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PALEONTOLOGY:

Volume VIII.

AN INTRODUCTION TO THE STUDY

GEN ERA

Pal^^ozoic Brachiopoda

PART I.

BV

JAMES HALL,

STATE GEOLOGIST AND PALEONTOLOGIST. ^

^'5

ASSISTED BY L | \^f^l ^ ^

JOHN M. CLARKE. J^'\ 1 1

3

ALBANY, N. Y.:

CHAKLES VAN BENTHUYSEN & SONS.

1892.

Q'-

1 !_

Oo

I
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N

on

State op New York, )

Albany, June, 1892. )

Publisheii under Iho su]>ervision of the Trustees of the State Museum of Natural History, pui-suant to
chapter 355 of the Laws of 1883.

DEDICATION

7o His Excellenaj

RO SWELL P. FLOWER,

Governor of the State of New York:
Sir:

I have the honor to present to your Excellency a new volume of the Natural
History of the State of New York, forming a continuation of the work on
the Palaeontology of the State.

This volume together with one other, already far advanced in its prepara-
tion, will complete the work upon the revision of the genera of the
Paleozoic Brachiopoda. The investigation, begun many years ago, and for a
long time suspended, was resumed only in 1888, and while in the outset laboring
under many disadvantages for want of adequate collections, the difficulties have
been mainly overcome and the author is able to present the volume in a satis-
factory form. The advance in our knowledge of this class of fossils during
the past twenty-five years, and the later accumulation of material from various
sources, for the illustration of the work, are the causes whicli have expanded
the proposed Part ii of Volume IV of 1867 into two volumes, of which this is
the first. The work has for its final object the bringing together, under one
title, a summary and revision of all the genera of this class of fossils known
in the rocks of New York and the adjacent States, to the Coal Measures
inclusive. This will also serve as a revision of the genera and species already
described in Volumes I to IV of the Palaeontology of New York, published
during the interval from 1847 to 1867.

The publication of the volume has been greatly delayed by causes beyond
the control of the author, but the Act of the Legislature, Chapter 170 of the

iy DEDICATION.

Laws of 1892, has made provision for the completion of this aiid the subse-
quent voUnne. The present volume is the first fruit of that act, and I trust
that its publication may give you personal satisfaction, and that it may com-
mend itself to the student of geological science and prove worthy of a place
among the great series of works comprising the Natural History of the State

of New York.

I have tlie honor to remain,

With great respect,

Your obedient Servant,

JAMES HALL,

State Geologist.

Albany, N. Y., May 18/A, 1892.

TABLE OF CONTENTS.

Paoe.

DEDICATION ------ iii,iv

TABLE OF CONTENTS ----------- v-vii

PREFACE ------------- i>;-xvi

1. BRACmOPODA INARTICULATA - - - 1

LiNUULA --------------

IS

LiNGULOPS ------------

LlNGOLASMA ----------- '-"-"^

Lakhmina ------------ -o

Trimerella .-----------'a

DiXOBOLUS ------------ -^1

MONOMORELLA ------------40

r> ----- 44

Observations on the Develoi)mei)t of tlie Platform, etc. ----- 46

LiNGULELLA ------------

KQ

LiNOULEPIS ------------

Barroisei.la -

TOMASINA ------------- 65

Oboi.ella ------------ DO

Leptobolus -----------

Elkania --------- -- '->

78
Paterula -

Obolus ------------- 80

aulonotreta -----------

00
ScHMIDTIA ------------

00
MONOBCLINA --------

84
Neobolus ----------

Spondylobolus -------

8fi

MiCKWITZIA ------------

87
QO

DiSCINOLEPIS ----------

.- ------- 90

IVUTDRGINA ------

------ 94

ScHIZOPHOLIS - - - - -

05
Volborthia -----■■'"

07

IpHIDEA ----''■""■_'__. pg
ACROTHELE ------------

101

ACROTRETA

vi TABLi: OF CONTENTS.

Pahk.
(\lNOTRETA - - - - - - - - - - - - -104

DisriNOPSis ------ - 105

iSl.NXAKSSON'IA -_.--------- 107

Mksotketa ------------ 1(19

SiPHONOTRETA - ----.------] 1()

ScHIZAMBO.N ------------ 113

Kkvskklingia - - - - - - - - -. - - -117

Helmersenia ------------ 119

DisfiNA, Orbicui-a, Orbkiloiiiea, ScmzivrKKTA, DiscixiscA, Lindstroemella,
QShlerteli.a, Rokmerei.i.a --------- 120

Trematis ------------ 128

SclllZ(X-RAXIA ------------ 142

Crania ------------- 14(5

Cranieixa ------------- 153

CARDlNOfRANIA ----------- ]54

Pholidops - - - - - - - - - - - - -155

Note to litige 128 -------- jgo

CONCLUSION - - - . 161

SUPPLEMENT TO THE BRACIIIOPODA INARTICULATA - - - - 171

II. HHACIIiOPODA ARTICULATA --------- 185

Okthis - 186

Orthis ------------- 192

Plcctortliis ------ 194

Diiiorthis ------------- 195

Plffisioniys ------------ 19^

Ilebertella ------------ 19^

Ortliosti-oiihiii ----------- ]gg

Platysti'opliia ------------ 2OO

Ilot.erorthis ------------ 202

Bil()l)ites ------------- 204

Ualinaiiplla ------------ 205

Rhipifloiiiella ----- 208

Scliizoplioiia ------------ oil

Ortliotichia - - - - - - - . - - - -218

Eiiteletes -- 214

List of (tenera and Speciep ---------- 900

Supplementary Note on the (tends ORTHif! - 227

BiLLING.SELLA - - - - - - - - - _ . -93()

Protorthis - - - -.- - - - - _ . _ .)._j|

Clitambonites ------- 233

Polyt(ec:uia ----- 239

ScENiniDM -------- 241

Orthidium 244

TABLE OF CONTENTS. vii

Page.

Strophomena ---------_-. 245

Orthothetes ---------... 253

HlPPARIONYX --- -... 257

Kayserella ----------.. 259

Derbta - - 2(51

Meekella ------------. 2(54

Streptorhynchus --------.._ 2(57

Triplecia ---...- 269

MlMITLTJS -----•------.. 272

Streptis ------.--.... 274

Lept^na ------------- 27(5

Raj-inesquina -----.. 281

Stropheodonta ----.---... 284

Strophdxella ------.--... 290

Leptella --.--------. 298

Lept^nulopsis ---------... 294

Plectambonites ---------.. 295

Christiaxia ------------- 298

Lept^nisoa -----.----.. 299

Davidsonia ------ - 301

Chonetes ------------ 303

Chonetina -------- 310

Chonostrophia - - - - - - - - - - - 310

ChONi 'PECTUS ------------ 312

Chonetella ------------ 313

Strophalosia ------------ 314

Daviesiella ------------ 317

Aulosteges ------------- 319

Ppoductus --------.... 321

Froductella .--.--.----1 328

Proboscidella ----------- 333

Etheridgixa .----------. 335

Supplementary Note on the Genus Obolus ------ 337

Descriptions of New Species - - -- - - - - - - 340

INDEX ---------- 356

PREFACE

The completion of the present volume is a partial fulfillment of a, promise
made at the close of Volume IV of the Palseontology of New York, in 18()7. Tlie
work is presented to the student with a hope that it may prove a useful con-
tribution to science and a helpful guide in the study of that most abundant and
most important class of Palseozoic fossils, the Brachiopoda. Originally intended
to form a supplementary part of Volume IV, the subject has expanded to such
an extent that two volumes will be required to present the results with a
reasonable degree of completeness ; and even with this addition some very
important matter, as the microscopic shell structure, originally intended for
the work, will have to be omitted from these volumes. •

The study of the Brachiopoda made necessary in the preparation of Volumes
III and IV, and more especially in the latter, had shown the necessity of sub-
dividing many of the older recognized genera, which had become the i-eceptacle
for forms having external similarity to the typical members of the several groups,
but possessing quite dissimilar internal features. The natural disinclination to
propose new generic terms for members of a class of fossils which had been so
widely and thoroughly studied in Europe, operated as a restriction in the
erection of new names However it became necessary to describe in those
volumes and in cotemporary papers some thirty-one new generic forms and
to suggest the necessity for farther separation among other heterogeneous
assemblages. These studies, made with fairly good collections, and ranging
through the Silurian and Devonian faunas, could not fail to attract
attention to the different external aspects and interior characters of
forms known under the same generic terms, and considered as distri-
buted through all the Palaeozoic formations. Although the genera thus
far proposed had not been based upon a recognition of their appearance and
duration in geological time, yet the student could not fail to discover evidences

X PREFACE.

of organic change in this direction. While discussing certain generic and
specific forms as characterizing known geological horizons or certain groups of
strata, we had not yet taken into consideration the fact that modifications of
organic types had been coincident with every change or progress in geological
time. The great law of progress through long intervals had been everywhere
recognized in geological science, but just how or in what manner these changes
liad supervened had rarely been shown in detail. Certain fossil genera have
Ion"- since been recognized as Silurian, others as Devonian, and others as
Carboniferous, but these are never entirely restricted to the formations which
they are said to characterize. They have all doubtless been derived from
some remote progenitor, and at certain horizons, or throughout certain forma-
tions have become so abundant and so fully developed, that they are said to
characterize that stage or formation. The most abundant and extravagant
forms among fossil organisms can usually be traced to some parent stock of
more modest pretensions, and in their early appearance, represented by few
individuals.

As stated, the studies of the Brachiopoda to the close of Volume IV of the
Palaeontology had shown the importance of some investigation which should
deal directly with these questions. And moreover the science demanded the
results of such an investigation in aid of its future progress.

The original conception and plan of the work which the author had
proposed to himself was a very simple one, viz.: to select the earliest
representative of a genus in any of the geological formations and to follow it
through all its manifestations and modifications in geological time, to its final
disappearance ; or so far as these modifications should appear in the Palaeozoic
rocks, to which he had limited his research.* With the knowledge then
possessed and with the collections at his disposal he had supposed that the
result of such an investigation could be embraced in a supplementary part to
Volume IV, and under this title the work was announced. This study was
commenced very soon after the publication of that volume and its general plan

*The (lirticnlty of iirocuiin-,' .«iifficifintly abuiifliiiit and characloi-istic collections of the latei- forma-
tions was in itself a sufficient baiTiei-, and the -scope of the woik did not contemplate the discussion of
Mesozoic and later genera, except in an incidental manner.

PREFACE. xi

was carried out so fixr as the lithographing of about thirty plates, when tlie
farther progress of the work was suspended, to be resumed onl}^ in the latter
part of 1888.

In the meantime the duties of the author had separated him almost entirely
from this work, and owing to changes, over which he liad no (lontrol, in
the organization and management of the State Museum, the collections which
he had planned to make for use in its preparation had not been made. The
progress in our current knowledge of the subject, and that recorded in the
publication of volumes and miscellaneous papers during more than twenty
years had been enormous, and the undertaking which had been deemed feasible
in 1867, seemed almost beyond attainment in 1888. The work was resumed
however, with no other collections immediatelj^ available for use, than those
upon which it had been commenced. In the original plan four plates were left
for the illustration of the Inarticulata ; the present volume furnishes ten
additional plates, and the illustrations of these forms may be regarded as fairly
complete, according to our present knowledge.

The plates which were lithographed at the commencement of the work are
designated on the upper left-hand margin as " Volume IV, Part II." Those
lithographed since 1888 are designated as Volume VIII, and while the illustra-
tions of the first named plates are not always arranged as would have been
done with later knowledge and more abundant material, it is hoped that the
intercalation of the new plates may not seriously interfere with the proper
connection and contiimity of the work, or with the facility of reference so
important to the student. Although the final numbering is XX, the actual
number of plates in the volume is forty-two.

The printing of this volume had been completed to the end of the
Inarticulata, page 183, in March, 1890, when farther progress was suspended,
from causes over which the author had no control. The printing was resumed
in the autumn of 1890, and the book was in type to page 304 in February, 1891,
when its progress Avas again suspended to be resumed only in April, 1892.
This delay in publication, which has not in any way been due to the author,
requires an apology to the scientific public ; and those authors who may have

xii PREFACE.

puMished papers relating to tlie Brachiopoda, during 1890 or 1891 which could
not be cited in this volume, will here find the explanation.

At the time this work was commenced the earliest known articulate
Brachiopod had been described under the name of Orthis, and without having
the knowledge or means to verify or disprove the character of this fossil, the
genus Orthis was adopted for the basis of discussion. Had these older forms
been better known, the order of the work might have been somewhat modified.
The other associated and succeeding genera have been taken up and treated
after the same idea as in Orthis; limiting the discussion to those which seem
to be a natural result of the modification of certain essential organic features
characterizing the earliest forms of the orthoid type.

Following this order and method we pass through all the Orthidje, the
strophemenoid and streptorhynchoid forms in their varied aspect and modifi-
cation, and through the leptaenoid forms to Chonetes and the Productidm
proper, with which the series seems naturally to end.

All tlie spire-bearing forms, all the Rhynchoneludm and Pentamerwm as
well as the terebratuloid forms have been left out of consideration in the present
volume, believing that a more natural and useful classification will be found in
the present adopted order and arrangement of the genera. Chapters upon
the classification and broader relations of the genera are given at the
conclusion of the two principal divisions of the work. The succeeding
part ii of volume VIII will embrace the discussion of the genera under the
several groups just mentioned, and the}^ will be treated essentially in the same
manner as in the present volume. The work on the second part is already far
advanced ; a large amount of material has been accumulated for study ; thirty-
si, \ plates have been lithographed, a considerable number of drawings have
been made and a large amount of manuscript has been prepared.

During the interval of more than twenty years from its commencement,
great progress has been made in the study of both genera and species of the
Brachiopoda. The late Thomas Davidson, LL. D., of Brighton, whose life had
been devoted to the study of these organisms, living and extinct, made important
contributions to our knowledge up to the time of his death in 1885. Essays

PREFACE. xiii

toward the structure and classification of the genera were made by Zittel,
ffinLERT and Waagen, and communications of no little importance relating to
structural characters of genera and species, appeared from all quarters of the
scientific world.

The multiplicit}' of these communications is indicated in part hy the biblio-
graphic tables presented in this volume ; they also show the wide-spread inter-
est in the Brachiopoda, not only among students of biology, in their structure,
morphology and taxonomy, but among geologists, in their value as stratigraph-
ical indices. American students have heretofore labored under a disadvantage
in the irregular diffusion of the literature of the Brachiopoda. Much of the
European literature is inaccessible except to those working in the vicinity of
extensive libraries; the American literature is so scattered through scientific
periodicals, proceedings of various societies, etc., as to be frequently inaccessible.
Furthermore, while the more general treatises of Zittel and (Ehlert may be
in the hands of many, the gi'eatest of all works upon the subject, that of Thomas
Davidson, is beyond the reach of but a very few.

With this volume, therefore, is presented, especially to American students, the
first part of "An Introduction to the Study of the Genera of the Palaeozoic
Brachiopoda," a work not conceived upon the plan of any of its predecessors,
but designed to set before the student the present condition of our knowledge
of these genera, with such discussions and illustration as will serve most
clearly to indicate what progress has been made in our knowledge of these
organisms and in what directions much still remains to be done.

In the preparation of this work every effort has been made to bring under
close and careful scrutiny all obtainable material representing the Brachiopoda.
The collections of no single institution or individual could furnish the speci-
mens requisite for this undertaking, and recourse has been had to all sources of
material within reach. The collections of private individuals as well as of
public institutions have been placed at the disposal of the work, and but for
such aid it could not have been presented in a creditable form.

My acknowledgments are especially due to Sir William Dawson, Principal
of McGill University, Montreal, Canada, for specimens and valuable informa-

XIV

PREFACE.

tion ; to Mr. G. F. Matthew, of St. John, N. B., for the use of fossils of the St.
John group, and for valuable information concerning them ; to Hon. A. R.
C. Selwyn, Director, and to Mr. J. P. Whitewes, Palaeontologist, for the use
of many typical specimens from the Museum of the Geological Survey of
Canada. Also to Mr. W. K. Billings, of the Department of Public Works,
Ottawa, Canada, and Mr. H. M. Ami, of the Geological Survey.

From Mr. Thomas A. Greene, of Milwaukee, Wisconsin, I have received
most important material from the Niagara group of Wisconsin; from Dr. Josua
LiNDAHL, Curator, and from the Trustees of the Illinois Museum of Natural
History, the free use of its collections; from Prof C. L. Herrick, of Chicago,
the use of his typical collection of the Waverly group ; from Prof. James M.
Safkord, of Nashville, Tenn., interesting material from his collections which
have been utilized in the illustration of the Orthwje. To Prof J. S. Newberry,
I am indebted for the free use of his very interesting collections, especially of
the Carboniferous fossils ; to Prof Edwaru Orton, for his liberality in permit-
ting the free access to the collections of the Geological Survey of State of Ohio;
to Prof G. C. Broadhead, of the University of Missouri, for the use of many in-
teresting forms of Carboniferous fossils ; to Rev. John Bennett, of Kansas City,
for the use of very interesting Coal Measure fossils, especially of the genera
Derbva and Enteletes ; to Prof. Samuel Calvin, of the University of Iowa, for
his liberal aid toward the illustration of the Silurian and Devonian Brachiopoda
of Iowa; to W. C. Egan, of Chicago, for the use of some interesting forms of
Carboniferous fossils, and to Dr. C. Rominger for his liberal and intelligent con-
tributions to our knowledge and means of illustration of the Brachiopoda, an
obligation beginning as far back as 1863.

From the American Museum of Natural History, through Prof. R. P.
Whitfield, .specimens representing many genera and the types of many species
have been received ; from Prof J. P. Lesley, State Geologist of Pennsylvania,
a series of inarticulate Brachiopods from that State; from Mr. Charles D.
Walcott the use of specimens and information concerning the same; from Prof.
James R. Eaton, of William Jewell College, Missouri, during many years, the
use of specimens and for much intelligent information ; from Rev. H. Herzer, the

PREFACE. XV

use of some interesting^ specimens of recent collection and information concern-
ing certain horizons in the Lower Carboniferous strata, and also the abundant ma-
terial of his earlier collection ; from Prof E. W. Claypole, the use of specimens,
as well as information concerning the geological relations of certain species ;
from Pres. E. S. Brainerd and Prof H. M. Seely, of Middlebury College, Vt.,
the use of specimens from the Calciferous horizon, which have since been
donated to the State Museum ; from Prof Geo. H. Perkins, of the University
of Vermont, the use of specimens ; from E. E. Teller, of Milwaukee, Wis.,
and F. A. Sampson, of Sedalia, Mo., similar favors. Acknowledgments are
further due to Mr. F. A. Blair, of Sedalia, M*^, and Dr. J. H. Britts,
of Clinton, Mo., for the use ol' specimens and especially for a collection
of Choteau limestone fossils from the former; also to W. H. 11. Lyicens,
S. J. Hare, F. W. McIntosh, of Kansas City, for specimens of Coal Meas-
ure fossils ; also to Prof Thomas B. Stowell, of Cortland (now of Potsdam),
N. Y., W. L. Brownell and D. S. Chatfield, of Syracuse, and E. B. Knapp, of
Skaneateles. To Prof B. K. Emerson, of Amherst, Mass. ; to Dr. C. E.
Beecher, of New Haven, Conn.; and to E. 0. Ulrich, of Newport, Ky., thanks
are due for specimens and information ; also to W. T. Knott, of Lebanon, and
Mr. E. C. Went, of Frankfort, Ky.; to Prof William Libbey, of Princeton, N. J.,
through MoRiTZ Fischer; Prof Joseph Moore, of Earlham College, Richmond,
Ind. ; to Col. C. C. Grant, an old and valued correspondent, and Mr. William
TuRNBULL, of Hamilton, Ontario, and to Mr. B. E. Walker, of Toronto, for speci-
mens from the Niagara and Hudson River groups ; to Professors Oliver Marcy,
of Evanston, 111., Edward M. Sheparu, of Springfield, Mo., W. H Barris, "of
Davenport, la., and S. S. Gorby, State Geologist of Indiana ; to L. A. Cox and
D. G. Anderson, of Keokuk, la., for brachiopods of the Keokuk group, presented
by them to the State Museum ; to R. R. Rowley, of CurryX'ille, Mo.; to Miss
Mary E. Holmes, of Rockford, Victor E. Phillips, of Olney, and J. H. South-
well, of Rock Island, and to W. R. Head, H. H. Hindshaw, and Victor C.
Alderson, of Chicago, Illinois.

Among foreign friends and correspondents, my first acknowledgments are due
to the late Thomas Davidson, of Brighton, England, for many years of personal

^,,i PREFACE.

friendsliip a.ul intiniiite correspondence relating to scientific questions, and
especially to the Brachiopoda. The pages and illustration of this volume will
bear testimony to the knowledge derived from this eminent source. Also to
Dr. Th. Tschernyschew and Dr. Fr. Schmidt, of St. Petersburg, Russia; to
Prof. E. Kaysee, of Marburg, Germany ; to Miss Agnes Crane, of Brighton,
England : Dr. D. P. ffinLERT, of Laval, and Prof. Charles Barrois, of Lille,
Friuice ; to Dr. G. Lindstr()M, of Stockholm, Sweden, and to Mr. John Young,
of Glasgow, Scotland, acknowledgments are especially due.

The lithographic plates accompanying this work have been drawn on stone
by Mr. Philip Ast, whose accurate and artistic execution of similar work is
already known to the students of these volumes. The original drawings of the
earlier plates were mostly made by Mr. R. P. Whitfield and the late Mr. F. B.
Meek ; the drawings for the later plates was begun by Mr. E. Emmons, whose
services were subsequently supplemented by the skillful and beautiful work of
Mr. George B. Simpson.

To Mr. Charles Schuchert, my private assistant, this volume owes much.
His critical knowledge of the species of American Brachiopoda, and his famil-
iarity with the literature pertaining to them, as well as his unequaled collec-
tion of fossil Brachiopoda, have all been placed at the disposal of the work with
the devotion characteristic of the student. To him is due the fullness of the
bibliographic tables, which afford virtually a complete summary of American
literature upon these genera.

To Prof. John M. Clarke, Assistant Palaeontologist, I am especially indebted
for his faithful and appreciative devotion to the accomplishment of this under-
taking. On the resumption of this work in 1888, Mr. Clarke was appointed
my official assistant, and he entered at once into sympathy with my plan, and
became an enthusiast in the study of the Brachiopoda. To him I am indebted
for carrying out in its details, the spirit of my conception to a degree of com-
pletion which I had not anticipated.

JAMES HALL,
Albany, May, 1892. State Geologist and PalcRontologist.

I N T R O D U C r 1 () N

STUDY OF THE GENERA OF THE PALEOZOIC BRACHIOPODA.

I.

BRACHIOPODA INARTICULATA.

Valves inarticulated ; intestine terminating in an anus on one side of the body ; shell

substance largelij phosphatic.

The foregoing characters bring into association a well defined assemblage of
these organisms, but, while generally applicable throughout the group in ex-
pressing the fundamental distinctions from the more abundantly developed
Brachiopoda Articulata, there often appear, in forms which cannot be separated
from such association, tendencies to transgress these limitations in various
directions. For example, articulation of the valves was approached, if not
effected, in the linguloid Barroisella, in Spondylobolus, and, perhaps also, in
Neobolus and Trimerella. In Crania, according to the determination of
JouBiN,* the anus opens in the median line of the body; and in various genera.
Crania, Pholidops, Trimerella, etc., there is evidence that the substance of the
shell was essentially, or altogether calcareous.

We have preferred to adopt for this division of the Brachiopods, Professor
HoxLEv'sf term, Inarticulata, which has the advantage of euphony and sim-
plicity. Other writers have made use of terms with different significations, all

* See xmder genus Crania.

t An Inli-oduction to the Classification of Animals, [>. 116. 1869.

2 PALEONTOLOGY OF NEW YORK.

having precisely the same scope. Professor Owen * in 1858, proposed the term
Lyopomata (;,,-a. and ™,:a), essentially the Greek equivalent of Inarticulata,
and of BaoNN'st Ecardines. The last named author also suggested the term
Plecropygia, derived from the lateral position of the intestinal perforation ;
while King's term, Tretenterata,^ indicates that the existence of an anus is
to !)(' regarded as the essential character.

The use of Family designations in this group Avould be attended by embar-
rassments so serious, that it has seemed preferable to avoid them altogether.
The present state of our knowledge fully justifies this position.

Genus L I N G U L A, Bruguiere. 1789.

PLATE I, FIGS. 1-31; AND I'LATE IV K, FIGS. 5-13.

1789. Lingula.§ BudguiIsbi!. Hisl. Natur. des Vf^rs Testaces.
1798. Pharetra, Boltkn. Mus. Boll.
1806. Lingularius, Dum^ril. Zoologie Analytique.
Lhiffula, of authors generally.

{ Oloss'iva, Phillips, 1848. Mem. fii'ol. Sui-v. Great, Britain, vol. ii, pfc. 2, p. 370.
-j Cflottidia, D.vll, 1870. Amerii'an Journal of Conchology, vol. vi, p. 157.
|_ Z>i(/«<wfti'a, II.\LL. 1871. Imjicrfec'tly known Forms .among the Brachiopoda.

18H9. Linc/ula, Coxhad. Second Ann. Rept. PahTont. Dept. N. Y. State Geol. Surv.

1842. Linyuhi, Va.niixbm. Geology N. Y., Rept. Third Di.sti-ii'.t.

1842. Lingula, Em.mons. Geology N. Y., Rejit. Second District.

1842. Lingula, Co.nhad. .loui'. Acad. Nat. Sci. Phila.

1843. Lingula, Hall. Geology N. Y., Rept. Fourth District.

1844. Lingula, Owk.v. Geol. Rept. Iowa, Wi.scxm.sin, and Illinois.
1847. Lingula, Hall. P.alfeontology N. Y.., vol. i.

1847. Lingula, Dana. American Journal of Science.

1851. Lingula, Hall. Foster .and Whitney's Rejit. Geol. Lake Superior.

1852. Lingula, Hall. Palaeontology N. Y., vol. ii.

1852. Lingula, Owu.s. Geol. Rept. Iowa, Wisconsin, and Mirmesota.
1852. Lingtda. F. Rosmkr. Kreidehildung von Texas.

* Enciyclopredia Brilannica, Sth Ed., vol. xv, p. 301.

t Die Chissen and Ordnungcn des Thierreichs, p. 301. 18tJ2.

J Annals and Magazine of Natui'al Histoi'y, vol. xii, p. 15. 1873.

§ The synonymic li.sts accompanying these discussions are intended to give, first, the more important
names under which the genera have been mentioned Uy Euiopean and American writers, followed by a
table of references to notices in American literature of the gener.a or their species. Under the lesser groups,
the list.s are not thus divided, but will be found to contain all the imporlaut references necessary for the use
of the student.

BRACHIOPODA.

1856. Liiiffula, Billings. Canadian Naturalist anil Geologist.

1856. Lingula, Em.mons. American Geology.

1857. Lingula, Cox. Geological Survey of Kentucky, vol. iii.

1858. Lingula, Meek and Hatdek. Proc. Acad. Nat. Sci. Phila.

1858. Lingula, Suc.mard. Tran.s. St. Louis Acaileniy of Sciences.
I85i1. Lingula, Billings. Canadian Naturali.st and Geologist.

1859. Lingula, Hall. PaUeontology N. Y., vol. iii.

1S60. Lingula, Hall. Thirteenth Rept. N. Y. Statf Cab. Nat. Hist.

1861. Lingula, Billikgs. Canadian Naturalist and Geologist.

1862. Lingula, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist.
1862. Lingula, Billings. Paleozoic Fossils, vol. i.

1862. Lingula, Whitb. Proc. Boston Soc. Nat. Hist.

1S63. Lingtda, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist.

1863. Lingula, Hall. Trans. Albany Institute.

1863. Lingula, Winchell. Proc. Acad. Nat. Si;i. Phila.

1865. Lingula, White. Proc. Boston Soc. Nat. Hist.

1865. Lingula, Billings. Palneozoic Fossils, vol. i.

1866. Lingula, Billings. Catalogue Sihii-ian Fossils Anticosti.

1867. Lingula, Hall. Palaeontology N. Y., vol. iv.

1868. Lingula, Meek. Trans. Chicago Academy of Sciences.

1868. Lingula, Meek and Worthbn. Geological Sui-vey Illinois, vol. iii.
1S69(?) Lingula, Winchell. Proc. American Philosophical Society.

1872. Lingula, Meek. Rept. Palseontology Eastern Nebraska.

1873. Lingula, Hall. Twenty-third Rept. N. Y. State Cab. Nat. Hi.st.

1873. Lingula, Meek and Wortuen. Geological Survey Illinois, vol. v.

1874. Lingula, Ratubcx. Bull. Buffalo Soc. Nat. Hist.
1874. Lingula, White. Wheeler's Exjil. 100th Meridian.

1874. Lingula, Billings. Palaeozoic Fossils, vol. ii.

1875. Lingula. Nicholson. Rept. Palaeontology Province of Ontario.
1875. Lingula, Meek. Geological Survey Ohio ; Palaeontology, vol. ii.
1875. Lingula, James. Cincinnati Quart. Journ. Science.

1875. Lingula, Hall and Whitfield. Geological Survey Ohio ; Palaeontology, vol. ii.

1875. Lingula, S. A. Miller. Cincinnati Quart. Journ. Science.

1878. Lingula, Rathedn. Proc. Boston Soc. Nat. Hist.

1879. Lingula, Emerson. GpoI. Frobisher Bay, in Nourse's Narr. Hall's Arctic Expedition.

1879. Lingula, Hall. Descrip. Neve Spec. Fossils from the Niagara Group.

1880. Lingula, N. H. Winchell. Geological Survey Minn., Eighth Ann. Rept.

1880. Lingula, Whitfield. American Journal of Science.

1881. Lingula, Hall. Eleventh Ann. Rept. State Geologist Indiana.

1882. Lingula, Whitfield. Geology Wisconsin, vol. iv.

1884. Lingula. H. S. Williams. Bull. No. 3, U. S. Geological Survey.

1884. Lingula, White. Thirteenth Ann. Rept. State Geologist Indiana.

1884. Lingula, Worthbn. Bull. No. 2, Ilhnois State Mus. Nat. Hist.

1884. Lingula, Walcott. Palaeontology Eureka District.
18S4. Lingula, Ringuebbrg. Proc. Acad. Nat. Sci. Phila.

1885. Lingula, Clarke. Bull. No. 16, U. S. Geological Survey.

1887. Lingula. Whitkaves. Geo!, and Nat. Hist. Surv. Canada.

1888. Lingula, Herrick. Bull. Denison Univ., vol. iv, pt. 1.

1889. Lingula, Walcott. Proceedings of United States National Museum 1888.
1889. Lingula, Nettelroth. Kentucky Fossil Shells.

PAUEONTOLOGY OF NEW YORK.

beaks of the two

Diagnosis. Shells sub-equivalve, equilateral; elongate-ovate, sub-quadrate
or 8ub-triangular in outline ; broad over the pallial region, cardinal slopes more
or less conspicuous ; slightly gaping at both extremities. Brachial or dorsal
valve someu-hat the shorter, and with a slightly thickened hinge-line. Surface
of the shell smooth, or concentrically and radiately striated. Animal attached
by a long, muscular pedicle protruding from between the
valves.

Muscular impressions numerous, but usually in-
distinct. In the recent species they are twelve
in number upon each valve, and are somewhat
unsymmetrical in their arrangement. Tliey may
be designated as follows : The umbonal impressions
(g), produced by a single muscular band passing
directly across the cavity of the shell near the
beaks, (ind by their contraction opening the valves;
the lateral impressions, which are produced by
three pairs of muscles, the anteriors {j) passing
from near the lateral boundaries of the visceral
area on the pedicle-valve, forward to the anterior
extremity of this tract on the brachial valve ; the
middles (k) passing in just the opposite direction,
from the anterior region of the pedicle-valve to
the lateral region of the brachial ; the externals
(l) passing from the ante-lateral region of the
pedicle-valve to the post-lateral regiou of tlie
brachial valve, these muscles serving to move the
valves forward and backward. Tlie central impres-
sions (A) are produced by a single pair of muscles extending across the ante-
lateral region of the visceral area, and b}^ the contraction of these, the valves are
closed. The transmedian impressions (z), are made by a triple muscle, one band
of which i.s on one side the visceral area, the other two on the other side, the
two lateral components crossing each other in passing from the posterior region

KiG. ]. T.ini/ula anatina, after HANCOCK.
;*, pedicle ; g, uinboiiMl muscle ; h, cen-
trals ; /, transniedians;,/, A:, Z, laterals (.7,
anleriors, *, middles, 2, externals); e, heart;
o, moulh; a, al'iuGntary canal ; «, anus.

BRACHIOPODA. 5

of the pedicle-valve to the medio-lateral region of the opposite valve. By the
action of these muscles the animal is able to slide apart the anterioi' and
posterior extremities of its valves * The muscular region in each valve is sur-
rounded by the parietal bands (/»), which leave more or less distinct impressions
upon the shell.

The anterior internal surfiice of eacli valve bears traces of two strong pallial
sinuses, which nearly meet in the axial line before reaching the anterior margin.
In front and Itehind are radiating vascular markings.

Shell substance composed of alternating lamellae of chitinous and calcareous
material.

Type, Livgula analina, Lamarck.

Observations. Few of the larger genera of the brachiopoda form so integral
a group and present so well defined limitations as the genus Lingiil.\. Not-
withstanding, however, the compactness of the genus, the discrimination of
palieozoic species is frequently attended by very great embarrassments, arising
from the tenuity of the shell, its liability to distortion in process of fossilization,
the general similarity in the matter of external ornamentation, and the usual
obliteration of the definition of the muscular scars by maceration or I'rom the
character of the matri.x.

Primarily, the shells of paheozoic Lingulas present two extremes of varia-
tion in outline, (a) an acuminate or sub-triangular form, in which the rostral
area is very narrow, with long, .sloping post-lateral margins, and a rounded or
transverse anterior margin ; (b) a sub-quadrate form, with the posterior or
rostral margins converging toward the beak. The passage-forms between these
extremes present outlines varying from ovate to elliptical, and here the great
majority of species is to be assigned. While all these variations in form have
maintained a contemporaneous existence in palaeozoic time, the acuminate type
(a), prevailed both numerically and specifically in the earlier faunas {L., acumi-
nata, in the Calciferous sandstone ; L. attenuata, in the Llandeilo ; L. crumena, in

* Among- authois thei-e has been a confusing variety of nomenclature foi- the muscular system in
LiNGULA. The one that is useil here is proposed by Professor William Kino, anil, in its simplicity, has
claims for adoption.

6 PALEONTOLOGY OF NEW YORK.

the Llandovery ; L. Daphne, L. ricinifnrmis, in the Trenton ; L. Rouaulti, L.
Hawkii, in the Budleigh-Salterton pebbles [Lower Silurian] ; L. perovata, in the
Clinton: L. cuneata, in the Medina sandstone; L. spatiosa, in the Lower
Helderberg), diminishing during the Devonian (L. Lecena, in the Hamilton),
and reaching the close of the Palaeozoic with a very meager representation
(L. Scotica, L. flabellula, in the Carboniferous); and of the various types of
outline, this is the only one not represented among living species of the

genus.

The generic'term Lingula, like many other names among the fossil brachi-
opods, has long been a receptacle for various fossils, which, in the absence
of linowledge of their internal characters, have been assumed to be con-
creneric. Recent observers have, however, made great progress toward a cor-
rect understanding and limitation of the group. Many species of acuminate
form originally referred to Lingula, have been found to difier so distinctively,
in essential features, from the type species, L. anatina, that the erection of
various other generic groups has been necessary; e. g., Lingulella, Salter, LiN-
GULEPis, Hall, Glossina, Phillips, etc. To some of these newer genera, probably
belong most of the species from the primordial faunas, which have Ijeen
described as " Lingula," a doubt resting upon all the species thus referred,
whose interior markings are not known. Thus, L. ampla, Owen, L. Winona, and
L. Mosia, Hall, from the Potsdam sandstone of Wisconsin, have the external
characters of Lingula, and must, of necessity, be regarded as members of the
genus, until the difference has been demonstrated from internal characters.
Likewise, in the British primordial faunas are the species, L. squamosa, HoU,
L. pygmcea, Salter, and L. petalon, Hicks, of which we have still to learn the
true generic relations. The fact that as far as the internal characters of
the species of the earliest faunas have become known they have shown generic
differences from Lingula, may, to a certain degree, justify the temporary refer-
ence of the species mentioned to some other group.

This genus has been most remarkable for its wonderful adaptability to change
in the conditions of life through immeasurable lengths of geological time, and,
though in its strict limitation it may not have been represented in the earliest

BRACHIOPODA. 7

faunas appearing on the earth, its persistence in time is nevertheless unequaled
by that of any oilier known genus of organisms.

The palaeozoic Lingulas, sensu strido, have not shown variations of sullicient
importance to permit a thoroughly satisfactory subdivision of the genus. As
the interiors and muscular scars of different species become known, they re-
veal a closer alliance with one another, and with the recent type of the genus,
than had been suspected.

There is a growing tendency among authors to remove certain species from
this genus to Lingulella on account of an apparent inequality in the valves of
the shell, accompanied by a cardinal area on the pedicle-valve, which seems
to be grooved or depressed from the apex forward. Great care is needed in the
accurate determination of these features. The type species, Lingula anatina,
has not only gaping and slightly unequal valves, but the pedicle-valve has a
distinct cardinal shelf or area, divided longitudinally by a depression widening
from the apex anteriorly, and termed by Ktxg* the " deltidium." This, accord-
ing to Professor King, is usually not well developed, and in the average speci-
mens of L. anatina found in museum collections, ap- j<^
pears to be partially or quite wanting, from accidental ^' "^^ ^^\.
causes. The deltidium is bounded at the sides by ^""j^^/ S^^^^v
elevated ridges, which, at the anterior ends, are each ^;^3^^^^^^^^^^^-^^
developed into a small callosity. "The ridge-callosi- ^lo. 2. xi«<7«;aana«,m,-c.-.niinaiarea

,. 1 1 .*••/* i. ii 1 xu of pedicle-vaUe, alter King, a, del-

ties are no doubt nisignifacant; nevertheless they tidiuni;6,.ieitidiaiii.jgc8;c,cieuidiai

,1,1 T , ,. • , J i. i callosities ; rf, areal borders.

appear to be the rudmients 01 important structures.

Apparently they have become so far developed in Lingula Lesmuri, as to serve

to articulate the valves. If I am correct this species cannot

belong to the genus in which it has been placed."! In the opposite or brachial
valve is a slight area without a deltidium, but bearing concentric growth-lines,
and a very faint longitudinal groove.

It is to be expected that we shall find similar features more or less devel-
oped among the fossil Lingulas. The broad, depressed deltidium of L. anatina

* Anuals and Magazine of Natural History, July, 1873.
t King, loe. cit., p. 13.

8 PALAEONTOLOGY OF NEW YORK. ■

is not to be confounded with the deep pedicle-slit in Lingulella. Furthermore,
a slight longitudinal displacement of the valves before, or while undergoing
fossilization, will frequently exaggerate the normal extension of the umbonal
region in the pedicle-valve, beyond that in the opposite valve. We are dis-
posed to consider the current reference to Lingulella of several well-known
American species, e. g., L. lowensis, Owen,* L. Covin gtonensis, Hall and Whit-
field,t L. Norwoodi,X James, L. Vanhornii, Miller, as incautious, and feel that,
in general, these are more safely left under the original genus. Two of the
species named, viz., L. lowensis -and L. Vanhornii,
have muscular impressions comparable with those
of L. anatina, and of widely different character and
arrangement from those in the genus Lingulella,
Living Lingulas, are known to form a tube about the
pedicle by the agglutination of grains of sand or other
sedimentary debris, after the manner of Tubifex and
other forms of Chtietopod Annelids. (See accompany-
ing figure o[ Lingula pyramidata,\ Stimpson, after Morse,
which shows this tube, as well as the effect of the
action of the sliding or iransmedian muscles in swinging
the valves laterally asunder.) no. 3. uiioid,nGiottma)Andebarti.

After MOKSE.

* Lingulella loicejisis, Whitfield, Geol. Wisconsin, vol. iv, i>. 242. 1883.

t Mr. S. A. Mii.i.ER, in his " Catalogue of the Fo.ssil.s foumi in th(! Hudson Rivei', Utica Slate and Trenton
Groups, as exposed in the South-ea.'st part of Indiana, Sonth-we.st part, of Ohio, and Noi-lhem p.-irt of Ken-
tucky"; Tenth Ann. Kept. Geol. Surv. Indiana, says, on page 19, under the heading Lingula : " All the
species referred to this {;enus" [in the groups mentioned] "Leiong to LmgnleUa ; " and in Mr. J. F. Jamks'
"Catalogue of the Fossils of the Cincinnati group," 1881, in addition to the species mentioned above (ex-
cepting L. Conngtonensi.s), L. attenuala, SmverUy. and f,. i-iciiiifiiriiiin. Hall, are refei-i-ed to the xuh-ije-iiiis

Ll.MiCLELLA.

■ t 'ITiis species belongs to the genus Linoitlops.

§ Cflottidia Audtbarti, Broderip. Davidso.n, Ti-;uis. Linnoan Society, Scicond Ser., Zoology, vol. iv. )iart
3. p. 223.

BRACHIOPODA.

TJnyuld ii.quiili.i, UM. I.iiujuUi ? LcsueuH, Itouault.

Willi peilii'lo. With pellicle.

Alter Walcott. Al'lev Davuisox.

The retention, in tlie fossil state, of tlie pedicle, is a rare occurrence. Of
palaeozoic species, Mr. Davidson* has figured
an example of />. ? Lesuewi, in which the
impression of this organ is very distinctly
shown. More recently, Mr. Walcott f has
described a beautiful example of L. iRifualis,
Hall, in which the narrow arm is seen pro-
truding from the aperture in the cardinal
area. By the favor of Dr. J. S. Newberry,
we have been allowed to figure a specimen
from the Waverly sandstone at Oil City,
Penna. (see Plate IV k, fig. 7), in which the
pedicle is also distinctly visible. The species
is the one identified as L. Scolica, Davidson,
by the Ohio geologists, and more recently described by Mr. HerrickI as L.
Waverliensis.

In regard to tlie myology of the palaeozoic Lingulas, we have satisfactory
evidence tliat the arrangement of the muscles did not differ widely from that
in recent members of the genus. It is, however, not often that a palseozoic
specimen is found which has retained upon the surfoce of the shell, or left upon
the matrix, traces of the delicate muscular scars; and in such instances usually
only the stronger impressions are discernible. A few examples have been figured
by recent American writers, which retain, in exquisite detail, not only the mus-
cular, but also the pallial impressions of the shell. Of these, one is a brachial
valve of the L. Whitii, of Walcott, figured in his Palaeontology of the Eureka
District ;§ another, an internal cast, representing the impressions on both dorsal
and ventral valves of L. Elded, Whitfield, figured by the author first, in the Amer-
ican Journal of Science,|| and subsequently, in the Report of the Geological Survey

* Bi-achiopotla of the Budleigh-Saltertoii Pebble-bed, p. 362, pL xl, tigf. 16.
t Proceedings of the United States National Museum, for 18S8, p. 4S0, (\g. 3.
X Bull. Uenison Univ., vol. iv, pt. 1, p. IS, pi. iii, tier. 1. 1S88.
§ Paye 109, pi. xiii, fig-. 3, and pi. xxi, fig. 19. 1S84.
II Vol. xix, p. 473. 1880.

10

PAL/EONTOLOGY OF NEW YORK.

of Wisconsin.* Upon the first plate of this volume are given, in addition to
copies of the figures named, a number of illustrations representing these impres-
sions in different degrees of completeness ; especial attention may be directed
to the figures of L. punctata, L. Procten, L. densa, and to those of L. lamellata,
upon Plate IV k. (See, also, the figures of L. Lewisi, Sow., given by Davidson,!
and the accompanying text illustrations of extremely well preserved internal
casts of L. Melie [brachial valve], and L. paradetus, sp nov. [pedicle-valve].)

There has been a considerable diversity of opinion among authors, in regard
to the special functions of the various muscular bands in Lingula. Few in-
vestigators have brought to the study of this subject the clear insight and
incisive judgment of Professor AVilliam King, whose nomenclature of the mus-
cles, we have preferred to adopt.

The first strong impression arising from the comparison of these ancient forms
with tiie type-species is that in the former, the dorsal scars of the central muscles (A)
are relatively much the larger, and
are situated somewhat posteriorly,
apparently encroaching upon that
portion of the visceral chamber
which, in L. anatina, is occupied
by the essential organs of the = =
animal. This apparently great ^ =
size, however, is somewhat illusory, rii
as undoubtedly a portion of these ^ =
large scars is due to their contin-
ued advance as the shell increases
in age, and probably at no time in
the mature life of the animal did
these muscular bands, at tiieir or- ^Mw^a «»«<««. after Davidson.

Fig. 6. Peiliclc-valvc, FIG. 7. t Brachinl valve.

Igm and insertion, COXCr the entire ^' P"''?'''' ^.'^-y ■ S~ umbonal muscle; », Uansmedians, h, centrals:
"^ i.*.'. '"lerals (J,anteriors; *, middles; J, externale).

* Vol. iv, i>. M:>, 1)1. xxvii, lig.-,. 3-5. 18S2.

t Moiioffr. Biilish Siluiian Biach., jjl. iii, '^gs. 5, 0.

: Dav.d.^o.v'.s Hgn.es are .lia-.-...miii.-iti<> copies of the more elaborate illustrations given by King. In the
process of coi.yin;r it is evi.lent that fi;.. 7 l,as been reverse,!, and the position of the double an,) single
muscular bands of (i) inverted.

BRACHIOPODA. 11

scars. Thesamemay be said of the other scars, all of which show something of this
progressive increase in size. The impressions which appear to be most gener-
ally retained among the fossils are the anterior laterals (j) of the brachial valve,
and the middle laterals (k) of the pedicle-valve. These lie in the ante-median
portion of the valves, and, in their progress forward, have left long, conspicu-
ous tracks which follow the axis of the shell.

The separate members of these pairs of impressions are not always, or even
often, to be distinguished, the long axial impression accompanied by the ante-
rior portions of the broad centrals being usually all that is visible of the mus-
cular scars. The subdivision and asymmetry of these scars in L. anatina has
been determined only by the aid of the attached muscular bands. Without their
assistance it would prove difficult, if not impracticable, to ascertain their exact
limitations, merely from the impressions upon the shells. This will, to a certain
degree, be made evident by comparing Professor King's figures with those of
the same species given on Plate I ; in the latter drawings the scars have been
somewhat emphasized, but it is impossible to resolve, with any degree of
accuracy, the compound lateral and transmedian scars {k, I, i, in the brachial, j, i,
in the pedicle-valve). Nevertheless, in the brachial valve of L. Wliitii, the com-
pound lateral scar is quite distinct, and the umbonal (g) impressiou well defined.
On the brachial valve of L. Elderi, Mr. Whitfield has shown the former to be
even more clearly defined than in L. Whitii, and the umbonal scar to be un-
usually large. In both these species, the laterals and transmedians are situated
considerably nearer the umbonal region than in L. anatina. The pedicle-valve
of I/. Eldei-i shows the transmedian scars, which are represented as two on each
side, the anterior of wdiich is regarded by the author as the scar of the
"posterior adjustors" (transmedian) and "anterior adductors" combined.
Lingula punctata shows comparatively broad muscular scars in this region, but
it has been impossible to resolve them satisfactorily. The umbonal scar also,
appears on the pedicle-valve of L. Elderi.

A species of Lingula from the Cuyahoga shale at Johnstown, Chardon, and
elsewhere in Ohio, which has usually been confounded with the common L. Melie

12

PALJEONTOLOGY OF NEW YORK.

.- -9

FIG

LittgiiUi paracletusi, sp. iiov
Interior of iiediclevalve.

KlG 9.

Lingula Mclie^ Hall.
Iiiterioi' of bracliial valve.

of these beds, but is described in
the concUiding pages of this work
as L. paracleius, sj). nov., has
afibrded the most complete and
satisfactory representation of tlie
system of muscular scars. The
pedicle-valve here figured is drawn
from a cast of the interior, wliicli
shows not only the centrals (h),
middle laterals (/c), but the dis-
tinctly specialized outside laterals
(/), anterior laterals (j), the transmedians (/), and the great umbonal (g).
Even the asymmetry of the transmedians (?) is apparent in the unequal
size of the impressions, that on the left in the figure (corresponding to the
right, when looking into the interior of the valve) being noticeably larger than
its correlate. In the brachial valve, the scars are essentially like those in the
corresponding valve of J.. Melie, shown in the accompanying figure, but are not
placed quite so far back. Here the laterals (/, k) and transmedians (i) are
coalesced, and show a tendency to spread transversely over the visceral region,
a feature sometimes noticeable in other palaeozoic species, and probably of
similar nature to that seen in Barroisella suhspalulata (Plate I, fig. 10).

As far as the vascular markings of the brachiocoele in the fossil species have
been observed, they appear to have been in full agreement with those of the
living type. In L. Whilii, L. Elderi, L. punctata, L. cuneata, and L. lamellata the
large pallial sinuses are to be seen passing forward from the parietal band, or
the position of the compound lateral scars, approaching each other until they
nearly or quite meet in front. The outer ramifications from these large trunks,
and, in L. Elderi and L. cuneata, the inner also, are discernible. In the brachial
valve of L. Elderi are seen the vascular impressions of the pleurocoeles, which
lie in the post-lateral portion of the internal cavity, outside the parietal
band. In L. Procteri and L. paracletus, the anterior vascular branches appear
to radiate from the edge of the central muscles, as though the pallial trunks

BRACHIOPODA. 13

passed closely about their insertion, a feature wliieli requires confirmatory
evidence.

In so far, then, as the impressions upon the shell, left by tiie soft parts of tlie
animal are concerned, we find a close correspondence in the existing and palae-
ozoic members of this genus.

We turn now to a consideration of the septal markings on the int(>ri<)r of tliese
shells. When the soft parts are entirely removed from the shell of y>. anatina,
the pedicle-valve shows a broad, low, longitudinal ridge, whose margins are
sharply incised along the posterior portion, but become elevated with tlie ele-
vation of the entire ridge anteriorly. This ridge terminates in front of the
center of the shell, and bears, at its excavate extremity, the impressions of the
middle-lateral muscles, being buttressed on either side behind these, by the large
scars of the centrals. From the posterior extension of this ridge diverge two
more or less distinct longitudinal callosities, which are the inner boundaries of
the transmedian impressions, or the raised margins of the parietal scars. In
the opposite, or brachial valve, a longitudinal ridge is more or less developed
toward the posterior portion of the shell, but becomes flattened over the
central visceral region, whence it is produced much further forward tiian in the
opposite valve, and is sharply elevated. Its terminal portion separates the ante-
rior lateral scars, directly behind them lying the central niusc'uiar impressions.
With these features in mind, we must expect to find the true paliBozoic Lingulas
showing evidence, to a certain degree at least, of such internal ridges and cal-
losities. In regard to these shell-ridges, King has said : " The muscles, including
the parietals, produce scars, often well seen in the valves of recent Lingulas.
The scars are occasionally liable to become raised at their margin, giving them
the appearance of individualized muscular fulcra or myophores. A specimen
before us has the scar of one of the post-lateral parietals with its inner
margin completely raised in the form of a plate. Such cases are evidently
of abnormal formation ; but they explain the origin of what may be assumed
as normal cases — for example, Lingula albida, in which there are two of the
same kind of plates."*

* On Some Characters of Ling-iila anatina. p. 8.

.,1'

14 PAL.^ONTOLOGY Of NEW YORK.

On the basis of the above nientionod peculiarity,
Mr. Hall has separated siicli forms asL. albida from the
jreiuis LiNCCLA, uiuler the !,reneric term Glottidia * i. e.,
shells in which the pedicle-valve bears two diverging
parietal ridges and tiie Ijrachial valve a median ridge
of about the same length. Representatives of Mr.
Ball's genus have been regarded as confined to liv-
in"- species,! and as representing the genus Lingula in "'"''''^igs. m. n

" _ GtoWidia Paimm, after DAVIDSON.

American seas. rig. lo. PecUcievaive.

Fis. 1 1 . Brachial vahe.

The name Dignomia was proposed in 1871 for certain Devonian and Silurian
species, which are characterized by a strong longitudinal septum in "one or
both valves."!

Type, Lingula alveata, Hall, of the Hamilton shales.

In this species, the median septum is sometimes strong and sharp, sometimes
broad and low, with raised margins precisely as in the pedicle-valve of L.
anatina (see figures of the species, Plate I). In addition, however, to the
median septum, L. alveata, the type species, shows distinct evidence of diverg-
ing parietal ridges, and, moreover, is the only American fossil species that is
known to retain these as a persistent feature. The presence of the longitudinal
septum alone in some degree of development, is by no means a rare
feature among the palaeozoic species, and, as before observed, specimens fre-
quently give evidence of the fact that this has been partially or wholly formed
by progressive accretions to the anterior or median muscular fulcra. (See
fiu-ther on this point the observations on the formation of the platform in the
Trimerellids.) Thus it has attained different degrees of development in
L. (juadrata of the Trenton, L. lowensis of the Galena limestone, L.

* American Journal of Conchologr.V, vol. vi, p. 157, pi. viii, figs. 1-6. 1870.

t Mr. Mavidsojj calKs attention to the close similarity apimrent in GlvUidia Palmeri, Dall, ami Lingula?
Lesiteiiri, Rori.ault, in respect to these septal ridges. (Brachiopodaof the Biidleig-h-Salterton Pebble-bed, p.
3t!2.) We have just refeiTcd to Prof. King's suggestion that the latter species should be placed in a
distinct genus, on account of its strong deltidial callosities, ajiparently adapted for the articidation of the
valves, and it will piobably prove a representative of the genus Barroiseli-a (q. v.).

; Hall, On .some Inipei'fectly known Fonns among the Brachiopoda. 1871.

BRACHIOPODA. 15

Proderi of the Hudson group, L. cuneata of the Medina sandstone, L. centri-
lineata of the Lower Helderberg, L. punctata, L. Delia and L. densa of the
Hamilton, etc. While in many cases it has not been observed and in other
species is known not to exist, it must be borne in mind that all specimens of L.
anatina do not show the internal ridges witli equal distinctness, and that not
infrequently they are all obsolescent. It will therefore be a matter of much
difficulty, if it be possible, to fix upon features of permanent taxonomic value
in the development of these septal ridges.

In DiGNOMiA (L. alveata) it is an important fact that both median and lateral
ridges appear to be nearly equally developed in both valves, and herein
lies a distinctive diiference between this form of development and that charac-
terizing either Lingula anatina or Glottidia. It would not be prudent to attempt
a further sub-division of Lingula on septal features alone, although one cannot
but recognize the great differences of development in these respects. Dignomia,
however, may be tentatively accorded a sub-generic value until its further rela-
tion to, or divergence from Lingula can be demonstrated.

In 1848, Phillips proposed to place such forms of Lingula as L. attenuata,
Sowerby, and L. crumena, Phillips, in a separate group under the designation
Glossina.* The author seems not to have given a diagnosis of the characters
of the division, l^ut evidently intended to include in it a pretty well defined
group of forms. Our knowledge of the internal characters of these earlier
acuminate forms is very imperfect, as they have rarel}- given anv indication of
muscular impressions or septal markings, and it may eventually be advisable
to separate this group from typical Lingulas, under the name proposed by Phil-
lips. We must not overlook the fact that L. cuneata has shown muscular scars
having the general character of those in L. anatina, but this species deviates slightly
in the sub-quadrate tendency of its outline from the group of sub-trigonal forms
constituting Glossina. Mr. Davidson has also shown that similar scars exist in
L. Hawkii, Rouault, a species having the broadly spatulate character seen in
L. flabellulaf and L. Scotica.

* Mem. Geol. Sui-v. United Kingdom, vol ii, pt. 1, p. 370.
t For description, see Supplement.

16 PALEONTOLOGY OF NEW YORK.

We are not awari' that any author lias described or represented the form
and size of the egs of the recent Lingula since the publication of Profes-
sor Owen's observations " On the Anatomy of Terebratula," in Davidson's
'•Introduction to the British Fossil Brachiopoda," 1853. On plate i of this
work, figures l,a,b, c, cl and e, are given representations of the ova after
impregnation has been effected, which indicate that, their form in this condition
is elongate-ovoid or sub-trihedral (7 c). According to Lacaze-Duthiers, the egg
of TiiEciDiuM, in its earliest observed condition, is somewhat pyriform * Morse
describes the eggs of Terebratulina as " generally kidney-shaped, though very
irregular as to form and si/,e."t As to the actual size of the ova discussed by
these authors, Owen's figures, enlarged one hundred and twenty diameters,
would indicate a length of .U mm. Mokse has given no exact measurements
of these bodies ; the youngest endjryo in which the shell is developed, is about .3
mm. in length, and it is fair to assume that the ova are considerably smaller.
On removing the shell from a specimen of Lingula lamellata, Hall, from the Niag-
ara limestone at Hamilton, Ontario, in order to determine the character of the
muscular scars, the interior filling, a compact, fine-grained calcareous mud, was
found to be filled with minute ovoid bodies. The valves of the shell were in
the normal apposition an<l in contact about the entire periphery. The bodies
referred to {ova, as we believe them to be), vary somewhat in size and shape,
their length being from .3 to .5 mm., their form elongate-ovoid or ellipsoidal.
They are closely crowded together, but seldom in actual contact, the interspaces
being filled, not with the mud of the sediment, but with a translucent crystalline
calcite. They arc most abundant wherever the pallial sinuses have extended,
but in the marginal regions have been crowded inward by the intrusion of the
sediment. A section of the interior of the filling shows that these bodies
had evidently been set free into the perivisceral cavity, and have also found
their way into the visceral region after the decomposition of the softer parts
of the animal. That they are not of oolitic or foraminiferal nature is demon-

* Anmile.s ties Sciences Natiirdles, 4th Ser., vol. xv, j>. 802. 1861.

t On lh<' Early Stages <if Teiehratiiliua Septentrionalis ; Memoirs uf the Bo.'^ton Socnety of Natural
Historj'. vol. ii, pnjfe 31, pi. i, tig-. I. See, also, Embryology of Ternbratuliiia, op. idt., pp. 2!)1, 252, pi. viii,
figs. 1-."|.

BRACHIOPODA. 1 7

strated by a thin traiisver.se section, whicli shows them to be simply opaque
masses without evidence of structure save a thin transparent external cover-
ing. Enlarged figures of this internal cast and of the ovoid bodies are given
upon Plate IV k.

On account of the extreme tenuity of the shell in the fossil Lingulas, it is

difficult to ascertain its structure from .sections. The ^^^^ T'^'ri' a,

shell-substance is essentially corneous, and the mineral ^ jp— ^

intermixture is calcic phosphate with traces of calcic
and magnesic carbonates. ^

The organic and inorganic constituents are arranged " 4

in alternating lamellse, the former, according to Gr.a- -— ^^^^

TIOLET,* having a fibrous structure, and the latter being
traversed by numerous microscopic canals. A finely '

preserved specimen of an undetermined species from
the Waverly sandstone at Pierrepont, Ohio, shows vn^.ii. M.ij:iuiiea sccuon of

the lliickest )ioi'tion of the

stronf punctiB, visible to the naked eye on the internal sheii or /.ih^kIh «»««)!« dvom

^ ^ " Davidson, aflertiKATioLET).

surface, where, according to the author above cited, the ^, .■..incous laycs.

7>. niiner.Hl layers with vcr-

calcareous layers of the test are thickest. The same ticaic-iiuiu.

character is also seen in the specimen figured on Plate IV k (fig. 19), an un-
determined species from the Black shale of MadLson county, Kentucky. The
laminae of the shell have exfoliated, exposing the internal cast, which is covered
with minute papillae, apparently the fillings of the inner openings of these
tubes. It would, therefore, seem that these vertical cumals have sometimes
attained a greater development in the extinct than in the living species.

The surface ornamentation is subject to but little variation, usually con-
sisting of concentric lines marking the successive stages in the growth of
the shell. From the paucity of external characters, arises much of the diffi-
culty attending the determination of species, similar in their general aspects.
Still, a few species, exceptions to the rule, have a striking shell-orna-
mentation. In L. punctata, of the Hamilton group, the fine surface lines are

* Jouniiil (le Ccmchyliologie, 2d ser., vol. viii, p. 59. 1860.

18 PALEONTOLOGY OF NEW YORK.

wrinkled into a sort of herring-bone pattern ; L. distinda and L. epimia, Bar-
rande, L. granulata, Phillips, and L. tmuigranulata, McCoy, also have very
characteristic surface markings, consisting of granulations or tubercles with vari-
ous arrangements. In the L. lamellata, Hall,* from the Clinton group of central
New York, and the commingled Clinton and Niagara fauna at Hamilton, On-
tario, the surface is covered by broad, transverse, imbricating, gently undulating
lines, which do not correspond with the curvature of the anterior margin, but
end quite abruptly on the lateral margins. Near the umbo these lines are
crossed by the concentric growth-lines of the shell. Of precisely the same
character is the ornamentation iu L. zebra, Barrande, from the Bohemian
Etage E,t and closely similar to it is that of L. spathata, 'Hall, of the Lower
Helderberg.

The genus Lingula reached its culmination of development in the faunas of
the Silurian and Devonian. In the Palseozoic of North America alone, about
one hundred and twenty species (making allowance for synonyms and the
necessary elimination of heterogeneous forms) are now recognized. Of these
about seventy are from the Silurian. It is not probable that as many more
species are known from the same formations in other countries.

Genus LINGULOPS, Hall. 1871.

PLATE II, FIGS. 24-29; AND PLATE IV K, FIGS. U, 15.

1S71. Lingiilops, H.\i,L. Notes on some Now oi' Iinpeifectly known Forms among' the Brachiopoda,
etc. (March). In advance of Twcnty-thii'il Kept. N. Y. State Cab. Nat. Hist.

1872. Linffithtps. Hall. Idem. (March). Reprinted with Explanations of Figure.?.

1873. IAngu.lop.1, TiAi.r,. Idem. Twenty-third Rept. N. Y. State Cab. Nat. Hist., p. 24i).
1S74. Lingidups, Davidson and KiNc. Quart. .Journ. GeoL Soc, vol. xxx, p. lt)4.

187."). Lingula, U. P. .Jamks. Cincimiati Quart, .lourn. Sci., vol. ii.

Of this remarkable and interesting genus but three representatives are
known. Two of these are from faunas probably equivalent, but from widely
distant localities; Lingulops Whiifieldi, the type-species, from a chocolate-brown

* This name has been applied to two distinct sjiecies, one from the Clinton gioup (Pal. N. Y., vol. ii,
p. 55, 1)1. XX, figs. 4 a, b, c), the other from the Niagara shales at Lockport and elsewhei'e (Geo!. Rept. Fourth
Dist. N. y., 1843, p. 109, fig. 2; Pal. N. Y., vol. ii, IS47, p. 249, pi. liii, figs. 1 and 2). The lattei- has
I)rii>i-ity, and the formei', that above mentioned, may leceive the designation, LinytUa tccniola.

tSyst.Sil., vol. V, 1)1. 10.-), fig.^v.

BRACHIOPODA. 19

or reddish sandy shale Ibund on the Maquoketa creek, twelve miles north-
west of Dubuque, Iowa, and the Lingula Norwoodi, of the late U. P. James,
from southern Ohio and northern Kentucky ; both being from rocks now
referred to the age of the Hudson group. The third species is one here
described* from the Niagara limestone at Hamilton, Ontario, L. Granti. All the
shells are of small size, rarely exceeding 6 nun. in length, and all have
essentially the same external aspect, but the internal casts, often retaining the
character of the muscular markings in exquisite detail, show important
pecuHarities for each species. Of the original species, L. Whitfieldi, very few
specimens have been obtained. In the first notice of the genusf the diagnosis
given was \Qvy brief, and in the following terms :

" The ventral (?) valve presents a small area with a narrow pedicel groove,
and a large lobed muscular impression, which in the cast extends as a narrow
groove towards the base of the shell. The character of the area and foramen
differ from the typical forms of Lingulella, though in that genus the form and
character of the muscular impression has not been determined, so far as I am
aware. For this shell I propose the name Lingulops."i [PI. xiii, fig. 2.]

Shortly after the first publication of this notice, in March, 1871, gutta-percha
impressions, taken from the single internal cast oi'L.Whiifieldi, which had served
the purpose of the original illustration of the genus, were sent by his request, to
Mr. Davidson, and upon these was based the analysis of Lingulops given by
Davidson and King, in the appendix to their jjaper on the Trimerellid£e.§ The
minuteness of these fossils requires the greatest care in the determination of
their internal markings, and the diversity of opinion which has alread}^ been
expressed, both in words and illustration, in regard to these features in the
type-species, must be, to an important degree, due to the personal equation in
observation. Upon plate xix, accompanying the paper of Messrs. Davidson
and King, ;i lithographic figure (fig. 9fl) is given of the single interior then
known, agreeing, except in some minor details, with the original illustra-

* See Supplement.

t Imperfectly known Forms among the Brachiopoda, etc. 1871.
J " Pi-inted L'lgulops by mistake in some copies of the paper."
§ Quart. Journ. Geol. Soc, vol. xxx, p. 1G4. 1874.

20 PALAEONTOLOGY OF NEW YORK.

tion* But iieithtM- of these figures j^roved satisfactory to the authors, and they
inserted an additional figure in the text (p. 1()5). The figure which is now
given of this valve (Plate II, fig. 28) has been made with great care
from the original specimen, and is reduced from a camera drawing.
Though it differs in some respects from previous figures, the accuracy of
its details is supported by internal casts of other specimens of the same valve,
though none are so clearly developed as in the original specimen. Notwith-
standing the great value of the observations l)y the PJnglish authors upon the
structure and generic relations of this species, it must be said, that, of all the
illustrations which have been given of the original valve, the wood-cut referred
to, represents the interior features with the least accuracy.

Both valves of Lingulops have a relatively broad cardinal area, which is
divided transversely into two parts, (a) a smooth, narrow, apical portion ; (6) a
broad inner band, along which the valves appear to have been in contact. In
L. Whilfieldi, this band is flattened and projects into the interior cavity of the
shell, like a narrow lunate shelf; on the pedicle-valve it is concentrically
striated, while, in L. Norwoodi and L. Granti, it is smooth, and not fiat but
gently convex. The pedicle-groove crosses this inner area only, not encroach-
ing on the apical area of either valve ; in the pedicle-valve of L. Whitfieldi it is
sharp and narrow, in the brachial valve, broad and faint; while in the pedicle-
valve of L. iVorwooc/?, it is very indistinct, and not discernible in the opposite
valve.

Directly in front of the cardinal area, is a narrow crescentic ridge, the ante-
rior margin of wlii(;h is deeply excavated. This ridge, which is parallel and
co-extensive witli the cardinal area, bears a median angulation, projecting
backward toward the pedicle-groove. This feature is more clearly defined in
L. Whilfieldi than in any specimens of L. Norwoodi that we have examined, but
it is evident in the pedicle-valve of this species also, where it is interrupted
beneath the beak by a thickened area which may represent the position of the

* The oi-i^nal fig-ure was drawn from a natural cast to which a i>oi-tion of the shell adhered. Davidson
and Kino's figure, binnj,' made from a guttM-pcri'lui iinprrssion, n-ave Uie interior niarkin<rs in their natural
relief.

BRACK 10 POD A. 21

umbonal muscle. No Lingula possesses this peculiar cresentic ridge, but it is a
feature strongly developed and of great importance in the various genera con-
stituting the Family TniMKitEi.i.n>.K, of Davidson and King, and in this respect,
as well as in others to be directly noticed, Lingulops is a Trimerellid.

In the arrangement of the internal impressions on the pedicle-valve, within
the crescent, there is a general similarity to Lingula. An elongate median
impression, evidently the progressive scar of the muscles homologous with the
middle laterals of Lingula, is accompanied, oxi either side, by scars of the central
muscles, and outside of these lie faint scars (niucli better defined in L. Nor-
woodi than in L Whitfieldi), which may be ascribed to the outside laterals.*

These median scars have a sharply elevated anterior edge, but otherwise
their surface is depressed in the older species, L. Whitfieldi and L. Norwoodi,
while, inL. Granti, the muscular area is thickened over its entire surface, form-
ing an incipient platform. From the anterior edge of this area, extends a
median septum, sometimes of considerable length. This, in L. Whitfieldi, is
accompanied, on either side, by a deep groove, outside of which lies a broad
and low rounded ridge.

In Lingula, the median septum does not attain such a development in the pedicle-
valve, except in forms referable to Dignomia, where it extends forward from
the posterior extremity without interruption. In the brachial valvef of Lingula,

*Iii legaid to ihe nomenclature of the muscular anil other impressions in the j)latfurm-l)eaiin{f iiiai'lic-
ulates, it seems best to adopt that proposed l)y the English authors, though it is jiiirely arbitrary and con-
veys no correct impression of the function.al relation of these parts to those of LiNtiL'LA. In the pedicle-valve
of Trimerella, the (interior and media?!, scai-s coi-respond in po.sition to the middles (k) of LiXdrtA ; the laterals
to the centrals (//), and outsiders, ov crternals (?) ; the terminal scars of the crescent to the anteriors (J) and
transmfdians (i) ; in the Lrachial-valve, the anteriors and medians, to the anterior.i (j ) ; the laterals to the
centrals (A), and the crescent scars to the middles (k) and transmedians (i). Lixgtlop.s shows a very clearly
defined transition stage between these genera in muscular chai-acters, and though it has been inipo.<sible to
demonstrate, from observation, the existence of the transmedian muscles in the Trimerelloids, as no speci-
men has been seen which indicates that the lateral scars of the crescent are unsymmetrical, the same fact is
true of fossil Lingulas generally, and in default of other evidence, we :ire left to infer that the nniscular
functions in all these forms were essentially similar.

t Messrs. Daviosox and Ki.vii were strongly convinced that the original specimen of L. Whitfieldi
should be regarded as the brachial rather than the pedicle-valve. Their opinions, which are entitled to the
most respectful consideration, are essentially these : The slit upon the cardinal area, which we have termed
the pedicle-gi-oove, was vei'y faintly defined in the imjn-essions at their disposal, and they regarded it as a
depre.ssion, " nothing more than such as occasionally occui's in the brachial valve of Lingula anatina " (p.
168). Furthermore: "In the pedicle- valve of Tkimereli.a the crown of the crescent has a foriwrd curve

22 PALAEONTOLOGY OF NEW YORK.

however, there is a distinct development of the septum in this anterior portion
of the shell, such as is also to be found in both valves of some Trimerellas.

The posterior outline of the muscular region in the pedicle-valve is very
striking. It consists of a central lobe or scallop, at each side of which is a
somewhat broader lobe, continuous with the faintly defined lateral muscular
scar. It seems evident that this lobed impression, which has been aptly
compared, by Davidson and King, to a Moorish arch, is of muscular origin
and made by separate muscular bands. This appears from the fact that we
shall have to consider the crescent as the base of attachment of the parietal
walls. There is nothing, however, in Lingula or in the Trimerellids from
which an homology can here be satisfactorily elicited. While we should be in-
clined to regard the impression as entirely a nuiscular scar, we may quote the
remarks of the authors above referred to:

" The middle sinus, we have little doubt, has been produced by the umbonal
muscle pressing against the post-parietal or posterior wall of the splanchnoctiele.
It may be suggested that the lateral sinuses have been formed in the same way
by other muscles, but as Lingdla is not characterized by any similarly situated
(at least in the brachial valve*), we prefer the idea that they represent certain
viscera; and they may be recesses produced by the pressure of the ovarian
lobes against the inner side of the post-lateral walls of the splanchnocoele "
(pp. 166, 167).

The validity of this speculation apparently rests, to a great degree, upon the
conception of the authors, that the valve under consideration is not the pedicle-

in the middle, due. we believe, as in Linoula, to tliis poi-tion having been forced out by the pedicle; while
the crescent in the brachial valve has a pointed crown directed backward ; now it is this peculiarity that
plainly presents itself in Lingulops." Again: " In the Ti'ininrellids, as in Lingula, the pedicle-valve has
a short, rudimentary meilian plate, whereas in their brachial valves this part is well developed and elongated,
as it evidently is in Linuulops." Considerable importance is given by the authors to the discussion of the
character and function of what they have termed the "semicircular zone," which we regard as the broad
inner moiety of the cardinal area, moi'O extremely developed in Monomerella and Rhinoeolus. The sugges-
tion is made that it is homologous with that area in the bracliial valve iil' Lingula occupied liy the setal band.
We have preferred to consider the original valve as the ventral oi- pedicle-valve, jiartly on account of the
pedicle-groove, which is certainly better defined than it ai)peared to Messrs. Davidson and King, as well as
from incontrovertible evidence derived from the ojniosite valve, which at that time was imknown.

* "In the pedicle-valve of Lingula aiuitina the transmcdian muscles have their attachment similarly
situated. IVere thi: fossil the saine valve, we skvuld have had little hesitation in referring the lateral simises to
the^e mitiicles, notwilhstanding their being single on one side and double on the oVier in Lt.vav/.A."

BRACHIOPODA. 23

valve. Furthermore, these considerations require us to regard the crescent in
LiNGULOPS as not homologous with the same feature in the Trimerellids, a con-
chision which seems unwarranted and apriori improbable. This point is, how-
ever, maintained by the authors, who, regarding the valve as brachial, suggest
that the crescent " was produced by the attachment of the outer muscular cord
and associated vessels" of the setal band (p. 166), a statement in direct con-
travention of that on page 165, viz., "the second" (the "arched fillet" or
crescent) " is evidently the equivalent of the crescent characterizing the
Trimerellids"; and these authors were the first to demonstrate that this
crescent is, essentially, a parietal scar.

The interior of the brachial valve in Lingulops Whitjleldi shows the cardinal area
and pedicle-groove (as already noticed), and the crescentic ridges essentially as on
the opposite valve. The muscular scallops are represented by three depressions,
closer together than in the other valve. The most striking and important
feature, however, is the platform, sharply developed and showing on its surface
faint indications of the median and lateral muscular scars. This organ is even
more strongly developed in L. Norwoodi and L. Granti, but in none of the species
is it continued into a longitudinal septum. The vascular sinuses have been
observed in L. Whitfieldi only, and these appear to be closely similar to those of

LiNGDLA.

With its several linguloid characters well defined, Lingulops presents both
in its platform and crescent, evidence of a close alliance with the Trimerellids.
It is in this genus that appears the first satisfactory evidence of the develop-
ment of the platform. That this tendency should have advanced farther in
the brachial than in the pedicle-valve, is quite in accordance with the relative
degree of development seen in opposite valves of the same species in Monomer-
ELL.\ and DiNOBOLUS. The elevation of the anterior portion of the muscular scars
in the pedicle-valve in the earlier species, L. Whitfieldi and L. Norwoodi, must
be regarded as the inception of this tendency toward the elevation of the entire
area of muscular insertion, which we find effected in the latest known repre-
sentative, L. Granti.

24 PALJEONTOLOGY OF NEW YORK.

The sliell-substance in Lixgulops is exceedingly tenuous and not usually
resolvable into layers. The fossils are generally preserved as thin white films,
through which the thickened muscular area is plainly visible by its deeper
color. Its color alone indicates that its substance is largely if not quite cal-
careous, difl'ering from Lingula in this respect, but agreeing with Lingulasma
and the Trimerellids.

Genus LINGULASMA, Ulrich. 1889.

I'l.ATK II, FIUS. 17-23.

1889. Lingulasvia, UuucH. Aineiican Geologist, vol. iii, No. (i, p. 383, figs. 5o, h, c, d (p. 378).
Compaj-e Lhiffula Canadensis, Billinos, ]S()2. Paleozoic Fossil.s vol. i, p. 114, fig. 9').

Diagnosis. Shell sub-quadrate, linguliform, sub-equivalve ; the brachial
valve considerably the deeper. Beaks apical, cardinal margins gently sloping
to the sides.

Interior of the pedicle-valve with a low concave platform which extends
over one-half the length of the shell, and is not hollowed on its anterior wall.
The pedicle-area has been largely enclosed within the shell, making a distinct
sheath or shelf, beneath which lie the apical portions of the central and lateral
muscular scars. Crescentic scars scarcely defined.

The brachial valve is deep, with a high platform of about the same extent as
that on the other valve, sloping inward near its anterior margin and continued
axially into a strong septum, which reaches nearly to the front of the valve.
Tlie anterior walls of the platform are broadly excavated, and close against the
base of the septum are hollowed out into short conical cavities. The crescent
is strongly developed and sharply pointed backward at its center, Its lateral
curves are broad, reaching to the edge of the platform. Directly in front of
its central angle lies a short, sharp, median ridge, which disappears near the
center of the platform. Lateral and central muscular scars well developed.

Type, Lingulasma Schucherti, Ulrich.

Observations. This remarkable form serves as a most important connecting
link between the paleozoic Lingulas and the Trimerellids, following, in the

HRACUfOPODA. 25

development of its platforms and other interior characters, close npon Lingulops,
the genus which presents the first deviation, in this direction, from Lingui.a.
Externally, neither LiiVGULOPS nor IjIXgllasma may be distinguished from Lix-
GUt.A, but, notwithstanding this exterior linguloid aspect, both exhibit the most
positive alliliations with the genus Tkimerkli.a. Lingulasma is represented b}'
a single species, and b}- the favor of Mr. Charles SrnufHi;RT we have had at
our disposal a number of specimens from the Hudson group at Wilmington and
Savannah, Illinois, including the internal cast which has served Mr. Ulrich the
purposes of generic diagnosis. These specimens preserve both external and in-
ternal features, the cast referred to being in a most favorable condition for study.
In strong contrast to tiie "minuteness of Lingilops is the very considerable
size of Lingulasma, and though this difierence fails to affect the external linguloid
character of the shell, it is to be reganled, in unison with other features, as evi-
dence of progress in the assumption of the characters of the large, thick-shelled
Trimerellids. The specimen figured on Plate II would be unusually large for
a species of Lingula.

Primarily, in reference to the determination of the valves of Lingulasma, we
cannot hesitate to regard as the pedicle-valve that whicli bears the peculiar
pedicle-sheath and faint anterior median septum. The brachial valve is
then characterized by the strongly elevated septum. Such determination
is in harmony with the characters of the respective valves in Trimerella and its
closer allies, the stronger septum always appearing in the brachial valve, but it
fails to agree, in this respect, with Lingulops, where the septate valve bears
accessory evidence of being the pedicle-valve. We are, however, inclined
to regard this septum or low ridge in the pedicle-valve of Lingulops as a rem-
nant of its inheritance from Lingula, rather than a newly assumed Trimerel-
loid character.

A very remarkable feature in Llmjulasma is the enclosed pedicle-sheath.
This takes the form of an arching triangular shelf extending from the
apex for about one-eighth the length of the valve. Its surface features
are precisely those seen in the cardinal area of Trimerella, viz., a broad

26 PALJEONTOLOGY OF NEW YORK.

deltidimn, with diverging deltidial ridges, outside of which are the areal bor-
ders, all marked with successive transverse growth-lines. This sheath appears
to have been entirely enclosed by the shell about the umbo, but just at this
point all the specimens before us are a little broken, and it is difficult to deter-
mine whether or not its apex was extruded for a short distance. The slight
gaping of the valves on the cardinal margin indicates that this was probable.

Beneath the shelf thus formed lie the umbonal portions of the progressive
muscular scars. The central and lateral scars are strongly developed,
passing forward from the pedicle-shelf in three broad ridges, which
terminate at the anterior margin of the platform. The crescentic mus-
cular fulcrum is but faintly visible on this valve, though a broad flabellate
scar, apparent on each side, probably comprises the terminal and posterior
parietal impressions. The platform is comparatively thin and is solid, showing
but slight excavation on its anterior wall. From its center a low median ridge
extends about half-way over the anterior area of the valve ; its margins are
excavated by shallow furrows, which unite at the extremity of the ridge and
extend to the anterior margin of the valve ; on either side of this median fur-
row is a broad, low elevation, the entire arrangement being equivalent to that
seen in the pedicle-valve of Lingvlops Whitfieldi, though the features are not so
conspicuously developed.

In the opposite or l)racliial valve the crescentic ridge is very strongly
developed, its central portion or crown being separate from the lateral
portions. From its posterior angle the sides diverge for a short distance,
ending- abruptly ; and from outside and behind these short arms, the ridge
again appears, being broader and flatter than before, and sweeping in broad
sub-marginal curves to the anterior edge of the platform. The external scars
are more distinctly seen than in the pedicle-valve, but they are not very satis-
factorily defined. From the crown of the crescent, a low axial septum passes
forward to the edge of the platform, dividing the central scar, on either side
of which may be seen the lateral impressions. The platform is moderately
high and its edge is a little incurved between each ante-lateral angle and the
median septum. The latter feature is very strongly developed where it joins

BRACHIOPODA. 27

the platform, reaching a height nearly eqnaling tlie deptli of the valve. TIic
platform itself is solid, except for a sliulit broad concavity on the posterior wall,
which is continued into a minute conical excavation on either side of the base
of the septum. No vascular markings are visible on any of the specimens.

The external surface of the shell in Lingulasma Schucherti is beautifully
sculptured. The concentric growth-lines are very fine, but at intervals bear
bead-like granules, which thus become arranged in rows radiating from
the apex of the valves. Over the cardinal slopes these granules become
transversely elongated and crowded together, usually showing a tendency
to merge into the growth-line on which they lie. We have no personal
acquaintance with any species congeneric with Lingulasma Schucherti, but as
suggested by Mr. Ulkich, the Lingula Canadensis, of Billings,* from an essen-
tially equivalent fauna (Hudson group of Anticosti) as L. Schucherti, may
prove to be a Lingulasma. Upon seeking to obtain specimens of the Anti-
costi species, we have learned from Mr. Whiteaves that Billings' type-speci-
men, and the only one in the possession of tlie Canadian Survey, was lost
many years ago, and all endeavors to secure specimens from other sources have
proved unsuccessful. As far as may be judged from the description and
illustration of external features, given both by Mr. Billings and Mr. Davidson
(the latter author has identified the species in the Llandeilo formation in Ayr-
shire, Scotlandf) the agreement in size, proportions and surface ornamenta-
tion is so close as to suggest almost a specific identity with the Illinois form ;
and, moreover. Billings' figure indicates the presence of a prominent longitudi-
nal septum. Mr. Ulrich directs attention to similar suggestive resemblances
in the species Lingula granulata, Phillips, and L. tenuigranulata , McCoy,:j; the
former from the Llandeilo, the latter from the Bala beds.

The shell substance in Lingulas.ma is calcareous, with a considerable
intermixture of organic matter. Whether these components are arranged
separately in the apparent laminas of the shell, as in Lingula, is not de-

* Paiffiozoic Foss., vol. i, p. 114, tig-. 1)5.

t See Qeol. Mag-,, 1877, p. 16, and Sil. Suppl., p. 202.

X See David.son Silur. Brach.. pi. ii. tigs. IS-IS and U-14.

28

PALAEONTOLOGY OF NEW YORK.

. termined, but we have evidence that the outer or epidermal layer is more
largely corneous than those within, and, so far at least, its structure is in
harmony with tliat of Li.ncula, as demonstrated by Gratiolet. But on the
other hand, the relative amount of mineral matter in the shell is far in excess
of that in Lingula, and its structure in this respect is wholly in consonance with
the other features which establish- its transitional position in the line of de-
velopment from Lingula to Tkimeiiella. In the latter genus and its associates,
the heavy shells have been rarely preserved, or when preserved, their original
structure is so essentially altered by dolomitization and crystallization, that it is
impossible to gain an accurate conception of their composition. Undoubtedly
they were substantially calcareous, with small percentages of organic matter, the
latter perhaps relatively increased in the thinner-shelled forms,like D[N0B0lus and
some species of Monomerella. The evidence at hand would lead to the presump-
tion that the loss of the organic constituents of the shell, and the increase
in calcareous matter, progresaed pari pass2i with the assumption of Trimerelloid
characters.

Genus L A K H M I N A , (Ehlert.* 1887.

1885. Dandsonf.llti,\{ ji.K<iKi!. Mem. Geol. Surv. IniUa ; P.al.'ecMitulogia liidica, Ser.XIlI, I.iv, fast-.O, p. 762.

Not Datndxonella, MrNiKR-CnALMAs, ISSO. Bull. Socieb' Gfologi<iue de France.
1S87. Lakhmina. (Khi.kht. l''i.-<c-hi'i-V Manuel de Cdnchyliologie ; Brachiopcides, p. 12C5.

Tins genus is defined by Dr. Waagen in essentially the following terms:
General outline more or less linguloid.
The ventral valve is tlie larger and
possesses a prominent apex, which is
provided, on its lower surface, with a
deep furrow for the pedicle. In tlie in-
terior of the ventral valve, the cardinal
margin is somewhat thickened, without

„ . ]• • 1, , >>i'ri<J^onena[=Lalhmimi)linriuloUles, a.tlevW\A.GKii.

lorming a distinct area. Below this F"g l^l- I'ediolcvalve. fig. U. Brachial valvc.

^ 111 llie i,iei.aialiuii ul' the discussiuu v( iliis yeiiu-s and g-eiierally tliioiigli,Mit the vnUune, the term
Davidso.nblla had I.een adi.pted, not lieing awaie that the name h.id been u.sed liy Munier-Chalmas in 1880
for a genus of Li.assie brachiopods allied to Thbcidium. We are therefoi-e reluctantly compelled to adopt the
term Lakhmina. proposed by CRhlert ; though it must not be forgotten that it is to Dr. Waagen we are
in<lel)t<'d for the careful analysis of the genus.

BRACHIOPODA. 29

extends a not very large triangular platform, which is vaulted, and supported
by a median partition not extending beyond its anterior margin. This plat-
form is enclosed by low, rounded ridges which originate near the pedicle-furrow ;
its surface is flattened medially', but concave on the sides. Of muscular im-
pressions nothing can be ob.served.* In the dorsal valve the cardinal margin
is but little thickened and slightly curved. In the middle it bears a thickened
process, which is directed somewhat upward and inward, extending jjartly into
the apical cavity of the other valve. From beneath this process, a short thick-
ened platform takes its origin ; it is not even on the upper surface, but to all
appearances spirally rolled ; it is concave in the middle and bears on both sides
elevated crests with sloping lateral faces ; its anterior margin is curved inward,
and the whole platform seems to be excavated below. From its sides diverge
two bifurcating ridges, and a median septum extends nearly to the anterior
margin. Near the lateral margins two sharply defined spaces are enclosed by
narrow ridges. The interiors of both valves are marked with radiating striye.
Shells small ; shell substance very thin.

Type, Lakhmina linguloides, Waagen, op. cit., p. 764, pi. Ixxxv, figs. 3-6.

In the present state of our knowledge., this genus must be regarded as the
earliest representative of the Trimerelloid brachiopods. Its occurrence is in the
so-called " Obolus-beds" of the Salt-Range of India, in association with several
other peculiar inarticulate brachiopodous genera, e. g., Neoboi.us, Discinolepis,
ScHizopnoLis, etc. At the date of the description of these genera (1885),
this formation was considered as conformable with the overlying Carboniferous
and Permian rocks of the " Productus-limestone " series, and was, therefore,
referred to the Carboniferous age. The fauna boars upon its Hxce a primordial
expression, and, before the detailed study of the brachiopods, was regarded by
Mr. Wynne, Dr. Stoliczka and Dr. Waagen himself, as of primordial age.
But the subsequent determination by Mr. K. D. Oldham, of great unconformity

*Dr. Waagen does not consider the lateral impressions seen on his figure (which, he says, represent
these features too sharply) as of muscular origin, but as the deepened spaces outside the crescent. They
certainly are similar in position and extent to the terminal scare as .leveloped in some species of Mono.mer-
ELLA and Tkimekella.

30 PALEONTOLOGY OF NEW YORK.

in the adjacent beds, and the more recent discoveiy by Dr. Warth, of trilobites
in the " Obohis-beds," which have been referred by Waagen to the genera
Conncephalites and Olenusi?), point conclusively to such an age* Never-
theless, some of the brachiopod genera show certain details of structure which
indicate an important progress from the types exemplified in their nearest
primordial allies; for example, the great cardinal process in Neobolus, the
hince-line in Cardinocrania, and thus, also, in Lakhmina, the cardinal process
in the Ijrachial valve is developed to a greater degree than has been observed
among the later Trimerellids. The peculiar modification of the platform in this
valve is also an important character. Tlie advance apparent in the develop-
ment of this feature in tlie l)rachial valve of Lingulops and Lingulasma, over
that of the opposite valve, is here seen in the strongly elevated, though short,
deeply enrolled posterior plate. The single species of this genus is quite small,
and some of its internal characters are not well understood.

The genera Trimerella, Dinobolus, Monomerella, and Rhinobolus, show a
remarkable uniformity in their broadest characters, which may be expressed
by the following analysis of the Family Trimereltad^, Davidson and King :

Shells essentially calcareous, usually thick and heavy. Umbo of the pedicle-
valve generally high, solid or hollow ; when the latter, double or triple-
chambered. Cardinal area well developed ; hinge-line inarticulate or with
rudimentary teeth (?) ; supported in the pedicle-valve by a vertical axial
wall or buttress. Each valve bears, in its post-median portion, a more or
less conspicuously developed platform, which may be solid or hollow ; when
the latter, it is double-chambered ; from its anterior end extends a vertical
septum, which is usually larger in the brachial, tlian in the pedicle-valve. A
narrow crescentic impression lies just witliin the hinge-line, terminating
within the lateral margins in broad muscular scars. The surface of the plat-
form bears three or four pairs of similar scars. The pallial sinuses make a
broad curve over the anterior area of each valve.

This group has been made the subject of an exhaustive analysis by Drs.

* See Note on the Discovery of Trilobites by Dr. H. Wartii, in the Neobolus-beds of the Salt-Rang-e ;
liy the Director, Geological Survey of India: Records Geol. Surv. India, vol. xxii, pt. 3, p. 153. 1889.

BRACHIOPODA.

^ 1

01

Thomas Davidson and William King * and though fifteen years have now
elapsed since the date of its publication, later observations have hitherto added
comparatively very little to the results achieved by these eminent investigators,
and have taken nothing awa}- from their value. The scope of this work in-
cluded not only a detailed discussion of the characters and rehitions of the
family, involving the establishment of an elaborate anatomical nomenclature,
but also descriptions of all the species then known to represent the three genera,
Trimerella, Monomerella and Dinobolus. This nomenclature we have adopted
w^ithout essential modification, and its application is sufficiently exphiined by
the accompanying , .^^^^

outlines, showing , ; / % f

the internal feat- i ^=^$^^Sl]^^^% ' ^ ■'"

ures 01 Irimerella, ^y'^ryt''']'^' ^IW'"

taken from the same ^ f'' ' \aYa\ v\^'^ ^""/t^r • ' W)^ "^'^'^'^"'^

work. We have '-jl v-' '^~'' "^^U 11" '„::."--*-^ ' • ■

also accorded recog- ^""i \ / | ' ^..

nition to the generic
term Rhinobolus,

which was made a fig. is. Pedicle-vnUc of TnmereHa. Fig. 16. lirachial valve of Trimerella.

. f_ After Davidson anO King.

synonym lor i rim- „, rleltiilium. <>, canlinal sockcU.

Ij, (leliidial slope. j. pl.atloini.

WPPTI A in tlintvporV <^. dcltidial ridges. k, platform vaults.

ERELLA in tnai worn, ,, ^,,^.j, ,j,„.,,e?s. (,' median plale.

e, cardinal callosities. *n, median .scars,

but we now possess /■ cardinal facet. ii, anterior scars.

^ fj, lozenge. o, lateral scars.

.1 1 1 • A. cardinal Imttress. p, post median scars.

a COnSlCierablV m- ;. umbonal chambers. 9, crown j

" j. platfiirni. r, side [crescent,

r-rpisprl knnwlodo-p /;. platform vaults. .?, end )

Cre<l»eu l\nu\\lLtli;fc; , median plate. t. transverse scars.

m, median scars. «, archlct (vascular sinuses).

nf tViivf tnrni Mtld ii, anterior scars. v, cardinal scars.

OI Ullb lUllU, cUm o, lateral scars. lo, sub-cardinal scars.

- p, post-median scars.

have elsewhere ?, crowni

r, side j crescent.
, J 1 s, end )

quoted a SUbSe- t. transverse scars.

u, archlec (vascular sinuses).

queutly expressed •:; ^{^;!i^^,^^.

opinion of Mr. Davidson's, abandoning his earlier views on the value of this

* On the TrimerellidiB, a Paleozoic Family of the Palliobranchs or Brachiopotia. By Thomas David-
son, Esq., F. R. S., F. G. S., etc., and Professor William King, Sc. D. Honoris Causa, Queen's University in
Ireland: Quart, Joura. Geol. Soc, vol. xxx. pp. 124-173, pis. xii-xix. 1874.

32 FALJ:oyTOLOGV OF NFlf YORK.

genu.s. Ill an appendix to their paper, tlie authors mentioned discussed the
character of the genus Lingulops, then known only from the interior of a
single valve, and pointed out its affiliations with the Trimerellids. Of this
genus also our knowledge has greatly progressed, and we have now not only an
accurate understanding of the interiors of both valves of the type-species, L.
Whitjkldi, but also of two other species, L. Norwoodi and L. Granti. These
have furnished indisputable evidence of Trimerelloid characters, and show the
first deviation in this direction from the typical Lingula. Added to this is the
genus LiN<;i i.ASMA, recently described by Mr. E. 0. Ulrich, which presents
anotlu-r interesting and important link in the development of this family.
These latter genera (and we have elsewhere adverted to the same subject
more at length) are neither true Trimerellidse under the foregoing definition
of this group, nor can they be properly included under the Lingulidas, except
as a matter of convenience in classification, and we here meet, as we often
do in the study of the inarticulate brachiopods, an emphatic, protest against
the unnatural rigidity of any scheme of classification, requiring the alignment
upon the same plane, of forms which may be, in various directions, successive
and gradational.

The anatomical features of these shells calling for especial attention are (1)
the platform, (2) the umbonal chambers, (.3) the muscular scai's. The first two
are treated in reference to their development and functions in another place
(see page 46). The last is most remarkable for the striking specialization
of the so-called " crescent," a sub-marginal, cardinal impression, skirting the
posterior area of the shell in both valves and terminating in, or just enclosing
at about the middle of the sides, a prominent, sometimes compound scar. This
is believed to be the impression of a strong muscular post-parietal wall, its
position being quite analogous to the same feature in Lingula. The lateral and
terminal impressions arc undoubted analogues of those occupying similar posi-
tions in L. ariaUna {i, /, /, in the pedicle-valve; /, /, k, in the brachial), and
though evidently compound, it has been hitherto impossible to resolve them
into more than two distinct pairs of scars. The median impression, /. e., that
covering tlie surface of the platform, is readily resolvable into central, lateral.

BRACHIOPODA. 33

and, usually, anterior scars ; the post-median impression, indicated upon David-
son and King's figure above given, and considered by these authors as the
marks of the genitalia, is, usually, extremely indistinct. Just within the
cardinal margin are seen, more clearly in RmNOBOLUS than elsewhere, two small,
distinct scars (umbo-laterals), the function and analogues of which are not
understood.

Genus TRIMERELLA, Billings. 1862.

PLATE IV A, FIGS. 1-10; and PLATE IV li, FIGS. 1-6.

1862. Trimerella, Billings. PaljEOzoic Fossils, voL i, p. KiC.

1867. Trimerella, Lindstrom. Ofvers. af KongL Vet«nskaps-.\k:id. FoihaiulL No. 5, p. 253, pL xxi.

1S6S. Trimerella, Lindstrom. Geological Magazine, vol. v, p. 441.

1S70. Gotlandia, Trimerdla, Dall. Ameiican Journal of Conchology, vol. ii, pt. 2, p. 160.

1871. Trimerella, Meek. Amencan Journal of Science, Third Ser., vol. i, p. 30.5.

1871. Trimerella, Dall. American Journal of Concholog-y, vol. vii, pt. ■>, p. 83.

1872. Trimerella, Davidso.v and KiSG. Report Brighton Meeting Brit. Assoc.

1873. Trimerella, Hall. Twenty-third Kept. N. Y. State Cab. Nat. Hist., pi. xiii, figs. 11-16.

1873. Trimerella, Mekk. Geology of Ohio; Paleontology, vol. i, p|> 182, 183, pi. xvi.

1874. Tnmerella, Davidsox and King. Quart. Journ. Geol. Soc, vol. xxx, p. 143, et seq.

1875. Trimerella, Niohol.son. Rejit. PaliBOnt. Piov. Ontario, pp. 67, 68, figs. 36, 37.

Diagnosis. Shell thick ; outline elongate-ovate.

Pedicle-valve with an erect and straight umbo, which is usually solid for the
greater part of its length, but double-chambered toward its base ; cardinal area
very prominent ; deltidium broad ; deltidial ridges more or less conspicuous ;
deltidial callosities slightly developed ; cardinal slope well defined. Crescent
sharply incised over its summit, but faint toward the sides, where it is con-
nected with the broad lateral and terminal scars which are not so distinctly
outlined as in the allied genera. Platform long, narrow, and strongly devel-
oped ; platform-vaults tubular, the dividing wall being continued as a short
septum in front of the platform. Muscular scars of the platform usually ex-
tremely faint, but under favorable preservation divisible into median and lateral
components. Pallial sinuses faint.

