riUc-Thniiiy>iii as follows : " All the
stems of mature examides of this species end inferiorly in a nodal jo' it
surrounded by its whorls of cirri, which ciu've downwards into a kin', of
grappling root. The lower surface of the terminal joint is in all .smoothed
and rounded, evidently by aI)sorption, showing that the animal had for long
been free. I have no doubt whatever that this character is constant in the
present species, and tha< the animal lives loosely rooted m the soft mud,
and can change its place at pleasure by swimming with its pinnated arms;
that it is, in fact, intermediate in this respect between the free genus
Antcihn and the permanently fixed Crinoids." Carpenter found a number
of other species o^ Poidtcrinii-", and some of Melacrimis, in the same condition.
Roots apparently of Pcn/acrinm, and belonging to mature or almost mature
specimens, are occasionally found on telegraph cables, but so far as we know,
minus the crown and main part of the stem ; and it is qnite probable that
all PentacrinidoB were able to detach themselves and float about.

• S. A. Miller : Joiirii. Cindn. Snc. Nat. Hist., Vol III. Plate 7, Fig. 34.
t The Depths of the Sea, pp. 442-4 14.

TIIK CmXOIDKA CAMKUATA OF NOKTII A.MKHKA.

Ciii'pcnter * further Htiitcs that in Piiittwriiiiis Wi/vllU-lhoiiiHon! iha x\oih\\
juint Iruiii wliieh thu Hcpiinition takes place " MOiiietiiiies Iosen its ordinary
chiiructcrs altogether, becoming nuicli enlarged and rounded below ho an to be
almost heniisplierical in appearance." And in a t'ool-noto lie miys : " The un-
usual enlargement of the nodal joint sug'jestH the idea that tlie structures
which have been descrilted by Hall under the name Aiic'/rocniniK i may be the
detached stems of a I'ahuocrinoid in the semi-free condition," — in which we
fully agree with him. Aiici/rncilni.i has the form of an anchor, with four lidok-
like processes aroimd n central ascending stem, which nt its distal end is
provided with a small, rounded tubercle, closing the opening of the central
canal exactly as in some cases of Piv/iimnnn. That this stem is morphologi-
cally in the same condition as that of Pnilucriinn*, nobody will deny nfler
examining the specimens. The four lateral extensions were doulitless radi-
cular cirri, whose joints were obliterated by calcareous overgrowth, as in the
lower part of its tetramerous stem.

Something similar to this may have taken place in other Palicozoic Cri-
noids; and it is (|uite pr()I)al)le that the terminal end, as it appears in the
specimens, is in many cases not homologous with the part by which the
young Crinoid had been formerly attached, but is a product of later growth.
We suspect this to be the case in the Actinocrinidio. Platycrinidtu, and other
forms in which the terminal part tapers rapidly to a point, and cirri are
given off from the sides. It would not I;e a great departure from the
structure of the Comatuhv, if we bear in mind that their centrodorsal is
a modified stem joint, bearing cirri upon its outer surface. The only
essential difference would be that in the Pala^ocrinoid the stem separated
at its Imnr end, anil in the Comatulao at the tipper.

That the young PaUvocrinoid in its early life was attached by a dor.so-
central, we may fairly infer from what we know of the dcveloinnent of the
Comatuhe, ami from pala?ontological evidence. The indications, however,
leave it somewhat douI)tful if the fi.xation was permanent. We believe that
in the majority of cases among the older Crinoids the stem was afterwards
separated from the root, and that the animal subseiiuently led n free
lift. In only two instances do we know that Paheo/oic Crinoids were
attached by what appears to have been originally a dorso-central plate : in

• riinllciipor Rep. on \]\c Stalked Crinoids, p. 19, nnd fnot-nntc.

t Fil'lecnth Ann. llcj)., X. Y. Si'ilc Cab. Niit. Hist., 1802, pp. 89, 90.

MOia'HoLOGK'AL I'AIIT.

" Chii'forriiiii.s " (litni.i* nml in h'/ini/iz/i/nrnnitu minxiix.j Ixitli (k'scril)iMl liy
II;ill. Ill tliu roniicr till- pIiUo jm lixod to a .Mtem riiigmeiit, and clo^t'ly
n'noiiil)lt-'!< till) i»liile lijfiiiL'd \)\ nn on I'liitu I. Fi^s. [), 10, liiiviiijr likt- tliiit
Hiiiall l)inl(liiig cirri. Tiie /■JifcK////i/uriiiiii'< \n a young Hpociiiicn, wliich niiiy
liave iKM'isliL'd ijul'oie leaciiing the fioi' stiigo, Dclaelifd roots of this ><iiccic'H
have Im'cii luiiiiil in hirgo mniiljers, even hir^aT onus tliaii tliat rij,nirt'd liy
Hail. Ill some localities they are .so aliiiiidant that they lie in coiitaet in the
roek ; but tliey nro very rarely associated with i)iece.s of the stem proper, or
with [larls oC the crown. These roots .seem to have liei-ii ilerived Croiii a
central disk (dorso-centrul), iVoiii which tlie niiineroiis hranehes were given
olT in a similar manner as the immntiire cirri IVom the terminal plate of
'' Cliilnirn'iiitx " vidnis.

Among recent (.'rinoids, siicli terminal ])lutes have been found in ronnec-
tion with fragmentary stems in V<il<iiii'iriliiiis Dimiivi/cH Agassiz.t and in J'cii/n-
triiina unrcsliiinis Carpenter,^ in which the stein increases in width downward ;
but it is uncertain in lioth cases whether the stem is fractured or hail been
cast olT by the animal. DilVeieiit is the striictuio in a specimen of IUiImi.
cnniis ^{iwsiiiii, ligured by Car[)eiiter. || in which it seems as if the dorso-central
is unrepresented. There arc given oil' Irom (he sides of the last stem joint a
few irregular cirri, directed downward, and tbe distal end of the joint is
closed, as in the case of semi-free Pentiicrinoids. The last joint dilTers in no
other way from tbe joints above, and has the same form and length as the
preceding one.

Among Palivo/oic Crinoids wc have seen tbe complete stern in upwards
of thirty specimens of various genera, but none of them bad a dorso-contral.
or a surface for attnehment ; the steins invarialdy terminate in a point. The
terminal portion, however, forms no part of the primitive stem, but is of
later growth, and probably served the same purpose as tbe lateral cirri.

Now if it is true that the young Crinoid was attached b^' a dorso-central.
as we may suggest from the ontogeny and pliylogeny of the group, then all
these specimens are morphologically in alioiit the .«amo condition as the semi-
free Pentacrinidie, and not essentially different from that of the free floating
ComatuliV. This interpretation seems far more reasonable than the sup-
position that these Crinoids were permanently attached.

• New York Sintp Cal). Niit. IlisI ; FilVonlli Rep., Pliitp I. FIrs. 17 nnd 18.
t New York Stale Miisnim N»t. llisl.; Twi-nly-ciglith Hop., I'liito V, Fi?. .'>.
i Oil Ciilainoct'ims; M,m. Jliis. Coinp. 7,o<il., Vol. XVII. I'lato 28, Figs, i, .i, 4.
§ riiall. Uc|.. oil Sialk. Ciiii. ! I'lale XXX. ii, Fig. I.
II Ibid. I'laleLlII. Fig. 7.

!,'

THE CKINOIDEA CAMKltATA OV NoKTIl AMKIUCA.

A ponimiieiit iixiitiuii uf tlio C'liiiuids would i>urlmim luHtrict thu geo-
gi'iipliifiil niiigo of tho 8j)ucii'.x, wIiciviih \vu know that woiiiu of them hiivo
a very wide range. A niiijority of tho 8pi'«'io."* from the Lower Rurlington
group lit Hnrlington are I'oimd iihnost muiltered in tlie Honthwi'sterii part of
New Mexico, and somo in Arizona, and nniny Hpeeien of tiie KeoUiik group
have been traced from southern Iowa um far down an Ahibama. An(] we find
in Scotland and eastern RuHsia, with but flight modification^, tlic same form.<*
wiiicii fiourinhcd in tiie MinHis-ipiii Valley during the epoch of the Kaskaxkia
gro\ip,

B. Bdsak anil Iiifrahttsals.

Tho bnso of a Crinoid consists cither of one or two rings of plates, to
which the terms •'basals" and " infrabasuls" arc applied. In dicyclic forms,
the infrabasals constitute the proxinial ring of the calyx ; the basals the next
circlet above. The former are radially disposed, tho latter interradially.
The plates of either ring are in contact laterally, except tho basals in a few
species of Zi vcriiws and Culpiommis, whore tho truncated lower angles of tho
radials, and occasionally tho radianal, reach down to the infraljasals. The
basals are followed directly by tho radials, except in the Acrocrinida>, in
which they are separated from tho latter by a belt of auxiliary pieces, wljich
occupy a large part of tho dorsal cup.

Tho term " basals " was applied by the earlier writers invariably to the
proximal ring of tho calyx, and when there were two rings, the plates of the
jippcr one were called "subradials" by somo authors, while others called them
" paniba.salia." To Dr. P. II. Carpenter* belongs the credit of having been
the first to point out that in dic^-clic Crinoids tho so-called "subradials" —
and not the proximal ring — are the homolognes of the basals in the mono-
cyclic base, and that the lower ring in tho dicyclic forms is an additional
element in tho calyx. He demonstrated that from n niorplmlogicnl point of
view the same set of plates cannot be interradial in one genus, and radial in
another, and he considered the basals, which alternate with the radials, to be
the representatives of the genitals in the Urchins. The force of his argu-
ment has been generally ocknowlodged, and the American authors writing
since 187fl have adopted Carpenter's method, with the exception of S. A.
Miller, who still clings tenaciously to the old terms. Carpenter called tho
plates of the proximal ring " under-basals," for which the term " infrabasals"

* " Ornl and Apical Systems of Echiuoderma." Quarterly Journ. of Microscop. Sci., Vol. VTII.,
pp. 351-383.

MOItnioUKilCAI, I'AIIT.

ImH boon HiibHti tilted, at the Hiigj^t-Mtion of I'lDr Zittul. But Zittel,* nnd i\u>
Ocriiiiiii I'lilu'oiitoIogiHtM giMicnilly, wliilo admittiiijj! tlic 'lomology, mid ilic
tiiiinu " iiit'iiilmsiiliii," iidoptoil tlio ti'tiii " |iiii'iibiiNaliii " fur llii> upper ring of
pliitL'M ill lliu diryclic base, cluiniing tliiit tho word " biiwalH," if iipplivd to
the dicydic liane hk wtdl, inigiit kad to coiiriisioii.

Tbo practice of giving ditVorciit natiicH to m'Im of plates wbich arc nd-
niittoil to bo boiiiologoiis was jiisfly criticisi'd by Carpi-iitor.t and nerioiis
didiciiltius arise as to wiiicb term should be applied in certain groups, where
infralmsais exitit in some species and are wanting in others. Such a case is
presented by tho Apiocriiiidie, among which de lioriol discovered niilimeii-
tJiry infrabawils in two Hpccics of MiKerkniiiin. t This family was previously
supposed to bo monocyclic, and tbo base is described by Zittel as consisting
of live buxiilit, whereas in the two species above mentioned, the live corre-
sponding plates would be imrahasulx. There is a similar case among the I'eiita-
crinidiu, in which infrabasals are represented in one genus, — Krlnivrhtvi'.
Ill the Comatulic, in which, according to Burj,§ small infrabasals occur in
the ciliated larva, but disappear in the Peiitnf rinoid Htages, the very same
plates would bo " parabasa'.-i " in 'be ear'ier stage, and basals in the later.
Carpenter is clearly right when I" says ihat this terminology, instead of
making it easier to students, as claimed by tho Gerir.nii Pala'ontologists,
would bo the source of endless confiL-ion.

A different interpretation of the basal plr^*! ..as given by Dr. J. Wnl-
ther.ll lie accepts Zittel's terms for de.scripi.vo pnrpose«, hut homologi/cs
tho infraba.sals with the ba.sals of tb' i's nocyclica, tho >/arabasalia " with
the monocyclic radials ; and ho tak s tin radials of the Dicyclica to repre-
sent an entirely new element in crinoid morphology. This recall Om idea
of Lyon,** who took the basals of the Blastoids for '• primary radials," and
tho forked plates for " secondary radials." As Walther's views are alto-
getbor out of keeping with the facts of Palaeontology, and also, as we now
know, with those of tho enibrjology ol recent Crinoids, any further discu.s-
sion of the subject is unnecessary.

The Comatulao have basals only in their earlier stages ; during the later

• Ilandbuch d. Pnlneoiitologip, Vol. I., p. 327.

t Aim. mid Mng, of Nat. Hist., Julv ISUO, pp. 5-11

I I'lvleontuldRic rrm.faio^ T >nip XI., I'art I., pp. ,').">3, Bfi6.

5 "The Early Stages in ''■ />r-, iopiiioiit of Aiilcdoii rosacea." Report of the Fifty-seventh Meeting of
the liiitish Association at Mancni>.<r, 1887, p. 73.5.

II Unlcrsnchnnjjen iihcr den Ban dir Ciinoidccn, Fnlaeontograpliica, ISSfi, Bd XXXII., p 189.
•• Geol. Rep. Kentucky, Vol. III. p. 469.

I'.

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

period of Pentucrinoid life they are transformed into tlie " rosette," wliicli
closes the upper opening of the centro-dorsal cavity lodging the cliandjcred
organ. The Engeniaerinida) have no hasals in the adult, and Carpenter sup-
posed that they were anchylosed with the radials, while Zittel and Jaekel
think they were enveloped by exuberant growth of the radials.

In all dicyclic Crinoids tiie basals, without exception, consist of five
plates, and the infrabasals either of five, three, or a single piece. The basals
of monocyclic Crinoids vary in number from one plate to five.

The proximal ring, whether con.sisting of one, two, three, or four pieces,
whether ba.sal or infraba.sal, is divisible into five elementary plates ; and the
smaller number, where it exists, is produced, as we shall presently show, by
anchylosis of two or more of the primary segments, accompanied hy a more
or less complete obliteration of the suture lines.

The earliest dicyclic Crinoids had five i:ifrabasals, and the first mono-
cyclic ones ii\Q basals. Before the close of the Ijower Silurian, there ap-
peared two monocyclic genera with four basals, both having a special anal
plate interposed between the radials. The quadripartite ba.se reached its
culmination in the Upper Silurian, and disappeared before the clo.se of the
Devonian.

Tlie earliest genera with a tripartite ba.se occur in the Upper Silurian ;
some of them have an anal plate, and others not. When that plate is
represented, tiie basals are of ecjual size; when ab.sent, two of the basals
arc c<(ua]. and the third about half smaller. The two forms continued to
exist side I)y side tc the end of the St. Louis group of the Carboniferous,
when both became extinct.

The bipartite base is restricted to the Carboniferous. It occurs from the
Kinderhook group up to the Coal Measures, but is found only among genera
with a large anal plate.

It is evident from the.'io observations that the number of ba.sals was grad-
ually reduced in Paheozoic times, and that in ihc Camerata the anal phite
was introduced after the quadripartite base had made its appearance. It will
now be .shown that this diminution of number was the result of fusion of two
or more of the five orijrinal plate.s, and that by the introduction of the anal
plate tiie I)ase underwent further modifications. The manner in which the
modifications in the number of ba.'^als and infrabasals wore efl'ected. may be
best understood by reference to the diagrams on Table A.

Looking at these diagrams, the transmutation in the Camerata from five

MOKPUOLOGICAL I'AUT.

TABLE A.

IchthyotTinidsB.

lehthyfMTinidie.
18

Rhodocrinidie. Thyaiinocriniilie. Apiocrinidas (young). Apiocrinidre (adult).

DI.VOnAJrS ILLUSTHATINO THE EVOLUTION OF THE BASALS AND INFRABASALS.

All fisnros rrprcsciit the anal side at the top; « = posterior basal j d and « = postcro-lateral basals; c and </= anterior
basiils ; /, g, h, /', /• = infrabasals.

THE CUINOIDEA CAMERATA OF NORTH AMERICA.

baanls to a less miiiiber, is readily iindeislood among genera in whiili the
anal plate is wanting. Wlien the ba.se is (inaihipaitite, it is invariably the
two anterior plates of the elementary live which are consolidated (I'ig. 2).
In the tripartite base tiiero is a 1'ii.sion of the posterior with the left postero-
lateral i)asal, and another between the right posterior and adjoining antero-
lateral-plate (Fig. 3). The figure shows that a bisection of the two larger
plates will reproduce the original live pieces, interradially dis]H).sed.

The case is nut .so simple in genera with an anal plate, where the form
of the basal di.sk is changed from pentagonal to hexagonal (Fig. 4). ns a
bisection of the larger plates woidd produce six plates instead of five. This
dilliculty, however, is overcome if we consider that the introduction of the
anal plate into the ring of radials necessitated corresponding modifications
among the basals, as othersvi-e these plates wouM lo.se their interradial posi-
tion. It re([uired either the introduction of a basi-anal (date, or an increase
in the si/e of the original pieces. That the latter occurred among the Came-
rata is clearly shown by the diagrams, ami the evidence leaves no doubt at
what part of the base the extra width was in.serted.

Taking first the quadripartite base, and comparing Fig. 2 of the diagrams
with Fig. 8 — one pentangular and the other hcxangidar — we fmd that in
the latter the posterior basal has doul)led in size (Fig. 7). without materi-
ally changing the orientation of the plates, or disturbing their general
arrangement.

In tiie tripartite base the change was accomplished in a diflerent way.
Tiicre X is added to plate c (Figs. !) and 10), and the plates «// and c</ have
coalesced, and hold relatively the same position as in Fig. 3.

Tlie bipartite base is protiably derived irom the tripartite (Fig. 4), which
preceded it in time, and x, which in (he latter constituted a part of c, is
imited with cd, and ah with c (Figs. 11 and 12).

Now, taking up Fig. 7, and eliminating .r, .«o that the side of plate u rests
against the plate c, we obtain Fig. 2, and by a similar procedure we arc
enabled to transform Fig. 9 into Fig. ,{. The hexagonal base is thus re-
stored to its primitive pentagonal form without disturbing the orientation
of any plate, cninpDund or simple.

A most beautifid confirmation of these observations is furnished by an
abnormal specimen of Tcluocriitun umhrosu-i in our collection, in which the
regular anal plate is wiinting. TilrincriiiUK has normally throe equal basals,
but in this specimen the basal plaii to the left of the anterior ray is reduced

MORPHOLOGICAL TART.

to one half its normal hIzc, leaving tlie basal disk exactly like that of forms
whicli are normally without the anal plate.

It is very remarkable that while in all Crinoids with an unequally tri-
partite, monocyclic base, the smaller plate is located to the kfl of the anterior
radial, this plate in the base of the Bhistoids lies invariably to the rii/lil
(Fig. G).

Among monocyclic Tnadunata, in most of the genera, the changes among
the basals are not so readily traced as in the Camerata, owing to the asym-
metry of the radials, which more or less aifected the form of the basals.
Most of them have five basals, but there are some genera with three and
four. Anomalocriiiun, .so remarkable for its asymmetry, has five basals, but
there is frequently a small additional plate interpo.sed beneath the extremely
large left posterior radial. As this plate is only occasionally represented,
it i.s probably not of much morphological importance. S/orl/iiiiffocn'iiiis and
S>/i)iktlfiocn'ivi.s have three unequal basals, arranged like those of the Platy-
crinida). The Calceocrinidno have three or four basals of a decidedly irregu-
lar arrangement. Dchmiiocfinus- is the only known monocyclic genus with
five basals in which the regular anal plate is represented ; but the plate is
quite narrow, and affects but .slightly the symmetry of the plates of the
proximal ring. In the FTybocrinidir, a large radianal is interposed between
the radials, and the basals consist of five plates of a rather irregular form.

That the .smaller number of basals is a modification of the original five
plates, is indirectly shown by the fact that in many species o^ Plidi/cnims the
plates are so closely auchylosed that no vestige of suture lines can be seen.
In some of them the lines are marked by grooves, while in others oven the
sutures are plainly visible. The sutures arc always better defined in a
young specimen than in the adult, and in some species can be seen the out-
lines not only of three, but of five plates. It is further significant that in
all ritit;/criid of the Warsaw and St. Louis groups, the suture lines are ele-
vated, and transformed into ridges by excessive deposit of limestone matter.

The case of Pisocrinus is very interesting. The Silurian speeies plainly
show five basals, while those from the Devonian of the Eifel, which have
been referred by Schultze to IVificriiim, very often have but three. A care-
ful examination of a large number of Eifel specimens leaves not the least
doubt that in some of them there are still five plates, while in others of the
same species the number is reduced by anchylosis to three. Among recent
Crinoids also, Carpenter and others have noticed a fusion of the basals in

If,

THE CllINOIDEA CAMEHATA OF NORTH AMERICA.

Ilyocriima and Rhizucnniis, and it is possible that tiie former ims really but three
basals ; but in liluxocnnm the fusion was not complete, as Count Pourtales
proved by inserting a needle in the central canal, whereupon the base sepa-
rated into live pieces.*

Tiie foreyoing facts are of considerable importance as to classification.
For if the smaller number of plates is merely a modilicution of the originiil
five, the number of basals cannot be regarded as a good character for sepa-
rating tiie Crinoids into primary groups, as was practically done by Angolin,
and afterwards by S. A. Miller.

The basals of dicyelic Crinoids, as we have stated, invariably consist of
five pieces, but their form differs in different group.s. In the Rhodocrinidio
(Fig. 17) they are all heptagonal ; while in the Thysanocrinidte the posterior
one is heptagonal, and the four others hexagonal (Fig. IS) — the former
supporting a supplenientary plate at each intcrradin.s, the latter at the anal
side oidy. In the Fistulata, all five plates arc hexagonal when there is no
anal plate, as in the Encrinidtc ; but in the Cyathocrinidiv, whenever that
plate is represented, four of the basals are hexagonal, and the fifth hepta-
gonal, precisely as in the Thysanocrinidic. In the Poteriocrinidie. and all
other families in which in addition to the regular anal plate a radianal is
represented, oidy three of the basals are hexagonal, and the posterior and
right postero-lateral basals are heptagonal (Fig.s. 15 and 10).

The same variations occur among the basals of the IchthyocrInida\
Those of Ivhihi/iimiitis agr'o with the I>asals of the Encrinidiv ; those of
Mis^ii/iicriiins, TiiXdcriinifi, For/ic.yiorrniia, and Culjiiocriiius, with the i)lates of the
Cyathocrinidiu; while the basals of Lrriiiiiirriiiii><, 0' iioriiiincriiius i\m\ tS'iii/niomiiits
are in a similar condition to tho.se of the Poteriocrinida\

Tineo infraba.sils have been oljserved only among the Fistulata and
Articulata. They are represented sparingly among the former, but are the
rule among the Tilithyocrinida;, and are represented in the larva of the
Comatuhe. Wherever they occur, they consist of two large plates and a
smaller one, which are differently arringed in the various groups. In the
Fistulata, according to Bather, the positiim of the small plate is not constant;
we have always found it located anteriorly below the suture between the
two anterior basals, and the plates / and ff and / and /,- fused together
(Fig. 10). In the Iclithyocrinida', however, the small plate rests below the
siiture between the posterior and right postero-lateral ba.svl, and/ and y and

* Jli'iiioirs Mus. Coinp. Zool., Vol. IV., p. 29.

MORPHOLOGICAL PART.

// and /, respectively, are iinitetl (Fig 13). As tiiis Htrncture is apparently
constant in the latter group, we regard it as of some importance as regards
classification.

The introduction of the anal plate did not affect the Imsals of dicyclic
CrinoidiS in the same numner ns in the monocyclic. While in tlie latter,
when the plate is represented, the orientation of the basals is slightly dis-
turbed, in the dicyclic forms it remains unaltered. The anal plate of the
latter rests invariably upon the truncated upper face of the posterior basal
(see Figs. 11 to 18); while in monocyclic Crinoids it is supported by the
basals a and e (Figs. 10 and 12), or occasionally by a and .r (Fig. 8).

The infral)asals are completely anchylosed in the Cupressocrinidiv, fJas-
terocomidiie, and in S/riiiiiKiiovn'iiiis, where the}' form an undivided disk, which
Carpenter and others have regarded as representing the top stem joint, as in
the case of the Apiocrinida) and Comatuliv. At/iisKisocriiiiis, in its pedun-
culate younger state, had five well defined Infrabasals; but after losing its
stem, the suture lines became gradually obliterated by limestone deposit
upon the surface. The .same is the case with the basals of the monocyclic
Eilri'icnims.

Mr. Bather discriminates between Dicyclica, P.cudomonocyclica, and
Monocyclica vera.* To the Pseudomonocyclica he refers those forms in
which infrabasals are obsolete in the adult, but were represented in early life.
They endjrace most of the Mesozoic and recent Crinoids. and may be sub-
divided into two classes : (1) forms in which the infrabasals gradually
become anchylosed with the top stem joint, and (2) those in which they
were rcsorbed in the adult. In the former, which among other groups
include the Apiocrinidoo and Comatula), the new stem joints are formed below
the centro-dorsal ; while in the latter, which are typified b^' the Pentacri-
nida>, the top stem joint is the youngest joint of the stem. We shall
l)resently show that both these forms, although the infrabasals may have
disappeared, still retain the characteristics of dicyclic Crinoids.

Several years ago we discovered t that among the Pahi^ocrinoidea there
is a regular alternation in the arrangement of the successive parts below the
radials, and that the orientation of the stem is essentially different among
monocyclic and dic3'clic forms. We fotuid that the salient angles of the stem
itself, and the projections of the axial canal, are reversed in the two groups,

• Ann. and Mnff. of Nut. Ilisl. (sixlli scrips), Vol. V., April, 1890, p. 310.

t Revision, Part III, Section I, p. 7 (Proceed. Pliila. Aciid., Iss.'i, p. 239), with ii most nnfortunntc
transposition of terms, wliicli was corrected iu the appendix. Also 18SS, Proceed. Pliilii. Aend. j). 351.

THE CRINOIDEA CAMEKATA OF NORTH AMERICA.

and that the cirri, wliich in dicyclic Crinoidrt ore radial, are interrndinl in tlie
otiiers. By employing this rule wo were enabled, in many caHes whore the
infrabasals are hidden beneath the culuiun, to determine their presence. The
law of alternate arrangement of the succes.sive part3 i.s shown by the follow-

ing table : —

Dic^cllc.

Muiioc}'clic.

Hasals.

Interradial.

Infrabasals.

Radial.

Column. Exterior angles of.

Interradial.

Radial.

Sections of.

Interradial.

Radial.

Column. Sutures.

Radial.

Interradial.

Sides.

Radial.

Interradial.

Cirri, wlicn present.

Radial.

Interradial.

Axial canal.

Radial.

Interradial.

This law is only applicable, to its full extent, in species with pentangular
or pentapartitc stem and canal ; but we infer, from analogy of these forms,
that the circular stem, wherever it occurs in dicyclic Crinoids, is also practi-
cally interradial, and in those of monocyclic type radial. Our observations
were founded upon Palaeozoic Crinoids, among which we had met with no
exception ; but on applying them to Me.sozoic and later Crinoids, we were
surprised to find that in most of the so-called monocyclic forms the relative
positions of the column and cirri were reversed, so *hat they were exactly as
in dicyclic Pala;ocriuoids. Though universally con.sidered to be monocyclic
Crinoids, they were built on a dicyclic plan ; and this led us to inquire
whether all those forms might not be dicyclic, whose infrabasals were hidden,
or had existed in their larval state.

This seemed to be confirmed by another observation which we made
among certain Paleozoic forms. In some genera, notably in Gruphioctiiws,
which was originally described as monocyclic, the infrabasals arc so extremely
small that they are completely covered by the upper stem joint, and only the
basals are visible. These Crinoids are practically in the same condition as
Millciicrinus, Apiocriims, and Pciiiacn'mts, for the stem occupies the same posi-

[

MORPHOLOGICAL PART.

[

tion toward the proximal ring of plates visible in tlio calyx as that of M'tllm-
crlnits and Apiocriiiiis, except that in the two latter the .^pace above the top
stem joint is vacant, while in Gra/t/Hocriniin it is filled by very small iiifViil)asals
(compare Fig. 17 with Fig. 20 on Table A).

Small infrabasals are known to exist in the base of the Pentaciinoid genus
Extracriims, and de Loriol has discovered similar plates in two species of
Milkrurimts (Plate VI. Figs. 1 a, h, and 2 <i, I). Those of M. imhithiclijlitfi he
describes as follows:* "Jo distingue tres nettement, sur deux iiidividus,
cinq piJjces extrC'mement petites, Ti peine distinctes jl I'a'il nil, qui sont
logees au centre de I'article basal, chacune reposant sur le somniet de Tune
des carenes, dans une direction radiale, au centre se trouve, ime petite
depression qui forme le fond de la cavite. Ces petites pieces, que je
n'avais jamais encore observees, jouent evidemment le role de ]iii"'c'os infra-
ba.sale-s, mais il I'etat tout a fait rudimentaire." Similar pieces wore dis-
covered by him in his M. Orhiyiii/i, of which lie sa^-s : t " Kilos no pouvent
nbsolument se voir que lorsque, par un hasard heureux, I'article basal pent
se dogagcr du calice. II me paratt indubitable que se sont la do petites
pieces infrabasales rudimentaires semblal)les jl cellos que j'ai signaloos dans
le ]\[. polydacli/his."

Admitting these plates to be infraba-sals, it is certainly quite improbable
that other species of Milkrierimis having a pentangular stem, and those with
a round stem, and the species o£ Ajiiocriiiiis, — a genus which, according to de
Loriol, is very closely allied to Mi/kricniiiis and GiuilnrdicriiiHs — should hiive
possessed no infrabasals. In all species of ^lilkricrbius, the column, unless
it is round, has interradial angles (Plate VI. Figs. 1", 3, 4'', 5). oxiictly as in
M. Orbigiii/i and all dicyclic Pahuocrinoids ; and hence, if the genus wore not
dicyclic, this structure would be at variance with that of other (.'riudids. AVe
come to the same result if we examine the vacant space witliin tlie basal
ring. Tliis is radial, and disproportionate in size to the axial canal of tlie
stem, which is small and circular ; whereas if it represented the axial canal
of a monocyclic Crinoid it should be interradial. The space is largo enough
to have contained, besides the canal, additional plates, which, if present,
would have occupied the same position as the infrabasals of M. Orhliini/i.

The column of dicyclic Crinoids abuts either entirely against tlie infra-
basals, or partly also against the basals. Tlie latter is the case with the top

• Piilniiit. Frnm., l^" si'rif, .Viiiinnux Invprtt'bies, Terr. Jurassic, Tome XL Premiere Parlip, Criuoidcs,
Paris, lS82-lS8i, p. 553, Plate 110. Figs. 1 nml 2.
t Ibid., p. 5CG (Plate llfi, Fig. 1, A, c, </).

TIIK CRINOIDEA CAMKRATA OK NORTH AMKRICA.

Htt'iii joint of Mi//<ricriiius Or//ii/iii/i imd M. pul^ihaii/lus ; while in other species
of tiie Ai)iociini(lie in wiiieh in('nibasiil.s are unrepresented, tlie eolinnn
touches the biisals only. It rests against the onlcr (dorsal) surface of the
plates, whose lun'cr margins are bent up, so as to form an inverted pentan-
gular concavity, radially disposed. This cavity, which is occupied and
completely fdled by the top stem joint, is generally grooved nt the inter-
basal sutures, and produces upon the upper face of the joint five angles,
which lit into the grooves, and interlock with the ba.sals (Plate VI. Figs. 1 «,
1 1>, and <}). The outer edge of the joint at the uj)per end has also a more or
less radiid outline ; while its lower end follows the orientation of the stem,
and is intornuliidly disposed when that is pentangular.

We mention these particulars, because Carpenter, in criticising our gen-
eralization,* umlertook to prove by the angularities at the upper face of the
stem that in those species of the Apiocrinidso in which the stem is roimd,
the latter was radially disposed, and not interradially ; and that those
species, according to our own rules, were monoc3clie and not dicyclic. lie
overlooked the fact that the top joint rests against the turned up dorsal
(outer) siir/acc of the basals, and not against their inferior fucfs. The surface
to which the " centro-dorsal " is attached, rei)resents morphologically the
surface of the concavity for the reception of the column in PaUvozoic Cri-
noids ; the inferior faces are those which meet the infrabasals, and in 3f. Or-
hijiiyi and M. iioli/daclylus actually supjiort them, but in most of the Apio-
crinidiv they enclose a vacant .space. If this space was filled by infrabasal.s,
as we think it was in the young Crinoid, the columnar concavity and the
upper face of the stem would be in exactly the same condition as in the
Ichthyocriuidie, in which similar angularities occur on the upper face of the
stem 1 Plate II. Fig. 4i). The uppei face of the column in all Crinoids
adapts its form to the .shape of the plates to which it is attached, and if their
suture lines are grooved, it will be correspondingly ridged. We thus believe
that Carpenter misunderstood the structure, and that he overlooked our
statement that it is the longitudinal angles ulonr/ the column which alternate
with the proximal ring of plates in the calyx, and not the angularities or
ridges '/ /lie upper face.

In Itliiz'irriniis the condition of the base is apparently similar to that of
the Apiocrinidie. The genus, however, was described by Carpenter t as

• Ann. nnil ^rn7. Xiit. Hist , 'S\nnh, ISSG, p. 286.
t Cliall, Ucp. Stalk. Crin., p L>1G.

MORPHOLOGICAL PART.

monocyclic, and the iippernioHt stem joint an tlie lust formed pliite of tlio
stenj. But he seems to have ehiinyed liis opinion iifterwanlH, for in ii letter
to us, dated November '28, IS'JO, he writes as follows: -I have spent this
morning studying my material ol' Jt/iixocrimis, including some fre.-h spicinicn-'
which I found among my father's collection, and 1 conclude that you an-
right in considering the top-stem-joint as a centro-dorsal liUc that of Jl'iiu-
guflkrlum and the Apiocriniihe. It is, however, always the smallest. /. <.,
thinnest joint of tiie stem. Hut it is distinctly marked into five fcissie lor the
basals by radial ridges, and this is sometimes very apparent in the younger
individuals. See Chidl. Kep. Plate X. Figs. 7 and 8. It is more maiki d in
It. Ifiiii'iioin than m Ji. /o/o/riim. The pentagonal space in the centre. I'late
X. Fig. 5, is nothing hut the axial canal." He tlien continues; '' Ilif/ii/cniinx
is a very dilTerent form, with its very numerous thin joints at the top of the
stem (see Plates VII. and VIII '/), and I have been thinking for some time
past that it must be renmved from the Uourgueticrinidiv and made the type
of a now family. The ten arms, and the trifa.^cial articulation are idso good
characters, as the latter replaces the syzygies of lihizocriiiiiti."

Except in one point, we fidly agree with this. Kxamining Plate X of
the Challenger Report, wc fmd in Uhhocriiius the .space within the l)a-id ring
very diflerent from the axial canal in the stem joints (see our Plate \'I. Figs.
1(1, /'), the former being fully twice as large, and pentangular, while the canal
is oval. The space between the basals is radially disjiosed. as in the Apiocri-
nidii>, and we believe that JiliLvurrhiiis is also pscndonmnocyclic. Its structure
is altogether different from that of Itidhi/rrlinii^ and Il'incrlmis. which in our
opini(m arc true monocyclic forms. They have no centro-dorsal. and the
nppi'rniost joint is the last formed plate of the stem. The open spa<i' within
the basal ring is interradially disposed, and lias the form and size of the
stem canal.

Om- observations on the Apiocrinidiw led ns in ISSG* to the conclusion
that most of the Neocrinoidoa may have possessed rudimentary infral)asals in
their larval state. This rather startling statement was unfavoraldy received
by Carpenter, and severely criticised by him.t lie held at that time that
with the exception of Eiirn'iiii», Kr/riwrinns. }[iii-.viii!lc!< and Uiii/tirriiins, all Meso-
zoic and recent Crinoids were monoc\clic. His objections, however, did not
seem to ns convincing, and in Section II. Part HI. of the Revision, pp. 294-

• division, V.\H III., Sc .ioii I.. |i|). S, 71.

t Uibliogr. Noticps. Aim. nnd Mug., November, ISsO, p. lOS.

TIIK tKINOIDKA CAMKUATA OF NOHTll AMKKIt'A.

209, we assertc'il tliut not only tlie nmjority of Stalkid CrinoidH, but uho tlic
Coumtiilii', WLTo built upon thu tlicyolic plan, and probably liiid intralnisals
in their larval statu.

Tliu centro-dorsal at tlio Pcntaerinoid stage of tlie Conuitulo, as may be
seen by examining IMato VI. Figs. 18 and I'J, agrees cUwely with that ol'lho
Apiocrinidie. It is intenadially dispo.sed at the proximal face, and also at
the distal face, so that its angles correspond with the angles of the baoals, as
in those ilicyelic Crinoids whose infniba.sals are hidden by the column; and
even in its free lloating stage the eentro-dor.sal retains itH interrailial
position.

So strongly were wo impressed with the conviction that the Comatula)
arc dicydic Crinoids, — although no traces of infrabasals liad ever been
found by W^ville Thomson, the two Carpenters, Goctto, and otiicrs wlio had
exten-iively studietl the embryology of Aiitidm, — that we urged European
investigators to nnd<e fresh search for these plates.

It was therefore with no little .satisfaction that we learned from Dr.
Carpenter in July, 1887, that infrabasals, wlio.se existence we had predicated
upon paltDontological evidence, had actually been found by Mr. 11. Hiiry.
This important discovery was announced at the Manchester meeting of the
Briti.sh Association, and communicated by Mr. Bury in a paper on " The
early stages in the Development of Aiitnlon rosacea."* The jjlates appear in
the ciliated larva, and consist of three unecjual pieces, which in the Pentn-"
crinoid stage are fused together with the top-stein-joint (centro-dor.xal), so as
to form together with the latter one large plate, with five angles, radial in
position. One of the plates is smaller, and has but one salient angle, the two
larger one- having two, — a structure which suggests that the two latter may
represent a pair of ancliylosed plates. Three similar plates, but with a some-
what different orientation, persist throughout life in the Tchthyocrinida;, but
the smaller plate of Aiilnhm rosacea, if we understand Mr. Burj', is placed
anteriorly ; while that of the IchthyocrinidoD is directed posterioily (Table
A, Figs. 14 and 15).t

It is of considerable importance that the infrabasals of all Carboniferous
Ichthyocrinidic are coalesced with the top-stem-joint (eentro-dor.sal) similar
to those oi Aiilethn. In specimens in which the column has been detached
from the crown, the small infraba.sals generally adhere to the top-stem-joint

• I'liilosopliioal Transnclions of llin Itojal Socioty of liOiidon, ISSS, pp. 257-.S0O.
\ The oriom.ilinii nf Ihis plate was incorrectly pivcn liy iis in llic HcvisiDii, Part III. Plate 0, Fig. 23.
Since tlicii we liavc fDund out tliat it is located in nil Iclilhyocrinidre to the right of the posterior basal.

MOUI'IIOLOUIC'AL PART.

(Pliito II. Fig. 4 /'), being in hoiho ciihom porfoctly fuNoil wi(Ii tliiit plate (Pinto
VI. Fig. 11). Till' coiulitioii is tlie muiuo uh in tliu t\v<» cpeeies of MI//1 liininm
in wliicli iiifiui)iiNalH liave been recognized, and we coneiudo from analogy
lliat a i'lision of llio>'o platoH eventually took place in ail gioupH in wliicli llio
new Btein joints nre not formed directly beneatli llie calyx.

The caHC [» dilTerent among the Penlacrinidas in wbicb the now Ktcm
joints constitute the iii)per part of the stem. Of the principal genera wImlIi
iiavo been referred to this family, one — Kitnurimin — has small infrabasuls
persiHtent through life; wliilo in the other two — Pritfiicn'niiii and MiKcrliiiia
— no trace of them can be found in the adidt. The dicyolic natun- of
Peii/acn'iiiiH and i^fiidcrinm is indicated by the orientation of the ftem and
cirri, the angles of the stem in both of them being interradially disposed,
and the cirri radially. Hut what beeamo of their infraljasals ? That they
fused with the upprr stem joint, like those of the Ichlhyocrinidiu, need not
be considered in this family, as that would necessarily prevent the formation
of now joints at the top. They may have been resorbed in the growing
animal ; but it appears to us more prol)al)le, from palieontologieal evidence,
that the plates grailually diminished in size, and finally disappeared allo-
gethi-r in the group. The structure of the IVntacrinidic is very difl'erent
from that of the ComatuUo and Apiocrinida>, and it appears to us that Cri-
noids in which the upper joint of the .stem is the youngest, cannot be derived
fi'om those in which the top of the stem is fused with the infiaba.sals, and the
two groups should bo widely separated. The Apiocrinidic and Comatulro
which hive a centro-dorsal, — /. t'., in which the iniVabasals are fused with
the upper stem joint, — should be placed together with, or close to, the
Ichthyocriniilie ; while the Pentacriuidic, which in many points agree with
the structure of the Potoriocrinida) and P^ncrinidie, wo think might be safely
referred to the Inadunata Fistulata.

It is very singular that while in E.t/riicn'inis and Milucruvis the projections
of the open space within the basal ring, and the axial canal of the stem, are
radially disposed (Plate VI. Fig. 9), both are decidedly interradial in Piiita-
criiiiis (Plate VI. Fig. 8). This anomaly, if we may so call it, was regarded by
Carpenter * as a proof that our generalization upon the stem is not applicable
to the Neocrinoids. This, indeed, seemed at first to bo indicated also by the
orientation of the stem ; but Bury's discovery of infrabasals in the Comatula
larva changed the whole aspect of the case. The discovery of these plates,

* Bibliogr. Notices, Auu. and Mng. Nut. llUt., March, ISSC, p. 2S7.
9

THK CRIXOinEA CAMKRATA OF NORTH AMKRICA.

wliOHO preHoiico we had inferred from (he orientation of the hirval Htcni nnd
centro-dorHiiI, xhowt'd that our obnervntion nawt bo one of wide signifi-
cance. The aberrant »triicture of the canal in Pin/((criiiii.^ Hoen not invalidate
tlio law an we have found it, but niniply pointH to tlie exiHtence in Hotne
groups of transition foriiis iulerinediate between Mouocvdica and Dicyclica.
Sueii transition forniH inuHt have occurred at Honie time in the dcvelopinontnl
luHtory of the two groups, if one was evolved from the other. Winch form
is the older has not been satisfactorily proved, but the evidence of Palo-ontol-
ogy points to the Dicyclica as the ancestral type. In the Canierata the evo-
lution was apparently complete at nnd ijcfore the Silurian, but it is probably
still going on in some of the later groups. In the Pentacriiiidie, the diminu-
tive size of the infrabasals in Ejlracrimta may be the first step toward the
monocyclic base, their non-representation in Mcfucfimix nnd riHtacriiiiin the
next, nnd the change in the orientation of the nxinl cnnnl another important
step in that direction.

We have discovered a case almo.st parallel to that of the Pcntncrinidie in
the Lower Silurian monocyclic genus (r/i//i/oeriiiiig, which has a radial stem*
and an interrndial canal, except in G. Furux/ulli, in which canal and stem
both are radial (Plate XXI. Fig. 5).

Gl/z/i/ocriiiiis belongs to a series of monocyclic nnd dicyclic Crinoids, which
are so closely Intermingled nnd intinuitely related that it is extremely difficult
to separate them generically, and one is inclined to place in the same family
monocyclic and dicyclic forms. There is perhaps no other group so likely to
throw light upon the derivation of the Monocyclicn. The base of G////ilocriiiiis
has been variou.sly described as consisting of one or two rings of plates. Ilall
originally defined the genus ns having basals only, but a few years later
thought he had discovered within the bnsnl ring in some of the species indi-
cations of five additional pieces, which were also observed by Meek, and
called by him "sub-basnls" (Plate VI, Fig. 12). S. A. Miller described the
ba.se as consisting of but one ring of plates, but he included in the genus
several species with two rings. We described the genus as dicyclic in Part
II. of the Revision, but in Part III. placed it among the ilelocrinidaj, after
throwing out those species in which rudimentary infrabasals could be satis-
factorily traced.

• The nncleus of the stem in 0. dtradtirlglHi nnd 0. T)i/eri is ol)scurpIy prntnnptnlnr at the uppor end ;
the projppling edges of the joints, however, give it n circular outline. The axial canal in Iwth species is
sharply stellate.

MOHIMIOLOdlCAI. I'ART. C,^

Thf ciiHo of Ohji>ti>cnnm Furnxhclli is very rutimrkahlo. Tlio oiii'iiliilion
of the nivxw poiiitx to (i iiioiiocyclic biisu, tint' of tliu axial ciiiial It) a dioyclic.
Bosidt'H, tliL' M|iocit'H in cIoHt-ly ii-latoil to olluix in wliicli tlio raiuil in iiitt'i-
radial, and tliu Htuiii radial. It \n quite evident that the rule whii-h governs
the relatioiiH of the partH below thu bate doeii not hold ^ood in (i. Fonix/n/ii,
M Wfl And it in thu TohhII Htatu ; but \vu think thin pidveM nothing more than
that in tiiiH specieM the monocyclic Ntago waH as yet incompletely developeil.
It hIiouM be stated that while the aberrant canal of ^'. FiintshrlH is radial
throughout thu whole length of thu Htem, that of /'iii/umiiiin \h internidial
only ut the u[iper portions; it toon turua to circular, and wlieru thu cirru.i
venwls enter, it is an radially disponed a» liiat of Mi/arriutm,

Among the Ueteocrinidii', also, a strictly Silurian family, we find a variety
of traiiMilion forniM. In Kiiiovnnnii the H|)ecies from the Trenton group have
lurgu infrabasals, thonu from thu IIudHon liiver group tiuite ruilimentary
ones ; while in Xcinimiiiix and T(iiiii»cfiiiH.i the infral)usnlM are altogether un-
r"pru«cnted. Tho axial canal of Ilrlivcriims U radially diipo.scd, that of
Xmocrimia and TtimtucrlnuH iuturradially. The three forms aro very closely
related, and if we wore to separate them upon the structure of the base, it
would be to the exclusion of other characters of manifest importance.

The examples given indicate that there is a most intimate relation
between dicyclic and monocyclic forms, and that probably the latter were
deriveil from thu Dicyclica by n gradual decrease in size and final oiilitera-
tion of tho infrabasaU in geological time.

Blither believes with us that dicyclic Crinoids preceded the monocyclic,
but he states that so far as tho Fistulata arc concerned he has found nc geo-
logical evidence to prove it, at lea.st not among the Fistulata. lie alludes to
the llybocrinidso as being probably monocyclic, but he rcgard.^ the Iletero-
crinida) and Anoinnlocrinidiu as true Monocyclica. As to Ili/hocrinm, he quotes
the earlier part of thu Revision, in which we stated that rudimentary infra-
basals might possibly bo present in the genus. This supposition is not veri-
fied by further study of thu specimens, which show satisfactorily that no
such platus are represented. Ilt/hocnnus is a true monocyclic genus, as much
so as Ile/erocniiiis and Anomahcrinus. This, however, docs not exclude the idea
that all three forms may have been derived from the Dicyclica, and there
are good reasons to believe that it Avas so. Tho dicyclic psendo-cystid genus
Purocrmis is so intimately related with Ilybocrinm that it is doubtful if the
two should not bo placed in the same family. Close relations also exist

THE CRINOIUEA CAMERATA OF NORTH AMERICA.

betwcL'ii Miroen'niis and locriniis, and between OHaimcrinus and Ililvrocrinvs, —
dicyclic and monocyclic forms respectively.

While tlie evidence thus point- Ic the probability that the one group was
derived from the other, it is dillicult to explain the change in the orientation
of the stem. That the whole crown passed through a revolution of 3C° is
highly improbable. The clinngo probably took place in the body of the
stem, modifying its form to suit the condition of the ba.se. The stem is
round in most of the earlier Crinoids; but we find occasionally within the
same family quadrangular stems from a quadripartite base, together with
pentangular stems from a quinquepartite base, whicli goes to prove that the
stem, to .some extent at least, adapted its Ibrm to the conditions of the base.
In a similar manner intcrradial stems mr.y have changed into round stems,
and these into radial stems. This, however, does not explain the change
in the orientation of the canal, and that of the cirri. The latter are
directed to the auglos of the axial canal, through which they communi-
cate with the chambered organ.

The only writer, besides Bather, who has discussed the derivation of the
two groups i-< Dr. J. Walther,* who takes it for granted that the simpler —
monocyclic — form is the ancestral one. His arguments were suggested from
his study of the pentacriuoid larva of Autiihni, and are extremely hypo-
thetical. They are based upon his pecuuar interpretation of the basals and
infrabasals, which, as he now will himself admit, cannot be upheld since Bury
discovered infrabasals in the larva of Antahn.

C. The Radiak.

The term '■ radials " is applied by us only to the first plate of each ray.
All succeeding plates in a radi.-d direction, whether free or incorporated into
the calyx, are brachials. The name was given by Miiller to all plates up
to, and including the first axillary, and all pieces beyond were regarded by
him as armplates. The same view was taken by Roemer, de Koninck, and
other European aiithors. The American Palaeontologists applied the term
not only to the plates of the first order, but to all plates of the rays that take
part in the cal3x. Thoy distingiii.shed those of different orders as primary,
secondary, and tertiary radial.s, according to rank.

199.

• " Uutcrsucliungcn iibcr den Bau dcr Crinoidccn." PaliEontogrnphia, 180G, Bd. XXXII., pp. 180-

IHOKPIIOLOGICAL PART.

Miillcr's interpretation of these ])lates was somew lat modira'd by
Scliulize,* wlio assumed that tlic arms begin invariably witli tlic first well-
d( lined iirticular liicet. lie held that in Ac/iiiocriiiits and Il/iiiilnciiiiiix, whicli
have no articidation above tlie (first) radials, the arms commence above the
first axiUary; but that in Critioids in wliicli the rays are IVeo above tlie first
plate, the arms begin witii tlie second plate of the ray.

Zittel,t who accepted Schultze's views and applied them to the later
Crinoids, describes Enrnims, Pciilncruins, and Mil/cricriims with one radial
followed by two brachials ; A/iiorriitiifi, however, with three radials. He evi-
dently supposed that in the latter the first articulation occurred on the axil-
lary, which is not the case, as shown by Carpenter, | who found in several
species of that genus nt the upper face of the (first) radial a transverse ridge
with muscular fossie above it. A similar structure, he believes, exists in all
Apiocrinidii', perhaps with the exception of Oiivtfanlicn'niis, which, iicoording
to de Loriol, | has no articular facets on either of the three " radials," nor
even on the distal faces of the axillary, so that it, cannot be determined in
this genus what plate of the ray bears the first facet. This shows that
Schult/e's rule does not readily apply in this group. Still more serious dilli-
culties arise among (he Pahcocrinoidea. In most of the Cainerata, all plates
of the calyx up to the top of the distichals, and often much higher, are
closely and immovably united, and the lowest articulation or mobility occurs
at the base of the arms.

Applying Schultze's definition to the Camerata, it is quite evident that all
the plates of the dorsal cup in a radial direction had to be called radials,
and not merely tlmso up to the first axillary. This we did in our earlier
writings ; and instead of making the lower facet the division between
radials and brachials, we took the calyx for the boundary line, and referred
to the radials all plates of the rays which take part in the calyx, and to
tlio brachials the plates of the free arms. We thus recognized among the
Camerata an indefinite nutnber of radials, while their number was reduced
in the Inadunata to a single ring of plates, a course which was afterwards
adopted by S. A. Miller, S. II. William.s, and Prof. Worthen, against Hall,
Meek, and others, who included in this group the first order of brachials.

The Ichthyocrinida^ in which the lower branches of the rays take part

• " Moiingrapliic ilcr Kctiiiiodcrnicn di's Killrr Kiilkes," 1S60, Wicii, pp. 5 uiul 9.

+ lI.\ii(ll)uoli (Ut rnlirmilii1o<»ic, Vol. I., p. X\9.

t Ann. an Muf;. \at. Ui>t., St. C, Vol. VI., p. 12.

§ " Tiilec utuluglu Frau^-aisc,Jurassi(pic," Tumc XL, Tt. I., p. 215.

' I ;

THE CKIXOIDKA CAMKKATA OF NORTH AMKKICA.

ill the calyx, wore trcntod by lis in tlie siiine way as tlie Camenita. Scliiiltze,
however, described 'Ttuocn'iiiis as having but one radial, in which he was
correct from his standpoint, for the siicceedin;f plates seem to be united
among themselves, and with the radials by loose suture or a sort of rndiinen-
tary articulation. Carpenter described I'aihuriiuDi and the Coinatiilaj, which
are in a similar condition to the IchthyocrinidiJC, as having three radials in
all cases, whether the })lates are enclosed by perisome or not, and he distin-
guished the rami as primary, secondary, ami terti ;vy arms. According to
him, lUiisiicrliius Jfiiiviniu, with ten arms, has three radials; while Ji. h/oliiim,
liive Ciipirssocrliiiis, Pmcniins, and all Crinoids with but five arms, have one
radial, followed by brachials. He thus made the second plate of the ray a
inrninl rwliiil in the former, and njirft bfKchlal in the latter, giving to part.s
which are undoubtedly homologous different appellations, while distinct parts
were thrown together. The methods of treating these jdates heretofore
adopted were not only empirical, but inconsistent with the principles of
morphology ; and the want of luiiforinity among the difierent writers,
respecting the terms, must have been perplexing to the student when con-
sulting their works.

In 1881,* and again in lS85,t we exprcs.sed the opinion that the arms
fundamentally begin with the second plate of the ray, and that all Crinoids
have but one ring of radials. In support of tiiis we stated that only the
lower ring could be homologized with the oculars of other Kcliinodernis ;•
that in the simpler form — tlie Inadunalu — the arms were free from the
(first) radials, and that in the remaining groups the lower arm plates were
incorporated gradually in palacontological time. We refrained, however, at
that time from changing the terminology, finding it convenient for purposes
of description to continue the old terms,

Or.r interpretation of the plates was accepted by Caijienter in 1884,]:
who confirmed it Ijy the developmental history of the plates. The "outer
radials," he says, " commenoe as imjierfect rings, which soon become filled up
with lengthening fa.«ciculated tissue, just ns is the ca.se with the stem joints
and later brachials ; " but " the /;•»< radials, like the basals and orals, com-
mence as expanded cribiform films." TTe further alluded to the f.ut that the
.«o-called primary radials of Mcfacn'niis are pinnule-bearing, — a thing which
wc havo observed in exceptional cases among the Poteriocrinidte also.

• Rpvision, I'nrt IT., p. 10.

I Clialieiigcr liop. uu the Stalked Crinoids, p. 4S.

t Ilmi.Rirtlll.p. 12.

MORPHOLOGICAL PART.

Upon commencing the present work, we had an interchange of views
with Dr. Carpenter as to the best plan to be pursued respecting these plates,
especially as to whetlier it would not be better to change their terms, which
we considered meaningless from a morphological point of view, for others
more appropriate. We proposed to restrict the term " radi;ds" to the first
ring of plates of the rays, and apply to the succeeding ones the terms " pri-
mary," " secondary " and "tertiary brachials," according to their rank, in
all cases, whether the plates were free or not. lie replied that he appre-
ciated the great advantages of the proposed nomenclature, and was willing
to adopt it in principle; but he thought the terms "primary," "secondary,"
and "tertiary brachials" were too long and cumbrous, and he proposed in-
stead of them the terms " costals," " distichals " and " palmars," respectivel\- ;
which we finally agreed to accept. Carpenter announced our agreement
in a paper " On certain Points in the Anatomical Nomenclature of
Et'hinoderms." *

In the earlier Inadunata and Articulata, — not in the Camcrata so far as
observed, — the radials are frequently compound, /. c, constructed of two
segments or parts, which are closely united b\' a hori/.oiital suture, and in
the organization of the Crinoid count as one plate.t Among the Fistulata,
compound radials are found in the Ileterocrinidaj, Anomalocrinida% Ilybocri-
nida) and Dendrocrinida;. In some of these families tliey are restricted to
the right posterior ray, in others they occur also in other raj'-s. We know of
no case in which the compound structure extends to all five radials, at least
two of the plates being always simple. Among the IIeterocrinida>. as a ride,
the right posterior, and the right and left antero-lateral radials, are compound,
— exceptionally the anterior one in place of the left antero-lateral; — wliile
Aiioimlocriiiits and Ohiocrinm have but two, and loerimts, Merocriiwn, Ifi/Ztocniiiis
and Il'ipfocrmis only one. It is further worthy of note, that when there are
several compoun<l radials, the corresponding psirfs are of nearly equal size;
while the segments vary considerably among themselves in the different
genera. In JIf/crorriwi.i, Ohiocriwis, lorriinm, Mcrocn'niis. Ilf/hocniiim and Ihjlin-
C'/stis, the lower portion, — the so-called inferradials, — are considerably
larger than the upper or superradials. In Aiwimilocriniis and Dciulrocrmis
the two plates are of nearly equal size; while in Ecfr.inrn'iins (TTc/irocriiiii/t)
siiiiji/cx the upper ones are three or four times as large as the lower. In

• Aim. .and MnR. Nat. Hist., Spr. fi, Vol. VI., pp. 11-18.

f \Vc fiuvc n full (loscriplic'i of tlirsc pliitcs ill a paper "On the Pcrisoniic PIbIcs," Pmcecd. Arad. Nat.
Sci. riiiln., October, 1890, pp. 378 and 379.

THE CRIXOIDEA CASIKRATA OF NORTH AMERICA.

Ammuhcnima the left posterior rniliiil, wliicli is the hiryest phitc in the calyx,
is sometimes bisected loiigitiuliniilly, but this is not oonsttmt.

The gmdiiul increase in size of the upper segments, and the disnppcnrnnce
of compound plates in other rnys than tlic posterior, indirates that in those
Crinoids tiiere is a transition from three compound plates to one, ami also
from compound to simple plates ; and we think it may be safely assumed
that there was a time in the early history of the Crinoids when the arm-
bearing section was altogether unrepresented. This was apparently the case
in Bdnvcn'iiiis, in which two of the radial plates are non-arm-bearing, and as
these plates occur in the same rays as the compounil plates of AnoiiKil'icrijiiri,
we may infer that Bitcrocrinun is the ancestral form, lower in its development
than either AiioiiialiKrinitu, IlnplocriiiHS or Licriiiiin.

The later Fistulata have no true compound radials ; and although the
lower segment of the posterior radial is still represented in many of them, that
plate does not bear the same relation to the arm-bearing plate that it did in
the earlier forms, but a.ssumcs the functions of an anal plate. As such, it will
be considered by us in its proper place.

Among the Larviformia, true compound radials occur in Ifn/ilocriiiiin, which
has three of them : in the right posterior, and the right and left antt'ro-lateral
rays, — the same rays in which they occur in tlic IIetcrocrinida\ The com-
pound plates of the Ichthyocrinidaj will be discussed in connection with the
anal plates.

In groups in which the radials are simple, the five plates are approxi-
mately of the same size ; but when compound, they often dificr considerably
in size and form. Tiiis is most apparent in Calccocriiiiis, CutillocrliwK, Iln/ilvcii-
iius, and I'l'^ovn'mis. Among the Poteriocrinidie also, when the inferradial is
represented, the right posterior one is smaller than the others, and of some-
what difl'erent form. In some Palacocrinoidea, the radials are separated by
supplementary plates ; while in all later Crinoids, with the exception of the
recent genus Tlummdlomnm, thoy are in contact all round. In the Ithodocri-
nidtc, and curiously enough in T/iniiiiiK/ncriinis, ih('y alternate witli large inter-
radial plates, with which tliey form a ring often pieces. In the Thy.sanocrinida\
Actinocrinida>, Batocrinida;, Acrocrinidic, Dichocrinida^ and in most of the
Fistulata and Ichtliyocrinida;, a special anal plate is interposed between the
two posterior radials. In the Reteocrinidre, they are separated by numerous
small, ill-defined plates at the four regular sides, with the addition of an anal
plate at the posterior side. In the Melocrinida;, Eucalyptocrinida-, Platycri-

MORPHOLOGICAL I'ART.

nicltr, and in a few of the later Fistiikta, all five radiala are in contact
laterally.

The radials, both among each other and with the basal«, are united by
closo Hiituri', the apposed faces being generally smooth, but occasionally
wrinkled or striated.

D. T/ic Amis and Pinnulea.

Admitting that the arms begin with the first plate above the radials. all
plates of the rays, from the second one up, are brachials. As before stated,
we adopt the terms oostals, distichals, and palmars, for the first, second, and
third order of brachials, respectively. When there are further divisions in
the rays, the plates are designated as postpalmars, or, when greater detail is
required, as brachials of the fourth, or fifth, order, and so on. We also dis-
criminate between fixed and free brachials, meaning by " fixed " that the
plates so designated take part in the formation of the calyx, and by " free "
that they do not.*

• This is a slifrlit modilicaiion (if the plan proposed by Cnrpriitcr, who reserved tlie term "/rrt- hm-
«■/}«//»" lor the plates of the '.L-nniiialhraiichcs aliiiif. lie also dill'crcd from lis in oalliiii; the postpalmars,
when there are more ihau four bifurcations to the niy, " jiosljialmnn of the lirst, second, or third order "

KXIM.ANATION OF TAULK B.

TlIK I'l.ATKS OK TlIK KAVH IN DIKFKUKNT (iKNKllA.

1. Pnrl of rav ol' -'/((/•.v«/HorW;/H.< ; iiisliils, ilislicluils, liibl uiiil secoiiil imliniirs — (if the liitllT only those of

the two outer sides of the mys — abiitliii),' iigiiiiist the miliiiU.
i S,-aphiiirriim». Anns imiseriiil ; |iiiiimlat<(l ; (lii'holoiiiiziiiif; tlic joints pinienlf.
:t. Ileli-mim-riiiiii li/inn'. Anns \i.,i-<-iiai, triviii^' nil' armlets at inlervals,
I. A lay uf IWiivioi-riiiMi IVhilJiflili. Arms liiserial, br.incliinB ia the free state.
.-). Troxiuuil (lart of a rav of Sl»)ii,ioi-n,iu.i urii/ji/iin. Arms biseiial. given uir alternately I'riim opposite si.les

(if Inlnilar appcnil:n,'es.
fi. l'rox:'i.(l par; of a riiy of Crntdlm-riiim pulfher t Hiu h'wer l)raehial» arran),'('il »s in Fi|,'. I.

7. I'art (if ray -f < hii/^'/ioc-hiiiM niiiiii/om. Arms uiiiscrial ; the main hrauehes giving olV branehlets in

tlll^' rs.

8. r.. !• M'(rl.ou of rt ray of Slmlo<;-i,iH« recalls. The arms given off from the proximal plate al a'.Lcrnfttc

mli^ «ilhin the calyx.
•i. Simhiitli:- ''.IIS U'lirhmniilhi. Arm- iiniserial, eomposeil exelusively of oostals ; the joints nrrnngril

aarulU I
'l\- ! !;. uiag symlwls arc used in the ligures : 11 =. radials ; I = primary bmohials or eostals ; II =
seconchry b, ■■ -mI. or distlchals ; III = lerlii.ry brachials or palinars ; \\ ~ fourth order of braehiids ; V ^
•'iuhordi-r .'''-Mehials; amission; i> = |iiiniules ; a. = armlets.

MORPiior.o(;icAL I'Aur,

TABLE U.

TIIK CHINOIDKA CAMKKATA OF NUKTU A.MKUICA.

'I'lio iibovo terms wliicli wi'ie acci'|iU'(l \ty Mr. IJiitlicr in 1890,* ami used
in liis t'liilior [lapLTs -Om tliu Diilisli Fossil Ciinoiils, were in Jiimiary, IS'.t'J t
aliiiiiiliiiiL'd l)y liiiii and MubsUttitud by ullieis. llu .stated tiiiit ho iuuiid
cirtain dilliculties in ilioir applicatiuii tu I'ala'u/oiu I'unus, and prupuMud in
plaoe of tlieni liio followinj^ terms : —

I'l'iiiiibi'.ii'lis = uiir iii'iiiiaiy bracliiuls, ur CuiitalM.

J''iist piiuiiliiiii;!! = •' first co.stjil.

" SUCOIIll CO.still.

'• axillary cDstiil.

•' si'conilary luiu'liials, or Disticlials.

•• axillary (ilsliclcil.

•• tttrtiary bricliialn, or Talniars.

•• bracliials ol' tin' I'ouitli ordor J

•' brachials of tin' liltii onlcr > rustpalmars.

'• brachials ol' the sixth order )
Ktc.

•Si'i'diid laiinilirach
rriniaxil
Sii'iMidil)raohs
Si'i'\iiidaxil
Ti'rtiobrachs
(jiiai'lihraidis
Qiiiiilibr.\udis
Si'Xtibrachs
Etc.

Tills nomeneiatiiro \n based upon tlie wnnio principle as onr own, and
even tlic names are not so very dilTerent eonsiilerinj^ that the terms "cos-
tals, " " distielials," and •• palinais" are proposed as etpiivali-nts ol" •• primary,
seconilary, and tertiary braeiiials;" but liatlier propo.sed tlie.so terms for liie
pinnuleless forms only, and broiiojit out anotlier terminoloj,'y to be applied to
pinnule-ixMirinj^ arms, viz. : —

Munostidials (First Order).

First iiiDiiostidial.

Scc()i\d nionostirhal.

^runaxil (First .Mainaxil).
l>isliclials (Second ( Irder).
Di.staxil (.Seciiiid Mainaxil).

Tetra.stichals (Third Order).

Ti'traxil (Thinl .Mainaxil).

Uctastifhals (F.mrlh Order).

(Fifth (trder).

(Sixth < >rder).

Tiiat tlio l)raneirm<? of pinnulirorou.1 arms, na supposed by Hallicr. is
almost quite rej^uJar, is i)y no means tbo ease. We fre(|uenlly find among
Camerate Crinoids rays witli three, five, six, seven, nine, and ten arms,
instead of two. four, or ciiilit. In S/rotorriims, there are lays \vitl>. tisirty
arms in tiie calyx, and tiie " Kinials," wiiicii here conii)iise tlie plates
of tiie free arms, altliouj^li j^iveii ofl" from the finirlciiilli axillary, are
"Triacoutasticlials.' .Still inoie complicated is the case in i</'i/<iiitic'n)iiis,
Eiiclnilii-ninix, ni/iithicrliiuH, and Mi/ocriiiiiif, in which, to the full length of their
rays, from the costals or disticlials up, the brachials are developed into rigid

* AiHi. uiid .Mag. Vol. V. p. 313. t H'iJ- Vul. I.\. |i|i. .Jl-(il,

MORI'll()H)(;iC'AL I'AUT.

cnlyciiie tubcM, and tliu original piiimilos into iiltLMiiiitfly aniingud |iininile-
bfiiring arms. This hIiows that tlic st-cond imit of Uallu-r's It'iiiiinology
ciinnot l)t' citnit'd out pnietinilly, and we sue no good ix-aMtn wiiy thr lornier
turins coidd not he uxuil tor all Ciinoids, ]iinnnhilo or non-|iinnuiute.

The coslals of lh<; C'unu'rala. as ii rule, consist of two philcs to thi' ray ;
I'xcoptioinilly of oiii' or threi-. J'tiili/viiiiiin has <,'i'ni'raily hnt oni- ; hut two
of its oarliur spocics have two, ami it is (piiti' proltahie that tlie genns ori;:i-
nally had two costals, which later on were united into one. This ^<eenls to
lie conlirmed hy the fact tliut some of the species liave tiaiisverse grooves at
the dorsal face of the plates, and that in inultii)ra('hiale species, the <lislichals
and succeeiling onlers are composeil of two pieces. Slifnivriinis al.^o has liut
one costal, which has llu! pro])ortions of the '■ondiiued first and second plates
of /)ii/ii/ui n'liii.t, with which it has very dose alliiiitii's. 'I'he same >iruclure is
found in Aii//irmt>iTiiiiis and llnilninliinK. Diclutrrtinix iuis two costal.s, which
form a sy/ygy, the epi/.ygal supporting an arm. The allied Tn/iininiini.s ami
J'/irn/nniiiiis, however, iiave lint one. in /ln/nrriiiiix. iuu\ in most of the Hato-
criniles. the fnst costal is very short, aiul is frecpiciitly anchylosed with the
Hccoiid in one or moie of the rays. 'I'hree costals occur among Camcrate
Crinoids only in /{i/nifiuiiis Kl(ll(tri'<, and in Hall's imperfectly known
Hclilxiicriiiiix.

Among the Articulata the nund)er of costals is more variahio, anil ol'leii
dilTers among the rays of the same individind. FnrhisiiinliiuK A»/(i-^n:i* may
have two or three costals in all its rays, or lour only in one or two of them
Cii//ii"rriiiiis and Min/iilonuniis have? two, Ichlliiiin'rlniis anil Tii.viiviiiins two tc
tliree, and AiiiKorriiiim hnt one ; wliili! Oiii/ilinrriiiiis \m-i from three to six.

The numher of costals is still more varialile in certain groups of the
Fistiilata, in some of which such irregularity is the rule. This is the case in
Ci/ii//i<>i-i-ini's and I'drisnrriiiiis, in which one ray may have two. the adjoining
one three, and the next perhaps five or six. Cinlinrriiitin has two to three,
A/ekn/iicriiiiis from two to .-^ix. I^ess variahle among the rays, hut still nuinor-

• UV are of llir (i|iiiii<iii thai For/zrai'iiriiniK iiiihilh. di' KcmiiipkN Ivpc iif tlii' i;'""-. i' !.'"M(iiiiill,v idiii-
lic:il Willi Oiiyi-iorriiiMn l.voii. We rid'iillv (ilil.iincil rioiii 'rMurnai, lli'l|,'iuni, n llni' s|HciiMc'ii with iiriiis,
wliicli I'lcarlv slums llial il lins a small anal liilir iTstiiii; iipnii llw fiisl anal \ihlr. Tlie r»\;\ arc fivi- aliovr
ihr llist ('(Hliil, and aro rxtrcnu'lv licavv Id lln' fonrlli (li>liclial, whrnco llicy hranoli iiir iiili) minicidns small,
ciirvini; arnlrls, i\arll_v as in (hiyrhorriiiiin i:iyrii//i/ii^ I,vi>n. Di' Kcininck slalcil llial in liis species llic
pliilcH 111" the anal side, wliieli were imperferllv sliown in Hie spi-einiens, were priilialilv mure nnmemus llian
lliDse of the iillier siili's, wlierens llie fael is the opposite ; ami \U\- slaleim .1, no doidil. led Hall and others
111 ri'lVr /'./■*,■</;„•,■)//«» Jfliisfhi and allied forms, in whieh that aetnallv is the ease, to de Koiiiiiek's Kenus.
If, therefine. ile Kmiinek's type is that of Oiii/.-lim-riiin'. the latter iianie may have to be abandmu'd, and
B new Ki'iierii' name proposed for sncli forms as /'. .l//iiA.ii:i.

I r

THK CHINOIDKA CAMKllATA OF NOUTII AMKUICA.

Oil.", ail' tin' CDstals {){' Dciii/rnrriiin.i mid llnmnvninis, in wliicli wt' liiive roiin I'd
iiM iiiiiiiy a^< M'Vi'U ; loirimia lias four, Aii"m((t"cniiiix IVoiii two lu lour in flio
Hunio spt'fii'H. Mont of tliu otlior Fi.-ttulatii have one or two. Wlicii there is
but oiif |)lali', it is gi'iieially twice an long an the two, tlie hitter fonuing
a H^z.vgy. We liiul this in the majority of the I'oterioerinidii', except in
the iiiiteriiM' ray, which in some species has as many as twelve costals. while
in Dtiiers it lias no liiliircation at all, ami the arm is eoiiiposeil oi' costals only.
A lew of their species have Irom five to eight costals in each ray, anil I'ulifi-
ovrinm iiimoiiriiiinix from ten to rourtecii. In the Ilyliocriiiidie. and in tin-
Larviformia ns a rule, the nnns ure formed exclusively of costals (Kig. 1);
and only occasionally in .li/'ii/ivriims, in one or two of its rays, the radials
are axillary and in the ahseiice of costals support two rows of distichalH.

From these facts it is obvious that the number of costals does not consti-
tute a reliable character for classification, as heretofore HUpposed, and that in
some groups their number is of but little value for specific distinction. This
is oven more markedly the ease with rc-^ard to the higher divisions of the rays.

'I'lio disticlials are borne upon the axillary costal, which splits the ray
into two divisions, and all succeeding bifurcations take jtlace from one or
both of these divisions. To this rule, however, there are a few exceptions:
Sfi't/aiiocriims Kcitl/t/im, a few species of Milncriiiiis, I/i/nrnniis and Citlaiwivr'tuim,
have no re'/ular <listicliy, and all their branches are given off from one
trunk. A similar structure is Ibiind among the Poteriocrinidie in the pos-
terior ray. In most of their species with two arms to the ray the jiosterior
ray has but one trunk, and in multibrachiato forms the first bifurcation of
the posterior ray corresponds with the second in tin- other rays, nraiiching
takes place either alternately from opposite sides, or by means of dichotomy.
The former is very froiueritly the case among the Canierata. and is the rule
in the Actiiiocrinidiu.

The arms are composed of one or two rows of plates. The iiniserial
nnns arc composed of either rectangular or cuneate plates, the former being
the most archaic form. The cuneate plates arc alternately arranged, and
gradua ly pass into a biserial arrangement. Arms arc called '" biserial "
when the plates interlock, and do not reach to the full width of the arm.
This exjjlains why in biserial arms the pinnules are given off from every
j^lato at each side of the arm, while in uniscrinl arms every second plate at
each side bears a pinnule.

That the biseriol arms represent the higher form is clearly shown by

MOHl'IlOLOdlCAI. I'AUT.

71)

thoir mode of growth, iiiitl tlioir griuliml introduction in guologiciil tiine.
In tlie young dit'yclic Crinoid, tin wtt liad occasion to ob.-^crvt' I'lpiMiiilly well
in tho genus yv.<///o////'.v (I'latt- fiXXIIl Fig. 10, and IMatu LXXV. Fig. II),
tlio arms ari> unisorial througliout, their outlines waving, the plates deciijediy
wedge-sluiped, tliu |)innules proportionally largo (.nd gison od" alternately as
in true uni.serial arniH. in xomewhal older npcc'inuns, the plates at the tips
gradually interlock, an<l tliu new onuM Htill forming at the di«tal <'nd are
strictly l)iserial. With advancing maturity the interlocking gradually ex-
tends to the prt)xiiuid ends, luitil (iiially in the adult I'/ti///cniiiix the whole arm
becomes hiserial, excei)t perhaps as to a few plates near the calyx, whicli
permanently retain their larval condition. Similar modilication-< occurred
in geological time. In the Ijower Silurian the nrms of monocyclic Cainerata
arc uniserial, almost without exci'ption. In the Niagara group and Wen-
lock limestone, however, they rapidly change into hiserial. It is very signi-
ficant that among the species of that epoch we find as persistent characters
all the phases through which the arms of the individual Crinoiil pass in early
life. This is well u in the case of the IlatocrinidiC* The arms of

llulirorriiiits and h lueiiiiiis are uniserial; but while the jdates of the
former are always rectangular, those of the latter in sonu> species are de-
cidedly cuneate. The same modifications can be observed among the arms
of rulilll'icrmis and Sfi/iiliiuriiiiis, but in 8ome of their Hpecics the cuneate
plates alrea<ly begin to turn into biserial by interlocking. We thus find in
the same genu."*, anil almost contemporaneously, all the variations from uni-
serial arms to biserial ; and, what is most significant, the arms of all r)evo-
nian and later Uatocrinida> are stri(\tly biserial. Turning to the I'latycriuida',
we find that the Upper Silurian C"rif///i'Cniiiis has nni.serial arms, foinied of
rectangular or cuneate joints, while in Jfiirsii/nocri'iiiin, Ciiiicocfinii.s, and I'/n/i/-
crlniis they arc biserial. We may note also the case of the Ilexacrinida', in
which the development of the arms took place at a later period. The arms
of the Devonian genus IIi.racniniK are uniserial, and also those of tlu' earlier
species of Dirhorriinix. The plates of the latter are rectangular in all Kinder-
hook species, and al.-JO in about half of those from the Burlington and Keokuk
groups ; in mo.st of the others they are wedge-shaped, and ir a few of them
the arms fairly enter the interlocking stage. All species, liowever, of the
Kasknskia group have bi.serial arms, and likewise the contemporaneous
Tdlnrocfiniis and Plcrolorrimis. Among the Melocrinida;, GlnpiocriiniH and

• Wf linvp scpnnitod the lliitdcriniilH' from thi,' Actiiiopriiiidir, rcfiTrliig to llirin only (liosc genera in
wliich tlie niiiil |iliti' is followed liy llirec iiitcrbrachiiil pieces, iiisleiul of two ns in the liilirr family.

IMAGE EVALUATION
TEST TARGET (MT-3)

1.0

1.1

1^ l&i 12.2
2.0

■u

1.25 III 1.4

^^^^

^>'
•^

Photographic

Sciences

Corporalion

"'t?* ^
^^V^

23 WEST MAIN STMET

WIBSTM.N.Y. USIO

(7:6) S73-4503

.<*•

\^>^

^
►^

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

>. %

Compsocriniis, — both I'rom the Lower Silurian, — have uniserial arms; Pm-
i/li/ptocyinns, and probably all later Melocrinidaa, biserial. Among dicyclic
Canierata, we find well defined biserial arms already in the Trenton and
Hudson River groups, aK)ng witii uniserial, the former being perhaps in the
majority ; but the latter are continued to the lower part of the Devonian by
two species,* and these, together with the species of Dichocrinus, are, so far
as we know, the only representatives of the Camerata with a single row of
arm plates that survived the close of the Silurian.

In the Fistulata, the biserial arm structure was introduced just before the
close of the Carboniferous, but only in a limited way. True biserial arms
only occur in Gruphiocfiiws,-\ Euixichi/criims, Cromi/ocvinus, Hi/Jreionocnnus,
Emoerinus, Stemnvdocriniis, and IJncriints, but the majority of species have
either quadrangular or cuneate arm plates, and in some of them only the
tips of tlie arms begin to interlock. In this group the biserial stage at no
time became a constant character, not even in the Triassic. Encrinus lilii-
formix has perfectly biserial arms, while the arms of Encrinus gracilis are
uniserial, and composed of quadrangular plates.

Tiie arms of the Articulata, not only in Palaeozoic pinnuleless forma,
but also in the Neozoic pinnule-bearing ones, are uniserial without exception.

The pinnules, as happily expressed by Carpenter, are repetitions of the
arms on a small .scale ; and in their organization morphologically, and to
a large extent physiologically, closely resemble ordinary arm branches.
They are short branchlets given off along the sides of the arms, but ra'-ely
reaching their tips, and are usually more slender, and composed of longer
joints. The pinnules differ from arms in containing the fertile portions of
the genital glands, while the arms lodge the genital cords. Like the arms,
they have ambulacral furrows fringed with cilia, by means of which particles
of food coming in contact with them are carried along the grooves to the

* Oelilert's new genus Viameiiocrinus, nnd " Rhoilorriiiu.i " gonatoies Miiller (bolli from the lower
Devonian), which perhaps belong to one genus, linve diehotomizing arms, composed of sliort, quadrangular
plates.

f It is doubtful if the name Ornpliioerinus can be retained, according to the general rules adopted by
naturalists, as it was incorrectly dclined by deKouiuckaudLeUon. The type has small infrabasals hidden
by the column, and the position of the anal pinte is materially different from that given by the Belgian
writers, which probably was not known to Trautschold when he proposed the genus Phialocrinns. The anal
plate of Graphiorrinits enrriiwitlfs, dc Koninck's type, rests directly upon the truncated posterior basal, as
we observed in a fine specimen in our collection, exactly as in Phhloerinua. Tliere is, however, a slight ob-
jection to Trautseliold's name, which was preoccupied by Eichwald (Lethaia Rossica I, n. 578), but the
genus was founded merely upon fragments of column. That Phialocrhus jm/eits has two costals, and Oraphio-
criniis enrrinoides but one, may not be of generic importance, as the two plates of the former are equal to the
one of the latter, which evidently form a syzygy.

MORPHOLOGICAL PART.

mouth. In their normal condition the pinnules are arranged alternately on
opposite sides from every second joint, so tliat each joint bears a pinnule.
When the interval between the pinnules is greater, wliich is frequently the
case at certain parts of the arms, especially among recent Crinoids, this has
been called a syzygy. The term was applied by Joliannes Muller* to
the immovable union of two arm joints, of which only the upper one is
pinnule-bearing. The two plates, to which the names " hypozygal " and
" epizygal " were given, — the Ir.ter for the pinnule-bearing one, — count in
the alternation of the pinnules as one joint. Their apposed faces are not
necessarily striated, as indicated by Muller, being sometimes dotted or
smooth. Smooth syzygial faces have ' een observed in recent Crinoids only
in a few Comatuloa, but they occur quite frequently among Palaeozoic species.
In the latter, we also find occasionally a succession of two or three hypozygal
joints in the same syzygy .t

Syzygies do net occur among Palaeozoic Crinoids at irregular intervals as
in recent ones. Either they have a continuous series of syzygies through-
out the whole arm, as in the Hoterocrinidas and a few genera of the Came-
rata, or there is one syzygy in each order of brachials, which is formed
by the two proximal plates. The latter is frequently the case among the
Poteriocrinida), Encrinidae, and also in the Camerate genus Dkhocriiins. In
Dtchocrinm, the suture between the syzygial plates is very close, and the line
of union more faint than the lines of adjoining pLates. In the Poteriocrinida}
either the apposed surfaces are flat, or the hypozygal plate is slightly ex-
cavated, and the epizygal correspondingly convex. In Encrinus liUifonuis the
corresponding faces are dotted so as to make a very close union. Tlie Poterio*
crinidaB may have one or two costals within the same genus. In species with
two, both plates together take the form and size of the one ; and this rule
applies to the proximal distichals as well. That the two plates of the costals,
as well as those of the distichals, form a syzygy, is practically shown by the
pinnules, which in species with but one costal begin with the first plate after

• Ucber den Bau des Pentacrinus caput inedusne (Abhandl. d. K. Akademic der Wissenseliaften, Berlin,
1843, p. 315).

t The term " syzygy " lias also been used by some writers for (he immovable union of the nodal stem-
joints with those next below them, as in the case of Pentacriiim. Tills, we think, is not in accordance with
Miiller's definition, who proposed the term for two arm-joints of which only the upper is pinnule-bearing,
and not for a special mode of union between plates generally, lladiated and dotted surfaces do not always
imply a syzygy. Such faces arc found among Palaiozoic Crinoids very frequently on the ordinary arm plates,
and even, as in Crotalocrinm, between the plates of the dorsal cup. The union between the syzygial juijits is
nothing but an ordinaiy close suture, which may have striated or smooth surfaces.

I I

:i'

ii II I I mmi

tup: crixoidea camerata of north America.

the axillary ; while in species with two costals the first pinnule is given off
from the second distichal. In the HeterocrinidaB, in which the syzygies pre-
vail throughout the whole arm, they are formed in most of the species by
more than two plates. While Epactocrinus ymndia has but one hypozygal,
Ildcrocnniis ha? two or more, followed by the epizygal bearing the pinnule,
which in this group might be properly called an armlet. A similar arm
structure is found among the later Calceocrinid*, and also in the Belemno-
crinidoe. In Epadomims f/randis the syzygies are especially well marked, the
epizygal joints being wedged-shaped, the hypozygal quadrangular, and
arranged parallel to the distal faces of the preceding epizygal.

In some groups of the Fistulata it is exceedingly difficult to discriminate
between pinnules and armlets. As a rule, pinnules are more delicate, and
are given off, except in cases of syzygy, from successive joints ; while most
of the armlets are arranged at more or less irregular intervals along the sides
of the ordinary arms, and are usually branching. We find armlets among
the Heterocrinidoe, Belemnocrinidoe, in Bari/cnnus, Botri/ocnnvs, and the later
Calceocrinidoo. The Cyathocrinidae have long filiform arms, which frequently
dichotomize, but have neither armlets nor pinnules. The Anomalocrinida)
have branching arms with pinnules. The latter are given off in rows from
every joint at one side of the arm only — not alternately from opposite
sides — fron. one axillary to another, reversing their position in the succes-
sive divisions. The HybocrinidaB, svhich represent one of the most primi-
tive forms of the Fistulata, possess but one arm to the ray, and have neluier
pinnule.'! nor armlets. The Catillocrinidcc have numerous simple, pinnuleless
arms, given off directly from the radials, without the interposition of
axillaries.

In the Camerata the lower brachials take part in the calyx. That these
plates were free in the early larva, and Avere gradually incorporated, is
clearly indicated by the ontogeny of recent Crinoids, as well as the phy-
logeny of fossil ones. In the early Pentacrinoid larva of Antedon the
arms are free from the radials up, and the costals and distichals are sub-
sequently drawn into the calyx by the gradually increasing perisome. This
was evidently the case in the Camerata also. But while in the former the
perisome consists of soft tissues encrusted with limestone particles, the peri-
some of the latter is formed of well-defined plates. Our knowledge of the
ontogeny of Camerate Crinoids is of course limited; all we know is that
smaller specimens have a less number of interbrachial plates, that the number

\ \

MORPHOLOGICAL PART.

increases with the size of the specimens, and that with the increase of the
latter additional brachials are incorporated into the calyx. We have found
a number of young specimens in which the arms are free from the first
axillary, but, as yet, no Acllnocrinus or likodomnus in which there is not at
least one interbrachial.

We find among the Camerata a large number of transition forms in
■which the costals do not form a part of the dorsal cup, and the first inter
radials, to a large extent, are interambulacral in position. Such is the case in
the Platycrinidaj, HexacrinidsR, Acrocrinidoe, and Crotalocrinidoe. In Phiy-
crimis the distal ends of the radials are provided with a horse-shoe-shaped
excavation, which closely resembles the facets of the Inadunate Cyatho-
crinidce. This facet, which in some species extends down to two-thirds the
length of the plate, rarely takes up more than half its width. It is occupied
by the costals, or, when these are very small, in par<^^ also by the first dis-
tichals. The costals are narrow, and resemble in form and general appear-
ance the free brachials of Inadunate Crinoids. They are, however, not free
in the sense of these, but the proximal ends of one or both plates are sutur-
ally connected with the plates of the tegmen, so as to be immovable, .and
only their upper ends are free from the calyx.

It has been generally supposed that there was in Platycrimis and Dicho-
crimis an articulation or loose union between the radials and costals. This
seemed to be confirmed by the presence of the facet, and by the fact that in
some species this is provided with a sort of imperforate transverse ridge, or
angularity. We have no doubt that these costals were movable at some
period of life, probably in the larva before the perisome made its appearance,
and the r>rals still rested upon the beveled edges at the outer ends of the
radials. But it is equally certain that the plates were immovable in the
adult, owing to the rigidity of the interradial and covering pieces, with which
they are suturally connected. The systematic position of the Platycrinidce is
intermediate between the Inadunata and the typical Camerata. They repre-
sent phylogenetically an early stage of Actinoerinus, Batocrinus, and their
congeners; but are nevertheless true Camerate Crinoids, for their lower
brachials are fixed, retaining, however, permanently to a large degree the
characteristics of free arm plates. In Ciilkocrmts and Plerotocrims, the one
a Platycrinoid, the other a Hexacrinoid, the Camerate type is somewhat
more advanced, as their costals practically enter the dorsal cup ; and there
are a few species of Plati/crims in the same condition (Plate LXXI., Fig. 16).

1 .'

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

So there ia nn almost uninterrupted series of forms from the Inadunata to
the most completely developed Camerata.

It has been stated that in Dichocriims the various orders of brachials, to
the last bifurcation, consist of two plates each, and that the plates of each
order form a syzygy, the epizygal bearing an arm instead of a pinnule. A
similar structure is found in most species of Plali/crinus from the costals up,
and although the union between these plates may have been less close than
in Dichocrinus, they evidentlj' form a syzygy, except in cases in which the
first plate of the order is pinnule-bcving, as in P. Uunisvillcc and P. Surce.
It is very significant that in both these species, and a few others, the first
pinnule is given ofTfrji^ the first distichal, and the second on the same side
from the first palmar, thus showing that the arm partakes of the alter-
nation of the pinnules ; and this suggests the question whether all arm-
branches are not enlarged pinnules. In Eucladocriims, which is actually a
highly differentiated Plaf^/criiius, the branches are given off alternately from
every second joint up to the end of the rays, exactly like the pinnules in
cases of syzygy ; but while in PMi/crinus the axillaries are in their normal
condition, — the superior faces equally divided, — in Eucludocrinus they are of
irregular form. They resemble enlarged pinnule-bearing plates, of which
the side supporting the next order of brachials is much wider than that
giving off the arm (Plate LXXIV).

There can be but little doubt that in Euchdocrims the lateral arms in the
young Crinoid were pinnules ; and there is abundant proof that this was
also the case with the arms of other groups, as is well shown by Glyptocrinui
Dyeri, In most species of Gbjptocrinus, for example, G. dceadadi/lus* the
second bifurcation takes place from the second distichal. In G. Dycri, how-
ever, this plate gives off from one side in place of an arm a large pinnule,
more than twice the size of an ordinary one ; and a second pinnule, but
little smaller, starts off from the fourth distichal on the opposite side. Both
pinnule-bearing joints have nearly the shape of true axillaries, and what is
most remarkable, the arm bends outward, forming an angle, as if a true bifur-
cation took place. (Pla^ie XX., Fig. 1 a, b, c). The four or five proximal
pinnules of this species are incorporated into the calyx, and it is quite evi-
dent that the growth of the armlets — or pinnules, whichever they are —
was arrested by the rapid upward growth of the perisome. All succeeding
pinnules are small, and given off alternately from successive joints.

* This species has twenty arms, and not ten as indicated by tlie name.

S I

MORPTTOLOGICAL PART.

The structure of this species is a very strong indication that the arm
branches are modified pinnules ; and this suggests that non-pinnule-bcuring
brachials, whether fixed or free, may form a syzygy whether the succeeding
axillary supports an arm or a pinnule. Carpenter pointed out* that among
recent Crinoids, with but few exceptions, " the first two joints beyond every
axillary of the dividing rays are united to one another in the samu man-
ner, either by syzygy or bifascial articulation." This rule seems to hold
good also for most of the Pala;ozoic Crinoids, with the exception that we
find among them only syzygies, and no articulation.

The Actinocrinidae, as we have stated, represent an advanced stage of
the Camerate type. Not only their costals, but also their distichals, and
generally several more orders of brachials, participate in the formation of
the calyx, and all the branches are given off alternately from opposite
sides of the main trunks. In the genus Aciinocnmis, f only every second
or third brachial of each order in the calyx supports an arm (Plate LX.,
Fig. 1«) ; but in Caeioen'ntts, Phijsdocrimis, Tclciocrimis, and Slrotocyiims, an
arm originates from each successive plate (Plate LXV., Figs. !« and \c), and
the arms alternate like the pinnules. In Ac/inocriiws occasionally, and in Am-
phoracrimis generally, branches are also given off at irregular intervals from
t'le free arms; but these evidently made their appearance after the arms
had become biserial. In Steganocrimis the branching is continued to the top
of the rays, as in Eudadocrinus (Plate LXL, Figs. 1« and \d), and each order
of brachials consists of one, two or three plates, Avhich are formed into tubular
appendages of the calyx, giving oflf biserial, pinnule-bearing arms. Accord-
ing to our interpretation, we have in Adinocnnus and Sleganocrimts a series
of syzygies, in the former extending to the top of the calyx, in the latter to
the top of the rays ; as opposed to Cadocrimis, Strotocrimis, etc., in which
each order of brachials consists of a single plate, which is axillary.

The pinnules of the Actinocrinidoa differ from those of other families in
being provided with prominent hooks, directed obliquely upward and out-
ward. These hooks are arranged in rows parallel to the sides of the arms,
and those of one pinnule overlap the corresponding ones of adjoining pin-
nules (Plate LVIII., Figs. 1 and la, b, c), so as to give to the mass of pinnules
the appearance of a highly complicated network.

• Clmll. Rep. I., p. 49.

t We subdiviilc the genus Actinosrinus, as heretofore recognized, into Actinocriiius proper, and Carfo-
criniis ; referring to the former only tlic lobcd speeies with two or more brachials to cnch order; and to tlic
latter those in whicli the free arms are arranged equidistant around the calyx, and each order of brachials
above the costals consists of but one plate.

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

I I f

; ;

In the Biitocrinida), we find an arm structure such as occurs in no other
group. While in all other Caincrata the anibulacral t ironings of the calyx
give origin to but a single arm, those of the Batocrinitos frequently bear two,
either from every opening or from any less number of them, and this, which
is very remarkable, even in the same species. Thus the specimens may have
eighteen arm openings and but eighteen arms, or any number from eighteen
to thirty-six. This mode of multiplying the number of arms is found only
among the later forms, and it is evident from the structure that the second
arm, where it occurs, was introduced in the nearly mature individual after the
arms became biserial, and the lower orders of brachials had been incorporated
into the calyx. The bifurcation takes place in the same manner as in free
biserial arms, there being no true axillary, and the plate taking its place
is no larger than the succeeding arm pieces.

In the Batocrinidae, all branching in the calyx is by means of dichotomy,
and the number of arm openings in the three anterior rays rarely exceeds
four; but there may be only two or three, and in the posterior rays, the
arms next to the anal interradius may bifurcate once or twice again, so that
two of the rays have five or six arm openings. In some genera the number
of arm openings varies considerably among the rays, the anterior, or occa-
sionally the antero-lateral ones, being generally the least developed. This is
not the case in the Actinocrinidao, in which normally, with one or two excep-
tions, the number of arms is equally divided among the rays. In the Peri-
echocrinites, which we made a subdivision of the Batocrinidae, the free arms
almost always branch in their biserial stage ; while they remain simple in
the Batocrinites.

In Mclocrinus a very peculiar arm structure occurs, somewhat similar to
that of Stcganocrimis and Eucludocrimts ; but while in the latter the two divi-
sions of the ray form independent appendages, all the way from the calyx
up, those of Mehcrinus, either for some distance or to the full length ot the
rays, are laterally connected, and form together but one appendage, from
which the arms are given ofiT at intervals from opposite plates in the ray,
and from one side only of each half.

In most of the RhodocrinidfB and Thysanocrinidae, the arms branch in
their free stage, whether uniserial or biserial. The arms of Ripidocrinus are
given off at both sides of the main rays, as in Stet/anocnnKS sculptus. Those of
Gilbedsocnnus are very delicate, and frequently pendent. The latter is the
case also in some species of Acrocriniis, and the Swedish genus Banandeo'

MORPHOLOGICAL PART.

cn'ntis, in which they completely envelop the calyx, exposing their ventral
Burfacea.

The mobility of the arms in the Camerata must have been limited, as we
nowhere find at the apposed faces of the various brachials any trace of a
muscular attachment. Those brachials which take part in the calyx arc,
like the other calyx plates, united with one another and with adjoining
plates by close suture, the apposed surfaces being flat and generally smooth,
rarely striated ; and the plates are immovable. The first indication of any
kind of articular facet occurs on the highest plate of the calyx ; i. e., that
bearing the free arms. This plate is usually more or less concave, often
striated, sometimes having a sort of ball-and-socket arrangement, or being
provided with an obscure transverse ridge ; and in a few cases it is perfo-
rated. The faces of the higher arm plates are smooth or striated, and but
little concave ; yet there must have been a considerable amount of mobility
even among them, for the tips of the arms are frequently curved inward, and
in some cases the arms are decidedly spreading.

The mode of union between the brachials of the earlier Fistulata was
similar to that of the Platycrinidoc. The Dendrocrinida) and Cyathocrinido)
have more or less well developed facets upon the radials, and the arm
plates are united among themselves and with the radials by ligaments
only, so as to admit but little motion. In the later Fistulata, however,
notably the Poteriocrinida) * and Encrinidas, there is a muscular articula-
tion between the axillaries and the joint succeeding them, as in recent
Crinoids.

The Larviformia, so far as they are known, have a well differentiated
muscular articulation, with transverse ridge and fossae between the radials
and costals, but not between the succeeding brachials. Ctiprcssocriims, Alhffc-
crinus, and Si/mbctthocrinus have large muscle plates connected with the radi-
als ; while the other brachials are so closely united one to another that it
appears as if the whole arm had mo '' rigidly upon the radials.

In the Ichthyocrinidao all the brad lals, whether fixed or free, are mov-
able. The calyx was pliable from the radials up, as is shown by the apposed
faces of the plates, which are deeply hollowed out ; not only those of the
brachials, but the interbrachial plates as well. Tlie cavities, which evi-
dently lodged large bundles of ligament, contain small elevations with stri-

* It is unfortunate that the genns Poteriocrinus has been made the type of tliis family. It is tlie only
genus of tlie Poterioevinidte in wliich the facet supporting the arms is horsc-shoe-.'liaped, and the costals do
not occupy the full width of the radials, which is so characteristic of the family.

* \

THE CRIXOIDKA CAMERATA OF NORTH AMERICA.

ated faces. Those of the fixed brnchiiilH form irregular ridges, which proceed
from both sides of tlie phitcs toward the middle without meeting. The
apposed faces of tlie free arm plates have been rarely observed, but ho far as
known they are more or less concave, and we have found on some of them
indications of transverse ridges. The lines of imion between the brachials
generally have a waving outline, and many of the species have a sharp pro-
cess projecting from the distal end of tiie plates, which fits into a shallow
depression upon the outer face of the plate below. In some species, especi-
ally the larger ones, this projection forms a separate jtlate. The arms of all
IchthyocriniduQ are uniserial, the joints quadrangular, and they are destitute
of pinnules.

II. THE PLATE-S OP THE ACTINAL SYSTEM.
A. T/w Orals.

The orals arc not always represented in the adult Crinoid. When
present, thoy surround the mouth or cover it; and they may occupy the
whole face of the ventral disk, or only its median portions. In the former
case they rest upon the edges of the radials ; in the latter against the peri-
some. In Crinoids with a regular pentamerous symmetry tbey consist of five
pieces, interradially disposed, and occupy the centre of the disk. When the
symmetry is irregular, they are pushed more or less toward the anterior side.
The former condition prevails among the recent Crinoids, and in the Larvi-
formia ; the latter is the general rule among Palaeozoic forms. When asym-
metrical, the posterior oral is pushed in between the four others, and is
generally larger (Plate III., Figs. 11, 17, 18, 20. 21, 22, and 23).

The orals are among the earliest plates developed in the larva. They
make their appearance simultaneously with the basals, upon which they rest
until the radials are introduced, when they occupy the beveled upper edges
of the latter plates. In the larva of recent Crinoids they form a pyramid,
composed of five nearly equal pieces, which at first are laterally united and
closed at the top ; but they soon open out, and expose the tentacular vesti-
bule. At a more advanced stage the orals are carried inward by perisome,
until finally in most of the species they become resorbed, and are replaced
by upward perisomic growth. In only a comparatively few recent fonns do
they persist through life, and in these cases they occupy the median portions
of the disk, and enclose the oral opening (Plate III., Figs. 9 and 10).

MOIU'HOLOdlCAL TAUT.

While thus among recent Criiioids the oriilM are readily recognized, their
identiliciitiun among I'aUuozoiu furnis has Ixh'Ii tiie Hiil)JL'ct of iniic.h oontro-
versy. Allnian*in 18GJ expreMscd tiie ojiinion tiiat the group of platew In
the centre of tlio vault of niuny PaUeocriiioids is a reprcsontative of the sim-
ple oral system of the young Cvinaliild ; but as those plates oftun consist of
more tlian five, it was not made clear to which particular ones his homology
applied. In most Palffiozoic Crinoids tliero is no oral opening, and the
arrangement of tho plates at the summit is irregular and ({uite varial)le.
This is tho case particularly among the Camerata, in which the median
portions of the disk are generally occupied by a largo, centrally located
plate, surrounded by eight or nine others, of which four are large and
similar in form and size. These four larger plates are directed toward
tho anterior side of tho disk, forming at their outer edges re-entering
angles, which are fdled by three rather large plates, radially disposed ;
while the four or five smaller plates of the proximal ring are directed
posteriorly, and are followed by numerous more or less irregular pieces,
directly or indirectly connected with tho anus (Plate III., Figs. 17, 18, 20,
21, 22, and 23). Occasionally tho larger plates are separated from one
another by small, supplementary pieces (Plate III., Fig. 23). This is the
case in some of the larger species, in which the small pieces were intro-
duced in the growing Crinoid. There are also species in which the larger
plates are not represented at all, and the whole ventral disk is composed
of minute pieces without definite arrangement, leaving only an opening
for the nnus (Plate III., Fig. 24).

The interpretation of these plates has proved tho more difficult because
in other groups, notably the Larviformia, the tegmen consists of but few
pieces, which have a dilTerent arrangement. In Alltiffccnnus and Myrtilo'
criniis (Plate III., Fig. 13), the whole ventral surface is covered by five large
interradial plates, resting upon the superior edges of tho radials, exactly as
the orals in the Pentacrinoid larva of Antedon. Ilaphmims (Plate III., Fig.
14) has five similar plates, which were at one time supposed to surround a
small central plate.f Si/mhathocnims (Plato III., Fig. 25) has a pyramid of
five large plates, four of them resting upon the edges of the muscle plates of
the radials, and partially surrounding a larger one, wedged in from the pos-

• Trans, noy. Soc. Edinb. Vol. XXIIT., pp. 245-251.

f Our supposed discovery of this plate in a specimen of Haplocriniia meipitiformis proved nftcrwnrds to
be a mistake, due to the peculiar fractures in tlie speeinicn. Carpenter, to whom wc submitted the specimen,

TIIK CHIXOIDKA CAMKRATA OF NORTH AMKRICA.

■l^

tcrior sitlo to a nearly central position. Tlio deHcription of the vcntriil plates
of th'm genim in tiiu Ik-vision, Part HI., p. 87, waH incorrect im to the small
pieces around the five Huintnit platcH, the appearance of which waH produced
by cracks and not sutures. SpecinienH of better prenervation show pomtively
that tiio ventral surface is occupied exclusively hy the five largo platcH.
Pindcriniis, as shown by a Hpecinicn of/*. j>iliilu in our poHHession from Dudley,
England, has a similar structure. Among the Caraerata five largo sunnuit
plates are known to exi.'*t onl_> in Coccocriims and Ciilicocri'tnis, the plates
of the former being equal (Plato III., Fig. 14), those of the latter slightly
unequal.

As tho largo central plate, when it occurs, occupies approximately the
same position as tho oral opening of recent Crinoids, it seemed plausible that
the orals, if present at all, should bo looked for in tho Cainerata among tho
plates of tho proximal ring ; but on examining tho structure, it was found
that only tho four larger plates could bo compared with tho five orals of
recent forms ; so the question arose, what had become of tho corresponding
fifth plate?

Wachsmuth, in 1877,* directed attention to the two plates of the same
ring adjoining tho four larger ones, and suggested that these two plates
taken together were probably equivalent to ono, being split into two by the
anu.s, and that tho six plates represented morphologically but five. The
plates were not, however, regarded by him as the orals ; ho thought the
whole ventral covering of tho earlier Crinoids was structurally distinct from
the disk of recent ones.

A similar view of the subject was taken by us in the following year.f
We assumed that the plates of the dorsal cup and those of the tegmen were
parallel structures ; that the central plate was represented in the dorsal cup
or abactinal side by the infrabasals, the six proximals by the basals, and that
other plates of the tegmen represented the radials and interradials. No
comparison was then made by us of these plates with the plates in the disk
of recent forms ; but this was done in 1881,:j: when we suggested that the six
proximals represented the orals.

Dr. P. H. Carpenter, like o'lrselvea, recognized in the Canierata a central
plate, for which he proposed the name " oro-central," and six proximals

veriQed our observiition, and held the plate to be homologous with the so^nllcd central plate of the Camerata,
(Cliall. Rep. on the Stalked Crinoids, p. 158).

• Amer. Joiirn. Sci. and Arts (series 3), Vol. XIX. pp. 186-187.

t Revision, Tart I., p. 28.

{ Revision, Part II, p. 17 (Proceed. Acad. Nat. Sci. Phila., p. 191).

MORPIlOLOCflCAL PART.

Rurrouiuling it. IIo rogiinltnl the forinur ns tlio uctiiinl reprcHontativc of tlio
(loD'o-centriil or turiiiiiiul plntu uf the ntum, mid tiiu latter tiio repreHcntntiveH
of the hnmiln. He took the pi'o.xiiiialH tu he tlie uiiiIh, heUeviiig with \\n that
the poMterior oral wa8 divided into two phiteit. He miid;* ''The proximal
dome phitcH rent directly agaitiHt the calyx interradiaU, that on the poHterior
Bide being reprenented by two Hniall plates with the anus between them;
while there is a more or less tidjercular ring of radial dome plates outsido
them. Theso proximal dome plates thus correspond exactly to the orals of
Symlialhocriniis and Jlajilocrinun, covering in the peristome, and resting against
the calyx plates, which in Vlafycrinus are the interradials, and not the upper
edges of the radials, as in the simpler forms. ... I cannot see what other
view can ho taken of the proximal dome plates which immediately surround
the oro-central, than to regard them as orals ; /. <•., as the actinal representa-
tives of the basals, like the corresponding plates in Si/mhathocriitus. If this
bo admitted, it follows that the proximal dome plates of all Plntycrinido),
Actinocrinldoa and Rhodocrinido) arc also homologous with the orals of Nco-
crinoids."t Carpenter's oral theory was based almost entirely upon the
hypothetical oro-central, — a plate before unknown in Echinoderm morpho-
logy, — and the six proximal plates, which he assumed to be orals, although
their morphological relations had never been established.

The same view of the question was also taKen by Etheridge and Car-
penter,t and afterwards by Neumayr;§ while Zittel || supposed the orals
to be unrepresented in all Platycrinido), Actinocrinidoo, Rhodocrinido), and
Calyptocrinidiu ; though admitting their presence in some of the other
groups.

The above theory was laid aside by us in 1885, when we ascertained that
the two smaller proximals, which we had supposed to represent the posterior
oral, occupy a radial position, and therefore could not be orals. The struc-
ture shows that these plates undoubtedly represent the two posterior radial
dome plates, pushed to a position amoii.cr the plates of the proximal ring by
the anus, the three anterior ones retaining their position within the re-
entering angles of the four larger proximals. This discovery was announced
by us in Part HI of the Revision, p. 47, and we designated the respective

• Clmll. Rep. Stalk. Crin., pp. 170 to 171.

t Dr. Carpenter's vie^s on this subject arc fully set forth in the Chall. Rep. Stalk. Crin., pp. 158
to 184.

I 1880. Catalogue of the Blastoidcn, pp. 06 to 76.
§ 1889. Die Stiimme des Thicrreiclies, p. 418.

II Haudb. der Folieont., I, p, 333.

tup: crinoidea camerata of north America.

plates by the letters " rx " in the accompanying diagrams.* There now re-
mained among the plates of the proximal ring but four which could possibly
bo taken for the orals ; and this led us to inquire whether the central plate
alone might not be a coalesced representative of the five orals of recent forms.

From internal casts we observed that this plate occupies the centre of
radiation, and that not only the ambulacra, but also the nerve cords, meet
beneath it. It was this structure principally which led us to the assumption
that the central plate represented the five orals collectively, and that the
four large proximals, and two smaller ones, were interradial " vault " plates,
corresponding with the first interradials of the abactinal side. This seemed
to us the more probable, as in the dorsal cup a division of the first interra-
dial into two halves by an anal plate is a frequent occurrence among Palaeo-
zoic Crinoids. It also seemed to explain why in Ilaploerimis and allied forms,
in which there is no anal plate, the central piece seemed to be surrounded
by five plates instead of six, supposing, as before stated, that IIa^)locrintis had
a small oral surrounded by five interradial plates, and Allagecrinus, Coccocnnns,
and Ciilicocri'inis five interradials, but no orals. In this we differed from Gotte,
Carpenter, Zittel, and Neumayr; who all agreed that the Schciiclplaticn were
the orals.t

This was the state of the question in 1888, when we came into posses-
sion of a very large number of fine specimens of Ilaplocnmis mcspillformis
in various stages of preservation, and found to our astonishment that
such a thing as a "central" plate does not exist in the genus. We now
sow that the ventral disk consists of but five large plates; that we had
mistaken a mere fracture for a suture ; and that the part which we sup-
posed to be a separate piece was a tongue-like prolongation of the posterior
plate, projecting in between the other four plates, and sometimes surmounted
by a small node (Plate III., Fig. 12J). This discovery left no room for doubt
that the large ventral plates of Ilaplocrinus, and of the Laviformia generally,
actually represent the five plates composing the unopened oral pyramid of
the Pentacrinoid larva before it moved away from the radials, as had been
contended by Carpenter and Goette.

So long as a central plate was recotrnized in Ilaplomntis, we saw good
reason to believe in the existence of a similar plate in other groups of the

• Revision, Part III. Plate VII. Figs. 2, 3, 4, 5, 6, 8, 9, 10, and Plate VIII. Pigs. 1 and 2.

t Our theory of the iclations of the summit plates, in conformity with these views, was discussed in the
Revision, Part III. pp. 44 to 59, and afterwards in greater detail in our paper on the Summit Plates, in the
Proceedings of the Academy of Natural Sciences, Philadelphia, March 39, 1SS7.

MORPHOLOGICAL PART.

Palaeocrinoidea ; but as soon as it appeared that there is no such plate, it
occurred to us that tlie plate, so apparently central in many Platycrinidoo
and ActinocrinidoD, might be a posterior oral, pushed inward to a central
position by dnal structures. This interpretation seemed to us one of the
greatest force, more likely than any other to answer the conditions of a valid
homology, and to remove the principal objections that had been brought
forward by Carpenter and ourselves respectively to other theories.

The idea of referring the plate to the orals was not altogether new. We
had already taken it into consideration before we knew the real structure of
Uaplocrimis, and alluded to it in the Revision, Part III, p. 5G, as follows : " A
far less objectionable interpretation of the central plate than that given by
Carpenter would be to regard it as a posterior oral. In this case the orals
would be represented by five plates, and not by six ; the anus would be
placed outside the oral ring, and the radial dome plates would occupy the
same position towards the orals as the calyx radials toward the basals. But
it would place the mouth underneath the posterior oral, and it offers no
explanation of the central piece in Ilajilocriints." The last of these diffi-
culties which then seemed so serious was met by the elimination of the
mythical plate in Uaplocrimis; and the first was destined to be perfectly
cleared up by the recovery of a new fragment from the scattered pages by
which Nature unfolds her palajontological story to us.

While writing up the observations which we had made on Ilaplomims, we
made another still more unexpected and striking discovery, which in our
opinion settled the oral question in conformity with the last mentioned sug-
gestion beyond all controversy. Up to that time the ventral structure of
the IchthjfocrinidoD had been almost totally unknown. By extraordinary
good luck ve obtained a specimen of the genus Taxocriims with the ventral
disk in alnost perfect preservation, and after carefully cleaning the speci-
men, we found that it had an external month, mirroumled hy five parted oral plates,
nith the ambulacra convergwf/ to it, and passing in between the orals. (Plate III.,
Fig. 11.)*

The middle of the disk is occupied by five rounded or very obtusely
polygon.al plates, interradially disposed, rather oval in outline. The two
antero-lateral plates are tolerably good-sized, and the postero-lateral ones
slightly smaller. The posterior plate is nearly three times as large as any

• A full nccoiiut of this unique specimen was given by us in a paper, " Discovery of tlic Ventral Struc-
ture of Taxocrinua and Hnploerinua, and Consequeul ModiQcations in the Classification of the Crinoideo."
Proceed. Acad. Nat. Sci. Phila., Nov. 27, 1888.

Ill

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

of the others, and almost twice as long as wide, extending well in between
the two postero-lateral plates.

The positions of these plates are relatively identical with those of the five
plates at the summit in certain forms of Plati/crinus, such as are illustrated on
Plate III., Figs. 16 and 17, except that the plates of Tuxocnnus do not meet
in the centre, but leave a slightly excentric, obtusely pentagonal oral open-
ing, transversely elongated, its longest side next to the posterior i^late. Into
this opening, which is deep, the ambulacra converge, and turn downwards at
the five corners.

That the five plates of this .specimen, although somewhat unequal in size,
represent morphologically the five orals of the recent genera Rhkocrimis,
H>/ocrinus, and IIolopus, nobody will deny after seeing the specimen. And a
comparison of these plates with the so-called central plate and four large
proximals in Plnti/cnmis, Adinocrimis, etc., leaves no room for doubt that these
are likewise true orals. The arrangement of the plates in the different
groups is practically the same ; the only difference is that in some they are
less symmetrically disposed than in others. In Taxocrinus, the anus is well
removed from the oral centre, which accounts for the fact that the arrange-
ment of its orals is rather more symmetrical than in most of the Camerata?
in which the anus is more or less subcentral, and surrounded by heavy, rigid
plates. That the amount of asymmetry depends upon the condition of the
anus is cleai'ly shown by the figures on Plate III. Wiien the anus is excen-
tric, and its plates are small, the arrangement of the oruls is comparatively
symmetrical ; but when it is subcentral, and especially when it is extended
into a lai'ge tube, the orals are pushed over to the anterior side. In Haph-
erimts, in which the anus penetrates the orals, and in Coccocrimts, in Avhich it
occupies the arm regions, the oral pyramid is naturally about symmetrical. It
is now easy enough to understand how a set of five plates, synnnetrically dis-
posed over the mouth, could be so altered by the introduction of anal plates
as to bring the mouth and centre of radiation beneath the posterior plate.
By the encroachment of the anal plates the posterior oral was pushed to a cen-
tral position, and thereby the mouth came to be placed beneath that plate.

The above explanation of the orals in the different groups met the
prompt approval of Carpenter, and this ended a long controversy Avhich
had been going on between us for over six years. The orals were found
at last to consist of four of the proximals which he had claimed, with the
addition of the so-called central plate which we had contended for.

I II

MORPHOLOGICAL PART.

It remains to consider the views of Neumayr. As already stated, he
agreed with Carpenter that the ScheitclpMtcn oi Haplocn'nus, and the six proxi-
mals of the Camerata, represent the orals. He also believed in the prencnce
of a central plate within the oral ring in both groups. But he differed
both from Carpenter and us as to the plates representing the orals in the
CyathocrinidoB.

The structure of the ventral disk of Ci/athocrims exhibits considerable
variability, and a comparison of the various plates among the different
species is by no means an easy matter. As a rule, there are four large
interradial plates located ventrally, resting upon the inflected upper edges
or limbs of the radials, and at the posterior side two narrow longitudinal
strips, which enclose a large, perforated madreporic plate lying in front of
the ventral sac, and whose lower (outer) edge is in contact with the sac.
The plates are laterally united by suture, and leave five well defined grooves
which are occupied by the ambulacra. Within these plates, towards the oral
centre and covering it, there is a variable number of other large plates, often
of the most irregular arrangement, varying in form even in the same species,
and in some cases exhibiting the asymmetry of the orals in the Camerata.
The difficulty of ascertaining the morphological relations of these plates in
the different forms is increased by the fact vhat the surface of the outer
plates — those nearest the radials — is covered by numerous minute peri-
somic pieces, interposed between the ambulacra. The ambulacral plates
consist of side plates and covering pieces.

Neumayr * speaks of only one ring of plates, resting against the radials
and surrounding the mouth, and he assumes that the disk of Ci/athomims
is morphologically in the condition of Haplocrinus, except that the ambu-
lacra in the latter are subtegminal, but tegminal in the other. We have
illustrated on Plate III the ventral structure of Ci/aihocrinns by a series
of specimens of different geological ages, and in various stages of preser-
vation, which show that the disk is composed of two sets of plates, the
one within the other, and that in cases where but one ring is visible the
plates of the second are covered by other structures, or have been resorbed,
or are not preserved in the specimen. It is evident that Neumayr has in
some instances confounded the plates of one ring with those of the other.

Examining first the two specimens of C. Gilesi{¥ig9. 1 a,h), there appears
to be but one ring of plates, and these rest against the radials. In Fig. 1 a

;; * '

* Die Stamme des Thierreicliea, pp, 419-452.

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

\ y

those plates are completely exposed, in Fig. 1 b partly covered by marginal
pieces ; but in both of them there is at the middle of the disk a moderately
large vacant space, which in perfect specimens is tightly closed by additional
plates. C. brevisacculus, Fig. 2, has two rings of plates: an outer one, com-
posed of five subtrigonal pieces, of which the posterior one is largest and per-
forated, and an inner one, composed of five pairs of plates nearly as largo as
the former but of variable size and form, which meet in the centre, so as to
close the mouth and peristome. The ambulacra are exposed all along the
plates of the outer ring, but are covered by the plates of the inner. In
C. noilosus. Fig. 3, and C. muUihrachiatus, Fig. 4, the four large interradial plates
above the radials, which in the preceding figures are wholly or partly exposed,
are completely hidden from view by small marginal pieces. The middle of
the disk is covered by a nuniber of rather large pieces, even more irregular
in their arrangement than those of C. brevisacculus. The ventral disk of Euspi-
rocrinus xpintUs, Fig. 5, has at four sides a very large, convex interradial plate,
and at the posterior side an unusually large ventral sac, with a small madre-
porite at its base ; the ambulacra are tegminal ; and the median portions of
the disk are closed by moderately small, elongate plates, arranged in rows
with the side pieces, which meet in the centre. Very different is the disk of
Ci/alhicrinus alutaceus, Fig. 6, which has at the summit five large plates, in form
and arrangement resembling the orals of Plafi/crinus. The posterior one is
largest, subcentral in position, and pushed in between the other four. There
are no grooves along the lateral margins of tl plates, the ambulacra being
subtegminal ; but the re-entering angles at inc lower end enclose five well
proportioned radial dome plates.

Comparing the summit structure of C. ahfaceus with that of the Camerata,
it is quite evident that the five large plates of Fig. 6 represent the so-called
central plate and the four larger proximals. This was also the opinion of
Noumayr ; but while we take all five plates to be orals, he clung to the idea
of a central plate, and recognized six orals, assuming that two of the radial
dome plates represented the posterior oral. We do not see how those plates,
which occupy the median portions of the disk and cover the mouth and ends
of the ambulacra, can be the morphological representatives of the plates
which in Figs. 1, 2, and 5 rest upon the radials. Neumayr took the two
structures to be equivalent, while we believe that the plates of the former
represent the orals, and that the latter are accessary pieces of a similar
origin to the interradial plates of the Platycrinidce.

MORPHOLOGICAL PART.

According to Neumayr, the disk of Cijalhocrinm is composed of five large
plates, which, like the SchcitdpMten of JIuplocrinus, abut against the radials.
The plates, he thinks, are in sutural contact laterally, but leave at the sum-
mit a large space for t''e mouth. The ambulacra are exposed upon the sur-
face, resting within the deep grooves, formed along the lateral margins of the
plates. They extend from the mouth to the bases of the arms, and are cov-
ered by small plates, which project inward over the peristome, and close the
mouth externally. The small marginal plates, which, as he states, in some
species extend over the whole disk, he takes to be " eine secundiire Wuche-
rung " of the side and covering pieces.

His description does not agree with our idea of Cijdhocrimis ; it comes
closer to the structure of Easpirocrimts spiralis, from which it was probably
made. The latter really seems to have but one set of large plates upon
the disk, which touch the radials, and enclose at the summit moderately
small plates, which may be ambulacral pieces ; but the former are not ovals.
Cijathocnmts Gilcsi, as represented in our figures, has also but one ring; but
there is a large vacant space at the middle, which was evidently closed in
more perfect specimens by an inuer ring of plates, as in the other species.
C. brcvisnccuhts has an outer ring of plates and an inner one, and the ambu-
lacra, which are exposed upon the former, are hidden by the latter. In C.
mnlllbrachiatus the outer ring is covered by marginal plates, the inner rep-
resented by a few irregular, large pieces, scattered upon the surface, and
intermingled with ambulacral pieces. This specimen was illustrated by
Neumayr on page 473, from our figure in Part III of the Revision, and he
must have taken the irregular inner pieces for the orals, for only in this
way can we understand the explanatory remarks accompanying the figure.
He says : " Wachsmuth and Springer figure a most remarkable example of
Ci/athocrinns muUibrachiatus, in which, as they .show, the orals (summit plates)
are in process of resorption, and in part replaced by small plates." In
C. alulaccns also, he took the inner plates, which in this species are un-
usually large and regular, for the orals, and for the homologues of the
outer plates of C. malvacetts* 0. Gilcsi, and C. hrevisaeculm.

" Neumayr gave (Stamme des Tliierreiclics, p. 450), after Meek and Wortlicn, two figures of tlie ven-
tral surface of this species: Fig. 2, representing the " Kelclideckc " ; Fig. 3, "Dicselbc, uacli Entfernung
dcr Dcckiiliittclicn." The former has five largo intcrradial plates, with a vacant space in the centre, mucli
larger than tliat of C. Gilesi, and the ambulacral grooves are exposed. In the latter tlie centre is closed by
seven plates, almost as large, and as regular in their arrangement (a central ))late surrounded by six proxi.
mals), as in C. alulnceu-i. That he took these plates, contrary to those of C alufmrus, for covering pieces,
extensions from the ambulacra, and not for orals and central plate, is clearly indicated by the explanation of

the figures.

ili

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

I fir

nil

( i'',

III

Neumayr's interpretation of the plates meets with serious diiricuitics.
There are in C^a/hocriitus uniloubteilly two sets of plates ; the one occupy-
ing the cent»'e of the disk, and covering completely mouth and peristome,
without grooves, and with the ambulacra subtegminal; the other occupying
the outer margins of the disk, grooved, the ambulacra tcgminal, and covered
over by perisome which extends inward and closes the mouth. He under-
took to explain these difliculties by palasontological development, but over-
looked the fact that in the ontogeny of recent Crinoids the perisome is
introduced above the radials, and between the orals, and that the latter are
carried relatively inward. The same mode of development we find in the
phylogony of fossil forms; the orals, with the introduction of interradial
plates, are moved to the centre of the disk, and either cover the mouth
or mmcd'uttclij siirrouiul it. That is the caso in the Camerata and the Articu-
late Ichthyocrinida?, and there is no reason to doubt that it is the same way
in the Cyathocrinidiv. In the Larviformia, however, in M'hich there is no
perisome, the orals rest against the radiiils, but also cover the mouth, as
they do in the Pentacrinoid larva.

We believe with Neumayr that the differentiations among the species
which we have noticed in the disk of Ci/athocrimis are modifications due to
palaiontological development. It seems to us that the orals throughout this
genus are more or less in a state of resorption, more advanced in one species
than in another, and even varying in degree in the same species. From this
we conclude that the Silurian C. aluUiccus, in which the orals are almost or
wholly intact, represents the more primitive form of the genus, and C. iiialva-
cetis, etc., a later stage ; and that Empirncrimts, in which the orals are appar-
ently completely removed, and the ambulacra thereby brought into view
upon the disk, represents a more advanced stage than either species of
Cyuthocrmus.

For proof that a resorption took place in the same species, we refer to the
specimen of C alutacnis, Fig. 7, which differs essentially from Fig. G. It is
also proved by numerous specimens in our collection,* which show distinctly
that the orals are proportionally larger, and more regular in their arrange-
ment in young specimens than in the adult. In one of the specimens, not
larger than a good-sized pea, they occupy fully two-thirds of the disk, being

• Wo have from sixty to seventy specimens in most excellent preservation, represeiitinR five species, in
which we exposed tlie disk by removing tlie arms. Jlost of them came from Indian ereck, Ind. (Keokuk
group), though some arc from Burlington, and a few from Crawfordsville.

MORPHOLOGICAL PAllT.

thus considerably larger than the plates occupying its outer niaryins, which
arc also exposed in that specimen.

We thus find persistent among Palaeozoic Crinoids all the phases through
which the orals pass in their individual growth in recent forms, from the
early Pentacrinoid larva oi Anh'duii to the adult IIi/omnuH (Plate III, Fig. 10)
in which they are very large, and Calumocriintu * in which they lire extremely
small ; and we find the plates in process of resorption and entirely removeil
from the system.

We further find that the orals in all Crinoids, recent and fossil, v.hen
represented, occupy the centre of the disk, immediately surrounding the
mouth or covering it, and that the orals of the earlier forms differ from tliose
of the recent only in their asymmetrical arrangement, caused by the greater
rigidity and more extensive development of the anal structures.

B. Mouth and Amhdacra.

The presence of a single aperture in the disk of Palaeozoic Crinoids
induced the earlier writers to suppose that this opening, although interradi-
ally disposed, served both as mouth and vent. Later ob.servations, and
a better knowledge of the general structure of recent Crinoids, their mode
of feeding and the nature of their food, have shown conclusively that this
opening is not the mouth, but the anus, and that the mouth in most PaUvo-
zoic forms was subtegminal.

The mouth of all Crinoids is directed upwards, being placed in the centre
of radiation, but does not in all of them occupy the centre of figure. It is
very frequently subcentral, and may be altogether excentric. The latter is
the case in the asymmetrical genus Acllnomcim, and to some extent in all
Fistulata, in which the posterior side of the disk is extended into a large
tubular or sac-like prolongation. It is subcentral in most of the Camerata,
and central in all known recent forms, Adinometra excepted.

The ambulacra occupy the grooves along the ventral side of the arms,
and extend from the tips of the pinnules to the mouth. Their proximal
ends are either exposed upon the disk, or covered wholly or in part by
plates of the tegmen. Entering the mouth there are five main trunks,
which ramify so as to give a branch to every arm and pinnule. The upper
face of the ambulacra is occupied by the food grooves, which are roofed over

• A. Agassiz, ^Icmoirs Mus. Comp. Zool., Vol. XVII, Plate 0, Figs. 1 aud 2.

100

THE CBIXOIDKA CAMKRATA OF NORTH AMERICA.

Ifc

■1;

\)y the covering plates, and fiecinently bonleruil by small side pieces ; the
I'ormer arnuiguil alternately with each other and with the side pieces. In
the living uniinal the food grooves are lined by cilia, whith are kept in a
continual vibratory motion ,so as to produce ciu'rents of water, by nieiiiis
of which any particles of food that hapjjen to fall upon the grooves are
transmitted toward the mouth. Beneath the food groove lies a nervous
band, and beneath that a blood ve.s.sel, which in turn is followed by the
genital canal, and this by the subtentaculur canal ; the genital canal, which
is quite small, occupying only the median portions. The subtentacular
canal, also known as the ambulacral canal proper, from which branches are
given off to the tentacles, communicates with the annular ves.sel situated in
the lip around the mouth. Beneath the ambulacra is the nxial canal.*
which occupies the bottom of the arm grooves, frequently piercing the body
of the plates. This canal is connected with the chambered organ at the
lower part of the dor.sal cup, and contains the axial cords, which, as now
generally admitted, control the movements of the arms and pinnules ; while
the nervous apparatus beneath the food grooves bus no connection with
the muscles, and no inlluence upon the movementh of the skeleton.

The ambvdacra of fossil Crinoids are rarely observed, and their presence
is usually only indicated by the open grooves within the arm skeleton. In
some cases, however, the side and covering pieces of the di.sk, and occasionally
those upon the arms, are preserved.

In all recent Crinoids the covering pieces are movable from the tips of
the pinnules to where they enter the mouth, but they are rigid upon the disk
in Palivozoic species, with perhaps a few exceptions. In the Camerata, and
especially among the Platycrinidae, they are often heavier and larger than
the interandjulacral plates; while in other groups, and chiefly among Silurian
forms (Plate III. Fig. 11), they are quite small. The larger the plates, the
more irregular they arc in their arrangement, and the sm.aller the most
regular. It is also noteworthj' that the andjulacra may be tegminal or sub-
tegminal in the same genus. Those of the Platycrinidfe, as a rule, are tegmi-
nal, those of the Actinocrinidas generally subtegminal ; but also the opposite
is the ca.se in genera of both groups.

There is considerable variability in the extent to which the ambulacra
are exposed upon the surface. In the Camerata they never extend out to
the centre of the tegmen, their proximal ends being always hidden by the

• This canal is also known as the " Dorsal " canal, and as tlic " Cocliac " canal. •

ifi

5IORPIIOL00ICAL PART.

101

oraln, iind wlion these nre wantinj?, by some of the intorftmbiilncrul plates ;
or hy both, in which cnse only mnall portions of them are seen near the arm
bases. In the Fistulata, the disk ambulacra are either altogether tegminal.
or their ends are covered by the orals. In the Ichthyoerinida'. so far as
observed, and in recent Crinoids, they extend to the mouth, whether onds
are represented or not; but while in Tn.romuiis (Plate III. Fig. 11) they
are in the same plane with the orals, and are attached to them laterally,
in recent forms, in which the orals are opened out. they are deeply in-
serted between the interaml)ulacra! plates, so as to be almost obscured.

The disk ambulacra of the Camerata, if tegminal, form a component part
of the tegmen, being suturally connected with the intoramltulacral plates, and
with the orals. In the Cyathocrinida;, however, and probably in other Fis-
tulata, they rest upon largo interradial plates, and between the small margi-
nal pieces which cover the surface of the latter. In the lehthyocrinidie and
recent Crinoids, they are separated by minute interamltulacral pieces.

The ambulacra of the Catnerata rarely have any side pieces, these being
represented, so far as known, only in Mfi/ixfapriiiiis (Plate XL\'1I. Figs.
7 and 8 a, b), in Cdctocrinm (Plate LVIII. Fig.s. 7 n, 1>), and in L'/riocrhiiis
(Plate XI. Fig. 4 c). They are present, however, in most Fistulata. but
absent in the Larviformia.

That the covering pieces in the disk of C/jfif/iocrinns, as suggested by
several writers, were movable, so as to expo.se the food grooves, seems to
us improbable, although there is no serious objection to it from a morpholo-
gical point of view ; but the perfect preservation of the plates in so many of
our specimens seems rather to indicate that they were rigid. They may
have boen movable in groups in which the mouth is opened out, but where
it is closed they were probaljly rigid throughout the disk.

In some of the Camerata in which the primary arms are d veloped into
tubular appendages, and secondaiy arms are given off at the sides, as in
Eiichitlmriiws (Plate LXXIII. Fig. .3, Plate LXXIV. Fig. 4), and Stcyamcriiim
(Plate LXI. Fig. 1 c), the covering plates of the main arms are almost rigid
to the full length of the ray, and only those of the side arms and their pin-
nules were movable. But it must be remembered that these appendages are
practically extensions of the calyx.

Subtegminal ambulacra, so far as we know, occur only among the
Camerata and Larviformia. In the former there are frequentlj- along the
inner floor tbe tegmen deep grooves or ducts, which are formed either by

V.
» s

[■\

102

THK CHIXOIDEA CAMKUATA OF NOIITII AMKUICA.

a folding of the tost or a tliickeniiiy of thu plates, uml wliicli procecil from
tlic inukllo of the lloor to the iuin openings (IMtite V. Figs. 13, 1-1, 15, 1(5,
and 17). Within these grooves me lodged the unibulacni, whiuh me repre-
sented by n skeleton of riuliiiting tubes, following the inner surriice of the
di.sk (Plate V. Figs. 1 and 10; I'late IV. Fig. S). Tiie tubes are composed
of four rows of plates, two below and two ul)ove, both alternately arranged,
the former probably representing subanibulaeral pieces, the latter covering
plates. The skeleton has never been found completely preserved, but
enough is shown to indicate that the tubes do not extend out to the centre,
but meet in an annular ve8.sel surrounding the mouth. This at least seems
to have been the structure of Mucroirintis rcniati/idniis, in which an almost
circular vessel has been observed beneath the centre of the disk at some
distance from the inner lloor (Plate V. Fig. 8). No anibulacral tubes are
attached to it in the specimen, but it lia.s five openings in a radial direction,
which evidently communicated with the ambulacral vessels. The ring is
rather large, and is placed around the contracted upper part of the con-
voluted organ, which is also preserved in the specimen.

Tiie direction of the ambulacral tubes and tiieir branching is well
observed in natural casts, in which, after the calcareous parts arc removed,
the ducts of the tubes are represented by filiform elevations upon tlie
surface (Plate IV. Figs. 1, 2, 3, 4, 5), sometimes even showing impressions
of ambulacral pieces. It also appears from the.se casts that the ambulacra
in some cases rested directly against the tegmen, and in others lay at a dis-
tance from it, only touching the test at the arm bases. Tlic latter was
undoubtedly the case in the interesting specimen of riali/crinm (Plate IV.
Fig. G), in which the ambulacral plates are clearly marked near the margins
of the disk, while no traces are found of their inner portions. If the ambu-
lacra had touched the inner floor, the delicate markings of the disk plates
would not be in sight, but instead of them traces of the tubes would
appear upon the surface. This is corroborated by the cast of Dor/jcriiiKS
(Plate IV. Fig. 5), in which the ambulacra are visible to the outer edges of
the orals, but disappear underneath them. Also in the beautiful specimen
of Cacfocrinus proboscidulis (Plate V. Fig. 10), where the tubes are removed
from the floor,* and in Teleiocrinus (Plate IV. Fig. 1), and in Cacfocrinus glniis

* NiMimnvr, 'wlio knew this specimen from Meek and Wortlien's (Igurc, expressed the opinion tlint n
settling of tlie tubes probal)ly took pinee after tlic dcnlli of the nnimai. lie based tliis ojiinion upon tlie
structure of the casts, in which he supposed the ambulacra were always exposed at the surface, which, as we
have stated, is by no means the case.

MORPriOl.OniCAL PART.

103

(Plato IV. Fig. 8). Tliiit they wore attnclietl to the tcgmen in iniiny of these
CrinoidH, ntid prol)iiI)ly in the iniijority of them, in also Muygcuteil hy the
premMicc of the Mo-called radial dome plates.

The name "radial dome plate.s" was given by iih to a Met of large plafe,>t
in the tcgmon, radially dispo.sed, and oeciipying the regions lietween the
orals and tho arm bases. The plates arc generally larger than the surronnd-
ing ones, ami qnite froqnently nodose. They wore rcgar<led by ns, and also
by Dr. P. II. Carpenter, nntil iinite recently, as the aelinal representatives of
the radials, but later investigations prove the}' are highly dilTerentiated cov-
ering piocos. The plates are either followed by two series of regular cover-
ing piece.s, nnd pass out from between the angles of the orals, or they are to
a certain extent isolated, surrounded by other plates, and snccoeded by simi-
lar plates of higher rank. The former is the case in most of the Platycrinida>
and Ilexaerinida', the latter among the Actinocrinidio and Khodocrinida' with
subtegminal ambulacra. That the plates in the former case are simply cover-
ing pieces, is readily perceived by examining those species in which the
plates are but little disturbed. Taking Pl<if//irini(s and Dlchovrinus, wo find
in both genera certain species in which two series of small, almo it regularly
arranged, altcrnaiing pieces pass out from the orals to the arms. Such is the
case in Plid/jcriiim Ki/unnrtrlrm (Plato LXIX. Figs. 1 h, c), in Dii/iocrinns po///-
ihetylHS (Plate LXXVII. Fig. 1 h), and in 1). /,<c/irm>ms (Plate LXXVII.
Fig. 2 c). Similar plates under similar conditions also occur in the Silurian
Mtrmipiocrltms (Plate VIII. Fig. 15, and Plate LXXV. Figs. IGA and 18), and
among Silurian genera of other groups. There are no largo plates next to
the orals, and hence no radial dome plates, unless thoy are represented l)y
the small pro.ximal plates. From this struciuro to that of r/<ih/rn'iiiis dis-
coidem (Plate LXVI. Fig. 10 b), and P. ILdli (Plato LXXII. Fig. 7 "), there
is but a short step. The plates in question are comparatively larger, espe-
cially tho proximal ones, and arranged alternately, although not so regularly
as in tho former species. In PUdijcn'mis hitrli»f/foneusi,i, however (Plate LXIX.
Fig. 3 f), and P. YandcIU (Plate LXVIII. Fig. 3 c), there is generally a large
plate followed by smaller ones, and the alternate arrangement of the plates
actually commences at the arm bases. If wo had only tho latter species, we
might perhaps be justified in regarding those proximal plates as independent
structures ; but comparing them with those of other species in which the
arrangement is more regular, it becomes evident that they are all nothing

104

TIIF. C'HINOIDKA CAMKUATA Ol" NOUTII AMI.IUCA.

I)iit covoriiig i)ii;ci'>. wliieli gnulimlly in geological time cliungL'il tlicir
uluiractcr.

Tho " indiiil duiiiu pliitcM" uf tlio Actioiiucrinicliu iiiid nllicil fonuH mu
gotu'i'iilly liirgor tlmii niiy ol' the Miirroiiiuliiig ijliitos, often iiodoMe, ami hoiiio-
tiniuM extended into long HpincM. Tlioy uru nut ibllowcd innncdiiilely by
covering pieces, um already wtated, and are placed at some distance from
tlio orals, — occupying in the Minipler forni.s with bnt two arms to the ray
almost till' outer margins of the tegmen {AjarievvtlniiK), — directly owr the
point at which the bifurcation of the ambulacra takes place. When there are
I'onr arms to the ray, they are removed relatively further inward, and are
followed by two similar but smaller plates of higher raid^. But when there
are three arms to the ray, there is only one Huch plate, which is directed to
the side where the bifurcation is, the opposite hide of the plate being followed
by the regular covering pieces of the arms.

From this structure we may infer that the so-called radial dome plates
with sul)tegminal ambulacra are axillaries, and if they represent, as we have
rea-^on to believe, modified covering pieces, that they are the plates from
which the ainljulacra bifurcate. In this view it is quite suggestive that the
axillary plates of the ambulacra are frequently protuberant. In Enclmlieri-
iins iiiilldirachialus (Plate LXXIII. Fig. 1), they nre nil along the main arms
strongly nodose, and if tho ambulacra of this species had been covered by
other plates, the tips of the axillaries naturally would project above them
and be exposed upon tho disk. In this way the radial dome plates nniy have
originated, so that afterwards the upper portions developed to larger si/e, and
finally become independent plates. This explanation seems to us most prob-
able, and it was favorably received by Carpenter.

The Paheontological evidence indicates that in the earlier Caincrnta, ns in
the young specimen at some time, the ambulacra were exposed ujjon the
disk. In most of the Silurian forms they took part in the tegmen, and their
covering plates, as a rule, were more regular in their arrangement than in
those of later epochs. In the Carboniferous, with the exception of the
Platycrinida), Hexacrinidoo and Acrocrinidaj, the ambnlacra are almost
exclusively subtegminal, and the whole disk assumes that extravagant
form which led at one time to the belief that it represented an entirely
different structure.

Mom-llOlAMilCAl, I'AItT.

III. siim'm:mi;ntaiiy i'latks.

106

A. The Dii<(rit>iilioii <>/ lliv I'IkIik, uml llnlr Itt'tnltimn in the Di//'iirH/ Oronpi.

Tho jstippleiiuridil iilati'M coiiipiiNo all liiiu'stoin' piiitirlL'M Itctwccii tlio
ba^nls and (inil-'' and iiiti'ivcnin^ l)ot\vei'n tlio lays and tlicii' HulidiviNiotiH,
They iiro <HviduJ into interradial, intoiiixiliary, and anal pliitcx. The ii)tRr>
radial plutt'x. coiiipriNU as a gcnuml turiii all platoH bctwueii llu> liii.><als ami
orals, intonadially disposed. Sonu of tliom aro disfiiijruislnMl at* iiitiT-
brachials, otliors as inforaiiibnlacrals. Tho iiitcrhrachials aro coni'iiod to
tlio dorsal cup, Tho iutoniiiiliiilacrals occupy tho spaces hetweoii tho am-
bulacra. Tho intera.xillarios, consisting of the intonlisticlials and intor-
palmars, aro locatod within the axils of tho Hocond, third, and Miicceoding
onlors of brachials respo(!tively. Tho anal plates aro restricted to tho
poitorior interradiiis supporting tho anal tube. Another system of small
plates occurs in tho Acrocriniilie, where they form a wide bell inter-
mediato between the basals and radials.

In nearly idl Crinoids, recent and fossil, in which tho free arms do not
start directly I'nmi the radials, the lower arm joints are incor|)orated into tho
calyx, either by soft tissues or by means of plates. The latter are exceed-
ingly variable in form and character, being in some groups well developed
and rigid ; while in others they aro irregular, ill-formed pieci's, or mere liine-
Htono particles, resting within soft tissues. The gieat variation observable in
tho structure of the plates among dillerent groups led to the belief that tho
rigid and regularly arranged i)ieces, which are so characteristic of the Came-
rata, did not belong to the same system of jdates as the irregular, small
pieces which unite tho rays of recent Crinoids ; and Dr. P. II. Carpenter
applied to the former the term "calyx" interradials, as opposed to tho
interradial plates of the "disk."

A somewhat similar distinction was made respecting the plates which form
the ventral pavement. The heavy, rigid pieces of Palaeozoic forms were
called " vault " plates ; and the small, irregular pieces of later and recent
Crinoids, "perLsomic" or "disk" plates. The term "vault" was generally
applied in ca.ses where the month and food grooves ore permanently closed,
and " disk," where the mouth and food grooves aro open.

In the Camerata, tho interbrachials are nearly always arranged on a
definite plan, and are stout, large, and united by close suture, making the

ill

106

THE CRIXOIDEA tAMERATA OF NORTH AMERICA.

whole test, to the bases of the free arms, extremely rigid. The interbruehial
plates of the regular sides generally coinmeiice with one plate, which in most
families rests upon the radials and between the costals. It is usually fol-
lowed by two in the second row, and two, tliree, or four, according to spe-
cies, in any succeeding ranges there may be. The posterior interradius is
fre(iuently wider, and divided vertically into two halves by a continuous
or interrupted series of anal plates ; but it may be constructed like the other
four. In the Platycrinida3 and IIe.\acrinida3 the first row consists of three
pieces, which are for the most part neither entirely interbrachial nor entirely
interambulacral. In the Rhodocrinidaa the first plate interradially disposed
goes down to the basals, thus separating the rays to their full length. This
first plate is therefore not strictly interbrachial in po.-'ition, as it lies below
the horizon of the lowest brachials ; nevertheless it unquestionably belongs
to the same system of supplementary plates, which in this group extend
down to a position between the radials. There is some variation in the
extent to which the radials are parted by these intervening plates. In some
species of the Ehodocrinida?, exceptionally, the radials are only separated to
half their length, the variation occurring among different specimens of the
same species, and even in different areas of the same specimen. We find it
convenient to call these plates interposed between the radials " first interra-
dials" where it will avoid circumlocution. The interbrachial and interaxillary
plates of the Reteocrinida3, contrary to those of all other Camerata are in-
formed, and irregularly arranged.

The interradial plates occupying the ventral side of the calyx are as rigid
as those of the dorsal side, but are as a rule less regularly arranged. They
either extend up to the orals, or, when these are not represented, and the
ambulacra are subtegminal, they cover the whole tegmen, leaving no opening
except the anns.

At the inner floor of the tegmen, we find in most of the Actinocrinido3
and Batocrinidoe shallow grooves or open galleries, which are well shown by
the natural casts figured on Plate IV. Figs. 1, 2, 4, 5, 6, and 7, in which they
are represented by the elevations. These galleries pass out from near the
centre to the arm bases, and lodge the ambulacral tubes. Alongside of them,
and sometimes covering them, there is frequently in both families — but, so
far as observed, only in certain genera — what appears to be a second integu-
ment (Plate V. Figs. 13, 15, 10, and 17), lying parallel to the inner floor,
which was formerly supposed to represent the ventral disk. The outer

MORPHOLOGICAL PART.

107

integument was regarded as a structure sui ffcneris, to which the term "vault"
was applied. The inner integument appears at first sight as if composed of
independent, ill-foruied pieces ; but ou closer inspection it is found that
these so-called plates are extensions from the plates above, and continuous
with them. Eu,;li lower part is connected with the corresponding upper one
by small surfaces or pillars, and joining by its edges with other like plates,
leaves open spaces or meshes along the sides. The inner portions constitute
a kind of internal lining or network, extending from the first costals and first
interbrachials uninterruptedly to the margins of the orals. In some speci-
mens only the pillars are preserved, the lateral extensions of the plates being
wanting ; while in others the fioor is almost entirely smooth. The latter is
the case in Cudocriims probosckhtlts (Plate V. Fig. 10) ; while in Tekwcrimis
rittlis (Plate V. Fig. 16), and in the specimen of Dori/criims {ibid. Fig. 13), the
grooves are formed into well defined tunnels. A further indication that there
were probably two integuments in some of the Camerata at least, seemed
to be presented by the ventral structure of Siphomcrinus armosiis from the
Niagara group (Plate XIX. Figs. .S a, b, c). Tliis species, so well known from
natural casts, has a largo, trumpet-shaped, subtegminal anal tube, which
crosses the mouth, overlies the upper ends of the ambulacral tubes, and is
continued subtcgminally all the way to the anterior side of the calyx, even
beyond the arm regions, whore it bends outward. The case is best illus-
trated if we imagine the disk of a recent Crinoid, witii an anal tube like
that of Anlcdon irffiilis (Chall. Rep, on the Comat., Plate XLVI. Fig. 2),
extended all the way out to the arm bases of the anterior ray, and covered
by a vauit.

It seemed hard to account for the facts presented by these cases, except by
the presence of two distinct structures covering the body cavity ; and upon
these specimens princip.ally we formed the opinion, in the first instance, that
the Camerata had a vault and a subtegminal di.sk, and that the vault was
a structure without a parallel in recent Crinoids. The evidence appeared
to be conclusive that the disk was subtegminal, in some groups at least, and
this, which had been generally acknowledged by leading authors, led us to
believe that in all Camerata the disk was roofed over by a vault. In fact
this conclusion seemed to be corroborated by the nature of the plates, Avhich,
although varying considerably in size and number, arc arranged in all these
Crinoids on the same genernl principle, forming in all of them a compact,
rigid test, with the mouth and food grooves perfectly cIo.sed.

108

THE CUINOIDEA CAMERATA OF NORTH AMERICA.

Carpenter * held the same opinion aa to the vault of the Actinocrinidoo.
but he believed that the " vault" of a Platycrinoid " corresponds collectively
to the orals, interradials, ambulacral and anainbulacral plates of Ncocri-
noids." He agreed with usf that the calcareous network beneath the
" vault " of an Adimcrinua " corresponds to the limestone particles on the
surface of the internal casts, and represents the anambulacral plates de-
veloped in the perisome of recent Crinoids." He also admitted " the com-
plete resemblance between the ventral perisome of a recent Crinoid and the
upper surface of the body beneath the vault of an Ac/inocriiius." " The vault
and ventral disk," he said, " are to my mind entirely distinct structures."
Of the vault, he said further (p. 172) : " I believe the oral or actinal system
forming the vault of Ac/iiiocriniis to have been devcloiied on the left larval
antenier, in exactly the same way as the apical or abactinal system is
developed on the right ; but the oral system, instead of being limited to five
oral plates, as in Neocrinoids, reached a very extensive development, so that
in its conipletest form it represents such a parallel to the apical or abactinal
system as is to be met with in no other Crinoid." From these passages and
others in the Ciiallenger Report, it appears that Carpenter, as well as we,
supposed that in Adlmicrinm all plates of the calyx up to the arm bases were
abactinal, and all constituting the ventral side actinal ; not only the orals
and radial dome plates, but also the so-called interradial dome plates or
interambulacral pieces.

We retained the above mentioned opinion until 1881; but afterwards
our views were materially changed respecting the interradial dome plates,:}:
which we no longer regarded as actinal structures, but took to be con-
tinuations of the interradial plates of the dorsal cup, and as fundamentally
identical with them. In considering the matter in the first place, we had
not overlooked the fact that in many of these Crinoids, throughout different
groups, the covering plates of the ambulacra are exposed at the surface, and
as such would form a part of the " vault."

It is a striking fact, in the Crinoids as elsewhere, that some characteristics
which are of the greatest importance from a morphological point of view,
prove to be of comparatively little value for classification. This is the case
in a marked degree with the ambulacra of the Platycrinidre and Actino-
crinidae, which are found to be tegminal and also subtegminal. In the Platy-

• Clmll. Rep. Stalked Crinoids, pp. 172-180.
t Clmll. Rep. Stalked Crinoids, pp, 105, IflO.
X Revision, Part III. pp. 10-27 (Acad. Nat. Sci. Pliila., pp. 238-249).

MORPHOLOGICAL PART.

109

crinidaB, the covering pieces are generally exposed in the calyx, while in the
ActinocriniiltD they are as a rule hidden from view. But occasionolly the
opposite is the case, and even among species of the same genus. Actinocriims
dellavis, from Belgium, has well defined covering pieces passing out from the
outer edges of the orals ; while almost every other species of Ac/iimriiiits has in
place of them radial dome plates of the first, second, and third order, accord-
ing to the number of bifurcations in the calyx, riiijselucnmis, which is but a
modified Adinocnnus, has in some species orals and radial dome plates ; while
in others the whole ventral surface is covered with small, irregular pieces.
In Adinocnnus mnUinuUutm, the entire tegnien consists of only a few unusu-
ally large interradial plates, which interlock with those of the dorsal cup.
But the interradials in most of the Actinocrinidaa pass insensibly into the
tegmen, there being no dividing line ; while in Batocrinus generally, Init
not always, the interradials of the dorsal side are distinctly separated from
those of the ventral side by the arching brachials, — a structure which led us
at first to suppose that the plates of the two hemispheres were morphologi-
Ctally distinct.

Similar variations occur among the plates of the tegmen in the Platy-
crinida) and Hexacrinidoe. In some of their species the pavement is made up
entirely of massive plates, in others of comparatively thin pieces ; while in
still others the ventral surface is occupied almost exclusively by the orals.
In both groups it is absolutely impossible to draw a dividing line between
interbrachials and interambulacrals. The plates constituting the first row,
which generally consist of three pieces, are peripheral and partly interam-
bulacral, and those of the succeeding rows strictly ventral. The plates of the
second and higher rows, when such are present, interlock with those of the
first row, like the interradial plates of the dorsal cup in an Acthiocrmis.

The condition of the ventral pavement in the Mclocrinidte, Ehodocrinida?,
and Tliysanocrinida) is similar to that in the Actinocrinidoe. Their lower
interbrachials are definitely arranged, and there is no line of demarkation
between the plates of the two hemispheres, except that produced by the
arms, which pass out between them. In the Rotoocrinida), as in most of the
other Silurian Camerata, the whole ventral surface is covered by minute,
irregular pieces, and similar plates, with a few somewhat larger ones scattered
among them, are interposed betweeti the rays from the basals up.

It seems to us perfectly clear from the structure that all interradial and
interaxillary plates, not only in the Camerata, but also in all recent and fossil

110

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

Criiioids, where they exist, are auxiliary pieces, wiiich increase by multipli-
cation in the growing animal, filling up spaces between the rays and their
subdivisions. They increase primarily in an upward direction, but partly by
intercalation, secondary plates being introduced between the primary ones.
It is owing to the intercalation of these secondary pieces that the arrange-
ment of the interradial plates in the upper rows is less regular than it might
otherwise be. In the simpler forms such pieces are wanting, or only occur
close to the arm bases. In some species, however, they are quite numerous
in the dorsal cup, as well as in the tegmen, and in the Retcocrinida) they
constitute the greater part of the interradial and interaxillary areas. In this
family small pieces continually formed in large numbers in the growing
Crinoid along the margins of the radials and brachials, and between the
primary interradials, so as to isolate these from their fellows and from the
plates of the r.ays (Plate IX. Figs. 1 c, be).

The interradial plates, as already stated, are continued into the tegmen.
This may be readily perceived in species which have but one or two bifurca-
tions in the calyx ; but in the more complex forms the primary structure is
frequently obscured by the introduction of secondary pieces, giving the im-
pression that the plates of the two hemispheres were structures morpholo-
gically independent. J^ooking at a specimen of S/rofocrimis, with a broad
flanging rim, its hundred and more arms crowded around it, and its thousands
of minute "vault" plates, growing smaller outward, and n^t connected with
the interradials of tlie dorsal side, it is not surprising that such an impression
should be created.

To understand the structure of Siroiocriiiiis, we may refer to that of the
allied genus Sfc(/anocriiii(-s, in which in like manner the arms branch oft' alter-
nately like pinnules from the two main divisions of the rays; but while in
Strotocrinus the lower parts of the arms are incorporated into the caly.x, and
form a continuous rim from which the free arms start off, in Sleganocr'iims
the two divisions of the rays, bearing their small alternate arms, remain per-
manently free, and extend out laterally as tubular appendages of the calyx.
It is now very significant to find that in Stcf/anocnmis the interradials of the
dorsal cup meet those of the tegmen in such a manner that it is absolutely
impossible to draw a line between the plates of the two hemispheres (>S'/<v/«»o.
crimis prnfagonm, Plate LXI. Fig. 3 !>). This case is the more instructive,
because Sleganocrimis, with its free arms, may be regarded as representing
an early stage in the developmental history of Strotocrinus.

MORPHOLOGICAL PART.

Ill

A structure similar to that of Stegamcrinus is fomiJ in all Camerata in
which the arms are free from the tiistichals up ; and from this condition all
gradations can be traced to the complex structure of Slrotocrlnm. The plates
of the dorsal cup and those of the teginen are undoubtedly parts of one ele-
ment ; and although they are introduced respectively at the actinid and
abactinal sides of the calyx, the plates of the one side cannot be regarded
as strictly abactinal, nor those of the other as actinal.

Referring again to Pktb/crinus, Carpenter* said that the series of inter
radials found in the peripheral portion of the vault (tegmen) — by which he
meant the zone between the proximal dome plates (summit plates) in the
centre and the calyx interradials (of the dorsal cup) — belong to the same sys-
tem of interradial plates as the single large interradial in Q/athocriiius. And he
continues: "I do not myself think that the vault of a Plali/crinUc was exactly
of the same nature as that of an Acliiiocrinite, i. e. that it covered in the whole
of the visceral mass and the ambulacra on its upper surface. For if the
alternating dome plates represent the covering plates of recent Crinoids, as
Wachsmuth suggests, then all the periphery of the dome, outside the apical
dome plates (orocentral and oral-i), must be the real ventral surface of the
body, and not a tegmen cuh/cis as in Adinocnnus." And in alluding to the teg-
men of Mursiipiocrinus, ho said :t " I have a very strong impression that the
so-called vault of this genus is really the strongly plated ventral peris "..e, in
the centre of which the remains of the orals (apical dome p^ites) are j)erhaps
to be found. I cannot see any such essential difference between it and the
plated disk of Pcntacrimis W/jvilk-thomsoni or of many Anteduns (Plate XVII.
Fig. 6 ; Plate LV.) as would lead to the supposition that the homologue of
the latter is to be sought for beneath the vault of JfarsKpiocrhnis." He then
alluded to the closure of the mouth, and to the covering pieces of the ambu-
lacra, which may have been immovably closed down over the food grooves,
saying: "They were thus converted into tunnels, but were still 'external,' in
the sense of not being covered hy a ' tegmen,' as those were which formed
the tubular skeleton beneath the vault of the Actinocrinidne." That is to
say, in short : Vault and disk are entirely distinct structures ; and the
ventral surface of one Pakieocrinoid represents a disk because the am-
bulacra are external, while that of another is a vault because they are
subtegminal.

• Clmll. Rep. Stalked Crinoids, p. 17S.
t Clmll. Rep. Stalked Crinoids, p. 170.

112

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

We hiive already pointed out tliat the covering pieces are exposed not
only in the Platycrinidic, but frequently also in other families of the Canie-
rata, — exceptionally even in the genus Actiiwcriiius. If it were true that in
Crinoids in which the disk ambulacra are subtegminal, the integument which
covers tiieni is a " mult," and, on the contrary, in those with ambulacra ex-
posed, or " exteriial," a did; it seems to us that the two forms should be
separated as distinct orders, and it would follow that our present classi-
fication of the Crinoids is arbritrary and worthless. These considerations
produced in our minds a firm conviction that the integument in both cases
must represent the same thing, being either a vault or a disk, — the plates
either all vault pieces or all perisomic.

In some species of Platijcvinm the ambulacra make their appearance, not
at the margins of the sunimit plates, but at some point intermediate between
tlio orals and the arm bases, from beneath the upper ring of the interradial
plates. In these species, applying Carpenter's interpretation, the lower inter-
radials would be perisomic, for tliey expose the ambulacra ; but the upper
ones vault plates, because they do not. In Plcrolocriims, the last survivor of
the Ilexacriuida), a very higldy differentiated form, the tcgmen, according to
Carpenter,* '• seems to have had a closer resemblance to that of Actinocnnus
than is the case in most Platycriuida), for it had rjidial dome plates of tie
first, second, and even occasionally of the third order." In other Platycri-
nida) tiie oral system, he says,t sooner or later came in contact with the
alternating series of ambulacral plates. " There was a membranous disk,
the radial regions of which were travensed by the ciliated food grooves
beneath the ambulacral skeleton above ; while the interpalmar regions sup-
ported the interradial plates of the vault," Further on he explains that
the vault of the Plat^crinidoc is not a true vault, or tcgmen cafz/cis, like that
of the Actinocrinidtc, but corresponds collectively to the orals, interradials,
ambulacral and anambulncral plates of Neocrinoids ; contrary to the vault
of Ac/iiiocrimis, which not only covers in the food grooves themselves, but
also their skeleton of alternating plates, together with the origin of the
ambulacra and the plated interpalmar areas of the disk.

We never imagined that Pkf//cn'iiits had anything but a membranous
disk, which, we thought, was continued underneath the interradial plates
all the way to the arm bases. Neither did we suppose it had any further
plates above the food grooves than the alternating pieces ; nor that the

• Chall. Rep. Stalked Crinoids, p. 177. t Ib'^-. PP 179-lSO.

MORPHOLOGICAL PART.

113

latter were true vault plates, aa Carpenter inferred wc did. We held that
while in the vault of the typical Ac/mocnnua the iuterradial dome plates
meet over the ambulacra, in Pla/i/crimis these })lates opened out so as to
oxpo.se the covering pieces, and that the.se were gradually incorporated
into the vault. In a typical Platycrinoid, the covering pieces are so
modified as to lose almost their original character, being as large and
nearly as heavy as the surrounding plates, and they are united with one
another, as well as with the latter, by close suture. In some of tlie later
Platycrinidas they even may have been separated from the food grooves,
for in the internal casts they lefl no impressions ; while in casta of Actino-
criiius from the same localitie.", and in casts of certain Silurian Plntycrinida?,
tlie outlines of the ambulacra are generally sharply delineated (Plate LXXV.
Fig. 14).

Carpenter probably supposed the ventral structure of the Mclocrinidto
and RhodocrinidoB to be in the same condition as that of the Actinocrinida)
and Platycrinidoc respectively, that is, a disk when the ambulacra are ex-
posed, a vault when they are concealed. He alluded to G/z/piocrimis in
connection with the Reteocrinic'iaa and Ichthyocrinidoo, in all of which the
ventral pavement is composed of an immense number of very minute,
irregularly arranged pieces. In the Ichthyocrinida! these plates are trav-
ersed by regular rows of alternating pieces, passing out from the oral centre
to the arms ; in the two other families, however, such alternating plates,
when present at all in the tegmen, are found only close to the arm bases.
Carpenter says respecting these groups,* " I venture to think that in the case
of Gli/ptocrimis, Rctcocrinus, Xcnocriniis, and also of the Ichthyocrinida', the re-
semblance to the Pentacrinidto, Apiocrinidie, iind Comatuloe, is such as to
leave no reasonable doubt that the so-called vault of these Palwocrinoids is
homologous with the ventral surface of the body in the Ncocrinoids." This
is true enough as to Taxocnnus and Oni/chocrinus, and probably the Ichthyocri-
nidne generally, in which mouth and food grooves are exposed, as we have
found out from actual observation ; but in the case of Gl//ptocrimis and Ifcfco-
crinus, there is nothing to prove it beyond a superficial resemblance of the
plates. Carpenter's argument lo,ses much of its force, considering that
among the Actinocrinida) within the same genus some species have large
plates, others very small ones, and the evidence seems rather to prove
that either these plates are all disk plates, or none of them are.

• Chall. Kep. Stalk. Crin., p. 185.
15

114

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Essentially tliffcrent is the vcntrul structiuc of the Fistiilata, which have
no intonadiul plates in the dorsal cup, the anal piece excepted ; hut those
plates are extensively developed in the legmen. Four of the intcranibu-
lacral spaces are raised but little above the level of the arm bases ; while the
posterior area is extended abruptly upward, and formed into a sac or tube of
various forms, frequently rising beyond the tips of the arms. This sac,
which may be regarded as a greatly extended anal area, and probably
lodged a large portion of the visceral mass, must not be confounded with
the anal tube of the Camerata, whicii contains simply the rectum. Tiie
sac is tubular, bnlloon-shaped, spiral, or club-shaped, and is generally com-
posed of longitudinal rows of hexagonal plates, which are often pitted at
their sides, or perforated by pores.*

The structure at the four other sides of the disk is rarely observed ex-
cept in the Cyathocrinidos, in which it was probably more substantial than in
the other families. In Cjuthocrinus it is well shown in our figures on Plate
III. Figs. 1, 2, 3, 4, C, 7, 8, to which we drew attention in our chapter on
the orals. There are six plates, interradially disposed, resting against the
inflected upper edges of the radials, their lateral margins covered by the
ambulacra. Four of them are larger, cordiform, and of equal size ; the two
others, which lie at the posterior side, are quite narrow, and enclose a large
perforated plate to which we have applied the term mculrcporilc. The sur-
faces of the four larger plates in perfect specimens are roofed over by num-
erous delicate pieces ; while the perforated plate is completely exposed
to view.

Ap to the relations of these plates various conflicting views have been
expressed. Wachsinuth, in 1877, supposed that the plates collectively con-
stituted a kind of consolidating apparatu.s, like that described b^' Roemer
and others in Cupressocrinus. We afterwards, supposing that there were five
plates, suggested that they were structurally identical with the deltoids of
the Blastoids, which at that time were regarded as homologous with the orals
of the Crinoids. Similar views were expressed afterwards by Carpenter,

• Mr. Batlier is of the opinion that the ventral sac of the Fistulata is not perforated, hut only pitted
(Geol. Magazine, >[ay, 1891, p. 233, and elsewhere). Tliis may he true as to Ci/athocriniix, Eiispirocriinis,
and possibly the Ci/athnerinidir generally, in wliieh very likely the madreporito performed tlie fnneliiins of the
tiibc-imres ; but we have tlie most complete evidence that among the Poteriocrinida;, in many cases, llie jiores
pass tlirongli tlie test. In some specimens in which llie lateral edges of the plates were exposed ]>erfeelly
free from the matrix, we have been able to trace the duets of the pores to the full depth of the pl:ites. They
are well sliown on Plate VII. Figs. 2i, 5, 7, 8, 9. Tiiat tlie openings are not visible iu most of the speei-
meus is due to their small size and probably also to the mode of petrifaction.

ii:

MORPHOLOGICAL PART.

115

Zittel, and Neumayr, who nil regarded the plates as orals. Plausibk- ns this
theory appeared to us at first, it involves serious morphological diiriculties ;
and in 1883, on discovering that the plates consist of seven pieces instead of
five, we abandoned it, in which we were 1 >wed by Carpenter. Since then
we have taken the plates to be interradials, although with some hesitation,
for they are not interbrachial, nor, strictly speaking, inter-ambiilacral, but in
part sub-ambulacral, and sub-tegminal. In tiieir position they rosonible
tlie first intcrradials of rialycrbuw, but the ambulacra of that genus rest
against the edges of the plates, and only the covering pieces are exposed.
In the Cyathocrinidao, not only the ambulacral jMcs, but also the ambulacral
vessels rest upon solid plates, and the small marginal plates on top of these
plates sustain toward the side- and covering-pieces the same r(>]ation as the
interradial plates of the Platycrinida) toward their covering pieces.

The presence of three plates at the posterior side, as against one at the
other four, would seem to indicate that they may be homologous with the
first row of interbrachials of the Batocrinidoo ; but upon closer examination
it appears that the two structures are not exactly parallel. We have no
doubt that .ilso in Cyatliocrinus, as in the case of Batocrimts, the posterior
plate is broken up into two pieces by the middle plate ; but this plnte in
Cyatliocrinus is a madreporite, while that of Batocri'mis is a supplementary
anal. The former constitutes the xippcnnost plate of the posterior inter-
radius, being separated from the first anal plate by the full length and
depth of the sac; the plate of Batocrimts, however, which rests directly
upon the anal, represents the loivest plate of the area.

Obscure also are the relations of the small marginal plates, which in
Cyatliocrinus overlie the larger ones, and which occur only at the four smaller
sides of the disk, leaving the surface of the madreporite at the fifth side ex-
posed to view. The only plausible explanation we can find for this structure
is that these plates represent the higher disk plates, which for want of .space
overlapped, and gradually covered the larger ones ; while those of the pos-
terior side, instead of overlapping, were carried upward, and formed into a
sac or tube.

The large interradial plates of the CyathocrinidoB apparently have close
affinities with the deltoids of the Blastoidea, and Carpenter and Bather*
proposed to apply also to the plates of the former temporarily the term
" deltoids." The plates of both groups rest upon the radials and support

• Ann. and Mag. Nat. Hist., 1S92, p. U.

116

THE CRINOIDEA CASIKRATA OF NORTH AMERICA.

I' '.

tlio onils ; but while those of the Cyatliocrinidoe enclose a madreporite, those
of the liliistuids enclose nn iinal piece. The conditions nre thus not cxnctly
alike, and we do not see why that term is any niore appropriate than " in-
terradials" — a term which has the advantage of being more general.

In the Ilybocrinidiu the posterior side of the disk is less elevated than in
the Cyathocrinida), rising but little above the level of the other four sides.
The ambulacra are tegminal, and apparently rest upon the lateral margins
of the four largo interradial plates. There arc no orals, the median portions
of the disk being occupied by large covering pieces.

The ventral pavement of the Anouialocrinidac, which we examined in
a fine specimen from the Museum of Comparative Zoology, difTers essentially
from that of the two preceding families. It consists of lather large, moder-
ately thick, irregular pieces, five or six deep, which decrease in size toward
the centre and cover the i)eristome ; no orals being distinguishable. The
outer of these plates rest against the large incurved limbs of the radials,
forming a wide and deep sinus for the reception of the ambulacra, which are
on a lower level than the other disk plates, and in the Cambridge specimen
of a different color, and thereby readily recognized.

The tegmen of the Potcriocrinidto has never been foimd in perfect pres-
ervation. We hoped to find it by dissecting a number of finely preserved
specimens, but the sacrifice was only rewarded by finding in a single instance
a few small, scattered plates; from which we conclude that the covering was
of very fragile construction. The form and size of their ventral sac is ex-
tremely variable ; extending in some cases beyond the tips of the arms, in
others consisting of merely a short cone. In some of the genera i* is tubu-
lar, in others club-shaped ; in some balloon-shaped ; in some even .■spiral the
whorls of the coils either united or free ; but in all cases, so far as we know,
the plates are arranged in vertical rows, which sometimes diverge at intervals,
and apparently in all of them the edges of the plates — not their substance
— are perforated by pores or clefts.

A porous sac is also found in the BelemnocrinidoB, and probably exists in
the Heterocrinidoe, but nothing is known of the other disk plates in these
families.

In the Encrinidae, according to Wagner,* the ventral disk rises to about
the height of the second costals, where it contracts abruptly to one half its
diameter at the base, and is surmounted by a small cone. The peripheral

• Zeitschr. d. Deutsch. Gesellscli., 1887, pp. 822 to 823.

MORPIIOI.n(.^\L .'ART.

117

pnrt consists of Htnnll limestone partii, -s, or irregi lar plutos. nn<l was ovi-
dontly (lexil)le ; wliilc the conical part, wliieli is coinjwsod ol rpor piowf*
appears to be almost riyid. Notliing is said about atiibiilnrra, whicli v^^^
probalily not visil)le in the specimen. That the cone ro] -^Mit" a ^1 rt
ventral sac, and that the allinities of the P]ncrinidn) are with llio Fisiiitata.
and not with thi) Apiocrinidtu and other Neo/oic Crinoids as hen'tufoco,
supposed by Miller, Miillcr, Zittcl nnd Carpenter, U clearly shown from
Wagner's description.

Among A|>iocrini(ln) do Loriol observed the togmen in Apiorr'nvii^ rnissij-
mini* a species with larj^'c, massive plates interposed between the rays, and
in which tho plates of the cup gradually pass into the tegmen, which consists
of rather heavy plates. Tho interbrachial plates were regarded by Carpenter
ns "calyx" interradials, i n. homologous with the interbrachials of the Acti-
nocrinida', the plates of tho tegmen, however, as "disk" plates, — a position
which was controverted I)y us.t We asserted that if those plates were
" calyx " interradials, they should bo followed by a " vault ; " but if tho
tegmen was a disk, then the plates between tho rays also had to bo con-
sidered as disk plates. We came to this conclusion upon ascertaining that
the plates of the tegmen form a continuation or extension of those in the
cup. The plates of the two hemispheres in most cases pass imperceptibly
from one into the other, and have the most intimate relations.

Aplncrlmin. is not the only Neocrinoid genus as to which there have been
doubts respecting the homologies of tho interbrachial plates. GKddinh'rriiuis
is morphologically in exactly tho same condition, and the recent genus Thwi-
matucrimis has five largo plates interposed between the radials, resting upon
the basals, and followed by very minute, irregular pieces, which j;r,adually
pass into the tegmen. Also in many of the IchthyocrinidoB the plates be-
tween the rays are large and heavy; while those of the tegmen are ill-formed
nnd unusually small. Ghjptocrimis has minute, irregular pieces in the teg-
men, and well defined and regularly arranged plates in the cup. In all these
cases Carpenter took tho larger plates to be " calj'x interradials," but called
the others " disk plates," although tho former occupy relatively tho same
position as the smaller ones, and as the disk plates of the Comatulnc, CaJamo-
crinns, nnd the Pentacrinida?. Our recent studies show plainly that neither
tho condition of these plates, nor the presence or absence of the ambulacra

• Pnlcont. Fratif ., Ire s^ric ; Aiiim. Invert., Criiioidcs, p. 272.
+ Revision, Part III., pp. 63, 72, aud 137.

lis

THE tUIXOIDKA CAMKUAIA OF NORTH AMKRICA.

t \

I ;

in tliu tegiiti'ti, uimbloM im tu di><i'riMiiniito bt>tweon purixuinic mid vault pieccB;
ami tlii.'* led im tu iii(|iiirc> wliutlivr hucIi a dUtiiictiuii uctiially vs'n^ia iit any
group.

After it wax demonstrated that the ventral Murfaco of Taxdcriiiiin i« a tnio
ili.sl<, we liecaine couviiieed tiiat our views reMpeeting vault and disk would
have to l)u iiioililied as to other groups also, or be altogether almudoued. The
latter was done in 1892, in a paper on " The I'erisomic Plates," * in whieh
wo endeavored to show that the so-called "vault" of the older Crinoids
is a inodilied disk. This interpretation has since been necepted by Agassiz,
Carpenter, and Huther, who agree that the use of the term "vault" should
1)0 abandoned in a morphological sense. The modifications that took place
arc most apparent among the Camerntn, in which there in a marked increasu
in the si/e and rigidity of the plates, which reached itM culmination among
Carbonil'erous forms.

The t<'j;iuen of Paheozoic Crinoiils is often formed into ridges, which
diverge from near the centre to the arm bases. These ridges, which aiu
liest defined, and occur most freriuontly, among Silurian Cnmerata, are formed
cither by covering pieces or the interambulacral plates. Such ridges also
occur uiion the di.sk of the Couiatuloj, but they are formed exclusively by
the amliuliicral plates. Among the earlier forms ridges of this kind have
been observed in Actituirrliuis (j)ilnijH(iii(juliiiis,1[ Ifidinicriinis anHtftis.^ Mursii-
jiiocn'iiiis (lijinssns,^ Jftrf<iij)ii)rrliiiis rdilldtiis (Plate VIII. Fig. 15); and
Pldtijcriiiiifi symmctrlcHs (Plate LXIX. Fig. Ifi) ; in all of which the mouth
is closed either by the orals, or in their absence by the uppermost covering
pieces, which interlock with those of adjoining ray.s. Very prominent ridges
occur also upon the disk of TaxorriiniH liitirinaliiis (Plate III. Fig. 11), in
which, fontrary to the preceding forms, mouth and food grooves arc opened
out. The ventral structure of this species bears a remarkable resemblance
to that of the young Pluti/criiiHH mjmmetrkus (Plate LXIX. Fig. Ic); nil
that is recjuirod to convert the "vault" of this Phiti/criniis into a disk like
Taxocriiiiin, is that its orals should be parted enough to let the ambulacra
pass in to the centre between or over their edges. Its resemblance is equally
striking to the recent Culamocrimdi and Ilijocrbuis ; n slight receding of the
posterior oral and movable covering pieces would bring the three forms sub-
stantially into the same condition, all of which shows that the closure of the

• Procml, Acnd. Nnt. Scl. Pliila., pp. 315-375.
+ Icoiiditr. Clin. Siipc, Plate XVI. Fig. 28.
§ Ibid., Plate X. Fig. 10.

t Ibid., Plate XXVII. Fig. 5.

^|k

M(HU'II()I,0(iK'AI- I'AHT.

110

mouth in tlic oMit Ciiiioids is not acconiplislu'il hy miy mlditioiiMl ,«i't of
pliiti'H, but hy tilt' pliitcM wliifli in rocont CiinoiilM .xini'oiinil tin* mouth.

CiiHCH in whicit the amhiiiiicni enter tlie tegmun from licinnili what
>voro funiiei'ly ciilled the internulial donu' plitteM, are I'oinid in almo.«t
every family of the (.'ami'rata. They oceiir more fri'ijin'Mlly aiiioni: jjeiieru
in wiiicli the ventral Hurfaeo is paved liy Hmall irregular pieces. ^u(h as
(I'l^jifiifriiiiis, lidiiirruiiifi and Airhu'drriniis ; hut alno in otht-rs. A mo.xt
instruetivo ca-ie of this kind is preMented hy n rather younj,' ^-pecimen of
Mtyintorrlinig miliil'm (Plate XLVII. B'ign. ^n, l>), in wliieh not oidy covering
jjiccex, hut well dermed side pioeos enter the calyx. The ventral pavement
connists of moderately large, irregularly arranged plates, whieh ;:radnally
decrease in .size toward the arms. The tegmen is perfectly Hat, except near
it8 outer margin, where it is distinctly plicated to form the large openings
for the ponderous arms. At tin- iinier Hat portions the aml)ulacra are con-
cealed, hut at the plicated outer part hotii covering- and side-pieces come to
the surface, and are visible for some distance. It is now quite instructive
that in another more adult specimen of the .same species (Plate Xl<\'ll. Fig.
G) the parts of the amhulacra which in the former Hi)cciinon were exposed,
are roofed over from both 8ido8 hy interambulacral plates of snhseiiuent
growth. This observation throws important light upon the development of
the so-called vault of the Camerata generally. It shows that the same system
of plates, which in a young specimen is in p^irt /«^tv-ambidacral only, may
gradually become .'(/^^nz-ambulacral in apothei .

Wo find a somewhat dilTerent structure m a finely preserved adult speci-
men o( JfnjistocrtHKii Kransi (Plate XLVII. B'ig. ]f>), in which in tliroc of its
rays two series of large, nodose, alternating plates pass out from near the
orals in the direction of the ambulacra. The series are freqiicntly inter,
rupted by .small, Hat pieces, which are interspersed among the larger
ones. In some places the arrangement of the larger plates, which are
evidently covering pieces, is ns regular as in any Phttijcrhms ; but at
others, owing to the interference of the smaller plates, quite irregular,
especially in the two rays to the right of the anus, where scarcely any
two of those plates are continnou.s. It is most remarkable that in no
two specimens of this species is the arrangement of the covering pieces
alike. In .some of them, only the five large bifurcating plates, the ,«o-callcd
radial-domo pieces, arc in view, followed by ten others of a second order.
The ventral structure of this species not only ofTers a good proof that the

'! '

£'l !

120

THE CUINOIDKA CAMKRATA OF NORTH AMKRICA.

so-calletl nuliiil dome plates, aw before suggested, are extravaganlly developed
covering pieces, but indicates that the "vault" was I'ornied by a gradual

of the hiteninibultj

alony the li

jI" the anibulii

ithei'

rxtensum oi the inteninibulacral areas along the Inie ol the aniijulacra, either
covering them entirely, or encroaching upon them and leaving the more
prominent plates exposed.

In GI)/ptocrhu(s and Jictcocrhius the toginen is essentially in the same
condition as in JIc(jlstucrint(s nuhilin, but no orals are distinguishable, and
the whole ventral surface, including tiie median portions, is covered by
minute granular pieces. The middle part is evenly convex, but toward
the perii)liery there are ridges leading to the arm bases, and on top of
these ridges the covering pieces are exposed. In the median portions the
.".mbulacra were evidently subtegminal. being rooled over by superimposed
inter-ainbulacral plates, which form a continuous intcgmnent over them.

A careful study of the difleront tcgmens which are foiiud among the
various families of the Camerata shows that the ambulacra, as a rule, are
subtegminal in species with a high dome or bulging at the arm bases, but in
species with a llat or depressed surface they are generally tcgmini'.l, or
become tegminal before entering the arms. They are expo.sed in forms like
"Actiiitivriiiiis" qiiinqu(iii(jiihiri)i, Ildbrocriniis uriHtttd^, Mitrmijiiocrhnis dcjjiXfisiis,
and (UiijitihTinuti unnitKS, — species with a low disk ; but they are necessarily
subtegminal in genera such as Cavturrinitti, Slj)JtoHucrliii(!i, etc., in which the
tegiiieu is high and conical. The condition of the ambulacra, therefore,
whether tegminal or subtegminal, does not represent an es.sential structural
feature, but is a natural consequence of dilferences in the form and construc-
tion of the teginen in the respective species.

jSow if it is true that a plated integument was formed in GI>/j)tocri)ius
and Jlt(jisiiicruuis by the profuse development of the interambulacral plates,
and their gradual fusion along the line of the ambulacra over a part of the
disk, it would seem to follow that the more substantial vaults o( Actinocrinus,
Butocriinis, and Plti/scfovriiius may have originated in ii similar way, and that
the body of these forms also was covered by a single set of plates. This
seems to be confir'ned by a very instructive specimen of Phi/sducriinis, in
which the delicate structure at the inner door is shown in excellent preser-
vation (Plate V. Fig. 14). The specimen has the great advantage of being
free from any silicious coating, such as obscured the structure in previ-
ous specimens of this kind. The outer surface of the tegmen is composed
of moderately large, smooth pieces, of irregular form, closely fitted together

MORPHOLOGICAL PART.

121

at nil sides. There are no orals, but near its outer margin tliore are radial
dome plates of a first and second order, which are readily rccogni/.ed by
their largo size and greater convexity. Other ainbulaeral plates are not
visible. Examining the inner floor, we find the same arrangement of plates,
and actually the same plates as at the outer side, but the general aspect is
tot4dly different. They look like sharply delineated stars, with as many rays
as there are sides to the plates. There are abrupt depressions between the
star-rays, which on meeting corresponding depressions of adjoining plates,
form deep, sometimes cavernous pits, more or less undermining the plates,
and which seem to have communicated with one anotlier by imbedded pas-
sages all along the teguien. The star-shaped plates extend over both the peri-
stome and ambulacra, being occasionally interrupted by small, supplementary
pieces, apparently solid. Thus the tegmen o( Plii/fctocriiiiix is not composed
of two distinct sets of superimposed plates, as heretofore supposed, but of one
set only, of which the plates arc solid externally, and perforated or honey-
combed throughout their inner portions. The presence of but one set is
further confirmed by the position of tiie ambulacra, which follow the inner
floor. This is of importance, for if the upper or solid part, as was supposed
to be the case in the allied BiiforriiiKs and Artiiiocriinis, represented a vault,
and the inner part a disk, the ambulacra should lie between them ; whereas
in this case, lying below them both, they would be covered by two integu-
ments, first by the overlapping interainbulacral plate.s, and then by a vault,
— an arrangement in the highest degree iinprol)able. The ambulacral skele-
ton itself is not preserved in the specimen, but the place it occupied is clearly
indicated by .shallow grooves, formed by a thickening of the plates all along
the interradial spaces.

The internal structure of Fliyiictocrii)t(s gives us the key to that of Bato-
criiius, Donjcrlnm, Actinocrinns, Teklorriniis, and of the Camerata generally,
in all of which, as wo no longer doubt, there is but a single integument ;
and the part which wo have heretofore regarded as a disk forms a portion
of the same set of plates, which are perforated at the inner floor so as to
produce the numerous caverns and passages above described. Those pas-
sages and pits may have served for the free circulation of water, and we
think it highly jirobable that the older Crinoids had a very complex .'ascular
water system, extending all tlie way from the interradial plates of the dor.'^al
cup to the top of the ventral disk. This complex system was probably
not required in recent Crinoids, in which many of the plates are perforated

i ,
f ^

)

f '

122

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

[■^ \ t

11 i

througliout, by means of which the surrounding water is brought in direct
contact with any part of the body.

There are good reasons for believing that in the Camerata the water for
respiration was introduced near the arm bases through small openings, de-
scribed by us as respiratory pores, and then followed the canals and passages
along the test. Such openings have been observed not only among the Actino-
crinida3 and Batocrinida), but also among the Melocrinida) and Rhodocrinida\
In tiie genus Dohttocrlnus, they are large and slit-like as in Ophiurids, in Batu-
crinits and Actinocrinus round, and in Gilbertsocrinits at the outer end of long
tubes. The openings are always located between the rays and their main
divisions, a little above the arm regions. Some species of Dolatocrinun have
from four to six to <^^^c^\ interradius, and two to four to each interdistichal
space, all arranged horizontally. In Dolatocrinus this vascular system prob-
ably extended only over the peripheral portions of the disk, for the inner
floor at the middle portion is perfectly smooth in the specimens. In Bato-
crimis and Tcleiocriniis it probably extended to the outer margins of the orals
(Plate V. Figs. 16 and 17) ; while in Physctocrinus, when the orals are un-
represented, it apparently occupied the whole tegmen.

We now come to the ventral structure of Sijjhonocrinus. It will be
remembered that in S. armosus not only tlie .ambulacra, but large portions
of the anal tube, are subtegminal, and that the latter lies across the mouth
and covers portions of the ambulacra. The tube, however, in two other
species of this genus opens out centrally, thus showing that the subtegminal
condition of the tube had no important bearing upon the general structure
of the disk. As we understand the case, the anal tube, which is actually
the outer end of the hind gut, in place of becoming free ind piercing the
central part of the disk as in the other two species, was roofed over in
S. armosKS by the interambulacral pieces in a somewhat similar manner to
the calyx ambulacra of Merjistocrinus.

Now if it is true that in forms like Physetocrinns, Batocrinm, Actinocrinus,
and Siphonocrinus, there is no second integument, .'t may be considered as
proved that a " vault," as an independent structure, did not exist in any of
the Camerata, nor, in fact, in any of the other groups, and that the structure
to which the term has been applied in these forms was evolved phylogenet-
ically from the disk of the primitive types, of probably Pre-Silurian time.

The disk of the Fistulata also experienced notable changes in its paloeon-
tological development, but these took place on different lines. The plates

*!S

:|l

MORPHOLOGICAL PART.

123

of the tegnien at no time attained the rigidity and large size of that in
the Camcrata, nor did those of the doraal cup, with the exception of
the anal plates, undergo any material alterations. It was the ventral sac
which gave to this group its characteristic feature. The sac in the earliest
forms was quite small, but it soon attained such enormous dimen.sions that
already in the Silurian it constituted the greater part of the cal^x. At the
close of the Carboniferous, however, it dwindled down almost as rapidlj- to
its former insignificance, so that it is represented in Cromifocrimis, L'lijKwhy-
crimis, Erisocrimts, and Encrimis by a very short cone. The resjjiration of
the Fistulata was apparently directly through the test, but only at the
posterior side of the calyx. It took place either by means of pores along the
sac, or by a madreporite placed in front of the sac. The respiratory pores
of the Fistulata only pierce the edges of the plates ; while the water pores of
recent Crinoids pass through the whole plate. The mode of respiration of
the Larviformia is unknown. They had apparently no openings in the
calyx except the anus, but they possessed pores along the arms at the sides of
the covering pieces, which may have served respiratory purposes.

Most of the IchthyocrinidsB have interbrachial plates, which in some
species are large and massive, in others small ; and some are regularly
arranged, others irregularly. The mouth is opened out, the ambulacra are
tegminal, and rest in an integument of very small, ill-formed pieces,* which
extend to t!ie ir>,erradial plates in the cup, and those at the sides of the
brachial appendages. The small plates form pouches or sacs, which some-
times reach to the second or third bifurcation. The median lines of these
pouches are occupied by the ambulacra, which converge to the mouth, sepa-
rating the orals.

Here we have among Palaeozoic Crinoids a tegmcn, which has all the
characteristics of the disk of living species, down to an uncovered mouth and
open food grooves, thus demonstrating conclusively that the disk as a ventral
structure is not confined to the Neocrinoidea. The discovery cf this fact led
to entirely new ideas touching the derivation of these groups. Before, it
had been supposed that the " vault " ceased to exist in Neozoic times, or was
reduced to the orals. It may now, we feel assured, be considered as estab-
lished that the structure of the tegmen in the oldest Palfeozoic Crinoids,

• We carefully removod the nrins in scvprnl well pirsrrved specinieiis of Oiiycliopriiiiis Ulriehi mid
0. (liversiif, niid in several instances fonnd portions of the ventral disk imbedded in the dorsal eup, lying upon
the inner Hoor of the plates. The disk of these ajiecies must have been extremely pliable, and probably con-
sisted iu part of soft tissues.

124

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

1 U

I :

although the mouth in most of tliem remained closed throughout life, was
not morphologically distinct from that of the Crinoids of existing forms, and
that the so-called " vault " has been developed gradually from the disk.
The Camerata, therefore, cannot be the progenitors of recent Crinoids ; they
represent a side group, which in the course of Palasozoic time departed
essentially from the primitive type, reaching the culmination of extravagance
in form and size in the Carboniferous, and becoming extinct at the close
of tiiat epoch.

B. T/ic Ami Plates and the Anus.

The Anal plates bear a most important part in the phylogeny of Palaeo-
zoic Crinoids, and are also of high importance in respect to classification.
Some writers apply the term " anal plates" indiscriminately to all interradial
plates of the posterior area, while others restrict it to the plates directly or
indirectly connected with the anus. We apply the term to the latter plates,
but only to such of them as take part in the dorsal cup ; the others being
plates of the anal tube or ventral sac.

The anal plates in all Camerata, when present, occupy the median line of
the posterior area, so as to divide the interbrachial plates into two equal
sets ; and in rows containing an odd number they have the effect, as it were,
of breaking up the middle plate into two, even in cases where no anal plate
is inserted between the segments. The latter is the case in the Actino-
crinida?, in which the first interbrachial row at the posterior side always
consists of two plates, in place of one as in each of the others ; though all
have an anal plate between the radials, and an extra plate in the second
interbrachial row. In the Batocrinida? and Tln'sanocrinidas there are two
interbrachial pieces above the first anal, which enclose a second anal piece.
The Hexacrinidae have but one large anal plate resting upon the basals.
The Eucalyptocrinida) have no anal plate at all, the five interbrachial areas
being perfectly symmetrical. Such is the case also in Dolatocrimis, Stereo-
crinus, Centrocrbius, AUocrimis, and PatelUocrinus ; while the typical Melo-
crinidae have an anal plate in one or more of the upper rows. Similar
variations occur a-^^ong the Rhodocrinidae, in which anal plates may be
either present or absent. The Platycrinidae have no special anal piece, but
the middle plate of the proximal row at the posterior aide is considerably
enlarged, and evidently united the functions of an anal plate with those of
the regular interradial.

■> *

MORI'HOLOGICAL PART.

125

It tliiia appears that the anal plates vary consitlerably in their position
and distribution, and in some groups are absent altogether. As a general
rule, they are largely represented in species with a strong tube, or a protrud-
ing lateral opening; while in forms in which the anus is central, as in the
Eucalyptocrinidic, or comparatively small, they are either wanting or but
feebly represented. The anus, although more or less influencing the whole
posterior area, did not necessarily require the introduction of anal plates,
and when the tube was small, an enlargement of the regular interbrachinl
plate sufficiently increased the width of the area. The anal plates, therefore,
do not appear to constitute an essential element of the Crinoids, but seem
to be supplementary pieces, introduced when the space was insufficient to
accommodate the tube.

Among the Fistulata, the term "anal plates" has been npplicd to two
plates of different origin, the one radial, and the other interradial. Tiie
latter is the hoinologue of the " special " or " first" anal plate of the Came-
rata, and rests upon the truncated posterior basal. When there are two
plates in the species, as in most of the Poteriocrinida?, and occasionally in
other families, the second — which is actually the first or lowest in point
of position — is located obliquely to the right of the first, so as to encroach
more or less upon the proximal face of the right posterior radial. Its lower
angle rests upon the upper sloping faces of the adjoining basal, its upper
face supporting the first plate of the tube, which in some of these genera is
partly enclosed in the calyx. To understand the position of the lower plate.
it should be noted that throughout the modifications which took place in
tlie posterior interradius in geological time, this plate always retained its
alternate arrangement with the basals, and occupied a radial position from
the beginning. Its form was changed, and to some extent its relation to
surrounding plates, by the increasing width of the ventral sac, which caused
a displacement of the nrm-bcaring plates. The oblique position which the
plate holds toward the posterior basal and the regular anal plate, and the
latter toward the first plate of the tube, gives to these pieces a sort of
alternate arrangement, which is continued throughout the tube.

The changes that took place among the anal plates in the various groups
of the Fistulata have been discussed by us at different times,* from which it
appears our views have undergone considerable modification as the result of

• 1879, Revisinn, Part I., pp. 71 nnd 72; 18S.S, Amer. Joiirn. Sci., Vol. XXVI., pp. 365 to 377; 1885,
Rev. Pt. Ill,, Sect. I., pp. 11, 12, 40; and 1886, ibid.. Sect. II., pp. 196 and 210.

126

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

further research. The .subject wa.s also discussed by Dr. P. H. Carpenter In
his paper " On the Kehvtions of Ilijhocrimis, Baerocrinua and Hi/boci/tititcs,*
and lately by Mr. F. A. Bather in a paper " On the Briti.«h Fossil Crinoids."t
Bather agrees with us and with Carpenter that the radially disposed plate
is a posterior inferradial, which in some groups took on anal functions.
He gave it the name " radianal," which we have accej)ted, but we
apply the term only when the plate actually serves as a support of the
tube. Ro.<»pecting the origin of the other plate, which we take to be a
special interradial, he advances views from which we regret to be obliged
to di.ssent. His idea is that this plate " originated as a plate morphologically
corresponding to an ordinary brachial," and lie undertakes to prove that in
its paliuontological development it pa.ssed down from above the radials to the
basals, and between the radials. He calls it a " brachianal," — a term which
becomes meaningless if it proves to be interradially disposed. To this plate
we apply the general term " anal plate," as we take it to be the homologue
of the anal plate of the Antcdon larva, and structurally identical with the
first anal plate of Actinocrbius.

We give, on Table C, a series of diagrams to illustrate the development
of the anal plates, in which the "brachianal" — of Bather — is marked x.
The radials are designated by the letter R, and when compound, the lower
section — the inferradial, which is also the "radianal" when it helps to
support the tube — by R. The tube plates are called t.

To the Plate R we have already alluded in the chapter on the radials,
discussing those forms in which it represents a part of the radial, and lies
in a vertical line with R. Let us now consi<ler tliose forms in which it serves
as anal plate. Among these forms, of which rokriocriiuts may be regarded
as the type, four of the five radials are simple, and the Plate .r, which is gen-
erally represented, rests upon the basals. The ventral sac, which in the ear-
lier forms was rather insignificant, had rapidly increased in si/e at the close
of the lower Silurian, in such a manner that the sloping upper faces of the
radials were insufficient to support it, and certain cltanges in the structure of
the dorsal cup became inevitable. It thus happened that the two posterior
radials, which had previously been in contact laterally (locriiiKs, Fig. 9) were
now parted, and the Plate .r was introduced to fill the vacant space (Dcn-
(Irocrinus, Fig. 13). The.se modifications, however, did not afTect the position

I \

* Quart. Journ. Geol. Soo. London, Vol. XXXVIII., pp. 298-312.

t Ann. ami Mag. Nat. Hist. (Gth Scr.), Vol. V., April, 1890, pp. 319 to 331.