Brachial valve with a marginal umbo, which is much thickened in some
instances, without producing a cardinal area, though making a prominent
apophysis which is extended against the cardinal slope of the opposite valve.

34 PALAEONTOLOGY OF NEW YORK.

Crescent as in the otlier valve. Platform higher than in the pedicle-valve,
its vaults extending scarcely so far backward. Anterior median septum long,
often reaching almost to the margin. Muscular and pallial impressions faint.
Type, Trimerella gi'andis, Billings.

Observations. The species of this genus are subject to some interesting varia-
tions, though, in the development of certain features within the limitations of
a given species, such great differences are not as noticeable here as in Monom-
ERELLA and DiNOBOLUs. The relative size of the great cardinal area appears to be
a permanent character. A tendency toward the subdivision of the umbonal
cavity by a vertical septum (cardinal buttress) is apparent in all species, and
constitutes an approach to the large umbonal chambers in Monomerella. The
great development of the platforms necessitates the abbreviation of the umbonal
chambers, while, accompanying the obsolescence of the platforms in Monomer-
ella, is a resultant increase in the size of these chambers.* In the brachial
valve the umbo is incurved, and just beneath, or within it, is sometimes devel-
oped a strong process, grooved on its outer surface. This feature is seen in T.
Ohioensis, Meek and T. Lindstrami, Dall. Messrs. Lindstrom, Davidson and
King, and Dall have been disposed to regard this as a cardinal process, fitted
like a tooth into an excavation at the base ol' the deltidium of the opposite
valve. The evidence of such a process affording attachment for muscles open-
ing the valves is generally wanting among the other genera, and other species
of this genus; and if this process served such a function, we should expect to
find correspondingly large and deep muscular scars upon the platform of the
pedicle-valve. Our evidence on this point is rather negative, though through-

* The Gotland .«iM!cies, T. Lindstrcemi, D:i\\. i>ossess(!a a peculiar umbonal character. The small lateral
umbonal chambers are forced wide ajiart by the development of a median, undivided cavity, which makes
the umbo hollow for its entire length. This cavity i.s represented in the figfures given by Lindstrom, David-
son and King, as oijening- at the hinge-line or posterior margin of the platform. No similar structure, or
any tendency to its formation, has been observed in any other species ; on the contrary, the strong cardinal
buttress usually occupies this median position. Several specimens of the pedicle-valve of this species, after
having the matrix carefully removed by means of caustic potash, give no evidence whatever of this
oiiening, the shell being i-erfectly continuous from the platfcn-m to the deltidium, and we are led to suggest
that the external opening of this cavity, so out of harmony with the typical characters of the genus, may
be line to fortuitous causes. The cardinal buttress, however, is replaced by a remarkably bioad and <ieep
excavation.

BRACHIOPODA. 35

out the Trimerellas, the scars are much less sharply defined than in the other
genera of the family. Thus, there may be no sufficient reason to doubt that
when this apophysis is developed, it is analogous to the cardinal process in the
articulates; and we have confirmatory evidence ol' this function of the process
in its great development in Lakhmina.

The platforms in tlie Trimerellas have usually about the same relative degree
of development, being generally slightly larger in the brachial tlian in the
pedicle-valve, and vaulted for almost if not quite their entire length, except in
the species T. Billingsi, Dall, where they are solid for about two-thirds their
length. This species again indicates the tendency toward Monomerella in the
gradual obliteration of these platform-vaults. The usual faintness of all the
muscular impressions must be due, in an important degree, to the condition of
preservation of the fossils. The shells were ainong the most ponderous of all
brachiopods, and the muscles to wield them must liave been of great size and have
produced strong scars. The American specimens of Trimereli.a are almost
invariably internal casts in dolomitic limestones, and the removal of the shell-
substance left great space for the operation of crystallizing forces which would
go far toward the obliteration of these impressions. An interesting feature is
the not infrequent irregular development in the vaults of the platform, one
being sometimes shorter or broader than the other. A tendency to lateral
asymmetry in the growth of the umbonal portions of the shell is sometimes
seen, resulting in a deflection of the beak and platform to one side. (See
Plate IV a, fig, 3.)

In some species, noticeably in T. acuminata, Billings, the platform of the
pedicle-valve bears a deep median furrow, beginning at the base of the cardmal
buttress and narrowing anteriorly. This feature is developed, to a greater or
less degree, in most of the species, and may represent the position of the ovar-
ies (post-median scar, Davidson and King).

Trimerella is represented in American faunas by five species : T. grandis and
T. acuminata, Billings : T. Billingsi, Dall ; T. Dalli., Davidson and King ; T.
Ohioensis, Meek. All these are known to occur in the Guelph limestone of the

36 PALJ^OKTOLOGY OF NEW YORK.

Province of Ontario; T. Ohionisis, T. grandis and T. acuminata are known in
the Niagara dolomites of Ohio, and T. acmdnata from Port Byron, Illinois, but,
strangely enough, we have no knowledge of the occurrence of any species of the
"■enus in association with the great numbers of Monomerella and Dinocolus
in the rocks of the same age in Wisconsin ; T. acuminata has been found by
LiNDSTROM in association with T. Lindstmmi, on the islands of Gotland and
Faro ; T. Wisbi/msis, Davidson and King, is a little known species from the
former island. The age of the Swedish specimens is that of the Aymestry and
Wenlock limestone of Great Britain.

Genus DINOBOLUS, Hall. 1871.

PLATE IV B, FIGS. 13--24.

ISoO. Lingula, Rouali.t. BiilL Soc. GdoL de France, 2ii(i sei-., voL vii, p. 128.

1853. Obolii.1, Davidson. Introduclion to British Fossil Bracliioiio<].-i, p. !SS.

185S. Ohohui, BiLLi.NGS. Kept. Geological Survey Canada, p. 189.

1859. Obohis, Salter. Murchison's Siluria, Second Ed., p. 54S.

1800. Obobis, LiNDSTROM. Ofvei-s. af Kong. Vetenskaps-Akad. Forhaudl., p. 37;').

1862. (Uonradia). Hall, MS. See Davidson, Quart. .lourn. Geol. Soc, vol. xxx, p. 159, foot note. 1874.

1863. Lingula, Saltbh. Quarterly Journal Geolo<fical Society, vol. xx, p. '294, pi. xvii, tigs. 2, 3, 6.
1866. Lingida, David-son. British Silurian Brachiopoda, p. 41, pi. i, figs. 21-26.

1866. Obolim, Davidsox. British Silurian Brachiopoda, p. 59.

1868. Obolus, Hall. Twentieth Kept. N. Y. State Cab. Nat. Hist., p. 368, and 1870, idejn., Revised

Edition, p. 37.5.
1868. Obohis [TrimercUaf], Meek aud W'orthb.v. Geol. Survey Illinois, vol. iii, p. 351, pi. v, fig-. 7.
186'J. Lingula, Davidson. Quarterly Journal Geological Society, vol. xxvi, pi. iv, tig. 3,
1871. DiTUibohus, Hall. Notes on some New or Imperfectly known Forms among the Brachiopoda, p.

4, March ; in advance of Twenty-tliird Rept. N. Y. State Cab. Nat. Hist.

1873.

1871. ObnlelUna {■partim). 'Bihunos. Canadian Naturalist, p. 222. December.

1S71. Trlmerella {pnrtim). Dall. American Journal of Couchology, vol. vii, lit. 2, p. 83.

1872. ObolelVma {partim), Billinus. Cauad. Nat., p. 330, Dec. : Amer. Journ. Sci., vol. iii, p. 359.
1872. {Conradia). Hall. American Journal of Science, Third Sei-., vol. iv, p. 107 ; and, 1873, Twenty-
third Rept. N. Y. State Cab. Nat. Hist., p. 2.50.

1872. Diin>boliis, David-SON and King. Rept. Brighton Meeting Brit. Association.

1872. Z>iwo6oZ!W," Davidson and KiN(i. Geol. Magazine, vol. ix ; and Ann. and Mag. Nat. Hist., vol. x.

1874. THmbolm, Davidson and Kino. Quart. Journ. Geological Society, vol. xxx, p. 159.

1875. Dimbolus, Hall aud Whitfikld. Geol. Surv. Ohio ; Palieout., vol. ii, p. 130, pL vii, figs. 3, 4.
1875. Dlnobohu!, Nicholson. Pal.Tontology Province of Ontario, p. 18, fig. 6a; p. 68, fig. 38.

1870. Trematis, Barrande. Systiime Silur. Bohfime, pi. 94, tig. vi ; pi. 95, fig. x.

1880. D'nwboliwi. Davidso>j. Geological Magazine, new ser., vol. vii, p. 340, pi. x, tigs. 1-6.

1881. Dinobolus, David.son. Brachiopoda of the Budleigh-Salterton Pebble-bed, p. 365. pi. xl, figs.

22, 23.

1882. Dinoholiis, Wiiitfield. Geology of Wisconsin, vol. iv, p. 347. pi. xxvii, tigs. 8-10.

BRACHIOPODA. 37

Diagnosis. Shell sub-circular ; valves convex, tiiick.

Pedicle-valve Avith an acute and slender beak; cardinal area triangular, more
or less elevated, but never so higli as in Trimekella or Monomekella. Cardinal
margins sometimes of considerable width. Umbo generally solid, but often
slightly excavated on either side of a simple or double vertical wall, or buttress.
Crescent distinct, its apex making a retral angle; narrow over the crown,
widening into the great terminal scars. Platform low, broadly V-shaped on
its anterior margin, which usually lies at about the middle of the valve ;
generall}^ with very short, flattened, abruptly conical vaults, but occasionally
these vaults are of the same relative length as in Trimerella, though much
shallower. Central and lateral muscular scars on the platform usually distinct,
the former lying in a depressed median groove, the latter occupying the greater
portion of the surface. Subcardinal and anterior scars rarely discernible.
Anterior median septum scarcely developed. Pallial sinuses faint.

Brachial valve with the beak submarginal, inconspicuous and usually not
discernible; hinge-area very narrow. Crescent very strong, especially over
the crown, where it makes a sharp posterior angle beneath the beak,
sloping thence very gently, being almost transverse for about the width
of the platform, then bending quite abruptly and being slightly interrupted at
the position of the terminal scars, which are more approximate than in the
opposite valve. In the type-species, the crown of the crescent, as usually
developed, is a sharply incised, narrow furrow, bounded within by a broad ele-
vation sloping to the position of the subcardinal scar, but not infrequently it
is a ridge, bounded in front and behind by a deep furrow. This difference in
appearance is due to the varying development of the anterior furrow, which is
sometimes quite suppressed. Platform narrower and more sharply V-shaped
than in the opposite valve ; vaults usuall}'^ very short and abruptly conical.
Lateral and central scars on the platform conspicuous, the latter lying in a deep
median furrow, at the front end of which are sometimes seen the faint anterior
scars. In the line of this furrow, directly in front of the apex of the crescent,
lies the deep impression of the subcardinal muscle, which makes a prominent
feature on the cast, suggestive of the filling of the umbonal cnvity, which it

38 PALEONTOLOGY OF NEW YORK.

may be to some extent, although the apex of the beak is actually quite remote
from it. From this point to the center of the crescent extends a short furrow,
on either side of which lies the impression of an accessory scar, probably cor-
related to the urabo-lateral scars of Rhinobolus and Trimerella. Pallial sinuses
more or less distinct. Median septum low, but stronger than in the opposite
valve.

Type, Dimholus Conradi, Hall.

Observations. Such considerable variations in certain features occur within
the limitations of a single species of this genus, that we are disposed to regard
the recognition of the eight or nine species, which have been described, of
somewhat questionable authenticity. We have befoi'e us a large number of
finely preserved specimens of the type-species, D. Conradi, from Le Claire, Iowa;
Cedarburg, Wisconsin ; Hawthorne and Port Byron, Illinois ; all of which
indicate that variations are to be expected (1) in the development of the delti-
dium, which though usually quite low, may attain a very considerable eleva-
tion ; (2) in the size of the platform-vaults, which in both valves, are usually
no more than a broad, general excavation of the anterior walls of the platform,
narrowing abruptly into minute conical cavities, though in the pedicle-valve
they occasionally are long and tubular, and, in both valves, there is some-
times evidence of a tendency to form two or even three chambers in each vault ;
this may be regarded as an abnormality, but it occurs in at least six instances
in the examples at hand ; (3) in the position of the platform, its apex usually
lying at about the center of the valve, but sometimes situated more
posteriorly.

Upon comparing the features of the interior of D. Conradi with the best
known of the other species, D. Davidsoni, Salter, we do not observe features
which lead to a satisfactory specific distinction. From the figures given by
Davidson and King,* it appears that this species is also susceptible of varia-
tion, for example, in the development of the median scar in the pedicle-valve,
which may be either a ridge or a furrow. In the description and figures of

Lou. cU., pi. xviii, lags. U-11.

BRACILIOPODA. 31)

Dinobolus Sclmidti, Davidson ;iiul King, from Esthonia, Russia, as given hy these
authors, it is inii30ssil)le to cite specific dillerences from D. Coaradi ; D. Cana-
densis, and D. magnijicus, Billings, are known only irom their exterior; I).
Woodwardi, Salter, is imperfectly understood, while D. tramversus. Suiter, D.
parvus, Whitfield, and D. Bohemicus, Barrande, appear to be well defined
species.

The close relationship of Dinobolus to Monomerella is apparent both in the
slight development of the umbonal cavities in the pedicle-valve, and in the gen-
eral aspect of the interior of the brachial valve, the shape of its platform and
development of its muscular scars. The difierences, however, are of perma-
nent value. No true platform-vaults are formed in either valve of Monomer-
ella, merely a broad, general excavation of the anterior walls of the platform;
moreover, the crescent in this genus never attains the strong and peculiar
development seen in Dinobolus, but is more of the nature of that in Trimerella.
The approach to Trimerella indicated by the long vaults occasionally seen
in Dinobolus, has been referred to, but in no instance among the Trimerellas
or Monomerellas has there been observed any tendency to a duplication of
these vaults, as in Dinobolus. In some respects, therefore, Dinobolus stands
as the connecting link of these two genera ; or, as it was the first of the
genera to appear in pakeozoic faunas, it may be naturally considered the
more comprehensive type of Trimerella, Monomerella and Rhinobolus, from
which these latter may have derived many features by easy stages of evolu-
tion.

Dinobolus makes its first appearance in the Lower Silurian,* D. Brimonti,
Rouault,t being from the Budleigh-Salterton pebbles, and various localities in
Brittany, of the age of the lower Llandeilo, or the Gres Armoricain ; D.
magnijicus, Billings, and D. Canadensis, Billings, from the Black River limestone

* Mr. Davidson describetl a species, Dinobolus* Hieksi, from the Upper Aieni'f of St. Drivals (^uurt.
Journ. Geol. Soc, vol. xxxi, p. ISS, pL x, fig-, (i. IST.t; and British Silurian Brach. Suppl., p. 212. pi. xvi,
tig-. 19. 1SS8), but the char.u-ter.s ol' the single specimen are so obscure as to render this refei-ence exceed-
ingly <piestionable.

t Davidson. Brachiopoda of the Budleigh-Salterton Pebble-bed, p. 305, figs. 1, 2 (p. 306), pi. xl. figs.
22. 23. 1881 .

40 PALEONTOLOGY OF NEW YORK.

(Trenton); D. parvus, Whitfield, from the Galena limestone (Trenton) at
Whitewater, Wisconsin; D. Schmidti, Davidson and King, is stated to be from
the Lyckholmer Schichten of Esthonia, Russia, considered to be nearly the
equivalent of the Caradoc and Trenton ; the greatest individual development
of the genus, however, is in the Niagara fauna and its equivalents, D. Conradi
being the American representative of D. Davidsoni, Salter, a Wenlock species
occurring near Dudley and elsewhere in England, county Kerry, Ireland, and
on the Island of Gotland ; D. transversus and D. Woodwardi, Salter, are from
the same horizon, and the Trematis Bohemica, Barrande (= Dinoholus), is from
an equivalent fauna (Etage E-e.,).

Genus MONOMERELLA, Billings. 1871.

PLATE IV c, FIGS. 1-18; and PLATE IV D, FIGS. 1-15.

1871. Monomerella, Biu.ings. Canadian Naturalist, vol. vi, p. 220.

1872. Mwimnerella, Davidson and King. Ann. and Mag-. Nat. Hist. ; GeoL Mag. ; Report Brighton

Meeting of British Association.

1874. Monomerella, DAvrnsoN and King. Quarterly Journal Geological Society, vol. xxx. p. 155.

1875. Monomerella, Nicholson. Rept. PaljBontology of the Pi'ovince of Ontario, p. C8.

1875. Monoinerella, Hall and Whitfield. Geol. Surv. Ohio ; Palaeont., vol. ii, p. 131, pi. vii, figs. 1, 2.
1884. Monomerella, Whitbaves. Palaeozoic Fossils, vol. iii, pi. 1, pp. 5, 6.

Diagnosis. Shell usually thick, but in some cases quite thin ; outline vary-
ing from elongate-ovate to subcircular. Surfaces of contact of the valves some-
times conspicuously broad.

Pedicle-valve with a more or less elevated umbo, which may vary in height in
a given species, in the type-species being high, as in Trimerella; umbonal cavity
divided into two chambers by a longitudinal septum. Cardinal area large ;
deltidial ridges and deltidial callosities not always distinctly developed ; cardi-
nal slope usually well detined, merging anteriorly into the cardinal buttress, or
umbonal septum ; in some species this slope, or subtriangular area, is longi-
tudinally divided by a furrow. The crescent is sharply impressed over the
cardinal slope ; terminal scars broad and distinct. Platform more or less
developed ; divided by the cardinal buttress, which extends nearly or quite its
entire length. Muscular impression on the platform very large, covering the

BRACHfOPODA. 41

entire surface, but rarely resolvable into separate scars. Anterior septum
indistinct, usually imperceptible. Pallial sinu.ses sometimes clearly defined.

Brachial valve with tlie umbo seldom conspicuously developed, the umbonal
cavity being usually simple and deep, but sometimes filled by a deposition of
shelly matter. Crescent sharply impressed over the narrow canlinal slope,
and produced into broad, indistinct, composite terminal scars. Platform usually
well developed iuid broadly excavate on its anterior walls, but sometimes
scarcely discernible. Anterior and lateral scars sharply defined, giving a tri-
partite appearance to the platform. Anterior septum more strongly developed
than in the opposite valve.

Type, Monomerella prisca, Billings.

Observations. The very rich material that has been before us in the study
of this genus, has added a number of interesting and previously unknown forms,
and the variations from the type-species shown by these, has made it neces-
sary to modify in some respects the diagnosis of MoNOMEUt;LL.\, as given by
Davidson and King. At the date of their work but four species were known,
and the four additional species, which, for convenience in discussing the genus,
are described in the supplement to this volume, present some important
deviations from the type-form, and necessarily broaden the scope of the genus.
Mr. Billings' species, Monomerella prisca and M. orbicnlaris, from the Guelph
limestone at Hespeler, Canada, were first illustrated by the English writers,
who also added two new species, M. Walmskdli, from the Aymestry limestone
of Gotland, and M. Lindstrmmi, from the Wenlock near Wisby The former of
these Gotland species is very closely allied to M. prisca. Indeed, we are com-
pelled to include under this latter name, American forms which vary so con-
siderably in the elevation of the cardinal area, size of the umbonal chambers
of the pedicle-valve, and the depth of the umbonal cavity in the brachial valve,
that with this broader conception of the specific characters of M. prisca, it
would be easy to consider M. Walmstedti as conspecific. The specimens of M.
prisca, from the dolomites of the Niagara group, at the Rising Sun quarries,
Wood county, Ohio ; Hawthorne, Port Byron and Cicero, Illinois ; and near

42 PAUEONTOLOGY OF NEW YORK.

Cedarburg und Grafton, Wisconsin, sliow not only the high area and deep
chambers of the Canadian types, hnt deviations tlierefrom, which, if found in
specimens nnassociated witli tlie intermediate forms, might be regarded as of
distinct specific vahie. We have, on a preceding page, called attention to
essentially similar variations in the species Dinoholus Conradi.

The cardinal area of the pedicle-valve in M. prisca is always erect, and its
subdivisions are sharply defined; a broad, usually convex though depressed
deltidium is bounded by elevated deltidial ridges merging into the areal
borders, and has the deltidial callosities or articulating (?) apophyses more
strongly developed than elsewhere noticed among the Trimerellids. On the
other hand, in M. Ortoni, the cardinal area, equally broad and high, is gently
incurved, as in Uhinobolus, and is transversely striated, but has only very fsiint
evidence of longitudinal subdivision In M. Gremii and M. ovata, this area
is low, smooth, and not subdivided, but is continued about the margins into a
broad surface of contact with the other valve. In the brachial valve of M.
prisca and M. Kingi the cardinal area is slightly if at all developed, the beak
being marginal; while, in M. Greenii, it is somewhat elevated, and, in M. Egani,
very prominently developed.

The development of the umbonal chambers depends essentially on the height
of the umbo, and the degree of its thickening; in M. prisca always extending
above the hinge-line, in M. ovata and M. Kingi they reach to the hinge, and, in
M. Greenii, rarely appear to extend so far. The undjonal cavity of the brachial
valve is subject to even greater variation, but this is more largely an individual
than a specific divergence. In the thin-shelled species, M. Greenii, this cavity
is invariably deep, but in M. prisca it appears to be frequently thickened by
internal deposition. This feature is also seen in M. Kingi, and in the single
valve representing the species, M. Egani, we have an example of this umbonal
thickening carried to an extreme.

The platform, never so strongly developed as in Trimerella, nor furnished
with vaults, is usually a conspicuous feature, but in M. Greenii it is almost
obsolete, its position being evident only from the slightly thickened muscular
scars.

BRACmOPODA. 43

Generally these muscular scars are sharply defined. Those on the platlbnn
of the pedicle-valve indicate very large organs, but in M. prisca wo ha\e
been unable to resolve them as Davidson and King liave done. In M. (ireenii,
the lateral scars are clearly outlined and limited to a comparatively small sur-
face. Their small size may be largely due to the fact that the valves of this
species were comparatively light ; tlieir position, close together on either side
of the median septum, is very suggestive of the muscular arrangement in
ScHizocRANiA In M. Orloni there appears a prominent anterior scar with fainter
laterals, bordered in front by narrow converging furrows.

On the brachial platform, the subdivision of the muscular imjjression is
always strong, producing a trilobate appearance ; .sometimes the shell is so
preserved as to show the long progressive track of the laterals and the centrals,
at others, the older portions of the scars are covered by an organic deposit
limiting the impressions to tlie area last covered by the muscular bands.

In one species, M. Ortoni, the impressions of the pallial ves.sels, both primary
and secondary, are very distinct, and this is the only instance in which the
ramifications from the main vascular trunks have been observed in this group.
MoNOMERELLA is readily distinguished from the allied genera by its two umbonal
chambers and low, unvaulted platforms. In tlie brachial valves of this genus,
and of DiNOBOLUS and Rhinobolus, the similarity in internal features is very
close, and care is required in the generic determination. In Dinobolus the plat-
forms are always vaulted, to some degree, by conical cavities, and not merely
broadly excavated on the anterior walls ; the umbonal cavity is a small, acute
depression, never filled by testaceous deposit ; the crescent is always broad, with
abrupt lateral angles. Rhinobolus possesses a very short platform, strongly
elevated at its anterior margin, and sloping abruptly backward, but there is no
evidence of its general suppression as sometimes occurs in Monomerella.

Species of this genus, like those of Trimerella, are very limited in faunal
range. The Canadian examples are all from the Guelph limestones of the
Province of Ontario ; those from the States of Ohio, Illinois and Wisconsin
are from dolomites usually referred to the age of the Niagara of New York ;

44 PAL/EONTOLOGY OF NEW YORK.

but probably serving as a taunal equivalent of the Niagara and Guelph forma-
tions. No species are known in Great Britain, those from the Island of Got-
land, and from Livonia, Russia, are from faunas cori'esponding to that of the
Niagara and Wonlock.

■"B^'

Genus RHINOBOL US, Hall. 1871.

PLATE IV II, FIGS. 7-12.

[1] 1862. Obiilus, BiLLi.vfiS. Piilaiozoic Fossils?, voL i, p. 1138, lig-. 1:')!.

1871. Triiaerella. Dai.i,. American Journal of Concliology, voL vii, p. 83.

1871. Rhynohohis, H.vll. Advance sheets (March) Twenty-thii'd Rept. N. Y. State Cal>. Nat. Hist., p.

247, pL xii, fig-. 10. 1S7S.
[?] 1871. Oboldlina, Billings. Canadian Naturalist, vol. vi. New Series, p. 220 (December).

1872. DinoboliiS, Davidson and King. Report Brighton Meeting of British Association.

1874. lYimcrella (.'), Davidson and King. Quart. Journ. Geological Society, voL xxx, p. ITil, pi. xviii,

fig. 13 ; pi. xix, figs. 4, 4a.
[1] 1884. Hhynobolus, Whitbaves. Paheozoic Fossils, voL iii, pt. 1, p. 7, jil. ii, fig. la; pi. viii, figs. 3, 3a.

Diagnosis. General form of the shell as in Trimerella.

Pedicle-valve, iu the typical species, with an elevated, solid beak, having a
broad and high deltidium, divided into a relatively narrow central area (which
may be concave or convex), and broad deltidial ridges. Crescent and terminal
scars as in Trimerella. Umbo-lateral scars sharply defined. Platform very low
and incompletely developed, consisting of a broadly V-shaped elevation, with
a raised anterior margin, and surface sloping abruptly backward to, or even
below the general curvature of the internal surface. A faint longitudinal sep-
tum extends forward from the platforui.

Brachial valve witli low, suli-niarginal, slightly curved apex, and short delti-
dium. Crescent conspicuously developed. Platform as in the opposite valve,
with the addition of a central scar, which gives the entire area a tripartite
appearance. Median septum faint.

Type, ''Rhynobolus- .? " Hall. (1871, loc. ciL, pi. xii, fig. 10.)

Orservations. The description of the genus Rhinobolus (erroneously printed
Rhynorolus) Avas based upon the interior of a pedicle-valve, characterized as in
the foregoing diagnosis. At the time of the publication of the generic term,
this valvi' had not been positively identified with the Obolus Galtensis of BiWings

liRACmOFODA. 45

(a species then known only lioin an imperfect interior of the brachial valve), as
was subsequently done by Davidson and King, Dall, and Whiteavks, but it was
simply suggested that Billings' species might prove a representative of the
same genus.

Mr. WiiiTEAVES lias given {loc. cil.) lignves oi' Rhinobolus Galknsis, which repre-
sent not only a brachial valve in entire agreement with the figures published
by Billings, Davidson and King, and with specimens in the possession of the
New York State Museum, but also a pedicle-valve, which is referred hy him to
the same species, but which does not at all agree with the original specimen of
KniNOBOLUS. It is, on the contrary, of about the same outline as the brachial
valve, with a low, incurved umbo and a very broad margin of contact, much
like that seen in the species Monomerclla ovata and M. Greenii. Should this
prove to be the pedicle-valve of the species, a doubt might fairly arise as to the
propriety of including it under the genus Rhinobolus. Mr. Whiteaves' speci-
mens are from Hespeler and Durham, Ontario, and all retain the shell, but it
does not appear that the valves have been found in connection. The original
specimen of Rhinobolus was from Gait, and before us is a very perfect
brachial valve from Elora, in exact agreement with those referred to Billings'
species, and this we are strongly disposed to consider as belonging to the same
form, on account of the complete harmony in the degree of development of the
platform and muscular scars. Our belief that these represent the same species
is further confirmed by specimens before us of a distinct species of the genus,
R. Davidsoni, sp. nov. (see Supplement), from the Niagara dolomites near Graf-
ton, Wisconsin, in which are found the same imperfect development of the plat-
forms, in association with a high cardinal area and erect beak. As already sug-
gested, the pedicle-valve referred by Whiteaves to R. Galtensis, resembles, as far as
it is known, certain Monomerellas, and it will be important to look for interiors
of this form which may lead to its correct allocation. Meanwhile Rhinobolus
Galtensis, Billings, may tentatively be regarded as the type-species of the genus.

In regard to the generic characters of this species, the opinion liekl by
Davidson and King, that they represent an extreme aberrant variation of

46 PALAEONTOLOGY OF NEW YORK.

Trimeref.la, linked to typical .specimens of the genns by species like T. Billingsf,
Diill, in which the platform-vaults are quite short, does not seem in accord with
the persistent abbreviation of the platform and the entire absence of platform-
vaults and umbonal cavities. We can, indeed, find an analogy to Trimerella
solely in the development of the deltidium of the pedicle-valve, while the
similarity to Dinobolus in the structure of the platform is more apparent, though
still remote. In the features of the brachial valve, however, the agreement
with MoNOMERELLA is by no means remote, as is seen in the marked difference
of the centntl and lateral scars Mr. Davidson afterward abandoned his view
expressed al)ove, in regard to the relations of these forms, as we learn by an
extract from a letter to Mr. Whiteaves, quoteil by the latter at page 8 of the
Pala?ozoic Fossils, vol. iii, pt. 1 :

" Although with much uncertainty this shell was placed, by Professor King
and myself, in the genus Trimerella, it is not a true Trimerella, and should
be removed from that genus. It is more closely allied to Monomerella, and
perhaps it would i)e better to retain Professor Hall's generic name of IIhynobo-
LUS for its reception."

In addition to the features already mentioned, the species of Rhinobolus show,
on both brachial and pedicle-valves, the broad terminal scars at the extremity
of the sharply developed crescent, and, in the pedicle- valves, the umbo-lateral
scars; the great trunks of the pallial sinuses are faint, though discernible.

OBSKRVATIONS ON THE DEVELOPMENT AND FUNCTION OF THE PLATFORM
IN THE INARTICULATE BRACHIOPODA.

The specialized post-median testaceous deposit which has been termed the
"platform " by Messrs. Davidson and King, occurs among brachiopoda only in
the genera Lakhmina, Lingulops, Lingulasma, Dinobolus, Trimerella, Monomer-
ella and RiiixoBOLUS ; it constitutes the principal diagnostic character of the
Family Tuimerellidje of those authors, and in so far as any of these genera pos-
sesses this feature, so far, at least, is it a Trimerellid. In its chronogenesis it

BRACinOPODA. 47

is accompanied by certain peculiar plienoniena. According to our present
knowledge its first appearance is in the little Lakii.\un'a, from the primordial
" Obolus-beds," in the Salt-Range of India, but in American faunas, where the
development of the group is best ex'cmplified, it is first met in Dinobolus (in
external features the most oboloid form of the group), in the later faunas of the
Lower Silurian; Black River, Trenton, Galena. Thereupon follow in the still
later fauna of the Hudson group the more pronounced linguloid genera, Lingulops
and LiNGULASMA. Not, however, until the introduction of the Niagara or Wenlock
fauna does the entire group, with the exclusion of the inceptive linguloid forms,
reach its culmination in specific and individual development. The magnesian
deposits constituting the Guelph and Gait limestones of the Province of Ontario,
and the Niagara limestones of the interior of the United States, seem to have
been accumulated under conditions favorable for the rapid increase of the.se
animals, and yet, notwithstanding that in the limestones of the Niagara of New
York, the Aymestry and "Wenlock uf England, and the Etage E-e,, in Bohemia,
these fossils have been found l^it sparingly, the equivalent faunas of the Island
of Gotland, involved in essentially the same physical environment, produced
certain of the genera in vast numbers. This was the period of the culmination
of the Trimerellids, irrespective of their surroundings. With the disappear-
ance of this fauna, the platform-bearing brachiopods virtually became extinct,
and we have as yet no trace whatever of the occurrence of this peculiar feature
at any later date, or in any other group of these animals.*

In the genus Trimerella only, do we meet with a constant development of the
platform in both valves, as a compound vaulted arch ; in the other genera it is
a solid plate, always showing a tendency to excavation on its more or less con-
cave anterior walls, while Dinobolus furnishes frequent in.stances of this tendency
being carried further toward the development attained in Trimerella, though
its vaults, when developed, are small, narrow and constricted, by no means bear-
ing the same dimensional proportion to the platform as in the latter genus.

* In some genera of tlie .articulate brachiopods the anterior and lateral edyes of the muscidar urea is
at times conspicuously elevated, foi- example, frequently in LEPxaJXA, Sthoi'Homena, Strophooonta, and
Stbbptorhynchds. To what extent this elevation is of the same nature and due to the same causes as the
platforms of the'Trimerellids, is yet to be determine<l.

48 PALJEONTOLOGY OF NEW YORK.

Authors have suggested various functions lor the chambers of the phitforni.
LiNDSTR()M* regarded them as having been occupied by the adductor mus-
cles; under this interpretation the arclies would be conceived as the
result of the progressive growth of tlie muscular fulcra or excessive
shelly deposition about the base of the muscular bands. Davidson and King
conceived them, "from their contiguity to the usual locale of the liver,
to be the most likely receptacle for the divisions of this organ."f The same
authors have also quotedj: from a private letter of Mr. Whitfield, an
opinion to the effect, that on account of the great size of the muscles re-
quired to work these ponderous shells, there would, of necessity, be a displace-
ment of the essential organs, and that, under the force of this necessity, the
platforms may have been developed to raise these large muscles from the center
of the valve, and let the sexual organs pass beneath them. Such suggestions,
however, can apply primarily, and in their entirety, only to Trimerella, Lakh-
MiNA, and such forms of Dinobolus in which the platforms are vaulted. These
do not constitute tlie largest, or a fairly representative portion of the group,
all the other genera, and Dinobolus usually, having the platform solid.

In order to apprehend more satisfactorily the functions of these specialized
parts of the shell, we nuiy turn our attention briefly to the relations of the
platforms in the linguloid genera, Lingulops and Lingulasma, to the muscular
scars and fulcra in the true Lingula.

While treating of the genus Lingula, we have adverted to the lact, that tlie
anterior and central muscular scars {k, h, of the pedicle-valve ; j, h, of the
brachial) may produce either distinctly localized impressions, indicating the
space actually covered by the ends of the muscular bands at the time of the
death of the animal, or may l)e nuich elongated, extending over nearly the
entire visceral region, as seen in />. Whitii, L. Elderi, L. punctata, L. lamellaia,
and others (see Plates I and IV k) ; tliese large impressions indicating not cor-
respondingly great muscles, but the advancing path of the respective bands as
the shell has progressed in growth, only the anterior portion of the scar repre-

* Om Bi-a<;hiopo<ionslagtet Trinierella.
t On Uie Ti-imerellids, p. 134.
X On the Triinerelliilie, p. 135.

BRACHIOPODA. 49

senting the last place of attachment. In L. anatina these median scars are
usually localized and excavated on the mariiin of the shelly thickening which
covers the visceral area, and it appears that this thickening of the shell is
largely due to the progressive deposition of testaceous matter about the inser-
tion of the muscles; where the members of a muscular pair come into juxta-
position along the axis of tlie shell, the natural result of the union of these
depositions is a median septum.*

Among the Lingulas which have passed under oui- observation, whether of
fossil or recent species, it is seldom that any tendency is shown by these scars
to become otherwise than thus terminal and excavated.

The first deviation in this respect toward the formation of a platform is
found, without any known transitional forms, in Lingulops itself; not in the
brachial valve, which actually possesses this organ in an incipient stage, but in
the pedicle-valve as elsewhere described and illustrated. Here the muscular
scars, which indicate large organs for such small shells, are concentrated well
toward the middle of the valve, and their anterior edges are distinctly and
abruptly elevated, placing the scars, by virtue of the stronger deposition of the
shelly matter about the anterior edge of the area of insertion, upon, instead of
beneath, the median thickening of the shell. How much of this change may
be due to the increase in size and in the work required of the nmscular
apparatus does not appear in the minute and fragile shells constituting
this genus, except that the impressions are large and all very sharply de-
fined (a most striking feature in nearly all of the genera of platform-bearing
shells is their great size and weight, necessitating powerful muscles to work
them). In view of the close relations of the characters of this valve to those
of LiNGULA, we may venture to predict the discovery in the earlier paleozoic
faunas, of some linguloid shell which will sliow in both valves just the
stage of deviation from Lingula toward Trimerella that is indicated

* It is not the intention to give this suggestion so broad an aiii>li(-ation as to include all such septal
phenomena in the brachiopods. It does apply to Linr/ula anatina, and to all Lingulas, as far !is we are
awaie. whether iXv se|ita be axial or lateral ; but it would be difficult to thus explain the oi-igin of the great
anterior extension of the septum into the biachiocccle, as seen in Linghlasma, Trimerbll.\, etc. Such great
vertical plates may. however, have had their source in septa of the character of those in Lingdla. Among
the articulate brachiopods, the origin of median septa from similar causes is often apparent.

50 PAL.¥.ONTOLOGY OF NEW YORK.

bv the pedicle-valve of the earlier species of Lingulops (/.. Whitfieldi, L.

Nonvoodi).

The brachial valve of this genus, with its little platform well defined, indi-
cates a peculiar phase of accelerated development over its companion, and this
same relation is manifested in L. Granti, which has the platforms developed in
both valves, and also in Lingulasma, in both of which the brachial platform is
the larger. The same feature occurs to some extent in the other genera.

It therefore appears probable that the inception of the platform is due to the
sli"-ht variation indicated in the mode or rate of formation of the muscular
fulcra in Lingula, and this may itself have been due, in part, to a simple in-
crease in the size of the muscular bands.

In Lingulops Whitfieldi, the development of the platform of the brachial valve
is not so far advanced as it appears in the other species of the genus; never-
theless, its surface is divided by a longitudinal depression, its anterior edge
distinctly elevated, and its anterior wall slightly concave. In L. Norwoodi the
brachial platform, in its relative proportions, is almost a miniature of that in
Trimerella, being elongated, narrow, and divided for its entire length by a
median depression, but not hollow, though with its anterior walls more concave
or excavated than in its congener ; and in L. Granti, of the Niagara fauna,
essentially similar characters are manifested.

Another consideration concerning the origin of the platform is suggested by
the chronological order of appearance of these fossils. The forms which have
been just considered, and which indicate the line of derivation from Lingula to
Trimerella (the latter genus being assumed to represent the climacteric develop-
ment of the platform), are the predecessors of Trimerella, Monomerella and
RiiiNOBOLUS; not remotely from afaunal standpoint, but actually, by a great lapse
of time ; the former are from tlio Hudson group, the latter from the Niagara
faunas. Lingulops, strangely enough, has spanned this great interval, reappear-
ing in the Niagara fauna witli some important modifications, viz., the develop-
ment of the nuiscular area of the pedicle-valve into a well-defined platform ;
possibly, also, the obliteration of the arched posterior scars. And Dinobolus,
though attaining a culmination of development with its allies in the Niagara

BRACHIOPODA. 51

fauna, dates as far back as the first introduction of the Trenton and Caradoc
faunas in America, thus preceding in time the linguloid forms of our series.
It therefore appears that this member of the group has received from some
earlier, and probably different source, the characters which nuike it the nearest
ally of Trimerella. Dinobolus is the only member of this family with an oboloid
form ; its shells were mucli lighter, and may prove to have been less calcareous
than in the rest of the group, not including Ling0lops and Lingolasma among
the Trimerellidge as constituted by Davidson and King.

The genus Obolus pi-esents an interior so strikingly similar to that of Dinobo-
lus, that the first known species of the latter genus, D. Davidsmi, was for many
years referred to Obolus, by .so acute an observer as Mr. Davidson himself The
essential difference, however, between Obolus and Dinobolus is precisely that
which we have just noticed between Lingula and Lingulops, i. e., the central
"spectacle-scars" in Obolus are excavated and not elevated, lying, as in Lingula,
at the anterior margin of the thickened visceral area of the shell, while in Dino-
bolus they are elevated and upon the platform. The successive transition stages
from the one form to the other are not so clearly demonstrated as in the line of
descent from Lingula. Attention, however, may be directed to the species de-
scribed as Obolella desiderala by Mr. E. Billings, the shell upon which Mr. S. W.
Ford has established the genus Elkania. This is a species which attains about
the size of Obolus ApolHnis, Eichwald, and is larger than the Obolellas and Lin-
narssonias usually found in the associated faunas. In its brachial valve the cen-
tral and lateral muscular scars are elongated, as usually in the Trimerellids, rather
than localized as in Obolus, and are raised upon a well-defined platform, which is
situated quite in the posterior or cardinal portion of the valve. The develop-
ment of the platform in tliis valve is considerably in advance of the progress
made in the opposite valve in the same direction, precisely as is the case in
Lingulops. Tiie pedicle- valve, however, shows that the corresponding muscular
impressions are distinctly elevated, and, in front of the solid sub-triangular
plate on which they rest, is a very deeply depressed area occupying the central
portions of the valve and corresponding to the deep concavities having a
similar position in all the Trimerellids. A very conspicuous feature of this

52 PALEONTOLOGY OF NEW YORK.

valvo is the great post-median depression, which was considered by Mr. Ford
as representing a pit for th(> reception of the pedicle, but the necessity for so
hirge an organ in so small and light a shell, as this would imply, does not appear,
and we have regarded it as the correlative of the central muscular scar in the
opposite valve. From the anterior end of this scar are two narrow diverging
furrows, the function of which is not understood, and the analogues of which
have not been observed in any of the oboloid or indeed among the inarticu-
late brachiopods in general, save in the species Monomerella Greenii, where they
attain the same relative development as in Elkania. It is possible that these
furrows are specialized sinuses leading from the genitalia to the pallial vascular
system, and performed the function of oviducts; their juxtaposition to the pallial
trunks indicating some such office. Of still further importance in Elkania is
the narroAv furrow in each valve passing around the muscular area just within
the cardinal margin, terminating laterally in a more of less well defined scar ;
in other words the first appearance, in the oboloid genera, of a distinctly de-
veloped crescent. As to their appearance in time, Obolus, Elkania and Ding-
bolus are successive.

If we have, thus, correctly suggested the source and development of the
platform in the Trimerellids, we are confronted with the interesting phe-
nomenon of a similar resultant attained along different lines of development.
This may be expressed by the following diagram;

^^' Obolus Elkania ^^..^

Obolclla -^'"^ ^^~^DiiKibolus-^-_^^

? (Laklimina) _ Tiimerella.

Lingulella ._. /^...^Monomerella Rhinobolus.

Lin^ula Lini,'-iilops Ling-iilas^ma^ '

It is probable that the progenitor of Obolus will be found in Obolella, or some
of the closely allied genera, and our present knowledge of Lingulella is such
that, as elsewhere observed, it nnist he placed in juxtaposition to Obolella,
while evincing a deviation toward Lixoula. The two are, in all probability,
but a few removes from their common ancestor, Avhich may be looked for in
the earliest primordial faunas, unless its existence was limited to obliterated

BRACHIOPODA. 58

faunas of still earlier date. IIhinobolus has the aspect of a degenerate Triui-
erellid, marked by the general ol)solescence of the characteristic features of the
group. In L.-VKHMiNA, we have evidence that the platforms attained a con-
siderable development before the introduction of Silurian faunas. Features,
which in American faunas appear to have developed slowly, and whose different
stages can be satisfactorily traced, seem to have been specialized with great
rapidity in this obscure fossil. It is not necessary to assume that this fossil
from a distant fauna, now regarded as of primordial age,* will materially
modify the conclusions expressed in the foregoing diagram, derived from the
studj' of American faunas.

Having indicated that the inception of the platform was probably due to aug-
mented muscular energy and concomitant increased secretion of muscular
fulcra, we may revert to the consideration of the function of this organ in its
highest development, and to the inquiry, whether this attainment may have
been acquired alone by the constant action of the forces named, or has been
aided to this result by the accessory action of other organs.

Whether or not the platform be hollow as in Trimerella and LAKHMrNA, and
sometimes in Dinobolus, or solid, as usually in Dinobolus, and always in the
other genera, there is invai'iably a manifest tendency toward its excavation. The
anterior walls are always concave ; in Monomerella the concavity of the plate
is deep, the anterior moiety being turned with a steep slope toward the cavity
of the shell ; furthermore, the shell itself is much depressed beneath this
projecting wall and on either side of the anterior median septum into which
the platform is continued. The same features are seen in the brachial valve
throughout these genera.f Even in Rhinobolus, all that is lett of the platform
is turned upward and inward at this sharp angle. In the pedicle-valve, how-
ever, this inclination of the platform, the excavation of its anterior walls and

* See iiagfe 29.

t Mr. TJlrich describes a peculi.ir structure in the jilatform of Lisgula.sm.4. He says: "The cost of the
interior which furnished the gutta-percha sriueezes represented by figrs. it and m" (see I'l. II, Hg. 19), "orijj-
inally preserved much of the shell and all of that pertaiiiingr to the platform. This was carefully removeil,
and during the process it w.ns noticed that the platform consisted of numerous cup-shaped laininie placeil
within one anothei-, and so that an open space was left between each and the preceding and succeeding ones "
(American Geologist, vol. iii. No. 6, p. 386. ISS9).

54

PALEONTOLOGY OF NEW YORK.

depression of the surrounding surface of the shell is never so marked ; the
platform itself is of less size throughout, and we have noticed that in the course
of its development it does not make its appearance so early as in the brachial
valve. The lead held by the brachial valve in this respect, as shown in Lingu-
LOPS and Elkania, is maintained throughout the entire history of the organ.
The cause of this is not far to seek. In Lixgula, the anterior portion of the
visceral region lying directly in front of, and
behind the insertion of the anterior muscular
bands, is occupied by the liver. In L. anatina,
rather the greater portion of this body lies
behind these muscular scars, but in Lingulops
there is a general posterior concentration of all
these muscular bands. In such a case the retro-
gression of the muscles could not force the liver
into a more contracted space or otherwise
displ.ace it than to change its relative position
and leave the large muscular bands behind it.
This organ (the liver) is large, and lies mostly
on the dorsal aspect of the animal, the surface
there covered by it, in L. anatina, being con-
siderably more extensive than on the opposite
side. It is also distinctly bilobed by the longi-
tudinal septum on the brachial valve. The
pressure of this oi'gan against the anterior edges
of the area of muscular implantation must have been of significance in induc-
ing the foi-mation of the anterior elevated margins of the muscular scars, and
in this pressure, continued as a constant force in both valves, though less in-
tensely in one than in the other, may, perhaps, be found an efficient cause for
the abrupt termination of the muscular area, its elevation, its concave anterior
walls, and, eventually, its complete excavation, as well as the depression of the
adjoining surfaces of the shell.

In discussing the genus Ding bolus, attention has been directed to the tendency

Fig. 17. Lingula anatina,
Ab oral aspect, sliowiug tlio arraiigenienl ul" Ihe
viscera on the inner surlaoe of tlie brachial
valve (after King).

h, central scars. a, liver.

j, anterior lateral 6, genitalia.

scars. e, alimenlarv canal.

BRACIIIOPOjDA. 55

occasionally manifested in both valves of the species to form two or three
vaults on either side of the platform. In animals of the size indic;ited by these
shells the lobation of the liver may have been so strongly developed as to pro-
duce this peculiar effect in the excavation of these cavities. Admitting the
sequestration of the liver in Trimerei.la, a freer play would undoubtedly be
left to the muscles and greater opportunities of development, and this fact will
have had both a direct and inverse bearing on the size attained by both the
platform and the shell itself.

In regard to the great umbonal chambers of the pedicle-valve in Mo.nomicr-
ELLA, and their lesser development in Dinobolus and Trimerella, they have pos-
sibly served a similar function to the platform-vaults, by removing the delicate
genital organs from dangers which might arise from the action of the muscles.
In Lingula anatina, these organs lie normally in the median and posterior portion
of the visceral region, pressing backward against the post-parietal wall, and are
placed mostly on the ventral side of the body. In offering an interpretation
of the arched posterior scar in Lingulops, Davidson and King suggested that the
middle sinus of the arch might have been produced by the- umbonal muscle
pressing against the parietal wall, and the lateral sinuses have been due to the
pressure of the ovarian lobes against this muscular wall. Were this the case
in the genus where all these features are in an initial stage of development, it
would readily be conceived how by this constant pressure the genital organs
may have developed the umbonal cavities for their own protection.

Genus LINGULELLA, Salter. 1866.

ri.ATK U, riGS. 1-13.

1852. Lingula, McCoy. Annals and Miig-azine of Natural History, Second Series, vol. viii, p. 40.').

1852. Lingula, McCoy. British Palxozoic Fossils, p. 252, pi. 1 L.

1859. Lingula, Salter In Murohison'.s Siluria, Fourth Edition, p. 43.

1866. Lingulella, Salter. Mem. Geolof,ncal Survey of Great Britain, vol. iii, p. 333.

1866. Lingtdella, Davidson. British Silurian Brachiopoda, p. 55.

1867. Lingulella, Salter. Quai-terly Journal Geological Society, p. 340.

1868. Lingulella, Davidson. Geolofe'ical Magazine, p. 303.

1871. Lingulella, Davidson. British Silurian Brachiopoda, p. 336.

56 PALMONTOLOGY OF NEW YORK.

(?) IS12. Lingula, Emmons. Geology N. Y. ; Rept. Second District, p. 267 (not fig'. 68).

(?) 1S47. Lingula, (Coxrad) Hall. Palaeontology N. Y., vol. i, p. 3, pi. i. tig. 2.

lS-i7. OrhicvJa, Hall. Piilneontology N. Y., vol. i, p. 290, [il. Ixxix, tig.s. 9 a, fc, c.

(?) 1860. Lingula, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist , p. 76, tig. 1.

ISBl. Lingula, Hall. Annual Report Geological Survey of Wisconsin, p. 24.

1862. Lingula, Billing.s. Palajozoic Fossils, vol. i, ji. 71, tig. 64.

1SG3. Lingula, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., pp. 126, 127, pi. vi, figs. 4-8.

1867. Lingula, Hall. Transactions Albany Institute, vol. v, p. 103.

1871. OhoUlla, Billings. Canadian Naturalist and Geologist, vol. vi, p. 218.

1871. OhuUlla, Ford. American Journal of Science, vol. ii, p. 33.

1S71. Linguldla, AIkkk. Proceedings Academy of Natural Sciences, Phila., vol. xxiii, p. IS.i.

1873. Linguhlla, Hall. Twenty-third Rept. N. Y. State Cab. Nat. Hist., p. 245, pi. xiii, fig. 5.

1874. Lingulellaf , Billings. Paljeozoic Fossils, vol. ii, p. 57, fig. 36.

(?) 1875. Lingulella (Dignoinia f). Hall and Whitfield. King's Re^iort U. S. Expl. Fortieth Parallel, p.

206, pi. i, figs. 3, 4.

1875. LinguU'p'iii, Hall and Whitfield. King's Rept. U. S. Expl. Fortieth Parallel, p. 232, pi. i, tig. 8.
1878. Lingulella, Foed. American Joui-nal of Science, vol. xv, p. 127.

(?) 1878. Lingula, Whiteatks. Amei-ican Journal of Science, vol. xvi, p. 226.

1882. Linguhlla, Whitfield. Geological Sui'vey of Wisconsin, vol. iv, p. 334, pi. xxvii, figs. 6. 7.

1884. Lingula? , (M.\tthew) Walcott. Bulletin No. 10, U. S. G^logical Survey, p. 15, pi. v, tig. 8.

1885. Lingulella, Matthkw. Illiistr. Fauna St. John Group, No. 3, pp. 33, 34, pi. v, tigs. 7, 8.

1886. Lingulella, Walcott. Bull. No. 30, U. S. Geol. Surv., pp. 95, 97, pi. vii, figs. 1, 2 ; pi. viii, fig. 4.

1887. Lingulella, Walcott. American Journal of Science, vol. xxxiv, p. 188, pi. i, fig. 15.
1889. Lingidella.yiM.coTT. Proceedings Uniied States National Museum, 1888, p. 441.

Diagnosis. "Shell nearly equivalve, broad-oblong, the ventral valve pointed,
with a distinct pedicle-groove. Muscular scars strong, nearly as inOBOLUS, but
the pair of anterior retractors are more linear apd the sliding muscles small,
and not quite external as in Obolus" (Salter. Memoirs Geological Survey of
Great Britain, vol. iii, p. 333. 1866).

Type, Lingulella Davisi, McCoy.

"The name Lingulella was first introduced about 1861, with the late Dr.
S. P. Woodward's lull consent; and the name appears at p. 9 of Sir Roderick
Murchison's Address to the Geological Section of the British Association,
Manchester, 1861 ; but it is only in Mr. Salter's Appendix to the ' Memoir on
the Geology of North Wales,' that the genus is for the first time described"
(Davidson, British Silurian Brachiopoda, p, 55. 1866).

Observations. Under the discussion of the genus Lingula, attention has
been directed to the peculiarities of the cardinal area in the type-species, L.
anatina, and its close similarity with that of Lingulella David. The necessity
of great caution in assigning generic character from these features alone has
also been expressed. In Lingula the deltidium bears a broad pedicle-groove,

BRACHIOPODA. 57

while in Ltngulella the opeuins for the passage of the pedicle is a sharply de-
fined slit, not merely making a de^wession upon the sur-
face of the cardinal area, but apparently penetrating it
from apex to cardinal line Varying conditions of pres-
ervation will often make the determination of tiiis feature ,^
difficult ; but, aside from the character of the cardinal /
area, there is little known of the type-species of LiNi;u- ''',^M%„SSXw;'ioi;f""
LELLA which can l)e satisfactorily regarded as of generic value.* Mr. Salter
suggested a similarity in the muscular scars of L. Bavisi, ami those of Obolus
and Obolella ; Davidson, however, was unable to find e.xamples of the species
showing these impressions satisfactorily,! but called attention to the coarse
puncta3 over the visceral surface of one individual.

The generic term Lingulella has been used with considerable freedom by
both American and English writers, but while there nuist remain a degree of
uncertainty in regard to the correct generic character of many species now in-
cluded under this name, there are a few primordial forms which are pretty well
understood, both externally and internally; but whatever conclusions in regard
to the generic features of Lingulella are derived from the study of these,
must be dependent upon the results of future investigations upon the type-
species, L. Davisi.

Mr. C. D. Walcott has giveni figures of Linguklla Ella, Hall and Whitfield,
which show not only the characteristic cardinal area and pedicle-slit, but
give very distinctly the character of the muscular impressions on both valves.
There will also be found on Plate I, figs. 1-4, of this volume, illustrations of
the interior of both valves of Linguklla calata. Hall (Orbicula, Hall, 1847,

•* Dr. King was strougly disinclined lo admit ilie term Li>(itLiiLL.\. In his work mioii llie •• Characlui'S
of Lingula aiMtirm," he says: "The deltidium is a vai-iable structure iti Palliobr.inchs generally ; and
its modifications are far from being understood. As regards the deltidium in the genus undei- consideration
[LiSGCLAJ, one circumstance is remarkable: it has been in a great measure overlooked ; at least 1 can find
little, or rather no notice of it in the wiitings of previous observers. It is this ovei-sight which led the late
J. W. Salter to institute his genus Li.ngulei.la, which he typified with the Cambrian Lingula Davisi, under
the belief that its 'pedicle-gr-oove' and ' hinge-area ' do not charactei'ize any species of the old BruguiJrian
genus" (Ann. and Mag. Nat. Hist., Fourth Ser., vol. xii, p. 14. 1873).

t Silurian Brach., p. 55.

J United States Geological Survey. Bull. 30, j.l. vii, fig. 2 ; .in.l pi. viii, figs. 4 a, b, c. 1886.

58 PALAEONTOLOGY OF NEW YORK.

Obolella ;in(l Lingulella, Ford), which show a close agreement in the internal
characters of these species.

In the pedicle-valve the lateral scars make the long sweeping curves so
characteristic of Obolella, while the centrals, more or less coalesced, produce a
broad, somewhat tripartite scar. In
the brachial valve of L Ella, appear JB^a ^I
to be two diverging lateral scars, ex-
tending about one-half the length of the
shell, and incurving at their anterioi- ^"'»"'''""^f^'^«:'^\!f^^™';,^^'^

«.-.,1o +rnt-oiTl tlTO i.ir>i-o nnnwnipiimi* •lull FlO. 19. Dorsal aspect, showing pedicle-area. FiG. 20. Inter-
enUStOWaiU tnemoie conspicuous ami „ai castor pciliclevalve. fig. 21. internal cast ofl^niclualvalve.

apparently compound central scar. Essentially the same characters are seen in
the brachial valve of L. ccRlata, accompanied by posterior lateral scars, which
occupy a position homologous with the terminal scars in the Trimerellids. An
additional character is given to the muscular scars of the brachial valve in Mr.
Walcott's figures of his .species, Lingiilella Granvillensis* in which there
appears, near the center of the shell, a faintly defined, bilobed scar, continued
anteriorly into an oval impression. These represent the " anterior adductor
mu.scular scars, and aLso what may have been the adjustor muscular scars "f
or the anterior laterals and the centrals of Lingula. This feature constitutes
a conspicuaus difference from the obolelloid character of these impressions
in the brachial valves of the other species cited, and it will be important
to verify the character. The pedicle-valve of this species shows the straight (?)
diverging ridges similar to those in L. Dawsoni-X

Figures have been given by Mr. Davidson, showing the muscular scars in the
species L. ferruginea, Salter,§ and L. lepis, Salter.|| In both these species the
elongate, more or less curved laterals are apparent, enclosing a compound central
scar not essentially differing from that in L. Ella, though more sharply outlined.

* Amei-ican Journal of Science, voL xxxiv, p. 188, iil. i, iijj. 15 a. 1887.

t 'Walcott, loc. cit.

I By the fiivoi- of Mr. G. V. Mattukw wo ai-e enabled to give an origiu-al figure of the interior of this
species taken from the specimen rejiresented in his " Ilhistrations of the Fauna of the Saint John Group,"
No. 3, )il. V, fig. 9 d (Trans. Roy. Soc. Canada, Sec. iv. ISS.")). We have not observed the sharply defined
muscular inijiressions represented by Mr. Maithew.

§ Mon. Brit. Sil. Brach., pi. xlix, figs. 33a, Z'm. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, fig. 3a. 1868.

I Mon. Brit. SiLBnich.,pl. .xlix, fig. 31a. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, fig.s. llandlla. 1868.

BRACHIOPODA. 59

As long as our knowledge of the interior characters of Lingulella is limited
to the few species cited, the genus may tentatively include such forms as have
shown the high cai'dinal area and the distinct pedicle-slit. It is, liowever, in
a broad sense, characteristic of the first or primordial faunas, nnd it has not
been satisfactorily demonstrated that any species outside these faunas can be
safely referred to the genus. Lingulella loivensis, (Owen) Whitdeld, is a proper
LiNGUL.\; Lingulella Cincinnatiensis, Hall and Whitlield, probably belongs to the
same genus. The Lingula paliformis, Hall, of the Hamilton shales, has a distinct
cardinal area, an apparently sharply defined pedicle-slit, with Hiint linear muscu-
lar or septal scars. It does not appear to be a true Lingula, and, with our present
knowledge, it is impossible to discover wherein it differs from Lingulklla.

This geims has proved much more abundant in American than in European
faunas, but of the twenty-five or more species which have appeared in American
literature under this generic designation, fully two-fifths should be eliminated ;
while, on the other hand, some species passing current under the genus Lingula
may eventually prove to be Lingulella.

Genus LINGULEPIS, Hall. 1863.

I'LATE I, FIGS. 33, X.

1847. Lingula, (Co^■KAD) Hall. Pal:eontolo{fy N. Y., vol. i, p. 8, pi. i, fig. 3.

1851. Lingula, Hall. Foster and Whitney's Rept. Geol. Lake Superior, p. 204, pi. x.\iii. fig-. 2.

1852. Lingula, OwBX. Rept. Geol. Surv. Wisconsin, Iowa and Minnesota, p. 583, pi. 16, figs. 4, G, S.
1863. LinguUpis, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., p. 129, pi. vi, tigs. 12-16.
1875. Lingulepl", Whitfield. Ludlow's Rept. Reconnais. Black Hills, p. 103.

(?) 1876. Lingulifpis, N. H. Winuuell. Fourth Ann. Rept. Geological Survey of Minnesota, p. 41, fig. 6.J

1877. Lingulepis, Hall and Whitfikld. Kinjr's Rept. U. S. Expl. Fortieth Parallel, pp. 206, 207, 232.

1877. Lingulepis, Whitfield. Prelim. Rept. Palaeontology Black Hills, jip. S, it, jil. ii, figs. 5-0.

18S2. Lingulepis, Whitfield. Geology of Wisconsin, vol. iv, )). 169, pi. i, figs. 1, 2.

1884. Linguhpis. Whitfield. Bull. American Museum of Natural History, vol. i. No. h, p. Hi.

" Shells linguloid, inequivalve, equilatertd, oval-ovate or spatulate ; muscular
impression in one valve, llabelliform ; in the other, tripartite, the lateral divi-
sions larger. Shell corneous, phosphatic."*

Type, Lingula pinniformis, Owen.

Since the original description of this genus, little has been added to our
knowledge of its characters. The number of species that can be assigned to

* Hall. Sixteenth Report New York State Cabinet of Natural Histoi-y, p. 126. 1863.

60 PALAEONTOLOGY OF NEW YORK.

the group without hesitation is (juite small, and if the generic features of the
type-species L.pinniformis, are strictly adhered to, it may be necessary to restrict
the specific representation to very narrow limits. The original species is the
most thorough-ly understood in both exterior and interior details. The ex-
ternal character of the shell itself, when both valves are present, allows of
a ready distinction from all known forms of the genus Lingula. The pedicle-
valve bears a long, attenuate rostrum, which extends far ])eyond the apex of
the opposite valve. This appears to have been open on the lower side for its
entire length, for the passage of the pedicle, though we have no conclusive evi-
dence that it may not luive been partially covered by a thin deltidium of similar
character to that in Lingula anatina. The brachial or dorsal valve is broadly
ovate in outline, having an obscure beak and a general form which would be
in precise agreement with that of the opposite valve, were the rostrum of the
latter truncated at its base. The separated valves of L. pinniformis occur in
great quantities in the Potsdam sandstone at the Falls of St. Croix, Min-
nesota and Wisconsin, crowded together to the exclusion of any other fossil, and
there can be no doubt that the valves described in the Sixteenth Report of the
State Cabinet of Natural History, as dorsal and ventral, are such, although no
specimen has been seen in which the valves are in their natural juxtaposition.
The muscular impressions of the pedicle-valve may be determined with
tolerable accuracy. A single large scar, occupying the entire umbonal region,
is produced anteriorly into two narrow lateral
branches, extending for about one-half the
length of the shell. Between them and con-
tinuous with their po.sterior portion, lies a
central scar, not extending so far forward, but
together with the lateral branches giving the

.. 1 . . , , , . ,. FrGS 'JJ. 23. Lingulepis pinniformis.

entire muscular impression a strongly tripartite M.nterai sc.ais. c, ctntiai. s, septum.
character. Tlic homology of these scars with those of Lingula is not readily
apparent, although there is a degree of similarity which is quite strongly shown
in the outline of the central scars. Probably the entire muscular impression
would, under perfect preservntion, be resolvable into more detailed scars, but

BRAClilOPODA. 61

there is no doubt that the conspicuous laterals correspond more or less exactly
-with tlie laterals, and the central scar with the centrals in Lingula. Lingulkpis
also bears a broad and low median ridge, elevated along its margins and de-
pressed in the middle, similar to, hut fainter than that in L. anatina. Although
the similarity to Lingula in these respects is evident, a much closer homolog}'
is found in the muscular scars of this valve of Lingulkpis and that of Lingulella.
This is seen in the crescentic laterals and the prominent central in Lixc.ui.ki.la.
In Obolella, the posterior coalescence of these scars is even more prominently
developed than in Lingulella.

In the muscular scars of the brachial valve, the iHvergence from Lingula is
still more marked. These impressions make a conspicuous Habelliform scar,
extending medially about one-half the length of the shell. The central portion
of this scar is accompanied on either side by broader, partially resolvable lateral
scars, all the subdivisions of the impression coalescing in the umbonal region.
Here the crescentic laterals of Lingulella and Oisolella are quite absent, but the
posterior coalescence of all the scars into one broad and ill defined impression,
is a feature noticeable in all of these genera. Thus the genus Lingulepis affords
an important connecting link Itetween Lis.gula' and Lingulella in the direct line
of relationship to Obolella and its allied genera.

The shell-structure of Lingulei'is is, presumably, closely similar to that of
Lingula, and, as usually in that genus, its surface-ornamentation is uniformly
of concentric lines. L. pinniformis also shows a few faint radiating lines, which
are more strongly developed on the internal surface over the anterior portion
and on the interstitial lamelliB of the shell.

The genus, as far as known, is represented only in American primordial
faunas ; L. pinniformis, of the Potsdam sandstone of Minnesota and Wisconsin,
finds a closely allied species in L. a/itiqua, Hall, of the same Ibrniation in New
York. Two species, L. cmeolus and L. perattenuata, have been described from
the Black Hills, by R. P. Whitfield,* and in the same year Hall and Whit-.
FiELDJ referred three species to this genus, L. Ella, L. Mara and L. ? minuta.
The first of these has since proved a Lingulella, and it is probable that the

* Preliminary Kept. Geology of the Black Hills. 1877.

t King's Report United States Geological Exploration Fortieth Parallel.

62 PALAEONTOLOGY OF NEW YORK.

other two are to be referred to the same genus. Mr. Whitfield* has also de-
scribed a species, L. minima, from the Potsdam sandstone of New York. Adding
to these the L. Morsensis {Mnrsii) of N. H. Winchell,! we find that the genus
is thus far represented by six species, but of all these the interior characters
of the typical species only are satisfactorily known.

Genus BARROISELLA, gen. nov.

PLATE II, PIGS. 14-1(!.

1S68. Liiiffitla, Meek and Wortiien. Geological Survey of Illinois, vol. iii. p. 437, pi. xiii, tig-. 1.

enf. 1SB6. Linr/ula. Davidson. British Silurian Brachiopoda, p. 42.

ciif. 1870. Linr/ida, Wi.nohki.t,. Proceedings American Philosophical Society, vol. xiii, p. 248.

ruf. 1S73. Genu.s?, Ki.\<i. Annals and Magazine Natural History, Fourth Series, vol. xii, p. 13.

cnf. li<S\. Lintjula? , D.\vid.son. Brachiopoda Budleigh-Salterton Pebble-bed, p. 361.

/-»/. 1SS7. Lim/ula (GlnlthVm). Viw.cn. Zeitschr. der deutsch geolog. Gesellsch., vol. xxxix, p. 392.

Diagnosis. Shell externally as in Lincula.

The pedicle-valve bears a high cardinal area, which does not appear to be a
shelf, as in Linoula and Lingulella, but a thickened triangular plate, which is
divided l)y ti broad pedicle-groove. On the basal margin of the cardinal area,
at the angles made by the lateral margins of the pedicle-groove, is a pair of
bosses or condyles, which have undoubtedly served either as muscular fulcra,
or, to some extent, as points of articulation with the opposite valve. The
interior of the pedicle-valve shows a subquadrate depressed area lying directly
beneath and almost in continuation of the pedicle-groove ; this may represent
the umbonal muscular scar. From its ante-lateral angles diverge two sharply
defined, linear depressions, which extend about one-fourth the length of the
shell and end abruptly. From outside and behind the extremities of these
depressions, begins a pair of long, curved furrows, which ;ire composed of two
shorter curves, the posterior rounding over the extremities of the linear de-
pressions referred to above, the anterior tuid longer curves gradually approxi-
uKiting and n(>arly meeting at a point tibotit one-third the shell's length from
the anterior margin. These; furrows are accompanied by low ridges along their
inner margin. A low median ridge, with elevated edges, begins at the posterior
umbonal impression, and continues to the center of the valve, widening near

* Bulletin American Museum of Natural History, vol. i, No. ■'5, p. 141, pi. xiv, figs. 1, 2. 1S84.
+ Geology of Filhnoi-e County, Minnesota. 1876.

BRACinOPODA. r,3

its anterior extremity. Just brliind its termination is a pair of small, usually
indistinct muscular impressions, prol)ably the scars ol" the central nmscles.

In the brachial valve the beak is scarcely prominent, and the muscular mark-
ings are essentially as in the opposite valve, but more sharply developed.
Beneath the beak is a fahit umbonal scar, the diverging lines iroin which are
discernible. The long, compound lateral curves have a considerably greater
degree of curvature than in the pedicle-valve, their posterior portion enclosing
a thickened area, which is continued into a peculiar low and thickened median
septum, bifurcating in the middle of the valve, the angle being occupied by
an intercalated ridge, which extends for twice the length of the branches of
the septum. This peculiar l)ifurcation maj- be due to the impression of tlie
anterior muscular scars at this point. The central scars are situated further back-
ward at the junction of the median septum with the posterior thickened area.

Type, Lingula suhspatulata, Meek and Worthen.

Observations. There can be no sufficient reason to doul)t the generic differ-
ence of shells possessing the above characters from described linguloids. The
condyles on the cardinal margin are themselves a dis-
tinctive feature. We have already directed attention
to Dr. King's observations upon this peculiarity in
Lingula ? Leswuri, Rouault,* a species which shows
evidences upon the cast, of two deep pits close to the
beak. In his opinion this character alone is sufficient
to exclude the species from the genus Lingula. Mr.
Davidson subsequently comparedf this species (L. Le- \v_^^^:,.-

sueuri) with the recent GloiUdia Palmeri, Dall, finding in '^"',::,,.^^S:;r:'""
both the development of amedian septum in the pedicle- aiioi- davimon.

valve and two lateral septa in the brachial valve. Just such septal features are
found in the pedicle-valve of B. subspatulala if we choose to consider the diverg-
ing umbonal furrows as homologous with the lateral septa in Glottidia ; but they
are not found in the brachial valve. The other internal markings of this species
are widely different from those of Lingula. The central muscular scars are

* vide supra. Annals and Mag-azine Natural Hisloi-y, July, 187S. p. Ui.
t Brachiopoda Budleigh-Salterton Pebblo-bed, p. 302.

64 PALAEONTOLOGY OF NEW YORK.

placed veiT far back, especially in the brachial valve, where the thickened area
against whicli they abut, and the semicircular lateral impressions bounding the
area, suggest the compound central muscular thickening and the curved lateral
scars seen in some species of Obolella. The long curved anterior furrows in
both valves at once suggest homology with the vascular trunks or pallial
sinuses in Lingula. No specimens of these shells, however distinctly the in-
terior markings may have been preserved, give any indication of branches from
either side of these furrows, and it may be well to bear in mind in determining
the relations of the genus, their similarity to the long laterals in Obolella.

On tlie l)asis of interior characters, Lingula subspatulata is the only species
known tliat can be safely referred to this genus. This form was described by
Meek and Worthen in 1868,* from the black shales (Genesee horizon) underly-'
ing the Goniatite limestone (Kinderhook) near Rockford, Indiana, and Union
county, Illinois. Professor A. WiNCHELLf has suggested the specific identity of
a form found in the black shales at Vanceburg, Kentucky, and elsewhere on both
sides of the Ohio river, included within the Waverly series, but this is evidently a
higher horizon than the Indiana and Illinois occurrence, and we surmise that the
Waverly form mentioned by Professor Winciiell will prove to be the L. Melie, Hall.
The same author also suggests the identity of L. subspatulata, Meek and Worthen,
with his L. membranacea, from the Burlington sandstones. The only figure we have
of this latter form is one given by Meek:]; in 1875, in which there are indications of
the high cardinal area and apophyses in the former species, though the quadrate
outline of L. membranacea gives it a specific impression distinct from that of L.
subspatulata. The Lingula paliformis, Hall, of the Hamilton shales of New York,
may also prove to belong to Barroisella, though the character of the cardinal
area and the internal markings as far as now known, do not serve to distinguish
it from LiNGULELLA. With Barroisella may be compared the Bohemian species
Lingula Davidsoni, Barrande,§ and L. insons, Barrande,|| from the Etage D.

* Geological Survey of Illinois, vol. iii, p. 437, pi. xiii, fig-. 1.
t Proceedings American Philosophical Society, vol. xii, j). 248.
J PaliEontology Ohio, vol. ii, pi. xiv, fig. 4.
§ Systome Silurien, vol. v. pi. 104, i\g. viii.
I Systfeme Silurien, vol. v, pi. lO.o, fig-, x.

BRACHIOPODA.

65

FIUS.

Fig.

JJngula Criei. Aiicr Davidson.
■lij. Inienial cast and inteiioi- of posterior poiiion of

pedicle-valve.
Inienial ca.st of pedicle-vnive. Natural size.

Genus TOM A SIN A* gen. nov.

Under the name, Lingula Criei, Mr. Davidson described, in 1881,f a linguloid
fossil from the Armorican gi-it of the Di-partement de la Sartlie, having a cardinal
area of such peculiar structure
as to render its separation from
the geims Lingula necessar}-.

"The pedicle -valve is very
slightly convex, its posterior
margin being notched. This
notch is divided into two parts
by a small triangular elevation,
leaving on each side a well de-
fined depression or little cavity. Aside from this slight elevation, the valve
presents a gentle longitudinal convexity, which extends a little in front of the
center of the valve, the lateral portions of the shell remaining almost Hat. The
opposite valve appears to have been somewhat more convex than that we have
described.

" This notch in the area for the passage of the pedicle is very remarkable,
and I have never before observed it in any of the numerous species of the genus
which I have studied. In the interior of this same valve, beneath the pedicle-
aperture, there are two small processes with a depression between them, and
the central muscular impressions are well defined, but I have been unable to
find any other impressions upon the internal casts which M. Guillier
has sent me."

The internal processes upon the cardinal margin are so large that they may
have served purposes of articulation to some extent. In this respect the fossil
shows structure similar to that seen in its associate in the same fixuna, Lingula 1
Lesueuri, Rouault.

* Out of regard for the memory of Mr. Davidson, to whom we are indebted for our knowledge of this
fossil, the above name is propesed.

f Bulletin de la Societe Geoloyique de France, p. 372. ISS! ; Note snr les Ling-ules du grfis aiTOOncain
de In Siuthe. jiar M. A. Gdilliek, avec descriptions et figures des esp6ces, pur M. Tii. D.widsun, pi. vii.

66 PALEONTOLOGY OF NEW YORK.

Genus OBOLELLA, Billings. 1861.

PLATE II, FIGS. 31-«.

1S-J7. Orbicidaf, Hall. Palreontolog-y N. Y., vol. i. p. 290, pi. Ixxix, figs. S a, b.

1S47. Avicida?, Hall. Palaioutdlogy N. Y., vol. i, p. 292, pi. Ixxx, figs. 3a, b.

18.')2. Oholus, OWHN. Geological Siirvey of Wisconsin, Iowa and Minnesota, pp. 501, 631. pi. 1 B.

1860. Lingular, Hall. Annual Report Geological Survey of Wisconsin,

IStil. OboUlla, BiLLixGS. Geology of Vermont, vol. ii, p. 94G.

1S62. Oholella, Billi.ngs. Geology of Canada; Paleozoic Fossils, vol. i, p. 7.

1862. Obolella, Meek and Hayden. Proceedings Acad. Nat. Sci. Phila., vol. xiii, p. 435.

1863. Obolella?, Hall. Sixteenth Rept. N. Y. State Cab. Neat. Hist., p. 133, pi. vi, figs. 17-21.
IS65. Obdlrlla, Mbek and Haydbn. Paleontology Upper Missouri, pp- 3, 4.

1866. Obolella, Davidsok. British Silurian Brachiopoda, p. 60.

1871. Dicellomus, Hall. Advance sheets Twenty-third Rept. N. Y. State Cab. Nat. Hist.

1871. OboliUa, Billings. Canadian Naturalist and Geologist;

1872. GholiMa, Billings. American Journal of Science, vol. iii, p. 355.

1873. OboUlla, Ford. American Journal of Science, vol. v, ji. 213.

1876. Obolella, Billing.s. American Journal of .Science, vol. xi, p. 176.

1877. Obolella?, Hall and Whitfield. King's Rept. FiXploration Fortieth Parallel, p. 205.

1880. Obolella, Whiti'IELD. Paleontology of the Black Hills, pp. 339-341.

1881. Obolella, Fokd. American Journal of Science, vol. xxi, p. 131.
1884. Obolella?, Walcott. Paleontology Eureka District, p. 67.

1886. Obolella, Walcott. Bulletin No. 30, U. S Geological Survey, ^ip. 109-119.
1889. Obolella, Walcott. Proc. U. S. National Museum, vol. xii, p. 36.

Diagnosis.* Shell iiKirticulated, ovate or siiborbicular, lenticular, smooth,
concentrically or radiately striated, sometimes reticulated by both radiate and
concentric strice. Ventral valve with solid beak and a small, more or less
distinctly grooved area. In the interior of the ventral valve there are two
elongated, sublinear or petaloid muiscular impressions, which extend forward
from near the cardinal scars, sometimes to points in front of the mid-length of
the shell. These are either straight or curved, parallel with each other or
diverging toward the front. Between these, at about the middle of the shell, is
a pair of small impressions, and close to the hinge-line a third pair, likewise
small, and often indistinct. There is also, at least in some species, a small pit
near the hinge-line, in which the groove of the area seems to terminate.

The dorsal valve has a small, nearly flat hinge-facet ; the minute beak is
slightly incurved over the edge of the area. Beneath the beak there is a small
subangular ridge, on each side of which there is a cardinal (?) scar. The elon-

* Derived from Mr. E. Billings' diagnosis in 1872 (loc. (At.) and the emended description of the type-
species, 0. chromatica, by the same author in 187R {loe. cit.).

BRACHIOPODA. 67

gate scars, which seem to correspond to the laterals of the ventral valve, are
here altogether in the upper hall" of the shell, diverging widely in their exten-
sion forward, and are generally very slightly impressed. In the cavity of the
valve there is a low, rounded median ridge, which extends from a point near
the hinge-line forward to a little below the mid-length of the valve. About
the middle of the shell there are two small .scars. These are usually striated
longitudinally, the median ridge passing between them. The area is coarsely
striated.

Type, Obolella chromaiica, Billings.

Obsekvations. Since the date of Mr. Billings' studies of Obolella,* much
valuable information in regard to the character of the interiors of these shells,
especially of the brachial valve, has been contributed by Mr. S. W. Ford, in
various papers in the American Journal of Science, and by Mr. CD. Walcott,
in Bulletin No. 30 of the United States Geological Survey. Mr. Billings
assumed three species as types of his genus: (1) 0. chromatica ; (2) the Avicula?
desquamata, Hall (=^ 0. crassa, Hall) from the limestones near Troy, N. Y. ;
(3) "A small species from the Potsdam sandstone of the St. Croix River," which
had been described by Professor Hall as Lingula? polita,\ and was subse-
quently! referred with some degree of doubt to the genus Obolella.

The original figures of O. chromatica, the first-
mentioned type-species, gave but a very imperfect
representation of the character of the interior of the
pedicle-valve, and showed only the two elongate oboteiia chromatica.

^ lie Anci- Billings.

lateral muscular scars. § Subsequently the figures fig. is. interior oi i.e.iicie-vaive.

, KIG. ■£>. Intoi-ior of brachi.il valve.

here copied, were published by Mr. Billings m tlie

American Journal of Science,|| giving the interiors of both valves, as far

as then known to him; previously, however, in -the same journal,ir he

* PaliEozoic Fossils, volTl86l7canadim^Nat^ralist, 1S72 ; Amer. Jour. Science, 1872 ; Idem, 1876, etc.

1 1860. Report Geologrical Survey Wisconsin.

t 1863. Sixteenth Report N. Y. State Cab. Nat. Hist.

§ Palaeozoic Fossils, vol. i, p. 7.

1 Vol. xi, 1876, p., 176.

f Vol. iii, 1872.

68 PALEONTOLOGY OF NEW YORK.

had given excellent figures, showing very completely the characters of the
pedicle-valves of 0. desquamata (=^ 0. crassa, Hall), and 0. gemma, Billings.
But in 1863,* the interiors of both valves of Oboklla? polita, Hall, had been
illustrated, and the figure given of the pedicle-valve (there termed " dorsal ? ")
represents the impressions almost precisely as we now know them to be in the
corresponding valve of 0. chromatica, 0. crassa, and others ; while those of the
opposite valve, usually less distinctly retained than in the pedicle-valve, show
the long, curved laterals and the central scar. (See further under discussion
of DiCELLOMUs.) In 1881, Mr. FoRof demonstrated the interior characters of
the l)rachial valve of 0. crassa, subsequently amplifying his observations some-
what in a figure published by Mr. Walcott in Bulletin No. 30, 1886. In this
work, Mr. Walcott also gives a figure of the interior of the same valve of
0. chromatica, demonstrating the complete harmony of its scars, both in
arrangement and development, with those of 0. crassa. The same author
gives, in addition, illustrations of the interiors of 0. gemma, and 0. Circe,
Billings.

The genus Obolella possesses, as far as known, a larger specific representation
than any other group of primordial brachiopods, but all species that have been
referred to the group are not congeneric. The true Obolella, as far as it is
accurately known, is not only confined to primordial faunas, but is believed to
be largely American in its representation. The forms referred by English
writers to the genus fail to show the characteristic generic features. Some
of them have already been assigned to other genera, e. g., 0. sagittalis, Salter,
to LiNNARSSOXiA, Walcott, to which genus probably belong 0. Belti, Davidson,
and 0. maculata. Hicks ; 0. Sabrincc, Callaway, will undoubtedly prove a repre-
sentative of a distinct genus, its relations to Acrotreta having been pointed out
by Mr. Walcott.

Certain of M. Barrande's species show internal features indicating their
close alliance to Obolella, e. g., Lingula Feistmanteli,X Obolus? complexus,^ Obolus

* Hall. Sixteenlh Kept. N. Y. Stjite Cab. Nat. Hist. {loc. cit.).

+ American Joui-nal of Science, voL xxi, \i. 131.

t Syat. Sil. Boheme, vol. v, jjl. 106, fig-, iv.

§ Syat. Sil. Boheme, pi. 95, tig. iii ; pi. Ill, tig. vi ; pi. 152, fig-, ii, 4.

BRACHIOPODA. 69

advena* These are all from the Etage D, and should they prove referaljle to
Obolella, will constitute the latest recorded appearance of the genus.

The American species which can safely be classed as Obolklla are the fol-
lowing : 0. chromatica, Billings, 0. crassa. Hall, 0. Circe Billings, 0. gemma,
Billings, and probably 0. polita,\ Hall.t Of other species referred to the genus
by American writers, it may be remarked :

O.? ambigua, Walcott,§ will probably prove referable to the genus Elkanma,
as suggested by the author of the genus, Mr. Ford.||

0. calata, 'Ro\\,^^= Lingulella calata {Orbicula c.alata, HallH).

0. cingulata, Billings, = Kutorgina cingulata.

0. desiderata, Billings,** is the type-species of Elkania.

O. ? discoidea, Hall and Whitfield ;ff generic character in doubt, as the interiors
are not known.

0. ? Ida, Billings,ii is imperfectly known.

0. ? misera, Billings,§§ is referred to the genus Linnarssonia, by G. F.
Matthew.IIII

0. nana, Meek and Hayden.TITI Mr. Walcott is disposed to consider this

* Sjst. Sil. Boheme, pi. 95, fig. iv.

t The L'mgula prima (Conrad's MS. description, first published by Hai.l, Pal. N. Y., vol. i, p. 3. 1847),
ffom the Potsdam quartzite at Ausable Chasm, N. Y., has been referred by Mr. Whitfield (Bull. American
Museum Nat. Hist., vol. i. No. .5, p. 142. 1884) to the s;enus Obolklla, .and is also identified by him with
the species 0. ? polita, Hall, from the yellow pulverulent sandstones at TrempHleau, Wisciinsin, so that,
should this identification hold good, the latter name will become a. synonym of the foi-mer. The identifica-
tion is, however, made solely on the basis of external similarities, and must I)e I'egarded as subject to such
modifications as the interior characters, whtm known, may require. These have not been satisfactorily
demonstrated in the New York specie.s but there are specimens before us which imlicate that its muscular
impressions are more nearly those of Lingdlella than of Obolblla. The Obolella nitida of Mr. S. W. Fokd,
also considered by Mr. Whitfield a synonym of the same species (op. cit.), appears, from an examination
of the type-specimens, to be a totally distinct fossil.

t Under the name Obolella Atlantica, Mr. Walcoti' has mentioned, without giving a detailed descniition,
an additional species fiom the Olenellus zone. Conception Bay, Newfoundlaml (Proceedings U. S. National
Mus., vol. xii, p. 3(3. 1889).

§ Palseontology Eureka District, p. G7, pi. i, figs. 2a-c. 1884.
J American Journal, vol. xxxi, p. 467. 1886.
^Paleontology N. Y., vol. i, p. 290, pi. Ixxix, fig. 9.
** Palseozoic Fossils, vol. i, p. 69. 1862.

tt Geographical and Geological Exploration Fortieth Paralh-1, ;. tinr.. i.l i. ti .rs. 1. 2. I'^ll.
tt Palaeozoic Fossils, vol. i, p. 71, figs. 63 a, b. 1862.
§§ Palaeozoic Fossils, vol. ii, p. 69. 1874.
11 lUusti'ations Fauna St. John Group, No. iii, p. 3'). 1885.
1[1[ Palaeontology Upper Missouri, p. 4, pi. i, figs. 3 a-d.

70 PALEONTOLOGY OF NEW YORK.

species as identical with O.pnlita, Hall * but specimens of both species, from the
original localities of each, show differences in the much less convexity of O.
nana, its more triangular outline, and its usually smaller size. Should these
differences prove constant, the species may be regarded as well defined.

0. niiida,¥ ovd.f Mr. Ford's specimens show a very tenuous phosphatic shell
which has not retained any trace of the internal characters.

0. pretiosa, Billings.J Interiors of the type unknown. Mr. Walcott suggests
their relationship to Acrothele ;§ but specimens which have been placed in our
hands by Sir William Dawson, from the Quebec group at Little Metis, and
which show no external differences from 0. pretiosa as described by Billings,
have iill the internal characters of the genus Linnarssonia.

0. transversa, Hartt, = Linnarssonia, Walcott.

Our discussion of the generic characters of Obolella must, therefore, be
limited to observations made upon the authentic species cited.

Primarily, a distinct cardinal area is developed in each valve. On the
pedicle-valve this feature is much the more conspicuous, and is crossed by a
pedicle-groove, which is not a slit cut through the area, but only a depression
on its surface. The brachial valve on the other hand shows only a broad
sinuate depression as seen in the figure of 0. gemma given on Plate II (fig. 43
[34 in error] ) ; in 0. crassa this valve has a somewhat triangular area with a
very slight ridge occupying a position correlative to the pedicle-groove of the
other valve. Mr. Ford's figure, given in Bulletin No. 30, United States
Geological Survey, || makes this feature much stronger than it actually appears
in the specimen from which the drawing was made. Though the same feature
is shown in Mr. Walcott's figure of the brachial valve of 0. chromatica^ it
remains to be determined whether or not it is a constant character in these
species.

* Bulletin No. 30, U. S. Geological Survey, p. 111.
t American Journal of Science, 1873, vol. v, p. 213.
\ PalsBozoic Fossils, vol. i, p. 68. 1862.
§ Bulletin No. 30, U. S. Geological Sni-vcy, y. 111.
I PI. X, fig. 1 a.
IT Bulletin No. 30, U. S. Geological Survey, pi. xi, lig. 1 h.

BRACHIOPODA. 71

The latter author also describes and figures* a brachial ,^iV

valve of 0. gemma IVoni Bic Harbor, below Quel^ec, in which
the cardinal area is quite narrow and boars a deep pedicle-
groove. It is possible that this feature may be subject to so
great variation within the limits of the same species as in-
dicated by Mr. Walcott's figure and our own; but this point
requires verification. ^^^J^l^ 1^:;:^;!;^™;'

In the pedicle-valve the groove on the urea is followed by a deep pedicle
muscular impression, which is flanked on either side by narrow, elongate cardi-
nals. The lateral scars begin near the pedicle-pit or scar and curve gently-
outward, and again inward near their distal extremities, extending two-thirds,
sometimes three-fourths the length of the shell. They are not always a simple
groove, but in 0. crassa each margin of the impression is more deeply sunken
than the rest, thus leaving a low ridge between them. In the post-median
region, the central scars are usually ill-defined but evidently compound, and
in 0. crassa are seen to consist of three subcircular scars, two outer and one
inner ; these are bordered on the anterior side by a series of thread-like ridges
and furrows. In 0. gemma the entire central scar is more deeply impressed,
and partakes of the tripartite character, the median portion being the most
prominently developed.

In the brachial valve, the laterals take their origin in the median region
of the shell, adjacent to, or in the central impressions, and curve outward.
An excellently preserved interior of this valve of 0. crassa shows a subrhom-
boidal central scar with straight sides and with the apex pointed posteriorly ;
the margins are more depressed than the center, but the impression is not
divided by a ridge into two scars, as represented in Mr. Ford's figure.f The
laterals branching from this scar are very broad and slightly curved. In other
species the central impression is usually indefinite in its details, as ui the pedi-
cle-valve, but shows a subdivision into outside and median scars

The cardinals in 0. crassa are well defined and, at their anterior extremities,

* Bulletin No. 30, U. S. Geological Survey, p. 117, pi. x. fig. 2d.
t Bulletin No. 30, U. S. Geological Survey, pi. x, fig. 1 d.

72 • PALEONTOLOGY OF NEW YORK.

merge into a pair of elongate submarginal scars, which may be termed the ex-
ternals. They appear to represent the terminal crescent scars in the Trimerel-
loids, but cannot, with propriety, be regarded as correlates of the great laterals
of the opposite valve (see Ford, Walcott, op. cit.).

The term Dicellomus was proposed in March, 1871, in a paper published in
advance of the Twenty-third Annual Report on the Condition of the State
Cabinet of Natural History, for the species which had been previously described
as Obolella ? polita* the Lingula ? polita, Hall, 1860,f and the Obolus Apollinus,
Owen, 1852.T This species was also the third type under Billings' diagnosis
of Obolella. Dicellomus was also made to include, as a second type, the Orbi-
cula ? crassa, Hall, 1847, but this latter species proves to be congeneric with
Obolella chromatica. The interior characters of the former species are still some-
what imperfectly known, the original illustrations of them which are repro-
duced upon Plate II (figs. 40, 41), being somewhat constructive, but the pedicle-
valve, while showing an unusually strong cardinal area, has the pedicle-groove,
the cardinal, lateral and central muscular scars, quite as in typical Obolellas ; in
the brachial valve the apparent correspondence of the scars with those of
Obolella chromatica and 0. crassa is less marked. Upon this plate are given ad-
ditional figures of the interior of this species, the pedicle-valve (fig. .38) showing
two very strong centrals, bounded, on the posterior margin, by a thickened,
triangular area, extensions from which pass between and around the outer sides
of the scars. The outer posterior margins of this area bear the impressions of
the cardinal or external muscles, while below the position of the pedicle-groove
(the cardinal area is not retained on this specimen) lies a pedicle-scar. The
whole appearance of this interior is strongly suggestive of that in Obolus, but
may not prove inconsistent with the character of Obolella. In the brachial
valve, the impressions are more distinctly obolelloid, the long, curved laterals
taking their origin at the compound central scar. The development of the in-
terior details of the shells of this species is a matter of much difficulty, as the

* Sixteenth Rupt. N Y. Slatif CiiL. Nat. Hist., p. 133. 18G3.

t Annual Report Geological Survey Wisconsin, p. 24.

I Report Geological Survey Wisconsin, Iowa and Minnesota.

BRACHIOPODA. 73

substance of the shell is frialtle iind chalky, and the sandstone so loose-grained
that internal impressions are not distinctly retained. Should future study of
the species prove it generically distinct from 0. chromatica, it will be necessary
to accord recognition to the term Dkellomus, which, however, may be held in
abeyance until that time. There is a noticeable similarity in the interior of the
pedicle-valve of O. politn as shown in fig. 38, to the illustration given by Vol-
BORTH of the interior of the corresponding valve in the species Schmidtin cclata*
in which all the details represented are the two strong cen-
tral scars abutting against a thickened posterior area. The <^^'.!'^!^^'!|i,\
correspondence in internal markings does not appear to ex-
tend to the brachiid valves. (See discussion of the genus,
ScHMiuTiA ) Attention may also be directed to the Obolus ?

Kio. .31. Obobisl comjilcxns

complexus of B.\RRANi>i;,f from the Etage D, apparently a After hauuvnuk.
genuine Obolella, in a later fauna than has been elsewhere observed.

Genus LEPTOBOLUS, Hall. 1871.

I'LATK III, FIUS. 1-10.

1S71. Leptoholas, Hall. Desciiptioiis New Species Fossils, p. 3 ; Advance sheets Twenty-fourth Rept.

N. Y. State Mas. Nat. Hist.
1872. Leptoholus, Hall. Twenty-ftmrth Rept. N. Y. State Mus. Nat. Hist., p. 226, pL vii, fig-s. 17-20.
1875. Leptobolus, Hall and Wuitimeld. Paheontolofry of Ohio, voL ii, p. CP, pi. i, fig?. 10, 11.

Diagnosis " Shell semiphosphatic, fragile, minute, more or less elliptical,
ovate or subcircular, with moderately (or sometimes more extremely) convex
valves, which are concentrically marked on the exterior surface. Ventral
valve with a distinct pedicle-groove; interior with an elevated subquadrate
muscular area. Dorsal valve a little thickened on the cardinal margin, with
slightly elevated, trifid muscular impressions," Hall {loc. cit.).

Type, Leptobolus lepis, Hall, Hudson group, loc. cit., p. 226, pi. vii, figs.
19, 20.
L. occidens, Hall, Hudson group, loc. cit., p. 227, pi. vii, fig. 18.
L. insignis. Hall, Utica slate, loc. cit., p. 227, pi. vii, fig. 17.

* Verhandl. dei- russ.-kais. Mineral. Gesellst*. zu St. Petei-sb., 2te Sei-., Bd. iv. taf. xvii, fig. 1. 18B8.
t Systfeme Siliuien Boheme, vol. v, pi. 152, fig-, ii, 4 ; also, pi. 9.->, fif,'. iii ; pi. HI, «■,'. vi ; pi. 113, fif,'. v.

74 PALEONTOLOGY OF NEW YORK.

Observations. There is a noticeable variation in tlie internal characters of
the species referred to this genus, hut it does not appear to be of an essential
nature, or of a greater degree tlian might be expected in different species ;
indeed this variation is strikingly apparent in different individuals of the same
species.

Of the interiors of the three known species of Leptobolus, that of L. occidens
is not yet satisfiictorily known, but those of both the other species aie of not
uncommon occurrence. L. lepis is found in the Utica slate of New York, at
Holland Patent, and elsewhere, having been washed by thousands into the rill-
marks or depressions in the sediment, but upon cleaving the rock the shells are
exposed with their interiors usually attached to the matrix, making it necessary
to remove the scale-like shell in order to ascertain the internal characters. In
the gray, muddy shale of the lower part of the Hudson group of Ohio
(Utica horizon), the same species has accumulated in great nnmbers, and
by breaking the rock the interiors are usually exposed ; the specimens ax'e,
therefore, in a nuich more favorable condition for study. Leptobolus insignis,
readily distinguished from L. lepis by the radiating strise on its internal surface,
is found in nmch the same condition of preservation, but in the more compact
layers of the Cincinnati or Hudson group. It will be understood that shells
washed about as these have been, may often have lost the clear definition of
their delicate interior impressions, but examples are not infrequent which
retain with great sharpness all the internal details.

Tlie interior of the pedicle-valve shows a notably large cardinal area, which
is sharply grooved. Beneath this area, in the bottom of the valve, is a broad
depression extending nearly across the shell, and divided by a low median
ridge, which bifurcates at its extremity, leaving between its branches a small
central muscular impression. This latter feature is more clearly developed in
L. lepis than in L. insignis, but in the latter species the entire depression is
much more clearly defined, its ante-lateral margins being produced slightly for-
ward. This impression is bounded on its sides by a crescentic muscular fulcrum,
which extends, parallel with the margins, to the anterior portion of the shell. At
a point back of tlieir centers, each gives out a transverse branch extending in-

BRACHIOPODA. 75

ward and backward. These callosities arc strongly suggestive of the appear-
ance produced by the combined lateral and central scars in Obolella chromatica
and 0. crassa, and it is probable that they represent the same features, in which
case the posterior depressed area is to be regarded as the progressive track of
the centrals, its anterior margin advancing with age.

The position of the valve lying between the anterior liorns of the lateral
semilunes is also deepiv depressed, but its surface shows no markings. The
specimens of L. lep/s from the Cincinnati rocks appear not to have retained
these lateral callosities, but they are faintly developed in tiie New York exam-
ples of the same species.

In the brachial valve, the cardinal area has about the same degree of devel-
opment as in Obolella, and is also distinctly grooved. The muscular scars in
this valve are poorly defined, but their limits are probably indicated in part by
the septa, which in L. lepis are three in number; one in the axial line larger
than the rest, and one on either side. All these ridges appear to be bifurcated
at their anterior extremities, in the axial ridge the faint duplication beginning
at about the center. In the Utica slate specimens of/., lepis the lateral ridges,
in the only satisfactory example observed, appear to be curved inward toward
their extremities, as they also are in L. insignis where they attain a very con-
spicuous development, uniting with each other in front and being separated
from the margin of the shell only i)y a low furrow. These ridges may be re-
garded as the curved fulcra of the lateral muscles.

The features seen in Leptobolus indicate its clo.se alliance to Obolell.v, luit
are at the same time so diverse from those of Obolella chromatica that the forms
can not be regarded as congeneric.

Genus ELK AN I A, Ford. 1886.

PLATE in, FIGS. 15-19.
1862 Obolella, Billings. Palaozoic Fossils, vol. i, p. 69, tig. G2 ii, !>.
18S4. Obolella?, Walcott. Palffiontoloffy Eureka District, p. 67, pi. i, tig-. 2.
1886. BiUingsia, Fobd. American Journal of Science, vol. xxxi, p. 466.
1886. Elkania, Fokd. American Journal of Science, vol. xxxii, p. 32").

This genus has been established by Mr. S. W. Ford upon the late Mr. Billings'
species, Obolella desiderata, from the Graptolite shales at Pointe Levis. We have

76 PALEONTOLOGY OF NEW YORK.

had before us for the study of this form, Mr. Billings' original specimens, which
give very clearlj- tlie interior characters of both valves. These were lucidly
described by the author, although he was not disposed to regard them as gener-
ically distinct from Obolella chromaUca. Tliis description, given upon page 70 of
the work cited, is in the following terms :

'• Fi'om some nearly perfect casts of the interior, the following characters
can be made out. In one of the valves (supposed to be the ventral) a strong
rounded groove commences just beneath the beak, and runs along the median
line to about the center of the shell. On each side of the principal groove is
a large ovate nmscular impression, extending from near the mid-length of the
shell a little more than half-way to the beak. These impressions are bounded
and distinctly defined at their lower extremities by the two small, diverging
grooves above mentioned. Their outer and upper margins are distinctly de-
fined. In the rostral part of the shell there are two small grooves which take
their origin close to the beak, one on each side, and run toward the front,
diverging to the outside of the upper part of the two large muscular impres-
sions. The characters of the interior of the dorsal valve are somewhat similar
to those of the ventral valve, but the median groove is shorter, and there is a
thickening of the shell just below the beak, which presents the appearance of
a false area inside the cavity of the umbo. It is probable that the two small
grooves above mentioned are connected with the small muscular impressions,
which, in 0. chromaUca, are distinctly seen outside of the two larger. The
condition of our specimens, however, is such that this point must remain open
for fnrtlier investigation."

In subsequently proposing to designate this shell by the term Billingsia (a
name afterwards changed to Elkania as the former proved to have been already
in use), Mr. Fouu gave a much enlarged and somewhat schematic figure of the
pedicle-valve (which we are disposed to believe emphasizes rather too strongly
the internal characters), and accompanies it with the following diagnosis of the
generic characters {loc cit., page 467) :

" Shell thin, calcareous, inarticulate, longitudinally ovate or subcircular, con-
vex. Ventral valve with a solid beak and a minute area, which, in the typical
species, is grooved for the passage of the pedicle as in Obolella. Muscular
impressions in the ventral valve, six; one pair situated close to the cardinal

BRACinOPODA. 77

edge, one on either side of tlie niedi;in line ; a second, smaller pair, placed
directly beloAV the former ; and ontside of the latter a third pair of large elon-
gate or subreniform impressions, converging forward. Beneath the rostrnm
there is a prominent spoon-shaped pit or chamljer separating the above men-
tioned impressions, with which the groove of the area is conliiient. In the
dorsal valve there are also three pairs of impressions disposed in nearly the
same manner with those of the ventral valve. The dorsal valve is not known
to possess an area. The surface is concentrically striated."

From the specimens before us, the shell-sul)stance ol' Elkania desiderata
appears to be largely corneous and distinctly laminated. Several examples in
which the external layer of the shell has been exfoliated are covered with
conspicuous papillae which may indicate a punctate structure in the iinier layers,
a feature not hitherto noticed in Oboi.ella or its immediate allies. We have
not been able to discover the minute cardinal area mentioned by Fouo, although
this feature should have been retained on tlie specimens examined, if it was
distinctly developed. On tlie contrary, there appears to be, just within the
marginal apex of what is above considered as the ventral valve, a broad,
subtriangular depression, into which the central "spoon-shaped" cavity merges.
This central cavity, in five examples of the interior of this valve, has a more
or less distinct development, its definition being sometimes obscured by the
flattening of the shell. When best preserved, it shows two narrow furrows
diverging from its anterior extremity, which continue a short distance and be-
come abruptly extinct. These two furrows separate the anterior extremities
of the broad lateral muscular scars, which are quite indistinctly limited, while
the smaller impressions, termed by Fokd the " centrals", are faint, but dis-
tinctly seen in favorable light. The two small grooves in the rostral portion
of the shell, diverging from the beak, were regarded by Ford as constituting
the " cardinal" scars. These are, however, very elongate, and pass from near
the pedicle-groove outward, skirting the posterior portion of the lateral impres-
sions, and appear to terminate in distinct, subcircular scars situated between the
laterals and the lateral margins of the valve. Should this character prove of
permanent value, it will be of significance as aiTording an analogy between
Elkania, Obolus and the Trimerellids.

78 PALEONTOLOGY OF NEW YORK.

The opposite viilve sliows the very peculiar feature mentioned by Mr.
Billings, a thickened area in the umbonal region presenting the appearance of
a false cardinal area inside the cavity of the umbo, a character which is sug-
o-estive of that in Lingulasma, but evidently of different function. This area
is tripartite, bearing a deep, narrow central and two broader lateral grooves ;
about its anterior margin lie two broad scars of the same character as the
laterals of the other valve. There are also seen the diverging furrows, which,
starting at the marginal apex, pass over the edge of the thickened area, and
are most deeply impressed at their anterior extremities.

To homologize the muscular features seen in Elkania with those of Obolella
or any allied genus, is a difficult matter. Mr. Ford was disposed to regard the
central depression of the pedicle-valve as an extravagant development of the
pedicle-pit seen in 0. crassa and 0. chromaUca. This appears very plausible,
but complicates the correspondence of the other scars ; and, moreover, as the
internal .'^cars of the opposite valves do not essentially differ in their number
and arrangement, it would compel the assumption of a pedicle-pit in the
brachial valve. Mr. Foru has suggested that Walcott's species, Obolella ? am-
bigua* i'rom the " Pogonip group " of Nevada, is congeneric with E. desiderata.
Mr. Walcott's figures, 2 a, 2e, of the interior of the pedicle-valve, indicate the
unquestionable correctness of this reference.

Genus PATERULA, Barrande. 1879.

PLATE IV K, FIG. 1.

1S79. Paterttla, BABRiNDii. Rysteme Sihiiien du Centre do la Boheme, voL v. p. 110, pi. 95, fig.'!, i,

1-3 ; 1)1. 15-J, figs, i, 1-9.
1884. Paterula, Davidson. General Summary to Bi'itish Fossil Bi-aehioiKida, p. 391.

Diagnosis. "Les deux valves, circulaires ou faiblement ovalaires, ne pre-
sentent qu'un bombement tres pen prononcr vers I'exterieur. L'espace interne
devait done t'tre tres exigu.

" Ces deux valves se rencontrent habituellement isolees. Cependant, nous
figurons PI. 152, deux specimens de valves juxtaposees, qui paraissent avoir
appartenu a un meme individu. Nous pouvons ainsi constater, qu'il n'existe

* Palaeontology Eureka District, }>. 67, pi. i, fig. 2.

jl

BRACHIOPODA. 79

aucune fissure, sur la surface ni de I'une, ni de rautre valve. Ce fossile n'est
done pas une Discina. Mais nous ol)servons, an contraire, la trace d'une per-
foration sur le bord. Elle est indiqui-e par une petite cylindre de la roche, qui
la injectee et qui fait saillie sur le contour." Barrande, loc. cit.
Type, Paterula Bohemica, Barrande. Etage D.

The position of this genus, as far as it rests ui)on the character of tlie pedicle-
aperture, appears to be near that of Scuizobolus, while the narrow internal
septa diverging I'roin the beak suggest relationship to
Leptobolus. The nature of the shells is not well under-
stood, but it is evident, from the description and figures ^ /
given by the author, that it is allied to those forms in
which the pedicle-passage is in the first stages of its tran- f'°*-- rutuuu Luhemica.

r r n o After Uaruande.

sition from the interraarginal obolelloid condition, to the supramarginal phase
developed in Siphonotreta, etc.

In the "General Summary the British Fossil Brachiopoda" (p. 3'Jl), Mr.
Davidson has referred to this genus his species Discina ? Baldetchensis, a form
occurring in great numbers in the Llandeilo and Upper Caradoc, and though
like the Bohemian species in the character of its broad marginal rim, no evi-
dence is afforded of the pedicle or internal characters. We liave received from
Mr. H. M. Ami the only American specimens which we should feel disposed to
refer to this genus. An enlarged figure of a gutta-percha impression taken
from the best of these, is given on Plate IV k, fig. 1, and sliows the conspicuous
rim, the pedicle-notch, and the radiating muscular impressions taking their
origin about an intramarginal callosity. This shell is from a black limestone
in the city of Quebec, currently referred to the age of the Quebec group.

80

PALAEONTOLOGY OF NEW YORK.

A NUMBER OF GENERA having more or k'ss close relationship to Obolella. have
been described by European writers, but are not at present known to have
representatives in American faunas. Such are Obolus, Monoboltna, Spondy-
LOBOLUS, AcRiTis, ScHMiDTiA, MiCKwiTziA and Neobolus. The original specimens
of these genera are mainly from primordial faunas, but they are to a great
degree imperfectly known, the figures and descriptions given by various authors
not always serving the requirements of the present status in the investigation
of these fossils. Much has yet to be learned in regard to the internal charac-
ters of most of them before their generic position can be established.

OBOLUS, EicHWALu. 1829.

1S29. Oholus, EicinvALD. Zoologia spetnali!?. vol. i, p. 274.

1830. Vnrjula, P.\nder. Beitr. znr Geogn. des Russisch. Reiches., p. r)5.

1840. Ovthii, Von Buch. Beitr. zur Bestimmungr fler Gebirgsform. Russlands.

1847. Aulonotreta, Kdtorg.\ (partim). Uebei- ilie Siphonotretsea;, p, 27S.

1848. XJnyulUes, Bronn. Index Palsontologicus, vol. iii, p. 1342.

1R71. VvsMtes. Qiiknstedt. Petrifactenk. Deiitschl. Brachiopoden, ji. 671.

Type, Obolus Apollinis, Eichwald. Unguliten-schichten.

This is the best known and most thoroughly studied of all the genera above
named. Externally the shells are much like those of Obolella, but are
generally larger and somewhat flatter. The
valves are unarticulated, both having broad,
grooved cardinal areas, though the gi-oove on
the brachial valve is sometimes obsolescent.
The interior oi' the pedicle-valve* shows a
pair of well-defined cardinal or posterior
adductor impressions, just behind the cardinal area and separated by a more or
less developed median septum extending to about the center of the valve.
The "laterals" are well developed and occupy a position not equivalent to the

* KuTORG.A and David.so.v (Inti'od. Brit. Foss. Bi-ach., pi. x, fifjs. 280-28ri) have not agreed in the determ-
ination of the valves of Obolus. Of Kutohga's lif^-ures of Aahmotrcta poHta (= Oholus Apollinis), those
lettered 10 &, h', c and d (op. cit-, pi. vii), are considered by the author as interiors of the dorsal (bi'achial)
valve, and fifjure /■, that of the ventral (pedicle-) valve. Davidson considei'ed, and with excellent reason,
tigs. 10 fc and b' as dor.'sal and o, d and e an ventral valves.

Obolus Apollinis.
Kiu. 33. rediclevahe. Al'ler DAVIDSON.
KiG. 34. Briiclnal valve. After Kutorga.

BRACHIOPODA. 81

impressions in Oboli^lla which have been designated by this term, but more
nearly to that of the terminal scars oF the crescent in Dinobolcs. The median
area of the valve on each side of the septum is much thickened, and at its
anterior edge lie the conspicuous central scars. hi the brachial valve the
cardinal and "lateral" (external or terminal) impressions are developed as in
the opposite valve, and in the central region is a pair of curved impressions
suggestive of, and probably corresponding to the elongate laterals in Obolklla.
These enclose an indistinct central scar.

The affinities of Obolus with the linguloids are somewhat remote and sicneral,
but are seen in the character of the cardinal area and the disposition of the
central muscular scars in the pedicle-valve. The strongly thickened median
area of the same valve, which is given prominence by the excavated central
scars, is suggestive of a rudimentary platform such as is found with greater
development in Lingulops, Lingulasma and the Trimerellids. This, however,
may be an homology only, as the nmscular scars in Obolus are not situated
upon, but at the anterior margin of this area. The external muscular impres-
sions with the ridge proceeding from them backward, toward the umbo, suggest
the crescent in Dinobolus, and are the equivalents of the terminal crescent
scars in that genus and the externals in Obolella, while the curved laterals in
the brachial valve show, as just noticed, the near relationship to the latter
genus.

A species from the St. John group, at Caton's Island, King's county. New
Brunswick, has been referred to this genus by Mr. G. F. Matthew,* Ijut we
have, as yet, no knowledge of its interior characters, and the reference requires
verification. The exterior of both valves of this shell is ornamented in the
umbonal regions by a reticulated punctation which is apparently superficial.
This becomes obsolete with tlie later growth of tli" <hell. (See Plate IV k,
fig- 22.)

* 0. pulckei; Matthew. Canadian Record of Science. .T.uin nv lsS9, ]). 306.

PALAEONTOLOGY OF NEW YORK.

Genus AULONOTRETA, Kutorga. 1848.

1848. Aulonotreta, Kctoroa. Debei- die Siphonof letaefe : Verhamll. der Russ.-kais. Mineral. Gesellsch.

zu St. Petersb. Jalirg. 1847, p. 278, pi. vii, figs. 10, 11.
1869. Acrltix, Volbokth. Ueber Schmidtia, iind Acritis, idem., 2te Sei'. Bd. iv, p. 217. pi. xvii, figs. 7-9.

The name Aulonotreta was proposed by Kutorga to take the place of
Obolus, Eichwald, as he deemed the latter an inappropriate name. The first type-
species under the description is A. polita, Kutorga, which "umfasst folgende, von
Professor Eichwald, aufgestellte Arten : Obolus ApolUnis, 0. Siluricus und ingricus,
deren untersclieidende Merkmale weder mit Worten, noch mit Zeichnungen
gegeben werden konnen."* As 0. ApoUinis is, however, generally recognized
as a well-defined species, Kutorga's first type and his genus, as far as it rests
on this type, became synonyms for Obolus. The second type, Aulonotreta sculpta,
Kutorga, is a synonym for the Obolus
antiquissimus, Eichwald,| and this species ^^ _ -N^

was taken by Volborth as the type of \ ^

his genus Acrh is.t The species is very \ ' ^ ^ f
imperfectly known. Volborth's figures \-- ^-^^ \j:

indicate a close agreement with Obolus

•x c Till i. c Acritis antiquissima.

in general lorm, and the characters ot ^^3,. v\,lboeth.

At T 1 rill • 1 i_ • Fig. 35. Interior ol" pedicle-valve.

the cardinal area. Ihe incomplete m- k.g.^w. i.uenor of irachiai vaue.

teriors figured show in the pedicle-valve, a broad, subquadrate median scar,
crossed on its posterior portion by a transverse band connecting what appear
to be cardinal scars. In the lirachial valve are two subcircular scars in the
median region just within the posterior margin. In the event of this form
proving distinct iVom Obolus, the laws of priority require that it shall bear
the name Aulonotreta, for which Acritis will then be a synonym.

* Pp. 281, 282.

t Ui-welt RiissL, 1843, p. 142, pi. iv, fig. 1 a, b, c.

X Lov. cit.

BRACHIOPODA. 83

Genus S C H M I D T I A , Volbortii. 186!).

1SG9. Sekmidtia, Volbortii. Ueber Schmidtiii „,id Acitis: Veiha.i.U. ,lei- Kiiss.-kiiis. Mineral. Gesell-

.sch. zii St. Petei-sb. 2te Ser. B,i. iv, p. 213, pi. xvii, tigs. 1-6.

Type, S. celata. Unguliten-schichten.

The shells of this genus have the form and external characters of Leotobolus,
Hall. TlK'pedicle-valve has a broad grooved
area, and in the middle of the valve are
two rather deep depressions separated bv
an elevated ridge, and having abrupt '|-. i

posterior margins, but with their anterior IV
edges illy defined. These features may be •;

compared with those seen on the interior .s.hmidua ca:iui„

of Oboklla polita, Hall (see plate ii, fig. 38). k.o.st. in?criorTpe"dicio.vaivc.

1„ ii „„ ;. 1 • T • 1 Fio. 3S. Interior of brachial valve,

n tlie opposite valve is a median ridge,

with a rather more sharply defined pair of elliptical depressions. iMr. Dall

observes* that the name Sch.mihtia was preoccupied in 1863 for a genus of

PoBIFEBA

Genus MONOBOLINA, Salter. 1865.

PLATE IV K, FIGS. 2, :l.

1865.. Monvholina, Salter. Mem. Geol. Survey Gifat iJritain, vol. iii, p. 334, pi. xi b, fiffs. 10, 10a.

1866. Oholellaf, Damdsok. British Silurian Bnichiopotla, p. 61, pi. iv, figi^, 20-27.

1871. Obolusf, Davidson. British Siluri.an Brachioiioda, Appen<lix, p. 341, pi. 1, fig-s. 23, 24.

1SS4. Oboliis, Davidson. British Silurian Bi-achiopoda. Gt^ueral Suniniai'V, p. 291.

" Section Monobolina, muscular scars united closeh- along the central line."
Salter {loc. cit.).

Type, Lingula plumbea, Salter. 1859. Lower Llandeilo.

The later figures given by Mr. Davidson of the interior of the type-species
show that the peculiar concentration of the muscular impressions as indicated
by Mr. Salter, is strikingly different from anything seen in Obolus, Obolella,

* Bull. U. S. Nat. Mus., No. 8, p. 62.

84 PALEONTOLOGY OF NEW YORK.

or the allied genera. Though Mr. Davidson, in all his citations of the species,
wa.s in doubt as to its generic character, he did not manifest an inclination
to adopt Mr. Salter's name; but from our present knowledge it seems
that the term Monobolina must be accorded recognition. Externally the
valves are covered with strong radiating striae, as in the brachial valve of
schizocrania.

Genus NEOBOLUS, Waagen. 1885.

18S5. Neobolus, WAAnRV. Memoirs fii-ol. Sni'v. India: Salt-Range Fossils, pt. i, vol. iv, fas. .^, p. 7.'56.

Types, Neobolus Warthi, Waagen, loc. cit., p. 75H, pi. 84, figs. 3-8.
N. Wynnii, Waagen, loc. cit., p. 759, pi. 85, figs. 1, 2.

This peculiar genus from the primordial beds* of the Salt Range of India,
presents some important deviations from the oboloid type of structure.

In general form and outline the shell is
oboloid with a somewhat transverse pos-
terior margin, which is slightly thickened, ['(■■■^ ^J>?
and in the pedicle-valve is traversed by a
broad, cross-striated pedicle-groove. The
cardinal muscular scars lie close upon this Afttr^WiToEN*

groove ; the central scars are faint, and in l\l !:; i!!:::;::: :[ S^lti^e.

the figure indistinctly defined, but are seen to abut against " a short thickened
ridge or knob " in the middle of the shell. Most striking are the broad mar-
ginal scars occurring on both valves, and wliich appear to represent the external
scars in Obolus, and the cre.scent in Dinobolus and its allies. In the brachial
valve a strong lougitudinally grooved callosity lies- just within the cardinal
margin, and this is more or less distinctly continued into a median septum.
The arrangement of the muscular scars other than those referred to, is not
fully understood.

* See remarks on pag-e 29.

BRACHIOPODA. 85

Genus SPONDYLOBOLUS, McCoy. 1852.

1552. SpondyloboliW!, McCoy. Aimals iiiul Jliig-azine Natural liistoi-y, vol. viii, p. 407.

1553. Spo7ulijluboliis, Davidso.v. lutiod. Biit. l''i).s.s. BiachiopoJa, p. 125; pi. ix, Kgs. 2-11-243.
IS55. Spondi/loboltui, McCoy. Bi-itish Palreozoic Fossils, p. 2.')5, pi. 1 n, tigi*. 4, 5.

Types, Crania Sedgwicki, Le\vi.s, C. craniohris, McCoy. Lower Llandeilo.

(The former .specie.s is not considered a Brachiopod by Mr. D.widson; vide
Silurian Bracliiopoda, p. 83, pi. viii, fig. 25.)

Very little is known of this genus except from the original description given
by McCoy, and the figures subsequently produced in the " British Paltoozoic
Fossils, p. 255, pi. In, figs. 4, 5. Mr. D.widson, from the first, expressed his
doubt of its generic value, but he has reproduced the original figures in both
the places cited. In the latter* he promises a further reference and explana-
tion of the fossil. We have not, however, been able to find anything of later
date, further than a casual mention of the name,! ^^^^ even the species does
not appear in any of his various lists and indexes.

McCoy's diagnosis of the genus is as follows :

" Subcircular, slightly narrowed towards the indis- /•"

tinct, short hinge-line, nearly equivalve, flattened. ^ \4|^

Small valve with a slightly excentric apex ; beneath «.-j^

which, on the interior, the substance of the valve is y^ti^
thickened into a wide, undefined boss. Opposite valve fio. 4i. spondyMoius cranwiana
slightly longer, from the apex being perfectly mar-
ginal and slightly produced, channeled by a narrow, triangular groove below,
the anterior end of which is flanked by two very prominent thick, conical,
shelly bosses, representing hinge-teeth ; substance of the valve thick, testace-
ous, not glossy, minutely fibrous, but not distinctly punctated under a lens of
moderate power, except by the ends of these fibres."

With our imperfect knowledge of this fossil, little can be said further than
to suggest its general obolelloid appearance, and the possibility that its cardinal
bosses may indicate a similar relation between it and Obolell.\ as is found to
exist between the species of the genus Barroisella and the true Lingulas.

* Expl. pl. viii, figs. 26, 27.

t General Sumniaiy, 1884. p. 352.

86 PALEONTOLOGY OF NEW YORK.

Genus MICKWITZTA, Schmidt. 1888.

1888. Mickicitzia, Schmidt. Ue.ber eine neueiideckte untoi-cambrische Fauna in Estland ; Mem. de

I'acad. imp. de.s Sciences de St. Petersbonr^, vii Sei-., tome xxxvi, No.
2, p. 24.

Diagnosis. Shells large, thick, unequivalve. Dorsal valve flat, circular ;
ventral valve oval, convex, produced
into an acute apex, beneath which lies
a triangular, more or less distinctly
developed cardinal area. Valves ';, W

not (?) articulated. Shell-substance Michu.-iuia mcai/era.

composed of thin coarsely punctate ^,^^ ^.^ Pe,Ucle-v.^lv'e'"FroTIntenor of same valve.

layers alternating with prismatic fig. 44. Extend- or brachial vaive.

laminis which are traversed by scattered vertical canals. Surface covered witli
radiating striae. Shell composed of calcic phosphate.
Type, M. monilifera, Linnarsson.

This name has been proposed by Dr. Schmidt for a shell which had been
described by Linnarsson in 1869,* from the Eophyton sandstone, the oldest
fossil-bearing formation of Sweden, and referred at that time to the genus
LiNGULA (?), ; subsequently by the same author in 1871,f to Obolus (?). More
abundant material found near Reval has shown various features which have led
to its establishment as a separate genus. The shell has the general appearance
of Obolus, and its relationship to this genus is shown in the external charac-
ters, and the grooved cardinal area. Unfortunately none of Dr. Schmidt's
specimens give a satisfactory indication of the internal characters, so that the
generic value of the species must still remain in great doubt. A remarkable
feature is shown in a single figure of the interior of the smaller valve, viz , a
single large tooth-like process, situated centrally behind the beak, and bent at
a sharp angle backward into what would have been the umbonal region of the
opposite valve.| Dr. Schmidt is not convinced that this is to be regarded as a

»6fver. af K. Vetensk. Akad. Forhandl. p. 344, t. vii, figs. 1, 2.

t Kongl. Svenska Vetensk. Akad. haiidling'ar, Bnd. 9, No. 7, ]). 9, pi. i, iig.s. 2, 3.

J SCH.MIDT, pi. ii, fig. 16.

BRACHIOPODA. 87

permanent feature of the species and genus (p. 22), it having been observed in
but a single instance ; but should more complete material establish its persist-
ence it would serve not only as a feature of generic distinction, but would
remove this form far from the Oboloids (cf. Crania ? Sedgwicki, Lewis : David-
son, British Silurian Brachiopoda, p. 83, pi. viii, iig. 25, which is believed not
to be a brachiopod).

SCHIZOBOLUS, Ulricii. 1886.

PLATE lU, FIGS. 11-14.

1862. Discinn, Hall. Sixteenth Rept. N. Y. St;ite Cab. Nat. Hist., p. 28.

■ 1867. Disciiia, Hall. Palaeontology of N. Y., vol. iv, p. 23.

1873. Trematis, Hall. Twenty -third Rept. N. Y. State Miis. Nat Hist., pi. xiii, fig-. 20.

18815. SiMzobolus, Ulrich. Contributions to American Palffiontolog-y, vol. i, p. 2a, pi. iii, ligs. 3 a-d.

Diagnosis. " Shell oval, depressed-conve.x, slightly inequivalved ; valves in-
articulate ; structure calcareo-corneous. CardintU margin somewhat thickened.

" Ventral valve with the apex at the terminus of a rather deep notch in the
posterior margin ; interior of the valve with two pairs of adductors, separated
by a faint median ridge or septum wliich traverses the valve from the posterior
margin, where it is bifurcated, to a point about two-thirds the length of the
valve from the anterior margin. The posterior adductors are very faint.

" Dorsal valve with the posterior margin straightened, the apex subterminal
and but little elevated ; interior of valve with a slender median septum which
separates two pairs of faintly impressed muscular scars ; the posterior pair
large, oval and situated just in front of the cardinal margin, the anterior pair
are less distinct, smaller, of triangular shape, narrowest in front, and situated
near the anterior end of the mesial septum.

" Very faint impressions of hiteral muscles were observed near the margin
of both valves." (Ulrich, loc. cit.)

Type, Discina truncata, Hall.

The type-.species of Mr. Ulrich's genus was described first in 1862, and sub-
sequently, with illustration, in 1867 {loc. ciL), as Discina truncata, from the
Genesee slate of Seneca county, New York. In both these places attention
was called to the fact that the muscular impressions, as far as observable, dif-
fered from those of Discina. Subsequently the species was referred to the
genus Trematis, Sharpe (1873, ut. cit.), on account of the sharply triangular

88 PALjEONTOLOGY OF NEW YORK.

foramen on one of the valves. The New York specimens have, however, not
proved so satislactorilj preserved as those of the same species from the Black
shale of Kentucky, and from a study of the latter, Mr. Ulrich has determined
the generic relations of this interesting fossil to be quite distinct from what
had been previously assumed. By the favor of Mr. Charles Schuchert we have
had the opportunity of studying Mr. Ulrich's type-specimens, and, in addition
to these, have had access to a considerable number of specimens from the Gen-
esee slate of New York. Though compelled to differ in some respects from
Mr. Ulrich's diagnosis of this I'ossil, our observations agree with his in most
essential points. The muscular impressions and fulcra are so faintly defined,
even on the best preserved specimens, that allowance may readily be made for
personal differences of observation ; for this reason, however, extreme care has
been taken to ascertain the permanent, and eliminate the fugitive characters
of this, the only species known to represent the genus.

In the pedicle-valve the groove or slit is very short, sometimes appearing as
a mere notch in the posterior margin, but, when well retained, comes to an
acute termination at a point about one-tenth the distance across the valve.
When the valve is uncompressed, this slit lies wholly on the posterior subapical
slope.

On the interior of this valve a faint ridge is continued forward from the
proximal end of the slit, extending to a point about one-third the distance
across the valve. This is flanked on each side by a low muscular callosity
which narrows anteriorly and leaves the septum projecting on the median line.
The margin of this callosity is grooved by distinct muscular impressions, and
the groove extends about the anterior edge of the septum.

The scars abutting against this callosity may be termed the centrals, and they
have essentially the same character as in the genus Obolella. From the post-
lateral margins of the callosity extend narrow curved lateral scars, reaching
to, or beyond the center of the valve, and though not always discernible they
appear with great distinctness on the best preserved specimens. At the posi-
tion of the cardinal scars as seen in Obolella, are sometimes depressions in the
shell that may indicate the point of attachment of such muscles.

BRACHIOPODA. • 89

In tlie brachiiil valve, the posterior portion of the margin is considcraljly
more flattened and that portion of tlie outline of the valve quite transverse.
Directly within this margin, and parallel to it, is a narrow thickened hand,
which may he analogous to the callosity occupying a, similar position in
Waagen's genus Neobolus. There is also a nuiscular thickening or callosity
of about the same size and cliaracter as that seen in the pedicle-valve, but
somewhat more flabellate, less distinctly defined, and not satisfactorily resolvable
into separate scars. A faint median septum begins near the posterior margin
of this area and grows in size until the anterior end is reached, whence it
rapidly disappears. No evidence has been found of curved laterals similar to
those in the pedicle-valve. Mr. Ulricii's figures show in both valves peculiar
circular scars situated near the lateral margins. These are mentioned in the
diagnosis as being "very faint" and indeed are visible only on the best pre-
served specimens, antl there only under the most favorable illumination. If it
can be demonstrated that these markings actually represent muscular scars and
are not the result of a slight exfoliation, they will prove a feature of much im-
portance. None of the forms of Obolella., or allied genera known in })riniordial
or Silurian faunas, show a combination of the elongate curved lateral scars with
such additional impressions, and we find an analogous occurrence only in tlie
genus Lakhmina, CEhlert, from the Salt Range of India,* a genus with a well-
developed platform, remarkable not only as being the earliest representative of
the Trimerellids, but also for its synthetic characters, for in association with
the " laterals," or outside marginal scars, which undoubtedly represent tlie
terminal impressions of the crescent, are the peculiar curved laterals of
Obolella. Better material must be examined in order to determine the ex-
istence or non-existence of these crescent scars in Sciiizouolus. This genus,
with our present knowledge, appears to be a very late representative of the
true obolelloid type, as pointed out by Mr. Ulrich, varying therefrom more
in the character of its pedicle-slit and cardinal area than in any other
feature, Init in its triangular pedicle-opening indicating a relationship to
Trematis and Schizocrania.

* See Waasen, Mem. Geol. Sui-vey of India, Salt Kange Fossils, vol. i, pt. iv, fuse. 5, p. 764, pi. Ixxxv,
fig. 6, 1885 ; Damdsonella linguloides.

90

PALEONTOLOGY OF NEW YORK.

Externallj the shell is characterized by its posterior apices, fine concentric
strife, and general similarity to " Discina." The shell-substance is tenuous and
appears to be wholly corneous.

Genus D 1 S C I N 0 L E P I S , Waagen. 1885.

1885. DincinalfpU, Waagen. Mem. Geol. Survey of Inili;i, Pjilxoiitoloffia Indica: Ser. xiii, Salt-Rang-e

Fossils, I. I'l-odiictus-linifistoiie Fos.sils, iv (fas. S), Brachiopoda, p. 749.

Diagnosis. " The sliell is of very small size with two unequal valves, which
are very llat, leaving scarcely any room for the animal between them.

" The lower ventral valve is hardly at all
vaulted in any direction, and appears flatly
spread out like a small fish-scale, only the
apex is a little elevated. It is removed from
the margin towards the median part of the
valve. The mar"in of the valve nearest the JM^rh,ohpisffra,miata.

•^ Alter Waagen.

apex is broadly cut out by a deep incision riG.45. PcUcie-vaivu. fig. w. Brachial vaive.
reaching to the top of the apex.

" The upper or dorsal valve is in shape similar to the other one, with a
slightly elevated eccentric apex, but without an incision.

" The surface in Ijotli valves is eitlier smooth or covered with a fine gran-
ulation." (Wa.\gen, loc. cit.)

Type, Disc.inolepis granulala, Waagen. Pi. Ixx.xvi, figs. 5-7. " Obolus Beds,"
Salt Kan<re = Primordial.

% ./-.

Genus K U T O R G I N A , Billings. 1861.

plate IV, FIG.S. 10-20.

I8C1. ObolttS, ISiLLiNa.s. Geology of Verinoid, vol. ii, p. 946.

1861. Kutmr/hia, Bili.tnos. Geology of Vermont, Vi-1. ii, p. 948 (foot-note).

1863. Obolns, Obolella, Bilt.inus Geological Survey of Canada, pp. 248, 284.

1864. OholeUa, Holl. Quai'ferly Journal Geological Society, vol. xxi, p. 101.
186,5. Obolus, Obolella {Kutorc/lna), Bii,i,[N(i.s. P.ala^ozoic Fo.ssils, vol. i, pj). 6, S.
1866. Obolella'^, Davidson. British .Silurian Brachiopoda, p. f!'2.

1865. Kutorgina, Davidson. Geological M.agazine, vol. v, p 312.

1871. Kutorgina, Davidson. British Silurian Brachiopoda, Appendix, p. 342.

1873. Iphidea (??), Mkkk. Sixth Ann. Rept. U.S. Geological Survey Ten-., p. 479.

1874. T'-ematU', White. Geogr. and G(!ol. Surv. West 100th Meriil., Prelim. Kept., p. G.

1875. Treiimtinf. Wuitk. Geogr. and (Jeol. Surv. West lOOlh Mei-id., Final Rept., vol. iv, pt. i, p. 36.

BRACHIOPODA. 91

1 876. KiUni'flhia, Li.vnausson. BrachioiindM of (lie Parjuloxi.les Beils of Sweden, p. 25.

1877. KiUorgina. IIai.l and Whiti'ikli). U. S. Geoloffieal Exploration Foi-lii-th Parallel, p. 'JOT.
1SS3. Kiitiirghia, Davidso.n. Briti.sh Silui'ian Uraciliiopoda. Supplement, j). 212.

1884. Kutorgina, Walcoit. Pateontolofjry Eureka Di>stri(:t, pp. 18-21.

lS8a. Kutorgina, Ma-ithkw. Illustrations of the Fauna of the St. John Group, No. :i, ]>. .12.

1886. Kutorgina, Walcoit. Bulletin No. 80, U. S. Geological Survey, pji. 101 107.

1887. Kutorgina, Walcoit. Anieiican Journal of Science, vol. xxxiv, p. li)(i.

This genus was fouiuled by Mr. Billings on certain obelloid lassils wliich he
had previously referred to the genus Obolell.v. In a foot-note to his descrip-
tion of the .species Obolella dngulata, he suggested* the deviation of this form
from 0. chromaiica, in tlio elevation of the beak of the dorsal valve, which in
his judgment implied an area and probably a foramen. The muscidar impres-
sions were indicated as " two large, oval impressions faintly impressed, but still
distinctly visible" with "no trace of the lateral scars." The name Kutorgina
was proposed in the event of this species not proving congeneric with 0. chro-
matica.

Among subsequent students of these fossils, no one has given so thorough a
discussion of their characters, or has had access to such complete material, as
Mr. C. D. Walcott. We therefore present the diagnosis of the genus as for-
mulated by him.f

" Shell inequivalve, transverse or elongated ; hinge-line extended iiearh to
the width of the shell.

" Larger or ventral valve convex, elevated at the beak, which is straight or
incurved, with or without a mesial sinus ; area narrow, or without a true area ;
when present it is divided by a wide open fissure. Smaller or dorsal valve Hat
or slightly convex, beak marginal.

" The areas of both the ventral or dorsal valves of the species which we have
showing them, are very narrow, and the fissure between them broad and rela-
tively large. A number of thin longitudinal sections, cut so as to cross the
beak, and also out on the cardinal edges, fail to show any covering to the fissure,
and the area appears a little more than the reflexed shell, as the lines of growth
of the valve extend over and upon it.

'■ Exterior of valves marked by concentric stria) or lines of growth that
terminate on the cardinal edges of the valves, as in K. cingulata ; nearly smooth

* Geology of Vermont, p. 948. ISBl ; Palaeozoic Fossils, vol. i, p. 9. 186").
t Bulletin No. 30, U. S. Geological Survey, pp. 101, 102.

02

PALEONTOLOGY OF NEW YORK.

Kutorginn cingnlntn.
AUur WaI.coJ 1.
Figs. -47, 48 Brachial :m<l pronie views.
Figs. 49. Interior of a Ijrachial valve.

and shiny, us in K. Lahradorica ; like that of Trem.\tis, K. pamula, or Lingul-
ELLA, K. sculptilis.

" The interiors of the valves of
the only species we have showing
the interiors, K. cingulata, have
numerous radiating stria? extend-
ing from the beak outward toward
the margins of the shell.

" In the interior of the ventral
valve four pairs of scars extend
from the beak forward as shown in figure 1 d, pi. ix.

" The interior of the dorsal valve is divided midway by a narrow mesial
rid'i-e that separates two pairs of scars [adductors ?J ; the anterior pair small.

" Shell-structure calcareous (A', cingulata, K. Whilfieldi), or horny {K. Lahra-
dorica, K. sculptilis)."

Type, Kutorgina cingulata, Billings.

Although the foregoing diagnosis furnishes many details of this group of
shells, it must be admitted that it is still insufficient to establish a satisfactory
comprehension of the generic characters or taxonomic position of Kutorgina.
Specimens of K. cingulata, from Swanton, Vermont, K. Latourensis, from Port-
land, N. B , and A'. Prospeclensis, from Lone Mountain, Nevada, which have been
at our dispo.sal, fail to add any features of importance.

In this genus we meet shells often of considerable size when compared with
the associated brachiopods in primordial faunas, having in the type-species at
least, a high, incurved pedicle-valve with the form of an Ambocgelia, and a
subapical slope ("false cardinal area"), \yhich, according to Walcott,* is
" without the trace of an opening," although this feature does not agree with
the diagnosis above given, nor with the characters of the subapical area in other
species referred to the genus, where the open fissure appears to begin at the
apex and widen downwards, having very much the character seen in the genus
Ortiiis. The opposite valve, with its highly elevated marginal apex and very
slightly developed area, can come into contact with the pedicle-valve only at

liulletin No. 30, U. S. Geological Sui-vey, p. 103.

BRACHIOPODA. 03

the extremities of the cardinal line, thus leaving a great gap between the
valves, into which the pedicle-fi.s.sm-e merges.

This feature, if established, is without an hoinologue among the brachiopods,
although its function may be regarded as a means of passage for the pedicle
similar to that found in all the biforate articulated brachiopoda. It does not
appear I'roni the descriptions of other species of Kutorgina that the brachial
valve is as elevated as in K. cingulala, but it is yet to be ascertained how far
the apparent flatness of this valve has been due to [)ressure in fossilization.
Mr. Matthew, in the description of his .species, K. Latourensis* has mentioned
the existence of " a minute tooth on each side of the very narrow and small
foramina! opening." But this important character requires verification, for
not only are the St. John .specimens of Kutorgina small and fragile, but have
usually been subjected to more or less distortion, which might readih- develop
irregularities easily mistaken for jiermanent features.

The general character of the umbonal region in the pedicle-valve would in-
dicate a certain degree of similarity in Kutorgina and Ackotreta. In the
latter genus the furrow on tiie cardinal slope appears to have been due to the
closing of the pedicle-aperture by the progressive accretions to the shell, in-
volving a modification of the surface and its concentric growth-lines; while in
Kutorgina the primitive apical aperture has been left unclosed.

The internal or muscular impressions are also imperfectly known and at
present furnish no as.sistance in establishing the affiliations of the genus.

A very close ally of Kutorgina, in size and all external features except the
cardinal characters of both valves, is the Russian genus Volborthia, von Moller
(q. v.). The latter has full, rounded umbones on both valves, and the high area
of the pedicle-valve is crossed, not b}- an open fi.ssure, but by a convex ridge;
the shell is described as having no foramen. The beak of the l)rac'liial valve
lies close against the cardinal edge of the opposite valve, leaving no hiatus as
in Kutorgina.

Under the notice of the genus Schizopholis, Waagen, we have referred to
the similarity of its type-species and Kutorgina Latourensis, Matthew.

* Illustrations of t"he Fauna of the St. John Group, No. 3, p. 42. 1885.

94 PALEONTOLOGY OF NEW YORK.

Of Kdtorgina the following species have been described by American au-
thors: K. cingulata, Billings (/oc. f?7.) ; K. sculptilis, Meek {Iphidea?? sculpUlis,
Meek, referred to Kutorgina by Mr. Walcott*) ; K. pannula, White (Trematis?
pannulus. White, referred to Kutorgina by Mr. Walcottj) ; K. minutissima,
Hall and Whitfield ;i Mr. Walc'OTT§ makes this name a synonym for K. sculp-
tilis; K. Prospedmsis, Walcott ;|1 K. Whitfieldi, Walcott ;1T K. Labradorica, 'QW-
Wngs** =^Obnlus Labradoricus, Billings, referred to Kutorgina by Mr. Walcott;
K. Latourensis, Matthew ;ff X. pterineoides,%X Matthew.

In 1868, Davidson identified the species Obolella Phillipsi, Holl, from the
Lingula Flags and Lower Tremadoc, as K. cingulata, Billings, and in 1876, Lin-
NARSSON described from the Paradoxides beds of Sweden a similar form as K.
cingulata var. pusilla.

All the representatives of this genus known are from primordial faunas.

Genus SCHIZOPHOLIS, Waagen. 1885.

188.5. 5'c/(izo;jAo?is, Waagen. Mem. Geol. Surv. Imlia. PaUeoiitologia ludii-a : Ser. xiii, Salt-Range

Fossils, I. Prodnctus-limestone Fdssils ; iv (fas. y), Bi-achiopoda, p. 752.

" The shells belonging to this genus are all of very small size. They con-
sist of two valves, of which one is imperforated and rather fiat, the other is
slightly elevated with a somewhat prominent marginal apex, below which is a
small triangular area slit open in the middle by a triangular fissure, which seems
to be sometimes a little widened at the top, forming a kind of foramen, placed
just at the extremity of the apex.

" The .shell-surface is finely granular, and it seems as if it had borne spine-
like appendages as in Siphonotreta, but these are not preserved in any of the
specimens at my disposal.

" Of the internal characters of the genus nothing is known to me, as there
are only three specimens available ; and as the rock, a black micaceous shale,

* Palseontology Eureka District, p. 20.

t Bulletin No. 30, U. S. Geological Survey, p. lOf).

I U. S. Geolog-ieal Explor.ation Fortieth P.arallel. vol. iv, p. 207, pi. i, tigs. It, VI.

§ Paleontology Eureka District, loc. cil.

1 Palaeontology Eureka District, p. 19, pi. ix, tigs. 1 a, b.

H Palaeontology Eureka Disti-ict, p. 18, pi. ix, tigs. 4, 4 a.
** Palteozoic Fo.ssils, vol. i, p. (i.

tt IlUistr.itions of tlie Fauna of the St. .John Group. No. :{, p. 42, pi. v, tigs. 18 a-c.
n Illustrations of the Fauna of the .'^t. John Group No. 3, p. 43, pi. v, fig. 19.

BRACHIOPODA. 95

adhered very firmly to the internal side of these shells, it appeareil impossible
to make a preparation of the inside." (Waagem, ut. cit.)

Type, Schizopholis rugosa, Waagen, pi. lx.\xvi, figs. 2-4. 0})ohis Reds,
Salt Range = Primordial.

This genus, represented by a single species, is placed \)y

Dr. Waagen, with unquestioned accuracy, among the

Siphonotretids. Its closest alliance is with Kutorgina, or

with those species of that genus which have afforded

definite evidence of an open fissure on the subapical area,

/. e., K. Latourensis, Matthew, A', pannula. White. This

feature has already been given ainong the generic characters

of Kutorgina, but it may be held subject to reservation, t:.; ,//

since positive evidence of its existence in the t\'pe-species, "•'

K. cingulata, Billings, is still wanting. The resemblance .>,,....;„■. .'■-"

-Vner Waagen.

between K. Latourensis ami Schizopholis rugosa is most fig. so. i-cdicie-vaivc, ivont

view.

striking in every essential respect, and should the former i-"i« si cai-iinai view,
not prove congeneric with A', cingulata, it nuist be referred to Schizopholis;
converse!}', if these species are congeneric, it would appear that Schizopholis
must be considered a synonym for Kutorgina.

Genus V 0 L B 0 R T H I A , von Moller 1878.

1847. Acrotreta, KinoiwA. VeilKiiidl. Kills. Miner;il. Gesellsch. zu St. Petei-sbm-g-, p 'JT", pi. vii, lij,'- 9.

1873. Volbortlda, von JVIoller. Veilmiidl. Kais. Mineijil. Gesell.=ch. /.u St. Petei-sl)urg-, pi. vii, fig. 9.

1874. Volhwthia, vox Moller. Ntnie.s Jahrb. fiir Miiioi-aloj,'ie, ("tc. Heft 5, p. 140. pi. vii, figs. 1-6.

Type, Acrotreta recurva, Kutorga. Lower Silurian (= Primordial ?).

The genus is founded on the third of Kutorga's species of his genus
Acrotreta, a form of very large size compared with the type of the genus.
Kutorga's description covers only a single ^ot^^ ''"^ ^

pedicle-valve, from which the apex was broken. '^_ \ i'^-^'^

The better examples described by von Moller
show that the shell-substance is calareo-corneous
and finely punctate. In general form the shell
suggests a "cornucopia, the mouth of which is

i^olborlhia recurr>i.

Alter vo.v »l(.i.i,EK.
FIG. 52. Pionic
FlO. 53. CnnJin.'iI view.

96 PALEONTOLOGY OF NEW YORK.

closed l)v a very convex cover. Viewed IVom above, the outline of tlie shell is
transversely oval, the posterior margin, the length of which has about one-
half the diameter of the shell, being straight. The ventral valve is elevated
and conical, and pos.sesses an incurved and inflated umbo with no foramen.
Between the beak and the posterior margin is a sharply defined, elevated, tri-
angular area, which is divided by a low, convex ridge passing from the beak to
the margin.

" The dorsal valve is convex, though much more depressed than the ventral,
and has a beak similar to that of the latter. Although this beak lies in the
same vertical line with that of the oppo.site valve, it rests directly upon the
posterior margin of the valve, and has no area. The surface of the valves is
smooth and covered only by fine concentric lines, which are continued without
interruption over the area of the ventral vii,lve. *****

" Neither valve appears to possess any internal apophyses, at least the inter-
nal casts show no trace of them. The muscular impressions are unknown, the
casts showing only a small number of widely divergent radiating lines." (von
MoLLER, vt. cit.)

The similarity of this shell to Kutorgina in general form and surface-features,
is at once apparent. We meet, however, a conspicuous difference in the areal
ridge of Volborthia, a feature strongly suggestive of the " pseudo-deltidium "
of the articulate brachiopods. It is precisely similar to tlie areal ridge in
IPHinKA, and the exact counterpart in form of the areal furrow in Acrotreta ;
its origin may be similarly explained, and a complete analogy may be found, in
this respect, in the genera with the foramen-scar ecurved as in Volborthia
and Iphioea, incurved as in Acrotreta and Conotreta, and open as in Kutor-
gina and ScHizoPiiOLts. While we must admit the absence of an external fora-
minal aperture in the material so carefully studied and satisfactorily illustrated
by Professor voN M()LLER, we are led to surmise that this character, often so
obscure and difficult of detection in such fossils, will eventually be found. The
shells of Volborthia, like those of Kutorgina, are of very considerable size, an
example cited having a length of 14 mm., a width of 19 mm. and a height
of 16 mm.

BRACHIOPODA. 97

Genus IPIIIDEA, Billings. 1872.

PLATE IV, FIGS. G-9.

1872. Ipkidea, Billings. Canadian Naturalist, New Series, voL vi, p. 477.

" 1874. Iphidea, Billings. Palseozoic Fossils, vol. ii, pt. i, p. 76.

1876. Iphidea, Linnaes.wn. Brachiopoda of the Paradoxide.s Bed.s of Sweden, p. 25.

1886. Iphidea, Walcott. Bulletin No. 30, U. S. Geolo-^ical Survey, p. 100.

Diagnosis. " Of this genus we have no specimens showing the internal
structure, but the external characters seem sufficient to separtite it from any
described generic group. The ventral ? valve of /. bella is conical, strongly
elevated at the beak, hinge-line nearly straight, posterior angles narrowly
rounded, sides and front nearly unilbrmly rounded, forming rather more than
a semicircle. Posterior side with a large false area anda convex pseudo-delt-
idium, the Avidth of which at the hinge-line is nearly one-third tiie whole
width of the shell. The dorsal valve is semicircular, moderately convex, most
elevated at the beak The hinge-line appears to be straight. * * *
The surface is covered with fine concentric striae, which in the ventral valve
are continued around on the area."*

Type, Iphidea bella.

The foregoing diagnosis is derived from the original description of the type-
species, Iphidea bella.' After the lapse of eighteen years since the date of its
publication little has been contributed to our knowledge and no facts of
es.sential importance bearing upon the external characters ofthe.se shells;
of the interior we still know nothing. In 1873, Mr. Meek described the species
Iphidea (J?) scidptilis,f from the Gallatin River, Montana, but as the hinge-line
and subapical area of the shell have not been observed, and on account of its
apparent specific identity with the Kutorgina minutissima, Hall and Whitfield, it
has been referred provisionally to the genus Kutorgina by Mr. Walcott, and
the latter species reduced to a synonym. i Dr. Lin.varssox described the species
I. ornatella, from the Paradoxides beds,§ giving good figures of the exterior of

* Billings. Canadian Naturalist, 1872, loe. cit.

i Pieliminary Pal^ontol. Kept. : Sixth Ann. Rept. U. S. Geolo-fieal Survey T.m r., [p. 479.
t Palaeontolog-y Eureka District, p. 20.

§ Brachiopoda of the Paradoxides Beds of Sweden : Bilian^' till K. Svenska V.-t Akad. handlingar, Bn.l.
3, No. 12, p. 25, pi. iii, figs. 42, 43.

98 PALEONTOLOGY OF NEW YORK.

botli Viilvt's, and it would be difficult to indicate essential differences in the
general form and proportions of this species and /. bella*

Notwithstanding the fact that our knowledge of these shells is so circum-
scribed, certain of tlieir features are of definite generic value.

The apical foramen indicates the close alliance of the genus
with AcROTRETA and Acrothele, and may be considered as an inter-
mediate stage in the forward progress of the pedicle-aperture from
its intermarginal position in the linguloids and oboloids, to its •'■;^,.^^.;- ^'f^;;™''-
excentric position and tubular character in Schizambon. The tiattened subapical
slope is a feature also seen in Acrotreta, while the convex foraminal covering
on this area, which gives to the shell an appearance so suggestive of Orthisina,
is found in the inarticulate brachiopods only here and in Volborthia. The shell-
substance is corneous, apparently consisting of but few layers.

The originals of Mr. Billings' /. bella were from Trois Pistoles, near Quebec ;
" a closely allied species of the same genus occurs in the primordial limestone
at Topsail Head, Conception Bay, Newfoundland" (Billings, toe. cit.). The
specimen here figured on Plate IV (figs. 8, 9), is from Georgia, Vermont.
We have before us specimens of a species from the Grand Canon, Arizona
(Tonto group of Walcott := Potsdam sandstone?), which. bears a more promi-
nent areal ridge than 7. hella, and has the cardinal edge elevated above the
rest of tbe margin of tlie valve, a feature strongly marked in Linnarsson's
species, /. ornatella.

Genus ACROTHELE, Linnarsson. 1876.

PL.'VTE III, FIGS. 25 31.

IStiS. Liugiila, Hartt. Dawson's Acadian Gt'ology, Second Edition, p. 044.

1876. Acrothele, Linnau.sson. On the Brachiopoda of the Pai-adoxides Beds of Sweden, ji. 20.

1879. Obohis?, Barrandk. Systenie Silui-ien dn Centre de la Bohi'me, vol. v, jil. 102, tig-, vii.

1879. Disclna, Barrandk. Systiinie Silni-iou dn Centre de la Boheme, vol. v, pi. 110, tig. vii.

1881. Acrothele, "White. Proceedings United States National Mnsenm, vol. iii. p. 47.

1883. Acrothele, Davicsox. British Silnrian Brachiopoda, Snpplenient, \>. 214.
'! 1884. Acrothele?, Walcott. Palffiinitology Eureka District, p. 14.

1884. Acrothele, Walcott. Bnlletin No. 10, Uiuted States Geological Survey, p. 15.

* Mr. Walcott has promised additional details in I'egard to this genus (Bulletin No. 30, U. S. Geological
Survey, p. 100), which will be looked for with interest.

BRACHIOPODA. 99

1885. Acrothele, Matthew. Transactions Royal Society of Canada, .■mmiuiii i\ , i>. ;Sii.
188G. Acrothele, Waloott. Bulletin No. 80, United States Geolofe'ical Survey, ji. 107.

Diagnosis. " Shell corneous, composed of several laminaB, the inner smooth
and polished, the outermost one rough and opaque. Ventral valve slightly
conical, with excentric umbone, pierced by a minute foramen, in front of which
there are, at least in one species, two small wart-liUe protuberances ; the field
between the umbone and the posterior margin is usually a little llattened, thus
forming a slight indication of a false area. Dorsal \alve with marginal I'un-
bone, consisting of two wart- like protuberances. In the interior of the dorsal
valve there are two oblong, diverging muscidar scars, close to the posterior
margin, and two small rounded scars near the middle. The muscidar scars are
separated by a longitudinal ridge."*

Type, Acrothele coriacea, Linnarsson.

Observations. With the interior characters of this genus and those of the
closely related group Acrotreta imperfectly known, the essential distinction at
present recognizable in the two is in the relative development of the subapical slope.
This feature in Acrotreta is often very conspicuous, producing strikingly conical
shells which have their apices truncated by tlie foraminal opening and the
posterior moiety of the surface nearly vertical. In Acrothele the foramen in
the pedicle-valve is also apical, but the slope from the apex to the posterior
margin is gentle, often scarcely defined. The small wart-like protuberances
lying in front of the foramen, as indicated by Linnarsson for the type-species,f
and also seen in the accompanying figures of ^. Matthewi, Hartt (Plate III, figs.
25-29), have been made from the illustrative specimens used by Mr. Matthew.ij:
Though the function of these bodies may not be understood, they appear to be
homologues of the apical callosity in Acrotreta (e. g., A. Baileyi, Matthew),
and the mammiform swelling about the foramen in Siphonotreta. In the
interior of the brachial valve, the most persistent feature, as far as observed, is
the axial ridge, which is sometimes accompanied by faint diverging muscular
ridges on either side near the beak {A. Matthewi), dividing the halves of an obscure
circumbonal muscular impression. ' .

* LiNNAHSscix. On the Br.-ichiopoda of the Paradoxides Beds of Sweden, p. 20.

+ Linnarsson. On the Brachicpo.la of the Paradoxides Beds of Sweden, pi. iv, fig^. iib, VM>.

X Transactions of the Royal Society of Canada, pi. y. 188.">.

100 PALEONTOLOGY OF NEW YORK.

In A. coriacea Lixnarsson found small circular scars in the middle of this
valve, abutting closely against the median septum. The septal characters seen
in the two species mentioned are also shown in Walcott's figures of A. sub-
sidua, White,* Mr. Matthew has described some features of the hinge-line as
follows: "Just within the posterior margin [of the pedicle-valve] there are four
minute pits, of which the two inner correspond to small tooth-like projections
of the dorsal valve ; the two outer ones are opposite the posterior ends of the
comma-shaped grooves of the umbonal depression."! We are not confident
that we have been able to detect these characters satisfactorily on Mr. Mat-
thew's typical specimens, but the suggestion has already been made that with
fossils as liable to distortion and imperfect preservation as these frail bodies,
great caution is needed in the separation of permanent and fugitive features.

The shell-substance in this genus is essentially corneous and, as observed by
LiNNARSSON, is composed of several lamin?e. The surface is usually devoid of
other ornamentation than concentric growth-lines, but in A. granulata, Linnars-
son, A. subsidua, White, and A. Matthewi, Hartt, the concentric lines are more
or less interrupted, producing a granular or papillate appearance.

The known species of Acrothele are few, and all its American representa-
tives belong to primordial faunas. In 1874, Dr. White described, under the
name Acrotreta ? siibsidua,t a species from Antelope Springs, Utah, which he
subsequently (1880, loc. cit.) referred to Acrothele. Mr.WALCOTT, in 1884,§
referred to this geims the Lingula Matthewi of Hartt, from the St. John group, ||
and, in the same year, described the species Acrothele ? dichotoma,"^ from the
Prospect Mountain group of Nevada. This species, however, bears a very
distinct subapical slope, and was' subsequently transferred by its author to the
genus Acrotreta.** Of the two species described by Linnarsson, A. coriacea
and /(. gramdata, the latter has been reported by Dr. Davidson, from the Upper

* Bulletin No. 30, United States Geological Survey, pi. ix, figs. 4 a, 4 c.
t Transactions of the Royal Society of Canada, p. 40. ISS.*).

I Geofji'aphicul and Geolog-ical Exploration West of 100th Meridian ; Pi-elim. Rept. Invert. Foss., \t. 6.
§ Bnlleliii No. 10, United Statf.s Geological Survey.

II Mr. Matthkw has designated two varieties of this sjunries: (a) jirlm((, (h) lata.
*i\ PaliEontology Eureka District, loc. cit.

** Bulletin No. 30, United States Geological Survey, p. 107.

BRACHIOPODA. 101

Llandcilo at Coal-pit Bay, county Down, Ireland. This is a species which it
is manifestly diiTicult to separate from either A. subsidua or A. Matthewi by any
external or internal characters.

The Obolus ? Bohemicus, Barrande * from the Etage C, and Discina secedens,
Barrande,f from the Etage D, appear to l)elong to this genus. Barranue's
figures of the latter species show very distinctly the two tubercles or callosities
hnng in juxtaposition to the inner opening of the foramen.

Genus ACROTRETA, Kutorg.\. 1848.

PLATE m, FIGS. 3-2-,il.

1848. Acrotreta, Kutorga. Vei-hamil. der russ.-kais. mineral. Gesellsch. zu St. Petei-sburg, p. 275.

1853. Acrotreta, Datidsox. Introduction Briti.sh Fos-sil Bi-acliiopoda, p. 133.

1865. Acrotreta, ton Seebach. Zeitschv. der deutscli. geolog-. Ge.^ellsch., vol. xvii, ]i. 341.

1865. Acrotreta, Billixgs. PaUeozoii; Fossils, vol. i, p. 21G.

1871. Acrotreta (?), Davidsox. British Silurian Brachiopoda, p. 343.

1872. Acrotreta, Meek. Sixth Ann. Kept. U. S. Geological Survey Terr., p. 403.

1874. Ai-rotnla, White. Geograjiliical and Geological Exploration and Sui-vey West lOOtli Meridian :

Prelim. Rept Invertebrate Fossils, p. 9.

1875. Acrotreta, White Geogiaphical and Geological Exploration ami .Survey West 100th Meridian :

Final Rept., vol. iv, pt. 1, p. 53.

1876. Aei-otreta, Llvxarssox. Brachiojioda of the Paradoxides Beds of Sweden, p. 16.

1883. Acrotreta, Davidson. Briti.sh Silurian Biachiopoda, Supplement, p. 213.

1884. Acrothele?, Waicott. Palaeontology of the Eureka District, p. 14.

1885. Acrotreta, Matthew. Illustrations of the Fauna of the St. John Group, No. 3, p, 36.

1886. Acrotreta, Walcott. Bulletin No. 30, Tniteil Sl.ates Geological Survey, p. 98.

Di.\GNOSis. " Dorsal [pedicle-] valve conical ; the cardinal face of the cone
tiat, having a triangular form and resembling a cardinal area. From the apex
to the center of the base of this area runs a shallow groove, which may be
taken as an indication of a deltidium. At the upper extremity of this groove
is the suboval external opening of the sipho, which is inclined toward the
cardinal side. Ventral [brachial] valve flat, with a distinct marginal apex.
Upon the external surface of the shell are only delicate concentric growth-
\vrinkles, which are continued over the groove on the cardinal surface ; no
tubercles or spines. Cardinal margin straight."!

Type, Acrotreta subconica, Kutorga.

* Systeme Silurien Boheme, vol. v, pi. 102, tig. vii ; ] . 2, 3.
1 Systfcme Silurien Boheme, vol. v, pi. 110, tig. viii.
J Kdtorga, Joe. (it.

102 PALEONTOLOGY OF NEW YORK.

KuTORGA described three species of this o;enus, of whicli the foregoing is the
first. The others, A. disparirugata and A. recurva, vary considerably from the
type-species in the degree of incurvature of the high pedicle-valve, and in the
definition of the subapical area and the groove upon its surfixce, so that it will
be important to establish the conception of the genus strictly upon the features
of the first species.* Externally these shells are most closely related to Acro-
THELE, with which they agree in the relative positions of the umbones, and in
the perforation of the pedicle-valve. As observed under the discussion of that
genus, the distinguishing character is found in the different elevation of the
pedicle-valve, and the lack of any well defined subapical area in the latter
genus.

Until the studies of Mr. Walcott and Mr. Matthew upon the Ameri-
can species of this genus were made public, nothing of importance
was knoAvn in regard to its internal charficters. The former writer, in
1884,1 represented a cast of the interior of tlie pedicle-valve of A. gemma,
with a somewhat broad excavation about the pedicle-aperture, which
would give to the interior of the valve an apical swelling or callosity, penetrated
by the foramen. Mr. Matthew, in 1885, gives a figure of the interior of this
valve in A. Baileyi,X showing the same character
with the addition of two pits (tubercles) close
upon, but just in front of the foraminal opening. , *;.

If this latter feature can be established it -- " \\

furnishes another similarity to AcnioTHELE ; but,
with the original specimen in our hands, Ave ''^^gs>' "^<=saiSsi^

" '■ Acroireta gemma.

nnist confess our inability to distinguish any- ^,„ ,, ,nt:^ZZ^^^ y^.e

UJ.1 aj * • /' Ji J 1 Fig. 56. Canlinal view of pedicle-valve.

ung more than the nnpre.ssion ot the central 10,0.57. mtemai cast of apicai portion.

callosity (Plate III, figs. 32, 34). Mr. Walcott's figure shows elongate muscular

scars surrounding the foramen and diverging forward. The interior of the

brachial valve of A. gemma (Walcott's figure la;" ventral valve " in error),

shows a stout median ridge, which is widened near the apex of the valve and

*'Acrolreta reairva, Kutoi'ga, has been taken by von Mollkr as the type of the genus Volborthia (q.v.)

t Pateontology of tlie Eureka Distinct, pi. i, figs. 1 a-f.

; lUnstratinns of the Fauna of the St. John Group, No. H, jil. v, i\g. Vic.

BRACIIIOPODA.

103

ifboldltt Sahriiuv.

After Davidson.

Fu;. ')S. Internal cast of

brachial valvt*.

Acrotretii Xirhohoiii.
After Davidson.
Fig. 50. Interior of brach-
ial valve.

flanked by cardinal (?) scars, in (Vont uC wliidi iuv two smaller impressions.
Essentially the same features are seen in Mr. Matthew's figure* of the interior
of this valve. The interior of the brachial
valve of A. gemma is compared by Mr. Wal-
COTT to tliat of the Oholdla Sabrime, Calla-
way, as represented Ijy Davidson.! The
agreement is essentially complete in these
respects, and Mr. Davidson's figures of the
pedicle-valve of this species give it a great
elevation and an indistinct cardinal area, though they do not show the apical
foramen. It is highly pi'obable that the species will prove an Acrotreta.

The vertical groove on the cardinal area is, like the elevation and definition
of the area itself, a very variable feature. In A. subconica, A. gemma, and A.
Nicholsoni it is sharply defined, while A. disparirugata, Kutorga, A. Baileyi Mat-
thew, and A. socialis, von Seebach, l)ear less definite indications of this character.
The suggestion offered by Kutorga, that this furrow may be taken as an " in-
dication of a deltidium," may l)e understood as not implying more than a remote
homology with the deltidium of the articulate brachiopods.

We have yet but few American representatives of this genus. In I8O0, Mr.
Billings described the first known American species, A. gemma, and Mr. Wal-
COTT (1884) has considered the species regarded by Meek (18T2) as A. subconica,
Kutorga,! from the Gallatin River, Montana, and the A. pyxidicula, White (1874),
from Nevada, as synonymous with it. Acrothele? dichoioma, Walcott (18 4),
from Nevada, has been subsequently referred by its author (188G) to Acro-
treta, while Acrotreta subsidua, White (1874), is referred to Acrothele. Mr.
Matthew has described (1885) Acrotreta Baileyi and A. ? Gulielmi, from the St.
John group ; the latter of these is a representative of a distinct genus, which
is discussed in tlie following pages under the name Discinopsis. All the
American species are from primordial faunas; A. socialis, von Seebach, is

* Illustrations of the Fauna of the St. John Group, No. 3, pi. v, tig. 13.
t British Silurian Bi-iii-hiopoila, Supplement, pi. xvi, fig. 27 il.

I This form Mr. Meek i.ropo.^eil to name A. alteJimita, in ca-se it proveil lii.-itinp.t from tlu- Rnswian
species.

104 PALEONTOLOGY OF NEW YORK.

from the Paradoxides Beds ; A. subconica and A. disparirugata , Kutorga, from
the primordial heds of Russia ; A. Nicholsimi and A. ? costala, Davidson, from the
Llandeilo. The Last species is strongly ribbed on its exterior, but its generic
rehxtions are too micertain to allow this fact to be regarded as adding a new
feature to the genus.

Genus CONOTRETA, Walcott. 1889.*

PLATE IV K, FIOS. 16-21.
1889. Conotreta, Walcott. Proi^eeciings National Museum, vol. xii, No. 77i5 ; Advaiu^e Sheet, Dec. 10.

Diagnosis. The pedicle-valve is conical, its height being greater than its
length. The apex is more or less broken on all the specimens, but in a single
minute valve from Covington, Kentucky, there is evidence of the external
opening of the siplio. From the apex, a shallow furrow extends to the poste-
rior margin, increasing in widtli downward. In the smaller specimens the
posterior wall of the shell conforms to the curvature of the rest of the surface,
interrupted only by the longitudinal depression, but, with increase in size,
this area becomes distinctly flattened, as in Acrotreta. Surface covered with
sharp concentric striae which make a slight upward curve as they cross the fora-
minal groove.

The casts of the interior show a strong apical callosity surrounding the
probable position of the foramen. This is somewhat produced anteriorly into
a short sharp ridge, on either side of which lie two other ridges, with evidence
of a third on the lateral slopes. Upon the largest of the specimens these ridges
seem to liave been hollowed at their extremities.

Type, Conotreta Rusti, Walcott.

* In a preliminaiy list of the genera of the luilaeozoio l)i-achiopoda, iniblished in the Eighth Annual
Report of tlje Stale Geologist, 1889, p. 4;i, the tei-iii (ikinitzia was used for this genus, a description of which
had at that time been pi-epared from material in our hands, obtained from the Utica horizon at Coving-ton.
Kentucky. It would have been neces.sary to with(h-aw this name, as it had already been in use for a genus
of fossil plants (E.NnLicuEK, Synopsis Coniferaruin, p. 281. 1847). Me.anwhile Mr. Walcott has described
the genus from specimens from Trenton Falls, in an advance sheet of the Proceedings of the National
Museum, privately cin-ulated. We have been jwrmitted to make use of his .specimens fin- study and
illusti-ation.

BRACHIOPODA. lOo

Observations. These shells differ from Acrotreta in their less distinctly
defined posterior .area and in the character of their internal markings. The
apical callosity is much more prominently developed and the ridges radiating
from it (two in Acrotreta, according to Wai.cott*) more numerous. The lack
of definition in the posterior subapical slope, apparent in the young shells from
the Utica horizon at Covington and the Trenton limestone at Trenton Falls,
suggests the condition of this feature in the genus Mesotreta, and also in the
species figured by M. Barrande,! from the Etage D, under the name, Acrotreta
Babel, which has an elevated, conical pedicle-valve with a perforated apex and
unspecialized posterior slope.

Genus DISCINOPSIS, gen. nov. (Matthew).

PLATE III, KIGS. 20-24.
18S5. Arrolrelaf, Matthew. IlUish-ations iif Uic Fauna of tln' St. .IdIih nniiiii, No. vi, p. 37.

From the examination of the original specimens of Mr. Matthew's species,
Acrotreta ? Gulielmi, from the St. John group, at Portland, N B., it has become
evident that the internal impressions, especially those of the perforated valve, are
of a character widely diflerent from those of Acrotreta, or, indeed, of any of
the allied genera. Upon expressing this conviction to Mr. Matthew with the
request for any additional material that might throw light on this rather
obscure shell, he kindly placed at our disposal all his specimens of the species,
and in accordance with our suggestion that it represented a new generic form
and would hence require a new name, has proposed for it the term Discinopsis.

Diagnosis. Shell subcircular in outline. Surfaee depressed-conical, apices
excentric, not marginal. Pedicle-valve with the apex truncated by a circular
foraminal aperture (?)• The interior of this valve is characterized by a pair of
deep, diverging furrows, passing forward from the beak or internal foraminal
opening, in broad curves which converge toward the anterior margin but without
meeting. These furrows enclose a thickened and somewhat elevated central
area, which, in the subumbonal region is apparently free, projecting for a short

* Palaeontolog-y of the Eureka Diati-ict, pi. i, ti^. 1 ft.

t Systfeme Silui-ien BohGrne, vol. v, pi. 95, ti^. vii. 1S79.

106 PALEONTOLOGY OF NEW YORK.

distance, like a narrow, triangular shelf, beneath which the foramen probably
opened. The interior opening of the foramen is, however, not apparent on
any of the specimens examined, for, as usually preserved, the matrix has
adhered to this subapical cavity, and in a single example only, is the shelf-like
character of the median area distinctly demonstrated. A faint longitudinal
ridge passes from the apex of the shelf to the anterior margin, but no other
markings are discernible on the interior except faint radiating or slightly un-
dulating, probably vascular lines.

The interior of the brachial valve, as far as known, shows no other charac-
ters than the radiating lines, which appear to belong to the ornamentation of
the external surface.

Shell-substance tenuous, apparently corneous. External surface covered
with more or less prominent, sometimes lamellose concentric growth-lines,
crossed by fine, gently curved, radiating striae which are usually more prominent
when the concentric lines are exfoliated.

T3'pe, Discinopsis Guliehni, Matthew.

The nearest alliances of this peculiar and imperfectly known fossil appear to be
with the genus Linnarssonia ; both having the apical shelf or callosity in the pedi-
cle-valve, but in the latter this is more elevated and concentrated posteriorly.
In other respects, Discinopsis differs from this genus, as well as from Acro-
THELE, in the other internal markings and in the excentric apex of the brachial
valve, while it is removed from Acrotketa by these I'eatiu'es and also by the
absence of a subapical area. The deep furrows in the pedicle-valve may be
compared to the pair of muscular (.') furrows diverging from the foraminal
opening in Acrotreta gemma, as shown by Walcott.* One of the figures given
by this author under the designation, Linnarssonia Taconica,} appears to
represent a form of Discinopsis.

* Palseontology of the Eureka Distiict, pi. i, fif,'. 1 /;.

t Amencaii Journal of Science, vol. xxxiv, [il. i, fig-. 1S». 1887.

BRACHIOPODA. 107

Genus L I N N A R S S 0 N 1 A , Walcott. 1885.

PLATE III, FIGS. 35-14.

1S66. Oboltlla, Disciiia, Saltkk. Reiit. British Association for ISl!."), p. 285.

1868. OboleUa, D.wtDSON. Geolojjical Majraziiie, vol. v, p. 309.

1S6S. Obolella, H.krti: Dawson's Acadian Geolog-y, Second Edition, p. iH4.

ISTl. Obolella (parlim), D.widson. British Silurian Bi-achiopoila, p. 339.

1S76. Obolella, L!."<iV.\r.sso»j. Brachiopo.la of tlie Pai-adoxides Bods of Sweden, p. 19.

1SS5. Linnarsso7iia, W.\lcott. Anieiiran Journal of Science, vol. xxix, p. 115.

18S5. Linnarssonia, M.XTriiivW. Illustrations of the Fauna of the St. John Group, No. 3, p. 35.

1887. Li7t>Mrssonia, W.\lcott. American Journal of Science, vol xxxiv, p. 189.

1889. Linnarssonia, D.vwso.v. Transactions Royal Society of Canaila.

Diagnosis. " Shell calcareous, transversely or longitudinally ovate, subcir-
cular ; convex in the typical species ; valves inarticulate. Ventral valve
convex, with the excentric apex perforated by a minute foramen ; no area ;
cardinal edge thin. Dorsal valve conve.x in the .species thus I'ar known ; witli-
out any area. In the interior of the ventral valve two oval and oblique scars
lie each side of the slightly raised rim surrounding the minute foraminal
opening and close to the posterior margin ; from the foraminal rim a groove
extends obliquely forward and outward on each side, so as to enclose a project-
ing y\-shaped ridge that is highest at its posterior margin just in front of the
circular foraminal opening. In the interior of the dorsal valve two large,
irregularly circular scars are situated close to the posterior margin, and separated
by a low. Hat ridge tliat extends forward, between the two small divaricator
scars."*

Type, OboleUa transversa, Hartt.

Observations. The illustrations of the internal characters of this genus,
which have been given with great elaboration by Mr. Davidson,! I'or Obolella
sagittalis, Salter, and also with instructive figures, by Dr. Li.n.\arsson,;c lor the
same species; by Mr. Walcott, for the type of the genus,§ L. transversa,
Hartt, and for L. Taconica, Walcott,|| and by Mr. G. F. Mattiie\v,1I for the
species L. transversa, Hartt, and L. misera, Billings, all produce the impression

* Walcott. American Journal of Science, vol. xxix, p. 115.

t Geological Magazine, vol. v, pi. xv, figs. 17-24: Silurian Brachiopoda, pi. 1, Hgs. 1-14.
X Brachiopoda of the Paradoxides Beds, pi. iii, figs. 30-41.
§ American Jouraal of Science, 1885, vol. xxix. p. 116.
1 Ameiican Journal of Science, 1S87, pi. i, figs. lS/<-rf.
^ niusti-ations of the Fauna St. John Gi-oup, 1S85, pi. v, fig. 1 1 a-e. \2a-e.

108

PALEONTOLOGY OF NEW YORK.

Linnarssonia sagittalis.
A Her Davidson.
Fiii. 60. Internal cast of pedicle-valve.
Fiii. fil. Internal cast of brachial valve.

that the generic characters are not only very distinctly defined, but are of such
a nature as to remove all these forms widely I'roin Obolella and its immediate
allies. This is seen in the character of the muscular impressions alone; the
absence of the great lateral scars, the broad, composite centrals, and the deep
pedicle-pit of the ventral valve, all of which are indicial features of the obolel-
loid genera ; furthermore there is no evidence of any cardinal area or anything
more than a somewhat flattened margin of
contact in either valve. On the other hand
there are present (in L. sagittalis) conspicuous
cardinal scars in each valve, of similar char-
acter to the posterior adductors of Crania (as
suggested by Mr. Davidson, loc. cit, p. 340),
which, in L. transversa and L. misera, take
the form of stout tubercles or bosses, situated just within the posterior margin;
and a mammiform or subtrihedral apical tubercle, which is perforated by a
minute foramen (see Plate III, figs. 35, 37-39, 43). This feature was not
represented in Mr. Davidson's figures of Oboklla sagittalis, but was first pointed
out by LiNNARSSON {loc. cit.), and is clearly seen in well preserved specimens.
The character of the pedicle-aperture is of itself of sufficient significance to
remove these species from the vicinity of Obolus and Obolella, where this
opening is always a groove on a well defined cardinal area, and to endorse its
association with Acrotreta, Acrothele, Schizambon, and the other allies of
SiPHONOTRETA. The posterior submarginal tubercles or bosses have undoubtedly
served as fulcra, probably of the adjustor rather than of the adductor muscles,
acting to keep the valves in place, and they may be compai'ed to the articular
bosses in the genera Spondylobolus and Barroisella.

The brachial valve has a less conspicuous development of these tubercles, but
they are distinctly seen in L. transversa, L. sagittalis and L. Taconica. Between
them lies a strong axial septum, which is broadened over the central portion
of the shell, and is accompanied for most of its length by a shorter and narrower
ridge on either side, from each of which it is separated by a sharp furrow.

The substance of the shell, in all the specimens which liave passed under our

BRACHIOPODA. \m

examination, is as distinctly corneous as in Linuula, anil from the manner of
exfoliation seen in the shells, is evidentl}- composed of successive lamintc.
The more intimate structure of the shell-substance is yet to be ascertained.

The species of Linnaussonia thus far knowu are all from primordial faunas ;
L. transversa, Hartt, and L. niisera, killings (Matthews), from the St. John };roup;
L. Taconica, Walcott, from the Taconic limestones iu Washin,^'tou county, N.
Y. ; L. preUosa, Billings, from the Quebec group, ;it fjittle Metis and elsewhere
in Canada; L. sagittalis, Salter, from the Menevian of St. David's and else-
where in Wales, in the Paradoxides beds at Bornholm, Sweden, and at Mt.
Stephen, British Columbia. The Obohlla maculata, Hicks, from St. David's, will
probably prove i-eferable to this genus.

Genus M E S 0 T 11 E T A , Kutorca. 1848.

I'l.ATE IV, I'lG. 21.

1S48. tS'ip/ioiKitreta (Mesotreta). Kiitohi;a. Ut-bei- die Br;icliioiHHloii-l''!imilie cl<;r Siiilioiu)treta;a' ; Ver-
hanill. del- I'lis-s.-kais. mineral. Gt'.<iellsdi. zii St. Petersburg. .Iiihrg-. 1847, p. 271,
pi. vii, fig. 4 a, I/, c.

1S71. Siphuuotreta, QvEtiSTKDT. Petrefakteiikmnle Deutselilnncls; ISrachioiio.leii, )>. i;74, pi. 61. fif:. 33.

Diagnosis. Shell patellilbnu, depressed-conical; apex central, perlbrated by
a foramen ; no area or (-inlinid tlattening. Surlace ornamented by concentric
growth-lines bearing spines. Pedicle-valve only known.

Type, Siphonotreta tentorium, Kutorga.

We have elsewhere referred to the fact that this name was provisionally
proposed for a species representing one extreme of variation in the position of
the pedicle-aperture, allowed under Kutorga's diagnosis of the genus Siphono-
treta. Under the original limitations of the latter genus, this form nuist be
excluded as not being congeneric with S. unguiculata. When Mesotreta is bet-
ter known, it may be found to represent an important connecting link between
Acrotreta and Schizambon.

IIU PALEONTOLOGY OF NEW YORK.

Genus S I P H 0 N 0 T R E T A , de Verneuil. 1845.

PLATE IV, FIGS. •24-26, 37, 3S.

1S29. Crania, Eicuwald. Zoologia specialis, vol. i, p. 274.

1840. rtrf6ra/!i/a, Eicuwald. Uebei- das siliiriscli.^Schichten-Syst. von Esthlaml; Journ. Nat. Heil-

kund. ined.-chii-urg-. Acad. St. Petersb., p. 138.
1S42. Terebratula, Eiohwald. Die Urwelt Russlands, Heft 2, p. 145.
1S4.T Siphojwtreta, dk Vkrneuil. In Murchison, de Verneuil and Keyserling's Geol. de la Russie

d'Eurojie et des mont. de I'Oural, p. 286, pi. i, figs. 13, 14.

1848. Siphonotrda (parti'm),KvTon{i!i.. Ueber die BrachiopOden-Familie der Siphonotretasae ; Vei--

handl. i-uss.-kais. mineral. Gesellsch. zu St. Petersburg, p. 261, pis.
vi, vii.

1849. Siplionotreta, Morki.s. AniuaLs of Natural History, Ser. 2, vol. iv, p. 315.

1853. Siplimwtreta, DaviD.son. Introd. British Fossil Brachiopoda, p. 131, pi. ix, tigs. 261-270 (not 268).

1866. Siplionotreta. Davidson. British Silurian Briichiopoda, p. 75, pi viii, figs. 1-6.

1871. Siphonotreta (partim), yuENSTEOT. Petrefaktenkunde Deutschlands; Brachiopoden, p.(>74, pl.lil.

1877. Siphonotreta, Davidson. Geological Magazine, p. 18.

1883. Siplionotreta, Davidso.v. British Siluiian Brachiopoda, Suppl., p. 217, pi. xvi, hg.«. 31-33.

Diagnosis. Sliell elongate-oval, inequivalve ; valves iiiarticulated. Pedicle-
vralve the more convex, with a straight, elevated, conical, and perforated beak,
the circular foramen opening at the apex and communicating with the interior
of the .shell by a tubular canal, which narrows slightly as it passes inward. No
cardinal area or deltidium is present, the growth-lines passing between the beak
and the posterior margin as elsewhere on the shell. Brachial valve depressed-
convex; beak marginal; posterior margin regularly arched and thickened.
Interior of pedicle-valve with muscular impressions confined to the umbonal
region. Close alongside the opening of the sipho, just within the cardinal
margin, lie two elongate scars which are accompanied on either side by broader,
somewhat expanded or tlabellate, simple and less distinct impressions. Directly
in front of the middle pair lies a small central scar, in the axis of the shell,
and at either side of it a transversely elongate impression. These latter im-
pressions are distinctly separated from the former by a transverse ridge.

In the brachial valve the impressions are ecpially concentrated, the entire
muscular area being bounded on its posterior margin by a prominent ridge
which, at the sides, merges into a compound lateral scar. The central portion
of the area is nmch depres.sed and is divided axially by a narrow ridge or
septum.

BRACHIOPODA. Ill

Shell ornamcntod with concentric lines and rid<;es, the epidernia! layer
bearing hollow spines, which are distended at the base. Shell-substance cal-
careo-corneons, the laj^ers beneath tlie epidermis being punctured by radiating
and branching tubules. These layers are concentric and not parallel to the
internal surface.

Type, Siphonotreta unguiculata, Eichwald.

Observations. The foregoing description, with some essential modifications,
is derived from the diagnosis of Sipuonotketa, as given by de Verneuil,
KuTORGA and Davidson. The term as used \iy these writers, especially by
KuTORGA, has been allowed to include species which differ considerably in the
position and structure of that feature of first importance, the pedicle-aperture,
and these forms, under a proper conception of congeneric characters, it seems
advisable to withdraw from the genus.

In Kutorga's elaborate study of Siimionotiikta and its allied genera,* the
position of tiie siphonal opening was considered as var^'ing between the cardi-
nal margin and the center of tiio valve. Strictly, however, the opening takes
neither of these extreme positions in Siphonotreta, for in no species known is
the umbo of the pedicle-valve marginal, and therefore the aperture, which may
be regarded as always truncating the beak, can not be marginal. For the spec-
ies Siphonotreta tentorium, Kutorga, in wliich both apex and aperture are at the
center of the valve, the author himself suggested the name Mesotreta, and the
term may be useful as designating a form intermediate between Acrotreta and
Siphonotreta. Under the discussion of the genus SchizaiMison, reasons are given
for provisionally adopting Mr. Walcott's suggestion, that such species as Siphono-
treta fissa, Kutorga, in which the external opening of the siphonal tube is situated
in front of the apex and connected therewith l)y a conspicuous groove, should
not be regarded as congeneric with S. unguiculata and other forms in which
this aperture is circular and apical. Although there is considerable difference
in the size and external expression of the type-species of Scihzambon {S. typicalis,
Walcott,) and the Russian and Canadian representatives of Siphonotreta Jissa, yet

* Uebei- die Biachiopoden-Familic iler Siphonotretjese, p. 261, pis. vi, vii.

112 PALEONTOLOGY OF NEW YORK.

in the absence of an accurate understanding of the internal impressions, there
appears to be no feature of generic value by which they may be separated ; it
must, however, be admitted that the resemblance in general form and propor-
tions of these latter shells to the true Siphonotreta is very close.

The American palaeozoic faunas have yet furnished no thoroughly satisfac-
tory representative of Siphonotreta. Before us are two specimens of a form
allied to, l)ut probably distinct from the Canadian representatives of Schizam-
BON (?), referred to on a following page, which have been collected by Mr.
Charles ScnncHERT and Mr. E. 0. Ulrich, from the Trenton limestone at
Minneapolis, Minnesota. One of these is an exterior mould, the other retains
both valves, though the umbonal portion of the pedicle-valve has been broken,
leaving no indication of the character of its foraminal aperture. The shell differs
somewhat from the Canadian specimens in outline, being broader over the pallial
region; the brachial valve shows a low longitudinal depression, the shell-sub-
stance is very thin, while in the other species referred to it is remarkably thick,
and its lamcllose structure conspicuously developed ; the ornamentation of the
surface consists, not of sharp, concentric lines, broadening to ridges toward the
margin, but of fine, concentric, anastomosing wrinkles, which are interrupted
over the body of the shell by the edges of the spiniferous lamellae ; the spines
are comparatively short and sparse. Though recognizing the difficulties in the
discrimination of species of Sipho.^otreta, we are nevei:theless disposed to
regard the above-mentioned features as of specific value ; and in the absence
of evidence determining the character and position of the pedicle-passage, it
seems judicious to leave the species for the present under the genus Siphono-
treta, with the designation, Siphonotreta Minnesotensis.

The internal features of this genus are not so precisely known as to permit
the satisfactory determination of homologies with other genera. Dr. David-
son's figures of the interiors of both valves of S. unguiculata, published in the
Geological Magazine for 1877, and reproduced upon our Plate IV, differ in some
important particulars from the earlier figures given by Kutorga, essentially in
the absence of the nipple-like swelling in the umbonal region of the pedicle-

BRACHIOPODA. 113

valve, about tlie opening of the siplio. This feature is seen in all of Kutokga's
illustrations of the interior ami internal casts of S. nnguiailata, and would find
an equivalent in the umbonal swelling in Acrotrkta, Acrothelk and Linnars-

SONIA.

Of the muscular scars in this valve, the anterior probably represents the
anterior adductors, and the long impressions on either side of the sipho, termi-
nating in these anterior scars may be the progressive track left by them in the
growth of the shell. In the opposite valve, Davidson represents a transverse
posterior ridge, suggestive of the crescent in Trimerella, enveloping or ending
in distinct terminal scars, in front of which follow composite laterals divided
by a median ridge. Kutorga's figures show a slight median septum separated
by a furrow on either side from strong diverging ridges ; features which are
not widely different from the impressions in the corresponding valve of LiN-
narssonia.

The Russian species of Siphonotreta {S. ungukulata, Eichwald, S. fornicata,
Kutorga, S. verrucosa, Verneuil, S. aculeala, Kutorga, and (?) S. conoides, Kutorga),
are from the Lower Silurian faunas of the Baltic provinces; S. micula, McCoy,
S. Scoiica, Davidson, are from the Llandeilo flags, while the latest known repre-
sentative of the genus, S. anglica, Morris, is from the Wenlock.

Genus SCHIZAMBON, Walcott. 1884.

PLATE IV, FIGS. 27-30, compark FIGS. 31-36.

1884. iSdiizavibo/i, Walcott. Moiiog-rinihs U. S. Geological Survey, vol. viii ; PjiliEontology of the

Eureka District ot Nevailji, ii. (iO, ])1. i, tij,'. H.
Compare ;
1848. Siplumotreta, KuTOR(i.\. Verhamll. i-uss.-kais. mineral. Gesellsi-h. zu St. Petei'sliiirf,'. .lalirji;-.

1847. p. 271. pi. vii, tig-. 5.
IS.iS. Siphmwtreta, David.so.v. Introii. British Fossil Brachiopoila. pi. ix, ti":. 268.
1883. Siphwiotreta, WHrrEAVus. Amcr. Assoc. Advanc. Science, Monln^al Meetiiifr.
1883. iSiphonotrefa, Davidson. British Sikii-ian Brachiopoila, Sui)plemeiit, p. 218.
1887. >^ip!iniinfi-etn, Ainr. Ottawa (Canaila) Naturalist. Doccinlx-i-.

Diagnosis. " Shell ovate or oblong-oval, inequivalve ; valves inarticulate;
larger or ventral valve most convex, with a short obtuse beak at the cardinal
margin. Foramen oblong, and opening on the suininit of the valve ; no area or
deltidium ; cardinal edge tliin ; smaller or dorsal valve nearly as convex as the

114 PALEONTOLOGY OF NEW YORK.

larger, slightly flattened along the median line. Structure calcareo-corneous,
consisting of a nacreous outer layer with a closely attached inner calcareous
layer. Both layers are thought to be punctured by scattered tubulag. Surface
smooth or with distinct lines of growth, and scattered spines apparently on the
outer edges of the lamin* or lines of growth. The interior of the larger valve
shows the oblong foramen in a slight elongate depression and a pair of muscular
scars just in front of it on each side of a slight longitudinal depression; from
near the beak on each side of the foramen a shallow, sharply defined depres-
sion extends obliquely outward. No other markings were observed. In the
interior of the dorsal valve a pair of anterior central muscular scars terminate
their path of advance from the beak, a slight rounded ridge rising on the
central line ; posterior to these a larger pair occur, and still beyond and more
posterior a third pair; a narrow rounded ridge extending obliquely down from
the beak on each side between the central and lateral scars." (Walcott,
loc. cit.)

Type, Schizambon typicalis, Walcott.

Observations. This peculiar genus presents an additional phase in the
variation in position of the pedicle-aperture. We have seen, in Kutorgina,
AcROTHELE, AcROTRETA, etc, the stages of transition from the marginal pedicle-
slit of the obolelloids to the apical aperture in Siphonotreta, a group in which
the subapical area loses its specilization and the progressive pedicle-furrow or
ridge. Schizambon has the foramen in front of the umbo,
and by the advancing growth of the shell, the opening
always remaining at the same relative distance from the
margin, an external groove, tapering toward the beak, i^
left behind it. The affinity of this genus with Siphono-
treta is very close. In the type-species, the outline and
contour is slightly different from that usually met with in
Siphonotreta, but the surlace is minutely spmiferous, ahm w miott.

while in Siphonotreta fissa, Kutorga,, which Mr. Walcott is vaue.

disposed to regard as congeneric with Schizambon typicalis, the similarity with
typical forms of Siphonotreta, in all external respects save the character of
the pedicle-channel, is complete.

BRACHIOPODA. 115

We have before us an excellent series of specimens representing a species
which has l)oen described as Siphonotreta, from dark limestones intercalated
between shales at Gloucester, Ontario ; beds referred to the age of the
Utica slate of New York. The first mention of these fossils was by Mr. J. F.
Whiteaves, in a paper read before the Montreal meeting of the American
Association for the Advancement of Science, in 1H83; subsequently a more
detailed account of their occurrence and association was given by Mr. H. M Ami,
in the Ottawa Naturalist for December, 1887. To these gentlemen we are
indebted for the opportunity of stud\-ing the fossils. Mr. D.avidson, who ex-
arained the Canadian specimens sent him by Mr. Whiteaves, identified
them with his species Siphonotreta Scotica* but certain differences indicated by
Mr. Ami induced the latter to propose therefor the varietal term Canadensis.

The general features of these specimens and the numerous fine, smooth
spines, indicate a close similarity to Davidson's species ; but in the material
received from Mr. Ami are two pedicle-valves, one of which, shows the ex-
terior character of the pedicle-passage, and the other somewhat of its internal
extension. The former shows this passage to be of precisely the character of
that seen in Kutorga's S. fissa (see Plate IV, figs. 31, ;^3), and the latter (idem,
fig. o4) demonstrates that the interior extension of the sipho was carried as
far forward as the center of the shell.f

Upon comparison of these specimens with Kutorga's description of S. fissa,
we find an agreement in almost every particular ; the .shell has the " depressed
Terebratula-like form" in distinction from other species of the genus; the
striae of growth, fine and sharp about the apex, become broad and thick toward
the margins ; the spaces between the rows of spines are smooth or crossed by
extremely faint radiating lines ; added to this is the character of the pedicle-
groove, its floor being crossed by fine, successive growth-lines. Oidy in the
relative number of the surface spines does there appear any difference.
In the Rus.sian species these are described as a mass of smooth, hair-like

* Silurian Supplement, p. 218. 1883.

f Mr. Davidson described his Scottish species .IS having :iu '-acuminated beak, perforated at its ex-
tremity by a small circular foi-aminal aperture " (Geol. Ma^., 1S77. p. 13). It is therefoi-e evident that the
Canadian species is widely different from S. Scotica.

116 PALEONTOLOGY OF NEW YORK.

spines, with somewhat thicker ones scattered among them; in the American
specimens the spines, also smootli, are all of about the same size on any given
p-rowth-line, increasing somewhat in length from apex to margin. While this
difference in the character of the ornamentation of the surface is apparently so
considerable we should hesitate to regard the Russian and American forms as
identical. At all events a change of name for the American species is required,
and it is proposed to designate it Schizambon? Canadensis, Ami.

In allocating these Canadian forms and Kutorga's S. fissa, tentatively with
the genus Schizambon, it is important not to lose sight of certain apparent
differences in the structure of the pedicle-passage. In all the specimens of
Schizambon typicalis which we have examined, this passage appears to be a
simple oval slit, transecting the shell almost vertically, without forming the
short internal tube evident in the Canadian examples. The same character is
shown in Mr. Walcott's figures. The shells of S. typicalis are, however, tenu-
ous and this divergence may prove to be entirely fortuitous and due to the
imperfect retention of the original characters. It is with this reservation in
mind that the Canadian specimens are referred to Schizambon.

The formation of the foraminal groove in all these species is undoubtedly to
be regarded as the progressive track of the pedicle-aperture, indicating its suc-
cessive positions in different stages of growth.

The agreement in the external character of the pedicle-passage in Schizam-
bon and ScHizoTKETA {Orbiculoidea conica, D wight, 0. Forbesi, Davidson), is very
striking; indeed specimens of the pedicle-valve of Professor Dwight's species,
in which the apex of the shell is distinctly turned toward the anterior margin,
have a resemblance to the corresponding valve in Schizambon? fissus. The in-
terior extension of the passage in the two genera is different; in the latter
(Schizambon), a tube ending abruptly in about the center of the shell ; in the
former the passage is not tubular, except where transecting the shell, or when
enveloped by internal callosities, (See the discussion of these characters under
genus Orbiculoidka.)

With regard to the internal markings of these fossils, it is difficult to detect
features susceptible of a satisfactory interpretation. Specimens of the type-

BRACHIOPODA. I J 7

species have been kindly placed at our disposal by Mr. Walcott, and the
representations of the interior of both valves given upon Plate IV show the
muscular impressions as clearly as we have been able to make them out, and
are in essential agreement with Mr. Walcott's conception of them. The in-
terior of the pedicle-valve shows a broad, low sinus with its slightly elevated
margins diverging outward from the foramen. Two lateral diverging ridges
also take their origin near the beak, while the track of the pedicle-aperture is
marked on this surface by a low axial incision. In the opposite valve is a low
median ridge with two or more pairs of diverging lateral ridges, the outer
of which is the stronger. The extremities of the intermediate ridges fre-
quently show a subcircular discoloration, which may indicate the last implanta-
tion of the lateral muscular bands. The whole muscular area appears somewhat
thickened and elevated. In S. ? Canadensis, we have found only evidence of a
strong median septum.

Schizambon typicalis appears to l)e the earliest representative of this group,
being from the lower part of the " Pogonip group " of Mr. Walcott, or the
lowest Silurian (Primordial?) of the Eureka District, Nevada. It is therefore
the predecessor of the other members of the genus, wdiich are from the later
faunas of the Lower Silurian; a fact which may account for the divergence of
the latter, in some respects, from the type-species.

Genus KEYSERLINGIA, P.vndkr. 1861.

PI- ATE IV, FIUS. 1-:!.

18G1. Keyserlitigia, Pander. Ball, de l'Ac,:i<i. Imp. des Sciences de St. PiStersbotii-g:, vol. iii, p. 4G, pi.
ii, fig-. \a-h\ in llclnierscn's " Die geolog. Beschiitrenh. d. unt. Narovatlials," etc.

Diagnosis. " Shell inequivalve, subcircular or oval. Ventral valve more or
less conical, with a prominent apex which is sometimes near, sometimes distant
from the cardinal margin. From this apex diverge posteriorly two low ridges
enclosing a flattened triangular area, which is divided in the center by a vertical
fissure. The lines of growth cross the hinge-line, forming in the center a
faintly depressed triangular groove, as in Hclmersknia and Obolus. In the
interior of the valve a closed tube is continued i'roni the external fissure, in the

118 PALAEONTOLOGY OF NEW YORK.

axial line. The first one-third of this tnbe is swollen and thickened, but
thenceforward it passes, with parallel edges, to the anterior margins, where it
is probably closed, though usually broken. Dorsal valve more depressed, its
greatest convexity being in the center. Cardinal area as in the opposite valve,
but narrower. A closed tube, beginning in a swelling just in front of the car-
dinal line, is continued [from the center of the shell] to the anterior margin
as an open channel. Muscular scars as in Obolus and Helmersenia, but more
sharply defined." (Pander, he. cit.)

Type, Orbicula Buchi, Verneuil. 1845. Grol. de la Russ-. de I'Europe et des
mont. d'Oural, p. 288, pi. xix, figs. 1 a, b, c.

This most peculiar genus presents a close alliance in its muscular impressions
to Obolus, perhaps more nearly to the Neobolus of Waagen, but in its interior
closed tubes, that of the pedicle-valve communicating with the external fissure,
its relationship to the Siphonotretids is demonstrated. Too little is known of
the permanent characters of the fossil to form any reliable conclusions in regard
to its proper association, but from the foregoing description it would appear to
present the anomalous character of a Siphonotretid in which the pedicle-tube
is in a condition of atrophy, compelling the pedicle to pass between the
valves, over the cardinal area, as in Obolus. The presence of a caecal tube in
each valve, if ever devoted to the passage of the pedicle, is altogether un-
precedented.