\ !

\ \

i '

^ ^

f'\ii

MORPHOLOGICAL PART.

of the inferradiiil, which retained Its place between the npper sloping faces
of two basals, only changing its outlines to conform to the shape of, and fit
in between, adjoining plates. In the Carboniferous, in which the ventral sac
attained its greatest dimensions, and the lower faces of the costals frequently
fill up the whole width of the radials, leaving no space upon their distal faces
for an attachment of the tube, the superradial, Ji, was shifted to the right,
into a position almost directly above the right postero-lateral basal, and
obliquely against the inferradial Ji' {Poteriocrinm, Fig. 2). Finally toward
the close of the Carboniferous, when the tube was reduced to its primitive
insignificance, the anal plates gradually disappeared, and the five radials re-
sumed their normal position as in Erisocrimts, Stcmmatocrimts, and Encrinuii.
This is entirely different from the interpretation of Mr. Bather, who
reaches the conclusion that the anal plate x was primitively derived from a
brachial, and that in geological time it passed down from above into the
dorsal cup. He regards (oj). cit, p. 329) " tho.se forms as primitive in wliicli
the radianal is more of a radial and less of an anal, in which it is not in an
asymmetrical position but corresponds to the other lower brachial plates.
Such forms are locrinns, Ileterocrimts , Eetenocrinus, Anomalocrbms, and J\[a'n-
crinus. Now in all these forms x- is supported by 2i, and does not touch I\".
Obviously then x is not derived from JI', but originates above Ji, and on its
left side. By parity of reasonmg we assume the next stage to be repre-
sented in such forms ns JFi/bocrimis (I), Ottaivacr inns, Dendrocr inns, and Ilomo-
crinus, since in them R is rather more asymmetrical. In these .r has
passed down from .ibove R, and now rests with its lower half between the
right and left posterior radials, being supported partly by Ji' and partly by
the basal. Carahocrinus, Boiri/ocrinus, and similar forms are, as all acknowl-
edge, the next stages in the shifting of the radianal ; in these z has sunk
still lower into the dorsal cup, and is now entirely in a line with the radials.
... In Purisocrinus and Euspirocrinus among pinnuless forms, and in the
Poteriocrinites, another change has taken place ; the radianal has passed
through a revolution of 90°, and the lowest plate of the ventral sac {t) has
sunk down between R and .r."

Before inquiring into the validity of this argument, it will be well to ascer-
tain whether the plates of the different genera which Bather calls x are
structurally the same thing, for an error in this respect would be fatal to the
whole theory. The question is, is his plate x in locrimis and J\fcrorrii)iis,
which rests upon the one marked by him B or C, and that resting upon R

s J ;«

128

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

■P^ I i'

ii'

if it
I ■

in Ilijhocrinus, and R in Anomalocrinus, homologouH with the plato of Den-
drocriniis, Hmnocrinuti, etc., wiiicli is supported by K and partly by the
biisals, and also with the plate of Poteriocriitiis, which re.sts upon the basals
and against the radianal Ii' ? This question was not discussed by Bather,
though we had expressed views different IVoin his respecting the plate x in
lutrinits and Jliwcrinua. That plate was regarded by us, in both genera (in
locrimis as early as 1879),* as a plate of the tube, and, so far as we know,
we never made any statement from which he might infer that we thought it
represented the plate x ; yet he quotes us ii> his diagram? as if we had done
HO in 1879.

Instead of commencing with the earliest forms, as Bather did, we begin
with the simplest, and select as a starting point the genus Ci/athocrinus, which
is so well known to every paUvontologist. Ci/cit/iocrinxs has simple radials,
and but one anal plate, which, as all writers agree, represents the plate x. It
rests upon tlie truncated upper face of the posterior basal, between two ra-
dials, and is generally followed by three plates of the tube (Fig. 3), of which,
as in the Butocrinida), the two at the sides rest to an equal extent against
— or rather upon — the sloping upper faces of adjoining radials. The
structure of G'raphiocriniis de Kon. and Le Hon, as amended by us in 1879, is
similar to that of Ci/afhorrinits. This genus also has only the plate a; repre-
sented, but here it is angular at the upper end instead of truncated, and
supports but two e(|ual plates of the tube. This produces a sort of bilateral
.symmetry in the posterior side of the tube, each plate supporting a vertical
row of hexagonal or subquadrangular pieces.

Next in order we take DcndrorrinuH, in which the right posterior radial
is compound, and its two plates are in line vertically. This genus is an
intermediate form between the earlier and later Fistulata, and its struc-
ture throws important light upon the phylogeny of the group, especially
as to the anal plates. Contrary to the rule in most of the earlier Fistulata,
the plate x is well represented, but the inferradi.il, R, is not in a position to
perforin anal functions.

Let us examine the form represented by Dcndrocrinus Casei, from the
Loner Silurian of America (Fig. 18), a species with rather narrow, horse-
shoe shaped radial facets, and an extremely large ventral sac. The two
posterior radials are widely separated, and the plate x is succeeded, as in
Cyathocrinns, by three plate.s, t, t, t, of which the middle one rests upon the

Revision, Pt. 1., p. 05.

MORPHOLOGICAL PART.

129

triincixte upper face of plate x. The pliite to the right lies at a soinowhnt
higher level than the one to the left, anil does not toiicli ,r, owing to the
greater length of the conipounil radial, while that to the left toiicheH it
slightly. The three plate.s form part of the free tube, and eaeh one is fol-
lowed by a vertieal row of other tube plates.

Comparing this strueture with that of Iltttrorr'mus (Fig. 10), Evtmocrbnts
(Fig. 11), and Ifybocrliuin (Fig. 8), we find tiiat tlio plate t in all these forms
takes practically the place of the tiirce plates (ttt) in Ikitilriirr'nutn. In
either case the plates constitute the lower tube plates, and rest — the one
as well as the three — upon the sloping upper faces of the two posterior
radials; but while the three plates of jDt'Hf//'ocr»u<s ore supported by a special
anal plate, the radials of Ifrfirocrinus, etc., meet underneath, and the anal is
unrepresented. In Dcndrorrhms, which has an extremely large anal tube,
the anal x is well represented ; while in the three other genera, in which the
tube is narrow, and the outer edges of the radials are sufficient to support
it, that plate is wanting. If it were true that the plate t in Jlctcrocriinis
represents the plate x; and sunk down in palafozojc times to the basals, as
supposed by Bather, the plate x would be represented twice in Dcndrocriniis
Casci, once by x, and again by f, both plates being present and in place.

Bather makes the statement (p. 331) that the " brachianal " and the
plates succeeding it in regular series, are to be regarded as brachials, but
that the remaining plates of the sac are nothing more than plates deposited
in an extension of the ventral perisome, and in conformity with this he
has called the superradial of locrinits an axillary plate. The term " axillary "
in Crinoid terminology is given exclusively to jilates of the ra3's, and every
axillary is followed necessarily by a branching of the arm. Bather in using
that term must have supposed that the so-called brachianal, and the plates
succeeding it, are parts of a modified arm, which in geological time became
incorporated into the sac, for in no other way could we understand why lie
called it an axillary. He has probably been misled by the angularity which
occurs upon the upper face of the superradial, or by the form of the plates
succeeding it to the left, and the slanting position of the posterior arm to the
right. In that case he overlooked that the radials in Adinocrinns also have
sloping upper faces, and yet that those plates are not axillaries, supporting
as they do at one side a costal, but an interbrachial at the opposite side ;
and it did not occur to him that such might be the case also in Jocrimis.
Examining the anal interradius as it appears in the Camerata among the

130

TlIK CHINOIDKA CAMKRATA OF NORTH AMKRICA.

Vftrioiis familii'fl, we find in tlio Biitociinitliv) directly above the plute a; a
Huppleiiifiitiiry mud, mid an interbrachial at cat-li wide of it, exactly as in
most tpccies of Cyuthovrinus and DeiidrDcrhuia, except that the interbrachials
of the two latter — /'. c, the plates corresponding to them — are incorporated
into tho tube, but those of the Batocrinidoo into the cup. Turning to the
Actinocrinidie, the plate ,c supports a supplementary anal in the second inter-
brachial row, but none in the first, a structure recurring in Gni/iliiocriniis,
in which a; is followed by two tube plates which take the place of the two
interbrachials of Actinocrinus. In the Dolatocrinites, however, in which x is
wanting, and the first row of the anid interradius is formed of n single plate,
this rests upon the sloping faces of two radials, tins occupying almost the
same position as the plate / {:v of Bather) in Edcnocrinus, Ili/hocrinufi, and
lucrinus. That the plate t in some of these forms is somewhat irregular in
position, leaning more to the right than to the left, is due to the asymmetry
of the right posterior radial.

From these observations it appears that there is a close agreement be-
tween the anal i)late and tube plates of the Fistulata on one side, and the
anal plate and interbrachials in the cup of the Camerata on the other; and
we are led to believe that those plates respectively are homologous. Admit-
ting this, wo have a much more satisfactory explanation of the anal plates of
the Fistulata than that given by Bather, whose views are totally at variance
with the structure of the Camerata, and are based upon premises which are,
to say the least, hypothetical.

After agreeing upon the structure of Dendrocrimts and locrimts, that of
the other Fistulata is readily understood. Ammcdocrinus is in a condition
similar to that of locrinus, but it has two compound radials instead of one
(Fig. 12). The plate x is unrepresented, and the tube, which is narrow,
rests within a notch formed by the sloping upper faces of the two posterior
radials. Nearly the same structure is found in Heterocrimis and Edenocrbnts
with thi-ee compound radials, and in ILjhocrinus with but one, and in all of
them the plate a; is wanting. IIo»v Mr. Bather could conclude from the
structure of Edenocrimts, locrimts or nyhocrimis, three of the most primitive
forms, that x originated as a plate "■ morphologically correspomling to an
ordinary brachial," and that t could sink down to the basals, we do not
understand. It appears from his own diagram that the plate which he calls
X in Edenocrinus is placed symmetrically between the two posterior radials,
resting as much on the one plate as on the other, but not touching the basals.

QQQTa

mm^

MORPnOLO(iI( Al. PART.

TABLE C.

131

D^fe^

1S| oTo^ol^

^^ci»2>c%o.o

^S^^

DIAGli.VMS ILLUSTRATING THE CHANGKS IN TIIK DEVELOPMKNT OE THE ANAL

SIDE IN THE INADLNATA.

1. lon-imi.i si(brra.i.iiis ; 2. Pu/morriiiiis ; 3. Ci/allmTimis ; 4 Pisorriiiiis ; 5 Ildphi-riiim rlio ; fi. St/m.
bathocniiiis ; 7. linerorriiiin ; H. N^//ocriiiii.i ; i). loi-riiiiix ; 10. Helcrorriniis helli'villciisii ; 11. Erlrnocriiius ;
12. Aiiowaloniniis ; \X noiiiocriiim ; U. Dendroerinus ; \o. Poterioeriiiiis ; 16. Crriocriiiiis ; 17. Ulocrinut ;
18. Erisoeriiim ; 19. Alliigecimin.
* = bnsal3; « = ra(liiils; /f' = iiiferrailinl; .r = special nnnl plate ; /=costals; / = tiibopktes ; o=orals.

132

TIIK CHINOIDKA ( AMKIIATA OK NOKTII AMKKICA.

Seo mir diagriiiM (Fig. 11). So nl.so (Iio pliitc / of Ifctrrocriiiits hclltrillcHsis
(Fig. 10), llioiijfli loMH syimnotriciilly (li.><|i().soil, whU inmii Liolli ruUiul!*, iiiitl
nut on tliu pliitu tu the right only, nn (igiirud hy Hiitlu-r.

Wo now pii.ss to tlioso forms in wliicli the inrcrmdiiil II' pcrfoniiH the
function.'* of an iinul plate. The first stop in this direction it* nhown by
Ilonincrlinis (V\g. 14), lliifri/dcriiiii.i, Oncocriiiiis, iind liitnjrrlnuH, in whicli (lie
Huperriidial A' ha.s siiifted .slightly to the light, and it* connected with the
inferriidiivl hy an oblique sutiu-e ; contrary to the caHO of I)cii)lrocriiius,
in which the two plates are arranged vertically (Fig. 13). The plate t in
tho.so forms rests upon R without touching If, and the plato x, which is
comparatively largo, rests against botli sections of the compound radial.

Bather explains the evolution that took place in these forms by " the
shifting of the radianal," and that "./• has sunk still lower into the dorsal
cup, and is now on a line with the radials." Nothing of this kind is indicated
by the specimens, which clearly show that tlio radianal throughout the
Fistulata retains the same position, whether it constitutes a part of the radial
or .serves as anal plate. It oidy changes its outlines so as to conform to the
shape of contiguous plates. As the tube became larger, the radinis spread
out, and the vacant space thus formed was filled by a new plate, a;. There
was no sinking of the plate t, which never moved from its place above the
radials.

Another stage in the developmental history of the anal area among the
Fistulata is presented by P(irlsorriaiin, Atchstorriniis. EuKpirocrinuH, and the
typical PoteriocriniiliB. Bather, in alluding to them, makes the following
statement: " In the Poteriocrinites (see our diagram Fig. 2) another change
has taken place; the radianal has passed through a revolution of 90°, and the
lowest plate of the ventral .sac {t) has sunk down between R and .r." If we
understand what this means, he assumes that the lower section of the radial
moved to the left ; while in fact, as the specimens show, it was the upper
section of the plate that moved away, shifting to the right and leaving
a space for R' and t to meet. Thus it was that x came to rest against R',
but not against 7?, from which it was separated by the plate /. An increase
of width in the anal area became necessary, as the surface for the support of
the tube was insufficient to hold it. In Homocrinus and Dendrocrimis, the
costals occupy only a comparatively small part of the radial, and a rather
large portion of the latter serves as a support for the tube. In the Poterio-
crinidae, however, and in Parisocrinus, Enspirocrinus, and Atelestocnnus, in

MOKI'IIOLOdlfAL I'AUT.

133

which thu hracliiiilH fill up tliu giviiter imrt, ur nil of tliu diMlul luci* uf the
nidiiilH, It I'utiuii'fd udditiutitil HuifucuH for thu iiccomiuudutioii ut' the laigi'
tiihe.

From the stnictiiro of the typiciil Potoriocriiiidro w« coinp to thnt of
Vliirriiiiin, (I'rdjiltiiiiriiiiis, C'lriiirriiiiis, Krisurrlims, uml StinDiiuturriiuis, wliicii
wo rej^iii'd a^ tniiHilioii I'oinis toward h'urrliuis. 'I'lio vt'iilral tula', which in
the latter of thoHu foriiiH dwindled to a Hliort cone, did not roqtiire ns largo ii
Hnpport in the dornal cnp, iind nH the nnal p'litCH gradually hecaine oh.xolote,
tho posterior radiaN resumed u Hymmetriial form. In Ulocriniis {V\\^. 17)
the plate x was crowded out by the large nidinnal ; while in Oia/i/iiocrimis
and Ccn'iicrliiiis (Fig. 10) only tho former ix ro[trcsented. In (Iriipliincriitiis,
with a wide ventral Mac, tho anal plate ih large; in Ccn'ocrintis it is reduced
to a small piece, and the posterior bnsal is con.siilerahly elongated. JCrisit-
ci'iiws (¥\g. 18), S/fiiiiiKiiocfinus, and Eiicrintis have no anal plates at all. the
cup being perfectly synnnotrical ; and the tube rests entirely upon the
edges of the radials, whence it started in Hi/f'nrrimm, Eclcuocriiius, and
allied forms.

In view of these facts, it see.ns lo us that Bather's theory of a " brachi-
anal" is based upon a wrong interpretation of some of tho plates. If it
were true that tho plato of Incriniis to the left of the supraradial passed
down in later forms to the basals, it would mean nothing less than a partial
revolution of tho entire tube. This, however, is dispioved by the structure iis
well as tho palaeoutological development of the tube, which latter is genendly
composed of lon;jitudinal rows of hc.vangular pieces, alternating in adjoining
rows. In the earlier and simpler forms tho tube consists of only five series,
one to each intorradius, that of tho nnal side resting upon plate /. Later on,
as tho tube grew larger, a now row of plates was introduced with plate .<• sup-
porting it. When there are three series, as in Detxhnrrhnis, the third genendly
rests upon one side of tho left posterior radial. The arrangement of the
plates within tho rows is .so regular that if a sinking of the plate t bad taken
place, it would certainly be indicated by some disturbance among the lower
plates in the tube. In species where tho tube has more than three rows, one
or more of tho primar}' rows dichotomize at some distance from the cup.
The fact that the increase of the tube pliylogenetically took place by the
introduction of new rows of plates, is a strong argument in favor of our idea
that the plate x is also a supplementary piece, and was introduced in the
same manner as the plates which it supports.

' >|i

134

THE CRIXOIDKA CAMERATA OF NOUTII AMERICA.

The syininetry of the Ciii oitls, as a rule, is bilateral, and the nnal area
occupies the median axis. The usyniniotry which occurs in many Fistulata,
and in certain Ichthyocrinidiu, is caused by irregularities in the radials.
Wherever tiiese attain a regular form, the plate x takes its median position,
and the plates ol' tiie ventral tube are arranged on a strictly bilateral plan.

Wiiether the symmetrical calyx, as represented in the Silurian and later
Cyatliocrinidic, was evolved from the asynnnetrical form, we are unable to
ascertain. It may be that tiie two had a common synnnetrical ancestor, or
tliat ail these Crinoids were primitively asynnnetrical, and that the lower
section of the posterior radial became early resorbed in some cases. Against
the former theory it may be said that in the Lower Silurian Fistulata, so far
as we know without exception, the right posterior nidial is compound, and
that the synnnetrical form occurs with the other in the same families; against
the latter, that the symmetrical form is already well represented in the
Upper Silurian.

We have made no reference here to the Calccocrinidro and Catillocrinidoe,
as we have not at present the material to study the older forms; but we feel
quite certain that their structure in this respect shows no material departure
from that of the older Fistulata.

The anus of the Crinoids is located in the disk, and is either central, sub-
central, or marginal, — in the latter case .sometimes coming down to the
arm region. In some species there is merely a simple opening passing out
directly through the disk ; others have a tul)e with an opening at the distal
end or along the side. Tlie size of the tube is quite variable. In some
genera it rises to a height of several inches beyond the arms ; while in
others it is less tlian half their length. The tube is compo.sed of heavy,
generally nodose, wedgeform pieces, admitting but little mobility in the
structure. When there is no tube, the amis is generally situated within the
centre of a wart-like intlation, composed of very minute pieces, which
possibly were movable, and could be drawn in by the animal, like those
in the " probo.scis" of recent Crinoids, so as to open or close the aperture.

Tliere has been some difference of opinion whether or not species with
an anal tube should be separated generically from those with a simple
opening. Considering the slight differences upon Avhicli many genera have
been founded, it would seem that the tubular structure ought to be of
sufficient importance to justif^v a separation : but considering that various
groups, after being carefully restricted with reference to all other characters,

MORPHOLOGICAL PART.

13o

include both forms, its viilue as a full generic cliaractor might well be
doubted. It was probably this that led Meek and Worthen to establish
subgenera for these forms. We finally concluded to make them full genera,
finding considerable objection among naturalists to subgeneric divisions.
Only in Flatycrinus and Mdocriims were we obliged to retain both forms
under the same generic name, as we are unable to separate them. Their
tegmens are rarely preserved, and among the species of Platijcrmus espe-
cially are found all possible gradations from a simple opening to a good
sized tube.

As a rule, a tube occurs more frequently among species in which the
arms form a continuous series around tiie calyx; while species in which they
are arranged in clusters often have a simple opening. Most of the latter
forms have a wide, more or less depressed space along tiie disk, between the
two posterior rays, for the foecal matter to pass out; but when the tube is
long, and the arms in close contact all around, the excretions were dis-
charged above the arms.

Occasionally, among species with a slender tube, we find specimens in
which during the life of tiie animal the tube was broken at the base, and
the fractured edges upon the disk were rounded off by calcareous growth,
so that it appears like a simple opening. From this we ooiiclude that the
tube had no important bearing upon the general organization of the animal,
and that tlie Crinoid could live without it. This is also indicated by speci-
mens in which the anal tube was obstructed, and a new passage formed
at another place. Abnormal passages of this kind occur along the tube,
upon the disk, within the dorsal cup, and even within the basal ring.
They are more or less restricted to the posterior side, but are not neces-
sarily in a vertical line with the anus, as wc formerly supposed. When
it occurs within the basal ring, the opening is located anteriorly, but
turns to the right whenever it enters the sides of the dorsal cup. It is
located posteriorly — or nearly .so — close to the arm bases, but above the
calyx it may occur on any side of the tube. The Museum of Comparative
Zoology has a very interesting specimen of Bniocrimis lonr/irosiris, in which
a new tube of the same size as the original one has been formed just
above the calyx. In this instance apparentU' the second tube also became
obstructed, and a third one was in process of formation. A similar casi- is
presented by our specimen of Bntocrhum hmra (Plate IV., Fig. 14). The
tube in the specimen of Eiitrochocrinus Christi/i (Plate IV., Fig, 10) gives off

■ [i

136

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

a small branch horizontally at a short distance from the disk. In another
specimen of that species (Plate IV. Fig. 17), in which the tube is broken above
the arms, it was replaced by another, which starts off !*oiaewhat obliquely
from the top of the stump. A tube in a similar condition was observed in
a specinu'U of Lobocrinus 2))jr)furmis, but there tiie recuperation made but
little progress, for the new part did not attain one third the width of the
old tube at the point of fracture. In the specimen of Macrocrinus jticundus
(Plate IV. Fig. 15), a small branch .starts from the tube close to the calyx,
while in another specimen of our collection a braneiilet is given off near the
end of the tube. In Fig. 12 of the same plate (Steijanocnmts pentagomis),
and in Fig. 11 {Teleiocrinus unihrosus) a second tube was formed at the top
of the disk, iu the former occupying the median line of the posterior area,
and in the latter directed .sliglitly to the right. In the remarkable specimen
oi Etifrochocrimis Christi/i (Vhxte IV. Fig. 13) all the arms of the right pos-
terior ray, and the outer arm of both adjoining rays, were destroyed, and the
break in the test was closed by irregular new {/.ates, which support a con-
spicuous second tube. A still more remarkable instance of recuperation is
presented by a specimen of Batocnmtn stthwqitaHs (Plate IV. Fig. 10), in which
an enormous tube breaks forth above the basals. It occupies the whole
length of the dorsal cup, and involves the plates of the posterior interradius,
as well as of the posterior ray, and even some of the arm openings. The
plates bulge outward almost at right angles to the sides of the cup, and form
tiiu lower part of tlio tube. Fig. 9 has a very large opening between the
basals leaning somewhat toward the anterior side, which we think performed
the functions of the anus in that specimen.

Passing now to the Inadunata Larviformia, it must be stated that, so far
as observed, the anal x is unrepresented throughout this group (.see Figs. 4,
5, 6, and 19 of the preceding diagrams), nnd we know of no case in which the
anal tube, where it exists, is supported by an iuferradial. This is explained
by the absence of interbraohial and intcrambulaor.il plates, and the position
of the anus intermediate between the radials and orals, or piercing the latter.
risocrinus* Phimocrinus, and Symbathocrimts have a long slender tube be-

• The tube of Pitorrimit wns observed by Bntlier, niid described by him in liis late work on "The
Oriiioidca of Gollnnd," Part I. p. 22). Tt rests upon the triiiieatcd limbs of the eompoinid mdial and the
large simple one to the left ; hut not upon the t\ro supported by the plate R'. Halher refers the proximal
plate of the tube to the nnnl .r, allhoui;h the plate rests, like / in Kr/riioi-n«uf and ffy/jofiimif, upon the
radials, anil lakes no part in tlie eompnsilion of the eup. So also tlie eorrcsponding plate in Symhathocriimi
is a tube plate, and not an anal as we stated in our earlier writings.

MORPHOLOGICAL PART.

137

I I

tween the arms to their full length, which in Si/nibathocnmis is composed of
elongate quadrangular pieces. The tube rests upon the upper faces of the
posterior radials, and extends to the tips of the arms. ILqdocrbms, as we
understand it, has a simple anal opening, piercing the upper half of the
posterior oral. Ciipressovrimts has a well-defined aperture between the
muscle plates of two adjoining radials.

The anus of the Inadunata Fistulata has been observed in but a few
instances, and then only in the CjiUliocrinida!, the Poteriocrinidaj, and in
the embryonic Ilijhocrinus and Carabucrlniis, In all of these cases, the open-
ing was apparently covered by a rather large, rounded pyramid of eight or
more pieces, which reseiiibles the anal pyramid in the Cystids. In Caraho-
crimcs, in which the ventral disk remains permanently in the larval state,

( i'

Fio. 1.

Fig. 2.

Carabocriiiiis. — Fig. 1. Ventral Hspect. Fig. 2. Dorsal aspect.

R = rnilinls ; IV = nuliaiiiil ; x = anal ; rp = nnal pyramid ; o = orals.

having five large orals similar to those of the Larviformia, and snbtegminal
ambulacra, the pyramid is excentric and directed upwards (Figs. 1 and 2 of
the accompanying diagrams).* A similar anus was observed by W. R. Billings
in Hyhocrimis conicus. In Cyathocrimis wo have observed the anal pyramid
in several species, and found it located in all of them at the end of tlie tube,
directed anteriorly (Plate VII. Figs. 11 <ih rnd \2(if/). The anus of the Pote-
riocrinidoB, which we havf; seen in Poteriocrinu.t, Decadncrinns, and in several
species of Sei/talocrimis and Scrq^hiocrinus, is located at some distance from
the top of the ventral sac, and invariably at the anterior side, sometimes

• These diagrams were made after drawings hy Mr. Waller R. Billings. The specimen of Fig. 1 is in
the collection of Mr. J. Stewart, that of Fig. 2 in his own collection.

138

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

very low down in the sac (Plate VII. Fij^. la). An nnitl pyramid has never
been fomul in place in this family, but that it existed, at k-a.st in some of the
species, seems very probable from the form and large size of the opening
(Plate VII. Figs. 1 a, 2a, h, 3, 4, 7, 8). There are other Poteriocrinidio, and
espL>cially among .species with an inllated, balloon-shaped sac, which have no
openings in the sac, and we are inclined to suppose that in these cases, and
also in many other Fistulata, the anus was located in the di.sk proper between
the sac and tlic mouth. In the remarkable AuIocrii)Hs represented on Plate
VII. Fig. 9, there is a large spout-like tube passing out from the huge sac
between the arms on the anterior side, half way down, like the simple
opening in Figs. 7 and 8. We have found this extraordinary tube pre-
served in five other specimens of this species, and its form and position
are very constant.

The anus of the IchthyocrinidaB has been observed only in Taxocrinus and
OnycJwcrimis {Forbesiocriiius de Kon. andLe Hon). Both genera have a small
tube, of which the posterior side consists of a vertical row of subcjuadran-
gular, comparatively large plates. I*s anterior side is composed of a large
number of very minute pieces, forming a kind of pouch, widest at the
proximal end, which gradually pas.ses into the di.sk. At the anterior side
the tube leans considerably to the right, and it may be suggested from this
that Taxocrimis ami Onychocrhms are derived from the asynunetrical Gnori-
mocrinus, whicii apparently had a similar tube. The arrangement of the
anal plates in the Iciitliyocrinida! is substantially the same as in the Fistu-
lata. In some of their genera only the plate ,t is represented, in others IV ;
while still others have no anal plate at all. Bather makes no rei'erencc to
the anal plates of the Ichthyocrinidoo, but regards tiie anals of the Camerata
as morphologically distinct from those of the Fistulata. On ]iago 31i)
{op. cit.) he says: "it may be pointed out that, as interradials do not
enter into the composition of the dorsal cup in an^^ Fistulata, none of
these plates can well be the homolognes of interradials : in many of the
Camerata actual interradials ai'e present in the anal area, b>it in the Fis-
tulata at least we must look elsewhere for tlie origin of the so-called
' anal ' plates." Now if it is true that the anals of the Camerata re-
present something different from those of the Fistulata, because the}'
possess no interbrachials, it must be the same also with the anals of the
IchthyocrinidaB, among whicii interbrachials are represented. But what
would be the result? Some of their genera have interbrachial plates, and

MORPHOLOGICAL PART.

139

others not. In Ljcannrrlnus IJilliiujsi* tliere is iit the posterior side an niiiil
a;, togetlior with a rudiaiial ; while at tiie other four sides the radials and
costals of a<ljoining rays meet hitcrally. Lccanocrinus macropdulus Angelin
(not nall),t on tiie other hand, with exactly the same arrangement of anal
plates, has a large interbrachial plate at the four regular sides. The case is
even more perplexing in Taxocrbnis Thicniei, of which some specimens have
one or three interbrachials, while others have none. We thus find within
the same genus, and even within the liuiitsof the same species, interbrachials
present or absent, and according to Bather's theory the anal plates of one
specimen would be homologous with the anals of the Fistulata, and those of
the other structurally distinct. He seems to have regarded the anal plate
in the larva of Anfedun as the homologue of the plate x in the Fistulata,
because the genus has no interbrachials. lie says: " it is not an interradial ;
for the so-called ' interiadials ' that some ob.servers claim to have seen are
only perisomic plates of no morphological importance ; further it is a most
gratuitou'< assuuiption to make Antedon the oidy form with an interradial in
the anal area, while devoid of true interradials in the otlier interradii." In
assuming that Antedon has no interradials, he employs the term in the
narrow sense in which it has been used heretofore ; but since then we liave
learned that all i)lates interposed between the rays and the ambulacra con-
stitute parts of the same element, and the same plates morphologically may
be interbrachial in one group, and partly or wholly interambulacral in
anotlier.

Thaumntocrinus is the only recent genns which lias a tube, such as we
find among the PalaBocrinoidea. This tube rests upon a large interradial
plate, which, however, is not a special annl, for a similar plate is interposed
between the radials of the other four sides, exactly as in the Rhodocrinidce.
This seems to us a further proof that the plate x is not a primary element,
but a supplementary plate, and was introduced only in cases where the
structure of the anus required it.

• Iconogr. Crin Suec, PI. XXIL Fig. 25.
t Ibid., PI. XIX. Fig. 4

ill

140

TIIK ClUXOIDEA CAMKRATA OF NORTH AMKRICA.

INTERNAL CAVITY OF THE CALYX.

A. Tlic Chambered Organ and the Axial Canals.

A striking feature in the organization of the Comatuloo is tiie quinquclo-
cular organ, situated in the cavity of the ceiitrodcrsal, and phiced at right
angles witli the central axis. Tiiis organ was first noticed by Ileusingor,
who in 1828 described it as the central organ of the blood vascular .system.
Mliller also took it to be a heart-like organ in connection with a system
of membranous tubes. Dr. W. IJ. Carpenter regarded the membranous
tubes of Mliller as solid fibrillar cords, proceeding from a similarly con-
stituted envelope around the chambered organ, and he came to the con-
clusion that this fibrillar sheath, and th> cords proceeding from it, constitute
the central nervous system of the Comatulu). This was afterwards confirmed
by experimental evidence, and is now generally admitted by zoiilogists.

The organ in question is a sac, divided into live radial compartments,
enclosed by a thick envelope in connection with the axial cords. From the
dorsal surface of this envelope processes are given off to the cirri, and from
its margin arise interradially five short primary cords, which, passing up-
wards and outwards, bifurcate into right and left branches between the
centrodorsal and radials. The ten secondary cords diverging from one
another, enter the substance of the radials, and either unite in pairs, the
right branch from one interradial meeting the left branch from the adjoining
one (Figs. 3 and 4), or the two branches, as in Enerinus Uliiformk (Fig. 5),
without touching each other, proceed on separately to the costals. On
reaching the first axillaries the two cords open out into two branches, right
and left, and after traversing the plates, enter the right and loft arms,
respectively. In addition to the above connections, there is a circular or
pentangular commissure, which, immediately after entering the radials, con-
nects the various branches among themselves, and additional connections
between the branches within the axillaries supply the arms (Figs. 3 to 4).
The axial cords along the arms lie in tubular channels piercing the calcareous
part of the various arm joints, each cord giving off alternately right and
left branches, which enter the pinnules.

Chambered organs have been observed also in Stalked Crinoids, but the
position is not quite the same as in the Comatulae. While in the latter the

MORPHOLOGICAL PART.

141

orfan is lodged within the centrodorsal, and is covered by the rosette,* it is
in rentacrinus, which has no centrodorsal, contained in a cavity formed by
the radiiils above and the basals below. The five chambers of Pentumnus
are not closed at the bottom, but are continued down the stem as five vessels,
systematically arranged around a central axis. These vessels were regarded

Fiii. 3,

Fig 4.

I
i

: I

Fig. 5.

Fig. 3, position of tlio axial cords in tlie yoniicr AiiMnii ronaeeiis (after W. B. Carpenter) ; Fig. 4,
their position in tlie atlult (after A. M. >[nrsliall) ; Fig. 5, in Eiirniim /iHi/ormh (after Beyricli).

ccl = centrodorsal ; i = infrabasals ; A = basals ; R = radials. Tlie dark lines show the arrangement
of the canals in tlie dorsal en p. '^

by Dr. P. II. Carpenter as homologous with the five openings around a single
one on the underside of the calyx, and along the stem of Ciipressncrinus, Myr-
tilocrinus, and Gasterocoma. Among recent Stalked Crinoids a chambered

• In most of the Comntulie, the embryonic basals are metamorphosed into the structure known as the
" rosette," which is enclosed within the radial pentagon, so as to be not visible externally.

142

rilE CRINOIDKA CAMERATA OF NORTH AMERICA.

;'S'

organ has been observed in lihizocrinitu, JJat/ii/criniis, nnd Jlulojnm, and it
existed probably in the other genera. Among Jurassiu and hiter fcssil
Crinoids, a.xial canals, piercing the body of the calyx plates, are known to
e.xist in the Apiocrinidco and Engeniacrinida) (Ilolopidie Jaekol), and tliey
are readily recognized in the Tria.ssic E)Krbms, in .some of the later Paia>o-
zoic Poteriocrinidiu, and in Mijcovrbius and Cafillocrinus ; but wc have found
no trace of them in the Camerata, except in Stajannciinus ])entagomis (Plate
LXI. Fig. 3), in which, so far as observed, the five or six proximal plates of
their tubular appendages are pierced by a canal. Such canals occur upon
the radials in some of the Cyathocrinida*. the CuprcssocrinidiD and Gastero-
comidiv, and we may suppose that a chambcretl organ existed in these and
other groups, if not in all Crinoids. In cases where grooves or canals for
the reception of cords are not apparent, the cords may have rested against
the inner wall of the plates.

B. T/ie Convoluted On/an.

In the abdominal cavity of Palajozoic Crinoids, the oidy organic structure
tiiat inider very favorable conditions has been observed, is a peculiar skeleton
which occupies the greater part of the cavity.

It is a large convoluted body, in its outlines resembling the shell of
a Bulla, open at both ends. Its upper part rests directly beneath the origin
of the ambulacra, tiie lower end within the baisal ring without touching the
plates. It is dilated above, contracted below, its lateral faces jdaced parallel
to the inner walls of the calyx; the bottom truncated. In some .species it is
subcylindrieal, with the vertical axis the longer, in others globose or even
depressed globose. In coiling around its axi.s, the partition walls do not
meet each other, but leave more or Ie.s.s wide interspaces. The convolutions
vary in numbtM' from 2 to 4 according to species, and are, as they pa.ss out-
ward, directed from right to left. The walls in the usual preservation are
thick, and perfectly .solid, as they were descril)ed by Hall; but in transverse
sections they froquentl}' appear as if compo.sed of two partitions closely fitted
together, and closed along the edges. In some specimens, however, the
walls are simple, and constructed of an extremely fine and delicate filigree
work, composed of minute pieces or bars, with intervening meshes, which
do not intersect at any uniform angle, but anastomose so as to impart a kind
of irregular regularity to the form and size of the meshes. No such structure
has ever been observed in the other specimens, in which the pores or meshes

MOHIMIOLOCI ICAL I'XHV.

14a

seem to have been obncuifd by hoiivy iiicrustiitioiiH of Milicious iimttir nt
both »iiiu.s, and thusu iticruatiUiuiiM iiiiiy hiivu piodiicud tliu aiipiueiit diipU-
cation of tijo walls (I'lato V. Figs. 1, 4, 'J, and 12).

Among tho many buautii'ul e.\ampk<s in tlio Wachsniiith collection at the
Miist'iiin of Comparative Zoology, in which tho convoluted organ is pre-
served, there are two uni(iue Kpecimens (I'iate V. Fig. 11 and Fig. 10); the
former showing the delicate porous texture, the other its position beneath
the anibulacral skeleton. The collection contains also the remarkable speci-
men of Mdcrocrimts vcrnextiUanus (Plato V. Fig. 8), in whicli the upper end
of the organ is surrounded l)y a large annular ve.s,sel with five radial and five
interradial openings. In this species tho end of the outer fold turns into
a narrow thickened strip, which ascends spirally toward a place in the
fli oiou of the anal tube. This structure differs somewhat from that of
'"etehcrinus and other genera which have a thickened edge along the lower
margin of the outer fold passing upward (Plate V. Figs. 1, 3, 12). In a
specimen in our collection, either of *S'/m<opW)(Hs or Tdelocrinus, we succeeded
in removing at one side the two outer folds, and exim.sed the third or inner
fold (Plate V. Fig. 4), which has the form of a spindle, thicker at the middle
and tapering to both ends. It seems that the innermost cavity in all caseo is
spindle-shaped, and that the inner end winds spirally upwards like a screw
with rather sharp, roughened edges, — the so-called "collar" of Meek and
Worthen. A connection with the aiidiuhicra has not been satisfactorily
observed in the specimens ; neither the upper j)art of the organ, nor the
ends of the and)ulacral tubes, have been found in perfect pro-ervation.

The function of the convoluted organ can only be conjectured, as no
similar structure has i oen observed in recent Crinoids ; but from its position
it seems probable that it was connected with, or formed a part of, the
digestive apparatus. If the latter was the case, the thickened outer end,
leading toward the anus, may represent the hind gut.

SYSTEMATIC PART.

A. Classijicittion.

Ix our classification of 1885,* under the belief that the Brachiato
Crinoids were divisible into two groups so widely dift'crent in their ventral
structure as to entitle tlieni to rank as distinct orders, we adopted the name
Pelmatozoa as a collective term to include I be Crinoids, Blastoids, and
Cystids. In so doing we followed the lead of Dr. P. II. Carpenter, who t
brought forward this name as one which had been introduced by Leuckart
in 1848 ; with the differeiice, however, that whereas Carpenter used it to
designate the Stalked Echinodcrins as a " branch" of the " pbyUun" Echino-
dermata, and to include the Crinoidea, IJIastoidoa, and Cystidea as classes of
equal rank, we proposed to treat the same collective group as a "class" of
the Ecbinoderinata. We subdivided the Pelmatozoa into two subclasses,
the first to contain the "orders" Cystidea and Blastoidea, the second the
Crinoidea. The latter we divided into PaliDocrinoidea and Neocrinoidea.

It has been shown by Agassiz % that the name Pelmatozoa, although used
by Leuckart at various times to includo the Cystids and Crinoids, — presum-
ably including in the latter Blastoids also, — can hardly be considered as
well established ; that it was not adopted by any writer on Crinoids before
Carpenter, except Sir Wyville Thomson, and that Leuckart himself, from
1848 to 1879, used Crinoidea or Pelmatozoa indiscriminately in the same
sense.

The term " Pehuatozoa," as having reference to the pedunculate condi-
tion, is objectionable, because in all three groups — Cystids, Blastoids, and
Crinoids — there are many forms in which no stem is found, and some that
apparently never had any. The latter is probably the case, among Crinoids,

• Uovisinii, Part 111. p. 7S.

■f CImllpiiffcr Report on the Stalked Crinoids, p. 193 el tej.

t Calamocriuus Diomcdie, p. 8.

SYSTEMATIC I'AUT.

145

i I

in Marsupltes nnd Uliilacrinus ; while A(j((ssi::nrriniis, EJrlocrlnus, and the
Comiitiilu) are steiiilews in tlio niUilt. Among UliwtoiJrt, the stt-iii is wiiiiting
in PcntaphijUum, Triccdocrinm and Blcul/urovrinus ; and thin is the cuho nlso
in a largo number uf Cyntida. The three divinionsi undouljtudly are nearer
related to each other than to any of the other groups of the Eehinoderins,
'lot 80 much by reason of the stem, as because their habit of life is with the
aouth upward, the body lying on its back or growing on a stalix, in contrast
with the habits of Starfishes, Ophiurids and Urchins, which ciiiwl about
mouth downward, and the Ilolothurians, which swim with the mouth side-
wise. Upon those characters, perhaps, the Echinoderms might be conveni-
ently separated into three great groups ; but in that case a new name should
be adopted in place of " Pelmatozoa."

We arc now prepared to accept the Crinoids, Cystids, and Blastoids as
separate groups of independent rank ; but what may be their exact relative
importance, that is to say, what should be the exact size of the compartments
to be provided for them in the scheme of classification, is purely a matter of
opinion, and not of great consequence. The tendency of authors is more
and more toward recognizing them as groups well distinguished from each
other, and they are now ranked generally as independent classes.

There is in our opinion not tho slightest doubt that the " Crinoidca," as
proposed by J. S. Miller in 1821, were limited to Brachiate forms, or, to
be technically accurate, to the Stalked Echinoderms with "articulate arms."
This is clearly shown by his definition,* already quoted by us in a previous
chapter. While including among his species both recent and fossil forms,
Miller did not refer to his Crinoidea a single Cystid or Blastoid, although
both must have been known to him. Cystids are abundant at the Dudley
locality, from which he described some Crinoids, and a Pentrcmitcs had been
figured in 1808 by Parkinson in his " Organic Remains," — a work with
which Miller was no doubt familiar. The name " Crinoid," in tho strict sense
thus employed by Miller, has been sanctioned by the usage of practical natur-
alists ever since, and in our opinion all attempts to strip the term of its
familiar signification, either by enlarging or restricting its meaning, will
prove abortive. If von Zittel, instead of a new name for the Crinoids, had
proposed some appropriate term for the larger group, — to include the
Crinoids, Cystids, and Blastoids, — it would have been a very desirable im-
provement, and we believe would have been generally accepted.

• Natural History of the Crinoidca, p. 7.
19

TIIK (KINOIDK.V CAMKUATA OF NollTir AMI'.UICA.

Wliilo ntllirring, tlioreforo, to tlio original (lofmition of Millor for tlio
CriiioitlH, ami ri'cogiii/.iiig tlio niiintoidH ami (.'ystitis aH tlislinct groiijw, of
rclafivt'Iy equivalent rank, wo have to ao. .it tliat tin; tlirec typCM are con-
nected by a number of rcnuirkalde intermediate forinf), and that it \h ex-
tremely ilillicult in many ciihcs to ascertain wlietlier certain forms arc Crinoidn
or CyntidH, or CyHtids or IJhiHtoidH. It ImH been Htated that CrinoidH and
BlastoidM are distinguinhed from CyMtids by their di!<tinct penfamorouH nyni-
metry ; that the Blastoids and C\ Htids, as nppoHcd to the Crinoidn, have no
trucnrmH; that the HlastoidH have hydroMpires, the Cyntids calycine porex,
ifc. ; but the best of the»o characters meet with exceptions. Wo find in
certain Blastoids, and also in Tiamcrliius from the Devonian, and ZiiphiHrinun
from the Upper Silurian, only four radii ; and even as late as the Mesozoic
there are among the Plicatocrinidiu speciox with three, four, and nIx rays.
P(ir<)cr!inis Imm tho calyx and arms of a Crinoid with calycine pores of ii
CyNtid. IIij1)i)i'ijmIis has stumps of arms with recurrent anil)uhicra on throo
of its rays, and on tho other two rays calyx ambulacra, which pass down
the cup as far as tho basals. The genus was described by Wetherby as a
Cystid, by Etiieridgo and Carpenter as a transition form between Crinoids
and mastoids ; while we have regarded it a Crinoid with strongly persist-
ent Cystidean characters. Cdryorn'ntii*, which has always been considered
a Cystid, has segmented pinnule-bearing arms like a Crinoid ; but it has
calycine pores and hydrospires, and according to Carpenter six rays. Codnstcr
was made a Cystid by E. Billings, by Etheridge and Carpenter a Blastoid.
Stij)h(tnoi'ri)iiis was placed by Roomer among the Cystids, by Etheridge and
Carpenter among the Blastoids, and wc take it to bo a Crinoid. AsterohhistuH
has calycine pores like a Cystid, ond ambulacra and pinnules like a Blastoid.

These, and other facts that might be adduced, point to a common origin ;
but what may have been tho exact line of derivation between the three
groups is a problem that is difficult to solve. They are found side by side
in the Lower Siliuian; but while tho Cystids ceased to exist at the end
of the Devonian, and the Blastoids at the close of the Carboniferous, the
Crinoids survived to the present day. From this it seems to be evident that
the Cystids, as the lowest in rank and earliest in time, were the ancestral
type, and the progenitors of tho other two ; but it is possible that the Crinoids
preceded the Blastoids, although the latter became extinct before the close
of Paloeozoic time.

That the origin of the Crinoids must have dated back far beyond the

HYMKMATIC TAUT.

147

Silurian and perliiipN Ciinil)i'iiin age, U indicated by tlio lii^li nUxto of dcvilnp.
nient wiiicli Huntu of tlicir Iuiiiih hud ai-(|iiii'i-d hh vnv\y an tliu Ticntun
Hi'oup, wliL'n they liad in Moino ciinfrf ahnost coiiiplctuly thrown ulV their
CyHtid ciiamcterH. A Htriiiing exaniplu of tliiH nniung the Canierata Ih (teen
in the genns (thjiitorrintw, in wliicli wo find associated with certain primitive
charactern a hi^h degree of perlection. It m less perceptiiile among the
Inadimata, in which, notalily in tho llyhocrinida', OyHtidean fcaturoN arc
strongly intermingled with the characters of the larval Crinoi<l. IJiit even
ninong them it is imposxihle with the knowlcdgt' wo have, or are likely to
obtain, to form a conjecture as to the group of Cyst ids from Mhich they are
originated, and this is readily explained if we consider that the two typos
followed independent lines of development, and departed from one another
more and more in geological time.

The general tendency of the Crinoid t; pe, taken as n whole, has been
towanl jjcntamerous symiMctry, and in tliis ti.ey ditTor oswentially from most
of the Cystids. But the jientamerons tendency had to struggle with other
tendencies, which in various ways from time to time carried one or the other
of the subordinate groups far off in otler directions. A disturbance of this
kind was caused by the introduction ^f anal p' os, by means of which the
l)entamcrous symmetry wa« temporarily distu; 1 by a bilateral one, which
for a time threatened to overshadow the for,,icr, imtil finally after the elimi-
nation of those plates the pcntame > :v ynimetry was iinanently leotored.
The phases through which the a' .il p^ les pa.ss in geological time in the
various groups arc well represented by individual growth in fi ' ! rva of
Anifddii, and have proved to be excellent characters for family and generic
divisions.

The earliest fossil Crlnoids have no special anal plate, and were more or
loss strictly pentamerous. Among the Lower Silurian Camerata the nnal
X is represented only in the Reteocrinido) and in the abberrant genus Co)iij)-
socrhiits ; in all others the plate is wanting. It is absent also in the genus
Ichthi/ocrinus, one of the earliest forms of the Articulata, and, as we think,
the precnrsor of a large series of genera with anal plates. It piol)ably
was represented ear'' '• in the Fistulata than in the other groups, as might
be expected, for ai: w them all tendencies toward further development
seem to have been exhibited upon the posterior side.

But there were other influences, not due to the anal plates, and not di-
rectly traceabbr! to anything shown by embryology, which not only disturbed

148

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

the radial symmetry, but the bilateral as well, and strongly siiggest that
the Crinoids hud to wrestle for a long time with the tendencies derived from
their Cystid antecedents, manifesting themselves in a variety of irregular-
ities, which from time to time characterized special groups. Such are the
presence of compound radials in one or more rays; the variations in the
form and composition of the proximal ring in the base ; the non-arm bearing
radials of Bacrocrbius, Atdextucriims, and IVibracldocrinus ; the irregular
number of radials — more or less than five — of the Plicatocrinidoc ; and
the almost complete obliteration of symmetry among the Pisocrinida) and
Calccocrinidao.

The division of the Crinoids into two orders: " Palococrinoidea " and
" Stomatocrinoidea " WiXs proposed by us on account of the apparent differ-
ence in the conditions of the actinal portions of the calyx, whereby mouth
and food grooves, and the ventral disk generally, of all Pal.Tozoic Crinoids,
without exception as we supposed, was covered by a special integument —
the "vault" of antecedent literature — instead of being external and exposed
to view. With the knowledge we then had this seemed to be a character
morphologically of extreme importance, and it was so regarded by others.
Under the order Palivocrinoidea we placed all Crinoids with covered mouth
and closed food grooves, and under the Stomatocrinoidea those in which
mouth and food grooves are exposed. The two groups were accepted by
Carpenter, but he changed the name of the latter into " Neocrinoidea."

Anotlier classification was introduced by Ncumayr,* who proposed the
name " Ilypascocrinoidea " for all Crinoids in which mouth, ambulacra!
vessels, and SaumpUittchen (the latter if present) are beneath the tegmen ;
and the " Epascocrinoidea " for those forms in which the ambulacra are not
covered by the tegmen, but have external grooves, which are either exposed
or closed by movable SaumpUittehen. Under the latter he arranged all recent
Crinoids with our Fistulata; under the former the Ichthyocrinidae and Haplo-
crinidne together with our Camerata. It is surprising that Neumayr's classi-
fication, while based like ours upon the condition of the mouth and surround-
ing parts, led to such different results. This must be attributed largely to
the interpretation which he gave to the disk of Cijatliocrinus, in which he
took the vacant space found in the centre of imperfect specimens for the
mouth, and to the fact that he was unacquainted with the ventral structure
of the Ichthyocrinidas.

• Die Stammc dcs Thierreicbes, 18S0, p. 462.

SYSTEMATIC PART.

149

When we discovered that the ventral surface of Taxocrinus, and probably
of all IchthyocrinidaB, is covered by a disk almost like that of recent Crinoitls,
and that it possesses an open mouth and open food grooves, it was instantly
apparent to iis that a division upon the line of Palaeozoic and Neozoic
Crinoids could no longer be maintained. Tiie moment this truth was
recognized, it was found to be reinforced by other considerations wliich were
fully set forth by us at the time.* It might have seemed practicable to
retain the two grand divisions upon the same characters as before, by trans-
ferring the Ichthyocrinida) to the division containing the recent Crinoids ;
but this would have made a change of the names unavoidable. Besides, the
fact chat those characters go back as far as the lowest Sihu'ian was enough
to suggest the gravest doubts whether the particular condition of the ventral
covering was morphologically as important as we had supposed.

About the same time we came into possession of specimens of the
Camerate genus Platycrimis with orals almost perfectly sj-mmetric, and the
covering plates of the ambulacra most regidarly arranged. Considering that
in this same genus there are species in which the tcgmen is composed of as
heavy plates as in any Actinocrinus with subtogininal ambulacra, the con-
clusion forced itself upon us that the plates of the tegmen in all these forms
represent the same element, and that the most rigid "vaidt" of Palaiozoic
Crinoids is but a modifled disk.

The change in our views was announced in our paper on " The Perisomic
Plates," t in which we gave up the Palaiocrinoidea and Neocrinoidea as
natural groups, and proposed in place of them the Camerata, Inaduiiata, and
Art'miluta.

A separation of the older Crinoids into three divisions was attempted by
us as early as 1877, and all that we have since learned, whether through our
own observations or those of other.s, has tended to confirm their viilidity.
Now that we have got rid of the imaginary line between Palosozoic and
later Crinoids, we can better realize the importance of these group.s, espe-
cially since we find that they can be applied to all Crinoids, recent as well
as fossil.

We regard as the most important characters for dividing the Crinoids
into orders : —

1st, the condition of the arniB — whether free above the radials, or partly incorporated
into the calyx.

Proc. Acad. Nat. Sci. Phila., 1SS8, p. 350, et itq.

t Ibid., p. 343.

150 THE CRINOIUEA CAMERATA OF NORTH AMERICA.

2d, tlio mode of uiiiou between tlie plates of tlie calyx — whether movable or

iiiimovable.
3d, the eoiiditioii of the stem — whether the young joints were formed beneath tlio

proximal ring of the calyx, or beneath the top stem joint.

The inorpliologiciil importance of these characters is shown by the fact that
among the earlier Crinoiils tiiey appear as well defined as among tlio.se of
later epochs, which indicates that the origin of the three gronps dates back
to a much earlier time.

The Crinoidea I\.\dunata represent the simplest form, their dorsal cup
being composed invariably of only two rings of plates, or three when infra-
basals arc present. It has no supplementary plates, except nn annl piece,
but this is not represented in all of them. The radials at four sides of the
cup are in lateral contact, and the arms are free from the radials up.

In the structure of the ventral disk we recognize two different plans;
the one exhibiting the utmost simplicity, being com])Osed exclusively of five
large oral plates forming a pyramid ; the other showing considerable com-
plexity at the posterior interradius, which is drawn out into a sac or tube.
Upon these two plans we divide the Tnadunata into two subgroups: The
Inadixata Lai!VIFOr.mia, and the Ixaduxata Fjstulata, both embracing
monocyclic and dicyclic forms.

The calyx of the Larvifonnia consists of but few plates ; viz. : basals
— occasionally infrabasals — radials and orals, the latter forming a closed
pyramid wliich rests against the radials ; the mouth is closed, and the am-
bulacra are not exposed to view. The arms are simple, non-pinnulate, one
to each ray, and they are composed of long, quadrangular joints which,
except upon the radials. arc united by close suture. The anus is excentric.
either piercing the posterior oral, or situated between the orals and radials,
and is sometimes extended out to the end of a long, narrow tube. One can
scarcely imagine a more complete parallelism than there is between these
ancient Crinoids and the larval state of recent ones, and it was this that
suggested the name of the group, which, as we believe, represents the most
primitive type of the Crinoids generally. That we do not find the Larvi-
formia prior to the Ningnra. but only subsequent to the advent of the other
groups, may be accounted for by the pmall size of their species. The calyx
of AUfujerrimis Ausiinii from the Scotch Carboniferous is no larger than
a small grain of sand, and it is vorv possible that the earliest forms were
altogether microscopic. The total absence of supplementary plates, and the

n-^

' ^

SYSTEMATIC PART.

lol

compound nature of the radials in the eiiriier forms, are other primitive
features characteristic of this group.

The Fistulata, in a general way, agree in the structure of the dorsal cup
with the Larviformia. But while in the latter the disk is simple in the
extreme, that of the Fistulata is highly specialized by means of the extrava-
gant development of the posterior interradius, forming a tube or sac which
often is drawn out to the full )'>ngth of the arms. The sac rests upon the
radials or is supported by the anal x, and frequently — not always — con-
tains the anus. Owing to the large size of this sac, and the disturbances
thereby produced, the whole calyx acquired a marked irregularity, which
was still further increased in species with compound radials, so that the
pentamerous symmetry, and the bilateral also, were often supplanted by
asymmetry. The other interambulacral areas are but feebly developed, and
are pushed over toward the anterior side. The anal opening is situated
near the top of the sac, or at some place along its anterior side, and some-
times in front of the sac close to the mouth. The sac, at least in some
groups, is pierced by pores, which we think had respiratory functions,
similar to the water pores of recent Crinoids, in which also they are more
profusely distributed at the posterior area than at any of the four other sides.
In some groups, in which the sac is not perforated, we discovered upon the
disk, directly behind the mouth, a poriferous plate, a sort of madreporite,
which probably performed the same functions as the pores in the others.

The CiMNoiDEA Camerata have a largo number of supplementary pieces,
which are distributed almost equally throughout the five sides of the calyx,
by means of which the proximal arm plates for some distance are incor-
porated into the calyx, thereby increasing the capacity of the visceral cavity.
All plates of the calyx are heavy and immovable, being united by close
suture. The symmetry of the dorsal cup is either strictly pentamerous or
sub-bilateral ; we never find that asymmetry which is so characteristic of
some of the Fistulata. The base is monocyclic or dicyclic, and mouth and
food grooves are perfectly closed.

The CiuxoiDEA AuTicuLATA agree with the Camerata in that their lower
l)rachials take part in the calyx, and help to enclose the visceral mass ; but
their plates from the radials up are movable. The incorporation of the
brachials took place by lateral union among themselves, by the introduction
of supplementary plates, or by means of an incrusted or naked skin ; and
mouth and food grooves are exposed upon the disk. The base is dicyclic.

152

THE CRIXOIDEA CAMKRATA OF NORTH AMERICA.

I' ^

but the infrabasals arc fused with the top stem joint, which throughout this
order is not the youngest joint of the stem.

To the Articulata we refer the Ichthyocrinidaj, and all Meso/oic and later
Crinoids — recent and fossil — in which the new stem joints are introduced
beneath the top joint. They are divisible into two suborders : —

I. The Articulata Impinnata, to include the Ichthyocrinidaj which are
destitute of pinnules.

II. The AitTicuLATA PiXNATA, to include those families in which pin-
nules are present.

Tliat there exists a close resemblance between the Ichthyocrinidic and Coma-
tula) — especially their earlier .stages — is well shown by our illustrations
on Plate VI. Figs. 13 to 20, and it is worth mentioning that no other form
has changed so little in geological time as the genus Ichlhijocrinus, which
survived from the Lower Silurian to the Coal Measures, and which may be
regarded as the ancestor of all Articulata.

The name " Articulata " was proposed by J. S. Miller, and adopted by
Johannes Midler for a subdivision of the Crinoidea. The former referred to
it Ajjiocriniifi, Encnmis, and Pentacrlnns, to which Miiller added the Coma-
tulao. He defined the group as one in which the lower ray plates are con-
nected laterally by a skin, which may be naked, or paved with irregular
plates. From this definition we judge that his ideas of the group were
substantially the same as ours, and we believe if Miiller had known the
Ichthyocrinidtv, he would have placed them together with the Apio-
crinidiv and Comatula?. His definition, however, is not complete enough,
and it admits forms which in our opinion are widely different. We al-
lude to the Encrinidtv) and Pentacrinidic, which differ from the Apio-
criniihe and Conuitulae in having the uppermost joint of the stem the
youngest joint, whereas in the latter two it is not. That Miiller admits
Paitacriniis into this group we can understand — its lower brachials actually
are united by a skin — but it is difiicult to .see why lie added the genus
Eiwriims, in which the rays are free from the radials up. The Pentacrinidiv
have through the Encrinido) close affinities with the PotcriocrinidoD, and are
probably their descendants; but if they are Inadunata, thoy represent an
aberrant type, for their lower brachials, as stated before, arc enclosed in the
calyx. This departure from the Inadunate plan may perhaps be explained
if we consider 'hat the calyx of the Pentacrinidao, owing to the reduction of

SYSTEMATIC PART.

153

the ventral pac, was incapable of hokling the visceral mass without incorpor-
ating the lower brachials. As such the Pentacrinidio may represent the last
survivors of an exhausted type, or they are the progenitors of a new group.

After eliminating from the Articulata the Encrinidte and Pentacrinidoc,
and all Crinoids in which the top stem joint is the youngest joint of the stem,
we have a well-defined group ; but it may be asked whether tlie name
Articulata c;in be retained for a group thus restricted and redefined. The
name is most appropriate, and as the group is based largely on the character
of Mliller, we think it is just to the author to adopt his name. In case, how-
ever, other writers conclude that this course is inadmissible, we propose llie
name " Articulosa" to take the place of Articulata, to meet the coutiugenry.

That our primary divisions are natural groups is further confirmed by tlie
orientation of the base, which, when the proximal ring of the base is un-
equally tripartite, varies among the different groups. Comjiaring the
base to tlie dial of a clock witirthc anal side at 12, it may be said tiiat in
the Impiimata the .smaller infrabasal points to 2 o'clock; in the dicyclic
Fistulata,* so far as observed, and in the Antcdon larva, according to Bury,
to 6 o'clock ; and that the small basal in monocyclic Crinoids generally
points to 7 o'clock, contiary to all Blastoids, in which it points to 5 o'clock.
We have no explanation of these facts to offer, but tlicy doubtless have an
important bearing upon the derivation of the groups.

It is now well establi-^lied that the value of a character for classificatory
purposes is not always in proportion to its physiological importance ; but
depends more on its constancy throughout groups, and its correlation with
other characters. I'he characters of any group are not fixed and rigid, but
w must always be prepared to find as to one or more of them variations or
departures from the typical form, indicating a transition toward, or con-
nection with, some other group through that particular feature. We cannot
expect absolute persistence of any one character, whether specific, generic,
or ordinal, and the larger our collections the less persistent and fixed will we
find the separate characters. But if we are reasonably happy in our identi-
fications, we may expect to find greater reliance to be put upon llie corre-
lation of characters, .so that while one or more of them will show a tendency
to departure, the sum of all will exhibit a predominance which will liold the
form in question within the given group. There is no hard and fast rule by
which it may be determined that a certain character is of " family " or
" generic " importance. It may bo the one or the other according to cir-

• This dues not liolil good for the Fistiilritn since Mr. Unllior — Criiioiilrn of Gotlniid, Vol. I. p. 152^
Ims found tlint the poaitiou of tbo small infrabasal is not coustint iu the Gjtland species of Giuocrinua,

154

THE CRIXOIDEA CAMEiiATA OF NORTH AMERICA.

ciimstancos, iind about all we can say of tlie " value " of any character ia
that its value is proportional to the extent to which it tends to combine
subordinate groups. As n rule we may say that a character which j)asses
down to earlier geological epochs, is of greater value in classification than
one dating from u later period.

It hah been stated that the supplementary plates afford excellent charac-
ters for dividing the Crinoids into primary divisions ; but they are also of
great importance in the separation of families. It may appear singular that
plates whoso chief function it is to fill up spaces between other plates, and
which are of but secondary importance morphologically, should have so
great a value in classification; but such is undoubtedly the case. The elimi-
nation of those plates from the calyx would reduce all Crinoids to a single
group, and tlicse would all be Larvilormia. The introduction of sup|)lo-
mentavy plates into the simplest Inadunate type produces the Fistulata,
Camerata, and Articulata, and all in their individual development necessarily
passed through the Larviformia stage.

Among the supplementary plates, the anals unfjucstionably take the first
rank. Tiie absence of anal plates, their introduction into the calyx, and the
relations they bear to adjoining plates — whether introduced between the
radials or l)rachials, or between both of them — has been regarded as very
important ; but the same characters have not the same classificatory value
in every group. The differentiations produced by the anal plates have been
considered of fiimily importance among the Camerata, but among the Fistu-
lata and Tmpinnata appear to be of generic value only.

The nature of the base, whether composed of one ring of plates or two, is
a valuable character for distinguishing famili'^s, but we tiiougiit it expedient
to make an exception to this rule in the case of the Reteocrinida*, under
which we have united monocyclic and dicyclic forms. The number of basals
and infrabasals is of generic value only.

The occurrence of inferradials among Inadunata and Articulata, and the
modifications they undergo paltrontologicall)', and their final disajipearance.
have furnished good generic characters.

Somewhat less intportant from a classificatory' standpoint is the number
of costals, although it was made a generic character among the Camerata;
while in the Fistulata it has in some cases no significance at all.

The general structure of the disk affords good characters for dividing the
Crinoids into ordinal and subordinal groups. It was the total absence of

"> i

, f-

SYSTf:>IATlC PART.

155

perisomlc plates in the disk that suggested the Larvifoniiia, and the sac-
hlie prolongation of its posterior area tlie Fistuhvta ; all Cauiorata have
a rigid disk, contrasting therein with the Articulata in which the disk is
pliable.

Tlie condition of the ambulacra, whether resting \ipon the tegnicn or
being incorporated into it by means of their covering pieces, or whether
constituting open furrows upon the disk, is of more than family importiineo ;
but the exposure of the covering pieces, and their concealment wholly or in
part by the encroaching perisonie, are not even reliable generic characters.

The presence or absence of orals, and their greater or loss symmetry or
asymmetry, have very little classificatory value, except in the Larviforniia,
in which they are the only plates of the disk.

The condition of the anus, whether in form of a simple opening directly
piercing the calyx, or situated at the end of a tube, has been generally
regarded as of generic value.

Of considerable importance is the presence or absence of pinnules, which
is correlated with other characters by which very large families are dis-
tinguished, c./^., the Cyathocrinida) from the Poteriocrinidae ; and it is the
name-giving character of the Pinnata and Impinnata.

The condition of the arms, their simplicity, their mode of branching, and
the arrangement of their plates — whether uniserial or biserial — afford
useful characters for distinguishing genera; but as all biserial arms are
derived phylogenetically, as they are embryologically, from the uniserial
ones, it must be expected that at a certain time both structures occur side
by side in the same genus.

The construction of the stem, the form of the joints, the length of the
internodes, have comparatively little value in the classification of Palaeozoic
Crinoids, and are of generic value only in rare cases. Perhaps if the stems
were oflener and more completely preserved, it would help in the identifica-
tion of species.

With regard to species, their recognition is to a considerable extent the
expression of the individual opinion of the observer, and in large collections
it is often difiTicult to distinguish between species and variety. So long as we
have to deal with new forms, represented by unique specimens, the task is
simple enough. But when large numbers of specimens are brought together,
in dilferent states of preservation, presenting different conditions of growth
and size, and exhibiting the various shades of individual variation, it is not so

t ;l

156

THE CRIXOIDEA CAMKRATA OF NORTH AMCTICA.

easy to discover and di-fiuo the points by wliich ccrtiiin nsseinblnges of these
iiidivitluiilM agree with each other, niul diller from others, witii siidicient con-
stancy to be called species. With but a single specimen in hand, and this
imperfectly preserved, as is oftin the case, it is impossible to decide whether
we have a good species or a mere variation, whether it is tlio young or the
adult; and whether or not the distinguishing character represents a mere
abnormal condition of some established species. In describing new species,
therefore, the utmost caution is re(iuired, especially since the number of
described species in America alone has increased to almost fifteen hundred.
That a specimen comes from virgin soil, distant from any other known
locality of the same horizon, does not make it a dillerent species. The
geographical range of species is much wider than formerly supposed, and
careful comparison with authentic specimens of allied forms must always be
made before a form can be recognized as a valid species. Among tlie char-
acters to be considered as most important for distinguishing species, we
recognize the form and proportions of the calyx; the relative proportions of
the plates and their ornamentation ; the number of arms and arm openings,
the direction of the latter, and their distribution around the caly.x, whether
continuous or separated by the supplementary plates; the form and position
of the orals, whether flat or tumid, symmetrically or asymmetrically arranged ;
the presence of "radial dome plates" or regular covering pieces, and other
characters of a more specialized nature ; not forgetting that some of them
depend on the more or less adult condition of the specimen, and its preserva-
tion, and that in certain groups some of them are wholly worthless.

That a given character mav bo good in one group, and without any
value for classification in another, is a fact so fully recognized at the present
day that there is no need of citing instances to prove it. Every working
naturalist has encountered striking illustrations of its truth.

To facilitate the identification of species among genera containing
a largo number of forms, we have arranged our descriptions so as to place
species which are most clo.sely related next to each other, thereby en-
abling the student to make satisfactory comparison with allied forms. In
Plafi/crhuts, which contains an unusually large number, we have arranged
the species into subordinate groups.

It is not our intention to go into details upon the classification of the
Inadunata, but a ."^hort review of them will be necessary for this work.

We have stated that we divide the Inadunata into Larviformia and

SYSTEMATIC PART.

157

Fistulata. The former embrace tlie fftmilies IlnplocrinidoD, Piaocr'mi(]a\
SymbathocrinidoD, niul CuprosHocrinidao; the latter the Ilybocrinida^, Iletero-
crinuluD, Anomalocrinida), Belcmnocrinidao, Gasterocomido), Catillocrinidip,
nnd Calceocrinida) of monocyclic forms, and the Dcndrocrinldao, Cyathocri-
nidoD, Potoriocrinida), Astylocrlnidro, Eiicrinidas, and Pentacrinidaj among
dicyclic forms. The arranj^cment is substantially the same as that proposed
by us in 1885, in Part III. of the Revision, except that we withdraw the
GasterocomidoD from the Larviformia, and jilace them among the Fistulata.
This change was announced by us in 1890,* when we restricted the Larvi-
formia to those Inadunatu in which the orals rest against the radiala, nnd the
ventral surface is covered exclusively by the < i ils, i. e., Crinoids which
remain persistently in the larval state.

A dilTerent division of the Inadunata has been lately proposed by Mr.
Bather,t who subdivided the Inadunata into " Monocyclica " and " Dicyc-
lica ; " but whether they should be ranked as suborders, he leaves as yet in
doubt. In alluding to tiie Larviformia and Fistulata, Bather says these divi-
sions " cannot well be maintained. Many genera hitherto included in the
Larviformia have quite as good a ventral sac as some acknowledged Fistu-
lata." We do not know of any group to which this remark can be applied,
unless Mr. Bather undertakes to homologize the narrow anal tube oi S;imb(itho-
crimts and Pisocrlnns with the ventral sac of the Fistulata. Sj/mhat/i(irrhuis
has no ventral sac, but simply an anal tube, nor has it an anal jilato, or
perisomic pieces as we once supposed ; its asj-mmetrical oral pyramid rests
directly upon the radials, and its anal tube is supported by the radials and
orals together. Bather further says : " they (W. and Sp.) excluded Ilctcro-
criiiKs and Calceocriniis, in which it has at all events never been proved
that other plates beside orals occur in the tegmen." We supposed it was
now admitted that the ventral sac represents morphologically the highly
developed posterior inter-palmar area of the disk, as was proved by the
position of the anus, which is situated either at the imlerbr side of the sac,
or not within the sac at all, but in front of it (toward the oral centre) in ihe
main part of the tegmen. Admitting this, the presence of the sac proves
that the Ileterocriuidao had a complicated di.sk.

The case is very similar in the Calceocrinida) and Catillocrinida3. IjoIIi
agree with the Larviformia in having no anal plate, at least no anal x; but

» IVocfcd. Acad. Xat. Sci. Pliila., 1S91, p. 335.

t 'i'liu Criuuidca of Uutlaud, I'urt I., willi tcu plates (Stockholm, 1893), p. 20.

I ;

158

THE ClUNOIDEA CAMEKATA OF NOUTII A.MEUICA.

there are roHting upon tlic rndiu1» what wu tiiko to be plates uf tliu tube.
ThcMC i)latoH, which are crcsccut-Hliapcd and extroiiifl^' heavy, are longitu-
dinally arranged, and puna np to near the top of the arniH. The relation of
these plates is not altogether clear, but they probably represent the heavy
and solid plates ot lucriiiun, which constitute the ridge along the posterior
side of the sac ; and we believe that the oi)i>n groove at the anterior side was
in the animal filled, as in the case of lucrimis, by small disk plates, which
may or may not have been perforated. This interpretation seems to us
the most probable, and u[ion the strength of it we have placed both families
under the Fistulata.

Bather's definition of the Monocyclica is short: "Inadunata with no
infrabasals." But notwithstanding its brevity it meets with two exceptions:
Cttpressocrinus and Mi/rtiloc.rinua, which Bather referred to the Monocyclica
with some doubt; both have an infrabasul disk. It will not help the matter
to say that the plate in both groups is a top stem joint (centrodorsal), for the
condition of the plate in Cupres^Dcrlnm, as well as in Myrtilocrimis, is very
difTerent from that under which the centrodorsal occurs in the Apiocrinidtu,
ComatuluB, and Ichthyocrinidao. Wherever that plate occurs, it is in dicyclic
Crinoids, and the infrabasals are fused with it. When the fusion is complete
there appears in place of the infrabasals a vacant space at the inner floor of
the calyx between the basuls; nothing of which is found in these two genera.
Besides, the plate does not rest against the outer faces of the basals, as it
should do if it were a top stem joint, but against their inferior faces, like
the infrabasals of true dicyclic Crinoids.

Mr. Bather alludes to a structural peculiarity, which he thinks has "more
weight in the classification than the varying extent of tegminal develop-
ment." He says: "It a ill be seen from the ensuing remarks on Pisucriiius,
Calceocnnus and Ilcrpctocrinus, that a very large number of Inadunata Mono-
cyclica closely resemble one another, either in the horizontal bisection of
certain radials, a character which in Dicyclica is entirely confined to the
right posterior radial, or in the greater development of certain other radials."
He overlooks the dicyclic Tribrachiocriiuis, which has three compound radials,
and we find on examining the genera which he referred to the Monocyclica,
that among the twenty-four only eight have three compound radials, and
sixteen have not. Among the latter there are three with two compound
radials, Anomalocrinus, Ohiocrinua, and Bacrocrimis,* and three with a single

* III tlie latter, as we uudcrstaud the structure, oul; the iufcrradiah became developed, but uut tlic arin-
beariDg section.

8YSTKMATIC' PART.

150

c^q; tho remnining ton gonora liavo simple radiiili tlironghout. Neitlier do
wo (iud any rLMiiarkiiblc dovolopiuoiit of cortaiu lii'lials, oxccpt when IIr-mc
ttro compound. All tliis is soriouHly in tlio way of inaiting the presence or
abHcnco of infnibaHals a Hnbonlinal character.

Bather claims tliat among the Dicyclica doparturos from tho pcntamcroim
Byminutiy of the cup plates occur only in tho right posterior radial. E\cop-
tions to thi.H, however, are found in AtdcstnrrinKH ami iVr(//"(v///»,«(, in wiiich
tho Hyminetry is disturbed by the anterior radial, and in the hitter genu-i by
tho right antoro-latoral together with the anterior.

Bather's researches were largely devoted to the Dicyclica of the Niagara
and Wcniock age, whidi ho divided into three principal families; tho '♦ Den-
drocrinidfc," tho " Cyathocriiiidiv," and the " Decadocrinida" ;" and in addi-
tion to them he recognized two smaller families, the " Euspirocrinidu) " and
" CarabocrinidoB," the latter imroprcsontod in Enrupo.

The Dendrocrinidio are defined by him as follows ; " Dicyclica, with li'
alono, or with anal x alone, or with li' and anal .c, or with a radinnnl, anal
X and one plate of the tube, in the anal area of the dorsal cup ; with broad
radial facet; with dichotomous arms, that may or may not develop pinnules;
with a togmen compo.sod of small plates, and with a ventriil tube that is
unusually long and transversely flattened." Ho states that tho family is
distinguished from tho Decadocrinidio by the continuous dichotomy instead
of tho single bifurcation of tho arms ; th.it their anal x% unlike tlmt of (he
Cyatliucrinidao. is always associated with other anal plates; that the radials
have a wide, slightly specialized flicet ; and that their tegmen is more
delicate. The Dendrocrinidio are said to be rei)rosented in America in
the Hudson River group by Dimlrorrhuis, in tho Devonian — both in this
country and in Europe — by /fi))iiorriniis, and in the Carboniferous by I'liri-
snrriiuix, Potcn'orrlniis, and Srnp/ilncrlniis. which agree in the structure of tho
anal area; tho three latter with pinnulo.s. tho former without them. 'I'he
presence or absence of pinnules, and the structure of the arms, he makes the
leading characters for distinguishing the genera.

lie defines his second family, tho Cyathocrinidnp, as having "no radianal
or tube plato in tho anal area of the dorsal cvip ; with anal .r either pros-
ent in tho cup or raised above it; with five arms, simple and dichoto-
mous; with tegmen rather solid." Ho refers to it Ci/ti(/iorrin>is, Gisuncrinua,
and their descendants, with the subdivisions Cyathocrinito.s, Achradocrinites
and Codiacrinitos, of which the latter have no anal at all, and some of their
gonora have an inferradial, or a radianal, while others have not.

ICO

TIIK CUINOIDKA CAMKIlArA OF NOIMIl AMI.IMCA.

The Deciulooriniilii', liis third fiiinil}-, arc (li'linutl an IoIIowh: " Dicyclica.
in wiiicli tlic) iinii.i birurcato; uaeli iniiiii braiu'ii hoarin^ annlcts ur pinriih ;
with from iiutiu tu three aiiul phites in the doixal cu|), Hiipportin^ ii CiU" >'•
which the lunieii is uMuaily llaltenoil traiisvci'.Hely, uiul tiie plates piiea. ' ' ,
with a tegmen composed of niiinerous Hiiiall plates, very rarely distinguish-
able." The family is said to einbraeo such forms as Udtn/orriiiun, Jhirij-
erliiKs, AlilcntocrinuH, Sri/tnlopriiius, and finally OucoerinuH, Jiiijifir/ii/crinits,
Ste>ii)iiiiti)rr!niis, n\\i\ IJnrriints, — in our opinitm the most hoterogom-ous as-
semblage of genera imaginable. It is not even true that they all iiave ten
njain arms ; some of them have but five, others seven, nine, twelve, or even
fourteen; and these modifications apparently occur within the limits of
a genus, — proof enough that the number of arms is a most unreliable char-
acter in classification.

Another objection is that the family includes forms with pinnules and
uithout them. Bather's views respecting the pinnules are rather peculiar.
He cxprcs.ses the opinion* that the development of pinnules by itself
cannot bo taken as a character indicative of divergence, and he under-
takes to prove this by the genus JJutrj/orriiiiin, of which lie a.«serts that
" the Swedish species have armlets and not pinnules," but " the coimiion
Dudley species undoubted pinnules." That the appendages of the latter are
pinnules and not arms, he probably deduced from the fact that the branches
of this species arc somewhat smaller and arranged regularly from alternate
joints. In discussing the evolution of the arms. Bather a.ssumed t that
armlets preceded the pinnules, and that when finally the armlets became
small, ceased to branch, and wore regularly placed on alternate sides of
successive joints, they were called pinnules. This explanation is not satis-
factory, as it woidd indicate that the smaller appendages are derived from
the larger ones. It seems to us more probable that the arndets are true
arm branches whoso development was arrested ; and wo believe that every
species o( Butri/ocn'niis has armlets, and that pinnules are not represented in
any of them, liolrtjocrlnvs dermhicti/his we take to be morphologically in
a similar condition to Stetjannrriiiua aruncohts (Plate LXI. Fig. 2fl); and we
think that in both of them every joint of the main arms bears an armlet,
whereas those species of lio/n/orriinis in which the arndets are given off at
intervals are in the condition of Stcfjaiiocrinux ncitlptits (Plate LXI. Fig. 1 «).

• Ann. and Mng. Nat. Hist., May, 1890, p)'. 373-3/6.
+ Ibid., p. 374.

BY8TKMATIC PART.

161

But while the nrmlutH of the Silurian /.' h-'mrinuH bear no pinniilcM, thono ttf
tliu SiibciirboniroroiiM Stitjaitorriniin give olT pinnulon from the iiruilctH,

Uiithcr'.'* cliwilicution nml tlicorioM rowpecting tin; evolution of the nrinH
nro open to many critioiMinH, and aro certainly not confirnuMl by a ntudy of
the Carboniferous FiMtulutii. lie cannot put to;^etli('r ccrtiiin Poteriocrinidiv
with (ho Dendroorinidu), and others with the Dccadocriniiln', nor pliice the
non-pitnndato Ilnmncnunn nnd Parinorriinia in a family with piiuiide-bearing
furmR. Ilin claHxification Ih based principally npon two things: the pre.xcnee
or absenco of infrabasals, which ho makes a siibordinul character, and tho
relations of the plates at tlu; anal side among tlieinsclvi's and (ownni adjoin-
ing plates, npon which he separates the families. IK' was iicrliaps not awaru
that in Uta-i/muiis the railianal imiy be present or absent in the same specieH,
and that Parinocn'iwa would bi' substantially identical with C'/iit/incriiiiis but
for the presence of tho radianal. As family characters he olso relics \ipon
the mode of branching in the arms, and the structure of the tegmen, which
latter he has been able to observe in oidy a few genera. The remarkable
development of tho posterior area into a ventral sac, which in 1S!I0 was
regarded by him as an excellent ordinal character, is omitted altogether in
his present classification.

While therefore wo cannot agree with Mr. Hathor upon bis classification,
wo fully acknowledge the excellence of his specific and generic descriptions
in his late work on the Swedish Inadunata, and the many fine observations
which ho has brought out. Ilia discoveries npon the orientation of the radials
in tho Pisocrinida) nnd Calceocrinidni are of tho utmost value, and have
thrown new light npon these difficult groups.

We regard as tho best family distinctions among the Fistnlatn tho
presence or absence of infrabasals, the presence or absence of pinnules,
and the relative size of the ventral sac. The structure of the tegmen, if wo
knew more almut it, might perhaps also afford good distinctions; but tho
modifications that occurred at the anal side of tho cup, and the mode of
branching of the arms, can be utilized only for distinguishing genera. The
biscrial arm structure did not obtain a foothold among the Inadunata imtil
near the close of the Subcarboniferous, and at no time became a constant
character. More important for generic separation is the mode of nnion
between tho radials and brachials, and tho form of the facet — whether
horse-shoe shaped or forming a straight line ; also the form of the ventral
sac, and whether one or more of the radials aro compnnrru.

( .

162

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

The least tloparturo from the structure of the Larviformia toward the
Fiatulata is fouiul in tiie geiuis Cumlocriims, in wiiich the toginen is com-
pose<l of five asyinniL'trical orals, meeting laterally and by their inner
ends, four of theni resting against the rndials, the posterior one being
separated from them by a numljor of irregular perisomic pieces, which
enclose a short anal pyramid. Somewhat higher difierentiatcd is the
tegmen of C'/a/kicriinis d/iifaciiis Angelin — C. rtimomis Bather — (Plate III.
Fig. (l), whose amliulacra are subti-gminal, but the orals are separated
from the radials by a narrow belt of perisome ; contrary to other species of
Cjallmritius, in which the ambulacra rest upon the tegmen, and the orals
are, or seem to be, in a state of resorption. In J/i/lincriiius, the ventral sac ia
as small as in Cunibncninis, and it has large orals resting against the radials;
but the lateral edges of the plates are covered by the SmnupliilkhtH. The
Cyathoerinidie have a large ventral sac, and in the tegmen a niadreporite,
which was prolnildy unrepresented in the Poteriocrinidic, in which the sac
itself is perforatt'il. The ventral sac made its appearance in the Ilybo-
crinidie, Carabocrinidie, and Anomalociinidie as a very insignificant protuber-
ance; in the ^leterocrinidiV, Ik-leuniocrinirue, and especially in the Cyatlio-
crini(la% ami l'oteriocrinid;e, it attained enormous dinunsions, but dwindled
down in the En.'rinidtc to almost nothing, although some of them still have
well defined anal plates. We do not restrict the ICncrinida; to forms without
anal plates, such as Encrinns, S/rmiiititom'iiiis, and Fmocriiiiis ; but include
among them the genera Eiijnirhi/rriniix. Cromt/ncriiiiis, Ciri'ncriiiii.s, luid Oitocriiuix,
in which the anal area passes through all possible transition stages. Vv'e
make the reduced size of ihe sac, and the higldy diflerentiated articulation
between the radials and brachials, the distinctive characters of the fan\ily.

The Camkhata constitute a compact and well limited natural group, and
they are a highly specialized type, which by extraordinary development
reached a stage of extreme difl'ereutiation, and produced a ventral structure
apparently so dilTerent from that of other groups, that it was for a long
time found impossible to homologize its plates witli those of the other
Crinoids. They represent a type of rapid culmination and development,
possessing already in the earliest kncwn forms well defined pinnules, and the
bise-ia! arm structure in most of their families i)eing permanently established
at the close of the Silurian. The organization of the Camerata may not bo
intrinsically higher than that of the otiier groups, but they very clearly
represent a higher state of development than Ilnplocriiiita or SjmlHilhocrinus,

SYSTEMATIC PART.

1G3

in the sense that Acfiiiocriims is n more ndvnnccd typo tlinn Plaf^criiiiis. Tlie
two former represent the larval state of the Cainerata, while PMycriiius is
'I sort of transition form, in which the Camerate stage has not reached its
full development.

The Camcrata existed at the beginning of the Silurian, and survived
to the close of the Subcarboniferous, with a feeble reminiscence in tlie Coal
Measures. But although they developed some very remarkable and short-
lived forms in the Silurian — such as the Calyptocrinidtr? and Crotalocrinida^
— the type is pre-eminently a SubcarI)oniferous one. In that age they
reached an extraordinary development, not oidy in the abundance with
which they flourished, both as to numbers and variety, but also in extrava-
gance of form and size in every one of their leading families. In the lower
Carboniferous the Camerate type .seems to have achieved the summit of
its possibilities, for extinction followed rapidly after, and at the close of the
Keokuk epoch there was scarcel}' a remnant of the typical section left, aiid
at the end of the Kaskaskia the whole group, so far us Pala)ontology informs
us, was practically extinct.

The Cainerata fall naturally into two sections : —

I. Those in which the lower brachials and intcrradials form an important
part of the dor.sal cup.

II. Those in which the brachials retain the form and small size of arm
plates, and the intcrradials are almost exclusively confined to the tegmen.

The first of the-'C represents the typical Camcrata, of which an Adinocrimts
is a charaf'teristic example. It includes the Reteocrinidnc, Ivliodocrinida?, Thy-
sanocriuidaa, Melocrinida\ Calyptocrinidie, Batocrinidiv, and Aetinocrinida).
This section reached its culmin.ition among the Actiiiocrinidiu in the genus
Sh'otocrinus, of which in some species the rays are incorporated as high as the
twelfth order of brachials.

The second, or non-typical, section represents a stage in which the modi-
fication of the Inadunate type by Camerate tendencies oidy progressed to
a limited extent, as shown by PM>/criiiiis and allied forms. It includes the
PlatycrinidiB, Ilexacrinida), Acrocrinido', and Crotalocrinidiu. In tiiis section
the Camerate type was not perfectly attained, but its development was
checked. This may have been duo to the largo .size of the radials. and the
comparatively .small size of the succeeding brachials, which retained perma-
nently the condition of free arm plates. The species of this group are inter-
mediate bet veen the Inadunata and the typical Camerata, their lower arm

104

THE CRIXOIUEA CAME" ATA OF NORTH AMERICA.

joints taking part in the composition of the calyx by nioana of plates wliicli
combine the functions of intoibrachials and interanibulacrals, and which,
properly speaking, arc plates of the disk. Another peculiarity characteristic
of this section is the presence of a large facet upon the radials, in which
tho_ lower brachials are buried, and a brachial of higher rank meets the
interradials, and sometimes the radials.

The question has been asked whether the Crotalocrinidiu should not
be placed under tiie Inadunata, instead of the Canierata. They certainly
represent an intermediate form, having some characters even of the Articu-
lata. But their lower brachials are more or less connected with plates of
the calyx, and the covering plates of the ambulacra, imliku those of the
Inadimate Crinoids, are rigidly incorporated into the tegmen. They are
morphologically in the same condition as tlie other families of this section,
except for the dicyclic base, and represent, as we conceive, only a dilTerent
degree of departure from the Inadunatc plan.

The typical section of the Camcrata appears to have been the first in
time. It was well defined in the Lower Silurian, where it was represented
both by dicyclic and monocyclic form.s, — the Khodocrinidas on the one hand,
and the Batocrinidie on the other. They flourished about the same period,
cidminated together in the IJiu'lington epoch, and disap|)eared almost simul-
taneously, the one in the Keokidt group, the other in the Warsaw limestone.
In the Lower Silurian there was another family — the Reteocriuidiv — in
which the structure of the base .seems to have been subordinate to other
character!?, and we found it advisable to include among them monocyclic and
dicyclic forms ; it was short-lived, not enrviving the Hudson River group.
The Thysanocrinidai and Calyptocrinida), the former dicyclic, the latter
monocyclic, came to light in the I'pper Silurian, with a very small beginning
for the former in the Ihulson River; they existed for a time in considerable
abundance, but perished soon, only a few straggling forms surviving to the
Devonian. Of the monocyclic families, the Melocrinidaa were the earliest,
ranging from the Trenton to the Hamilton, where they seem to have been
abrujjtly cut oif. The other great monocyelic family, the Actinocrinida;,
appeared, culminated, and disappeared in the SubcarboniA-rcus.

The non-typical .section made a good beginning in the Upper Silurian
wi'l: its only dicyclic family — the ephemeral Crotalocrinida> — and the
iiatycrinidsD, represented by five genera, of which four ex])ired before the
close of the epoch. The surviving Platycrinidaa had a feeble representation

SYSTEMATIC PART.

105

in the Devonian, but durinfj the Subcarboniferous attained in the genus
ri(i///rriiiiis a wealth of forniH wiiich had no equal before or afterwards in any
other group. TIio Htrugglo for exi.stence was kept up in this seetion by tlie
IlexacrinidiT) long after the last typieal Canierate Crinoid had disapiioared,
and the expiring effort of nn exhau.sted type ia seen in the Coal Mea.sureH in
the form of the diiuiiuitivo Acrocriiiiis Wuiiheni.

It appears, therefore, that tlie typical Cainerata do not represent the last
of them in point of time, but that either their final efforts at perpetuation
were carried on in connection with a tendenny to revert to the luadunate
type, or the greatest persistence was manifested by that form of the Came-
rata which had departed from it the least.

The change from the pentamerous to the bilateral symmetry consequent
upon the introduction of an anal plate into the ring of the radials. was per-
haps the most important modification that took place during the j)aiieonto-
logical history oE the Camerata, and it occurred within tiie range of our
knowledge of the group. The symmetry of the dorsal cup, which through-
out the Treuton group had been more or less perfectly pentamerous, was
disturbed in the Hudson River group, in both dicyclic and monocyclic forms.
In the former, four of the truncated, heptagoual basals of the Rliodocriuida)
were retluced to pointed hexagons in tiie Tiiysanocrinidfe, and the inter-
radial plates .separating the radials disappeared from four sides, that at the
fifth retaining its position, and serving as an nnal plate. The Rhodocriuidic
were a loug-lived family, appearing in the oldest Silurian, and persisting to
the climax of the Camerata in the Sulicarboniferous, — the strange, extrava-
gant Gilhcrtnomuus being their last survivor ; while the Thysanocrinidae
scarcely survived the Silurian.

Among monocyclic forms the disturbance of symmetry was caused hy the
interposition of an anal plate between the posterior radials, which converted
their pentagonal base into the liexagon of the Batocrinidaj and Ilexncrinida).
The pentagonal base, though reinforced in the Niagara by the (.iilypto-
criniihu, disappeared from the typical Camerata with the Melocriuida' in the
IlamiUon ; while the hexagonal base, with its accompanying anal plate,
continued with great vigor in tiie Batocrinidap and their offsiujot. the Actino-
crinidiP, througiiout the period of greatest development of the group, and
until the extinction of the typical section in the Subcarboniferous.

In the non-typical section, we have among dicyclic forms no example of
a symmetrical base, the Crotalocrinida) having n truncated posterior basal

I I

166

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

aupporting an anal plate. But among monocyclic forms tlie anal plate is
unrepresented in the Platycrinidae, in which the base forms a pentagon.
The intr()(Uiction of the anal plate occurred in the Hamilton group, and
produced the hexagonal ba.se of the Ilexacrinida). The two groups thence-
forward flourished side by side to the middle of the St. Loui.s group, when
the Platycrinidie became extinct; wiiile the Ile.xacrinidu) and their oU'whoot,
the Acrocrinidae, continued until the extinction of the Camerata.

We have not attempted to construct a genealogical tree for the Crinoids,
or a brunch of one for the Camerata, because such representations are
generally luisatisfactory, and in this case the tree would have to be con-
structed too much upon imagination. Besides, our task is an Innnbler one.
We have rather preferred to content ourselves in this respect with giving
the general facts which our investigations seem to pretty well establi.sh, and
such interpretation of them as appears to us reasonably consistent therewith.
Witiiin these limits we have hoped that our generalizations may help to
form a stable foundation upon which others may rai.se more ambitious
structures.

There is no doubt that the Crinoids, by reason of their great geological
range, and capacity for individual variation due to their complicated struc-
ture, offer one of the most inviting fields for demonstrating the principles of
evolution. Tiiey alTord a good illustration of the principle that individual
development fnids a parallel in a general way, in the phylogenetic history
of tiie group. But while recognizing this truth, and confirming it by the
many interesting proofs which our studies disclose, we must beware of ex-
pecting to fnid lineal succession, or of assuming that a form found flourishing
in any given epoch is neces.sariiy more highly organized than tho.se occur-
ring in previous epochs. The Palaeozoic Crinoids represent in a broad sen.se
the larval stages of recent Crinoids ; but there are many ca.sos in which the
tendency seems to have been one of retrogression instead of progression.
ILipiiicriiiii.s, with its closed pyramid of five orals, is probably the most primi-
tive type found in our collections, and yet it is a Devonian gcnu.s. The
great family of the Ichthyocrinidie, whose oral condition is substantially on
a par with that of many recent Crinoids, occuired abundantly in the Silurian,
it is also iini)ossible to tell, except perhaps in a very general way, which one
of a number of variations marked the line of succession ; or in other words
which was for the time being the racial characteristic carrying all others
along with it, even though many of them may seem more important. For

i I

SYSTEMATIC PART.

101

the snme ronson we cannot point out tlie exact coiisiin<,'uinity (if jrioiips
wliich are apparently related by one or more characters. For we liml that
when a type starts on a career of tlevelopincnt on a specialiyxMJ lino iiiid
runs its course, other characters for the time being subordinated tu it follow
in more or less parallel successions. So that it may come to pass that at
a certain time we find two types apparently belonging to dillerent lines of
development, which have reached a concurrent condition in some otlior
important character, and we cannot say through which of them the thread
of consanguinity has been carried. For instance, in the non-typical Camerata
we have the Phitycrinidie without an anal plate accompanied and succeeded
by the Ilexacrinidac, in which that plate is present. In the typical section
the Melocriniihv) are followed by the Batocrinida; and Actinocriniiliv in
similar succession. But (according to our pala'ontological record) the sym-
metric Platycrinidic appear at a somewhat later period than the symmetric
Melocrinidiu; — and as we do not find in the non-typical suction any s^-m-
metric predecessors of the Platycrinida\ we would bo inclined on this
ground to infer that they were derived from the Melocrinida?. But here
we are met by a greater difficulty, for this involves the illogical supposition
tiiat the PiaiycriuidiD — a family of the least development of the Camerate
type — are derived from one much more highly organized in that particidar
line.

The trouble is that all our generalizations arc necessarily based upon the
Crinoiils as they are represented in our dikhcidiis, and not upon the CViiioids
as they actually existed in geological time, which is a very dilTorent thing.
It is like trying to reconstruct a book from detached fragments of tin;
chapters, some of them written in hieroglyphics for whose decipherment the
key has not yet been found, ^\'e are accustomed to speak of the imjicr-
fection of the geological record, but it is doubtful if in our practical studies
wo always i)ear in mind what this really means. To say nothing of the
perio'ls antedating the Silurian, in which substantially all vestiges of lil'e arc
obliteraled by motamoiphisni ; of the accumulations of fossilitVrous strata
which have been destroyed by erosion during periods of elevation of the sea
bottom; of tlio strata which over three fifths of the earth are submerged
beneath the ocean ; of the great regions unexplored, or covered with ice.
snow, or snnd ; of the eciually extensive areas in which tiie fossililcrous
rocks of one formation ore buried under those of succeeding ones; — leaving
nil this out of con.sidcration, how much do we actually know of the life

168

THE CKINOIDEA. CAMEllATA OF NOUTII AMElilCA.

represented in the rocks accessible to «is? Nearly all the known Sihirlan
Crinoids come from the outcroppings of the strata at two localities in Europe,
and three or four in America. The Devonian exj. .<iu'es producing well
preserved specimens are even more limited. The Lower Carboniferous col-
lections are better and more widely distributed, but are insignilicant after
all. Take the Burlington and Keokuk lime-stone.x, wiiich in a few localities
have j)r()duce(l more Crinoids in number and .species than any other forma-
tion. They consi.st of several hundred feet of strata almost entirely composed
of the conuninuted remains of countless myriads of Crinoids — fragments
which are worthless to tha Palaeontologist. It is only rarely that a thin
layer is found in which the calcareous skeletons are preserved well enougli
for study; — little b sin- of limited extent, in which, during a period of tem-
porarily ([uiet waters, the Crinoids lived, died, and were imbedded at sudi-
cient depths to escape the detructive effects of .shore action. If the collector
hanpins to be present when one of these colonies is uncovered by the
quarrymeii, the specimens may be rescued for the benefit of Science. But
it is an oven chance that they will be buried in the del)ris of Jn: quarry,
biokea up for Ijallast, or walled up in the foundation of a l)ui'.]ing, and thus
h'> lost again. Out of the thousands of square miles in which these rocks lie
nciros; ilic surface, all the collections th.at have ever been made represent
" .i, ;,i(e imperfect gleanings of not more than a few acres. If it l)e sup-
poyi.d Ujat v>e get, even in this way, a fair rcfiie.sentation of the crinoidal
life of that period, the answer is that .ilmost every new discovery of " nests"
or "colonies" of good specimens brings to light new forms, and that species
or genera hitlierto very rare are often suddenly found within a limited space
quite abundantly. In the Upper Coal Measures, to judge from our books
and museums, one would suppose that Crinoids were well-nigh extinct.
Scarcel}' a dozen species are known, and most of them only by tlieir lower
calyx plates. Yet there are many beds in this formation which extend over
iiundreds of thousands of square miles from the Missouri Valley far into the
Rocky Mountains and tilted up along their flanks, which are completely
fdled with fragments of Crinoid.s. Suddenly the collectors at Kansas City,
who have studied t'.i^-so rocks for years, discover an abundant deposit of well
preserved specimens in a shale so .soft that a few minutes rain di.ssolvcs
them into unr eogiii/.abic fragments.

The importance of those observations, (('> a practical matter, is sufficiently
shown by the f.-^ct that the di.scove.-y of a single specimen may sometimes

SYSTEMATIC PAKT.

169

throw new light upon important questions, nnd require the undoing of
much previous work ; — us was iihistnvted in the ease of the disk of tiio
IchthyocriniduB, nnd by de Loriol's discovery of sninll infrahasals in two
Hpecies of Milkrici'intis, which made important changes in the classification
imperative.

DKFIXITION OF THE CKINOIDKA AND THEIU PKIMAKY DIVISIONS.

Class CUIN'OIDEA.

Ecliinoderms which during part or all of their life were attached to other
ol)jocts, eitiier l)y means of n stem or directly by the abactinnl side of tiic
calyx. The vi.scoral mass enclosed by a limestone test or calyx, constructed
of plates symmetrically arranged, and giving off well defiiitd, free arms
from the sides. Mouth directed upwards.

Crinoids in wliicli tlic arms aro free alMive the radials. Tlic top

joint tilt! youngpst in the stem Orilor Ixadv.nata.

A. l)isl{ composodot orals only. Ambulacra siibtogminal Subordt-r Larviformia.
15. Posterior siilo of the disk extended into a sac. Am-
bulacra suiira-tegminal Suborder Fistulata.

II.

Crinoids in wliioh the lower brachials take part in the dorsal cup.
All plates of the calyx united by close suture. Sloutli and
food-grooves closed. The top joint the youngest in the stem.

Order Cameuata.

III.

Crinoids in which the lower brachials arc incorporated into the
calyx either by lateral union witli each other, or by supple-
mentary plates, or a calcareous skin. All plates from the
radials up movable. Month and food-grooves exposed. The
toj; stem joint fused with the infrahasals, and not the youngest
joint of the stem Order Articulata.

A. Arms non-pinnulate Suborder Impinnata.

B. Arms pinnulate Suborder Pinnata.

170

THE CRINOIUKA CAMKKATA OK NOUTll AMKlilCA.

CAMKUATA.

Analytlt of the Fuintllei,

I. TvncAii Skctiov.

Lower brnclnals and interlxncliials furiniiig an important part of the
dorsal cup.

A. I.NTEKKADIALM ILL DKFINKD.

The lowiT plates of tlit; rays luoro or less completely separated
from those of other rays, ami from the primary iiitcrrailials,
by irregular supploinentary pieces. Aiuil int(<rrn(lius divided
by a row of conspicuous plates. (Dicyclio or Monocyclic) . Ueteocrinid.k.

B. Intehkadials well ukkined.

1. Dkyixic.

«. llddidh ill I'onfiirt ert'e/it lit the pnnteriiir shh' Tiiysanockinid.k.

/). liiidiidii separated all iiiiiiiiid Uuouockinid.k.

2. JIONOIYCLII'.

a. Rtidiah in cmitnet nil nrniiiiil.

Symmetry of the dorsal cup, if not strictly pentamorous,
disturbed by the introduction of anals between the
brachials only Melochinid.k.

Arms borne in eouipartment.s formed by partiticuis attached
to the tegmen. Dorsal cup perfectly pentamerous. I'lates
of calyx limited to a definite number Calyptocrinmd.t?.

b, liiidiiih in rnnliiet crcejit at the posteeior side, irhere the;/

are se/mrnted hij an anal jdate.

First anal plate heptagonal, followed by a second between
, two interbr.ichials Batociuxid.k.

First anal plate hexagonal, followed by two interbrachials
without II second anal. Arms branching from two main
trunks by alternate bifurcation Actixocrinid.i:.

II. Non-Tvpical Section.
Brachials and interbrachials but slightly reprcHented in the dorsal cup.

1. MOXOCYCI.IC.

a. liadiah in eoiilaet nil nrniind. Tinite jientnrjnnal .... 1'lATYCRINID.K.

b. Kadials sejiii rated at jiosterior side by an anal jilate. Ilnse

hexagonal.

Hasals directly followed by the radials ITexacrinid.k.

Hasals separated from radials by accessory pieces . . ArKocRiMD.i:.

2. DiCYCLIC.

Kadials in eontaet except at the posterior side Crotalocrinid.k.

THE CHINOIUEA CAMKUATA OF NOKTII AMEKICA.

171

GEOLOOICAL AND (lEOOllAI'HICAL DISTItlld'TION OV TIIK CAMEIUTA.

Optu flguiw iDtllcftt* Aawrlcan HiwcIm, tlioM niarkvtl ( } , KuropMo.
NlMHKlt OK Sl'KC'lKH.

OMiniL

i 2

Amtrlran.

r|i|>i>t('>iul MiMUiiireii

Si. l.cilliK

Cppor
: l.iiwor

Wiirmiw
Ki'ukiik .

lliirliiiRtciii <

KiiiilorliiHik
Wavorl)'
< 'liijiitt'iiii
ChciniiiiK .
IlaniiltiMt

I'piK'r llelili'rlii'rK
llrii<kaiiy . . .
I,imor llc'lilorljorg
Xiasam . .
llllilsnli Uivf'l-

'I'roiitou

TrncAt rou.

Moll*TTriCAL Kt>UI.

A|mn>xliiiiit«
Kun)|N>iiii

t^llllTttlvtlti.

Miimow

I Miiiiiitaiii I
I l.iiiin<tiiiiu I

I TppiT I

I Dcvuiiiaii I

Kiffl . .

(irniiwac'kn

( Diiillov I
) (iotlaiiil (

Tiitnl Ainerionn

Total Kiirojionii

219

Grand Total Speiiei

683

14(7)

{'■>)

80
2(1!1)

1 (.1)10(15)

.15

{7)(i:)

(34)

(I)

21(18)

(3)

8(48)

(19)

(52)

20.1

18 !
(ilO)

(20)

(4)

(20) (il)
2H

(2)

(24)

■1(5)

(.1.1)

(.13)

'f\

i:w

Sim III \^.

MT.

Ml i..'kui..k».iipvaiw «

ARIIKN-

«iini>r. I |>

HHtlltt.

4 i P 1 S

r ■ r

f 1

■5

; Si ?■ ?

i K ! a.

rH f

r
r

f g £

• : 1: r

1 1

^i|

c*5

•^

HftfHM-rliiMM*.
Kti<N|<irriulilM.

CulyitttK-rliililu.

lUttN-riiitdM*.

ArllnocriuldM.

—

•^

■

«bB

p4K

►

S '

—

«^

•

■-

t'roUlwriuldM.
llstyrrliiidM.

MnwrliiltlAf.
AirocrliiUlnc.

H^^

'■■

('ii|iri<wMKTliiUi.
MyrtilliH-riiiiii.

Mil|ll'KTllltlH.

HyiiiKiillKHTlnui.

AllnKtHrlliiiii.

I'lMHTlnill.

' "

HylNxrliiltUr.
HfUTorrliiUlae.

(.'iltillmrliiUlM.

Itt'lfiiiliorrliililM,

OimtrriN-niiililut.

Cyallnxrliii.Iiir.

►

— 1

— ,

...

1—

—

..^

■n

1 " 1

■

1 '«>(«• rIorrliililM.
Rnrrini'lnr.

—

"•■

«ii;^

)
1

Aiitylnt'rinltliic.

ZdlihorrlnuB '.'

^ —

^^^^

—

IililliyocrinlilM.

H
>

B. Dincrij)tii'e.
nr/rKOCRIXIl).K W. and Sp. (1885).

ThB LOWKR PLATKS 111' TIIK IIAYH MOrtK oil I.KSH C'OMI'LCTKLY HEPAUATEt) FUOM THOSE
OK OTIIEIl HAVS, AM) EUciM TIIE PIIIMAIIV INTKIiriAIII Al.H, nV lllllElil'LAIl HUPPLK-
MKNTAKV PIECES. ANAL IN TEllllAIUrs IHViDEI) IIY A VKIITUAL ItOW OF CdN.SPICII-
POUS PLATES. (DltyCLIC Oil MoNOlVt Lie. )

Aimh/'Oi "J'flir Oiiiirn,
Arma uulserlal.

"■ Il'dllldh Hf/i ill iii'iiiiikI.

J)iii/i'/!i: i,iip,iHiil» 5. ('oluiiin |H'iit;iiigiilir RKTEoruiNM's.

Muiiiii\i/i'/ir. Ilasiils l. Cdluinii siniaro Xemukim m.

A. Jiiitlltt/i nr/ittrntiil niilij nt iiiiiit »!i/i:

Monoei/rllc. HiiNals ">. ('Dlumii obscurt'ly ju'iitangular Ta.naocui.vun.

Gfnfdijlfal mill (Jioifrn/i/uriil Dlslrlliiittoit
Number of known apedea. Only known In America.

Formation.

neTKorniMii^.

AmiTiiiui.

lliulsuii liivur.

Hcteoorimis.

Xciiooriiius.
2

Tanaocrinus.

'rreiitoii.

Total »p«Im ... 7

Rcmtii'ls. — Tliis family was e.ttnl)lislie(l to roocive a littlo group of rx)\ver
Silurian Crinoids, (li.xtitijfiiislii'd from all otiicr known forms by the irregulr.r-
ity and ab.sonce of definite arrangement in the intenadial plates, caused by
tije intercalation of minute supplementary pieces. These small pieces were

i ^

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TEST TARGET (MT-3)

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4^'

174

THE CKINOIDKA CAMEBATA OF NORTH AMERICA.

Oaiiio^

introduced in the growing Crinoid in great numbers among the primary
interradials and interdistichals, and between these and the basals, radials,
and brachials. The interrndial and interdistichal spaces throughout this
group are greatly depressed, and the plates succeeding the radials folded
into conspicuous ridges. This structure, combined with the more or less
rudimentary character of the interposed plates, is so unique and remarkable,

that all other characters, some of
which in other groups are charac-
teristic of very distinct families,
appear to be subordinated to it,
and we are compelled to unite
under this family both monocy-
clic and dioyclic forms; those in
which the radials are all sepa-
rated, and those in which they
are in lateral contact at four sides.
We think that few, after seeing
a large number of specimens, will
doubt the propriety of this course ;
for the structure in question pro-
duces a habitus so distinct and
predominant, that it is only by
means of these characters that the
three genera of this family can be separated.

In our classification of 1885,* we proposed the genus Canistrocrinus upon
two species, which according to the descriptions differed from all genera
previously known. In defining the genus we relied upon the correctness of
the figures ; but these have proved to be mi.sleading in some very important
points, and we are compelled to withdraw it. As to "Canistrocrinus" liichard-
soni {Glijptocrimis liichardsoni Wetherby). we are now convinced that it is
a Ghjidocrimis, and identical with Gl///)focriiius siibglohosiis Meek. It has well
defined interradials, aiul the anal plate rests vpon the radials, and not between
them. The other species, ^'Canistrocrinus" Pattcrsoni {Gli/ptocrimis Puttersoni
S. A. Miller), may also prove to be a Oli/ptocrinus. The type specimens,
which Mr. Miller was kind enough to send us for comparison, are not in
a condition to make out the structure satisfactorily, being covered to a large

Fig. 0. Reteocriiiiis Oiiealli.

Revision, Part III., p.

reteocrinid.t:.

175

extent by hard matrix; and we are unable to say at present to what genu.s
they belong.

S. A. Miller, in his arrangement of the Lower Silurian Camerata in
1883,* united lidcocnnus and Xeiiocriiiiis with Arc/iavcriniis, CnjHtlucrliiiis,
Gli/ptastcr, Gli/ptocrimis, and Lampterocriims in one fiiniily, under the " Gi^pto-
crinidae." It is not clear to us upon what this classification wiu based, since
the author did not discriminate between the presence or absence of infra-
basals as a family distinction, nor between a regular or irregular arrange-
ment of the interradials ; nor did he give attention to the structure of the
anal side, upon which most writers, and Miller himself, have relied for
excellent family characters. In a later paper on Gli/ptocrimis and allied
forms,t he states that the presence or ab,sence of " .subradial " plates, the
presence or absence of " secondary radials," the structure and form of the
column, and the presence or absence of a " proboscis," are the principal
characters upon which " the genera of this special group " have to be separ-
ated. All of these rules are in a greater or less degree infringed by Miller
himself. His " Gl^piocrintis " parvus has infrabasals ; his ^'Ghjptocn'ntts Forn-
shelli, a pentangular stem instead of round as in the typical species. A " pro-
boscis," such as occurs among the Actniocrinida?, does not exist at all in this
group, or at least has not been observed. Neither do we find that the
proximal distichals are ever free arm plates, as Miller claims to be the case
m " Pi/cnocrimmy The specimens which he refers to this genus, and which
he kindly sent us for comparison, have from one to two interdistichals, and
necessarily had " secondary radials."

In Miller's classification of 1889, | the " Glyptocrinidoe " embrace the
genera Archccocnnus, G/>/ptocii'niis, Compsoeriniis, Pi/cmcnims, and Schkocriims,
which, as we think, are representatives of almost as many families. He
there makes Xcnocrlnus the type of a distinct family, refers Glyptasfcr and
Laniptcrocrinits to the Glyptasteridte, and places Gauroeriiiiis, Ihieocrinvs,
Raphanocrinus, and Thi/samcrimis under Gaurocrinidae.

The Reteocrini<la} are restricted to America, where only seven species
have been discovered.

I •■

I !>

• Amer. Palffioz. Foss. (od. 2), p. 278.

t Dec, 1883; Journ. Cinciii. Soc. Xat. Hist., pp. 218-219.

X North Amer. Geol. mid Pnlreoiit., pp. 211 to 215.

176

THE CRINOIDEA CAMERATA OK NORTH AMERICA.

RETEOCRINUS Uilli.vgs.

1859. E. Billings ; Geol. Rep. Caiindn, Decade VI., p. 03.

1S81. \V. niul Sp. ; Ucvision I'ulieocr., I'liit 11., p. 101 (Proceed. Aend. Nnt. Sci. Philii., p. 305).

1883. P. II. Caiu-extei< j Pjil. Tniiis. Uo.vul Soc. (Pail III.), pp. 92U-932.

1883. W. and Sp. ; ' mer. Jourii. Sci. and Arts, Vol. XXV., pp. 255-208.

1883. S. A. MiLLE , ibid., pp. 105 to 113.

1885. W. and Sp. ; Revision Puteocr., Part III., p. 87 (Proceed. Acad. Nut. Sci. Pliiln., p. 309).

18S9. S. A. Miller; North Anicr. Geol. and Palroont., p. 277.

Svn. UtyplocrtHus (m part)— Hall; 1872, 2itb Hep. N. York State Cab. Kat. lli»t., \>. 200, Plate
5, Pigs. 18 & 19.

Svn. Glyptocrinm (in part) — Wetiieuhy ; J.inrn. Ciiiein. Soc. Nat. lli.st., Vol. II., Plate 10, Fig. 1.

Sj'i. Gli/ptocrinua (m part) — S. A. Miller; 1881, Journ. Ciiieiu. Soc. Nat. Hist., Vol. IV, p. 83,
Plate 1, Fig. 5, and 1881, il)id. Vol. VI., p. 227.

Syu. Oaurocrinus {m part) — S. A. Miller; 1883, ibid. Vol. VI., pp. 228, 229.

Calyx obconical, its .symmetry decidetJly bilateral, interradial and inter-
distichal spaces profoundly depressed ; the plates all along the rays distinctly
folded, so as to produce strong, rounded ridges upon their outer surfaces,
and deep grooves at the inner. The ridges branch upon the axillaries, and
follow the distichals to the arm,^ Other branches proceed from the middle
of ihe radials to adjoinin;.^ basals.

Infrabasals five, variable in size ; sometimes barely protruding beyond
the column. Basals five, large, protuberant, hexagonid, the upper angles
truncated, and the ends somewhat inflected to meet the deep depressions of
the interrad'al spaces. Eadials separated all around, sharply angular at the
lower faces. Costals two to three ; their axillaries clo,sely resembling the
radials, but angular above instead of below. Distichals numerous ; all, or
nearly all of them, take part in the calyx, and the upper ones retain the
form of free arm joints. The proximal pinnule occurs on the second dis-
tichal. Arms ten at their origin, but generally bifurcating; composed of
rectangular or slightly cuneate pieces. The interradial and interdistichal
spaces filled by primary and secondary plates ; the latter very minute, inde-
finitely arranged, ill-formed, and interposed between the others, and along
the sides of the ba.sals, radials, and brachials. The anal interradius wider, and
longitudinally divided into two equal parts by a row of very prominent anal
plates, which lie in a straight line from the basals to the anal opening.
Ventral disk depressed convex, composed throughout of minute irregular
pieces, which form a continuation from the interbrachials and interdistichals.
Ambulacra subtegminal; Anal opening excentric, at the top of a small
protuberance. •

Column large, pentagonal ; the axial canal of medium size.

Ill

RETEOCUIXID^E.

■ ( t

Distribution. — Age of the Trenton and HudHon river groups. Restricted
to America.

Remarks. — According to Billings, the calyx of Hdcocriims stclluris, the
type of the genus, consists of a reticulated skeleton, composed of incomplete
or rudimentary plates, each consisting of a central nucleus, with three to
five stout processes radiating from it. Of such plates he describes three
rings of five each, corresponding in position with infrabasals, basals, and
radials of other Crinoids, and he states that the genus in general structure
agrees with Cyathocritms, Dcndrocrinns, and allied forms.

It would seem at first sight that this description docs not apply to
" Glypiocrinus " Oncalli and the other species that have been referred to this
genus, as they have numerous interbrachials and interdistichals Avhich Bil-
lings failed to notice. These plates, however, are actually present in the
type specimens, having been exposed by additional cleaning. Looking at
Reteocrinus Oncalli in its usual preservation, with its deep intorradial areas
covered by matrix, it corresponds well with the original description. The
specimens in that state seem to have but three rings of plates in the calyx,
and free brachials from the radials up.

Miller refers to Reteocrinus only Billings' two typical species, placing the
other three under Gmirocrinus. We cannot discover any ground for generic
separation of the Ohio and Canada species. It is true Reteocrinus stclluris has
a third costal, but Miller himself did not attach much importance to this
character, for he grouped Reteocrinus Jimhriatus with but two costals, along
with R. stelluris, which has three.

In amending the genus Reteocrinus in 1881,* we referred to it the follow-
ing species : Gli/ptocnmis Bacri Meek, Glyptocrinus cognatus Miller, Reteocrimis
Jimbriatus Billings, Reteocrinus gracilis Wetherby, Glgptoerimts Oncalli Hall,
Ghfptocrinus Richardsoni Wetherby, and Reteocrinus stellaris Billings. We
afterwards f withdrew Reteocrinus Buei-i, which we found to be a Xenocrinus,
and Reteocrinus Richardsoni, which we placed under Canistrocrinus ; and we
added Gaurocrinus magnijieus S. A. Miller. Reteocrinus cognatus is probably
a large R. Oncalli, and R. gracilis a synonym of Ptychocrinus parvus.

* Revision, Part II., p. 102.
t Hcvisiou, Part III., p. 96.

178

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

ReteocrinUB StellariS Billings.
Plate IX. Fiffs. 3a, b, c.

1830. E. BiLLiNcs; Gen!. Ufp. Ciiniuk, Decade IV., p. 61, Pluto 9, Figs. 4a, b, e.

1877. S. A. MiLLEli; Ciilal. Aiiier. i'ulicoz. Foss., p. 90.

1881. W. and Sp. llevisioii Pala^ocr., Part IT., p. 193.

1889. S. A. Millek; North Aiiier. Geology aiid ralieoiit., p. 277.

Calyx proportionally larger than in any other species of the genus,
embracing all the distiohals and portions of the palmars.

Infrabasals and basals uuiisually large ; the former projecting distinctly
beyond the column, each plate forming a good-sized pentagon. Basals
heptagonal, slihtly truncated and folded inward at the upper ends; four
of them of equal size, that facing the anal side larger, and the truncation
wider. The surface of the basals is marked by prominent keel-like pro-
cesses, meeting in the centre of the plates ; one of these proceeds to the
radials and costals, two others to the infrabasals. At the sides of the pro-
cesses there ai'e deep depressions, five of them in a radial direction, formed
l)y the inflection of the lower angles of the radials and the upper lateral
margins of the basals; five others, somewhat smaller, triangular in outline
and interradial, by the basals and infrabasals. The posterior basal, at its
upper face, has three ridges instead of two, of which the median one is
continuous with that formed by the anal plates. Radials about one half
longer than the co.stals. Costals three ; the first and second quani-an-
gular, the third pentangular. Distichals five to seven or more, decreas-
ing in width upwards, the upper ones taking the form of free arm plates.
Above the distichals are two more divisions, but only a few of the palmars
take part in the calyx. The arms are extremely short, and taper rapidly ;
they are composed of rather long, quadrangular joints. Interbrachial and
interdistichal areas profo'mdly depressed, paved by numerous irregularly
arranged and ill-formed pieces, with a slightly stellate surface. Anal in-
terradiu.s twice as wide as the others; divided by a longitudinal row of anal
plates, somewhat narrower than the costals, but resembling them in height
and curvature. Construction of tegmen, position of anal opening, and
arrangement of pinnules unknown. Column obscurely pentangular, at the
upper end composed of very thin, knife-like joints.

— Horizon and Localiti/. — Trenton limestone ; City of Ottawa, Ontario,
Canada.

Our figures were made from the ti/pe specimens in the Canada Survey
Museum.

RETEOCRIMD.K.

179

Reteoorinus flmbriatus Uillinus.
Plate IX. Fig. 4.

1859. E, Billings; Gcol. Rep. Caiiiuln, Dec. IV. p. 05, Plato 9, Fig. 3.

1877. S. A. Miller; C'lital. Aincr. I'alieoz. Foss., p. DO.

18S1. W. and Sp.i Uevisioii riiljcocr. I'art U., p. 193.

18S3. W. niul Sr. ; Amcr. Joiiru. Sei., Veil. XXV., j). Sfifi.

1889. 8. A. Miller; Nurtli Aiiuir. Gcol. & I'alicout., \i. 277.

A small species of the type of Relcocrhnis maz/iii/ciis. Dor.<!nl cup to the
top of the costals subpyramidal ; .slightly more spreading from there upward.
The plates forming the rays rounded, and elevated conspicuously above the
interradial spaces.

Infrabasals Ptnall, their upper angles and the adjoining lower angles
of the basals depressed into small pits surrounding the column. Similar
pits are formed in a radial direction by the basals and lower margins of the
radials. Costals two, as large as the radials. Distichals eight or more,
narrower than the costals, the lower one longer than wide, the length of the
succeeding ones gradually decreasing upwards. Six of them apparently are
included in the calyx, the others free arm plates. The upper distichal is
axillary, and .supports two arm.", one of which remains simple, while the other
bifurcates once more. The arms decrease but little in size ; they are cylin-
drical, composed of rather long pieces, quadrangular in outline, with nearly
parallel faces. Pinnules decidedly tapering to their distal ends. Inter-
radial spaces deep, paved by a large number of very small, slightly convex
pieces, without definite arrangement. There is generally but one plate in
contact with the basals, but its outlines are very irregular, and that is still
more the case with the succeeding plates, and the numerous interdistichals.
Form of ventral disk, and construction of the anal sjde unknown. Column
at its upper end sharply pentagonal, with re-entering angles.

Horizon and Lomliti/. — Hudson River group ; Charleton Point ; Anticosti.
Ti/jK in the Canada Survey Museum.

I i

! i

Beteocrinus Nealli (Hall).

Plate IX. Figs. la-f.

1872. Qlyptocrinui Nealli — Hall ; S-tth Rep. N. Y. State Cab. Nat. Hist , p. 206, Plate 5, Figs. 18 & 19.

1S73. Gli/ptocrinus Onealli — Meek; Geol. Rep. Oliio, Palrcniit., I,, p. 34, Plate 2, Figs. 3ff, b, c.

1881. Rcleocrinus Onealli — W. and Sp.; Revision Palicncr., Part IT., p. 193.

1S82. Glyptocriiius Nealli — S. A. Miller; Jouni. Ciiiein. See. Nat. Hist., Vol. V., p. 37.

1883. Ke/eorrimia Oiienlli — 'W. and Sp. ; Amer, Jmirn. Sei., Vol. XXV., p. 2fiO.

1883. Gaurocrinm Nealli — S. A. Millea; Jouru. Ciucin. Soc. Nat. Hist., p. 229.

! i

.]t

180 TIIK CUINOIDKA CAJIhRATA OF NORTH AMERICA.

1885. Ri'IrorriiiuH n,i,;i/li—W. mid Sr. ; Hcvisi )n Piilu'orr., I'nrt III., |i. 80.
18S9. (luurofriiius Xeulli — S. A. M11.1.BU; Ncrtli Aiiicr. tleol. & I'liliuoiit., p. 2-17.

S^il. Glj/iilcn'i-iiiiiH cwjiMtna — S. A. M'LLEli; ISbl, Ciiiciii. Juurii. Nut. llist., Vol. IV., p. 75, I'liite
1, Fih'S' 5. 5'''

Syn. Gdiirucriiiun cogniitus — S. A. Mii.lkr; 18S1, Ciueiii. Joiirii. Nat. llist.. Vol. VI., p. 22'J.

Syii. Itilruvriiimi co(jmUiis — \V. 1111 i Si', j 1881, UcvisiuU I'ula'ocr., i'liit 11., p. 11)3.

Calyx obconical ; intorrad.ivl and intoraxillary spaces deeply depressed,
producing a pentagonal oiitiinu below the distichuls, and decogonal above
tlieni.

Infrabasals small, but projecting beyond the column. Basals large, their
lateral margins deeply impressed, forming an elongate pit in which the upper
angles of the infrabasals and the lowei' angles of the radials are involved.
The radials, costals, and lower distichals are folded abruptly inward, their
sides extending to the bottom of the interradial and interdistichal spaces,
leaving a very narrow surface expo.sed, not more than the width of the
arms. Distichals ten to fourteen, of which six to seven are located within
the calyx walls, the others free. Of the fixed plates, the three or four
proximal ones are larger and especially longer than the succeeding ones,
which are nearly as short as the free plates. A second bifurcation takes
place in the free arms, giving twenty arms to the species. Arms long,
cylindrical, gradually tapering, and composed of short, wedge-formed pieces.
The first pinnule, which is given off from the second disticlml, is moriB erect,
and considerably stouter than any of the rest. The second pinnule, which
occurs on the opposite side at the fourth plate (the third bears no pinnule),
is smaller than the first, but larger than the third, which is of the ordinary
size. The three proximal pinnules are incorporated into the calyx, the
succeeding ones free. Interbrachials and interdistichals very numerous,
exceedingly small, and of very irregular form and size ; the marginal pieces,
as a rule, being smaller than the others. Anal side marked by a conspicuous
median ridge. Tegmen low-hemispherical, decagonal in outline ; the spaces
overlying the food grooves .slightly elevated. Anal opening excentric, almost
marginal, placed in the middle of a small protuberance. Column pentan-
gular, the outer faces slightly impressed ; composed alternately of thin and
somewhat thicker plates, the latter protruding considerably beyond the
others.

Horhon and LocnlHff. — Upper part of the Hudson River group ; Warren
Co., 0. ; rare at Cinciniiati,

Tjipc specimen formerly in the collection of J. Kelley O'Neall, now in the
collection of Wachsmuth and Springer.

i i. '

hiij

■

;

RKTEOCRIXID.E.

181

Rcmarh. — The peculiarity that the «iiialloMt intcnndials are marginal
and lie next to the rudials and bawls, instead of diininisliing in si/.e upward,
as is usually the case, leads to the conclusion that these plates were intro-
duced between some of the older pieces, and are secondary plates which
cannot be homologized with the primary interradials of the Actinocrinida>.
The structure is well shown in our ligure, Plate JX. Fig. 1/, which represents
the inner floor of a fine specimen in which the arrangement of tiie primary
interradials is very little disturbed, being 1, 2, .3, all of them isolated and
surrounded by small supplementary pieces. We shall di.>icuss this subject
further in our remarks upon Xinocnints jiciiwi//iis and A', liiuri.

We have had no opportunity to examine the type ,<[)ecimen of Gh/ptncriiws
mguatm S. A. Miller, in the collection of Dr. R. M. Byrnes of Cincinnati, but
from the description and the figure we are strongly inclined to regard it as
a large specimen of liclcocviims Oiiailli, and not a variety of that species, as
suggested by Miller.

Beteocrinus magnificus (Miller).
Plafe IX., Fiff. 2.

1SS3. Gfiurom'iiiia tnagnijieua — S. A. Miller; Journ. Ciiiciii. Soc, Nnt. Hist., Vol. V[., p. 2liO, Plate 11,

FiR. 2.
1S''5. Reteocriiiiis mngiiijtrus — W. ntul Sr. ; Revision Palipocr., I'lirt III., p. 91.
ISSl). Gaiirocriima iiiat/niJii-Hn — S. A. Miller; North Amcr. Gcol. niid riiliiunt., p. 217.

A larger species than Rdcocriims OncalU. Calyx subovoid ; section pen-
tangular; the interradial and interdistichal spaces deeply depressed; the
radial ridges broad, flattened at their upper faces, and branching from the
middle of the radials to adjoining basals.

Infrabasals small, almost covered by the column. Basals of medium size,
somewhat convex, their upper ends inflected toward the impressed inter-
radial areas, the interbasal suture lines deeply grooved, and forming with
the lower end of the radials a lozo'igo-shaped concavity. Radijils a little
narrower at the top than at the boi oi"; Costals two, narrow, as long as the
radials, and without lateral extensions. Distichals very variable in number,
from two to fifteen, the three or four lower ones almost as large as the
costals. When there are but two distichals, which is apparently exceptional,
there is an additional bifurcation in the calyx ; while in the other cases there
is only one more bifurcation, which takes place in the free arms, and the
second distichals support a very large pinnule. Arms stout, rounded and

! 1

182

THE CKINOIDEA CAMEUATA OF NOltTII AMKllICA.

coiistnicted of extremely slioit, Hlightly convex, cimento pieces. Pinnule»
composed of live or more joints ; long, slender, and not in liiterul contact.
The first pinnule is borne upon tlie second distichnl, iibove which every
joint, the nxilinries excepted, is pinnule-benring. Interradiiil luciis more
substantial than in the preceding species, the plates stouter, and the median
portions rather convex than concave. Each area contains from twenty-five
to thirty pieces, some larger than others, of all possible shapes, and indis-
criminately arranged. The construction of the anal side is not known. The
interdistichal areas apparently extend to the top of the fifth distichals, are
comparatively flat, and compo.sed of similar pieces to those of the intcrradial
spaces. Construction of disk and anus unknown. Column near the calyx
distinctly pentangular ; the nodal joints longer, slightly projecting and
rounded at the margin ; the internodal ones shorter, and provided with
sharp edges.

ILn-lziin ami Locality. — Hudson River group, Warren Co., Ohio.

The tiipc specimen now in the collection of Wachsmuth and Springer.

XBNOCRINUS S. A. iriLLEH.

1881. S. A. Miller; Journ. Ciiicin. Soc. Nnt. Hist., Vol. IV., p. 72.

1881. W. and Sp. ; Uovisiou I'nliroer., rnri II., p. 184.

1883. W. and Sp. ; Anicr. Journ. Sci., Vol. XXV., p. 260.

1884. r. II. Caiipkxteb j I'liilos. Trans. Hoyal Soc, Part III., p. 930.
18S5. W. and Sp. ; Kcvision Talffiocr., Part III., )i. 94.

1885. W. and Sp. ; Proceed. Acad. Kat. Sci. Pliila., p. 317.
1889. 8. A. MiLLEii; North Ainer. Gcol. and Pnkont., p. 287.

Xcmcrinm resembles Rdeocrinvs, but is without infrabasals. Bofals four,
forming a low cup, which is decagonal at the upper end ; five of its sides
supporting the five radials, the five others the interradial and anal plates.
This arrangement gives to the basals, owing to their abnormal number, a
very irregidar form, no two of the plates being alike.
Radials generally a little larger than the costals. Costals
two, the sides bending abruptly inward and forming highly
elevated ridges ; the distichals to about the fiflh or eighth
plate form part of the calyx. The lower of the.se plates
are larger, and more or less resenjble the costals, while the
upper ones are more like free arm plates. Arms ten,
simple, rather stout; composed of very short cuneiform
pieces, which at the tips of the arms slightly interlock.

I'IG. 7.

RKTEOCRINID^E.

183

Interradial npacos deeply iinpresHecl ; composed of numcroim iiiiniito
pieces without definite nnungenient ; they rest upon the baoal.s, Mepiimting
the rays from tiieir bases up. Anal interradius wider tliim tlie four others;
divided longitudinally by a row of folded plates, which like the radials have
a prominent ridge upon the outer surface, and a groove at the inner lloor.
The ridge ends in a small protuberance containing the anal opening, which
points upwards. Interdistichal spaces also deeply depressed, and filled by
irregular, minute plates, which like those between the main rays pass imper-
ceptibly into the disk. Ventral disk comparatively flat, composed through-
out of very small pieces ; orals being unrepresented, and the disk ambulacra
subtegminal.

Column quadrangular, with pentangular central canal, the angles of
which are directed interradially,

D'lsl ribiitlon. — Tiiis genus, so far as known, is limited to the upper part
of tlie Hudson River group of Ohio.

Type. — Xcnocrinus jieiiicilliis Miller.

licmarh. — We place i.i this genus Gli/ptocrimis Daeri Meek, which, ns we
have discovered, has a quadrangular stem and four basals. Xmocrinua is the
only monocyclic genus in which interradials come in contact with the basals
at all sides, but we doubt if its interradials separated the rays as completely
as in the case of the Rhodocrinidoo. In a specimen of X. Bacri from the
collection of Mr, I. II. Harris (Plato IX. Fig. 5c), in which portions of the
inner floor are exposed, it is plainly seen that the lower ends of adjoining
radials touch each other, and after a careful study of the structure we are
inclined to believe that the small accessory pieces, which seem to separate
the radials, rest upon the lower outer margins of the plates, and not between
the plates.

Xenoorinus penioillus ^[illkr.
Plate IX. Figs. Ga, b.

19S1. S. A. Miller; Journ. Cinciii. Soc. Nat. Hist, Vol. IV., p. 72, Pinto 1, Fig. 3j nnd ibid., p. 170,

riiite t, Fig. 6.
1SS3. W. and Sr. ; Amor. Joiim. of Sci., Vol. XXV., p. 200, nnd 1S83, Kcviaioa Pnlffiocr. Part III.,

p. 90.

A small species. Calyx elongate, once and a half as high as wide, ob-
conical at the lower end, then rising almost vertically to the free arms ; the
radials and brachials highly elevated, folded lengthwise with rounded back ;
the interradial spaces deeply impressed, the plates somewhat nodose.

184

TlIK CUIXOIDKA CAMKHATA OK NOUTU AMKURA.

Diisiils ioriiiiii}^ 11 siiijill hii.siii, wliicli iit tliu Ituttuiii irt Migtilly i>.\ciiV(iti:'<1
for thu i'fC('[itioii (»r tliu culuiiui. UmliulM iiiid cu.^tiiln ol' iioiuly ciiiiiil nI/.u,
<ino tliinl l()iij,'i'r tliiiii wido, tlieir liitonil I'licu!* (lisliiictly coiivux, ho as to j;ivt'
to tlio hIiIch a sort of t^ciillopcil uppoiinuicu. DiHliclmU freu from tlic iiiiitli
or tenth pliitu; lliu four or livu lower ouum uloiigiilu, in I'onn iiiiil hI/m ru-
Honiljl'mj,' llio fostiils ; tin- Miicct'cdinj; oni'M graclmilly decreusing in longtli;
iiml tlio iippiT Olios us short as the IVuo arm phiti's. Anns ten, appiireiiily
short; coiii[)i)SL'd of low ciinoato pieces with somewhat ronndod outer e<lges.
Tlio (irst pinmilo starts from the second distichal ; it is stronger than the
others, and, liiio the throe or lour succeeding ones, incorporated into the
calyx. The free pinnules are more slender and longer ; they consist of six
to seven joints, twice as long as wido. Interradial spaces deepening toward
the middle, and deepest in their upper portions. They are composed of
a very largo numher of miiuito pieces, are irroguhirly arranged, tuberculous
and slightly stellate. Similar plates till up the spaces between the disticlials.
Anal interradiiis wider; divided by a longitudinal row of llfteon or more
largo anal plates, whiiih in form and size resemble the lower brachials, and
their sides are .scalloped in a similar manner. The row termiiiiites in a small
protuberance near the margin of the disk, which contains the anal opening.
Ventral disk hemispherical, pentangular in outline, the surface slightly ele-
vated in the direction of the food grooves; compo.sed of hundreds of minute
pieces ; the ambulacra subtegminal. Column quadrangular, its sides dis-
tinctly concave. Axial canal pentangular.

IlorLon tinil Loca/i///. — Hudson River group ; Warren Co., 0.

T///ICIS in the collection of Mr. I. II. Harris of Waynesville, O.

licmurhs. — Among the specimens examined, there is a very interesting
small Olio, in which the interradials do not touch the basals. In this speci-
men it is most romarkablo how the interradials vary in size. Three of them
are tolerably large, but they are isolated from each other, and from the
radials and basals, by numerous small, almost microscopic pieces, smaller
than the corresponding plates in more mature specimens. The larger plates
occupy approximately the position of the first and second row of inter-
brachials in the ActinocrinidaD, and undoubtedly represent them, being
pushed out of position by the development and intercalation of supidemen-
tary pieces.

RKTK()C'niNIIl-K.

186

XenoorlDui Baeri (Mkk.k).
I'lah IX. Fiijx. 6ii-il.

187*. Olyp/'HriuHi Ihifri — Mhtiii Ainrr. .Inurii, ^<l■i , Vul III. (Hi! »cr.), p. 2(10.

l><7;i. Ill,1lilni-riii«» lt,(,;-i — Mkkk; (i((il l(r|i. OIiIm, I'liliruiil., Vol. I., |i, ;)7, I'lalc i. Ki({. 1.

INSO, llli/iilw,-inH> l,ii,;i — .S. A. .Mll.l.KHi Jciiirii. Ciiioia Siv Nul lli^l.. V.jI. III., I'liiti' 7, Fig. t.

ISSl. H'/>f,,-nHMt llihi-i— \V. iiimI Mi-. ; l(i'n>luii I'mIiimut,, I'ihI II., |> IICI.

|s»;», H'li'fH-riHun limn — \V. ami Sf, ; Aiiicr .Icpiini. Sii, Vol. XXV , |i im.

l^S:i. li/y/j/>ir,-i,iHt/„i';-i—!*. A. .Mll.l.Mt; Jnuni. Cliiiih. Scic. Nal. Iliil,, Vul. IV., p, ij^ii.

1SS3. .\';wn„u.i Hi„;i — \V. and Si'. ; ItcvUioii I'alaiMr , Tail III,, |i IMl

1.S81I. Xfiiiifi-iiiu^ /iiiiui — S. A. Mii.i.Kii; Ni)rtli Aiiicr. (Ji'iilug^ ami ruln'mil., |>. itS.

Dorsal oii|) iiiglior llmii widu ; Hu))uvui(l ; dupreH.scd at tliu iiiterriulial
Mpnci'M, Imt not ho imicli no as in X.piniciUux; cvohh-hwX'mw pt'Mlanjfiilar.

lia.'^ulH Hiiiall, only tliuir iippor aiigloM visiblu in a h'uIo view. KadiaU and
coMtals elongati'. Ibrined into conspicuous rounded riilgcs, wliicii occupy
almost tlio entire widtli of tlie plates. Disticlials free from tiie lil'lh or si.\tli
jtlato ; the two proximal ones as large as the costals, the third somewhat
shorter, and tlie upper one.s but little longer than the free plates. Arms
ten, simple, long, rather Htout; composed of very siiort, transverse joints,
with slightly convex outer faces. The lower arm joints rectangidar, followed
by cimcate pieces, which slightly interlock. Interradial areas dee|)est iu the
middle; composed of numerous very small, convex pieces, with a somewhat
corrugated surface. Anal side dividctl by a longi i;dinal row of anal plates,
shaped like the radials and costals. Ventral disk low-hemispherical ; plates
very minute; the po.sition of tho anus uidtnown. Column quadrangular,
with obtuse angles; the joints extentled outward into hmg knife-like edges.

Ilorl.viiii ioiil LncaUl;/. — Hudson River group ; Warren Co,. 0., and Uich-
mond, Ind.

Tiu' specimens figured are from the Collection of Wachsnuith and
Springer, and that of I, H. Harris, Esq., of Waynesville, 0.

TANAOCRINUa (n-v. gen.), W. and Sp.
(Tdiiid?. slt'iidpr; KpiVoi'. a lily).

Resembling IMcocfinvs, but without Infrabasals, and the radials in laterjvl
contact except at anal side. Symmetry decidedly bilateral. Arms long and
slender.

Basals small ; the posterior one truncated at the upper end, and followed
by a large anal plate. Costals two, narrower than the radials, and folded

186

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

■ I.

■ 1

: I

•1 I

like arm plates. Distichals numerous, for the most pnrt incorporated into
the calyx. Arms branching once or twice beyond the calyx.

Interradial and interdistichal areas deeply depressed, filled by numerous
minute, irregular pieces. Anal side wider than the other four, divided by
a median longitudinal row of large anal plates, folded like the costals.
Structure of the disk and position of the anus unknown. Column round
or obscurely pentagonal.

Distribution, etc. — Restricted to the Hudson River group of America.

T//2}e of the genus : — Tanaocrinus typus W. and Sp,

Tanaoorinus typus (nov. spec), W. and Sp.
Plaie IX. Fi(js 7a, b, c.

A small and slender .species. Calyx elongate; broadly truncate at the
lower end ; plates without ornamentation.

Basals five, plainly visible in a side view ; forming a short cup, which is
slightly excavated at the bottom. The upper laces in four of the plates sharply
angular, that of the posterior side narrowly truncate. Radials the largest
plates of the calyx, much narrower at the top than at the bottom, rounded
at the lower face. They are connected laterally, forming a wide and deep
notch for the reception of the interradials, except at the anal side where the
first anal plate rests directly upon the basals. Costals two, as long as the
radials but narrower; folded and elevated in the middle, the lateral margins
on a level with the interradials. Distichals seven to eight; all, or nearly
all of them, incorporated into the calyx ; the lower ones as long as the costals,
but a little narrower; the upper ones gradually growing .shorter, and taking
the form of free arm joints. Palmars twelve or more, all of them free. The
arms branch two or three times ; they are long, cylindrical, and taper gradu-
ally to the tips, where they become very delicate and thread-like. They are
composed of short, cuneate pieces which do not interlock. The first pinnule
is given off from tlie second distichal ; it is more than twice as large as any
of the others, and it, as well as the three or four succeeding ones, is enclosed
in the calyx. Interradial and interdistichal spaces deeply depressed, the
plates very small and without definite arrangement. Anal side twice as wide
as the other four, and divided longitudinally by an anal ridge of five to six
large plates, which closely resemble the radials and costals. The first anal
plate, which rests upon the basals, is nearly as large as the radials, and like

I "

RETEOCRINID^E.

187

them narrower above than below ; the succeeding ones are a little smaller
than the costals. Ventral disk not visible in the specimens. Column com-
paratively large and obscurely pentagonal, the nodal joints larger, and with
slightly undulating edges.

Horizon and LocaUty. — Upper part of the Hudson River group, Warren

Co., 0.

The type specimens, which are in our collection, were presented to us by

Dr. S. S. Scoville of Lebanon.

I - -r

4 I

■■■"."I '-5!^"

THYSANOCRINID^ W. and Sp.

(GLYPTASTERIDJi: W. and Sp. 1885).

DiCYCLic. Lower brachials and interbrachials forming an important part of
THE dorsal cup ; interbrachials well defined. Radials in contact except

AT the posterior SIDE, WHERE THEY ARE SEPARATED BY AN ANAL PLATE.

Anuli/sis of the Genera.
Infrabasals 5..

A. Anal side slioiitly elevated. Asvs without a tube.

1. First anal plute followed hij three plates.

a. Dorsal cup deep.

Arms uniseiial, 10 Pttchocrinus.

Arms biserial, erect, ten to twenty Thysanocrinus.

b. Dorsal cup short, almost flat.

Arms pendent, posterior oral and radial dome plates

spiniferous Hyptiocrinus.

2. All interbrachiul spaces liavlng a single large plate .... Idiocbinus.
■"B. Anal side BULfii.vo. Axus at the end of a tube,

1. First anal plate followed by three small plates.

Rays prodnced into tubular extensions.

Infrabasals large Lampteeocrinus.

2. First anal plate followed by three large pilates.

Rays branching in the regular way.

Infrabasals small Siphonocrinus,

Geological and Geographical Distribution.
Number of known species,

(Open figures indicate American, those marlved ( ), European.)

Formation.

TlITSANOCRIXin.t.

General.

American.

Approximate

Kuropean
Equivalents.

P.4

2
s

/ Upper
( Lower

Niagara.

Dudley
Gotland.

5(7)

Huds. River,

2 i

Total species ... 23

5(7)

Itil

THYSANOCRIXIDiE.

18D

Remarks. — "We have clianged the name Glyptasteiidfe, whieli we pro-
posed in 1885,* into Thysiuiocrinidre, because we found it necessary to give
up Hall's genus Gli/pUtdcr. We also discard Dwicmcnnus Phillips, and Fn-
crinus Angelin, and arrange the species of both luider T/i'/miiominis-.i That
Phillips' figures oi Dinwoenims were insufficient for generic identification, is
shown by the fact that the genus has been referred by Koeiner and Dujardin

Fir. 8. T/iymnocriiiiis.

Q-

^ "S^ f^

Fifi. 9. LiiinplfrorriDiix.

and Hupe to the Cyathocrinido9, while Zittel 'made it the type of a mono-
cyclic family. Glypiaster and Eiwrimis were placed by Zittel along with
Lamptcrocrinm, Archwocrmm, and Gli/piocrinns under the Glyptocrinidaj ; in
which he was followed by S. A. Miller, who added Rctcocrimis and Xaiocrimis,
but withdrew them again in 1889. Tlii/smwcrhms was placed at first by both
authors under the Ilhodocrinidaj, from which afterwards Miller removed it to
the Glyptasteridte.

The Thysanocrinidie have their closest affinities with the Ehodocrinidaj.
Both are dicyclic, but in the RhodocrinidiB the interradials at all five sides
are in contact with the basals, thus, as a general rule, completely isolating
the radials laterally ; while in the Thysanocrinidre the radials are in contact
all around except at the posterior side, where the anal plate overlies the
basals. This bilateral symmetry in the arrangement of the plates of the
dorsal cup is accompanied by a marked asymmetry in the general form of
the calyx, and especially of the ventral disk, which is more or less enlarged

111

* Revision, Part III., p. 89.

t See Hiulcr Tlii/saiwi-riinis.

190

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

posteriorly in most of the species of tlie Thysanocrinidoe. In the new genus
Idioci'imts, in which there is but one interbrachial plate to each of the five
sides, there is no special anal plate, and the posterior interradial, which is
larger and rests upon the basals, serves as the anal.

The family is confined to the Silurian, and is composed of six genera,
with twenty-three species, of which sixteen are from America, and seven
from the upper Silurian of England and Sweden.

1830.
1S41.
1850.
1852.
1852.
185-2.
1855.
1857.

185.9.

1802.

1S63.
1873.
1878.
1S7S.

1879.

18S1.

1889.

THTSANOCRINUS Hall.

Dimerocrinm — Phillips; Murcliisoii's Silur. Syst., p. 074, Plate 17, Figs. 4 and 5.

IHmerocrinus — .MCi.lkr; Monatshcr. Berlin. Akad. d. Wisseiiscli., p. 208.

Uimerocrhius — d'Ouhigny ; Prodrome I., p. 40.

Glt/ptaster — Wxhi,; Paliroiit. N. York, Vol. XL, p. 187.

Thymmcrinus — Hall; Ibid. p. 190.

Dimerocrinus — u'OnniGNY ; Cours I'lenicnt., Part 11., p. 142.

Dimerocrimis — Hokmeb; Lelluca Geognost. (Ausg. 3), p. 237.

( Thysa„oerii,H.'< \ _ ^^^^^^ . ^^^^^^ j^ Paleont., Vol. IV., pp. 317 wid 318, Plate C, Tig. 13.

( DiiiierorriiiHS )
JJimerorriiius — lklvncimoii ; Siliirla (3d cd.), p. 535, Plate 13, Figs. 4 and 5.

( Thymnacnnm ) _Di,j4iin,N and IIupk; Hist. Natnr. des Zoophytes, pp. 128 and 131.

I himerocniiHs )

Qlyptanter — WKU.; Trans. Albany Inst., Vol. IV., p. 202.
D'merocnuus — 'SsK\.xw.\ Catnl. Oeol. Mnscnm, Cambridge, p. 120.
Glyptaster — WkiA.; 28tli Hep. N. Y. Stale Mus. Nat. Hist. (ed. 2), pp. 131 and 133.
Eiicriiiiis — Angklin; Iconogr. Criii Sueciie, p. 24.

/ Thymnocrinm \

\ — Zitiel ; Handb. d. Palxont., Vol. I., pp. 368 and 375.

-W. and Sp.; Revision Palieocr., Part H., pp. 193 to 199. Also ibid., Part
III., p. 101.

Glyiiliister

Dimerocrinus
. Eiicriiiiia
' Glyf taster

Dimerocriniin
I E/ii-riiiiis
•■ Thymnocrmus (syii. of Dimerocrinus).

(. Glyptaster
< Eiicriims
' Tliysanocr

[■ — S. A.
fill us )

MiLLEK ; N. Am. Geol. and Palffiontology.

Syn. Dimerocrinus Phillips.
Syn. Glyptaster Hall.
Syn. Eucrinus Angelin.

Calyx subglobose, urn or bell-shaped ; the rays marked by a more or less
conspicuous ridge; the general surface of the plates smooth or variously
ornamented. Tnfrabasals five, small, barely protruding beyond the column,
or entirely hidden by it. Basals five, four of them equal, angular alcove ; the
fifth truncated, and supporting a large anal plate. Eadials considerably
larger than the costals, their lower sides distinctly angular, the lateral faces
comparatively short. Costals two. Arms ten or twenty, rather strong and

■!:iv i

THYSANOCRINID.E.

191

biserial ; pinnules long. The first interbracliial large, resting upon the
sloping upper corners of two radials and against the costals. There are two
plates in the second range, and often smaller ones above, which connect with
the plates of the disk. The anal side considerably wider; the first plate
large, hexagonal, resting upon the posterior basal ; the s-econd range contain-
ing three plates. Some species have an uninterrupted row of anal plates all
the way to the anal opening. Interdistichals generally represented and rather
large. Structure of the ventral disk and position of the anus only known
in one species. (See Thysanocrimis inornaUts) column round or obtusely
pentangular.

Distribution. — Restricted to the Niagara group of America, the Wenlock
group of England, and its equivalent in Sweden.

Type of the genus. — Thysumcrimis liliiformis Hall.

Remarks. — We have reduced Dimcrocrinus, Ghjptaster, TInjsanocrimis
and Eucriims to one genus, finding it utterly impossible to distingui.sh them
generically. There is some doubt, however, by what name the genus should
be known. The name Diwerocrinus was applied by Phillips to two species
from Dudley, D. decadcwtylns and D. icosidactylus. Both wore figured but
not described, and the figures were poor and did not reveal the character-
istics of the geinis. A meagre description was given by Miiller, who men-
tioned " a pelvis," succeeded by 3 X 5 radials, and two series of arm plates.
D'Orbigny described it with three basals, succeeded by three rings of plates.
From such vague and incorrect descriptions, Hall could not suspect that
a species with five ba.sals and infrabasals would be generically identical with
species described as possessing three basals and no infraba.«als, and we believe
he was justified in proposing for his species a new genus. Pictet and
Dujardin and Hup^, who accepted both genera, placed them near together.
Zittel, however, even refers them to distinct families. We were the first to
point out the generic identity of Thysanocrimis with the forms which are
held to represent Dimcrocrinus dccadactylus and D. icosidactylus, but di.s-
criminatcd in favor of the older name Dimcrocrinvs, which we now think
was scarcely fair to Hall. Besides, we accepted Glyptastcr and Encrimts,
though with some hesitation, making the latter a subgenus of the former.
The name Glyptastcr was proposed for a solitary specimen, described ns
6. hrachiatus, in which all the plates of the calyx were obscured by matrix,
but showing ten spreading biserial arms without visible pinnules, and it
was principally upon the absence of pinnules, it seems, that the genus was

-- 1

102

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

founded. Through the kindness of Prof. Whitfield we were permitted to
examine this specimen, and to free it from the surrounding matrix, when we
found tiie pinnulco well developed, and the plates of the calyx arranged as
in the typical form of Thijsanocrimis (Plate XVIII. Fig. 4).

Eucrinus was separated from Tlnjmnocrinus on account of having twenty
arms, as against ten in the latter. A bifurcation or two, more or less, cannot
be regarded as a good generic distinction, and we therefore place Angolin's
species : Eucrinus iHfemHllulls, E. Imvls, E. ormifus, E. qmnqitamjularis and
E. sjjeciosns, under Thysanocrinus ; but not his E. minor or E. venustus, which
are types of a different genus. Rhodocrimis quinquehhus Schultze, which we
formerly placed under Eucrinus, is a Rliodocrinoid. Thysanociinm {lihodo-
crinus) viicrvhasilis, and 7'h. (R/iodocrinus) pyriformis Billings, have been re-
ferred by us to Archavcrinus ; Th. immaturus to Idiocrinus. TTiysanocrimis
wnhatus and Th. cunalictdutus are named from arm fragments. Dimerocrinus
oliijoptilis, and its synonym D. cqMis from Russia, belong to Taxocrinus.
Gli/ptaster penUoHjuluris Hall is described from internal casts, and is, to say
the least, a doubtful species. Cijathocrinus ivcddroncnsis S. A. Miller {Dimcro-
rrlnns icaldroncusis W. and Sp.) cannot be identified from the description and
liguie, but may be a young Tlajsaiwcrinus inoniatus. Neither can Ghjptaskr
E(jani S. A. Miller, which is described from a fragmentary specimen.

Thysanocrinus liliiformiB Hall.
Plate XVIII. Fig. 4-

1S52. nymnorriiius li/ii/oniiis — ll\LL; Pnhtoiit. N. York, Vol. II., p. 1S8, Figs. Iff-/.

1S81. Dimcroniiiiis li/iijbmis—W. mid Sp. ; Revision I'uliuocr., Pint II., p. 199, and Proceed. Acad. Nat.

Sci. Phila., p. 373.
18S9. ni/sciiioeriiiHs lilii/oruiis — S. A. Miller; N. Amcr. Geol. and Palrcout., p. 2S6.

Form of calyx apparently globose (the exact shape cannot be ascertained
owing to the somewhat crushed condition of the type specimen) ; the plates
ornamented by elongate nodes or interrupted stritc, which give to the surface
a corrugated appearance.

Infrabasals small, scarcely visible in a side view. Basals nearly as large
as the radials; that of the anal side oven larger and broadly truncate, the
others angular above. All plates in a radial direction provided with a low.
almost flat, obscure ridge, following the median line of the plates, and
covered by longitudinal strife which are continued into the arms. Radials
wider than long, but slightly angular below; their lateral faces short, leaving

v..

TIIYSAX0CR1N1D7E.

103

a deep notch for the reception of the first interbrachials. Costnls about of
equal size, considerably snuiller than the radials. Arms ten, rather stout, the
two lower plates, which are included in the calyx, longer than the free plates;
the latter short, arranged in two series, with a few cuneate interlocking joints
at the proximal end. Pinnules long, closely packed ; composed of aliout six
remarkably long joints, which are thickest at the ends. First interbrachials
as large as the radials ; succeeded by two much smaller plates, and a few
still smaller ones above. Anal plate large, resting upon the truncated basal ;
succeeded by three plates in the second row. Siructure of di.«k and posif-on
of aral opening unknown. Column round, strong, the nodal joints wider and
longer, rounded at their edges.

Iloruon and Locali/ij. — Niagara group ; Lockjjort, N. Y.

Type in the Museum of Cornell University at Ithaca.

Thysanocrinus inornatus (Ham.).
Plate XVIII. FUjs. 6a, h, c, d, and XIX. Fig. 5.

1863. Olypittster iTOm//«.t — IIai.lj Trniis. Alb. Inst., Vdl. IV., p. 205; nlsn 2Stli Ecp. N, Y. Sintn Mns.

Nat. Hist. (1S79, Ed. 11., p. \\V\\ I'lntc It, Figs. 1-G; ulso lltli Itcj). Gcol. Surv. liuliiinn,

I8S1, p. 203, Plate 13, Figs. 1-6.
1881. Gli/ptaster imrnaliis — W. mid Sr. ; Kcvision ralttocr., Part II., p. 196.

Calyx somewhat urn-shaped, the sides slightly convex ; cross-.section at
the top of the costals pentagonal, the angles corresponding to the rnys ;
across the disticlmls decagonal.

Infrabasals very minute, only the extreme points of the plates visible
beyond the column.* The ornamentation consists of single series of broad,
ill-defined radiating ridges or elevations. Some of the more prominent ones
follow the median line of the rays; while others take a lateral direction,
radiating from the centre of the plates to the margins, where they meet
with similar ridges from the interbrachials and basaks,

Basals large, their lower margins thickened and expanded into nodes —
one to each plate — which stand on a level with the top stem joint, and
form a marked pentalobate rim around it. Eadials larger than the bnsals,
and wider than long. First costals considerably smaller and quadrangular,

• Prof. Hall described tlie " basals " — the infrabasals of modern terminology — as " nmeli developed,
distinetly pcutanguliir, «i(li a donble or triple node on oarh plate, and spreading beyond tlie eolnnin." From
tliis description we s\ispect that the antlior took tbe nodes at tlie lower end of the hasah for plates, and over-
looked the small iiifrnbasals which are rarely observed. AVe draw attention to this, breanse Hall, in compar-
ing this species with bis " Glyptusler" oceidentatis, makes "the greater dcvcloimient of the basal plates"

a specific distinction.

194

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

the second iibout as large ns the firist. DiHticImIs four in the calyx, the rows
wpanited by from one to three intordLstichals. The second distichal bears
a pinnule, wliicii is for the most part incorporated into the calyx. Arms
uidtnown. Interbrachial spaces deeply depressed, so as to give to the calyx
at the arm bases a decidedly lobed appearance ; the first plate nearly as
large as the radials, the two of the second row slightly smaller, followed by
much smaller ones in the third and fourth rows. Anal interradius consider-
ably wider, more depressed, and longitudinally divided by a row of elongate,
hexagonal anal plates, which form a conspicuous, rounded ridge reaching to
the anal opening. The plates at each side of the ridge consist of about the
same number, and are arranged in a similar nuuiner as the interbrachials of
the fovU' other sides. Anal opening subcentral, in the middle of a small pro-
jection. Ventral disk depressed. Orals pushed to the anterior side; four of
them much smaller, and arranged in a !<lightly curving row around the
posterior one, which rests against the anal protuberance. Covering jiicces
of the ambulacra exposed at the surface; they consist of two series of very
short transverse pieces, alternately arranged, forming highly elevated ridges,
Avhich gradually decrease in width as they approach the arms. Interambn-
lacral plates continuous with the interbrtichials ; they are small, irregular, and
form deep depressions upon the surface, which contrast strongly with the
elevations along the ambulacra. Column round ; axial canal above medium
size ; the outer edge of the top joint beautifully erenulated.

Horizon and Localitij. — Niagara group ; Waldron and Hartsville, Ind.,
and Racine, Wise.

Types in the American Museum of Natural History, New York.

Thysanocrinus oocidentalis Hall.
Plate XVIII. Fiqs. 5a, h, c.

; Trniis. Alb. Inst., Vol. IV., p. 204 (Abstr. p. 10); nlso 28th Bcp.
Hist. (cd. 2,), 1S70, p. V.Vi, riiitu 13, Figs. 7-11; also 11th Kcp.

1863. Gli/ptasfer occideiitalis — Hail; Trniis. Alb. Inst

N. York State Mus. Kiit

Gcol. Surv. Indiana, 1S81, p. 262, Plate 12, Fiffs! 7-11.
1881. Olyptasler occideiUatis — W. and Sp. ; Revision Palitocr., Part II., p. 190.

A somewhat larger species than the preceding. Calyx broadly sub-
turbinate, abruptly spreading from the infrabasals ; sides slightly convex ;
plates thin. The brachials of the calyx have on their outer or dorsal surface
a prominent rounded ridge, covered by indistinct longitudinal striae, and
their inner or ventral side has a deep, semi-circular groove. From both

iil

i.H

TIIYSANOCRINID^E.

195

sides of Uic ridge, small radiating lines pass out to the interbracliiuls, form-
ing triangles of wliicli the intervening spaces are granular or covered with
fine striations. Stronger ridgen pass from the radials to adjoining basals,
where two of them meet, and proceed as a single ridge to the infruljasiils.
The latter ridges form around the column a sharply defined pentagon, who.«e
salient angles lie in a radial direction.

Infraba^als of moderate size, forming a narrow belt around the column,
which is visible in a side view. Basals large, without nodes, rapidly spread-
ing. Radials larger than the costals, second costals narrower than the first.
Arms apparently ten, of which in mature specimens the six or seven lower
plates are incorporated ; arm plates comparatively large, elongate, and
slightly wedge-form. Interbrachial plates large; arranged: 1, 2, 3. 3, with
a fifth row at the level of the arm bases. Anal interradius considerably
wider, having three plates in the second row, and four in the third ; — there
being no continuous row of anal plates or any sort of elevation. Intcrdis-
tichals five to seven. Ventral disk unknown. Column round ; axial canal of
moderate size ; pentalobate, the lobes directed radially.

Horizon and Locality, — Niagara group; Waldron and ITartsville, Tnd.

Ti/pes in the American Museum Natural History, New York.

Bemar/i's. — This species differs from T/ii/sanucriiuis inornutiiti in the larger
size of the infrabasals, the arrangement of the plates of the anal side, the
absence of an anal ridge, and in the general ornamentation of the plates.

Ghjptastcr occklentalis (var.) incrchescens is, in our opinion, not sufficiently
distinct to be ranked as a variety.

»l

Thyaanocrinus brachiatus Hall.
Plate XVIII. Fig. 7.

1852. Olj/p/as/t-r iraeHafiis — 'nuu. ; Pnlirniit. N. York, Vol. IT., p. 187, Tlatc 41, T'li;. i.
18S1. G/i/pliis/er briickiiilus — W. and Sr. ; llevisioii Pulujocr., Part II., i). I'JC (Proceed. ."Vcad. Nat. Sci.,
Pliila., p. 370).

Calyx subglobose, having very strong radial ridges which bifurcate at
both ends. The lower branches proceed to the basals, and produce a well
defined pentagon, subdivided into five nearly equal fields by another row of
ridges; the upper branches follow the distichals, and pass into the arms.
The general surface without ornamentation.

Infrabai3als small, but exposed beyond the column, and visible even in
a side view. Basals of moderate size. Radials deeply notched for the

:/l

196

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

reception of the first interbniciiinl, tlieir laterftl faces coininirntively short.
Costiils Hiimller tliiin the radiiils. Anns ten, long, slemler, somewhat Uatttned
on tlie baclt ; the three proximal plates take part in the eal^x, are curved
like the free plates, and are but little larger. The first free brachial is rectan-
gidar, but the succeeding ones gradually turn into cuneato, interlock, and
fnialiy change to biscrial, with the upper and lower faces parallel. Pinnules
long and closely packed. Interbrachials : 1, 2, 2. Anal side wider, the
plates in three ranges, divided by a vertical row of anal plates ; the lower
one of the same size as the radials; the others smaller, decreasing in size
upwards. Structure of the ventral disk, and form of the anus, unknown.
Column pentangular.

Ilorl-ion and LovaJ'ttij. — Niagara group ; Lockport, N. Y.

JiiiKarkn. — Our description and figure are made from Hall's typical
specimen * in the American Museum of Natural History, New York, after
clearing uway the matrix, which brought to light the pinnules and exposed
the calyx plates. That Glijptadcr is generically identical with T/n/saiiocriniis,
nobody will doubt after comparing our figure (Plate XVIII. Fig. 7) with that
of Thi/sanocriims lilUfurmls (Plato XVIll. Fig. 4).

(?) Thyaanoorlnus Halli (Lyon).
Plate XIII. Figs. 9a, h.

ISCl. Modomiiiis Iliilli — Lyon ; I'rocred. Arail. Nat. Sci. Pliilii,, p. 412, Plate 4, Figs. 5a, i.
ISSl. (?) H/io,/arriiiii.i IJnlli—W. and Si'. | Iti'visiou I'ala'ocr., Part II., p. 212.

A large species. Calyx vasiform, a little wider than high, rounded below,
the sides convex; the interradial spaces slightly flattened, and the radial
plates rather sharply elevated, which gives to the cross-.'icction a subpentan-
gular outline. Surface of the plates smooth, the suture lines distinct but not
channeled.

Infrabasals visible beyond the column ; the columnar attachment large,
circular, its outer margin .surrounded by well-defined radiating striae. Basals
large, a little convex ; four of them pentangular or nearly so, the upper
angles almost meeting the interbrachials, sometimes slightly touching them ;
the fifth plate pentangular, broadly truncate above. Eadials and costals
wider than high, gradually decreasing in size upwards. Of distichals only
two are preserved, and only in one division of two of therays. There are only

• Figured by Hall. New York Pateont., Vol. II., Plate 41, Fig. 4.

TIIYSANOCRINin.'E.

197

Mix interbrnchiiilH shown, nrranged : 1, 2, 3 ; but tlicro were probably others
above. Tiie anal inturrailiiis apparently has two plates in the second row,
but the nuJdle one of the next row extends half way down into the second.

Jlwhon and Lucu/ltij. — Ningara group (?) ; near Louisville, Ky.

Jioiiarks. — Tho ti/pi; specimen, which was said to be in the Knapp col-
lection, cannot bo found. Tho two specimens hero figured, from the
Borden Institute of New Providence, Ind., are both somewhat abnormal and
quite fragmentary, ond leave some doubt as to the generic relations of the
species. Not only is tho anal plato followed by only two plates, but the first,
regular interbruchial occasionally touches the basals.

PTYCHOCRINUS W. and Sr. (Emend.).

188S. W. mid Sr. ; Rcvismii riilirocr., Tnrt III., p. 99; nlso rriicocd. Acnd. Nnt. Spl. riiiln., p. 321.

Sjii. <r/y/i/orriiiii.i(m pint) — lUi.i., IS72, iiHli Hep. N. Ycnk Slate fiih. Nut. Hist., p. ;!li7; nlso

.MilkTiind Dvcr, 1878, .louiii. t'incin. Sdc. Nat. Hint., I'late 1, Fit;. 111.
Sjii. (liiiiruiriiiiii (ill purl) — 8. A. .\lll,i.EU ; lSb3, Jourii. Ciiiciii. Soc. Niit. Hist., p. 228 ; mid 1889

N. Ainer. Geol. and l'u!a-<iiit., p. 270.

Specimens small; in form and mode of ornamentation resembling Ghjpto-
crinus. The radial plates marked by a well defined ridge, which passes up
and down tho median line of tho plates, giving to the interradial spaces
a somewhat depressed appearance.

Infrabasals five, small, but generally visible beyond the column. Basals
five, large ; four of them hexagonal, the posterior one heptagonal, truncate
above. Radials and costals of nearly equal size. Costals two. Disticbals
vaiying in number, curved like arm plates. Arms ten to twelve, rather
delicate, and uniserial. Pinnules strong. Interbrachials and interdistichals
not numerous, tho plates definitely arranged. Posterior side with a longi-
tudinal row of anal plates forming a ridge. The first anal plate in a line
with the radials, and always succeeded by a row of three plates, — a second
anal and two interbrachials. Structure of ventral di.sk imperfectly known.
Column cylindrical ; axial canal large, pentalobate, the lobes directed
radially.

Distribution. — Restricted to the Trenton and Hudson River groups of
America.

Type of the genus : Ptijchomnus splendcns (S. A. Miller).

Rcmarls. — Pt)/chocr!inis differs from Tlnjsanocrinus in having delicate
uniserial arms; from Edcocrinus in the definite arrangement of its inter-

198

TlIK C'UIXOIDKA CAMKUATA OK NOHTII AMKHICA.

rndiiil platuH, uiid in linvuig tlu'Mo ruHtiii^ agaiiisl tliu riuliiilN; fiuux f,'li/j)tO'
crinuH in liiiving iniVa basilic, and an anal plate in contact wilii lliu bamds.

S. A. Miller, in IhUll, arranged a number of Hpecies under a propoHed
genuH (IdiiroLrinus, wliicli, liiie Iuh (lljipUnrinna, cnibruceH ii variety of fornix,
containing Hpecies of Ititiovi'nntK, O'lyjitocriiiiin, and a tliird form, for wliich
we i)roposed tho name I'ti/r/iocrlnns, whU MWlvr'n " Cittiirorrliniti" sjjltiKlnis
tts typo. Wo hIiouUI have preferred to accept for tlie latter Miller'« name
Gmrwvinua, if ho liad not expressly selected as the type of his genus Hall's
" Gbjiitovriiiua" Oimdli, which is a typical Jiiiiocrtnua.

*' GJijIilovrlnus" prlnruH E. IJillings, which Walter R. Billing^ supposed to
have infrabasals, ond which wo placed provinionally under rtydiomnua, hua
sinco been referred by us to rd'iyli/jjtocrinun,

Ftyohoorinua splendens (S. A. Millkk).
PMe XVIII, Fi</s.3n,b.

18S3. Gaurocrinut tplendem — S. \. Miller; Jourii, Ciiiciii. Soc. Nnt. Hist., Vol. VI., p. 230, Plate 11,

FiR. 3.
1SS3. Pti/cliocrinHi tptemhna — W. niid Si'.; Kovisioii I'lilitocr. I'lirt III., p. 101.
1880. (liiunii'riiiui ipleiident — 8. A. Miller; N. Amer. Gcul. mid Piiliroiit., \i. 247.

Calyx elongate, obconical ; cress-section pentangular with concave sldc^.
Tho plates of the rays folded along tho median lino, so as to form broad,
rounded ridgo.s, from which branches proceed to the basals, meeting there
smaller ridges from the infrabasals. Surface of plates studded with rather
conspicuous, elongate tubercles, of which a transverse one passes over the
suture of two adjoining radials without touching the radial ridges. The first
interbrachials have seven tubercles, a central one surrounded by six others ;
the latter occupying the outer margins, resting in part upon adjoining plates.
The higher interbrachials have only a central tubercle.

Infrabasals small, only their extreme upper points visible in a side view.
Basals large, higher than wide ; the posterior one broadly truncated. Radials
a little larger than the basals, about as long as wide. First costals some-
wliat longer than wide, and hexagonal ; the upper angles of the axillarics not
truncated, tho interdistichals not touching them. Distichals twelve to four-
teen, of which the three to four lower ones take part in the calyx, the
succeeding ones being free arm plates ; the upper one gives ofT two arms,
which remain simple. Arms delicate, gradually tapering to a slender point ;
composed of a single series of rather long, wedgeform joints. Pinnules

TUVSANOCRINin.E.

190

stout, wlflely no|mratcil. Tho firnt pitimilc, wliicli in fixo<l, more erect, ami
Htroiij^or tliiin tho othcru, in given olT tVom tho outer wide of tho Mecontl din-
tichiil, tli( M'conil from tho inner Hide of the fourtii phito; nil nncccudin^^
pliitoH except the axillnricH beinj( pinnuIe-lK'uriiij^. Interliracliiiil npiiceH
deeply depressed; llit' li •<t pliito liirge, followed l)y two Hiiudler ones, mid
tlie,«e by three in the third row, iind others iihove. Anal widi' wider, ><)nie-
whnt nti/nlar aloii}^ tl/# median line; tho Cunt nnal plate rcNtin;r iijjon the
truncate bnwil. Internxiilarn<t three, in two rnnj^cH ; each ono nuirked hy
a Hniall, central tuhercle. Construction nf disk and form of anus unknown.
C.duinn round, slicrlitly taperinj^ ; tho nodal joints at their outer ovlges
faintly crenulated ; axial canal huyo. pentalolmte.

Ilorhon and LmiUty. — Trenton group ; Cape Girardeau, Mo., and
Alexander Co., 111.

Ti/pvH in tho collection of S. A. Miller, Cincinnati.

187a.

1873.
1879.

1881,

1881.
1883.

1885.

Ftyohoorinus parvus (ii ai.i.).
Plate XVIII, Fi(js. la, h and 2.

nli/iiliirrhmn pnrriii — Ham.; T)c'»pr. New. Criii., (■/(•., Plalr 1, l''i|f. 17 (Hitlunil UiMriiiliiiii) ; also

mh Hep. N. V, State C'ul). Nut. lli»t., p. 2i)7, I'liil.' V., I'if,'. 17.
Oli/plijci-iiiHf luirnii — MtKK; I'lilu'oiit., Ohio, Vol. 1., p. 3(1, I'lali' i. Figs. \a, h.
Gli/iiliii-riiiiif iiiii/iiliiriii — Mii.i.Kii mill Dveh; Jouni. Ciiieiii. Soc. Niil. Hist., I'lalo 1, Fi(f. 10.
I lll,/i,l,.-rim„ luinn, \ _y; „,„i gp . Revisinn I'uliiM.or., pMrt IF, pp, 1S8, 189; mill Amor.
i ah„,h;crum, „mjHUm> ■ j,,,,„, y^j^ j>,>,.,_ y^, y^y^^^ j.^, i!,-,5-2flS.
\ Ki-li'ui-riiim yi-urilis J
Rf/ivrriiiH-i i/niriliii — Wetiik.rdy; Ciiicin. Jinirii. Nut. Sci., Vol. IV., Plnlp 2, Fig. 3.

titorriiius piirriD ) — 8. A. Mll.i.Kli, Juuni. Ciiieiu. Sue. Nat, Iii>t., Vol. VI,, pp. 22t niiil
(Hrocriinii aiiffii/iiria ) 2iOj ami 1SS9, North AiniT. Oeol. and I'ala'ont., pp. 217 miil 21H.

( (!/i//i/orriiiH.i juirnin \ •
( (liinroiriniia aiiguliirit )

fPti/chorrinuH /lurrnn )
I't^i'hocriniit uiujuUifis )

PlUrhocnnm parm, \ _ y^ ^,„, g,. . m,vi,ion p„l„ocr , Part III., p. 100.

Of small size. Calyx obconical, with slightly convex sides ; the radial
plates marked with prominent rounded ridges, which extend to nearly the
fidl width of the plates ; interbrachial spaces flat, plates very slightly con-
vex and without ornamentation.

Infrabasals miinite, only the outer angles of the plates visible beyond
the column. Bnsals large, higher than wide ; their surfaces strongly convex.
Interbasal sutures deeply depre.ssod, and the depression continued to the
radials, of which the lower ends bend inward. Radials somewhat larger than
the first costals. The second costals of similar form to tho radials, only
reversed, being angular above instead of below. Distichals 2 X 10, about as
wide as long, the upper one axillary. Arms four to the ray, free from

> I

200

THE CRINOIDEA CAIIERATA OF NORTH AMERICA.

the first or second palmar; composed of wedgoshaped joints, wliicli arc as
long as wide, and rounded on the back. Pinnules stout, well separated.
Interbrachial spaces depressed, flat ; the first plate of the regular sides as
large as the costals ; followed by two plates in tho second row, and a number
of others, which, though well defined, are more or less irregular in their
arrangement. Anal side wider, divided by a longitudinal row of hexagonal
plates ; the plates at each side of this row about as numerous as the whole
series of plates of the four regular sides. Interaxillaries five or more. Con-
struction of the ventral disk unknown. Column round ; axial canal of
medium size.

IIoiizoH and Locality. — Hudson River group ; Cincinnati, 0.

Remarks. — Ghjptocrinus ( Gaurocrinus) aiujiilaris Miller, and lietcocrimts
gracilis Wethcrby, are undoubtedly synonyms of Hall's "Glijptocrinns" 2)ar-
viis. Mr. Miller was good enough to send us two specimens, which he had
himself identified .as " Gaurocrinus " aurjularis, and Mr. Vaupel kindly loaned
us the type of Ecteocrinm gracilis. Both specimens are figured on Plate
XVHL, and a comparison of them with Hall's type of" Glijpfocrimis'^ i^arvus
will prove that they all represent one species.

HYPTIOCRINUS W. and Sp.

(uTTTios, bending back ; Kpivov, a lily).

1892, W. and Sr.; Am. Geologist, Vol. X. (September), p. 138.

Syu. Ci//i/iocriiiiis S. A. Milleu (October 20, 1892) ; Adv. Sheets, 18th Rep. Geol. Surv. Indiana,
p. 50.

Name referring to the character of the arms, which hang downward.
Calyx depressed, wheel-shaped. Infrabasals five, small. Basals five, four of
them equal, angular at the upper end ; the posterior one truncated by
the anal plate. Radials comparatively small, all heptngonal. Costals two.
Fixed brachials rather large, except the first costals, which are quite short,
and quadrangular. Distlchals one, the distal face broadly truncated; fol-
lowed by several sharply cuneate pieces, which interlock, and of which the
two or three proximal ones (in the type) lake part in the calyx. Arms
stout, probably biserial, and pendent, to judge from the arm openings, which
are directed obliquely downward. First interbrachials of the regular sides
very large, succeeded by several rows of sriialler pieces. Anal plate touching
the biTsak and rising above the radials; supporting three much smaller
plates and others above. Ventral disk depressed ; the posterior oral and the

TIIYSANOCRINIDiE.

201

radial dome plates spinous; the anus excentric and at the top of a large
protuberance.

Distribution. — So far as known, restricted to the Niagara group of
Indiana.

liemarks. — The genus has its closest relations with Tliysanocrinus, from
which it differs in the depressed form of the calyx, the pendent arms, and
in the spine-bearing disk.

Hyptiocrinus typus W. and Sp. (nov. spec).
Plate XIX, Figs. 6a to c.

1892. W. and Sp. ; Am. Geologist, Vol. X. (Scptniibd), p. 13S.

Syn. C^phocrium Goi-byi S. A. Milleu (October 20, 1S92). Adv. Sheets 18th Rep. Geol. Siirv.
Indiana, p. 51, Plate 7, Figs. 14, 15, 16.

Specimens of medium size. Calyx wheel-shaped, nearly once and a half
as wide as high. Dorsal cup broadly obconical to the top of the costals, then
flanging outward and somewhat downward. Arm regions not lobed, but the
upper margins of the interbrachial and interdistichal spaces formed into
sharp edges by means of corresponding depressions in the dorsal cup and
tegmen. Costals and distichals marked by rounded, longitudinal ridges,
following the median line of the plates. Veutral disk a little higher than
the dorsal cup, its lateral margins slightly bulging, the lower edge some-
what projecting over the upper margin of the dorsal cup. Plates flat, their
surface in well preserved specimens densely covered by fine granules.

Infrabasals small, hidden by the column ; forming a flat pentngonal disk.
Basals rather large, about as wide as hmg ; curving abruptly upwards ; the
posterior one slightly truncated at the upper end ; the interbasal suture lines
distinctly grooved. Radials twice as wide as long, their proximal ends dis-
tinctly angular. First costals much shorter and narrower than the radials ;
quadrangular. Second costals longer and a little wider than the first ; their
lateral faces short; the sloping upper faces making a right angle. First
distichals as large as the axillary costals, followed by two or three cuneate
plates in the calyx, which slightly interlock. Structure of the free arms not
observed, but they were apparently biserial and quite heavy and pendent.
First interbrachials of the regular sides the largest plates of the calyx, rising
to the height of the first distichals, and being succeeded by two rows of two
plates each. The anal plate a little higher than the radials, supporting three,
two, and two, smivUer plates. Interdistich.als one, small. Posterior oral nearly

'It

H
'11

■1

202

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

central, large, and extended into a heavy, short spuie ; the other four orals
proportionally small and almost flat. Radial dome plates represented by
plates of a first and second order, those of the latter by two or throe plates
to each division, alternately arranged ; all large and spine-bearing. The
spines near the outer margins of the disk project obliquely outward, and are
visible from a dorsal view of the calyx. Interambulacral plates numerous, of
the size of the smaller orals, and irregularly arranged. Anus excentric, at
the top of a large ovoid protuberance, rising conspicuously above the general
plane of the disk.

Horizon and Loealitij. — Niagara group ; St. Paul, Shelby Co., Ind.

Ti/pe in the collection of Wachsmuth and Springer.

IDIOCRINUS W. and Sp. (nov. gen.").

(iSios, peculiar; Kplvov, a lily).

1S92. W. and Sp. ; Am. Geologist, Vol. X. (Scptcmbci), p. 135.

Syu. Gii:iicri/ius S. A. Miller (October 20, 1392) ; Adv. Sheets, 18th Rep. Geo!. Surv. Indiana,
p. 49.

Infrabasals apparently five, extremely small, placed at the bottom of
a more or less deep concavity, and completely hidden by the column. Basals
five, very large ; the posterior one truncated by the anal plate. Radials quite
large ; three of them heptagonal, the two adjoining the anal side hexagonal.
Costals two, very short; the lirst quadrangular; the second pentangular,
the upper angle rather obtuse. Distichals two in the calyx ; short. Inter-
radial areas at all sides composed of a single large plate, which rises to the
top of the dorsal cup ; that of the anal side resting upon the basals, the four
others upon the sloping upper faces of the radials. Ventral disk quite vari-
able in form ; covered by a large, probably anchylosed oral pyramid. The
ambulacra tegminal ; the interambulacral spaces formed of single plates,
of which the posterior one is perforated by the anus, which is excentric.
Arms and column unknown.

T^pe. — Idiocrimts elongatus.

Distribution. — So far as known, restricted to the Niagara group of
America.

licmarls. — This genus differs from all other dicyclic Camerata in having
a single plate in the anal area, in its central, undivided oral pyramid, and in
having but one interambulacral plate to each side of the disk.

ft'

TIIYSANOCRINIDiE.

203

Idioorinus elongatus W. mid Sp.
Plate XVIII. Fi(js. Sa to c.

1892. W. and Sr., Am. Geologist, Vol. X. (Sei)teiiibei), p. 13G.

Syii. Guzucrimis iiiornalus S. A. Milieu; Adv. Sheets IStli Rep. Geol. Surv. ludiaiin, p. 49, Pln(o
5, Figs. 9, ]0, 15, 16, 17 (published October 20), 1S92.

A small species. Calyx obconical ; the ventral clii<k almost on a level
with the upper margins of the dorsal cup; the cup deeply excavated at the
bottom, the basals forming a large funnel-shaped pit. Plates without orna-
mentation and flat, except the radials, which are a little convex, and rise
slightly above the plane of the cup. Suture lines not grooved.

Infrabasals minute, constituting the bottom of the basal concavity. Basals
extremely large and elongate, the lower end curving abruptly inward, and
forming a sharp edge around the bottom of the calyx ; the exposed part of
the plates rising to more than one third the length of the dorsal cup. Ivadi-
als once and a half as wide as long, distinctly angular at their lower faces ;
the two posterior plates hexagonal, being distinctly truncated by the anal
plate. Costtals together less than half the size of tiie radials; the first linear;
the second a very little longer, and its upper angles quite obtuse. Dis-
tichals two, somewhat higher and wider than the costal.s ; the upper semi-
free. Interbraehials one, those of the four regular sides resting upon the
deeply sloping sides of the radials, the anal one upon the narrowly truncated
basal ; all extending to the upper end of the calyx, and all longer than wide.
Arms apparently ten, their dorsal faces flat.

Ventral disk but slightly elevated, consisting of five large, oblong, trian-
gular plates, one to each area, which do not meet in the centre, but leave
a moderately large, pentalobate open space at the summit. Tlic sides at the
lower ends of the plates to two thirds their length are not in contact, but
leave elongate spaces, which were apparently occupied by the ambulacra ;
the lateral edges are tdightly serrated, and bend outward for the reception of
the covering pieces. Near the summit, the plates meet in a similar manner
as the deltoids of the Blastoid genus Pcntrcmites, by means of lateral pro-
cesses, and these are converted into grooves which comnuinioate with the
vacant .space in the centre. The structure is such as to indicate that the
ambulacra followed these grooves before entering the peristojiie, and that
the centre was covered by an oral pj'ramid, as in the allied Idiocrinm vcntrU
casus, in Avhich the pyramid was found in position. The posterior inter-

( : i

I t" I

i1 '

i^i

204

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

ambulacral plate is somewhat wider, and perforated by the anus to such an
extent as to leave only a narrow skeleton at the lateral margins.

Gazacrinm Miller is identical with Idiovvimis, the latter name having
priority. Miller described the genus as monocyclic instead of dicyclic, and
he speaks of a " vault sustained by a specialized frame work with ambulacral
canals connecting tlie arms with the central orifice." This is misleading, for
the plates exposed at the oral surface are true plates of the disk, and the
open spaces which apjjcar in the specimens were closed by orals and ambu-
lacral plates. There was no central orifice, the peristome being covered us
in all other Camerata.

Horizon and Locality. — Upper part of Niagara group ; St. Paul, Shelby
Co., Ind.

Ty2)e in the collection of Wachsmuth and Springer.

Remarks. — Mr. Miller, in describing the arm plates of this species,
states they are long, and their edges " are transversely serrated on the
inside, half the depth of the plates." We observed this structure in our
specimen, and were at first inclined to regard the edges as formed of small
side pieces, and so described them in the " American Geologist." Since then
on further cleaning the specimen, we have become convinced that the parts
in question are mere extensions of the arm plates, which are short, and that
the line of union is slightly gaping to facilitate motion.

Another point in Miller's description should be noticed. He says: "There
are three longitudinal furrows on the inside of each radial series, shown at
the top of the secondary radials; this gives fifteen furrows at the top of the
secondary radials, one in the middle of each plate, and the other at the
suture ; " and he alludes to this as a peculiarity entirely new to him. He
evidently misunderstood the structure, for our specimen clearly shows but
one furrow to each brachial, of which those from the distichals unite upon
the axillary costals at the extreme edge of the disk. The supposed marginal
furrows do not enter the disk, and are mere depressions at the lateral margins
of the distichals, formed by the highly projecting serrated edges of the
ambulacral furrows at each side.

TIIYSANOCKINID^E.

205

IdiOCrinUS ventriOOSUS W. ami Sr. (nov. spec).

Plate XVIII. Fi(js. 9a, b.

A very small species. Calyx as wide as high ; height of dorsal cup about
equal to that of the tegmen ; the former bowl-shaped, the cup obtusely
pyramidal. Plates smooth ; the radials and costals somewhat longitudinally
convex, causing a small depression of the interbrachial spaces. Suture lines
slightly grooved.

Infrabasals extremely small, and completely covered by the column ;
placed at the bottom of a small circular cavity, formed by the lower ends of
the basals. Basals of moderate size, their lower ends incurving and forming
the sides of the concavity, their upper angles slightly bending upwards.
Radials once and a half as large as the two costals together, and twice as
wide as long ; three of them hcptagonal, the two posterior ones hexagonal.
First costals quadrangular, much narrower than the radials, and three times
as wide as long; the second of nearly the same width as the first, but longer.
Distichals narrower and shorter than the second costals. Interbrachials large,
subelliptical ; that of the anal side a little wider, and slightly truncating the
posterior basal. Oral pyramid convex, a very little tumid, extremely large
for the size of the species, perfectly closed at the summit, and the inter-oral
sutures obsolete. The outer surface of the pyramid is covered with well
defined radiating ridges, which proceed from the middle of the plate to the
outer margins, increasing in height and width as they pass outward. Ten of
these ridges are prominent, and project outward around the circumference,
thus giving to the plate the aspect of a ten-rayed star. The inner floor is
excavated centrally, and there are five deep grooves passing out in a radial
direction. The interambulacral plates long, slender and cuneate, attached
with their sharp upper ends to the inner margins of the orals. They project
outward so as to form at their sides open spaces for the reception of the
ambulacra. Other parts unknown.

Horizon and Locality. — Upper part of Niagara group ; near St. Paul, Ind.

Type in the collection of Wachsmuth and Springer.

Remarks. — The oral pyramid of this species, which is found occasionally
detached from the body, was regarded by Miller, Benedict, and ourselves, as
probably representing the ventral structure of a Pisocrinus. This appeared
quite plausible, as it was expected from analogy that in Pisocrimis, as in the

206

TIIK CRIXOIDKA CAJIKRATA OF NORTH AMERICA.

allied Si/mhathocrinm, Allmjccrinus and ILiplocrinus, the ventral disk consisted
of onils only, and the plate fitted approximately upon the cup of one of the
species, which occurs in the same bed. A well preserved oral pyramid of this
genus is figured on Plato III. P'ig. 15, which may belong to this species.

(-0 Idioorinus immaturus (Hall).
Plate XVIII, Figs. 10a, h, c.

1S51. Thtjmmrrinm immalunix — IIai.l; Pnltcont. N. York, Vol. 11., p. 191, Plntc 42, Figs, lu-/

This small species, so far as known, in its general habitus so closely
resembles Idiocrimts that we are inclined to regard it as belonging to this
genus. It is more depressed than / clonrjutus, the sides of the cup are more
convex, the base more concave, and the costals proportionally higher.
Neither arms nor ventral disk are known.

Horizon and Lomllty. — Niagara group ; Lockport, N. Y.

(?) Idiocrinus tennesseensis (Wouthe.n).
Plate XVIII, Fifj. 11.

1890. C'li/roeriniis feiiiies.ieeii.ih — WoRTiiENj Gcol. Rep. Illinois, Vol. VITT., p. 0.">, Plate 14, Fig. 1.

Dorsal cup apparently obconical. Plates almost flat, and without orna-
mentation ; suture lines indistinctly grooved,

Infrabasals three, forming a slightly projecting rim around the bottom of
the calyx. Basals rather large, fully as high as wide, three of them pentan-
gular, the others being covered by matrix. Eadials one fourth wider than
long, the lower faces distinctly angular. Costals two, narrower than the
radials ; the first quadrangular and extremely short, more than three times
as wide as long ; the second a little longer than the first, and obtusely an-
gular above. Distichals two in the calyx ; the proximal one as long as, or
longer than, the axillary costal ; the second a little wider than the free arm
lilatc's, but not higher. Arms two from the calyx, moderately stout ; com-
posed of rather long, quadrangular joints, branching (at least in one of the
arms) from the fourth free plate. Interbrachials, as seen at two sides, subel-
liptical, extending to the full height of the first distichals, slightly grooved
longitudinally at the median line. Stem round, the nodal joints high, the
outer faces convex and somewhat projecting. All other parts of the species
unknown.

TIIYSANOCRINlDiE.

207

Horizon and Locality. — Niiigara group; near Clifton, Wayne Co., Tenn.

Tt/2)e in the Illinois State collection, Springfield.

Eeimn-h. — We refer the above species to this genus with considerable
doubt, although it has close affinities with it in the structure of the dorsal
cup; but it differs from the typical form in having three rather large,
projecting infrabasnls — that having apparently five — and the plates are
completely covered by the stem. Whether it has the same sort of ventral
disk cannot be ascertained from the specimen, nor do we know anything
about the structure of the anal side. Worthen referred the species to the
monocyclic genus Ccntroctinus, and apparently took the infrabasnls for a
projecting rim of the basals.

LAMPTEROCRINUS Roemeb.

I860. F. Roemeb; Silur. Fauna. Wni. Toiin., p. 37.

1803. Hall; Trans. Albany Institute, Vol. IV., p. 202.

1366. S11U.M. ; Trans. Aciiil. Sci. Si. Lcmis (Cut. Tnlitoz. Foss., p. 378).

18G8. Hall; 2OII1 Ucp. N. York States Cab. Nat. Hist., p. 328.

1S70. Zittel; Handb. iler Pabrontologie, Vol. I., p. 375.

1881. W. and Sp. ; Revision Pataocr,, I'nrt II., p. 199 (Proceed. Acad. Nat. Sci., Philn. 1S81, p. 373).

1882. De Loriol; Paleont. Franfaiso, Tome XI. (Crinoides), p. 59.

1885. W. and Sp. ; Revision I'alieocr., Part III., p. 101 (Proceed. Acad. Nat. Sci. Pliila,, p. 323).
1889. S. A. Miller ; N. Anier. Gcol. and Paliuont., p. 257.

Syn. A//tf«oc/-i««.< — Troost, 1850 (not Agassiz, ISIO), Cat. Foss. Tcun., p. 00.

Calyx unaymmetrical, elongate-obpyramidal, the rays formed into tubular
appendages bearing the arms. Ventral disk greatly inflated posteriorly, and
extended into a large tube, pushing the centre of radiation to the anterior
side of the calyx.

Infrabasals anchylosed, fonning a large spreading cup. Basals five, very
large, four of them equal, angular above; the posterior one considerably
higher, and truncated at the upper face. Radials very large. Costals two,
the first hexagonal, the second supporting at one side a lateral arm, at the
other the distichals. The higher orders of radials, from the distichals up,
are curved like arm plates, and with the covering pieces form a rigid tube,
from which small arms are given o(T alternately at intervals. In the typical
species the distichals consist of three short pieces, the upper one axillary,
supporting at one side the second arm, at the other the palmars, of which
only the first plate has been observed.

Interbrachials large, passing uninterruptedly from the dorsal cup into
the tegmen; there is one plate in the first row, followed by two in the

I t

208

THE CIUXOIUKA CAMKRATA OF NORl'II A5IKIUCA.

Hcconil. At the anal side, which is somewhat wider, the first oiial plate
rests upon tlip basals, and supports three small plates in the next range,
which are succeeded by three plates, and others above. Ventral disk asym-
metrical, strongly bulging at the posterior side, and supporting a large
central tube. Orals large, excentric.

Column pentangular ; axial canal small.

Distvibntiun, — Niagara group of America.

Remarka. — We only recogni/e Roomer's typical species. Hall's Lamp-
tcrocrimts iiiflalus {Bahmocrlnm sculptus Troost MS.) has never been described,
and the figure * was made from a natural cast, of which the anal side is
not seen. LamjHcrocmus parvus t was also described from very imperfect
nuiterial.

Lumpterocr'mus, by its asynnnetry, and the position of its anal tube, is
very closely allied to Siphonocranta ; but it is readily distinguished by its arm
struuture.

Lampterocrinus tennesseensis Kukmer.

riatc XIII. Figs. 10a, b, c, d.

ISBO. RoEMEli; Silur. Fiiuim West. Tcmi., p. 37, I'late 4, Figs. \a, b.
1881. W. mill Si>.; UcvisioTi I'liln'ncr., I'art II., p. 201,

Syii. JIultiuocriiiiis anilpliis TuoosT (Cutaloguc uaiiip).