In regard to the propriety of the generic term Keyserlingia, it may be
observed that although Pander's description and illustration are given without
specification of the typical species, the genus was founded on the " Orbicula,
Murch., Vern,, Keys. Geol. de la Rus.sie, 1845, vol. ii, pag. 288," i. e., Orbicula
Buchi, not 0. reversa, Vern., which has been quoted by Dall* as the type-spec-
ies, but which is described on page 289 of that work. The genus Orbicella,
D'Orbigny, 1847, was evidently founded to include the class of shells for which
Sharpe, in the same year, proposed the name Trematis. It does not appear,
however, that any example was cited with the first use of this term in the

'■ Biillt-tiii No. S, U. S. National Museum, p. 39. 1877.

BRACHIOPODA. 119

Comptes rendus,* but in 1849,f in giving a list of species referable to tlie genus,
the first mentioned is Orbicula Buchi, Verneuil, and it seems that this must be
taken as the type of the genus Oubicella. Under the rigid enforcement of the
current rules for the recognition of pi'iority of nomenclature, Kkyserlixgia
becomes a synonym for Orbicella, D'Orbigny, although this construction of
the matter does no justice to the intentions of the autliors of either generic
term.

Genus HELMERSENIA, Pander. 1861.

PLATE IV, FIGS. i-o.

18G1. Hehnersenia, Pander. Bull, de I'Acad. Imp. ties Sciences de St. PcU!i-.-;boui-g-, vol. iii, p. 47, pi.

ii, tig. 2, a-g.

Diagnosis. Shell having the general form of Obolus, with a prominent car-
dinal area depressed in the center by a broad, low pedicle-groove (?). Apex of
the ventral valve truncated by a circular hole, which is not j^roduced into an
internal tube. Muscular impressions indistinct. No specific name has been
proposed for the typical form.

Like the foregoing, this genus shows, in its csecal (?) apical tube and oboloid
cardinal area, characters all3dng it to both Siphoxotreta and Obolus, and, like
Keyserlingia, also needs a verification of its peculiar features before its proper
relationship can be demonstrated.

* Vol. XXV, p. 269.

t Prodrome de Paleont. Stratigraphique, p. 20

120 PALEONTOLOGY OF NEW YORK.

Genera DISC IN A, Lamarck, 1819; ORBICULA, Sowerby, 1822;
ORBICULOIDEA, D'Orbignv, 1847; SCHIZOTRETA, Kutorga,
1848; ORBICULOIDEA, Davidson, 1856; D I S C I N I S C A, Dall,
1871 ; L I N D S T R CE M E L L A , sub-gen. nov. ; CEHLERTELLA,
SUB-GEN. NOV. ; RCEMERELLA, sub-gen. nov. ; D I S C I N A , of
authors generally.

I'LATE IV E, FIGS. 1-31 ; PLATE IV F, FIGS. 1-3J ; PLATE IV K, FIGS. 4,23,24.

1842. Orbicula, Vanoxbm. Geology of New York ; Report Third District.

1843. Orbicula, Hall. Geology of New York ; Report Fourth District.
1847. Orbicula, Hall. P;ilaeonto!ogy of New Y'ork, vol. i.

1852. Orbicula, Hall. Paleontology of New Y'ork, vol. ii.

1858. Disnna, Shdmakd. Tians. St. Louis Academy of Science.

1859. Dhcina, Meek and Harden. Proceedings Philadelphia Academy Natural Science.

1859. Discina, Hall. PaliBontnlogy of New Y'ork, vol. iii.
1S60. Discina, Shdmard. Trans. St. Louis Academy of Science.

1860. Discina, Hall. Thirteenth Rept. N. Y*. State Cab. Nat. History.

1860. Dixcina, Hall. Canadian Naturalist and Geologist.

1861. Discina, Shdmard. American Joui-nal of Science.

1862. Discina, Billings. Palseozoic Fossils, vol. i.

1862. Discina, Hall. Fifteenth Rept. N. Y. State Cal). Nat. History.

1862. Discina, White. Proceedings Bostcm Society Natural History.

lS6a. Discina, Hall. Sixteenth Rept. N. Y. State Cab. N.at. History.

1865. Discina, A. Winchell. Proceedings Philadelphia Academy Natui-al Science.

1865. Discina, McChesnby. Trans. Chicago Academy Sciences.

1867. Discina, Hall. Pala;ontology of New Y'ork, vol. iv.

1868. Discina, Hartt. Dawson's Acadian Geology.

1870. D'lscina, A. Winchell. Proceedings American Philosophical Society, vol. xii.

1872. Discina {Orbicaloideai), Hall and Whitfield. Twenty-fourth Rept. N. Y. State Mus. Nat. Hist.

1872. OrUculoidea, Meek. Rept. Palseoiitology Eastern Nebraska.

1873. D'mriiui, Meek and Worthb.v. Geological Survey of Illinois, vol. v.

1873. Orbiculoidea, Hall. Twenty-third Rept. N. Y. State Cab. Nat. History.

1874. Discina, Rathbdn. Bulletin Buffalo Society Natural History.

1874. Discina, Derby. Bulletin Cornell University, vol. i. No. 2.

1875. Discina (Orbiculoideaf), Hall and Whitfield. Twenty-seveutli Rept. N. Y. State Mus. Nat.

History.

1875. D'lscina [Orbiculoidea), Meek. Geological Survey of Ohio ; PalfBontology, vol. ii.

1875. Discina, Nichomon. Rept. Palaeontology Province Ontario.

1878. D'lscina, Ulricu. Joui-nal Cincinnati Society Natural Histoi-y.

1878. Discina, Barrel'. Ann. New Y'ork Academy of Sciences.

1878. Discina, Ratubux. Proceedings Bo.ston Society Natural History.

1878. Discina, Rathbu.v. Bulletin Buffalo Society Natural History.

1878. DisciJia, Daw.so.v. Acadian Geology, Third Editicm.

1880. Discina. Whitfibld. Annual Report Geological Survey of Wisconsin.

1882. Disdiia, Whitfield. Descriptions of New Species of Fossils from Ohio.

1882. Discina, Whitfield. Geology Wisconsin, vol. iv, pt. 3, Paleontology.

1882. Discina, Ringdebekg. Amei-ican Naturalist, Septembei-.

BRACmOPODA. 121

1884. Discina, Worthen. Bulletin No. 2. Illinois State Museum Natural History.

1884. Discina, White. Thirteenth Ann. Rept. State Geologist Imiiana.

1884. Discina, Walcott. PaliEontolog-y Eureka District.

1885. Discina, Clarke. Bull. No. IG, U. S. Geological Survey.
188S. Orbiculoidea, Herrick. Bull. Denison Univei-sity, vol. iv.

From the lack of proper apprehension ol' the type-species of the genera
Discina, Orbicula and Orbiculoidea, there has long been, and .still exists great
confusion among authors in the application of these terms. The zealous
endeavors of Mr. AY. H. Dall* to unravel the complications in which these
genera are involved, and to clear away the uncertainty in regard to the specific
values of the types, ought to go far toward removing the general reluctance to dis-
turb the currency of some of these terms, especialh^ Discina, a name in almost
universal use for forms confessedly not congeneric. The rectifications required
in such a case as this are of so fundamental a nature as to cause a certain
disquietude, but such instances serve to emphasize the necessity for the enforce-
ment of the rule too often violated, that the application of a generic name
must be in harmony with the characters of the type-species.

The genus Discina was described by Lamarck in lS19,f and the typical
example taken, D. ostrceoides, Lamarck, of which neither figure nor description
was given. It appears from observations by Reeve,! that the originsil specimen
used by Lamarck was obtained from Mr. J. de C. Sowerbv, and Dall observes§
that it " is the same species and from the same lot of specimens, as the shell
described by Mr. G. B. Sowerby in the Linnean Transactions, and well figured
by him there under the name of Orbicula Norvegica. His very excellent figure
enables me to speak with positiveness in saying that it is identical with Crania
radiosa, Gould, of which the type-specimens are before me. The figures of
Schumacher are sufficiently exact to allow of identifying the species with his
[Schumacher's] Crania striata." But this Orbicula Norvegica of Sowebby|| is

*Bull. Museum Comparative Zoology, Harvard College, vol. iii, No. 1. 1--71.
t Histoire Naturelle des Animaux sans vertebres, vol. vi, p. 236.

I Conchologia Iconica; Mongi-. genus Orbicula. 1862. See, also, Revision of the History, Synonymy,
and Geographical Distribution of the recent Crania and Orljiculae, in Ann. Nat. Hist., vol. x. 1'^''2.
§ Bull. Museum Comparative Zoology, loc. cit., p. 40.
1 Trans. Linnean Society, vol. xiii, ji. 46S. 1822.

122 PALjEONTOLOGY OF NEW YORK.

not the Orbicula Norvegica of Lamarck * the Lamarckian species having proven
identical witli the Patella anomala of Mcller.j This latter species, however, is a
Crania ; and as the 0. Norvegica, Lamarck, was taken as the type-species of
Cuvier's genus Orbicula, the genus Orbicula, in its Cuvierian sense, becomes
a synonym for Crania. This fact of synonymy was pointed out by Dr. J. E.
Grav, as long ago as 182o,| but the genus Orbicula had become so thoroughly
confounded by authors with Disgina that, to avoid a disturbance of nomenclature,
the name was retained by Mr. Davidson§ and Professor Hall,|| as late as 1852,
for the DisciNA of authors, not of Lamarck.

Li 1854, Mr. Davidson^ considered the Discina ostraoides, Lamarck, as iden-
tical with D. lamdlosa, Broderip, 1833,** and therefore, in the absence of a
description of D. ostraoides, assumed the latter as the tyj^e-species. This assump-
tion must now be regarded as inadmissible, and was abandoned by Mr. Davidson
in his "General Summary" (1884) and "Monograph of Recent Brachiopoda"
(1888).ff In accordance with Dall's observations, we are compelled to accept Dis-
cina striata, Schumacher {Crania striata, Schumacher, Essai d'un nouveau systeme
des habitudes des Vers Testacrs, p. 102, pi. xx, figs. 1 a-f, 1817, == Orbicula
Norvegica, ^owerhy, 1822, not Lamarck, \%'d\, = Discina ostrceoides, Lamarck,
ISl'.i), as the typical species of the genus. This species is not to be confounded
with the Discina striata, Sowerby,|:]: which is a Silurian (Ludlow) form, while
Schumacher's species, the designation of which antedates that of Sowerby, is
recent and of West African habitat.

The diagnosis of the genus Discina, as derived from the species D. striata,
Schumacher, is given by Dall in the following terms:

" Sub-genus Discina (Lam.), Dall. Shell of rather solid texture, with a con-

* Sy.st. Nat, p. 140. 1801 ; and Hist. Animaux sans vei-tfeb., Ed. I, vol. vi, p. 242. 1819; Ed. 11, vol.
vii, p. 316. 1836.

t Zoologiaj DaniciE Prodi-omus, p. 237. 177G.
I Annals of Philosophy, Now Sorio.s, vol. x. p. 244.
§ Tertiary Brachiojioila.
1 Palajontology N. Y., vol.' ii.
*i] Introil. Brit. Foss. Brach.
** Proc. Zool. Soc, vol. i, pp. 124, 125.

tt Trans. Linnean Society, Second Series, Zoolog-y, vol. iv, pt. 3.
tt Sil. Sj'st., 111. V, fig-. 21. 1839, and Davidson, Silur. Brach., p. 07, pi. vi. li^'s. 1-4.

BRACHIOPODA. 123

sidenible amount of calcareous matter in it; no signs of punctation to be seen
with a half-inch objective. Valves convex, the lower valve varying in amount
of convexity with its habitat, but always more or less inllated. A small, sharp,
longitudinal septum rises from the center of the lower valve, of a subtriangular
shape, covering and hiding a small tubular perforation of the apex of the shell.
This perforation is very oblique, and from its internal opening a groove extends
backward nearly half-waj^ to the posterior l^order of tlie sliell inside. The an-
terior muscular scars meet in front of the septum and Ibrm a semilunar eleva-
tion with the points directed backward. The posterior scars in the lower valve
are small and widely separated. On the external surface the foramen appears
nearly in the middle of the shell and the furrow is continued anteriorly for a
short distance. (There is no furrow in my specimens outside behind the fora-
men, which is the only point of difference from Sowerby's figure.) Upper
valve convex, apex subcentral ; a slight median longitudinal callus internally.
There is no strongly impressed disc about the foramen as in Discinisca, though
slight traces of a differentiated area exist there."*

Discina striata, Schumacher, is the only known representative of this genus.
(See Plate IV k, figs. 23, 24.) Its minute, almost imperceptible foramen (so
small that both Schumacher and Gould, not seeing it, referred the species to
Crania), and the arrangement of its internal impressions, separate it by a full
generic difference from its nearest allies. With Discina, therefore, we have at
present nothing to do among the palaeozoic brachiopods.

The foregoing limitation of the genus Discina by Mr. Dall left all the other
recent species, currently referred to that group, without a designation, and for
these the author proposed the term Discinisca, witli the following definition :f

"Sub-genus Discinisca, Dall,= Discina, Auct. Lower valve more or less
flattened, concave or compressed, Upper valve more convex ; apices of both
subcentral or subposterior. Lower valve with a snudl septum as in Discina,
behind which is an impressed disc or area, externally concave and internally
elevated. This is perforated by a longitudinal fissure, extending from a short
distance behind the septum nearly to the posterior margin, which is often
slightly indented behind it. Shell more or less horny in texture, minutely
tubulose. Type, Discina lamellosa, Broderip."J

* Bull. Mus. Comp. Zool., vol. viii, No. 1, p. 3S).
t Bull. Mus. Oomp. Zool., vol. iii, No. 1, p. 37.
I Proc. Zool.. See, 1833, p. 124.

124 PALEONTOLOGY OF NEW YORK.

The character of most emphatic importance in this group is the broad, ele-
vated, internal pedicle-disc with thickened lateral margins, but with a thin,
tenuous central area, perforated by an oval slit passing directly, not obliquely,
through the substance of the area. On the outer surface of the shell this disc
is much depressed, interrupting for its entire width the concentric growth-lines,
and showing upon its surface only the progressive track of the foramen as it
has become closed in its advance from the apex toward the posterior margin
with the growth of the shell.

When we turn to the consideration of the generic value of palaeozoic fossils,
passing current under the name Discina, we are met by two serious obstacles :
(1) it is rarely that these fossils are preserved so as to show the exact character
of the foraminal aperture and area, this condition, no doubt, being largely due
to the extreme, often membranous tenuity of the parts immediately surround-
ing the aperture, and the ease with which the projecting portions of the area are
broken ; (2) the illustrations of these fossils which have been given by authors
are, as a rule, drawn on so small a scale, or from such unsatisfactory specimens
that it is impossible to form an accurate idea of the character of the aperture
and disc. Notable exceptions to this general statement will presently be
cited.

ZiTTEL,* recognizing the three divisions, Discina, Orbiculoidea and Discinisca,
as sub-genera of Discina, Lamarck {i. e. {!), the current interpretation of Dis-
cina, Lamarck), is authority for the statement that the genus Discinisca ranges
from the Silurian faunas to the recent. Personally, we have no knowledge of
any palaeozoic species showing the elevated disc and vertical slit characterizing
Discinisca, and are not aware that any author has described and figured a
palseozoic species which can be safely referred to this genus.

We have before us a very large amount of material representing the palaeozoic
" Discinas," which has been carefully selected for the purpose of studying the
variations in. the characters of the pedicle-groove and disc. Among the species
well represented are Orbiculoidea conica,D wight, from the Trenton, D. tenuilamel-

* Handbuch der Palaontologie, vol. i, p. 667. 1880.

BRACHIOPODA.

125

lata, Hall {^Orbiculoidea Forbesi, Nicholson (not Davidson)=Z). clara, Spencer,^
D.so/iterm, Ringueberg), from the Niagara, D.Conradi, Hall, and D. discus, Hall,
from the Lower Helderberg, D ampla, Hall, from the Oriskany sandstone, D.
minuta. Hall, from the Marcellus shales, D. media. Hall, D. grandis, Vanuxem, D.
humilis. Hall, D. Randalli, Hall, D. Doric, Hall, D. marginalis, Whitfield, from the
Hamilton group, D. Lodensis, Vanuxem, from the Genesee shales, D. pleurites,
Meek, from the Waverly, D. Newberryi, Hall, from the Cuyahoga shales, D. nitida,
Phillips, D. Manhattanensis, Meek and Hayden, Iroui the Coal Measures, and
man}^ additional species, with several unidentified, probably undescribed forms
from vax'ious horizons.

The pedicle-perforation in these fossils is not, as usually represented, a simple,
elongate fissure, extending from I)eneath the apex, one-third, one-half or the
entire distance to the posterior margin. On the contrary, just behind the apex,
and removed from it by a distance varying with the stage of growth of the
animal, is the external opening of a perforation, which passes very obliquely
backward through the substance of the shell and opens on the interior surface
not far from, but within the margin of the shell, having thus precisely the re-

FiG. ti^. Vertical section of ihe itodiolc-
valve of Discina striata.
After Davidson.

Fig. (U. Vertical sectiou of tiie pcflicle-
valve of Orbiculoid&r.

verse position to that of Discina striata as given by Davidson,* whose figure is
here copied, but very much greater obliquity.

On the external surface of the pedicle-valve, the pedicle-groove, which begins
at the apex, intersects more or less abruptly the usual concentric ornamenta-
tion of the shell, but it is very narrow, ami its surface generally smooth or
with tnint indications of growth-lines. In all instances this furrow begins at
the apex; its length, however, in any given species, will, as just noticed, depend
on tiie stage of growth, for the pedicle-aperture evidently keeps the same rela-
tive distance from the apex in all periods of development. This portion of the

* Trans. Linne.an Soc, vol. iv. pt. 1, pi. 26, fig. 26. ISSS.

126 PALEONTOLOGY OF NEW YORK.

pedicle-groove may then be regarded as the track left by the advance of the ex-
ternal opening of tlie foramen, closed by later testaceous secretions and quite
homologous to the anterior portion of the great depression surrounding the pedicle-
slit in DisciNiscA. In certain thick-shelled species, like Orbiciiloidea conica and 0.
Forbesi (to which reference will again be nuide under the discussion of the genus
ScmzoTRETA, Kutorga), the evidence of the external furrow ends abruptly with
the disappearance of the pedicle-groove into the substance of the valve. In
general, however, the shell of paliBozoic " Discinas " is very tenuous, and their
compression in the process of fossilization often confounds the features of the
inner and outer surfaces of the pedicle-area, making them appear continuous.
It seems evident that in these fossils the groove upon the external surface is,
as a rule, of essentially the same character as that seen in Davidson's figures
of Orbiculoidea Forbesi* Dwight's figures of 0. co7iica,-\ and those of the latter
species given oh Plate IV f of this volume ; outside the foramen the concentric
lines following without interruption, as on any other portion of the external
surface.

On the internal surface of the pedicle-valve the track of the pedicle-groove
extends along nearly the entire radius of the shell. In no species have we
found the internal character of this feature so well retained, and showing so
clearly the changes passed through from youth to maturity as in an undescribed
species,! from the Cuyahoga shales at Berea, Ohio, and in D. nitida from the
shales of the lower Coal Measures, at Springfield, Illinois. The specimens
from these formations frequently preserve the test without mutilation or mucli
distortion. Early in tlie life of these species the foramen has penetrated the
internal surface near the apex, and whatever groove has been made upon the
outer surface by the radial progress of the foraminal aperture is also marked on
the inner side, and is usually somewhat calloused, conspicuously so in adult

* Silurian Brachiopoda, pi. xii, figs. 14, 14 b, 15, IS.

t Amei-ican .Joiinial of Science, 1880, pi. xxi, figs. 1-5.

I This sj)ecies has come to us fi'om various quarters labelled " Diseina Newbm-ryi, Hall." With the
latter however it does not agree, the pedicle-area not being- elevated nor so broad as in that species, and
the brachial valve rather more convex with its apex nearer the center. The original specimens of D. iVfW-
ben-yi are from a I'errng-inons sandstone, 110 IXh-X below the conglornei-ate at Cnyahoga Falls ; those of the
species in question, which may be tei-med Orbicidoklea Hevzeri, from greenish-black shales at Berea, Ohio.

BRACHIOPODA. 127

specimens. Tlie passage for the pedicle is so oblique to the planes of the sur-
faces of the valve that its inner termination is not abrupt but commonly pro-
duced into a fine groove, visible over nearU' or fully the distal half the length
of the pedicle-area and sometimes traceable even to the margin of the shell.
Contemporaneous with the growth of the shell is the development of a callosity
close about the margins of this groove, which often becomes so high as not only
to have deepened the passage, but in advanced age to have wholly enveloped it,
the two callosities becoming coalesced and leaving an opening for the pedicle
only at their posterior extremity. (See Plate IVf, figs. 8-17.) This callosity
is developed with substantial symmetry in D. Herzeri (see foot-note on preced-
ing page), D. marginalis, D. ampla, etc., occasionally showing a tendency to
irregular, though not unsynnnetrical growth. In many species it never attains
a great development, being scared}' more than a linear elevation or a narrow
ridge, bordering and partially or wholly enveloping the pedicle-groove ; the
adult condition in such species being essentially identical in this respect to the
earlier stages of growth in those where the callosity eventually closes all but the
aperture of the foramen. In Orbiculoidea tenuilamellala, we find the internal
character of the pedicle-area of precisely the same nature. On the inside no
indication is given of the length of the external groove, l)ut the inner callosity
extends from the apex almost, if not, in some instances, (juite to the posterior
margin, without leaving any trace upon the external surface, when the shell
is uncompressed.

So far as we are aware the features described above have been rarely illus-
trated by any author. Barrande has given* illustrations of the e.\terior and
interior of his species, D. Bohemica, the former showing the short external groove,
and the latter the inner prolongation of the groove or ridge to the margin.
The same features may be seen in his figures of D. Maotis.j Attention may
also be directed to Mr. Davidson's figure of D. nitida,t which shows very
distinctly from the interior the floor of the long pedicle-groove and the inner
opening of the foramen ; and to Mr. Meek's figure of Orbiculoidea, sp. ?, in

* Sysfdme Silurien liu Centre de la Buheme, vol. v, pi. 97, liy. v, 1 A, 2 a.
t Systeme Silurien du Centre de la Boheme, vol. v. pi. 100, fig-, ii.
I Permian and Carboniferous Supplement, pi. xxx, fig. 13 a.

128 PALAEONTOLOGY OF NEW YORK.

the Final Report of the United States Geological Survey of Nebraska, and re-
produced upon Plate IV f, fig. 31.

It is now easy to find an explanation of the apparently great variation in the
length of the groove in these fossils. Even in a given species it will appear
sometimes short, at other times seeming to reach nearly or quite to the margin,
according as the specimen shows the outer or the inner surface. Unquestion-
al)ly the length of the external groove is a matter of specific variation to a
slight extent only, its development keeping pace with the age of the shell,
while the length of the internal furrow appears to be, to a much more consider-
able degree, susceptible of variation in a given species.

Leaving the further discussion of the characters of these fossils for subse-
quent reference, we may turn to the consideration of the generic term:

Orbiculoidea, D'Orbigny, 1847. Considerations zoologiques et grologiques
sur les Brachiopodes ; Comptes rendus, vol. xxv, p. 269.

The definition of this term was first given in the Prodrome de palron-
tologie stratigraphique, 1849, and is in the following terms: " Coquille de
contrxture corm'-e non perfon'e, dont la valve inferieure concave est pourvue
d'un ouverture laterale ou crochet pour le passage d'un pedicule simple," the first
example cited under this definition being the Orbicula Morrisi, Davidson. Mr.
Dai.i. has observed* that in neither the first use of the term,f nor in the sec-
ond,J: was an example cited, and, therefore, reaches the unavoidable conclusion
tliat 0. Morrisi, being the first citation made by the author, must be assumed
as the t\-pical species. Mr. Davidson, in lSo3,§ was disposed to consider
Kutroga's genus, Schizotreta, as synonymous with Orbiculoidea, and took
Kutorga's type, S. ellipiica, as the type of the latter genus. Subsequently
(1866), II holding to the equivalence of these terms, he did not modify his
opinion as to the type-species of Orbiculoidea.

* Bulletin No. S, U. S. National Museum, ji. 51. 1877.

t Comptes rendus, vol. xxv, p. 269.

J Ann. Sci. Nat., vol. xxx. p. 351. 1850.

§ Introd. Bi-itish Fossil Bnichiopoda, jip. 12!l-131.

I Silurian Brachiojioila, i)p. 72, 73.

BRACHIOPODA. 120

The Orbicula Morrisi was described by Davidson* in 1848 from iinperlbrate
valves only, and his subsequent noticef of the species (1866) as (?) Discina
Mormi, did not add essentially to the knowledge of its characters. In 185-5, how-
ever, McCoy had noticed! the species as Discina Morrisi, and, without giving any
figures, described the pedicle-valve, from which it would appear that it is de-
pressed-convex, concave about the margins, the " fissure " being " very broad,
oval, half its length from the posterior margin." We are not able to gather
from these meager details, or from any other published description of the species,
the precise character of the foraminal aperture, and having been unable to
obtain suitably preserved specimens of the pedicle-valve, can not directly com-
pare this feature with that of the forms under discussion above. However, the
imperforate valve in the species is strongly convex, witli an excentric, poste-
riorly directed apex, and this fact combined with McCoy's description of the
pedicle-valve, gives to the species a general contour in precise harmony with
that prevailing among the palaeozoic "Discinas" generally, while those species
now passing under the name of Orbicdloide.4, Davidson, are distinctive in hav-
ing the relative convexity of the valves reversed, the pedicle-valve being the
more convex.

This relative convexity of the valves in " Discina," though alwa3's liable
to diminution from compression in fossilization, is a permanent feature, and,
as far as our observations extend, invariabh' associated with the foraminal
characters already described, except in the instances cited below. We there-
fore feel justified in regarding all these species as congeneric (with reservations
in favor of forms of the type of Orbiculoidea conica, 0. Forbesi, etc.), and adopting
for them the terra, Orbiculoide.\, D'Orbigny, not Davidson, = Discin.\ (palae-
ozoic species), of authors.

Diagnosis. Shells subcircular or subelliptical in outline, iuequi valve. Apices
excentric. Pedicle-valve depressed-convex or flattened, with the apex slightly
elevated and inclined posteriorly. On the exterior of the valve a narrow pedi-

* Bull. Snc. Geol. de France, Second Series, vol. v, p. 334. 1848.
t Silurian Brachiopoda, p. 65, pi. vii, figs. 10-12. 1866.
X British Palaeozoic Fossils, p. 190.

130 PALEONTOLOGY OF NEW YORK.

cle-furrow, abruptly intercepting the ornamentation but not penetrating the
substance of the shell, begins just below and behind the apex, extends over a
greater or less portion of the radius of the valve, and, at its distal end, is
produced into a short tubular siplio, which traverses the substance of the shell
obliquely backward, emerging on the interior surface, where it produces a
narrow groove, and usually terminates before reaching the margin of the valve.
On the interior, the position of the external groove is marked by a thickened
ridge extending from the apex, and this is continuous with the thickened mar-
gins of the internal groove, which, in advanced age, may become so developed
as to envelop this groove, except at its outer end.

The larger or brachial valve is depressed-conical, with the apex more
strongly directed backward than in the opposite valve. Tlie interior shows a
fine longitudinal ridge or septum extending from the apex forward. Other-
wise the internal markings are not satisfactorily known.

Shell-substance composed of alternating lamellae of corneous and mineral
matter, the latter often removed in fossilization, making the shell apjiear essen-
tially phosphatic. Surface ornamentation usually consisting of fine, crowded
or distant, sometimes lamellose concentric lines, occasionally crossed by radiat-
ing lines or ridges.

Type, Orbicula Morrisi, Davidson. Wenlock limestone.

Under the above limitations these fossils appear to constitute a very compact
generic group subject to no essential variation. In order to properly interpret
their pedicle-characters as usually preserved, emphasis must again be laid upon
the fact, that, by compression of the tenuous shell, the external and internal
features of the groove are frequently made to appear as continuous, and the
careful observer will seek examples in which the normal contour of the shell
has not been disturbed in fossilization. In some species the external depres-
sion of the pedicle-area is very considerable (D. Newberryi, D. Conradi, D. ampla),
though not of tlie extent seen in Discinisca, nor so greatly thickened ; and
such species often show more distinctly the composition of the base or
Hoor of the groove lying between the apex and the external aperture, a tripartite

BRACHIOPODA. 131

arrangement in which the middle portion represents the path of the aperture.
This character is not only common to palaeozoic "Discinas" generally, but is seen
in ScHizoTRETA, DisciNiscA and Schi/.ocrania. A serious dilliculty may sometimes
arise in the determination of the character of the pedicle-groove outside or
behind the aperture. By examining a specimen of the recent Discinisca lamel-
losa, it will be seen that the callous margins of the groove in tills part of the
shell are connected by only a thin transparent lamella, whicii, if broken, as is
often the case, would leave the valve with a slit extending to the margin, as in
ScHlzocRANiA or Trematis. In the fossils under discussion, there sometimes
appears evidence that the sides of the groove are thus separated and not infre-
quently the pedicle-valve has been so figured, witli a slit extending quite to
the margin.

In certain species we have evidence that in the earlier stages of growth the
pedicle-groove opens upon the margin, its distal edges gradually approaching
as growth advances, until, at maturity, they are united, and with further in-
crease in age, the distance of the groove from the margin is augmented. No
adult example, however, presents any other condition of this part of the shell
than that above described, except when a matter of imperfect preservation.
We have axamined a fragment of bituminous slate, Iroui the lower Coal Measures
at Springfield, Illinois, bearing a great number of individuals of the Z>«cma ?7itida
of Phillips (as identified by the Illinois palaeontologists), in various stages of
growth, from a diameter of .9 mm. to that of 9 mm., the latter being the size of
the average adult. A pedicle-valve .9 mm in diameter, shows that the margins of
the groove, from the beginning of the foramen outward,are(iuite widely separated,
but at a size of 5 mm. they have come into close approximation, without unit-
ing, while an individual of 5.5 mm. diameter has them distinctly united, but
in another, measuring 6.5 mm. diameter, they are still free. Larger examples,
in which the groove is wholly enclosed, bear a linear incision or track of the
groove quite to the margin. The same developmental process appears in Dis-
cina minuta. Hall, of the Marcellus shales, and D. Herbert, of the Cuyahoga
shales, the younger stages of growth showing that the pedicle-groove is open
at the margin.

132 PALEONTOLOGY OF NEW YORK.

We must therefore consider the enclosure of the groove an essentially adult
character of Orbiculoidea, and in cases like that of the genus Tkematis, where
the substantial difference from Orbiculoidea lies in the 2)ersistent ojaen pedicle-
fissure, we may regard the generic distinction as founded not on a genetic, but
rather on a developmental difference, Trematis retaining at maturity a pedicle-
passage having a character, which in Orbiculoidea, is embryonic ; and as far
as these characters alone are concerned, the same is essentially true of Schizo-
crania. There are species passing under the name of Discina, which show such
features as these at maturity; as for example, a form in the Lower Helderberg
commonly referred to the Discina discus, Hall, of which the best specimens
obtainable indicate that the aperture is similar to, but considerably more con-
tracted than in Schizocrania, approaching Trematis in this respect; but the
character of the upper valve, its marginal beak and finely radiated surface, show
further agreement with Schizocrania, and it seems best to remove the species,
provisionally at least, to this genus.*

Again, the Discina pleurites of Meek, from the Waverly sandstones of Ohio,
is a species whose form and contour is precisely that of Schizocrania ; the
upper valve is evenly convex, and has a submarginal beak, but its surface
markings consist wholly of concentric striae. As in Schizocrania, also, attach-
ment is largely eflected by the margin of the upper valve, while the pedicle-
passage is an open fissure extending from the termination of the floor of the
groove to the margin, where it is somewhat constricted, as in Trematis ; at the
same time the floor of the pedicle-groove partakes of the tripartite structure
seen in all these genera. The entire pedicle-area is conspicuously elevated, as
in Orbiculoidea Newbernji, and it may be quite proper to regard these two species
as forms in which the development of this feature has been arrested at an
earlier stage in one {D. pleurites) than in the other. With our present compre-
hension of the genera Schizocrania and Trematis, it is impossible to admit
this species to either, for no specimen has shown a trace of muscular imprints,
which are usually very strong in the upper valves of both these groups.

* See in Supplement dosm-iptiim of Scfihocrania? Heldei-bergia, sp. nov.

BRACHIOPODA. 133

IC

Neither can it be assigned to Okbiculoidea without opening that "enus to t
reception of heterogenous forms. For convenience, therefore, it is desirabk^ to
indicate the close but subordinate relations ol' this species* to Orbiculoidka,
by the use of the new term ^hlertella.

The muscular impressions in Orbiculoidka are extremely faint and rarely
discernible at all. We have seen no specimens showing them as clearly as the
pedicle-valve of D. nitida, figured by Mr. Davidson and referred to above, where
they are resolvable into anterior and posterior adductors, situated close together
near the extremities of the pedicle-area, the posterior pair being at the distal
extremities of long progressive scars radiating from near the apex. This
arrangement of the scars indicates a general agreement with the muscular
anatomy of Discinisca lamellosa.

Orbiculoidea Randalli, Hall, a remarkably large species, known only from a
single rather imperfect interior of the pedicle-valve, from the Hamilton group
of New York, shows a slight median septum passing from the apex forward,
comparable to that in Discinisca lamellosa; from this radiate a series of furrows,
probably of vascular nature, which lie only within the inner lamellae of the shell,
apparently not interrupting the external ornamentation. It will be interesting
to learn whether this shell is congeneric with Orbiculoidea Morrisi, Davidson.

Occasionally, in the brachial valves of American species, are seen two
extremely faint ridges beginning near the apex and approaching each other at
their anterior termination, nearly meeting the inconspicuous median septum.
(See Plate IV f, fig. 22 ; also, Barrande's figure of Discina reversa, Keyserling,
Systeme Silurien, vol. v, pi. 95, fig I, 2 a.) In a large form from the Hamil-
ton group of New York, usually confounded with 0. grandis, Vanuxem, these
characters reach an extraordinary development aud become most prominent
features of the interior, beginning just in front of the apex, and, as they con-

* The mode of preseivalion of this species freijuently leads to deception in regard to its pedicle-charac-
ters. When the two valves are preserved togetht^r, the breaking away of the upjiei' ]iorlion of the larger
valve often leaves its marginal portion surrounding the lower valve and closing the pedide-aperture. In
many such cases it is extremely clifficult to distinguish the parts belonging to the respective valves on ac-
count of the thinness of the shell, and we have taken pains to accumulate a very lai-ge representation of the
species in oi-der to fortify our conclusions. For much of the material at our disposal we are indebted to the
favor of Professor C. L. Herrick, of Cincinnati.

184 PALEONTOLOGY OF NEW YORK.

verge, making a very abrupt slope on their outer margins, but a gentle slope
inward. The median septum is very f;iint until it meets the lateral ridges,
when it widens over the anterior portion of the shell. Between each ridge and
the median septum the surface is marked by radiating muscular lines which
indicate the position of the anterior adductors, and at the posterior extremity
of each ridge lies a circular impression, undoubtedly of muscular origin, but
whose function is not disclosed by comparison with allied forms. Our present
knowledge is insufficient to determine the degree of development of these lateral
muscular ridges throughout the " Discinas," but in the typical forms upon
which we have based the discussion of the foraminal characters they do not
appear at all, and we are disposed to regard them at least as of subsidiary generic
importance, and propose to place this Hamilton species under the sub-generic
term

LiNDSTRCEMELLA, sub-gen. nov. (See Plate IV e, figs. 25-28.)

Diagnosis. Sliells with outline, contour and pedicle-characters as in Orbi-
CULOIDEA. Brachial valve with a faint median septum and two strong approx-
imating ridges or muscular fulcra, beginning just behind a transverse line
passing through the apex and rapidly converging to meet the median septum.
Anterior adductor scars lying between these ridges and the median septum ;
a circular muscular scar at the posterior extremity of each ridge.

In the pedicle-valve, the foramen has essentially the structure of Orbiculoi-
DEA, but its distal margins, though lying in close juxtaposition appear not to
have been united.

Type, Lindstramella aspidium, sp. nov.*

In the pedicle-valves of " Discinas " are often seen traces of what, at first
sight, appear to be similar, though faint ridges, situated, however, further back-
ward, meeting at the apex and diverging along the pedicle-groove. We are
satisfied that this feature is produced by the flattening of the shell about the
more or less thickened internal pedicle-area and is purely accidental. In several
of M. Barrande's figures this feature is made to appear in various degrees of

* For description see Supplement.

BRACHIOPODA. 136

development cas a conspicuous character of the interior ; vide D. reversa ? PI. 96,
fig. I, 3 A, 4 A, 5 A, 6 A ; /;. tarda, PI. 96, fig. V, 4 a ; 1). rugata ?, PI. 98, fig. I,
6 c ; D. intermedia, PI. 99, fig. VI, 1 a, 2 a, 3 a, 4 a (Systvmo Sihn-ien, vol. v,
1879).

The fos.sils which have been referred to Orbiculoidea, Davidson, not
D'Orbigny, the best known of which are O. Forbesi, Davidson, and O. conica,
Dwight, differ from all the foregoing in having the perforated valve very con-
vex and the imperforate one depressed-conical (0. Forbesi), or Hat (O. conica).

This convexity of the pedicle-valve attains an amazing development in Pro-
fessor Dwight's remarkable species, the umbo being prolonged into a high cone,
with the apex inclined toward the anterior margin of tlie shell. The same
inclination is observable in specimens of O. tenuilamcllata , from the Niagara
group at Hamilton, Ontario, but only to a slight degree.

The pedicle-groove has essentially the character seen in Orbiculoidpu,
D'Orbigny, but is usually much more distinctly retaiiied on account of the
greater thickness of the shell, which is in striking contrast to its tenuity in the
last named group. A question may fairly arise as to the advisability of con-
sidering the diflerences mentioned in these two groups as of generic importance,
but it was upon a strictly congeneric species that Kutorga established the genus
ScHizoTRETA, a name which has uniformly been regarded as a synonym for
DisciNA ^ Orbiculoidea, Davidson, since Professor Morris' observation.s on tlie
subject in the Annals and Magazine of Natural History in 1849.*

To apprehend the proper status oi' this group, Kutorga's diagnosis is ap-
pended :

ScmzoTRETA, Kutorga. Ueber die Siphonotretaete ; Verhandl. der russ.-kais.
mineral. Gesellsch. zu St. Petersburg, pp. 272, 273. 1848.

" The chief character of this genus lies in the peculiar external slit-shaped
pedicle-aperture, the position of which is precisely the reverse of that in the
preceding genera | SiPiiOiNOXRETA, etc.]. The apex of the beak is greatly ele-
vated, but far from being in the center of the valve, and from it passes over
the strongly convex cardinal slope of the cone, toward the posterior margin, a

* Second Series, vol. iv, p. 31").

136 PALEONTOLOGY OF NEW YORK.

narrow elliptical slit, which extends scarcely for one-half the face of the cone,
thence merging into the inner sipho. The surface of the shell is covered with
simple, elevated, concentric lines of growth which are interrupted by the slit.
The ventral [= brachialj valve is very depressed-convex or even flat ; its beak
is sharply defined, depressed, directed toward the cardinal margin, and in no
sense marginal, for between it and the margin are several unbroken growth-
lines."

Further, under the discussion of the type-species, S. elliptica, Kutorga, the
author observes (p. 274):

" The study of the slit under the microscope, with an aplanative ocular and
enlargement of 45 diameters, convinces me that there is no fissure in the bot-
tom of the slit opening into the interior of the shell. It is very clearly seen
that the bottom is covered with the same epidermal layer crossed by fine
growth-lines; and, further, that the posterior end of the outer slit merges into
the cylindrical sipho."

It is important to have these latter observations in mind, for while they agree
minutely with the character of the aperture in Orbiculoidea, Davidson, the feature
is not so well understood from a study of Kutorga's figures. It thus appears
that there is no essential difference in Schizotreta, Kutorga, and Orbiculoidea,
Davidson, and the former term may very well stand to include those forms
essentially in agreement with Orbiculoidea, D'Orbigny, but having thicker
shells and the relative convexity of the valves reversed, bearing, in fine, the
same relation to D'Orbigny's genus as Strophonella to Strophodonta, among
the articulate brachiopods.

Professor Dwight has shown that the muscular impressions of the brachial
or imperforate valve in Schizotreta conico, consist of two strong excavated ante-
rior adductors approaching toward the center of the shell, and separated by a
prominent septum which is continued from a somewhat thickened posterior
muscular area. Better preserved interiors of this species will, no doubt, show
other scars and determine more closely its relations in these respects to Orbicu-
loidea nitida and Discinisca lamellosa.

Another peculiar phase of reversion in certain features characterizing the
typical Orbiculoidea, is seen in the species Disc.ina grandis, Vanuxem, a not

BRACHIOPODA. 137

uncommon form in tlie sandy shales of tlio Hamilton group. The upper
valve is elevated and obtusely conical, with its apex slightly posterior, while
the lower or perforated valve when uncompressed
is extremely concave, much more so on the ante-
rior than on the posterior slope, the entire surface
of the valve rising for a considerable distance into
the cavity of the other valve. Thus the general
contour of the pedicle-valve is precisely the re-
verse of that usual in OrBICULOIDEA, while the •■'■«• •"■ l>i«g>ammatic ngure of nwmerelta

grandU, sliowiug the concavity of tho

structure of the pedicle-aperture appears to be i>c.iicic-vaive.
essentially alike in both. This reversion is a sufficient basis for the separation
of this species and all others w'hicli may be found to agree with it in this
respect, from Orbiculoidea, and ^ve propose therefor the sub-generic terra,
RcEMERELLA, sub-gcn. nov.

Type, Ramerella grandis, Vanuxem. (See Plate IV i;, figs. 29-31.)

Orbiculoidea is not positively known as a member of faunas older than the
Silurian. The Discina Acadica of Hartt (Dawson's Acadian Geology, Second
Edition, p. 644. 1868), from the St. John formation, is not now regarded as a
brachiopod. Mr. Walcott refers it to the Gasteropod I genus, Palacm^a ?, and
Mr. Matthew to Stenotheca, s.g., Parmorphorella. Discina ? inutilis. Hall, from
the primordial sandstones at Mazomanie, Wisconsin, is verj- imperfectly known.
The American palaeozoic formations are known to contain about forty described
species of Orbiculoidea. The genus appears to have developed rapidly in
species and have attained a culmination in tho Middle Devonian faunas, from
which a considerable amount of undescribed material is to be found in collec-
tions. In the Menevian of Wales, Discina pileolus, Hicks, appears to be a genuine
Orbicdloidea, and if so, may be considered as the earliest known representative
of the genus. The D. Caerfaiensis, Hicks, from the Middle Caerfai group of St.
Davids, is known only from its upper valve.

138 PALEONTOLOGY OF NEW YORK.

Genus TREMATIS, Sharpe. 1847.

I'l.ATK IV G, FIGS. 1-20.

1825. Oyhicida, Sowekby. Zdcilogical Journal, vol. ii.

1842. Orhlcula, Emmons. Geolojcii-al Survey N. Y., Rept. Second District, ji. 395.

1847. Oi-bicula, Hall. PaJfeontology N. Y., vol. i, p. 100, pi. xxx, fig-s. lla-d.

1847. Tmnath; Sharpe. Quarterly Joui-nal Geolog-ical Society, vol. iv, p. 66 (June).

1847. Vrhicella, D'Orbig.vt. Coinptes rendus, vol. xxv, p. 269 (August).

1853. TrematiSy Davidson. Inti-oduclion to Bi-itish Fossil Brachiopoda. p. 130.

1855. Treniatlt, Emmons. Aniei'ican Geology, pt. 2, p. 201. tig. 63.

1859. Tnmatis, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 72.

1862. Treviatis, Billings. Palaeozoic Fossils, vol. i, pp. 52, 53.

1866. Tninatls, Hall. Descr. New Species Crinoidea and other Fossils, etc.

1866. Disr'ma {Ti-emath), Davidson. British Silurian Brachiopoda, pp. 69-71.

1871. Di.i<:ina {Trematis}, Davidson. British Silui'ian Brachiopoda, p. 344.

1871. Ti-ematis, Dall. Bull. Mus. Coinp. Zoology, vol. iii. No. 1, p. 37.

1872. Trniiatii, Hall. Twenty-fourth Rept. N. Y. State Mus. Nat. Hist., p. 221, pi. 7, tigs. 22-25.
(?) 1874. Tre^iuitis, Miller. Cincinnati Qu.art. Journ. Science, vol. i, p. 347.

1875. Trematls, Hall. Twenty-third Rept. N. Y. State Cab. Nat. Hist., p. 243, pi. xiii, tigs. 17-19.

1875. Trniialix, Hall and Whitfield. Geol. Surv. Ohio ; Palaeont., vol. ii, p. 70, pi. i, tigs. 4-9.

1875. TreiiKitis, Nich<)L.son. Palieontology of the Province of Ontario, p. 18.

1878. Tniiiatis, Miller and Dyer. Contributions to Palaeontology, No. 2, p. 8.

1889. Treiiiatlf, I'lrich. American Geologist, vol. iv, pp. 22, 23.

Diagnosis. Shell subcircular or transversely oval in outline. Pedicle-valve
unevenly convex, more or less depressed over the posterior region ; apex at, or
behind the center ; directly beneath it begins the pedicle-lissure, which tran-
sects the shell, vertically widening to the posterior margin with straight or
outwardly curving edges. Brachial valve evenly convex, with its apex mar-
ginal and slightly projecting. On the interior, the pedicle-valve shows a faint
median furrow extending from the angle of the fissure to the apex of the shell ;
this groove widens at its apical termination and may represent a point of mus-
cular attachment. The sides of the fissure are often thickened by callosities
similar to those sometimes seen in species of Orbiculoidea. From the apex
of the valve extend radiating and branching vascular sinuses.

In the brachial valve the posterior margin is much thickened and broadly
grooved to allow the extrusion of the pedicle. This thickening does not take the
form of a cardinal area or shelf, but is rather a callosity closely appressed against
the interior surface of the shell, the central portion being projected beyond the
margin of the pedicle-valve. Directly below and in front of this area are two

BRACHIOPODA. 139

transversely elongate scars, adjusters or posterior adductors, which are usually
partly concealed by the progressive overgrowth of the cardinal thickening. A
faint median septum begins between these scars and passes forward, becoming
more prominent over the tongue-shaped median elevation which separates the
large central scars. These impressions are oblique and are not simple, each ap-
pearing to be composed of two, if not three distinct scars, making a posterior, a
median and an anterior pair. What appears to be the posterior pair is small,
and sometimes quite sharply defined, the central pair very much larger, and
the anterior pair narrow, situated at either side of the angle of the median
callosity and separated by its apex. The specialization of the first of these
scars is not satisfactorily established ; the entire impression is deeply excavated.
In some well preserved specimens, there is also evidence of external, mar-
ginal scars lying just in front of the outer ends of the posterior adductors.

Surface of both valves more or less completely covered by a beautiful orna-
mentation consisting of punctures or small pittings of var3dng depth, arranged
either in quincunx (T. terminalis) or in radiating rows; in the latter case they
may be distant from one another without intervening ridges (T. umbonata), or
lie in radiating furrows, when they are either circular (T. inillepundata) or sub-
rectangular (T. Ottawciisis).

Shell-substance composed of an outer calcareous layer with a series of inner
corneous lamellae. The outer layer varies in thickness in different species and
is coarsely punctated by tlie pittings constituting the surface ornamentation.
The corneous layers are impunctate.

Type, Trematis terminalis, Emmons.

Observations. The interior of the brachial valve in this genus presents at
first consideration a striking similarity to that of the pedicle-valve in Obolus.
In both the arrangement of tlie muscular scars is essentially into three pairs :
(1) the posterior adductors (cardinals in Obolus), (2) the anterior adductors,
(3) the externals. The second of these pairs is strongly excavated in both genera
and bordered by a median thickening. Herein lies the difference in both these
genera from Dinobolus, with which there is a superficial agreement ; these

140 PALAEONTOLOGY OF NEW YORK.

muscular impressions in that genus lying upon the median thickening but in
front of it in the others. The presence of a median septum in both Obolus
and Trematis adds to their similarity. The large median scars in Trematis,
however, are composite, and thus indicate an important difference in the char-
acter of the muscular anatomy of the two genera. In position, if not in func-
tion, the anterior and median members of the great central scars in Trematis
correspond with the anterior laterals and centrals in the brachial valve of

LiNGULA.

In Schizotreta (=Orbiculoidea, Davidson; see pp. 120, et seq.), we find a gene-
ral correspondence in the character of these impressions, although our knowledge
of the muscular scars of the brachial valve in that group is limited to a single
species, S. conica, Dwiglit, and in this case only to the two large central scars,
parted by a thickened median area and septum. In the absence of satisfactory
evidence concerning these important characters in the brachial valve of Orbicu-
loidea, D'Orbigny, we may assume that their arrangement is indicated by what
is known in the ca.se of Schizotreta, a group very closely allied in other
respects.

In the pedicle-valve of Trematis there is an apparent correspondence in the
character of the pedicle-opening with the forms which have been referred
above to Orbiculoidea, D'Orbigny. In the discussion of these fossils it has
been shown that the aperture is not an oval perforation as in Discinisca, or a
fissure extending to the margin as in Trematis, but a tubular oblique passage,
most closely allied to that in Siphonotreta. The homology in this respect
then becomes remote, though distinctly traceable through the aberrant Discina
{(EhUrtella) pleurites, and perhaps is even more direct in the case of Lindstrcem-
ella. Schizobolus, Discinolepis, ScHizocfiANiA and perhaps Kutorgina conform
with Trematis in having the aperture a radial incision, and as the nature of the
pedicle-opening must be considered as of radical importance in determining the
taxonomy of the inarticulate genera, the groups named will fall into close
contiguity. It has been shown how closely Schizobolus is allied to Obolella
in" the character of its muscular anatomy, and that Kutorgina probably repre-
sents an incipient stage in the development of the Siphonotretoid pedicle-tube.

BRACHIOPODA. 141

Of DisciNOLEPis little is known except its external conformation, while Schizo-
cRvxiA expresses the extreme resnlt of this tendency to marginal development
in the aj^erture, an effect wliich comes by the way of Trumatis.

Two months after the pnblication of the term Tri:m.\tis by Sharpe, D'Orbigny
proposed the name Orbiteij.a for similar fossils having a supposed punctated
shell-structure and a convex pedicle-valve ; but no typical example was cited
by him until, in his "Prodrome de paleontologie stratigraphiqne,"* nine sjjecies
were referred to his genus, tlie first of which is the Orbicula Buchi of Verneuil.t
It appears evident that D'Orbigny's comprehension of his genus was equivalent
to that of Sharpe for Trematis, as in his list both Orbicula terminalis, Emmons,
and 0. ? punctata, Sowerby, are cited. It is necessar\-, however, to take Orbicula
Buchi as the type of the Orbkella, and it does not appear from Verneuil's
description that this species is congeneric with Trematis terminalis. No mention
is made of a punctated external layer, though this may have been accidentally
absent in Yerneuil's specimens ; the fissure is described as lanceolate and not
extending to the border.^

It has been observed elsewhere that this Orbicula Buchi is the species taken
by Pander in 1861 as the type of his genus Keyserlingia (see page 117), and
that by a strict construction of tlie rules of precedence, Orhicella must stand
in place of Pander's term. Thus while D'Orbigny's Orbicella, under the
author's conception of the group, is synonymous with TREMATrs, and must be
abandoned in this connection, it is rehabilitated as a genus by Pander's invest-
igations.

The genus Trematis appears to be largely confined to American Silurian
faunas. The published evidence in regard to the character of the pedicle-
apertux-e in all the British species referred to this genus in the lists accompan}--
ing Davidson's General Summary (T. Siluriana, Davidson, T. punctata, Sowerby,

* 1849, p. 2U.

t Geol. Riissie d'Europe et des raont. de I'Oural, p. 22S, pi. xix, fig-. 1. 1845.

t It may be noticed that Mr. D.wid.son'.s elegant figure of Tremafii punctata, as well as the desci-iption
of the same species (British Silurian Brachiopoda. p. 69, jil. vi, fig. 9 a), gives the pedicle-fissure the same
character ; probably an eri-oi- aiising from imiierft'ct preser\ation of the specimens, but in case the charac-
ter of the pedicle-aperture has been correctly represented, the species can not be congeneric with Trematis
terminalis.

142 PALAEONTOLOGY OF NEW YORK.

and T. corona, Salter ; T. cancellata, Sowerby, does not appear in the catalogue),
is meager and extremely unsatisfactory, though we may assume that the un-
certainty in regard to these points will soon be cleared away. Barrande's
Trematis Bohemica* is unquestionably a Dinobolus. At present we are able to
recognize eleven species as undoubtedly congeneric, in addition to which are three
of questionable affinity which are little known. All these are confined to the
Trenton and Hudson faunas of the Silurian, and the earliest to appear is
Billings' T. Hurmiensis, from the Black River limestone.

The list of species is as follows :

Trematis terminalis, Emmons. Trematis quincuncialis, Miller and Dyer.

Trematis Montr ealensis, Billings. Trematis umbonata, Ulrich.

Trematis Ottawensis, Billings. Trematis fragiUs, Ulrich.

Trematis Huronensis, Billings. Trematis ohlata, Ulrich.

Trematis millepmdata. Hall. ? Trematis pustulosa, Hall.

Trematis pundostriata, Hall. ?? Trematis rudis, Hall,=ScHizocRANiA (?).

Trematis crassipunda, Ulrich. ?? Trematis Di/eri, Miller.

Genus S C H 1 Z 0 C R A N I A, Hall and Whitfield. 1875.

PLATE IV G, FIGS. 21-35.

1847. OrUcida, Hall. Pal.-eoijtologry N. Y., vol. i, p. 99, pi. Ixxx, tigs. 9 a-d.

1863. Trevuitli, Billing-s. Rept. Progress Canadian Geological Survey, p. 159, tig. 126.

1873. TrimatU, Hall. Tweiity-lliird Kept. N. Y. State Cab. Nat. Hist.. Expl. pi. xiii, tigs. 21, 22.

1875. &lnzocmnw. Hall and Whitfield. Geol. Ohio ; Paljeont., vol. ii, p. 73, pi. i, figs. 21, 22.

(?) 1878. Trematis (SMzdCvania), Barrett. Ann. New York Academy of Sciences.

1884. {Dlicinocaris >). Davidson. General Suninnny of the British Brachiopoda, p. 352.

Diagnosis. Shells sub-circular in outline, inequivalve, unarticulated. Pedi-
cle-valve flat or concave ; apex subcentral. A deep triangular notch extends
from just behind the beak to the margin, where its arc is equal to about one-
sixth of the periphery. The apex of this broad pedicle-notch is occupied by a
triangular transverse plate varying in size with the age of the shell, but ex-
tending for one-fourth to one-third the length of the opening. Surface marked
by concentric groAvth-lines. On the interior no muscular impressions are vis-

* Syst. Sil. Boheme, vol. v, pi. 94, fig. vi. 1879.

BRACHIOPODA. 143

ible. Brachial valve more or less convex, with the beak marginal. External
surface radiately striated. The interior bears a pair of strong posterior
adductor scars, lying close together in the umbonal region ; their outline is
elongate-ovate, indicating a progressive increase in size, and they irequently
appear to be divisible into anterior and posterior elements. In front of them,
at about the center of the valve, are the small and fsiint anterior adductor im-
pressions. A low median ridge extends from the apex to beyond the center of
the valve. External surface marked by elevated stria? radiating from the
beak.

Substance of the shell composed of perlaceous calcareous laminae which
constitute the most of the shell. The inner layers appear to be corneous. All
are impunctate (?).

Type, Schizocrania filosa, Hall.

Observations. We have knowledge of but two clearly defined species of this
remarkable genus, the type, a not uncommon form in the Hudson group
in Ohio and Kentucky, usually occurring attached to foreign bodies, not infre-
quently to valves of Sfrophomena alternata; a shell often of considerable size in
these localities but represented in the Utica slate of New York by a rather
diminutive form ; and a second .species, here described under the name S. Schu-
cherti, from the Utica horizon of the Cincinnati group at Covington, Kentucky.
It was observed in the original discussion of this genus that these fossils were
probably parasitic or adherent by the surfaces of their lower valves, as in
the case of most palfBOzoic Cranias. It seems necessary to modify this
opinion as our present material ailbrds evidence that tlie lower surface of the
pedicle-valve retains its concentric markings with no trace of conformation to
the body to which the animal may be attached. The pedicle itself was, if we
may judge from the size of the aperture, of very great strength and the pedi-
cle-valve, being of somewhat less diameter than the brachial, was overlapped
by it, and it is very apparent that this overlapping edge of the upper valve has
formed an important accessory means of attachment. (See Plate IV g, figs. 25,
29, 33-35.)

144 PALEONTOLOGY OF NEW YORK.

It is also frequently observed that attached shells from which the upper
portion of the brachial valve has been broken, show the lower valve to have
slipped out of its normal position without being able to escape from the inter-
nal cavity of the shell. Furthermore, the Schizocrania filosa of the Utica slate
of New York is usually found free, and of thirteen examples before us of S.
Schucherti, none are attached; which facts together induce us to believe that a
parasitic habit requiring the modification of either valve to any such degree as
in Crania, can not properly be considered a character of the genus.

The transverse plate in the apex of the notch in the pedicle-valve is directly
comparable to the similar structure in CEhlertella pleurites, and is undoubtedly
homologous with the external pedicle-groove seen in Orbiculoidea and ScHizo-
TRETA. In Schizocrania it has formed a surface over which the pedicle passed,
increasing in size with age and becoming a conspicuous feature in old shells.
The plate is not elevated or depressed above the plane of the valve as it is in
(E. pleurites, but it shows the median ridge projecting at the margin, a feature
which is strongly marked in the latter species. (See discussion of CEhlertella
on pages 120, et seq.)

In addition to the two species of the genus mentioned as occurring in the
fiuna of the Hudson group, are two other species in the Lower Helder-
berg fauna, less completely known but giving indications of structure similar
to that of S. filosa. These are the form described in the Supplement to this
volume as S. (?) Helderbergia, sp. nov., and that mentioned by Barrett in the
citation above given as Trematis (Schizocrania) superincreta. The species de-
scribed as Trematis rudis. Hall, from the Trenton limestone at Clifton, Tennessee,
is also imperfectly known, but may prove a Schizocrania.

BRACHIOPODA. 145

Genus CRANIA, Retzius. 1781.

PLATE IV H, FIGS 1-35.

1732. Numuhis, Stob<eds. Dis.sertatio epistolica.

1760. Anomia {partiin), Linne. System.i Natnrse, Eil. x, p. 700.

1776. Ostracites, Beuth, Juliae et Moiitium sul>tei'raiiea, etc.

1776. Patella, Mollbr. Zoologiae Danicae Pi-oiliomus.

177S. Numulus, Waller. Systema Miiieialogioum, vol. ii, p. .")00.

17S1. Crania, Retzids. Schriften dei- Bei-lin. Gesellsch. natuiforsch. Freuiuien, vol. ii, j). 72.

1791. Criopus, Poll Testacea utiinsque Sic.iliae, etc., vol. i, p. 34.

1795. Criopoderma, Poll Testacea utriusque Sicilia;, etc., vol. ii.

1798. Orhicula, Cuvibr. Tableau eli'mentaire de I'histoire nat. des aniinaux, p. 435.

1799. Orhiciila, Lamarck. Prodrome, p. 83.

1806. Oihiculanits, Dcmeril. Zoolog-ie analytique, p. 168.

1820. CranioUtts, S^hlotheim. Die Petiefakteiiktinde auf ilir. jetz. Stamlimnkt, p. 247.

1849. Crania, CriopiLS, KixG. Mong-r. Permian Fossils of England.

1854. Ckoniopora, Schaurotu. Zeitschr. der deutsch. geol. Gesellsch., vol. \ i, p. 546.
Crania, of recent writers generally.

(?) 1847. Orbiada, Hall. Palseontology N. Y., vol. i, p. 23.

(?) 1856. Orbicida, Emmoks. American Geology, p. 112.

1859. Crania, Shdmard. Trans. St. Louis Academy of Sciences, vol. i, p. 395.

1860. Crania, Hall. Canadian Naturalist and Geologist, vol. v, p. 144.

1860. Crania, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., pp. 77-79.

1862. Crania, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pp. 182, 183.

1863. Crania, Hall. Sixteenth Rept N. Y. State Cab. Nat. Hist., p. 31.
1863. Crania, Hall. Trans. AHiany Institute, vol. iv, pp. 208, 209.

1865. Crania, White. Proc. Boston Soc. Nat. History, pp. 29, 30.

1866. Crania, Wikchell. Rept. Lower Penin. Michigan, p. 92.

1866. Crania, Hall. Pamphlet : Advance sheets Twenty-fourth Rept. N. Y. State Mus. Nat. Hist.

1867. Crania, White ami St. Johs. Trans. Chicago Acad. Sci., vol. i, p. 118.

1871. Crania, Dall. Bull. Mus. Comp. Zoology, vol. iii. No. 1, p. 27.

1872. Crania, Hall and Whitfield. Twenty-fourth Rept. N. Y. State Mus. Nat. Hist., p. 187.

1873. Crania, Hall and Whitfield. Twenty-third Rept. N. Y. State Cab. Nat. Hist., p. 236.

1874. Crania, Derby. Bull. Cornell University, vol. i. No. 2, p. 60.

1874. Crania, Billings. Paleozoic Fossils, vol. ii, p. 15, fig. 5.

1875. Crania, Miller. Cincinnati Quarteily Journal of Science, vol. ii, p. 13.

1875. Crania, Hall and Whitfield. Geology of Ohio ; PaL-eontology, vol. ii, i)p. 74, 75.

1875. Crajiia, Hall and Whitfield. Twenty-seventh Rept. N. Y. State Mus. N.at. Hist. : Expl.pl.

ix, figs. 36, 37.

1875. Crania, Nicholson. Rept. Palaeontology Province of Ontario, p. 82.

1878. Crania, Ulk.ch. Journal Cincinnati Soc. Nat. Hist., vol. i, pp. 98, 99.

1879. Crania, Hall. Tiansactions Albany Institute, vol. x ; Abstract, p. 13.
1879. Crania, Hall. Pateontology N. Y., vol. v, pt. ii, pi. Ixxxviu, fig. 2.
1879. Crania, James. The Pala;ontologist.

1879. Crania, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 14S, pi. xxi, figs. 8-10.

1880. Crania, N. H. Wlvchell. Eighth Ann. Rept. Geological Survey of Minnesota, p. 63.

1881. Crania, Hall. Eleventh Ann. Rept. State Geologist Indiana, pp. 282, 283, pi. xxvii. fig. 1.

1882. Crania, Whitfield. Description of New Species of Fossils from Ohio, p. 229.

1883. Crania, Gdelby. New Carboniferous Fossils.

146 PALEONTOLOGY OF NEW YORK.

1884. Crania, White. Thii-toeiith Kept. State Geologist Indiana, p. 121.

1884. Crania, Spexoer. Bnll. No. 1, Mus. Univ. State of Missouri, p. 57.

1886. Crania. Rtxouekkrr. Bull. Buffalo Soc Nat. History, vol. v, pp. Iti, 17.

1889. Crania'?, Walcott. Proceeding-s United States National Museum, 1888, p. 441 ; Advance sheets.

1889. Crania, Beecher and Ci..\rke. Memoirs N. Y. State Museum, vol. i, No. 1, p. 13.

1889. Crania, Nettelkoth. Kentucky Fossil Shells, p. 2.

Diagnosis. Shell inequivalve, inarticulated, without perforation for a pedicle ;
subcircular in outline, generally somewhat transverse across the posterior mar-
gin ; attached by the apex or the entire surface of the lower valve. Ventral
or lower valve depressed-conical or conforming to the surface to which it is
attached. Dorsal or upper valve more or less conical with a subcentral, poste-
riorly directed apex. External surface of the valves usually smooth, sometimes
spinose or with concentric or radiating strise. In the interior of both valves
are two pairs of large adductor scars, the posterior of which are close upon the
margin and widely separated, the anterior near the center of the shell and
close together, more approximate in the lower than in the upper valve. These
posterior scars are often strongly elevated on a central callosity which sur-
rounds their anterior margins. The margin of the lower valve is usually broad
and thickened. Impressions of the pallial genital canals coarsely digitate.

Shell-substance calcareous ; strongly punctated by vertical canals which be-
come subdivided toward the epidermal surface.

Type, Crania craniolaris, Linne.

Observations. Crania is remarkable for presenting an association of shell-
characters which have undergone no essential change from the earliest known
appearance of the genus in Lower Silurian faunas to the present. Indeed
neither paleozoic nor recent species indicate material variation from the type
of internal structure found in C. craniolaris, while certain Mesozoic forms (C.
Parisiensis, Defrance, from the Jurassic, C. tripartita, Miinster, of the Cretaceous,
etc.), give evidence of so great departure from the type in the development of
internal diverging septa, in one or both valves, that separate subdivisions have
been established for their reception; viz., Ancistrocrania and Craniscus, Dall,
respectively.

The degree of attachment of the lower valve has been made a basis of sub-

BRACHIOPODA.

147

division by some authors. King* proposed to limit the term Crania to such
species as are attached by the uniboiuil portion of the lower valve, e.g., C. Igna-
bergensis, and to apply the name Criopus, which had been proposed by Poli in
1791 {be. cit.) for the animal of Crania and some other brachiopods, to species
attached by the entire surface of this valve. It is a well known fact that many
species of Crania were quite unattached during their mature life, and other
species are known to have been either attached or free. It therefore appears
injudicious to ascribe a high value to so variable a character as the degree of
attachment of the lower valve.

Among Cranias generally there is a more or less distinctly developed tend-
ency to the formation of a transverse posterior or cardinal margin, a feature
reaching an extreme in Waagen's genus, Cardinocrania.

It is not usual to find among palaeozoic species any indication of more than
two pairs of muscular impressions, the posterior being divaricators and the
anterior, occlusors or adductors. The other small muscular bands rarely leave
discernible scars, but their position may be learned from the accompanying
figures of Crania anomala, Midler, reproduced from Dr. Davidson's Monograph
of Recent Brachiopoda,! and made from sketches by Mr. Albany Hancock.

Crania anomala. After Hancock.
FIG 66. Dorsal surface of the a..ira.-,l. Fig. 67. Ventral surface,

mm mesenteric muscle; <ii, divaricators; da, dorsal aUjustors; ra, ventral adjustors; oc, occlusors; tm brachia
muscles; bp, brachial process; oc, alimeutary canal (According to Joubin, this organ should have a median, not
lateral termination).

In addition to the large muscular bands are three pairs of smaller ones ; da,
va, the dorsal and ventral adjustors respectively, and bm the brachial muscles,

* Monograph of the Pei-mian Fo.^sils of England, p. 84. 1849.
t Trans. Liiinean Soc. London, vol. iv, pt. 3, p. 187. 1888.

148 PALEONTOLOGY OF NEW YORK.

which, according to Hancock, have both their extremities attached to the same
valve (dorsal) ; mm is the median or mesenteric muscle, probably acting as a
support to the viscera. Mr. Davidson has given figures of a dorsal valve of
Crania (Pseudocrania) divaricata, in which these minor impressions are shown,*
and they may be seen more or less distinctly on some of the accompanying
figures on Plates IV h and IV i.

The external surface of the upper valve in palaeozoic Cranias is either smooth,
that is with only the concentric lamellose growth-lines ; covered with radiating,
elevated, frequently dichotomizing costse ; or minutely spiniferous. In the first
mentioned condition the surface is very generally modified by the contour of
the body to which the lower valve is attached, and in most of these smooth
species there appears to have been great indifference as to the zoological nature
of the host. For example, C. (Craniella) Hamiltonm is shown upon Plate IV i to
bear the surface-characters of Tropidoleptus carinaius, Spirifer audaculus, Microdon
(Cypricardella) bellistriatus, and it is often found on other species of mollusca,
and rarely upon trilobites and corals. Among the smooth forms occurring
in the Hudson fauna in Ohio and Kentucky, are several to which various
specific names have been applied in accordance with the modification of the
surface from attachment to different hosts ; C. scabiosa, Hall, often with a
considerable degree of convexity and a smooth exterior, usually adheres to
Strophomena alternata, or some species of Orthis, and to individuals having the
parallel markings corresponding to the strisB of those shells, Mr. Ulrich has
given the name C. parallela. Less frequently the same species attaches itself
to gastropod shells of the genera Pleurotomakia, Cyclonema, etc., or to small
crinoid stems, or to the surface of monticuliporoid corals, undergoing in each
case just such modifications as the circumstances have required. These varia-
tions pass under the names C. percarinata, Ulrich, C. socialis, Ulrich, and C. mul-
tipundata, Miller, a subdivision wholly based on accidental characters. Indeed,
among most of the smooth species in palaeozoic faunas, unless there is some
evident difference in interior character, a specific designation can hardly serve
a broader purpose than to indicate a different association. The plicate or

* British Silurian Brachiopoda, pi. viii, figs. 11, 11a, 12 a.

BRACHIOPODA.

149

spiiiiferous Cranias never evince more than a very slight tendency to surface
modification from attachment.

The shell-structure in this genus is essentially calcareous and composed of
two layers, the inner of which is the thicker, the outer being thin, dark colored,
epidermal. It is strongly punctated by vertical tubules, the openings of which

Fig. GS. Verlical suction of the shell of the upper valve
of Crania anomala (after King), showinjjthe arbores-
cence of a tubule on approacliing the outer surface.

Kic. 09. Uorizontal sectioiijust beluw ilui
upptu- hurface. AUer KrN<;.

on the internal surface may, under good preservation, be seen with the naked
eye. It has been shown bj- Carpenter,* KiNof and Joubin,| that these tubules
are widest at their inner extremities, and as they reach the epidermal layer in
the upper valve they ramify and become aborescent, making an irregular plexal
opening on the surface. From Joubin's observations this aborescent character
does not appear to exist in the attached valve.

In respect to muscular anatomy there is little reason to doubt the closer re-
lation of Crania to Discina and Discinisca than to any other of the inarticulates.
The four large impressions in each genus occupy correlative positions, and
though Mr. Davidson terms the posterior pair in Crania (Pseudocrania) divaricaia,
divaricators, and those in Discinisca, adductors, we can lind no authority for
ascribing different functions to the muscles they represent. But in the entire
absence, in any stage of the development of the shell, of pedicle or foramen,
and in the calcareous nature of the shell-substance, Crania stands far apart
from all other members of the class ; and Joubin has observed that it is the
only known brachiopod which has the anal opening exactly in the median line.

There is no evidence that Crania has been a member of faunas older than
the Silurian, and no indubitable proof of its appearance earlier than the Tren-

*0n the Intimate Striictin-e of the Shells of the Brachiopo Js : Davidson's Introduction to Bi-itish Fossil
Brachiopoda, chap. ii.

t On the Histology of the Test of the Chiss Palliobi'anchiata : Trans. Royal Irish Academy, vol. xxiv.

J Recherches sur I'Anatomie des Brachiopodes Inarticules : Archives de Zoologie Expt-rimentale, t. iv.
ISSti.

150 PALEONTOLOGY OF NEW YORK.

ton. The Crania ? Columbiana, Walcott, from the primordial beds of the Mt.
Stephen section, British Columbia, is thus referred from external characters
only ; the imperfectly known fossil described in vol. i of the Palaeontology of
New York (p. 2S), as Orbicula deformata, from the Chazy limestone, has an
exterior suggestive of Crania, but may be a discinoid. The earliest clearly
defined species are C. Trentonensis, Hall, and C. setigera, Hall, from the Trenton
fauna; throughout the Palaeozoic the genus fails to reach a very abundant
development in species, though in some faunas these species were very prolific
in individuals. The number of recognizable species now known from American
palaeozoic rocks will not exceed thirty.

A few words are necessary in regard to the type-species of Crania. Accord-
ing to Dall,* Retzius confounded under the name C. Brattensburgensis, the
Numulus Brattensburgensis of Stobceus, 173 i, the Anomia craniolaris of Linnb,
1760, and a recent species believed to be the Patella anomala of Mitller, 1776.
Davidson adopted the term C. Brattensburgensis, Stoboeus, not Retzius, as the
typical species, but as it has been conceded by most authors that this is iden-
tical with Linne's Anomia craniolaris, Dall would make the latter stand as the
designation of the type on the ground that Stob(eus was not a binomial author.
Under the discussion of the genera Discina, Orbiculoidea, etc., attention has
been called to the fact that the Orbicula of Cdvier, established on the Patella
anomala of MItller, is a synonym for Crania wherever used by authors in the
Cuvierian .sense. The Orbicula of Sowerby, 1822, and wherever the term has
been used by other authors with the same meaning, is synonymous with "Dis-
cina " [^= Orbiculoidea, D'Orbigny).

The term Choniopora was applied by ScHAUROXHf to a Permian fossil
considered by him as representing a new generic form of Bryozoan. It
was subsequently shown by GeinitzJ that the fossil to all external appearances
is a Crania with radiately striated and granulated surface, and was described

* Bulletin Museum Comparative Zoology, vol. iii, No. 1, p. 30.

t Zeitschr. der ileutsch. geolog. Gesellschaft, vol. vi, p. 546. 185).

lUyas, Heft. I, p. 109. ISGl.

BRACHIOPODA.

151

by him as C. Schaurothi. Dall suggests* that the species may represent a valid
subdivision of the genus Crania ; but while the interior remains unknown, and
the exterior is so similar to that of such species as C. setifera, C. setigera and C.
spinifera, it would seem injudicious to assign it a distinct generic position.

The generic term Pseudocrania, McCoy (Annals Nat. Hist., Second Series,
vol. viii, p. 387), was proposed in 1851. The following diagnosis was given in
British Palteozoic Fossils, p, 187. 1855:

" Shell slightly inequivalve, free; both valves regular, depressed, subconical,
unattached ; dorsal valve with or without a small cardinal area ; internally,
margin broad, flat, smooth or minutely striated concentrically ; anterior pair of
muscular impressions much larger and more strongly marked than the posterior
pair ; pallial impressions numerous, linear, not interrupted along the middle.

" This palaeozoic genus diflfex-s from the true Craniae in the following points:

(1) Crania is attached by the substance of the dorsal valve, and exhibits
thereon an irregular scar ; both valves are free and regular in Pseudocrania :

(2) in Crania the posterior or marginal pair of adductor muscles are always
larger and deeper than the medial or anterior pair ; the reverse is remarkably
the case in the present genus, which also has a smooth or minutely striated
margin, destitute of the strong granulation and punctures of most Cranige.
The Crania antiquissima, as given by Verneuil, may be taken as a type of the
genus, as also the following species " (^Pseudocrania divaricata, McCoy.)

The first of these typical species, the
Orbicula antiquissima, Eichwald,f = Crania
antiquissima, Verneuil,| as represented by
the latter author, shows a close similarity
to Pholidops, Hall, in the character of its
muscular scars. These are delineated as
two central impressions abutting against a

conspicuous posterior callosity, no evidence fig. 71. interior or lower valve.

appearing of any posterior marginal scar corresponding to the posterior ad-
ductors or divaricators of Crania. Mr. Davidson§ subsequently demonstrated

Pseudocrania divaricata.

After Davidson.

Fig. 70. Interior of upper v.ilve: a, a'Uluctors; J, ail-

justors; m, mesenteric; r, divaricators; n.brachials.

* Bulletin No. 8, U. S. National Museum, p. 19.

t Silurian System in Estbland, p. 169. 1840.

X G4ol. do la Russ. de I'Eurojie, etc., p. 289, pi. i. tijr. 12.

§ Silurian Brachiopoda, p. 79.

IS45.

152 PALEONTOLOGY OF NEW YORK.

the existence of these posterior scars in the Russian species and was inclined
to regard the specific difference in the Orbicula antiquissima and Pseudocrania
divaricata as not great. With Pholidopp, therefore, they can agree only in the
fact of being unattached shells, the two distinct pairs of muscular impressions
on the inside and, in P. divaricata, the posterior beak and radiating ornamenta-
tion on the exterior, separating them definitively from this genus. The features
upon which McCoy proposed to separate these species from Crania should not
be given too great importance ; the unattached habit of the shells throughout
their existence may prove of value as a basis for a section of the genus Crania,
but the fact that the central muscular impressions are often larger than the
anterior, Avill not hold good for these forms only, as it is often seen in the
American species of Crania. We are disposed to agree with Mr. Davidson in
regarding Pseudocrania as synonymous with Crania. Pseudocrania divaricata
is from the Bala limestone and Llandeilo flags ; P. antiquissima from the Vagina-
teii-l\alk, near St. Petersburg.

EicHWALD,* in 1860, proposed to designate the species, Orbicula antiquissima,
by the term Pal^oceania, as it differs from Pseudocrania divaricata in the cen-
tral position of the beak and the concentric markings of the shell. This
proposal however is illegitimate, as 0. antiquissima was the first type of Pseudo-
crania and therefore is not available as the basis of another genus.

Should these two species not prove congeneric either with each other or with
Crania, Eichwald's term will, under any circumstances, prove inadmissible.
When the Orbicula antiquissima becomes better known it may furnish a satisfac-
tory foundation for Pseudocrania as a genus.f

* Lethaea Rossica, vol. i. p. 909.

t The only American species which has been referred to Pseodoorania. is the Crania {Pseudocrania)
anomala of A. Winciiell, from the Hamilton group (Rept. Grand Traverse Region of Michiijan, p. 92. 186G).
By the favor of Professor Wincuell we have lieen allowed to examine specimens iigieeing with the original
description, and are compelled to prononnce the name a misnomer, as the species is a well defined strepto-
rhynchoid.

BRACHIOPODA.

153

Genus CRANIELLA, (Ehlert. 1888.

PI,ATE IV I, KIGS. I-IO.

18S8. Craniella. CEhi.krt. Bull, do la Soc. d'Kliules scientif. d'An^crt;, p. 87. 1SS7.
1889. Craniella, Kayser. Abliaiidl. iler KOnig-l. Prcu.ss. geol. Lundesanstalt, Nciie Folge, Heft i, p. B'l.
Crania, in part, of sfivoral aiithdi-s.

Diagnosis. " Shell somewhat irregular, outline subcircular or subquadraugu-
lar. Ventral valve thin, adhering by its entire sm-face ; dorsal valve conoidal,
more or less elevated ; apex subcentral, posterior ; interior of the dorsal valve
without a well defined border ; impressions of the
adductors large, very distinct, four in number, oi"
which the posterior two are quite distant, the two
subcentrals somewhat smaller, closely approximate
or even confluent; from near each of the posterior
impressions starts a vascular sinus, which is broad,
strongly sinuous near its point of dej^arture, nar-
rowing gradually in following the contour of the
valve, emitting from its marginal side dichotomiz-
ing secondary branches." ((Ehlert, loc. cit.)

Type, Craniella Meduanensis, ffihlert.

Observations. With the peculiar sigmoid vascular sinuses in the upper valve
as a distinctive character, we are disposed to regard this genus as well grounded.
This character is observed in an interesting species, Craniella Ulrichi, sp. nov.,
from the Trenton limestones at Minneapolis, Minnesota, and in the common
Crania Hamiltonicz of the Hamilton shales, and undoubtedly will be found to be
far more generally distributed as tlie interior features of the palasozoic Cranias
become better known. To the degree of attachment of the lower valve we
should ascribe less importance than does Dr. OLhlert. The Trenton species
mentioned is sometimes attached and evidently as often free, while C. HamiltmicR
appears to be, like C. Meduanensis, invariably adherent l)y the entire surface of
the lower valve.

7-*. CraniilUi Meduaiiensis.
Alter OinLEitr.
liitei-nal cast of upper \'alve.

154

PALAEONTOLOGY OF NEW YORK.

Genus CARDINOCRANIA, Waagen. 1885.

1885. Gard'mocmnia. Waaokn. Mem. Gecil. Siii-v. Inaia ; P.-i,I;eoiit. Indii^a, Ser. .xiii, vol. i, iv (fas. 5),

II. 745.

Type, Cardinocrania Indica, Waagen, loc. cit., pi. Ixxxiv, figs. 1, 2.

These very peculiar shells, of which only attached valves are known, have a
straight hinge-line which is set oflf from the remaining outline of the shell by
strong post-lateral indentations, giving the
valve somewhat the outline of the alate
strophomenoids, or still more suggestive
of the attached valve of Richthofenia (see
figures of R. Lawrenciana, Koninck, op. cit.,
plate Ixxxiii, figs. 1, a, b, c). This hinge,
however, is always edentulous, and is an
extreme specialization of the feature usually apparent as a transverse posterior
line in most of the Cranias. " In the interior of the valve the most conspicu-
ous part is a thin, triangular shelly plate, fixed by its broad base to the cardinal
region of the valve, and extending with its narrow and indented extremity to
not far from the front. It is supported in the middle by a low septum."
(Waagen, op. cil.) The arrangement of the muscular scars has not been
observed; notwithstanding, the known characters of the shells substantiate
the generic difference from Crania. The single known species is from the
Permo-Carboniferous beds of Salt-Range of India.

Cardinocrania Indica, Waagen.

After Waagen.

Figs. 73, 74. Inteiioi-s of attached valves.

BRACHIOPODA. 155

PHOLIDOPS, Hall. 1859.

PLATE IV I, FIGS. 17-:i7.

1820. PateJUtes, Schlothkim. Die Peti<>fakteiikuiuie auf ilir. jel/.ig. Stamlpiinkt.

1839. Patella {?), Sowebby. Murchisou's Silui-ian System, j). 62.'), pi. xii, tiff. 14 a.

1843. Orbicula, Hall. Geolog-y of New York ; Report Fourth District, p. 108, tig-. 1.

1847. OrUciila, Hall. Pateontology of New York, vol. i, p. 290, pL 79, tigs. 7 a, b.

1852. Orbiealaf, Hall. Paleontology of New York, vol. ii, p. 2.">0, pi. '>i. tigs. 4a, b.

1855. Orbiculoidea, McCoy. British Palaeozoic Fossils, p. 189.

1859. Craniops. Hall. Twelfth Rei>t. N. Y. State Cab. Nat. History, p. 84.

1859. Pholidops, Hall. Palaeontology of New York, vol. iii, pp. 489, 490.

1859. Crania, Discina, Saltkb. Mnroliison's Siluria, Second Edition.

1860. PhoUdops, Hall. Thirteenth Kept. N. Y. State Cab. Nat. History, p. 92.

1862. PhoUdops, Hall. Fifteenth Rejit. N. Y. State Cab. Nat. History, p. 195.

1863. PhoUdops, Hall. Sixteenth Rept. N. Y. State Cab. Nat. History, j). 31.
1863. PhoUdops, Hall. Trans. Albany I'istitute, vol. iv, p. 209.

1866. PhoUdo2}S. Hall. Desci-iptions New Sjiecies Fossils, etc. ; Advance sheets Twenty-fourth Rept.
N. Y. State Mus. Nat. History.

1866. Crania, Davidsox. British Silurian Brachiopoda, p. 80, pi. viii, tigs. 13-18.

1867. PhoUdops, Hall. Palaeontology of New York, vol. iv, pp. 31, 32, 413, 414, pi. iii, figs. 1-11.

1871. PhoUdops, Dall. Bull. Mus. Conip. Zoology, vol. iii. No. 1, p. 27.

1872. PhoUdops, Hall. Twenty-fourth Rept. N. Y. State Mus. Nat. History, p. 221, pi. vii, figs. 8-10.

1873. PhoUdops, Meek. Geol. Surv. Ohio ; Palaeontology, vol. i, p. 130, pi. v, figs. 2 a, b.

1879. PhoUdops, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat Histoi-y, p. 149, pi. xxi, figs. 1, 2.

1881. PhoUdops, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 284, j^l. xxi, figs. 1, 2.

1883. PhoUdops, Davidson. British Silurian Brachiopoda, Supplement, p. 216, pi. xvii, fig. 48.

1884. PhoUdops, Walcott. Palaeontology Eureka District, pp. 113, 114, i>l. ii, tigs. 6, 7.

1885. PhoUdops, Vebworn. Zeitschr. der Jeutsch. geol. Gesellsch., vol. xxxvii, p. 173.

Diagnosis. Shells small, patelliform, equivalve, equiconvex, inarticulate, un-
attached. Outline oval or subelliptical ; apex subcentral, excentric or marginal,
sometimes terminal and produced. Surface marked by strong, concentric, often
lamellose lines of growth, which are crowded on the posterior, and distant on
the anterior portions of the valves ; these are sometimes crossed by faint in-
terrupted radiating lines. In the interior, the surfaces of contact make a broad
smooth, flat or slightly convex border, somewhat broader in front than behind.
The muscular and visceral area occupies a sharply defined and very limited
space in the apical portion of each valve. In both valves it is of essentially
the same size and subtriangular in outline, the apex of the triangle pointing
forward and usually surrounded by a conspicuous callosity.

The ventral (?) valve bears two well defined central adductors occup^dng the
same relative position as in Cr.\nia ; these impressions are usually simple, but

156 PALjEONTOLOGY OF NEW YORK.

appear to be sometimes complicated by association with ill-defined scars of the
anterior muscles. The posterior adductors or divaricators are situated at the
basal angles of the muscular triangle, and are distant from the posterior mar-
gin. The linear parietal scars are very strong, the posterior being more or less
distinctly lobate, the anterior generally straight or rounding about the central
adductors. In the opposite or dorsal {?) valve the scars have essentially the same
arrangement; tlie anterior adductors, however, are separated by elongate median
scars (anteriors) which traverse the elevated callosity surrounding the anterior
margin of the area. The posterior scars are often more widely divergent than
in the other valve. Shell-substance calcareous and impunctate (?).
Type, Pholidops squamiformis, Hall.

OBSERVATroNS. This peculiar group of shells presents an interesting associa-
tion of features which, so far as known, is susceptible to slight variation. The
character of their muscular anatomy is distinctly cranioid, as seen in the
development of the two strong pairs of adductor scars, but the concentration
of the muscular impressions and the resulting removal of the posterior scars
forward from the margin is a feature not seen in any Crania ; added to this
is the usually sharp impression of the parietal wall which is rarely observable
in any of the inarticulates except the Trimerelloids. The posterior lobate
limb of this impression in Pholidops is suggestiv.e of the scalloped or sinused
arch seen in Lingulops,* but we should hesitate to suggest an analogy between
the two.

The depth of the muscular impressions in Pholidops, evidently an index of
the strength of the muscular bands, is a natural result of their concentration
within the confined visceral area, for by such a displacement a great advantage
in the closing of the valves is sacrificed.

In external features, outline and contour, there occur some noticeable varia-
tions. The typical species, P. squamiformis, with oval outline and subcentral
beak, represents the character of exterior prevailing among the species

* In discussing the genus Lingulops, we have indicated that the scar of the pai-ietal wall constitutes
the crown of the crescent and that thei'e is no satisfactoi-y reason for ascribing' to the crescent in Lingulops
one function, and to that in Tbimerblla another, as was done by Davidson and King.

BRACHIOPODA. 157

generally, appearing in the earliest known representative, P. Trentonmsis, and
enduring until the genus disappears in the Lower Carboniferous. Among the
forms which follow this type of exterior, it is often difficult to point out specific
differences, variations in internal features accompanying the slight external
changes in outline or convexity being as a rule difficult to establish. Thus the
forms, P. Trentonensis from the Trenton limestone, P. Cincinnatensis from the
Hudson group, P. squamiformis of the Niagara and Clinton groups, P. ovata
of the Lower Helderberg, P. hellula of the Lower Devonian of the Eureka
District, P. lepis of the Corniferous limestone, P. Hamiltonia of the Hamilton, and
an undetermined species in the Waverly, and also P. anliqua of the Beyrichien-
kalk of the Island of Gotland, present differences of slight value in any respect,
but each occurs at a distinct horizon and serves to characterize the faunas of
which they are respectively members.

A slight variation in external outline without essential change in interior
characters is seen in the elliptical species, P. ovalis of the Niagara and in P.
implicata of the Wenlock; and it is probable that these American and European
forms are identical. A more extreme variation appears in the species, P. termi-
nalis of the Oriskany sandstone, P. calceola of the Corniferous, P. Imguloides and
P. oblata of the Hamilton, where the apex is terminal and produced, the con-
centric striae on the posterior limb of the shell making a sort of cardinal area.
This extended umbo is solid and it remains to be ascertained whether it occurs
on both valves alike.

In regard to the nomenclature of the two valves in Pholidops, the terms
pedicle and brachial are inapplicable here as in Crania, on account of the absence
of any pedicle-aperture in the mature shell. The conventional designations
ventral and dorsal, which are virtually misnomers in their application to the
brachiopoda, may serve to indicate a means of comparison with the attached
(" ventral ") and free (" dorsal ") valves of Crania. With the latter, that valve
in Pholidops is homologous which bears the median pair of narrow, elongate
scars, traversing the anterior apex of the muscular callosity ; these scars
representing the distal anteriors found in the free valve of Crania (probably
the anterior insertion of the brachial muscles), and shown very distinctly by

158 PALEONTOLOGY OF NEW YORK.

Davidson* in the " dorsal " valve of the free species, Crania {Pseudocrania)
divaricata, McCoy. In the opposite valve of Pholidops these scars do not
appear, and the interior margin of the callosity is uninterrupted In certain
species, particularly those of large size which have.heen found as internal casts,
the whole muscular area of the ventral (?) valve appears to be occupied by the
scars of the anterior adductors (see Plate IV i, figs. 26, 36). The fact that in
these cases the other muscular and the parietal scars are not defined is probably
due to imperfect preservation.

The substance of the shells of Pholidops is calcareous and apparently im-
punctate. On account of their extreme tenuity it has been impossible to make
satisfactory sections, but there appears by magnification of the surface no evi-
dence of punctation. Should an impunctate character be demonstrated it will
be another important respect in which Pholidops differs from Crania.

This group of shells was noticed as early as 1820 by Schlotheim, who, by
the designation Patellites (P. antiquus of the Gotland Upper Silurian lime-
stone) implied its relationship to Patella. Sowerby, in 1839, essentially
coincided with this opinion in referring an English species to Patella (P.
implicata). Thereafter, until 1859, the American species were placed under the
genus Orbicula, a name which at that time had come to include a great variety
of heterogeneous brachiopods, now mainly referred to Crania and Orbiculoidea.
McCoy, however, in 1859, considered the English species congeneric with the
ScHizoTRETA of KuTORGA, and, not recognizing the priority of the latter name,
placed both in D'Orbigny's genus, Orbiculoidea. Salter, in 1859, and David-
son as late as 1866, referred P. implicata, Sowerby, to Crania, and though the
latter author in 1883 corrects this reference and recognizes the term Pholidops,
no modification was suggested of the figures given of the interior of this
species in the British Silurian Brachiopoda (pi. viii, figs. 15, 16 a), which are
radically incorrect in representing the valves with posterior marginal muscular
scars. In 1859, in a revised list of the fossils described in the first two volumes
of the Palaeontology of New York, the term Craniops was proposed for the

* British Silurian Brachiopoda, pi. viii, figs. 11, 11 a, 12 a.

BRACHIOPODA. 159

Niagara species Orbicula ? squamiformis, though without further definition, hut
in Volume III of the Palaeontology, published the same year, the genus was
illustrated and defined under the name of Pholidops, the term Chaniops being
unaccountably overlooked.

The relations of this genus to Pseudocrania, McCoy, and Pal^ocrania, Eich-
wald, have been elsewhere discussed.

Species of Pholidops are often abundant in American palaeozoic faunas, their
first appearance being, as already noticed, in the Trenton, and their latest
known representative in the Bedford shales. It has already been observed that
there exists a close specific similarity in some of tlie forni.s belonging to widely
separated faunas, e. g., P. Trentonensis, P. Cincinnatmsis, P. squamiformis, P. ovata,
P. HamiltonicR and P., sp. (?), from the Trenton, Hudson, Niagara, Lower
Helderberg, Hamilton and Waverly groups respectively, but it is indispensable
to recognize them as distinct species. In strong contrast to this general preva-
lence of Pholidops in America, is the evident paucity of its representation in
Europe, where occur only the P. implicata, in England, and the same species
with P. antiqua, in Gotland, the former being regarded by some authors as
synonymous with the latter.

160 PALEONTOLOGY OF NEW YORK.

NOTE TO PAGE 128.

The genus Orbiculoidea of D'Orbigny was first defined and exemplified in
tlie Prodrome de PalL-ontologie, vol. i, p. 44, the date of this work being 1850,
not 1849. Dall is in error in stating that Orbicula Morrisi, Davidson, is the
first species mentioned under the diagnosis quoted. D'Orbigny here gives three
species in the following order : 0. Forbesi, Davidson, 0. Morrisi, Davidson, 0.
Davidsoni, D'Orbigny. As no species is specially designated as the type of
the genus we are compelled to assume these three as types in their order and
upon tlieir merits. It is shown on page 136 that the first of these, 0. Forbesi,
Davidson, is unquestionably congeneric with Schizotrefa elliptica, Kutorga,
Kutorga's genus having been established in 1848. As this species, therefore,
can not be used as the type of Orbiculoidea, we must assume the second species
as tlie typical representative of the genus, and upon this is based the distinc-
tion throughout the foregoing pages in the use of this term Orbiculoidea by
D'Orbigny and by Davidson. At the place cited in the " Prodrome " the date
" 1847 " stands after the name of the genus. The explanation of its use
appears upon page lix of the Introduction, and the date of publication of the
work renders its adoption untenable.

CONCLUSION.

The consecutive treatment of a group of organisms whose natural relations
can be properly expressed only by diverging lines or ramifications from some
common stock, fiiils to indicate satisfactorily the relations of each part of the
group with every other part. These must be pointed out by themselves after
the characters of the various subdivisions have been described.

To avoid difficulties and unnecessary discussion, no recognition has thus far
in this work, been accorded to family groups. The reasons for this will appear
in the following. On the other hand it has seemed judicious, in order to
make the generic discussions, as far as possible, homogeneous, to use as many
terms of this value as are in any way justifiable. The future will undoubtedly
demonstrate that some of these genei'ic groups are still too broad.

To regard the genus Lingula. as taxonomically at the base of the brachiopoda,
is a matter of custom. Against this position, nearly every feature of anatomy,
development, and geological history is a protest. The muscular system of
Lingula is extremely complicated, more so than that of any other of these
inarticulate forms, and probably more than in any other generic group in the
order of brachiopoda. In dealing with the fossil forms, the details of muscular
arrangement are found to be frequently much obscured ; we can not always be
sure of our data, and under such conditions, it becomes important to subordi-
nate apparent variations in the arrangement of muscular scars, as an element
in establishing generic relations, to some feature subject to less variation from
mode of preservation. This feature of paramount importance, we believe will
be found in the character of the pedicle-passage.

Among the inarticulates, its variations in position and structure are extreme,
and must have been accompanied by or have necessitated material changes in
internal anatomy. On such a basis alone, Lingula, which has the posterior

162

PALEONTOLOGY OF NEW YORK.

margin of l)otli valve.s modified I'or tlie passage of the pedicle l>et\veen them,
may take a position near the base of the system, and its elaborate muscular
apparatus may establish it in such a position as a comprehensive type or point
of departure for many derivatives.

fi. llinj;c'-l('i-th i<\' lii':u'lii;il v;il\c.

h. Hinge-tfulh cil' iii;<liclt'-v.-ilve.

f. Spniich'cular i)latc of br;tclii;il

valve.

ft. Median tentacle.

/. Parietal bands.

ff. Body oavit\'.

h lAvcv.

k- Hepatic clianiber of .-stomach.

I. Intestinal cliaml>er of .stomach.

m. Intestine.

n. Anus,

o. Mouth.

p. Muscles (priinai-y).

q. l.ophophore.

r. Posterior unpaired nniscle.

V. Pallial sinus.

in Its opening into the bo'ly cavity

Kmbryonic >tage.s of Liiujida iiiiramhiiita, .Siimpson {,— (JluttUlui Amhliiii-li, Brodcrip).

After BuooKS.
Fi<i. ".'). Dorsal view of the youngest larva observed. X 250.
Fio. 76. Dorsal view of a somewhat older embryo. X '-5".
Fig. 77. Ventral view of an individual soon after beoondng sedenlary. ii» indicate^ the cilge of I he larval shell.

The eml)ryological history of Lingula, as elaborated by Brooks,* for L.
pijramidata {=^ Glottidia Audebarti), has an important bearing upon the taxonomic
position of this group. The author has shown that the shell in its earlier stages,
has a subcircular form, and that the posterior opening for the pedicle is as fully
developed on one valve as on the other ; further, that the muscular bands first
to appear are a great posterior or umbonal, and two simple transverse bands
crossing the interior cavity (but not each other) near the oesophagus. The lat-
ter are regarded by Brooks as representing the muscles h, j, k and /, of the
mature animal (see figs. 6, 7, page 10). All these features are apparent in
shells of the obolelloids ; the subcircular valves, the pedicle-passage, sometimes

Ohesapoake Zoological Lahoi'atory ; Scientific Ileault.s of Ses.sion of 1S7S.

BRACHIOPODA. 163

clearly developed in tlie brachial as well as in the pedicle-valve, a large cen-
tral (umbonal ?) muscular scar, and conspicuous, undifferentiated lateral scars.