Cal^'x elongate, more than once and a half as high as wide, decidedly
asymmetrical. Dorsal cup higher than wide, spreading abruptly to the
middle of the radials, where it attains almost its full width ; cross-section
pentangular. Plates convex, their surface ornamented Avith conspicuous
radiating ridges, passing from the centre of one plate to the centre of an-
other — there being one ridge for each side of the plates — dividing the
surface into well marked, deeply impressed areas. The ridges are angular,
knife-like, their edges more or less serrated ; those from the infrabasals to
the basals, and thence to the radials, and between radials and costals, and
to the first interbrachials, are more prominent than those of the higher in-
terbrachials, but the centre of the latter is raised into a small, sharp node.

Infrabasals five, completely ancliylosod, forming a small cup; the suture
linos obliterated by extraordinary secretion of calcareous matter, and raised
into sharp ridges, passing out from the angles of the column to the lower

• 28tli Rep. N. York State Museum Nat. Hist., Plate 10, Fig. 6.

t 11th Rep. of Gcol. and Nat. Hist. State of ludiaua, Plate 15, Fig. 6.

TIIYSANOCRINIDvE.

209

angles of the basnls ; tho truncated part sharply pentangular, and com-
pletely occupied by tho column. Basals very large, ns long as wide, and
angular above; the posterior one considerably lor^^er, and its upper face
truncated. Kadials fully twice as large as th" first costals, and somowlint
larger than the basals. Second costals smaller i a\ the first, and lacing out-
ward, the sides slightly incurving; their sloping upper faces unecjual, the
shorter side bearing a lateral arm, and the longer one a row of distichals.
Tho higlier orders of brachials, wiiich are roofed over l)y rigid covering
pieces, are formed into tubular appendages, from which at intervals arndets
arc given off alternately. The second arm starts from the third distichnl.
and it is probable that each succeeding arm is given off from the third plate
of successive brachials. The appendages are preserved in the specimens
only to the first palmar. Interbrachials : 1, 2, 3; the first as large as tho
first distichal; those of the second and third row much smaller. Anal side
a little wider and bulging from below the base of the free rays upward-* ; the
anal plate, which is even larger than the first radials, is followed by three not
very large plates, and these by successive rows of three plates each, which
pass into tho anal tube ; the plates of the middle row are marked l)y a con-
spicuous angular ridge, which extends from the angles of the column to the
base of the anal tube, and runs parallel to the ridges upon adjacent radials
and costals. Ventral disk elevated ; composed of few rather large, eon-
■c^x or slightly nodose plates, which are continuous with the interbrachials.
Ihe anal tube is constructed of similar somewhat smaller plates; it is cen-
tral, but bends abruptly to the anterior side of the calyx ; its length not
known. Orals not larger than the other plates of the tegmen ; they are
excentric, being pushed completely to the anterior side. Column near the
calyx sharply pentangular, with a small node at the angles of each joint.

Horizon and Localiti/. — Upper part of the Niagara group ; Decatur and
Wayne Cos., Tenn.

Types in the Mineralogical Museum at Breslau, Germany.

SIFHONOCBINUS S. A. JtiLLER (redefined, W. and Sp.).

1883. Mll-tKB; Amer. ReoloRist, Vol. I., p. 203; and 1SS9, Amer. Genl. and Palirnnt., p. 281.
Syn. Euealyptocrimis (?) — McCiiESXEy, 1850; Dcscr. New Sppcips, p. 95.

Syn. 0/y;)/om»KJ — McCiiesset; Cliicngo Acad. Sci., 1S08, Vol. I., p. 23 ; and Hall, ISfil ; Rop.
of Progr. Geol. Surv. Wise, for 1860, pp. 21 and 23 ; and UaU, 18G7 ; 20th Rep. N. York State
Cab. Nat. Hist., p. 328.

! V

210

THE CRINOIDEA CAMEUATA OF NOHTH AMERICA.

Knuwn only from natural casts and Impressions fVom the natural moulds
in the rock. Calyx large, oblong, its form extremely asymmetrical. Dorsal
cup deeply depressed interradially, the rays projecting so as to give to the
calyx a strongly lobed outline. Ventral disk generally as high as the dorsal
cup ; its posterior side inllated from below the brachial zone to the summit,
forming a conspicuous helmet-shaped protuberance, which at the arm regions
not only occupies the whole width of the posterior interradius, but encroaches
largely upon the left posterior lay, not involving the ray to the right, from
which it is separated by a deep groove. This protuberance, as seen from the
casts, grows narrower at the summit, and the upper part either bonds directly
upwards, in the form of a central tube, or is continued across the summit to
the anterior side, where it opens out to the exterior at — or even beneath —
the arm bases.

Infrabasals five, elongate, variable in form; four of them, as a rule,
angular above ; the posterior one broadly truncate, supporting the first anal
plate. Kadials decidedly angular below. Costals two; ihe first generally
hexagonal. Distichals varying from two to four in different rays, there being
generally two in the anterior rays against three or four in the posterior ones.
The interbrachials, which are numerous and of rather large size, pass unin-
terruptedly from the dorsal to the ventral side of the calyx, and are in
contact with the interambulacrals. The first plate of the regular sides rests
deeply between the sloping upper faces of two radials, its lower angle excep-
tionally touching the basals ; there being two plates in the second row, and
generally three in the third. Anal side wider and larger throughout; the
first anal jdate placed upon the truncated basal, supporting three platt s ''n
the first row, and three or more in all succeeding rows. The ventral surface
of the casts is marked by well defined ridges, converging from the arm bases
to a pentangular, somewhat elevated space behind the anus, the centre of
which is represented by a small cone. These converging ridges are open
grooves or galleries at the inner floor of the disk for the reception of subteg-
minal ambulacra, and the pentangvdar space in front of the anus represents
the peristome, of which the mouth occupies the median part. Anal opening
placed at the distal end of a tube, which is either erect and passes outward at
the summit of the disk, giving to the mouth an excentric position, or is con-
tinued beneath the plates of the disk to the anterior side of the calyx, where
it opens out interradially or interdistichally at — or below — the arm regions.
Ventral disk covered with comparatively large plates, forming a sort of vault,
in which neither orals nor covering pieces can be distinguished.

TIIYSANOCRI lUM.

211

Dhtrthuiiiin. — Only known from the Ni igara group f Americft.

Type of the gonna. — Siphonocrimta aniivniiM (McCht'M.^'v).

lianurks. — TliiH genus, by its iiHyininctricftl form, in closely Allied to
Lamjikrocriiius, from which it differs as stated under that goinis.

S. A. Miller, in proposing tho genus, described it as having tl ipo infr«»
bnsnls. We have examined more than eighty specimens, fiom tUo oolliolionn
of Mr. W. C. Egan of Chicago, and Mr. F. A, Greene of Milwaukee, and
satisfied ourselves that they all have five plates in the proximal ring.

In studying the figures, it must not bo overlooked that most of them
represent natural casts of the internal surface of the test, the plates theiii-
selves having been dissolved by chemical action, and that on these all elevti/-
tions represent depressions of the inner iloor. Only in the figures made
from casts in tho natural moulds does tho surface represent the true external
surface of the plates.

SiphonoorlnuB armosus O^cChessky).
Flute XIX. Fiqs. 3a, h, c.

1S59.
1807.

18S1
18S2.
1888.

Euettlf/ptoerinua armosus — McCiiESNEY ; Dcscr. New Palicoz. Foss., p. 9.5.

(?) tf/jf/j/ofmwjflrMaiKs — McCiiesnky; Trims, Acnd. Sci. Cliicngo, p. 23, Vol. I., Plnte 7, Figs.

Art, b.
(?) Gli/plaater armosus — Vf. mid Sp. ; Revision PaliFocr., I'nrl U., p. I'Jfl.
Gli/iilocrhius armosus — ViwnvXY.i.vi; Gcol. Surv. Wis., Vol. IV., p. 2SI, Tlntc 16, Fig. 11.
SipAonocrinus armosus — S. A. Milleu; Amcr. Geologist, Vol. I., p. H'A.

Syu. Glyptoeriiius siphonatus—\lkU.\ Hep. of Progr., Geol. Surv. Wis., p. 22; mid 20tli Rep.
N. York Stnto Cub. Nat. Hist., Plato 10, Fig. 11.

A large species, only known from internal casts. Calyx subovoid. Dorsal
cup generally higher than the ventral disk, its sides decidedly convex, sub-
globose ; section across the arm bases slightly lobed.

Infrabasals small, forming a shallow cup. Basals as large as the first
costals, the upper angles unusually sharp, exceptionally touching the inter-
brachials. Radials larger than the costals; the first costals laiger than the
second, and hexagonal. Distichals and palmars in series of two each. Arms
four to the ray, their structure unknown. The plates of the regular inter-
brachial spaces generally consist of four rows, arranged : 1, 2, 2, 3 ; tho first
plate as large as the first costal. Anal interradius considerably wider, greatly
bulging from below the arm bases ; the first anal higher than the radials,
succeeded by three plates in the second and third rows, and numerous irre-
gular, rather large plates at the disk. The latter plates together form
a trumpet-shaped inflation, apparently representing a subtegminal anal tube^

212

THK tUINOlDKA CAMKUATA OF NOUTil AMKUICA.

wliieli ciossos tlio mouth, ovoilioH the iippcr pftrt of tho nntcrior nmbuhicra,
mill is c'outiiuiuil .Hiibtc'giiiiiiiiUy all thu way to the tintL'rior nitlc of the calyx,
ovun beyond the arm regioiin, where it bemla outward. The anibu!aera, a«
Keen iVoui iho converging ridgcH upon the castH, vary coimidurabiy in Icngtii
in Homo of tlio rays, tho posterior ones being much longer, especially those
to the left, which are (|uite conspicuously displaced. Tiiu excentric position
of thu mouth, and the irregular arrangement ol' tho ambulacra of this specieM
remind us of the Comatulid genus Actiimintlra.

llurlxiiii (Old Lvculi/i/. — Upper part of Niagara group j Bacine, Green-
field und Waukesha, Wise, and Chicago, Ills.

Slphonoorinua nobllis (Hall).
Flute XIX. Fiijs. la, b, and 2a, b, c.

1801. Glyphn-rlttun mMia — Hall ; Hip. I'mgr. Cicol. Smviy Wise, p. 21 ; ulso 1907, 80lh Hep. N. Yurk

suite Call. Nut. Hist,, I'lnlc 1(1, Kiffs. 9, 10,
18S1. (V) (ll;/i)t„friiiii!i Hcihilia — Vi . iiiul Sp. ; Ilcvislim Pnln'ocr, Port II., p. ISO.
\S'ii. Oli/iiluiriiiHn uiihili.i — WiiiTFlKLU: (icol. Wisconsin, V(i|. IV,, p. iiSi, I'liiti' 10, I''i){s. 9, 10.
ISSS. Sijiliiiiweriiiiiii iiuljilis — 8. A. Miller; Aincr. (Ji'oli)({ist, Vol. I., No. 5, Fijf. 2<i5.

Calyx as large as in tho preceding species, and of similar form ; but tho
ventral di.sk pro[)ortionnlly higher, and the anal tube directed upwards, not
being conducted subtogminally to the anterior side of the cidyx. The orna-
menttition — as observed in gutta percha casts taken from natural moulds
in the rock — is characterized l)y sharp radiating ridges, pas.-^ing from the
centre of each plate to adjoining ones, and presenting upon the surface
of each a well defined stellate figure with a slight elevation in the centre.
A similar style of ornamentation, but less distinct, occurs upon the plates of
the disk and anal tube.

Infrabasals and basals as in S. armosus ; tho latter with sharp upper
angles reaching far up between the radials, and sometimes meeting the first
interbrachials. Costals smaller than the radials. Distichals three, large ;
succeeded by several palmars, which are but little larger than good sized
arm plates. There are four arm openings to the ray, arranged in pairs,
with a shallow depression between each pair, and a somewhat wider and
deeper one between tho pairs of different rays, the latter extending quite
a distance into the ventral surface, and forming deep grooves along the
margin. Arm structure unknown. Interbrachials: 1, 2, 2, 2, 3 ; succeeded
in the disk by comparatively large, less regularly arranged plates, which

, 1

TIIYSAN«KHIMI)^K.

213

coniplt'tcly coviT mouth aiul luiibiiliiom, aiiimiL-ntly without tho iiMMiHtiiiicd ol'
uraU. Aiiiil Huli' gruiitl)' protruihiig, forming lui immciiHu projection, wliich
hcgiuH in the durmil cup, and uxtundM to over onu third of tht! wholu Hur-
Ciicu of thu dixk, giving to thu Mpoeimen an oxcuudingly irreguhir form.
The projection ruMi'inblen an inllatod Mac, whicli toward tiic upper end
grown decitledly Mnndier, and on approaching llie Huiiimit turuM ahrnptly up-
wards in form of a gooil mzed tube. Tiie (IrMl anal plate rcstn upon the
broadly trimcated posterior basal, and \h followed by thrco jdates in the
Hccond, and thrco or more in tho succeeding rows. IntcrdiMtiihalM 1, 2, li;
the lower plate resting upon the upper sloping faces of the second disti(dials.
The inflation upon tho disk, as appears from the impressions, was covered by
n large numl)er of plates without definite arrangement. There were a few
large plates, surrounded by smaller ones, all slightly convex and ornamented
in a similar manner. Mouth oxcentric, marketl in the casts by a stellate
protuberance, from which the ambulacra pass out to tho nrm openings.
Column unknown.

JIurtzon and Luculity, — Same as last.

Siphonoorinus pentagonus w. and Sr. (nov. spoo,).

Plate XIX. Figs. 4n, h.

A Icrge species, of the type of ^S". vohlVis. CaUx decidedly asymmetrical,
about as high as wide, strongly lobed at tho nin regions; tho depressions
deep and wide. Posterior side of the calyx enormously inlhited from the top
of the anal plate to tho summit of the disk, tho bulging involving the left
posterior ray, which projects more conspicuously than the others. Dorsal
cup obconical, the sides evenly sjircading to the top of the costals, thence
more rapidly to the arms. The upper angles of the basals and lower angles
of the interbrachials more obtuse than in the preceding species, and never
in contact. Radials, costals, and interbrachials of nearly uniform size ; the
first costal somewhat larger than the second. The first distichal as large as
the upper costal, the two following considerably smaller, the succeeding ones
free arm plates. Arm structure unknown. Interbrachials 1, 2, 3, followed
by interambulacrals. The nnul plate is succeeded by three and four plates,
the latter supporting the plates of the anal protuberance, which on approach-
ing the top of the disk contracts rapidly, and turning abruptly upward, forms
a tube at the summit. Ventral disk one fourth shorter than the dorsal

214

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

cup; the moatb quite excentvic, and the posterior ambulacra considerably
longer.

.Uorizon and Locality. — Same as last.

Ti/jye in the collection of W. and Sp.

Rtmwks. — Th\i species is readily distinguished from the preceding
species by having but two arms to the ray from the calyx, which, however,
may branch in their free state.

RHODOCRINIDiE Roe^her (1855).

DiCYCLIC. LOWEU BRACHIALS AND INTEBBRACIIIALS FOBMING AN IMPOniANT PART OP
THE DORSAL CUP. RaDIALS SEPARATED ALL AROUND BY AN INTERRADIAL PLATE
WHICH IS FOLLOWED BY WELL-DEFINED, REGULARLY ARRANGED INTERBRACUIALS.

Analysis of the Genera.

Infrabasals 5. Basals 5.

A. Anal intekradius oknerally with additional plates.

1. Arms uhiserial.

a. Arms not branvhing.

Basals oxposcd in a side view Ehaphanocrinus-

2. Arms hiserlal.

a. Arms hranchhKj.

Calyx obovate • anus without a tube ; interbrachials
numerous, two in second row ; interdistichals gen-
erally present Arch^ocrinus.

Calyx depressed globular, anus at end of a tube, first
interradials frequently separated from basals by
supplementary pieces. No interdistichals. Arms
probably given off from brachial prolongations of

the calyx Diadolocrinus.

Calyx globose, flattened or concave below ; two or three
interbrachials in second and succeeding rows ; no
interdistichals.

Ventral disk narrower than dorsal cup . . , Ehodocrinus.
Ventral disk equal to, or exceeding dorsal cup ;
tubular appendages suspended from mar-
gin of disk Gilbertsocrinus.

b. Arms not branching.

Calyx globose, arms long and heavy ; interdistichals

numerous TnYLAcocRiNUs.

B. Anal interradius without additional plates.
1. Arms biscriol.

a. Arms not brnnchinfj, dorsal cup broadly truncate at the bot-

tom, radials sometimes not all separated; arm facets

directed upward Lvriocrinis.

b. Arms branching.

One costal ; interdistichals few Antiiejiocrinus.

Two costals ; rays produced into long trunks giving off

armlets from opposite sides Eipidocrincs.

C. Anal interradius unknown.

Arms uuiserial, branching frequently ; infrabasals very small . Diamenocrinus.

W -i\

216 THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Geological (mil Geo(jraj)hical Distribution,

Number of known species.

(Open figures indicate Anicrieau, those iimiked ( ), European.)

Formation.

Khodochiniu.e.

1
1

1
g

American.

1 ^

■<ww

■c

§
1

s
•E
§

J
"P.

3
C

•c

3
u

Keokuk.

If
^5

Upper Burlington.

0"')

(4)

Lower Burlington.

^ , ^

Kinderliook.

3 1

Hamilton.

Up. Devon.

(2)

_(2)_

(1)

Upper Ilelderberg.

Eifel bed.

Niagara.

Wenlock.
Gotland.

•*

(2)

Hudson Itivcr.

Trenton.

1
2

4
4

2
2

(4)

Total species 34 | '.L

1
(2)

2
(1)

(2)

(1)

licmarks. — When Roemer established the Rhodocrinida}, he was ac-
quainted only with the genus Rliodocrinus, in which he included also the
sjiecics which were afterwards referred to Rlpidocriims and Gllhertsorrinm.
He omitted Acaiithocrimis, which he had himself proposed in 1850, probable-
having discovered its identity with Bhodocrinm.

The earlier French writers, d'Orbigny, de Koninck, Pictet, and Diijardin
and Ilupd, placed Ithodocrhms with the Cyatliocrinidoo.

The Rhodocrinida? of Zittel and de Loriol embrace Rliodocrimts, OU/i-
crinus, Acanthocrhnis, Ripklocrinm, Iladrocnmis, Tri/hliocrhms,* and Thi/sano-

• Wo Imvc not seen Geinitz's description, but judge from Zittel (llandb. der Palieont., Vol. I., p. 377)
that it is a do\ibtful ur imperfectly defined genus.

RHOUOCRINID^,

217

criniis. S A. Miller in 1889 added Lyriocrinus, and adopted Lyon's name
Gotiiasteroidocrimts in place of OUucriinis. He amended this in the following
year by leaving out the monocyclic Iladrocnniis, and adding Arcliwocrbms
and Raplumocrituis.

To the genera which we arranged under this family in 1885,* we add the
genus Dlaholocrlnm, which we have proposed for a species that had been
previously referred by us to Arclueocrinus.

The Rhodocrinida3 are nearest related to the Thysanocrinida;, but are
readily distinguished by the complete lateral separation of the radialsf by
the interradials ; the radials of the ThysanocrinidoD being in lateral contact
except at the anal side. The marked asymmetry in the ventral disk, so
characteristic of the latter family, is not ob-
servable in the Rhodocrinida?, in which the
whole calyx, as a general rule, is remarktably
symmetrical.

The family has a great stratigraphic range,
extending from the Lower Silurian to the
middle of the Carboniferous and becoming
extinct in the Keokuk group. The ancestral
type is probably Archwoerinus in the Trenton
group, of which Diuholocrimts is an offshoot.
The evolution of these forms through Lyrio-
rrbius in the Niagara, lliylacocrinus and R'qn^
(locrinus in the Devonian, to the profusely

developed Rhodoci-lnus in the Carboniferous, is by easy gradations. Nor
is the step from Bhodocriiw^ to the highly specialized Gllhertsocrimis a
difucult one, because there are transition forms in which the characters of
the two genera are to a great extent merged. Raphanocriinis in the Trenton,
and Anthemocriniis from the Upper Silurian of Gotland, apparently repre-
sent variations toward the Thysanocrinida).

The Rhodocrinidae are by far the most important dicyclic family of the
C.amerata, being composed of ten genera and fifty-four species, of which
thirty-six are from America, and eighteen from Europe.

• Revision, Part II., pp. 96 to 99. (Proceed. Acad. Nat. Sci. Pliila., pp. 318-321.)
•)■ There, is an occasional exception to this in the genus Lyriocrinm, wlierc tlie rndinls arc sometimes
connected by a narrow strip, except at the anal side. This occurs (piile frequently in L. iliwli/lm from tlie
Niiij^iira of New York ; while in L. melissa, L.jiivenis, and an undcscribed Li/riocriiius from Dudley, England,
the radials are widely separated.

Fig. 10 — Rhodocrinus.

i M

g B ? jmBL— ■ J ' LSJW^ BWWfwegBBgMgi'

218

TIIK CRINOIDKA CAMP:RATA OF NOHTII AMKKICA.

I ' I

In the ilcscriptions of the RliodocrinicloD, tlie. plnte which is interposed
between tlie radials is called tlu* first inteiradial as a matter of convenience,
and those following it in the dorsal cup interbrachials, although, as elsewhere
explained, they all belong undoubtedly to the same system of plates.

RHODOCRINUS Miller.

1821. Miller (in pnrt) ; Nut. Hist, of the Criiioidcn, p. lOfi.

1S35. Agassi/.; Mem. Hoc. Sci. Ncucliiil., Vol. I., p. 196.

1841. MCller (in iiail); Moimtsber. <i. llcrliii. Aknd., p. 209.

1S43. Austin; Ann. unci .Mag. Nut. Hist., Vol. X., p. 109.

1830. D'Orhigny; Proilr. do Paleont., Vol. I., ji. 104.

1S33. Dr. KoNlxcK nnd Lk Hon (in pnrt); Uoclipr. Grin. Carb. Bclg., p. 103.

1853. lloKMER (in part); Loth. Gcogn. (Ansg. 3), p. 240.

1855. (?) MCi.LER (Wirtgcn nnd Zcilci); Vcrli. Nntnrliist. Vcrcin f. Rliciiil., Vol. XII., p. 11.

1857. I'icTET; Tiaile do l'al6ontologio, Vol. IV., p. 314.

1858. ll.KU.; Gcol. Hep. Iowa, Vol. I., I'aH II., p. 550.
1861. Hall; Host. Jonrn. Nat. Hist., Vol, VII., p. 322.

1868. Meek and Woktiien ; fiool. ]{pp. Illinois, Vol. III., p. 476.

l'>75. Grenfeli. ; Proceed. Bristol Naturalists' Soc, Vol. I., Part III., p. 480.

1879. Zittel; llandb. d. Pnln-ontologic, Vol. I., p. 376.

1881. W. and Sr.; Kovision Paliener , Part II., p. 209 ^Proceed. Acad. Nat. Sci. Pliila., p. 383).

1883. WoRTllKx; Gcol. Kcp. Illinois, Vol. Vll., p. 303.

1883. Quexsteut (in ]iarl) ; Handb. d. Potrefactonknndc (Ausg. 3), p. 958.

1889. W. and Sp. ; Gcol. Rep. Illinois, V<d. VIII., p. 180.

1889. S. A. Miller; N. Amor. Gcol. and Palicont., p. 277 (not Fig. 417).

(Not KhoiloerhiH.i Golilf., 1826, Petrel". Gennaniie, A'ol. I., p. 212; nor McCoy, 1844, Cnrbonif.

Foss. Ireland, p. ISO; nor V. Roomer, 1S51, Verb. Natnrli. Vcrcin f. Rheinl., Vol. VIII.,

p. 358; nor Billings, 1859, Geol. Rep. Canada, Decade IV., p. 61; nor Lyon, 1861, Proc.

Acad. Nat. Sci. Pliiia., p. 409 ; nor Hall, ISfiS, Trans. Albany Inst., Vol. IV., p. 198, and 1876,

1st edit, of 2Sfb Rep. N. Y. State Mus. Nat. Hist., p. 139; nor SchuUy.c, 1867, Mon. Eeliin.

Fill. Kalkcs p. 53; nor White, 1880, Proc. United States National Mns., p. 259.)
Syn. Acanthorriiim F. Roemer, 1S50. Nencs Jalirb. f. Min-^ralogie, p. 79 ; Miillcr, 1853, Vcr

bandl. Naturb. Verein, Vol. XII., p. 8; Hall, 1862 (Subgenus of Rhoihcrinus), 15tb Rep.

N. Y. State Cab. Nat. Hist., p. 125.

Calyx more or less globose, the dorsal cup generally somewhat flattened
r concave at the base, and constricted in the upper part. Plates flat or
convex, nodose or spiniferous, their surfaces smooth or striated. Infrabasals
five, smnll, sometimes merely occupying the bottom of the colunmar con-
cavity. Basals five, large, all truncated at the upper end. E^tdials, as a rule,
larger than the costals, but smaller than the basals. Costals two, not unfre-
quently coalesced, so as to form practically a single plate, Distichals free in
part ; rarely more than one, and never exceeding three, take part in the
calyx. Arms arranged in pairs and bifurcating; biserial, either directly from
the calyx up, or from the last bifurcation ; joints short ; the pinnules in
contact. The first interradial plate is followed by several rows of inter-

I'! H

RIIODOCRIXIIXE.

219

bracliials, the second row consisting eitlier of two or three pieces. When
there are two plates at the reguhir sides, tiie anal side has always throe, but
when the former has three, there is no additional plate at the anal side.
Ventral disk narrow, rising but little above the dorsal cup ; composed of
irregulorly arranged plates, none of which can bo recognized as orals. Disk
ambulacra subtegminal. Anus excentric, sometimes marginal. Column
round; the axial canal pentagonal or stelliform; the internodes frequently
consisting of but one joint.

Distribution. — Ehodocrinus first appears in America in the Hamilton
group ; it attains its climax in the Kinderhook and Burlington beds, and
becomes extinct at the end of the Keokuk epoch. Specimens, as a rule, are
rare. In Europe the genus occurs in the Jl/ieinisch Ueherijanrjsfjchinjc, and it
is represented by several species in the Mountain limestone.

Type of the genus : Ehodocrinus vents Miller, from the Carboniferous of
England.

Bemarks. — Rhodocrinus verus, according to J. S. Miller, occurs in the
Mountain limestone of Yorkshire, and also in the Wenlock limestone of
Dudley, England, and it was said to have three basal ])lates. Miller con-
founded two very different types, which have since been recognized as
distinct genera. Tiie Carboniferous form, which took Miller's specific name,
is universally regarded as the type of the genus Jihodocrinus, having five
infrabasr.ls instead of three, and biserial arms ; the Silurian form from Dud-
ley, with three infrabasals and single arm joints, was described by Phillips as
Sagenocrimts expansus.

The genus lihodocriniis, as we understand it, includes species with smooth,
nodose, and spiniferous plates. For a certain species with spinous plates
from the Devonian, Roemer proposed the genus Acaiithocrinus. We have
carefully examined the figures of A. longispinus, as given by Wirtgen and
Zeiler,* but have failed to discover any characters by which this form can
be separated even subgenerically. Spinous projections on the basals and
radials occur quite frequently also among Carboniferous species in all possible
variations. It is possible that " Rhodocrinus gonatodes " Midler belongs to
Oehlert's new genus Diamenocrinus.

We have referred Rhodoerinus microbasiUs and R. pyriformis, both of
Billings, to Archwocrinus ; R. vesiKralis White to Diabolocrinus ; R. melissa
Hall to Li/riocrinus ; R. Hcdli Lyon to Thi/sanocrinus ; R. stcllaris de Koninck

• Verb. d. Naturbist. Vcrein, Jabrg. XII., Tab. II.

220

THE C'KIXOIDEA CAMEKATA OF NORTH AMERICA.

and Le Hon to GUbertsocrinvs. Tlie following species are too little known to
be recognized : li. spinosm Hall, li, (jradlis Hall, R. varsoviensis Hall, and
It. rectus Hall.

RhodocrinuB Wortheni Hall.
Plate XL Fig. G, and Plate XII. Figs. 7a, b, c.

1858 IUli-; Gcol. Rep. Town, Vol. I., Part II., p. 556, Plato 9, Figs. 8a, b, e.
18S1. W. mid Sp. j Ilevisioii Pulteocr., Part II., p. 213.

A small species. Calyx depressed-globose, a littlo concave at the bottom;
plates delicate, flat and perfectly smooth. Infrabasals of moderate size, the
tips slightly projecting beyond the column ; forming a pentagon. Basals very
large, a littlo wider than long. Radials nearly as large as the basals, angular
below, narrowly truncated above ; their lateral faces parallel. Costals two,
generally anchylosed, the two together smaller than the radials, and only
half their widtii ; the first quadrangular. Distichals 2 X 10 in the calyx,
those of the lower row nearly as large as the costals, the upper smaller, and
excavated to form the arm bases, which do not project. Ambulacral open-
ings small, slitlike, directed upwards, and arranged in pairs around the disk.
Arms delicate and cylindrical ; they branch twice above the calyx, and are
nniserial to the first bifurcation, then turning into biserial, with short inter-
locking pieces. The five plates interposed between the radials are consider-
ably smaller than the basals, and but littlo larger than the two succeeding
interbrachial.s, which are followed by two rows of two .small plates. At the
anal side, the first interradial plate is larger than those of the regular
sides, and followed by three plates. Ventral disk very small, and following
the general curvature of the calyx. Column small, round ; the upper joints
rounded at their edges ; the axial canal minute.

Horizon and Loca/if;/. — Lower Burlington limestone, Burlington, Iowa.

Ti/pe in the Illinois State collection, Springfield.

Remarks. — Specimens apparently of this species, are found in the
Waverly group of Cuyahoga Co., 0., as natural moulds ; the caly.x, however,
appears to be more depressed, and larger in proportion to the length of the
arms. Similar specimens, but decidedly more urn-shnped, occur in the
Burlington beds of Lake Valley, New Mex., for which we propose the name
Rhodncrimis Wortheni, var. iirceolatus (PI. XII. Figs. 8, 6). The typical form
resembles R. ivatersianus W. and Sp., and R. Wachsmuthi Hall ; from which

4 r

RIIODOCRlNIDiE.

221

it differs in the mode of branching of the arms, and the fact that the latter
has convex calyx plates; also in its basal concavity being much deeper,
the column larger, and calyx higher.

Rhodooriiius Wortheni, var. uroeolatus W. and Sp.
Plate XII. Figs. 8a, b.

Differing from the typical form of E. Wortheni in the form of the calyx,
which is urn-shaped instead of globular, higher than wide and rounded at
the bottom, while that is flattened. The infrabasals are convex, and on
a level with the basals. The greatest width of the calyx is across the first
costals, whence it contracts rapidly to near the arm bases, which slightly
project outward, giving to the tegmen a decidedly pentangular outline.
Ventral disk almost flat, wider than in the typical form, and the plates less
numerous. Anus subcentral, and not protuberant. The plates of the calyx
flat and without ornamentation.

Horizon and Locality. — Age of the Lower Burlington limestone, Lake
Valley, New Mexico.

Types in the collection of Wachsmuth and Springer.

Rhodoorinus watersianus w. and Sp.
Plate XII. Fig. 9.

1889. W. and Sp. ; Geol. Rep. Illinois, Vol. VIII., p. 184, Plnte 17, Fig. 16.

A small species ot the type of Rhodocrinus Wortheni, from which it differs
in the more concave base, the proportionally smaller size of the basals, in the
more elongate form of the calyx, and in the arm structure. Calyx from
sub-globo.se to sub-ovoid, truncate at the bottom and narrowly concave ;
plates very slightly convex, and without ornamentation.

Infrabasals small and concealed by the column. Basals moderately large,
their lower ends abruptly deflected inward, their upper portions curving out-
ward and upward. Radials somewhat smaller than the basals; as wide as
long. Only the proximal distichals take part in the calyx ; they are followed
by five to six slightly cuneate free plates, of which the upper one is axillary,
and supports two arms, which remain simple. Arms twenty, rounded on the
back, slender, very little tapering, and biserial from the last bifurcation ; the
joints moderately high and a little convex. Pinnules stout for the genus.
The first interradial plate as large as the radials ; followed by five to six

222

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

interbrachials in two or tliree rows. Tlie nnal side lias tlie same number of
Interbrachiul.x, but thoHO enclose a longitudinal row of three ratlier large anal
plates. Ventral disk small, somewhat receding from the dorsal cup, produc-
ing nn offset or groove around the margin ; it is convex, and composed of
small irregular plates. Column circular; the joints rounded at the edges;
the nodal joints a little wider and higher. The internodes at about three
inches from the calyx consist of six pieces, and the same number apparently
persists throughout the rest of the colunui. Like most of these stems, it
tapers considerably downward, and near the distal end is provided with com-
paratively stout cirri or rootlets, irregularly given off from the sides.

Horizon and LocaVitij. — Kinderhook group, Le Grand, Marshall Co., lown.

Ti/pcs in the collection of Wachsmuth and Springer.

Bhodocrinus ooxanus Woktden.
Plate XIII. Figs. 6 and 7.

1883. Wortiikn; Gcol. Kcp. Illinois, Vol. VII., p. 305, Plate 28, Fig. 7.
1385. W. and Sr. ; Kcvision riiUeocr., Part III,, p. 99.

Syn. Rhoiloeriiius poli/ildclglm Wohtiien; 18S3, Gcol. Kcp. Illinois, Vol. All., Plate 27, Fig. 5.

The two specimens figured by Worthen as Ithodocrinns coxanus and
li. 2)oli/dactyhis are too much crushed and distorted to admit of critical com-
parison or satisfactory description. Both appear to have smooth plates, and
the.se, so far as we can ascertain, are arranged substantially in the same
way ; but R. ])ohjdaci>/hi,% according to Worthen's figure, has an additional
bifurcation in one of the ray divisions, i. e, five arms to the ray. Whether
this is a persistent character cannot be ascertained from the specimens,
and until this is proved we prefer to regard i?. 2>ohidactylus a synonym of
E. co.ranus.

Horizon and Locality. — Upper part of the Geode bed in the Keokuk
group ; Hamilton, Ills.

Types in the collection of L. A. Cox of Keokuk.

Bhodocrinus Wachsmutbi Hall.
Plate XIII. Figs 5a, h, c, d, and Plate XV. Fig. 7.

1861. Ham,; Piclini. Dcser. of New Spec, of Crinoidea, Ail)any, p. 18.
1881. W. and Sp.; Uevision Paloeocr., Pt. II., p. 213.

Somewhat larger than the three preceding species. Calyx snbovoid,
flattened at both poles, the proximal end abruptly and deeply impressed.

RIIODOCRINID.E.

228

forming a circular pit, which is but partly filled by the upper joint of the
column. PlatcH without ornamentation, a little convex, the suture lines
slightly grooved.

Infrabasals small, concealed by the column. Basnls as large, or even
larger than the radials, their lower ends bending abruptly inward to take
part in the pit, the upper portions curving gently outward and upward.
Radials heptagonal, a little wider than long, and twice as large as the
costals, which are (luite narrow. Distichals free from the first up ; the
upper faces of the latter slightly excavated to form the ambulacral opening.
The free distichals consist of about eight plates, which are very short; the
upper one axillary, supporting two arms, of which one branches again on
the eighth joint, while the other remains simple. Arms cylindrical, of nearly
uniform size, biserial al)0ve the last bifurcation ; the plates very short and
transversely arranged. Pinnules rather stout and in contact ; the joints
twice as long as wide, with deep ambulacral grooves. Interradial areas not
depressed ; arranged : 1, 2, 3, 2, succeeded by three or four more pieces.
The anal side has three plates in the second row. Ventral disk composed of
but few plates ; it is .somewhat elevated nt the margin, almost flat in the
middle. Orals well defined ; surrounded by two rows of rather large inter-
ambulacral pieces, which meet with the interbrachials. Anus subcentral,
opening through the disk. Column round ; axial canal small and stellate.

Horizon anil Locality/. — Lower Burlington limestone, Burlington, Iowa.

Tyj)e in the Museum of Comparative Zoology, Cambridge.

Rhodoorinus Whitei Hali,.
Tlate XIII. Figs, la, 6, c, and Plate XV. Fiys. 6a, b.

1861. Hall ; Description of New Spec. Criiioids, p. 9.

1861. Hall; Host. Journ. Nat. Hist., Vol. A'll., p. 324.

1872. Hall; N. Y. State Mas. Nnt. Hist., Bull. I., Plate 6, Tigs. 19, 20, 21.

1881. \V. ami Sp. ; Revision Palreocr., Part II., p. 21.3.

Syn. Rhodocrinm ll'liilei, vnr. biirliiifftoiicnsu Hall ; 1861, Bost. Journ. Nat. Hist., Vol. VII., p. 32.5.

The largest known American species. Calyx depressed sub-globose, a
little wider than high ; the lower portion flattened and formed into a deep
concavity ; the sides decidedly bulging to the first costals, then contracting
to near the arm bases. All plates of the dorsal cup to the top of the cos-
tals of nearly the same size, all strongly convex, and without ornamentation.

Infrabasals of medium size, slightly projecting beyond the column. Bas-

224

THE CIUNOIDEA CAMEEATA OF NUKTII AMEUICA.

Ills large, lying aliiiOHt liorizontiiUy, except their proximal endH, wliicli bend
abruptly inwartl luul take part in tlie concavity ; the upper facen broadly
truncated. Radials liexiigonal, about as wide as long. CoMtals aH long as the
rrtdialx, but generally a little narrower. DisticlialH generally repreMcnted by
only one row of plates in the calyx, which are excavated at the upper faces
to Ibnn the arm openings, of which tiiere are two to the ray. Nothing is
known of the arm ■itructure. The interradial spaces are occupied by 1, 2,
3, and two large plates, followed by two or three sniallcr ones. The
anal interradius has a lew more plates in the upper rows. Ventral disk
small, slightl}' convex, pentangular in outline, and composed throughout of
small, irregular, slightly convex pieces, which increase in size as they ap-
proach the arm regions. Anus subcentral, at the end of a short tube or
elongate protuberance, which gives to the disk an irregularly conical form.
Column small, not filling the basal concavity; it is round, and there is an
alternation of larger and smaller plates. Axiiil canal of medium size and
stelliform.

Ilorhon und Locality. — Lower part of the Lower Burlington limestone,
Burlington, Iowa.

Types in the University Museum at Ann Arbor.

Remarks. — We have examined a number of specimens of this rare
species, including the types, and are of the opinion that the specimen
which Hall described as var. hurVinfjtimensls is a very large example of
R. Wliltei. That it has one or two additional interbrachials, that the
calyx is proportionally a little shorter and the basal concavity deeper, is
readily explained by extravagant growth. The species occurs in the low-
est layers of the Lower Burlington limestone, and the calyx sometimes
attains a size of two inches in diameter.

Rhodocrinus Benedioti s. A. Miller.

1892. Advance Sheets Eighteenth Rep. Geol. Survey Indiana bj Gorby, p. 15.

Calyx small and globular, except the tejijmen, which is slightly conical.
Dorsal cup nearly as high as wide, widest at the middle ; the sides evenly
rounded to the arm bases ; the base concave. Plates convex, some of them
angular, and the principal ones covered with radiating ridges. Suture lines
distinct.

Infrabasals .small, forming a flat pentagonal disk. Basals the largest
plates of the calyx, highly convex in the central part, with ridges extending

HlIOUOCiUNlU.E.

225

to adjoininjj plates. Hiuliiils nearly as larj^o as the basals, but the ritlj^es less
conspicuous. First costais smaller tiiun the second, convex ; the second as
largo a.s tho lirst. 'I'hc second distichals support the free arms, which are
not preserved. Interradiiil areas not depressed below the level of adjoining
brachials ; composed of the intcrradial plate, and about nine interbrachials,
of which tho upper ones are very small. The anal area has one or two
additioiud plates. Ventral disk small ; its diameter scarcely two thirds the
width of the dorsal cup at the widest part; composed of numerous very
small, highly convex plates. Anus subccntral. Column round.

Horizon and Locullhj. — Keokuk group ; Harrison Co., Indiana.

liemurlcH. — We did not have access to tho specimens to illustrate this
species, and were obliged to make our description after Miller.

RhodoorinuB nodulosus Hall.
Plate XIII. Fi(j. S.

1802. RMnmiiii.' (.■Ii-rii/fhrriiiii>) iio(/iilo.iii.H — IIali.; ]5I1i Itrp. N. Y. Stntc Cab. Nnt. Hist., p. 120;

il)iil., 1872, Hull. I., rialc In, Vlfi. 8.
1881. Rhodocrinm iiodiitumia — W. ftiij Si". ; Uevi.'.ioii I'nlieocr., Part II., p. 212.

Of medium size. Dorsal cup more rapidly .spreading to tho top of the
second costais than from there to the arm bases ; height and greatest width
about equal; interradial and interdistichal spaces depressed. Plates convex,
the surface covered with obscure radiating ridges, and the central jiortion in
most of them produced into a small node.

Infrabasals small, but plainly visible beyond the column ; the bottom
somewhat depressed for the reception of the column. Basals larger than
any of the other plates, longer than wide ; the lateral upper faces longer
than the lateral lower ; the upper faces rather narrow. Radials larger than
the costais ; three of them pentagonal, the two posterior ones hexagonal ;
the costais slightly narrower and shorter. The distichals support the free
arms ; five to six of them take part in the calyx, of which the three lower
ones are subquadrangular and twice as wide as long, the two or tinee suc-
ceeding ones cuneate, and .^ilightly interlocking. The free distichals are less
convex and shorter than those of the calyx ; the succeeding arm plates
strictly biserial, and very short. Arms rather stout at the proximal ends, but
the size decreases rapidly with each bifurcation. There are two bifurcations
in the free arms, and the branches are widely divergent. The large plates

mi':

236

TIIK (UINOIDKA CAMKRATA OF NOIITII AMKHICA.

I ^

iiitorpoMod bi'twoi'ii the rft<liiiln iiiv IoIIowcmI l»y two, tluoi', and tliroo Intcr-
hiacliiiilM lit tlio ri'giiliir .xidi-s ; wliilo tliK aniil h'uIi' has throe in tlio weeoinl
niid luiii' ill tiie third row. Cuiisti-iictioii of ventral disk uiid iinim nut i\nu\vn.
Intura.\illarieH tlnee or more.

Jliirix'in and Loiuliti/. — Hamilton groiiii ; C'anandaigua lUid Ontario Cos ,
N. Y.

I'l/jir in tlic New York Slate Cabinet jf Natural IIi«tory at Albany.

lidiiiii'kn. — Tiiis form dill'ers from the otiier Anieriean species, except
lihinhirrliuiH Kirhyi, in having inleraxillary i)lates, and also in the details
of tho arm Htructurc. Our description was made from Hall's figure, ami
from ft specimen in tho collection of Prof. J. M. Clark, which ia now in tho
New York State Cabinet.

Rhodoorinus Kirbsri W. and Si-.
rhttc XII. Fi,js. I(t, h, c, d.

188',». Ocol. Rep. llliiiiiis, V(,l, VIII, p. ISO, IMiilc 1.5, Fig. 10 ami riiite 10, Fi« 3.

Calyx barrel-shaped, a little longer than wide, excavated at the bottom,
slightly swelling from the middle of the ba.sals to the middle of the second
costals, thence contracting to the margin of the tegmen. In some specimens
the sides are almost cylindrical. Surface of plates convex, covered with
obscure ridges passing from plate to pinto ; those following the radial series
somewhat stronger, and increasing in prominence as they approach the nrin
bases, so as to give to the calyx an obscurely pentangidar outline.

Infrabasals concealed by the column, small, resting within a .shallow con-
cavity. Basals large ; their lower margins abruptly bent inward ; the
middle portion forming a sort of rim on which the calyx rests. Kadials
smaller than the basals, about as wide ns long. Costals two, of nearly
iniiform size, about half the size of the radials. Disticlmls five; the t\. o
lower ones incorporated into the calyx, smaller than the costals; the three
upper ones free, very short and rounded exteriorly; the third axillary,
giving off two branches, of which only the inner one branches again, gener-
ally from the third plate, giving three arms to each main division of the ray,
or thirty in all, with occasionally an additional arm in one or both posterior
rays. Arms cylindrical, and only tapering nt the tip,i; they are composed
of a double series of rather short, interlocking pieces, with indented suture
lines which give to the back of the arms a file-like appearance. Pinnules

HIIODOCHIXID.K.

227

Mtrong, contiguoiiM ; compoHi'd of t'l<)tij,'iite juiiitn. Intcrnulial spaces nnaiij^id
in four rows. Tlic plates iiilorpo^ed l)utweeii tlie rutlials Hinalli'i' tliaii tlu-MO ;
followud by two, nuely three, iiiterbnicliiulH, iiiul tlier-o hy two and lliit'e
otlierM in tlio two Miiceeeding rowM, wliieli gradiiiilly decrenHe in sizt' iijiwardH.
Aniil Mido wider, witli tiired plates in the Hecond, imd f^encrally lour in the
thinl row. Interdistichais from two to three, very Minall. l)i>k fijij^htly
convex, the iulerriidial spaces a little depressed ; constructed throu>;hout
of very small, irregularly arrangeil tumid plates. Anus nimost centrid. at
the eml of II wart-like, somewhat conical prolrberance, composed of very
smidl pieces, Colunni roiuid, from eight to ten inches long, nearly uniform
for ahout two thinls its length, whence it gnuliially tapers to ii line point,
witli a few sliort cirri given oil' toward the end. The joints are rounded
along their edges, and the nodal ones nro a little the wi<lest and longest.

Horizon and Locdii/ij. — Kinderhook group, Lo Grand, Marshall Co ,
Iowa.

7}/j)rs in the collection of Wnchsmuth and Springer.

Jiinnirkfi. — This species is one of the most al)undant at the Le Grand
locality, where many specimens have been ol)tained with crown and stem
fully preserved. The specimens arc invariably of a very dark color, though
lying in contact with I'lnfi/crlniis and other forms which are light colored, —
sometimes almost as light as tiiose from the Burlington r<)i'l<s. 'i'his varia-
tion in color of the fossils is one of tlie interesting facts of that locality. The
Crinoids must have been deposited there in very quiet waters ; they occur
in a soft, light bulT limestone, and in many cases are imbedded just as they
died. They occur in nests or colonies, and the genera and sj)ecies are indis-
criminately commingled, there being of Crinoids and Blastoids upwards of
twenty-four species. It is therefore a singular fact, that while the specimens
of some species are of a pure calcareous composition, and of very light color,
those of others, under precisely the same conditions of fossilization, lying
side by side with them and often with stems and arms intertwined, are
harder, and of a very dark, brownish or even purplLsli grey color. The
contrast between some of tliem is very marked, and so nearly constant for
the species as to be quite a reliable feature for separating them. There are
intermediate shades of color between the lightest and the darkest, but as
a general thing specimens of the .same species have a uniform shade. As
a rule, all the species of Arthiocrums, Platycrinus, Graph tocrlmis, Scaphlocr'iHus,
Taxocrimis and the Blastoids, are of light color ; Dori/crims and Dichocriiwfi

228

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

. i

] i

are dark, and Majlstocrhms and Bu'ocrimts rather intermediate ; but while
llhuducrinua Kirbiji is very dark, R. nanus is liyht colored, and li. water-
sianus intermediate between them.

Rhodocrinus nanus M. and AV.

Plitic XL, Fi<js. 7a, h ; and Plate XII., Firjs. 2a, h.

1800. Mkkk iiiul WoRTiiEN; Proceed. Acad. Nut. Sci. Pliilu., \i. 251-.

1808. Mkkk and Wobtiikx; GcoI. Surv. Illinois, Vol. 111., p. 470, Plate IS, Figs. 2a, b.

1885. W. and Sp. ; llcvisiou Palicocr., Part 11., p. 212.

1859. AV. and Si'. ; Geol. Siiiv. Illinois, Vol. VIH., p. 182, Plate Ifi, Fig. 4; and Plate 17, Fig. 15.

S>u. Rhuihi-riiiHs seiilptiis S. A. JIiLLEii; 1890, Uescr. New Genera and Species of Ecliin., p. 42,
Plate 7, Fig. 11.

Svn. lUwilwriiiiis ctrluliis S. A. Mii.i.ER; 1890, ibid., p. 43, Plate 7, Fig. 10.

Calyx siibglobose, the side.s regularly convex, except in specimens with
very protuberant basals, in whicli they appear to be nearly straight ; the
base triuicate and slightly impressed. The plates along the rays marked by
rounded ridges, which vary somewhat in prominence. These ridges in some
specimens are confined almost entirely to the radial series, giving to the
calyx a pentagonal outline, but in others they run to the basals, interradials
and anal plates, traversing the sutures, and pa.ssing from plate to plate. The
plates are more or less convex, and their outlines well defined.

Infrabasals small, im[)ressed, slightly projecting beyond the column.
Basals large, a little protuberant, the calyx resting on their lower margins,
which are rounded and form a low rim around the concavity. Radials nearly
as large as the basals ; the costals about of equal size, but one third smaller
than the radials. Distichals generally five, of which only the first and
larger one takes part in the calyx ; the others which are of nearly uniform
size and quadrangular, except the upper which is axillary, are free arm
plates. The inner branches of the arms divide again on the third joint, and
there is also occasionally a bifurcation from the outer branch in a posterior
ray. The arms taper but little, are long, and biserial after the last bifur-
cation. The arm joints are narrower than in R. Klrhyi, and their backs more
rounded ; the pinnules stronger and less closely packed than in that species.
First interradials half the size of the radials ; followed by two interbrachials
nearly as large ; the succeeding plates considerably smaller, and their ar-
rangement somewhat irregular. Anal interradius wider than fhe others, and
enclosing a continuous row of anal plates, which rest upon the truncated
upper face of the interradial. The first anal plate is as large as the radials,
but the interbrachials at both sides of it are smaller than the corresponding

RHODOCRINIDiE.

229

plates of the other areas. Anal opening exccntric, directed upwards, placed
within a large protuberance, composed of rather large plates. Ventral disk
convex, depressed at the interradial spaces, and constructed of small, irre-
gular, convex pieces without definite arrangement.

Horizon and ioca%. — Kinderhook group; Le Grand, Marshal Co., and
Burlington, Iowa.

Types in the Museum of Comparative Zoology at Cambridge, and in the
collection of Wachsnjuth and Springer.

Jiemarks. — This species is nearest allied to E. Kirliji, from which it is
distinguished by its more globose form, more slender arms, by the ridge-
like series of anal plates, and the absence of interaxillaries. In the Le Grand
beds this species is readily identified by its color, which is invariably light;
while all specimens of i?. Kirhi/i are dark colored, and those of E. tvalcrsiamis
intermediate between the two.

Bhodocrinus parvus s. A. Millkr.

1891. S. A. MiLLEiii Gool. Kcp. Missouri, Bull. 4, p. 39, Plate 5, Figs. 8, 9.

Closely allied to i?. nanus, but a somewhat smaller species and the calyx
more depressed. Calyx subglobose, wider than high ; the plates moderately
convex, and covered in exceptionally well marked specimens by ob.scure
ridges* passing from plate to plate; suture lines distinct. Infraba.sals slightly
extending beyond the column. Basals the largest plates of the calyx, bend-
ing gradually upward. Radials nearly as large as the basals. The two
costals together smaller than the radials, and frequently anchylosed. Dis-
tichals five, very small, only the first a calyx plate, the succeeding ones free ;
the upper axillary, and supporting two arms, which do not branch again.
Arm openings arranged in pairs, each pair separated by a wide interspace.
Arms delicate, composed of two series of deeply interlocking, cuneate pieces,
the intervening sutures grooved. Pinnules not in contact laterally. The
plates interposed between the radials very large, especially that of the anal
side Interbrachials 2, 3, and 2, apparently also at the anal side. The
ventral disk not exposed in the specimens.

Horizon and Locality. — Lower part of Warsaw limestone; Booneville, Mo.

TyiKs in the collection of Mr. S. A. Miller.

• We nre leil to Relieve tlint tlic ridfjes in Jliller's (iffurcs are too distinct and inislcadinf;. In fivi' speci-
mens in the Missouri State collection with Jliller's label attached, there are no ridc;es at all, and I he surl'iiee
is smooth or slightly roughened. That this is not owing to the preservation is sliowu by the I'lict thai llie
other parts are sharply defined.

230

THE CllINOlDEA CAMERATA OF NORTH AMERICA.

RhodoorinuB Barrisi Hall.
Plate XII. Fiffs. 3, 4a, b, c, d ; and 5a, h.

1861. Hali; Prelim. Notice of New Spec, of Criii. (Allmiiv), p. 9.
ISOl. lUu,; Boston imm. Nat. Hist., Vol. YII. (No. 2),' p. 'Hi.
1872. Hall; N. Y. SIntc Miis. Nut. Hist., Bull. 1, Plate C, Figs. 16, 17.
1S81. W. ami Sp.; Kevisioii Pulieoer., Part II., p. 212.

Sjii. Rlwilocrhiiiii Barrisi, var. ditergeiis Hall, 1801; Boston Jouru. Nat. Ilist., Vol. VII., p.
321; ami N. Y. State Mus., Bull. 1, Plate 6, Tig. 18.

A very variable species, of the style of Gilbertsocrimts. Calyx forming
a polyhedron, with slightly impressed faces and a node at each angle. Dorsal
cup broadly truncate at the bottom, widest at the middle of the radials,
whence it tapers rapidly and uniformly to the margins of the tegmen, whose
diameter is from one third to one half smaller than that of the widest part
of the dorsal cup, and less than the diameter at the truncated lower part.
Plates highly elevated, their middle portions crowned with spine-like pro-
cesses or elongate nodes, connected by well marked ridges, which traverse
the sutures and meet with the nodes of adjoining plates. The nodes upon
the basals are longer, attaining in very mature specimens a length of four to
five mm. by two mm. wide ; they are directed oblifjuely downward, while those
from the radials, costals, and interradials point horizontally. In less mature
specimens, as a rule, the nodes are comparatively smaller. The ridges
connecting the basals form around the bottom of the calyx a well defined
pentagon, with a shallow concavity occupying the whole width of the lower
face, enclosing the infrabasals and fully one third of the basiils.

Infrabasals small, but their upper angles visible beyond the column.
Basals proportionally large ; their upper half abruptly bent upwards so ns
to take part in the lateral walls, and forming a sharp edge on which the
caly.x rests. Radials a little smaller than the basals. Costals very small ;
the first less than one third the size of the radials, but twice as large as the
second. Distichals eight to twelve ; the plates of the first row, and some-
times those of the second, incorporated into the calyx and in contact later-
ally. The free distich.als short, cuneate, and in large specimens interlocking ;
the upper one axillary, supporting two arms, of which either one or both are
branching once again. Arm openings elongate ; arranged in pairs ; directed
horizontally. Arms about twice as long as the height of the calyx ; cylin-
drical ; somewhat divergent ; the plates sharply cuneate and interlocking.

I 'i

RIIODOCRIMDiE.

231

Pinnules contiguous ; their joints as long as two of the arm plates. First
interradial followed by two rows of iuterbrachials of two each, except at the
anal side, which has from three to four plates in the second row ; the first
almost as large as the radials ; the succeeding ones very much smaller. Yen.
tral disk slightly elevated, flnttened in the middle ; composed of fourteen to
sixteen rather large convex or conical plates, indefinitely arranged. Anus
marginal, directed obliquely upwards. Column short, gradually tapering ;
joints moderately high, the edges almost straight.

Horizon and LomVdij. — Upper Burlington limestone ; Burlington, Iowa.

Types in the Museum of Comparative Zoology, Cambridge.

Bemarlis. — The specimen described by Hall as variety dkcrrjms is a very
mature form of this species. In the smaller specimens the branches of the
arms are less divergent.

Rhodoorinus Barrisi var. striatus W. & Sp.

Plate XIL Fifj. 6.

Calyx almost cylindrical, broadly truncated at the bottom, but not exca-
vated. Plates moderately convex, without nodes. Surface covered witli
well defined ridges, which meet with similar ridges from adjacent plates.
The ridges connecting the basals and those proceeding from the radials to
the adjoining basals forming a triangle, which encloses another whose ridges
are somewhat less distinct. The form and arrangement of the plates simi-
lar to those of the typical form, but the ventral disk proportionally larger,
and composed of a greater number of pieces.

Horizon and LocaUti/. — Upper Burlington limestone ; Burlington, Iowa.

Type in the collection of Wachsmuth and Springer.

Rhodoorinus truncatus w. & Sp. (nov. spec).

Piute XIII . Fiffs. 2a, b, c, d, c, /.

A rather small species. Calyx wider than high, pentangular in outline,
broadly truncated at both one's ; the sides nearly parallel, a little wider at
the arm bases. The truncation of the lower end not only extends to the
greater part of the basals, but includes small portions of the radials. The
base is pentangular in outline, not excavated, except the middle part very
slightly for the reception of the column. Plates convex, a little tumid, with

fi'^

232

THE CRINOIDKA CAMERATA OF NORTH AMERICA.

obscure ridges or angularities passing out from their margins, and meeting
tliose of adjoining plates ; the median portions perfectly smooth.

Basals and radials of nearly the same size, both bending abruptly upward,
the former to three fourths their length, the others only at the lower ends.
Costals one or two ; togetlier about one half the size of the radials, very
frequently anehylosed, there being scarcely a specimen with two costals in
all five rays. Of the distichals generally but one plate takes part in the
calyx — in very large specimens sometimes two — which is as large as the
second costals. Arm openings two to tha ray, facing sideways. Arms un-
known. Interradial spaces fiattened, composed of 1, 2, 3 plates, followed by
two others between the arm openings ; the plate between the radials not
larger than the interbrachials above ; the two latter separated by a shallow
depression, which gives to the arm bases a somewhat lobed appearance, and
to the tegmen a pentangular outline. Anal side wider, with three plates in
the second row ; the plates of the median row forming a vertical ridge of five
pieces, which passes up into the tegmen. Ventral disk comparatively large,
almost flat; composed of about twenty slightly convex plates, of which
those near the margin are the largest. Anus marginal, on top of a small
protuberance.

Ilorizon and Localltif. — Upper Burlington limestone ; Burlington, Iowa.

Types in the collection of W.achsmuth and Springer.

Remarks. — This species resembles the two preceding, but differs essen-
tially in the form and proportions of the calyx. In those species the calj'x
attains its greatest width in the lower half of the dorsal cup, and the teg-
men is proportionally narrow ; while in this species the calyx is widest at the
bases of the arms. Besides it differs in the construction of the anal side, and
in having larger costals and distichals.

Bhodocrinus tuberculatus w. & Sr. (uov. spec).

Plate XIII. Figs. 3, 4.

A very knobby species ; somcvhat larger than the preceding one.
Calyx a little liigher than wide ; deeply excavated at the bottom ; decid-
edly bulging at the costals, whence it contracts uniformly to the margin of
the ventral disk, where the diameter is fully one third smaller — less than the
width at the lower end of the dorsal cup. All plates of the calyx, basals
and infrabasals excepted, extended into conspicuous angular tubercles, of
which those upon the radials are longest and stoutest.

RIIODOCRINIDTI-:.

28a

Infrabasals placed >t the bottom of a concavity ; forming n penta-
gon, of wliich small portions are exposed beyond the colunni. Basals
smaller than the radials and without nodes or tubercles ; they rest within
the lower concavity, except their extreme upper ends, wliich bend slightly
upwards. Radials large, forming a rim upon which the calyx rests; their
tubercles quite long, rounded at the ends, and directed obliquely downward.
Costals comparatively large, their tubercles connected with one another, and
sometimes with those of adjoining radials and interradials by obscure ridges.
Distichals one in the calyx, provided with a horse-shoe-shaped facet lor the
reception of the free brachials. Arm openings elongate, facing laterally ;
structure of the arms unknown. First interradial followed by interbrachials
in succession of 2, 2, and two more between the arm openings. The anal
interradius has three plates in the second and succeeding rows, but the plates
are not formed into a ridge or placed in a straight line, their arrangement
being rather irregular. Interdistichals one, on a level with the arm openings.
Togmen very small, flat, and of the plates only the ends of the tubercles vis-
ible from a side view ; the plates large and irregularly arranged. Anal open-
ing marginal.

Jlorhon and Locnlity. — Age of the Lower Burlington limestone, Lake
Valley, New Mexico.

Ti/2)es in the collection of Wachsmuth and S])ringer.

Bcmarl-ii. — This species, which has the general habitus of certain forms
of Gi/krtxocriiws, differs from all other speci''s of Bhodorrnnis in the form of
its nodes, which cover almost the whole face of the jdates. The largest
nodes occur on the radials, and not on the basals, those of the latter plates
being often wanting altogether. It also differs in the form and greater size
of the costals and distichals.

; r

GILBERTSOCRINUS Phillips.

1830. Pilll.Lirs; Gpolofry of Yorksliire, Part II., p. 20?.

1811. MuLLKii; Berlin. Acnd. ilcr. Wissenscli., p. 209.

18W. U'OiiiiiONv; Piralrumc I., p. 155.

1852. U'Oiiiur.NV ; Cours olemeiit.. Vol. II., p. 142.

1905. Meek nnd AVoktukn ; Proceed. Acad. Nat. Sci. Pldln., p. 166.

1872. H.U.I.; N. Y. Slate Mils, of Nat. llisl.. Bull I., Plate hi and Plate VI.

1S73. Meek and Woutiien; Geol. Uep. Illinois, V(d. V., p. 3S9.

1875. Grenfei.i, ; Proceed, of Bristol Naturalists' Soc, Vol. I., Part III., p. 483.

Syn. O/ZmT/BOT CiMiiKUi,.\Nn ; 1820, Appendix to Reliqnin? Conservain!, Plate D ; 1877, Waclisnmlli;
Anier. Jonru. Sci., Vol. XIV., p. 125 ; 1S7S, Zittel ; llandh. d. Palaeont., Vol. I., p. 376 ; 1^81,
W. ami Sp. ; Uevislon Palifoer., Part II., p. 213; and Proceed. Aead. Nat. Sei. I'liila., p 387;

.30

234

, i-'i

THE CRINOIDEA CAMERATA OF NOUTH AMERICA.

1885, \V. BiidSp. ; llcvision Pulicocr., I'lirt 111., p. 99 ; niul Proceed. Acad. Nut. Sci. Philii

p. 321.
Syii. Rhodocriiius Ue Kon. mid Lk Hon, 1853, Kcclicr. t'riii. Curb. Uelg., ji. lUt; llnciner, 185.).

LetliiRU Ocogiioht., p. 240 ; I'ictot, 1857, Tniite dc I'aleont., Vol. IV., p. 311 ; E. Hillings, 185S,

Canada Surv., Decade III., ])p. 25 k •ifi; Dujardiu and llnpe, 1802, Hist, natur. des Zooplivtn

Erliiuod., p. 123; Kofc, 1865, (Jeol. Magazine, No. 12, p. 217.
Syn. Oonittsleroitloeriiiua LvoN and C.iS.sKinY, 1S59, Amer. .lourn, Sci., Vol. XXVIII., Scr. 2, p. 233;

Meek and Worllicn, 1809, Proceed. Acad. Nat, Sci. I'liilu., p. 73 ; S. A. Miller, 1877, Calal.

Palffioz. Foss., p. 80, mid 1889, N. Am. (ieol. and I'aliconl., p. 219.
Syn. Tremntorriniis Hai.1., 1800, Siippl. Geol. Itrp. Iowa, Vol. 1., p. 70, and Prelim. Notice of New

Spec. ofCrin., p. 9; Meek and Wort lien, 1800, Proceed. Acad. Nat. Sci. Pliila., p. 3SH ; Hall,

1861, Jonrn. Host. Soo. Nat. Hist., Vol, VII., p, 325, and 1802, 24tli Hep. N, Y. Stale Cab.

Nat. Hist,, p. 128; Meek and Wortheii, 1806, Geol. Kep. Illinois, Vol. II., p. 217.

.7/?A.,

Fig. 11. — Gilberhoerinu!.

lb = infrabasals, b = basals, R = radials, I = costals, II = distielials, TIT = palmars, A = arms, AO = ami
openings, ir = interrndials, ibr = iiilcrbrachials, IUA = iiitcrradial appendages.

Dorsal cup greatly exceeding the disk in size ; the former elongate, more
or less cylindrical ; the latter flat or low-hemispherical, its margin extended
into ten tubular appendages, passing outward and downward. Plates smooth
or radiated, nodose or spiniferous.

RHODOCRINIDVE.

286

Infrabasftls five, small, pentagonal ; forming a flat, impressed pentagon
at the bottom of a concavity. Basals large, heptngonal, widely truncate
above. Radiuls angular at the bottom. Costals two. Distichals 2 X 10 in
the calyx ; the upper ones excavated to form the lower niargin.s of the arm
openings, of which there are two to the ray, one to each main division. The
arms are in clusters, delicate, branching and biserial from the last axillary ;
they either stand erect cand fold over the disk, or are pendent, their ventral
furrows exposed to view. Pinnules rather strong and closely packed to-
gether. Interradial areas large, composed of numeious plates; those alter-
nating with the radials considerably larger and frequently nodose, the
inter!, ihials arranged in vertical rows. Anal intcrradius generally not
distinct in the cup.

Ventral disk nearly flat, with five pit-like int( dial depressions, of which
the posterior one is considerably the largest ; the bottom of the pits formed
by small polygonal pieces, surrounded by larger plates. In the European
species, in which the pits are less conspicuous or even wanting, the disk
plates differ but little in size. The outer margins of the disk are extended
outward, and form ten large tubular appendages, which are pendent, in some
species reaching down below the calyx. These appendages are formed either
by a single row of cylindrical joints, or by throe rows of plates longitudinally
arranged, two of them ventrally disposed, the third dorsally ; but when two
of them are suturally connected, the consolidated part is composed of two
and six plates respectively, iae tubes are all pierced to their full length
by a central canal, which, on entering the calyx, connects with the sub-
tegminal grooves at the inner floor of the disk. In the European species,
the ten appendages are free from their origin in the calyx, and those facinr^
the same intcrradius are separated from each other by interradial platr^. In
the American forms, however, with the exception of G. s/iiiiiffcnt^ from the
Hamilton, and G. Jiscvlhis from the lower Burlington, the tubes meet in piiirs
at midway between two rays, and are for some distance laterally connected
by a rigid suture ; but, although apparently forming a single a])pendage,
each one from the base up has its own canal, and the two canals of the same
set connect with different ambulacra. The arm or ambulacral openings are
located beneath the appendages; they occupy the bottom of a small, funnel-
shiiped pit, and are formed betw.een the .second distichals and the proximal
])lates of the appendages. Anus subcentral. opening out directly through
the togmen, and occupying the upper (inner) end of the posterior depression.

236

TIIK CHINOIDKA CAMP:RATA OF NORTH AMERICA.

Ornls of latlu'r ini'giilar arraiigcinent, and their iduiitification NOtnetiineH
ilifficult in certain wpccio''.

Column circular; the nodal joints considerably wider and higher, rounded
, at their edges; axial canal pentalobate or stellate, the angles directed
radially.

Distribution. — Gilbcrtmcrlnm occurs in America and Europe. It first ap-
peared in the Hamilton group, reached its climax in tlic two Burlington
beds, and became extinct before the close of the Keokuk epoch.

licniurks . — The name OUdcrimis, the earliest name given to this form,
was proposed by Cumberland in 18'20, in an appendix to the Reli<|ui£B Con-
servatiu. lie published no generic diagnosis or specific name, but gave an
excellent figin-e, by which the type is easily identified. Of the plate con-
taining this figure, however, we have been informed by the late Dr. P. H.
Carpenter that only a few copies were distributed in a private way, and that
no copy of it is to be found in the Library of mc British Museum.* For this
reason it cannot be looked upon as lawfully published, and the name will
have to be given up.

Phillips proposed the genus Gilbert sociinm in 1836. He included in it
Ciunberland's type, which he described as G. cakaratiis (PI. XV. fig. 5). His
figures are fairly good, but the descriptions are meagre, and show no essen-
tial departures from Ithodocrinus. Neither does he make any allusion to the
two diflerent sets of openings, which are so well represented in his figures.
The arms are described as " rounded and perforated in the centre."

De Koninck and Le Hon, in 1854, declared that OUacriiius and Gilbert-
Kocriiim were synonyms of lifiodocriniin. They probably arrived at this con-
clusion from their " Rhodoerimis n/elldm" which we find to be a true Gilbert-
socrinus (PI. XV., fig. 4). Similar views were expressed by Roemer, Pictet,
and Dujardin and Ilupe.

In 1859, Lyon and Casseday described a new species from the Carbon-
iferous of Kentucky, and made it the type of a new genus : Goniasteroido-
crimis. The species closely resembles that figured by Cumberland and
Phillips, except that the supposed arms (appendages) are suturally connected
by their sides, in pairs, for some distance ; while those of the Briti.sh species
are separate from their origin. Lyon and Casseday's specimen was in excel-
lent preservation, the so-called arms being .all in position, and it had below
and between these " arms, in the interradial fields," as they state, clusters of

• We saw it iu the Cambridge copy wliicb was formerly in Do Koiiinck's library.

■..ii

RIIODOCUlMn.K

237

from five to seven "long pemluluuH cilia" bearing Jolicate pinnules. The
pinnuliited " cilia" tliey aftoivvards refer with ii query to urinM.

Hall in 1860, without nmking any conipaiison willi Giiuiustei-ouhcrinm,
described under the new name IVemutwrinus, a number of specieH from the
Subcarboniferous, of undonbteil generic identity with Lyon's specieH. lie
also regarded the upper api)endiiges as arms, but doubted if tin.'y could have
performed the functions of arms. lie further suggested that probably the
•' foramina" above t'.ie secondary radials served for the protrusion of '• lleshy
arms or tentacles." However, a year or two later he described his Tixmuiu-
crinus Hpiniyeriix with '• summit arms" and '• true arms."

In I8G0, Rofe, who apparently was not acquainted with the writings
of Lyon and Hall, while discussing certain morphological questions, assorted
that Phillip-!' species of GilhcytaocrmiiH " are undoubtedly lllmhcr'nn." He
also stated that lihoducruwa differs from most of the other Crinoids " in the
form of the arms and in the position of the ovarian apertures." and that
"the arms have no grooves on the upper side, but are cylindrical, with a
tubular canal through thj a.\is, and the ovarian openings placed immediately
under the ba.so of the arms." In reply to Billings' supposition that the
upper appendages might possibly be spines, he said : " their articulated struc-
ture, and the passage through the a.\is forbid the idea of their being
spines."

Meek and Worthen, in I860,* discriminated between Gil/icrtsocriiuis and
Gomaatcroidocrinus ; making the latter a section of the former. Gilkrisorri-
mis was said by them to have the " p,seudo-ambulacral appendages " located
directly over the interdistichal spaces, and Goiiiat^toyndocriniis over the inter-
radial ones; and they sta "d that these structures are not rrms, that they
" differ essentially from all appendages of the body in any known Crinoid,
and .seem to bear somewhat the same relations lO the body, that the side
branches of the column o( Pciitacriniis and many Palaeozoic Crinoids do to the
column itself." The " true arms," they say, connect with the calyx at
the lower openings, which Hall described as foramina in IWiiiatocriiius.
They gave a description and good figures both of the true arms and the
appendages.

Grenfcll, in 1875, defined GiUiertsocriinis as follows : " Bnsals five ; sub-
radials five ; radials three ; brachials several, generally irregular ; the
second brachial channelled at top, and leading into an orifice which com-

Geol. Rep. Illinois, Vol. II., pp. 219-221.

288

TIIK CUINOIDEA CAMEUATA OF NOUTH AMERICA.

mimicntes witli t!io porforiition in the uriiiH; axillary plates well developed ;
arms round and 'oiierally set iit right angles to the body." Ho took the
upper openings, / c, the central perforation following the median line of the
appendages, to be "elTerent tubes, " carryiin' off the water ii>ed for respira-
tion, which he thinks in oth':r grcps is performed by the anal tube.

From numerous specime ^ '» ur collection, some of them with all of the
two kinds of rppendages ^ ed to their full length, we are enabled
to fully confirm ilie opini "i" ' .-ek and Worthen that the smaller, pinnule-
bearing appendages are r n- id that the stouter, tubular ones are struct-
ures unlike those of other Ci'ii' ids. What ♦he functions of these tubes may
have been can only be co. j tured, but they were jjroltably not identical
with tiiose of the cirri, as Meek and Worthen supposed ; and we are inclined
to think, from the fact that their canals conmninicate with the subtegminal
galleries at the inner floor of the ventral disk, that the functions, as sug-
gested by Grenfell, were respiratory, anil that the canals performed a similar
ollice to that of the respiratory pores of Jiafucrimia and the spiracles of the
Blastoids.

Meek and Worthen, in separating the Europoon species from the Ameri-
can, were i)robal)ly not aware that the coalesced appendages are actually
pairs of distinct tubes, each one having a canal of its own, and the canals
of the same pair communicating with diiTerent ambulacra, in a way similar
to that of the paired spiracles in the Blastoid genus Pcutraidtcs. It is in this
respect exceedingly interesting that in (rilbcr/socn'nm /lirtl/iis the posterior
appendages are simple, and are widely separated by a row of anal plates,
exactly as in the Emopoan species ; while those of the four other sides are
iniited at the base. The species thus represents at two of its sides the
Einopean form of the genus, and at the other three the American.

Another interesting fact in the developmental history of the genus is
that in the species of the Burlington limestone the consolidated tubes are
composed of the single cylindrical plates of two simi)le tubes united laterally
by suture. In the transition beds between the Burlington and Keokuk
groups appears the rare species G. oborti/iis, in which the two rows of plates
composing the double tubes of its predecessors are roofed over by four more ;
and this character becomes constant in the Keokuk, where the genus is
found quite abundant in .some localities.

The genus lihoJocrbiiia. which has been so frequently confounded with
Gilbertsocriinia, has arm openings only, the tubular appendages being un-
represented ; otherwise the two genera cannot be distingui.shed.

■

KIIODOCIMNID.K.

23!J

•

Oilbertsoorlnua tuberosua (Lvov mid Casm.).
Plate XV. Fl<js. Ja, >> ; I'littc XVI. Flyx 1 to C ; J'lule XVII. Fhj. G.

1800. Ouniunli'iniduirinU' liilirra-iii^ — LvoN iiiiil Cammk.dw; Aincr. Joiini. Sci.,

2:t:i.
1866, OlHierlmcriiiHn (OuHiiisleroiducr.) luUrumix — Mkkk niul Worth KN ; (linl

2:20, will) (|{ii(tmiii.s,
1831. Otliirriiiim liiln-rmim—W . niid Sr. ■, Ucvisioii riilii'iin-,, I'l. \\., , 219.
18S0, Ooiiiinlrroidiii-riiiim lu/n'ruiim — H. A. Mir.l.Klij N. A. (i((il. and I'lilii'oiil.,
Slice(« I7tli Ut: flcdl, Siirv. Iiidiiuj;!, . ,-il, I'liitc ',), V'li:. 11.
Sjin. TremiilocriiiHi rultmtus IIai.i,; IsOO, Sul. (Icol. I(c. Imva, . 77.

Vol. X\ VI II., (Scr, 2),
He, liliiiuis, V(il II.. .

. «0; mid l^ni, Adv.

Calyx large, a little liiglier tlian wide. Dor.siil cup siibcylindncal,
slightly constricted at the nrin regions, it.s lm-<e dooplv excavated. Ventral
di,sk flat, with deep interradial depressions; the appendages pendent, long,
and frequently branching. Plates tumid, the radials drawn out into elon-
gate nodes or obtu,so npines, directed downward.

Infrabasals sniall, almost completely covered by the colnmn ; forming
the bottom part of the concavity, of which the basals constitute the sides,
and the radial."? with large interradial plates between them form the rim
of an inverted cono on which the remainder of the calyv rests. IJadials
longer than wide, considerably larger than the eostals. 'I'he interradial
plates large and covered with a sharp node. Costals hexagonal and hepta-
gonal. Distichals two in the calyx, smaller than the costals, and abont as
wide as long. Arm openings of the same ray widely apart, separated by
two or three intcrdistichals. Arms pendent, slender, branching, and with
long pinnules; there being six nltimate arms to each arm opening. Caly-
clne appendages in ten pairs, di,sposed interradially ; those of adjoining rays
in sutnral contact to about 12 mm. from the calyx, when the pairs separate,
and the two tubes take a sharp outward turn, so that their tips meet with
those of adjacent pairs. Each tube is composed of three rows of plates
longitudinally arranged, two of them occupying the ventral, the third the
dorsal side, so that there are six rows for the distance to which they are
united. The tubes generally branch once or twice; they are long, and
taper gradually to their tips. Interbrachials arranged longitudinally in
three series of plates of nearly equal size ; the anal side not distinct. Vent-
ral disk low-hemispherical, almost flat, the plates highly convex, tho,se form-
ing the interradial depressions .somewhat smaller. Orals a little larger than
the other di.«<k plates, and rather irregular in their arrangement. Anus

(1-^

240

TIIK C'UINOIDKA CAMKUATA OK NOUTll AMKKICA.

rtliglitly I'xcuntrip, forming ft niiDple opening through thu tcgnien, and in
nioxt of tiio Hpi'i'iuions covered by a 2'iii/ytrrits njitihihru Hall. Culunin
rounil and nitlior ntotit.

Ifiirizon mill LuntHlii — Keokuk group; C'rawfoidsvilK', Ind. ; Hardin
Co., Ky. ; and Kookuk, Iowa.

7///>t' in the Lyon rolleelion.

/tiiiiiirh. — Tiii.s Hpeeie.H \x Lyon and C'a.'^seduy'H type of the genuM (/oiii-
iinUroidocriiiiix,

OilbertsoorinuB dispansus w. mid Sr. (nov. sp.).

I'/>itr X r. Fl</.s. J,i, f>, r, d.

Sjn. doiiiim/ei-riihrriiiiiK /yiNiiiuHi — 8. A. Mil,Lt:H i Oi'iil. Surv. Illiiiiiis, Hull. 3, p. 55, rintp 4, Kip. ►.

Of the typo of (,'i/f>irf>imr!iiits htherosiw, hut a sninllor Hpecies, the nrnm less
iiumorons, mid the oalycine appendages proportionally larger. Calyx noine-
wlmt deprcHsed, wider than high, truncated nt the bottom, the median
portions deeply excavated. PlateH convex except the radials, which are
extended into elongate nodes or obtuse spines directed oblirpiely downward.

Infral)asals small, placed at the bottom of the concavity, and almost
covered by the column. Ihisals rather small for the genus; their distal ends
cur>ing upwards and forming together with the median portions of the
radials a rim upon which the calyx rests, while the lower portions of those
l)Iati'.s are involved in the concavity. Radials very large, more than twice
as largo as the costal.s. Cosfals and distichals of nearly the same ."i/e.
slightly projecting over the plates of the interradial and interdistichid areas.
Interradiul areas composed of 1, 3, 3, 2, 2 plates; the middle one of the
second and thinl rows a little larger, and raised somewhat above the level
of the two outer ones; the anal side not distinct. Interdistichals three,
longitudinally arranged. Tegmen flat, with five deep interradial depres-
sions, of which the posterior one is twice as large as the others ; all of them
oval in outliiu', and surrounded by a series of nodose pieces. The anal open-
ing occupies the inner end of the larger depression, and in perfect specimens
appears to be closed by a pyramid of numerous very nunnte pieces. The
smaller depressions are paved by fom' or five larger plates of irregular form.
The appendages are given off in pairs from the calyx, being for (|uite
a distance laterally connected ; they are very large, slightly pendent, and
each pair is composed of six longitudinal rows of transverse, slightly nodose

mioDocuiMn.E.

941

piocci, nltorniituly arrangud. Tliey Mf[mrate iit tlio ciglilh ur toiitli pluto,
wlieii tlioy buiul abruptly outward in opixisito diructious, aud earli Minipio
tubo in tliuncu competed ol' tbrtiu niwH <jf piucos. Arum wliort, puiiduiit, and
recumbent; tliey aro coinpo«ed of two rowM of platuM, and |)innuIatL'd.
Thoru being hIx ariun to each arm oi)ening. three to each main division,
but rarely more tiian three aro exposed to view, the otherM being eoviMed by
the appundagefl.

Jlorixon ami Lomiiti/. — Keoicuk group; Indian Creok, Moutgoniory Co.,
Ind., where it has been found in splendid preservation.

Ti/pea in the collection of Wachsiuuth and Si)riuger.

Oilbertsoorinus obovatus ^W.r.K and Woutmk.v.
P/ute X VII. J'^fjs. 4,t. b.

ISflO. Oonin.ffi'roiilorriiiiis nf/or/i/'i.'i—Mr.r... (viul Woutiikn ; I'mcreit. Aciul. Nul. Sci. I'liiln., p. 7fl j nml

1H7;|, (Icnl, ll,'|). llliniHs, Vol. V, p. W\. ridtl' 4, Fi,lt 0.

19S1. OUaeriimt ohuealm — \V. nnJ Sp. ; I.. 'iKiiiii l'Mln'ocr., I'l. II., p. rfl'J.

Calyx nrn-shapod; basal concavity deep, bit narrower than in any of the
other specicH ; the sides of the donsal cup convex, con.stricted at tiie arm
bases; greatest width across the second C'-ntals; voi .ul disk perfectly flat.
Plates without ornamentation, strongly convex, and . i' ather uniform si/e.

Infrabasals small, forming together with the lower part of the basals
an inverted cup. IJa.sals larger than aii) »ii'i r plates of the . lyx, bending
abruptly upwards and exposing two tlii ds c ' their surfaces in a A\\\i view.
Radials a little longer than wide, slightly larger than the costals, the ; vi (•
faces distinctly angular; the interradial jdates considerably smaller. i)is-
tichals two, larger than the adjoining intt rbrachials ; the second smaller
than the first. Arm openings proportionally small, at the bottom of a
shallow pit. Calycino appendages continent at the proximal end, and
interradially disjiosed. Each pair, before separation takes place, is composed
of six rows of plates, and each tubo pierced by a moderately large central
canal. Length of appendages unknown, as is also the form and construction
of the arms. Interradial areas elliptical, arched by the distichals and the
plates supporting the ap,, u'^^ges ; they aro composed of about thirteen
plates; arranged: 1, 3, 3, J ., or I, 3, 3, 2, 2, with slight variations at the
anal side. Interdistichals six to eight, the first touching the axillary distichal.
Plates of the ventral di-k rather large and strongly convex; the interradial
depressions small, ei-bracing only one or two pieces. Orals not distinct from

242

TIIlv CKIXOIUEA CAMKRATA OF NOKTII AMKUICA.

'II

ill,'

'ill

the other plates. Anal opening alinost central. Column rounil, filling
nearly the whole width of the basal concavity ; axial canal small and pent-
angular.

Ilurizon and LocuUlij. — Highest part of the Upper Burlington limestone,
Burlington and Pleasant Grove, Iowa. Rare.

TijiK in the Museum of Comparative Zoology, Cambridge.

llonnrhs. — In this and the two preceding species, which were the last sur-
vivors of the genus, the individual tubes arc constructed of three rowt.
of plates instead of a single one as in all others. This species, however,
differs essentially from all others in the form of the calyx. While in G.
tiihei'osiis and similar forms the ba.«als form the sides of the lower concavity,
they are placed in G. obomtm at the sides of the dorsal cup, which is
decidedly convex in the latter, but flat or even concave in the former.

Oilbertsoorinus typus (\\\\-\.).
Plate XIV. Fiys. I, 2, 3, and Flute XVII. Figs. 7a, b.

1859. Tremaloeri/ma fypiit — Hau-; Siip|)l. Geol. Ucp. Imvn, p. 73.

il872. Giliir/ioiriiiHn {Tiri,ialocriiiii.i) h/iiim— IIai.i,; Hull. Museum Nat. Hist., Tlatc 0, Fi'd- 13.
1S?3. 0'iiiiiinliT(iiitiirriiiii.i li/pus — Mkkk aud Woutiikn; (Icol. Hop. llliuoi.s, Vol. V., p. 391),
18S1. onucriiim /,i/iiu.i — W. and Sr, ; lievisioii I'alavior,, I't. II„ p, 219.
13S9. Guiiidsti'roiilucrliHis ti/pii* — S. A. Millkk ; Norlli Aiiicr, Geol. and I'iila'ont., p. 250.
Sjii. Trciiialofriiiini iiii)iil!ulu.i IIai.i, ; .Suppl. Ge(il, Hep, Iowa, A'ol. I, p. 7'i,

Calyx broadly concave at the base, somewhat inflated at the middle,
contracted near the top, spreading above into a projecting rim around the
upper margin. Ventral disk low-hemispherical or .^lightly convex. Basals,
radial.s, and interndials produced into sharp central .«pines or elongate
nodes; all other plates convex and .slightly tumi*^!.

Infrabasals comparatively large, forming a pentagon, of which the greater
part is exposed beyond the column. Basals very large, curving so that the
lower halves of the plates rest within the columnar concavity, the upper
forming a part of the lateral walls of the dorsal c\ip ; their spines directed
downward, while those of the other plates are directed outward. Radials
much larger than the costals : the interradials one half smaller, but larger
than the interbrachials. First distichal smaller than the second, the latter
higher and axillary, supporting two arms, which branch from the third
palmar, and again on one side from the third post-palmar, making a cluster
of arms to each opening. Arms pendent, long and delicate, uniscrial to the
last bifurcation, when the plates become cuneate and interlock. Pinnules

\f[

RIIODOCRIXID^E.

243

well proportioned. Tlie calycine appendngcs pendent, unusually stout and
lonjf, and composed of cylindrical joints whose apposed i'accs are striated.
The joints grow longer as they decrease in width, and at the end of the
tubes are twice as long as wide ; they are thicker in the middle than at the
ends, and the median part is marivcd by a transverse row of little nodes.
The tubes of adjacent ambulacra are united to their sixth or seventh joints,
and the plates meet alternately by a zigzag suture. Interbrachials : 3, 3, 3,
3, 2 — exceptionally two in the first row — the upper row abutting against
the appendages. The anal side has an additional plate in the second row.
Interdisticlials about six to each area. Ventral disk pentangular in outline,
with five interradial depressions; the posterior one, which contains the anus,
larger; the plates of nearly uniform size and all convex. Orals uiuletermin-
able. Anus more excentric than in the preceding species. Column large
and round ; the nodal joints higher and wider, tlieir edges, like those of
the intervening joints, slightly rounded. Axial canal sharply stellate.

Horizon and Locality. — Upper IJurlington limestone, and Burlington and
Keokuk Transition bed; Burlington and Pleasant Grove, Iowa.

T^pc in the Worthen collection.

licmarls. — We regard Hall's Trcmalncrinus jm/nllatiis as a mere varia-
tion of this species ; the spines of the plates being shorter and the calyx more
robust. In the Revision, Part II., p. 210, we erroneously placed it as a
synonym under Gilbcrtsocrbms ttibcrciilusiis.

Oilbertsoorinus tuberculosus (Hall).
Plate XVI I. Fifjs. Su, b, c.

1859. Tremaiorriiiiis liibrrciilosiis — IIali. ; Siippl. Iowa Geol. Hop., Vol.. I., p. 7j.
1881. OUiieriiiiis lubcffiilosiin Vi. i.iid Sp. ; Uuvisiou I'alivncr., I'nrt II., )). 219.
1S89. Guiiin-i/i'ruiihrriiius liibprriilu.iiis — S. A. Millku ; Xciitli Aiiicr. I'alii'oiit., 250.

In the form of calyx and arrangement of plates, this species closely
resembles the preceding one, but the arms are erect inste.ad of pendent, the
appendages much shorter, and they taper rapidly to a point. Plates strongly
convex or slightly nodose, the surfaces smooth.

Infrabasals placed at the bottom of a shallow concavity, which is formed
by the lower half of the basals, the upper half curving upwards, and taking
part in the lateral walls of the calyx. Basals and radials considerably larger
than any of the succeeding plates. Costals fully one half smaller than the
radials. Distichals 4X10; the two lower, which are placed in the calyx, as large

''^ III

ft '

244

THE CRINOIUEA CAMKUATA OK NOKTII AMERICA.

as the costiils ; the two upper shorter and free. There are four arms to each
arm opening, the upper bifurcation taking place from the third plate. Arms
rather stout and long for the genus ; they are erect, biserial from the last
axillary, and have closely set pinnules. Calycine appendages small and short ;
directed outward, almost at right angles to the calyx. They are composed
of single joints, of which the four or five proximal ones of adjoining rays are
truncated laterally on apposed sides, and connected with one another by
rigid suture ; tlie plates interlocking. After separating, the two tubes taper
rapidly, and terminate at the end of the fourth or fifth joint. The nvnnbcr
and arrangement of the interradial plates is quite variable ; but in the major-
ity of specimens the plate between the radials is succeeded by three plates;
some, however, have but two, except at the anal side which always has
three ; there are two or three in the next row, exceptionally four at the anal
side. Interdistichals five to six. Ventral disk low-convex, with well defined
interradial pits; the posterior one larger, and containing the anus. Column
round ; axial canal sharply stellate.

Horizon and LocaUty. — Upper Burlington limestone ; Burlington, Iowa.

Ti/pc in the Museum of Comparative Zoology, Cambridge.

Remarlis. — Readily distinguished by the upright arms, and short, rapidly
tapering tubes.

Oilbertsocrinus reticulatus (Hall).

Flute XVII. Figs, la, b.

ISOO. TremotorriiiKii reddiliiliis — II.vLi, ; Dcscr. New Spec. Criu., p. 9: also Boston Journ. Xat. Hist.,

Vol. VII., p. 3ii5.
T8S1. Ollarriiius reiicii/u/u.i—W. i\ml Sp. ; Rcvisiou Palieocr., Part 11., p. 219.
ISS'J. Goiiiasteroidocrinus reticiihi'its — S. A. JIilleu; North Aiucr. Gcol. and Palicont., p. 250.

Calyx small compared with the preceding species, about as wide as liigh ;
dorsal cup urn-shaped with convex sides and a wide and deep concavity
at the bottom ; ventral disk almost flat. Plates slightly convex, their sur-
faces marked by a series of obscure ridges, radiating from the centre of the
plates to adjoining ones. The ridges follow the rays, and those passing
from the radials to the hasals are stronger antl somewhat higher ; the latter
producing around the basal concavity at the bottom of the calyx the well
defined figure of a pentagon with convex sides.

Infrabasals forming a pentangular disk, of which the angles project quite
plainly beyond the column. Basals largo, their upper ends curving abruptly
upwards, the lower portions of the plates to two thirds their length, together

RIIODOCRINIDiE.

245

With the infrabasals and the extreme ends of the radials, forming a wide and
deep inverted basin. Radials as large as the basals, a little longer than
wide. Costals nearly one half smaller than the radiuln, both of the same size,
and higher than wide. Distichals 2 X 2 in the calyx, nearly as large as the
ouitals ; the upper excavated to form the arm openings, whicli are largo and
circular. Appendages composed of single circular joints; the proximal ones
in contact laterally. Their length and the construction of the arms un-
known. Interradial spaces wide, elliptical ; the plates between the radials
smaller than the costals; the interbrachials arranged in rows of three and
two plates, which decrease but little in size upwards. Tiie anal interradius
apparently not distinct. Interdistichals one. Column round, composed
near the calyx of very short joints; the edges of the nodal ones knife-like.

Ilnrhnn and Locality. — Lower Burlington limestone; Burlington, Iowa,
and Sedalia, Mo.

TijiK in the Museum of Comparative Zoology, Cambridge.

Gilbertsocrinus flscellus (^Fekk ami Wohth.).

1S60.
1S()5.
1866.
18S1.
1839.

Plate XVII. Figs. 2a, b, c, d.

Tmiia(ofri«ii.f/fef/lit'i—yiEEK and Wnnxn. ; Proceed. Acad. Nnt. Sri. Thilii., p. 383.
Gilbert-wcrinii-i {Gmiiiisteroidocr^ fi!ir(>llus — Meek ami Worth. ; il)i(l., p. 167.
Gilljerhorriiiiis Jisn-llux — .Meek mid Worth. ; Gcol. Urp. Illinois, Vol. II., p. 2^2, Tlate 15, Fig. 5.
OUacrimisJhcrllm — W. and Si'. ; Revisir'i Palieocr., Part II., p. 219.
OonimteroiilocrinHsf.icellH.i — S. A. JIii.ler; North Anicr. Palicont., ji. 2.")0.

A small species, smaller even than G. rctkulatiif^, which it resembles
in general form ; but the sides of the calyx are straighter, the basal con-
cavity narrower, and the ridges upon the plates less con.-<picuous.

Infrabasals very small, covered by the column. Basals hidden almost
completely within the lower cavity, so that the radials and first intcrradials
form the lower ring of plates visible from a side view. Costals as long as
wide, and but little smaller than the radials. The second distichals support
the free arms, of which the first joint is short and quadrangular. The arm
openings of the same ray are placed closer together tlian in any other
American species, and the tubes bordering the anal interradius are simple,
with several interradial plates interposed between them; while those of
the other sides, on the contrary, are united in pairs. Nothing further is
known of the appendages and arms. Interradial areas arranged : 1, 3, 3, 3,
3, 2; the lower plate somewhat larger. The anal side gonerallv has five

• '

II I

246

THE CKINOIDEA CAMERATA OF NOUTII AMEHICA.

pliiU's in the tliiril, fourth, mid fifth rows, and two small plates above. Intor-
diriticiial areas composed of a rather large plate, succeeded by four or five
smaller ones. Ventral disk almost flat, with deep interradial depressions.
Some of the plates are larger and more convex, but none of them are refer-
aI)lo to orals. Anus subcentral, on top of a small protuberance. CoUnnn
unknown.

Jloriziiii ami Lorulif//. — Lower Burlington limestone ; Burlington, Iowa.

Tijjjc in the Museum of Comparative Zoology, Cambridge.

Gilbertsoorinus tenuiradiatus (^l. and w.).
Plate XVII. Fifj. 3.

ISCiO. Ooni.tsteroidocriiiiis IfniiintilUitus — Mir.K niul Woiitiib.v; Proccrd. Aond. Xnt. Sci. Pliiln., p. "J-
l>>(li. (loiiiiixlrniiilurriiiini Iciiiiiriidiatus — .\1ekk and WoiiTUEN ; Cn'ol .Kcp. Illinois, Vol. V., j). ShU, I'liilc

ll.l-iK.l.
1S81. Otlih-riiius l,;iiiii;iili,ilm — \\. mid Sr. ; Rrvision raliiwr., Part H., p. 219.
ISS'J. Ouiiiiisleroiilucrinus leiiiiirii</i(i/u.i — S. A. Millkb; Norlli Aiiier. Ge(jl. mid Palocont., p. 250.

The two specimens before us are considerably cru.xhed, and their general
form and the arrangement of the plates cannot be accurately determined.
It is a larger species than the two preceding ones, with which it is found
associated, and which it resembles in the delicacy of the plates ; but in other
respects it is more like G. (y/;/^s, of a higher horizon. The surface of the
plates is marked l>y a series of elevation.s, radiating from the middle of the
plates to adjoining ones, whi('% however, are not ornamented ridges, but are
produced by a folding of the plates. The basal concavity is quite shallow,
and composed almost exclusively of the infrabasals.

Basals large, curving upwards and inwards, their upper lateral faces
longer than the corresponding lower ones; they arc extended into a sharp,
slender spine rising from the centre of the plates, unlike the case of G. tiijius,
in whieii the .spines cover the whole surface of the plate. Radials very
large, and mounted with similar spines as the basals. Arms given olT from
the .second distichals ; their structure unknown. Calycine appendages very
long, and tapering but slightly ; their joints are strictly cylindrical and
devoid of ornamentation ; they are arranged interradiall}- in pairs, and tlio^e
of each pair are connected laterally by zigzag sutiu'cs to the fourth or fifth
joint, when they become free and diverge in opposite direction."?. The
number of arms and the number and arrangement of interradial and inter-
distichal plates cannot be ascertained in tlio specimens.

RIIODOCHIMD.K.

247

ir<>rlzon and Larnli/i/. — Lower Burlington limestone; Burlington, lowix.

7'ijpe in the Museum of Comi)iirative Zoology, Cambridge.

lionarks. — This species is distinguished from G. Ii/pnn by the form of
the spines on the bnsals and radials, the thinness and delicacy as well as the
folding of the plates, and by the cylindrical form and smoothness of their
appendages.

Oilbertsoorinus spinigerus (,iiali.).

Plate X V. Flijs. o'a, h, c.

1Sfi2. Trnmlorriintf .yi!ii!fffnis~U\u.; l.jth Kcp. N. Y. State Cal). Xat, Tlisl., p. 128.

ISfifl, Giwiaaternidocriiiiin uphiii/rriis — Mkkk niiil WoiiTil.; (icol. Surv. llliiKiis, Vol. II., p. 222.

ISri. Gilbfrlmriiim (TrcmiilijcriiiK^) yiiiiii/i'ni.i — Hall; New Voik Stale Mus. Kut. liibt., Bull. I., Tlate

Irt, Fiu. 9 (privately (listribiitcd).

1S77. Goiiiaalfrniilm-riiius.iiiiiiiiirru<, — S. A. JIn.LERj Cat. .Xiiior. I'aln'oz. Foss., p. SO.

I'-Sl. OlliicriiiM xfiiinijfrm — W. and Si'. ; KivUiou I'alicocr., I'arl II., p. 219.

1SS9. GoniiisleroiJoeriinis spiniyeiun — S. A. MiLLEB; North Aiiicr. (Icol. and Pala'niit., p. 2.')0.

A small species. Calyx widest acro.ss the radials, somewhat constricted
at the arm bases, expanding at the upper nuirgin. The rays marked by
broad, rounded ridges proceeding to the arm openings, and giving to the
section acro.ss the co.stals a pentangular, and across the distichals a deeagoiuil
outline ; while the .section at the margin of the disk, where the appendages
meet in ptiirs, a.sstimes again a pentangular outline, but the angles ai-e inter-
radial instead of radial. Tl>e plates without ornamentation, but the radials,
first costals and first interradials are extended into sharp nodes or small
.spines. Basal concavity deep and wide, involving the infrabasals, ba.sals, and
portions of the radials and interradials.

Infnil)asals comparatively large, forming a regidar pentagon. Basals
large their upper sloping faces twice as long as the corresponding lower
ones ; broadly truncate above. Radials of nearly the same size as the basals,
and deeply wedged in between them. First costals considerably larger than
the second, and but little smaller than the radials. Distichals quite small,
especially the second, which is deeply excavated to form the arm openings.
Cidycine tubes confluent at four sides, those facing the anal side simple and
separated by anal plates. The appendages are short, directed almost horizon-
tally, and are composed of joints about as long as wide. Anns erect, rather
stout, the plates cuneate ; they start in pairs from the calyx, branch on the
fifth plate, and again on the eighth. The plates of the interraditd spaces
small, except the first which is very large ; it is followed by 3, 3, 3, 3, and
two plates. Interdistichals three or more. Ventral di.sk flat, with deep

248

TIIK ClUXOIDKA CAMKRATA 01" NORTH AJIKRICA.

intcrradiul depressions, surroundud by smidl nodose plates of rather irregular
nrrangeiueiit. Oral.s tuberculous; anus excentric.

llvrizon and Lwaliii/. — llaniilton group ; Ontario Co., and Thedford,
Ontario.

Ti/2}es in the New York State Cabinet of Natural History at Albany, and
in the Canada L rvey Museum at Ottawa.

THYLACOCRINUS Oehleut.

1S7S. OniLEiiT; Extr. dii null. Soc. Gool. dc Finiice (sur. 3) Tome VIL, p. 578.

ISi'J. ZiTTKi. ; Ilamll). d. I'liia'diit., Vol. 1., p. 375.

18S1. W, mid Si'. ; licvisiou I'ldicocr., rait II., p. 207 (Proceed. Acad. Nat. Sci., Pliilu., p. 381).

Calyx large, plates convex; anal interradius distinct from the others;
arms arranged in groups of four or more. Infrabasals five, small. Ba.xals
five, hei)tagoual ; their upper faces truncated, and each plate supporting an
interradiid. Radials followed by two costals, and these by 2X2 distichals,
which in turn support within the calyx several brachials of a third, and
sometimes of a fourth order. Arms heavy, long, simple throughout, and
biserial. Interbrachials numerous, arranged longitudinally in series of two
or three, with additional plates at the anal side. Interdistichals very numer-
OU.S, in rows of one or two ; interpalmars al.^o represented. Construction of
the tegmon and position of the anus imknown. Column, so far as observed,
pentangular with re-entering angles.

Distribution. — Devonian; France, and Hamilton group; Western New
York.

T///IC of the genus. — Tliijlacocrinus Vannioti Oehlert.

Jiitnarks. — T/u/ldrncrinus differs from lihodocrhius in having interdis-
tichals and interpalmars ; the former being very rarely, the latter never,
preserved in that genus. It also differs in the arrangement of the plates
of the anal side, in having four or more primary arms to the ray in place of
two, and in that the arms are large and simple throughout.

Thylacocrinus Clarkei w. and Sr. (nov. spec).

Plate XIII. FIrjs. ] la, h.

Calyx apparently globidar ; the plates very gradually and uniformly' de-
creasing in size upward.s. Infrabasals .small, and forniing a pentagon with the
points of the angles f^lightly projecting beyond the column; column attach-

RIIODOCRIXID.E.

249

mont stclliforni, somewhat concave, the margin surrounded hy concentric stria)
as in Jurassic Pentacrinidtv. Basals large, shghtly curving upward. Radials
as wide as liigh, of the same size as the costals. Disticlials 2x2, a little
shorter tjian the radials. The four lower palniars form part of the calyx,
the upper are free ; the fi.xed plates consideral)ly highest, hut decreasing in
height upwards; the three proximal arm plates suh(iuadrangular, the suc-
ceeding ones gradually turning from cuneate into bi.serial, meeting laterally
by a zigzag suture. Arms four to oach ray, simple throughout, rather strong
at the bases ; their length unknown. Interbrachials : 1, 2, 3, 2, etc., some-
what smaller than the adjoining brachials. Anal intcrradius wider, with
three plates in the second, and four in the third row. Interdistichals in
about six ranges, arranged in pairs from the first plate up. lnter])almars
three to four, arranged longitudinally in single file. Ventral disk and
anal opening unknown. Column pentangular with re-entering angles near
the calyx ; the joints of nearly eijual width ; the salient angles of the nodal
ones bearing a small tubercle.

Horizon and Locality/. — Hamilton group ; Canandaigua Lake, N. Y.

Ti/pc in the New York State Cabinet of Natural History at Albany.

licmnrh. — The species is described from a somewhat crushed specimen,
formerly in the collection of Prof. John M. Clarke of Albany, N. Y., in whose
honor the specific name is given.

, 1

DIABOLOCRINUS W. and Sp. (nov. geu.).

(Aia/3o\o«, the devil ; xpivov, a lily).

Syn. Motloerinui (in pnrt) — White, ISSO; Proceed. Nntiniinl Musoiim, Vol. II., p. 230.

SjMi. h/i-locniiii.1 (ill iiart) — S. A. MiLi.Eli, 1SS2; .lourii. Cineiii. Soe. Ni\t. llist., Vol. V., p. 117.

Sjii. .Irrhfurriiiiis (in purl)— \\. niid Sp,, ISS.'); Proceed. Acini. Nut. Sci. Pliila., p. 3-20.

Svii. Arch.nii-riiiim (in part) — W. aii[i Sr., 1S85 ; Revision Pala'oer., Part III., ]). 9S.

Syn. ArcliMcriaus (hi part) — S. A. Millkk, ISS'J; N. A. Gcol. niid Palu.'ont., p. 225.

Calyx deprcs.sed globular, with a wide and deep concavity at the bottom,
involving the infrabasals and large portions of the ba.sals. Infrabasals five,
small, but projecting beyond the column. Basals large, elongate ; their
upper hiilf directed horizontally or bending upwards; the upper faces broadly
truncated. Tladials not in lateral contact, being separated from each other
by one or more plates, which rest upon the basals. Costals two. Arms two
to the ra}'. free from the first or second distichals ; their structure unknown.
Arm openings very large, directed obliquely upward, and arranged in groups.

or.

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

Inturradial spaces wide, composed throiigliout of large plates, wliich connect
with tlie disk plates, or, properly speaking, pass into the disk. The large
plates between the radials arc frequently surrounded by small supplementary
or secondary pieces, which wholly or partly isolate them from the basals,
radials and costals. The second range of interradials consists of two, excep-
tionally three, pieces, the third of three ; the latter foiming part of the upper
margins of the arm openings. The anal interradius, which is wider than the
others, has three plates in the second, and four or more in the third row.
Ventral disk depressed conical ; composed of rather large plates, none of
them conforming to the general arrangement of orals, which are probably
unrepresented. Anus almost central, and at the end of a strong tube.
Column round or indistinctly pentangular, with a large pentalobate canal.

Dhtrihutlon. — The three species herein described come from the Trenton
group of Eastern Tennessee. In the same locality we found a fourth species,
but none of the specimens so fur obtained are sulliciently well preserved for
description.

Remarks. — We make our DtahuJocrimcs perpkxits the type of the genus.
Dtaholocrinus has closer resemblance to Lyriocrinus and Archwocrixiis than
to lihodocrinm, but is readily distinguished from both of them. In Lijriu-
criinis the arm facets are directed strictly upwards, the arms are single
and placed in a straight liqe with the walls of the dorsal cup; v'lile in
Dlaholocrinm the arms were apparently given off as armlets from tubular
j)rolongations of the calyx, and the facets are directed obliquely outward.
ArcliwucriHus has a more elongate calyx, the disk consists of minute irregular
pieces, it has no anal tube, and never supplementary pieces such as we find
in D. pcrpUxus. The latter is a feature that reminds us of Iktencr'r.uis, Xmo-
crinita, and Acrocrimts, in which a similar intercalation of jilates takes place
on a much larger scale.

Diaboloorinus perplezus w. and Sr. (nov. spec).
Plate XI. Figs, la, b.

Length of calyx as compared with its width three to two; pentangular
across the arm bases ; the dorsal cup more than twice the height of the
tegmen ; basal concavity wide and moderately deep, involving nearly the
whole of the basals. Plates convex, the larger ones bearing one or more
conspicuous nodes, the others a .single central one.

RIIODOCRINID^E.

261

Infmbnsols coinplotely hidden by the top stem joint, nnsnls large, elon-
gate, barely seen in a side view, longitudinally grooved nt the median line,
wiiich gives to the cavity a decidedly pentangular outline ; tlie angles of tlie
upper face truncated for the reception of supplementary pieces, wliicli in this
species are not only constantly represented but quite regular in their arrange-
nient. Costals less than half the size of the radials. Distichals still snuillcr
and free above the first. Arm openings in pairs; elongate. Interradials
1, 2, 3 in the dorsal cup; the first, which is nearly as large as the basals,
surrounded variously by from two to four supplementary pieces, two of them
abutting against the radials and basals, and two against the radials and first
costals. These plates vary greatly in size, being in some specimens very
minute, while they arc comparatively largo in others. In very large speci-
mens, when completely developed, the first regular interradial is surrounded
1)\- six plates — including the two regular interradials of the second row —
and by seven plates at the anal side. In cases in which the supplementary
pieces are small and imperfectly developed, the first interradials touch the
radials and basals. Tegmen composed of rather large plates without any
regidarity in their arrangement; the interradial portions depressed, those
concealing the ambulacra quite prominent. CoUnnn small, obtusely pentan-
gular; axial canal very large.

Horizon and Locality. — Trenton group, near Knoxville, Tenn.

Tf/jjcs in the collection of Wachsmuth and Springer.

Diabolocrinus vesperalis (White).
Plate XL Figs. Ic, d.

1B80. Rhoihcriims tenperalia — Wiiitk; Proceed. U. S. Museum, Vol. II., p. 259.

1S83. Rlioiheriiim rojuralis — AViiiTE ; Twelfth Ann. Rep. U. S. Gcol. Surv. Terr., liy Ilnydcii, p. l-.'9,
Plate 35, Figs, in, h.
Syn. Lifriorriiiiis icii/p/i/h — S. A. MiLLEU ; \S^2 (not Hull 1851), Cincin. Journ. JCnt. Hist., Vol.

v., p. 117, Plate 3, Figs. C,a, h.
Syu. hyrioeriiius inilptiis — S. A. MiM.ER; ibid, (privnte cd., Explnimtion of plnlc).
Syn. Ji-c!iii<icriiiii!< sctil/i/m — W. itnd Si'. 18'^5 ; Revision Paln'ocr., Piirt III., |ip. Ofi-OS.
Syn. Jichrrocrinm sciilpliis — S. A. Mii.i.Eii, 1889; North Anier. Geol. nnd Pala'ont., p. 225.

Calyx depressed subglobose, pentangular across the arm bases ; the basals
to one third their length forming a funnel-shaped concavity, of which the
infrabasals form the bottom part. Plates but very slightly convex, densely
covered by wrinkles or indistinct striae.

Infrabasals invisible beyond the column. Basals large, elongate, the prox-

262

THK CRlNOinKA CAMKUATA OK XOUTII AMERICA.

!
Ill

imal portions concave; tlio distal portions of tlio plates bending upwards;
the faces supporting the intcrradials broadly truncated. Railials sometimes
Rnialler than l)asals and intcrradials, their lower faeen decidedly angular.
Costals smaller than thurndials; the second shorter and narrower than the
first. Distichals to the height of the second plate incorporated into the
calyx, tlie succeeding ones free ; the plates siiort nnd semilunate. Ueguliir
intorradials : 1, 2, 3, the first nearly as large as the basals, the upper ones
considerably smaller; the supplementary pieces irregularly distributed among
the interrays, or aksent altogether. Tegmen as in the preceding species.

Ilurtziin and Locallf//. — Same as last.

'J'l/jx: in the National Museum at Washington.

]iiiiiiir/,s. This form was descril)ed by White in 1880 under the name
of li/i(iili>cn'iiiis nsjnrd/is, and it was stated that the specimen probably came
from the coal measures, thirty miles west of Humboldt, Kans. S. A. Miller
rcdeseribed the species in 1882 as Lijrioci'inm scnlptm* giving " Tennessee "
as locality, and '"Niagara group" as the probal)le hori/on. The specimens
from which our figures are made were collected by one of us in 188.", from
rocks of the Trenton group at Knoxville, Tenn., where they were found
associated with J/i/bvrn'inin and otiier typical Trenton lornis. We have com-
pared these specimens carefully with White's type o£ JtlKiilorrinnn I'csjtiraHs in
the National Museum, and also with Miller's Lijiiocrinua sciiJjitiis in his own
collection, and not only find the various specimens specifically identical, but
think it most proljabie tiiat they ail came from the same locality.

Diabolocrinus hieroglyphious w. ami Sr. (nov. spec).

PI :/c X. FSf/s. Sa, h. c.

Calyx globose ; basal portions deeply depres.sed, forming a narrow fun-
nel-shaped pit, of slightly pentangular outline, which enclo.ses the whole of
the infraba.sals and one fourth of the ba.sals. Arm openings directed ob-
liquely upwards, and invisible in a dorsal view. Plates of the donsal cup
covered with numerous elongate nodes, of irregular form, which give to
the surface an appearance sugj.'estivo of being densely covered with hiero-
glyi)liics. The rays are marked by consjjicuous ridges following the median
line of the plates, and similar ridges pass out from the centre of the radials

• Tt wns described in the .Iniinial of tlic Ciiiciiinnfi Society under tlie imii.c of lyriurriiiua sciilptilia ;
but Stiller, on finding the nanie preoccupied, cimuged it in his private edition to L. tmt/ituf.

IKfUDOCUlNID^K.

2fi8

to ndjoininj,' ImHiils, tlio latter fonniii)^ upon tlic hiiiTih-o ii well ili'liufil fivc-
myed .star, wIiomo Niiliciit angles altoinatu with the angles of the hu.sal
concavity.

IntniltasulH Hninll, and ahnont completely covered hy the upper joint of
the column. BasalH largo, elongate; spread out horizontally, except their
lower ends, which form the sides of the funnel-shaped pit. IJiidiaN large,
their lower faces sharply angular. Costals smaller than the radials; the
second considerahly smaller than the (irst. Distiehal-i free from the second
plate; very short. Arm structure unknown. Interhraehials : 1, •_». ;., 2. 1.
with variations of three plates in the second, and two to four in tiie ihini
ranges; the first plate large, heing next to the ha.sals the largest plate of tho
calyx ; the plates of the .second row considerahly Bmaller, especiully when
there arc more than two plates in that row. The supplementary interradials
are less frequently represented than in the preceding species, and rarely hy
four plates to tho interray ; hut there is scarcely a specimen in which there
is not at least one of them introduced at one side. The plates of the third
row arc placed between the arm bases; the succeeding ones form part of the
ventral disk. The anal side is wider and the jjlatcs more numerous ; there
being three or four in the second row, and four or more in the Micceeding
ones. Ventral disk aImo.st as high as tho dorsal cup; composed of rather
large convex plates of nearly uniform size. Orals cannot bo identified, the
whole ventral pavement consisting of the same kind of irregular!}- arranged
plates. Anus nearly central, extended into a strong tiilie. Column near
the calyx apparently slightly pentangular; central canal very large and
pontalobato.

Horizon and Lornlltij. — Trenton group ; near Knoxville, Tenn.

Ty^wH in the collection of Wachsmuth and Springer.

liniiarl's. — This species is distinguished from tiic preceding one by the
different form of the calyx, the peculiar s'tyle of ornamentation, and by the
irregularity in the distribution of supplementary pieces in the interradiul
series.

ARCHiEOCRINUS W. and Sp.

18S1. W. nnd Sp. ; Revision Pnlivorr., I'aii IF., p. 1^9; iiImi rnicccd. Aend. \ot. Sci. I'liila , p. .'1(13.

18S5. AV. nnd Sp. ; Hi^visicin I'ldicdpr., Part III., p. 90; I'rnpccd. Acad. Nat. Soi. I'liila., p. IflS.

18S3. S. A. Mii.i.Kfi ; Jmini. rinciii. S<ic. Nat. Hist., Vdl. VI., |i. 217.

1SS9. S. A. MiLLEu; N. Ainer. Gcdl. and Palipont., p. 2ii.

Calyx large, obconical or subovate ; plates smooth or variously orna-
mented ; those in a radial direction marked along their median line by

loi

Tin: riMNolDK.V CAMKKATA OF NOKTII AMKlMf'A.

oliHciirt', lliittiiicil ridgi'H, wliicli j^row moro conHpioiioux on n|i|mi:icliiiij^
tliu anii.«. liilViiliaMiilH ;<iiiull, iiuclv cNtciiiling ho^uiid tlio ooliiiiin, nmi
rL'.>tliiig, ii« II rule, wiiliiri a CDiu-avity forinril by tliu lower part of lliii
l)a-'al.M. Ilasalx lie|ila^'oiial, their upper I'aees Iriiiieated. KadiaLi in tliroo
of llie rays peiilagoiial, in tiie two posterior oiieM frecpiently liexiij^oiial.
When lliuro uru no pahnurrf the throe to hIx lowur dintiehals tnkf part in iho
eidyx, and ihu nufeeeding ones arc freo urn» phiten. Arum chort. xleiider,
liraiiehinj,' ; eoinpoM'tl of two rows of ciineifonn pieees, alternately arranjred
and inieiioeivin^. lnlerrii<lial areas cuiiHtrncted of nnnuTons platen; the
platu lii'iween the radialn, whieii is nineh 1ar^a>r than the othorn, is t'ollowod
ut tho regular sides by two interbraehials in tlic Rocond row, nt the nnal side
by three, but there is no median ridge or cuntiiiiious row of nnal pintes.
Tile upper interbraehials Cdnnect inipereeptibly with the plates of the disk.
Interdi.'^ticlial.s always represi'iiled. \'entral disk, as observed in .{.(hxlilmitiis,
ooui|)o.si'd III' small irregular pieces, which close over the ainl>ulaera, except
ni'ar the outer margin of the integument, where their covering pieces arc
exposed. Colunm round, the edges of the nodal joints largely projecting
over the iuternodal om-s ; axial cannl large, peiitalobate.

DislrlliiiHiiii, — I'robably restricted to the Trenton group of Americn.

Tij/H' of the genus: ArcJidom'tnis lticinii>mi>i (Billings).

lictiiitrks. — ArvliaocrhiKH has close nllinities with Jihoihcriiivs, and it is
somewhat dillieult to point out tho structural difTerence-s, The calyx of the
former is relatively larger, the arnm shorter, and it has but two interbraeh-
ials in the seconil row ; while lilimhirriiniK, ns a rule, has three plates in the
sicond and all succeeding rows ; and the anal interradius very often has tlio
same arrangement of plates ns the others.

(jlilj)ti>rr!iius iiiarijiiiatus Hillings, which in 1881 we placed under Arrhtro-
(•r!/iv», proves to be a monocyclic form, nnd will have to be referred back to
(rli/j)t()rriiui.i as a somewhat aberrant type. Whether lihodocrltiiis axjwrnfiis
Billings belongs here, caimot be ascertained from tho imperfect state of the
specimen. Li/rloerlnits nculptus S. A. Miller {Archaocrliius sriilj)fi(>i W. & Sp.)
is n synonym of lihoihcrinus ve»pcralis White, which has been placed nnder
the genus Diahohcrinus.

:*l

■|i

uiioixkiumd.t:.

255

Arobnoorlnuii laounoiui « !'iui,inuii).
i'lati: X. Fi<j. 1.

1837. (ll^filiicriHiit liicHuiinii — lllM.lN<i»; (ii'ul Ur|i. CuiiimI.i (lti|i. nf I'lnKi), |>. lidl, iiKm iliiil. ISJO,

DtLMuli! IV., |>. ftl, I'lalr H, FiKs. 11 n-f.
ISSl. .iivhinii-riau) liirMiioiiiii — \\ . ami Nl' ; llrvi'iiiin I'lilifncr., I'liil II , p. I',)ll.

Till' only known Hpocinion is Hotnowliiif criiHlit'd, luul its cxiut (nrin ciin-
not 111' iiMCi'itaini'd, hut it was piolmlily miligl()l)()f<i'. 'I'lie niciliaii line of tlii
rnys is followed by lidj^'i'M, wliicli j,mo\v qiiito pioiiiiiifiit ii|i(in tin- ilistjclinls.
and till! smface of tlio pliitcH is coniplotcly covered l»y small riiji<iM' iiit.^i and
wiinklcM.

Iiifral)ii.«<alH very niinnto, not visilde from a Hide vit'W. Ha.xalx nmiHnally
larjjo, the liirgest |ilate.>< of the ealyx ; tlu'ir truncated iipper nide very wide.
Kadials .slij^htly Niiialler than the Ita.xalH, the two fafin^' the posterior side he|v
tngonal, the others pentajjonal, all Himrply nn;,'nlar helow. Costals rather
nmall. The three lower dintiehalH take part in the I'ahx ; they are small
and curved like free arm plates. Arms ten at their oriirin, rounded, laflier
delicate, hifiircating once or oftener, the branches diveijrent, and cninposed
of short interlocking pieces. Interbrachiali large ; those between the radials,
which are almo.st as large as the ba.sals, ri.se to the middle of the .second
disfichals, and are followed by two plates in the second range, and others
above ; anal side wider, plates arranged : 1, ."), 4, etc. Column roiiiid, tap-
ering considerably downward ; the nodal joints very high, even those next
the calyx, which are twice as wide as the intervening ones, and thick and
rounded at the edges; the internodul joints comparatively short. At six cm.
from the calyx the internodes contain five joint.s, and this number upparcntly
does not increase in the lower part of the stem.

Iloi'hon mid LocnUtij. — Upper part of Trenton group; Ottawa. Canada. -

Tiii)c in the Canada Survey Mu.scuni at Ottawa.

»l

I •■

Archseocrinus pyriformis Billikos.
Phde X. Figs. Sa, h.

1S57. Thi/mnorriiim (RMorrinim) pyri/ormit — 'R. Hii.i.iNos ; Oco]. Ticp, Tanndn (Rrp. of rrogr.), p. 20:1
1S59. ll/iii(/iii;-iiiiiii iii/ri/hniii.i — K. Uil.l.lNiis; ibid., Dfcadi- IV,, p. (ll, I'lali' (i, Fiifs. \(i-i/.
1S81. Ari'liirni'riim.i pi/riformin — W. mid Sp. ; lievlsion Pnlirorr., I'arl II., p. lOH.

A largo species. Calyx obconical or pyriform ; one fourth higher than
wide; greatest width across the second disticlmls, slightly contractinjr r.liove.

lioi,

TllK tlMNOIDKA CAJIKKATA OK NOUTII AMI'.HICA.

Suil'aco 111" pliitcs Miiuolli (ir finely j;nuuilosc ; tlio radial plates .soniewhnt
elevated aloiiy their median lines; sutures distinct, but not grooved.

Infrabusals laryer tiian in any other known spceies of this genus, and
plainly visible from a ; ide view, rorining ii shallow cup. Uasals large, a little
higher than wide, upper face narrowly truncated. ISadials and co.stals of
similar size, the lormer pentagonal, the two .osvals hexagonal. e.Ncept in
the posteiior rays in which the second is heptagtmal. Distiehals to the
height o^' the sixth plato incorporated into the calyx, gradmilly decreasing
in height ; the first as large as the second iMterl)rachials, the upper one
resemliiing a good sized arm plate. Arms short, delicate, twice bifurcat-
ing; couiposei. from their ba.ses up of small triangular interlocking jiieces.
Interbrachials : 1. 'J, 2, 2, etc., rarely 1, 2, 3, ?>, the lower plate heptagonal,
larger than the radials; at the anal side there are three plates in the second
and all succeeding rows. Interdistichals nine or more, rather large. Struc-
ture of ventral disk and anus not know.i Colmnn circular, slightly tapering ;
in the upi»er part of the stem the nodal joints project, but further down have
the same size as the others.
-~— Jliiriiiiii (iiiil Lucdli/i/. — Trenton limestone; Montreal, Canada.

'J't/jiiK ill the Canada Survey ^luseum at Ottawa.

1S.-.7.
18S1.

AroheeocrinuB mic^o^aBali8 Hillisos.
Plate X. Fli/x. Ja, h, c.

Thy«iiiniTi»iiii (R/iD'locriiiin) inifrubnmtlis — K. Hii.i.iNfiS ; Giol. Iti'p. Canada (Rep. of Proirr.)

p M\; ;il>c) ilii.l., Decade IV., p. (W, I'lale fi, \'\f. 2.
Airh,rwriiiu.t mii-ruhimalis — \V. ami Sr.; Itevision I'aliEOCr., Part 11., p. I'JO.

Smaller than the preceding siiecios, the arms proportionally longer.
Calyx oliconical, truncated at the lower end, sides .slightly- convex. Surface
beaut if nlly ornamented with parallel, radiating stritv, proceeding from tho
middle of the plates to adjoining ones, and broad, rounded ridge.«, starting
from the middle of the radials and passing up the costals and distiehals into
the free arms.

Infraba.sds minute, forming a pentagon, which rests within the ba.sil con-
cavity and is covered by the colunni. IJasals large, heptagonal, niore than
two thiids of the plates visible from a side view, the lower end bent inward
and forming, togrihcr with the infrabasals, a good sized concavity, with a
thickened rim arc nid tho edge; tho upper faces narrowly truncated. Radials
as large wa the ba.sals, distinctly angular below; the costals somewhat smaller.

lUIODOCRINin.K.

257

HI s

Tlie lower diHtichals (o the nmnbcr of «evoii or ciglit take pa in the calyx;
they decrease rapidly in size, the lower one being comparatively large, bnt
the ♦'Muth is but little larger than the free plates ; the plates above are tri-
angular and interlock. Arms long, rather stout at their bases, but tapering
gradually to the tips where they are quite thin ; they bifincate twice or
oftener, and are composed of two rows of plates witli parallel faces. Regu-
lar interl»rachials : 1, 2, o, o, followed by numerous smaller plates; the
anal side has 1, .'), 3, 4, t/r. Of interdistichals as many as fourteen pieces
have been ol)st'rvcd, tiie lower one resting upon the first distichais. Con-
struction of the ventral disk and form and position of the anal opening
unknown. Oolumn roimd, tajjcring downward; the upper part composed
of alternately large and small joints with angular edges; but at about three
inches from tiie calyx the internodal joints reach the width and height of
the nodal ones, and the edges lose their angidarity.

lliivi.viiii mid LiwalUii. — Trenton limestone ; Ottawa, Canada.

The figured specimens are in the collection of Mr. John Stewart of
Ottawa. Tyiic in the Geological Survey Museum at Ottawa.

ArchSDOcrinus desideratus w. «. i!ii,i.iN(is.

riaU: X. FiffH. 4a, b.

]>«S:i. Vi. n. Illll.ixr.s; Trans. Field Xntiir. f'luii, Oltawii No. fl.
1SS5. \\. aiul Si'.; lt.\isi(iii I'aliL'oer., I'arl 1 1 1 , p. 'JS.

A rather lar'^e species. Calyx depressed globose ; basal portions deeply
depressed, forming a broad funnel-shaped pit, much wider than the ciioum-
terence of tiie stem, and deep enough to contain five or six stem joints.
Plates convex, without ornamentation or other markings, except ol)scure
elevations — a kind of broad, roiindod ridges — following the median line
of the rays, and branching to the ba.sals.

Infiabasals small, hidden by the column. Basals large, twice as long as
wide; the lower half of the plates forming the sides of the ba.sil pit; the
upper Iialv<>s. which l)end abruptly upward and outward, occupy the sides
of the cup. Iiadials pentagonal, almost as long as wide, their lower faces
forming a sharp angle, which extends down to the margin of the basal
concavity. First costals hexagonal, as wide as the radials, but shorter ; the
second .shorter and narrower than the first. Distichais 1x2, all incor])c'ated
into the calyx, and comparatively small ; they are rounded exteriorly, and

3.1

I I

258

THE CRIXOIDKA CAMERATA OF NORTH AMERICA.

I !

tlio two scries of the siiine ray are so nearly in contact as to leave but a nar-
row space for the insertion of interdistichals. First distichals somewhat
longer than the succeeding ones, wiiich are (|uite short; tiie fourtii is axil-
lary, giving off to the outer sides a row of pahnars, whieii are free from the
third or fourth plate; to the inner side two jjalmars, of which the upper
is axillary, and supports two arms, making three arms to each side of the
ray. Arms subcylindrical, stout, very little tapering; composed at their
bases of a few (juadrangular pieces, followed by euneate ones, which deeply
interlock. Pinnules strong, given off nearly at right angles, and composed
of short joints; the first very much stouter than the others, given off from
the second distichals, anil wholly or partly incorporated into the calyx,
Interradial spaces wide, the upper portions rather deeply depressed. The
plates of the two lower ranges verj- large, the first being the largest plate in
the calyx. There are probably five or six rows above, but the number
of plates in each row is extremely variable; the third contains variously
from three to five plates at the regular sides, and from four to six at the
anal side; the fourtii row has as many as eight in some specimens. The
first plate of the anal side is somewhat larger than those of the regular
sides; it is octagonal, its upper angle being slightly truncated for the recep-
tion of a narrow anal plate, which is placed between two interbiachials.
Interdistichals from one to three, longitudinally arranged. Ventral disk
rather Hat. composed of veiy small irregular pieces; the aiuljulacri) subtog-
minal, except near the arm bases, but the course of the ambulacra is marked
by high ridges wliich diverge to the arms, anil form deep depressions all
along the interambulacral spaces. Orals apparently unrepresented, the sum-
mit being covered by similar .small plates to the rest of the disk. Anal
opening subcentral, at the top of a well defined protuberance. Cohunn
round ; axial canal large, pentalobate, the outer ends of tlie lobes widest
and truncated.

- Jloiivon ami Locaiitif. — Trenton limestone ; Ottawa, Canada.
Ti/pi's in the collection of Mr. Walter R. Billings, Ottawa.

RHAPHANOCRINUS AV. .iml Sp.

18S5. \y. nml Sp. ; Revision, Part III., p. 9« (I'locLfil. .\rail. Nat. Sci. riiiln., p. 320).
18S7, Okim.kIiT; Aim. dcs Spi. Ciro!., T.inir XIX., I'lalp I , Fii:s. 10, 11.
1889. S. A. .Mii.i.KK; NdiIIi Aiiicr. (Icul. and I'alii'oiil., p. 277.

Sy, <:iKj!'m-riiiiia (in pall) — Wau OTT ; 1'<8H, Xi'W Spec. Foss. of the Trenton group of New York,

p. 2 (At)slr. rrnin tin- .'(.'>( li Urp. New York State Museum Xat. Hist.),
Sjn. ffA/;)/oi'/7>«t (ill part) — S. A. MiLi.KK; Juiirn. Ciiiciii. Sue. Nat. Ilisl., Vol. V., p. 37, and
ibid., 1SS.3, Vol. VI., p. 221.

IIIIODOCRINID^E.

lo9

Allied to Archwocri'iuis, but arms iiniserial and not bifurcating. Radial
ridges generally well developed. Infnibasals sinall, not vi.sible from a side
view, and generally completely bidden by tbe column. IJasals largo, bexa-
gonal, tbe upper face truncated for tbe reception of tbe first interradial.s.
Hadials and second costals of .similar form, but tbe former angular below,
tbe latter angular above. Arms ten to twenty, free from tbe di.sticlial.s or
palmars according to .species; tbey are .xtout, long, .simple, and composed
of quadrangular pieces witb strong pinnules. InterbracbiaLs and interdis-
ticbals numerous. Structure of ventral disk, and form of tbe anus unknown.
Column large and round.

Dltslri(iiill'ii). — IJotb American species arc from tbe Lower Silurian. Oob-
lert described a species from France under tbe name Ii/ta/>/i(aiorrini(s U'ur/is-
iiiit/hl, wbicb came fiom tbe " Devonien inferieur," but tbis is apparently
not a typical form.

T>/j)e of tbe genus: JiJuijihanocrimis subnodosus.

Rhapbanocrinus subnodosus (Wamott).
rtnh: XI. F!,j. 2.

ISS:!. (7/yp/orriiius {'■) Stt/moilosus — Vt'\ur,TT, 3jlli Uc|i. N, York Sliitc Mils. X.it. Hist., p. 20S, TLilc

17, I'll,'. 3.
1SS5. IHiip/iunorrimis .lubnitiloriin — W. niid Si'.; Hcvisinii I'ala-ocr., Part III., p. 90.

Calyx of medium size, obconical ; interradial areas depressed. Hadial
ridges well defined and marked by a small node in tbe centre of eacb [date ;
tbey pass down to tbe middle of tbe radials, wlierc tbey meet witb similar
ridges from tbe two ailjoining basals. Tbe iuterradials luive also a central
node, from wbicb obscure ridges pass out to tbe margins of tbe plates, wbere
tliev meet witb ridges from adjacent plates.

Infrabasals completely covered by tbe colimin. Basals very largo, fully
as bigb as wide, sligbtly truncate above. IJadials beptagoual, larger tliiin
eitber one of tbe costals. decidedly angular below. Arms ten, ratber stout,
simple, tbe lower plates incorporated into tbe calyx, tbe second and all suc-
ceeding ones piniude-bcaring ; tbey are composed tbrougbout of compara-
tively long, quadrangular joints, witb stout pinnules, placed wide apart.
Interradials : 1, "J, 3, 3, and two or more rows above. Interdisticbals : 1, 2.
Xotbing is known of tbe ventral disk or of tbe anal opening. Column
round, very large.

■g— ^■«^---

260

THK { HIXOIDKA CAMKRATA OK NOIMII AMKUK V.

II(iri::oii dud Localihj. — Upper portion of the Trenton liniostone; Trenton
FaUs, N. Y.

Tijpc in tlie Miiwuni of Conipurativo Zolilogy, Cambridge.

Rhaphanoorinus soulptus (Mn.t.Kit).
Plate X. Fi(j. 3.

1882. GlnitnrrinHi sfHlplm—^. A. Mii.i.i ii ; Joiini. C'iiicin. Sic. Nnt. Hist., Vol. V., p. 37, riiilp I.,

Fi^'. i.
lSS:t. di/iilui-riiiHii m-iiliitii' — ^. A. .Mll.I.Kli; iliiii , Vol. VI., p. 22t.
l^S."l, (lli/iiliicriiius nfiiliiliin — W. ami Sr. ; Kcvisioii I'lilirnrr. I'arl III., p. 1111.
ISS',1. (llj/iilofi-iiiii.i nfiiliiliis — S. A. Mii.i.Ku; N. Aimr. (Ii'ol. and i'lila'cuil., p. 218.

Oiilyx .suhglobo.'^o ; interriuliiil .spaces deeply depres.^ed, especially the
upper portion ; section across the .second costals sharply pentagonal, across
tiie distichals decagonal. Radial ridges quite prominent, angular, stronger
toward the sntures than at the median portion of the plates. Somewhat
smaller ridges pass into the hasals, forming deep triangular depressions along
their sides. Other riilges run from the radials and brachials to the inter-
radial plates, dividing the whole surface into munerous impressed triangular
areas.

Infraba.sals almost covered by the column. Basals of medium size, pro-
duced into angular processes, which jioint downward for a short distance
idong the sides of the upper stem joints. Radials and costals al)()iit as wide
as long. Distichals three, almost as large as the costals. Tlie iilates of the
tiiii'd order su])port the arms, of which there are twenty; they are long,
gradually tapering, and composed of (piadrangular joints which become
slightly cuneate in the upper parts of tiie arms. The four to five lower
joints, which are ccm.siderably the largest and shaqdy angular on the out-
side, take part in the calyx ; the succeeding ones are free, much shorter, and
rounded. Pinnules long and slender. Interradial spaces deeply de))res.-e(l
between the disticiials ; the j)lates arranged: 1, 'J, .'],.'). t/c The anal side,
which is a little wider, has a few additional plates, but no anal ridge. Inter-
distichals: 1, 2, 1. Structure of ventral di.sk imknown. Colunni roinid,
slightly tapering downwards, the nodal joints, near the calyx, wider and
considerably longer than the intervening ones, but at two inches below the
latter reach almost the same size.

Jfi>i-!.-(>ii mid Liividitij. — Upper part of the Hudson River group ; Warren
Co., Ohio.

7' I cs in the collection of I. II. Harris, Esq., at Waynesville, O.

RHOnOCIUNIDvE.

261

licmrirks. — Ii/tajiJianocrlitiis f<ni/j)tus Avas ilcscribcd as monocyclic, and
referred by S. A. Miller to Gljjitiwrhut^. The inlViibasals arc only seen
as small dots around the column. The species is readily distinguished from
allied forms by having knife-like ridges upon the fixed brachials; while the
back of the free brachials is perfectly rouiul.

LTRIOCRINUS nur..

\V,i. Ham,; firol. Rrp. N. Y, rnliwiuldliK.v, V.il. II., p. 197.

1857. I'liTKT i Triiilr dc ralrmit., V<il. I\'., p. 'AiW.

l.sn-i. l)r.iAUiii.N aiul lliri:; lllsl. Niitiir. clis /nDph. Ktliliiod., p. 1 111.

180(1. SiiiMAiin; Tiiins. .\ciiil. Sci. fS(. Lniiis, Vul. II., p. li/'J.

1807. IIai.i.; :JiiiIi Krp. N. Y. Mali' Call. Nat. Hist., p. Si.").

1879. IIai.i.; is\\\ Hep. N. Y. State Mus. Nat. IliM. (iil. i). p. l.'iO.

1881. W. and Sr. ; UcvisiDii I'ahi-iicr., Tart II., p. -MW (I'riKTcd. Aiad. Nat. Sci. I'liil'i., p. .'i?;).

18S1. Mali.; lltli .\iiii. Hep. Indiana l>v ('ull.l. p. iiCO.

1889. S. X. Mii.i.Kii; Ninth Ann'r. (Irc.l. and ralinrnt., p. a.'jS.

Svn. Mnrniiplocriiiim (udt I'liillips) IIai.i.; isi:i, (iced, till Distr. New Yiirk, p. 11 I.

Svii. It/iuilucniiHn (mil .MiIUt) IIai.i., ISOIl; Trans. Alliany liisl., p. I'JS.

Calyx deprcssed-globoso, more or less flattened to the middle of the
radiiils; symmetry almost perfectly pentamermis; plates heavy, their s^lrfaee.■^
smooth or finely granular; ventral disk not rising above the dor-sul cup; arm
openings directed upwards, placed at the ujipcr margin of the disk. Infra-
basals five, very ,«uiall, abruptly and deeply depressed and concealed by the
column. Ba.sals five, of uniform size, either all hexagonal and supporting
upon the truncate upper face the first interradial plate ; or (piite frequently
one or more of them hexagonal, and angular at the top. Costals two; large.
Two of the distichals enclosed in the ciilyx. Arms two to the ray, rising in
a straight lino with the sides of the ctdyx; simple, .strong, biserial, two of the
interlocking plates fi'ei|nently in the calyx. Inlerbraehials four, in three
rows; 1, 2, i. Anal side generally not distinet, but exceptionally it lias
a special anal plate in the second row. I)i-k Hat, somewhat depressed in the
interradial regions; composed of a great number of .xlightl}' convex, delicate
pieces, iiud well defnu'd orals. Anus subceiilrid, probably tit the end of a
small tiilie.

Column of less tluin lueiliuiu size, round; axial canal small.

Disfrihiitioii. — Upper Silurian. America ami iMirope.

T///H' of the genus : /,i/n'"rriiiits (hicti/hn' Iltill.

Jicinnrka. — 'i'lie name /.>/n'"('riiins was proposed I'ov t\ species from the
Niagara group of Lockport. which had been described under J/arsnpiorniiux,

262

TIIK CHIXOIDKA CAMKHATA OK NOIiril AMKKIC'A.

niul was Hupiiosed to liiivo but one ling of pliitcs bciieiith the riidials.
Anotlier spt'cios, cloarly of the wmu' goiui.x, wii.s iiltoiwurils rtfenocl l)y Hall
to lihvdocr'um. In the construction of the calyx L^/riucrinn. apiJioaclics
Ji'i/iiilumiwx, wliicli, liowuvcr, differs very e.x.senlially in the arm structure.
S. A. Miller's L//rmrmis ncit/plus, which in the Hcvi-ion, Part II., we placed
j)rovisionalIy under Arc/uewriiiHs, belongs to JJiiiMicrluiis, and is identical
witli J). viK/icni/in White.

In this genus we have a good illustration of the exceptional variation
from the characteristics of a group, which maybe met with among individ-
uals lieh/iiging to it. In L. iluc/i/lus the first intcrradials often touch the
basals only at the anal side, while in L. niclma, they rest upon the ba.sals at
nil live sides. Again, in the fc-nur species there is generally an anal plate
between the intcrradials of the second row, while in L. mclma that plate is
scarcely ever represented. Departures of this kind within n genus in respect
to characters wliich have always been regarded as of the utmost significance
for distinguishing fi'n.ilies and genera show how idle it is to expect absolute
accuracy in i!i. separation even of very important groups.

Lyriocrinus daotylus Ww-i-
Plate XI. Fiijii. Su, h, c.

',U^ m'< r»,~ i, ■■■!;■■: il,irf,//iit — II.VI.I.; (!(■(.]. Hep. Uli HiMr. N Y , ]). Ill

. ,:i2. Zvf. •/.,,.,/• ,,W,-«.«— Mali.; ruliionl. N. V., Vi.l. II., p. W. imi.! tl, Figs. hi-y.

1881. LyriorfiHtjii Jaclylu* — W. "i"! Si-.; Ucvisimi raliiMipi-., I'lirl 11., ;>. iO.'i.

Calyx; semi-globose: basal regions llatteiied, tlie centre abruptly dc-
pres.sed for the reception of the column. Surface of plates smooth or finely
corrugated. Infrabasals very small, restricted to the bottom of the colum-
nar concavity. T.asals large, four of them angular above, that of the anal
side truncate. Uadials wider than high, larger than the costals, slightly
touching each other laterally except on the anal side. Arms ten, simple;
heavy at their bases, tapering upwards to one half their former size. They
are composed from the calyx up of two series of alternate plates with parallel
transverse faces, and have a shidiow groove along the median line ; then' two
])roxiinal plates incorporated into the calyx. Interlnaehials : 1. '.', I ; those
of the first and second rov . large ; the lower one almost touching the basals ;
the upper one smaller und somewhat inllected at the upper end, resting
between the lower nr.a plates. Another ;-n all pli'e is placed between the
distichals so that the arms are separated ar. oiie side by an interbrachial, and

RHODOC'RINID.K.

2G3

at the other by nn interdiHtifhnl. The first pliito of the nnnl side, wliich
toiiclies the biisals, is hirger, and is geiieniily followed by three plates in the
second row. Coluiiin round ; composed near the calyx of nioderattly high,
thicker, and thinner joints.

J/iirixoH awl Loidlili/. — Niagara group ; Loekport, N Y.

Ti/iwn in the American Museum of Natural History at New York.

m '

Lyriocrinus melissa (IImi.).
r/u/c XI. Flux. 4,1, !>, c, (/, <■./.

1803. RlinilorriHHt rnelium — IIai.i.; Trims. Allmiiy lii'.t , |i. MIS (Abslr., |>. -J).

1870. RliiiilturiiiMn (l,iriiii-ii)iii«) iur/i<xii — llAi.r.; iH{h lti|i. N. V. Slalc Mils. Xal. Ilisl. (Mus. edit), ]>.

i:t'.», I'lulr 1,-., Fiirs. ls.>7.
1881. LyriijiviiiHi m,li»ii — \V. mill Si' ; Ucvisinii I'liltcoor. I'liil II., p. •H)j.

Calyx dopres.sed, nearly twice as wide as high, distinctly flattened to the
top of the radials, then curving rapidly upwards initil llie ^ides of the upper
part are at right angles to the truncated lower part. Ilasal portions foiining
a deep pit, which is surrounded by a pentangular rim, interradially arranged,
and having a triangidar node at each angle. Surface of plates flat, Hmootii
or finely corrugated.

Infrabdsals very small. eoiipeide(l by the column. Rasals elongate, gener-
ally truncated at the upper face, the lower hall'of the plates eurve(l inward,
forming the sides of the concavity, the upper iialf hori/ontal. Hadials large,
wilier than high. Both costals hexagonal, the a.xillary one snuiUer. its tipper
angle truncated, supporting a small interdistichal ; the sloping faces support
2x2 large distichals, which are followed by free arm plates of the .sune
order. Arms ten. equidistant ; tliey are stout, long, tapering, aud ('(uui^osotl
of sliort pentagoi\al pieces ; tlieir pinnules long and closely arranged. luter-
brachials: 1. 2, 1. 1; the first as large or larger than the raflials. resting
against the truncate upper fiices of the ba.sals. Anal side generally not (li.x-
tinct ; but it has excoptionnlly a small additional jdafe in the second row.
Ventral disk almost flat, barely rising aliove the dorsal cup. Interambu-
lacral spaces .slightly depres.sed ; orals well developed, twice as large as any
of the other disk plates, and more convex. Anus sulK'entnd. very wide, and
apparently connected with a tube. Column uniformly cylindrical, the edges
of the nodal joints marked by a continuous row of small noiles.

ILiyhnn mul L<ir(t1ll>/. — Niagara group; Waldron and Ilartsville. Ind.

T'lpr-'f in the American Museum of Natural History, New York.

; !

raa^^^^^^^^amr^

lii

MKLOCiaNID.K (RoKMKit) 1855.

Monocyclic. Lowkii iiu.uiiialh, with wkll dki-inkd iNTKiaiUACiiiALs hetween them,

KOIIMINU A i:\UT or Tin; UOltSAL cur. RaUIALS in contact all AIIOUNI).

Aiutlt/nit of the Qetura.
I.

TlIK MVMMKTIIV OK TIIK DOHSAL Cl'l' DlSTl'KIIKD MY ONK OK MOHK

ANAL ri.ATKS MkLOCKINITE.H.

A. 1!a.sai..h KivKj ctPsrAi.s nvo.
a, Fir»t eiialiil hexnijimul,

Aniisuinscriiil ; intcrbradiials and intprilistichals numor-
oiis. Vfiitral disk comiiosuil of very small, iru'gulur

]il!itos. Hasiils siiiull Ohjptoerlnus,

Arms Msorial, basals vuiy largi', otlicrwisu ri'si'iuMiiig

(flyptm'rhtiia I'eriijIyplorriniiK.

h. F'trnt costal ijuatlrainjiilai:

Arms uiii.serial ; iiiterbrachials fowj ventral disk com-
posed of largo plates StellJiacriitus.

U. Hasals kouk; costalm two,
a. Fimt costal licxwjonal.

Arms uniserlal, arranged in gronps j simple or bifurcat-
ing, distieliiils two to fo\ir, calyx of moderatii si/.n . . Mariacrlnus.
Arms long, braiicliing often ; palmars and arm joints
very short, deeply interlocking. iJisticlials live and
upwards. Calyx very large; lower palmars partly in-
cluded in dorsal cup, interbraehials very numerous , Scypltocrlnus.
The rays extended into live tubular trunks, from which
biserial arms are given off frouj the outer sides all the

way to their tips ileloerinus.

<'. Hasals tiikek ; costals two.

Arms biserial, simple from their origin; interbraehials

few, an anal plate interposed within the first range . Macrostylocriniis,

IT.

Symmetry of douhal rrr rxDisTUKiiEi) iiv anal J'LAtes .... Dolatockixitm.
A. Basals koi-r; costals two.
a. Afm.i hitrrinl.

Arms siniiile ; arranged equilatorally around the calyx ;

base obconieal Technocrlnus.

Arms dichotomous ; basal eup inverted; interbraehials

largo Corymbocriiins,

H. Hasai.s thkkk, small; costals two, the must wi adranoclak.
«. Anns s!>iij)/e.

llr

I'l

MKI.OCIMN'IIK'E.

260

Arms liinnriiil. Dorsal cup giilttiirliiiiato I'lttelliucrlnui,

AriiiH iiiiisi-riiil ; dorHiil i'ii|) <li'|iruH8e(l ; intcrhruvhiiila
tew, liiii^iliiiliiially urniiiK'*'))

C. nAHAt.M I.UIliK, |-|lllll,\lll,V TIIKKK, AM IIVMINKIt.

a. Con/lilt two, the Jir»l ijiiiiilruiii/iiliir.

Iitlevbtiichialt few.

Dorsal cup HulH'yliiiilrical ; liaHals aiul radials very large,
ilisticliali) Hiiiall ; ariii.s unknown

Calyx ilc|>ri-H.s)>(l-NuliKlol)o.si'; liasaln Hniall, inti'iliracliials
fuw, the tirHt t'xtrt'Mifly huh'i- Arms liiscrial niul gen-
erally hranchint;. Slit-like respiratory i)oros at tho
sides of the aniliidaeral openin^js

b, Co»fnh mil' ; jinitinii/iiltir.

Otherwise resenililintj yMA/i'<(()i«».t

iaturhrachials numerous, hasals forming an inverted cup

Genliitfiral iiuil tlini/nijifiiriit l)iiitribution.

Number of known apeotes.

(0|icu flf(ures iiidicato Aincricaii ; llinsc marked ( ), Europenii )

Altucrinut,

Centrocrinu*,

I>ul<ttii'-rinu»,

Slenofriniin.
IJadrucrtnim,

1
i

i.
;-)

1
■7.

»'

FuRHATIOH.

HlLOCUHIIIJIf

Aiiiaricnii.

Ill
111

.Mi'IiH'riiiites.

DiiliiiiKriiiitcH.

a
C
5

i \

•c

"ti

•5

(.1)

(3)

1
3

a
"H.

'x
3(9)

a
X

i
1

k
S

(7)

a
•c

2
3

•c

a
'C

8
S

Ilnniiltiiii.

I'p. Ili'Morlierg.

rp. l>evon.

2
2

Eifel.

—

I(T)

i
2(3)

( triiiknny.

2
3

(«)

(6)

Ix>w. Ilplclcrlierg.

Grail wncke.

Nia);nm.

\V.Mil.H;k.
Itolieinia.
(iutlnud.

4
3

(1)
(1)

5(4)
II

(a.-i)

lluiUun Kivcr.
Trenton.

T(it!(l »|yciei 95 | JJ.

• Expliiiliiip; P./utminatusviwi P. duplicatHS, wliicli probably belong to Slariaerixui, aud P. ehia$lodiie-
/fills and i*. jii/iiiiiMut, wkicU are young spccimeus.

U...S!""!i^

2(]G

Tin: (UINOIKKA ( AMKUATA OF NOUTII AMKUK A,

luiiiin/i.t. — The' Milocriiiidii- itiul KiK'uIyptiMTiiiiilu' mo llie oi\\y mono-
cyclic faiiiilif.'^ uf tlu> Caiin'iutu wliicli liiivo ii pontiigoiial Iiuko, uiul in whicli
tlio riidialM aiu in cuntaet nil aiuund. Tliu laltor, howuvur, lU'piut from the
Mi'iociiniilu! so wiiU-ly in their ventral Hlnietiiro that tiu-ri' in no need of
further ^•onlpllri^^on. The Melocriiiidji' in many rcHpectM nlno weem di(xi'ly
related to the Ai-tiiiociiMiila', whieh I'olluwed them in time. Indeed the

CrJC-o

Flo. li MilurriHHn. Fr(i. IM. S/ertnfriniii.

(Fur ilic cxplniiatinn of the leltcM, »ec Fig. II.)

Huperficial ro.«*emhlance hetween the two families is often quite ninrkod, Imt
a Mulucrinoid is always readily distinguished from an Actinocriiioid by the
al)senre of an anal plate Itetween the nidiiils, and the consequent form of its
Ijnse, which is peuliigonal. The Melocriuidie are among the earliest known
forms of the Camerata, being already found to the extent of six species in
the Trenton group, contemporaneously with the earliest Hhodocrinidie nnil
Reteocriiiidii'. They increased in ninnlicr in the Upper Silurian, but becanu'
extinct beforr the close of tlin D'nonian. before the appearance of the Actino-
crinidiv, so lar as existing collet ('ons show. The family includes fifteen gen-
era, of which ninety-five species are known ; fifty-four from America, and
forty-one from Europe.

Some of the gcnorn referred to this family have n perfectly pentamerous
dorsal cup, the posterior intorradius being identical with the other four; but
in others there are one or more anal plates interposed between the inter-
brachiaN, by winch the pentdmerou-s symmetry i" disturbed. If this difTer-
cnce were well marked and cdnstant. it would affor 1 a basis for separation,
founded on the more or less complete ab.senoe of anal s.'ructiires from the
dorsal cup; but this being not the case, we arranged the genera only into

MKLO( UINID.K.

2C(

Miil)iliviMiuiiM witli rororcnoc to it. railing tliosc in which Noiitf triicu of mini
pIntuM i.s roiiiiil Mcidcrinitt's, mitl tlmsi! in wiiicii llivy aru «'oni|>lt>t('lyal)'-i'nt
in llio cup DolalocriuitoH. Wu liml it inipo-'^iblu to niai<(! tiif<i> (livi>ionM
fainilieH, becanxo they noi'in very intiuiuti-ly ri'latf<l in othi-r ifspfctH, and
nhadc into oacli otlior (oo I'lo.sfiy, — hiith lonnH l»t'ing poxniliiy n-prt'sonti'il
ii' -pccicH of tlu! caiiu! };t'nii!<. Thin 1^ prolialily tiiv cnMu in J/iiilnnrliiii.t ;
whili' in Alliiciiiiii.i tiiu liiNt inlt'iltracliial ol° tlic poHtfrior nidu is "iiniuwliat
larger than thu (Mjrn'-pondin;^' plate ol' the other sidcM.

Thu nainu Mclocrinidio wuh intruducud by llovinur.* it was applied hy
him, and afterwards hy Anm'lin.t ZittLd.:]; and S. A. Miik'r.^ oxdiisively to
;^onoru with loin' hasals, or tiioso that were supposed to havo four. Ith/iilif
i-rliiiiK, with live liasal"', although closely allied to MiirinrrltiU!< and Milnciiiiiin,
was referred l>y /iltel, and S. A. Miller, who subslautially adople<l Zitttd's
classification, lo the (ilyptocriiiiihi^ under wliicli thoy incliidud a variety of
genera, both monocyclic and dicyclic. In the classification of IH'.MI, Miller |{
refers to the fllyplocr' ho Ciijiii/'ifi'liiiis, (ih/jitnrrliiiis, J'/frimrrliiiis, Silihit-
rn'iiiis, and Slji/iniun —the (irst an I(dilhyocrinoid ; S!jtliiiii<iir!iiiis — a

Thysanocrinoid — ami both of these last dicyclic. This is the more curious
because Miller is the author of Siplmiiurrinux, which he described as having
three infrabasals ; while he emphatically denied the presence of infiabasals
in (!li/pt(ii'riniix ; and yet in establishing the families of the Criimidea
made the " presence oi- absence of • subrailials'" next in importance " to the
number of basals," upon whi(di his classification is principally based.

Ii ^

!•

I. MKLOCIilNITES.

SYM.MKTnY OK TIIK DORSAL Cri' HHTIIIllKIl ItV ONK Oil MOllK ANAL PLATE-S.

0LYPT0CRINU8 Ham,.

1817. 1Iai,i.; riilirmit. \,w Yciik, Vol. I., p. iso.

IS.'il. Mrrnv; Sviiii|i». Urit. i'lilii'oz Kiiss., p. .1(1

I'l.'ill. Hii.l.l.viiH; Ciiiiiiil Niiliinill^t iiikI (ic'dliiKist, Nn. 1., p. 40.

18,-)7. Hn.I,IN<i»; (iri>l. Siirv. <';iim.lii iif IS:.;) In IS.IO, p. 850.

1S50. Hll.MNOS; iliid., Dermic IV, p .1.').

lH7;t. Mkk.k ; (icdi. Siiiv. OIlio, I'liliiMMil , V.il I., p. 30.

1S7I. S. A. Mii.i Kli ; firiciii. Quurt. .loiini, Sci . p .IIS.

1S79. ZiTTKi.; llriiiilli. ilcr rnliuiihl , Vol. I., p 375.

• I,ctliini ficos-ti., IS.I.-i (AiiiK. 3), p. 82S.

f Iciiimur C'riii. Siipoiii'. p 10.

X Hiiiiill). ,l,r I'.ilir.iiilnloitii-, Viil. T., pp. 3nS-37.'>.

\ Amor I'liliiriz. Fnssils (scrmiil cilil ), p. 270.

II Ainrripaii Geolojjist, Vul. IV., pp. 275 to 280, mid pp. 310 to 357.

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268

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

1S81.
1883.
1883.

1885.
1859.

W. nnd Sp. ; Revision PaliEocr., Part II., p. 185 (Proceed. Acad. Nat. Sci. Pbila., p. 359).

W. and Sp. ; Aincr. Journ. Sci., Vol. XXV., pp. 255 to 868.

S. A. MiLLEu; Aiiier. Journ. Sci., 7ol. XXVI., pp. 105 to 113 ; and Cincin. Soc. Nat. Hist., Voi.,

VI., pp. 220 to 228.
W. nnd Sp. ; Revision Palaeocr., Part III., p. 102 (Proceed. Acad. Nat. Sci. Phila., p. 324).
S. A. Mii.LKu; North Anier. Geol. and Paloiont., p. H7.

Not Glyptoerinm D'Oubig.ny, 1852 ; Cours Element, de Pal^ort., Vol. II., p. 142, nor Prodr6me,
Vol. I., p. 47.

Not Qlgptocrhm IIai.i, 1803, Trans. Albany Inst., Vol. IV., p. 202 ; nor 28tli Rep. N. Y. State
Mus., p. Vii:=:Manarri>iui.

Not Gtyptocrinm Hall, 1872; 24tli Rep. N. Y. State Cab. Nat. Hist., p. 206 = Seteocrinus.

Not Glyptocnnm IIall, 1872; ibid., p. iOT := Pti/cho<riiiui.

Not Glyplocrinm Wetherbt ; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 83 = Reteocrinut.

Not Oli/ptocriniis S. A. Miller; ibid.. Vol IV., p. 74 = Compsoeriniis, nor p. 75 ^ Reteoerinus,

Not Glyplocrinus Etiieridge and Nicholson, 18S0, Siliir. I'oss. of Girvan Distr., p. 328.
Syn. Fosnil Enrriiii/e AmiiOTUt, 1838; Anier. Journ. Sci., Vol. XXXV., p. 405.
Syn. Icosidactylocrinitei Owen, 1843 (Catalogue name).
Syn. PycHOcrinus 8. A. Miller; Journ. Cincin. Soc. Nat. Hist., Vol. A'l., p. 231.

Calyx obconical or subglobose; plates thin, often highly ornamented; the
fixed brachials pa.ssing imperceptibly into arm plates, and the interbrachials
into disk plates ; the arms rising vertically from the edge of the tegmen.

Basals five, of uniform size, forming a small cup. Badials and costals of
nearly equal size ; the second costil hexagonal. Distichals varying in num-
ber, there being but two in species in which palmars take part in the calyx ;
but when the second bifurcation takes place in the free arms, they are quite
numerous, frequently six to eight or more in the calyx, followed by several
others in the free arms. When this is the case, the second distichal gives
off a large pinnule ; while in the other the proximal pinnule is developed
into an arm. Arms rarely branching beyond the second b'furcation, rising
vertically from the calyx; they are long, slender, roimded on the back,
and composed of a single series of short, slightly wedge-shaped pieces,
which do not interlock. Pinnules slender, closely arranged ; the proximal
ones the stoutest, and frequently incorporated into the calyx.

Interbrachials definitely arranged ; the first large, resting upon the slop-
ing upper faces of the radials ; there being two plates in the second row, and
two, sometimes three, in the higher ones. The anal side wide.st, having
generally three plates in the second and all succeeding rows. Interdistichal
spaces large, composed of numerous small plates ; some species also have
interpalmars. Ventral disk depressed-hemispherical, very slightly extend-
ing above the level of the arm bases; the ambulacra subtegminal, except
near the periphery, where some of the small covering pieces are exposed,
but the course of the ambulacra is indicated by surface ridges. Flates
of the di,sk very minute and irregularly arranged, decreasing in size toward

fr I

MELOCRINIDiE. 269

the arms. The arrangement of the larger plates at the summit is also irreg-
ular, being unlike that of oi'als, which probably are not rqjresented. Anal
opening excentric, at the summit of a small protuberance. Column round;
axial canal large, pentalobate, die lobes directed interradially, except in one
species in which the stem is pentangular and the cential canal radialhy
disposed.

Distribution. — Glf/ptocrinus, as now amended, is confined to the Trenton
and Hudson River groups, and probiibly is restricted to America.

Ti/pe of the genus. — Oli/ptocnims decadactyhis.

Bemarks. — The genus agrees in the uniserial arms and its general
structure with Mariucrimis, but that has four basals instead of five. It
resembles Compsocriutis, whicli has also four basals, but an anal plate in
line with the radials, which throws it into the Batocrinida).

The European species referred to Glyptocrinus, with the possible excep-
tion of G. basilis, belong to other genera. The specimens described under
the name Glyptociimis ylubularis by Nicholson and Etheridge probably belong
to Archwocrinus. They evidently had infrabasals, for the intcrradials rest
upon the basals, ar.d they probably had biserial arms.

The following species either are synonyms, undeterminable, or are
removed from Gli/ptocriims to other genera:

Glyptocrinus parvus Hall, Teterted to Ptychocrinus.

" any!(/rt>*is Miller and DvEB, synonym of .... IHychocrinus parvus.

" j/mciVis Wktherbv, synonym of Ptychocrinus pamts.

" Harrisi Miller, referred to Compsocrinus.

" Carleyi Hall, " Mariacrinus.

" miamiensis SIiller, " Compsocrhms.

" Baeri Meek, " Xenocrinus.

" expansus Phillips, " Sagenocrimts.

•' armosus McCiiesney, " Siphonocrinus.

" siphonatus Hall, synonym of Siphonocrinus annosiis.

" nobilis Hall, referred to Siphonocrinus.

" eoqnatus Miller, synomym of Reteocrinus Onealli.

" O'NealU (Nealli) Hall, " Reteon-inus.

" lacunosus lUhhinGS, " Archceocrintts.

" subnodosus Walcott, " ........ Rhaphanocritius.

" sculptus Miller, " Rhaphanocrinus.

" argutits Walcott, " Stelidiocrinus.

" priscns Billings, " ........ Periglyptocrinus.

" fimbriatits Shumard, undeterminable.

" libanus Safford, not defined.

" plumosus Hall, detached column and arms.

" quinqueparlitus Billings, detached column and arms.

" Pattersoni Miller, undeterminable.

i.'

n-.-i -

III:!' ■

iHi:

Hir

270

THE CRINOIDEA CAMERATA OF KOUTII AMERICA.

Olyptocrinus deoadaotylus iiali,.
PMe XX. Figs. 4a-e and Plule XXI. Fiijs. 4a, b.

1G47. Hali,; I'ahconl. X. Y., Vol. I., p. 2S1, Piute 77, FiRa. l«-/'iiml I'late 78, Figs. l«-«.

1873. MiiEK;'Pala'()iit, Oliio, Vol. I., p. 30, Plate 2, Figs. U, b.

1879. Ziftel ; llaiiilb. d. Palieont., Vol. I., p. 375, Fig. 202.

1881. W. and Sp. ; Kevisioii Pateocr., Part II., p. ISS (Proceed. Acad. Nat. Sci. Pliila., p. 362).

1883. S. A. Miller; Jouru. Ciiiciii. Soc. Nat. Hist., Vol. VI., )). 220, Plate 11, Fig. 1.

Calyx obconical, somewhat higher than wide ; the interratlial and iiiter-
distichal .spaces a little flattened, giving a cross-section pentagonal through
the costals and decagonal through the distichals. Surface beautifully orna-
mented with radiating angular ridges ; those following the rays to tlie arms
a little the largest and most prominent. Other ridges pass sideways from
tlie centre of the plates, meeting with similar ridges from the interbrachials,
which divide the surface into numerous triangular impressed areas.

Basals small, their width at the top greater than the height. Eadials
heptagonal, larger than the basals, and as wide as long. First costals a little
smaller than the radials, and hexagonal ; the .second as large as the fir.'<t, but
angular above. Distichals two, comparatively large. Arms twenty, simple,
rather stout, cylindrical. The four lower plates, which in large ^'peciInens
are incorporated into the calyx, are elongate, but decrease in length upward ;
their upper and lower faces being parallel, the succeeding free plates .slightly
cuneate. Pinnules long, closely arranged ; the proximal ones given off from
the third palmars, there being none from the distichals. Interbrachials
numerous, gradually decreasing in size; arranged in ten to twelve ranges:
1, 2, 2, 2, dc, at the regular sides, sometimes with three plates in the second
row. Anal side having three plates in the second and succeeding rows; the
l)lates of the median series longitudinally arranged, and covered by a ver-
tical ridge similar to the ridges along the rays. Interdistichals in four to five
rows, the interpalmars in three ; the former arranged : 1, 2, 2, 2, 2 ; the
latter placed in a single longitudintvl row. Ventral disk slightly convex,
composed of irregular pieces with a small prominence in the centre. The
plates are smtill, and gradually decrease in size outward, those along the
margin being quite minute, and enclose some of the " SuumiMiltchcn." The
latter, which are also frequently preserved upon the arms and pinnules, con-
sist of two very small irregular rows of pieces. Anus subccntral, at the
iqiper end of a protuberance. Column round, of moderate size, the nodal
joints a little the widest ; axial canal rather large and pentalobate.

.:7

MELOCRINID.i:.

271

Ilumon and Locality. — Hudson River yroiip ; Cincinnati, 0. ; Wayncs-
ville, 0., and MayHville, Ky.

Itcmurks. — It lias been supposed by several writers that G. (Iccaduch/hix
had rudimentary infrabasals, but this is not the case. In a fine specimen
from which every vestige of the stem was removed, we could follow the
interbusal sutures to the axial canal, and found the latte; to be interradial
and not radial, the part which had been supposed to represent tlie infra-
basals being the upper stem joint.

Qlyptoorinus Dyeri Meek.
Plate XX. Figs, la, h, c ; ami Plate XXI. Fi'ffs. 3a, b, c, and Fig. 6.

1872. Meek ; Proceed. Acnd. Nat. Sci. Pliila , p. 3U.

1873. Mekk; Geol. Rep. Ohio, I'alicont., Vol. I., p. 32, Plate 2, Figs. 2rt, i (not 2c)-
1881. W. and Sp. ; Revision Palieocr. ; Part II., p. 188.

1883. S. A. Miller; Jonrn. Oincln. Soc. Nat. Hist., p. 222.

Sjn. G/^plocriiiiin l)j/eri vur. sithylohomis — Meek; 1872, Proceed. Acad. Nat. Sci. Pliila., p. 310;

also Geol. Rep. Ohio, Pala'ont., Vol. I., p. 34, Plate 2, Fig. ic.
Syn. Glj/ptocrinm subglohonus — W. and Sp. ; 1881, Revision Palwocr., Part II., p. 189.
Syn. Glyptocrinm Rkhardsoni — Wetiierii\ ; 18S0, .Toiirn. Cincin. Soc. Nat. Hist., Vol. II., p. 21.5,

Plate 16, Figs. 1 and Iff.
Syn. Ri'leocriimn Richardsoiii — \V. and Sp. ; Revision Palieocr., Part II., p. 193.

Of the type of Ghjptocrhws decadactyhts, but the Ciilyx globose instead of
obconical. It has a similar ornamentation, but the ridges are le.«s angular,
being rounded, and those following the radial and anal plates are more
prominent ; the arms are thinner, and the second bifurcation takes place in
the arms.

Basals small, much wider than long, with a sharp, almost circular rim
around the bottom, which extends slightly beyond the column. Eadials and
costals a little wider than long, the latter somewhat the smallest. Distichals
nine to sixteen or more, their number varying among the rays, the five to
eight lower ones forming part of the calyx, the others being arm plates.
The two lower distichals nearly as large as the upper co.'.tals. The succeed-
ing plates decrease rapidly in size upwards. Their second plate has the
form of an axillary, giving off to the outer side of the ray a large pinnule ;
the third is quadrangular and bears no pinnule ; the fourth plate bears the
second pinnule at the inner side of the ray, above which every plate is
pinnule-bearing. In large specimens, as much as six pinnules are incorpo-
rated into the calyx, and these are not only larger than the succeeding ones,
but are placed farther apart. The apposed fixces of the distichals, and appar-

■

> h

■■?

272

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

eiitly of all arm plates, are covered with well marked radiating striae and
grooves. The arms in their free state branch but once ; they are rather thin,
especially at the upper ends, and composed of short, somewhat cuneate
pieces. Interradial spaces slightly impressed between the costals, and dis-
tinctly grooved between the distichals. First interbrachials about as large
as the radials; the plates of the second row a little smaller, supporting
a fourth plate b itween their upper sloping laces, and two plates in the next
two rows, followed by numerous small pieces, which enclose the fixed pin-
nules. The anal area is a little wider, having three plates in the second and
all succeeding rows up to the first pinnule; the middle series being marked
by a rather conspicuous ridge. Interdistichal spaces elongate, their median
portions deeply grooved ; the first plate large, followed by two plates in the
second row, and a number of small pieces above. Construction of the ventral
disk, and position of the anus unknown. Column round, — not indistinctly
pentangular as stated by Meek ; the nodal joints somewhat larger ; the axial
canal pentalobate, and moderately large.

Horizon and Locality. — Hudson River group ; at Cincinnati, Lebanon and
Waynesville, Ohio, and also found at Richmond, Ind.

I'l/pe in the Museum of Comparative Zoology, Cambridge.

Bcmurks. — This species is readily distinguished from G. decachdyhs, its
nearest ally, by the uninterrupted series of anal plates. It is quite remark-
able for its large number of incorporated pinnules, of which the proximal
one.s have almost the proportions of armlets. Meek's G. Di/eri, var. yloboms.
which we thought to be a good species, judging from the figures, can hardly
rank even as a variety. We have examined the type in the Museum of
Comparative Zoology, and find it to have all the characteristics of G. Dyeri.
Wetherby's G. Richardsoui also, which we once regarded as a lieteommw, is
based upon a somewhat aberrant specimen of this species.

(?^ Olyptocrinus Shafferi Miller.
Plate XXI. Figs. 3d, e,f.

1875. GI)ptocr!nui Sinferi — S. A. MiLimi; Ciiicin. QiinrtorljT Journ. Sci., Vol. IT., p. 277; and 18S0,
Jouni. Ciiicin. Soc. Nat. Ilist., A'^ol. III., p. SSS, Plate 7, Figs. 2fl, i, and 3», 4, c.

1881. Glyptocrinus Shafferi — Vf. and Sp. ; Revision PnliEOcr., Tart 11., p. 189.

1883. Pj/cnocrinus Shafferi— ?i. A. Miu.kk ; Joiirn. Cincin. Soc. Nat. Hist., Vol. VI., p. 231, and North
Amer. Geol. and Palaiont., p. 276.

There is but little doubt that the small specimens which S. A. Miller
described as Ghjptocfinus Shafferi, and G. Shafferi, var. germanus, and for

r'li

MELOCRIMD.i:.

273

which he afterwards proposed the genus Pf/ciiocrimm, nro young examples of
Gl>/ptocrinus Dtjiri The specimens liave vnriou.sly from nine to twelve dis-
tichals, but in place of having six to eight of them incorporated into the'
calyx, only one or two are calyx plates, the others being free. That the
specimens are comparatively smaller, the column stouter, the basals propor-
tionately larger, the interbrachials and interdistichals less numerous, the
arm joints higher, the pinnules stronger and placed farther apart, all indicate
a less mature stage of individual growth, n jihase through which every
Gljptoerinus must naturally have passed.

Miller defines Pi/cnocrimis as follows : " Calyx cup-shaped. Column
round. Basals five, small, pentagonal. Trimary radials 3x5. Sec-
ondary radials none. Regular interradials three. Arms ten, but some-
times dividing after becoming free. Pinnules dense and strong." This
description would apply equally well to any young Gli/ptocrimiK. It must be
remarked, however, that both of Miller's types have small interdistichals,
which he overlooked. The presence of these plates proves conclusively that
at least one of the distichals takes part in the calyx, and that " secondary
radials" are not unrepresented in those specimens, as Miller supposed.

Iforuon and LocalHy. — Found associated with the two preceding species
at Cincinnati and other places.

T//pe in the collection of S. A. Miller.

■

i'i

1 1 1

li '■■

■'\

OlyptOCrinuS ramuIoSUS Billings.
Plate XX. Figs. Ga, h.

1856. E. BliLiNGs; Qniiadian Naturalist and Geologist, No. 1, p. 54; also Geol. Surv. of Canada (Rep. of

Progress), 1857, p, 258, and 1859, Decade IV., p. 57, Plate 7, Fig. 2ff and Plate 8, Fig. 1.
1881. W. and Si'. ; Revision Pnteocr., Part II., p. 189.
1883. S. A. MiLLKii ; Jouru. Cinein. Soc., Nat. Hist., p. 221.

A large species. Dorsal cup obconical, somewhat rounded at the base.
Costals and distichals remarkably nniform in size ; also the palmars propor-
tionally large. Plates almost flat and without any markings, except a con-
spicuous, obtusely angular ridge passing up the rays, occupying nearly one
half their width.

Basals small, only the upper angles visible from a side view. Radials
somewhat larger than the costals, as long as wide. Distichals six, exception-
ally seven ; the proximal one as long as the costals, but a little narrower;
the succeeding ones smaller. There are fixed pinnules from the second,

n''

frin

07 •

THE C'lUNOIDKA CAMKRATA OF NOIITII AMERICA.

foiutli and fifth plates (none from tlio tliird), which arc long, but not ns
conspicuous ns in the preceding species, and they grow more obscure with
age. All brachials of the third order are free ; the two or three lower ones
are longer and have parallel upper and lower faces ; the others being short
and cuneiform. The arms, which branch once, are long, very slender,
rounded on the back, and provided with rather long pinnules. Interbrnchial
plates large, to the fifth row nearly of equal size, and as large as the second
distichals ; arranged : 1, 2, 2, 2, 2. From the sixth row, where the pinnules
come in contact with the intcrbrachials, the arrangement is less regular, and
the plates gradually grow smaller. There seems to be no anal ridge, but the
posterior interradius has three plates in the third row, and frequently in the
second. The interdistichal spaces are remarkable for theii great length, and
the large size of the plates ; they are arranged : 1, 1, 2, 2, 3. Construction
of ventral disk, and position of anal opening unknown. Column round,
cojnposed of short, sharply edged joints.

HiirizoH ami LncuVilij. — Trenton limestone ; Ottawa, Canada.

Types in the Canada Survey Museum,

Olyptoorinus ornatus Billinos.

Plate XX. Figs. Ga, h.

1857-

BiiiTNOs ; Geol. Surv. of Cnnndn (Rep. of Progress), p. 260 j also 1859, ibid., Decade IV., p. CO,
Plate 9, Figs. 2rt, A.
1881. W. mid Sp. ; Kevisioii Pnlxocr., Part IT., p. 189.
1883. S. A. Miller; Jourii. Ciiioin. Soc. Nat. Hist., Vol. VI., p. 225.

Of the type of Ghjptocrimis Dyeri, but readily distinguished by its orna-
mentation, the smaller number of interbrachial and anal plates, and by
having ten arms instead of twenty. Calyx globo.se, the plates delicate, orna-
mented with five or six rather conspicuous, finely striated ridges, radiating
from the centre of the plates. The ridges passing up the radial and anal
plates are more prominent and broader than the others ; those from the
intcrbrachials, which are not confluent with the ridges of adjoining plates,
forming a well defined star upon each plate.

Base short, with a projecting rim and a shallow depression at the bottom.
Radials and costals a little wider th.an long, the radials one third the largest.
Four of the distichals generally take part in the calyx, of which the two
proximal ones are nearly as large as the upper costal, the second pinnule-
bearing ; the two succeeding ones are much smaller, but yet twice as large

MKLOCRIN'IO.i;.

275

as the free bmcliiiiis. Arms ten, Hlendor, not bifurciitinj^; coini)0-e<l of qimd-
nuigiilar, luoilcrately liiyh joints with long pinnules. Interbrnehiiils; 1, 2, 2,
2, decreasing in size upwards. The anal interradins consideiably wider:
1, 3, 3, c/c. ; the middle series longitudinally arranged, and marked by a
conspicuous ridge. Interdisticlmls : 1, 2, <./(;. Construction of ventral disk
and anus uidcnown. Column obscurely pentagonal to judge from the top
joint ; the axial canal of medium size.*

Horizon and Lnml'iti). — Trenton limestone; Ottawa, Canada. -— —

Types in the Canada Survey Museum at Ottawa.

Glyptoorinus marginatus Billin-gs.
Plata XX. Fig. 2.

1850. Glyplorriiim marginatus — Y.. BiiiiNOs; Gcol. Siirv. Caiimlii (Ucp. of Progress), p. SCOj also 1859,

Dc'cndo IV., p. 59, Piute 9, Fig. \a.

1851. Atchroci-iiim murginatm — VV. and Sp. ; llcvisioii Pulneocr., Part II., p. 190.
1859. JrchtEocrinus marginatus — S. A. Mar.Ea; N. Ainer. Guol. mul Palitoiit., p. 225.

A large and well marked species. E.vact form of calyx undeterminaltle
— the only specimen being in a crushed condition — but probably subglo-
bose. Plates evenly margined by a strong elevated border crossing the
radial ridges, their middle portions smooth and very thin; the inner floor of
the plates marked by slender conspicuous tubercles. Radial ridges not very
prominent, wide and flattened.

Basals small, projecting laterally. Radials and costals as long or a little
longer than wide ; the former twice as large as the costals. Distichals about
seven ; all, or nearly all, incorporated into the calyx, rapidly decreasing in
size; the proximal one as large as the costals, and of similar form; the upper
axillary, and succeeded by free arm plates. Arms delicate, composed near
the calyx of moderately long (nearly as long as wide), slightly cuneate
joints. There are apparently no fixed pinnules ; the free pinnules long, stout
at the base, distinct';, '..pering. Interbrachials: 1, 2, 2, 1, 2, 3, 2, followed
by others ; their five lo, or ones of nearly the same size as the radials. Anal
area considerably wider, and compo.sed of a much greater number of plates
than in any other species of the genus. It contains a middle series of anal
plates, marked by an obscure ridge, and to both sides of this ridge there are
numerous interbrachials, arranged like those of the four regular sides, but

• It is doubtful if the detached column, which Billings found associated with the type specimen, belongs
to this species.

: ^

27G

TIIK CUINOIDKA CAMKRATA OF NOUTII AMKKICA.

tho pliitt'H Momcwliat Hiiiullcr. Notliiiig in known of the ventnil disk, tlio
aniil opening, ami tlie upper portions of tho arniM. Column Mtrony, roinul ;
composed oi'ultenuite thick mid thin joints, all rounded along tlio edges, the
former twice as high na the latter, and somewhat wider. Arial canal large,
pcntalohato.

Il'irizon ami Lomlilj. — Trenton liinostono ; City of Ottawa, Canada.

Itiinaihs, — Tliis species has a superficial resemblance to certain species
of Arc/neocriiiiia, and in 18S1 wc referred it to that genus. But on examin-
ing tho type specimen from tho Canada Survey Museum we find it has no
iufrabasals, and the angles of the axial canal are interradially disposed.

(?) Olyptocrinus Fornshelli s. A. Miller.
Plate XX. Firf. 3, and Plate XXI. Fig. 5,

1871. S. A. Mlu.ER; Ciiioiii.Qimrl. Joum. Soi., p. 348.
1881. W. mid Sp. ; lU-visiou I'lila'ocr., I'nrt II., p. 188.

1883. 8. A. MiLLKii; Jciuiii. Ciuciii. Sue. Nut. Hist., Vol. VI., p. 227j and Nortli Amcr. Gcol. and Palte-
oiit., p. 248.

Calyx elongate, obconical ; dorsal cup almost twice as high as wide, its
sides convex. Plates delicate and beautifully ornamented, being traversed
by sets of from five to seven small ridges, a set directed to each side of
the plate, and each set continued upon adjoining plates. The ridges of the
same set are parallel, those of different sets meeting at an angle at the
middle of the plates, and being so arranged as to form numerous rhombs,
each containing two sets of included triangles. Upon tho radiols and costals
tlie median ridge is but slightly stronger than the others, but on approach-
ing the distichals it enlarges rapidly, and at the fifth plate it attains the
proportions of an arm.

Basals small, forming a .short cup; the interbasal sutures deeply notched.
Radials and costals longer than wide, their upper and lower faces unusually
narrow ; the first costal somewhat longer than the radials, the second a little
smaller generally. Of the distichals, the ten to twelve lower plates take
part in the calyx ; the three proximal ones being but third smaller than
the costals; the fourth is considerably shorter, and the succeeding ones
almost as short as the free brachials. Arms bifurcating (once or oftener),
long, very slender at their tips ; constructed of moderately short, cuneate
pieces with stout and long pinnules. Interradial and interdistichal areas
elongate, and composed of an unusually large number of pieces ; the former

T
1

MKLOCUINID^E.

277

arrangcti in ono uf tlio fpcciinouH: 1, 2, 3, 3, 3, 3, 3, 3, i, l ; the Iiittor:
1, 2, 3, 3, 3, etc. Tlic luiiil side contuinH three plates in the necond row, and
tliero arc otiier extra plates above. Nothing is known of the veutrul disk or
anal opening. Column Hhar|dy pentangular ; the nodal joints the longCMt, their
ec1ge.s (lattencd (not eonvex) ; internodal joints short and angular in tho
upper part of the stem, but gradually growing as large as tho nodal ones ;
axial canal wide and slightly penfaloltate, tho lobes disposed radially, in tho
same direction as the outer angles of the stem.

Jloruon and Locali/i/. — Upper part of tho Hudson IJiver group; at Mor-
row and Waynesvilie, 0.

Ty/>es in tho collection of Mr. F. L. Fornslicll.

ItetHiirks. — It is with sonio hesitation that we place this species iinder
Gli/iitocnnm. It differs from all other species of the genus in the pentangular
stem, and tho radial position of its axial canal, a feature in which it is at
variance with all other known monocyclic Palteocrinoids. That it actually
has no infral)asals, we ascertained from a fragmentary specimen by exposing
the inner floor of the basal cup. It has in the centre a large pentangular
open space, whose angles are pointed to the interbasal sutures, taking the
same direction as the angles of the stem. A somewhat similar departure
from the rule is clain)cd to exist in tlie recent genus Pcntacrinns, in which,
however, stem and canal are Hito-radial.

!JI

FBRIGLYFTOCRINUS W. and Sp. (nov. gen.).

Closely allied to GJi/ptocrinus, but having larger basals and well developed
biserial arms ; the arms of Gl>/ptocnnus being described by all writers as uni-
serial. The only two species known to us are our new species Perifffypto'
crinus BilUiigsi, which we make the type of that genus, and P. jiriscus, which
was described by E. Billings as a Gtyptoctimis, Fragments of a third species
are found in Alexander County, Ills.

Distrihiiioii. — Black River shale, and Trenton limestone of Canada.

' 1

.^P \^

( :

li f

Feriglyptoorinus Billingsi w. and Sp. (nov. sp.).

Plate XXI. Figs, la, b.

A beautiful and highly ornamented species. Dorsal cup elongate-obcon-
ical, higher than wide, somewhat depressed at the interradial and interdis-

11.

278

THK CULNUIDEA CAMEUATA OF NOHTH AMKItlCA.

(ieliiil "piicesi. Tho plates niarkt'd by roundutl liilgc-*, ono to oacli Ma of tlio
pliitos; tlioHU iipuii tliu nuliiils and lixud bnicliiul.<4 iiiiicli wider and mure
pruiiiineiit. The ridges tapering tu the inarginrt ot' the [iliituH, hu an tu form
bead-like clevatiouH along the rays, nnd a well defined Htar upon each Inter-
brachiul.

Dasids largo, forming an elongate cup, which is dreidy grooved at the
interl)asal Miitures, and the wideM of tho jjlatcH are bordered by conspieuoii.s
ridges, which aro prolonged to tho upper part of the radials. lladials and
costals largo, longer than wide; tho radials larger than the costals. Dis-
tichals two. Pahnara frco from tho fourth plate. Arnis twenty, simple,
long, slender, gradually tapering to their tips, and beyond tho fourth or fifth
plate strictly bisorial. The first pinnule is given oil" from tho second pal-
uiars, and all succeeding brachials arc pinnule-bearing. Intorbrachials : 1, 2,
2, 2, 2, c/c; the lower ono considerably tho larger. Interdistichals: 1, 1, 1 ;
intorpalinars : 2 to 3. Anal interradius tho widest, the lower plates nome-
Avhat larger than the corresponding plate of the four other sides. It con-
tains three idates in the second and all succeeding rows, tho middle s('rio.<»
marked by n somewhat interrupted longitudinal ridge. Similar but shorter
ridges proceed from tho first anal pluto to adjacent radials. Construction of
ventral disk, and position of anus not known. Column slightly decreasing
in size downward; round; composed of rather long joints with convex
edges ; the nodal joint.s considerably thickest. At three inches from the
calyx, each internode contains seven to eight joints, of which every second
or third is nearly as largo as tho nodal ones.

Iliir'izon and LncaVdy. — Trenton limestone, Ottawa, Canada.

7//y/c.s in the Canada Survey Museum at Ottawa ; collected by Mr. John
Stewart.

We take pleasure in dedicating this elegant species, the type of a new
genus, to our friend Mr. Walter R. Billing-i, the author of several important
papers on Crinoids, to whom we are indebted for many favora.

Periglyptoorinus piisous (Bulixos).
Pkde XXL Fig. 2.

1856. Oli/plocrimiii prisem — Y,. BiLLrens; Cool, Surv. Cnnndn (Rep. of Progress), p. 287; also 1859, De-

ciule IV. p. 5(1, I'late 7, Figs. \a, h, e.
19S1. Gli/plocriniis prisnia — VV. and Sp. ; Kovision Pnlwocr., PnrI IT., p, 189.
1S83. (!li/ploeriiiu» pmcm — S. A. Millkb; Joiirii. Ciiicin. Soc. Nat. llisl., p. 225.
1883. (?) Archteocrinm priscui — W. aud Sp.j llcvision Palieocr., Part III., p. 301.

MKr.OCHINID.K.

27tt

■

A Biiiall upccicH. Doi'Mal cup ohconiciil with uli^^'litly convex HidcM ;
Ncction iicrosM tlio co^tiils Nliiirply puiitii^oiial, owing to tlie t'on.H|)icnoiiM radial
rltlgoH, which paMH from Uio urnm down to tlio cuntro of tliu raUialn, wluro
they divide and are continued to the l)aMalH. The ridgcH, which arc rounded,
grow narrower toward the middle of tiie pliitcM, widening at their nuirgius,
Surface, e,\ce[)t along the ridgen, covered with nuineroun Hnu\ll pUHtuliM
without definite arrangement.

DasaU large, forming a pentagonal cup with a rim around the bottom.
Railialn twice or nearly three tinicM as largo oh the second costals ; the t'lvnt
costal linger than the Hoeo'id. Dintichals free beyond tiie foifth plato ; the
first and Hccond couMiderahly the larger; the necond one pinnule-hearing,
and also the fourth (not the third), which in ulightly wedge-Hhaped, and con-
sidorably smaller than the preceding ones; from the fifth to the eighth, the
platen arc decidedly cuneato, the higher ones interlocking. Arms 10, simple
throughout ; thin, composed of two series of trigonal pieces. Interbrachials :
1, 2, 2, civ.; the plates large. Anal side slightly wider; the first plato
a little larger than the corresponding ones of the other sides ; the succeed-
ing pieces comparatively smaller ; there are three plates in the second row,
and In all the rows above. The plates of the median series are formed into
II conspicuous longitudinal ridge, -i 'lich divides on the first nnal plate, send-
ing a branch to the middle of adjacent radials. Nothing is known of tho
structure of tho ventral disk and anal oi)ening, and nothing definitely of the
column.

Horizon ami LocalUt/. — Black River limestone ; Renfrew Co., Canada. • —

Tijpe in the Canada Survey Museum at Ottawa.

Remarks. — Tho large columns which E. Billings figures from the Tren-
ton group of Ottawa, and which he thought might be referable to O. primm,
probably belong to a different species.

STELIDIOCRINUS An.ieli.v (Restricted by W. and Sp.).

1878. AMOELtN; Iconngr. Crinoiil. Siioc, p, 21.

1879. ZiTTEL; HiukII). der I'ulicoiit., Vol. I,, p. 345.

1881. W. mid Sp. ; Ucvisimi Piilreocr , Part II., p. 98 (Proceed. Acnd. Nnt. Sci. Pliilii., p. 272).
1885. W. mid Sp. ; ibid., Part III., p. 102 (Proeccd. p. 324).

Calyx small, subturbinate, plates smooth ; interrndial .ireas depressed ;
radial plates elevated but not ridged; ventral disk composed of but few
plates.

|T!!V

280

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Basals five, forming an acute-angled pentagon. Radials large, wider
than long; lunate. Costals two; the first quadrangular; the second much
larger, almost as large as the radials. Distichals 2 X 10 in the calyx, the
others free arm plates. Arms ten, simple, uniserial, rather stout; pinnules
strong. Interbrachials : 1, 2, 1 ; the first very large, rising to the top of the
first costals. Anal area wider, containing three plates in the second and
third rows, and smaller ones above. Anus excentric, represented by a simple
opening, which faces laterally. Ventral disk low, the orals very large, occu-
pying in *S'. capitulum fully three fourths of the whole surface. Column
round.

Distribution. — Hitherto found only in the Upper Silurian of Gotland,
Sweden, but we now refer to this genus Walcott's Gli/ptocrinm arguUts from
the Trenton limestone of New York, with some doubt.

Remarks. — Angelin's descriptions and figures are so confusing that no
uniform generic characters can be deduced therefrom, unless some are elimi-
nated. Taking the first species S. cajjUiilum, Tconogr. Plate XVII., Figs.
5-5(7, ^^^^ ^h® ^^^'^^ figures of his second species S. laevis, ibid., Plate XV.,
Fig. 20, we have the type indicated by the above descriptions; but Plate
XXVIII., Figs, la, 1), figured also as S. laevis, is clearly a DcsmiJocrinus, and
the specimen represented on Plate XXXII., Figs. 3 and 3«, is probably incor-
rectly figured, either as to the anal side or the arms. Plate XIX., Fig. 6,
figured as S. oralis, is a totally different thing, and probably belongs to the
Rhodocrinidaj. Plate XXI., Figs. G, 7, described by Angelin as Ilarmocrinus,
and fonsidered by us (Revision, II., p. 99) as belonging to Stelidiocrimis, has
very possibly a dicyclic base, and strongly resembles Tlii/sanocrimis. We have
not the material to settle these questions, but by restricting the genus to the
above mentioned forms, we have something tangible. The genus, as thus
defined, differs widely from any other of this group, especially in the struc-
ture of the disk, which is quite remarkable. The quadrangular first costal
distinguishes it from the associated genera with five basals.

(?) Stelidiocrinus argutus (Walcott).
Plate XXIV. Fig. G.

1883. Oli/ptocrinut argulus — Walcott ; 35lh Rep. N. Y. Slate JIus. Nat. Hist., Plate 17, Fig. 9.
1835. 0) Stelidiocrinus arpatiis — W. and Sp. ; Revision ralicocr., Part II., p. 102.

Calyx small, somewhat pentangular; the interradial spaces depressed.
Basals five, rather large. Radials subquadrangular, the upper faces moder-

MELOCRIMDiE.

281

ately concave ; their upper corners but slightly truncated. First costals
quadrangular, not more than half the size of the radials, a little wider than
long, the lower face convex. Second costals nearly as large as the radials,
their upper faces forming an obtuse angle. Distichals one in the calyx.
Arms two to the ray ; composed of rather stout quadrangular pieces. The
two or three proximal free plates about as long as wide, the others compara-
tively longer, and increasing in length upward. The pinnules, which are very
stout, almost take the form of arndets; they are placed far apart, and their
joints, like those of the arms, grow longer upwards. Interbrachials three
preserved in the specimen, but having others above ; the arrangement of the
plates at the anal side unknown. Column of medium size; the joints
rounded at their edges, and decreasing in height downward.

Ilorkon and Locality. — Upper part of Trenton limestone; Trenton
Falls, N. Y.

Tz/pe in the Museum of Comparative Zoology, Cambridge.

Remarks. — We refer this species with some doubt to StcUdiomnus, which
it approaches in its general characters ; but as nothing is known of the struc-
ture of its anal side, it may belong to a different genus, and perhaps to
the Dolatocrinites.

1 I

MARIACRINUS Hall (emended W. and Sp.).

1859. Hall (in part) ; Palicont. N. Y., Vol, TIL, p. 104,

1881. W. mid Sp. ; llevisioii Paltcocr., Part II., p. Ill (Proceed. Aend. Nat. Sci., Pliila., p. 2SS).

1385. W. and Sp. ; Revision Pateocr,, Part III., p. 104 (Proceed. Acad. Nat. Sci,, Pliila., p. 320).

1889. S. A. Millkr; N. Aiiicr. Gcol. and Palroont., p. 259.

Calyx obconical, in general aspect resembling Gli/ptocnnns ; intcrradial
and interdistichal spaces large and more or less depressed ; the posterior
interradius distinguished by having three plates in the second row; the
plates of the rays marked by a strong longitudinal ridge.

Basals four, small, almost of uniform size. The one facing the anterior
side a little the largest and pentangular, the others irregularly quadrangular.
Radials and costals of similar size; costals two, the first hexagonal. Dis-
tichals two to four. The palmars, of which generally the proximal plate
only takes part in the calyx, support the arms. Arms composed of
cuneifo.-m pieces, which either remain simple, or give off a few branches
to one side. Pinnules given off from opposite sides. Interbrachials rather
numerous; anal side a little wider, and containing additional plates. Ventral

282

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

disk flat; composed, so far as observed, of very minute, irregular pieces,
apparently without oral plates. Anus excentric, opening out directly through
the tegnien. Column round ; axial canal of medium size, and obtusely pent-
angular.

Dldribution. — Upper Silurian of Amerisa, England, and Sweden.

Remarks. — Ilall in proposing this genus made " Mariacrinus " mhilissimus
the type of a genus, which in all essential characters agrees with Mclocrinm
Goldf., notably in the arm structure ; the arms being given olf from the
sides of tubular appendages. Among the species referred by Hall to Maria-
crinus were some with a very different arm structure, and in 1881 we recon-
structed the genus with Mariacrinus plumostis and M. Carkyi as types. The
genus, as we proposed it, includes only those species with four basals in
which the arms are given off directly from the calyx.