The fact that the culmination of the obolelloid type was attained in fiunas
where Lingula is not yet known, fortifies the view that Lingula has been directly
derived from this source. In Lingulella and Lingulepis may be found impor-
tant connecting links, in which the external form of Lingula is associated with
the muscular arrangement and the narrow pedicle-slit of the obolelloids. These
two genera are also forerunners of Lingula.

By the attainment of the linguloid ensemble, a combination of characters was
produced which was capable of adapting itself to all conceivable changes in its
surroundings to an extent never recurring in the organic world. But while the
development along the linguloid line has continued, as we believe, from early
Silurian to the present time, modifications of this type were not infrequent.
From Lingula we may depart in many directions. A gradual increase in the
secretion of testaceous matter about the insertions of the muscular and parietal
bands, carries eventually to an extreme the development of median and lateral
septa. One phase of this extreme, in which the septa are alike in both valves,
is attained, in Dignomia, as early as the Devonian; another, with some diversity
in the septa of the opposite valves (and quite plausibly in the direct line of
derivation from Dignomia), appears first in the Mesozoic, .and has continued to
the present in Glottiuia. The numerous forms in whicli the septa are more
or less developed without attaining the condition in Dignomia or Glottidia
are better left within the proper limits of Lingula.

Again, the elevation of the anterior edges of the testaceous deposits about
the bases of the central and lateral muscles, probably due, as we have elsewhere
suggested (see pages 46-55), to displacement of, and pressure against the liver,
has induced first, the thickening of the entire area of muscular implantation,
followed by the gradual excavation of this solid plate and the formation of a
more or less vaulted platform. Thus was begun the line of variations con-
secutive through LiNGULOPS and Lingulasma, the extreme of wliich is reached
in Trimerella. In the later Silurian sea the conditions appear to have been
especially favorable to the rapid development of these platform-bearing species,

164 PALEONTOLOGY OF NEW' YORK.

and the abrupt extinction of the entire group with the close of the Niagara-
Wenlock period constitutes one of the most striking features in their history.

In Barroisella a considerable variation from Lingula is found in the char-
ter of the internal markings, accompanied by the development of the deltidial
callosities to such a degree as to indicate their specialization for purposes of
articulation, and it is here that we find one of the most striking of the few
instances observed among the brachiopods, of an evident tendency to span the
interval between the so-called inarticulates and articulates. Barroisella sub-
spatulata of the Genesee fauna affords the last phase in the development along
this line ; it had been preceded in Silurian faunas by the Lingula ? Lesueuri, a
form which has the articulating processes of Barroisella combined with the
septal characters of Dignomia or Glottidia.

Future investigation may show that the little-known Spondylobolus is a
similar resultant which has come by the way of Obolella. The same tendency
to the development of articular processes in the pedicle-valve is also observable,
though to a less degree, in Trimerella and Monomerella, while the inception of
a cardinal process in the opposite valve has repeatedly manifested itself (See
note on page 1.)

The immediate lines of derivation of, and departure from Lingula are ex-
pressed in the following diagram :

(.S|ioiiclylol)oliis) ? - - BaiToisella

{ Lingula f Lesxieuri)
Tomasiriii /

Digiioinia Glottidia ^

>

Ling-ulepis / Ling-iilops LiHf,'-ulasina fTrimerella

^^^-^ ■{ Monomerella
Glossina -■ ,' r>u- i i

Dinobohis LRhinobokis

Returning to the genus Obolella, we find it also an important point of
divergence.

BRACHIOPODA. 165

As suggested above, certain linguloid characters, in which form and the
structure of the pedicle-passage are paramount, have departed toward Lingula
1)\- tlie way of Lingulella. Another combination of linguloid features, in
which the muscular scars are of primary importance, but the form still obolel-
loid, is represented by the genus Obolus. Here the muscular bands have
become specialized to such a degree that in the pedicle-valve they approach
closely to Lingula, while in the other they retain more distinctly the obolelloid
character ; moreover, the subcircular form and the persistence of the pedicle-
groove on both valves are features of Obolella.

Obolds, therefore, is a more specialized form than Obolella and less so than
Lingula. The aberrant Neobolus appears to hold intermediate structural rela-
tions to botli Obolus and Obolella, except in the existence of a strong cardinal
pi-ocess in the brachial valve, a feature indicating progress in this line of
derivation, toward characters of the articulate brachiopods.

The typical combination of obolelloid characters is continued, without essen-
tial variation, into the genera Leptobolus and Scumidtia, while Paterula,
whose structure demonstrates its close alliance with Leptobolus, presents anew
feature of great importance in its minute, incised, marginal pedicle-aperture.
In ScHizoBOLUS we find the same features superinduced upon the substantially
unaltered muscular scars of Obolella.

While discussing the origin and development of the platform in the inarticu-
late brachiopoda, we have referred to the fact, that Obolus, in having its
muscular scars excavated, as in Lingula, and not elevated on a central thicken-
ing, as in the other forms constituting the linguloid line of development toward
Trimerella, holds the same relation to the genus Elkania, as does Lingula to
Lin(;ulops. Further, that Elkania represents, by virtue of this variation, an
important progress in the development of trimerelloid characters along the
obolelloid line, connecting with Trimerella by way of Dinobolus. There is no
single feature in the entire group of the edentulous brachiopods so striking as
the great platform in Trimerella and its allies, and it is rarely that so beautiful
and well-established an illustration of the attainment of such a remarkable re-
sultant along two distinct lines of development can be presented.

166

PALAEONTOLOGY OF NEW YORK.

Tlie immediate variations from the obolelloid stoclc, may be expressed as
follows :

Schinidtia ■

Pateiula

Schizobolus

->

Lingulella -

I
Lingnlejiis

Lingula

Neobolus

I
Aulonotreta

OV)0lus-

-Elkania-

■ Dinobolns

With the inception of a marginal pedicle-aperture taking the form of a slit
in the substance of the shell, begins a series of variations which eventuate in
SiPHONOTRETA and Orbiculoidea. The association of this feature with the
distinctive characters of the obolelloid stock has been observed only in the
genera Schizobolus and Paterula, more definitely in the former. Its
assumption appears to have been accompanied directly by an elevation
of the posterior margin into a vertical, somewhat specialized area, suggesting
the true cardinal area of the articulates. Thus, in the genera Kutoruina and
its representative in the " Obolus beds " of the Salt-Range of India, ScHizo-
PHOLis, the subapical posterior slope, often incurved in Kdtorgina, is divided
for its entire height by a triangular opening. In Volborthia, Iphidea, and
AcROTRETA, essentially the same features are present, save that the pedicle-slit
is represented by a ridge in Volborthia and Iphidea, and a furrow in Acrotreta,
terminating in an aperture at the apex of the shell (Volborthia ?).

It has already been observed, that the explanation of these pedicle-characters
and their apparent differences, may be found in the mode of growth of the shell.
In KuTORGiNA and Schizopholis, the mantle of the shell or the pedicle itself has
failed to secrete testaceous matter behind the aperture as growth advanced, thus

BRACHIOPODA. 167

leaving, from youtli to maturity, a triangular opening extending the entire
width of the area. In Volborthia, Iphidea, and Acrotreta, tlie ridge or furrow
indicates the modification of the surface made by the aperture. In Acrotiiei.e,
the posterior slope is again less defined, and the progress of the foraminal scar
not distinctly marked upon its surface. In these features the passage to
Siphonotreta is imperceptible, while in Schizambon, the close ally of Sipiion-
otreta in most respects, the position of the aperture is in front of the Ijeak,
and its advance with growth leaves between it and the apex a conspicuous
furrow crossed by concentric lines of accretion. This we regard as an extreme
of development in the character of the pedicle-passage, a point which is not
passed by these shells.

The enclosure of the pedicle-slit, leaving only a circular perforation for the
passage of the arm of attachment, appears to have been unaccompanied, as lar
as our evidence reaches, by any essential variations in internal conformation
in the genera Volborthia, Iphidea, Chonotreta and Acrothele. In Acrotreta
there is an elevation or mammiform swelling about the internal opening of
the sipho, which necessarily gives the passage the character of a short tube.
In Linnarssonia and Discinopsis this internal swelling becomes more extremely
developed in lateral extension, while in Siphonotreta it is expressed in a greater
longitudinal development, producing a well developed tuh(!. The muscular
impressions of this group of genera are so imperfectly understood that it is
impossible to correlate them satisftictorily, l)ut their biological relations, as
far as expressed in the characters of tlie pedicle-passage, may be represented
by the following diagram :

rKiitorgiiiH I I

Obolnna-I.cptobolus-P.-.tcrula- I -i I [-Vollioithi.il ,'T,inn.-irssonia\

I I Ischi/.opholisJ I [-Acrotreta' .^Siplionotrul.i-.Sclii/.amlioii

Sclimkltia Scliizobohis I Iplii.ioa J I Acrotliole

r

(Disrinolepis)

C'lioiiiitrfta

This scheme is not intended as an expression of the derivation or geological
succession of these genera. Leptobolus and Schmidtia follow Obolella in the

168 ■ PALjEONTOLOGY OF NEW YORK.

liiunas of the later Lower Silurian, associated with Paterula, while Schizobolus
presents the only association of obolelloid characters known in Devonian faunas.

KUTORGINA, SCHIZOPHOLIS, VOLBORTHIA, IPHIDEA, ACROTBETA, AcROTHELE, LlNNARS-

SONIA aiicl DisciNOPSis belonged in a general sense to contemporaneous faunas
of primordial age, while Chonotreta, Schizambon and Siphonotreta are from
the Lower Silurian.

We may have to seek the source whence these numerous closely allied pri-
mordial groups are derived, in some earlier comprehensive stock of which we now
have no knowledge. The ages preceding the Silurian afforded abundant time
for a tendency to variability to express itself; how far the apparent order of
development will harmonize with the actual order of succession in the subor-
dinate faunas of this time, must await demonstration.

The marginal pedicle-slit has followed still another line of development.
The simple incision of the margin as in Paterula, becomes in Schizocrania a
wide fissure extending to a subcentral beak, i.e., for nearly the radius of the shell.
Our observations upon the embryonic stages of Orbiculoidea have shown that
the fissure, in early conditions of growth, is of similar character, its margins
straight and divergent, but subsequently uniting to form the narrow pedicle-
groove and tube. In Trematis, the margins of the slit are curved, but they
never unite at the outer extremity, while in the genus OEhlertella of the
Waverly group, the margins are more nearly straight, but the incision always
open.

The apical accretion in the foramen of Schizocrania, the structure of which
has been alluded to in the preceding pages, finds its homologue in the allied
genera. In Trematis it is less distinctly developed than elsewhere, but in
GEhlertella its tripartite arrangement into a central groove for the passage of
the pedicle, and two strong lateral walls enforcing the same effect, brings it
into precise agreement with the structure of the groove in Orbiculoidea and
Schizotreta, save that in the former the posterior walls of the slit have united
at maturity.

BRACHIOPODA. 109

Furthermore, from Scuizocrania to Q^hlertella and Schizotreta, there is a
gradual increase in the degree of depression of this apical area. In tlie first
genus this is very slight, the part often appearing to l)e in tlie plane ol" the
valve ; in Trematis the entire sul)apical area is depressed without any marked
development of this feature, while in (Ehlertella pleurites we find it to be ex-
ceedingly depressed, so that if the outer margins of the slit were united, a
broad tubular passage to the interior would remain.

In general effect, there is a striking resemblance in the external appearance
of the pedicle-area in Orbiculoidea and Schizotreta, and in Schizambon. This
resemblance is, however, superficial, and can not be allowed to bring the ex-
tremes of development along dilVerent lines into a very close relationship.

In Schizambon (S. fissus), the pedicle-groove lying in front of the beak, is
crossed by the interrupted growth-lines of the shell-surface, while in Orbicu-
loidea, the tripartite subdivision of the groove, never encroached upon Ijy the
concentric growth-lines, invariably maintains its posterior position.

In DisciNiscA, the same tripartite division of the pedicle-area gives evidence
of relationship derived from Orbiculoidea, although the foramen has changed
from an oblique to a vertical position ; while, in Discina, the tubular cliaracter
of the foramen is retained at the expense of the suljdivision of the groove and
has become inverted in its direction, so that the pedicle is protruded posteriorly
instead of anteriorly or toward the apex as in Orbiculoidea. The evidence
afforded by the developmental stages of Orbiculoidea demonstrates con-
clusively the primary taxonomic position of Scuizocrania in this group.

Wherever there occurs a complete atrophy of the pedicle, it necessarily
induces an important modification in the interior of the shell. In the genus
Crania, where the whole function of the pedicle is effected by the substantial
attachment of the lower valve, the opening and closing mu.scles are allowed
greater freedom of action and their attachment to each of the two valves is
of so similar a character that it is frequently a difficult matter to determine,
from these features alone, whether a given valve is the upper or the lower.
The arrangement of the muscular bands is essentially as in the discinoids, with

170 PALEONTOLOGY OF NEW YORK.

the pedicle-muscles and the modification produced by the presence of the
pedicle-passage, abstracted.

In Crania and Craniella, where the sedentary habit appears to be no
more than a specific character, there is little vai'iability in the nature of the
muscular scars ; in the genus Pholidops, however, the shells of which are
invariably free, there is a concentration of the muscular scars at the middle of
the valves, the strength of the impressions indicating that considerable power
was required to keep the valves closed, with the muscles placed at this dis-
advantageous position.

SUPPLEMENT

BRACHIOPODA INARTICULATA.

DESCRIPTIONS OF NEW SPECIES

REFERRED To IN THE PKECEDINU PAGES OR ON THE AC'CoMl'AN VINi; PLATE8.

LiNGULA COMPTA, sp. IIOV.

PLATE I, KKj. 1G.

Shell very narrow, with lateral margins nearly parallel lor most of their length ;
the anterior margin transverse and the posterior less abruptly rounded.
Shell-substance thin. Surface marked by fine concentric striae.

The interior of the brachial (?) valve bears two strong lateral muscular
ridges which meet in the median line at about one-third the length of the
shell from the anterior margin. A narrow median I'urrow extends from just
behind the center of the valve nearly to the anterior margin. Length of this
valve, 9 mm., greatest width, 4.5 mm.

This species is allied to L. dmsa, Hall, but differs in its narrower form and
thinner shell.

Hamilton group. Tichenofs Gully, Canandaigua Lake, N. Y.

LiNGOLA SCUTELLA, Sp. nOV.
PLATE I, FIG. 30.

Shell broad, subquadrate ; lateral margins parallel for a short distance, but soon
rounding to the extremities, which have about equal curvature. Length to
width as 2 to 3. Surfiice covered with more or less distinct concentric lines
and wrinkles. The interior of the original valve, a cast of the interior,

172 PALEONTOLOGY OF NEW YORK.

shows a broad central elevation, corresponding to the muscular impressions,
and converging ridges over the pallial region, representing the vascular
sinuses. Fine radiating lines are also .visible over the anterior region.
Length of the valve, 12 mm., greatest width, 8 mm.

Chemung group. Alleghany counUj, N. Y.

LlNGULA FLABELLULA, Sp. nOV.
PLATE I, FIGS. 33, 34.

Shell large, subtriangular ; lateral margins diverging from an acute apex,
rounding broadly at about two-thirds the length of the shell, to the slightly
transverse anterior margin. Length to greatest width as 6 to 7. Surface
convex, sloping more abruptly to the sides than to the anterior margin ;
covered with low, rather taint and distant concentric lines or wrinkles. Shell-
substance comparatively thick, showing fine radiating lines on the inner
laminae. Length of the largest specimen observed, 42 mm., greatest width,
36 mm.

Waverly group. Scioloville and Beren, Ohio.

LiNGULA PABACLETUS, .Sp. nOV.

(See page 12. tiff. 8.)

Shell moderately large, broadly spatulate. Posterior margins diverging from
an acute beak, rounding slowly to tlie sides of the shell where the curve is
less ; the interior margin is subcircular, rarely transverse. The greatest
width of the shell is in front of the middle and the proportions of length to
greatest width are as 2 to 1.3. Surface ornamented with distant, concentric
wrinkles between which are exceedingly fine concentric striae. On the in-
terior tlie valves have a notably broad margin of contact. The internal cast
sometimes shows this to he broadest at the middle of the anterior margin;
faint radiating striae are also observable on this cast. The muscular and
vascular impressions of the interior are frequently well defined, as described
on the page above cited. Length of the original specimen, 16 mm., width,
1 1 mm.

Waverly group. Cui/ahoga shales, Chardon, Ohio.

BRACHIOPODA. 173

LiNGULA T^NIOLA, llOIU. IIOV.
Lingula latnellata. Hall. Palasontolog-y N. Y., vol. ii, i>. iiii, pi. xx, t\g». 4 a, h, c.

(See page IS.)

Lingula lingulata, sp. nov.

PI.-VTE IV K, FIG. a.

Shell elongate-subquadrate, having somewhat the form ol' Lingula oblata, Hall.
Valves very slightly convex. Distinguished Irom other species by the
peculiar deflection of the anterior portion of the shell con.siderably below
the plane of the lateral margins.

Clinton group. Near Hamilton, Ontario.

LiNGULOPS Granti, sp. nov.

I'LATE IV K, FIGS. U. 1:1

Shell small, linguloid in external aspect. Outline elliptical, subaouininate
at the posterior extremity. External surface marked by faint, elevated,
equidistant concentric lines. Margin of contact broad and conspicuous about
the entire periphery. On the interior of the pedicle-valve the margin is
broadest beneath the beak and slightly grooved on its posterior edge for the
passage of the pedicle. The central and lateral muscular scars are elevated
on a well developed platform, the ante-lateral margins of \vhich meet each
other at an acute angle. In the brachial valve the posterior margin is also
broad and faintly grooved, the platform more conspicuously developed both
in length, width and height than in the other valve, while the nniscular scars
have essentially the same arrangement. In neither valve do the specimens
at hand afford evidence of the arched parietal impressions seen in the other
species of the genus. Length of an average specimen, 5 mm., width, 3 mm.

This species differs from L. Whitjieldi and L. Norwoodi, not only in the absence
of the parietal scars, but also in the development of the muscular area of the
pedicle-valve into a distinct platform, and in the absence of the anterior longi-
tudinal septum in the pedicle-valve.

Niagara group. Hamilton, Ontario.

174 PALEONTOLOGY OF NEW YORK.

MONOMERELLA GeEENII, sp. IIOV.
PLATE IV II, FIGS. 5-10.

Shell elon.aate-siibovate. Valves comparatively shallow ; shell-substance
relatively thin. Surfaces of contact very broad, especially toward the
posterior portion of the shell. Pedicle-valve with an erect but not high
cardinal area, whicli is continuous with the broad margins. Umbonal cavi-
ties very short, rarely reacliing to tlie hinge-line and sometimes scarcely more
developed than in Dinobolus. Cardinal slope well defined and divided by a
deep longitudinal groove. Cardinal buttress faint. Platform scarcely devel-
oped ; the scars upon its surface usually faint, but the lateral impressions are
sometimes sharply defined. Crescent and terminal scars generally distinct.
Pallial sinuses usually discernible. Brachial valve with a low, rotund beak
and transversely striated area. Umbonal cavity deep. The deep groove of
the crescent is followed within by a sharply elevated ridge extending for the
entire length of the cardinal line ; terminal scars generally deeply impressed
and apparentl}- compound. Platform represented only by a median thicken-
ing of the nuiscular impressions, having the characteristic V-^^^'i-ped outline
and sometimes divisible into the component scars. From the anterior ex-
tremity of this muscular area two diverging ridges pass toward the anterior
margin ; these may be connected with the pallial sinuses.

This shell is readily distinguished from all other described species by the
general tendency toward suppression of the platforms and muscular scars, the
broad surface of contact, and the diverging anterior furrows of the brachial valve.

From the dolomites of the Niagara group, between Cedarburgh and Grafton,
Wisconsin.

MONOMERELLA KiNGI, Sp. nOV.
PLATE IV D, FIGS. 1, 2.

Shell subcircular or longitudinally oval. Pedicle-valve probably with a low
cardinal area, as far as may be judged by the size of the casts of the umbonal
cavities, which are quite short, mammiform, not extending to the cardinal
line. Cardinal buttress strong, produced as a septum nearly to the anterior
edge of the platform. Platform well developed, broadly V-shaped ; anterior
wall vertical, not excavated; surface marked by strong impressions of mus-

BRACHIOPODA. 175

cular attachments. Crescent distinct, terminal scars very prominent.
Brachial valve with the umbonal region nnich thickened ; the platform
sharply V-*^li'ip6tl> its anterior wall beini;' considerably excavated to Ibrm
imperfect vanlts ; the wliole elevation is situated somewhat further forward
than the opposite valve. A faint longitudinal septum extends a short dis-
tance forward from the apex of the platform. Crown of the crescent faint;
terminal scars as in the pedicle-valve.

From tlie magnesian limestone of the Niagara .group, near Cedarburgh, Wis-
consin, in association with Diiiobolus Conradi, Monomer ella prisca and M. Greenii.

MONOMERELLA OrTONI, sp. HOV.
I'LATE IV c, FIGS, li, 15.

Pedicle-valve large, with a high cardinal area, which is gently incurved longi-
tudinally and crossed by lamellose growth-lines, upon which the evidences
of the deltidial ridges are extremely faint or altogether wanting. Umbonal
cavities conspicuous, but much shorter than is usual in M. prisca. Cardinal
slope large, triangular and divided by an axial furrow. Cardinal buttress
broad at the base but not especially prominent. Platform apparent only at
its anterior edge where it has a broad anterior slope. Crescent well defined
beneath the hinge-line ; terminal scars very prominent ; central, lateral and
anterior impressions discernible on the platform. Pallial sinuses very strong,
the outer ramifications from which are distinctly seen.
Brachial valve unknown.

From the Niagara dolomitic limestone, at tlu; Rising Sun quarries, Wood
count)/, Ohio.

MoNOMERELLA EgANI, sp. IIOV.
I'LATE IV c, FIG, 16

Brachial valve with an unusually high cardinal area, indicating a quite ele-
vated beak. This area is strongly striated transverseh', and bears two faint
longitudinal depressions corresponding in position to the deltidial ridges of
the pedicle-valve. It is continued laterally nearly to the middle of the
margins. Crescent very narrow over the crown, lying close upon the car-
dinal line ; at its turn forward it is developed into a deep, narrow, elongate

170 PALEONTOLOGY OF NEW YORK.

muscular scar, which is continued into a broader terminal impression. Plat-
ibrm sharply elevated at its anterior edge, sloping rather abruptly backward.
Its surface bears the usual tripartite arrangement of the muscular scars.
Anterior longitudinal septum distinct. From directly behind the crescent
to the central muscular impressions, is a veiy broad, smooth, lunate slope,
occupying the position of the simple umbonal cavity usual in this valve of
MoNOMERELLA, and presenting the appearance of an abnormal deposition or
callositv.

Though represented by a single specimen only, this form shows features not
elsewhere observed in the genus, viz., the great development of the cardinal
area, the composite character of the muscular impressions terminating the
crescent, and the broad posterior slope.

From the Niagara group, near Grafton, Wisconsin.

Rhinobolus Davidsoni, sp. nov.

PLATE IV H, FIGS. 10-12.

Shell with a circular outline, except for the prominence of the beak. Pedicle-
valve with a moderately high, acuminate cardinal area, upon which the
central area, the deltidial ridges and areal borders have each about the same
width. Cardinal slope short; crescent sharply defined ; terminal scars dis-
tinct. Platform broadly V-^haped, sloping less abruptly backward than in
R. Gallensis. Pallial sinuses faint. Brachial valve with marginal beak and
inconspicuous area. Crescent more prominently developed than in the
opposite valve, transverse over, the crown as in Dinobolus; terminal scars
large. Platform more sharply angulated than in the pedicle-valve and some-
what more elevated, bearing conspicuous lateral and anterior scars. Longi-
tudinal septum not pronounced. Pallial sinuses quite distinct.

This species is based upon internal casts of opposite valves, which are in
entire harmony with each other and are readily separated from Dinobolus Con-
radi and the various species of Monomerella associated with them at the same
locality. It is distinguished from the forms referred to Rhinobolus Galtensis,
Billings, by its more circular outline, less elevated pedicle-umbo, inconspicuous
brachial umbo, and broader, though less sharply elevated platform.

Niagara group. Near Grafton, Wisconsin.

BRACIIIOPODA. 177

SiPHONOTRETA (?) MiNNESOTENSIS, Sp. nOV.
PLATE IV, FIGS. S7, 33.

Shell subovate in outline. Pedicle-valve more convex than the brachial, slishtlv
flattened along the median line, slopino; with ecjual convexity toward the
lateral and anterior margin.s. Foramen apical (.'). Brachial valve depressed-
convex, somewhat elevated about the umbo. Surface covered, in the um-
bonal region, with fine, anastomosing and gently undulating concentric lines,
which, in the later portions of the shell, are finely granulose or serrated ; at
about one-third the length of the shell coarser varices of growtli appear,
between which the finer lines are retained. Surface covered with hollow
spines of various sizes, which appear to have been most closely set over the
umbonal region of the pedicle-valve. Here, where the growth-lines are
absent, the spine-bases in the original specimen are large and all of about
the same size and are disposed without order. Over the other portions of
the shell the spines are set along the edges of the varices, small and large
being indifferently mixed. The bases of the spines make annular swellings
on the interior of the valves. The length of the original specimen is 15
mm., width, 12 mm.

Trenton limestone. Minneapolis, Minnesota.

Orbiculoidea (Schizotreta) ovALis, sp. nov.

PLATE IV E, FIGS. 4,0.

Shell subelliptical in outline. Valves with apices situated a little behind the
center. Lower valve with the apex erect or inclined slightly forward. Ex-
ternal foraminal groove narrow, extending for about one-half the posterior
radius of the valve. Surface about the foramen convex, but elsewhere slightly
depressed in its slope from apex to margin. Upper valve more elevated than
the lower, apex inclined backward, posterior slope gently concave. Surface
marked by elevated nearly equidistant concentric strife. Shell-substance
thick, the inner laminae showing fine radiating lines over the anterior region.
Length of the original specimen, 8 mm., width, 6 mm., thickne.ss through
the apices of the conjoined valves, 3 mm.

Trenton limestone. Middleville, N. Y.

178 PALEONTOLOGY OF NEW YORK.

Orbiculoidea numulus, sp. nov.

PLATE IV E, FIG. 14.

The original specimen is a lower valve, having a nearly circular outline.
The apex is subcentral, elevated and directed anteriorly. The external groove
of the Ibramen is moderately broad and extends one-half the length of the
po.sterior radius. The posterior slope is convex while the anterior is depressed
or slightly concave. Surface smooth about the apex, thence outward marked
by a few distant, elevated, concentric lines or ridges, between which are
numerous Hue concentric lines. Length and width, 12 mm.

Lower Helderberg group (Waterlime). Marshall, N. Y.

Orbiculoidea Herzeri, sp. nov.

PLATE IV E, FIG. m; and PL.VTE I Vf, FIGS. 9-13, 30.

Shell subcircular in outline. Upper valve with an excentric apex, situated
less than one-fourth the length of the shell from the posterior margin, and
directed l)ackward. Surface gently convex, sloping evenly forward from the
apex, but abruptly depressed on the post-apical region. Lower valve with
the apex much nearer the center; shell almost tiat. Pedicle-aperture, in the
primary stages of development, a triangular opening extending from the apex
to the margin; this gradually closes with advancing growth, the external
gi-oove at maturity extending from one-half to two-thirds the length of the
posterior radius of the valve. On the interior, the groove is frequently more
or less enveloped by the development of testaceous deposits. Surface of both
valves ornamented by crowded concentric lines and wrinkles. The internal
surface of the lower valve sometimes shows fine radiating lines and faint
vascular sinuses. Length and width of an adult individual, 14 mm.

Waverly group (Cuyahoga shales). Berea, Baconshirg and elsewhere, Ohio.

Lindstbcemella aspidium, gen. et sp. nov.

PLATE IV E, FIG.S. 25-28.

This species is readily distinguished from Orbiculoidea {Ramerella) grandis, its
associate in the fauna ol' tlu; Hamilton shales, and the only form with which

BRACHIOPODA. 179

there i^ danger of confoundhig it, by tlie convex pedicle-valve, the distant,
elevated, concentric surface-ridges, which have a peculiar unduhition as they
approach the margins of the foramen. The internal characters of the shell are
at once distinctive. (See discussion of these features on page 134.) Length
and widtli of a mature specimen, 50 mm.

Hamilton group. Leonardsville, Hamilton, Darien and Canandaigua Lake,
N. Y.

SCHIZOCRANIA ScHUCHERTI, sp. nov.
PLATE IV G, FIGS. Sl-S.'!.

Shell small, usually found unattached ; marginal outline subovate. Surface
of pedicle-valve flat or slightly concave; concentrically striated. Pedicle-
aperture broad and sharply triangular. Brachial or upper valve strongly
convex, often laterally compressed. Umbo full and rotund, incurved at the
apex, which is almost, but not quite marginal. Surface covered by numerous
simple, sharply elevated, uninterrupted stride, frequently crossed by concen-
tric wrinkles. On the interior of this valve only the strong posterior
muscular impressions are distinctly shown.

Hudson River group. Cincinnati, Ohio.

ScHizocRANiA (?) Helderbergia, sp. nov.

PLATE IV G, FIGS. 31, 35.

Shell subcircular in outline. Upper valve convex; apex posterior and mar-
ginal. Surface covered with fine, closely crowded, elevated, radiating lines,
which extend to the apex, and increase by intercalation. Lower valve ilat
and of less diameter than the upper. Apex subcentral, posterior. Foramen
apparently a narrow triangular slit extending to the margin. A short median
septum extends forward from the apex. External surface covered with low,
crowded and rather faint concentric lines. On the interior, the surface bears
a series of distant, deep but narrow radiating furrows, about twenty-live in
number; these do not reach the ajjex, and inci'ease in number toward the
margin. Between them are very fine radiating lines. The animal was para-

180 PALEONTOLOGY OF NEW YORK.

sitic in its habit, attachment being considerably aided by the overlapping
margin of the upper valve. Length and width of an average adult ; upper
valve, 9 mm., lower valve, 7.5 mm.

Lower Helderberg group. Near Clarksville, N. Y.

Crania agaricina, sp. nov.

PLATE IVh, FIG. 2.

Shell small. Apex posterior, slightly elevated. Surface covered by a few
coarse, elevated, radiating lines, of which about twelve reach the apex.
These increase by intercalation toward the margin, to about thirty. The
edges of these ridges appear to be minutely granulose. Length of the orig-
inal specimen (allowing for its incurvature upon the surface of attachment),
5 mm.

Lower Helderberg group. Near Clarksville, N. Y.

Crania pdlchella, sp. nov.

PLATE IV H, FIG. 3.

Shell like that of C. agaricina, but larger and with much finer, more numerous
radiating ribs. These are about sixty in number at the margin of the valve.
Length of the original specimen, 8 mm.

LoAver Helderberg group. Near Clarksville, N. Y.

Crania qranosa, sp. nov.

PLATE IV H, FIGS. 19, 30.

The original specimen is an upper valve, (^uite irregular in its growth, with
a nearly central beak and strong convexity. The surfoce is completely covered
with closely set granules which are somewhat coarser toward the margins A
few concentric wrinkles of growth are also visible. Diameter, 18 mm.

Hamilton group. Centerfield, N. Y.

BRACHIOPODA. 181

Crania favincola, sp. nov.

PLATE IV H, FIG. 3S.

Two interiors of the lower valve attached to a colony of Favosites pirum
have very strongly developed muscular and vascular impressions. The poste-
rior scars are large and their strongly elevated margins unite with the broad
lateral border of the shell. The anterior scars are situated in front of the
center and are partially enveloped by the great elevation of the anterior and
median fulcra. The vascular sinuses are broad, slightly undulating grooves,
extending from the median region to the anterior border. Length, 17 mm.,
width, 21 mm.

Hamilton group. Crab Orchard, Kentucky.

Craniella Ulrichi, sp. nov.

PLATE IV I, FIGS. 1,2.

Shell moderately large. Outline normallj' circular. Apices subcentral, slightly
posterior, inclined backwards. Upper valve with the posterior scars large
and the adjusters well defined ; anterior scars subdivided, the outer or poste-
rior portion possibly representing the insertion of the brachial muscles.
The vascular sinuses make a 3-shaped curve on the lateral portions of the
valve, with the crest of the double arch toward the center; narrowing rapidly,
becoming indistinct over the anterior region. Lower valve regularly convex,
evidently unattached at maturity Anterior adductors very large, situated on
a thickened posterior area Posterior adductor and adjuster scars very faint,
lying just within the margin. The vascular sinuses are a series of low
grooves extending forward in subparallel lines from the' anterior and lateral
margins of the central muscular area. External surface of the valves smooth
or covered with concentric sublamellose growth-lines. Length of an upper
valve, 11 mm., width, 12 mm. ; diameter of a lower valve, 16 mm.

Trenton shale. Minneapolis, Minnesota.

182 PALEONTOLOGY OF NEW YORK.

PUOI.IDOPS CALCEOLA, Sp. IIOV.
PLATE IV r, FIG. 30.

Shell small. Outline subelliptical, the posterior margin being narrowed by
the exter.sioii of the beak, which is long and acute, slightly elevated above
the plane of the margin. External surface marked by concentric lamellose
growth-lines, which extend about the posterior side of the beak. Muscular
area central; posterior margin divided into a lu'oad central and two lateral
arches, from the latter the outline extending in a regular curve to the ante-
rior margin. Adductor scars sharply defined. The dorsal (.') valve only is
known. Length of the original specimen, 3.5 mm.

Corniferous limestone. Falls of the Ohio.

Pholidops patina, sp. nov.

PLATE IV I, FIGS. 27-29.

Shell comparatively large ; outline elongate-ovate or elliptical. Length to
width as 3 to 4. Apex posterior. Surface covered with lamellose con-
centric growth-lines, which are crossed by fine, interrupted radiating striae.
The interior of the ventral (?) valve has the anterior and posterior adductors
well defined, the latter being lobate. The median scars are well developed
and the parietal impression acutely angled at the center. In the opposite
valve the anterior edges of the muscular area are sharply elevated, both pairs
of adductor scars prominent, and the parietal scar extended posteriorly.

Corniferous limestone ; from boulders of decomposed chert. De Cewville,
Ontario.

BRACHIOPODA. 183

SLPPLEJNtEXTARY >;OTE ON THE GENUS KUTORGINA.

Some interesting observations which bear upon the phylogenetic rehitions of
this obscure genus, have recently been made by Mr. G. F. Matthew, in a paper
entitled " Canadian Organisms in Acadia," published in the Transactions of the
Royal Society of Canada, article xii, p. 135. 1890. The author has described
and illustrated the development of his species, Obolus pulcher (see Plate IV k,
fig. 22), and though it may not be proven that this form can be safely included
within the genus Obolus, it is distinctly oboloid. These observations are based
upon adult shells which retain evidence of differential stages of shell-growth
with sufficient distinctness to allow of the following subdivision :

" (1) Embryonic. Formation of the embryonic shell.

'' (2) Larval. Lengthening of the hinge-line and acquisition of mantle

margins.
" (o) Adolescent. Fixation of the hinge-line, otherwise as the last, except

the radular ornament jjecomes irregular.
" (4) Adult. Absence of radular ornamentation on the valve and great

expanse of the mantle margin."

In the earliest stages represented (plate viii, figs. 1 a-e, brachial valve, figs. 2
a-d, pedicle-valve), the hinge is straight and long, making the greatest diameter
of the shell, the umbo of the pedicle-valve is elevated and the cardinal area
erect and with a triangular pedicle-aperture. The resemblance to Kutorgina
in the growth-stage is at once striking, and it mav serve to indicate the sub-
ordinate value of this genus in its relation to the oboloid stock.

BRACHIOPODA. 185

BRACHIOPODA ARTICULATA.

Valves articulated ; intestine terminating in a blind sac ;* shell-substance essentially

calcareous.

So far as our knowledge of the fossil species extends, there are very few of
the forms included in this division to which the above definition does not apply.
Several genera show very considerable modification of the articulating appa-
ratus, but with rare exceptions these modifications in each group appear to be
progressive, extending along certain lines of development and finally acquiring
an extravagant manifestation, which may terminate abruptly or result in the
degeneration and obsolescence of some of the parts.

In the group of fossils which are currently referred to Orthis there are
several well marked subdivisions, which are in some degree coincident with
geological succession, and the later of these show a tendency to the extravagant
development of certain characteristic features, while the genus Enteletes,
which can be affiliated only with Orthis, presents a most remarkable exaggera-
tion in the development of certain parts.

On the other hand, the articulating apparatus in Strophodonta, Productus,
etc., is by some authors regarded as being in a degenerative condition, and on
this account they would place these genera near the base of the articulate
division, though the type of structure exhibited by them is much more highly
modified than in Orthis and its immediate allies in the older rocks.

The mode of articulation in Productus appears to have come legitimately
from the progress and development of some portions of the articulating appa-

*The definition of the bkachiopoda inarticulata and eeachiopoda articdlata i.s derived from the
stmcture of ^analogous living' forms.

186 PALEONTOLOGY OF NEW YORK.

ratus on the one hand, and the obsolescence of other characters, which appear
in the earlier forms of strophomenoid shells and have become modified in their
progress through the chonetids. This may in one aspect be regarded as a
degeneration, while in another it is apparentl}^ a development or progress, and
affords no sufficient reason for beginning at the end of a series and going
backward.

Of the various designations which have been proposed with a signification
equivalent to Professor Huxley's term* for this subdivision of the Brachiopoda,
are Akthrgi'OMATA, Owen,! Clistenterata, King;| while Bronn§ made use of
the two names Testicardines and Apygia.

No attempt is here made toward any grouping of the genera into the
numerous families or sub-families which have been proposed by different
authors. In this division, as in the Brachiopoda Inarticulata, our knowledge
has so greatly increased in the past years that such a classification if attempted
must be arbitrary and procrustean, and would only be embarrassing to the
student without any corresponding benefit. The interrelations of these genera
will be better understood from the discussions under each one, and will be
briefly summarized in a concluding chapter.

Genus ORTHIS, Dalman. 181^8.

PLATES V, Va, Vb, Vr. VI, VIA.

Ilyxterolithii/i (partim), of Aldrovandcs (1648) and othei- pi'fe-Linnean authors.
1820. UysteroVithct (partim), Schlothbim. Die Petrefactenk. auf ihi-. jetzig. Stancijmnkt.
1S28. Orthis. Dalman. Kong-l. Svenska Veten.skapsAkad. Haiidl. for 1827, pp. 93, 96; pis. i, ii.
1830. Orthamlxmites, Poratnbonites (parlini). Pander. Beitr. zur Geogii. des riissisch. Reiches,

pp. SO, 9!5.

Deltliijris, ^pirifer, Pioductiis, Terehro,tula of some early authors.

Orthis of authors {generally.
1838. Or«M, Conrad. Second Annual Kept. N. Y. fieol. Survey, pp. 112, US.
1842. Orthis, Terebratula. iSpirifcr, D'ORiiiGNV. Voyage dans rAnierique nu'ridionale, Paleontologie,

pp. 27, 38, 39, 48.
1842. Orthis, Delthyris, Emmons. Geology of N. Y. ; Rept. Second Dist., pp. 394, 396, 404.
1842. Orthis, Vanuxem. Geology of N. Y. ; Rept. Third Dist.. pp. 139, 140, 163, 164.

■ An Introduction to the Classification of Animals, p. 116. 1869.
t Encyclo])jcdia Britannica. 8th ed., vol. xv, p. 336. 1858.
I Aunals and Magazine of Natural History, vol. xii, p. 1.^. 1873.
§ Die Classen und Oidnnngen des Thierreichs, p. 301. 1862.

BRACHIOPODA. 187

1542. DeWiyrhi (partim), Conrad. Journ. Acad. Nat. Sei.. Philiutelpliia, vol. viii, pp. 2C0. 262.

1843. Spirifer, Castelkav. Essai sur le Syst. Sil. de rAinerique septentrionale, p. 42.

1543. OrHiiSy Strophoinaia. Cosrad. Pi-oc. Acad. Nat. Sci., Philadelphia, vol. i, pp. 183, 332, 333.
1S43. OitJiis, Dillhyrli.Atrypaf Hall. (Jeolopry of N. Y. ; Kept. Fourth Dist.,pp.70, 71,105, 175, 21."),

267, 271.

1844. Ortliis, DeUhyris (partim). Owex. Kept. Geol. Expl. Iowa, Wisconsin and Illinois, plates xii,

xiv, XV, xvii.

1845. Uiilii.':, Hall. Amei-ieaii Joninal of Science, vol. xlviii, p. 2i)4.

1846. Chillis, McCoy. Synopsis Siliii-ian Fossils Ireland, p. 32.

1847. Orthis, ndtl>y,-is, Leptmm, Hall. PaUrontology of N. Y., vol. i, pp. 20, 1 13, 117, 13i;, 288. 289.
1847. Orthis, Yandell asd Shumard. Contribution Geology Kentucky, p. 21.

1852. Orthis. Owen. Rept. Geol. Surv. Wisconsin, Iowa and Minnesota, p. r)8.5.

18.52. Orthis, Spirifer, Hall. Palieonlolofry of N. Y., vol. ii, pi>. 56-.58, 65, 2.52-25.5, 260.

[?] 1855. Orthi.i, Shomard. Rejit. Geol. Surv. Missouri, p. 205.

1856. Orlhia, BlLLtNciS. Canadian Naturalist and Geolog'ist. vol. i, pp. 40, 134, 136, 205, 206.

1857. Orthis, Hall. Tenth Ann. Rept N. Y. State Cab. Nat. Hist., pji. 41-46. 102. 110, 135.

1857. Orthis, Billings. Rept. Prog. Geol. Surv. Canada, p. 296.
18.57. Orthis, Cox. Owen's Geol. Surv. Kentucky, vol. iii, p. 570.

1858. Orthis, Marcoc. Geology of Noith America, p. 48.

1858. Orthis, Hall. Transactions Albany Institute, vol. iv, p. 12.

1858. Orthis, Hall. Geology of Iowa, vol. i, pt. ii, pp. 486, 596.

1858. Orthis. DeUhyris. Roqers. Geology of Penn., vol. ii, part 2, pp. 818, 820.

1858. OrtMs, Swallow. Trans. St. Louis Acad. Science, vol, i, p. 218.

1859. Orthis. Billings. Hind's Expl. Assiniboine, Saskatchawan. etc.. p. I'.i3.

1859. Orthis, Billings. Canadian Naturalist and Geologist, vol. iv, pji. 434-440. 442.

1859. Orthis. Salter. Cjin.adian Organic Reni.ains. Decade i, p. 39.

1859. Orthis, Hall. Pala-ontology of N. Y.. vol. iii, pp. 162-172. 174-176, 179, 409, 481.

1859. Orthi.'i, Strophomemi, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., pi). 66. 7t), 72, 85.

1860. Orthis. Hall. Thirteenth Ann. Re)it. N. Y. State Cab. Nat. Hist., pp. 78-80, 111, 120, 121.
1860. Orthis. SiiiMARD. Triins. St. Louis Acad. Science, vol. i, p. 627.

1860. Orthis, F. Roomer. Die silur. Fauna westlich. Tennessee, pp. 62, 63.

1860. Orthis, Billings. Canadian Journal Science and Arts, vol. v. pp. 267, 269.

1860. Orthis, Swallow. Trans. St. Louis Acad. Science, vol. i, p. 639.

1860. Orthis. White. Journal Boston Society Natural History, vol. vii, p. 231.

1861. Orthis, Hall. Fourteenth Ann. Rejit. N. Y. State Cab. Nat. Hist., pp. 89, 90.
1861. Orthis, McChe.sney. Descriptions New Palaeozoic Fossils, pp. 29, 77.

1861. Orthis, Hall. Ann. Rejrt. Geology Wiscon.'sin, pp. 42, 54, 435.

1862. Ortfiis, Trematosinra f Hall. Fifteenth Ann. Rept. N. Y. State Cab. Nat. Hist., plate ii.
1862. Orthis, White and Whitfield. Pi-oc. Boston Society Nahiral History, vol. viii. p. 292.
1862. Orthis, A. Winchell. Proc. Acad. Nat Sci. Phila., vol. xiv, pp. 400, 409.

1862. 0>-t7iL^, Strophomena, Billings. Pala-ozoic Fossils, vol. i, pp. 76 79, 81-83, 130, 133. 135-137.

1863. OrthU, Hall. Sixteenth Ann. Rept. N. Y. State Cab. Nat. Hist., pp. 32, 33.
1863. 0)i.his, Swallow. Trans. St. Louis Acad. Science, vol. ii, p. 81.

1863. Orthis, Hall. 'IVan.-=actions Albany Institute, vol. iv, p. 209.

1863. Orthis, Billings. Geology of Canada ; Report of Progress, pp. 129. 130. 165. 167-169, 210, 231,

312, 369, 384.

1864. Orthis, Meek. Palseontology of California, vol. i, p. 10.

1864. Orthis, A. Winchell. American Joui'nal of Science, vol. xxxvii, p. 228.

1865. Orthis, Billings. Paleozoic Fossil.s, vol. i, pp. 185, 217, 301, 303.
1865. Orthis, A. Winchell. Proc. Acad. Nat. Sci. Phila., p. 116.

1865. Orth'is, PlatystropMa, Shaler. Bull. No. 4, Mus. Comparative Zoology, pp. 65, 67.

1866. Ortliis, Billings. Cat. Silurian Fossils Island Anticosti, pp. 12, 41.

188 PALEONTOLOGY OF NEW YORK.

1867. OrtMs, Hall. Pal.-KOntology of N. Y., vol. iv, pp. 33-63.

1868. Ortkis, Haktt. Daw.son's Acadian Geolog}-, 2d ed., pp. 599, 644.

1868. Ortliis, Mkbk and Wokthen. Geological Survey Illinois, vol. iii, pp. 371, 373, 423, 424.

1868. Orthis, Meek. Trans. Chicago Acad. Sciences, vol. i, pp. 88-90.

1868. OrtMs, McChe.snby. Trans. Chicago Acad. Sciences, vol. i, p. 29.

1869. 0)-tMs, Safford. R<>pt. Geology Tennessee, pp. 286, 328, 533.

1870. Orthis. A. Winciiell. Proc. Amer. Philosophical Society, vol. xii, p. 251.
1870. Orthis, Meek. Proc. Amer. Philosophical Society, vol. xii, p. 425.

1872. Orthis, Meek. Final Rept. Palseont. Eastern Nebra-ska, p. 173.

1872. Orthif, Meek. Prelim. Rept. U. S. Geological Snrvey Montana, p. 295.

1872. Orthif!, Meek. American Journal of Science, vol. iv, p. 281.

1872. OrHris, Hall a.nd Whitfield. Twenty-fourth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 181.

1873. Orthis (Platystrophia), Meek. Geological Survey of Ohio; Palfeontology, vol. i, pp. 92, 114.
1873. Orthis. Meek. Sixth Ann. Rei)t. U. S. Geological Survey Territories, p. 464.

1873. Orthi.'i. Meek and Worthen. Geological Survey Illinois, vol. v, p. 571.

1874. Orthis, Dekby. Bull. Cornell Univei'sity, vol. i, No. 2, pp. 26, 29, 63.
1874. Orthis, BiLi.iNn.s. Palretjzoic Fossils, vol. ii, pp. 32-35.

1874. Orthis (Platystrophia), .Iambs. Cincinnati Quarterly Journal of Science, vol. i, p. 19.

1874. Orthis, R.athbu.\. Bull. Buffalo Soc. Nat. Hist., vol. i, p. 247.

1874. Orthis, Nicholson and Hinde. Canadian Journal, new series, vol. xiv, pp. 144, 158.

1875. Orthis, Miller. Cincinnati Quarterly Journal of Science, vol. ii, pp. 19-40.
1875. Orthis, White. Wheeler's Survey 100th Meridian, pp. 55, 70, 74, 125.
1875. Orthis, Nicholson. Rept. Palajontology. Pi'ovince Ontario, pp. 16, 47.

1875. Orthis, Hall and Whitfield. Geological Survey Ohio: Pateonfology, vol. ii, i>p. 75-77.

1877. Orthis. Mkek. U. S. Geological Expl. Fortieth Parallel, vol. iv, ji. 6.{.

1877. Orthis, Hall and Whitfield. U. S Geological Expl. Fortieth Pai-allel, vol. iv, pp. 332. 265.

187S. Orthis, ('alvin. Bull. U. S. Geological Sui'v. Territories, vol. iv. No. 3, p. 72S.

1879. Orthis, Rathbun. Proc. Boston Society Natural History, p. 23.

1879. Orthis, James. Palieontologist, No. 4, pp. 26, 31.

1879. Orthif, Ulrich. Journ. Cincinnati Society Natural History, vol. ii, \>. 15.

1879. Orthi.% Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 149.

1880. Orthis, N. H. Winciiell. Eighth Ann. Rept. Geol. and Natural History Survey of Minnesota,

pp. 63-68.

1880. Orthis, White. Second Ann. Rept. Bureau Stat, and Geology Indiana, pp. 484-486.

1881. Orthis, White. Tenth Repoit Indiana State Geologist, pp. 116, 133.
1881. Orthis, White. Wheeler's Survey 100th Meridian. Appendix, p. xxiii.
1881. Ortliis, N. H. Winchbll. Ninth Ann. Rept. Gcol. Sui-v. Minnesota, p. 115.

1881. Orthis, Miller. Journ. Cincinnati Society Natural History, vol. iv, pp. 8, 313.

1882. Orthis, Miller. Journ. Cincinnati Society of Natural History, vol. v, pp. 16, 40.

1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, pt. 3, Pala-ontology, pp. 258, 260, 320, 326.

1882. Orthis. Hall. Eleventh Ann. Rept. State Geologist Indiana, pp. 268, 285, 286.

1882. Orthis, Whitfield. Bull. American Museum Natural History, vol. i. No. 3, p. 45.

1883. Orthi.% Hall. Thirty-sixth Ami. Rept. N. Y. State Mus. Nat. Hist., pp. 73-75.
1883. 0W7U.S-, Hall. Twelfth Aim. Rept. St.ate Geologist Indiana, p. 324.

1883. Orthis, White. Twelfth Ann. Rept. U. S. Geol. Survey Territories, p. 164.

1883. Orthis, Hall. Ann. Rept. N. Y. State Geologist for 1882, plates 34-37.

1883. Ortliis, Hall. Transactions Albany Institute, vol. x, p. 70.

1884. Orthis, White. Thirteenth Ann. Rept. State Geologist Indiana, p. 129.

1884. Ortlds, Walcott. Palieontology of the Eureka District, pp. 22, 72, 74, 114, 115.

1885. Ortln.i, N. H. Winchell. Fourteenth Ann. Rept. Geol. and Nat. Hist. Surv. Minnesota,

pp. 317, 318.

1885. Ortliis, Fokkstb. Bull. Deni.son University, vol. i, pp. [80-87.

BRACHIOPODA. 189

1886. OrtM.% WAI.COTT. Bull. No. 30, U. S. Geolosiial Survey, ji. 119.

1886. Oithis, Whitkiki.d. Bull. Amciican Museum Natural History, vol. i, No. 8. p. 300.

1887 Oi-tliis, Pluti/stropliia, Sh.vlkh. Mom. Kentucky Geoloj,'-ic-nl Survey, vol. i, jil. li, \>]>. 18, 19, 2'J.

1887. Ort/ils. WALcorr. Amerioan Journal of Si ience, vol. xxxiv, p. 190.

1888. Orthis, Herrick. Bull. Denison University, vol. iii, p. 38; vol. iv, j). 14.

1888. OithiK, RiNfiniiBKRG. Pioc. Acad. Nat. Sci. Phila., p. 134.

1889. Orthis, Whitfield. Bull. American Museum Natural History, vol. ii. No. 'J, \\. 43.
1889. Orthis, NiiTTEi.RoTH. Kentucky Fossil Shells, pp. 32-45.

1889. Orthis, Beecher and Clarke. Mem. N. Y. State Museum, vol. i, No. 1, pp. 14-17.

1889. Orthi.t, Simpson. Trans, .\merican Philosophical Society, p. 437.

1890. Orthis, Foerstb. Proc. Boston Soc. Nat. Hist., vol. xxiv, p. 308.

D1.A.GNOSIS. Shell subcircular or subquadratc in outline. Valves more or less
convex, the smaller or brachial valve being sometimes nearly flat or slightly
concave. Hinge-line straight and equal to, or shorter than the greatest width
of the shell. Cardinal area well developed on each valve and divided
by an open triangular delthyrium.* Beaks more or less incurved. Surface
covered by radiating costae, with faint evidence of median fold and sinus.

In the interior of the pedicle-valve the large hinge-teeth are supported by
dental plates which are more or less conspicuously developed, frequently
resting upon the bottom of the valve The bases of these are continued as
a low elevation about the muscular area. The subdivisions of this muscular
impression are rarely distinct; it is divided longitudinally by an inconspicuous
median ridge and the larger expansions on each side were probably occupied
by the diductor muscles ; within these and lying close against the median
ridge are the adductors, while the pedicle muscles covered the posterior
deltidial portion of this area.

In the interior of the brachial valve the apex of the deltidial cavity bears

*The term deltiditmi was proiiosed by von BncH for the triangular jjto^i which, in many articulate
genera, covers more or less completely the space between the outer margins of the dental ridges. This
plate he describes as composeil of two pieces which may eithei- completely sui-roimd the foramen (dMidium
amplectens), bound it on its lower side [deUidiwui sectans), ov the parts may be separated for their entire
length by the foi-amen {deltidiiim dism-elmii). These component parts of the delli<lium take their origin
from the margins of the triangular cavity beneath the beak, but in some genera, particulai-ly in Stropho-
mena, Spiriker and their allies, there is .still another form of shelly plate which grows from the apex down-
waid, and to this the term pseudodMidium was ajiplied by Bro.n.v. Among recent wiiters thei-e has been
considerable laxity in the use of the.se teinis and it is very doubtful if they can be applied with precision.
In the discussion of miiture characters with which this work has principiilly to deal, the term
dettidium is applied to the outer plate <-overing the deltoid fissure, irrespective of valves, and for this so-
called " deltidial fissure," the term deHhyrium (SiXra and dvpiov) is suggested.

190 PALEONTOLOGY OF NEW YORK.

a more or less developed cardinal process or callosity, which, in the typical
group, is elongate and usually simple at its termination. The dental sockets
are deep and their inner walls support short divergent crura. The muscular
impression is more or less distinctly quadruple, being divided longitudinally
by a median ridge extending forward from the cardinal process, and trans-
versely by fainter ridges. This quadruple scar marks the place of attachment
of the adductor muscle.

Ramified vascular markings are often retained over the pallial area, the prin-
cipal trunks diverging from the median region and nearly following the curve
of the anterior margin of the shell. Between these and the adductor impres-
sions the markings of the ovarian areas are sometimes visible.

Shell-structure fibrous and impunctate in the typical group.

Observations. The foregoing diagnosis is based upon a stricter inter-
pretation of the generic characters than usually adopted by authors. The
very great number of species which are currently referred to the genus, and
the constant reference of new species of varied character to the same generic
term imply a want of liomogeneity in the group, while in the present state of
knowledge it seems possible to indicate certain differential characters which
will serve as a basis for subsidiary classification. Differences in external con-
tour of the species are often extreme. The mind unwillingly associates the
transversely elongated, Spirifer-like forms of Orthis bifurata with the round,
lenticular shells of Orthis testudinaria, the cordate Orthis biloba, or the inflated
and resupinate Orthis Macfarlanii. In the muscular markings also there are
some extreme variations; e. g., Orthis calligramma, with the scars obscure and
confined to the umbonal region, Orthis ?nvsculosa, having them very deep and
of immense size, covering almost the whole of the inner surface of the pedicle-
valve. The cardinal process varies in its form, size and degree of lobation ; the
dental lamelljB are more or less prominently developed, and of still greater
importance is the fact that in its minute anatomy the shell is sometimes
compactly prismatic and impunctate, sometimes of looser texture and the inner
laminaB abundantly supplied with vertical tubules.

■BRACHIOPODA. 191

The genus Orthis was thus defined Ijy Dalman :*

" Testa intec^uivalvis, aequilatora ; valva niinori subplana, niajori convexa.
" Margo cardiiialis rectilineus, latus, foraiuine deltoideo sub nate valvas
majoris."

Nine species were cited as examples of the genus, and in the following order:
O. ? peden, 0. striatella, 0. zottaia, 0. calladis, 0. calligramma, 0. testudinaria,
0. basalts, 0. eleganlula, 0. demissa.

lyir. Davidson quite properly takes exception! to the use of the first of these
as the type of the genus since the author himself J expressed a doubt of its
validity by the use of the interrogation point, and the shell proves to be a
strophomenoid (Strophonella).§ The second species, O. striatella, was taken by
Fischer de Waldheim, in 1837|| as the type of his genus Cjionetes, and with
entire propriety, as its generic chai'acter was also placed in doubt by Dalman
in his description of the species.

Orthis zonata, the third species, was referred bj' de VerneuilH to Orthisina ad-
scendens. Pander, but the figure of this species given by Dalman indicates that
it had an open delthyrium, though it is (juite possible that the deltidiuni had
been destroyed in the original specimen, as frequently occurs in such fossils.
Little is known of this species, but under the now accepted rules of priority
it should be taken as the typical form of the genus. This procedure, however,
would be impracticable at the present time, and would create a deplorable
disturbance in nomenclature without giving any beneficial result. The
fourth species in the list, 0. calladis, and the fifth, 0. calligramma, are well
known and very closely allied to each other. They are characteristic members
of Silurian faunas, ranging from the Llandeilo to the Wenlock formations,**
and represented in America by 0. tricenaria and 0. disparilis, Conrad, of tlie

* Uppstalliiing- och Beskrifning af <le i Svei-ige fanne Tei-ebraialiter, loc. cit. pp. OH. 97 ; pi i, figs. .I a,
b, 6 a-d ; pi. ii, tigs- 1 a-e, 2, 3 a-d, 4 a-e, 5 a-e, 6 a-g, 7 a-d.

+ Introduction to British Fossil Brachiojioda. i>. 103, 1853. and General Summary, ji. 377. 1884.

I Dalman, op cit. p. 110.

§ See David.so.x, British Silurian Bracliiopoda, p. 304. 1871.

II Oryct. Gouvern. de Moscon, part ii, p. 134.

^1 Geologie de la Russie d'Eiirnpe et des Montagnes de I'Oural; p. 203. 184.5.
** British Silui-ian Brachiopoda, p. 24.').

192 PALEONTOLOGY OF NEW YORK.

Trenton, and 0. Davidsoni, de Verneuil (0. calli gramma, var., according to
Davidson*), of the Niagara.

Mr. Davidson was disposed to regard the Swedish specimens of 0. callactis as
showing but varietal differences from 0. caUigramma, and his use of these two
terms, the former subordinate to the latter, .should strictly be reversed. Orthis
callactis may, therefore, properly be taken as the typical form of the genus in
its restricted construction, and upon the diagnosis above given it will be neces-
sary to exclude the remainder of Dalman's species, with the exception of 0.
demissa, as it will be shown that 0. testudinaria, O. basalts and 0. elegantula be-
long to a distinct type of structure.!

ORTHIS, Dalman, as restricted.
I. Group of Orthis callactis, Dalman. 1828.

TLATE V, FIGS. 1-17, 37-41.

1828. OrtUs, Dalman. Kongl. Vet. Acad. Hiindl., pp. 93, 90.

1830. Orthamboii.lt.es. Pander. iSeitr. zur geogncis. des i-ussisch. Reiches, p. 80, pi. iii, fig. 7 ; pi. xxviii,

fig. 18.

1839. Orthis, SowKRBY. Murchison's Silurian Syst., p. 639, pi. xxi, tig-. 8.

1843. Orthis, Hall. Geology N. Y. ; Rept. Second Dist., p. 105, fig. 3.

1843. Orthis, Conrad. Pi'oc. Acad. Nat. Sci., Philadelphia, vol. i, p. 333.

1844. Orthis, Owen. Geol. Expl, Iowa, Wisconsin and Illinois, pi. xv, fig. 11.

1847. Orthis, Hall. Pala;ontology N. Y., vol. I, p. 20, pi. iv his, fig. 4 ; pp. 119, 121, pi. 32.

18r)2. Orlhin. Hall. Palseontology of N. Y., vol. ii, pp. 254, 255, pi. Iii, figs. 6, 7.

1856. Orthis, Billings. Canadian Nat. and Geol., vol. i. p. 136, pi. ii, fig. 6.

1859. Orthis, Billings. Canadian Nat. and Geol., vol. iv, p. 440, fig. 20.

1859. Orthis, Salter. Canadian Organic Remains, Decade i, p. 39, pi. ix, figs. 1-4.

1862. Orthis, Billings. PaU-eozoic Fossils, vol. 1, p. 77, fig. 70; p. 78, fig. 71; p. 81, fig. 73.

1862. Orthis, Hall. Geology of Wisconsin, vol. i, p. 42, figs. 8-11 ; p. 435.

1863. Orthis, Billings. Geology of Canada, p. 130, fig. 60; p. 11)7. fig. 151 ; p. 231. fig. 245; p. 312,

fig. 318.
1865. OrtMs, Siialer. Bnllclin No. 4, Mns. Comparative Zool., p. 66.
1875. OrthU, Nichol.son. Palaeontology Province Ontai-io, p. 47, fig. 21.
1875. OrttiU, White. Geogr. and Geol. Expl. west 100th Merid., p. 72, pi. iv., tig. 10.
1883. Orthis, Hall Rept. N. Y. State Geologist for 1882, pi. xxxiv, figs. 35-38, 41, 42 and pi. xxxv,
figs. 1-8.

* Bi-iti.sh Silurian Brachiopoda, p. 244.

t Dalman'.s paper of 1828 has become so rare as to be beyond the reach of most American students.
We have, therefore, rei)rodii<:ed by jihoto-engraving the fii-st two plates of this work with the precise form
and arrangement of the original, and they will be found inserted at the end of these discussions, and pre-
ceiling the lithographic plates. These plates are Tab. I and II of the Kong. Vetenskaps-Academiens
Handlingar for ar 1827, and bear all of the authoi-'s figures of the species of Oktiiis as well a.s those of his

genus LEPTiBNA.

BRACmOPODA. 193

18S4. Orthis, Walcott. Palaeontology Eui-eka Dist., p. 74, pi. xi, tig. 4.

1885. OH/iii, FoBBSTE. Bull. Denison Univ., vol. i, p. 82, pi. xiii, &g. 12.

1889. Oitliis, Nettblroth. Kentucky Fossil Shells, p. 38, pi. xxxiv, fig-. 30.

1890. Orthis, Foerste. Pioo. Boston Soc. N;it. Hist., vol. xxiv, p. 308, pi. vi, figs. 4, 5.

The distinguishing features of these shells are the plano-convex contour ; the
strong, sharp and comparatively few costoo, rarely, if ever, bifurcating ; the
elevated and somewhat incurved cardinal area on the pedicle-valve ; the relatively
slight development of the dental hunellae, which do not extend the entire length
of the umbonal cavity. The cardinal process on the brachial valve is an elongate,
vertical plate, extending from the apex the whole length of the delthyrium, thus
longitudinally dividing the deep deltidial cavity. It is usually simple, both on
the outer edge and at its distal extremity.

In this group of orthids, more frequently than elsewhere, we find a charac-
ter i-arely developed in any stage of growth, viz. : the existence of a transverse
apical plate in the delthyrium of the pedicle-valve. This is probably homologous
to the apical plate of the Spirifers, but is wholly distinct in origin from the
covering of the delthja-ium. The greatest development attained by this feat-
ure, in any of the numerous species of Orthis studied, is to be found in 0.
tricenaria of the Trenton and Hudson faunas ; it has also been observed in 0.
calligramma, var. Davidsoni, although it does not appear in any of the figures of
this species and its varieties given by Mr. Davidson, nor is any mention made
of it in his descriptions.* Its appearance in this genus, and especially in the
typical species of the genus, is interesting, but it can not be embraced in the
diagnostic characters since its presence appears to be largely of a specific
value, and the degree of its development dependent upon the stage of growth.

The muscular scar of the pedicle-valve of 0. calligramma is a subelliptical
area scarcely longer than the cardinal face, faintly impressed, and its compo-
nents rarely distinguishable.

The structure of the shell is compactly fibrous and impunctate. Specimens of
Orthis calligramma, var. Davidsoni, from Gotland, show openings of oblique tubules
on the external surface, always situated upon the keels of the costae. These
are sparse and irregularly scattered, but of similar nature to those seen in the

* See British Silurian Brachiopoda, p. 240, pi. xxxv, figs. 1-19.

194 PALEONTOLOGY OF NEW YORK.

impunctate species, 0. subquadrata, and the punctate species, O. subequata, 0.
Michelini, 0. resupinata, and their allies.

The Orihis? laurentina, Billings, from the Anticosti group, is an interesting
species, similar in surfoce, contour and interior to Orthis calligranima, but in the
pedicle-valve the delthyrium is persistently covered with a convex plate without
trace of an opening, and in the brachial valve the deltidium is more or less
complete.

PLECTORTHIS

(iiom. propos).

II. Group of Orthis plicatella, Hall.

PLATE V, FIGS.18-26.

1847. Ortkls, Hall. Palaontoldgy N. Y., vol. i, pp. 120-122, pi. x.Kxii, figs. 6. 7, 9.

1861. Orthis, McChe.sney. Desciiiifion New P.ilEeozoic Fossils.tp. 77.

1861, Orthis. Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 121.

1861. Oi-tliis, Hall. Fourteenth Rept. N. Y. State Cab. Nat. Hist., p. 90.

1862. Orthis, cf. Trematosinra, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pi. ii, figs. 6-8.

1863. Orthis, Billings. Geology of Canada, p. 165, fig. 145.

1868. Orihis, McChesney. Transactions Chicago Acad. Sci., vol. i, ji. 29, pi. ix, fig. 3.

1872. Orthis, Meek. American Journal Science, vol. iv, p. 281.

1872. Orthh, JIeek. Paleontology of Ohio, vol. i, pp. 106-109, pi. viii, figs. 6-8.

1 1873. Orthis, Meek. Palaeontology of Ohio, vol. i, p. 105, pi. viii, fig. 9.

1 1874. Orthis, Billings. Palaeozoic Fossils, vol. ii, p. 34, jil. 3, tig. 3

1875. Orthis, Hall and Whitfield. Paljeontology of Ohio, vol. ii (? p. 76, pi. i, fig. 20); p. 77, pi. i,

figs. 21, 22.

1875. Orthis, Miller. Cincinnati Quart. Jour. Sci., vol. ii, pp. 30-33.

1879. Orthis, Ulbich. Journal Cincinnati Soc. Nat. Hist., vol. ii, p. 15, pi. vii, fig. 11.

1881. Orthis, N. H. Winchell. Ninth Ann. Rept. Geol. and Nat. Hist. Surv. Minnesota, p. 11.5.

1884. Orthis, Waloott. Palaeontology Eureka Dist., p. 73, pi. xi, fig. 5.

This is a persistent form, which in American faunas, so far as known, is lim-
ited to the Trenton and Hudson River formations. While it retains the strong
external ribs of tlie typical Orthis, these are not invariably simple {0. fissi casta,
Hall; O.triplicaklla, Meek; 0. (Bquivalvis, Hall, not Davidson; 0. Jamesi, Hall);
the cardinal area of the pi^dicle-valve is comparatively low and the valves are
subequally convex. In the interior the character of the muscular scars, dental
lamellae and cardinal process is essentially the same as in Group I, and the
minute structure of the shell appears to be in precise agreement with that of
0. calligramma, though no evidence of tubulose costse has been observed. In

BRACHIOPODA. 195

Orthis Jamesi, wliich is placed in this association, there is occasionally a devia-
tion toward the resupinate contour exemplified in the Groups IV and V,

DINORTHIS

(num. iiropos).

III. Group of Orthis pectinella (Conrad, MS.), Emmons.

Pl.ATK V, FIGS. 27-36.

1842. Orthis, EmmOxNS. Geology N. Y. ; Rept. Second Dist., p. 394, (ig. 2.

1847. OHUs, Hall. Pala;ontolog-y of N. Y. ; vol. i, pji. 123, 124, pi. xxxii, tigs. 10, 11.

1856. Orthis, Billings. Canadian Nat. and Geol., vol. i, p. 136, pi. ii, tig. 6, and p. 205, fig-. 5.

IS.'iS. Orthis, Rogers. Geology of Pennsylvania, vol. ii, p. 818, fig. 602.

1863. Orthis, Billings. Geology of Canada, p. 165, fig. 147.

1881. Orthis, N. H. Winchbll. Ninth Annual Rept. Geol. and N.at. Hist. Surv. Minnesota, p. 117.

1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, p. 259, pi. xii, fig. 8.

1883. Orthis, Hall. Rept. N. Y. St.ate Geol. for 1882, pi. xxxiv, figs. 3S), 40.

This group of shells, in its most characteristic examples, presents a reversal
of the relative convexity of the valves as seen in Orthis calli gramma. The ped-
icle-valve, elevated at the umbo, becomes gradually depressed ha growth ad-
vances, and in the mature condition is liat or gently concave over the pallial
region. The brachial valve, on the other hand, is eminently convex. The
surface is marked by strong, simple, rarely bifurcating costa), as in O. calli-
gramma. The cardinal area of the pedicle-valve is well developed but not
greatly elevated. In the interior the dental lamellae are prominently devel-
oped and are extended around a subquadrate muscular area, the strength of
which apparently depends upon the age and thickness of the shell. The three
pairs of impressions may often be distinguished ; the elongate adductors
occupying a central position and separated by a faint median ridge, the diductors
forming large ante-lateral expansions enclosing the adductors ; the adjustors
lie outside and behind these. Occasionally, in Orthis pectinella, there is again
seen the gradual closing of the delthyrium of the pedicle- valve by an apical
callosity, but it is never carried as far as in the forms mentioned in the group
of Orthis calladis, and, so far as observed, its existence is confined to the
species cited. In the brachial or more convex valve the area is narrower, the
crural plates stronger than in the preceding groups, and the cardinal process,
instead of being a simple linear ridge lying in the bottom of the deltidial cavity,

196 PALEONTOLOGY OF NEW YORK.

is an erect apophysis, bi'oadened and frequently bilobed on its summit and
posterior face.

The shell-structure, like that of Orthis callactis and 0. plicatella, is compactly
fibrous, and in all the species examined, impunctate. No evidence of tubulose
plications has been seen.

In American faunas this is a small section limited to a few Silurian species,
such as 0. pec.tinella, Conrad, and 0. Sweeneyi, N. H. Winchell, from the Trenton
limestone, and it is closely allied in some general respects to the typical mem-
bers of Group V, but the minor differences will be found of permanent value.

The other impunctate reversed shells may be separated into two groups,
first, —

PL^SIOMYS

(nom. propos).

IV. Group of Orthis subquadrata. Hall.

PLATE Va, figs. 14-21, 28-34.

1843. Slropkomena, Conrad. Proc. Acad. Nat. Sci.. Pbila., vol. i, p. 332.

1847. OHhis, Leptmna, Hall. Palseontology of N. Y., vol. i, pp. 113. 126, jil. xxxiia, fig. 1 : pi. xxxi b,

tigs. 5, 6.

1858. Orthis, Salter. Mem. Geol. Surv. Great Britain, vol. ii, p. 373, pi. xxvii, figs. 3, 4.

1859. Orthis, Billings. Canadian Nat. and Geol., vol. iv, p. 438, fig. 15.
1859. Stro'phomena, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., p. 70.
1861. Orthis, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 120.

1861. Orthis, McChbsney. Descriptions New Palseozoic Fossils, p. 78.

1862. Orthis, Hall. Geology of Wisconsin, p. 54, fig. 1, 2.

1862. OHhis, StrophomtJia, Billinos. Palsozoic Fossils, vol. i, p. 130, fig. 108 ; p. 133, fig. 110; p. 135,

fig. Ill, and p. 136, figs. 112, 113.

1863. Orthis, Billings. Geology of Canada, p. 129, fig. 54 ; p. 165, fig. 146, and p. 312, fig. 319.
1873. Orthis, Meek. Pala;ontology of Ohio, vol. i, pp. 92, 94, pi. ix, fig. 2, and pi. xi, fig. 7.
1875. Orthis, Miller. Cincinnati Quart. Jour. Sci., vol. ii, pp. 37, 38.

1880. Orthis, White. Second Ann. Rept. Indiana Bureau Statistics and Geol., p. 484, pi. i, figs. 3-5.

1881. Orthis, White. Tenth Rept. Indiana State Geol., p. 116, pi. i, figs. 3-5.
1883. Orthis, Hall. Rept. N. Y. State Geol. foi- 1882, pi. xxxiv, figs. 28, 29.
1887. Orthis, Shalbr. Mem. Kentucky Geol. Surv., pp. 19, 22, pis. vi, vii.

It may be difficult to point out external characters in which the shells of
this section differ from those of Group V. In Orthis subquadrata there is the
same general expression in contour and surface, but the reversal in the con-
vexity of the valves, and the retrorsion of the umbo of the pedicle-valve is

BRACHIPODA. 197

not so great as in species of that section. Tliese features, however, are
regarded as of less importance, but on the basis of internal structure may be
included such forms as Orthis porcata, McCoy, in which the brachial valve is very
convex, and Orthis retrorsa, Salter, where the retrorsion of the beak is carried
to a greater extreme than in any other species of Orthis.

In the interior of the pedicle-valve there is a large quadrate muscular scar
with a tendency to bilobation by the lateral extension of the diductor impres-
sions. The subdivision of this area into separate scars is frequently very dis-
tinct. In the brachial valve the cardinal process is thickened and erect at its
posterior extremity, being distinctly crenulate on the summit and posterior
face. The surface striae are tubulose and the shell-structure fibrous-im-
punctate.

While the muscular scars in this group are somewhat similar to those of
Group III, and the external features like those of Group V, the combination
here described is persistent, though represented by few species. To those
above mentioned may be added O. reversa, Salter, from the Lower Llandovery,
and probably several others from the Silurian of Great Britain.

The type appears to be limited to the faunas of the Lower Silurian.

There is a small group of early species, agreeing with Orthis subquadrata in
the reversion of the valves and the form of the muscular scars and cardinal
process, but characterized by the existence of a more or less completely devel-
oped convex deltidium. To this group belong the Sirophomena dejieda and S.
recta of Conrad, and also a new form here described as Orthis loricula, all from
the horizon of the Trenton limestone. These shells have an elongate hinge-
line, and their external expression is much like that of Strophomena, a resem-
blance which is increased by the presence of the convex deltidium suggesting
a divergence at this point from Orthis toward Strophomena.

198 PALEONTOLOGY OF NEW YORK.

HEBERTELL A

(nom. propos).

V. Group of Orthis sinuata, Hall.

PLATE VA, FIGS. 1-13.

1843. Oi-this, Conrad. Pi-ok. Acad. Nat. Sci. Phila , vol. i, p. 383.

1847. Orthix, Hall. Paleontology of N. Y., vol. i, pp- US, 125-128, pi. xxxii, Hg.-;. 3, 12 ; pi. xxxiia, tig.

2 and pi. xxxiib, tigs. 1, 2.

18.W. OiHiin. Billings. Canadian Nat. and Geol., vol. iv, pp. 43"), 436, figs. 11-14.

1862. (htkis, Billings. Pal;i>,ozoic Fossils, vol. i, p. 137, tig. 114.

1863. Oiihix, Billings. Geology of Can.ad.a, p. 129, figs. f>5, .'56 ; p. 167. figs. 14S. 1.50 and p. 210, fig. 210.
1873. Orthis, Meek. Palsoiitology Ohio, vol. i, pp. 96, 99, 101, pi. viii, tig. 4, and pi. ix, tigs. 1-3.
187;". OHhu, Miller. Cinoiniiati Quart. Jour. Sci., vol. ii, pp. 28, 34, 36, 40.

1875. Orthis, White. Geogi-. and Geol. Expl. west 100th Mei-id. p. 70, pi. iv, fig. 11.

1881. Orthis, White. Tenth Ann. Rept. Indiana State Geol., p. 117, pi. ii, figs. 10-12.

1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, p. 260, pi. xii, figs. 17, 18.

1882. Orthis, Miller. Journ. Cincinnati Soc. Nat. Hist., vol. v, p. 40, pi. i, fig. S.

1883. Orthis, Hall. Rept. N. Y. State Geologi.st for 1882. pi. xxxiv, figs. 31-34 ; pi. xxxv, figs. 16-22.

1884. Orfh'ts, Walcott. Pala;ontology Eui'eka District, pi. 74, pi. xi, fig. 6.

188r>. Orthis, Foerste. Bull. Denison Univei-sitv, vol. i, pp. 85, 87, pi. xiii, figs. 13, 15, 16, 20, 21.

1887. Orlhis, Shaler. Memoirs Kentucky Geol. Survey, plate viii.

1889. Orthis. Nettleroth. Kentucky Fo.ssil Shells, p. 36, jd. xxxiv, tigs. 14-20.

This division is distinguished both by its external and internal characters ;
the pedicle-valve has a well developed, often much elevated cardinal area and
a long, straight hinge-line ; its surface is depressed-convex, always less convex
than the opposite valve which is frequently gibbous or inflated. The surface
is covered with a great number of fine, rounded, closely crowded plications
which increase rapidly by intercalation, and are crossed by lamellose growth-
lines, and fine concentric striae. On the interior of the pedicle-valve the teeth
are large and supported by thick lamellag which are continued as a strong ridge
around a short, obcordate muscular area. This area is medially divided by a
prominent ridge upon the summit of which lies the linear scar of the adduc-
tors. The flabellate lateral impressions are sometimes divisible into their two
components, diductors and adjustors, and in old individuals the impression of
the pedicle-muscle is often distinct.

In the brachial valve the dental sockets are narrow and are enclosed
beneath and on the inner side by the strong crural plates. The cardinal
process is elongate and simple, sometimes thickened, often crenulate, but not
lobed at its posterior extremity. This process unites with the inner bases of

BRACHIOPODA. 199

the crural plates and is produced forward as a median ridge dividing the four
muscular scars, which are distinctl}^ developed only in old shells.

The shell-structure is fibrous-impuuctate, and the plications of the surface
sometimes tubulose.

Shells of this type of structure are abundant in the Trenton and Hudson
faunas and extend upward into the Clinton group but are not at present known
in any later period.

0 R T H 0 S T R 0 P H 1 A , Hall. 1883.
VI. Group of Orthis strophomenoides, Hall.

PLATK Va, figs. 22-27.

1S57. OHIii!!. Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. -46.

1859. Oiiliis, Hall. Paljeontolog-y of N. Y., vol. iii, pp. 177, 481, pi. xiv. tig-. 2 and pi. xxiii, ti^. 7.

1869. Orthis, Saffohd. Geoldgy of Tennessee, pp. 328, 533.

1883. OttkostnqMa, Hall. Rept. N. Y. State Geol. for 1SS2, pi. xxxvi, figs. 3 .'-34.

This section is represented by impunctate, resupinate shells, having the
external characters of those included in Groups IV and V. In the interior
of the pedicle-valve the muscular area is deeply excavated, very confined, and
limited almost to the narrow space between the dental lamellag. The adductor
scars appear to be extremely minute and linear, while the cardinals occupy
the rest of the area. The margin of this area is thickened and elevated, and
is so contracted as to convey, at first, the impression that it is no more than a
rather large rostral cavity. In the opposite valve the muscular area is sim-
ilarly confined but the quadrilobate character of the impression is very decided.
The lateral components are divided by a strong median ridge, and the entire
area is deeply impressed in the substance of the shell. The cardinal process is
elongate and simple at its posterior extremity, the crural plates and crura strong.

The vascular and ovarian markings are a conspicuous feature of these shells
and are almost invariably developed with remarkable distinctness. In the
pedicle-valve two or three large vascular trunks originate near the anterior
edge of the muscular area, divide a few times in their passage over the pallial
region, the branches rapidly multiplying near the margin. In the opposite
valve the main sinuses are four in number, originating in pairs at the ante-

200 PALEONTOLOGY OF NEW YORK.

lateral margins of the anterior adductors. The outer member of each pair
curves quite abruptly toward the cardinal angle, while the inner members curve
outward and then inward, all ramifying as they approach the margins of the
shell. The umbo-lateral spaces enclosed by the curvature of these sinuses in
both valves, and the central space in the brachial valve, are covered with
linear dendritic ovarian striss.

The only well known representative of this group is the Orthostrophia stro-
phomenoides, of the Lower Helderberg fauna, with which the Orthis Halli, of
Safford, described from the Lower Helderberg of Perry county, Tennessee, is
probably synonymous.

This species is the latest known representative of the impunctate orthids, and
furnishes an interesting example of the persistence of an external form charac-
terizing earlier faunas, accompanied by radical modifications of the interior.
The Niagara species, Orthis fasciata, Hall, and the two species, Orthis mimica
and 0. socialis* described by Barrande, from the Etage D, have interiors very
similar in structure to that of Orthostrophia. These are, however, small,
non-resupinate shells.

PLATYSTROPHIA, King. 1850.

VII. Group of Orthis biforata, (Schlotheim) Davidson.

Terebratulites biforatus, Schlotheim.

PLATE Vb, figs. 1-10.

1820. Terebratulites, Schlotheim. Petrefaoktenkunde auf ihr. jetz. Standpunkt, p. 265.

1830. Terehratula, von Eichwai.d. Nat. Skizze von Podolien. p. 202.

1830. Porambomtea {partim}, Pandeh. Beitr. ziir Geogiio.sie Russlands, p. 96.

1837. Atrypa, Hisingeb. Leth.ta Suecica, p. 76.

•1840. Spirifer, von Buch. Uebei- Delthyi-is, p. 44.

1840. Spirifer, von Eichwald. Silurische Schichten-System von Esthlaml, ji. 144.

1842. Delfhyns, Emmons. Geology of N. Y. ; Rept. Second Distiict, p. 396.

1842. Detthyrls, Conkad. Jour. Acad. Nat. Sci. Phil., vol. viii, p. 260.

1843. I)elthyri% Hall. Geology of N. Y. ; Report Fourth Disti-ict, p. 70.

1843. Spirifer, Castblnau. Essai sur le Syst. silur. de TAmdrique septeutrionale, p. 42.

1844. DtWnjri.% Owen. Geol. Exploration Iowa, Wisconsin, Illinois, pi. l.o.

1845. Delthyris. de Vernkdil. Geol. de la Rnssie, vol. ii, p. 135.

1846. DeWiyris, McCoy. Synopsi.s Silur. Fossils Irelatjd, p. 37.

1847. DeUhyrii, Hall. Palieontology of N. Y., vol. i, p. 131.

*Systt>me Rilurien, vol. v, pi. 63, figs. I. III.

BRACHIOPODA. 201

184S. OrtUs, Davidsox. Bull. Soc. Geol. Krance, 2il ser., vol. v, p. 323.

1848. Spirifem, Phili.ii'S .\xd S.ii.ter. Mam. Geol. Survey Unilert Kiiiffdom, vul. ii, \,. 293.

1850. Platystroplna, Kixa. Moiiogr. Permian Fossils Eng'land, p. lOt).

1851. Orthis, Qdensteut. IIuiull). der Petiefactenkuinle, p. 4St!.

1852. Spirifei; H.\i,i,. PiiUx'ontolog^y of N. Y., vol. ii, p. 65.

1853. Spinfei; McCoy. British Palivoz. Fossil.s, p. 192.

1853. Ort?iis. DAvinso.v. Intioii. Brilisli Fo.ss. Bnichiopoda, plate viii, tir^s. 14fi-148.

1856. OHIiis, Billings. Canadian Naturalist and Geologist, vol. i, p. 206.

1858. DeWiyris, Roohhs Geology of Pennsylvania, vol. ii, p. 820.

1859. Orthis, S.\LTER. Miirclii.<(ni's Silui-ia, 2d ed., p. 210.

1850. Orthis, Hall. Twelfth Rei)t. N. Y. State Cab. Nat. Hist., p. 66.

18GI). OrthU, Li.ND.STRo.M. Gotland's Bracliiopoder, p. 371.

1863. 0)-i*2S, Billings. Geology of Canada, Report of Progress, p. 167.

1865. Plati/strophia, Shaleh. Bull. Museum Comparative Zool., No. 4, ]>. 67.

1866. Orllilt, Salter. Mem. Geol. Survey United Kingiloin, vol. iii, pp. 259, 267, 276.
1871. Orthis. David.son. Britisli Silurian Brachiopoila, p. 268.

1873. Orthis (Platystrnphla), Meek. Geol. Survey Ohio; Palaeontology, vol. i. p. 114.

1874. Ortliis {Platystrophia), James. Cincinnati Quart. Journ. Sci., vol. i. p. 20.

1874. (.H-tliis. Nicholson and Hinde. Canadian' Journal, p. 158.

1875. Orthis. White. Geogr. and Geol. Expl. west 100th Meriil., p. 74.
1875. Orthis, Miller. (Cincinnati Quar. Journ. Sci., vol. ii, p. 25.
1875. Orthis, Nicholson. R(>pt. Pala'Ontology Prov. Ontario, p. 16.
1878. Orthis (Platystrophia), James. The PaUeontologist, No. 1, p. 7.

1880. Orthis. Whlte. Second Ann. Rept. State Bureau Stat, and Geol., Indiana, p. 487.

ISSl. Orthis. White. Tenth Report Slate Geologist Indiana, p. 119.

1883. Platystropliia, Hall. Thirty-sixth Rept. N. Y. State Mus. Nat. Hist., p. 34.

1SS3. IPlatystrojihial. Hall. Rept. N. Y. State Geologist for 18S2, y.l. 34.

1885. 0)ihis, Foerste. Bull. Denison University, vol. i, p. 80.

1S87. Platystrophia, Siialer. Mem. Kentucky Geol. Surv., vol. i, pt. 8, pp. 43. 44.

1889. Orthis, Nettelrotii. Kentucky Fossil Shells, ii. 35.

1889. Platystrophia, Hall. Bull. Geol Society America, vol. 1, p. 19.

The name Platystrophia proposed by Dr. King, ha.s come into very general
use for a group of orthids having a strikingly spiriferoid exterior. The hinge-
line and area are long and straight and near!}' equally developed on the two
valves. Both valves are very convex, the brachial being the more so and
bearing a very strong median fold corresponding to a deep sinus on tlie oppo-
site valve. The valves are marked by strong, sharp plications, which
extend over the fold and sinus, and the external surface is finely granulose,
the latter feature being rarely well retained. This peculiar exterior, so unlike
anything met with elsewhere in the genus Orthis, readily deceived earlier
writers into referring the species to Delthyris or Spirifer,* and Mr. Davidson

*VoN Bucu, 1840, Ueber Delthyris; voN Eicuwald, 1840, Silur. Schichten-systera in Esthland ; Emmons,
1842,Geol. of N. Y. : Rept. Second Dist. ; Conr.ad, 1842, Jour. Acad. Nat. Sci. Phila. ; Hall, 1843, Geol. of N.
Y.; Rept. Fourth District; de Vernedil, Geol. de la Russie; McCoy, Synopsis Silur. Foss. Ireland; Phillips
and Salter. Mem. Geol. Surv. United Kingdom ; Hall. 1847, 1852, Pala;ontology of N. Y., vols, i and ii.

202 PALEONTOLOGY OF NEW YORK.

was the first to demonstrate* the true generic vahie of its internal and more
essential characters. These are not materially different from those already
described in the group of Orthis occidentalis. The delthyrium is open in both
valves, being somewhat larger in the pedicle-valve, and in old and gibbous
shells of Orthis hjnx has often encroached to a considerable extent upon the
umbonal region of the valve. Tlie teeth are thick and very prominent,
tlie muscular area comparatively small, but usually deeply excavated in the
sul)stance of the shell, and not readily divisible into the component scars. In
the brachial valve the cardinal process is a simple linear ridge, always small
and sometimes nearly obsolete. The dental sockets are comparatively small,
the crural plates large and thick, uniting at their inner bases and produced into
a prominent median ridge. The muscular area is quadruplicate and indistinct.
The shell-structure is very compact and finely fibrous, without punctation.

Platystrophfa is represented by a series of forms, all commonly regarded as
referable to Schlotheim's Terebratulites hiforatus, or as presenting only varietal
differences frona this species. The genus appears in American faunas first in
the Chazy and ranges upward into the Clinton and Niagara groups, attaining a
great development in individuals and variety in external form in the Trenton-
Hudson River fauna. It has also a considerable vertical range in the Silurian
of Great Britain, Mr. Davidson citing it from the Caradoc, Upper and Lower
Llandeilo and the Wenlock.f

HETERORTHIS

(nom. propos).

VIII. Group of Orthis Clytie, Hall.

PLATK Vb, figs. 20-31.

18G1. Orthis, Hall. Fdurteenth Kept. N. Y. State Cab. Nat. Hist., p. 90.

1862. Ortlm, Hall. Fifteenth Kept. N. Y. State Cab. Nat. Hist., pi. ii. fig. 4, 5.

1870. Orthis, MiLmn. Cincinnati Quart. Joui-. Sci., vol. ii, p. 34.

187.5. Oiihis, Hall and Whitfikld. Geology of Ohio ; Palaeontology, vol. ii. p. 75, pi. i, figs. 18, 19.

The species Orthis Clytie, from the Trenton horizon at Frankfort, Kentucky,
is the sole representative of a peculiar strophomenoid or lepttenoid exterior
accompanied by internal characters which are distinctly orthoid, but quite pe-

* Bull, de la Sew. Giiol. de France, vol. xxi, 2d ser., 1848.
t Davidson, British Silurian Bi-achiopoda, p. 272.

BRACHIOPODA. 203

culiiir. The shell is transversely oval, with a straight hinge-line and rounded
cardinal extremities ; its form is depressed plano-convex, the convexity of the
pedicle-valve being slight. The cardinal area is about equally developed on
each valve. The surface is ornamented by fine, rounded, radiating striae be-
tween each two of whicli are from two to six much finer radiating lines; all
these are crenulated b}- exceedingly faint growth-lines.

The interior of the pedicle-valve has short teeth with prominent extremi-
ties, and inconspicuous dental lamellx\ The muscular imiM-ession is large and
consists of a small adductor scar situated centrally, and two lateral scars which
are flabellate and greatly elongated, but not uniting in front and enclosing the
adductor as is usual in typical forms of Orthis. These lateral scars are divided
into subordinate impressions, of which tlie outer posterior members may rep-
resent the adjustors. In the brachial valve the dental sockets are obscure, the
crural plates oblique, terminating abruptly at the bases of tlie crura, their
lower part being continued in a low ridge surrounding a short subcircular
muscular area, which is very oliscurely quadrilobate. The cardinal process
has a vertical, sharp, simple, posterior edge, but is much thickened where it
unites with the crural plates, and is produced along the muscular area as a
prominent median ridge. From the ante-lateral mai'gins of the muscular area
radiate six low, somewhat sinuous ridges of similar character to those frequently
seen in members of Group XI. Both valves are considerably thickened just
within the margins, as in many strophomenoids.

The shell-structure is finely fibrous and perforated by minute punctations
which are in general sparsely developed, but most distinctly arranged in
radiating rows corresponding to the surface striae.

Orthis Clytie is the only representative of this type of structure known in the
American Silurian, l)at with it may be associated Sowekby's 0. alternata* and
McCoy's f 0. reirorsistria, both from the Caradoc horizon. The former of these
is a very close ally to the American Trenton form in all its external specific
characters.

* SowERBY, in Murcliison's Silurian System, \t. (i38, pi. xix, fig-. 6 ; 1S39, ;ind Davidson, Silurian Brachio-
poda, p. 264, pi. xxxi, tigs. 1, 3. 7; Supjil. p. 167, pi. xiv, figs. 1-6.

tMcCoY, Britisli Paleozoic Fossils, p. 224, pi. i ii, figs. 12, 13; 18.52, and Davidson, Silurian Brachiopoda,
p. 265, pi. xxxi, figs. 2, 4-6; pi. xxxvi, figs, 30-42; Suppl. p. 185, pi. xiv, figs. 7-16.

204 PALEONTOLOGY OF NEW YORK.

BILOBITES, LiNNE. 1775.

IX. Group of Orthis biloba, Linne.

Anomia biloba, Linne.

PLATE VB, PIGS. 11-19.

1775. Bilohites, Lin.ne. Systema Natui-je, ed. Miiller, vol. vi, p. 825.

1815. Terebratula, J. Sowerby. Trans. Linn. Snc, vol. xii, p. 516.

1826. Tfrcbratula. Hisincjer. Anteckn. Act. Royal Soc, Holm., pi. 7.

1S27. Ddthyrisf Dai,ma.\. Vetensk. Svenska Akad. Hand., p. 124, pi. 3, lig. 7.

1828. Dflthyris, Hlsinger. Biilrajc till Sverig-es geognosi, vol. iv, ji. 220.

1837. Splrifer, von Buch. Alihamll. Konigl. Aka<l. d. Wissensch. zu Berlin, p. 49.

1 837. Di-'lthyri.i. Hi.'^i.vuer. Letha-a Suecica, p. 74.

1838. DtUhyrig, Conrad, Second Ann. Rept. Geol. N. Y., jip. 112, 118.

1838. Terebratida (Delthyrinf) Angelin. Museum Palseont. Suecicum.

1839. Sptrifer, SowEKnv. Murchison's Silurian System, p. 630.

1842. DeWiyris, Conrad. Journ. Acad. Nat. Sci. Phila., vol. viii, p. 262.

1843. Delthyns, Hau,. Geology of N. Y. ; Rept. Fourth District, p. 105.

1847. Spiriftr, de Vkrneuil. Bull. Soc. Geol., Finance, 2d ser., vol. iv.

1848. Orthis, Davidson. Bull. Soc. Geol., Fi-ance, 2d ser., vol. v, p. 321.

1849. /Sjnrifer, Hall. American Journal Science, vol. xx, p. 228.

1850. Dicfelosia, King. Monngr. Pei-m. Fossils, England, p. 106.
1852. Orthis, McCoy." British Palseozoic Fossils, p. 213.

1852. Spirifer, Hall. Paleontology of N. Y., vol. ii, p. 260.

1853. Orthis, David.son. Introd. British Fossil Brachiopoda, p. 10], plate viii, tigs. 141-145.
1859. Orthis, Salter. Murchison's Siluria, 2d ed., p. 543.

1859. Orthis, Hall. Pal;eontology of N. Y., vol. iii, p. 179.

1859. Orthis, Hall. Twelfth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 85.

ISBO. Orthis, Lindstrom. Gotland's Brach. ; Ofver. Kong. Akad. Forhandl., p. 370.

1866. Orthis, Ramsay and Salter. Mem. Geol. Survey United Kingdom, vol. iii, pp. 267, 361.

1868. Orthis, Davidson. Trans. Geol. Soc. Glasgow, Pal. Series, vol. i, pi. 2, fig. 2.

1869. Orthis, Davidson. British Silurian Brachiopoda. p. 206.

1882. Orthis, Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 286.

1883. Orthis [Divoelosia], Hall. Rept. N. Y. State Geologist foi- 1882, plate xxxv.

1884. Orthis, Davidson. Bntish Fossil Brachiopoda, Genei-al Summai-y, pp. 377, 433.

1888. Orthis, Ringuebbrg. Proc. Acad. Nat. Sci. Phila., -p. 134.

1889. Bilohites, Hall. Bulletin Geological Soc. America, vol. i, ji. 21.

Shells small, strongly bilobed. Hinge-line short ; teeth and sockets obscure ;
cardinal process small and simple. Crural plates thin and very long, often
extending as far forward as the commencement of the lobation. Muscular
area indistinct, larger in tlie brachial than in the pedicle-valve. Shell-sub-
stance fibrous and punctated by coarse tubules apparently arranged in radiat-
ing rows.

This group comprises but two species, Orthis biloba, Linne and 0. varica.

BRACHIOPODA. 205

Conrad.* The former has a very considerable range, appearing, according to
DavidsonI in the Caradoc, Lower and Upper Llandovery, Woolhope, Wenlock
and Ludlow formations.

In America it has been found only in the Niagara group, while its congener,
Orthis varica, Conrad, a very distinct species,:j: is confined to the Lower Helder-
berg fauna.

DALMANELLA

Uioin. propo.-?).

X. Group of Orthis testudinaria, Dalman.

PLATE Vb, figs. 2o-39; and PLATE Vc, FIGS. 1-47.

1828. Ortlm, Dalman. Kongl. Vet. Acad. Ilaiidl., pp. 115, 117, pi. ii, tif,'. 4.

1842. Orthis, Emmons. Geology of N. Y. ; Rept. Second Dist., p. 404, tig. 4.

1842. Orthis, Vanuxem. Geology of N. Y. ; Rept. Third Dist., p. 189, fig. 4.

1843. Ortliii. Atrypaf UkhL. Geology of N. Y. ; Rept. Fourth Dist., p. 10,"), fig. t! ; ji. 17."), fig. 4, lunl

p. 271, fig. 4.
1843. Orthis, Conrad. Proc. Acad. Nat. Sei., Pliila., vol. i, p. 133.
1847. Oi-this, Hall. Paleontology of N. Y., vol. i, pp. 117, 118, 120, 128, pi. xxxii, tigs. 1, 2, 5, and pi.

Ixxix, fig. 4.
1852. Orthis, Hall. Palieontology of N. Y., vol. ii, p. 152, pi. lii, fig. 3.