Zittel regards Mariacriiim, as typified by M. nobilissimus, as a synonym of
Ctcmcriiius Bronn, in which we agree ; but the latter genus, according to
Sehultze, * is identical with Melocrinus.

Mariacrinus macropetalus Hall is probably a Cori/mhocrinus Angelin ; Maria-
crinus stuloniferus Hall is described from fragmentary columns. GI>/piocrinus
Ilarrisi S. A. Miller, which we erroneously referred to Mariacrinus, not
knowing it Imd an anal plate between the radials, has been transferred to
Compsocrinus. Mariacrinus granulosus S. A. Miller is too fragmentary for
identification, but certainly belongs to a very different group.

Mariacrinus Carleyi (Kali,).
Plate XXII. Figs. Sa, h, c.

1863. Gli/ptoerimis C<7%i — TUti, ; Trans. AUinny Inst., Vol. IV., p. 203; also 28th Rep. N Y. State

Mu9. Nat. Hist., 1375, p. 132, Plate 14, Figs- 7-10.
1881. Glyptocrinus Carleyi — IIall; 11th Ann. Geol. Rep. Indiana, p. 261, Plate 13, Figs. 7 to 11, and

Plate 15, Fig. 6.
1881. Mariacrinus Carleyi — W. and Sp. ; Revision Palteoer. Part II., p. 116.

Calyx obconical, higher than wide ; the sides distinctly convex, section
across the costals sharply pentagonal, and across the distichals decagonal ;
the radials marked by very prominent rounded ridges; the interradial spaces
depressed. Narrower and more angular ridges pass out to the sides of the
radials, where they meet with others from the interbrachials, dividing the
surface of the dorsal cup into numerous triangular depressed areas, which

* Monogr. Echinod. Eifler Kalk., p. 61.

^}4

i^ii!

MEL0CRINID7E.

283

are thickly covered with fine granules, procluci/ig n most beautiful onitv
mentution.

Basalt small, forming a short cup; the columnar attachment small; the
axial canal pentalobate. Radials and costals large, as wide as long. Dis-
tichals two or 3 X 10, somewhat smaller. Palmars three to four in the calyx,
decreasing in length upwards ; the upper plates of the two inner divisions
axillary, supporting two arms, tho^e of the outer divisions quadrangular,
bearing a single arm from the calyx. Arm openings thirty, diiectod up-
wards and not visible from a side view ; the arms are not preserved in any
of the specimens. Interbrachials : 1, 2, 3, 3,3; followed by other minute
pieces, which pass into the disk. Anal side wider : 1, 3, 4, 4, etc. ; the first
plate larger than the corresponding plate of the other sides, and there being
no anal ridge. Ventral disk very short, almost flat; the interambulacral
spaces depressed. Surfiice covered by hundreds of very minute pieces with-
out orals, the plates being so small as to be readily taken for mere granules.
Anus excentric, placed at the summit of a small protuberance. Column
unknown.

Horizon and Locality. — Niagara group; Waldron and Hartsville, Ind.

18SS.

Mariacrinus Warreni Rinoueberg.
Plate XXII. Fiff. I.

RiNOUEBEno ; Proceed. Acad. Nat. Sei. Pliila., p. 133, Plate 7, Fig. 4.

Of the type of M. Carleyi, but having two distichals instead of three, and
no palmars in the calyx. It also diflers from that species in the details
of its ornamentation. Calyx obconical, slightly contracted above the second
costals. Radial ridges rounded, wide and quite prominent ; the surface finely
corrugated ; and there are series of smaller transverse ridges meeting those
from the interbrachials.

Basals four, forming a conical cup. Radials and costals comparatively
large, wider than high. Distichals two, rather small. Palmars two or three
in the calyx; in form resembling arm plates, but longer. Arms twenty;
long, slender, tapering gradually to a sharp point ; the joints short, quad-
rangular ; their upper and lower faces almost parallel. Pinnules delicate,
long, closely packed ; composed of joints twice as long as wide. The arrange-
ment of the interbrachials cannot be accurately ascertained from the speci-
men, but it is apparent that the proximal plate at all sides rests upon the

■ 1

284

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Ill

sloping upper faces of two radials. Neither is anything known of the con-
.struction of the disk. Cohimn round, of moderate size, slightly tapering
downwards ; near the calyx the nodal joints are somewhat larger than the
internodal ones, but at a length of about three inches all joints are of nearly
equal size.

Ilorkon and Localit//. — Niagara shale ; Lockport, N. Y.

Tt/pe in the collection of Dr. Eugene Ringueberg, Lockport.

Mariacrinus plumosus* Hall.
Piaic XXIII. Figs. 6 and 7.

1859. Hall; Puliront. New York, Vol. III., p. 110, Plate 3, Figs. 6-11.
1881. W. mid Sp. ; Uevisiou raltcucr. Part II., p. 116.

A small species. Dorsal cup apparently obconical ; the surface orna-
mented by strong radiating ridges, proceeding from the centre of the plates
to adjoining ones. Basals about as long as wide. Kadials a little longer
than wide. Costals nearly as large as the radials and of similar form. Dis-
tichals 3 X 10, eacli row supporting two arms, twenty in all. Arms simple,
rather long, composed of slightly cuneate joints. In the two outer arms, the
second joint gives off a pinnule to the outer side, the third is a hypozygal
joint, and the fourth gives off the second pinnule at the inner side; all suc-
ceeding joints being pinnule-bearing. The two inner arms, according to
Hall, support no pinnules up to the eighth joint, but this needs confirmation,
luterbrachials, 1, 2, 2, 2. The arrangement of plates in the anal interradius
and construction of the ventral disk unknown. Column round, compara-
tively large.

Ilorkon and LocalUy. — In the shaly layers of the Pentamerous limestone,
Wheelock's Hill, Litchfield, Herkimer Co., N. Y.

(?) Mariacrinus ramosus* Hall.

1839. Hall ; Palieont. New York, Vol. III., p. 147, Plate 2, Fig. 6.
18S1. W. and Sp.; Revision Palseocr., Part II., p. 116.

Dorsal cup urn-shaped, the rays marked by strong ridges, which pass into
the arms. Basals small. Eadials and costals higher than wide. Distichals

* We are somewliat in donbt as to the generic relations of this spceics, and think it possible from Hall's
fi^nre lliat it may possess infinbasnls, and therefore belong to a different genus. We do not reproduce the
(iriginiil figure, because it does not agree with the description, cither in the arrangement of the plates in the
calyx, or the construction of the arms. We had no opportunity to see the typo specimen, and only can give
an abstract of Hall's description.

:i-

i" ■

;. t.

MELOCRINID^.

285

3 X 10, each serio? supporting two arms, or twenty from the calyx. Tlie
two inner arms branch three times, the outer ones reuuiin simple. Above
the lust bifurcation, according to Hall, the arms are composed of a " double
serico of wedge-formed plates, and below these points of a simple series of
quadrangular plates," with rounded pinnules.
Horizon and Locality. — Same as last.

Mariacrinus aureatus S. A. Miller.

(After Miller.)
1801. Adv. Sheets 17th Rep. Geol. Surv. of Indiana, p. 34, Plate 6, Fig. 36.

Calyx very small. Dorsal cup bowl-shaped ; plates covered with angular
ridges passing out from their centres. Basals four, unequal ; exposed
beyond the column. Radials the largest plates of the calyx, wider than
high. First costals a little smaller, their width greater than the length ;
pentangular or hexangular. Second costals as long as wide. Distichals two
in the three anterior rays, three in the posterior ones ; the second plate of
the former axillary. Interradial areas elongate, subovate. Regular sides
composed of seven or eight plates : 1, 2, 2, 2 ; the first nearly as large
as the radials. Interdistichals one or two. Tlie anal side has nine or ten
plates, there being three in the .second, and four in the third row; the plates
of the upper row very small. Arm structure and tegmen not preserved in
the specimens.

Horizon and Localiti/. — Niagara group ; St. Paul, Ind.

MACROSTTLOCRINUS Hall.

1852. Hall; Piilicont. N. York, Vol. II., p. 203.

1S57. PiCTET; Traite de Pnleoiitolngie, Vol. IV., p. 329.

1802. DujARDiN and Hupe; Hist, ualiir. dcs Zoopli. Ecliin., p. 149.

1863. Hall ; Trans. Alb. Inst., Vol. IV., p. 207 (Abstr. p. 12).

1879. Hall; Mus. edit. 28th Rep. N. Y. State Mus. Nat. Hist., p. 128.

1879. Zittk.l; Handb. d. Pala-ont., Vol. I., p. 308.

1881. W. and Sp. ; Uevision I'nlaiocr., Part II., p. 102 ; also Proceed. Acad. Nat. Sci. Phila., p. 270.

1881. Hall; lllh Ann. Rep. Geol. of Oliio, p. 256.

1882. Ringuederg; Joiirn,Cinein. Soc. Nat. Hist., Vol. V., p. 119.

1882. JjE Loiuol; Paleont. Fran9aisc, Tome XL, Crinojdcs, p. 50.

1883. W. and Sp. ; Revision Palaiocr., Part III., p. 102; also Proceed. Acad. Nat. Sci. PIiila.,p. 324.
Syii. Actiiiocriiiusi (in part) — Lvon; Proceed. Acad. Nat. Sci. Phila., 1801, p. 411.

Syn. Cijathocrinm (in part) — Hall; Doc. edit., 2StU Vol., N. Y. State Mus. Nat. Hist. (Explana-
tion of Plate 13).
Sjn. Clenocrims (in part) — Suumard; Trans. Acad. Sci. St. Louis, Vol. II., p. 360.

286

THE CRINOIDKA CAMERATA OF NORTH AMERICA.

Specimens small. Calyx obconical to subglobose ; generally with promi-
nent rklges along the radial and anal plates j the surface densely coverod
with very fine striaa or small granules.

Basals three, large, unequal, forming a more or less deep cup ; two of
the plates equal, the other one half smaller. Radials very large ; their upper
corners but slightly truncated by the interbrnchials. Costals two, small ;
rarely more than one third the size of the radials, and in some- species still
smaller. Of the distichals genendly only the first jjlatc takes part in the
calyx, but occasionally also the second. Arms ten, long, biserial, and simple
throughout. Interbrachials few. Anal area much the widest and quite
distinct. It has three plates in the first row, of which the middle one is
placed against the sloping upper faces of the two posterior radials; while
the two smaller ones at the sides, together with the first costal, occupy the
upper face of the plate, in a similar manner as the corresponding plates of
the PlatycrinidaB, except that those of Macrostylocriinis do not extend beyond
the limits of the dorsal cup. The middle or anal plate is generally followed
by one or two other anals, longitudinally arranged. Ventral disk low; com-
posed, so far as observed, of small irregular pieces. Column round ; axial
canal small.

Distribution. — Restricted to the Niagara group of America.

Tyjie of the genus : Macrostyloerimis ontutus Hall.

HemarJcs. — This genus differs from all other Melocrinites in the number
of basals, and in having in the anal interradius three plates in the first row,
while the others have but one. The anal side of Hall's diagram on page 130
of the 28th Rep. N. Y. State Museum is incorrectly given, and it appears
from the description that Hall was not aware that in Macrostylocrinus the
arrangement of plates in the anal interradius differs from that of the other
sides. The basals in that diagram are represented a.s equal, while in fact
they are unequal, two of them being larger than the third.

Shumard regarded this genus as identical with Ctenocrinus Bronn, from
which it differs in the construction of the anal interradius — the latter
having but one plate in the first row — and also in the number of basals.

MacrostyloorinuB ornatus Hall.
Plate XXIII. Figs. 8a, h, c.

1851. Macroslylocrinus ornatus — IIai.l ; Pulocoiit. N. Y., Vol. II., p. 204, Plate 46, Figs. ^a-g.
1S66. Ctenocrinus ornatus — Shumakd; Trans. Acad. Sei. St. Louis, p. 301.
1881. Macrostylocrinus ornatus — W. and Sp. ; licvisiou Pulieocr., Part II., p. 103.

MELOCRINIDiE.

287

Dorsal cup about as high as wide ; cross-section siibpentangular ; tlio
median portions of the basals and costals slightly elevated ; their surfaces,
and those of the radials, covered with fine, interrupted strioc, and the inter-
brachials with elongate tubercles, which at the centre of the plates become
obsolete. The suture lines well defined.

Basals not as large as in some of the other species, forming a shallow
basin with obtuse upper angles. Eadials more than twice as large as the
costals, slightly spreading ; the upper faces somewhat shorter than the
lower First costals hexagonal, their upper sloping faces much shorter than
the sloping lower ones ; the second costals smaller than the first, the upper
side obtusely angular. Distichals free above the first ; the three proximal
plates quadrangular, the edges of their upper and lower faces crenulatcd ;
the succeeding three or four plates cuneate, and the plates above interlocking
so as to form two rows of arm plates ; the latter covered by two rounded
tubercles, transversely arranged, and placed in rows longitudinally. Arms
ten, long and rounded. Regular interbrachials three known ; the lower
plate twice as large as the two upper ; the latter resting against the sides of
the second costals, slightly touching the first. All other parts of the species
unknown.

Horizon and Localifi/. — Shales of the Niagara group ; Loekport, N. Y.

liciiiarJis. — We have been imable to trace the type specimen, and our
description was made from Hall's figure in the New York Report.

Macrostylocrinus striatus Hall.
Plate XXII. Figs. 14a, b, c.

1863. Ham.; Trans. Alb. lust., Vol. IV., p. 207 (iibstr. p. 13).

ISfiB. Siii'Mard; Trans. Acad. Sci. St. Louis, Vol. II., p. 361 {Clenocriims striatus).

1870. Hall; 28tli Rep. N. Y. State Mus. Nat. Hist. (.Museum edit.), p. 129, Plate 13, Figs. 1-4.

1881. \V. and Sp.; Revision Palajocr., Part II., p. 103.

ISSiJ. Hall; 11th Ann. Rep. Geol. and Nat. Hist., Oliio, p. 257, Plate 12, Figs. 1-4.

Calyx to the bases of the arms pyramidal ; the sides slightly convex ; the
fixed brachials formed into broad rounded ridges, which pass up to the arms ;
interradial spaces somewhat concave, except at the anal side where the
median portion is slightly bulging and angular. Surface of plates covered
by fine undulating striae or series of granules, about twelve of which traverse
the lower half of the radials to the basals; another set passes up to the
costals, and a third and fourth transversely to the sides of adjoining radials.

!^:f

288

TIIK CRINOIDEA CA5IKRATA OF NORTH AMERICA.

Eiieh lino of the transverse sets meets one of the longitudiniil lines at riglit
angles or less, and the apices of these angles lull into lines from the centre
to the corners of the plates.

Basuls large, forming a flat basin; column facet small and slightly pro-
jecting ; the upper margins distinctly pentangular. Kadials large, even for
the genus. Costals ciu'ved like arm plates; the first less than one fourtii the
size of the radials. The fust palmar, which bends slightly outward, included
in the calyx. Structure of arms unknown, but there were apparently two
arms to the ray. Interbrachials in two ranges, composed at the regular
sides of one plate each, of which the second is considerably smaller. The
anal side, which is much wider, is composed of three plates in the first
row ; the median one larger and wedged in between the sloping sides of
the radials ; the second range consists of five smaller plates, irregularly
arranged, and followed by still smaller pieces.

Horizon and Locality. — Niagara group ; Waldron and Hartsville, Ind.

Remarks. — This species is allied to M. ormiliis, but differs in the propor-
tions of the plates and the absence of radial ridges. The specimen figured
by Hall in the 20th Rep. of N. Y. State Cabinet on Plate 10, Fig. 7, under
M, striafiis, seems to us to differ essentially from that species in the propor-
tions of the plates, and may oven belong to a different genus.

Maorostyloorinus fasoiatus Hall.
Plate XXII. Fi(j. 13.

1S7C. Cyathocrinui faseiatu> — 'nK\.\.; Doc. edit. 28tli Hep. N. \. Sln:c Museum Nat. Hist., Plate 13,

Figs. 5 aiid (without description).
1879. Maerostyloniiius fiisria/in — IIai.i.; .Mus. edit, of same Kop., p. 130' mid lltli Ann. Rep. Gcol.

and Nat. Hist. Ohio, 1882, p. 238, Plate 12, Figs. 5 and 0.

Calyx subovoid ; height to width as ten to seven ; rounded to two third.s
the length of the radials, cylindrical above ; arm bases but little projecting ;
ventral disk almost flat. Surface of plate.s densely covered b^- fine, waving
striae, which radiate in fascicles from the basals to a place a little above the
centre of the radials, whence other bundles pass out to the intcrbrochials
and adjoining radials. In addition to the 8tria3, the surface is marked by
indistinct ridges, which follow the median line of the fascicles, and produce
a well defined stellate prominence upon the basal cup and upon each radial
and first interbrachial plate. The ridges upon the costals are the most
prominent, and increase in width on approaching the arm bases.

MELOCRINID^E.

289

Biisuls largo, forming a roundod cup, with a narrow coliuiinar ivttochtncnt.
Riuliiils unuHually largo, I'ully four tiuics the size of the cowtnls, and about
three times as long; very little sloped to meet the first interbrachial. First
costala somewhat larger than the second. The two proximal paiinars incor-
porated into the calyx, the others free. Arms ten. Interbrachials compar-
atively small, one and two at the regular sides; the nnal side wider, and
composed of three plates in the first row. Ventral disk constructed of small
irregular pieces.

Horizon and Locnlity. — Same as last.

Remarks. — Hall's figures 5 and 6, on Plate 13 of the 28th Rep. N. Y.
State Museum, are incorrect and misleading. The first costals are represented
twice as large as they actually are, and the ornamentation is also somewhat
different in the specimens. In the 20th Rep. of the same series, Plate 10,
Fig. 1, Ilall figures a cast from the Niagara group of Racine, Wise, described
on page 379 under the name o? Actinocrlnvn (Saccocrinus) semiradkUts, which
may possibly bo a large example of this species.

Maorostyloorinus granulosus (Hall),
Plate XXII. Figs, loa, h.

1879. Maeroslflocriiiui itriatus, vnr. granutoiu) — Uall; 28iIi Ucp. N. Y. State Mus. Nut. Hist. OIu-

scum edit.), p. 129.
1885. M. atrialus, XM. granulosus — W. and Sp. ; Ucvisiou ralivocr., I'nrt III., p. 102.

A more slender species than the preceding. Dorsal cup obconical ; its
sides nearly straight, .spreading gradually and uniformly upwards ; cross-
section at the top of the costals decidedly pentangular ; the basals and nil
plates following the rays marked by broad, rounded ridges. Another promi-
nent ridge pas.sos from the anus downward to the middle of the proximal
anal plate, where it bifurcates to adjoining radials. Narrower ridges connect
the radials laterally, and form a well defined boimdary line between the
upper and lower portions of the dorsal cup. The general surface is covered
by fine wrinkles and indistinct striae ; those following the radials and costals
longitudinally arranged, the others meeting within the middle of the plates.

Basals and radials smaller than in the preceding species ; the latter plates
about as wide as long, subquadrangular, and but very little sloped at the
upper corners. First costals less than two thirds the length of the radials,
and considerably narrower; second costals shorter and narrower than the

(

290

TIIK CUINOIDEA CAMKRATA OF NOllTII AMKRICA.

fivnl, thuir iippor iiiiyles nciito. Arms two to the ray, ireo above the firxt
plutu, wliieh is longer tliun wide. The nriiiH, nccording to Hull, arc long,
blender, and simple. Regular interbrachiuis slightly convex ; arranged : 1,
2, ;]. Anal iiiternidius much wider, composed of three plates in the first
range ; the middle or anal plate longer than the two at the sides and fol-
lowed by a second anal piece, of which the top is on a level with the top of
tiio interbrachials of the third range. Structure of ventral di.>'k unknown.

Ilorkon and Loculitij. — Same ns last.

Jieinarks. — Prof. Hall uuide this species a variety of M. ulriatits. It is,
however, suflicienlly different to be recognized as a distinct species, which
we believe is more nearly related to M./aseiuhis than to M. striutus.

MaorostylQorinuB Meeki (Lvun).
Flute XXII. Fi</a.I6a,b.

ISOl. Aetinocrhm Meeki — I.vox ; I'rocced. Acad. Nut. Sci. I'ljiln., p. 411, Plntc 4, Figs, ia, b.
1S81. Macrosl^lucriiim Meeki — \V. mid Si'. ; llcvisiuii I'nla'ocr,, I'lirl II., p. 103.

Calyx subglobose, about as wide as high ; cross-section slightly pentangu-
lar. A well defined ridge rises from the column, follows the median lino of
tiie various radial plates, and passes into the arms. The rie, which is
ratlier obscure upon the basal."*, gradually increases in size, and grows quite
prominent upon the costal^*. Smaller ridges proceed from the centre of the
radials to the interbrachials, and form with tlio larger ridges numerous
obscure triangles. The inner spaces of these triangles are occupied by fine
closely arranged striae, which form additional triangles one within the other ;
there being five such sets of triangles around the column, which extend to
the middle of the radials, and are larger and better defined than any of the
others.

Basals forming a shallow basin, rounded at the bottom ; the column facet
slightly concave. Radials fully four times as large as the first costals, and as
long as wide. First costal narrower than the second, and fully twice as wide
as long; the second somewhat larger, its sides spreading rather abruptly
upwards, the sloping upper faces concave and forming an acute angle. First
interbrachial large, a little longer than wide, resting against the distinctly
sloping !<ides of the radials, and rising to the top of the second costals ; the
succeeding plates much smaller. The arrangement of plates at the anul side
is not known ; neither is the construction of the ventral disk nor the struc-
ture of the arms.

MKI.OCRINID.E.

291

Ilorhon and LnrdHh/. — Ningara group ; .TcfTcrxon Co., Ky.
TiJiiiH in tho Knapp collection at the Borden InHtitutu of New Provi-
dence, Ind.

MaoroBtyloorlnus AiBibraohiatus UiKnrEnp.Ro.
Plate XXIII. Fiifs. 9 & 10.

1891. BiNoi'Ernno ; Jdiirii. Ciiiciu. Snc. Nat. Ili»t,, Vol. V., p. 110, Plato S, Fiff. 1.
1885. W. iiJiil Si'. ; Uevi«i(>ii ralitocr., I'lirt 111., p. 10*.

Larger than the preceding species, and proportionally broader. Dorsal
cup apparently bowl-shaped — tho exact form not being ascertainable owing
to the crushed condition of the specimen ; interradial spaces depressed ; sec-
tion subpentagonal ; surface of plates covered by numerous small, irregu-
larly arranged granules.

Basals of moderate size, forming together a rapidly spreading pentagonal
cup ; the column facet surrounded by a small rim, formed by a row of sninll,
closely arranged nodes. Radials large, wider above than below, subtiuad-
rangular; the upper corners slightly truncate. First costals quadrongular,
less than half the size of the radials, nearly twice as wide as long. Second
costala smaller than the first, and considerobly shorter. Distichals free after
the second plate. Arms ten, long, massive, widest in tho middle, and taper-
ing at both ends. The two fixed distichals are followed by a few much
shorter cuncate pieces, and the latter by two rows of short transverse ])lates,
alternately arranged and united by a zigzag suture. Regular interbrachials
five in three ranges ; the first plate large and oblong ; the arrangement of
tho anal side unknown. Column round ; the edges of the nodal joints sur-
rounded by small nodes.

Horizon and Loccditi/, — Niagara group ; Lockport, N. Y.

T/jpe in the collection of Dr. E. N. S. Ringueberg.

Remarks. — The specimen illustrated by Fig. 10 differs slightly from the
type, being smaller, and having a more elongate cup, less massive arms,
and proportionally higher costals. But as it is of the general habitus of
this species, we take it to be a young specimen of the same.

I: I

39S

THE CUINOIDEA CAMEUATA OF ^UK^H AMElllCA.

MELOORINUS GuLoru**.

ISiO. CJiiLDrrMi IVtrt'f. (itTiiiniiiir, Vol. I,, |i. 107.

It.'IS. AiiAKSI/. 1 Mi'iii. ilr lit Sue. (Ii'» t<n. iiiiliir. di' Ncuclmli'I, Vnl. I., p I'Jfl

IHMS. (ioi.nniM i Ndvii A'iii, Anul. l,iMi|iiililiim, V(il. XIX,, 1,, ji. 33tf.

IMl. MCi.i.KHi MdiiiiUlxr. il llirliii. Akiidiniii', p. <()U.

iHtO. D'OiiiiKiNy ; Cmrn ('li'mciit., Vol. II., p. I M).

Uii. Qiknutkut; IIiiimH) >I. IVlirl'iii'liiikuiiili' (Aii«i;. I ), \>.iVii).

18.55. Kokmkk; I.clliiirn (icoKiio'ilica (Aio^. II). p. i'M.

IS.'JT. I'ktp.T! Triiilodu I'al.'oiil., Vol IV., p. .U'J.

1802. DrjAiiDi.H uiiil Uvvi:; llUt, imliir. iUh /.oophyiivi, p. lit.

1807. S( IIDI.TZK; Moiionr. Kc'hinoil, Kill. Kiilk,, p. «1.

18*8. Amiki.in; Iniiioitr. Criii. Sure , p, 19.

1S70. /ITTKI,; llaihlli. il. I'uliroiit., Vol. I., p. 371.

1S81. W. mid Sp. ; IVonrd. Arad. N»l, S,i, I'hilii , p, 202

1881. W. mid 8i'. ; Urvl-ioii I'aliincr . Part II., p. U^.

1881. Dl Ldiiloi.; I'alroiit. Friiiiviiiii', Toiiiu \l. (Criiioidrn), p, 89.

1895. W. mid S\\ ; I'roc.Til. Acid. Nat. Scl. I'liila., p iWfl.

1883. \V. imd Sp.; Hcvi.tloii TaWorr., Part 111,, p. 101.

1885. Quenstkiit; llaiidl). d. Pi'lri'l'ai'lciikiiiidc (Aiik|{. 3), p. 03*.

1830. S. A. Mil.r.Kit ; N. Amcr. (Iced, mid Pal il., p. 201.

8yn. CleiiiirriiiHS Hhiinn ; IHIO, .lalirli., p. tvU; nl»i> MiilltT, 1S55, Vcrli. nnturli. Vcroiii, \ ,.1. XII.,
p. II), and Nuuu EuliiiKid. Kill., Kalk., p. 255 ; nlao Follmaiiii, 1857i UiitcnlcToiilBclio Crmoidi'cn,
p U.

8yn. Cdn/iitiocriiiu) Uokmeii; 1S55, LpIIi. OroRii. Vol. II., p. 252.

S.vii. MiiriiiniiiiiH llvi.r. (in pari); 1837, I'alii'oiit. N. Y., Vol. 111., p. lOt.

Svii. Ci/toiriiim Kukmkii; 1S(J(), Silur. Fniiim West. Tonn., p. 4(1.

Sjii. ('/aiioiriiiiu Okmlkkt; 1S7'J (not Qnriisti'dl), Soc. (i*''(d. dc Kranrc (sh. 3), Vol. VII., p. 9.

8)11. THi-hiiiiirriiiilfn Thoosti 1830, l,Ut of Criii. Trim, (not dt fined).

Sjn. A'IrDi-rimlpfCmKKw; Ann. ficol. Hop. N. Y. of IHjn to 1S41 (not C;inihprlnnd, 1*^20, nor
Antlin, 1842, nor Kllic'rid({p, .Inn., Is*!), nor Anlemerinui Miiusler, 1839, nor Ljon, lS37, nor
.t-i>iocrittm Ether, nnd Carpenter, ISSO).

Ciilyx obconiciil, siihglobosc or pyriform ; the rays extended into free
tubular nppoiuliigeH boiiring arin.s on both sides. Ba.si\l.s four, unequal ; three
of them (juachangidar, tlio anterior one Uyger and pentangular. RadiiilH in
contiict laterally ; four of them heptagomd, the anterior one, which rests
squarely upon the anterior ba.<fal, hexagonal. First costal hexagonal, the
second, which is axillary, generally pentagonal ; the sloping faces of the
latter may be equal and support two rows of distichals, or unequal, when
only the longer inner face is foUowed by distichals, the shorter outer one
giving off the proximal arm. In the former case, which is the general rule,
the distichals constitute ports of the calyx, and both series terminate in
axillariea, which give off foward the inner side of the ray in a nearly verti-
cal direction an indefinite number of brachials of successive orders, and
toward the outer side a sloping arm from each order. The plates of the
different orders are short and consist of two parallel series, which form two
arm-bearing trunks. The two trunks, as a general rule, meet laterally by

&-.%•-

MKF.OCniNin.K.

2on

■utiti'o, nn<l form togctlicr rij^iil tiibiiliir nppondngof*, wliifli piiss out iViiiii tlm
cn\yK upwni'ilH. In hoimo ciihuh tlio cuniu'ction of tliu nppuiuliig<-s is iulii-
ruptod for nliort (liMtaiiceM, but, no fur iw known, nil of them coim- tojjollior,
Bnd nro nnitod towiinl tin* nppiT part. Fiom tlicsi! nppcniliigt-H tliniii^'lioiit
tli<'ir '"»n length, lit ccrtnin inlcivul.'*, iinil from ojiposito pliitfH (nut nltor-
Pivtely) nn* givon oil' wt'il (IcCiikmI MHi'iial arnin, bearing piiiniik's on altcrnatt'
Bldcf.i, A »<liglit (li'partnrc in tlio coiiMtrnction of tlio main trunks occurn among
ppocloH in wliicb tliu proximal arms aru givon ofT alroady from tlio flrxt
nxillarioH, /.('., from llio oostaln. In tlioso species tlio trunks nt tlic dorsal
surfaci! iiro composud ofbut a winglo series of plates, and the pinnide-bearing
arms are arninifd alternately as in Shijinincriniin sml/ihiK. Tlie ventral sur-
facoM of the appendages are roofed over in all canes by rigid covering plates.

Intorbracliials numerous ; the first placed ujjon the sloping upper faces
of tlie radials, followed by two plates in tlio second row at the four regular
Bides, three plates at the nnal side, and a greater or les- number of irregular
plates above, which meet with the inteiambulacral plates. Ventral disk
highly elevated or scarcely convex ; tho orals In some species largely de-
veloped, in others indeterminable. Anus cxcentric and generally — jierhapH
always — extended into a small tube.

Column round, composed of alternate long and short joints ; axiid canal
Hmall.

Dint rihul ion. — Mvlorriniin ranges from tho Upper Siluiian to near the
close of tho Devonian, and is well represented both in America and Kurofie.

HeDKivks. — The genus Mi'lorrinus holds the same relation to Mitrinrrinus
that Stc(j'inocruiiis does to Ar/hwrrmus, and Fiirhifloen'iiiis to Plnl/jcrltiuK. In
all those typos tho construction of tho calyx remains relatively almost un-
changed, while a remarkable modification occurs in tho brachial appendages,
which are extended into tubular rays with an indefinite number of semi-free
brachials, giving off arms.

Several attempts have boon made to subdivide Melncrimin into two or
three genera. Roomer, in 1855, proposed the name CdstdiiocriiiKs for
species with a central or subcentral anal opening, retaining Mclnrriinix, with
M. hlern(jbiphicns Goldfuss ns type, for species with a lateral opening. Our
examination of the various species leads us to doubt whether such a division
can bo practically uphold. We agree Avith Schultze * that tho anus is never
central in this genus, nor in any case actually lateral, but its position is

• Moiiogr. Eifl. Knlkes, p. 03.

29i

THE CKINOIDKA CAMERATA OF NORTH AiMERICA.

always more or loss excentric. Neither can the presence or absence of inter-
ilistichiils, unless accompanied by other distinctive characters, be considered
sudicient for generic separation, as proposed in the case of C/eiioeriiius
Bronn.* Those plates are mere auxiliary pieces, which may be present
or absent in the same species.

Tiirhiiiocri'iii/cs Troost was proposed in MS., according to ITall.t for a
species which was said to have the first anal plate on a level with the
radials; but Tvoost's typical npccics, JItlocriinis Venu'inli, had no such plate,
or Hall could not have stated that the anal area was but slightly distinct
from tlie other four.

Ci/t'icniiiis was described by Eoemcr with three (?) basal plates — the
exact number not having been ascertained. A good specimen in our collec-
tion from Roemer's typical locality plainly shows four plates, and we have
no doubt the species is a Mclocrhms.

rhiJUjhtitrriniix McCoy is described with four basals, succeeded by seven
plates in the next ring, which shows that it is an abnormal specimen. If it
is. as we think, an Actinocrinoid, the abnormal seventh plate may have
necessitated the presence of a fourth basal.

In addition to the species herein figured and described, we note the
following ; Melocriinis ohpyrniuidalis Winchell and Marcy, M. Vcrncuili Hall
(not Oehlert). and ^^. mdomis Hall, which were described from unsatisfactory
natural casts. Neither can M. Praltciii {Forbcsiocriiiiis Pruffem) McChesney,
which was defined from a fragmentary specimen, or Mclocrinus sciilptus Hall,
of whicli only tiie ba.sal plates are known, or M. hrvidacti/lus Hall, which
was figured but not described, and the figure not properly published, be
regarded as good species.

* Tlio fjcinis Clfaoeriiiiii was at first incorrectly defined. It was dcscril)cd liy Bronn, 1840 (Jnlirbucli,
p. .542), with tlirce b.-isal pliitos, and this number was confirmed by llocmer (liCtliacn Gcogn., 1855, p. 251).
Subsequi'iilly dc^ Koninck considered tlic genus idonticid witli Pradocriiiiis Ue Vcrnenil, whicli actually lina
three basiils. Job. Miiller (,Verhaniil. niiturb. Vcrein, 1S5,")) admits more than three basals, probaldy five,
,ind in ]S.j7 (Neue Echiuod. Kifi. Kalk., p. 255), assorts positively the presence of five basals. lie com-
pared Cti-iioeriiiHS with Gli/plorrhiiis Hall, and supposed both to have " parabasalia." Sehnltze afterwards, in
his Monograph, p. (Vi, proved from more perfect specimens that Clcnorrinus fj/pun has bntyi^wr basals, and no
infrabasals, and referred that si)ecics to Meloerinm. Follman, in bis article ou the " Uuterdcvonischeu
Crinoideen," Verhandl. Naturli. Vcrein, 18S7 (private cd., p. 11), revised the genus Clenocriiiui with four
basals, but pointed out no characters by which it may be distinguished from MelocriHut.

t 28th Kcp. N. Y. State Mus. Nat. Uist. (Museum edit.), p. 139.

MKI,ocRI^'II).^•:.

295

MelocrinuB nobilissimus (Hall).
Plate XXIII. Fiys. la, 2, 3.

1850. }[(iriacnnm iioliilisiiimiis — llxLh ; I'iik'oiil. N Y., Vol. 111., p. 10 J, riiite 2, l'ii;s. l-l, ami I'liitc

2A, Fig. 1.
ISSl. Metofrinus iiobilisaimus — W. ami Si-. ; Kcvisiou I'aliEocr., rait II., p. Mi.

A rather large species. Dorsal cup higher than wide, obconical, obtusely
pentangular above the costals owing to a ilcpression in the upper portions
of the interradial spaces. The tubular appendages supporting tlie arms con-
sisting of two contiguous trunks, wliich are composed dorsally of two rows of
plates. Plates marked with obscure radiating ridges ; the suture lines well
defined, with a shallow pit at each angle.

Basals wider than long, formed into a small subcjlindrioal cup, not pro-
jecting beyond the column. Radials larger than the costals, about as wide
as long. The second costals with an obtuse angle above. Disticlials 3X 10,
about half the size of the costals, the upper ones axillary and supporting
upon their outer sloping faces a lateral arm, of wliich the four or five proxi-
mal plates, which are longer, are incorporated into the calyx ; wliile the inner
sloping faces are followed by a row of from six to seven palmars. The latter
form a vertical line with the disticlials, and tiic plates of adjoining divisions
are connected laterally, except the two proximal ones of oni'li side, between
which are interpo.sed small irregular interdistichals. The fourth and fifth
orders of brachials consist of five plates, the sixth and all orders to tiie niutli
of four, the succeeding ones of three, and those near the top of but two
pieces. The brachi Us are arranged longitudinally, and connected suturally
with those of the opposite branch, so as to form a compound, free tubular
appendage, from which the arms arc given off at opposite sides, the axillaries
supporting on tiieir longer sides the next order of brachials, and on their
shorter ones an arm. There are about thirty arms to each side of the ray,
rising to the same general height; all composed from the second plate up tif
two series of interlocking pieces, and all pinnule-bearing. Eegular inter-
radial spaces narrow but long; the first plate rests within a deep notch
between two radials, and is somewhat larger than tlie others ; the succeeding
ones are not arranged in horizontal rows, but alternate witli one another ;
they are hexagonal, and the upper lateral faces of the one plate resi against
the lower lateral faces of the other, thus forming two longitudinal rows side
by side, each composed of about twelve plates, which decrease in size

296

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

upwind. Anal intermdius considerably wider, and flattened instead of being
grooved as in the case of the other four ; the first plate is the largest, and is
followed by tliree pieces in tlie second row, and these by three or four pieces
in the succeeding rows. Interdistichals four, rather large and longitudinally
arranged ; the upper one resting between the two proxinuil palniars. Nothing
is known of the ventral disk, nor of the anus. Column large, round, com-
posed near the calyx of moderately long joints alternating with shorter ones ;
suture lines distinctly waving.

JIufizon and Locality. — Pentamerus limestone ; Litchfield, Herkimer
Co., N. Y., and apparently also found in the Niagara group of Western
Tennessee.

T^jics in the American Museum of Natural History, New York.

Melocrinus paohydactylus (Co.vrau).
Plate XXIII. Figs. 4 and 5, and Plate XXIV. Figs. 4a, b.

1S41.

1S59.
1831.

Js/rocriiii/es paciytlae/ff!ii» — Conrad; Aun. Rep. Pnlscont. N. Y., p. 34. Also Mather 1843;

Geol. Rep. N. Y., p. 216.
Miiriiicriiiiis pacliydaelylus — Hall ; Palreont. N. Y. Vol. III., p. 107. I'liite 3, Tigs. 1-4.
Jlelocriiius pachydaclj/lua — W. mid Sp. ; Revision PiiliEOcr., Part II., p. 122.

Syii. Actiiiocriniis polydartyhn BoNNY (not S. A. Miller) ; Sclieneetady Reflector of 1835.

Sjii. ilariucriiiiis paucidacli/lus IIall ; Palrcout. N. Y., Vol. III., p. 109, Plate 3, Fig. 5.

Sjii. Melocrinus paucidacti/lus — W. and Sp. ; Revision Paltcoer., Part II., p. 122.

Smaller than the preceding species ; dorsal cup shorter and with convex
sides ; interradial spaces not grooved, although slightly impressed in the
uppe>' portions ; the radiating ridges upon the surface much more conspicu-
ous, and ending m a node at the centre of the plates ; the arms given off at
greater intervals, and the pinnules less closely packed together than in that
species.

Basals formed into a short spreading cup, of which the lower margin
is slightly projecting. Radials and costals of nearly equal size, as wide
as long ; both covered by a broad, flattened ridge, which bifurcates on the
second costal and follows the distichaLs. Narrower ridges pass out to the
intcrbrachials. Distichals 3 X 10, smaller than the costals. The axillaries
support upon the inner sides of the ray from seven to eight palmars, which
are laterally connected ; at their outer sides the proximal arms, of which
the five lower plates are considerably the longest, and form part of the calyx.
The two lower palmars of each side are longer than the upper ones, and
those of the one division are separated from those of the opposite side by a

H-

MELOCRINIDiE.

297

small interdistichnl. The surface of these plates is covered by radiating
ridges and nodes ; while that of the succeeding ones is without ornamenta-
tion, and the plates are transversely arranged. The brachials of the fourth
order consist of six plates, those of the succeeding ones of five, rarely four
(so far as observed) ; all transversely arranged, and suturally connected with
their fellows of opposite sides, forming five long tubular, arm-bearing trunks.
The arms of this species are more slender than in the preceding one, and
slightly more tapering, the pinnules longer; they are flattened on the back,
and the surface is corrugated. Interradial spaces composed of about twelve
plates arranged in two longitudinal rows, the plates alternating with one
another. The anal interradius and ventral disk are not visible in the speci-
mens.

Horizon and Localily. — Schoharie Co., N. \.; Lower Helderberg group.

Ti/pes in part in the American Museum of Natural History, New York.

MelOCrinUS bainbridgensis Hall and Whitfield.
Plate XXII. Figs. 4a, b, c, and Plate XXIV. Fig. 5.

1875. Melocrinus (Cleiiocrinus) bainbridgensis — Gcol. Surv. Ohio, Palicout., Vul. II., p. 158, Plate 13,

Figs. 2 and 3.
1881. Melocrinus buitibrittgensii — W. and Sp. ; Revision PaliBoci'., Tart II., l>. 121.

Sjn. Melocrinus Clarhei Williams; 1882, Proceed. .\cad. Nat. Sci. Pliila., p. 31.

Specimens above medium size. Dorsal cup as high as wide, rather rap-
idly spreading ; sides somewhat convex ; cross-section pentangular. Plates
slightly elevated, beveled at their margins ; the middle part a little depressed,
and covered with a system of confluent granules; the suture lines grooved.

Basals forming a low cup with a sm.all rim around the lower margin,
which is notched at the interbasal sutures ; axial canal pentalobate. Radials
and costals wider than long, decreasing in size upwards. Distichals 3 X 10,
those of the same ray in contact laterally, interdistichals not being repre-
sented ; the proximal one less than half the size of the second costal, and as
long as wide ; the two others much shorter. The third plate, which is axil-
lary, supports upon its inner face the next order of brachials, at the outer
the proximal arm which is free from its origin. The brachials of the suc-
ceeding orders also consist of three pieces, which are transversely arranged,
and those of the same ray are laterally connected, forming trunks from
which arms are given off at every third plate. The trunks taper upward, and
are deeply grooved along the line of contact of the two branches. Arms

J .

•)

tjmiii

298

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

thin, tliroad-like, with closely packed pinnules. Regular interbrachials :
1, 2, 3, and others above, which gradually intermingle with the interambu-
lacrals. The flrst interbrachial of the anal side is somewhat the largest, and
is followed by three plates in the second row, which form an arch, and by
four pieces in the third and fourth rows. Ventral disk low, depressed-pyra-
midal, apparently surmounted by a subcentral anal tube ; the plates more
or less uniform, of about medium size, and somewhat convex.

Iloraon and Locallljj. — In a limestone layer, six inches in thickness,
above the base of the Black Slates, Bainbridge, Ross Co., 0., and at Canan-
daigua, N. Y., in rock of about the same age.

Ti/pe in the Ohio State collection, Columbus.

Remarks. — Prof. J. M. Clarke of Albany had the kindness to send us
gutta-percha casts of the types of Melocrinua Clarkei Williams, which we
regard as identical with M. hatnl>rid(/emis.

Meloorinus gracilis AV. and Sp. (nov. spec).
Plate XXII. Fig. 5.

A rather small species, of the type of Melocriims (Ctcnocrimts) stellam
Roemer. Dorsal cup obpyramidal ; the radials and costals strongly curved
so as to form broad, very conspicuous longitudinal ridges with a small
tubercle at the centre of each plate, tho^ie of the axillaries being the longest
and sharpest. Interbrachial spaces depressed, giving to the section across
the second costals a sharply pentangular, somewhat stelliform outline.

Basal cup low, broadly truncate at the bottom, its lower edges slightly
projecting beyond the column ; the upper angles turned abruptly upwards.
Riidials and costals nearly equal in size, wider than long, but the curvature
makes them appear to be longer than wide. Distichals 2X10, rounded like
arm plates ; short, transversely arranged, those of the same ray separated by
one or two minute interdistichals, which rest within the bottom of a shallow
pit. The arm trunks bend outward, are heavy, and composed of two rows
of short pieces. The arrangement of the arms cannot be ascertained, as in
the single specimen the trunks are preserved only to the fourth plates, and
of the arms only fragments of a single one. Interbrachials numerous,
slightly decreasing in size upward ; arranged : 1, 2, 3, 3, etc. They are
somewhat convex and ornamented with obscure radiating ridges, which con-
nect with the interambulacral plates. Ventral disk elevated, and, so far as

MELOCRINID^E.

299

known, composed of rather small pieces. Form and position of anus un-
known. Colunm round, strong ; the nodal joints projecting, the intervening
ones knife-like.

Horizon and LocaUty. — Hamilton group ; Canandaigua Lake, N. Y.
I'ype in the collection of Prof. J. M. Clarke, now in the State Museum at
Albany.

Meloorinus Tiflfanyi W. and Sr. (nov. spec).
Plate XXII. Figs. 7a, b.

Calyx pyriform ; the sides nearly straight from the top of the basals to
near the bases of the arms ; the tegmen depressed-hemispherical ; cross-
section, as seen from above, obtusely pentangular. Surface of plates orna-
mented by faint ridges, radiating from near the centre of the plates to the
centre of adjoining ones.

Basals projecting laterally, forming four conspicuous, elongate nodes;
the lower part somewhat excavated for the reception of the column. Radials
and costals gradually decreasing in size upwards, about as long as wide ; the
second costals not more than half the size of the radials. Of the distichals
two plates are preserved ; the lower one fully one half smaller than the
preceding axillary ; the second short, shaped like an arm joint and curving
outwards. There are no interdistichals, all plates of the arm trunks being in
contact laterally. Interradial areas on a plane with the radials and costals ;
the first interbrachial tlie same size as the radials, and followed in the type
specimen by two plates at three of the sides, but in the posterior and right
antero-lateral interradius by three, and these by numerous rows of from
three to four plates, which connect with the disk pieces. Ventral disk
depressed-hemispherical, the plates very uniform, rather large, having the
size of the third row of interbrachials. They sire ornamented like the plates
of the dorsal cup, but are a little more convex. There are apparently no
orals. Anus excentric, probably connected with a tube. Arms unknown ;
column round.

Horizon and Locality. — Hamilton group ; New Buff.alo, lown.

T^2^e in the collection of Mr. S. A. Tiifany of Davenport.

300.

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

MelOOrinUB Calvini W. and Sr. (nov. spec).
Plate XXII. Fly. 6.

Similar to the preceding species, but the sides of the dorsal cup convex,
and the general form of the calyx subovoid ; the basals less projecting ; the
radials, fixed brachials and interbrachials — the latter to the third row —
crowned by a large, rather conspicuous rounded node without other orna-
mentation; the upper interbrnchial and interambulacrul plates a little
convex.

Bujsals projecting laterally, and forming four rather conspicuous nodes
around the columnar attachment which is a little projecting. Radials and
costals longer than wide. The distichals of the same ray in contact laterally.
Regular interbrachial spaces large, but slightly depressed between the arm
trunks; the plates arianged: 1, 2, 3, 3, the upper ones insensibly connecting
with the plates of the ventral disk. Anal interradius widest, having three
plates in the second row. Ventral disk short; the plates rather .small and of
uniform size ; orals apparently unrepresented. Anus excentric, probably at
the end of a narrow tube.

Horizon and LociiUt/j. — Hamilton group ; Johnson Co., Iowa.

Ti/pe in the collection of Prof. S. Calvin of Iowa City, in whose honor
this rare species is named.

MelOOrinuS oblongUS W. and Sp. (nov. spec).
Plate XXII. Figs. 9 and 12.

A rather slender species of less th.an medium size. Dorsal cup obconical ;
the sides straight to the top of the second costals, whence the rays turn out-
ward and form distinct lobes around the calyx, which give to the section
a decidedly pentalobate outline. Plates convex, a little nodose, but without
ornamentation.

Basals small, subequal, notched at the sutures; the lower face but slightly
truncate, and very little excavated. Radials and first costals generally
longer than wide, especially the former; the second costals often as wide
as long. Distichals 2 X 10, the two upper ones axillary and separated by
a small interdistichal. The arm trunks not preserved in the specimens, but
as there are two distichals, the trunks must have been formed of two rows of
plates. The first interbrachial as large as the first costal; succeeded by

, /

MELOCRFNIDTE.

801

rowa of 2, 3, 3, and three plntoH, which meet the interambuhicrals. Anal
interradius a little wider, with three plates in the second row, and four in
the third. Ventral disic low, irregularly convex; the ninbulacral spaces
slightly elevated ; the plates — orals included — alnio><t of uniform size.
Anus subcentral ; at the end of a tube.

Ilorizon and Locality. — Niagara group ; near Louisville, Ky., and St,
Paul, Ind.

Types in the collection of Wachsmuth and Springer.

Remarks. — This form was regarded by Roenier* as specifically identical
with his Cytocnus Icevis, which comes from the same horizon in Tennessee,
and resembles it in general form ; but the arm trunks of that species are
composed of single joints, and it has a smaller number of interbrachials.

Meloorinus Roemeri w. and Sr. (nov. spec).
Plate XXII. Figs. 11a, h.

Syii. Ci/iocriniis hefh — Roemkri 1800. Siltir. Fnuim West. Tcnii., p. Ifi, Plate 4, Figs. 2a, h, c.

Syii. Ctenoeriiim hevis — Siiumaud; 1800. Trniis. Acad. Sei. St. Louis, p. 301,

Sjii. Melocriiiiia licvis (not Goldf.) — W. and Sp. (iu part); 1881. Revision rnlicocr. Part 11., j). 122.

Calyx moderately small, turbinate ; dorsal cup about as wide as high,
gradually spreading to the arm bases, which are formed into five very con-
spicuous lobes, giving to the calyx, as seen from above, a decidedly stellate
outline. Plates without ornamentation, a little concave, except the median
line of the radial plates, which is obtusely angular. The radial ai)pendages
from which the arms are given off composed of a single series of plates.

Basals rather large, subequai, forming a shallow cup, which is slightly
truncate at the lower end, Radials twice as largo as the first costals, hexa-
gonal, about as wide as long ; their upper sloping faces a little larger than
the corresponding lower ones. Second costals very small and curved like
arm plates; their upper sloping faces unequal, that toward the outer side of
the ray much the longest, and supporting a distichal, the inner one the first
arm plate. The trunks, which consist of a single series of plates, give off the
arms at intervals from alternate sides, not from opposite plates as in species
with a double series. Interbrachial spaces wide, the first plate large, succeeded
by two rows of two and three plates respectively, which are followed by di.sk
plates. The two outer plates of the upper row curve outward and form the
sides of the lobes. At the anal side the first plate is larger, and foUoweti by
» Silur. Fauna West. Tennessee, 1860, p. 48.

302

TIIK CUINOIDEA CAMERATA OF NORTH AMERICA.

i *'

three plates in the second row, and four in the tliird. Ventral disk depressed,
pentagonal ; the anibulacral regions slightly raised above the general level ;
the plates without ornamentation, almost flat, and the sutures difficult to see.

The disk ambulacra are completely subtegniinal ; the orals apparently
unrepresented, and the anus is at the end of a large tube, which bends
toward the posterior side.

Ilurhon and Londilij. — Niagara group ; associated with Aistraospomjia
meniscus. Decatur Co., Tenn.

T//pe in the collection of Wachsmiith and Springer.

Itemurkn. — Roenier descril)ed this species as Cytocrinus Iccvis, mnkmg it
the type of a new genus. lie supposed it hud three basals, and he did not
understand its arm structure, which is evidently that of Mclocrinus. We
refer the species to the latter genus, but are compelled to change the specific
name, as Goldfiiss in 1826 described a Mdocrimis Iwvis from the Eifel, and
propose for it Mclocrinus Jiocmcri Roemer originally included in his species
two forms, the typical one from the Niagara group of Western Tennessee,
and another from the same horizon of near Louisville. The latter has been
described by us as Mchcrinus ohlonrjus. The two species resemble each otlier
in form, but 3[. uhlongus is considerably larger, the calyx contains many more
plates, and the radial appendages are composed of two rows of brachials in
place of one.

Melocrinus oboonious Hall.
Plate XXII. Figs. 10a, b, c.

1863. X'l'hrriiiiis ohnnicus — IIall| Tmiis. Alb. Tnst., p. ZOfi.

1875. Melucriiiim obroiiinia — WKLh ; 2Slli Ucp. N. Y. Slate M us. Nut. Hist., p. 138, Tlnte 14, Figs. 11-14.

1S81. Mtlucriniis obcomfiia—\\\u.\ IKli Ann. Hep. Geol. Ind. by Collet, p. 269, Plate 13, Fgs. 11-14.

18S1. Mariarriims obconieua — W. nud Sp. ; Uevision I'alicocr., Part II., p. 116.

Of medium size. Calyx obconical, about as wide as high; gradually
expanding from the top of the basals to the bases of the free appendages,
where it is distinctly lobed. Plates covered by numerous radiating ridges,
which pass out from the middle of the plates to the sides and angles, meet-
ing those of adjoining plates; the ridges passing up and down the radial
plates wider and somewhat higher. Besides these ridges the whole surface
of the plates — that of the ridges included — is finely corrugated, which adds
greatly to the beauty of the species.

Basals projecting, forming a short, indistinctly quadrangular, almost cylin-
drical cup. Radials and costals of about equal size, and all nearly as long

MELOCUIMDvE.

303

as wide. Distlchnls two, the two divisions separated by one or two iiiter-
distichals Palinars apparently not united laterally, and there may have
been two appendages to each ray Interradial spaces depressed in the upper
portions; arranged: 1, 2, " with numerous plates above, which connect
with others in the disk. A.. J area somewhat the widest, and with three
plates in the second row. Ventral disk almost Hat ; composed of very uni-
form, slightly convex pieces. Anus excentric, probably without a tube.

Horizon and Locality. — Niiigara group; Waldron and Ilartsville, Ind.

Tifpe in the American Museum of Natural History, New York.

MeloorinuB parvus AV. and Sp.
riatc XXII. FUj. 8.

1S92. W. mill Sp. ; Aincr. Geologist (September number), Vol. X., p. 141.

A small and very slender species of the type of 3Iclocriinis liocmcri, hav-
ing like that species five uniserial radial appendages. Dorsal cup obpyr-
amidal, the interradial spaces deeply depressed, and the cross-section at the
top of the costals distinctly pentalobate. The plates a little convex and
covered with obscure ridges.

Basal cup almost cylindrical, its upper end slightly the widest, the lower
face completely covered by the column ; the plates as high as the radials,
and the interba.sal and basi-radial sutures distinctly grooved. Endials a little
longer than wide. First costals of the same proportions as the radials.
Second costals smaller, proportionally shorter, and irregularly axillary ; one
of their upper faces short and giving off an arm, the other a row of distichnls,
which are followed by higher orders of brachials, and arms given oil at inter-
vals from opposite sides. Interbrnchials three at the regular sides, and four
at the anal side, the latter having three plates in the second row ogainst two
at the other sides. Ventral disk convex, the interambulacral spaces a little
depressed ; composed of moderately large, slightly convex plates. Arms
excentric.

Horizon and Loealif//. — Niagara group ; St. Paul, Ind.

Type in the collection of Wach«muth and Springer.

Remarks. — This species differs from M. lioemeri in the narrower and
less spreading base, in the proportions of the radials r.nJ costals, and in the
convexity of the plates.

304

THE CKLNOIDKA CAMEHATA OF NORTH AMKKICA.

MeloorinuB sequalis H. A. ^[h.lkk.

isijj. Adv. Shi'uU IMlh U('|i. (irol, »urv. lii(liiiiiii, p. IS, I'luto 6, Figs. 11 and 12.

A iiiotlenitely Hiiiall species. DoihiiI cup obpyrainidiil, decideilly peut-
iingiiliir lit tlio una bases, dooply sunken inteniidially. All plates of tlio
calyx heavy and tiiinid ; those of the dorsal cup covered with short ridj^es
at their margins, one to each side, the median portions of the plates
stnootli. Suture lines well marked. The radial appendages directed almost
horizontally.

IJasals nearly equal, longer than wide, the sides very little expanding.
Radials as long as the basals, a little wider than long. First costals hexa-
gonal, almost as large as the radials ; the S( cond smaller and irregularly
axillary, giving off at the shorter side an arndet, and at the longer the next
order of brachials. Rays free above the costals, and evidently composed of
a single row of plates, with arms given off at nlternato sides, Interradial
areas probably alike; the first interbrachial nearly as large as the adjoining
costal, followed by two and three smaller plates, of which the latter occupy
the arm regions. Plates of the tegmen very large, composed of onl^ two
rings, the upper supporting a massive anal tube, composed of tumid or nodose
plates.

JIurizon and Locdihj. — Niagara group, St. Paul, Ind.

Remarks. — This species resembles M. iwrvus in liaving simple free rays,
but differs from it distinctly in the form of the calyx, the greater convexity
of the plates, in liaving a much stronger anal tube, and the rays directed
horizontally.

Our description was made after Miller, and from fragmentary specimens in
our collection.

II. DOLATOCRTNITES.

SYMMETRY OP THE DORSAL CUP UNDISTURBED BY ANAL PLATES.

TECHNOCRINUS Hall.

1S.J0. 1I.4LL ; Palicnnt. New York, Vol. III., p. 139.

1870. Zittel; llirndb. dor Pidicnnt,, Vol. I., p. 372.

18S1. W. mid Sp. ; Revision Palteocr., Part II., p. 116 (Proceed. Acad. Nat. Sol. Pliiln., p. 290).

1889. S A. Mii.r.Eii ; N. Amor. Gcol. mid Pnlicoiit., p. 2S0.

Calyx large; symmetry perfectly pentahedral up to the arm base.",
except a slight irregularity in the basal cup. Basals four, somewhat un-

OCRIND^i;.

uqunl, arranged ns in M 'ncrimiH, 1 iir of tliP rndiiilH hep(|^o»«I. iho
anterior one liexiigoiial. Cu-.Uls two ; he llrni h vngonal, the secoud gpii'
emily pentagonal. Disticlmls 1x10, all Axillary. The finr Jilninr, u..<l
Honietiujen the Hecoiul, takes part in tlie calyx; 'tie »uccee<! .g ones being
arm [dates. Arms long, simple, straight, bisein, i ; fringed by good-sized
pinnules, which are in contact. Interbraehials three or foiir, but no inter-
disticlials. Structure of ventral disk and anus unknown. Column round ;
tapering.

Dls/r!hiilion. — The genus is known only from the Oriskany Sandstone of
Maryland.

Tijjjc of the genus : Technocrinits uplmilosva Hall.

JReinarks. — Tcchitncrlnm differs from Marlarriwrn and Mclocrinns in the
perfect pentamerous symmetry of its dorsal cup, and from the former in hav-
ing one instead of three to four distichala, no interdistichals, and the arms
arranged in an almost continuous series around the calyx ; while the orms of
Jfiiruwriniis are arraTiged in groups. It differs from Melncrimis in having sim-
j)le arms given off directly from the calyx, and not from its tubular extensions.

Technomnus striutus and T. sculptus Hall, were described from detached
basal plates.

Teohnoorinus splnulosus Hall.

Plate XXIL Fig. 3.

1859. Hall; Palicont. New York, Vol. III., p. 140, Plate 85, Figs. 1-lS.
1881. W. and 8p. i Revisiou PaliEOcr., Part II., p. 117.

Calyx subglobose, the arm bases slightly contracting. Plates of the
dorsal cup marked by a, central spine or node, surrounded by smaller
nodes, which vary in number among the plates. From the nodes two to
four parallel ridges pass out to the sides, and these are continued upon
adjoining plates. Near the arm bases the ri(^ges gradually disappear, and
the plates are marked only by a central spine.

Basals four, of medium size, forming a shallow basin with five sets of
four ridges, each set communicating with those upon the radials. Eadials
and costals nearly as wide as long, decreasing in size upwards ; the necond
costal but half the size of the first. Distichals one to each side of the cos-
tal axillaries. The first palmar enclosed in the calyx. Arms twenty, stout,
rounded ; composed at their bases of cuneate pieces, which interlock farther
up, and gradually become biserial. Interbraehials apparently four. All

•^

SU6

TIIK f HINOIUKA CAMKUATA OF NOHIU AMKUIt'A.

other parts of tliu calyx unknown. Culomn Mliglitly pi>ntMH;onaI, cuch altor-
natu joint provided with a node or sliort Hpinu at tlie margin.

lliirixna ami Luculilij. — Oriwiiany Hand,stono, Cuniljorland, Md.

Tiji)e in tlio Aniurican MuHuuni of Natural Ilitttory, Nuw Vurk.

TeohnooriQui Andrewti IIali..
I'luieXXJV.Fig.3.

1S50. II*ll ; I'liliri.iit, New York, Vol. Ill,, p IH, Pluto 86, Figl. 1-4.
18SI. W. uiiil Si'. ; llcvisioii I'ulndir , I'iiil 11., p. 117.

A rather large Bpecies. Calyx to tho nrin bosoH hemispherical ; platen
moderately convex, surrounded by Hcts of short marginal ridges paxsing in-
ward, three to four to each side of tho plato, and by small pits ali>ng tho
sutures; tho centre of the plates perfectly smooth. Ilasals wider than high.
Radials large, about as long as wide. First costuls of the form of the radi-
nis, but considerably smaller ; the second still smaller, narrower as well as
shorter. Dlstiehals one, axillary ; supporting in tho calyx two rather largo
palnuus, followed by several cuncate, interlocking free plates, and thef<e by
two rows of subquadrangular pieces, united by a sharply zig/ag suture.
Arms four to the ray, strong, flat, and of almost uniform width throughout.
Pinnules contiguous. Interbrachials four or five: 1, 2,1, 1, all compara-
tively large. Column round, large, tapering ; the joints rather long and
slightly rounded exteriorly.

Horizon and LocalUij. — Oriskany Sandstone, Cumberland, Md.

Type in the American Museum of Natural History, New York. The
species is described and figured from a cast made from tho natural mould in
tho rock.

ALLOCRINUS W. and Sp.

1880. W. niul Sp. ; Genl. Rep. Illinois, Vol. VIII., p. 200.

Calyx small ; the arms stout ; symmetry of dorsal cup equilateral.
Basals three, small, unequal — the left antero-lateral plate one half the
smaller — forming a di.sk, which is almost completely covered by the col-
umn. Eadiala large, much wider than the costals. Coatals two, rounded
like arm plates. Arms uniserial, strong, simple ; two to the ray, being
free from the second or third distichal. Interradial spaces composed of
two or three plates, of which the first is much the largest. Column
small, round ; axial canal narrow, pentangular.

■

Mi:i<(M UINII)-K.

n(»7

Dlstrihulinn, — Alhrrinux in rcHtricteil to Atiiorifu. Tt luildiii^'H to ii litllo
gronp of Crino'ulH \\\\\vt\\ in hpiiriiigly ri-pre-untt'il in tliin coiiiitry, lint of wliicli
ML'vi'riil gt'iicni with a iiimilK-r of Hpi'cioM art' known to liavo oxiwtftl ilnriiij,'
tilt' Uiiper Silurian puriod in Swi-den and Kngland.

Itnntirkx. — TliiM goiuiH IniM clone alliniticH witli Piitt/lwirimit and Puldfo-
I'lliniM. It dilTurH, liowcviT, fnun both of tlicm in tho form and t<i'/.c of the
variouH calyx platon, and in having iiniHcrial arinH. It idno n|)proachuM Clh-
trurrliuis, but thin ban a largo and [icrA'ctly ancdiyloHod banal dink.

AlloOlinUB typUl W. nnd Bp.

PlakXXIV.FujH. 7ii,h.

18sn. W. nml 8p. ; Ocol. Rqi. IlliiioK Vol. VIII., p. 207, I'lntc XIV., FiR. 7.

Below niedinm mzo. Calyx depressed, proportionally small, sharply
pentangular in outline, tho arm bases projecting, tho arms massivo and
proportionally stoutor than those of any otiior Crinoid ; the platos with-
out ornamentation. Rasals snuill, forming a llattcned disk, which is almost
covered by the column ; interbasal and l)a!<i-radial sutures indistinct. Hadials
large, abruptly curved, tho lower portions forming the rim of an inverted
shallow basin, tho upper half bent abruptly upward nnd forming together
with the plates above a shallow, spreading cup with straight sides. Costals
nnd fixed distichals short, curvvnl like arm plates, producing upon the sur-
face of the calyx strong, roi nded ridges, which insensibly pass into the free
arms. Arms ten, stout, uni rial, free above tho second plate; compo.sed of
transverse joints with parallel upper and lower faces. The arms much wider
midway than at either end, tapering considerably and uniformly toward tho
tips, but almost a.s much toward the calyx. Tnterradial spaces deeply de-
])ressed, composed of two plates vertically arrangei], of which the first is tho
Inrgor and nodose, and extends to the top of the costals ; while the other is
on a level with the fixed brachials, and forms, to some extent, a part of tho
ventral surface. Nothing is known of tho anal aperture and tho structure
of tho ventral disk. Colunm round, small ; axial canal pcntnngulnr.

Iliirixon and Localiti/. — Ningara group ; Wayne and Decatur Cos., Tenn.

Ti/2Ks in tho Worthen collection, Springfield, nnd that of Wachsmuth and
Springer.

Fjk

^^SH^I^

^-"^

308

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

Alloorinus Benedioti s. A. Milleu.

rUitc XXIV. Figs. Sa, h.

1891. S. A. Miller; Adv. Sheets Hlli Itip. Geiil. Surv. ludiium, p. 37, Plate 7, Fig. 1.

Closely resembling the preceding specie.^, but the dorsal cup n little
smaller and less sharply angular, the plates generally more convex, and
the arms not quite so stout. Dor.sal cup bowl-shaped, a third wider than
high, the lower end distinctly truncate, the sides convex, the plates elevated
and more or less nodose.

Basals forming an equilateral pentagonal disk, which has twice the diam-
eter of the coUnnn, and occupies the bottom of a shallow concavity ; inter-
basal sutures indistinct. Kadials large, curving gradually upwards, their
upper ends at right angles to the lower. Both costals together of about
the size of the radials, wider than long, the sides decidedly beveled and
forming a deep groove toward the interbrachials. First costals quadrangu-
lar, the second pentangular. Distichals one in the calyx, the others free.
Arms ten, .so far as observed, moderately heavy ; their plates quadrangular.
Interbrachials one, very large, elongate, and highly convex in the middle,
beveled around the margins. Structure of ventral disk unknown.

Horizon and Locality. — Niagara group ; St. Paul, Ind.

I i

CENTROCRINUS W. and Sp.

ISSl. TV. nud Sp. ; Revision Pakocr , Part II., p. 104 (Proceed. Aead. Nat. Sci. Pliila., p. 278).
Syu. AcHiiocriiius (in part) Lyon ; 1809, Trans. Ainer. I'liilos. Soc, p. 453.

Dorsal cup elongate, plates smooth. Ba.sals represented by a large
pentagonal disk, showing no traces of suture lines. Radials unusually
large, followed by two costals, which are proportionally very smtill. Dis-
tichals still smaller, taking the form of arm plates. Arm openings large,
directed outward. First interbrachial plates large, followed by two smaller
pieces. All other parts of the calyx unknown. Column very small.

Distrihution. — Represented, .so far as known, by a single species from
the Hamilton group of America. Ccntrocrimis tennesseensis Worthen, from
the Niagara group of Western Tennessee (Geol. Rep. Illinois, Vol. YIIL, p.
95, Plate 14, Fig. 1), has infrabasals, and is a totally different thing.

Memarks. — The name Ccntrocrimis was previou.sly proposed by the

MELOCRINIDiE.

309

Austins,* who recommended its application for certain species of riutjcniius
•with " central vaivate unobstrusive mouths, or mouths capable of beinjj
withdrawn into the visceral cup." Even substituting "anal opening" lor
mouth, there is no Platycrinoid to which the above delinition is applicable ;
besides the name has never been accepted by any writer, nor was it applied
to any particular species by Austin himself. Cmtrocrinus, as here delinod,
is allied to the Platycrinidoo in its anchylosed large basal disk and the small
size of its costals, but differs essentially in having two rows of interbrachials
within the limits of the dorsal cup. Lyon's figures show interbasal sutures,
but they cannot be seen in his specimens.

Centrocrinus pentaspinus (Lvo.\).
Plate XXV, Figs. 10a, b, c.

1869. Jc/inomimsjienlaspiiiiis — hms ; Trans. Amcr. Pliilos. Soc, Vol. XIII., p. 4.58, Plate 2fi, Figs, il

and (//.
18S1. Centrocrinm pentaspinus — Vf. und Sr.j Revision Pnteocr., Part II., ].. 101 (Proceed. Acad. Nat.

Sci. Philn., p. 279;.
Syn. Jclinofrinu.1 midlkornus Lyon ; Trans. Amor. Pliilos. Soc, Vol. XIII., ].. 4.55, Plate 20, Tis.

e; and Ccnlrocrinus mulliconius — W. and Sp. (Revision, Part II., p- lOu).

Dorsal cup as wide as high, subcylindrical, flat below, the sides nt right
ancles to the bottom. Plates without ornamentation, but the radial.^, and
sometimes the first interbrachials and first costals, armed with a sharp spine,
■while the other plates are merely convex.

Basal disk very large, forming a regular pentagon, whose surface is
covered by a sort of rounded collar, extending over the greater part of the
surface, leaving only the angles free. Eadials almost twice as laif-o as the
two costals together, the upper face much narrower than the lower. First
costals quadrangular, half the width of the radials, and less than half their
length; the second costals shorter than the first, pentagonal, with obtn.^e
upper angle. Distichals two, short, curved like arm plates; the npper ones
excavated to form the arm openings, which are large and arranged in groups
with wide interspaces. Interbrachials four; the first plate large, hexagonal,
rising to the top of the first costals, the lower angle deeply Avedgcd in be-
tween the radials; the two of the second range are followed by a small piece,
resting between the arm bases. Ventral disk, arms and anus unknown.
Column small ; axial canal apparently circular.

• Thomas Austin, and TLomas Austin, juu., 1843, Monogr. Rec. and Foss. Crin., p. G.

310

THE CRINOIDEA CA^IKRATA OF NORTH AMERICA,

Iluriziiii and LucaUti/. — Upper Hclderbcrg group ; Falls of the Ohio,
near Loui.sville, Ky.

I'iipc in the L} on collection at Jeffersonville, Ind.

Remarks. — Actinocrinus multicornus Lyon is undoubtedly a mere varia-
tion of this species. The addition of small spinous extensions upon the first
costals and first interbrachials is not a sufficient reason for specific distinction.

DOLATOCRINUS Iaon.

1Sj7. Lvon; GpoI. Rep. Kentucky, Vol. III., p. 482.
1877. S. A. Mii.LKR; Cat. Amer. Piiltcoz. Foss., p. 77.

1881. W. 1111(1 Sp. ; Revision Pnlicoer., Part II., p. 124 (Proceed. Acad. Nat. Sol. Pliila., p. 208).
Syn. OcffiormM — Hall; 1862, 15lh Hep. N. Y. State Cab. Nat. Hist., p. 137.

Calyx depressed. Dorsal cup flattened below, sometimes to the full
height of the costid-i ; the plates generally ornamented with radiating
ridges and nodes. Ventral disk but slightly elevated, surmounted by a
large, alino.st central tube ; the interambulacral spaces depressed. Basnls
anchylosed, the lines of union obliterated. Eadials large and hexagonal.
Costals two ; the first quadrangular, with convex upper and lower faces,
narrower than either radials or second costals, and wider than long; the
upper one pentangular. Distichals two to four in species with only two
primary arms ; but when there are additional bifurcations in the calyx there
is but one. Ambulacra! openings large, arranged in groups, with wide
interspaces, and directed upwards. Arms biserial, generally bifurcating.
Interbrachials rather numerous, there being generally three ranges. The two
proximal rows consist of a single plate each, of which the first is the largest
plate of the calyx, rising to the top of the lir.st distichals; the upper row
connecting insensibly with the interambulacral plates. The latter plates
consist in most of the species of a single row of from five to seven rather
large cuneate pieces — the smaller end directed downward — which, except
the three middle ones, are not in contact laterally throughout their full
length, their lower ends being slightly excavated, so as to leave narrow slit-
like openings between the plates, two to three to each side of the interradius,
or four to six to the whole area. Some species have two rows of interambu-
lacriil plates instead of one, four to six smaller ones being placed beneath the
others, and the upper margins of these plates are slightly pierced by the
lower ends of the slits. Above the interdistichal areas, there are rarely more
than two slits, and not exceeding four. In the dorsal cup, the arrangement

MELOCRINID^.

311

of the interrndinl plates is invariably the same at all sides, but at the anal
side the ventral disk has a few additional pieces, and the plates pierced by
tlie slits are shorter. The disk contains large orals, pushed anteriorly by
the stout, almost central anal tube, and it has well defined radial dome
plates of a first and second order. Ambulacra subtegminal. Column large,
round ; the sides covered in some of the species by large angular processes
or ribs ; axial canal very large and pentalobate.

Z>(s^/-i6M;ion. — Restricted to the Upper Helderberg and Hamilton groups
of America.

Ttii^e of the genus. — Dolatocrinns laciis Lyon.

Remarks. — The complete anchylosis of the basals, the large size of the
first interbrachial and its being followed by a single plate, the large anal
tube, and the slit-like openings at the sides of the arms, together with the
perfect symmetry of the dorsal cup, form excellent characters of this genus.

Lyon described the base as composed of live pieces, while Hall mentions
three basals, but the fact is that the sutures are not visible externally in the
specimens. Mr. Victor Lyon, however, sent us a specimen in which the
presence of three plates is indicated at the inner floor, while no suture
lines appear exteriorly.

The slit-like openings have not been noticed before. We regard them as
analogous to the respiratory pores of Batocrinus, from which, however, they
differ in number, form and arrangement.

Hall, in 1862, described several species of the type of Dolatocrimts under
Cacabocrimts, a catalogue name of Troost, and among them Cacahocriims
Troostl and C. lamellosus, of which we have been unable to get authentic
specimens. The descriptions are too general for specific identification.

1S37.
18S1.

Dolatoorinus lacus Lyon.
Flate XXVL Figs. Ga-c.

Lyon; Geol. Rep. Kentucky, Vol. .III., p. 48^., Plate 4, Figs. 2, 2(r-c.
W. and Sp. ; Revision Pnltrocr., Part IL, p. 126.

Calyx depressed hemispheric, flattened below, somewhat tumid around
the summit. Dorsal cup more than once and a half as wide as high ; the
basals and the lower half of the radials deeply incurved, and formed into an
inverted funnel-shaped concavity, which is wider than the column, the latter
touching only the bottom part. The upper half of the radials, and nearly

V, '"^

S12

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

.ar.'/..vj

the whole of the first costals, spread out horizontally; while the second
costals and disticlials turn straight upward. The ornamentation of the dor.-al
cup con8i.sls of two or three rows of parallel ridges, which pass out from the
middle of the plates — with or without interruption — to adjoining plates,
so as to form numerous concentric triangles. A more conspicuous ridge
passes up and down the rays. Another, equally prominent, connects the
radials laterally, and forms a pentagon around the basal concavity. The
radials, first co.stals and first interbrachials are each surmounted by a promi-
nent node, while the plates of the legmen are covered with small, granular
prominences.

Basals small, almost completely concealed by the column ; forming a
conspicuous cone at the inner floor of the calyx. Radials larger than first
and second costals together, their greatest width equal to their length ;
their upper lateral faces shorter than the lower. First costals once and
a half as wide as long, the upper and lower faces somewhat convex. Second
costals a little longer and wider than the first. Distichals 2 X 10 in the
calyx ; the lower one almost as large as the preceding axillary ; the others
small, and supporting the arms of which there are two to the ray. Arm
bases projecting ; the ambulacrsil openings large. First interbrachials as
large as the radiiils and first costals together; they rise to the height of the
first distichals, and are followed by a single much smaller plate in the second
row, and three still smaller ones above, which support three or four plates
in the disk. Orals and radial dome plates well defined, larger than the inter-
ambulacrals. Anal tube almost central. Column round ; the axial canal
large and pentalobate.

Horizon and Locality. — Hamilton group ; in the limestone bed above the
Black Slate ; Louisville, Ky.

Type in tht Lyon collection at Jeflersonville, Ind.

Dolatoorinus Marshi Lyon.
Plate XXVI. Figs, la, b, c, d.

18P.9. Ltos j Trniis. Amcr. Philos. Soc, Vol. XITI., p. 401, Plate 27, Figs. «,»!,» 2.
1S81. W. nnd Sp. ; ncvision Pnloeocr., Part II., p. 126.

Calyx of medium size, wider than high. Dorsal cup basin-shaped, the
bottom deeply excavated and truncated to near the top of the second
costals ; the sides gently curving upward to about a vertical position ; the

jielocrixid-t:.

813

nrm bases slightly projecting nnd lobed, giving to the cross-section nn
obtusely pentagonf.l outline. Ventnil disk low-pyramidal, the interauibu-
lacral spaces llat or slightly depressed, nnd the plates apparently without
ornamentation. In the dorsal cup the plates are traversed by a large num-
ber of very fine radiating ridges, passing from plate to plate, four to five
from each side, which are well defined near the outer margins of the plates,
but become more indistinct along the median portions. Interbrachial plates
a little convex, the plates of the rays from the margin of the basal concavity
to the middle of the second co^tals surmounted by keel-like, very conspicu-
ous protuberances, which rise from the lateral margins of the plates, at first
very gradually, but near the middle of the plates almost perpendicularly,
forming knife-like edges at the outer end. The ridges are continued upon
the distichals, but above the costals lose their knife-like character.

Basal disk small ; restricted to the lower part of the concavity, which is
completely filled by the upper end of the colunni. Radials a little larger
than the costals, their lateral sloping upper faces considerably shorter than
the corresponding lower. Distichals two — sometimes three — the upper
one short and lunate, supporting the primary arms, two to the ray. First
interbrachial larger than any of the other places, nearly as wide as long;
followed by a good sized single plate, and this by two ranges of three plates
each, which rest between the arm bases. In the tegmen there are two large
cuneiform plates to each interambulacral space, which are faced by two or
more smaller pieces with four slits. Two similar plates and two slits overlie
the interdistichal spaces. Orals large, pushed anteriorly. Kadial dome
plates quite conspicuous ; three of them resting within the re-entering angles
of the orals, the two others against the large anal tube.

Horizon and Locality. — Upper Helderberg group ; Falls of the Ohio, near
Louisville, Ky.

Type in the Lyon collection, Jeffersonville, Ind.

Remarks. — Lyon described the basals as "horizontally disposed," and
" not concealed in the pit." We conclude from his type specimen that he
mistook the extended outer edges of the top stem joint for the margin of the
basal disk, and its nucleus for the column. Another specimen in the Lyon
collection shows the inner floor of the basal disk, which appears to be
tripartite.

./...^ /y-'^'^'f

^ /.^.: -i /- ^

314

THE CRIXOIDEA CAMERATA OF NORTH AMERICA.

»l

I '

< •:

Dolatoorinus Marshi, var. hamiltonensis W. and Si>.
Plate XXV. Fkjs.'M,h.

A form very similar to D. Mamhi occurs in the Hamilton group, which
we distinguish from the typical Ibrm as variety huiniltoncims. The basal con-
cavity is shallower and narrower, the radial ridges knife-like, and occupy the
median line of the plates instead of being keel-shaped and rising gradually
from the outer margins of the plates. The ventral disk is considerably
lower, and but slightly convex ; the orals smdiler, the posterior one, which
is very short, is placed so as to form at the anterior side the base of the anal
tube. All plates of the disk covered by several well defined tubercles.

Ilorkon caul Loculiti/. — Hamilton group. Bear grass quarries, Louis-
ville, Ky,

Type in the collection of Mr. Victor W. Lvon, Jeffersonville, Ind.

Dolatoorinus Lyoni w. and Sr. (nov. sppc).
Plate XXV. Fiijs. 6a, h., c, d.

Calyx rather large, considerably wider than high. Dorsal cup more than
twice as wide as high ; the basal portions deeply impressed, forming a broad
funnel-shaped cavity which includes one half the radials. The plates above
the lirst costals curve gradually upwards, and the two upper rows stand at
right angles to the truncated lower part of the calyx. Ventral disk low-
pyramidal, slightly grooved toward the arm bases ; the plates flat, covered
with numerous small pustules. The plates of the dorsal cup are grotesquely
ornaiuented with a variety of prominences and depressions ; some of them
elevat'.'d into sharp, very conspicuous, transversely rounded nodes, others
sharply pointed ; and from all of them somewhat irregular, subangular ridges
pass out to the margins of the plates, connecting with similar ridges from
adjoining plates. The plates of the rays have no nodes, and but few ridges
proceed upwards ; those directed laterally form n well defined pentagon
around the basal concavity. In the upper part of the calyx the nodes cover
the greater part of the plates, and the ridges are merely indicated at their
outer margins.

Basals small, restricted to the bottom part of the cavity. Eadials nearly
as large as the two costals together. First costals quadrangular, narrower
than the radials ; the second pentangular, supporting upon one side an axil-

■rii

MKLOCRINIDyE.

315

lary diHtichal followed by 3 X 2 paltnars and two anna, upon the oilier three
fixed di.stielmls, which support one arm. There are three primary arms, two
and one, to the ray; two of the simple arms facing the anal intcrradiiis.
Arm openings directed obliquely upwards, less projecting and smaller than
usual in the genus. Interbrachials : 1, 1, 3, 4 ; the first large, rather angular
below, broadly truncate above, the upper sides a little wider than the lower ;
the second almost as large as the first, with a long transverse node. The
three plates of the thiid row much smaller and provided with elongate nodes.
The plates of the fourth row, which occupy the arm regions, are small and
highly convex, their upper faces pierced by the lower part of the slits. The
interambulacral plates consist of five large cuncate plates, of which the three
middle ones are larger than the others ; the sides of the outer ones excavated
to form the slits, which are quite large in this species. The anal intcrradius
has a few additional plates in the disk, which connect with the anal tube.
Interdistichals four to the arm region.s, arranged in two rows, followed by
three cuneate interambulacral plates, with two slits, while there are four slits
above the interbrachial spaces. Orals large, all of similar form and .size,
surrounded by good sized radial dome plates of a first, second, and third
order. Anal tube almost central, its base formed of rather large convex
plates.

Horizon and Localili/. — Upper Helderberg group ; Clark Co., Ind.

Ti/pcs in the collection of Victor W. Lyon, Jeft'ersonville, Ind.

Remarks. — This .species is readily distingui.shed from all others of this
genus known to us by the grotesque st3'le of its ornamentation.

A/'i' 1 1

DolatoorinuB canadensis Whiteaves.
Plate XXV.Fifjs. 7a, h.

1SS7. WiiiTEAVESj Gcol. mid Nat. Illst. Surv. Caimda; Contrib. to Can. rnlwont., Vol. I., p. 99, Plate 12,
figs. 3, 3(7.

Of the type of DoMocrinus Marsld, but with a different arm foi-mula.
Calyx small, much wider than high. Dorsal cup broadly and shallowlj-
b.asin-shaped, slightly depressed along the radials, and more conspicuously at
the basals. "Ventral disk lower than the dorsal cup ; hemispherical ; the
central portions slightly tumid. The ornamentation of the dorsal cup con-
sists of numerous parallel ridges, passing out to the sides of the plates, and
meeting those of adjoining ones. The rays along their median lines followed

316

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

/^.C/ A

d\ fl ^^/ •

by broiul, keel-like processes, which form into a knot in tlic centre of the
radiiils lunl .second co'ttal.s. Anotiier prominent ridge runs from the lower
margins of the first interbrachiuls to tlie middle of the plates, where it forms
a rather sharp node, from which two brandies proceed to the upper lateral
margins. The smaller ridges, of which there are three to four to each side,
are marginal, extending but a short distance into the plates.

Basals small, perfectly anchylo.sed, surrounded by a circular ridge, and
entirely covered by the column. Radials larger than the costals, hexagonal,
wider than long, widest above the middle and not visible from a side view.
h ^ First costals short, quadrangular; the second considerably wider, a little
. longer and axillary, giving oflf to one side an axillary distichal, which sup-
ports a small palmar at each side, and this an arm. The opposite distichal
gives off a single arm from the second plate, thus making throe primary arms

to the ray. Arm bases projecting, giving to the calyx, as seen from above,

a pentagonal outline. Structure of the arms unknown. Interbrachials : 1,1,
3; the first large; the second much wider than high; the middle plate of the
third row compamtively largo ; the two at the sides as long, but narrower.
Ventral disk composed of but few large plates, which arc covered with several
minute pustules of irregular arrangement ; the intcrambulacral spaces
dejjressed, consisting generally of only two plates, wliiidi abut against the
orals. Tlierc are no interdistichals. Orals and ambulacral plates arranged
ns in the preceding species. Anus subcentral.

Jlor'aon and Loca/iti/. — Hamilton group; near Thedford, Ontario.

Ti/pe in the Canada Survey Museum at Ottawa.

Jicmar/iii. — It is barely possible that Hall's Cacahocrinus Troosd, from
Western New York, is identical with this species, but it is described with
four primary arms instead of three.

Dolatoorinus triadactylus Barris.
Plate XXVI. Figs 4a-d.

18S1. Babbis; Procped. Davcnp. Acad. Nat. Sciences, Vol. IV., Pinto 2, figs. 5-7.
1885. W. and Sp. ; llcvision Palajocr., Part III., p. 105.

Of medium size. Cal^'x depre.ssed, a little wider tlian high. Dorsal cup
broadly basin-shaped ; the lower portions truncate to near the top of the
first costals, then curving rapidly upwards, a little constricted below the arm
bases ; the basals moderately excavated, and the margin of the cavity

MKLOC'BINIDili:.

317

surrounded by a circular ridgo ; tho nrtn bnsos slightly projecting. Surfiicc
covered by numerous angular ridges, wliieli radiate from centre to centre of
tho plates, producing various geometrical figures. The ridges connecting
the radials form a pentagon around the basal pit, which is radially disposed
and of which tho sides support five triangles, each one enclosing a smaller
one. The outer triangles, together with the pentagon, fonn a live-rayed
star, and tho spaces between the rays of this star are also formed into tri-
angles, which are followed by other triangles above.

Basals small, resting completely within the columnar depression. Radials
and costals of eqnal height, but the first costal narrower than the second.
The latter supports at one side an axillary distichal, followed by two small
palmnrs and two arms, and at the opposite side by two successive distichnls and
a single arm, making three arms to tho ray. Arms stout, biserial, not bifur-
cating at the lower ends ; their upper parts unknown. Arm joints short,
with parallel faces. First interbrachial largo, supporting a smaller, sub-
quadrangular plate, and three plates in the third row, which in turn are
followed by five cuneate plates, which extend above tho level of the arm
regions. At the four regular sides, the throe middle ones of those plates are
considerably larger than the outer ones, and touch the orals ; at the anal
side they are followed by a few additional plates, which abut against the
anal tube. Interdistichals .small, consisting of three pieces, succeeded by
two interambniacral plates forming two slits. The number of slits at tho
interradial spaces cannot be ascertained from the specimens. Ventral disk
.slightly tumid ; the interambniacral spaces depressed, the plates almost fiat,
the orals and radial dome plates, which are somewhat larger, covered with
small but sharp nodes. Anus snbcentral. Column round, with crenulated
edges ; axillary canal pentangular.

If'irizoii mid Loriill/i/. — Hamilton group ; Alpena, Mich.

Ti/j)es in the Museum of the Davenport Academy of Sciences.

V y''' '<^

^ J

■"'V "

. .y ,

Dolatocrinus glyptus (TT.vi.i.).
Plaie XXVI. Figs. 2a, b.

1802. Ca.aljnrriiiun glyptus — \\.K\.\.; 15lli Hop. N. Y. Stntc Cab. Nnt. Ilist., p. liO.
1S81. ])ii!iili>''i-iiitt.i fili/iitiix — \V. niid Sn. ; Revision Piilirncr., I'nrf II., p. 125.

Syii. Cimihofriiiim filj/plii«, vnr. intrrnifiHus IIam, ; l^Sl, 15tli Keg. Rep. N. Y. State Cab. TCat.
Hist., p. lU.' '

Syn. Duliilocriniis ornalm Meek; 1871, Proceed. Acad. Nat. Sci. PLUa., p. 57.

318

THE CRINOIDEA CAMERATA OF NOUTH AMERICA.

P' .

.... t'.

(A '"'•

; 'I

■; ',1

Larger timii any of the prccediiij^ species. Ciilyx »le[)resse(I-yiobose,
soinewliat llattoneil to near the top of tlie radials; rapidly curving above, so
that tiie walls of the dorsal cup near the arm bases arc parallel to those of
the opposite side. Plates ornamented by interrupted ridges or lines of
small nodes, some of them radiating to the angles of the plates, others to the
sides ; those passing fiom the basal pit to the nnn bases the strongest and
almost continuous, rising to angular nodes in the centre of eacli plate. First
interbrachial provided with a strong central tubercle, and the ridges pro-
ceeding from the radials to the first disticlmls more prominent than the
others. Suture linos slightly channeled.

Basal disk comparatively large, the upper angles projecting l)oyond the
column, the median portions concave, and the cavity surrounded by a cir-
cular rim. Radials considerably wider than the costals, and also wider than
long. First costals twice as wide as long, the lower faces distinctly convex,
the upper a little concave. Second costals longer than the first, slightly
increasing in w'''h upwards, the sloping upper faces obtusely angular.
Distichals 2X2; the first equal to two thirds the size of the axillary costal ;
the two of the second row not more than half the size of the first, and those
of the second row separated by an interdistichal. Palmors two, short, lunate,
supporting the two primary arms. First interbrachial almost as large as any
two other plates of the calyx, and nearly as wide as long ; followed by
a comparatively large hexagonal plate, which supports three others ; the
two at the sides elongate and smaller than the middle one. Ventral disk
depressed-pyramidal. Anal tube subcentral, rising gradually from the disk.

Horizon and Locality. — Hamilton group ; near Pavilion, Genessee Co.,
N. Y., and Columbus, 0.

Tf/pe in the American Museum of Natural History, New York.

Remarks. — We regard Cacahocrinus gh/jitm, var. intermedins, described
by Hall, and Dolatocrinus ornatas Meek, as mere variations of D. glyptun, the
specimons only differing a little in the ornamentation. In the typical
D. (jhiptus, the ridged upon ;he plates are not continuou.s, but consist of
irregular series of elongate nod'js; while in the specimens of Z). (jJijptits, var.
intcrmedius they are generally not interrupted. D. ornatus was described by
Meek as coming from the Hamilton group of New York.

MELOCRINIIU:.

819

DoIatoorinuB liratuB (IIali). —

riatcXXVJ. Flij.J.

ISfli. Ciidilmi'riHua lirii/iit — llvl.i, ; l.")tli lli'|p. N. Y. Slal.: Cub. Nul. lli«l , p. l:)9.
1^?«1. Jhliiiiii'intun lifdlm — W. mill S|i. ; Ilcihiim I'lilii'ijcr., I'lirt II., |i. \ifi.

Sjii. t'lifabucriima liiutHi, var. mullilira — IIaI.1. ; l.'illi l(<|i. N. V. filalc C'lil). Nut. Hisl., p. 139.

Very closely resembling D. t/h/phin, nnd probably a mere viiricty of tlint
Hpecies. The speciiuens referred to the latter by Hall are nliorter nnd tlieir
bnMul portions more deiJre.-^Hed, but this niny possibly be due to pressure.
They agree in the Ibrni and arrangement of the plates, and both havf two
primary urms to the my, a depreM.sed ventral disk, ridges along the ambu-
lacra, and nn almost central anal tube. The only perceptible diflerence is in
the style of ornamentation. The ridges, which in J). ijIiijUuh are more or
less interrupted, are continuous in J), lintfns. It has, besides, large ridges
radiating from the centre of the plates to each of tlieir angles, and three to
live smaller ridges pa.ssing out to the sides, where they join with similar
ridges from adjacent plates. The plates of the ventral disk are densely
crowded with large and small prominences, similar to those found in certain
species of Amp/ioracrlnKfi.

Horizon anil LocaJitij. — The same as the preceding species.

Tjpc in the New York State Cabinet of Natural History at Albany.

Dolatoorinus ioosidactylus av. and Si-. (nov. speo.).
riatc XXV I . Fitjs. Sa-d.

A large and greatly depressed species of the type of D. ffl'//>fus, but
readily distingui-shed by having four instead of two primary arms to the ray.
When not crushed, the calyx to the base of the anal tube only about four
fifths as high as wide, but it appears to be still shorter in the usual preserva-
tion. Dorsal cup twice as high as the tegmen, broadly cup-shaped, ilattened
to the top of the costals, and the basals formed into a funnel-slinped cavity,
surrounded by a circular ridge. The median lines along the plates of the
rays to the bases of the arms elevated into prominent ridges, nnd the middle
of each radial and costal crowned by a small central node. The nodes are
directed longitudinally ; they are in some specimens r|uite conspicuous, while
the ridges are almost obsolete ; in others, however, the ridges are almost ns
high ns the nodes. Smaller ridges, or more properly speaking, rows of elon-

/.^ '•

. .Iff/

/. ■ >'

' \

820

TIIK CHINOIDKA CAMKIIATA Ol' NOHTII AMKIUCA.

I I

'. 0-'/ ;■

.21

^1 < ■^ •'» I/-

giitu noduN, railiiito U'm\ tiuiir tlio iiiiilillo of tliu mdiiilM iind coHtalH to (lie
turgor iiiturbriicliiiiirt, tlio latter hiiviiig guiicM-iilly four hucIi ridgCH to ouch
«ido of tlie pliitu, urraiigcd paralli'l. Toward tlio iipptT part of tlio dorwil
cup tlie ridj,'ox almost di;mi)pL'ar, and tlio plates iiro nimply tumid.

Hasal disk dcpri'ssi-d fiiiiiR'l-sli.ipi'd ; tliu outer rim on a level with the
rudials; pi'rforatod by u lurgo, i)eiitalohato canal with nharp re-entering
nngloH, which extend deeply inward. Ihidialft larger than the costals, their
length equal to the width at the lower end; the truncated upper faces con-
cave; the sloping upper faces nuieh shorter than the sloping lower. First
costaln Mul)(iu'ulrangular, narvovver than theradials; upper and lower sides
convex. Second costal-* very little wiiler, hut considerahly longer and pen-
tangular. Distichuls 1X10; all axillary; almost ns large us tho Hccoiid
cotttuls. Pulnuirs much smaller, the two lower ones, which arc short and
lunate, incorporated into the oalyx. Arm openings arranged in groups ;
large ; directed ol)li(|uely upwanls. Primary arms twenty, Interl)rachial
spaces wide, the plates arranged ; 1, 1, 2; the first larger than the radials;
the second almost ns largo ns tho rust costnis, suhqiiadrnngular ; the two of
the third row much smaller. Uetween the nrm openings are three to five
minute pieces, which are followed by two large elongate plates in the teg-
men, and several additional plates at the anal side. There are four slits to
each interradial space, and the saiiie number to each interdistichal space.
Ventral disk low-heiuispherieal, surmounted by n medium sized almost cen-
tral tube; the course of the ambulacra marked by an clevntion, tho inter-
ambulacral spaces depiossed, especially neiu' the outer margin ; tho plates
completely covered with small pustules of even size. Orals and ambulacral
plates us usual in the genus. Column round, the joints with slightly waving
edges, and rapidly increasing in size downwards; the nodal joints projecting.

Horizon and Locallfij. — Hamilton group ; Louisville, Ky.

Types in the collodion of Wachsmuth and Springer, and Victor W. Lyon.

liemarks. — This s])ecies bears some resemblance to " Cocahocriiiiis "
hoHcUustis Hall ; but differs considerably in the form and size of the basal
depression, which in the latter species, according to Hall, is large, sub-
circular, and embraces the basals and one third of the radial plates. It also
occurs at a different geological horizon.

Mi'.i.ocuiNih.i;.

321

Dolatoorinui exoavatui w. im.i sv. (mv. Bpoc).
I'laf. A' AT. Fi>j. /, and I'lat, WW I. Fl./x. T in„l S.

A very lnrj(o HpocicH. Doi'kiiI cup »ihiiIIow-biinin hIhuhmI, llin-o timoH nn
wido M higli ; lliu bottom llatt(MUMl to tlio t()|) of tlio ooxtals; tlio niiIch
convex, rnpiilly curvinj^ iipwiinlM, II littlo constrictcil iit tlic arm Imson; f|ii>
radiiils formud into a deep, nliarply pentangular, rimnel-Nliii[ii>d pit, which
ponotratoH tho calyx almost to tlio heigiit of the arm ro;>ionH. Siirfacu of
platen — except those in tho j)it — covered with parallel riilgen, radiating
from tho centre of the plates to their sides, whore they meet with wimilar
ridges from ailjoining [)lates. In addition to these ridges there are keel-liko
projections following the radials and costals, which grow more conspicuous
downward, and at about the top of the radials are produced into a tubercle,
which projects into the funnel-shaped pit, nnd gives its npi)er margin a
slightly stellate outline. Occasionally the carinate ridges arc continued to
the higher brachials, but. as a rule, they becoino obsolete above the second
costals. Suture lines slightly grooved.

Basals elongate ; forming together with the radials a highly elevated
inverted cone with a large pentalobatc canal. Radials large, once and a half
ns long as wide ; four fifths of tho plates taking part in tho pit, tlic other
fifth bending al)ruptly outward ; upper sloping faces short ; the lower faces
eqiud to one half the greatest width of the plates. First costals small, twice
ns wido as long, tluir upper and lower faces convex. Second costals wider
than long and slightly wider than the first. Distichals four; tho first os
largo as the two costals together. Arnis two to the ray, about equidistant.
First interbrachial slightly curving, larger than the radials and first costals
together, elongate, widest across the middle of tho plate ; angular at both
er. Is; the lower end bending inward so as to form a part of the pit. There
nre two largo plates in tho second row, three smaller ones in the third, and
these arc succeeded by a row of six elongate pieces in the ventral disk, and
two additional larger plates which abut against the orals. Interdistichals
one or two in the dorsal cup, followed by five or six small pieces in tho
togmen, and a larger one between the secondary radial dome plates. Slits
six to each interradial space, and four to each interdistichal one. Ventral
disk depres.sed, slightly tumid ; the interambulacral spaces flattened, and
sometimes a little depressed, producing indistinct ridges along the ambulacra.

WICJM WWtl—

"T^WFayr .""mmmp^

322

THE CKIXOIDEA CAMEIIATA OF XOUTJI AMEIUCA.

I^'i!

..... n...^ ^f-

/ -

,ch

fi- /:>'

: I

Orals large ; the posterior one small and lunate, owing to the almost central
position of the large anal tube.

Horizon and Zoailltij. — Upper Ileldcrborg ; Clink Co., Ind,

T;/j)cs in the collection of Victor W. Lyon.

RcmarJcs. — Differing from all othei known species of this genus in the
great size of the calyx, tlie form and depth of the basal pit, in having two
secondary interbrachial.^, and in the number of the slits. The specimen on
Plate XXVI., Fig. 7, exhibiting the inner Loor of the disk, is very interest-
ing as showing the counuunication of the slits with the inner cavity.

DolatOOrinuS major AV. and Sp. (nov. spec).
Plate XXV. Fiff.S.

A very large .species, in general form resembling the preceding, but with
a shallow ba.sal depression, four arms to the ray, and without surface orna-
mentation. Dorsal cup depre.ssed-bowl-shaped, almost three times as wide as
high, flattened below ; the radials and part of the costals stretched out hori-
zontally ; the basals forming a shallow concavity surrounded by a thickened
rim; the sides gently bending upwards and becoming parallel at the top of
the first distichals. The plates are smooth, with the exception of a small
rounded node upon the two costals ; that of the first costal occupying the
upper end of the plate, that of the second the median part. Radials compar-
atively small, con.siderably wider than long ; the upper and lower lateral
faces almost equal ; the lower margin thickened and forming a rim around
the basal concavity. First costal as large as the radials ; the upper face
decidedly convex, and the lateral ones slightly, but the lower face straight.
Second costal larger than the first, broadly pentangular. Distichals 1 X 10 ;
large ; axillary ; supporting two good sized fixed palmars, and these the
free arms. Arms twenty, arranged at almost equal distances around the
calyx. Interbracbial spaces somewhat depres.sed at their lower ends, and
slightly receding between the arm bases ; the first plate large, its upper half
considerably wider than the lower half, its upper face truncate and somewhat
concave. The plate of the second row is approximately as large as the first
costals, but higher than wide and hexagonal ; the lower lateral faces parallel,
the upper lateral ones sloping. There are three plates in the third row, and
others above. Interdistichals one. Structure of the ventral disk unknown.

Horizon and Locality. — Upper Helderberg group ; Falls of the Ohio.

Type in the collection of Victor W. Lyon.

Will

"&i

:' i

BIELOCRIXID.E.

323

Dolatoorinus speoiosus (Hall).
Plate XXV. Figs. 4a, b.

1802. Cacalocriiiiia speeiosus — Hall ; IStli Rop. N. Y. Slate Cab. Xiit. Ilist. , p. V67,
1881. Ihlatocriiius speciuniis — W. and Sp. ; lU'visioii I'alii'ncr., p. 12G.

Of the type of D. major, but smaller; the dorsal cup proportionally
hiylicr, and provided with a somewhat deeper basal pit; the radials instead
of being stretched out horizontally, gradually slope toward the basal con-
cavity, without actually forming a part of it. It has but two distichals, and
two arms to the ray instead of four ; arranged in pairs with wide interspaces.
Cress-section below the arm regions subpontangular. Plates apparently
without ornainentiition, their surfaces slightly convex; tUe median line of
the plates following the rays gradually rising into a keel-like projection or
carina, which passes up to the bases of the arms. This carina is higher upon
the radials and costals, and thickened at the middle of each plate, where it
is formed into a conspicuous elongate node ; the node of the fust costals
more prominent than the others.

Basals small, forming a shallow inverted basin, which is completely filled
by the column. Radials larger than the costals, and about as wide as long.
The first costal narrower and shorter than the second, and quadrangular ;
the second obtusely angular above. Distichals 2 X 10, comparatively large ;
followed by a lunate arm plate. Arm openings two to the ray, directed
obliquely upwards, and those of the same ray packed closely together. First
interbrachial almost as wide as long, with an obtuse lower angle, and its
upper face broadly truncated ; the second about half the size of the first, its
lateral faces parallel. The latter supports three plates, two upon its sloping
lateral sides, and one upon the truncated upper face, which are followed by
a row of interambulacral pieces. The interdistichal spaces contain two
plates. Ventral disk slightly convex, each side containing four interambu-
lacral plates, two of them larger and cuneate, touching the orals, the two
smaller ones abutting against the secondary radial dome plates. The
posterior oral is deeply wedged in between the four others, and considerably
shorter. Anus almost central.

Horizon and Locality. — Upper Ilelderberg group ; Western New York.

The specimen figured is from the collection of Wachsmuth and Springer.

A-

e.-.-^^ ^'^

324

tup: crinoidea camerata of north America.

Dolatocrinus tuberoulatus w. and Sp. (nov. spec).
Plate XXV. Fig. 3.

Of the type of D. (jlyjitus Hall, but dillering in the style of ornamenta-
tion. Dorsal cup not twice as wide as high ; subglobose, slightly depressed
from the middle of the radials downward ; central concavity small, elliptical,
formed by the basals only, and completely filled by the upjier column joints.
The radials, costals and first interbrachials are each elevated into a large,
very conspicuous tubercle, and the tubercles are connected by well-marked
ridges. There are generally four parallel ridges from the interradial to the
radial nodes, and the same number between the radials and first costals,
which form five sets of four triangles around the coluum at some distance
from it; those of tlie same set concentric. The costals are connected with
the first interbrachial by two ridges, while there is but one ridge, but more
prominent, between the distichals. Other ridges connect the distichals with
the higher interbrachials. Basal disk small, almost completely hidden by
the column, and surrounded by a prominent circular rim with small nodes
interradially disposed. Radials large, almost as long as wide, much larger
than the first costals; the second costals higher and wider than the first.
Distichals apparently two, each one provided with a short node. First inter-
brachial smaller than usual in this genus ; followed by a quadrangular plate
in the .second row, and three smaller plates above. Nothing is known of
ventral disk and arms.

Horizon and Lociditij. — Hamilton group ; Clark Co., Ind.

Ti/pe in the collection of Mr. Victor W. Lyon.

STEREOCRINUS Barris.

1S7S. BvnnTs; Proceed. D.iTciiport Acad. Nat. Sciences, Vol. II., p. 282.

1881. \V. and Sp. ; Uevision Palicoer. Part II., p. 126 (Proceed. Acad. Nat. Sciences, Pbila., p. 300).

1885. B.^iiiiis; Proceed. Davenport .\oad. Nat. Sciences, A'ol. IV., p. 103.

1889. S. A Miller; North Amcr. Geol. and Palieont., p. 283.

In general form, ornamentation, and the arrangement of plates resem-
bling Doladtcrlnus, but having one costal instead of two, and a tripartite
base. Dorsal cup depressed, truncate below. Basal disk small, pentagonal ;
composed of three pieces, of which the suture lines are generally visible.
Radials and costals nearly of equal size ; the former hexagonal, the latter
pentagonal and axillary. Distichals two or three, supporting the arms.

■ 1

i •-]

MELOCRINIDiE.

325

Arm openings, so far a^ observed, two to the ray ; arms biserial. Interradial
spaces wide, containing three ranges of plates in the dorsal cup ; the first
and second range composed of one plate each ; the third of two or three ;
followed by large cuneate plates in the disk. Ventral disk rather flat, the
interambulacral spaces depressed, containing one or more slit-like openings
at each side of the arms. Ambulacra subtegminal, but their course indicated
by elevations upon the disk. Orals large and arranged as in Bolatucrimis.
Anus subcentral, apparently at the upper end of a tube. Colunm round ;
central canal large and pentalobate.

Distfihution. — This genus has been observed only in Michigan and Iowa.
The typical species came from the Hamilton group ; but we have in our
collectioi. a specimen apparently of another species, from rocks considered
to be Upper Ilelderberg, of Waterloo, Iowa; it is not, however, sufficiently
perfect for description.

Rtereooriaus triangulatus Bakris.
Plate XXV. Figs. 8a, b.

1S78. BvBRis; Proceed. Davenport Acad. Nat. Sciences, Vol. II., p. 2B1, Plate 11, Figs. 1, 2.
1881. W. and Sp. ; Revision Palococr., Part II., p. 127.

A rather large species. Dorsal cup shallow-basin shaped, twice as wide
as high ; the truncate lower part formed by the basals, radlals, the larger
half of the costals, and a large part of the first interbrachials; the lateral walls
of opposite sides nearly parallel ; the extreme upper end slightly constricted,
and the interradial spaces a little depressed between the arm bases. Orna-
mentation re-^embling that of Dnlatocnnus trkdactijlus, the surface being
covered by similar sets of parallel ridges, but less prominent. Only one of
each set passes from centre to centre of the plates, the others being inter-
rupted. By means of these ridges the whole surface of the dorsal cup is
divided up into numerous triangles, each one enclosing one or two smaller
ones. There are five such sets of triangles around the basals, three to each
set, and similar triangles are formed in the upper part of the calyx.

Basals largely projecting beyond the column ; central canal large, penta-
lobate. Radials a little larger than the costals, all wider than long. Dis-
tichals 2 X 10 ; the first rather large ; the second short, lunate. Arm bases
projecting, arranged in pairs. Arms two to the ray; their structure un-
known. First intcrbrachial a little larger than the radials ; the second about
half the size of the first, followed by two or three plates in the third row,

•msFm '■'■vmmm:;

326

THE CRIXOIDKA CAMEllATA OF NORTH AMERICA.

1! i

and a number of small plates in the ventral disk. Disk dcpressed-hemi-
splioric ; tiic interanibulacrul spaces nearly on a level with the ambulacra ;
all tiic plates s]i<;htly convex. Anal tube large at the base, and almost
central.

Horizon and Localiti/. — Hamilton group ; Davenport, Iowa.

7}/j)fs in the Museum of the Davenport Academy of Sciences.

lioiun-ks. — The small specimen which Barris described as variety "lira-
tus," is in our opinion not sufficiently distinct for separation, and, it ><eems to
us, the ditferences given are readily explained by individual growth.

Stereoorinus Barrisi w. and Si-. (nov. spec).
Plate XXV. Figs. Da, h.

Svn. Slereocriiiiis triunijidutus Bauris (in part).

Of medium size. Calyx more than once and a half as wide as high,
flattened to the top of the radials, and .slightly depressed at the basals ; the
sides from the middle of the costals rising vertically ; lobed at the arm
bases. Ventral disk short, slightly tumid, the interambulacral spaces deeply
depressed so that the ambulacral regions are conspicuously elevated. Plates
of the dorsal cup covered by similar .sets of triangles as in the preceding
species, but the ridges forming them more prominent, and there is a node in
the centre of each plate ; suture lines difficult to see. The column is sur-
roun<led by a strong circular ridge.

Basal disk projecting beyond the column. Radials and costals nearly
equal in size, the former hexagonal, the others heptagonal. Distichals three
in the calyx ; the first a third the size of the costals ; the .second and third
extremely short, the latter facing laterally. First interbrachial very large,
the two of the second row much smaller. Ambulacral openings large, elon-
gate. Respiratory pores four to each interradius, and two above the inter-
distichal spaces. Orals rather large, slightly tumid, pushed to the anterior;
the posterior one resting against the b.ise of the anal tube, which is almost
central. The plateu covering the food grooves small and tuberculiform ; the
interambulacral ones somewhat larger and almost flat. Column small, round;
the axial canal large and pentalobate.

Ilorizim and Localiti/. — Hamilton group ; Alpena, Mich.

Tffpes in the Museum of the Davenport Academy of Sciences, and in the
collection of Wachsmuth and Springer.

Eemarks, — This species has close affinities with the preceding one, and

1 I

MELOCRIXIU^E.

327

Barris apparently rogardot! the two forms as representing the same species.
How iver, on examining a largo nnmber of specimens of both types, wo find
a separation necessary. In »S'. Batrtsi the basal disk is small, extending but
slightly beyond the column, and the facet for the reception of the column is
surrounded by a heavy, circular rim. In S. trkuKjidatus the disk is qnite
large, the top stem joint occupying less than half its diameter, and it has no
rim around the fticet. The interambulacral spaces of .S'. Barrisi are much
more depressed, the ambulr.cra more abruptly protruding, the orals larger,
and the interambulacral plates flat and less numerous.

HADROCRINUS Lvon.

1809. Lyon ; Trniis. Amcr. Philos. Soc, Vol. XIII., p. 445.

1881. W. niul Si'. ; Proceed. Acad. Nat. Sci. Pliihi , p. 396 (Revision, Part II., p. 222).

1889. S. A. Miller; N. A. Geol. and PaliBonl., p. 252.

Calyx very large ; the dorsal cnp saucer-shaped, its lower portions con-
cave. Basals small, completely covered by the column and placed at the
bottom of the cavity ; they are closely anchylosed, and their suture lines are
visible only upon the inner floor. Radials pentangular, the lower half bent
inward, the upper stretched outward. Costals one, pentagoniil. Distichals
and palmarsaro always represented in the calyx, and sometimes post-palmars;
each order by two to four successive plates of the same size as tiie costals ;
the uppermost plate excavated to form a facet, which is directed laterally,
and supports the arms. Interbrachials variable in number and irregular in
their arrangement, as large as the adjoining brachials. The anal side may,
or may not have an additional plate in the second row. Interdistichals one
to three, longitudirially arranged, as large as the interbrachitils. Structure
of ventral disk, arms and anus unknown. Column very large near the calyx
(Lyon), round, tapering rapidly, and giving off cirri ; axial canal circular at
the top of the column, but pentalobate farther down.

Distribution. — Only known from the Upper Ilelderberg group.

Type of the genus. — Iladrocn'mis cUscks Lyon.

Ecinarls. — The specimens are all imperfect, and no satisfactory definition
of the genus can be given. It is allied to Stcrcocriniis in having but one
costal to the ray, but differs essentially in the number and arrangement of
the interbrachials, and in having .sometimes an anal plate. L3on's descrip-
tion of the column needs confirmation, being made from detached pieces.
His JT. jymtagomis is defined from a single ring of plates, and the species
cannot be recognized.

"'(wmur-.

Wt: '■'-■ r^yfc«^7v ;>»-*jiiWWl-*-'^

328

THE CRIXOIDKA CAMERATA OF NORTH AMERICA.

Hadrocrinus discus Lvon.
Plate XXIV., Fiij. 1.

isno. Lyon ; Trans. Amcr. I'liilos. Soc, Vol. Xlll., p. MS, Tlatc 26, flg. a.
1S81. W. null Sp. j Revision I'lik'ocr., I'lirt 11., |). Hi.

A very large species. Dorsal cup flat-snucer-shnpcd, tlie rndials forming
a sliallow concavity, of which the basala occupy the bottom, the radials the
sides. From the top of the radials to the second distichals the plates are
directed horizontally, and from there they proceed slightly upward to near
the arm bases, where they attain again a horizontal jiosition. Plates moder-
ately heavy, apparently without ornamentation; slightly concave, the median
space having a shallow circular pit, sometimes two being placed clo.se to-
gether. Ba.sals not visible in the specimens, and judging from the space
assigned to them, they were unusually small. Radials and costals small ni
proportion ; the former a little the larger, their lower faces one half the
width of the upper; the upper sloping faces larger than the corresponding
lower ones. Second costals almost regularly pentagonal. Distichals 2 X 10,
larger than the radials, considerably longer than wide ; the first hexagonal,
the second pentagonal and axillary. Palmars 4 X 20 in the calyx, the two
lower ones as large as the distichals and of a similar form, the two upper
much shorter and slightly curved for the reception of the arms. Inter-
brachials nine or more, irregularly arranged, all nearly equal and as large as
the distichals. The anal interradius has three plates in the second row, which
are narrower than the two of the other sides. Interdistichals three, longi-
tudinally arranged, elongate, hexagonal, as large as adjoining brachials.
Structure of arms and ventral disk unknown. Columnar facet large, beauti-
fully .striated.

Horizon and Locality. — Upper Helderberg group ; Falls of the Ohio,
near Louisville, Ky.

Types in the Lyon collection.

Hadrocrinus plenissimus Lvov.
Plate XXIV., Fi(js. 2a, h.

186!). Lyon ; Tmn?. Aiiier. Pliil.is. Soc, Vol. XIII., p. Wa, riak 20, Figs, i 1-3.
18S1. W. nnd Sp. j Revision Pulii-ocr., Part II., p. 222.

The specimens are fragmentary and crushed, so as to leave some doubt
as to the actual form and size of the calyx, except that it was depressed and

MELOCRINIDiE.

329

extrt'iuuly large. Lower portions of the dorMnl cup to the top of the costnls
deeply concave, forming a liirge inverted cup, which extends deeply into
the cavity of the calyx ; the succeeding plates spreading almost horizontally
with a slight upward curvature. The entire surface covered with somewhat
flattened ridges passing from near the centre of the plates to their sides,
where they meet the ridges of adjoining plates. There are from two to four
ridges to each side, but two of them are frequently united in the specimens,
so as to form one larger ridge with a broader surface.

Basals closely united, forming a small inverted cone, which occupies the
bottom of the dor.sal cavity and is completely hidden by the column. Tlio
inner or ventral surface of the basals is convex, decidedly wider than the
outer or dorsal surface, and marked by five well defined angular ridges,
radial in position, from which small protuberances pass out and enter the
axial canal, producing the j italobate outline. Between these ridges and
around the axial canal, there are five shallow circular depressions occupying
two thirds of the basnis, which probably lodged the quinquelocular or dorsnl
organ. Radials large, somewhat variable in size, about as wide as long; the
lower faces wider than the i,j)per ; the upper sloping faces less than one hidf
the length of the lower ones. Costals pentangular, very much smaller than
the radials, sometimes barely one third their size. First interbrachial rising
to the top of the costals, the two of the second row elongate and but little
smaller; they are followed by other rows, but their arrangement, as well
as that of *\ie higher brachials, cannot be accurately determined from the
specimens.

Horizon and Locality. — Upper Helderberg group ; near Jeflersonville,
Ind.

Ti/pes in the Lyon collection.

Remarls. — Lyon describes this species as having 2X2" secondary
radials," and several more "orders of radials" above, each order represented
by two plates, and he mentions seven to eight " interradials " and two " in-
teraxillaries." He also suggested from small detached pieces, which may
possibly belong to a very different form, that this species hnd from eighty to
one hundred arms ; all of which has yet to be confirmed by more perfect
specimens.

CALYPTOCRINID^.

Monocyclic. Lowku bhachials and interuiiaciiials foiimino an important part
OP TUB dorsal cup. Uadials in contact all around. Arms kestino in
compartments, formed uy partitions attacued to the teumen. Plates of the
calyx limited to a definite number. Dorsal cup, except the base, pekfectly
pentamerous.

AiKilytiis of the Genera,

Basal* 4.

1. Pnrtitlonsextendintjfothet'ipaoftheuvms El'CAi.YPTOCRlNrs.

L'. Puvtitiuna enclusinij (inly the lower jioHiona of the anus Callicuinus,

GtolnijienI and (ieor/raphkal Distribution.
Number of known species.

(Open figures indicate American ; those marked ( ), European)

FORMATIOX.

CAI.TrTOCIllSID*.

General.

Aniericiui.

ApiH'oxiinate

Kuropoan

Equivalents.

Eucalyptocrinus.

Callicrinus.

Devonian.

Eifel.

Upper Silurian.

Niagara.

Wenlock.
Gotland.

17 (10)

4 (8)

Total species 40 | ,jL

n (11)

4 (S)

Remarks. — Roemer proposerl the family name " Eucnlyptocrinida9 "
(Lethoea Geognos. (Ausg. 3), 1855, p. 229), which Angelin in 1878 changed
to Calyptocrinidffi. Tlie latter name was accepted by Zittel, who errone-
ously included with it Li/riocrimm^ViW, which is a dicyclic Crinoid.

The Calyptocrinidne agree substantially with the Dolatocrinites .section of
the Melocrinidae in the construction of the dorsal cup, but their basals occupy
the bottom of a deep concavity, and they are remarkable for having the

[

CALYFrOCRINIDvE.

881

■

Fio. 15. Fiti. 14. Fio. in.

Fio. II', showing plntcs of t]io dorsiil cup, the arms and their partitions.

Fio. 15, the cul;x in a side view.

FlQ. 10, llie partition walls u( KiiraU/ptocrinua rosaeeus (after Sehiiltzc).

i:=hasnls; 72 =: Railials ; /=:costaIs; //=(li!>ticlml9 ; iir ^ inlorhrachials ; iV ^ intcrdisticlials
/^ = arnis; (/•/'= intcrradial partitions; iV//'= intcnlistichal partitions; /i := llrst ring of plates of the
trgnicn ; 13 = the second ring ; (S ^ the third ring ; and /4 = t\ie fonrth or npper ring of the tcgnien,

plates imited to a certain number. The dorsal cup is perfectly pentamerous,
the rays being separated by intorbrnchialH of uniform number and size, and
their main divisions by a single large interdistichal. Still more important
from a classificatory point of view is the structure of the ventral di.^k, which
differs from that of any other known Crinoid, recent or fossil. It is com-
po.sed of only four rings of largo plates of irregular form, of which the two
lower ones completely cover the disk ambulacra, which rre subtegminal, the
upper ones forming a long neck or tube enclosing a narrow canal. Not
only do the plates of the disk, like those of the do".sal cup, consist of a defi-
nite number, but tliey are throughout tliis family unusually large, and their
arrangement does not appear to be in accordance with the pentamerous

88a

THK t'KINOlDKA CAMKIIATA OF NOttTII AJIKIIK'A.

Hyinmotry of tliu Crinoiils generully. Aiiotlicr most rctnnrknhio feature,
wliieli MupiiiatuM tliiis family diHtinctly from all other Ciimuratii, is tlie coiii-
partiiU'UtM eiicioHing the aniis, which tire formed by processes or imrtitioiis
attached to the outer si''" of the disk, and uro supported by the iiiter-
brachials and interdistichals.

The family was restricted to the Upper Silurian, with the exception of
a single species found in the lower Dovonian of the Kifel. It was the lead-
ing family ' f its epoch in the number of species discovereil, there being
twenty-one from America, and eighteen from England and Sweden, but only-
two genera.

EUCALYPTOCRINUS (ioiDK.

1820. Goi.Dfims; I'etrcf. (ii'iniiin., Vol. I , p. iU, mid 183S, Nova AoU Leop. Vol. XIX., 1, p. 335.

bll. MOli.kii; Ui'il. Akiid. <l. Wi.xsciiscli., p. 210.

18 U. ll.ALi, i I'liliiMmt. N. York, Vol. II., p. -207.

13W. ItoKMKiij Klii'in. Url)cr)?iiiigs),'rl) , p. (i'J, iiiiil 1855, Lctlmctt Oeogn. (Ausg. 3), p. 257, nnd 1800,

Silur. Fiiuim Wrst. 'IVini., p. 48.
1853. lie. K()Ni.N( K ami I.kiion ; Ucclicr. sur les Criiioides du Terr. Carboiiifcrc de la Bflgiiiut, p. 7h willi

diiigriiiii.
1857. Pktet; Truilu ile I'alcoiitologie, Vol. IV., p. 307.
1^0:2. DnjAKUi.N mid Hii'K; Hist. Nut. des Zoopli. Deliiii., p. 115.
180:!. H.\l.[.i Trails. Albany Inst., Vol. IV., ji. li)7.
18iill. Sl'iiultzk; Monogr. Kcliiii. Kill. Kidk., p. UO.
1S7'<. AxoKLl.v; leonnpr. Crin. Slice, p. 10.

187'J. I1.VU.; 28tli \U-\). New York Slate .\liis. Nat. Hist., (Kd. II ), p. 141.
1879. ZiTTKi,; llandb. dcr ralii'ontolosii', Vol. I, p. 370.
1885. QiKx.sTKDT ; Haiidl). d. IVtrcfactrnkniide lAiisg. 3), ]>. "JfiS.

1S8J. W. and Sp. : Kevision I'alii'ocr., Part III., p. 127 i I'locced. Acad. Nnt. 8ci. Pliila., p. 349).
18S9. S. A. .Mii.i,Kii; N. AiiiiT. (ii'ol. and I'alii-ont., p. 2 Hi.

Sp\. J/i//Mii/iocri/ii4.i I'liii.Lirs, ls:!9; Miiicliisuii's Sdur. System, p. 072, I'latc 17, i'ig. 3 ; ZittuI,

1879 J Angelin, 1878 j S. A. Miller, 18S0.

Calyx with the arms attached more or less ovate ; without the arms
resembling a wine bottle with concave bottom and slender neck ; the neck
surrounded by ten longitudinal partitions closed from above, and forming
ten niches or compartments into which the arms, in pairs, and to their full
length, exactly fit. Dorsal cup composed of four bnsals, five radials, 2X5
costals, 2x10 distichals, 1 X 20 palmars, 3X5 interbrachials, and 1X5 inter-
distichals. The basals, which form an inverted funnel-shnped cup, are not
visible from a side view, and the calyx rests upon the edges of the inflected
lower portions of the radials; the plates varying in size, the anterior one
larger than the rest. Axiid canal five-rayed, the anterior basal pierced by
two of its rays. First costals quadrangular, the second pentangular unless
the upper angle is truncated by the interdistichal. First distichals larger

41^

i!i

(■•!<

CALYlTOf RlNIDiK.

833

^1^

than the Kccotid. The firnt piilinarH Hiipport the nrniH; thoy are whort, trun-
cated at the upper face, and are provided with Huiall niiiwit' jjlntes and
fo8.sto. Fir.>*t interbracliialM generally the largest i)lateH ol' the dornal cup,
more (hiui twice an large a« the two above. The two latter are of about the
same form and nize, and are in contact laterally to their full length. Tiiey
rine womo distance beyond the top ol' the palniars in scjuare or tapering trun-
cate projections, and jointly form a support lor the interradial partitions.
The interdistichab rest either within notches formed by tiio distiehals, or
upon the trinicato upper face of the second costals. They resendde in form
the combined upper intorbrachial.s, rise like these to the height of the third
arm plates^ and support in a similar maimer to the interbrachials a partition
woU npon their truncate upper faces. The projections between the arm
sockets give to the specimens a very nnirked aspect, and serve as a reliable
guide for generic identification in case the ventral structures of the calyx
are not preserved ; in that condition they look like cogs of a wheel.

The toginen, or part above the dorsal cup, consists of four rings of plates
of peculiar structure. The lower ring is composed of five elongate inter-
radial pieces which rest npon the i)rojecting upper faces of the interbrachials,
and five plates of similar form and size supported by the interdistiehals.
The middle portions of the ten plates extend outward and upward in form of
knife-like winged proces,ses, of which the upper end rises to near the fourth
row of plates, overlapping the plates of the second and third rows, to the
outer faces of which they are attached by suture. Interposed between thefe
plates are ten small trigonal pieces, arranged in such a manner that a plate
supported by an interbrachial, and one supported by an interdistichal, always
meet laterally over the top of one of the triangular pieces. The latter plates,
which are somewhat thickened at their median lines, form a .sort of subpar-
titions between the arms of the various pairs, without being visible when the
arms are intact. Their e<lge8 at both sides, and also tho.se of the larger
plates, are pierced by the ambulacral or arm openings, which are well
defined in this genus, and enter the calyx between the two plates. The
second and third rings, which form the tubular prolongation of the calyx,
are composed of four plates eacli ; the fourth ring consists of ten pieces,
which meet around the summit. The plates of the second ring slope
upwards ; two of them are wider, and alternate with the other two ; the
two narrower plates are longer, and angular at the top, the others truncate.
United they form an inverted funnel, the margin surrounded by ten protu-

1- i

834

TIIK ( UIN<HI)KA CAMKUATA OF NOUTII AMKHK A.

boraiiooH, wliicli represent ton lonKihuliniil ridgen upon the outer Rurfacc.
Tlio riilgeN meet tlio upwiird pmluiigationM uf the platen of the firat ring,
with which they are HUturally cuuueeted and tbrni a nolid wall ; while the
alternate groovcM form the inner ,iart of the Jiirlien. The platoM of the third
ring are narrower than those of the xocond, and like them provided with ten
longitudinal clevationi^, which are overlapped hy certain projeetioUH paHHing
down from the platoH of the fourtli ring. The platoH of the upper ring are
quite remarkal)lo as forming the upper part of the anal tid)e, the top of the
crown, and at the «ttme time the encasement for the tips of the arniH. They
are constructed upon a plan similar to that of the large plates of the first
ring, and, like them, have wing like extensions, which from a ventral aspect
present a well tlefined decagonal star, with n vacant space at the Nummit.
The lower ends of these wings meet the upper ends of the wings rf the first
ring, HO as to form, together with the projecting surfaces upon the plates of
the two middle rings, ten continuous walls, which extend from the edges of
the dorsal cup to the top of the crown. The open space between them
represents the end of the anal canal, which is closed variously by from five
to ten small irregular pieces surrounding tiie anal opening, and sometimes by
additional larger plates. The anus in i-omo species is drawn out to a tube
of great length, extending far beyond the limits of the arms, but more fre-
quently rises but little above the top of the compartments. Arms heavy,
arranged in pairs, each pair occupying one of the ten compartments, their
backs almost even with the edges of the partitions, their lateral faces abut-
ting against the sides. They have a wide ventral furrow, and are composed
from the third or fourth plate tip of two rows of short, transverse pieces,
which are .so closely united l>y suture, that the arms must have moved cii
masse upon the calyx. Pinnules long and closely folded. The visceral
cavity is formed by the plates of the dorsal cup and the two lower rings of
plates of the disk ; the plates of the two upper rings, whicli form the neck-
like prolongation, being, properly speaking, plates of the anal tube. The
ambulacra, on entering the calyx, follow the grooves at the inner floor, and
meet near the top of the second ring. Column moderately large, generally
round ; composed of rather long joints with pentapetalons axin! canal. It
has no lateral cirri, but branches at the end into hundreds of little rootlets.

Dlstrihut'inn. — A leading form of the Upper Silurian, and well repre-
sented in this country as well as in Europe. A .single species is known from
the Devonian : Encalyptomnus rosaceiis from the Eifel of Germany, the t^pe
of the genus.

CALYlTOdUMDvE.

335

lifmurkH. — Kitidlt/pforriniix wiih oriH:iniiny doncrihcd Uy CJoldfiiMK iin lniv-
iiig iiu HtuiM ; and I'liiltiim, wliu diHcuvurud iiiiutliur HpucivM with tliu Mtum
iittiiclicd, pi'U|io.<«fd fur tliiM tliu guiiiiH //i/pitnthorriniin. Aii^^cliii mid /itttil,
who iiciu'|)tcd IMiillipK' gomiM, doMCiihi- itn hiixo iih Iukm det'iily rntiiud-NhaiH'd,
thu aiiiil tubu art cxtoiidiii}^ boyuiid the tip.<i of thu uiiiih, and tlii! partition
walls uiicloHing thu ariiiH aH huiiig coiiNtriictud principally of unu |)iuco.
Nuithur onu ofthoHo I'hariicti'rH Im cotiMtaiit, and wo c-aniiot regard (hu two
furinM aH diutinet gunuriually. That tliu anal ttibu riMus ahovu the iiriiiM Im uf
vury litlli* Htriictnral value, if wu admit that thu iiuck-liku prolongation
troin tlio disk rupreMuiit« ii part of that tiibo. Tho earlier writern deMcriho
tlio riulials ns haMaU. Iloeinur diftcovcrud tho true baHo in 1H4!}, but ho
HuppoHud it waH quini|iiu-partito, and mo did do Kuninok and fje Hon. Mall in
1S03 found that it cotiHiHtcd of but four plates, and tluH wkh contirnicd by
Hubsefjiiunt authors.

Knriih/jitiirrliuis is a most porjloxing goniiH, owing to tho peculiar xtriic-
tiiro of its v( itral ]i)i>rt, which v as apparently not correctly understood by
Hall. lie de^-;ribed the partition walls as interbrachialH; while in fact they are
not separate plates, but tho outer proccxses from tho plates of tho disk and
tube, respectively, a sort of compound structure for which, we adopt the name
'•partition walls." The uventy pi. , m fonmng tho lower ring of the disk we
regard as largo interambulacrni p' 's meeting over the ambulacra ; but as
to the relations of the plates ol t!io .-ocond ring we are somewhat in doubt.
Wo have suggested in Il.Msion, Part III.; .-. 132, that they probably repre-
sented four of the or is, a.' ' that the fifth was pushed upward, and consti-
tutes a part of the anal tube. This seems not impro- iM » if we consider that
the posterior oral in all Palmozoic Crinoids is puslic. more or less out of
place by the anus ; and it may bo expected that this was tho case to a high
degree in a genus in which the anal tube is lorgo and strictly central.

Miller's Ei(c(tliip(orrinus elli/i(iriis is too young a specimen to determine its
specific relations. A similar specimen from Rochester, N. Y., is figured by us
on Plato LXXXIII., Fig. 7.

Eucah/ptucrinns tmncusew, E. rhilUpni, E. conicus, E. nnnhfilJa, E, aiensus,
E. gibhoms, E. Iceris, nnd E. Goldfiissi, all of Troost, are mere catalogue names.
E. arw".'!' •• McChesney is a Si/ihniiocriims, and E. cormitun, E. crmvaius,
both desoiibed by Hall, and E. rami/er of Eoemer, have been referred by us
to CalUcnnus.

'^-^rmir .

•

330 TIIK CUINOIDEA CAMERATA OF NORTH AMERICA.

Euoalyptoorinus coelatus (Haix).
Plate LXXXin. Fhjx. 5, 0, 7.

1843. Geol. Rep. 4tli Distr. N. York, p. 113, Fig. 1, niiil I'liln-init. N. Y., p. ilO, I'lntc- 17, Figs, 4ff, b, e, <i.
1885. W. mill Sp. (ill |)art) ; IlcviMii)ii I'iiIiviht., I'lirl III., p. 1.1.''.

Not Eiiciili/iilocnMiin err/alun Hall, 18()."), Tniiis, Allinny lust., p. C?<i (Abslr., p. 38), and SOlli Krp.

N. Y. M.ilc Ciil). Nftt. Hist , pp. 341 t(i 3:!'.) (soeoml rd., pp. 3f.;t-3(>+), mid iiStli Hep., p. 142,

riiilo IC), Fif,'s. 1-10, mill riute 11), V\\;a. 1-3; iiUo lllli Ann. Oral. Hep. liiilinim, p. 274, Pliite

l.'i, V'\K. 1, i'latc 10, Figs. 1-10, I'lntc 19, Figs. 1-3, iilt of wliicli wc refer to EucalfptoeriHW

KImli S. A. Miller.
Nor Knciiljf/>/ucriiiua ctr/dlHt RoEMKH ; Siliir. Fniiim West. Tciiii., p. 48, Pliite 4, Figs. .'J(i-c=:

E. vnittif'uxitx.
S;n (?) Kucnlifptnrriiius {IIifimHthorriiiiis) ilenriix Hall, \'^\fi (not Miiroliison, 1S39) ; Geol. Hep.

4lli Distr. N. York, p. 113, Figs. ?-3, mid 1S52, I'lilwonl. N. York, Vol. II., p. 207, Plate 47,

Figs. 1-3, mid Plate 8.5, Fig. 7.
Syn. Kuealj/plocriiiun pttpHlosHs Hall; I'lilieont. N. York, Vol. II., p. 211, Plate 47, Figs. 5a, b.

or medium size. Length of crown compared with the grcnteat widtli at
the arm bases as 3 to 1, and witli the height of the dorsal cup as 3 to 2.
The Clip subturbinate, uniformly spreading from the middle of the radials to
the arm bases, the bottom part somewhat rounded. The plates of the cup
densely crowded with small pustules of uniform size, and similar pustules, or
small nodes, cover the outer edges of the partition walls to half their height ;
the upper part being marked by indistinct transverse ridges.

Basal concavity small, completely filled by the upper part of the column.
Radials large, wider than long, very slightly inflected, their lower ends thi'-k-
ened by a round, wart-like projection, which is devoid of ornamentation ; the
sloping upper faces short; the upper face concave. First costals wider tiian
long, the sides all convex, the upper face narrower than the lower. Second
costiils the size of the first, but pentangular. First distichals smaller than
the costals ; the second smaller than the first. Plates supporting the arms
small and irregularly qiiadrangidar. First iuterbrachial very large, longer
than wide, and tapering downward ; the two succeeding ones together almost
as large as the first ; they rise to a level with the third arm joints, are wider
at the bottom than at the top, and unite by a vertical suture. The interdis-
tichals rarely touch the axill.iry costals ; thov are twice ns long as wide, and
one third narrower tlian both upper interlirachiids together. Partition walls
almost as thick at the upper end as at the lower, and distinctly rounded on
the back. Arms tapering upward to fully one half their greatest width.
The four proximal arm plates single and somewhat longer than the others ;
the two succeeding ones cuneate, and those above arranged in two series,
which deeply interlock. The aims are covered with transverse rows of elon-

CALYPTOCRINID^E.

337

gate nodes. Anus at llie end of a small tube, rising 4 to 5 mm. above the
tips of the arms. Ventral part of the calyx not visible In any of tiie speci-
mens. Column round, the nodal joints very long and rounded at the outer
margins, the younger joints short and narrow.

IlorUon and Localiti/. — Niagara group ; Lockport and Rochester, N. Y.

Tifpc specimen in American Museum of Natural History, New York.

lientarh. — It is probable that the specimens which Hall referred to
Eiirah//>/ocrintis dironts Phillips, arc identical with this species. They cer-
tainly differ es.sentially from the English species (Plate LXXXII., Fig. 15),
which is proportionally shorter and stouter, the plates heavier and more con-
vex, the partition walls thinner, the anal tube stronger, and the column
obscurely pentangular instead of round.

The Waldron specimens with ornamented plates, which Hall identified
with this species, have been referred by us to Euml/jptocrinus Elrodi Miller.

Euoalyptocrinus tuberoulatus Millku axi> Dvku.
Plate LXXXIII. Figs. 8, .9, 10.

1878. MilXEHBiid Dvkb; Joiim. Cinciii. Soc. Nnt. Hist., Vol. I., p. 3fi, I'liitc 2, Figs. 9, 9(7.
1885. W. 1111(1 Si'. ; Kevi.sidii I'lilimcr., I'mt III., p. I'M.

Svn. Eiiriilyitlorriiim miirulis KiNofEiiEiKi ; IS'JO, .\111ml3 N. Y. Acad. Sei., Vol. V., ]>. 305, Plate
3, Fig. 3.

In its general form rcsemltling the preceding species, but diflfering some-
what in the proportions of the plates. Dorsal cup obconical, nearly as high
as wide, sides slightly convex, the lower end moderately truncated. Plates
a little elevated and covered by numerous tubercles of various size, larger
ones being interspersed between smaller ones; the suture lines distinctly
grooved. Columnar concavity narrow, its depth less than the width ; the
ba.sals completely covered by the upper end of the column.

Radiiils considerably longer than wide, rapidly tapering downward,
rounded at tiie bottom ; the lower end inflected to meet the bii,«als ; the
lower face very narrow, equal to one third the width of the upper, which is
rather deeply concave ; the sloping upper fares short. First costtds longer
than wide, narrowest at the upper end. Second costals wider than the first,
pentangular or hexangular. First distichals from one third to one half
smaller than the costals ; the second barely one third the size of the first ;
the arm-bearing palmars very much smaller and triangular. First inter-
brachials elongate, once and a half as long as wide, and nearly as large

•''^"VUfm.ir

338

TIIK CRINOIDEA CAiMERATA OF NORTH AMERICA.

as the liidiiils; thuy are widest next to tlie intercostal sutures, tapering to
both ends ; the lower lateral faces convex, and longer than any of the
others; the upper faces meeting the interbracliials of the second order. The
two latter plates combined are but little smaller than the lower one, their
tips rising conspicuously above the arm facets, and very little truncated.
Interdistichals much smaller than the corresponding interbracliials, their
lower ends touching the costals or resting between the upper sloping
faces of the distichals. The remaining parts of the species are not shown
in the specimens, but it may be suggested from the condition of the inter-
bracliials and interdistichals that the partition walls were unusually thin.

llorizun and Lwality. — Niagara group ; Waldron and Ilartsville, Ind.,
Lockport, N. Y., and Racine, Wis.

Tijpcs in the Museum of Comparative Zoology.

Jii'iu((r/,-s. — Miller and Dyer, in their specific description, after giving
the structure of the brachials, and stating that the first interbracliials are
" nine or ten-sided," continue as follows : " This description applies to the
two ton-sided interradials; the other three have only nine sides, as shown
by Plate 2, Fig. 9, and differ in supporting one supraradial instead of two."
Even if this were true, which is not the ca.se, it would have no specific sig-
nificance, but would only indicate an abnormal condition of that specimen.
By giving the specimen some additional cleaning, wo disclosed two distichals
in every ray, all supporting two extremely small pahnars, as shown by our
figure (Plate LXXXIII., Fig. 0). The peculiarity that some of the inter-
bracliials are nine-sided, is caused by the distichals, which in three of the
rays loan over to one side, so that one of them docs not touch the intorbrnch-
ials. In Miller and Dyer's second type. Fig. On on the same plate, which
wc also reproduce (Plate LXXXIII., Fig. 8), the respective plates are all
ten-sided.

We must regard Ewahipincrlnns viurah's Ringucborg as specifically iden-
tical with E. tiihircu/atits, until better specimens are found. Of Ringiub(Mg'.s
type, which we had for comparison, only the dorsal cup is preserved, ami this
is so badly crushed as to give no idea of its actual form. It is quite possible
that the base is somewhat broader than in Miller and Dyer's types, that the
plates generally are a little more convex, and the tubercles upon the plates
somewhat less proniinont. but the proportions of the plates are substantially
the same. Shnilar \ ariations may be expected in the limits of any species.

CALYITOCRINIDvE.

339

Euoalyptoorinus Elrodi s. a. ^Iiller.

(Revised W. and Sr.).
Plate LXXXI. Fuja. 7a, b, 8, 9, 10, 11, 12, 13.

ISOl. S. A. Mti.i.Rn; Ad. Sheets 17lli Kep. Geol. Surv. ludinim, p. 40, I'late 7, Figs. 9, 10.

%pi. Eiiiiili/ptoeriiiiis enlalut Hali,, ISCa (not ISi;!) I Trans. All). Insl., p. 2i() (Abstr., p. 32) ;

iiiiil (r) ;iOtli Uep. N. Y. Stale Cal). Niil. lli>t., y. ;W1 (ivvisctl cililion, p. 'MYA), and 2Stli Ucp.,

p. 142, riiile 10, Fifjs. 1-10, and I'lal.' 19, Fi(,'s. 1-3; al.so lllli Ann. Geol. Kcii. Indiana, p. 271,

IMalc 10, r ,. 1-10, and I'lalc 19, Figs. 1-:!.
Sjn. Eurul^iilwriiim subi/totuaua S. A. .M1LI.EB, 1S91, Adv. Sliects 17lli Kop. Geol. Shft. Ind., p. ;i7,

Pinto 7, 1 ig 3.

Usually a little larger than E. cwlatus, Hhorter in proportion, and not
attenuate at the poles. General form from subglobose to ovate, the base
inoilenitoly excavated for the reception of the column. Dor-al cup a little
shorter than the height of the partition walls enclosing the arms. The
plates of the dorsal cup, a.s well as the arms, and also the outer edges of the
partition walls, marked by numerous round or elongate nodes, often two or
three of them conlluent and forming straight or vermicidar ridges trans-
verse!}' or longitudinally arranged. The nodes upon the arms are in longi- '
tudinal rows, there being generally two rows in the upper part of the arms,
and four at the lower end.

Basal concavity small and shallow for the genus, the plates completely
hidden by the column, forming a short cone at the inner floor. Radials mod-
erately large, the lower ends curving abruptly inward, the remaining parts
outward and slightly upward, the lateral faces rapidly tapering, the sloping
upper faces short, and the upper face concave. First costals wider than long,
the sides convex ; the second hexagonal, the upper angle truncated by the
interdistichals. First distichals once and a Iialf as large as the second, and
the latter more than twice as large as the fixed palmars, which are subtri-
gonal. First interbrachial very large, the middle part almost as wide as long,
the upper end broadly trimcated by the interbrachials of the second row-
The two latter plates together are longer than wide, having the greatest
width at one third their height, whence they gradually .slant to the top,
which is truncate. The interdistichals are of a similar form, but one third
smaller than the two upper interbrachials, and rise, like them, considerably
above the level of the arm bases, each supporting also a partition. The
outer faces of the partitions are fully twice as wide at the lower end as at the
upper, and are slightly grooved. Arms gradually tapering upwards, quite

340

THE CRINOIDEA CAMERATA OF NORTH AMERICA.

f !

narrow at the extreniitioH, composed of very short pieces ; the three or four
proxinml onea simple, the upper riitiier deeply interlocking. Ventral disii
minua tlie partitions comparatively high, owing to the plates of the fust row
which are unusually large ; the plates of the second row are shallow funnel-
shaped, and those of the third shorter and very heavy. The plates of the
fourth row, which form the npper end of the tube, as well as of the com-
partments, enclose six or eight moderately large plates, and these again
a little short cone of eight or ten irregular pieces, which decrease in size
inward, and close the anus more or less tightly.

IlorUon and Locality. — Niagara group; Waldron and Ilartsville, Ind.,
and Chicago, Ills.

TyjKs in the State Cabinet of Natural History at Albany.

Jicviarfis. — The name Eucali/plocrinus Elrudi was proposed by Miller for
a specimen from Ilartsville, Ind., in which the nodes upon the surface are
exceedingly regular, and not in part confluent as usually in this species,
agreeing in other respects with the specimens from Waldron, which Hall
erroneously referred to E. ccelatits. The latter species, as represented at
Lock port and Rociiester, N. Y., its typical localities, is much more elongate
than the specimens from Indiana ; the dorsal cup is higher and obconical, the
radials longer and more nodose at the lower end, the partition walls thinner,
their outer edges convex instead of concave, and there is a small tube rising
above the walls of the compartments. Whether imder these circumstances
it is propc ; to accept for the typical form Miller's name E. Elrodi, which he
separated from it on account of slight modifications in the ornamentation,
may be questioned ; but we propo.se to do so to avoid further synouomy.
We therefore include in this species not only Miller's special form, but also
the specimens from Waldron and Ilartsville, figured by Hall under E. cwla/iis,
and also Miller's E. sithf/Io/Mnus, which latter we regard an immature form
of this species.

Euoalyptoorinus omatus Hall.
Plate LXXXII. Fig. 10.

1807. Hall; 20lh Rep. N. Y. Stole Cab. Niit. Hist., p. 329, Pliite 11, Figs. 4 ami 5.
1S85. W. ii!id Sp. ; Revision I'iilicocr., I'art HI., p. 134.

The dorsal cup, the only part known of this species, was descril)ed from
internal casts and gutta percha impressions, taken in the natural moidd of
the exterior. It is depressed, as wide as high, the radials directed hori-

CALYFrOCRIMIXE.

341

zontnlly, except their extreme lower ends, wliieh take part in the basal
concavity. CostaLs, first distichals and first inturbrachials curving rapidly
upwards, so that tlie sides near the top of the cup are parallel with corre-
sponding parts of the opposite side. Surface of plates, as shown from the
gutta percha impressions, beautifidly ornamented with elongate nodes or
riilges pa.ssing out from the centres of the plates to their sides, but not con-
tinued to adjoining plates.

Basal concavity narrow, and moderately deep. The radials rapiilly
tapering to their lower ends and rather small, not larger than the second
costals, which are considerably larger than the first. Fir.xt costals (piad-
rangular, once and a half as wide as long ; the second hexagonal, being
truncated at the upper end. First distichals about a third smaller than the
upper costals ; the second quite small and the palmars still smaller. First
interbrachial larger than the radials, almost as wide as hijjh, those of tiie
second row together smaller than the first ; the interdistichul sub-rhomboidal,
the upper and lower angles truncated,

Ilurhon and Lomlltij. — Niagara group; Racine, Wise, and Chicago, Ills.

Ilciiidrks. — The basal concavity in the casts is deeper than it appears
in the gutta percha impressions, and there are shallow grooves passing out
from it in a radial direction, which are not seen upon the impressions, and
give to the cavity in that state of preservation a decidedly pentapctalous
aspect. In specimens in which the plates are but partly dissolved, the sur-
faces generally show concentrating lines around the margins of the plates,
which probably represent mere lines of growth.

EuoalyptOCrinUS VentriCOSUS W. and Sr. (nov. spec).
Plate LXXXIII. FhjH. 11 and 12.

Syn. EHcalyptocriHHt cahtiu, RoEMEn, 1800 (not Hall 131.3) ; Silur. Fauiui West. Tcim ,
p. 48, Phte 4, Figs. 3 a-e.

A small species, in its general form subovato, slightly depressed at the
poles, its greatest width a little above the arm l)ases. Dorsal cup low
saucer-shaped, the sides evenly rounded, its height less than half the length
of the arm compartments ; the plates flat or nearly so, marked in well pre-
served specimens by irregidar, delicate linos running to the sides, but not
communicating with those of adjacent plates.

Basal concavity narrow and very deep, obscurely pentangular at the

■'

842

TIIK CULNOIDKA CAMKUATA OF NORTH AMERICA.

outer margin; the basals very Rmnll, occiipyinj.f only the bottom part.
Kadials vury long, only half their length exposed to view; tlje attenuate
longer half incurving and forming the sides of the concavity ; the exposed
part wider than high. Fir.-<t costals quadrangular, their width once and a
half their length; the second a little larger and hexangular, their upper
angle broadly truncated by the interdistichals. Distichals nearly of equal
size, and almost as large as the axillary costal; the upper angle of the
second so extremely obtuse as to almost forni a straight line ; the fixed
])almars moderately large and (juadrangular. First interbrachial large,
geneially as wide as long ; the upper part broadly truncated by the two
plates of the upper row, which together are as large as the first, and rise to
the second arm plate. Interdistichal rather narrow and long. Partition
walls narrow, not more than half the width of the arms, except their upper
ends which widen conspicuously toward the sunnnit. Summit .'(omewhat
flattened ; the central space closed by a short pyramid of small plates. The
arms rounded on the back, projecting slightly over the sides of the parti-
tions ; the three proximal plates single, and higher than the succeeding ones
which deeply interlock.

Horizon and hicuVdy. — Niagara group ; Decatur and Wayne Cos.,Teini.

Ti/pcs in the Museum of Comparative Zoology, and in the collection of
Waehsmuth and Springer.

litindrlin. — This species differs from E. udatus, to which Roomer
referred it provisionally, by the much more depressed form of the dorsal
cup, the proportionally greater length of the arms, the form and size of the
various plates, and the mode of ornamentation.

Euoalyptoorinus orassus Hall.
Plate LXXXI. Figs. 1, 3, 3, 4, 6, 6, U, 15.

1803. lI.M.i.; Triiiis. Albany lust., Vol. IV., p. 107; also 20lli Rep. N. Y. State Cab. Nat. Hist., p. U\
I'lalo II, Fiirs. 2, » (secniid cd., p. 30.5); also, 2Slb Hep. (second ed.), p. IH, I'lato 17,
Figs 1-11, Plate 18, Figs. 1-0, and Plate 19, Figs. 2-.5.
IS'.i. C) II.II.L and WiiiTFiEi.i); fi.'ol. Siirv. Ohio, Pabvont., Viil. IT., p. 120, Plate 0, Fiir. 11.
ISSl. Coi.lkt; lltb Ann. Hep. of Gool. and Xat. Hist, of Indiana, p. 272, Plate 17, Figs. 1-11, Plato
IS, Figs. 1-9, and Plate 19, Figs. 2-5.
Syii Fn'itliiptocnnm roiislriclu', II.m.l; ibid., p. 273, Plate 15, Fi,g. 1.
Svii. Eueali/ptocriiiiu chieagoemis, WiNcil. and Marcy ; 1805, Mem. Boston Soo. Nat. Hist., p. 90.

A large species ; the crown sometimes reaching a length of 10 cm. by
6 cm. in width ; its length, as a rule, twice the width ; the length of the

CALYFl'OCKINID.E.

343

dorsal cup to the top of the interbrachiiils and iiitoidistichals ahiiost ccjual
to tlie liuiglit of tlie compiirtments for tlio reception of the arms. Dorsal
cup subturbinate, inassivo, broadly truncate at tlic lower end, and the
bottom part deeply excavated, the sides straijjiit or a little concave ;
surface of the plates Hat and without ornamentation ; the suture lines
obscure.

Basals small, at the bottom of a deep, funnel-shaped concavity, and
forming with the inflected lower part of the radials, at the inner floor,
a rather large cone with a pentapetalous axial canal of moderate siy.e.
Radials very large, much longer than wide, forming a broad, slightly
spreading cup, which extends out laterally far beyond the sides of the
column. First costals quadrangular; their length and breadth (([iial; the
greatest width at the base ; the lower and lateral faces convex. Second
costals .smaller than the first, generally pentangular, occasionally the upper
angle slightly truncated by the interdistichal. First distichals almost as
largo as the axillary costals; the second but one third the size of the first.
First palmara very short and trigonal. First interbrachial almost as large
as tiie radials; length to width as ;") to 3; its greatest width at the inter-
costal suture line, whence it rapidly tapers to both ends; all sides concave.
The two plates of the second row either separated from the first, or lightly
touching its npper angle, and both together .about two thirds the size of the
first; they rise above the arm bases in form of n square projection. The
interdistichal is of a similar form as the two npper interbrachials, but one third
smaller. Ventral disk, deprived of its appendages, pyraniidid, the neck-like
upper part proportionally long, widening at the top, the compartments .sur-
rounding it deep. These are constructed of the keel-like partitions ascend-
ing from the back of the plates of the first row, and the wing-like extensions
of the upper row, which meet each other at the middle of the third row,
resting with their inner edges against the protruding surfixces of the plates
constituting the second and third rows. The form of the plates of the first
ring, as viewed from the inner cavity, is similar to that of the first inter-
brachials; they are as large, and also attenuate at l)oth ends. Tiie plates
of the second ring, which are quite mas.sive and elongate, form a leversed
funnel with its long tube pointing upwards; those of the third ring are
short and narrow, and those of the fourth rather long and wider aliove than
below. The canal within the neck widens toward the extremity, and the
top is closed by a short pyramid of small, irregular pieces snrrounding the

844

THE CKINOIDKA CAMKIUTA OF NORTH AMKRICA.

)

iiiiiiH, whifli is gonenilly closed in the Mpeciiiiens. The edges of tlie partition
\vall.i taper coiLsiderubly upward, being quite thin above, rather tliick below.
Arms llattened at the back, stout, a little tapering at the upper end. They
are conipo.sed of extremely short, tranverso pieces, which very wlightly
interlock ; the four proximal joints wingle and resting between the protrud-
ing upper parts of the intcrbrachials and interdistichals. In very nuiture
specimens, in which tlie.se projections are comparatively longer, tiiey some-
times enclose 5 to G joints. Column tapering downward, the joints much
the longest at the upper end ; the nodal joints long, and wider than the
intervening younger ones, their outer margins slightly convex; the joints
near the root very short and of uniform size. The root is composed of hun-
dreds of small branchlets, most of which arc run out horizontally.

IIui'!.""n dial Localit//. — Niagara group; Waldron and llartsville, Ind.,
Green Co., 0., and Chicago, Ills.

Tijpes in the American Museum of Natural History at New York.

RviiKirlcii. — This .species is extremely variable in form and proportions,
but, as iv rule, the cup in the older specimens is more elongate, and not
unfrequently constricted near the middle, thereby producing a sliglit con-
cavity at the sides. The ba.se in .some specimens is so broad as to give to
the cup a subcylindrical outline. In all specimens, however, the base extends
far out beyond the sides of the stem, and this, together with the unusual
length of the first costals, and the extreme . hortness of the arm joints,
distinguishes it readily from all other American species of this genus.

Euoalyptocrinus ovalis (Troost) Hall.
Plate LXXXII. Fitjs. 1, 2, 3, 4, S, 6.

1819. EueulyploeriiiHs ovii/ia — Troost; Ciitalogue of Criiioidca.

1874. Euc(i///ji/oi-riiitt.t oi;i/ii.i (in error lor E. ovn/ix) — IIai.i.; first rdil. 28tli Hep. N. Y. State Miis. Nnt.

Hist., I'liitc 17, I'igs. 12 ami 13 (the error rectificil in the secoud edit, of tlio same report in the

exphinnlii)ii of the plates).
1S83. Eiii-ii/yjifmriiiiis uvii/ia — W. and Sp. ; Rcvibion PaliEocr., Part ITT., p. 134.

A small species. General form ovoid, curving regularly from base to
summit. Height to width as four to three in mature specimens, and six to
five in very small ones. Greatest width a little above the top of the dorsal
cup. Height of the cup, compared with the height of the partition walls, as
two to three. Surface of plates smooth and without ornamentation ; the
suture lines indistinct.

•

CALYPTOCllIMD.E.

846

Bftsal concavity a little wiilcr tlinn the column, and rather deep, the bns<al
plates occupying almost its whole width. Ikdials curving abruptly inward
nt the lower end, forming n sharp edge at the bottom of the dorsal cup ; the
exposed npper part wider than long, and nearly as large as both costals to-
gether. First costals once and a half as wide as long ; the second a little
wider and pentangular. First disticlmls almost as large as the costals, the
second one third smaller, and the arm-bearing palmars about linlf the size of
the second distichals and pentangular. First intorbrnchial large, subcirculnr
in outline though actually decagonal ; it meets the two succeeding plates,
which are as long as the first, and near the lower end almost as wide ; the
upper parts tapering rapidly to a rather sharp point, which rises to the height
of the fourth arm pieces. Interdist'chal narrower and shorter than the two
upper interbracliials ; the lower end angular and barely touching the upper
angle of the adjoining costal ; the projecting upper end narrow and truncate.
Compartments for the reception of the arms deep ; the partition walls thin
throughout, their width at the lower end half that of the arms, the outer faces
flat. The summit closed by a small rosette of about eight pieces without
additional plates. Arms very gradually tapering, the outer face slightly
convex ; they are composed of moderately short pieces, which interlock
from the fourth plate. With the exception of the partitions nothing is
known of the construction of the disk. Column round, the no'lal joints
high and cylindrical, the younger joints a little narrower; axial canal
pentalobate.

Horizon and Localiti/. — Niagara group ; Waldron and Ilartsville, Ind.

Ti/pcs in the American Museum of Natural History at New York.

lictnarks. — This species has such close affinities with .E". c>t<.s'.s!<s that it
might be taken for its younger stage ; but on close inspection it will be ob-
served that the specimens have all the characteristics of an adult form. The
arms not only are biserial, but their plates are almost transversely arranged.
Moreover, the arms are placed deeply in between the projecting upper ends
of the interbracliials and interdistichals ; only in young specimens the tips
are almost on a level with the distal faces of the arm-bearing palmars. It
differs from E. crassus in its much smaller size, being only from 12 to 22
mm. in length by from 10 to 15 mm. in width, in the more evenly ovate
form of the crown, in not being truncated at the lower end, and in having
much shorter cost'',ls, and proportionally larger and pentangular arm-bearing
palmars.

'■\3ir»*r

840

rilK CKINOIDEA CAMKHATA OF NOHTII AMKUICA.

EuoaljrptoorinuB inoonspeotus RiNduenEKo.
J'/iitc LXXXIIL Fi.js. 1 and J.

ISSt. lliNQLEiiKiui ; I'rocml. Aeiul. Niit. Sci. I'liiU., p. MS, I'lutc 3, Fig. 5.

Of ratlior largo size. Dorsal cup deep, occupying almost one half of the
length of tiio crown ; semi-ovoid, the sides decidedly convex, rising gradu-
ally to the middle of the second costals, thonco almost vertically to the top,
so that the plates at the upper end are parallel to those of the o])posito side.
Plates flat — the general curvature excepted — and without ornamentation
or other markings,* the suture lines indistinct.

Basal concavity narrow and fdled completely by the upper part of the
column. Radials about as long as their width near the top, rapidly tapering
downward, the extreme lower end gently curving inward and taking part in
the columnar concavity; the sloping upper faces very short. First costala
as wide as long, a little narrower at the upper end, the sides slightly convex.
Second costals as long as the fust, widest at two thirds their height, some-
times the upper angle slightly touched by the interdistichals. First distichals
a tliird smaller than the upper costal, the second very small, and the .suc-
ceeding palmars still smaller and irregularly pentangular. First interbrachial
extremely large, decagonal, about a third longer than wide, attenuate at
both ends ; the two of the second row shorter, and together narrower than
the first, their upper and lower ends forming re-entering angles. The
interdistichal approaching the two upper interbrachials in form, but con-
siderably smaller; its upper end squarely truncated, and rising to the third
arm plate. Partition walls narrower than the arms, and of uniform width
throughout ; their outer edf.fos flat at the proximal, and convex at the distal
enil. Arms gradually tapering, rounded exteriorly ; the three lower joints
single, and a little longer than the upper, which arc extremely short. Struc-
ture of disk and summit unknown.

Horizon and Locidifi/. — In the white limestone at the upper part of the
Niagara group ; Rochester, N. Y.

Jicmarh. — Nearest to /:,'. cntxi^uft, but the sides of the dorsal cup dis-
tinctly rounded, the base not truncated, and the ba.sal concavity very much
smaller.

• HinpfiirbprR drspribnl the siirfiire ns " firirly riignsp ; rugir giviiij^ evidence of irrrguliir radintioiis
from llir lar^'or |il,ili's." \Vi! jiiivi' raicrutly cMiiiiiiMMl his lyiic, but cannot discover nny onmniciitution ; tlio
rouglnipss upon the surface is evidently caused by weathering.

CALYinOCHINID.K.

347

EuoalyptoorlnuB Lindahll W. & Sp. (nov, npoc.)
Plate LXXXII. Fifj. 9.

18M. Amoricnn Gcnliijfist, VdI. \. (Sriilcjiliri), [i. l.H).

Sjii. Eiiiuili/iiliK'i-iimi ll'ur/inii S. A. Mmi.kiii 1S91, Gcol. Hip. Ill,, null, 3, p. fiS, I'lali' t, Fijj- i.

Above inediiuii wizo. Most roiniukiiblo for its heavy, roumlod aims, which
to their full Icnjjth are oleviiteil proiiiinentiy iiliove the outer fiiceH of the
partitioii walls, so that the liitter form the bottom of a deep groove. Doiwil
cup seiiii-globoso, its lower concavity not larger than the width of the stem,
and enclosing only the ba.sal.s, which are hidden from view by a narrow,
round stem. IMutes not distinctly orimmented, merely showing u roughened
surface. Suture lines slightly grooved.

Riidiiils rather large, as long as wide, rapidly .sloping to the lower end ;
their lateral faces three times ns long ns the slanting \ipper ones ; tin-
superior face concave. First costals quadrangular, smaller than the rndi-
als, a little wider than long. Second costals hexangular, wider and longer
than the first; their .sloping upper faces longer than any of the otht-rs ; the
npper angle slightly truncated by the interdistichal. First distichals smaller
than the axillary costals, the .second less than half the size of the fir.>t, nnd
subquadrangulir. Palmars three in the calyx, l ransver.sely arranged, rounded
on the back. First interbrachial ten-sided, os large as the radials. longer
than wide, widest at the middle ; the two of the second row nearly three
times as long as wide, rising to the height of the third palmars. The inter-
distichal a little .shorter and narrower than the two upper interbrachials com-
bined. The walls forming the compartments taper gradually to near the
upper end, then widening rapidly, and curving abruptly inward so as to form
a Hat surface at the summit on a level with the tips of the arms. Arms
rather short, very heavy, almost cylindrical. They rise above the sides of
the partitions much more conspicuously than is known to be the case in
any other species, their tips being lifted out from between them almost
completely.

Horizon and Loralitij. — Niognra group ; Wayne Co., Tenn.

Ti/pp in the Illinois State collection.

The species is named in honor of Dr. Josua Lindahl, the eminent Zoolo-
gist and Director of the State Museum at Springfield.

TT^sm

^xapwtir.

348

TIIK CHINOIDKA CAMEKATA OF NOUTII AMKRICA.

Eucalyptooiinui magnus Woktiikv.

I'tutf l.XXX/l. Fl;/x. 7, S.

1S7S. Woutiikn 1 ami. Hip. Illiii<ii>, Vnl. VI , p. sol, Pluls ij, Fig. 3.
iHiiJ. \V. iimlM-. ; Ui'tiMcm I'lilivocr , Purl III., |>. l:i:i.

«vii. Kiii'iilitiilm-fiiiHii (iiiibi/i S. A. ^liLLku i Ailv. Hlit'cli 17tli Itrp, Gcul, Surv. Miuourii p. 30,
I'lulr 7, FiK". 5, 0,

A liirgo M|iet'ic'.>(. Doisiil cup doprtwetl tiirbiiiiUt', liui^lit ninl wiiltli uliont
lis Mcvi'ii to ton ; tlie lowor end obtiLsoly coiiiciil, riipiilly Hpiemliiij,' IVom tlio
top of till' iiuliiils to tlio top of llio lii'Mt iliwlicliiilM, tlu'ii abniptl_y tiirniiij(
iipwurili until nt thu uppc>r end tliu HiduH iiru piirullul witli tlio.xc of tlic oppo-
Hito side. Tlio upper interbnicliiiilH Hoinewliut dupreHst-d, ho as to give to llio
cup, a.i Hoen from above, an olwcuruly peutalobato outline. I'liile.s alinowt
Hat ; tbu Hurfiu'o sinootii or finely granulow ; Huture lines wli^litly j,'i'ooved.

Itasal concavity niurow, completely filled by tbu column. Kadial.s, an
exposed to view, wider tluin long, rapidly wjireading upward, tbeir upper
fiices twice as wide as the lower. Firnt costaln Homewbat Huudler and (|uad-
rangular; tbe sides sliglitly convex. Second costals beptangular, wider and
Idiijjer tbiin tbe first ; tbe sloping upper faces convex and unusually sleep ;
tbe upper angle broadly truncated by tbe interdisticbal. First dislicbnls as
large as tbu axillary costal ; tbe Mccond less tlian lialf tbe si/u of tbe fir.st;
tbu arm-bearing palmars trigonal and cjuitu small. First interbracbials tbo
largest plates of tbe cup; decagonal, but sub-rbomboidal in outline; tbe sides
more or less concave. Tbu two plates of tbe second row togetber wider tbiin
tbe first, witb re-entering angles at tbe upper and lower ends. Interdis-
ticbiils large, elongate, rising to tbe bcigbt of tbe fiftb arm plate, tbe sidea
fiicing tbe costals concave, tbe upper and lower faces broadly truncated. Of
tbe arms only a few of tbe lower plates were preserved, wbich are extremely
sbort. Tbe partition walls are broken away in tbe specimens, but were, to
judge from tbe places for tbeir attacbment, imusuolly beavy.

Horizon and Localih/. — Niagara group; Wbitu's creek, near Nasbvillu,
Tenn., and Decatur and Wayne Cos., Tenn.

T^pe in tbe collection of Prof. S. S. Gorby.

lieniarks. — Tbis si)ecies is most remarkable for its large size, and is
readily distinguisbcd from all otber known spucies by its peculiar form.

'f/

C'Ar.YPTOCRINID^Ii:.

840

EuoalyptOTinui deproiaus ^^ A. Mh.i.kk.

riuu Lxxxiii. Fiijs. .J, 4„, 4b.

wo 8. A. Mii.i.iiii Jiiiim. Ciiiciii. Hiip. Nut. Ilinl., Vol. III., p. fM, I'liili 7, V\\(i. I, In, i.
my \f. ami Hr.i lluvitiuii ruliiiicr., i'art III., |i. l»a.

Of inodunito hIzc. Crown Hiihc^liiuliiial, twico iih liigli m \\'u\o, a littlo
tnporing to the iippor ciid, iliMtiiictly tliitteiiLMl mid concnvo at tlio puloH,
Dui'Miil cup alnic-^t twice as wide uh high, the upper p'irt of the rudials and
thu cxircino ciid.s of tho lirst inloihrachials roriniiig the tniiicatcd liottoin,
the iippct part of the hitter and the fir^t costal^ gently curving npwurd, the
plates ahove parallel to thoHe of the opposite Hide. Plateii a little convex,
their Hiirfnce ap[)areiitly riigo.se. Lower concavity deeply and hroadly fnn-
nel-shaped, the hasal-s constituting hut little more than the bottom part.

Kadials slightly longer than wide; their upper half more or le.xs ho;i-
zontal in position, and not visible from a side view ; thu luv.er half lorming
the slanting sides of the concavity; their sloping upper faces rather long.
First cottals twice as wide ns long, a little .shorter than the second at the
median line; the u|)pcr end of the latter hlightly truncated by the inter-
distichal. First distichals about a third snudler than the upper costals ; tho
second half the size of the Hrst, their upper angles (juite obtu.se; the first
palmars very small and peiitiingular. First interl)rachial subrotundate, as
long as wide, those of the second row m long, but together narrower than
the fust, their upper ends rising to the base of the second arm |)lates. 'i'ho
interdistichal ha.s almost the form of the two upper intcrbrachial.s, but is
somewhat smaller. Partition walls nearly twice as long as the dor.sal cup,
moderately thin, the outer edges rounded to near the top, then slightly widen-
ing and curving abruptly inward and somewhat downward, so as to form a
shallow depression around the summit. Their upper ends enclose five rather
largo plates with a pentangular open space, the overlying plates being not
preserved in the specimen. The height of the calyx, as ob.served in the casts,
is about equal to the greatest width acro.ss the fir.st distichals, and that of
the dorsal cup ecpial to that of the tegmen but narrower; the tubular pro-
longation above almost as long as the rest of the calyx, nidening at both
ends. Of the arms only the proximal plates are preserved, which are com.
paratively long.

Horizon and Locality. — Niagara group; Cicero and Bridgeport, near
Chicago, Ills.

-fsm

■'ssm-mm^

350

THE CKINOIDKA CAMERATA OF NORTH AMERICA.

f
III ^|i

T//pes in the collection of \V. C. Egnn, Esq., of Chicngo.

Ilanurks. — Tiiis Hpceies diflcrs from nil preceding ones in the depressed
form of the dorsal cup, the width and depth of the hasiil concavity, and the
po.-iition of the radials which are almost at right angles to the plates of the
np; or end. It was originally described from natural casts, but Mr. Egan
has dnco obtained from the same locality a specimen with the plates intact,
from which our description is made.

Duitbtfal species described from natural casta,*

EuoalyptOOrinUS Sple^didUS (Troost) Ham. ami AVuitfikld.

1818. Troost ; List Criii. Tciiii., Proceed. Aiiicr. Assoc. Adv. Sci., p. 60 (willioiit desciiplion).
1873. Hall and Wuitfikld ; Geul. Surv, of Ohio, I'lda-out., Vol. II., p. XL'S, Plate 0, Fig. 12.

Closely allied to the preceding s[)ecies, and perhaps identical with it.
As in that species, the general form is subcylindrical, linttened at both ends,
the arms are twice as long as the dorsal cup, and the radials are not seen in
a side view,^or only their extreme ujjper ends; the disk, however, to judge
from the cast, is proportionally sliorter, and the first costals are higher. The
basal concavity cannot be seen in the specimen, but must have included the
preater part, if not the whole, of the radials. First castals quadrangular,
nearly as long as wide ; the apex of the second slightly truncated by the
interdistichai ; the distichals considertbly smaller than tiie costals ; the first
interbrachiiil large, a little longer than wide The proportions of the other
plates indeterminable. Disk hemispherical, the tubular canal in the cast as
long as the rest of the calyx, and funnel-shaped at the upper end.

Horizon awl LocnHtij. — Niagirra group ; Springfield, 0.

Tifpe in the collection of Professor Orton.

Euoalyptoorinus rotundus s. A. :MiLi.En.

18S2. S. A. MiLLKii ; Jourii. Ciiiciii. Soc. Nat. lli-t., Vol. V., p. 82, Plate 3, Figs. 4 and 4 n, /;, c

Of small size. Crown globose. The inner cavity of the calyx, as seen
in the cast, much wider than high, the canal within the neck wide and of
nearly uniform width. Dorsal ciip low-saucer shaped ; the basal concavity
small, and apparently filled completely by the upper joints of the column.
Radials wider than long, the upper face concave. First costals twice as wide

* We arc willinn to admit that most of these forms differ s|icci(leally from one another, l)ut we arc
unable to see liow the casts can hi' satisfactorily compared with species described from the test, especially in
a genns like Eiiail^vplorrimis in which the dilTerentiations arc but very slight.

CALYPTOCRINID^E.

351

ns long. Second costals about the size of ,iie first, a little higher at the
median line, their upper end slightly truncated by the interdistichal. First
distichals almost as large as the costals. The form of the other plates
indeterminable.

Horizon and Lomlihj. — Niagara group ; near Chicago, Ills.

'rijpes in tiie collection of W. C. lOgan, Esq., oi" Chicago.

lianarJcs. — Thi.s may be a small specimen of E. Elrodi, with which it
agrees in the general form, and in the proportionate size of the plates.

Euoalyptoorinus turbinatus s. A. Milleb.
Plate LXXXIL, FUj. 13.

18S2. S. A. M11.1.EH ; Joum. Ciiicin. Soc. Kiit. Hist., Vol. V., p. S2, Plato 3, Figs. 5 ami 5 a.

A rather large .species. In the cast, the calyx is nearly as high as wide,
the dorsal cup obconical, slightly constricted above the radials, the extreme
upper end abruptly curving upwards ; the suture lines are defined by angu-
larities, and the inner spaces of the plates are slightly concave. Tlie disk
appears depressed hemispherical, with ten well-marked longitudinal ridges
representing the ambulacral grooves.

Bisal concavity moderately deep and obscurely pentangular. Eadials.
as exposed in a side view, comparatively snuill, wider than long. First
costali quadrangular, m-arly as long as wide. Second costals pentangular,
a little larger than the first, the sloping upper sides steep, the upper angle
truncrted by the interdistichal. First distichals as large as the second
costal ; the second much smaller ; the palmars minute. First inteibrachial
a tliinl longer than wide, barely touching the radials. The two plates above
forming a rhomb with tlie two acute angles truncated. Interdistichal com-
paratively short. Length of the partition walls, and the neck-like prolonga-
tion of the calyx not known.

Iluraon and Locidil;/. — Same as last.

l)jl>e in tiie collection of Mr. W. C. Egan.

livmarhs. — This is probably a good species. Fragmentary .«!pccimens
with the plates intact, apparentl}'^ representing this form, occur in the
Niagi.ni group of Decatur Co., Tenn. The basal concavity is narrow, and
the radials have a truncation at the bottom, of which the edges project
rather broadly over the sides of the column. The truncated upper faces
of the ii:terbrachials and interdistichals supporting the partition walls are

352

TIIK CRIXOIDKA CAMERATA OF NORTH AMERICA.

extremely wide, the facets for the reception of the arniH are surrounded by
a raised angular edge, and the plates are covered with obscure radiating
ridges or rows of small tubercles.

Euoalyptocrinus Egani s. A. ^riLi.i;n.

Phtte LXXXIL Fiijs. 11 ami 12.

18S0. S. A. MiLLKii; .liiurii. C'iiiciii. Soc. Niit. llisl., Vul, III., p, 140, rinle 4, Figs. 1 a-c.

A very elongate species. Height and width of calyx as 8 to 5 ; height
of dorsal cup, compared with the length of the arms, as 2 to 5; the length
of the neck-liko prolongation to the tips of the partitions as 8 to 9 — all
measurements made from the casts. Dorsal cup a little higher than wide,
obconical, the bottom distinctly truncated and not excavated in the cast,
the sides very "^lightly convex and projecting conspicuou.><ly oA'or the sides
of the disk. Radials nearly as long as wide. The first costals longer than
wide, and narrower above thiin below ; the second of the same length, and
truncated l)y the interdistiehals. Distichals a third smaller than the costals.
First interbrachials almost twice as long as wide, widest at midway. Form
of the remaining plates indeterminable. Ventral disk but sliglitly tapering,
its upper margin curving abruptly to the liase of tlie neck, which expands
rapidly upwards. It ri.'<es apparently far beyond the arms, and tapers in size
as rapidly as it increases below.

Horizon and Locality. — Same as last, and the type specimens in the same
collection.

Euoalyptocrinus probosoidalis 8. A. Milleu.

Plate LXXXII. Fly. U.

1882. S. A. Miller-, Journ. Ciiicin. Soc. Xnl. Hist., Vol. V., Tlntr 9, Fig. 2.

Closely allied to the preceding species, but the calyx, to judge from the
cast, still more elongate, being to the b .«e of the neck over twice as long as
wide; the sides of the dorsal cup more convex; the tegmen higher propor-
tionally, less depressed at the toj), and nu)re evenly rounded. The neck is
more constricted in the middle, and more expanding at the summit, the tube
succeeding it thicker at the base, and apparently longer, reaching in the
type a length of 4.3 mm. by 12 mm. in width at the base, and 2 nrn. at the
upper end, tapering giadually. The plates of the dorsal cup, so far as
observed, are long, especially the first interbrachials, which are more than

CAF-YITOCRINIDTE.

353

twice ns long as wide, occupying fully one half the length of the dorsal cup.
The tube in its free state was covered by large hexagonal plates, very
regularly arranged.

Horizon and LomJit//. — Niagara group; Pontiac, O.

Remarks. — Miller descril)ed this species from a plaster cast in the pos-
session of Mr. A. McCord of Oxford, Butler Co., 0.

Euoalyptoorinus oboonious Hall.
Plate LXXXIIL, Fly. 13.

ISfi?. HALt.; aoili Rep. N. Y. StnUi Miisimm Nnt. Hist., p. 32.1, Plate 11, Tig. 1.
IS?.). W. mid Sr. ; llcvlsiuii rak-oor., I'lirt III., p. Ilia.

Diflering from all other American species of this genus in the arrnnge-
nieut of the basols, wliich form an ol)conical cup instead of being placed
within a concavity. Dorsal cup very long, sometimes almost twice as high
as wide, sharply pointed at tiie lower end. the sides straight to near the top,
wliere they slightly contract. Radials once and a half as long as wide, but
very little tapering, the sloping upper faces (|uite small. First costals
(|uadrangular, as long as wide, tlie upper face narrower than the lower; the
second costals of almut the same size as the first, but pentangular. Fir.st
distichals comparatively largo, those of the same ra}' in contact laterally;
the second very small. First interbrachials nearly twice as long as wide,
widest at nii<lway ; the two of the second row shorter. IrUerdistichals
unusually small, resting upon llie .-^loijing upper faces of the first distichals.
All other parts unknown.

lIurizoH and Localilij. — Niagara group ; Kacine, Wise, and Chicago, Ills.

CALLICRINUS i.'OimKiNv.

IS'iU. D'OuiilONY (r.////o(Y/«ffs); rnidmnip, Vol. 1., p. 45.

1878. A.N(iKi,ls; leonngr Clin. Slice, p. 1 1.

1S;9. ZiTiKi.; Ilamll). il. I'alrediit., Vol. I., p. 378.

18M. W. and Si'. ; Hc\i»ion I'idirocr., rait III., p. l.l.') (Proceed. .\i'ad. Niil. Sci. riiiln., p .IS?).

1891). HlxotKiiKlUi ; .\iiimls \ Y. .Vend. Sci , Veil. V., p. ;i()2.

Syn. Kiiiii-iiitirriiiiln Hisixom (mil .1. S. .Miller), ls.")7. Lclliiea Suep., p. 8(1.

Syn. EH,-iihji,lnrrhiii> (in part) lUl.l.; X. Y. State Mus. Xat. Hist., p. 322 (20ili Hep ).

In its general a,spect, in the form of .he calyx and arrangement of the
plates, closeh' resembling Encnh/ptncrlnus. The calyx also lias the form of
a wine bottle with long slender neck, and a deep concavity at the bottom ;
but the partition walls, instead of forming clewed compartments to the full

864

THK t'KIXOlDKA CAMKR.VTA OF NOKTII AMKUICA.

■ i ,

Icnyth of tlie nriiis, rise only to a certain liciglit, and are not closed from
above. The plates, as a rule, are liij,'lily ornamented, strongly nodose, or
cxtiiuled into long spines. The dor.sal cup is constructed of tlie same num-
ber of plates, and arranged in exactly the same manner a.s in EHvuhiptovrinm;
generally, however, tlie basal concavity is wider, and
only partly filled by the coliunn. In the construction
of the ventral disk also, the two genera have close
affinities ; the plates in both forms consist of foin*
rings, and in both of them the first ring is composed
of twenty plates, the second and third of four ; but
the fourth ring contains but four plates instead of ten.
and these have no wing-like extensions at their outer
faces ; the upper parts of their arms are free, and rest
directly against the walls of the anal tube. The parti-
tion walls, of which there are twenty in this genus,
are restricted to the plates of the first ring, and rise
but little above their general height, never touching
the plates of the second ring. Five of the partitions
are su|)portc'd by the interbrachials, five by the inteV-
distichals; the remaining ten are interposed between

Fui. 17. C<iltirrinuf. Siilo view
of nilyx, ^liiiwiut; the niili-
nu'iilarv hiirliliuni..

K ~ railials ; / — conlalx \ II =
(listiclinU; lAr - in(erl»rni>lil-
tl>i ill inliT'livtii'lml*; irV
= intcrriuiidl )inr(itiiili!t : /'//*
— inliTdimivlKil iiarliilMiiH;

!>/' intirpiiiniar i.ariiii..iii.; tlic tcH otlicTs, and Tcst upon tlic cdgcs of two palmars.

/ = llit' llrsi or IipwiT rinir of riii i *x ^'i' c i i • im i

,,i«t,., i„ ,1,.. ..KM. .on,, ll'es'e latter partitions are formed by wmg-like exten-

poH.Ml of IcH larifc ami len
piniill sutitri^iinnl |iii'ce!«; 2 ~
tlie |ilul4'H itf the i*eci)ii<l rhi^,
.1 = thone of the third ritif;,
^ — the platen of the fourth
ring.

sions from the ten .smaller plates of the first ring;
they rise to the .same height as the others, and separate
the two arms which in Kiirdh/jitniriiiiis occupy the
gamo compartment. The plates of the second and
third rings either are flat, the general curvature excepted, or they show
some inclination to forming faces of attachment for partition walls. The
four plates of the upper ring constitute the upper end of the anal tube,
which generally has a quadrangular opening. Arms robiust throughout,
closely folded, and composed, from the second or third plate up, of two
rows of transverse pieces. The partitions by which they are separated
rarely extend up higher than to one third the length of the arms. Column
round ; the axial c inal of medium size and pentangular.

Dis/ributio)). — The greatest number of species occurs in tlie Upper Silu-
rian of Gotland, and there arc one or two at Dudley, England, llie genus
is represented in America by four species in the Nir.garii group.
Callicriiius costatus (Hisinger) is the type of the genus.

CALYl-rOCKlNin^K.

355

Itemarks. — CaUicrmun is probably the forerunner of Eiirn/i/j)fi)pf!niis ; it
is built on the suniu plan, but its family cliaractcs wuru not, as yet, .so biglily
difl'erentiuted as in that genus.

Calliorinus Beaohleri w. and Si-.
Plate LXXXni. Fiffs. l^u, b.

1892. W. aud Sp. ; Aiiicr. Geologist, Vol. X. Sept., p. 140.

The calyx Im.s the usual for.n of the genus. Its height tn the base of the
tube one fourth greater than the width at the top of the dor.sal cup; the
height of the cup 11 nun., that of the ventral di.xk Ki unii., and the leuf^lli of
the partition walls Sunn. I)or.sal cup broatlly truncated at the ba.^e; the
sides almost straight, gradually expanding upwards. The radials aud costals
at the surface .sharply keel-shaped, especially the former, and the angularity
continued upon the distichal.s, but without attaining the prominence that it
lias at the lower plates ; the first interbrachials slightly convex, with a small
tubercle in the centre.

Ba.sab: .small and nearly of the .same size, forming a concavity which is
rather small and shallow for the genus. Radials near the upper end lully as
wide as long, and twice na wide as ai the lower part, which curves gently
inward to meet the basals. First costals twice as wide as long ; the second,
which are longer and wider, rarely truncated by the interdistiehal. First
disticlials twice as large as the .second, and but little smaller than tlit; upper
costals. The palmars .small and pentangular. First interbrachials longer
than wide, a little smaller than the radials ; the two above together nearly
twice as wide as the first, their upper ends rising to the height of the
second or third arm plates. luterdistichals but little smaller than the upper
interbrachials, and projecting upward in a similar manner. Ventral di.sk
conical, its sides convex. Tiie ten plates which rest upon the interbrachials
and interdistichals. respectively, and form the compartments for the recep-
tion of a pair of arm.s. are twice as high as the ten intervening ones, which
rest against the sloping upper faces of the palmar.s. There are in all twenty
])artitions around the disk, and each arm occupies a separate compartment.
The partition walls are moderately thick, and slightly grooved along their
outer faces. The ten larger ones ri.se to a level with the upper end of the
first ring of plates in the disk, of which they form wing-like extensions ;
they are sabre-shaped and pointed at the ends. The second ring of the disk

1 I

356

THE CRINOIDKA CAMERATA OF NORTH AMERICA.

conniHts uf fuur plates, which arc much nnrruwcr at the top tliiin nt the
bottom, and two of them are narrower tlian the others. ConHtriiction ol' the
anal tube, itn length, and the structure of tlu' arms unknown.

Horizon and Loealiti/. — Niagara group ; St. Paul, Ind.

Ti/pc in the collection of Wachsnuith and Springer.

Rinutrks. — The unique »<pecimen from which the above description is
made, was discovered by Mr. Charles S. Beachler, a very enthusiastic collec-
tor, in whose honor the species is named. He has since found u second
specimen at the same locality.

Calliorinus aoanthinus Hi.nuikueuu.

Piatr LXXXIII. Fig. IS.

1890. UiNorKiiKRG ; Aniinls N. York Acad. Sci., Vol. V., p. 302, Plate 3, Figs. 1 anti lo.

The speoiinons from which this species was described are quite fragment-
ary, only showing portions of the dorsal cup, and notliing of its super-
striicture, but enough is seen to indicate that the species i^ unlike any other
hL-retofore described. The dorsal cup evidently was very short, shorter even
than represented in Ringueberg's restored figure in the Annals, Tlate 3,
P'ig. 1, the lower ends broadly tr\incated. and almost as wide at the bottom
.i-< at tlio top. The cup rests upon the niedi.in part of t!ie large radials; the
lower end of the plates curves inward to meet the four basals, and the upper
end abruptly upwanls.

The biisals, together with the lower part of the radials, form a deep
ponnipetalous coneavity, which at the inner side of the calyx is represented
by a short cone, rounded at the upper end. First costals twice as wide
as long, tiic suture lines convex ; the second a little longer, their sloping
upper faces at right angles. The first distichals in contact laterally, some-
what smaller than the upper costals, wider than long, the upper face con-
cave ; the secoi) . much smaller, and the arm-bearing palmars smaller still.
First interhrsjhials almost as large as the radials, a little longer than wide,
subrotundrite in outline; the two plates above elongate, and togoiher much
smaller 'Jian the first. The interdistichal very small, resting within a notch
fornv.d by the first distichals. The faces suj)porting the partition walls
projecting considerably over those supporting the arms. The axillary costals
and first interbrachials u o ex;<?!i;led into long, rather sharp .spines, proceed-
ing from the middle of the plates and oK-ccted obliquely upward. In addi-

^^m-

CALYITOCRINID^E.

35(

ion to the npinoH, the plntes have strong ridges or angular protnberanceB
pa.s8ing out to the sideM, wliere tliey meet witii 8iniilar ridges f'roui the
phitfs below. The rudials have six such ridges, one proceeding to the (irs»
costais, one to the busals, two conimunicato with those of thi- interbnichials,
and the two remaining ones, which form a well defined pentagon at tlie
lower margin of the cup, pass out to the adjacent radials. The smaller
plates in the upper part of thi dorsal cup are convex, and slightly angular
in the middle.

Horizon and Localltij. — I^ower limestone of the Niagara group. Lock-
port, N. Y.

Tjijye in the collection of Dr. E. N. S. Ringuebcrg.

licmarkn. — Dift'ering from all other American species in the depressed
form of the dorsal cu|), the surface markings of the plates, and in the num-
ber, form, and direction of their spines.

Calliorinus oornutus Ham..
Plate LXXXIII. Fir/s. 15, 16, 17.

lSfi7. Kueali/pheriiiHf rnr,iii/n.i— IIai.i.; 20iIi Kcp. N. Y, Sliitn Cal). Xnl Hist , p. 'M2. Plntr 11, Y'lgt.

S', !•, 10.
1S82. Eiieiili/plocriimt curiiiiluf — II. I'. WiiiniKLi) ; (icul ltc|i. Wi^^., Vol. IV., p. 2S5, Plate 10, Fig.s.

5-S.
18S5. (?) /iwaljfptorriHH) eorHntiu — W. aiiil S. ; Rcvisiim rnlirnoi-., I'lirt 111 , p. 1S3.

Syii. Eiiculiiplnrrinas roriiu/in, var. exi-araliif IUli, ; 20lli Ufp. N. V. estate Cab. Nnt. Hist., p. 322,

riatc 11, Figs. 0, 7.

Calyx, as seen from intern.-il casts, more than twice as wide as high, dor-ai
cup broadly truncated, and enorinou.sly excavated at the bottom, the sides but
very slightly expanding upwards, being almost vertical. The t-xcavation at
tlie bottom extends to nearly the full width of the cup, and to two thirds its
height; the circumference is sharply pentangular with straight or sliglitly
re-entering sides, the inner face grooved toward the angles, which are
directed radially. The arrangement of the plates is rarely seen upon the
internal cast-!, and not much better in the gutta pcrcha impressions from
the exterior. In the latter, however, it appears that the middle of each
radial bears a long spine, which pa.><si's outward and slightly upward, .tml
occupies the lower margin of the cup. From each side of the.se spines,
strong ridges proceed to the np])er lateral margins of the plnte.s, which meet
with similar ridges from the interbraehials. A .'<omewhat larger ridge runs
to the costais, where it divides and sends a branch to the distichals. From

ii#>e..*ifc-' •''■»,:;

a58

TIIK CRINOIDKA CAMKRATA OK NOKTH AMKRICA.

tlio lower Hide of the Hpine tliere !« but one ridge, wliich leads to the biiHalH.
The ridges upon the first inti-rbrachiiils cuhuiiuite in a sharp node in the
centre.

Basals compuratively small, occupying but half tiie deplli of tlie con-
cavity. Kadials very large, the lower half curving abruptly inward, and
loriuing a sharp edge upon which the cup rests. Costals very t<uiall, tiic
two together less than half the ."ize of the radials ; the first from two to
three times as wide as long ; the second a very little higher and truncated ut
the top. Distichals, palmars, and interdistichals very small ; the first in tcr-
brachial unusually large, and as wide as long. Ventral disk stout, and to
the base of the tube twice as high a.s the dorsal cup ; the sides rising verti-
cally to the top of the trigonal plate of the first ring, whence they slope
slightly to the summit of the ten larger ones, and more rapidly to the tube,
which near its base is moderately thick. The ten larger plates of the first
ring are longer than the whole dorsal cup, the intervening trigonal ones but
half as long. The former, as seen from gutta percha impressions, have long
spiniform appendages, which probably reseml)led those of Cdlllrriiiiis miiixhi-
.sw((Vw(^» Angelin ( Icono<fr. Plate 28, Fig. 14); the}' are a little compressed
at the sides, and are directed upwards and outwards. The trigonal pieces
also rise into spiniform partitions, but these are shorter and smaller gener-
ally. Structure of the arms unknown.

Ilorizon and Ijiwdliti/. — Niagara group ; Racine, Wise, and Chicago, Ills.

Tf/pes in the N. Y. State Cabinet of Natural History rt Albany.

licntiirks. — The large collections of Mr. Thomas A. (Jreene of iMilwaukeo,
and Mr. W. {'. Kgan of Cliicago, contain a few specimens in which the dor-
sal cup is unusually expanded at the arm bases, less broadly truncated at
the bottom, and the first costals somewhat larger; while otherwise agreeing
with the rest of the specimens. These specimens do not agree with C. vor-
nutiin, var. ('3-t'nr((tits Hall, which was not accepted by Whitfield, and we think
that both these forms may be regarded as variations of C conuttus.

(?) Calliorinus ramifer v. Kohmku.

1S60. EuetilDploeriimt ramifrr — Rokukh Siliir. Fiiuiiii West. Teiin., p. 51, Plato 4, Figs. 4fl, 4, e,
I">S.J. Eudili/iilorriHHt rimifir — W. and Sp. : Ui'visiim I'alivncr., Part 111., p. IIU.

This species is only known from the general form of its dorsal cup, and
tliere is some doubt wiietliei' it should be referred to CuUirfinus or to a new
genus. It differs from the other species of that genus in the size of its bas-

CALYPTOCBIXIDi^t:.

369

nl«, which aro Iiiryely rcpreHented at the oiitor walls of tho dorsiil cup ; inoro-
ovor tlio uricMitiitiuii of tlio puntiingiihir basal concavity i8 revurwud, its angles
being directi'd intermdially, wliilu tiioy are radial in C. cornutun and other
spocioH. Dorsal cup nearly as high as wide, the base broadly truncated, its
lower margin a little projecting laterally and Ibrniing a sharp edge ; the
sides gently curving to near the top, where they slightly contract. The
suture lines are not shown in lloeiner's type, but we can see from a fragmen-
tary specimen in our own collection that the basals are very irregular ; three
of them are quadrangular, tho fourth pentangular and larger, the latter
broadly truncated and supporting a radial, which is smaller than the others
and slightly convex at the lower face. The other three basals, which rest
each one between two radials, are distinctly angular below. First costals
(|uadrangular, once and a half as wide as long ; tho second considerably
larger and pontangidar, the disticlmls arching over its ujjper angle. First
interbrachial largo, decagonal, almost as wide as long. The platos thin, and.
so far as observed, wiihout surface markings, except ob.scure angularities fol-
lowing the median lines of the radial.<3 and brachials, and a small conical
elevation within the middle of the first interbrachial.

Horizon and Lom/I'i). — Niagara group ; Wayne and Decatur Cos., Tenn.

Ti/pe in the Mineralogical Museum, at Breslau, Germany.

liemarks. — If this is a true Cdllicriiitis, it differs from all the other species
of this country, as well as of Europe, in the large size of its basals, which in
no other species are exposed along the sides of the cup.

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