1856. Orthis, Billings. Canadian Nat. and Geol., vol. i, p. 40, tig. 1, and p. 13ii, pi. 2. fig. 5.

1857. Orthlt, Billings. Rept. of Progress Geol. Surv. Canada for 1856, )i. 21)6.

1857. Orthis, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 42, figs. 1, 2, and p. 44, tig. 1.

1859. OrthU, Hall. Palseontology of N. Y., vol. iii, pp. 168-172, pi. xii, fig.s. 1-21, and pi. xiii, figs. 1-12.

1859. Orthis, Billings. Canadian Nat. and Geol., voi. iv, p. 434, fig. 10.

1860. Orthis, F. Roemer, Sil. Fauna westl. Tennessee, p. 62, pi. v, fig. 7.
1860. Orthis, Hall. Thirteenth Rept. N. Y. (^tate Cab. Nat. Hist., p. 121.
1862. Orthis, Hall. Geology of Wisconsin, vol. i, p. 42, fig. 7 and p. 436.
1862. Orthis, Billings. PaliBOzoic Fossils, vol. i, p. 79, fig. 72.

1862. Orthis, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pi. ii, figs. 1-3.

1863. Orthis, Billings. Geology of Canada, pp. 130, 165, 231, 312, figs. 57, 144. 246, 320.

1867. Orthis, Hall. Palaeontology of N. Y., vol. iv, p. 35, 46, 62, pi. v, figs. 1, 2; pi. vi, fig. 1 and

pi. viii, figs. 3-8.

1868. Orthis, Meek and Worthen. Geology of Illinois, vol. iii, p. 373, pi. vii, tig. 6.

1873. Orthis, Meek. Paleontology of Ohio, vol. i, pp. 103, 109, 112, pi. viii, figs. 1-3, 5.

1874. Orthis, James. Cincinnati Quart. .lour. Sci., vol. i, p. 19.

1875. Orthis, Millbb. Cincinnati Quart. Jour. Sci., vol. ii, pp. 20, 22, 24, 30.

*The Orthli acutiluba of Ringdebebg is a form of 0. biloha in which the lobes are veiy ilivergent. All
stages of variation between this extreme and the normal form for the species are readily detected in any
large collection.

+ British Silurian Brachiopoda, p. 208.

I Davidson (Silurian Brachiopoila, p. 207) and Quenstedt (Petrefactenkunde Deutschlands, pi. Iv. figs.
67-70), erroneously regarded this species as indentical with 0. biloha.

206 PALAEONTOLOGY OF NEW YORK.

1S75. Oi-tliif!, White. Geoffr. and Geol. Expl. wost ICOlh Meriii., pj). O"), 72.

1S7S. Orthis, Cmvin. Bull. U. S. Gool. and Geogi-. Surv Terr., vol. iv., p. 72S.

1870. Orthis. Haix. Twenty-eighth Rept. N. Y. State Mus. Nat. Hi.st., p. 150, pi. xxi, tigs. 11-17.

1880. Orfliis, N. H. Winchell. Eighth Ann. Rept. Geol. Nat. Hi.st. Surv. Minnesota, pp. 63, 64.

1882. Orthis. Whitfield. Geology of Wisconsin, vol. iv, p. 2,oS, pi. xii, figa. 5-7 and p. 320, [<\. xxv,

figs. 3, 4.

1882. Ortliis, Hail. Eleventh Rept. State Geologist of In<liana, p. 285, pi. xxi, tigs. 11-17.

1SS3. OHhis. Hall. Report N. Y. State Geol. for 1882, pi. xxxiv, tigs. 1-2-1 and pi. xxxv, figs. 23-27.

1884. Oii?/ifi, Walcott. PaUeontology Eureka Dist., p. 72, pi. xi, figs. 3, 10.

1885. OHlii.i, Foerstk. Bull. Denison University, vol. i, pp. 84, 85, pi. xii, fig. 11 : pi. xvii, fig. 13.
1889. Orthis, Nettlerotu. Kentucky Fossil Shells, p. 37, pi. xxxii, figs. 55-57.

1889. Orthis, Whitfield. Bull. American Mus. Nat. Hist., vol. ii. p. 43, pi. viii, fig. 1-4.
1SS9. Ortli'is, Beeciier and Clarke. Mem. N. Y. State Mus. Nat. Hist., vol. i, No. 1, p. 14, pi. i, figs.

3-11.

Shells plano-conve.\ or subequally liiconvex. Pedicle-valve usually the
deeper, often gibbous, elevated at the umbo and arched over the cardinal area.
Hinge-line generally shorter than the greatest width of the shell. In many
of the species there is a more or less conspicuous, undefined median fold and
sinus on the pedicle and brachial valves respectively. Surface covered with
tine, rounded bifurcating striae.

In the pedicle-valve the teeth are quite prominent, thickened at their ex-
tremities and supported by lamellae which are produced forward circumscribing
a rather short suboval or subquadrate muscular area, which is more or less dis-
tinctly defined in different species and in different conditions of the shell. In
Orthis Meeki, Miller, a somewhat ponderous, biconvex, multistriate variation of
Orthis tesludinaria, it is clearly resolvable into adjustor and diductor scars, the
latter bounding, but not altogether enclosing the impression of the adductors ;
the pedicle-scar is also discernible. In the brachial valve the cardinal process
extends forward as a ridge to the bases of the crural plates, where it is broadened
and continued thence as a median ridge separating the muscular impressions.
The inner surface of this process is divided by a faint median furrow which
produces two lobes at the posterior extremity, and each of these lobes is again
divided, making the process quadrilobate. Sometimes the inner divisions of
the two main lobes have coalesced, producing a strong median lobe and thus
making the process appear trilobate. In some species at maturity, and in
others from abnormal growth this process becomes a broad plug, which fills
the entire delthyrial opening. The dental sockets are small, the crural plates

BRACHIOPODA. 207

often greatly elevated, especially in the plano-convex forms, ami they are not
usually produced into a ridge about the muscular area, but end abruptly.
Muscular impressions quadruplicate, sometimes with radiating ridges extend-
ing from the lateral and anterior margins.

Shell-substance finel}' fibrous and punctate.

This group has a large specific representation and a noteworthy vertical
range. It appears to have had its inception in the Chazy fiiuna, Orthis subaquata,
Conrad, being perhaps the earliest known representative. In the Tren-
ton and Hudson River faunas are Orthis tesludinaria and its close allies, O.
emacerata, 0. Meeki, 0. muUiseda, with a number of other species; in tlic Niag-
ara, O. elegantula ; in the Lower Helderberg, 0. perelegans, 0. concirma, 0. pLano-
convexa, 0. suhcarinata ; in the Corniferous, 0. lenticularis, Vanuxem, not Wah-
leuberg; in the Hamilton, 0 lepida, and in the Chemung, 0. supersles, sp. nov.
With the clo.se of the Devonian the type seems to have disappeared.

There is a considerable difference in the external expression of the forms
included in this group, and the plano-convex species like O. elegantula, 0. Wis-
byensis, 0. basalts, 0. planoconvexa, O.subcarinata, which are readily distinguished
from other members of the section. Some of the internal characters of these
forms are also expressive; the flat brachial valve gives a great elevation to the
crural plates, and the depth of the pedicle-valve makes the dental plates cor-
respondingly high. These internal characters must necessarily vary in their
development with the variation in convexity of the valves but it is doubtful
if any subdivision of the group based upon these features could be of permanent

value.

In these species there is again occasionally found evidence of the secretion
of an apical callosity in the delthyrium of the pedicle-valve, a feature which lias
been observed in Orthis per veta and 0. elegantula. Of additional interest is the
peculiar crenulation or pectination of the inner surface of the high crural plates
in Orthis elegantula, and some other species, a character highly developed in
both teeth and sockets in Tropidoleptus and in Atrypa.

208 PALEONTOLOGY OF NEW YORK.

RHIPIDOMELLA, (Ehlert. 1890.

RHIPIDOMYS, (EnLEHT. 1887.

XL Grouj) of Ortiiis Michelinf, Lt'veillt-.

Terebratula Michelini, Leveille.

PLATE VI, FIGS. 1-lC, 19-21 ; PLATK VIA, FIGS. 1-22 ; and PLATE VII, FIGS. I-IO.

1843. Orthis, Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 71, fig. 1, and p. 105, fig-. 7.

18,i2. Orthis, Owen. Geol. Sui'V. Wisconsin, Iowa and Minnesota, ji. 585, pi. iiia, tig-. 10.

18.52. Orthis, Hall. Palaeontology of N. Y., vol. ii, p. ,iB. pi. xx, fig. 6, and p. 253, pi. lii, fig. 4.

185G. Orthis, Billing.?. Canadian Nat. and Geol., vol. i. p. 134, pi. ii, tig. 1.

1857. Orthis, Hall. Tentii Rei>t. N. Y'. State Cuo. Nat. Hist., )>. 41. tig. 1-5; p. 42, figs. 1, 2 ; p. 46,

and p. 135, fig.';. 1-7.

1858. Orthis, Hall. Trans. Albany Institute, vol. iv, [i. 12.

1858. Orthis, Hall. Geology of Iowa, vol. i, pt. ii, p. 59(3, pi. xii, tig. 4; pp. 4SB, 487, pi. ii, figs. 1-3.

J85S. Orthis, Marcod. Geology of North America, p. 48, pi. vi, tig. 14.

1858. Orthis, Swallow. Ti-ans. St. Louis Acad. Sci., vol. i, p. 218.

1859. OrtMs, Hall. Palaeontology of N.Y., vnl. iii, jip. 162, 164-167, 175, 409, 4S1, pi. x, figs. 1-22;

])1. xa, figs. 4-12; pi. xi, figs. 1-14: pi. xv, tig. I ; pi. xci. tigs. 1-3; pi. xcv,
figs. 1-7; pi. xcva, figs 20. 21.

1860. Orthis, Billings. Canadian Journal, vol. v, pp. 267, 269, figs. 14-16.

1860. OrtMs, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., pp. 78-80, figs. 1, 2.

1860. OrthU, F. Roemkr. Sil. Fauna west!. Tennessee, p. 63, \A. v, fig. 6.

1860. Orthis, Swallow. Trans. St. Louis Acad. Sci., vol. i, p. 639.

1860. Orthis, White. Journ. Bost. Soc. Nat. Hist., vol. vii, p. 231.

1862. Orth'is, White an<l Whitfield. Pi-oc. Bost. Soc. Nat. Hist., vol. viii, p. 292.

1862. Orthis, A. Wixchell. Proc. Acad. Nat. Sci., Phila., vol. xiv, p. 409.

1863. Orthis. Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., pp. 32-35.
1863. Orthis, Swallow. Ti-ans. St. Louis Acad. Sci., vol. ii, p. 81.

1863. Orth'is, Billings. Geology of Canada, p. 369, fig. 385 and p. 3S4, fig. 417.

1864. Orthis, Meek. Palaeontology of Califoi-nia, vol. i. \\ 10, pi. ii. fig. 5.

1865. Orthis, Shalbr. Bull. No. 4, Mus. Coinp. Zool., p. 66.

1865. Orthis, A. Wincuell. Proc. Acad. Nat. Sci., Philadel, p. 116.

1866. Ortiiis, Billings. Catalogue Silurian Foss. Island Anticosti, p. 42.

1867. Orthis. Hall. PaL-eontology of N. Y., vol. iv, pp. 34, 36, 38, 40, 41, 45, 47, 48, 50, 52, 63, pi. iv,

figs. 1-10; pi. v, figs. 4, 6-10; iil. vi, figs. 2, 3; pi. vii. figs. 1, 2, 4 ; pi. viii,
figs. 2, 9, 10; p. Ixiii, figs. 1-5.

1868. Ortliis, Meek and Wohthen. Geology of Illinois, vol. iii, p. 371, pi. vii, fig. 7.
1870. Orthis, A. Wincuell. Proc. American Philosophical Soc, vol. xii, p. 251.

1872. OrtJtis, Meek. Palaeontology of Eastern Nebraska, p. 173, ]il. i, fig. 8.

1873. Oiihi.'!, Meek and Wortiien. Geology of Illinois, vol. v, p. 59], jil. xxv, fig. 4.

1874. Ort/iis, Billing.s. Palaeozoic Foss., vol. ii, p. 32, figs. 14-16; p. 35, pi. iii, fig. 4.

1874. Orthis. Derby. Bull. Cornell University, vol. i, p. 26, pis. v, viii.

1875. Orttiis, WiiiTB. Geogr. and Geol. Expl. we.st 100th Mei-id., p. 125, pi. ix, fig. 5.
1877. Orthis, Muek. U. S. Geological Expl. 40th Parallel, vol. iv, p. 63, pi. vii, fig. 1.

1879. Orthis, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p. 149, i)l. xxi, figs. 18-25.

1881. Orthis; Miller. Journ. Cincinnati Soc. Nat. Hist., vol. iv, p. 8, pi. vii, fig. 8.

1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, p. 320, pi. xxv, figs. 1, 2.

BRACHIOPODA. 209

1552. OHIil.% WuiTKiKi.i). Bull. No. 3, Ameiican Miis. Nut. Hist., p. 4'>, pi. vi, (iffs. 1-5.
18S2. Orfhi.i, Hall. Eleventh Rept. State Geologist of liRliami, p. 285, pi. xxi, ligs. 18-25.
1883. OrthU. H.^ll. Twelftli Rept. State Geologist of Imliana, p. 324, pi. xxix, figs. 1-5.

1883. Oythiis, H.\Li.. Rept. N. Y. State Geologist for 1882, pi. xxxvi, tigs. 1-16, 19-21 and i)l. xxxvii.
figs. 1-4.

1553. Ortkis, White. Twelfth Rept. U. S. Geol. Siii-v. Terr., p. 104, pi. xli, fig. 4.
1885. Ortliis, Foerstk. Bull. Denisou University, p. 83, pi. xiii, tig. 10.

1887. Rldirklmnys, (Ehlert. Fischer's MaTuial ile Conchyliologie ; Brachiopodes, p. 1288.

1888. OrUiis, Herrick. Bull. Dcnison Uiiivei'sity, vol. iii, p. 3S, pi. v, fig. 0.

1889. Oiiliis, Nbttklroth. Kentucky Fossil Shells, p. 39, pi. xxxii, figs. 32-35 ; pp. 4tt, 45, i<\. xvi,

tigs. 4-6, 12-14, 23, 24 and pi. xvii, figs. 33-35.
1889. Oiihis, Simp.sok. American Philosophical So(^, p. 437. fig. 1.

1889. Orlhis, Bbecher and Clarke. Mem. N. Y. State Museum, p. 17, pi. i, figs. 13-18.

1890. Rhipidomella, CEhi.ert. Journal de Conchyliologie.

This is a large and very compact group of orthids, fundamentally character-
ized by the large flabelliform muscular scars of the pedicle-valve, but having in
association with this a number of other peculiarities of importance. The
shells are subcircular in outline, biconvex and sublenticular, with the brachial
valve somewhat the deeper. The hinge-line is short, the cardinal area narrow,
especially on the brachial valve. The surface bears a slight median depression
on each valve, and is covered with fine, rounded, subequal striae which are hol-
low, often opening upon the surface ; these openings probably representing the
broken bases of short tubular spines.

The pedicle-valve bears two strong diverging teeth, planted firmly upon the
valve at the bottom of the delthyrium, and extending upward and outward at
their extremities; and from their bases a more or less strongly defined curving
ridge extends forward, bordering the muscular area. The muscular area
extends from one-third to five-sixths the length of the valve and is deeply
impressed; the pedicle-scar fills the entire rostral cavity; the adductors occupy
a small central scar which is completely enveloped by the great diductors. A
median ridge arises in front of the adductors, dividing the diductors ; .some-
times the former rest upon a general anterior flattening of this ridge, and
in rare instances, the ridge divides the separate components of the adductor
impression. The margin of the entire mu.scular area is thickened and elevated,
and outside of this are deeply pitted ovarian markings.

In the brachial valve the dental .sockets are deep and narrow, the crural
plates extremely prominent, sometimes supporting short crura. The cardinal

210 PALAEONTOLOGY OF NEW YORK.

process is erect, strongly arched on its anterior face, often very thick and
greatly elevated ; the edge of its posterior face is multilobate, the posterior
surface itself having a trilobed appearance. The muscular area is quadruplicate,
comparatively small and usually indistinct. A broad, low, median ridge extends
forward from the base of the cardinal pi'ocess. The shell-structure is coarsely
fibrous and ver}' strongly punctate, the perforations being large and generally
more abundant along the furrows between the striae.

Dr. (Ehlert's term Rh[pidomys==Rhipidomella, which was founded on iheTere-
bratula Michelini, Lt-veille,* must be extended to include what proves to be the
largest of the subordinate divisions of Orthis. Shells of this type, though
attaining their greatest numerical and specific development in the Devonian
and Carboniferous, appeared in America as early as the age of the Clinton
fauna, in the typically developed species 0. circulus. In the Niagara group its
representation is limited to the species 0. hijbrida, a shell which rarely, if ever,
attains the size in America that it does in the Wenlock of Great Britain and
the Island of Gotland. From this point onward the species in the following
faunas rapidly multiply ; the Lower Helderberg fauna containing the forms O.
oblata, 0. discus, 0. eininens, 0. tubulostriata, and that of Oriskany, 0. musculosa,
the largest member of the group, with an extravagant development of the
muscular scars. They reach their culmination in the Devonian, gradually
declining and finally disappearing with the close of the Carboniferous age. In
the faunas of the latter there is occasionally manifested a variation in the ex-
pression of these species, without change in the essential points of structure.
The 0. Penniana, Derby, from the Coal Measures of Itaiti'iba, Brazil, has an
elongate-subovate outline, and a very short hinge-line ; Orthis Pecosi, Marcou,
is a shell of much the same character, while in O. incisiva, Waagen, and
0. dubia, Hall, the hinge-line has become so short that the shell is actually tere-

* Waagen had pi-eviously regarded this species as the type-form of a well defined group in the Car-
Ijoniferous, to which he referred the three species occurring- in the Salt-Range : 0. corallhia, Waagen,
0. Pecosi, Marcou, 0. incisiva, Waagen. (See Menioii's Geolog. Surv. India; Palsontologia Indica,
Ser. xiii, vol. iv (fas. 3), p. 562. 1884.)

The term Ruii'IDOMYS having already been useil for a genus of mammals, Dr. CEulert has proposed the
term Rhipidomella.

BRACHIOPODA. 211

bratulifbnn. In the latter species no trace of the cardinal area remains on
either valve on account of the encroachment of the delthjriura.

In these shells there is occasionally developed a tendency to close the delthy-
riuni of the brachial valve. This is never carried very far, but in some species
where the cardinal process attains a great size, as in 0. Pendope, 0. musculosa,
and others, it more than fills the delthyrial cavity, pressing upward the thinner,
unsupported portion of the cardinal area, where it covers the dental sockets.

SCHIZOPHORIA, King. 1850.
XII. Group of Orthis resupinata, Martin.

CONCHYLIOLITHOS ANOMITES RESUPINATA, Martin.

PLATE VI, FIGS. 17, IS, ii-31 ; AM) I'LATK VIA, FIGS. 23-32.

1809. ConvhyliolitlnLS aiiomites. Martin. Peti-ef. Dei-b., tab. xlix, figs. 13, 14. ""

1813. Aiiomia, Schlotueim. Min. Tasehenbuch, vol. viii, pi. 1, fig. 6.

1820. Teiebratalites, Schlotueim. Die Petrefactenknnde auf ihi-em jetzigen Standiiunkte, pp. 253, 254.

1822. Terehratula, Sowbrby. Mineral Conohology, vol. iv, p. 25.

1822. Uystcrolitlies, Schlotheim. PetiefactenkiiiKie, p. 247.

1836. Spirifera, Phillips. Geology of Yorkshire, vol. ii, pi. xi, (ig. 12.

1840. Spirifera, vo.n Buch. Mem. Soc. Geol. lie France, vol. iv, pi. 10, (ig. 32.

1842. Orthis, Vandxem. Geology of N. Y. ; Kept. Third District, pp. 163, 164.

1843. Orthis, Hall. Geology of N. Y. ; Kept. Fourth Dist.. p. 215.

1843. Orthin, DE KoNlNCK. Description des Aniinaux Fossiles de Belgique, pi. xiii, fig. 9.

1844. Orthis, McCoy. Syn. Carb. Fossils Ireland, pi. xx, fig. 20.

1850. Schizophoria, King. Monogr. Permian Fossils of England, p. 106.

-1851. HysteroUthes, Qdenstedt. Handbuch der Petrefact., p. 484.

1857. OrthU, Hall. Tenth Rep. N. Y. State Cab. Nat. Hist., pp. 45, 110.

1857. Orthis. Cox. Owen's Geological Survey Kentucky, vol. iii, p. 570.

18.i8. Orthis, Hall. Kept. Geol. Surv. Iowa, vol. i, pt. 2, pp. 488, 489, 597.

1859. Orth'is, Hall. Pala>ontology of N. Y., vol. 3, p. 176.

1859. Ortk'is, BiLLi.\(;.s. Hind's Rep. Expl. A.ssiniboine, S.askatchewan, etc., p. 193.

1861. Orthis, Davidson. British Carb. Brachiopoda, j). 130.

1862. Orthis, A. Winchbll. Proc. Acad. Nat. Sci. Phil., vol. xiv, p. 410.

1867. Orthis, Hall. PaUeontology of N. Y., vol. iv, pp. 43, 55, 58, 59, 60.

1868. Orthis, Meek. Transactions Chicago Acad. Sci., vol. i, pp. 88, 90.

1868. Orthis, Meek and Worthen. Geological Survey of Illinois, vol. iii, pp. 423, 424.

1874. Orthis, Dekey. Bull. Cornell Univei'sity, vol. i, p. 63.

1877. Orthis, Hall and Whitfield. U. S. Geol. Expl. 40th Par., vol. iv, p. 265.

1881. Orthis, White. Second Ann. Rept. Bureau Stat, and Geol. Indiana, p. 133.

1882. Oithis, Whitfield. Geology of Wisconsin, vol iv, pt. 3, Palaeontology, p. 326.
18S3. [Schizophoria,] Hall. Ri>])t. N. Y. State Geologist for 1882. pi. xxxvi.

1883. Schizophoria, Hall. Thiity-sixth Rept. N. Y. State Mus. Nat. Hist., p. 75.

1884. Orthis, Wai.cott. Palseontology Eureka District, pp. 114. 115.
1889. Orthis, Nettelroth. Kentucky Fossil Shells, p. 43.

212 PALEONTOLOGY OF NEW YORK.

The species comprising this group have a very close external resemblance to
the resupinate shells included under Groups IV, V and VI. There are still
some differences. In these the hinge-line is shorter, the shells often proportion-
ally narrower, the cardinal area of the pedicle-valve less elevated ; the orna-
mentation of the surface is striate but much more finely ; the striae are hollow,
tubulose and produced into short spines,* as in Rhipidomella.

The interior presents an arrangement of the muscular scars very similar to
that seen in 0. sinuata and its allies. In the pedicle-valve there is a short
subquadrate or obcordate area with thickened, elevated margins, and deeply
sunk in the substance of the shell ; in the opposite valve a less distinctly
defined, quadripartite area. In Schizophoria, however, the adductor impres-
sion occupying the summit of the median ridge dividing the muscular area
of the pedicle-valve, is more distinct, the hinge-teeth are more divergent
and less ponderous ; in the brachial valve the crural plates are much less
divergent and more erect; the cardinal process, which in young shells, has
much the same character as in Rhipidomella, becomes absorbed and thus nar-
rowed with age making a thin and sharp ridge ; concomitant with this change
is the formation, in the delthyrial cavity, of one, two or even three minor ridges
on each side of the original process, so that in old shells the posterior face of
the process appears to be multilobate In the very convex brachial valve, four
(rarely six) deep pallial sinuses take their origin at the anterior margin of the
muscular area, passing forward as broad, simple, subparallel bands, to near the
margin of the valve, where they bifurcate and become arborescent. To these
differences must be added one of distinctive importance, viz., the abundantly
punctate character of the shell-structure.

In America the earliest representative of the group is the species here
described as Schizophoria seneda from the Clinton fauna, this type of structure
being thus coeval with that of Rhipidomella. In the Lower Helderberg fauna
is Orlhis multislriata, Hall, which is followed in the Corniferous limestone by
0. propinqua. Hall, in the Hamilton by O. Tulliensis, Hall, and in the later Devo-
nian by O. lowensis, Hall, 0. impressa, Hall, 0. Macfarlanii, Meek, O. Tioga, Hall,

*See Davidson, British Carboiiifei-ons Brafihioi)oda, pi. xxx, tig. \d.

BRACHIOPODA. 213

0. carinata, Hall. In the Lower Carboniferous are 0. SwaUowi, Hall, 0. resupiiiata,
Martin (?), and in the Coal Measures, 0. resupinoides, Cox.

The term Hysterohthus was applied by some early non-binomial writers to
internal casts of these shells together with others, mostly spiriferoids, having
the same general aspect. The term Hysterolites was used by Linnk * and
ScHLOTHEiMf With more especial reference to the internal casts of Orthis striatula,
Schlotheim, a characteristic member of this group, and tlie name has been
resuscitated by some later writers, but nothing w^ould be gained by the adoption
of this term in place of ScHizornoRiA, especially as its early use was vague and
without generic sisinification.

o^

ORTHOTICHIA

(nom. propos).

XIII. Group of Orthis ? Morqaniana, Derby.

PLATE VU, FIGS. -11-15.

From a personal examination of examples of tliis species, and from Dr.
Derby's detailed description and illustration, | it appears to be very closely
allied in all external and many internal characters to the resupinate shells
constituting the sub-genus Schizophoria. The es.sential point of divergence is
in the presence of a thin, elevated median septum longitudinally dividing the
muscular area of the pedicle- valve, this, with the prominent dental lamellge,
making three vertical plates in this valve. The character thus given to the
interior, as shown in figures 6, 7, 9, 11, plate iii, of Dr. Derby's work, is
altogether distinct from that in Orthis resupiiiata and its allies, for while in
these shells there is often a more or less prominent thickened median muscular
fulcrum, it does not become a septum; futhermore, the muscular area, which
in Schizophoria is deeply impressed and bordered by a thickened margin is not
so in Orthis ? Morganiana, but appears to be on the same level with the general
interior surface and faintly defined at its anterior edge. In the brachial valve
the species has the multipartite cardinal process and the arrangement of mus-

* Museum Tes.'iinuitiuni, p. i*0, 1755.
1 Die Petiefactenkunde, p. 247, 1820.

X Bulletin of the Cornell University, vol. 1, i^fo. 2, pp. 29-32, pi. iii, tigH. 1-7, 9, 11, 34 ; pi. iv, ligs. G, 14,
15. 1874.

214 PALEONTOLOGY OF NEW YORK.

cular scars as in Schizophoria. Although Dr. Derby emphasizes the latter feat-
ure as of especial importance on account of its being composed of three pairs
of scars, it has been shown that this area in Schizophoria is of the same char-
acter wlien distinctly defined, a condition not often observed. (See Orthis
impressa, Plate VI a, fig. 28.)

Orthis? Morganiana apparently rejjresents a passage-form between Schizophoria
and Enteletes, though its predominant characters are distinctly orthoid.*
Dr. Waagen refers to the same group his species, Orthis mar morea and 0. Derbyi,
from the Carboniferous beds of the Salt-Range of India; 0. ? Morganiana is
from the Coal Measures of Itaituba, Brazil.

ENTELETES, Fischer de Waldheim. 1830.

(Waagen, emend. 1884.)

XIV. Group of Enteletes Lamarcki, Fischer de Waldheim.

PLATE VII A, FIGS. «-54.

1835. Clioristiies (partim), Fischer de Waldheim. Programme sui' la Chori.stites.

1830. Enteletes, Fi.scher de Waldheim. Oryctogi-. du Gouv. de Moscou, p. 144, tab. 2li, fig-s. 6, 7.

1837. C/ioriatifes (partim), Fi.schek de Waldheim. Oryctogr. du Gouv. de Moscou, p. 141, tab. 24,

tigs. 10, 11.
1842. Teiebratula, v'Orbigny. Voyage dans rAmt-rique Meridionale, Pal., p. 45, pi. iii, tigs. 14-16.
184.1. 'SpiHfcf ipartim), de Verneuil. Gi'ol. de la Rassie d'Europe et des Montagues de rOiiral, p. 152,

pi. vi, tigs. Sa, b.
1852. i^pirifer. Hall. Stansbury's Rept. Expl. Great Salt Lake, \i. 409, pi. iv, tigs. 3 a, b.

1865. S^yntrieUufma, Meek and Worthen. Proc. Acad. Nat. Sci. Phila., p. 277.

1866. lihyn.choiuUa, Geinitz. Carbon, und Dyas in Nebraska, ji. 37, pi. iii, tigs. 1-4.

1866. Syntnelasma, Meek. Geol. Survey of Illinois ; Paheontology, vol. ii, p. 223, fig. 36 ; \t. 324,

tig. 37.

1872. Syiitrielaxma, Meek and Worthen. PaliBontoIogy of Eastern Nebr.aska, p. 117, ]>1. vi, tig. 1;

pi. viii, tig. 12.

1873. Syntnelasma, Meek and Wortiik.\. Geol. Survey of Illinois ; Palaeontology, vol. v, p. 571,

pi. xxvi, tig. 20.

1874. Syyitrielasnux, Derby. Bull. Cornell Univei-sity, vol. i, p. 62.

1876. OrtliiK, TRAUT.SCHOID. Die Kalkbriiche von Mjatschkowa II, p. 70, pi. viii, tig. 3.

1883. Syntriekuima, Kay.ser. Richthofen's China, vol. iv, p. 179, pi. xxiv, figs. 2, 3

1884. Enteletes, WAAtiSN. Mem. Geol. Surv. India ; Palaenntologia Indica, Ser. xiii, i, iv (fas. 3), p. 550.
1884. Enteletes, Davidson. General Suniinary of British Fossil Brachiopoda, p. 377.

Diagnosis. "Coquille sub-arrondie ressemblant pour la forme a une Trrc-
bratule, presentant de petits bees sur les deux valves, mais la charnirre est

* See remarks by Mr. Meek given in Derby's papci-. loe. cit., and by Waagen, Salt-Range Fossils,
Brachiopoda, p. 564.

BRACHIOPODA. 215

tollement unie et close, quo les deux bords avancent uu peu au dessus do la
coquillo. La cliarnirre est tn'-s courte." — Fischer de Waldheim, 1880 {loc. cit.).

" The general outline of the shells is more or less globular, with mostly very
strongly inflated valves. The hinge-line is short, never projecting at the ex-
tremities ; both valves are more or less strongly plicated radially.

"The ventral valve is always smaller than the dor.sal one The area ol' tlie
ventral valve is sonietimos high and strongly reclining, sometimes not ; but
laterally little extended, according to the short hinge-lino. It is cut open in
the middle by a tolerably large triangular fissure, which is never covered up
by a pseudo-deltidium.

" The dorsal valve is always larger than the ventral one, with a strongly
bent-over and sometimes roUed-in beak. The area is mostly small in this
valve and even sometimes linear. The deltidial fissure is smaller than in the
other valve.

" Both valves are covered all over with a very fine radial striation, similar
to that occurring in man}^ .species of Orthis, and it appears not improbable
that also in Enteletes fine hair-like spines were dis-seminated irregularly over
this striation. The minute structure of the shell is punctate." * * *

" Internally the ventral valve bears two strong elongated teeth on both sides
of the triangular fissure, supported by very strong dental plates, which extend
from the apex toward the front of the valve; bat instead of diverging they
approach each other toward the middle of the valve, bending around, either
with a gentle curve or a sudden bend. Between these dental plates, beginning
as a low ridge at the apex, a thin blade-like median septum extends ; it is
highest toward the middle of the valve and then suddenly terminates."

" The dorsal valve has interiorly two very strong septa, Avhich extend on
both sides of the deltidial fissure, and project for a certain distance, strongly
diverging into the interior of the valve. They support strong and long curved
crura, which have exactly the shape of a boar's tusks. They are laterally
compressed and bear on their lower and inner side a sharp prominent ridge.
The dental sockets are placed exteriorly to the origin of the crura. In the
middle, at the apex of the valve, a small cardinal process is observable, having
the form of a short narrow ridge." — Wa.\gen (loc. cit).

Type, Eiiteleies Lamarcki, Fischer de Waldheim, Upper Carboniferous lime-
stone.

American example, Spirifer hemiplicatus, Hall, Upper Carboniferous.

216 PALEONTOLOGY OF NEW YORK.

Observations. Dr. Waagen has shown the necessity of adopting for these
shells the early term Enteletes, as Fischer's figures accompanying his diagno-
sis prove to be of the well-known fossil Spirifer Lamarcki, although his descrip-
tion, sufficient for the pui-poses of that time, is of little value in establishing
his genus. The regret expressed by Dr. Waagen at being compelled to super-
cede Meek and Worthen's term, Syntrielasma, will be generally felt, especially
as these authors had characterized their genus very accurately and illustrated
it with care ; they also demonstrated its close relationship to Orthis. This
appears externally in the bi-perforate cardinal areas, uncovered delthyria, and
tubulo-striate surface. It has already been suggested that these forms are
linked to the punctate resupinate species of Orthis (Schizophoria) through the
Orthis? Morganiana of Derby. Though the shells are extremely globose, and
their sharply plicated surface is not to be found among species of the genus
Orthis, they are distinctly resupinate ; the interior characterized by the great
development of the crural plates in the brachial valve, and the three plates in
the opposite valve, which are orthoid features carried to an extreme develop-
ment. The cardinal process is small, erect and multilobate. The muscular
markings have not been determined ; it is evident from analogy with Schizo-
phoria that in the pedicle-valve the muscular area was limited to the very
narrow space between the two lateral septa and was divided by the median
partition; in the brachial valve the wider space between the crural plates is
also divided by a faint median ridge.

Before Dr. Waagen's study of the Salt-Range faunas but two species of this
genus were well known ; one the Enteletes Choristites or Spirifer Lamarcki, of the
Upper Carboniferous limestone of Mjatschkowa, Russia; the other Syntrielasma
hemiplicatum, Hall, sp., from a corresponding horizon in America.

Dr. Waagen has added seven species, and proposed a subdivision of the genus
as follows: ventrisinuati ; A, group of Enteletes hemiplicaius, Hall (sp.), i. e.,
forms with a ventral sinus : dorsosinuati, forms with a ventral fold ; A, group
of Enteletes f err ugineus, Waagen, subequally convex shells ; B, group of Enteletes
pentameroides, Waagen, extremely gibbous species of pentameroid aspect. To

BRACHIOPODA. 217

the second division is referred the shell described by Geinitz * from the Upper
Carboniferous or Permian of Nebraska, as Rhynchonella angulata, Linm'-. Ac-
cording to Mkek and Waagen, the Carboniferous species, Terebratula Andii and
T. Gaudryi, of u'Orbig.ny, from Bolivia, are to be referred to Enteletes.

Future study of the species of Orthis which have not been accessible during
the preparation of this work, will no doubt necessitate the establishment of
still other groups of equivalent value to those here proposed ; but there will,
of course, always remain forms of intermediate structure which can not be in-
cluded in any strict classification. It is, however, gratifying to find relatively
so few species which can not be placed under the foregoing subdivisions.

There is a small group of shells exemplified by such forms as Orthis punctata,
de Verneuil, from Gotland, and 0. pundostriata. Hall, from the Niagara fauna,
which have a true orthoid interior but a peculiar external form, and a surface
covered by radiating rows of circular superficial punctae, very similar to those
marking the genus Porambomtes. Other species for which it is difficult to find
a place in this grouping are a few of the type of 0. Bouchardi, Davidson, 0.
Nisis, Hall, and O. rugiplicata. Hall. The early species which have been refer-
red to Orthis require especially careful consideration. From later study of
the species described by Mr. Billings, from the Quebec group, examples of which
have been kindly furnished by the Directors of the Geological Survey of Canada,
and of the Redpath Museum of Montreal, it is shown that one of them, 0.
gemmicula, must be removed to another genus ; another, 0. apicalis, is very
doubtfully an Orthis ; while 0. Mycale and 0. Tritonia appear to have no cardi-
nal process in the brachial valves ; 0. Hippohjte, wliich in external features
might be classed with the punctate group of 0. testudinaria, is an impunctate
shell. The species 0. Armando and 0. Corinna have a leptasnoid form, and
their relations are evidently quite remote from typical Orthis. These species

* Carbon, and Dyas in Nebraska, p. 37, pi. iii, tig's. 1-4. Mr. Meek regarded this iis idenlii-al with
Buteletes hemiplicatus (Report PaU-eontology of Eastei-n Nebraska, p. 178. 1872)

218 PALEONTOLOGY OF NEW YORK.

together with 0. platys, Billings, from the Chazy, 0. Saffordi, sp. nov., and
probably 0. Holstoni, Safford, from the Trenton, form a small group distin-
ouished bv its peculiar exterior, though the internal characters of the species
are still undetermined. To establish the true generic value of all these forms
will require much patient work both in the field and in the laboratory.

The orthids occurring in primordial faunas have in so many instances shown
a comprehensive structure, having characters which individually are distinctive
of Orthis, Orthothetes, Clitambonites, Scenidium, etc., that it may be ques-
tioned whether any of these primordial forms can be included under Orthis
according to the strict definition of the term, or even under any of the sub-
divisions here proposed.

The development of the'purfctated shell-structure in this genus is a peculiar
phenomenon.* In eight of the thirteen proposed subdivisions of Orthis, the
shell-structure is prismatic but impunctate. So f\xr as now known there is not
an impunctate Orthis in the faunas later than the Silurian. On the other hand
the punctate species are decidedly in the minority in Silurian faunas, attaining
their great numerical development in the Devonian. The first appearance of
punctation is along the line of the 0. testudinaria group (Dalmanella), but evi-
dence is still required to show that some of the earliest species included in this

* Thin sections of these .shells have been made whenevei- material has been favorably preserved or in
siitfirient quantity to allow it. and no evidence has been found of an indiscriminate or sporadic appearance
of this punctation, thoug'h it has, natui-ally, been impossible to study the shell-structure in evei-y species
examined. It was originally a part of the plan and pui'pose of this work to take up the study of the minute
.-ihcll-.'itructnre in connection with the generic studies, and to include the result of the investifrafion in this
volume, fus a part of the conlribntion to our knowledge of the Palsozoic Brachiopoda. The lapse of nearly
twenty years fi-om the commencement of this work till it was again taken up, in 1888,t has brought much
new material for c insideration, while the studies and publications of numerous authors have served to
present the subject in new aspects, and at the same time to demand a somewhat ditferent treatment from
that originally contemplated. Owing to these conditions the study of the shell-structure has been postponed
for the (iresent, but it is the ultimate purpose of the author to take up as a special subject the examination
of the minute shell-structure in the different genera of Palaeozoic Brachiopoda.

t The work of a revision of the genera of the Palieozoic Brachiopoda was began soon after the completion and pub-
lication or Volume IV of the Pal.TontoIosy of New York, and thirty plates, beginning with illustrations of the generic
group of Orthis hart ah-carty heon litliographcrt, from drawings chiefly made by Mr. E. P. WiirrFiELD, when it became
ni-i-ussary to suspend the woj-k. These plates, originally numberoil from aV to XXXVI, were mostly lithographed by Mr.
I'nii.ir .Vst; two of them by .Swintox, two by UitMANN and two by Bei^oman, between the years 1S70 and 1876. Of
these iilatcs aV and V have been cancelled, and, with large additional material and accumulated information, have been
substituted by V, Va, Vr, Vc. The original plates, from VI to XIX, are included in this volume, .and are supplemented by
VIA, VIIa, XIa, XIb, Xlc, Xll), XVa, XX.

BRACHIOPODA. 219

group are actually punctate. It is not surprising to find some primordial
species of Orthis, for example O. Billingsi (Protorthis), affording indications of
a punctated shell, which, with other characters, may be interpreted as showing
relationship to Clitambonites and the streptorhynchoids in which a punctate
structure is never wanting.

It should not be forgotten that a grouping of the species of Orthis was made
by DE Verneuil in 1845,* and by Qoenstedt in ISTl.f The very broad concep-
tion of generic values which generally prevailed at the date of the former work,
but which at the latter period were maintained by few students, renders these
groupings of little value in the present state of our knowledge. In de Ver-
neuil's classification, based upon thirty-five species and varieties of " Orthis,"
were two groups of the first order, A, Sinuate, corresponding to King's Schizo-
PHORiA, and B, non-Sinuata. The latter was divided into a', striates, b', plicosa.
The striata were again divided, a-, arcuostriata, in wliich the delthyrium is open,
and b", rectostriatcz, in which the delthyrium is closed. The former of these
included the a', uniarca,, with a rudimentary area on the brachial valve (ex.
0. elegans, Bouchard), and b', biarecz, with areas developed on both valves. Of
the biarea were two subdivisions, a\ filiarea (ex. O. Micheliiii = RuiPivo-
MELLA ; O. tetragona =^- Schizophoria) ; b', elegantulcz (ex. 0. eleganlula, 0. parva
= Dalmanella). Of b', redostriata, were also the subdivisions a', uniarea, and b',
biarea, and of the former of these two groups a*, with three or more secondary
striae in the furrows (== Orthothetes) ; b', witli but one or two such striae
(=Meekella, Streptorhynchus, Derbva, Orthothetes) ; of the latter, biarete,
were a\ GoNAMBONiTES (= Clitambonites), and b', Pronites (^Clitambonites
and Orthisina). The b', plicoscz, were divided into those with simple plications
(0. calligramma), and those with dichotomous plications (0. extensa, Pander).

Quenstedt instituted three principal divisions of his oRTiiiDiE: (1) ventriplexa,
with convex pedicle-valve; {'!) ventricavce or expanse, with concave pedicle-valve;
(3) dorsicav(Z, with concave bracjiial valve. Representatives of the first in-
clude Schizophoria, Porambonites, Orthisina, Clitambonites, Streptorhynchus,

*Geol. Russ. et de3 munt. de I'Ui-al.

t Petrefactenkuiule Deutschlanils: Brachiopodeii.

220 PALEONTOLOGY OF NEW YORK.

BiLOBiTES, Orthis, Dalmanella, Rhipidomella, Orthothetes, Anoplotheca, Lep-
TOCtELiA, Tropidoleptus. In the second group were placed species belonging to
the genera Brachyprion, Strophodonta, Plectambonites, Lept^na, Productus,
Chonetes, Stricklandinia; in the third were Strophomena, Strophonella and
Orthothetes.

LIST OF GENERA AND SPECIES.

The subdivisions here proposed for the genus Orthis, in its broader signifi-
cance and usual acceptation, some of them under old names and others under
new, are well founded in nature. This arrangement is the result of a careful
study of a very extensive series of the American representatives of this genus,
and of the nearly two hundred species which are currently referred to Orthis,
a very large percentage will readily take their places in the proposed classifi-
cation. It will be borne in mind that after the elimination of synonymous
terms there still remain a considerable number of names, founded upon imper-
fect or obscure material, which are of little aid to the student of palaeontology ;
others, upon fossils of great rarity or from horizons of uncertain age. In the
following list of American species, which is appended in order to show the
adaptability of this grouping, nearly all the members have been studied from
actual specimens, the star preceding the names indicating this fact ; the other
species included being only those of which the original descriptions and figures
have afforded some definite clue to their relation with these groups.

BRACHIOPODA.

221

ORTHIS, Dalman (as restricted).
I. Group of Orthis callactis, Dalman.

* O. costalis, Hall Chazy.

t* 0. ortliambonites, Billings Quebec.

* 0. Euryoiie, Billings Quebec.

* O. Hippolyte, Billings Quebec.

* 0. disparilis, Conrad Trenton.

* 0. tricenaria, Conrad Trenton and Hudson River.

* 0. Habellulum, Sowerby Niagara.

* 0. Davidsoni, de Verneuil Niagara.

* 0.

* 0.
*[?J0.

* 0.

* 0.
*0.

*[?]0.
*0.
*0.

* 0.
[??] 0.

PLECTORTHIS

II. Group of Orthis plicatella, Hall.

aequivalvis, Hall Trenton and Hudson River.

plicatella, Hall Trenton and Hudson River.

Ella, Hall Hudson River.

fissicosta. Hall Hudson River.

Jamesi, Hall Hudson River.

Kankakensis, McChesney Hudson River.

sectostriata, Ulrich Hudson River.

triplicatella, Meek Hudson River.

Whitfieldi, N. H. Winchell Hudson River.

dichotoma. Hall Hudson River.

aurelia, Billings Lower Devonian.

t This species was identified by Billings with 0. orthavihonltes. Pander ; but that author used Ortham-
BONITES only .'IS a g^eneric term, thoujjli it was subsequently taken by von Blcii and voN EicuwAH) as a
specific desitrnation to include all the species lefeired by Pandkr to this {jenus. As a specific term, it must,
therefore, be accredited to voN BuCH, and it is synonymous with some one (it is impossible to say which) of
Pander's species. It appeal's to be quite distinct from the 0. calligramma, var. orthambonites, de Verneuil,
with which the Quebec species is compared by Mr. Billings, and it should therefore receive a new name.

222

PALEONTOLOGY OF NEW YORK.

DINORTHIS

(Horn, propos).

III. Group of Orthis pectinella, Emmons.

* 0. pectinella, Emmons Trenton.

^•P^±^llL., Hal. Trenton.

* 0. Svveeneyi, N. H, Winchell Trenton.

0. Iphigenia,

* 0. porcata,
0. retrorsa,

* 0. subquadrata

* 0. detlecta,

* 0. recta,

* 0. loricula.

PL^SIOMYS

(nom. propos).

IV. Group of Orthis subquadrata. Hall.

Billings Trenton.

McCoy Trenton and Hudson River.

Salter Trenton and Hudson River.

Hall Trenton and Hudson River.

Conrad Trenton.

Conrad Trenton.

sp. nov Trenton.

0. Battis,
0. imperator,

* 0. bellarugosa,

* 0. borealis,
0. Lonensis,

* 0. insculpta,

* 0. occidentalis,

* 0. sinuata,
0. Scovillii,

* 0. Maria,

* 0. Daytonensis,

* 0. fausta,

HEBERTELLA

(nom. propos).

V. Group of Orthis sinuata, Hall.

Billings . Quebec.

Billings Cliazy.

Conrad Trenton.

Billings Trenton.

Walcott Trenton.

Hall Hudson River.

Hall Hudson River.

Hall Hudson River.

Miller Hudson River.

Billings Anticosti.

Foerste Clinton.

FoERSTE Clinton.

BRACHIOPODA.

223

ORTHOSTROPHIA, Hall. 1883.

VI. Group of Orthis strophome.noides, Hall.

*[?)0. fivsciata, Hall Niagara.

* 0. Halli, Safforu Lower Helderberg.

* 0. strophomen-

oides, Hall Lower Helderberg.

PLATYSTROPHIA, King. 1850.

VII. Group of Orthis biforata, Schlotlieim.

* 0. biforata, Schlotheim Chazy — Clintou.

* 0. acutilirata, Conrad Hudson River.

* 0. crassa, James Hudson River.

* 0. laticosta, Meek Hudson River.

* 0. lynx, VON Eichwald Hudson River.

HETERORTHIS

(uom. propos).

VIII. Group of Orthis Clytie, Hall.

* 0. Clytie, Hall Trenton.

BILOBITES, LiNNE. 1775.

IX. Group of Orthis biloba, Linne.

* 0. biloba, Linne Niagara.

* 0. varica, Conrad Lower Helderberg.

DALMANELLA

(nom. propos).

X. Group of Orthis testudinaria, Dalman.

* 0. Electra, Billings Quebec.
*[?J0. EvadnB, Billings Quebec.

224

PALEONTOLOGY OF NEW YORK.

* 0. Macleodi,

Whitfield

Calciferous.

* 0. snbaiquata,

* 0. Minneapolis,

Conrad

N. H. WiNCHELL

Cliazy — Trenton.
Trenton.

0. gibbosa,

* 0. perveta,

* 0. Stonensis,

Billings

Trenton.

Conrad

Safford

Trenton.
Trenton.

* O fpstndinaria.

Dalman

Trenton — Hudson River

* 0. bellula.

Meek

Hudson River.

* 0. crispata,

Emmons

Hudson River.

* 0. emacerata,

Hall

Hudson River.

* 0. Meeki,

Miller

Hudson River.

* 0. mnltisecta,

Meek

Hudson River.

* 0. elegantula,

var, pai-va.

Foeuste

Clinton.

* 0. elegantula.

Dalman

Niagara.

* 0. arcuaria,

sp. nov

Niagara. '

* 0. concinna,

Hall .

Lower Helderberg.

* 0. perelegans,

Hall

Lower Helderberg.

* 0. planoconvexa.

, Hall

Lower Helderberg.

* 0. q 11 ad ran s,

* 0. subciirinata,

Hall

Lower Helderberg.
Lower Helderberg.

Hall

* 0. lenticularis,!

Vandxem, non Wahlenberg,

Upper Helderberg.

* 0. lepida.

Hall .

Hamilton.

* 0. infera.

Calvin-

Chemung.

* 0. Leonensis,

Hall

Chemung.

* 0. superstes.

sp. nov.

Chemung.

RHIPIDOMELLA, (Ehlert. 1890.
XI. Group of Orthis Michelini, Leveille.

* 0. circulus, Hall Clinton.

* 0. uberis, Billings Anticosti.

* 0. hybrida, Sowerev Niagara.

* 0. assimilis. Hall.. Lower Helderberg.

t The speciKc. ii;ui)i> lenlicularis hnving- already been used for a species of Orthis, the name should be
changed to Orthin UnUfonirix, ILilL Si-e Repm t of (lie Fourth Geolofjical Dititi-ict of New Yoi'k, paye 175.

BRACHIOPODA. 225

0. discus, IIali Lower Helderberg.

* 0. eminens, Hall Lower Helderber";.

* 0. oblata, Hall Lower Holderber-;.

* 0. tubulostriiita, Hall Lower Helderberj!;.

* 0. Cumberlandia, Hall Oriskany.

* 0. musculosa, Hall Oriskany.

* 0. alsus, Hall Schoharie.

* 0. peloris, Hall Schoharie.

* 0. Cleobis, Hall Corniferous.

* 0. Livia, Billings Corniferous.

0. Semele, Hall CorniCorous.

* 0. Vanuxemi, Hall Hamilton.

* 0. Vanuxemi, ^t t^r i ,

var. pni.hriiu. Herrick Wavcrly.f

* O. cyclas, Hall Hamilton.

* 0. idonea, Hall Hamilton.

* 0. Leucosia, Hall .... Hamilton.

* 0. Penelope, Hall Hamilton.

* 0. solitaria, Hall Ha.milton.

* 0. suborbicularis, Hall Hamilton.

* 0. Pennsylvanica, Simpson Chemung.
[?] 0. cuneata, Owen Devonian.

0. Lucia, Billings Devonian.

0. occasus, Hall Waverly.

0. subelliptica, White and Whitfield Waverly.

* 0 Missouriensis, Swallow Choteau.

* 0. Burlingtonensis, Hall Burlington.

0. Dalyana, Miller /Burlington.

* 0. Thiemii, White Burlington.

0. Clarkensis, Swallow Keokuk.

* O. Oweni, sp. nov Knobstone.:]:

* 0. dubia. Hall St. Louis.

t There i^s a larger Ibrin of Okthis in the Wjiverly of Ohio, which has a \eiy gibbous brachial valve,
and can not be regarded sis identical with this variety of 0. Vamaemi.

I The "Knobstone group" of 0wE>f, in Kentucky and the southern part of Indiana, in its lowest mem-
bers, has been generally regjirded as of the age of the Waverly of Ohio. Its upper member h.os been
paralleled with the Keokuk, but the limitation between these formations is not always well defined or easily
determined.

226 PALEONTOLOGY OF NEW YORK.

O. Nevadensis, Meek Carboniferous.

* 0. Pecosi, Marcou Coal Measures.

* 0. Peniiiana, Derby Carboniferous.

SCHIZOPHORIA, King. 1850.
XII. Group of Orthis resupinata, Martin.

* 0. senecta, sp. nov Clinton.

* 0. multistriata, Hall Lower Helderbere;.

[?j 0. peduncularis, Hall Lower Helderberg.

* 0. propinqua, Hall Corniferous.

* 0. Macfarlanii, Meek Upper Devonian.

* 0. Tulliensis, Hall Tully.

* 0. lowensis, Hall Chemung.

* 0. carinata, Hall Chemung.

* 0. impressa, Hall Chemung.

* 0. Tioga, Hall Chemung.

* 0. Swallovi, Hall Burlington.

* 0. resupinata, Martin Lower Carboniferous.

* 0. resupinoides, Cox Coal Measures.

ORTHOTICHIA

XIII. Group of Orthis (?) Morganiana, Derby.

* 0.(?) Morganiana, Derbv Coal Measures.

ENTELETES, Fischer ue Waldheim. 1830.
XIV. Group of Enteletes Lamarcki, Fischer de Waldheim.

* Enteletes

hemiplicatus, Hall Coal Measures.

BRACHIOPODA. 227

.SUPPLEMENTARY NOTE ON THE GENUS ORTHltJ.

In the foregoing list of species, the form currently known in this country as Orlhis flabel-
luluin, from the Clinton-Niagara fauna, is arranged with the typical division of the genus.
In a previous provisional arrangement it was placed under the group Di.nokthis, in associa-
tion with 0. pectinella. There are excellent reasons for its position in either association. With
the typical orthids it agi'ees in the simple plications of the surface, and in the character of
the muscular impressions in both valves. Attention is especially directed to this conformity
in the pedicle-valve, where the outline of the muscular area is the more variable throughout
the entii-e genus; and the figure 40, upon Plate V,* shows its oval form and restricted ex-
tent, similar to that seen in Ortim ccdLigramma, var. Davidsoni (fig. 5), and Orthis costalis (fig.
15.) The species is how^ever a distinctly resupinate shell, as shown on Plate V, fig. 39 ; the
pedicle-valve, in the umbonal region, is quite as deep as the brachial, but is gently depressed
over the pallial region, while the brachial valve remains convex throughout. To associate
this species with the typical forms of Orthis, would open that division to the reception of
resupinate shells, thus destroying its homogeneity. On the basis of external characters the
shell belongs to tlie group Dinorthis, but it does not, agree with Orthis pectinella in its mus-
cular impressions, so that it must be regarded as a form connecting the typical Orthides
with Dinorthis ; though, in geological time, appearing at the end of the two groups.

The original identification of this Niagara species as Orthis flabellulum, (a) .* was made
in 1843,t from comi^arison with the figure given by Sowerby, in Murchison's .Silurian Sys-
tem (pi. xxi, fig. 8). This figure did not indicate with clearness either the resupination of
the shell or the outline of the muscular scars, and the identification, made with iluubt, has
been accepted as final.

The elaborate illustration of the British species of this name given bj' Mr. Damdson at a
later date,+ shows that it is strongly resupinate and has a subipiadrate muscular area in the
pedicle-valve, features which at once associate it with Dinorthis, and it is further evident
that it is a close ally in all its characters with the American species 0. pectinella, though in
the latter the bifurcation of the plications, whicli appears to be normal for 0. flabellulum,
.Sowerby (var. /3), is of less frequent occurrence. These two forms are from equivalent
horizons. For nearly fifty years an erroneous identification, though made with the best
lights of that time, and expressed with doubt, has been current in American literature.
In the Twentieth Report on the New York State Cabinet of Natural History (18()7, p. 397),
the term Orthis flabdlites, Hall, was used for the species in a list of the fossils occurring in the
limestones of the Niagara group in Wisconsin, Illinois and Iowa ; and although no discussion
or explanation of the reference was there given, the name was intended to supercede the use
of O. flabellulum.

' Ad additional figure of this valve, showing these characters with greater distinctness, will be given .upon a supple-
mentary plate at the close of this work.

t Qeology of Sew York; Report Fourth District, p. 107.
X 1359. Silurian Brachiopoda, pi. x.xxiv. figs. l-12a.

228

PALEONTOLOGY OF NEW YORK.

The en'oueous reference of this species has but. recently been corrected, iti part, by Mr.
A. F. FoERSTE, t who has pointed out some of the differences already mentioned, and has
proposed to retain the species (as it stands in the list) associated with O. caUigramma, var.
flabelliles. While indisposed to continue a resupinate shell in this association, tlie necessity
of another name for the American species is evident.

The following arrangement will indicate the relations of Orthis flahelUtes to the group of
Orthis callactis, Dalman, and that of Orthis pectinella, Ennnons :

ORTHIS, Dalman (as restricted).
I. Group of Orthis cALi-AfTis, Dalman.

* 0. costalis. Hall Chazy.

* O. orthambonites, Billings Quebec.

* 0. Euryone, Billings Quebec.

Billings Quebec.

Conrad Trenton.

Conrad Trenton and

JIudson River
DE Yernedil Niaarara.

* 0. Hippolyte,

* 0. disparilis,

* 0. tricenaria.

* O. Davidsoni,

D I N 0 R T H I S .

IV. Group of Orthis pectinella, Emmons.

* O. pectinella, Emmons Trenton.

* O. pectinella,

var. semiov.ilis, Mall Trenton.

* O. Sweeneyi, N. H. Winchkll, Trenton.

» O. tiaViellites, Hall. Niagara.

t Proceedings Boston Society Natural History, vol. xxiv. pp. 308-312. 1890.

The following tabular arrangement of the generic subdivisions of the
Onrnm^ will show the geological range of each one of the subdivisions, and
of the entire family :

BRACHIOPODA.

229

►6

IS

o

O

o

cc =: -^ tj

N
O

»'i —

— '

i—t

►T3

O

^

fa

V

ft

>

H

13

>

s

^

O

W

?3

r

a

o

>'» ~

ts
a

o

^

f

<4

o

O

-3

I I

I

Lower Cambrian.
Middle Cambrian.
Upper Cambrian.

Cliazy.
Trenton.
Utica.
Hudson liiver.

< I][|I<JU.
^ : -.ir.T.

I . r Ilcl<Ieilierg.

Oribkany.

Upper Heblerbcr^'.

Hamilton.

Chcmtuig:.

Waverly.

I'.urlin^tnii.

K'«'i>kuk.

St. XvOuis.

Xvaskaskia,
Chester.

Lr. Coal Measure.

Middle and Upper
Coal Measures.

Permian.
Triassic.

230 PALEONTOLOGY OF NEW YORK.

Genus BILLINGSELLA, gen. nov.

PLATE VUa, figs. 1-9.

1857. Orthis, Billikgs. Report Geological Survey of Canada, p. 297.

1861. OrtMsina, Billings. Geology of Vermont, vol. ii, p. 949, figs. 350-352.

1861. OrtTiisina, Billings. Palaeozoic Fossils, vol. i, p. 10, figs. 11, 12.

1862. Orthisina, Billings. Palaeozoic Fossils, vol. i, p. 138, fig. 115.

1863. Orthis, Hall. Sixteenth Kept. N. Y. State Cab. Nat. Hist., p. 134, pi. vi, figs. 23-27.
1863. Orthisina, Billings. Geology of Canada, p. 284, fig. 289.

1867. Orthisina, Hall. Ti-ans. Albany Institute, vol. v, p. 113.

1882. Orthis, Whitfield. Geology of Wisconsin, vol. iv, p. 170, pi. i, figs. 4, 5.

1883. Orthis (Orthisina?), Hall. Report of State Geologist N. Y., pi. xxxvii, figs. 16-19.

1884. Orthisina, Whitfield. Bulletin Am. Museum Nat. Hist., vol. i, p. 144, pi. xiv. fig. 6.
1886. Orthisina, Walcott. Bulletin No. 30, U. S. Geol. Survey, pp. 120-122, pi. vii, figs. 5-7.

This term is proposed to include certain species, few in number, according
to present knowledge, which have some decided external resemblance to Orthis
and Clitambonites (^Orthisina), but which must be excluded from these genera
on the basis of internal characters. The form taken as typical of this genus is
Orthis Pepina, Hall, of the Potsdam sandstone of Wisconsin ; other examples are
Orthisina festinata, Billings, 0. orientalis, Whitfield, and 0. transversa, Walcott.

Diagnosis. Shell transverse ; subquadrate or semicircular in outline. Con-
tour concavo- or plano-convex. Surface sharply striate or plicate. Pedicle-
valve the more convex ; cardinal area moderately high, vertical or slightly
incurved. Delthyrium covered by a convex plate, which, in rare instances,
may be minutely perforated at the apex ; the teeth are well developed, but
the dental plates are continued along the bottom of the umbonal cavity,
enclosing a small subelliptical muscular area near the apex. In the brachial
valve the cardinal area is greatly inclined, making an obtuse angle with that
of the opposite valve. The delthyrium is partially covered by a convex
deltidium which never attains the development seen in the opposite valve, and
is often wholly absent.

Type, Orthis Pepina, Hall. Potsdam sandstone.

Observations. From the foregoing description it is evident that the
characters of this group are essentially orthoid. The shells are, however, all
small and bear in common an expression unlike that of Orthis, while the
presence of a highly developed arched deltidium is a feature showing positive

BRACHIOPODA. 231

relationship to Clitambonites, as does also the concave plate in the delthyrium
of Protorthis Like Protortiiis, this genus includes a series of primordial
species antedating both Orthis and Clitambonites, but apparently having
attained about the same stage in the line of development toward these genera.
To the species above mentioned may probably be added the Streptorhynchus?
primordiale, Whitfield * from the Calciferous beds at Port Cassin, and Orthisina
grandcRva, Billings,f from the Chazy.

In the lower beds of the Upper Silurian of the Anticosti series occurs the
Orthis? laurentina, Billings, a shell with the interior characters, and the exterior
expression of Orthis calligramma, differing only in the presence of deltidia upon
both valves, and in this respect resembling Billingsella and Clitambonites.

Genus PROTORTHIS, gen. nov.

PLATE VU A, FIGS. U-21.

1868. Orthh, Hahti'. Dawson's Aciuiian Geology, Second Edition, ji. 644, fig'. 2H:{.
1884. Orthis, Walcott. Bulletin No. 10, U. S. Geological Survey, p. 17, pi. i, figs. 1, 1 a-d.
1. 1884. Ot-this, Walcott. Monogr. U. S. Geological Survey, vol. viii, j). 22, pi. ix, tigs. 8, 8 a.
1886. Orttis, Matthew. Transactions Royal Society of Canada, Sec. IV, p. 43, pi. v, tigs. 20a-c;

(1) p. 42, pi. v, figs. 18 a-c.

There is a small group of shells passing under the name of Orthis whicli
should be separated from that genus, and given a new designation, since none
of the existing generic groups can properly receive them. Their distinctive
characters are as follows :

Diagnosis. vShells small, transversely subquadrate or semicircular. Hinge-
line straight, its length being equal to the greatest width of the valves. Valves
unequally biconvex, or sub-planoconvex, the pedicle-valve being the larger.
The cardinal area is narrow on both valves, but is higher on the pedicle-valve,
and is transected by a broad delthyrium which is closed below by a concave
plate apparently produced by the union of the dental lamellae, which are not
continued to the bottom of the valve; teeth distinctly developed. In the
brachial valve the cardinal area also bears an open delthyrium ; the dental

* Bulletin No. 8, American Museum of Natural History, p. 301, pi. xxiv, fig. 7. 1886.
t Canadian Naturalist .and Geologist, vol. iv, p. 349. 1859.

232 PALEONTOLOGY OF NEW YORK.

sockets are obscure and the crural plates small ; the latter appear to unite and
form a low elevation across the base of the delthyrium. Cardinal process
absent or rudinientary in all the specimens examined. Muscular markings in
both valves extremely obscure.

Surface marked by distinct plications, with interstitial finer radii, which are
crossed by delicate concentric striae ; these are usually accompanied by a low
sinus and fold on the brachial and pedicle-valves, respectively ; interior very
finely papillose. Shell-substance fibrous and apparently punctate.

Type, Orthis BilUngsi, Hartt. St. John group.

Mr. G. F. Matthew has kindly furnished an abundance of specimens for the
study of Orthis BiUmgsi, Hartt,* and Orthis Quacoensis, Matthew,f from his
Division I of the St. John group. These species are congeneric, and it is
possible that Mr. W.\lcott'sJ Orthis Eurekensis, from the Prospect Mountain
group, Nevada, belongs to the same genus. It has already been observed that
Billings' species, 0. Mycale and 0. Tritonia, from the Levis formation, are also
without evidence of a cardinal process ; but it is impossible to say whether
they agree with 0. BilUngsi in other respects.

The characters of the St. John species are eminently comprehensive ; first,
the form of the shell is one more frequently met with among the strophoine-
nids than among the orthids ; the concave plate formed hy the union of
the dental lamellae is never found in Orthis proper, though occurring in Scen-
IDIUM. In Orthisina or Clitambonites this plate is always present, but always
supported by a median septum and invariably accompanied by the convex del-
tidium, which, so far as known, does not exist in Protorthis ; while in the
group typified by Orthis Pepina, Hall (here designated by the term Billingsella),
the convex deltidium of Clitambonites is present and the concave or dental
plate absent. The apparent absence of a cardinal process in Protorthis may
be due to the imperfections of the fragile shells studied. The specimens of the

* Harit, Dawson's Aciuiiau Geology, Second Edition, p. 044, fig. 223. 1S68. Walcott, Bulletin No.
10, U. S. Geological Survey, p. 17, pi. i, tigs. 1, 1 ii d. 1884.

t Illustrations of the Fauna of the St. John (Ji-onji. No. ;i. 1885. Trans. Royal Soc. Canada. Si'c. IV,
p. 48, pi. V, figs. 20 a-c. 1886.

J PallEontology of the Eureka District, p. 22, [il. xi, figs. 8, 8 a. 1884.

BRACHIOPODA. 233

St. John shells are preserved as external and internal casts, and from some of
these there is reason to infer that the substance of the shell was punctate.
Mr. Matthew, in a private note, intimates that his Kutorgina Latourcnsis\ may
belong to the same group of shells. This species has been discussed in the
preceding pages, under the genus Kutorgina,:}: and although an examination of
the more complete material received from Mr. Matthew, with his identifica-
tion, has not proved entirely conclusive, there are reasons in favor of adopting
the views of this author.

Genus CLITAMBONITES, Pander. 1830.

PLATE VII, FIGS. i3-28 ; and PLATE XV A, FIGS. 1-s.

1822. Anoiiiites, Schlotheim. Nachtrage zui- Petrefactenkuude, p. 65, pi. xiv, lig. 2.

182S. Orthis (■partim), Dalman. Kungl. Sveiiska Veteiiskaps-Akail. Handl. for 1S27, p. 1 1 1, pi. ii, tig. 1.

1830. Klitamhonites, Pander. Beitrage zur Geognosie des russ. Reiche.s, p. 70, jil. iii, tig. 14;

pi. xxviii, figs. It!, 17, 23, 24 (generic figures).

1830. Pronit&s, Pander. Beiti-age zur Geognosie des russ. Reiches, pp. 71-74, pi. xxviii, tig. 16 (gen-
eric figures) ; pis. xvi, xvii, xviii, xxiii, xxiv, xxvi.

1830. Hcmiprouites, Pahder. Beitrage zur Geognosie des russ. Reiches, jip. 74-76, i)l. iii, lig. 14 ;

pi. xxviii, tig. IS (generic iigui-es) ; pis. xvIb, xviii, xxii, xxiv.

1830. GoitamhonitcK, Pander. Beitrage zur Geognosie des russ. Reiches, pp. 77-80, [il. iii, tig. 1 ;

pi. xxviii, fig. 15 (generic figuri's) ; pis. xv, xvi A, xvi b, xx, xxv.

1837. Orthis, von Buch. Abhamll. der k. Akad. Wissenscbaft. Berlin, p. 63. 1836.

1840. Ortliis, von Been. Beitrage zurBestimni. der Gebirg.'?forniation Russlands, p. 20.

1840. Orthis, von Bocu. Mem. Socii'te Geologique de France, vol. iv, pp. 208-211.

1840. Orthis, von Eichwald. Urwelt Russlands, pt. i, p. 15.

1840. Ortliis, von Eicuwald. Ueber das Silur. Schichten-Systeni von Estland, p. 14S.

1842. Ortliis, von Eichwald. Urwelt Russlands, pt. ii, p. 145, pi. iv, tig. 11.

1845. Orthis, db Verneuil. Geol. de la Russie et de Mont, de TOui-al, pp. 198-201). pi. xii. tigs. 1-4.

1846. Ciitambonites, Agassiz. Nonienclator Zoologicus ; Index Univer., p. 90.

1847. Orthisina, d'Orbigny. Coniples rendu.s vol. xxv, p. 267.

1847. Orthisina, d'Orb!gny. Ann. Science Nat., vol. viii, p. 268, [il. viii, tig. 7.

1850. Orthisina, d'Orbiuny. Ann. Science Nat., vol. xiii, p. 319.

1850. Orthisina, d'Orbigny. Prodrome de Paleonf. stratigrap.h. univ., )>. 16.

1852. Orthisina, McCoy'. Bi-itish Paleozoic Fos-sils, p. 231.

1853. Orthisina {partim), Davidson. Introd. Britisli Fossil Brachiopoda, p. 104.
1859. Orthis, von Eichwald. Lethjea Rossica, vol. i, p. 838.

1865. Orthisina, Shaler. Bulletin No. 4, Museum Comparative Zoology, p. 67.

1871. Orthisina, Davidson. British Silurian Brachiopoda, p. 278, pi. xlix, tigs. 27-29.

1878. Hnniproait.es, Whitfield. Ann. Rept. Geol. Survey of Wisconsin, for 1877, p. 72.

1882. Hemipronitts, Whitfield. Geology of Wisconsin, vol. iv, p. 243, pi. x, tigs. 15-17.

1883. Orthisina, Davidson. Briti.sh Siluri.an Brachiopoda; Snppl. p. 175, pi. xvi, tigs. 16-18.
1887. Clitamhonites, (E,Hi.v.Kr. Fi.s(;her"s Manuel de Conchyl ; Bra<'hiopoda, p. 1289.

* Illustrations of the Fauna of the St. John Group, p. 42, pi. \-, tigs. 18 a-c.
t See page 93, plate iv, tigs. 18-20.

234 PALEONTOLOGY OF NEW YORK.

Diagnosis. Shells with a subsemicirciilar marginal outline ; convex or
subpyramidal in the typical group. Hinge-line straight, and forming the
greatest diameter of the shell. Pedicle-valve elevated, cardinal area high, ver-
tical, or sometimes incurved, and crossed by a broad delthyrium, which is
normally covered by a convex, perforate deltidium. On the interior of the
valve the dental lamelloe are very strongly developed, converging and uniting
in the median line before reaching the bottom of the valve ; thus forming a
spondylium* which with the deltidium encloses a conical subrostral vault.
This plate is supported by a median septum extending for about one-half the
length of the valve. Muscular impressions obscure. In the brachial valve, the
cardinal area is considerably developed, and the delthyrium filled by a con-
spicuous callosity, against the inner side of which the simple orthoid cardinal
process abuts. The dental sockets are large, the crural plates low and continu-
ous with the edges of the delthyrial callosity. A thickened transverse area is
formed in the umbonal region by the union of the inner portions of the crural
plates with the cardinal process, and thence a broad median ridge is continued
forward through the muscular area, which is sharply defined and quadripartite.
External surface covered with radiating striae. Shell-substance impunctate.

Type, Pronites adscendens, Pander. Lower Silurian.

American example, Orthisina Verneuili, von Eichwald. Trenton limestone.

Observations. Although d'Orbigny's term, Orthisina, has found its way
into general use for this group of shells, there is no reason why it should replace
the name Clitambonites, a genus clearly defined and abundantly illustrated by
its author. In order to show Pander's conception of this group, and since his
" Beitrage zur Geognosie des russischen Reiches " is a work not generally ac-
cessible to American students, his original descriptions and typical figures are
here introduced.!

* liTlovdvXlov , vertebra. This teiin will apply with equal propriety to the similar plate existing in the
l)edicle-valvfi of other brachiopods, e. g., Clitambonites, Pentamkrus. Camarella, Stenoschisma, etc.

t Pander's deterrainations of g-enei'a and species of brachiopoda evince a remarkable insight and ana-
lytical power. He was in this i-egard a generation in advance of his contemporaries, who apparently felt it
their duty to thi-ow both his g-enera and species back into the old groups whence they were derived, and
thus totally ignore his work. The inaccessibility of Pander's works to westc-rn students, has been one great
r'ause of the niisnnderstanding of many brachiopodons genera.

BRACHIOPODA. 235

" Klitambonites. Die Schlossflache der oberen Schale bildet ein vollkom-
menes Droieek, dessen Grimdlliiclie an der Beriihnmg.sstelle derselben init der
unteren Schale sich befindet, und dessen Spitze schnig oder gerade nach oben
gegen die Oberfiiiche hinaufsteigt. hi dor Mitte dieses grosseren Dreiecks findet
sich noch ein kleineres, das gewcilbt nach aussen hervortritt und das wir, in so
fern es von aussen die zuni Schlosse gehr.rigen Theile beschiitzt, niit dem
Namen des Schlossdeckels belegen woUen. Die Schlossflache der unteren Schale
ist fast geradlinig, ragt etwas nach aussen hervor und liildet in der Mitte einen
Wulst, zwischen welcheni und deni Schlossdeckel die bald sicheltVirmiire. bald
dreieckige Oeffnung zum Durchgange des fleischigen Stieles sich befindet. Die
vier Seiten der Schalen sind hier am deutlichsten ausgesprochen, die Obertliichen
sind wenig gewolbt, gewOhnlich verlauft die der oberen Schale von der Spitze
der Schlossflache, welche hiiufig den hochsten Punkt bildet, schrag nach vorn
und gegen die Seiten sich abfliichend fort. Der Queerdurclnnesser ist gewohn-
lich der vorwaltende.

" Die feinen Langsrippen werden durch concentrische, unter einander und
niit der Brust und der Seitenlinien parallel laufende, Strcifen unterbrochen, so
dass erstere treppenartig, selbst etwas dachziegelartig auf einander zu liegen
kommen. Die Brustlinie ist in der Queere im Allgemeinen gerade, seiten und
audi dann nur unbedeutend gegen die Oberschale sich hinaufbeugend. Da aber
hier doch sehr grosse Verschiedenheiten sowohl in Riicksicht der Wolbung,
als der Durchmesser und der Hfihe der Schlossflache vorkoininen, so wird es
bequemer sein, die Klitamboniten noch in zwei Abtheilungen zu trennen,
welche sich hauptsiichlich dadurch unterscheiden, dass bei den einen, die wir
Proniten neiinen, die obere Spitze des Dreiecks der SchlossHiiche den hiichsten
Pnnkt in der Schale erreicht, w;dirend bei den Heiniproniten letztere zwischen
der Riickenflache und der Brustlinie fiillt, erstere also niedriger ist."*

-^:s^

I'runites atlsccndc-ns. After Tandek.

* "The cardinal area of the upper valve forms a, complete triang-le, whose base is tli« line of junction of
the valves and whose apex is either inclined or direct. In the center of this larf,'e trjangle is a smallei- one,
which is arched outward, and inasmuch as this pi'oteets the parts behmg-ing- to thi^ hinf,'e, we shall term it
the Hinge-cover. The cai-dinal area of the lower valve is almost sti'aight and somewhat elevated and out-
wardly iru'lined ; in the center is a swelling-, bcrtween which and the hinge-cover is the sometimes sickle-

236

PALEONTOLOGY OF NEW YORK.

It was evidently the intention of the author to make not only these two
divisions Pronites and Hemipronites of the genus Klitambonites, but also to
include as of coequal value the divisions Gonambonites, Orthambonites and
Plectambonites ; and the principal differences in these divisions, as based on
the varying inclination of the cardinal area, are expressed in the following
figures taken from Plate 28 of his work.

a

4. rt, Cl.lTA.MHDNETKS; 6, GONAMBONITES; C, CLITAJIBONITES; d, OUTHAMIiONITES; «, PLECTAMBONITES.

After Pander.

Orthambonites is undoubtedly precisely synonymous with Orthis, Dalinan.
Plectambonites is manifestly a good genus, equivalent to Lept^ena of authors,
not of Dalman. Dall has called attention* to the fact that Pander, in sub-
dividing the entire group of Clitambonites, left no type-species upon which the

shaped, sometimes ti-iang'ular opening for the passage of the fleshy pedicle. The four sides of the shells
are most clearly pronounced ; the surfaces are slightly arched, that of the upper valve usually slojiing from
the apex of tlie (-ardinal area, which is generally the highest point, ratlier alii'uptly forward, and more gently
toward the sides. Tlie transverse diameter is usually the greatest.

"The fine longitudinal rilis are interrupted by concentric lines, parallel to one anothei- and to the ante-
rior and lateral margins ; thus tlic former lie on one another like steps or roof-tiles. The anterior margin
is, in general, straight, rarely, and then but inconsiderably, liending toward the upper valves. As, however,
there are gi'eat differences both in c<invexity and in the diameter and height of the cardinal area, it will
be more convenient to separate the Klitaud)onites into two divisions, which are distinguished principally by
the fact that ill one, which we tiM'iii I'ronites, the upper angle of the triangular cardinal area reaches the
highest point in the sh'ell, while in the Hemipronites, the last lies between the posterior and anterior mar-
gins, and the cardinal area is therefore lower."

* Bulletin No. S, U. S. National Museum, p. :!9. 1877.

BRACHIOPODA. 237

application of this term can l)e leased. It is therefore necessary to take the
first species of the typical subgenus Pronites* (Pronites adscendens) as the type
of Clitambonites; and it will probably prove desirable to limit the application
of this term pretty nearly to the typical division included by Pandkr under

FiG.s. 5, 6. Orthrnnhnnitpn trfjnsi'er.ta. After Pandkk.

Pronites; that is, to shells having the lower valve flat, the upper valve with
the greatest elevation at the beak, the greatest width of the shell along the
hinge, and the cardinal area vertical. It will probably be unwise to attempt
to maintain the term Gonambonites for forms similar in all respects to Clitam-
bonites except in having a backward inclination of the cardinal area.

With the foregoing definition of Clitambonites, d'Orbigny's Ortiiisina is ap-
parently a synonym The name was proposed in the Comptes Rendus, in 1847, but
no example was cited. It was again used in the same year in the Annales des Sci-
ences Natur elks, and accompanied by a figure without specific name. In 1850 it
was used in a later volume of the same work, without the specification of a type,

Figs. 7, S. Gowtmhonites lata. Alter Pander.

but with mention of three species: (1) 0. ammala, Schlotheim; (2) 0. adscendens,
Pander; (3) 0. Verneuili, von Eichwald; and in the same year the name is again
defined in his Prodrome de Paliontologie Stratigraphique, etc., with tlie species cited
in the following order: (1) 0. Verneuili, (2) 0. anomala, (3) 0. adscendens. 0.
Verneuili, if taken as the type of this group, presents a species in all generic
features identical with Clitamhoniies adscendens. Should, however, 0. anomala be
regarded as the typical species of Orthisina, it may eventually be desirable to

* It .appears that Promtk.s was also a pi-eoixiiiiieil term, litiviiij^ lieen useil by Ilmgbr for a {jeiiua of
birtls, ill ISII.

238 PALAEONTOLOGY OF NEW YORK.

accord the term a subordinate value oil the basis of the extravagantly devel-
oped cardinal area in the brachial valve. (See Plate VII, figs. 25, 26.)

Hemipronites. The type of structure exemplified by this group is distinct
in many important respects from that of Pronites {Clitambonites) adscendem. The
valves are subequally convex, the hinge-line shorter than the greatest diame-
ter of the shell, the greatest depth of the pedicle-valve is not at the apex ;
the deltidium is apparently not perforated, and the surface is covered by ex-
tremely fine radiating striae. Regarding Hemi-
pronites tumida as the type, the association of
species will represent a very well defined group,

, 111 c 1 T Figs. 9, ]0. ncmipronitcs tnmMa

which may provisionally be held as or subordi- Aftei pauuee.

nate vakie to Clitambonites, but which when better known may have to be
more definitely separated from that genus. Its interior characters, other than
the dental trough supported by a median septum, are not well understood.*

The features of Clitambonites are very strongly orthoid. This is seen to
best advantage in the brachial valve, where the difference from' the interior of
O. calligramma rests principally on the modifications produced by the delti-
dium. The Orthis ? laurentina of Billings, from the Anticosti group, or Mid-
dle Silurian, is in every respect an intermediate form between Orthis calli-
gramma and Clitambonites. In Billingsella the dental plates do not unite,
though the delthyrium is completely covered in the pedicle-valve and partially
so in the brachial valve. The earliest appearance of these features is in the
primordial species of Protorthis and Billingsella, the former genus being, so
far as known, without a convex deltidium but having the concave dental trough
or spondylium developed, though unsupported by a median septum. In the
genus Polytcechia is the earliest known combination of these two features,

* It is evident that PaiNueu (li<l not regard tliLs tii'st species in bis list as a tliorougbly normal example
of the group. He says (p. 74) : "Schon durch Pr. ohlnnga und humilis sahen wir, dass ein Uebergang zu
den Hemiproniten Statt fand, ein andei-er geschieht durch Hemipronites Uimida, bei welchem die RUcken-
flache noch zieinlicli hocli liitiaufi'agt, allein nieht raehr die hochste Spitze der Obei-scbale bildet, letztere
wolbt sich scbon vollkommen, und der aussere Ansehen ist doch noeh das einesProniten." Probably a more
typical example of bis twenty-one species would be ff. alta, pi. xxiii, fig. 6, or H. sphmrica, fig. 7.
Ue Veh.neuil, in the Geologic de la Russie, etc., \t. 20.5, referred nineteen of tbe.se species to the OrtMslicml-
pnmites of von Bueii, 1840, a name which of course has no value if founded on any of Pander's species.

BRACHIOPODA.

239

and the formation of an umbonal or subrostral vault supported by a median
septum.

The geological range of both Clitambonites and Hkmu'ronites is limited to
the Lower Silurian. In American faunas the latter group is still unknown,
and the former is represented by only two species, Orthisina Verneuili (von Eicli-
wald), Billings, from the Trenton limestone and the Anticosti fauna, and
Hemipronifes Americana, Whitfield, a closely allied species, from the Galena
horizon of the Trenton, in Wisconsin.

PoLYT(ECHiA, sub-gen. nov.

Plate vii a, figs. 26-30.

1886. HfiiiipfDiiiUs. Whitfii-:i.i>. liulletiii Ainei'icau Miiseiiin of N.-itiiral History, vol. i. No. S. ji. HOO.

pi. xxiv. tijr-'^. !-.').

This name is proposed for the species Hemipronites apicalis, Whitfield, the
essential characters of which have been clearly demonstrated by that author. *
Mr. Whitfield recognized the distinctive character of this fossil but hesitated
to propose a new generic term, which circumstances now require.

Fig, 11. Polytachia apicalis.
Transverse section of ptMiicIevalvc, m-ar tlur apt'X.

Frn. 12. rolytachia apicalin
Trausvei'se section near tlie canltnal mar^rin.

Diagnosis. Shell small, subtrihedral in contour. Hinge-line straight, about
equaling the diameter of the shell. Pedicle- valve witli a high, nearly verti-
cal cardinal area marked with oblique striations parallel to the lateral margins.

* 111 a provisional list of tlie genera of jiahiiozoic biacliiopoiia, pulilishetl in the Eighth Annual Report
of the State Geologist (p. 44, 1889), the name Waaoenia was used with the intention of applying it to this
sub-genus, but it appears that both Waagenia an<I Waaoeneli.a are preoccupied terras, therefore iireclud-
ing this intended expression of e.steein and appreciation for the invaluable service.-^ of Dr. Waahk.n in this
department of science.

240 PALAEONTOLOGY OF NEW YORK.

Delthyrium covered by a narrow, convex plate ; tlie presence of a foramen not
determined. On the interior the dental lamelliB are widely separated, and
descend along the umbonal cavity for a short distance vertically, thence
Ijending sharply inward and meeting at a low angle in the median line ; thus
forming, with the deltidium, a conspicuous subrostral vault. This inner spoon-
shaped plate, spondylium, is supported by a stout median septum, and two
smaller lateral septa, which meet it at the lines of angulation ; the former of
these extends for the entire length of the plate, while the latter is free from
the accessory septa near its anterior edge. The umbonal cavity of the valve
is thus divided into five chambers, and in the lateral chambers there is still
another septum, lower than the rest and not extending to the spondylium.
The brachial valve is shallow and depressed-convex, with a narrow cardinal
area. The delthyrium is very broad with a partially developed covering, the
dental sockets are widely separated, the crural plates narrow and nearly paral-
lel to the hinge-line The cardinal process is simple, linear and quite promi-
nent, and at its union with the crural plates is a subtriangular thickening
which is supported by a low median septum. Surface covered with fine,
elevated, radiating striae, without evidence of median fold and sinus.

Type, Hemipronites apicalis, Whitfield (not Orthis ? apicalis, Billings). Calcif-
erous beds.

The closest relations of this sub-genus are with Clitambonites (= Orthisina),
being chiefly distinguished by the multipartite umbonal cavity of the pedicle-
valve. The typical species is from the fauna of the Calciferous sandstone of
Fort Cassin, Vermont. With this species Mr. Whitfield compares the Orthis ?
apicalis of Billings, from the "Quebec group" (Point LiWis Limestone, No. 1),*
but after examining the original specimens of both species, and with consider-
able additional material from Fort Cassin, there can be no hesitation in pro-
nouncing the two forms as quite distinct, not only in internal structure, but
also in external characters.

* PaUeozoic Fossils, p. 'Mil, i\'^. 21tl a.

BRACHIOPODA. 241

Genus SCENIDIUM,* Hall. 1860.

PLATE VU A, FIGS. 31-43.

1846. Orlhis, Rouaclt. Bulletin Soc. Geologique de Prance, '2iul Ser., tome iv, p. 322.

1848. (h-this, Davidson. Bulletin Soc. Geologique ile France, 2ii(l Sei-., tome v, p. S23.

1852. Orthis, Hall. PaK-eontology of N. Y., vol. ii, p. 251, pi. li, tig. 2.

1853. Orthis, Schnur. Zusammenst. und Beschieib. Eifel Bracliiopoiien.
1859. Oi-ihli, Salter. Murchison's Siluria, p. 544.

1859. Orthis, Hall. Paleontology of N. Y., vol. iii, p. 173.

1860. Orthis, Lindstrom. Gotland's Brachiopodei-, p. 370.

1860. Skenidium, Hall. Thirteenth Rept. N. Y. State Cat). Nat. Hist., p. 70, tigs. 1-5.

1861. Skenidium {Ortliis), Hall. Palasontology of N. Y., vol. iii. pi. x a, tigs. 13-15.

1868. Orthis, Davidso.n. Trans. Geological Society of Glasgow.

1869. Skenidium, Safford. Geology of Tennessee, p. 287.

1869. Orthis, Davidson. British Silurian Biachiopoda, p. 208, pi. xxv, tigs. 4, 9.

1871. Orthis, Davidson. British Silurian Brachiopotla, p. 254. pi. xxxviii, tig. 20.

1871. Orthis, QcENSTEDT. Petrefactenkuude Deutschlands.

1871. Mystrophora, Kaysbr. Zeitschr. der deiitsch. geolog. Gesellschaft, j). 612, i)l. xiii, tig. 5.

1872. Orthis, Rigaux. Bulletin Society Academ. de Boulogne.

1882. Skenidium, Davidson. British Devonian Brachiopoda. Suppl., p. 49, pi. iii, tigs. 11-14.

1883. Skenidium, Davidson. British .Silurian Brachiopoda. .Sujipl., pp. 173-175, pi. xi, figs. 1-7.
1883. Skenidium. Hall. Report of N. Y. State Geologist for 1882, pi. xxxvii, tigs. 29-35.

(1) 1884. Skenidium. Waloott. Paleontology of Eureka District, p. 116, pi. xiii, tig. 4.

1887. Sceiiidium. QEhlbrt. Bull. Socit'le d'Etudes Scientiticjues d'Angers, extr., p. 4, pi. v, tigs. 8-10.
1887. Skenidium, Tschernyschew. Meinoires Comite Geologiipie, vol. iii, No. 3, pji. 10(), 107, pi. iv,

figs. 13-17.

Diagnosis. " Shell subpyramidal, somewhat semicircular, with or without
median sinus and elevation. Area large, triangular, divided by a narrow
fissure, which is sometimes closed at the summit by a concave deltidium.
Valves articulating by teeth and sockets, which are often obscure or obsolete.
Dorsal valve Hat, or varying from depressed-convex to concave. Beak entire,
or indented by the foramen ; cardinal line straight and usually equaling the
width of the shell ; cardinal plates broad and well developed, marked by the
imprints of the peduncular muscles, and produced in the middle in a pointed
process ; the cardinal process extends, as a median septum, through the length
of the shell, and may be simple or divided at its [anterior] extremity. Ventral
valve elevated, subpyramidal; beak straight or slightly arched ; muscular im-
pressions undetermined. Exterior surftice covered with radiating strias." —
Hall, 1860, ut. cit.

Type, Orthis imignis. Hall. Lower Helderberg group.

* The customary spelling of this generic term has beea Skenjdidm ; the better form is undoubtedly
ScBNiDiOM, as suggested by Dr. (Ehlert.

242 PALAEONTOLOGY OF NEW YORK.

Observations. The shells of this genus are all small, ami the high, usually
erect cardinal areas give them a distinct cyrtiniform aspect. Their essential
characters are, however, very positively orthoid. In the typical forms of
Orthis following the structure of 0. calligramma, there is, first the pyramidal
form of the shell, less pronounced indeed than in Scenidium ; then, on the
interior of the brachial valve, a general thickening and elevation of the delti-
dial region as illustrated in Plate V, fig. 14. This thickening ends abruptly
below the crural plates, and at the base of the narrow, simple, cardinal process,
but a low median ridge is continued forward until it is merged into the radial
plications of the shell. In the species described by Mr. Billings as 0. Merope,
from the Trenton limestone,* and a very closely allied, probably identical
form from the Hudson River horizon at Cincinnati (in both of which the
size and form is that of Scenidium), the interior features of the brachial valve
are precisely of this character, and the shell evinces no progress from Orthis
toward Scenidium except in its interior. A pronounced advance in these
respects is seen in Scenidium Halli, Saftbrd, from the Trenton horizon of
Minnesota and Tennessee ; here the deltidial area is more distinctly elevated
and the median septum low, but sharply defined. In Scenidium pyramidale, Hall,
of the Niagara, an abundant shell at Lockport, N. Y., and S. Lewisi, Davidson,
of the Wenlock of England and Gotland, the septum of the brachial valve is
higher, though not attaining so great a development as in the Lower Helder-
berg species, S. insigne, where it extends for a considerable distance into the
cavity of the pedicle-valve, virtually dividing it into two chambers.

The extreme development of these characters is attained in Scenidium areola,
Quenstedt (sp.), from the middle Devonian of the Eifelf and Torquay.:]: Here
the cardinal platform is wholly separated from the bottom of the valve, and is
supported l)y the median septum, the latter being a high vertical partition
extending to the opposite valve and leaving only its subrostral cavity
undivided.

* Palaeozoic Fossils, vol. i, p. 139. 1862.

t Kaysbh. Zeitschr. der deutsch. Geol. Gesellschaft, vol. 23. ]k (512. pi. xiii. liir. fi. 1S7].

t Davidson, British Devoiiiiui Hi-.ii;liio)inda. Siipi)!.. p. 49. 1.SS2.

BRACHIOPODA. "243

The gradual development of the characters of Scenidium can be traced from
the typical features of Orthis, and, after attaining its extreme manifestation in
the Devonian, this combination abruptly disappeared, and no further repre-
sentatives in this line have been discovered.

The incurved plate in the rostrum of the pedicle-valve, which in the orig-
inal diagnosis was regarded as a deltidium, appears to be due to the union of
the dental lamellae, forming a spondylium analogous to that in Clitambonites.

The shell-substance of Scenidium is very finely fibrous, and from sections of
S. pyramidale appears to be impunctate. Mr. Davidson, however, has repre-
sented* an enlargement of the surface of S. areola, which shows superficial
granulations or pits which may be evidence of punctate structure. Accord-
ing to present knowledge Scenidium appeared in the fauna of the Trenton
group, and has had a wide distribution, disappearing in the Devonian.

Besides the American species already mentioned, Mr. Walcott has described
S. devonicum, from the Lower Devonian horizon of the Eureka District, Nevada.
Scenidium Lewisi, Davidson, occurs in the Wenlock of England, Scotland and
the Isle of Gotland; S. Lewisi, var. Woodlandense, Davidson, in the Middle
Llandovery of Ayrshire ; S. Lewisi, var. Hughesi, Davidson, in the Coniston
grits; S. Shallockense, Davidson, and >S'. Grai/im, Davidson, in the Middle
Caradoc of Girvan.f Mr. Davidson has also referred to this genus the Orthis
Deshayesi, Bouchard, occurring in the Devonian beds of Ferques, Brittany ;:|:
and ffiHLERT describes Scenidiu?n Baylii (= Orthis Baylii, llouault), from the
Devonian of Gahard, in the west of France. § Two other Devonian species
have been described by Tschernyschew,|| from the Stringocephalus-beds of the
Urals, viz., S. Malleri and S. Uralicum.

* British Devonian Brachiopoda. Siippl., p!. iii, fig-. 11 (!.
t See Davidson, British Silui-ian Urai'hiopi.rla. Suppl., i)p. 173-175. 188:?.

J See Davidson, British Devonian Bracliiopoda. Suppl., p. ,")0. 1884 ; ami RKiAUX, Bull, ile la Societe
Academique de Boulogne, vol, i. 1872.

§ Brachiopodes du Devonien de roue.st de la France, p. 4. 1.SS7.

I Die Fauna des mittlereii und obereii Devon am West-Abhanjje lies Urals, pp. lOtJ, 1U7.

244 PALAEONTOLOGY OF NEW YORK.

Genus ORTHIDIUM, gen. nov.

PLATE VII A, FIGS. '-'i-'o.
1862. OrtMs, Billinos. Palaeozoic Fossils, vol. i, p. 75, tiir.';. 8, a, b, c.

Diagnosis. Shell very small, transverse, having the external aspect of
ScENiDi0M. Hinge-line long, making the greatest diameter of the shell. Ped-
icle-valve the more convex ; cardinal area moderately high, with a broad open
delthyrium, strong teeth and inconspicuous dental plates, in all respects like
the corresponding valve of Orthis calligranima. Brachial valve slightly con-
vex ; cardinal area very narrow ; dental sockets well developed, crural plates
very short and erect, coalesced with the cardinal process, which thus becomes
a vertical, transverse, .subcrescentic plate, at the base of which the shell is
somewhat excavated ; muscular scar quadruplicate. Surface covered with
radiating striae, which extend over the broad, low sinus and fold in the brachial
and pedicle-valves respectively. In the former the sinus makes a prominent
median ridge in the interior of the valve. Shell-structure not determined.

Type, Orthis gemmicula, Billings. Quebec group.

Observations. This interesting fossil presents the earliest known phase of
the development of the cardinal process which characterizes Strophomena, and
the other streptorhynchoid genera ; and it is upon this feature that its
separation as a distinct genus is rendered necessary. All the features of the
pedicle-valve are strictly orthoid.

On the brachial valve the cardinal process instead of being bipartite at its
crest, and grooved or multipartite on its posterior face, is simple, terminating
in a rounded apex and filling the delthyrium.

These features are beautifully shown in Mr. Billings' original specimens of
Orthis gemmicula, which have been kindly loaned by the Director of the Geo-
logical Survey of Canada, thi-ough Mr. J. F Whiteaves, for the purpose of
illustration in this volume. No other species referable to the same genus is at
present known. Orthis gemmicula is from the Quebec group, at Point Levis,
" in the upper part of Limestone No. 2" (Billings).

BRACHIOPODA. 245

Genus STROPHOMENA, Rafinesque (de Blainville). 1825.

PLATE IX, FIGS. l-'20; PLATE LX A FIGS. 3, 5-18; and PLATE XI A. FIGS. 1-S.

1820. Strophomenes, Kakixesque. Annales Gen. Sci. phys. BiuxoUes, totn. v, j>. 262.

1824. Strophomenes, Deprance. Tableau des Corps oi-ganises fossiles, p. (i.

1825. Stropkomeua, dk Blainville. Manuel de Malacolog-ie et Conchyliologie, vol. i, p. SIS, pi. liii,

Hgs. 2, 2a.

1827. Strophomenes, Defrance. Dictionnaire des Sciences Naturelles, vol. li, p. 151, and Atlas.

1831. Strophomenes, Rafinesqce. Descr. Remarkable Objects in Cabinet of Prof. Rafine,sqi;k, ]i. 4.

1839. Orthis. J. de C. Sowerby. Murchison's Silurian System, pi. xiii, tig-. 13 ; pi. xx, fig-. 18.

1844. Strophomeaa, Owen. Geological Expl. of Iowa, Wisconsin, and Illinois, p. 70. pi. 17, tig. 2.

1847. LeptCBna,, Hall. Palaeontology N. Y., vol. i, pp. 111-115, pi. xxxi B, figs. 3, 4, 7, 9.

1847. LeptcBtm, Davidson. London Geological Jounial, vol. i, p. 59. pi. xii, tigs. 22-24.

1847. Orthis, Davidson. London Geological Journal, vol. i, p. 62, pi. xiii, tigs. 14, 15, 25.

1848. LepfCBua, David.son. Bull. Societe G^ologique France, Ser. 2, vol. v, p. 319, pi. ii, tig. 11.
1848. Stroptwmeita, d'Obbignt. Bull. Societe Geologique France, Ser. 2, vol. v, p. 336.

1848. Leptmia, db Vbrneuil. Bull. Societe Geologique Fiance, Ser. 2, vol. v, p. 350.

1848. LeptOBna, Phillips and Salter. Mem. Geol. Survey of Great Britain, p. 283.

1850. StropJiomena, King. Monogr. Permian Fossils of England, p. 103.

1852. Orthis, McCoy. Synopsis Silurian Fossils Ireland, p. 31.

1852. LepiW'ia (Strophomeno), McCoy. Biitish Palfeozoic Fossils, jip. 241, 244.

1855. Strophomena, Emmons. American Geology, vol. i, p. 199, tig. 61.

1856. Strophomena, Billings. Canadian Naturalist and Geologist, vol. i, p. 203, tigs. 1, 2.
1859. Strophomena, Salter Murchison's Siluria, Third Edition, pi. xx, tig. 18.

1859. Leptwna, von Eichwald. Lethaea rossica, vol. i, p. 864.

1859. Strophomew, Hall. Twelfth Rept. N, Y. State Cab. Nat. Hist., p. 70.

1860. Strophomena, Lindstrom. Ofvei-s. af Kong. Vetenskaps-Akad. Forhandl., vol. xvii, p. 372.
1860. Strophomena, Billings. Canadian Naturalist and Geologist, vol. v, pp. 57, 60, tigs. 6, 7.

1862. StroiJhomeiM, BihUKGi,. Palfeozoic Fossils, vol. i, pp. 123-127. figs. 102-104: pii. 129, 132,

figs. 107, 109.

1862. Strophomena. Hall. Annual Report Geological Survey of Wisconsin, p. 54, tig. 7.

1863. Strophomena, Billings. Geology of Canada ; Report of Progress, p. 164, tigs. 142, 143 ; p. 209,

figs. 206, 207.
1868. Strophomena, Davidson. Trans. Geol. Soc. Glasgow, Pal. Ser., vol. i, p. 17, pi. ii. tigs. 21-23.
1871. Strophomena, James. Catalogue Lower Silurian Foss. Cincinnati group, p. 9.
1871. Orthis, Qdenstbdt. Petrefactenk. Deutschlands ; Bi-achiopoden, pp. 575, 576, pi. 56, tigs. 27-33.
1871. Strophotnena, Davidson. British Silurian Brachiopoda, p. 299, i)l. xliv, figs. 2-13, 21, 22 ; p. 311,

pi. xlvi, figs. 1-3, 5, 6.

1873. Hemipronites {Strophmnena), Meek. Palaeontology of Ohio, vol. i, pp. 77-88, pi. v, tigs. 4, 5 j

pi. vi, figs. 1-5.

1874. Streptm-hynchus, Miller. Cincinnati Quarterly Journal of Science, vol. i, p. 148, tigs. 14-16.

1874. Str&ptorhynchiis, James. Cincinnati Quarterly Journal of Science, vol. i, pi). 240, 241.

1875. Hemipi-onites, Miller. Cincinnati QuarterlyJournal of Science, vol. ii, pp. 41-49, tig. 5 and p. 50.
1875. Strophomena, Hall and Whitfield. Palaeontology of Ohio, vol. ii, p. 115, pi. v, fig. 10.

1875. Strophomena, White. Geographical and Geological Exploration West 100th Meridian, p. 69,

pi. iv, fig. 8.

1880. Streptorhynchns, Whitfield. Annual Report Geological Survey of Wisconsin, p. 61.

1881. Streptortiynchiis, James. The Palaeontologist, No. 5, pp. 41, 43.

1881. Strophomena, White. Tenth Rept. Indiana State Geologist, p. 115, pl.^ii, tigs. 13, 14.

246 PALEONTOLOGY OF NEW YORK.

1552. StreptorhiinchtW!. Whitfield. Geology of Wisconsin, vol. iv, p. 2(51, pi. xii, figp. 9, 10; p. 2t53,

pi. xii, fig.?. 11-13.

1883. Stroplunnena, David.son. British Silnvian Bi'arhiopoda, Sn])plement, p. 192, pi. xi, tigs. 20, 21 :

pi. xii, fig. 30 ; pi. xvi, fig. S.

1553. f^trcpUrrhynchtis, Hall. S<'C.ond Ann. Rept. State Geologist N. Y., Expl., pi. xxxix. figs. 1-9,

15-30 ; 111. xlii, figs. 10-15.

1884. fStreptorhynehus, Walcott. Palseontology Eureka District, ]). 75, pi. xi, fig. 9.
1887. iStrophmnena, Shaler. Memoii-s Kentucky Geological Survey, p. 13, plates 4 and 5.

Probably no generic term among the brachiopoda has given rise to a greater
diversity of expression of opinion among authors as to its value and applica-
tion. In order to appreciate the inapplicability of the term as now current
among the American and European writers, a brief risumi- of its history be-
comes necessary.

In 1820, C. S. Rafinesque made u.se of the term Strophomenes in the Annales
Generales des Sciences Physiques de Bruxelles, vol. v, p. 232.* This name was
not accompanied either by a diagnosis or the citation of any .species. The
author, after speaking of the difficulties experienced in working out certain
groups, says :

" Par exemple, parmi les tt'ivbratules, nous en avons observe'- plus de 60
esprces, que nous avons dii ranger sous plusieurs nouveaux genres, tels que
gonotrema, dictionia, didisma, pleurinia, stropheria, strophomenes, dipsilis, etc., outre
les vrais genres terehratula et produdus. Le seul G. gonotrema, qui comprend
les teri'bratules a ouvcrture anguleuse ailongee et Ji charnirre tronquee, etc.,
contient plus de 30 espi'ces."

The term Strophomenes, Rafinesque, was afterwards u.sed by Defrance, in
1824, also without definition, in the "Tableau des Corps Organises Fossiles,"
p. 6. In 1825, DE BLAiNVii.LEf made use of the term Strophomena, in the fol-
lowing manner :

" Strophomene. Strophomrna. — Animal tout-a-fait inconnu. Coquille regu-
liere symetrique, (•quilaterale, subrquivalve; une valve plate et I'autre un peu
excavee ; articulation droite, transverse, oflfrant a droit et a gauche d'une

* This paper does not appear in the "Complete Writings of Constantine Smaltz Rafinesque on Recent
and Fos.sil Conchology," edited by William G. Binnkv and George W. Tryon, Jr. 1864. As the original
paper hiU'j not been accessible, we .are under obligations to Di-. H. A. Pilsby, of the Conchological Section
of the Philadelphia Academy of Natural Science, for communicating the quotation given.

t Manuel d(! Malacologie et Coni-.hyliolngie, vol. i, p. 513. jii. liii, tigs. 2, 2a.

BRACHIOPODA. 247

subt'-cliancrure mediane, un bourrelet peu considerable, ciV-nelt- on dentek-
transversalement ; aucun indice de support.

"Ex. La Strophom/ve rugueuse, Strophnmena rugosa, Kafin., pi. liii, fig. 2.

" Observ. Ce genre, propose par M. Rafinesque, ne contient encore que dcs
especes fossiles, au noinbre de trois, suivant M. Defrance."

Figs. 13,14. StnilthnmiiK rii'i<}!«t At'ti/r Dlo lil.AI.WIl.l.E.

Tlie original figures accompanying this description are here reproduced. A
similar description of the genus, with a more extended notice of the species .S'.
rugosa, was given in 1827, in the " Dictionnaire des Sciences Naturelles," vol. li,
p. 151.* In this place the form of the generic term is invariably Strophomenes,
and the description is in the following language :

" Strophomene rugueuse ; Strophomenes rugosa, Rafinesque. Coquille bombre
en dessous, et dont la valve supi'^rieure est un peu concave et chargee de petites
stries ra3'onnantes. Largeur, un pouce. Fossile de I'AnK'rique septentrionale.
On voit une figure d'une coquille de cette espece dans I'atlasde ce Dictionnaire,
j)lanche des fossiles. Des coquilles de ce genre, qu'on trouve a Dudley en Angle-
terre, ont de tres-grands rapports avec cette espece; elles en different pourtant
en ce que le bord ce celles d'AnK'rique se retrousse un peu en dessous, tandis
que c'est le contraire pour celles d'Angleterre, dont le bord s'abaisse en dessous.
On trouve a 1' embouchure de la riviere des AUeghanys pres de Pittsborough
(Amrrique septentrionale), dans un gri-s rougeatre, des empreintes de coquilles
qui ont beaucoup de rapports avec cette espece, mais que sont plus aplaties."

We have here a good description of this American species accompanied by
intelligible figures, and although the name has never been current among
naturalists in this country, there seems sufficient reason to believe that it is the
same species which was subsequently described as Leptczna pIanumbona,j- a com-

* "Paf iilusieurs Pi-ofesseui-s dii .Jardiii da Roi, et des princiiiales Ecoles de Pai-is." The .article
" Strophomene " is sig'iied with the initials '• D. F." ; Disfranck, not dk Ulainville as nsn.ally ((noted.

t Paheontolog-y of New Yoi-k, vol. i, ji. 11-. 1847.

248 PALEONTOLOGY OF NEW YORK.

mon fossil in the upper horizon of the Hudson River group in the Ohio valley.
Rafinesque himself, did not define his genus Strophomenes in any American
worlv until the publication of his tract of October, 1831,* where it appears in
the following terms :

" Strophomenes, Raf Equilateral, hinge broad, great valve notched by a
lunulate sinus receiving a lunulate projection from the smaller valve."

In a tract published in Philadelphia in November, 1831, entitled, "Enumera-
tion and Account of some remarkable Natural Objects in the Cabinet of Prof.
Rafinesque in Philadelphia," p. 4,f the descriptions of the following species
under Strophomenes are given :

"Strophomenes, Raf, 1820. See tract of October [1831]. 1. Str. levigata. Very
smooth, longer valve convex, lower valve concave, corners acute, not auricu-
lated ; contour arched and even. Length, 4-5 of the breadth. Kentucky
limestone. 2. Sir. flexilis. Very thin, lower valve hardly concave, with minute
curved strias ; upper valve convex, with minute fiexuose strias, corners acute
subauriculate. Length and breadth equal. Limestone of Ohio, 1 or 2 inches."

In the absence of illustrations the descriptions of these species are too mea-
ger to allow of their identification. So far as known the name Strophomenes
does not again occur in the writings of M. Rafinesque, and since these species
have not subsequently been recognized or farther defined, the term Strophom-
enes, Rafinesque, in this connection can not be retained.

In 1846, King J considered S. rugosa as congeneric with Leptccna alternata,
Conrad. Sharpe,§ in 1848, takes Orthis umbraculum, Schlotheim, as the typical
species of Strophomena, including the O. crenistria, of Phillips, thus making

* The title of this tract is as follows : " Continuation of a Monograph of the Bivalve Shells of the River
Ohio, and other Rivers of the Western States. By Prof C. S. Rafinesque. (PiMished at Brussels, Sf^j-
tembei; 1820.) Containin"^ 46 species, from No. 76 to No. 121. Including an Ajipendix on some Bivalve Shells
of the Rivers of Hindostan, with a Supplement]! on the Fossil Shells of the Western States, and the Tulosites,
a new genus of fossils. Philadelphia, October, 1831."

t Binney and Tryon's Rex'rint, p. G9.

I Annals of Natural History, vol. xviii, p. 36.

§ Quarterly Journal Geological Society, vol. iv, p. 78.

II In this tract he refers to the Monograph which he had sent to Brussels for publication in the "Journal de Physique," and
writes : " I propose to give an epitome of this Monograph wiiich I have not seen in i)rint. I possess nearly all the shells."
Then follows a list of the genera which he had there propo.sed under the order Br.\chioi'H ; numbering altogether
twenty-three generic terms.

BRACHIOPODA. 249

the genus equivalent to Orthothetes, of Fischer de Waldueim, 1837, as now
defined.

In his "Monograph of the Permian Fossils of England " (185U, p. \0'6),
Professor King, under the head of ''Family SrnopjioMisNiD^, King, 1846," writes
as follows :

" Rafinesque was the first to found a genus for shells belonging to this family.
Whether his Strophomena were ever published by himself, or it first appeared
' under the editorship of some other author, I have not been able to ascertain ;
but this is certain, that the genus was described by M. de Blainville, in his
'' Manuel de Malacologie,' 1825, aiad afterwards in the ' Dictionnaire des
Sciences Naturelles,' t. li, 1827, in both of which it is typified by the American
Strophomena rugosa, Raf, which, from its general form, and its large valve
being concave, and the opposite one convex, I have little doubt is identical
with the recently proposed Strophomena (Leptcena) planumbona, of Hall.*"

But King also included in the genus " such shells as S. alternata, Conrad,
S. Dutertrii, Murchison, S. euglijpha, Dalinan, S. planoconvexa, Hall, and several
others": a group in which are now recognized three distinct generic types
of adult characters In 1853, f Mr. Davidson followed Professor King in
assuming as the type " S. rugosa, Raf. ? = S. planumbona or iS. alternata"
This conception of the value of the genus Mr. Davidson did not modify
in any of his subsequent writings, except in his last reference to it, in
the "General Summary" of 1884. The reversal of the relative convexity
of the valves in the above species, which was indicated in Defrance's
description of S. rugosa, and which is now regarded as an important mor-
phological character, was not regarded by Mr. Davidson as of high value. The
fact that the reversed species have, in early growth-stages, the normal convexity
which is retamed throughout by such forms as S. alternata, was considered as
evidence of horaogenity ; hence he included in this genus " all species agreeing
with S. planumbona, alternata, grandis, filosa, eughjpha, funiculata, antiquata, pecten,
expansa, depressa, etc.," although in this list are species with normal convexity

* " Vide Paleontology of New York, vol. i, p. 112, pi. xxxi B, fig. 4 ; and Bull, de la Soc. Geol. de France,
2me seiie, t. v, pi. iv, figs. 3 a, b, c, d."

t Introduction British Fossil Brachiopoda, p. 105.

250 PALjEONTOLOGY OF NEW YORK.

{Rafinesquina alternata, R. expansa, Stropheodontafilosa), reversed convexity {Stropho-
mena antiquata, Strophonella eughjjiha, S.fmiculata, Orlhothetes peden), and the typical
LEPTyENA (L. depressa = rhornboidalis, Wilckens). This application of the term
Strophomena is now in general usage, but it is quite too broad for the present
requirements of classification. It is highly probable (almost certain indeed)
that the specimens described by de Blainville and Defrance under this name
had been sent by Rafinesqde from America. De Castelnau, in 1843 * in de-
scribing his species Produdus ? sulcatus, which is unquestionably an imperfect
specimen of L. rhomhoidah's, from the Corniferous limestone, says that the fossil
had been communicated to him " as a Strophomena of Rafinesque." It was
also stated, in Volume III of the Palasontology of New York (page 175), that
specimens of L. rhomboidalis in Rafinesque's collection, which came into the
hands of Mr. Charles A. Poulson of Philadelphia, were labeled with the name
Strophomena rugosa.

In 1873 Mr. Meekj provisionally retained Strophomena for Leptana rhomboid-
alis, and referred the numerous resupinate forms he there described to Hemipro-
nites, though admitting the almost certain identity of S. rugosa, de Blainville,
with Leptana planumbona. Finally Mr. Davidson, in 1884, in his last expression
in regard to this geruis, says: X"'^f''ophomem, Rafinesque, 1820, has caused much
confusion. It should, 1 think, be restricted to forms that agree with Strophomena
rhomboidalis."

CEhlert, in 1887, takes S. rhomboidalis as the type of Pander's Plectameon-
ITES, leaving under Strophomena (with S. rugosa, Rafinesque (de Blainville), as
the type), both the reversed and normally convex forms.§

It is evident from the foregoing review of the history of the name Strophom-
ena, that in justice to Rafinesque, both the genus and its type-species should
be accredited to him ; and although their interpretation and establishment are
due to DE Blainville and Defrance, we can not with propriety claim for these
authors what they had no intention of claiming for themselves.

* Essai SUV le Systeiiie Siliiririi (]e rAnrrr-iqui' Septentrioniilc, p. 90.

t PaljEontolof^y of Ohio, \iil. i, p. 7;!.

\ (ienernl Suiniiiary, \). 37!1.

§ Fischer's Maiuicl <li: f'diichyliiiiog-ie, ]i. 12S1.

BRACHIOPODA. 251

Diagnosis. Shells transversely subsemicircular or semielliptical; greatest
width along the hinge-line. Surface concavo-convex and covered with fine
radiating strige which are equal or alternate in size. The pedicle-valve is
slightly convex about the umbo, but becomes rapidly concave toward the middle
with the apex perforated, except in old age. The cardinal area is conspicuous
and nearly vertical, and the delthyrium closed by a convex plate or deltidium.
The teeth are widely divergent and are supported by plates which are produced
into elevated ridges nearly surrounding the muscular area. The latter is
relatively short, subcircular in outline, deeply excavated and divided medially
by a more or less distinctly defined longitudinal ridge wliich is often continued
over the pallial region.

The brachial valve is concave at the umbo, becoming strongly convex with
growth ; it has a much narrower cardinal ai'ea and the delthyrium is rudiment-
ary or incomplete. Dental sockets deep, and continued as narrow grooves or
indentations across the cardinal area. The crural plates are extended laterally
with a slight curve, l)ut are not supported by septa ; at their inner margins
they unite to form a callosity, upon which rests the short, bilobed cardinal
process, which scarcely extends beyond the hinge-line. The muscular surface
of this process is cordate in outline and is placed at a low angle to the plane
of the area. A low median ridge extends forward from the hinge-plate
separating two large adductor scars, in front of which are two narrow elongate
impressions. Vascular and ovarian markings frequently well defined. Shell-
substance fibrous, strongly punctate.

Type, Strophomena rugosa Rafinesque (de Blainville), lS25,^^Lept(Bna planum-
bona, Hall, 1847, as recognized by King and other authors.

Limiting the term Strophomena by this strict construction, it will prove to
be a genus of comparatively moderate vertical range, appearing so far as known
not before the age of the Trenton {Leptana filitexta, Hall, Strophomena Thalia,
Billings, S.fluduosa, Billings, S. suhtenta, Conrad), and becoming quite abundant
in the Hudson River group {Leptana planumbona. Hall, L. phmocojivexa, Hall,
Strophomena sinuata, Emmons, Hemipronites nutans, Meelv, Strophomena Wisconsin-

252 PALEONTOLOGY OF NEW YORK.

eiisis, Whitfield, Streptorhynchus cardinalis, Whitfield, Strophomena Hecuba, Billings,
Streptorhjnchus Hallie* S. A. Miller). With the close of the Lower Silurian
in America, it seems to have abruptly disappeared, though in Europe the
species S. antiqmia is al)undant in the Wenlock in England, Scotland and the
Isle of Gotland. In the Niagara and Devonian faunas its place is taken by
the geiuis Orthothetes, with which its affinites are very close.

SUMMARY.

Genus STROPHOMENES or STROPHOMENA.

1820. Rapinesque proposed the name iSTROPHOMENES without giving eitlier a diaguobis ur the
citation of any species under the genus.

1824. Defrance, Tableau des Corps Organises Fossiles, p. ti, used the generic term 8tro-
PHOMENES, citing Rafinesqde as the author.

182.5. De Blainville, " Manuel de Malacologie et Conchyliologie," vol. i, p. 513, pi. liii,
figs. 2, 2a, uses the name Strophomena, citing the name of the genus as one pro-
posed hy Rafinesqde, and also cites Strophomena rugosa, illustrating the species
and giving Rafinesqde as the author.

1827. Defrance, " Dictionuaire des Sciences Naturelles," vol. li, p. 151, and "Atlas," re-
produced the figures of de Blainville, under the name tStrophomenes rugosa,
Rafinesque.

18:il. Rafinesqde defines the genus Strophomenes (October, 1831), referring to a former
publication of 1820 ; and in November of the same year describes two species
under the names /Sir. levigata, and Str. flexiUs.

1850. Professoi' Kinc; recognized the figures of Strophomena rugosa alxive referred to, as
identical with Strophomena {Leptaena) planuinhon.a. Hall, published in 1847.

This identifii-ation has been generally accepted, and the figures of de Blainvillk,
and of the Dictionnaire des Sciences, are recognized as a fair representation of
the species.

* "The .specific name is fjiven as a compliment to Miss Hai.lie C(itton, who was the first la<iy to join
the Cincinnati Society of Natural History." — Millrr, Cincinnati Quarterly .Journal of Science, p. 148. 1874.

BRACHIOPODA. 253

Genus ORTHOTHETES, Fischer de Waldheim. 1 830.

PLATE IX, FIGS. 21-32; PLATE IXa, FIGS. 19-27; PL.4.TE X, FIGS, l-'.i; and PLATE Xl.k, FIGS. <i-22,

1820. TerthratuUtes. Schiothbim. Die Petrefacktenknmic aiif ilir. jetzig-. Standpunkt, p. 256.

1830. Orthothetes. Fi.<cher de W.^ldheim. Bull. Socivtr Iiiij). Naluialistcs lic Moscou, vol. i, p. 375.

1836. Spirifei-a, Phillips. Ilhistrations of Geology of Yorkshire, vol. ii, ji. 216, pi. 9, fig. 6.

1837. Orthi^, vox Buck. Ueber Delthyi-is oJer Spirifer iind Orthis, p. 69, i>\. ii, fig'. 5.

1837. Orthothetes, Fischer de Waldubim. Oryctograpliie dii Goiiv. ile Moscou, \). 133, pi. xx, figs. 4 a-c

1840. Spiriferf Orthis, Sowerby. Ti-aus. Geol. Soc. Lomlon, Second Ser., vol. v, pi. Ivii, figs. 7, 12.

1840. Orthis, de Verneuil. Bull. Societe Geologique de France, vol. xi, p. 2r.3.

1840. Leptw.na, J. de C. Sowerby. Mineral Conchology, pi. dcxv, fig. 1 b.

1841. Orthis, de Verneuil and d'Akchiac. Trans. Geol. Soc. London, Second Ser., vol. vi, p. 396.

1841. Spirifer {?), Phillips. PaliEoz. Foss. Cornwall, Devon and W. Somerset, p. 66, pi. xxvii, fig. 113.

1842. Strophomena, Conrad. Jour. Acad. Nat. Sci. Phila., vol. viii, \)\>. 257, 258, pi. xiv, fig. 12.

1842. Stroph(Hne)M, Vani-xem. Geology of N. Y. ; Rept. Tliii-d District, p. 122, fig. 6.

1843. Strophometia, Hall. Geology of N. Y. ; Rept. Fourtli Di,-itrict, p. 104, fig. 1 ; p. 266, figs. 2-4.

1843. Orthis, de Ko>mnck. Animaux foss. du Terrain. Carbonif. de la Belgique, p. 222, pi. xiii, tigs. 4-7.

1844. Orthis, McCoy. Synopsis Carbonif. Foss. Ireland, pi. xx, fig. IS; pi. xxii, figs. 3-6.

1845. Orthis, de Vernbdil. G6o1. de la Russie et des Montagues de I'Oural, pp. 195, 196, )il. x, fig. 18.

pi. xi. figs. 1-4.
1852. Leptcena, McCoy. British Palaeozoic Fossils, pp. 385, 388, pi. ii a, fig. 7.

1852. Leptcena, Hall. Palieontology N. Y.. vol. ii. p. 60, pi. xxi, fig. 3 ; p. 259, pi. liii, figs. 8-10.

1853. Orthis, Schndk. Palseontogi'aphica, vol. iii. p. 216, pi. xxxviii, fig. 2 ; jil. xliv, fig. 4.

1854. Orthisina, Semenow. Zeitschr. der deutschen geologischen Gesellscliaft, vol vi, pi. ii, tig. 1.

1855. Orthlnna {partiin), Davidson. Inti-od. British Fossil Bi'achiopoda, p. 104.

1855. Orthisina, The Sandbbrgbrs. Verstein. des rheiuisch. Schichtensyst. in Na.ssau, p. 61.

1856. LeptCBna, Billings. Canadian Naturalist and Geologist, vol. i, p. 138, pi. ii, figs. 16, 17.

1857. Orthis, Hall. Tenth Rept N. Y. State Cab. Nat. Hist., pp. 44, 48, 50, figs. 1, pp. 97, 137.

1858. Orthis, Hall. Geology of Iowa, pt. ii, p. 490, pi. ii, fig. 6.

1859. Strophomeiux, YkKhh. Palseontology of N. Y., vol. iii, p. 174, pi. x a. rig. 13; pi. xv, fig. 3 ;

jip. 192, 193, 111. xvii. figs. 1, 2 ; pi. xviii, fig. 3 ; pi. xxi, figs. 8, 9.

1860. StreptorhyncMis, Billings. Canadian Journal, vol. v, p. 226, figs. 12, 13.

1860. Orthisina, Streptorhynchus, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., i>p. 80, 81,

fig. 12; p. 112.

1861. Streptorhynchns, Davidson. Bi'itish Carboniferous Brachiopoda, p. 124, pi. xxvi. fig. 1; pi. xxvii.

figs. 1-5 : pi. XXX, figs. 14-16.

1862. Streptorhynchris, A. Winchbll. Proc. Acad. Nat. Sci. Phila.. vol. xiv, p. 140.

1862. Streptorliynchics, White and Whitfield. Proc. Boston Soc. Nat. Hist., vol. viii. ji. 293.

1862. fytrpptorhynrhiis. White. Proc. Boston Soc. Nat. Hist., vol. ix, p. 28.

1863. Streptorh y}i('htts, Billings Geology of Canad.%, p. 369, fig. 384 : p. 957, tig. 449.

(?) 1863. Streptorhynchu-';, David.son. Quarterly Journal Geological Soi-iety, London, p. 173. pi. ix. \\g. 19.

1863. Streptorknychus, Hall. Ti'ansactious Albany Institute, vol. iv, jip. 210, 226.

1863. Streptorhyntfnts, Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist., p. 63, figs. 1. 2.

1865. Streptorhy7ichus, Davidson. British Devonian Brachiopoda, pp. 79-S4. pis. xvi. xviii.

1865. Sireptarhynchas, A. Winchell. Proc. Acad. Nat. Sci. Phila., vol. xvii, p. 117.

1866. Crania {Psendocrania), A. Winchell. Rept. Lower Penin. Michigan, p. 92.

1867. Streptm-hynchus, Hall. Palaeontology of N. Y., vol. iv. pp. 64-74. pi. iv, figs. 11-19: jil. ix,

figs. 1-27; pi. X, tigs. 1-24.

1868. Hemipronites, Meek and Worthen. Geology of Illinois, vol. iii, p. 349, \A. vi, fig. 6.

1871. Streptorhynchiis, Kayser. Zeit,schr. der deutschen genlogi.scheii Gesellschaft, vol. xxii, p. 615,

pi. xiv, fig. 1.

254 PALjEONTOLOGY OF NEW YORK

1874. Streptorhynchiis, Hartt. Bull. Buffalo Soc. Nat. Sci., vol. i, v- 248, pi. ix.

1874. StreptorJiynchtis, Derby. Carbonif. Brachiopoda of Itaitdba, p. 37, pis. v, viii.

1874. StreptorhyncJius, Nichouson. Paleontology Piovincc of Ontario, p. 70.

1875. Heinipronitcs, Mkbk. Paloeontology of Ohio, vol. ii, p. 279, pi. x, fig. 5.

1877. Hemiprimltes, Meek. Geol. Expl. Fortieth Parallel, vol iv, p. 35, pi. iii, fig. 2; p. 62. pi. vii, tig. 2.
1877. Streptorhyncltus, Hall and Whitfield. Geol. Exploration Fortieth Parallel, vol. iv, p. 252,

pi. iv, figs. 1-3.
(?) 1878. Streptorhyiichm, Dawson. Acadian Geology, Third Edition, p. 296, fig. 96.

1879. Streptorhynchtix, Hall. Twenty-eighth Kept. N. Y. State Mns. Nat. Hist., pp. 150, 151, pi. xxi,

tigs. 26-33 ; pi. xxiii, tigs. 11-13.
1882. Streptorhynchus, Whitkikld. Annals N. Y. Academy of Sciences, vol. li, pp. 193, 200.
1882. Streptorhynchtui, Hall. Eleventh Kept. Indiana State Geologist, pp. 287, 288, pi. xxi, tigs. 26-

33 ; pi. xxiii, figs. 11-13.
1SS3. yStrKptorhyncJms. Hall. Second Ann. Rept. N. Y. State Geologist, /.l. xxxix, tigs. 21-32; jil. xl,

figs. 1-9 ; pi. xlii, figs. 16-27.
1884. Streplurhyiwhus, Walcott. Palfeonfology Eureka District, p. 117, pi. xiii, figs. 7, 16.
1884. Orthnlhetes. Wa.iqen. Salt-Range Fossils, I, vol. iv (fas. 3), p. 607, pi. Iv, figs. 1, 2.
1884. Orthothetes, Davidson. Genei-al Summary British Fo.ssil Brachiopoda, p. 379.
1887. Strepforhyiichiis, CEhlert. Etudes sur quelques Foss. Devon de I'Ouest de la France.

1887. Strophomena, Foerste. Bull. Denison University, vol. ii, p. 105, pi. viii, tigs. 31, 32, 34-38.

1888. Hemipronites, ilv,RR\CK. Bull. Denison University, vol. iii, p. 37, pi. iii, fig 24; pi. v, fig. 14 ;

pi. vi, fig. 8; pi. ix, fig. 21 ; vol. iv, pi. ii, figs. 1, 5 ; pi. iii, fig. 12.

1889. Streptorliynelaus, Beecher and Clarke. Memoirs N. Y. State Museum, vol. i No. 1.

1889. Strcpturhyiwlms, Nettelrotii. Kentucky Fossil Shells, pp. 140-142, pi. xxix, tigs. 11, 12 ;

pi. XXX!, figs. 31-33.

Diagnosis. Shells plano-convex or biconvex, sometimes becoming concavo-
convex with age. Brachial valve usually the deeper in the pallial region ;
pedicle-valve liighest about the umbo, which is sometimes much extended, and
often shows a pronounced tendency to irregular growth. Surface covered with
slender, subequal radii, which are crenulated by sharp concentric striag. Hinge-
line long, equaling, and often greater than the width of the shell ; in some
species frequently showing a tendency to auriculation at the extremities.
Pedicle-valve with the cardinal area prominently developed ; the delthyrium
covered by a thick, more or less convex deltidium, which is rarely if ever per-
forated at maturity. On the interior the teeth are moderately large, sometimes
thickened, but not supported by dental plates. The muscular area is marked
by flabelliform cardinal scars, inclosing a small adductor impression; similar to
that in Rhipidomella, but often very faint.

In the brachial valve the cardinal area is narrow, the deltidial covering
small and emarginate at the center. The cardinal process is united to the
crural plates, the wiiole forming a vertical subcrescentic process, most elevated

BRACHIOPODA. 255

centrally and notched or divided at its crest, making it bilobed or l)identate,
as seen from its inner surface ; on its outer or posterior face each apophysis is
deeply grooved, giving the entire cardinal process, from this point of view, a
distinctly quadrilobate appearance. The crural plates end more or less abruptly
in elevated points, which undoubtedly mark the place of attachment of the (;rura.
The bases of the crural plates are not produced around the muscular area.
Muscular impression tiabelliform, very much as in the other valve ; divided
medially by a low faint ridge. Shell-substance strongly punctate.

Type, Spirifer crenistria, Phillips. American example, Sfreptorhynchus Pan-
dora, Billings. Corniferous limestone.

Observations. This group of shells is distinguished from the Silurian Stro-
phomenas by the following characters: the external form is subject to greater
variation and especially so in the .convexity of the valves ; the area of the
pedicle-valve is less constant, often higher, and not infrequently irregular or
unequal on the two sides ; the umbo is often distorted, and the apex seldom
if ever perforated by a small round foramen as is always the case in young,
and generally in mature individuals of Strophomena. The surface orna-
mentation is also coarser and more pronounced, and never so delicate as in
Strophomena planumbona, and its congeners. The cardinal process does not
merely rest upon a hinge-plate or umbonal callosity, but is distinctly coalesced
with the crural plates. In Strophomena these plates make a sweeping outward
curve and do not show the point of attachment of the crura, while in Ortho-
thetes their divergence is less, and they terminate abruptly in crural apophy-
ses ; the character of the muscular impressions is quite different.

The group appears to be well-defined on the basis of these features, and
subject to little variation. As already observed, Orthothetes appears directly
upon the disappearance of the Strophomenas from the faunas of the Silurian
(Clinton); perhaps its earliest representatives, so far as known, are Strophomena
subplana, Conrad, and Streptorhynchus tenuis, Hall, of the Niagara group, followed
in the Lower Helderberg by Orthis deformis, Hall, Strophomena Woolworthana,
Hall ; becoming an abundant form in the Devonian, represented by Streptorhyn-
chus Pandora, Billings, Orthis pra.va,Y{{i\\, Strophomena Chemwigensis, Conrad, and its

256 PALAEONTOLOGY OF NEW YORK.

allies, Orthis umbraculum* Sclilotheim, and in the Carboniferous by Streptorhynchus
lens. White, Spirifer crenistria* Phillips, and others. A noticeable variation from
the tvpe of structure described, occurs in the Niagara species, Orthothetes subplanus,
where the deltidium of the brachial valve constantly increases in size, from youth
onward, while the deltidium of the opposite valve is very slightly developed.

The term Orthothetes has not come into general use, on account of the want
of clearness in its original definition. The species which are now included
under it have been generally left with the designation Streptorhynchus, but
accepting the views maintained by Dr. Waagen, the latter genus must be re-
garded as limited to the Carboniferous and Permian species. Waagen, in 1884,
was the first to place Fischer de Waldheim's name, Orthothetes, upon a sub-
stantial basis He says:

"Though this name has been quoted as applied by Evans to certain forms
already in the year 1829, yet the genus can not be considered as fairly estab-
lished before the year 1830, when in the first edition of the ' Oryctographie,'
the interior of a dorsal valve, was distinctly figured and the genus definitely
transferred to the Brachiopoda by Fischer de Waldheim. In the edition of
1830, only the interior of a dorsal valve was figured, whilst in the edition of
1837 an external view of a ventral valve is added.

" In both cases there can not remain the slightest doubt that the name was
applied to a shell very nearly related to Streptorhynchus crenistria, Phill., and
which, chiefly in the internal characters of the dorsal valve, is generically
identical with Phillips' species."f

De Waldheim did not apply a specific name to his figured species, and subse-
quently, in 1850,J he described two species, Orthothetes radiata and 0. socialis,
the former of which has a strong median septum in the pedicle-valve, and
both are probably i-eferable to the genus Derbya. De Verneuil identified
the figure given by de Waldheim in 1837 § as the Orthis arachnoidea,\\ of

* The.se species have been recognized by most Ainei-ican authors iis occurring- in the Carboniferous rocks
of America. It is <ioublful whethei' a careful comparison of European spei^imens with the American
foi-ms will prove them identical.

t Salt-Range Fossils, 1, vol. iv (fas. 3), p. 607.

\ Orthothktes ; genre de la Famille des Brachiopodes ; Bull. Society Imp. Naturalistes de Moscou,
p. 491, pi. X, tigs. 1-4. 1850.

§ Oryctographie du Gouvernement de Miiscou, p. 183, pi. xx, tigs. 4, a, b, c.

I Geologie de la Russie d'Eui'ope et des Montagues de I'Oural, p. Htlj, pi. x, tig. 18 ; pi. xi, tig. 1.

BRACHIOPODA. 2-57

Phillips,* which t'oriii Mr. Daviuson has reganludf as hut a variety of Phillips'
Spirifer crenistria.

This well known and widely distributed species (according to current au-
thority), Spirifer crenistria, Phillips {= Streptorhynchus crenistria), may hence be
taken as the type of Orthothetes ; and since tliis fossil, as recognized, is sul)-
ject to considerable variation in the regularity and eleviition of the uinl)o of the
pedicle-valve, which is usually normal and symmetrical, but sometimes much
distorted, it opens the genus to the reception of species in wbicli this irregular-
ity is usually present, and to those in which this condition does not appear.

Genus H I P P A Pt I 0 N Y X, Vanuxem. 1842.

I'LATli IX, FIGS. K-3li; ANL> PLATK XVa, FICiS. il-U.

183S. LepicBna unguiformus, Conrad. First Ann. Rept. PaUcont. Dcpt. N. Y. State GftoL Snrvey,

ji. 112 (not descrilied).
1840. StropJtomena U7iguifo)-inis, Conrad. Thinl Ann. Rept. Palieont. Pi'pt. N. Y. State (xeoL Sin'vey,

p. 203 (not described).
18-11. Atrypa u/igitifoniiia, Conrad. Fifth Ann. Rept. Palseont. Dcpt. N. Y. State Geol. Survey,

p. 36 (not desciibed).

1842. Hipparkmijx proxhiMS, Vanuxem. Geolog:y of N. Y. ; Rept. Third Dist., p. 124, tig-. 2i), No. 4

(not H. cimsimUis nor H. similarls, Vanuxbm, p. 124).

1843. Atrypa imgiiifonnis, (Conrad) Hall. Geology of N.Y.; Rei)t. Fourtli Dist., p. 149, tig. 60, No. 4.

1859. Oithis ?iipparioayx, Hall. Pal;i;ontoiogy of N. Y., vol. iii, p. 407, pi. lxx.\ix, tigs. 1-4; ]il. xc,

tigs. 1-7 ; pi. xci, tigs. 4, 5 ; pi. xciv, tig. 4.

1860. Oi-thls unguiformis, Em.mons. Manual of Geology, p. 129, tig. 11!5.

1881. Orthis unguiformis, Davidson. '? Bi'achiopoda Budleigh-Salterton Pebble-bed, j). 347, pi. xxix, fig. 1.

1883. ^trepUrrhynclms lilppanonyx. Hall. Second Ann. Rept. N.Y. State Geologist, pi. 39, figs. 33-36.

Not Orthis liippariony.):, Schnuk. 1853. Palsontographica, vol. iii, p. 217, pi. xl, tig. 1.

Not Orthis hipparhinyxK Davidson. 1865. British Devonian Brachiopoda, p. 90, pi. xvii, figs. 8-11.

The remarkable shell described by Dr. Vanuxem as Hipparionyx proximus, so
far as known, is the only representative of a peculiar association of streptor-
hynchoid characters. The name Hipparionyx has not been in general use,
though, in the broad application of the generic term, which has been customary
in this group of shells, it should have had precedence over Streptorhynchus.
Schnur, in 1853, regarding what he believed to be a similar shell from the
Eifel as an Orthis, took the liberty of changing Vanuxem's name for the species

* Geology of Yoi-kshire, vol. ii, p. 220, pi. xi, fig. 4. 1836.

t British Carboniferous Brachiopoda, p. 127; British Devonian Brachiopoda, p. 81.

258 PALEONTOLOGY OF NEW YORK.

to Orthis hipparionijx, and l)y this designation the species has become generally
known. It will, liowever, be necessary to return to both Vanoxem's generic
and specific terms.

Diagnosis. Shell large, subhemispherical. In youth the pedicle-valve is
very slightly convex, but at maturity it is depressed, or concave, over the pallial
region. The brachial valve is always very convex. Marginal outline of the
valve subcircular. On the pedicle-valve the hinge-line is straight but short, the
cardinal area low, and the beak retrorse. The delthyriuni is broad, and covered
by an imperforate convex deltidium. The teeth are moderately large and are
supported by lamellae which extend to the bottom of the umbonal cavity, and
are produced into strong ridges entirely surrounding the muscular area. This
area is very large, having the structure of that in extreme examples of Rhipi-
DOMELLA, such as OHhis musculosa, and is composed of broad, flabellate diductors
enclosing an elongate or cordate adductor impression There is a low median
septum in the umbonal cavity, separating the arms of the cardinal process of the
opposite valve, but it is quite short, disappearing at the adductor scar, though
sometimes reappearing in front of it.

In the brachial valve there is no cardinal area. The cardinal pro-
cess has essentially the same structure as in Orthothetes and Derbya, but
is very high, its two branches completely traversing the umbonal cavity of
the opposite valve ; it is supported by a short, median septum, and laterally
by strong crural plates which extend for a short distance along the margins
of the muscular impressions; these are usually quite faint and undefined,
occupying a much smaller area than in the pedicle-valve, and leaving arbores-
cent markings as in some species of Stropheodonta. On the interior of both
valves the margin is sharply pectinated, or crenulated, the crenulations on the
brachial valve extending to the base of the cardinal process, and in the
pedicle-valve extending for a considerable distance on the cardinal area. Sur-
face of both valves covered with fine sharp radiating striae.

Type, Hipparionyx proximus, Vanuxem.* Oriskany sandstone.

* Va.ncxkm nUo citeil t\V(i other species of IIippahionyx, H. voiUilmUis and //. similaris, and on page Vii
of his report gi\-es a figure probably iiiteiulod for one of these species, under the name of H. consimilaris.
This latter la a large, expanded form of Atry-pa reticuJarli, from tlie Onondaga limestone.

BRACHIOPODA. 259

Observations. The distinguishing characters of this genus are, («) its orthoid
external features, and muscular scars in the pedicle-valve ; (b) the presence of
strong dental lamellae which are not known among the streptorhynchoids, ex-
cept in Meekella ; (c) the absence of any cardinal area on the brachial valve ;
{(1) the presence of a slight median septum in both valves. Hipparionyx proximus
is an abundant fossil in the Oriskajiy sandstone of New York, occurring also at
Cumberland, Maryland, and in the arenaceous layers at the base of the Upper
Helderberg in the Province of Ontario. The form from the Eifel referred to
this species by Schnur is regarded by Kayser* as Orthothctes umbraculum, and the
shells thus identified by Davidson, from the beds of Looe, Cornwall, and the
Budleigh-Salterton pebbles, can not belong to the Oriskany species.

Genus KAYSERELLA, gen. nov.

1853. Ortbis, Schnur. P;ila;ontographicii, vol. iii, p. 212, pi. xxxvii, tig'. 8; pi. xxxviii, fly. i ; p. '218,

pi. xlv, fig. 9.
1871. Streptorhynchuft ? , Kayser. Zeitsclii'ift der <leiitschen grolog-iscli(>n rTesellsch.aft, vol. xxiii, p. (il7,

pi. xiv, figs. 2 a, h, c, d, e.

1885. StreptorhyncUus'f, Maurer. Kiilke von Waldgh-mes, p. 138, pi. v, tig. 10.

1886. iStreptorhy7ichusf,'^Bti-iuKOFF. Faniia des Devon. Syst. iiii uordw. uml central Russl., p. 65,

pi. ii, tig. 4.

The species described as Orthis lepida hy Schnur, in his work on the Brachi-
opoda of the Eifel,f has been shown by Professor Kayser to be a streptorhynchoid
shell, with a covered delthyrium on the pedicle-valve and a very prominent
median septum in the brachial valve, dividing the internal cavity much as in
the Devonian forms of Scenidium, where the central plate is greatly developed.
This is a feature not met with elsewhere among the fossils of this group, and
though the internal characters of the species remain undefined, except the sep-
tum, this character alone must exclude it fi'om any of the generic groups now
recognized. That Professor Kayser recognized its generic value, is evident
from his language :

" Strept. lepidus steht durch Gestalt, Form der Rippon und deutliche Perfora-
tion der Schale den Arten des Formenreihe der Orthis circularis zwar nahe,

* Zeitscbr. der deutscheii geologi.scUeii Gesellschaft, vol. xxiii, p. 010. 1871.

t Zusammenstellung und Beachreibung saniratlicher im Uebergang.sgebirge der Eifel vorkomnienden
Brachiopoden, nebst Abbildnngen derselben ; Palaoutographiea, lU. cit.

260 PALEONTOLOGY OF NEW YORK.

entfernt sich aber clurch das grosse Dorsal septum unci die Ueberdeckung der
Stielcffnung doch so sehr von denselben, das ich es nicht gewagt habe, die
Form jener Reihe einzufugen. Beide genannten Chara,ktere entfernen unsere
Art von den echten Orthis-Arten iiberhaupt, und der letztere, das Pseudodelti-
dium auf der Ventral area, spricht f lir ihre Stellung bei Strepiorhijnchus. Dock
hat der echte Streptorhynchus ein Pseudodeltidium audi auf der Dorsal area,
welches ich bei lepidus vergeblich gesucht habe."

" Figs. is. K;, 17. Stivptol-hi/nrjais'! li'pi'his. Aricr Iv.vVSElt.

Though represented by only a single known species the form is an important
one in the series of streptorhynchoid genera and it is therefore separated under
the name above proposed.*

DiAGNOSis.f Shell subsemicircular ; hinge-line nearly equaling in length the
greatest width of the shell ; convexity normal. Pedicle-valve more convex
than the brachial; area moderately high; delthyrium covered by a convex
plate. Brachial valve slightly convex ; area narrow ; delthyrium covered.
In the interior, a large, triangular median septum extends almost to the bot-
tom of the opposite valve. Surface with a slight median ridge and furrow
on brachial and pedicle-valves respectively; covered with sharp plications,
increasing by intercalation near the margin.

Shell-substance punctate.

Type, Orthis lepida. Schnur. A somewhat rare species in the " Crinoiden-
schichten" of the Middle Devonian at Pelm and Gerolstein.

* The publication of this genei-ic description in the present volume has received the approval of Pro-
fessor Kay.skh, atid the name proposeil is in recognition of the emiuont servi<'es of that author in Geolog-ical
and Palieontolojjical Science.

t Deiivinl fr'oni Kayskr's description of the type-si)Ocies.

BRACHIOPODA. 261

Genus DERBY A, Waacen. 1884.

I'LATK X, FIUS. 10-17; I'J-ATK XI, KIGS. 1-5, l*-2-2; PLATE XIa, KIGS. SKil); i-I.ATE Xlis, FIGS. 1-8, IG, 17, 'if, 24;

AND PLATE XX.

1836. Spirifer, Phillips. Illutitr. Geolofjy of Yorkshire, vol. ii, yil. ix, f\g. 5.

1844. Oiihij), McCoy. Synopsis Carboiiif. Fo.'ssils of Shetland, p. 123, pi. xxii, fijf. 1.

1852. Oi-thh; Owbn. Geological Rept. of Wisconsin, Iowa ami Minnesota, pi. v, fig. 11.

ISSS. Orthhina ipartim), Davidson. Introd. British Fo.ssil Brachiopoda, p. 104.

1855. Leptmna, McCoy. British Paleozoic Fo-ssils, p. 452.

1858. Orthix, Hall. Geology of Iowa, pt. ii, p. 640, pi. xix, fig. 5; p. 173, pi. xxviii, tig. 5.

1858. Orthhina, Meek and Hatden. Proc. Acad. Nat. Scienc'es Phila.. vol. x, p. 161.

1860. Ortlds, McChesney. New Palaeozoic Fossils, p. 32.

1861. Streptorhynchu.1 {partim}, Davidson. British Carb. Brachiopoda, p. 124, pi. xxviii, tigs. 2-7, fl.
1864. Hemijjronites, Meek and Hayden. Rept. Palreont. Upper Mis.sonri, p. 26, pi. i. tig. 7.

1868. Hemipronite.'i, McChesney. Trans. Chicago Academy Sciences, p. 28, pi. i, figs. 5, 6.

1872. HcmipronUeis, Meek. Rept. Palaeontology Eastern Nebraska, p. 174, pi. v, fig. 10 ; pi. vii, fig. 1.

1873. Hciiiipronites, Meek and Worthen. Geol. Surv. Illinois ; Pahnont., vol. v, p. 570, pi. xxv, fig. 12.

1874. Streptnr?/ynchns, Derby. Carlioniferous Brachiopoda of It.aitulia, p. 32, pis. vii, viii.

1878. StreptorliyncliKS, Abich. Bergkalkfauna ans der Araxesenge bei Djoulfa in Annenien, p. 73.

1883. jStreptorhynckiui, il.Ki.h. Second Ann. Rept. N. Y. State Geologist, ]>1. xl. tig.s. 10-17; pi. xli,

figs. 1-3, 18-22.

1884. Derbyia, Waagen. Palaeontologica Indica, Ser. xiii, vol. i, pt. iv, jip. 576, 591-607, pi. Ii, fig. 1 ;

pi. Hi, figs. 1-3; pi. liii, figs. 1-5; pi. liv, figs. 1-4; pi. Iv, fig. 3.
1887. Derbya, CEulert. Fischer's Mannel rle Conchyliologie, p. 1285.
1887. Htmipronites, Herrick. Bull. Denison University, vol. ii, p. 50, pi. 2, fig. 19.

Diagnosis. General character of the shell as in Orthothetes. The external
form is more variable, being usually plano-convex, rarely concavo-convex, the
pedicle-valve often more elevated and subpyramidal, becoming irregular in its
growth toward the apex. The interior of the pedicle-valve bears a high median
septum, extending longitudinally through the center of the muscular area,
which is from one-third to two-thirds the length of the valve ; near the apex
of the umbonal cavity it unites with the dental plates forming a small trian-
gular chamber beneath the deltidiuni. In old shells this cavity is often filled
by a testaceous secretion. The dental plates do not extend to the bottom of the
rostral cavity except near the apex.

Brachial valve broad and regularly convex, or sometimes with an undefined
median depression, and showing a tendency to auriculation. Cardinal area
linear ; the crural plates are abruptly elevated, and unite to form a strong
erect cardinal process, which is distinctly bilobed at the summit; each lobe
being slightly notched at the summit and distinctly grooved along the posterior
face, the grooves uniting in a wider one at the posterior base of the process.
Midway in their length these crural plates are marked by a transverse ridge

262 PALEONTOLOGY OF NEW YORK.

which terminates on their anterior face in points for the attachment of the crura;
on the inside of the dental sockets there is a distinct, sometimes strongly de-
fined ridge, extending along the lateral margin of the broad tlabelliform muscular
area, and gradually becoming obsolete. There is also a slight median ridge
which becomes obsolete below the middle of the muscular area. Surface marked
by strong, sharply elevated radii, which alternate with finer ones, all being
crenulated, and the intermediate space cancellated by fine concentric striae.

Type, Derbya regularis, Waagen. Upper Carboniferous. American example,
Orthisina crassa, Meek and Hayden. Upper Coal Measures.

Observations. The validity of this genus rests entirely upon the presence
of the median septum in the pedicle-valve. In some other groups of the
brachiopods one miglit question the advisability of giving so much im-
portance to a feature of this kind, which is often very variable even in a given
species, but the study of the streptorhynchoid shells has led to the endorse-
ment of Dr. Waagen' s views in regard to the value of septal characters in this
group. In none of the other genera, Strophomena, Orthothetes, Meekella,
Streptorhynchus, does such a septum exist, and so far as known, it exists only in
this very restricted group of fossils which first appears in the Carboniferous and
disappears in the Permian. In the character of the cardinal process and crural
plates there is no essential difference between Derbya and Orthothetes. Species
of the former genus are often of very great size (Z). grandis, D. regularis, Waagen,
D. rolmsta, D. Keokuk, Hall), and in consequence tlie cardinal process becomes of
very sti'iking proportions, but structurally not different from Orthothetes, as
shown by all the smaller species of Derbya Of American species to be placed
in this genus are the Orthis Keokuk, Hall, from the Keokuk limestone of the Lower
Carboniferous, Orthis robusta. Hall, from the Lower Coal Measures of Illinois,
Hemipronites crassus,* Meek and Hayden, also from the Coal Measures, and
Streptorhynchus Correanus, Derby, from the Carboniferous limestone of Itaituba,
Province of Para, Brazil. In the Carboniferous of Great Britain occur the
species Spirifer senilis, Phillips, and Orthis cylindrica, McCoy. Dr. Waagen has

* Meek regarded McChbsijey'& species, Hemipronites Lasallensis and H. Richmondi, described in 1860,
from the Coal Measures of Illinois, as synonymous with ff. crassus. See Palsont. Eastern Nebraska, p. 17-1.

BRACHIOPODA. 263

added six species from tlie Carboniferous or Permo-Carboniferous of the Salt-
Range, and Abich, in 1888, described two forms from Armenia as varieties of
Slreptorhynchtis crenistria, Phillips, viz., S. eusarcus and S. incurvus, both of which
Dr. Waagen regards as belonging to Derby a. On the basis of these forms he
has made a conventional subdivision of the group into Camerati and Septati;
in the former, the dental lamellse do not extend along any part of the rostral
cavity; in the latter are species like D. Correana and D. robusta, where the me-
dian septum unites at the apex of the umbonal cavity with the dental lamellse
forming a minute triangular vault. This peculiarity is most conspicuously
developed in Derbija Correana, and is a natural result from the great height of
the cardinal area.* In Derhya crassa and others of the Septati where the rostral
cavity has become largely filled up by testaceous matter, a slight abrasion of
the beak shows this union of the septum with the dental lamellae.

On the internal surface of a brachial valve of Produdus Nebrascensis, from
the upper Coal Measures, near Kansas City, Missouri, there occurs a little
group of twelve minute pedicle-valves, all closely affixed to their host by their
entire external surface. With but two exceptions, the members of this cluster
are oriented alike, having their hinge-lines parallel to the hinge-line of the
Productus, but their anterior margins directed toward the posterior margin of
the latter. Three of the individuals show a broad cardinal area, and deltidium,
and bear a conspicuous median septum in the muscular area, thus having the
characters of Derbya. Their gregarious occurrence and small size are evi-
dences of immaturity. The frequent distortion of mature pedicle-valves of
Derbya, and the occasional retention of a cicatrix at the apex, are evidences
of an adherent condition in early stages of growth, which are confirmed by this
interesting specimen, of which an illustration is given upon Plate XI b.

Two interesting new forms of this genus are described and illustrated in
this volume, viz., Derhya Broadheadi and D. Bennetfi, from the Upper Carbon-
iferous limestone of Missouri and Kansas, the former a large species with but a
moderately high area, the latter a smaller form having much the expression of
a Meekella, with very high area, and an extremely high internal septum.

* See tig-ure on Supplementary plate.

264 PALEONTOLOGY OF NEW YORK.

Genus MEEKELLA, White and St. John. 1868.

I'LATK X, I'lGS. 18-23; and PLATE XIH, PRJS. IS-M.

1837. ChoristUen (partim), FisctiBR de Waldueim (fuU Vebneuil). Oryctogr. du Gouvern. ile Moscou.

p. 141, pi. xxii, fig'. 4.
184.5. Orthis. DE Verneuil. Geol. de la Russie d'Eui-ope et de.s Moutag-nes de rOural, pp. 192-194, pi. ix,

Hgs. 2, 3 (ProducUiS, Eichwald. Coll. du Corps des Mines de St. Petersb.).

1857. rticalala. Cox. Owen's Rept. Geological Survey Kentucky, vol iii, p. 568, pi. viii, fig. 7.

1858. Orthisinn, Swallow. Trans. St. Louis Academy of Science, vol. i, p]). 183, 219.
18.59. OHhinhia, Meek .and Havden. Prnc. Acad. Nat. Sci. Pliila., p. 2ti.

1861. ,Strepfurhync}ms, Newberry. Lieut. Ives' Rept. Colorailo River; PaliEontoIogy, pt. iii, chap, xi,

p. 126, pi. i, fig. 5 ; pi. ii, figs. 11-13.
1806. Orthis, GEiNrrz, C'jirbon. and Dyas in Nebraska, p. 48, pi. iii, figs. 22-24.
1868. Meekella, White and St. John. Ti-ans. Chicago Academy Sciences, vol. i, p. 120, figs. 4-6.

1872. Meekella, Meek. PaliEontology of Eastern Nebraska, p. 175, pi v, fig. 12.

1873. Meekella, Meek and Worthen. Geological Survey of Illinois, vol. v. p. 571, pi. xxvi.

fig. 21.

1874. Meekella, Bayan. Bull. Societe Geol. Fi-ance, Ser. 3, vol. ii. p. 412, pi. xvi, fig. 3.

1873. Meekella, White. Wheeler's Rept. Expls. .-md Surveys West 100th Merid., vol. iv, pt. i, p. 126,
jil. ix, fig. 4.

1883. Strcptorhynchm (Meekella), Hall. Rept. N. Y. State Geologist for 1882, pi. xl, figs. 18-23.

1884. Meikella, White. Thirteenth Report State Geologist Indiana, p. 1.30, pi. xxvi, figs. 12-14.
1884. Meekella, David.son. General Summary of British Fossil Bi-achiopoda, p. 379.

1884. Meekella, Waacbn. Salt-Range Fossils, vol. i, pi. iv, p. 576.

Diagnosis. Shell robust, biconvex, often subpyramidal. Hinge-line straight
and shorter than the greatest width of the shell. On the pedicle-valve the
cardinal area is often greatly elevated and distorted; the delthyrium is covered ;
the convex portion of the deltidium being much narrower than the space
between the dental ridges. In the interior the teeth are prominent and sup-
ported by septiform dental lamellae which reach the bottom of the umbonal
cavity and extend forward for one-third or one-lialf the length of the shell.
The brachial valve has a full, gibbous umbo, and a rudimentary or linear cardi-
nal area. On tlie interior are two divergent lamellae or crural plates, which
are extended forward for more than one-third tlie length of the valve, support-
ing a high, erect cardinal process, which sometimes reaches almost to the apex
of the umbonal cavity in the opposite valve. This process is a somewhat
curved, thin, crescentic plate, bearing on its summit two slender median
apophyses, l)elow which are two stouter lateral projections having the form of ex-
tended, rounded lobes, which form the bases of the crura. Surface of the valves

BRACHIOPODA. 205

marked with coarse costaB, which, with the interspaces, are covered by line
radiating plumose striaj. Shell-substance fibrous, punctate.
Type, Plicatula striatocostata, Cox. Ui^per Carboniferous.

Observations. Meekella embodies the extreme development attained by
certain features in the streptorhynchoid brachiopods. It has been noticed that
in Derbya the dental lamellae are septiform only in the apex of the umbonal
cavity ; that in Hipparionyx this character is more positive. In Meekella the
great development of these lamellge is subject to some variation, depending
primarily upon the depth of the umbonal chamber. Dr. Waagen remarks* that
in an American specimen labelled Meekella striatocostata, he was unable to discover
any trace of dental lamellaa, and infers, from this fact, that there is probal)ly
present, in our Upper Carboniferous fauna, a species of the type of Streptorhynchus
pediniformis, Davidson, a form remarkable for having the peculiar exterior char-
acters of Meekella, and which was thus referred by Mr. MEEK,f who also
observed the absence of septa in the Indian species, S. pedinifonnis, and infer-
red a generic difference between it and Meekella in case this absence were not
accidental.

The remarkable cardinal process in this genus is a I'eature of important
significance. In the pectenoid species of Streptorhynchus, such as that already
mentioned! and S. HalUanus, Derby (see Plate XI, figs. 6-17), it does not
appear that there is a very close approach to Meekella in this respect, though
herein the Brazilian species is not in strict agreement witli Streptorhynchus
pelargonatus.

Meekella striatocostata is not an uncommon fossil in the Middle and Upper
Coal Measures of the interior and western States on the east side of the Rocky
Mountains ; but is not known in localities east of Illinois and Kentucky, " nor
anywhere in the Lower Coal Measures."§ This species was described under

* Salt-Range Fossils, Brachiopoda, p. 589.
t Palseontolog-y of Eastern Nebraska, p. 170, \>}. v, fig. 16.

t Waagen has described this i)rocess in S. pecthiiformis as iiaviiig jirecisely the same structure as that
in jS. pelargonatu.'! according to the figures given by Davidson.

§ See Final Report U. S. Geological Survey of Nebrsiska, p. 177. 1S72.

266 PALjEONTOLOGY OF NEW YORK.

the name Orthisina Missouriensis by Swallow, and it is probably identical with
0. occidentalis of the same author. Dr. Newberry has described* the species
Streptorhynchus pijramidalis, and S. occidentalis ; the former of these may be iden-
tical with Meekella striatocostata, though the original specimen appears to be ot
very large size and of rather more pronounced plication. Figures of the
original specimens of the latter species are given on Plate XI c, showing it to
be very distinct from M. striatocostata, and the largest known representative
of the eenus. In 1845 de Verneuil described from the middle and lower
Carboniferous limestone of Russia, Orthis eximia,j and O. Olivierana, both
of whicli unquestionably belong to Meekella, the former being of the type
of M. striatocostata, the latter an evenly striated shell without the radiating
cost£fi, a type of surface ornamentation otherwise unrepresented in this group.
Still another species has been described by Bayan,± M. Garnieri, from some
fossils collected in the valley of the Yangtsee-Kiang, China, by the late M.
Francis Garnier.

* Ives' Repoi-t Colorado River of the West, p. 126.

t According- to db Vernbdil this is the Productus exhii'ms of von Eichwald, and the Choristites Wal-
cotti of Fischer db Waldhbim.

I Sur queliiues Fossiles Piileozoiqiies de Chine, op. cit.

BRACHIOPODA. 267

Genus S T R E P T 0 K H Y N C H U S, King. 1850.

I'LATE XI, FIGS. 6-17; PLATE XlB, FIGS. 9-15; anM) PLATE XX.

1S16. TerebratulUes, Schlotheim. Denkschr. d. K. Akatl. U. Wissonschaft, in Muiicheii, vol. vi, p. 28,

pi. viii, figs. 21-24.
1837. Oi-this, VON BccH. Ueber Delthyris oiler Spirifer und Orthis, p. 62.
1848. Ch'this, Geinitz. Veistein. d. Deutsch. Zechsteingebirg-es, p. 13, pi. v, fig.s. 11-15.
1850. Streptorhynchus, Kinq. Monogr. Pei-m. Fossils Englaiul, p. 109, pi. x, figs. 18-28.
1853. Ori?mina, Davidson. Inti-od. British Foss. Brachioi>oda, p. 104, pi. viii, fig. 156.
1857. ISt.reptorhynckvs, David.son. British Permian Bi'achiopoda, p. 32, jil. ii, tigs. 32-42.

1861. Orthis, Geinitz. Dyas, vol. i, p. 92, pi. xvi, figs. 26-34.

1862. Streptor?iynchtiS, Davidsox. Quart. Journ. Geol. Society, \ol. xviii, p. 3, pi. i, tigs. 17, 18.
1863., Streptorhynchits, de Koxinck. Fossiles Paleoz. de I'lnde. p. 37, pi. x. fig. 17.

1871. Orthix, QnENSTBDT. Petrefaktenkunde Deutschlands; Brachiopoden, p. 548, pi. iv, tigs. 51-56.

1874. StrepU>rhyiuhu3, Derby. Carbonif. Bi-ach. Itaituba, p. 35, jils. v, viii.

1880. Streptoi-kynclma, Davidson. Biitish Permian Brachiopoda, Suppl., \t. 243, pi. xxx, tig. 3.

1884. StreptwJiynvlms, Waagen. Salt-Range Fossils, vol. i, pp. 576-5P1, pi. 1, figs. 3-9; pi. Iv, tigs. 4-13.

1887. StreptorhyncJiVS {Orthothetes), CEhlert. Fischer's Manuel de Conchyl., Brach., p. 1284, fig. 1050

Diagnosis. Shells somewhat trihedral and subpyraniidal, with base convex ;
hinge-line shorter than the greatest width of the valves. Pedicle-valve having
the beak acute and often incurved and distorted. Cardinal area high, some-
what incurved ; delthyrium covered by a broad, imperforate, depressed-convex
deltidium. The interior of the valve with low dental ridges terminating in
teeth of moderate size ; these ridges are not septiform and do not continue to
the bottom of the umbonal cavity ; there is no median septum ; muscular scar.s
strong and flabelliform.

In the bracliial valve the cardinal area is linear, the crural plates are vertical
and abruptly elevated on their anterior edges, forming points of attachment
for the crura; these unite to form a subcrescentic plate, from the center of
which arises a broad, erect cardinal process, which is deeply divided into two
lobes, each of which is faintl}' grooved at its summit and on the posterior face;
muscular area small, divided medially by a low ridge. Exterior surface
covered by fine radiating striae.

Type, TerebratulUes pelargonatus, Schlotheim. Permian.

Observations. According to Dr. Wa.a.gen's determination it will probably
be necessary to restrict this genus to species agreeing with the above mentioned
characters of S. pelargonatus. Though the relationship of this group with the

268 PALEONTOLOGY OF NEW YORK.

genera Derbya and Orthothetes is very close, there are appreciable differences:
(1) in the general form of the shell; (2) the absence of true dental lamellae;
(3) the absence of a median septum in the pedicle-valve ; (4) the character of
tlie divaricating cardinal process. The structure of the last-mentioned feature
differs from that in Orthothetes and Derbya, in being thinner, sharper, much
higher and more deeply furcate The grooving of the posterior faces of the
tips of the cardinal process, as illustrated by Davidson,* gives to this organ a
very similar character to that in Triplecia Ortoni.

As thus restricted, the genus has a comparatively meagre representation.
Seven species have been described from the Permo-Carboniferous of the Salt-
Range of India. Dr. Davidson had previously described one species, S. pectini-
formis, from the same country; and Dr. Derby described S. Hallianus, from
Itaiti'iba, Brazil. The only species known in European faunas is S. pelargoriatus,
and in North America the genus, so far as our present knowledge reaches, is
represented by a single species, S. Ulrichi, sp. nov. from the Chester limestone.
Dr. Waagen has divided the genus into two sections: I. Simplices, in which the
surface is simply covered with radiating striae; II. Plicati, in which the surface
is plicated as well as striated, as in Meekella. Of the former, S. pelargonatus,
Schlotheini, is a typical representative, and »V. Hallianus, Derby, of the latter.
In regard to the range of Streptorhynchus, this author observes :

" The genus seems in Europe to be restricted to the Permian period, though
perhaps .some forms that occur in the Mountain limestone might also belong to
it. In the Salt-Range the different species are distributed through the whole
mass of the Productus limestone, from the lowest to the topmost beds. The
first section, the Sitnpliccs, is restricted to the lower and middle divisions whilst
the second section, the Plicati, chiefly occurs in the upper divisions."

* Permian lir.ic.hiopoila, pi. ii, tig-. 39.

BRACHIOPODA. 269

Genus TRIPLEGIA,* Hall. 1858.

PLATE XI 0, FIGS. 1-22.

1842. Terebratuki, von Eichwat.ii. Ui-welt Russlamls, vul. ii, p. 4i1. plate ii, fig's. G a, b, c.

1842. Atrypa, Emmons. GiMilogy of N. Y. ; Rept. .S(m'oiu1 Disl,i-i<-t, ji. iiDfi, fiff. 6.

1845. Spirifer, de Vernbiui,. Geol. Russ. et iJes Moiit. df r()iii:il. p. M'.i, pi. viii, fig-. 7.

1846. Orthis. Producta, McCoy. Synopsis Siluri;ui Fo.ss. li-dliiinl, p. 2;"), pi. iii, i\g. 3; p. 30, jil. iii, liy. 12.

1847. Atrypa, Hall. PaliBOutology of N. Y., vol. i, jip. 137, 13il, pi. xxxiii, fig-s. 1,2; pi. xxxiii*, ^g. I.

1848. Orthis, Phillips and Salter. Mem. Geol. Sm-v. United Kin^jdom, vol. ii. p. 2.S9.
1852. Hemithyris, McCoy. Biitish Paleozoic Fo.ssils, p. 201.

1858. Triplesia, Hall. Twelfth Kept. N. Y. State Cab. Nat. Hist., p. 44. fit;-s. 1-3.

1859. Spirifcr, von Eichwald. Lethaea Ro.ssiea, vol. i, p. 697.

1859. Triplesia, Hall. PaliEontolog-y of N. Y., vol. iii, pp. 522, 523. figs. 1-3.

(1) 1861. Camarella, Billings. Canadian Naturalist and Geologist, vol. vi, p. 318, tig. 3.

(1) 1863. Cmmrella, Billings. Geology of Canada, p. 231, fig. 247.

0) 1865. Camarella, Billings. Palseozoic Fossils, vol. i, p. 220.

1866. Orthis, Salter. Mem. Geol. Surv. United Kingdom, vol. iii, |i. ()97.

1869. Triplesia, Davidson. British Silurian Brachiopoda, pp. 197-201, pi. xxiv, figs. 29, 31, 32,

pi. XXV, figs. 3-5.

1871. Orthis, Davidson. Bi'itish Silurian Brachiopoda, p. 273, jil. xxxvii, tigs. 3-15.

1872. Dieraniscus, Meek. American Journal of Science, Third Ser., vol. iv, p. 280.

1873. Triplesia, Meek. Geological Survey Ohio ; Palajontology, vol. i, p)i. 17(i 179, pi. x\-. lij^s. I a-k.
1877. Triplesia, Whitfield. Ann. Re])t. Geol. Survey of Wisconsin, ]>. 51

1882. Triplesia, Whitfield. Geology of Wisconsin, vol. iv, ji. 172, pi. x, figs. 1, 2.

1883. Triplesia, Davidson. British Silurian Brachiopoila. Sujipl., pji. 141-147.
(?) 1884. Triplesia, Walcott. Palsontolog-y Eureka District, p. 75, pi. xi, figs. 7, 8.

1889. Triplesia. Whitfield. Bull. American Museum Nat. Hist., vol. ii. No. 2, p. 43, pi. vii, figs. 5-8.
Compare Strcptis, Davidson. Geological Magazine, vol. viii, p 150, pi. v, tig. 13. 1881 ; and Briti.sh

Silurian Brachiopoda. Sn]i))l., p. 139.

Diagnosis. Shell trilobate, transverse, unequally biconvex. Hinge-line
straight and quite short. Pedicle-valve shallow, convex about the beak, but
depressed anteriorly by a broad and deep median sinus ; cardinal area low,
erect and well defined ; delthyrium covered by a narrow, convex plate, with a
circular foramen at the apex. In the interior the teeth are well developed and
supported by short dental lainellse longitudinally dividing the umbonal cavity
near its apex. Muscular area small, comprising two lateral scars, separated by
a longer central adductor impression. The brachial valve is very convex, and
bears a strong median fold. The cardinal area is very narrow and the beak
closely incurved. In the interior is an erect cardinal process, which is deeply

* The derivation of the term "Triplesia," as it is currently written, was given in the original descrip-
tion as from TpiTrXdaiog- = triplasius. The correct form of the word, therefore, woidd have been Tripi.asia,
but this term appears to have been already in use. Dr. CEhlert has suggested the <-hange to Thh'I.kiia,
which involves a derivation from a different root, rfjnTXsK/'i^'= triplex.

270 PALAEONTOLOGY OF NEW YORK.

bifurcated, the distal extremity of each branch bearing a single deep groove.
This process is supported on a subrostral callosity, which also bears two short
spiniform crural points at its base. Shell-substance fibrous, impunctate (?).
Surface with obscure concentric growth-lines, and fine radiating striae on the
inner laminsB ; in rare instances there are radiating lines on the exterior.
Type, Alrypa extans, Emmons. Trenton limestone.

Observations. The species of this genus appear to be subject to consider-
able variation, and there still remains some doubt as to the proper limitation
of the group. Triplegia, Streptis and Mimulus are terms which, with a little
latitude, one might regard as of equivalent value. Adhering, however, pi-etty
strictly to the type of structure exemplified in Triplecia extans, we shall
have for Triplegia a much more compact and homogenous division, comprising
such species as Atnjpa extans, Emmons ; A. cuspidata. Hall ; A. nucleus. Hall ;
Orthis insularis von Eichwald ; Triplesia Wenlockensis, Davidson, and perhaps
Camarella calrifera, Billings,* and some others.

Triplecia Ortoni, Meek, the type-species of this author's genus, DiCRANiscus,f
is a large, ponderous shell, retaining the subtrihedral form, and essentially the
internal characters of Triplegia, though the dental lamellas are obscured by
complication with the thick testaceous deposit usually found in the umbonal
cavities of both valves. There is apparently no good reason for not regard-
ing T. Ortoni as strictly congeneric with T. extans.

Mr. Davidson has referred to Triplegia, with some doubt, a number of species
whose precise affinities have yet to be demonstrated. Of these are Atri/pa?
apiculata, Salter ; Triplesia ? Maccoyana, Davidson ; Atrypa ? incerta, Davidson ;
Producta monilifera, McCoy, and Triplesia? Graya, Davidson. J In Atrypa (Tri-

* The relations of this species are not well understood. The external foi-m cf the shell is that of T.
extans, but in the specimens examined there .appears to be a short median septum in the pedicle-\'alve, and
no (-ardinal process in the brachial valve. It may prove necessary to separate this and the T. primordialis
of Whiti-'IELD, from this genus. The T. lateralis, Whitfield, fi'om the Fort C.assin beds (Calciferous sand-
stone), contains a spoon-shaped process in each valve, that in the pedicle-valve being supported by a med-
ian septum. It therefoi-e becomes necessary to remove this form to a distinct jjenus, and to a different
association and it will be descriV>ed and ilhisti-ated in its proper place under the name Stntrophia.

1 Aftei- becoming- acquainted with the internal characters of Trljilccia extans, which at that d.ite had
not been maile public, Mr. Mkbk withdrew this generic tei-m.

I See Silui-ian Supplement, pp. 114-147, pi. viii, tigs. 24-32.

BRACHIOPODA. 271

plecia ?) apiculata and A. (T. ?) incerta, the cardinal area is remarkably high and
erect, and the median fold is on the pedicle-valve instead of on the brachial
valve, as in the typical species. Should these prove genuine Triplecias, the
reversal of the relative convexity of the valves will be an occurrence similar
to that observed in the species of Mimulus. The species Produda (T. ?) monili-
fera appears to be a normally symmetrical, or slightly unsymmetrical (see plate
XXV, fig. 5) Streptis, and the T. ? Graya, a form with an erect cardinal area
and a strongly radiate surface ornamentation. In one of these radiated species,
the Orthis spiriferoides, McCoy, from the Upper Llandeilo and Caradoc, the ex-
istence of the peculiar articulating apophyses of Triplegia has been demon-
strated. (See Plate XI a, figs. 10, 11.) This species was referred to Triplegia
with doubt by Mr. Davidson, but the certainty of its being congeneric with
T. extans in these important features, opens the genus for the present to the
reception of similar radiated shells. Another excellent representative of this
type of structure is the Orthisina cava, Barrande,* from the Etage D...

Leaving out of consideration the Camarella calcifera, Billings, and the Triple-
da primordialis, Whitfield, the earliest known representative of this genus in
American faunas, appears to have been such a radiated form, T. radiata, Whit-
field, from the Calciferous fauna at Beekmantown, N. Y. In the fauna of the
Trenton group are T. extans, T. cuspidata and T. ?mcleus ; the only other member
of the genus known in this country being the T. Ortoni, from the Clinton fauna
of Ohio.

' SystSme Silurien du Centre de la Boheme, vol. v, pi. 59, fi-js. iv, 1-7.

272 PALEONTOLOGY OF NEW YORK.

Genus MIMULUS, Barrandk. 1879.

PLATE Xlc , FIGS. 23-32.

1878. Spiriftra{f), Miller and Dyer. JouriKil Cim-innati Soc. Nat. Hist., vol. i, p. 37, pi. ii, fig. 3.

1879. Triplegia, Hall. Trans. Albany Institute, vol. x. Abstract, p. 16.

1879. Mhiiulus, IJarrandb. Systeme Silui-ien du Centime de la Boh6me, vol. v, ]>. 109, pi. 1, fig-, iii ;

pi. 9, tigs, iii, iv, vi.
1882. jfripZiis'/a, Hall. Eleventh Ann. Rept. State Geologist of Indiana, p. 298, pi. xxvii, tigs. 19-22.
1889. Streptui, Beechbr and Clarkes. Memoirs N.Y. State Mnsenm. vol. i. No. i, p. 30, pi. iii, figs. 9, 10.

The affinities of this peculiar group of fossils have not hitherto been cor-
rectly understood. M. Barranue has given no clue to tlie interior characters
of tlie shells, and as the genus has been recognized only in the Bohemian basin
it has not been closely studied by other authors.* After a careful comparison
of M. Barrande's figures of the Bohemian species with the fossil known as
Triplesia pu'illus, Hall, or Spirifera Waldronensis, Miller and Dyer, from the Niagara
fauna of Indiana, there remains little doubt of their being congeneric forms.

The DIAGNOSIS of the genus, given by M. Barrande, is in the following
terms :

" Cette forme extt'rieure est coraplMement inverse de celle de Spirifer, en ce
que le bourrelet, bien marque, se trouve sur la valve ventrale, tandisque le sinus
correspondant se montre sur la valve dorsale.

" La charniere est droite, mais n'occupe pas toute la largeur du fossile. L'an'-a
bien developpre presente sous le crochet une ouverture triangulaire, fermee par
un deltidium, jusqu'au crochet. Celui-ci parait conserver un petit tron rond,
que nous observons sur un spt'-cimen non figure.

" II est rare de pouvoir observer le deltidium, parceque la trace de la soudre
avec I'area est completement efface.

" Les 2 especes typiques, Mim. perversus et Mim. moera, PI. 9, presentent exac-
tement les caractrres, que nous venous d'exposer."

The exterior form of these shells is subtrihedral like Triplegia, and is
subject to some variation, for of the three species described by M. Barrande,
two, M. perversus and M. moera, have the strong median fold on the pedicle-

' ZrrTEL (Handbiu-h dei' Paheontologie, vol. i, j). 684) made it a sub-genus of Spiriper, .and CEiilbrt
(Fischer's Manuel de Coueliyliologie ; Br.achiopodes, \>. 1313) placed it with doubt un<ler the family Hhyn-

CHoyKl.r.ID K.

BRACHIOPODA. 273

valve, while the otlier, M. contrarius, has it on the brachial valve. Again, all
the Bohemian species appear to be bilaterally symmetrical shells, while the
American Mimulus Waldronmsis, which has the fold on the brachial valve, is
always unsymmetrical in its mature condition, and may thus bear pretty much
the same relation to M. contrarius as Streptis does to TriplkciA;

A most striking feature in these shells is the character of the cardinal area,
which usually in Bohemian species, and invariably in the American form, is
smooth and without any superficial evidence of the delthyrium. In fact this
opening is closed by a thin flat jihxte, which may be sometimes broken away or
be absent from other causes, as appears from some of Barranue's figures.* It
has been shownf that in a very early growth-stage in M. Waldronensis the del-
thyrium is open and its apical termination circular. While the delthyrium
becomes closed, apparently by lateral accretion to the walls of the fissure, this
foramen is retained until maturity.:}: In the interior of this valve in M.
Waldronensis there are no dental lamellae, in which respect the genus differs
from Triplegia. Tlie l^rachial valve bears an erect, deeply bifurcated cardinal
process, of quite similar character to that in Triplecia extans. The other interior
features of Mimulus are still unknown, but those described are sutficient to
demonstrate the close alliance of these shells with the streptorhynchoids. All
the Bohemian species are from the Etage E_,, which is the equivalent of the
Niagara fauna.

* See Babrande, pL 9, figs, iv, E, g.

t Beecher and Clarke, op. cit.

X It will be observed that in Triplegia, Streptis and Mekkella, the median convex I'idg-e of the delti-
dium is very narrow, occupying- but a small part of the area between the dental plates. Tlie obliteration
of this low ridge would show a character similar to that of the deltidium in Mimdlus.

274 PALEONTOLOGY OF NEW YORK.

Genus STREPTIS, Davidson. 1881.

PLATE XI c, FIGS. 3:1-3!),

1848. TcrehraUda, Davidson. Bull. Soc. Geol. de France, tiiui .ser., torn, v, p. '■VA\. pi. iii, Hy. 33.

1859. Rhynchonella, Salter. In Murchison's Silurla, p. 2.")0.

1800. Spiriga-hia?, Lindstrom. Gotland's Bi-achiopoder, p. 364.

1SH7. Atrijpaf, Davidson. British Silurian Bi-achiopoda, p. 141, pi. xiii, tig-s. 14-22.

1879. Atrypaf, Barrandb. Systeme Silurien du Centi-e de la Boherae, vol. v, jil. 83.

1881. Streptis, Davidson. Geological Magazine, vol. viii, p. IfiO, pi. v, fig. 13.

1883. Streptis, Davidson. British Silurian Brachiojioda, Supjil., p. 39.

From what is known of tlie single species of this genus, S. Grayi, from the
Wenlock limestone, it would appear that its internal characters are essentially
similar to those of Tkiplecia. Mr. Davidson says that he was unable to deter-
mine the precise character of the cardinal process, but an imperfect interior,
illustrated upon plate xiii, tig. 21, of his Silurian Monograph, shows that it was
erect, though it appears to have been broken at the point of bifurcation ; the
short spiniform crura are also very distinctly seen, and upon careful examina-
tion of the specimens short dental plates can be seen in the pedicle-valve.
The exterior of the shell, however, is very peculiar in its bilateral asymmetry,
the existence of a sinus on each valve, and in the broad free frills at the con-
centric growth-lines.* In respect to its asymmetry the species, as already
observed, bears very much the same relation to Triplegia as the Mimulus Wald-
ronensis, from the Niagara fauna in Indiana, does to typical forms of the genus
Mimulus. The combination of these features with the surface ornamentation,
and the very small size of the species, will form a valid ground for the recogni-
tion of Streptis as a group subordinate to Triplegia.

* This feature is more extravagantly developed in the Bohemian species accoi-ding to the figures given
by B.VRKANDK (Systfeme Silurien, vol. v, pi. S3, figs. 2, 3a, 3d), than in the Engli.sh forms figured by David-
.soN. The Bohemian specimens are from Etage E^.

BRACHIOPODA.

275

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276 PALEONTOLOGY OF NEW YORK.

Genus L E P T ^ N A. , Dalman. 1 828.

PLATE Vin, FIGS. 12-31; AND PLATE XV A, FIGS. 4U-i:i.

1769. Conchites, Wilckbns. Nauhricht von seltenen Verstein., p. 77, pi. viii, figs. 43, 44.

1821. Anomites, Wahlenberg. Nova Acta See. Sci. Upsalse, vol. viii, p. 65.

1823. Product a, Sowerbt. Mineral Conchology, p. 86, pi. cccclix, fig-. 3.

1826. Broducta, Hisingkk. Acta Acad. Sci. Holm, p. 333.

182S. Lej3tana,V>k\Mkii. Upp.stallning och Beskrifning af <le i Sverige fiinne Terebratulitei- ; KiPiigl.

Vefen.skaps-AcademieiiH Handlingai-, tor ar 1827, pp. 94-96, 106, 1117,

pi. i, tigs. 1, 2.

1S34. Lcptwna, Klodbn. Die Vei-stein. der Mark Braudeiibiirg, p. ISO.

1837. Orthis. von Bdch. Ueber Delthyris oder Spirifer und Orthis, p. 30.

1837. Leptwna, Hisingbr. Lethjea Suecica, p. 69, pi. xx, tigs. 2, 3.

1837. £ep^a;«a,_FiscHER de Waldiieim. Oryctogr. du Gouv. de Moscou, p. 143.

1839. LepUena, J. de C. Sowerby. In Murchison's Silurian System, pp. 623, 636, pi. xii, tig. 2.

1840. Orthis, von Eichwald. Silurische Scbichten-System von Esthland, p. 162.

1841. Leptceiia, Phillip.s. Palteoz. Foss. Cornwall, Devon and West Somerset, p. 51, pi xxiv, fig. 9.').

1841. jStroplnniwJia, Conhad. Fifth Ann. Rept. N. Y. Geological Survey, p. 54.

1842. Ltptwna, de Koninck. Descr. Anim. Foss. dans le Terr. Carbonif. Belgi(pie.

1842. StntplunmnM, Vanuxbm. Geology of N. V. ; Rept. Third Dist., pp. 79, 139, tig. 53.

1843. Strophmntna, Hall. Geology of N. Y. ; Rept. Fourth District, pp. 77, 104, tig. 52 ; p. 175, tig. 3.

1843. Prod actus?, de Castelnai'. Essai sur le Systfeme Silurien de I'Amcrique Septentrionale, p. 39,

pi. xiii, fig. 7.

1844. Orthis, V. Rcemer. Das Rhein. Uebei-gangseebirge, pp. 85, 90.

1844. Lffptagimia, McCoy. Synopsis Carl). Foss. Ii-eland, p. 116.

1845. LeptcBiia. de Verneuil. Gcol. Russie de I'Eurojie et des Mont, de I'Oural, p. 234, pi. xv. fig. 7.

1846. Leptctiia, King. Annals and Magazine Natural History, vol. xvii, pp. 28, 36.

1847. Leptwna, Davidson. London Geological Journal, p. 54, pi. xii, tigs. 12-16.

1847. LeptceiM, Hall. Palfeontology of N. Y., vol. i, p. IDS, pi. xxxi A, tig. 4.

1848. Leptcemi. Davidson. Bull. Soc. Geol. de France, Ser. 2, vol. v, p. 306, pi. iii, tig. 3.
1848. Produclus, Davidson. Bull. Soc. Geol. de Fi-ance, Ser. 2, vol. v, p. 315, \A. iii, tig. 1.
1850. Leptwna, King. Monograph Permian Fossils of Englauil, pp. 81, 104.

1S52. Leptwna, Hall. Paleontology of N. Y. , vol. ii, pp. 62, 257, pi. xxi, fig. S ; pi. liii, tig. 6.

1856. Stnrphomena, Billings. Canadian Nat. and Geol., vol. i, p. 59, pi. i, fig. 5.

1857. Strophcmuna, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. S.'i.
1859. Leptwna, von Eichwald. Lethaea Ro.-^sica, vol. i, p. 867.

1859. Leptwna, Hall. Twelfth Rept. N. Y'. State Cab. Nat. Hist., p. 82.

1859. fitrophomena. Hall. Paljeontology of N.Y., vol. iii, p. 195, pi. xix, tig. 1 ; p. 417, pi. xciv. tigs. 2, 3.

1860. IStrophomena, F. Rosmbr. Silurische Fauna westlichen Tennessee, p. 66, pi. v, tig. 2.

1861. iStrophome7M, Billings. Canadian Journal, vol. vi, p. 336, tigs. Ill, 112.
1863. Slroplunnena, Billings. Geology of Canada, p. 311, fig. 314 ; p. 367, tig. 373.
1863. t^itropkomena, Billings. Proc. Portland Soc. Nat. Hist., p. 107. pi. iii, tig. 1.
1865. Leptwna, Shalbr. Bull. No. 4, Mns. Comp. Zool., p. 65.

1867. Strophomma, Hall. Pal.-eontology N.Y., vol. iv, p. 76, pi. xii, tig. 16-18; p. 414, pi. xv, tigs. 15, 16.

1868. IStroplwmeim, Meek and Wortukn. Geology of Illinois, vol. iii, p. 426. pi. x, tig. 7.

1873. i^troptioincna, Meek. Palaeontology of Ohio, vol. i, p. 75, pi. v, tig. tj.

1874. HtntpliomeiM, Billings. Palceozoic Fossils, vol. ii, p. 27.

1874. ^trophomeiM, Jambs. Cincinnati Quart. Jour. Sci., vol. i, p. 333.

187.'". IStropliomena, Mili.kr. Cincinnati Quart. Jour. Sci., vol. ii, p. 55.

BRACHIOPODA. 277

1875. Strophomena, Wiiiru. Geojri'uphical and Geolojrical Kxploi-alidn West lOOtli Mcriiliaii, p. S5,

pi. V, fig. 5.

1S77. Strop/Mmeim, Hall and Whitfield. Geol. Expl. 4flth Parallel, vol. iv, p. 2r)3, pi. iv, fig'. 4.

1877. Plectamhnmteji, D.\ll. Bnll. No. 8, U. S. Nat. Mnsenm, p. SC.

1879. Strophimiena, Hall. Twenty-eig-hth Repf. N.Y. State Mns. Nat. Hi.st,, ji. 151, pi. xxii, tigs 4-10.

1SS2. Strophomena, Hall. Eleventh Rept. Indiana State GeologiKt, p. 288, pi. xxii, figs 4-10.

1883. Strophovuna, Hall. Rept. N. Y. State Geologist for 1S82, pi. xxxviii, figs. 12-31.

1884. Strophomena, Walcott. Palaeontology Eureka District, p. 118.

1887. Plectambonites, QEhlert. Fischer's Manuel de Conchyliologie ; Brachiojioda, p. 1285.

1889. StropliomeiM, Bekcher and Clarke. Mem. N. Y. State Mus. Nat. Hist., vol. i. No. 1, p. IS, iil. ii,

figs. 1-13.
1889. Strophomena, Nettblboth. Kentucky Fossil Shells, p. l.'iO, pi. xviii, figs. 1-3.

Diagnosis :

" Testa subgequivalvis, aequilatera, complanata, margine compresso flexo.
" Margo cardinalis transversalis, rectilineus, latissimus, foramine destitutu^.
" Valva altera deiitibus cardinalibus duobus obtusis." — Dalman, op cit., p. 94.

Shells plano-convex when young, concavo-convex at maturity ; convexity
normal. Surface covered by conspicuous concentric corrugations or wrinkles
over the flatter portions of the valves. Where these cease the surface is more
or less abruptly and often rectangularly deflected, forming a conspicuous an-
terior slope. The whole exterior is covered with fine, even, radiating, thread-
like, tubular stria3, which, in well preserved specimens, are crenulated by finer
concentric strise. Outline transversely subquadrate or semioval. Hinge-line
straight, its length making the greatest diameter of the shell ; extremities often
subauriculate. Cardinal area narrow, slightly wider on the pedicle-valve, not
denticulate. In the pedicle-valve, the delthyrium is covered by a convex
deltidium, perforated at the apex by a foramen whicli is closed at maturity or
encroaches upon the apex of the valve. This deltidium is most conspicuously
developed in early stages of growth, then having the form of a tube or
sheath, which character becomes obliterated as maturity approaches, by the
increase in the size of the cardinal process of the opposite valve, and the cal-
losity formed about its base. In adult shells the foramen has become enclosed
by the substance of the shell, its external opening being an oblique gi'oove in
front of the apex of the valve, and its inner aperture appearing in front of the
pedicle-scar. Not infrequently the passage is closed at maturity. The teeth
are very divergent and quite consjiicuous, generally supported by lamellae

278 PALEONTOLOGY OF NEW YORK.

which are continued around the subcircular muscular area of the narrow um-
bonal cavity. The muscular scars consist of a narrow median or adductor,
enclosed by flabclliform diductors.

In the brachial valve the area is linear, the delthyrium is progressively filled
by the growth of a callosity, which is often deeply grooved along the center, and
sometimes perforated in the line of division between the branches of the cardinal
process. The cardinal process consists of two sessile, diverging apophyses which
have broad, flat, striated surfaces of attachment, and are extended beyond the
hinge-line. The sockets are moderately deep ; the crural plates are usually not
sharply defined, but are continued in a curving line along the inner surface of
the valve, partially embracing a pair of broad, ovate muscular impressions
which are marked by arborescent ramifications ; recurving and again incurv-
ing, these ridges partially surround a pair of smaller muscular areas, lying in
front of the first. At the inner base of each branch of the cardinal process
there arises a low elevation or callosity, which, extending obliquely forward,
and uniting in the center, continues as a narrow median ridge dividing the
posterior pair of muscular impressions. This ridge sometimes terminates in a
point near the base of the first pair of impressions, and the second' pair are
separated by a low, slender median septum, which sometimes apparently takes
its origin at this point, but which is in fact a continuation from the interrupted
posterior ridge, and extends for some distance over the pallial region.

The muscular area, when its fesitures are most distinctly retained, shows a
subdivision into the following scars : (a) A large posterior pair (the posterior
adductors), the surface of which is covered with arborescent ridges ; the ante-
rior portion of each of these scars is smoother than the rest, generally much
thickened and often extremely elevated at its outer margins. These may
be regarded as accessory elements of the posterior adductors. (6) An anterior
pair (anterior adductors), situated close together at about the center of the
valve. The position of these is generally well defined but their outline is fre-
quently obscure, (c) An elongate, narrow median scar, which is apparently
divided for its entire length by a faint ridge. In front of the muscular area
there are often a number of short protuberances on each side of the median

BRACHIOPODA.

279

Fig. 18. LrptiFiiti rhomhoUlnlUt
re-ssioiisorsj)!!
I'V r>.v\'ii>soN".

.septum, and the anterior pair of scars is frequently obliterated by prominent
callosities. At the line of geniculation the interior sur-
face is elevated into a very prominent, sharp, or abruptly
rounded crest. Spiral callosities for the support of the
brachia, similar to those in Daviusonia and LeptvENIsca,
have been observed by Dr. Davidson.

Shell-substance strongly punctate.

Type, Leptana rugosa, Balmnn = Producia rugosa, His- .„„wi„ffinM.re,ssionsor»,>,™uum.
mger=Conchites rhomboidalis, Wilckens. Upper Silurian.

Observations. Having already given at some length the reasons tor restricting
the application of the term Strophomena, Rafinesque, as defined and illustrated
by DE Blainville, the genus Lept^ena, of Dalman, will be left to rest upon its
first and typical species, Produda rugosa, Hisinger. This is precisely the interpre-
tation of the genus followed by most authors from 1830 to 1860 Prof. King,
in the Annals and Magazine of Natural History, 1846, and in his Monograph
of the Permian Fossils of England, 1850, proposed restricting the genus more
narrowly than heretofore, including only "such shells as L. analoga, Phill., L.
semiovalis, McCoy, L. plicotis, McCoy, L. nodulosa, Phill., and L. muUirugata,
McCoy" (Permian Fossils, p. 104). All these are of the type of L. rhnm-
bnidalis. During the early part of this period Strophomena, as already pointed
out in the discussion of that genus, was a term of uncertain value.

Dalman placed under his genus Lept^na four species, in the following order:
L. rugosa, Hisinger, L. depressa, Sowerby, L. eughjpha, Dalman, L. transversalis,
Wahlenberg. The same author observed that the first two of these had been
included by Wahlenberg, in 1821, under the name Anomites rhomboidalis, this
specific term having been first used by Wilckens, in 1V69. The other two
species are not congeneric with L. rhomboidalis. Davidson, however, regarding
the first three as proper Strophoinenas (1853-1884), decided to take the last
species, L. transversalis, as the type of Lept^na, and it is this use of the term
that has become current among palaeontologists. Were it necessary, however,
to reject the first two of Dalman's species, the third, L. eughjpha, a member of
the genus Strophonella, Hall, 1879, would have to stand as the type of Lep-

280 PALAEONTOLOGY OF NEW YORK.

T/ENA. In 1844, McCoy, having proposed to apply the term Lept^ena to species
of Productus or Chonetes or both, suggested a new term, Leptagonia, for shells
like Produda analoga, Phillips = Leptcena rhomboidalis*

There are sufficient reasons for limiting the application of the term LEPTyKNA
to shells conforming precisely to the structure exhibited by L. rhomboidalis.
Dr. Davidson, in his later years, was evidently convinced of the validity of
this group.f Whether L. rhomboidalis shall be allowed to include all the forms
from Silurian to Carboniferous faunas which have the characters given in the
foregoing diagnosis, or whetlier the numerous specific and varietal names that
have been proposed shall be recognized in whole or part will depend upon one's
conception of specific values. At all events the type of intern.al structure
accompanied by the peculiar corrugated and geniculated exterior has proved a
very compact and resistant combination, a fact evinced by the mere possibility
of a question arising as to the specific identity of the various forms. It is
worthy of note that among the American representatives of this type of struc-
ture which have been studied, the extreme differentiation of the muscular area
as described is even more distinctly exhibited in the forms of the early Car-
boniferous than in those of the Silurian and Devonian.

Believing that it will serve a good purpose in the taxonomy of these organ-
isms to thus restrict the generic term Lept^.na to this peculiar gi'oup of forms,
it will become necessary to arrange under another designation the much more
abundantly developed " Strophomenas " of the Silurian, exemplified hy Lep-
tana alternata of Conrad. These differ essentially from L. rhomboidalis, not in
their exterior features alone, but also in their interior characteristics ; and there
is no name among all those which have been suggested or superceded which is
applicable, or can be legitimately used, and therefore it becomes necessary to
propose a new generic term.

* De Vernedil, in 1845, proposed a classification of the species then referred to this genus, on the basis
of their superficial tirnaminitation. His conception of tlie g-eniis is expre.s.sed in his own words : " Nous
proposona de rendro au g'eni-e Lkpt^na, sa valeur piimitive, en y reunissant toutes les coquilles jilus ou
moiii.«i analogues a celles (jue Dalman avait ainsi nommees" (Geologie de la Russie, etc., p. 215). We thei-e-
fore find in his list of twenty-thiee species not only the various types of .structure given by Dalman, but
some othei's.

t See General Summary, p. 'Xi'^.

BRACHIOPODA. 281

Genus 11 A F I N E S Q U I N A, gen. nov.
LfiPiMiNA ;uid Strophomena of most authors.

PLATE VIII, FIGS. 1-U ; PI-.ATE IXa, FIGS. 1, i, 4; AM) PLATE XVa, FIGS. '(7, .M, ffl(?|.

1838. Leptcena, Conkad. Second Ann. Rept. N. Y. Geolog-ical Survey, p. 1 ir>.

1839. Strophomena, Conrad. Third Ann. Rept. N. Y. Geoloffical Survey, pp. 03, 61.

1840. Sti-oplurinena, Conkad. Fourth Ann. Rept. N. Y. Geological Survey, p. 201.

1841. Stropkmntna, Conrad. Fifth Ann. Rept. N. Y. Geological Survey, p. 37.

1842. Strop}i(»nena, Conrad. Jour. Acad. Nat. Sci. Phil., vol. vnii. p. 254, pi. xiv, fig-. ."> ; pp. 2,")9, 260.
1842. Stroplwiiitna, Va.noxkm. Geological Rdpt. Third Dist. N. Y., p. 46, tig. 2.

1842. strophomena, Emmons. Geol. Rept. Second Di.st. N.Y., p. 3S9, fig. 2 ; p. 395. fig. 3 ; p. 403, tig. 3.

1843. Orthiii, de Ca.stelnau. Essai sur le Systerae Silurien <le rAnicriciue .^eptontrionale, jjp. 37, 38,

pi. xiv, figs. 1, 6.

1844. Strophomena, Owen. Geol. Expl. Iowa, Wiscon.sin. and Illinoi.s, pi. xvi, fig. 8 ; pi. xvii, fig. 6.
1847. Leptmna, Hall. Paleontology of N. Y., vol. i, p. 19, pi. iv (bi.s), fig. 2 ; p. 20, pi. iv (bis), tig. 3 ;

p. 102, pi. xxxi, fig. 1, pi. xxxiA, tig. 1; pp. 106, 107, pi. xxxiA, figs. 2, 3;

p. 109, pi. xxxi B, fig. 1 ; p. 115, pi xxxi n, fig. 8 ; p. 286, pi. Ixxix, fig. 2.
1852. Lept^nn, Hall. Paleontology of N. Y., vol. ii, p. 62, pi. xxi. tig. 6.
1856. Strophomena, Billings. Canadian Nat. and Geol., vol. i, p. 214, tig.^. 3, 4.
IS.oS. Stroph'imena, Rooers. Geology of Pennsylvania, vol. ii, p. 817, fig. 591 ; p 818, tig. BOO.
1859. Strophomena, Hall. Twelfth Rept. N. Y. State Cab. Nat. Hist., p. 70.

1859. Stro2)homena, Billings. Canadian Nat. and Geol., vol. iv, p. 443.

1860. Strophomena, Billings. Canadian Nat ami Geo!., vol. v, pp. 51-54, tig. 1.

1862. Strophomena, Billi.vgs. Paleozoic Fossils, vol. i, pp. 117, 118, fig. 97; pp. 119, 128, fig. 106.

1863. Strophomena, Billings. Canadian Geology, Repoi-t of Progress, p. 163, fig. 140; pp. 141, 209.

fig. 208.

1865. Strophomena, Shaler. Bulletin Mns. Comp. Zoology, No. 4, p. 82.

1868. Strophomeiia, Meek and Worthen. Geological Survey of Illinois, vol. iii, p. 335, pi. iv, fig. 11.

1871. Strophomena, Davidson. British Silurian Brachiojioda, p. 285, pi. xlii, figs. 20, 21 ; p. 292, pi. xlii,

figs. 1-5 ; pi. xxxix, figs. 22-24 ; p. 296, pi. xxxvli, figs. 23-26 ; pi. xlii,
figs. 6-8 ; p. 383, pi. xfii, figs. IS, 19 ; i>l. xlvii, figs. 1-4 ; pp. 310. 311,
■pi. xlii, fig. 11 ; pi. xliii, fig. 15; p. 312, jil. xiv, tigs. 1-10.

1873. Strophomena, Meek. Paleontology of Ohio, vol. i, pp. 88-91, \>\. vii.

1874. Strophomena, Miller. Cincinnati Quart. Jour. Sci., vol. i, p. 13.

1874. Strophomena, James. Cincinnati Quart. Jour. Sci., vol i, p. 335.

1875. Strophomena, Miller. Cincinnati Quart. Jour. Sci., vol. ii, pp. 51-54.

1881. Strophmneiui, N. H. Winchell. Ninth Annual Rept. .State Geologist of Minnesota, p. 120.

1881. Strophomena, White. Tenth Ann. Rept. Indiana State Geol., p. 113, {)I. i, figs. 6, 7.

1882. Strophomena, Whitfield. Geology of Wisconsin, vol. iv, p. 261, pi. xii, figs. 15, 16 ; p. 262,

pi. xii, fig. 14.

1883. Strophomena, D.vvidson. British Silurian Br.achiopoda, Suppl., p. 193, pi. xvi, figs. 6, 7.
1883. Strophomena, Uxht.. Report N. Y. State Geologist for 1882, pi. xxxviii, figs. 1-11.
1887. Strophomena, Shaler. Memoii-s Kentucky Geol. Survey, p. 4, pis. ii, iii.

Diagnosis. Shells normally concavo-convex. Surface ornamented by radi-
ating striae, of alternating size, cros.sed and crenulated by finer concentric
striae. Cardinal margins without denticulations. Interior of the pedicle-valve

282

PALEONTOLOGY OF NEW YORK.

with the muscular area not strongly limited ; consisting of two broad flabel-
late diductor scars enclosing an elongate, more distinctly defined adductor.
The faintness of the limitation of this area is in marked contrast to the sharply
defined muscular area in the corresponding valve of Lept^na. In the brachial
valve the cardinal process is more closely sessile than in LePT/Ena, and there is
frequently a linear callosity between the branches. The posterior adductor
scars have the arborescent markings of Leptmna rhomboidalis, and these impres-
sions are the only ones well defined, the anterior scars being narrow and rarely
retained with distinctness. From the anterior margin of the muscular area
radiates a series of irregular furrows and nodose ridges, which are to some ex-
tent of vascular origin.

Type, Leptmia alternata, Conrad. Trenton and Hudson River groups.

Fit;. i;». Jiajinesquum Jukesi, showing the brachial riflgc.^.
After Davidson.

Observations. There are some shells, a small number of species however,
which combine to some extent the characters of both LepTjENA and Rafines-
QUiNA. We may instance Leptcena delloidea, Conrad, and Strophomena unicostata,
Meek and Worthen, in which there are not only low, concentric corrugations
on the exterior, but in the latter species the interior of the brachial valve
has more distinctly the impress of Lept^ena than of Rafinesquina. There
are concentrically wrinkled species in the genera Strophomena, Stropheodonta
and Strophonella, but that character will prove of little value except for a
subsidiary grouping of species. The extravagant development of this feature

BRACinOPODA.

2S3

in Leptcena rhomboidalis, persisting tliroughout so m.any successive faunas, forms
one of the substantial reasons for tlie separation of that form from its allies.

The leptsenoid type of structure attained its most abundant exemplification
in the fiiunas of the Silurian. Leptczna rhomboidalis, which appeared in the
Trenton and Caradoc has alone carried this type onward through the Upper
Silurian, the Devonian and into the Lower Carboniferous. Rafinesquina is
represented l.)y a number of species in American faunas, e.g., Leptana fasciata.
Hall, of the Chazy; L. allernata, Conrad, L. alternistriata. Hall, L. deltoideu, Con-
rad, Strophomena camerata, Conrad, and Leptana incrassata, (Hall) Safford, of tlie
Trenton ; S. Minnesotensis, N. H. Winchell, S. Kingi, Whitfield, S. nitens,
Billings, Leptczna allernata, Conrad, Strophomena squamula and S. Ulrichi, James,
from the Hudson River group.

In the Clinton fauna the Leptana obscura, Hall, may belong to this group, and
if so is probably its latest representative in our faunas. In the Silurians of
Great Britain the best developed representation of these fossils is in the Caradoc
fauna {Leptczna {Leptagonia) ungula, McCoy, L. deltoidea, Conrad, Strophomena
Jukesi, Davidson, S. Holli, Davidson, S. siluriana, Davidson, Orthis expansa, Sovv-
erby). There are a number of species in the Wenlock which appear to belong-
to this group, such as Orthis Orbigiii/i, Leptczna Waltoni and Strophomena Hender-
soni, Davidson.

Fiii. 20. Sii-ophomenn [Jin/iiK^'/uinti , Jnh\^i, Davidson.
Alter Davidson.

284 PALEONTOLOGY OF NEW YORK.

Genus STROPHEODONTA, Hall. 1852*

PLATE Xlll, FIGS. 1 ;;■•*; PLATE XIV. FIGS. 1--33; PL.VTE XV, FIGS. -2-21; and PLATE XVi!, FIGS 1-0.
1830. Pleetainbonites, Pander {partim). Beitr. zur Geognosie des russ. Reich., p. 91, pL xix. tit;. 12.
1838. Leplmia, Conk.\i>. Second Ann. Kept. N. Y. Geolog-ical Survey, pp. 112, 117.
1S39. OrtltU, Sowkkhy. Mui-chison's Silui-ian System, pL xiii, fig. 12 ; pL xxii, fig. 12.

1841. Orthis. Phillii-s. Palseoz. Foss. Cornwall, Devon and West Somerset, p. 61, iil. xxv, fig. 103.

1842. Stmpkomnia, Conkad Journ. Acad. Nat. Sci. Phila., vol. viii, pp. 254-259, pi. xiv, figs. 2, H, H,

7. 10, 11, 14, 19.

1842. ,Slrop//omena, Vanuxkm. Geology of N. Y. ; Kept. Third District, p. 174, fig. 1.

1843. ASIropliiiiiiemi, Hall. Geology of N. Y. ; Rept. Fourth District, p. 104, fig. 3: p. 171, fig. 4;

p. 200, fig. 4 ; p. 2eti, figs. 1, 5.
1845. UptaiiM, DK VniiNKiJii,. G6oI. Russ. et des Mont, de I'Oural, p. 220, pi. xiv, fig. 1 ; p. 223, pi. xiv,

fig. 2 ; p 224, pi. xiv, figs. 3, 4 ; p. 230, pi. xv. fig. 3.
184(i. lirtli'is. McCoy. Synopsis Silurian Fossils Ii-eland, p. 30.

1848 Lipimna, Davidson. Bull. Soc. Geol. de Fi-ance, Ser. 2, vol. v, p. 318, pi. iii, fig. 0.
1848. Oiihis, Stivp/iimieua, Phillips and Salter. Mem. Geological Surv. United Kingdom, vol. ii,

pp. 288, 379.
18.')2. Leptcena, >Sti-(>p?ii:udimta, Hall. PaU-eontology of N. Y.. vol. ii, pp. (il, 63, pi. xxi, figs. 4, 5, 3.;

J). 327, pi. Ixxiv, fig. 6.

1852. tftnrphudonta, Owe.n. G('o1. Surv. Wisconsin, Iowa and Minnesota, pp. 584, 585.

1853. Leptmna, Schnuk. Besclir. Eit'el vorkomin. Brachiopoden, pp. 222-224, pi. xxxix. fig. 5; pl. xli,

figs. 1, 3, 6 ; pl. xlii, figs. 3, 4.

1857. ,Stropli<imeiia (f<trophodonta), Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 52-55, 111,

113-115, 137-145.

1858. t^trophomena, RoonRS. Geology of Pennsylvania, vol. ii, p. 837, figs. 665, 666.

18.58. Strophochmta, Hall. Geol. Surv. Iowa, vol. i, pt. ii, pp. 491-493, 495, 496, pl. iii, figs. 1-3, 5, 6.

1859. SlrophiKhnita, Hall. PaU-eontoIogy of N.Y., vol. iii, pp. 180-184, 191, 194, 411-415, 482, pl. viii,

figs. 2-16 ; pl. xvi, figs. 1-14 ; pl. xviii, tig. 1 ; pl. xxii. fig.l; pl. xcii,
figs. 2-4 ; pl. xciii, figs. 2-4; pl. xciv, figs. 2, 3; pl xcv, figs. 8-10;
pl. xcv A, figs. 13-19.

1860. Stniphodiinta, Swallow. Ti'ans. St. Louis Acad. Sci., vol. i, pp. 635-639.

1860. Strojihiidoiita, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 90.

1861. Stmpliomena, Billings. Canadian Journal, 2nd Ser., vol. vi, p. 338, fig. 113; p. 340, figs. 116-118 ;

pp. 341, 343, 344, 348, 349.

1863. Strophomena, Billings. Geology of Canada, p. 367, figs 374, 375. 377 ; p. 961, figs. 468. 469.

1863. Stropliodmita. Hall. Sixteenth Rept. N. Y. State Cab. Nat. Hist , pp. 36, 37.

1863. SIriiphometia, Billings. Proc. Poi-tland Soc. Nat. Hist., p. 109. pl. iii, fig. 3.

1865. SIrojyhomena, Billings. Palsozoic Fossil.s, vol. i, pp. 120, 122, figs. 98-101.

1865. Li'pl(p,na, Davidson. British Devonian Brachiopoda, p. 85, pl. xviii, figs. 15-18.

1865. lSlrophtmi,eiia. Winchell and Marcy. Memoirs Boston Soc. Nat. Hist., vol. i, p. 92, jil. ii, fig. 9.

1865. Strophodonta, Mbbk. American Journal Science, vol. xl, p. 33.

1866. Strophodonta, Winchki.l. Rept. Lower Penin. Michigan, p. 93.

1867. Strophoilonliu Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist., p. 369, pl. xiii, fig. 34.

1867. fS't.r<ipl,iid(,iUn. Hall. Paheontology N.Y., vol. iv, pp. 81-93, 96-111, 113, 114, pis. xi; xii, figs. 1-15;

xiii; xiv, fig. 2; xv, figs. 1-14; xvi; xvii ; xviii; xix, figs.1-5, 8-19.

1868. ^irophodonta. Meek, Trans. Chicago Acad. Sci.. vol. i, pp 87, 88, jil. xiii, figs. 6, 7.

1871. iStropliomejia, David.son. British Silurian Brachiojioda, pp. 286, 307, 309, 315, pl. xli, figs. 1-6;

pl. xliii, figs 16-20 ; pi. xlvi, figs. 7-10.

* Stropmeodonta, "Gr. aTpo<pevg; Mirdo, and odovj", deux." This tei-ni has come into general use
with the form Sthophodonta, which has a diflerent etymology. It may be well to adhere to the original
form of the word as more ai)iiropriate in its application to these shells.

BRACHIOPODA. 285

1871. StropJtomena, Katseb. Zeitschrift (ier (ioutsch. g:eolog. Gesellschaft, vol. xxiii, jip. (520,621,624,

62.'), 627. 630, i)l. xiv, figs. 4, 5.

1872. Strophmneim, Barrande. Systeme Siluiien dii Centre de la Bohfme, pi. xl, fig:*. 10-19 ; pi. xlii,

figs. 6-14, 21-28 ; pi. xliii, tigs. 1-5, 17-29 ; pi. xliv, figs. 1-30.

1873. Strophodmita, Hall ami Whitfield. Twentv-tbinl Kept. N. Y. State Cab. Nat. Hist., pp. 236,

239, pi. xi, figs. S-11.

1873. StropJiodoiita, Nicholson. Rapt. Palaeontology Province of Ontario, pp. 64, 65, 67.

1874. Strophomena, Billings. PalpEozoic Fossils, vol. ii, jip. 20, 24, 26-2!i.

1877. Strophodonia, Hall .ami Whitfield. King's Expl. and Siirv. Fortieth P.arallel, vol. iv, p. 246,

pi. iii, figs. 1-3.

1878. Strophodonta, Calvin. Bulletin No. 3, United States Geological Survey, vol. iv, jip. 727, 728.

1875. Strophodonta, Barrett. American Journal of Science vol. xv, p. 372.

1879. Strophodonta. Hall. Twenty-eighth Rept. N.Y. State Mtis. Nat. Hist., p. 151, pi. xxiii, figs. 9, 10.

1880. Strophomena, Dawson. Canadian Naturalist and Geologist, 2nd Ser.. vol. ix, p. 341.

1881. Strophodonta, White. Tenth Rept. Indiana State Geologist, p. 132, pi. iv, figs. 6, 7.

1881. Strophomena, Davidson. Brachiopoda Bndleigh-Salferton Pebble-bed, pp. 348-351, pi. xxxix,

figs. 1, 2, 4-11.

1882. Strophodonta, Hall. Eleventh Ann. Rept. State Geologist Indiaini, p. 289, pi. xxiii, figs. 9, 10;

pi. xxvii, tig. 18.

1882. StropJiodimta, Whitfield. Geology of Wisconsin, vol. iv, p. 327, pi. xxv, fig. 18.

1883. Strophodo7ita. Hall. Ann. Rept. N. Y. State Geologist for 1882, pis. xiii (44) ; xiv (45) ; xv (46),

figs. 1-24.

1884. Strophodonta, Walcott. Paleontology Eureka Dist., pp. 118-122, pis. ii, xi, xiii.
1889. Strophodonta, Nettelrot'h. Kentucky Fossil Shells, ]ip. 142-150.

1889. Strophomena, Bakrois. Faune du Calcaire d'Erbi'ay, pp. 63-65, 67, \A. iv, figs. 6, 8-10.

Diagnosis. Shells normally concavo-convex or .subplano-convex. Cardinal
area common to the two valves, that of the brachial valve narrower or linear ;
smooth or finely striated longitudinally, sometimes showing through the outer
laminse of the shell strong, parallel, transverse bars, which project beyond the
cardinal margin as short processes, and articulate with a corresponding series
of pits in the opposite valve. The earliest species have these denticulations
developed only for a short distance on each side of the center, while in the lat-
ter faunas they extend the entire length of the hinge-line. In the type-species
the delthyrium is usually completely closed by the extension of the shelly laminte
of the area, and on the inside by the formation of a callosity between the
apophyses of the cardinal process. Sometimes a low, narrow, convex deltidium
is present, but in the early species the delthyrium is frequently open.

From the normal position of the dental lamellae there extend two diverging,
sometimes nearly vertical, ridges of variable strength, bounding the post-lateral
portion of the muscular area, which is not limited by a ridge in front. The
entire muscular area consists of two broad flabelliform diductor scars, enclosing
an oval adductor which is distinctly divided into anterior and posterior ele-

286 PALEONTOLOGY OF NEW YORK.

ments. The foramen, dental plates and teeth are obsolete or obsolescent in the
Devonian species.*

In the brachial valve the delthyrium is also usually closed ; the cardinal
apophyses are strongly arched into the uinbonal cavity of the opposite valve,
their surfaces of attachment being sometimes nearly parallel to the plane of
the cardinal area of the brachial valve, and often extending beyond it. Small
crural plates are always present, though they could not liave been functional
at maturity. Muscular arrangement similar to that of Leptczna rhomboidalis and
Rafinesquina alternata, the posterior scars being more elongate, the anterior pair
usually less defined, and all the scars frequently obscured. The anterior
muscular fulcra are sometimes developed into very prominent elongate apo-
physes. The median septum often becomes elevated into a high crest at the
center of the valve. Over the pallial region the interior of both valves is
strongly papillose. External surface covered with radiating, sometimes fas-
ciculate strise; rarely smooth. Shell-substance fibrous, coarsely punctate.

Type, LepliZna demissa, Conrad. Hamilton group.

Observations. The distinctive characters of this genus are clearly evident,
but notwithstanding its importance, both zoologically and geologically, it has
never been accorded general recognition except among American writers. Mr.
Billings would not admit its validity ; Dr. Davidson barely noticed the terra ;
Professor Kayser and tlie German writers generally continue to refer its species
to Strophomena (= Strophomena, Lept^na, Rafinesquina, etc.) ; Dr. CEhlert
has adopted it, making it a sub-genus of Strophomena, Rafinesque (de Blain-
ville), while he proposes a new genus, Douvillina, which is essentially synony-
mous. The genus Stropheodonta is a large one, being represented in American
faunas by not less than fifty species, and it is emphatically characteristic of the
Devonian. It makes its first appearance in the Clinton group, having a sparse
representation in the Niagara, but becomes more abundant in the Lower

* The obliteration of these parts may be due to the excessive secretion of calcaieous matter in the uni-
l)onal region. Where this deimsit is less there remains some evidence of these features, as in S. profunda of
the Niagara, )S'. lievki of the Lower Helderbei-g, and esijecially in xS. magnifica of the Oriskany sandstone,
one of the largest species of the genus, in which the short dental lamelliE convei-geand unite at the bottom
of the rostral cavity, making a soi-t of pediclo-jiit and leaving thc> dcllliyrium open. See Plate XIII, tig. 28.

BRACHIOPODA. 287

Helderberg, Oriskany and throughout the Devonian, disappearing witli the
fiiuna of the Chemung group.

The Stropheodontas comprise two natural subdivisions based on the contour
of the shells alone. The typical group is strongly concavo-convex, and to this
belong the majority of the species which can be referred to the genus in its
widest scope. Subordinate to this group of convex forms is a smaller division,
exemplified by S. nacrea. Hall, of the Corniferous and Hamilton faunas, in which
the surface is smooth, often nacreous and with a few squamous growth-lines.
The entire substance of the shell is strongly punctate, the epidermal impunctate
layer, which in other species preserves its usual thickness, seems here reduced
to a mere film. The interior of the brachial valve bears three divergine;
ridges in front of the muscular area, in this respect resembling Leptcena rhom-
boidalis more than typical Stropheodonta. Closely allied to the species is
Strophomena lepis, Bronn, of the Middle Devonian of the Eifel, Belgium and the
Asturias.* It may be found convenient to unite these and an unnamed species
from the Corniferous limestone under the term Pholidostrophia.

The plano-convex species of Stropheodonta are distinguished from the group
of S. demissa by more than contour alone. The characters of the deltidium
show the same progressive development as in the concavo-convex Strophe-
odontas, the earliest species having the delthyrium sometimes open, sometimes
partially closed by a convex plate; while in the Devonian species the deltidium
is reduced to a flat, transverse lamina, supported within by the callosity about
the cardinal apophyses. In the pedicle-valve are two very strongly pustulose,
diverging ridges, bounding the muscular impressions on their lateral margins,
while anteriorly these scars are broadly flabelliform and not strongly limited.
Tlie central adductors are small, relatively obscure and not divisible.! Should

* Dr. (Ehlbbt associates with S. lepis, Bronn, and *S. JSarajuana, de Verneuil ( =S. lepis, Bionn, teste
Kayskr), the finely striated species S. clausa, de Verneuil, and S. Leblanci, Rouault. This group, he says,
forms a passage to the family Prodvctidjb, in the rudimentary condition or absence of the foramen, the
obsolescence of the teeth and sockets, the arrangement of the muscles, and especially, in the existence of
reniform impressions (Ann. des Sciences Geologique, vol. xiv. Art. No. 1, p. 63, 1887. See pi. iv, fig. 10).
Kayser has obsei-ved a similar structure in the Leplmna caudata, Schnur, of the Eifel (Zeitschi-. iler deut-sch.
geol. Gesellsch., vol. xxi, p. 628).

t (S. Calvini, Millei-, and «*?. Canace, Hall and Wiiitfield, are convex shells with the interior characters
of this group. Neither their external nor internal features are very positively developed, and these shells
ai-e excellent examples of connecting forms.

288 PALEONTOLOGY OF NEW YORK.

it be found desirable or important to recognize the value of the characters above
indicated, these forms may be separated under the term Leptostrophia.

As typical representatives of this group, may be taken S. magnifica, Hall, of
the Oriskany sandstone, and S. perplana, Conrad, of the Corniferous, Hamilton
and Chemung faunas ; and of the other American representatives we may cite
S. textilis, Hall, of the Coralline limestone, S. Becki, Hall, of the Lower Helder-
berg, S. magniventra, Hall, of the Oriskany, S. Jmia, Hall, of the Hamilton, S.
Irene, S. BlainviUii and S. Tullia, Billings, from the Lower Devonian of Gaspe.
In European fiiunas the group is represented by Strophomena filosa, (Sowerby)
Davidson, of the Wenlock, S. explanata, (Sowerby) Kayser, of the Coblenzian,
S. ? palma, Kayser, of the Calceola beds, and S. Steini, Kayser, of the Wiedaer-
schiefer (Lower Devonian) of the Hartz

There is a small number of species, the incipient members of the genus
Stropheodonta, in which the delthyrium is open, or but partially covered, as
in some of its later forms, the crenulations are confined to a very limited ex-
tent on either side of the deltidium, and upon one of these forms, Strophomena
Leda, Billings, from the Anticosti group, Professor
Shaler has proposed to found* the genus Brachyprion.
To the same group belong the Strophomena. Philomela,
Billings, from the Pentamerus oblongus beds of Anticosti,
and Professor Shaler has described two other species
from Anticosti, Brachyprion ventricosum and B. genicula- Fu;.i\. nrm-h,n,riou im,,.

, , 1 T f After BiLLiNUS.

turn. These features can scarcely be i-egarded as oi

•generic value, but the group is an interesting one on account of its being the
precursor of the fuller development of those characters on which the genus
Stropheodonta was originally founded.

Dr. CEhlert has proposed the generic term Douvillina,! for the species
Leptana Duteririi, Murchison,|: evidently not fully apprehending its very close

* Bulletin of the Museum of Comparative Zoology, vol. i, p. 63. 1865.

t In Fischer's Manuel de Conchyliologie ; Brachio))odeH, p. 1282. 1887.

\ See DK Veknhuil, Geolo^ie ile la Russie, etc., p. 223, j)l. xiv, figs. 2 a, b, c. Fig. 4 of the same plate
repre.sents an interior clo.sely .similar to that figured by (Eiilert, and in the explanation of plate is referred
to L. Duteii,rii, but on page 224 is regarded as belonging to L. asella, de VernHuil. In this case the latter

BRACHIOPODA. 289

relationship to, or identity with Stropiieodonta. In his diagnosis of the genus
he describes the shell as having a crenulated hinge and Hat deltidiuin. In
the pedicle-valve are two small teeth connected with diverging i-id"-es
which are strongly elevated in front and enclose a transverse muscular area.
Beneath the beak are two crests supported by a short median septum ; posteriorly
these all unite to form a single apophysis grooved in
the middle and uniting with tlie inner surface of the
deltidium. The l)racliial valve has a prominent bifid
cardinal process, and a pair of small protuberances repre-
senting the crural plates ; from the base of the cardinal
process extends a median ridge which bifurcates ante-
riorly enclosing a cavity for the insertion of the ante- ';^;;7.,™'''uC'a^:;^'::"
rior adductors.

This division may liave some value in bringing into association species hav-
ing certain slight variations from the type of structure in Stropiieodonta demissa.

A few convex species in the later Devonian (<S. inequistriala, S. arcuata, S.
Cayuta, Hall, and S. variabilis, Calvin*), correspond witli the characters described
by Dr. Q5hlert, in having the muscular area of the pedicle-valve deepened and
its edges strongly elevated. In the brachial valve the anterior myophores
have the character of two diverging crests.

The genus Stropheouonta, though more prolific in species than Rafinesquina,
bears much the same relation to Devonian faunas as tlie latter does to the
Silurian. Its earliest members (Brachyprion) appeared while Rafinesquina still
existed, but the advent of the typical Stropheodontas was preceded by the
decline and extinction of the Rafinesquiiias. This fact is true not of the Amer-
ican Palasozoijc alone, thougli it is here best exemplified on account of the far
greater abundance of forms belonging to both groups.

species must belong to the same group of shells. Both species occur associated in the Devonian of the Bas-
Boulonnais, in France, and the environs of Voroneje, in Russia.

* This is a peculiarly v.iriable shell exteriorly, sometimes with the convexity normal, at otliei'S with the
convexity reversed nearly as in Strophonella, .and again the valves are at times nearly Hat, as in <S'. per-
plana.

290 PALEONTOLOGY OF NEW YORK.

Genus STROPHONELLA, Hall. 1879.

PLATE XU, FIGS. 1-21; AND PLATE XV B, FIG. 10.
1828. Leptwna, Dalman. KongL Veteiiskaps-Akadera. Handlingar. )). 108, pi. i, tif,'. 3.

1837. LepUsna, Hisinger. Lethipa Suecica, p. (59, pi. xx, fig. 4,

1838. Leptmna, Conrad. Second Ann. Rejit. Palseontological Dept. N. Y., pp. Hi, 117.

1839. LeptC^na, Sowerby. Murchison's Silurian System, p. 622, pi. xii, fig-. 1.

1840. Orthis, von Buck. Mem. Soo. Geol. de Fi-ance, vol. iv, p. 222, pi. xii, fiy. 20.

1842. StropliOjneiM, Vandxbm. Geology of N. Y. ; Rept, Third District, p. 122, fig. 5.

1843. Slrophmnena, Hall. Geology of N. Y. ; Rept. Fourth District, p. 101. fig. 3.

1846. OrlUs, McCoy. Synopsis Silurian Fossils Ireland, p. 30, pi. iii, fig. 11.

1847. Leptmna, Davidson. London Geological Journal, vol. i, pp. 56, 57, pi. xii, figs. 1-8.
1852. Leptmna, Hall. Paleontology of N. Y., vol. ii, p. 259, pi. liii, fig. 7.

1852. Leptmna (Strirplumieiia), McCoy. British Pa!a;ozoic Fossils, pp. 243, 244.

1857. Stnyi^lumenn (Stropkodonta), Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. 49-51, 53, 11 1,

figs. 1, 2.

1858. Stropkodonta, Hall. Geological Survey of Iowa, vol. i. pt. 2, p. 494, pi. iii, fig. 4.

1858. Strophmnena, Schmidt. Silur. Format. Estland, Nord-Livl. and Oesel, p. 215.

1859. Strophodonta, Hall. PaU-eontology of N.Y , vol. iii, p. 185-190, 193, 194?, 483, pis. xvi, figs. 13,

14 (?) ; xviii, fig. 3 ; xx, fig.?. 1-3 ; xxi. figs. 1-9 ; xxiii, figs. 1-7.

1860. Striiphmnena, F. Roembr. Sil. Fauna westl. Tennessee, p. 66, pi. v, fig. 3.

1861. StropJiomena, Billinos. Canadian Journal, vol. vi, p 345, figs. 119, 120.

1863. Sti-opkomena, Billings. Proceedings Poi-tUuid Soc. Nat. Hist., p. 108, pi. iii. fig. 2.

1863. Strophomena, Billings. Geology of Cana(l.i, p. 367, figs. 376. 378.

1865. Stropkodonta, Meek. American Journal of Science, vol. xl, p. 33.

1867 Stropkodonta, Hall. Pala;ontology of N. Y., vol. iv, pp. 93, 112, pi. xiv, figs, la-?,; pi. xix,

figs. 6, 7.
1868. Stvopkomena {Stropikodonta), Meek and Worthbn. Geol. Illinois, vol. iii, p. 374, pi. vii, fig. 10.
1871. Stro])homena, Kayser. Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, p 628, pi. xiv, fig. 3.
1871. .S7ro;j7«'?nt7(«, Davidson. British Silurian Br.acliiopoda, p. 288, pi. xl, figs. 1-5;)). 290, pi. xl,

figs. 9-13.
1874. Straphomt-na, Billings. Palieozoic Fosi?ils, vol. ii, p. 31, pi. iii, fig. 2.
1879. Strophondla, Strophodmda, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hist., p)i. 152,

154, pi. xxii, figs. 1-3 ; pi. xxiii, figs. 1-8.
1879. Strophomena, Barranue. Systeme Silurien <Ui Centre de la Boheme, vol. v, pi. xxxix, figs. 1-8.

1882. Slrophonella, Stroplwdonta, Hall. Eleventh Rept. State Geologist Indiana, i>p. '.290, 292, pi. xxii,

figs. 1-3 ; pi. xxiii, figs. 1-8.

1883. Stropkonella, Hall. Rept. N. Y. State Geologist for 1S82, pi. xii (43).

1884. Stropkodonta, Walcott. Palaeontology Eui-eka Dist., p. 121, )il. xiii, fig. 10.

1889. Stroplionella, Beecher and Clarke. Mem. N.Y. State Mus., vol. i. No. 1, p. -'5, pi. iii, figs. 1-S.
1889. Stropkodonta, Nettelroth. Kentucky Fossil Shells, p. 149.

Diagnosis. " Shells .semicircular or semielliptical, concavo-convex, resupi-
nate, the ventral valve concave and the dorsal valve convex. Ventral area
striated, solid, with or without a central deltidial scar, or rarely a partial
foramen, with similar features on the narrow area of the dorsal valve ; inner
margins of the cardinal areas of each valve crenulate, and from beneath the cen-
ter of the ventral area there is often a strong process (frequently bilobed) which
extends beyond the cardinal line. Muscular area of the ventral valve strongly

BRACHIOPODA. 291

marked, and limited by a prominent border. Dorsal valve with a narrow
hinge-area transversely or longitudinally striate or both, and marked in the
center by a deltidial scar. Cardinal process double, each division notched or
bidentate at the extremity ; muscular area quadrangular, occupying a more or
less elevated callosity, and a central carina rising from the lower part of this
area is sometimes produced into a spiniform pi'ocess in the center of the
cavity." — Hall, Twenty-eighth Rept. N. Y. State Mus. Nat. Hist, pp. 153, 154.
Type, Strophodonta semifasciaia, Hall.* Niagara group.

Observations. The shells included in this genus are essentially Stropheo-
dontas with the relative convexity of the valves reversed. It is evident from
a careful inspection of any well-preserved example of Strophonella, as already
shown from a study of very young individuals of S. striata, Hall, that in early
stages of growth the convexity of the valves is normal, reversion of convexity
obtaining with growth, f

* Since this is the fii-st-named species in the list it will probably be regarded by students as the " type "
of the genus, while in fact the generic description had reference to the better known Lower Helderberg
forms, and this name was written iii-st in a list of species given in their geological sequence, and including
in addition to S. semifasciata, S. Lmveivworthana, S. cavumbona and <S. punctulifem (the last two probalily
identical), of the Lower Helciei-berg group, aV. ampla, of the Uiiper Helderberg group, »S'. reversa, and
S. cwlata, of the Chemung group ; the interior characters of S. semifa-icUtta were less known than in any of
the others, and it was included in the group from its resupinate form and the character of the cardinal area,
deltidium, etc. In jS". semifasciaia, as in the eai-lier forms of other generic tyjies, the distinctive generic
features may not be, and usually ai-e not, as fully developed as they become in species of later geological
periods.

t Beecher and Clakke. Development of some .Silurian Brachiopoda, p. 25. Mr. Fobrste has shown
that the same conditions prevail in 8. patenta, as in 8. striata of the Clinton group of Ohio and other
localities, and writes as follows :

" This shell bejrins its existence with the ventral valve convex and the doi-sal concave. Later the ante-
rior and lateral margins of the ventral valve become concave or turned up, and that of the dorsal valve
convex or turned down. Since this is likewise true of Strophodimta striata, and only the exterior of these
specimens is found, as a rule, these species would be difficult to distinguish, were it not for the fact that
neither the convexity of the ventral valve, nor the point of strongest concavity of the dorsal valve, lies ever
so near to the cardinal line in S. pateiita as in S. striata. In other words, 8. pateiita remamed foi- a, longer
time a shell of simple curvatur-e."— Notes (m Clinton Group Fossils, with special reference to Collections
fi'om Indiana, Tennessee and Georgia, by Auu. F. Foerste. Pi-oceedings of the Boston Society of Natural
History, vol. xxiv, pp. 300, 301. 1889.

See, also, Strophomena pateiUa; Geological Survey of Ohio ; Palieontology, vol, ii, p. 115. 1875.

Whether this species is a Strophom ena or a Strophonella remains to be determined, as we do not yet know
the exact character of the hinge. The best specimens obtainable do not furnish conclusive evidence of
crenulations along this lin -, while they do show a broad open delthyrium, with evidence of a small apical
callosity, or dellidium. Should this species prove a Strophomena, it is the bust of its race, remarkable in
having reverted to a primitive or orthoid condition of deltidial structure. Nev(U-lheless the facts above given
are certainly of very great interest as showing the progressive generic development in certain forms of
Brachiopoda, and in this ca.se suggests the inquiry ;is to how far certain strophomenoid characters may
have been carried forwiird into Strophonella.

292 PALAEONTOLOGY OF NEW YaRK.

In Strophonella as in Stropheodonta, the earlier representatives possess
some of the generic characters in an incipient condition. Species are not
known to occur in faunas earlier than the Clinton, where this group is repre-
sented by (?) S. patenta and S. striata. The latter species is continued into the
Niagara group, where it is associated with i'. semifasciata, at Waldron, Indiana.
The genus is represented in Europe by S. euglt/pha and S. funiculata.

Strophonella striata, Hall, of the Niagara fauna, has a deltidiuni highly devel-
oped in the immature stages of the shell, a prominent deltidial callus, and a
short row of cardinal denticulations ; it is, in fact, in these respects a reversed
Brachyprion, bearing precisely the same relation to Strophonella in its fuller
development as that group does to Stropheodonta. The species also presents
some differences from the later Strophonellas in its internal characters. In
the pedicle-valve the muscular area is not enclosed, but its lateral margins are
bounded by two curved ridges continued from the dental plates. In the brach-
ial valve there is a similar arrangement produced by the continuation of the
crural plates, l)ut the muscular impressions are extremely faint, the radial
markings of the surf;ice extending quite to the base of the cardinal process.

Should it be considered useful to recognize the incipient and progressive
features of the species S. striata, and probably jS. patenta, towards a full manifesta-
tion of generic characters, and distinguish them from Strophonella in its more
mature condition of development, the term Amphistrophia may prove expressive
of their apparent double relation as shown in the young and mature shells.

In the other Silurian species of Strophonella the deltidiuni is more or less
prominently developed as a convex plate, but in the Devonian these parts assume
the character they possess in Stropheodonta demissa. In the species of the Lower
Helderberg and Devonian the muscular area of the pedicle-valve is deeply
impressed and strongly elevated at the margins, less like that of Stropheodonta
demissa than that of the later Stropheodontas. In the Lower Helderberg fauna
are the species S. Headleyana, Hall, S. cavumbona. Hall, iS. pundulifera, Conrad,
S. Leavenworthana, Hall, which possess all the typical features of the genus. It is
probable that Strophomena radiata and S. Conradi, Hall, belong to the same genus,
but their interior characters are not fully known. In the Upper Helderberg we

BRACHIOPODA. 203

have the single species S. ampla. Hall ; in the Hamilton group the genus is not
represented, but reappears in the eai-ly Chemung faunas in S. calata, S. reversa
and S. hybrida. Hall, the last two occurring both in New York and Iowa.

Genus LEPTELLA, gen. nov.

PLATE XVa, figs. 12-16.

1862. Leptwna, Billings. Pateozoic Fossils, vol. i, pp. 73, 74, tigs. Gtj, a. h, 67, a. h, c, p. 219.

1863. Leptmia, Billings. Geolog-y of Canada, p. 231, fig-s. 242, 243.

By the courtesy of Mr. J. F. Whiteaves, an opportunity has been afforded of
studying the original specimens of the species described by Mr. Billings as
Lept&na sordida, from Limestone No. 2, at Point Levis. These are in a silicified
condition and show very clearly all the essential features of their structure.
Though they are small, concavo-convex shells with an external aspect like that
of Lept.ena or Plectambonites, the character of the interior is such as to pre-
clude the admission of the species into any of the generic divisions now recog-
nized. A new name is therefore proposed for them.

Diagnosis. Shells small, normally concavo-conve.x. Outline semicircular or
semielliptical. Hinge-line straight, making the greatest diameter of the shell.
Pedicle-valve evenly convex, cardinal area moderately high, delthyrium for
most of its extent, covered by a convex plate ; teeth inconspicuous and un-
supported b}^ lamellae ; muscular impressions undetermined. Brachial valve
slightly concave ; cardinal area comparatively high ; the delthyrium filled by the
cardinal process, which, as viewed from behind, is divided by a median groove
for its entire height. On the cardinal margin this process is double but less
conspicuous than the crural plates, which are arched, and highly elevated above
the hinge-line. Tliey are short, terminate abruptly, and enclose deep sockets.
The visceral area is flattened or concave, its anterior margin forming a double
curve, from which line the surtace of the valve is abruptly deflected. This
visceral area is divided by a broad median ridge and its surface covered witli
fine, sharp radiating lines which end at the line of deflection.

Type, Lept(zna sordida, Billings. Quebec group.

294 PALEONTOLOGY OF NEW YORK.

The structure of the articulating apparatus is the essential basis of distinc-
tion between this fossil and Plectambonites, but there is also no trace of
the characteristic muscular scars of the latter genus. There can be little
doubt that tlie species Leptana decipiens, Billings, from the same formation and
locality, belongs to the genus Leptella. Without having had access to the
original specimens, the figure given by Mr. Billtngs of the interior of a brachial
valve,* showing the double, erect cardinal process, the strong crural plates and
the concave visceral area, seems sufficient to determine this point. Precisely
similar features are shown in Davidson's figures of his species Leptena Llandeilo-
ensis,\ from the Upper Llandeilo of Ayrshire, and it may also be included in
this genus.

The name Lept^enulopsis was proposed by Haupt, in 1878,J but as the work
in which it was described has not been accessible, no opinion can be expressed
in regard to its value. The term has been used by Jaekel,§ who refers to the
species Leptcznulopsis simplex, Haupt, certain small, smooth, semicircular, slightly
convex shells, of the age of tfie Wenlock shale. This author also observes
that Haupt included in this genus a few shells having the general aspect of
Chonefes minima, Sowerby ; but this, according to Dav[DSon, is a strongly plicated
shell, though without evidence of cardinal spines.

* Palsozoic Fossils, vol. i, p. 73, fig. 67 c.

t See Supiiloment to British Silui-iim Bi-achiopoila, p. 171, pi. xii, tigs. 26-29. 1883.

* Die Fauna dos Graptolithen-Gesteines; Ein Beitrag zni- Kenntniss der .silnrisi-hen Sediiuentar
GesdiiiOie der uoi-ddeutsc.hen El)eiie, vim Karl Haupt. Band liv des Neiien LausitziscOien Magazius,
Goi-litz, 1878, p. 31.

t Deber das Alter des sogen. Graptolithen-Gesteine.'? mit besonderer Bevlicksichtigung der in denselbeu
enthaltenen Graptolithen : Zeilschrift dry dcutsi-hen geolngisclien Gesellschaft, vol. xli, p. 69,'). 1890.

BRACHIOPODA. 295

Genus PLECTAMBONITES, Pander. 1830.

PLATE XV, FIGS. '26-29, 32-36; and PLATE XVa, FIGS. :«,:».

1828. LeptWiM, Dai.man. Kongl. Vetenskajis .\ca(l. Hamlliiii;-., p. lO'.l. pi. i. tig. 4 (not pp. 10(5-108).
1830. Plectamhonites. Pander. Beitr. zur Geognosie des russisoheii Reiches, p. 00. jil. iii, tig-.w. 8, 16;

pi. xxviii, tig. 19 (genei'ic tigmes) ; pi. xix, tig. I.
LeptcBna, of Davidson, 1853, 1871 ; Zittel, 1880; CEhi.ert, 1887, Jind authoi-s generally.
1840. Stnyphonuna, Conkad. Ann. Rept. Geological Survey of N. Y., p. 211.

1842. St rophoviena, Kmmons. Geology of N. Y. ; Rejit. Second Di.stric.t, p. 394, tig. 10.").

1843. Strophomena, Hall. Geology of N. Y. ; Rept. Fourth District, p. 104, tig. 4 ; p. 72, tig. 1.
1847. Leptcena, Hall. Palaeontology N. Y., vol. i, p. 110, pi. xxxi B, fig. 2; p 387, pi. Ixxix, tig. 3.

1852. Leptwna, Hall. Palaeontology of N. Y., vol. ii, p. 59, pi. xxi, fig. 1 ; p. 256, pi. liii, fig. 5.
1856. LepUena, Billings. Canadian Nat. and Geol., vol. i, p. 41, tig. 2; p. 138, pi. ii, tig.s. 14, 15.
1863. LepUHna, Billings. Geology of Canada, p. 163, fig. 139.

1865. Plectamhonites, Shaler. Bull. Mus. Comp. Zoology. No. 4. p. Ii4.

1873. LeptCBna, Meek. Geol. .Survey of Ohio, vol. i, p. 70, pi. v, fig. 3.

1874. Leptwna, Jame.";. Cincinnati Quarterly Journal of Science, vol. i, p. 151.

1875. LeptcBiia, Miller. Cincinnati Quarterly Journal of Science, vol. ii. p. 57.

1879. Leptwna, Ulrich. Journal Cincinnati Soc. Nat. Hist., vol. i, p. 15, pi. vii, fig. 12.

1853. Leptwna, Hall. Ann. Rept. N. Y. State Geologist for 1882, pi. xv (46), figs. 25-29, 34-36.
1885. Leptwna, Foerste. Bull. Denison University, vol. i, p. 79. pi. xiii. fig. 5.

1887. Plectamhonites, Shaler. Mem. Kentucky Geol. .Surv., V(}1. i, pt. 2.

Diagnosis. Shells usually small, normally concavo-convex. Surface cov-
ered with very fine striae, often alternating in size. Hinge-line making the
greatest width of the shell, the extremities often subauriculate. Cardinal area
narrow in both valves, sometimes obscurely crenulated on the margins. Pedicle-
valve with a moderately broad delthyrium which is partially closed by a convex
plate, but mostly occupied by the cardinal process of the opposite valve. Apical
foramen sometimes retained. Teeth prominent and supported by thickened
plates, which are continued in broad outward curves for more than half the
length of the valve, returning and uniting in the umbonal cavity, thus limiting
two linguiform muscular scars, enclosing a more or less clearly defined adductor
impression.

In the brachial valve, the dental sockets are deep, and often appear to tran-
sect the cardinal area. The cardinal process is simple and erect but by its
coalescence with the short prominent crural plates, the posterior face appears
trilobate. The crural plates end abruptly as in Orthothetes ; becoming thick-
ened at about the middle of their length, giving origin to two low ridges or
septa, which at first approach each other, and thence continue forward with a

296 PALEONTOLOGY OF NEW YORK.

slight divergence, thus forming the inner boundaries for two elongate muscular
scars, which are less sharply defined on their outer margins. The muscular
area is rendered quadripartite by two short transverse or oblique posterior fur-
rows. Vascular impressions radial, sometimes digitate. Shell-substance
fibrous, sparsely punctate.

Type, Pledambonites planissima, Pander. Lower Silurian of Russia.

Observations. In applying the term Plectambonites to the fossils usually refer-
red to the genus Lept.ena, as interpreted by Mr. Davidson in 1853, there is a
sufficient justification in the necessities of the case, and in the rights of pri-
ority. In this work the example of many of the earlier writers has been fol-
lowed, in applying the term Lept^na to the type of structure expressed in
Dalman's first and typical species, L. rhomboidalis.

If the progress of knowledge requires a stricter interpretation of generic values
than was prevalent a generation ago, at least no injustice has been done to the

Figs. 2;J, 2-1, •25. I'lirttnnlfonitfs pltniisamiii After PANDKl!.

founders of these groups. The first two of Dalman's four species of Leptjena
are synonymous with L. rhomboidalis ; the third, L. euglypha, Hisinger, belongs
to the genus Strophonella, Hall ; the fourth is L. transversalis, Wahlenberg, a
well known and widely distributed representative of the genus Plectambonites,
Pander, but which, under the conception of the genus, as rendered current by
Mr. Davidson, has served as the type of Lepttena.

The genus Plectambonites was thus defined by its author :
" Die Riickenfliiche ist wieder dreieckig, und wurde man nach ihrer Gestalt
allein sich richten, so miissten die hieher gehorigen Formen unmittelbar auf
die Orthamboniten folgen, allein wir miissen zu gleicher Zeit die ganze Gestalt
der Muscheln betrachten, und so sehen wir, dass diese, hauptsiichlich durch
die Starke Concavitiit der Unterschale, nJiher an Productus kommen. Die
Riickenfiache obgleich sie im Allgemeinen dreieckig, und anfangs ziemlich

BRACHIOPODA. 297

horizontal ist, niniiiit un Hohe allmiihlich ab uiid gelit iii eine Linie iiber, wie
bei Productus; 7A\ gleicher Zeit venimlert sie ihre Kichtung und indeiii sich der
anfaiigs iiach hinten hervorragende Hacken der Oberschale allmiihlich nach
unten umschlagt, endlich ganz uiiter die Unterschale zu liegen kommt, hat die
Riickeiilinie eiiie im VerhaUnisse zu den iibrigen Terebratulen verkehrte
Stellung angenonunen, so dass die Beri'dirung der beiden Schalen nacli oben,
der Hacken nach unten zu stehen kommt. Die Oberfiiiche der Plectamboniten
ist ghitt, mit tiachen, diinnen, durch breite ZwischenrJiume von einander ge-
trennte Langsstreifen versehen ; der Hacken ragt sehr wenig hervor. Obere
Schale mehr oder weniger, oft selir stark convex, die untere sehr concav, und
ahmt so sehr die Wolbung der oberen nach, dass zwischen beiden ein iiusserst
kleiner Zwischenraum iibrig bleibt, ja dass man selbst verleitet werden konnte
zu gdauben, man habe nur eine einzige Schale vor sich."*

In this diagnosis given by Pander the external characters of Lept^na,
Davidson (not Dalman), are very forcibly described, and although the internal
features are not detailed, the generic figure, given on plate iii, figure 8, of the
work cited, shows quite distinctly the peculiar cardinal process, crural plates
and conspicuous muscular scars characteristic of the brachial valve of this
group. Pander described twelve species of Plectambonites, the first of which,
P. planissima, must be taken as the type of the genus.

De Verneuil, in lS45,f recognized these specific terms, coml)ining many of
them, though retaining several of the original names. Under Leptena convexa,
Pander, he included P. planissima, P. crassa, and P. testudinata, and remarks that
he would have adopted the specific term planissima had it not been in use for a
species of Orthis.j

*" The cardinal area [posterior surface] is again triangular, and judging- from its outline alone, the
forms belonging to this gi'oup must follow directly upon Orthambonites, Init we must at the same time take
into consideration the entire form of the shell, ami thus we see that, mainly from the strong concavity of the
lower valve, they approach more closely to Pi-oductus. The cai'dinal area, though in general triangular and
at first nearly horizontal, gradually decreases in height and becomes linear, as in Productus; at the same
time it changes its direction and the projecting- beak of the upper valve, which at first is inclined backward,
becomes gradually incurved and finally comes to lie wholly beneath the lower valve, so that tlie cardinal line
has, in relation to the other Terehratuhus, a reversed position, and hence the surface of contact of the valves
is directed upwai-d an<l the beak downward [see figure 40, page 234]. The surface of the Plectambonites
is smooth with low, fine radiating lines separated by broad interspaces. The umbo is not very pi-ominent.
Upper valve more or less, often sti-ongly convex, the lower vei-y concave, and following so closely the cui-va-
ture of the upper that between them is a space so extremely narrow as to e:usily lead to the deception that
but a single valve is present."

t Gfeologie de la Russie et des Montagues de I'Oural, pp. :3'28-232.

X " Cette coquille, que M. Eichwald a cousideree comme nonvelle, nruis parait tellement identique avcc
le Plectainbonites planisaima de M. Pander, que nous n'aui-ious pas hesite a lui restituer ce nom, s'il n'avait

298 PAL/EONTOLOGY OF NEW YORK.

No author has been in a more favorable position for the study of Pander's spe-
cies than M. de Verneoil, and his testimony is of mucli accessory importance in de-
termining the real import of the genus Plectambonites. That he himself did not
adopt the generic term, is due to the fact that he followed the prevailing custom
of rendering to a genus the full breadth of meaning given to it by its author.

The elongate-lobate muscular scars, and the peculiar structure of the cardi-
nal process are features which at once distinguish Plectambonites from allied
genera. The former character is sometimes approached in certain species of
Rafinesquina. Species of this genus have probably not appeared earlier than
the faunas of the Trenton and Caradoc-Bala*

The genus disappears in the Niagara; P. transversaUs being the last survivor
represented. It has been quite generally believed that the genus reappeared
in the Trias and Jura, but many of these species have already proven to be of
a distinct type of structure, and all of them will unquestionably be found to
differ essentially from PLECTAMBONiXES.f

Genus C H Pv I S T I A N I A,^ gen. nov.

PLATE XV, FIGS. 32, Si; AND PLATE XVa, FIG. in.

1837. Plictnmbonitea, Pander. Beitr. ziir Geog'nosie d. russ. Reiche.s p. 92, pL xix, tiys. 9, 10.

1840. Orthis, von Eichwald. Ueber das Silur. Schicht. Syst. in Estlaiid, p. 148.

1845. LeptcBmi, db Verneuil. GeoL de la Russ. et des Mont, de rOural, p. 228, pi. xv, i\g. 2.

184(). PmdurtiL'), McCoy. Syniipsis Silurian Fossils of Ireland, p. 25, pi. iii, fig. 4.

ISii'i. Lept(Btta, Davidson. Introd. Biitish Fossil Brachiopoda, pi. viii, tigs. 184, 185.

1871. LeptcBna, Davidson. British Silurian Brachiopoda, p. 320, pi. xlvii, figs. 7-lS.

ISS3. Lepkena, Davidson. Bi-itish Silurian Brachiopoda, SuppL, p. 168, pi. xii, tigs. 17-21.

1S83. LepUeiM, Hall. Kept. N. Y. State Geologist for 1882. Expl. pi. xv (4G), tigs. 32. 33.

Diagnosis. Shells usually longitudinally elongated, sometimes semielliptical in
outline ; normally concavo-convex. Surface smooth or covered with fine radiat-

ete applique par M. Eichwald a une OrthU de I'Esthonie. Parmi les Plectambonites de M. Pander, il y en a
quati'e qui out une extreme ressemlileiice aux I'espece dont nous nous occupons Les Pleidambonltes planLt-
siiiM et wassa sont ceux que nous aurions voulu choisii- connne typos, mais ces deux noms ayant deja 6te
donnes a des Orthis on a des Atrypa, nous preferons adopter le nom de convexa qui n'a pas encore ete em-
ploye."

* The species Leptmn.a sardida and L. declpietut, described by Mr. Billings, from the Levis foi-matiou,
prove to be generically distinct, and are di.scusseil under the geiuis Leptblla.

t See the more recent detiu-miuations liy Mlniku de Chalmas, Bittnek, Zugmavku, and others. The
tir.st of tlii'se author.s lijis estalitished the genera Koninckklla (type, Li'.piOBMi llnnmit, Bou<-liard) and (^ad-
omklla (type, LeplcBna Monrei, Davidson), fm- some of the Liassic species.

% This name is proposed as an expression of regard for the memory <if Dr. Chkistian HKi.MiicH Pander.

BRACHIOPODA. 299

ing lines which are crossed by stronger, rather reguhir concentric plications.
In the pedicle-valve the cardinal area is moderately high and the delthyrium
in its normal condition probably closed by a convex plate. The teeth are very
divergent and from their bases extend the elevated margins of two linguiforrn
muscular scars, traversing the shell for almost its entire length. These scars,
which may be regarded as the diductors, enclose two, much shorter, but still
elongate adductors. In the br.achial valve the cardinal process is bipartite on
its anterior face, each of the lobes being grooved behind ; the crural plates are
very long and divergent, terminating in elevated extremities or crura. The
lower moiety of these plates is produced on each side of a strongly elevated
muscular ridge, curving slightly inward on the sides, then outward on approach-
ing the anterior margin of the valve, each branch recurving and passing back-
w^ard, parallel to the median axis, as far as the base of the cardinal process.
The symmetrical spaces thus limited are each divided transversely at about one-
third their length from the hinge-line, by a somewhat lower vertical ridge.
The four areas thus enclosed represent the posterior and anterior scars of the
adductor muscles. Between the inner muscular walls, in the median line, is a
low, rounded, longitudinal ridge.

Type, Leptana subquadrata. Hall. Lower Helderberg group.

Under the foregoing diagnosis it is proposed to include a few peculiar species
which have usually been referred to Lept^na, of the type of L. iransversalis
(= Plectambonites). While they resemble in many features the structure of
this group, there are important differences; in the composition of the cardi-
nal process ; in the arrangement of the muscular scars, and in the surface
ornamentation. The most striking of these peculiarities are the great muscular
scars bounded by high walls. In the pedicle-valve the outer diductor scars
are much more elongated than ever in Plectambonites, and in the brachial
valve the adductors have the quadruplicate ai'rangement usually seen to the
best advantage in species of Ortiiis. In Plectambonites Iransversalis, however,
these adductor impressions, though greatly elongated, are iK^arly parallel to each
other, all converging toward, or meeting in the umbonal region.

300 PALMONTOLOGY OF NEW YORK.

There arc; at least three well known species which are clearly referable to
this proposed genus : Leptana subquadraia, Hall,* from Perry county, Tennessee,
referred to the age of the Lower Helderberg group ; Leptmna tenuicincla, McCoy,
elaborately described by Mr. Davidson,! from the Upper Llandeilo and the
Caradoc series ; Pledamhonites ovata and P. oblonga, Pander, which are united
by UE VerneuilI under the term Leptana oblonga, from the Lower Silurian
Ijeds in the vicinity of St. Petersburg. Davidson includes in L. tenuicinda the
Lepfana ccnigma of ue Verneuil,§ from the Lower Silurian Ijeds of the Lsland of
Gotland, a shell mucli less elongated than the typical L. tenuidnda, and whose
interior has not been described.

Genus LEPTiENISCA, Beeciier. 1890.

PLATE XV, FIGS. 30, 31; AND PLATE XVA, FIGS, in-30.

18.59. LepkeiM. Hall. Paleontology of N. Y., vol. iii, p. 197, pi. xviii, iig. 2,

1S83. Leptwna? (sub-genus?), Hall. Kept. N.Y. StateGeologist for 1882 ; Expl. pi. xv (46), tigs. 30. 31.

1890. Lf'ptmnisca, Beecher. American Journal of Science, vol. xl, p. 238, pi. ix, tigs. 1-9.

Diagnosis. " Shell concavo-convex, attached to foreign objects by calcareous
cementation of the ventral beak. Valves articulated by the teeth and sockets.
Dorsal or socket valve concave ; interior with a broad, more or less defined,
spiral impression on each side of the median line, making a single volution.
Adductor impressions small. Cardinal line [area] narrow, bearing in the center
two prominent, bilobed, cardinal processes, separated to admit the vertical
septum in the opposite beak. Ventral valve convex, area elongate-triangular,
fissure covered with a pedicle-sheath. Cardinal muscular scar supported on, or
limited by a vertical septum, on each side of which, in the anterior half, is a
small adductor scar. Shell-structure punctate.

" Type, Leptana concava, Hall."* Lower Helderberg group.

This interesting genus includes a few species of attached shells having the
general form and contour of Plectambonites, but with a peculiar combination

*This species is tirst mentioned and illustrated in the Report of the N. Y. State Geologist for 1882,
explanation of plate xv (46), tigs. 32, 33. 1883.

t British Silurian Brachiopoda, pp. 326-328, pi. xlvii, figs. 7-1 S.

X Geologie de !a Russie, etc., p. 228, pi. xv, fig. 2.

§ Bulletin de la Soci6t6 Geologique de Fi-ancc, 2e Ser., vol. v, p. 340, pi. iv. fig. 6. 1S48,

II Bkkcmkh. "On LuiT.'Ti.NLSf'A, a newjgeniis of Bi-.-u-hiiipod from (lie Lower Helderberg group" (op. cit.)

BRACHIOPODA. 301

of internal characters, the most striking of which are, the strong dental lamellae,
prolonged into the interior of the valve as vertical walls, forming the lateral
boundary of the muscular impression; the cardinal process, quadrifid on its
posterior and bifid on its anterior face ; the very large, broad, much elongated
spiral brachial ridges, which make something more than a single convolution.

It is observed by Mr. Beecher that these spiral ridges are better comparable
to the so-called reniform impressions of the productids than to the brachial
supports and ridges in Koninckixa and Davidsonia. Elsewhere will be found
quoted the opinion of the late Professor Neumayr, that the reniform impres-
sions in Chonetes, Productus, etc., were produced by the coiled arms of the
animal. The presence of a cardinal process like that in Choxetes and Pro-
DUCTELLA seems to sustain the view of the closer relations of Lept^nisca to
this rather than any other group of the articulate brachiopoda. In regard to
the degree of attachment of the pedicle- valve, two additional species, from the
same formation, afford some interesting facts. Leptanisca concava has the cica-
trix restricted to a very narrow area about the umbo ; L. tangens, a smaller
species, is usually found adhering to branches and fronds of bryozoa, and the
scar is often deep and may cover the umbonal area ; while L. adnascens is
attached by the entire external surface of the pedicle-valve, generally to shells
of other brachiopods, preferably to Orthis. A young individual of the last
species retains the brachial valve, and shows a well defined cardinal area and a
prominent arched deltidium.

Genus DAVIDSONIA, Bouchard 1849.

PLATE XVa, figs. 31-33.

1845. LepUBnaf, db Vbesboil. Geol. Rusaie et des Mont, de rOural, p. 227, pi. xv, fig. 9.

1849. Davidsonia, Boochabd. Annals des Sciences Naturelles. 3d Ser., vol. xii, p. 92, pi. i, fig. 2.

1852. Davidsonia, de KosiiXK. Mem. de la Societe Royale de Liege, vol. viii, p. 149, pi. i, figs. 1-4 ;

pi. ii, fig. 1.

1853. Davidsonia, Datid.so.v. Introd. British Fossil Brachiopoda, p. 110, \<\. \\\\, figs. 186-193.
1853. Davidsimia, Schxdr. Palseontographica, vol. iii, p. 219. pi. xxxix, fig. 4.

1855. Davidsonia, de Koxi.vck. Mem. de la Societe Royale de Liege, vol. x, p. 281.

1858. Davidsonia, Davidsos. The Geologist, No. xi, pi. xii, tigs. 33, 34.

1865. Davidsonia, David.so>-. Bi-itish Devonian Bi-achiopoda, p. 74, pi. xi, tigs. 13-16 ; pi. xv, fig. 18.

1871. Davidsonia, Qcesstedt. Peti-efactenk. Deutschl.-inds, Brachiopoden, p. 6S9, pi. Ixi. figs. 103-109.

1S71. Davidsonia, Kayskr. Zeitschr. iler deulsch. geolog. Ge.selLsch., vol. xxiii, p. 632, pi. xii, fig. 9.

302 PALAEONTOLOGY OF NEW YORK.

Diagnosis. Shell thick, plano-convex, transversely oval. Surface smooth
or with concentric growth-lines, fixed to foreign bodies by the umbonal portion
and the greater part of the surface of the pedicle-valve. Hinge-line straight
and quite narrow. On the pedicle-valve the delthyriuni is covered by a con-
vex imperforate plate ; the teeth are large, the dental lamellae obscure. The
muscular area is comparatively small, lying in the umbonal region, and is sub-
divided into two cardinal scars enclosing an elongate adductor. In the pallial
region there is a low median septum which separates two conical callosities of
the shell, having their apices directed toward the opposite valve. These pro-
tuberances are grooved by a spiral furrow which makes five or six volutions,
and are frequently crossed by vascular sinuses.

In the brachial valve the deltidial covering is convex, embracing the base of
the posterior tace of the cardinal apophysis. The cardinal process has very
mucli the same structure as in Plectambonites, consisting ol a central, short,
erect process, to which the crural plates are attached, giving it a trilobate
appearance. These plates terminate abruptly at their distal extremities. The
muscular area is quadruplicate and of about the same size as in the opposite
valve. Two conical depressions in the pallial region correspond to the protuber-
ances of the opposite valve. Shell-substance punctate (?).

Type, Davidsonia Verneuili, Bouchard. Middle Devonian.

Observations In 1859, de Koninok detected the existence of calcified spiral
brachial supports in this genus, which would give it somewhat the character of
Atrvi'A. Dr. (Ehlert has placed the genus with some doubt in the family
KoifiNCKJifiij^, with Koninckina, Anoplotheca, Koninckella, Amphiclina, The-
cospira; the last of these genera being similarly attached by the surface of tlie
pedicle-valve, and all of them being spirigerous.

Davidsonia occurs in the middle Devonian (Crinoiden-schichten) of the Eifel,
and at an essentially equivalent horizon in England, Belgium and Russia. But
two species have been described, D. Verneuili, Bouchard, and D. Bouchardiana, de
Koninck, the latter being regarded by P. Roemer and Kayser as identical with
the former. The genus is not represented in American faunas, so far as known.

BRACHIOPODA. 303

Genus CHONETES, Fischer de Waluheim. 1837.

PLATE XVa, figs. 11-lS; and PLATE XVI, FIGS, l-ll, U, 15, lS-2:, 32-:iB, 39, 41, 13, 44.

1793. Peeten. Ure. History of Rutherg'len iind East Killn-ide, p. 317, pi. xvi, ti^-s. 10, ]].

1820. HysteroUtheStTerebratiditex, Schlothei.m. Die Petrefacktonkimde auf ihi-. Jetz. Staiiilimnkt.

1828. Leptwiia, ton Bcch Abhaiidl. Akad. WisseiiscVi. zu Bi'i-lin, pp. 53, 70, pi. iii.

1828. Orlhis, Dalman. Kong-1. Vetenskaps Akad. Handliiifjai', p. Ill, pi. i, tig' ").

1834. Orth'w!, Leptcena, KloDBN. Verstein. Mark Brandenburg, pp. 179. 181.

1836. Orthis, Leptmna, Goldfuss, von Bdch. Abhandl. d. KiJnigl. Akad. d. ^Yis.*e^s(■h. zii Berlin.

1836. Spin/era, Phillips. Geology of Yorkshire, vol. ii, pi. ii, tig. G.

1837. Chonetes, Fischer de Waldheim. Oryctographie du Gouv. de Moscou, pt. ii. j). 131, pi. xxvi,

figs. 8, 9.
1837. Orthis, Hisinger. Lethaea Suecica, p. 70, pi. xx, Rg. 7.
1839. Stroplioviena, Conrad. Second Ann. Rept. Paleont. Dept. N. Y., p. 64.
1841. Orthis, Leptce/ia, Phillips. Paleozoic Fossils Cornwall. Devon and West Somerset, \t. 138, pi. Ix,

fig. 104.
1841. Orthis, D'Archiac and db Vernedil. Descr. Foss. Rhenish Provinces, p. 397.

1841. Productiis, vox Buck. Abhandl. d. Konigl. Akad. d. Wissensch. zu Berlin, p. 25.

1842. iStrophonwna, Conrad. Journ. Acad. Nat. Sci. Phila., vol. viii, pp. 253, 257, pi. xiv, figs. 1, 13.
1842. Stropho}iiena, VAiinxBM. Geology of N. Y. ; Rept. Third District, p. 149.

1842. LeptwiM, Producing, d'Orbigny. Voyage dans I'Amerique Miiridionale, Paleontologie. p. 49,

pi. iv, figs. 10, 11.

1843. LeptcBim, de Castelnau. Essai sur le Systeme Silurien de TAmdrique septentrionide, p. 39.

pi. xiv, fig. 9.

1843. Strophomena, Hall. Geology of N. Y. ; Rept. Fourth District, pp. 73, 171, 175, 180, 222.

1844. Leptcena, McCoy. Synopsis Cai-b. Fossils Ireland, p. 27.

1S44. Delthyrls, Fahkenkohl. Bemerk. iiber einige Foss. d. Moskow und Kaluga Gouv.

1845. Chonetes, de Vernedil. Geologic de ia Russie et des Mont, de I'Oural, p. 242.

1846. ChoTietes, Morris and Shakpe. Quarterly Journal Geological Society London, vol. ii. ]>. 274.

pi. X, fig. 14.

1847. ChoTietes, db Konisck. Recherches sur les Animaux Fossiles, pp. 192, 200, 204, 206, 215.
1852. Chonetes, Hall. Stansbury's Expl. Great Salt Lake, p. 410, pi. iii, fig. 1.

1852. Chonetes, Hall. Paleontology of N. Y., vol. ii, p. 64, ])l.'xxi, fig. 10.

1852. Chonetes, Owen. Rej^t. Geol. Survey Iowa, Wisconsin and Minnesota, p. 583, tab. v, fig. 12.

1854. Chonetes, Davidson. Introd. British Fossil Brachiopoda. p. 113.

1854. C?t07ietes, Norwood and Pratten. Joui'n. Acad. Nat. Sci., Philadelphia, vol. iii, pji. 24-30,

pi. ii, figs. 2, 4-12.

1855. Chonetes, Shdmard. Geology of Missouri, pp. 201, 202, 216, pi. c, fig. 1.
1855. Leptcena, McCoy. British Palaeozoic Fossils, p. 454.

1857. Chonetes, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., pp. lit:. 119, 145-150

1857. Chonetes, Shdmard. Engehuann's Rept. Bryan's Expl. from Ft. Leavenworth to Bryan's Pass.

1858. Chonetes, Stevens. American Journal of Science, vol. xxv, p. 263.

1858. ChoTietes, Meek and Hatden. Proc. Academy of Natural Sciences, Phila., vol. x, p. 262.

1858. Chonetes, Hall. Rept. Geol. Survey of Iowa, vol. i, pt. ii, p. 598, pi. xii, figs. 1, 2.

1859. Clionetes, Shimard. Trans. St. Louis Acad. Science, vol. i, p. 390.

1860. Chonetes, Wokthen. Trans. St. Louis Acad. Science, vol. i, p. 571.
1860. Chonetes, Hall. Canadian Natui-alist and Geologist, vol. v, pp. 144, 145.

1860. Chonetes, Meek and Worthen. Proc. Academy of Nat. Sciences, Phila., )). 450.

1861. Chonetes, Newberry. Ives' Rept. Colorado River of the West, p. 128.
1861. Cftt»jejes, Billings. Canadian Journal Science and Arts, vol. vi. p. 349.

304 PALAEONTOLOGY OF NEW YORK.

1861. Clmutes, Davidson. Bi-itish Cai-bonifei-ous Bracliiopoda, pp. 1S2-191. pi. xlvi, fiifs. 3-7 ; pi. xlvii,

lig-s. 1-7, 12-18, 25, 28.

1862. Chonetes, A. Winchell. Pioc. Acad. Nat. Sci. Phila., vol. xiv, pp. 410, 411.

1862. Clumetes, VfaiTE. Proc. Boston Society Natural History, vol. ix, p. 29.

1863. Choiietes, A. Winchbll. Pi'oc. Acad. Nat. Sci., Phila., vol. xv, p. 5.

1863. Chonetes, Billi.ngs. Geology of Canada, p. 368.

1864. Clwnetes, -Mkkk and Hayden. Palffiontol?)g-y of Upper Missouri, p. 22, pi. i, fig. 5.

1865. Chonetes, Davidson. Britisli Devonian Bracliiopoda, pp. 94-96, pi. xix, figs. 4-12.

1865. Chonetes, A. Winchell. Proc. Academy of Natural Sciences Phila., p. 116.

1866. Chonetes, A. Winchell. Geological Rept. Lower Peninsula Miciiigan, p. 92.
1866. Chonetes, Geinitz. Carbon und Dyas, pp. 58, 60, pi. iv, tigs. 12-18.

1866. Chonetes, Meek and Wokthen. Geological Survey of Illinois, vol. ii, i>. 253, pi. xviii. tig. S.

1867. Chonetes. Hall. Palaeontology of N. Y., vol. iv, pp. 115-145, pi. xx, figs. 1-7; pi. xxi, figs. 1-13;

pi. xxii, figs. 1-28, 44.

1867. Chmetes, Ha-li.. Twentieth Rept. N. Y. State Cab. Nat. Hist., p 242.

1868. CJiimetes, Meek and Worthen. Geological Survey of Illinois, vol. iii, p. 505. pi. xv, fig. 8.
1868. Cho7utes, Meek. Trans. Chicago Acad. Sciences, vol. i, p. 93, pi. xiii, fig. 2.

1870. Chimetes, A. Wi.ncheli. Proc. Amer. Philosophical Society, vol. xii, p. 250.

1870. Chonetes, Meek and Wobthen. Proc. Acad. Nat Sci. Phila., p. 35.

1871. Chonetes, Davidson. Bi'itish Silurian Brachiopoda, pp. 331-335, pi. xhx, figs. 13-26.

1872. Chonetes, Meek. Final Rept. Paleeont. Eastern Nebra-ska, pp. 170, 171, pi. i, fig. 10 ; pi. iv,

figs. 9, 10 ; pi. vi, fig. 10 ; pi. viii, figs. 7, 8.

1873. Chonetes, Meek and Worthen. Geol. Survey of Illinois, vol. v, p. 570, pi. xxv, fig. 11.

1873. Chonetes, Nicholson. Palaeontology Pi-ovince of Ontario, pp. 74, 75.

1874. Chonetes, Ratubun. Bull. Buffalo Soc. Nat. Hist., vol. i, pp. 250-253.

1874. Chonetes, Derby. Bulletin Cornell University, vol. i, pp. 41. 43, ])1. vi, figs. 3, 12, 19 ; pi. viii,

figs. 11, 14, 15, 19; pi. ix, figs. 8, 9.

1874. Chiiveies, BiLi.iNfiS. Palaeozoic Fossils, vol. ii, pp. 15-29.

1874. Chonetes, White. Prelim. Rept. Wheeler's Surv. we.st 100th Mcrid., i>. 19.

1875. Chonetes, White. Geogr. and Geol. Surv. west 100th Merid., pp. 121-123.pl. ix, figs 6-8.

1876. Chonetes, Meek. Stimpson's Survey Great Basin of Utah, p. 348.

1876. Chonetes, Hall. Document Ed. Twenty-eighth Rept. N. Y. State Mns. Nat. Hist., pi. xxii, fig. 15.

1877. Chonetes, Hall and Whitfield. U. S. Geological Expl. Fortieth Par.'illel, p. 253, pi. iv, tig. 9.

1878. Chonetes, Dawson. Acadian Geology, Third Edition, pp. 595, 596.

1879. Chonetes, Hall. Twenty-eighth Rept. N. Y. State Mus. Nat. Hi.st., p. 1.55, pi. xxii. figs. 11- 15.
1879. Chonetes, Emerson. Geology of Frobisher Bay ; Nourse's Narr. Hall's Arctic Expedition.
1879. Chonetes, Ratiibdn. Proc. Boston Society Natural History, vol. xx, jip. 18-21.

1882. Chonetes. Hall. Eleventh Ann. Rept. State Geologist Indiana, p. 293, pi. xxii, figs. 11-15.

1882. Chonetes, Whitfield. Geology of Wisconsin, vol. iv, p. 327, pi. xxv, fig. 10.

1882. Chonetes, Davidson. British Devonian Bracliiopoda, Supplement, pp. 54, 55, ])1. iii, figs. 23, 24.

1883. Chonetes, Hall. Rept. N. Y. State Geologist for 1882, plate xvi (47).

1884. Chonetes, Hall. Thii-ty-fifth Rept. N. Y. State Mus. Nat. Hist., pi. xxii, fig. S.
1884. Chonetes, Waawen. Salt-Range Fossils ; Brachiopoda, [ip. 614-640, pis. Iviii-lxi.

1884. Chonetes, Walcott. Paleontology Eureka Dist., pp. 123-127, pi. ii, figs. 8, 13 ; pi. xiii, tigs. 14, 15.

1884. Cho7ietes, White. Thirteenth Ann. Rept. State Geologist Indi.-ina, p. 128, pi. xxv, figs. 7, 8.

1885. Chonetes, Clarke. Bull. No. 16, U. S. Geological Survey, p. 24.

1888. Chonetes, Keyes. Proc. Academy of Natural Sciences Phila. (Extract), pp. 7, 8, pi. xii, fig. 3.

1888. Clumetes, Merrick. Bull. Deni.son University, vol. iii, pp. 35-37, pi. i, fig. 4 ; pi. ii, fig. 21 ; pi. iii,

figs. 12, 14, 21 ; pi. vii, fig. 22 ; pi, xii, fig. 3.

1889. Clionetes, Nkttelrotu. Kentucky Fossil Shells, pp. 60-68, pi. xvii, figs. 16-19; pi. xviii, figs.18-20;

pi. xxxi, figs. 20, 30.

1889. Chonetes, Semp.son. Trans. American Philosophical Society, p. 438.

BRACHIOPODA. 305

Diagnosis. Shc41s semicircular or transverse, usually norinally concavo-
convex, sometimes plano-convex. Hinge-line straight, making the greatest
diameter of the shell. Pedicle-valve with a narrow concave or flat cardinal
area; the delthyrium more or less completely covered by a convex imperforate
deltidium. The upper margin of the area bears a single row of hollow vertical
or divergent spines, which increase in length toward the cardinal angles ; these
spines are the prolongations of tubes which penetrate obliquely the substance
of the shell in the cardinal region, converging toward the apex of the valve
till they reach the surface, where they turn at an abrupt angle upward and out-
ward and are thence continued as hollow spines. Cardinal teeth strong. A
low median ridge, slightly thickened at its posterior extremity, where it is
sometimes coalesced with the deltidium, extends forward, dividing the mus-
cular region. The muscular scars are usually faint, and consist of tlabelliforra
diductors which partially enclose elongate median adductors.

In the brachial valve the cardinal area is very narrow, and without spines.
The deltidium is partially developed, resting against the cardinal apophysis
This process is very similar in character to that in Plectambonites, consisting
of a median portion, coalescing at its base with the elongate crural plates. On
its posterior face it is divided by a narrow median furrow and two broader
lateral grooves, giving it a quadrilobate appearance. The crural plates are
slightly divei-gent from the hinge-line, bounding narrow, elongate sockets. A
median ridge separates the quadruplicate muscular impression, and from between
the anterior and posterior members of this impression originate two linear
brachial ridges, which extend outward, recurving toward the median line at
about the middle of the valve, making a reniform curve. Interior surfixce of
both valves strongly papillose in the pallial region.

External surface usually covered with radiating striae, rarely smooth or con-
centrically rugose. Shell-substance fibrous-punctate.

Type, Orthis striaiella, Dalman. Upper Silurian.

Observations. Chonetes is remarkable for the persistence of its characters.
From its appearance in the middle Silurian to its disappearance in the Permian,
this type of structure has been maintained with few essential modifications. On

306 PALMONTOLOGY OF NEW YORK.

account of this stability in its features it is difficult to establish any satisfactory
subdivision of its members, especially since the genus has been left more com-
pact by the recent elimination of some of its aberrant forms De Koninck
proposed* a classification of the species into five sections, based upon the
nature of the external ornamentation, as follows:

I. Concmtrica, those with concentric folds or undulations, like C. concentrica.
II. Comata,, those with more than one hundred smooth radiating striae.

III. Striata, those in which the striae are less than one hundred and more

than thirty.

IV. PlicosdR, those with less than thirty striae.

V. Rugosa, those with rugose radiating plications.
An additional group was proposed by Mr. Davidson, viz., Laves, to include
smooth shells, like C. polita, McCoy, C. glabra, Geinitz, etc. ; and Waagen has
more recently added another, Grandicostate, for species with very strong and
high radiating ribs. Such an arrangement as this is of course quite conven-
tional, and can not meet the requirements of an exact classification, though it
may still serve a useful purpose in the absence of a better one. Of the first of
DE Koninck' s sections, Concentrica, we have no representation in American faunas.
The second and third were properly united by Waagen, and will include the
great majority of all known species ; the Plicosa may embrace such forms as
C. mucronata and C. lepida. Hall ; of the Rugosce. and Grandicostata, we have no
representatives. The Laves are a group characterizing the Carboniferous and
Permian, 'of which we have the species C. glabra, Geinitz,! while C. polita,
McCoy, occurs in the Carboniferous throughout Great Britain, and Waagen
has described^ five additional species of this type from the Productus-liraestone
of India.

The genus Chonetes presents many points of structure in common with
Plectambonites. This fact is best .seen in the usual size and general contour

* Monog-i-aphie ties genres Productus et Ohonttes. 1847.

t The species C <//oi^m, Geinitz, aiul C. IcEvis, Keyes, are .synnnymcms ; the former having- precedence
in time must stand, since the C glabra. Hall, has been shown to lie identical with C liiieata, Vanuxeni ; Pal.
N. Y., vol. iv, p. 121.

J Salt-R.anjje Fossils, vol. i, pi. iv, pp. 61G, et seq. 1884.

BRACHIOPODA. 307

of the shell, and in the cardinal area and articulating apophyses, and may
be regarded as of some significance in determining the source and point of
departure of the productoid stock. CEhlert has demonstrated the existence
of reniform or hook-shaped brachial ridges in the genus Stropheodonta {S. Le-
blanci) ;* and although a feature of extremely rare occurrence in that group,
it should be given full value in its bearing upon the same question. It has
been remarked by many observers that in the earlier forms of Chonetes the
reniform ridges are but faintly, if at all, manifest; the more distinctly pro-
ductoid characters of the genus becoming pronounced only with the advent
of Productus. f The peculiar cardinal tubes, which are continued into
spines, sometimes of a length equal to that of the valves, constitute a featui'e
found only in this group of shells, including Chonostrophia and Chonopectus,
here described for the first time, Chonetina, Krotow, and Chonetella,
Waagen. The existence of these passages across the ventral area, opening
into the interior of the shell, was first observed by Keyserling,J and was dis-
cussed at length in Volume IV of the Palaeontology of New York,§ and more
recently by Mr. John Yoonq, in Davidson's Appendix to his Supplement on
the Brachiopoda.il Fine hair-like spines are sparingly scattered over the striae
in C. papilionacea, Phillips, of the Carboniferous limestone, and traces of similar
processes have been mentioned by various writers for other .species.TI

It is probably true in many cases that the supposed bases of ttie spines are
but the coarse punctations of the inner laminse of the shell-substance, exposed
by the abrasion of the impunctate outer or epidermal layer. Furthermore, the
Chonetes papilionacea is a species whose generic affinities are still debatable.
The shell is of immense size, far exceeding that of any other form referred

* Annales des Sciences Geologiques, vol. xix, p. 6'i.

t CEhlekt observes "cjue les modifications du g-enre Chonetes ont lieu tout imrticnli^rement a I'epoque
carbonifti-e, et que leur tendance dans certaines especes, a <le rapprocher <le la i'oi-ine productoide seinble
co'incidei- avec I'apparition et la cleveloppeinent maximum du geni-e Productus. Les Chonetes d6voniens, et
surtout ceux qui appartiennent a I'epoque silunenne, pi-esentent des (taracteres plus nettement dfeflnis etplus
facilement reconnaissables."

I Geogn. Beob-ichtuug-en auf einer Reise in das Petschoi-a-land, p. 213. 1846.

§ " " •• •■ p. 117.

l «' " " " p, 281.

If See Davidson, Carboniferous Brachiopoda, p. 188, pi. viii, fig. 8 b. 1872 ; Waagen, Salt-Range Fos-
sils, genus Chonetes.

308 PALMONTOLOGY OF NEW YORK.

to the group, and this fact, taken in connection with its spinous striae, leads to
the presumption that the interior, when known, will show some generic varia-
tions of more or less importance.

The earliest appearance of Chonetes in American Palaeozoic faunas, is in the
Clinton group (C cornuta, Hall) ; Chonetes undulata, C. tenuistriata, C. Novascotica,
Hall, are known in the Niagara fauna. There is an undescribed species in the
Lower Helderberg, and at least one other in the Oriskany sandstone of New
York, but these are of rare occurrence. Billings has described from the Lower
Devonian (Oriskany horizon) of Gaspe and the Bay of Chaleurs, C. Canadensis
and C. Antiopia. In the Devonian the species multiplied rapidly, and then
attained their maximum development, both in number and size ; becoming less
conspicuous in the following faunas, as the productoids increased in develop-
ment and importance.*

Whether the cardinal spines are ever absent in true Chonetes is not yet posi-
tively determined; they are often obscure, and as often lost from accidental causes,
but no satisfactory evidence of their non-existence has been shown in any species
that can be strictly referred to Chonetes; although Waagen believes that
they were probably never developed in one of his species from the Salt-Range.
An analogous structure is exhibited by the species Leptmna ? nudeata, Hall,f
a small, obscure shell, occurring in great abundance in certain outcrops of the
Oriskany sandstone in New York and Illinois, and in the Upper Helderberg
chert of Cayuga, Province of Ontario. In contour the shell is concavo-convex,
and externally is unlike Chonetes in having a smooth surface with concentric
squamose lines or lamellag of growth, but no radiating striae, and no spines,
either on the cardinal margin or over the surface. The delthyrium appears to
have been uncovered. On the interior the pedicle-valve has a broad, thick and
considerably elevated median septum, which takes its origin at, or just in front
of the apex and is continued over about one-third the length of the shell, end-
ing quite abruptly. In well preserved internal casts the impressions of the

* Waage.v observed (1884), when adding to the genus fourteen new species from the Produotus lime-
.stone, that only about sixty species had been previously known, according to Zittel. This estimate is fai-
too low, since just al)OMt sixty well defined species have been described from American faunas alone.

t Paleontology of New York, vol. iii, p. 419, pi. xdv, figs. 1 a-d.

BRACHIOPODA. 309

teeth are moderately developed, and indicate considerable divergence in the
dental ridges. A most remarkable feature on these casts, is the presence, on
each side of the umbo, of a minute, greatly elongate and gently tapering cone,
the base of which is joined to the cast at about two-thirds the distance from
the apex to the cardinal angle; and from this point each one is inclined toward
the apex of the shell, and terminates in a free extremity. These delicate
cones which are so fragile that they are easily lost and rarely preserved,
penetrate, but do not transect the cavity originally filled by tlie substance of
the cardinal portion of the valves ; they are evidently the casts of a single pair
of large and very oblique spine-tubes, which were not continued into spines as
in Chonetes, and evidently did not penetrate to the outer surface of the cardi-
nal margin. The inner opening of these blind tubes is situated below and in front
of the cardinal area, and their obliquity greatly exceeds that observed in the cardi-
nal tubes of Chonetes. The muscular impressions consist of two tlabellate diduc-
tors, between which lie two elongate, narrow adductors. Over the pallial region
the surface is pustulose. In the brachial valve the cardinal process appears to
be simply bilobate, the crural plates narrow and obscure. From the base of the
cardinal process extend two slightly divergent median ridges which are con-
siderably elevated at the center of the shell and terminate abruptly. These
enclose an elongate muscular scar. There are also two lateral ridges curving
outward and then inward, enclosing small thickened areas which appear to be
of muscular origin, while the ridges themselves have the curvature of, and
suggest the " reniform impressions." Nearly the entire inner surface of this
valve is covered with radiating rows of strong pustules. This curious shell
represents a phase of development in the chonetid type not hitherto described
and it may be convenient to separate it under the sub-generic name Anoplia.*
Illustrations of the only species known to possess these features, Leptczna ?
nucleata, will be found on Plate XV a, figures 17 and 18, and Plate XX, figures
14-17.

*Mebk and Worthen, in describing' this species under the niinie Leptmna'^ midiata (Palaeontology of
Illinois, vol. iii, p. 394 ; 1868), observed that '• this curious little shell does not pi-esent the form or internal
cliai-acters of Lbpt^na, and will i)robably be; (bund to be a new genei'ic type."

310 PALEONTOLOGY OF NEW YORK.

Genus CHONETINA, Krotow. 1888.

18S4. Clionetella, Krotow (not Waagen). Artinskische Etage, p. 274.
1888. ChonetiiM, Krotow. M6m. du Comite G6ologique, vol. vi, p. 500.

A brief description of the characters of this genus* has l)een given by
CEHLERT,f from which it appears that " Chonetina differs from Chonetes by its
very convex ventral valve, having a profound sinus ; the small valve, very
concave, follows the curvature of the larger ; in the interior of the dorsal valve
are tubercles arranged in radiating series which unite to form high, compact
lamellsB, extending from tlie beak to the anterior margin ; two of these, more
prominent than the rest, limit the surface occupied by the sinus of the larger
valve. The type, C. artiensis, Krotow, belongs to the horizon of the Artinskian
grit (Permian)."

Without actual knowledge of the specimens upon which this separation from
Chonetes has been based, it may be imprudent to express an opinion as to the
value of the proposed genus. The American species which are deeply sinused
on the pedicle-valve, e.g., Chonetes Verneuiliana and Ch. mesoloha, Norwood and
Pratten, show no valid grounds for separation from Chonetes.

Genus CHONOSTROPHIA, gen. nov.

PLATE XV u, FIGS. U-19 ; AND PLATE XVI, FIGS. 13, '.».

18.57. Chonetes, Hall. Tenth Kept. N. Y. State Cab. Nat. Hist., p. 56

18.59. Cho7iete.i, Hall. Palaeontology of N. Y., vol. iii, p. 4^, pi. xciii, figs, la-d, 2c.

1882. Chonetes, Whitfield. Annals N. Y. Academy of Science, vol. ii, p. 213.

188S. ChimetiK, Hall Rept. N. Y. State Geologist for 1S82, pi. xvi, fifjs. 13, 29.

Diagnosis. Shell reversed, concavo-convex, the pedicle-valve being slightly
convex about the umbo, but becoming broadly concave over the pallial region.
Outline and contour strophomenoid ; valves extremely tenuous and compressed ;
surface covered with fine, .alternating or fasciculate strise. In the pedicle-valve
the upper margin of the cardinal area bears a row of hollow spines of the same
structure and arrangement as in Chonetes. The delthyrium is narrow and
appears to be more or less completely closed. The teeth are quite strong and

*The original descriptions of both genus and species are in the Russian language.
t L'Ainuiaii-e g^ologiipic nniversel, vol. v, p. 1152. 1889.

BRACHIOPODA. 311

rest upon the bottom of the valve ; between them arises a low median septum
which may be traced from one-third to one-half the length of the valve, divid-
ing a subcordate muscular area, the outer margins of which are distinctly
elevated.

In the brachial valve the crural plates are united to form a bilobed cardinal
process. The outer face of this process has not been observed ; on the
inner surface it is not continued into a median septum but ends abruptly.
Muscular area very faintly defined in the type-species. Internal surface over
the pallial region finely papillose. Shell-substance fibrous, punctate.

Type, Chonetes reversa, Whitfield. Corniferous limestone.*

Observations. The peculiar species which is taken as the type of this new
division occurs in the fauna of the Corniferous limestone, at Delaware, Ohio,
and Cayuga, Province of Ontario. Certain of its peculiarities indicated will
not permit its strict generic association with Chonetes, e.g., the reversed con-
vexity and surface ornamentation of the valves, and the apparent structure of
the cardinal process. In a general sense the relation between Chonostrophia
and Chonetes is the same as that between Strophonella and Stropheodonta,
Strophomena and Rafinesqoina ; but, as in these cases, the reversal of the rel-
ative convexity of the valves is not the only difference of importance. Chonetes
complanata, Hall, of the Oriskany sandstone, a much larger, more transverse
form, also with reversed convexity and with more strongly developed flabelli-
form muscular areas, may be placed in the same division until its characters
shall be more fully determined. In a different facies of the same fauna is an-
other, as yet undescribed congeneric species ; and Mr. Billings has described* a
form from an equivalent horizon at Gaspe, Chonetes Dawsoni. In the shaly
limestone of the Lower Helderberg series, there occurs a species described in
this volume as Chonostrophia Helderbergia, sp. nov.

* The honzon of this species in Ohio is considered by Mr. Whitfield (Annals of the New York Academy
of Sciences, vol. ii, p. 212 ; 1882), the equivalent of the Marcellus shales of New York, on account of its
association with a few species of the New York fauna. The character of the sediments is, however, alto-
gether dift'erent, the i-ocks at Delaware, Ohio, being lai-gely calcareous. They lie at the top of the Cornifer-
ous .series in that State and are included in this series by Profes.sor Orton, in his First Report of the Thii'd
Geological Survey of Ohio, 1890. The association of the species in the Province of Ontario is invariably with
characteristic forms of the Corniferous fauna.

* Palaeozoic Fossils, vol. ii, p. 18. 1874.

312 PALEONTOLOGY OF NEW YORK.

Genus CHONOPECTUS, gen. nov.

I'LATE XVB, FIGS. '20-23; and PLATE XVI, FIGS. 17, 31.

1854. Chonetes, Norwood and Prattbn. Journal Acad. Nat. Sci. Phila., vol. ii, p. 2ii.
XS5S. Chonetes, Hall. Geological Survey of Iowa, vol. i, pt. ii, p. 517, pi. vii, fig. 1.
1883. Clioncffs, Hall. Second Ann. Rept. N. Y. State Geolog-ist, pi. xvii, fig. 17.

This niime is proposed for the species, Chonetes Fischeri, Norwood and
Pratten, a hirge, normally concavo-convex shell, witli a sub-semicircular
outline ; occurring in the oolitic limestone and yellow sandstone of the Burling-
ton beds of Iowa. In this species the cardinal margin oi^ the pedicle-valve
bears a row of erect spines, as in Chonetes. The beak is often compressed
or distorted in such a manner as to leave a flattened area, which resembles,
and probably is a cicatrix from attachment in early growth. This charac-
ter is more prominent in some individuals than in others, and appears to have
become consideraby obscured by the later growth of the shell. The surface
ornamentation is also peculiar ; the shell bearing a double oblique series of
concentric lines, which give to the surface the appearance of the engraving on
a machine-turned watch case. These lines are wrinkles rather than striae, and
are strongest over the umbonal and central region, where traces of them may
.sometimes be observed on internal casts of the valves. The wrinkles are
crossed by a normal series of very fine concentric growth-lines, and beneath
these, but not always exposed, are exceedingly fine, crowded, radiating striae,
usually very much interrupted in their course from beak to margin, and often
tlexuous and irregular. Sometimes the surface is entirely free from the double
series of concentric wrinkles, and marked only by the fine radiating and con-
centric striae.

The internal muscular impressions of the species have not been fully deter-
mined. Casts of the pedicle-valve show the impression of a short median
septum dividing two broad obcordate flabelliform muscular .scars, from the outer
margin of which sometimes originates a series of irregularly radiating furrows
or ridges, which were probably of vascular origin. Impressions of a very nar-
row cardinal area and exceedingly small hinge-teeth are also seen on internal
casts of this valve.

BRACHIOPODA. 313

Genus CHONETELLA, Waagen. 1884.

1884. Chondella, Waage.v. Mem. (ieol. Survey of India ; Palaioiitolojfia Imiica, yurie.s xiii, vol. i,

No. 4, J). 0,57, jil. Ixxxi, tigs. 3-8.

Diagnosis. Shell small, normally concavo-convex. Surface rounded, witli
radial striiE ; cardinal area narrow ; deltidiura, cardinal .spines and teetli as in
Chonetes. In the pedicle-valve the adductor impressions are elongate, and are
partially enclosed by the larger cardinals. The brachial valve has a small
trilobed cardinal process, which is continued into a low median septum. The
muscular area is quadrijjartite and very distinct. The
brachial ridges are sharply defined and appear to origi-
nate near the outer extremities of the posterior adduc- \1
tors, making a broad outward, and a more abrupt inward
curve completing one volution. Surface in the pallial
region strongly papillose. ,, „^ ,., , „

Type,ChoneteUa reaiwto, Waagen. Upper Carboniferous. xncvwwr.Eti.

Observations. Dr. Waagen has proposed this division for a single species
from the Productus limestone of India. Aside from the broadly curved brachial
ridges, its characters are so strongly chonetoid as to render its separation from
Chonetes exceedingly difficult.* The author surmises that some small shells
figured by Davidsonj and regarded by liim as varieties of Productus longispinus,
from the Carboniferous shales of Lanarkshire, Scotland, belong to the same
group.

*The trilohed cardinal process is de.serilied in its anterior aspect onlj', and it is quite pi'obable that upon
Us posterior face it would be found more similar to that of Chonetes. The ci-ural plates are very obscure,
making the process appear free and erect ; but this is also true of some species of Chonetes, e.g., Chcmetes
coronata, Conrad.

t Carboniferous Brachiopoda, pi. xxxv, figs. 18. 19.

314 PALjEONTOLOGY OF NEW YORK.

Genus STROPHALOSIA, Kino. 1844.

rL.VTK XVli, FIGS. -H-.H; plate XVI, FIGS, li, 1(5. 30, 38, i-2; FLATE XVII, FIGS. 10-I.->, ."in, .il; AND PLATE XVllA,

FIGS. 1-9.

18H9. Spmidylii.''. Mun.ster. Beitr. zui- Petrefaotenkuiule, Heft i, p. 43, jil. iv, fig-. 3.

1842. Orth'is, Gkinitz. Neues Jahi-lmch fiir Min.. etc., p. 578, pi x, tig-s. 12, 13.

1843. Strophomf-na, Hall. Geology of N. Y. ; Rept. Fourth District, p. 189, fig. 4.
1S44. Stroplialosia, King. Annals and Magazine of Natural History, vol. xiv, p. 313.
184.'). Leptmnaloiiia, King (MS.). In de Vei'neuil's Geol. de la Rii.«s , etc., vol. ii, p. 281.

1846. StniphaUma, King. Annals and Magazine of Natural Hi.story, vol. xvii, p. 92.
1S47. Orthothrix, Geinitz. Bull. Imp. Soc. des Nat. de Moscou, vol. xx, p. 84.

1847. Productus, de Koninck. Monographie de.s genres Productus et Chonetes, pp. 14S, 150, pi. xi,

fig. 4 ; pi. XV, tigs. 4, 5.

1848. Orthofhiix, Geinitz. Verstein. der deutsch. Zechst.-gebirg., p. 14, pi. v, figs. 27-37; \>l. vi, fig. 20.
1850. Stroplialosia, King. Monogr. Permian Fossils of England, p. 93, pi. xii, figs. 1-33.

1853. Strophalosia, Davidson. Introd. British Fossil Brachiopoda, p. 115.

1855. Leptaena, McCoy. British PaUeozoic Fossils, p. 457.

1857. Strophahisia, Davidson. British Permian Fo.ssils, p. 38, \A. iii, figs. 1-10, 19-4J.

1857. Produrtella, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 171.

1861. Strophalosia, Geinitz. Dyas, p. 93, pis. xvii, figs. 1-19, 21-39 ; xviii, figs. 1-20 ; xix, figs. 2-6, 26.

1863. Strophalosia, A. Winchell. Pi-oc. Acad. Nat. Sci., Phila., vol. 15, p. 4.

1866. Vraiiia, A. Winchell. Rept. Lower Peninsula of Michigan, p. 92.

1867. Chonetts. Hall. Paleontology of N. Y., vol. iv, p. 143, pi. xxii, figs. 29-43.
1S67. Produclella, Hall. Paheontology of N. Y., vol. iv, p. 160, pi. xxiii, figs. 12-24.

1868. Aulostige.s, White and St. John. Ti-ans. Chicago Acad. Sci., vol. i, p. 118, fig. 2.
1874. Strophalosia, Dekby. Bull. Coi'nell University, vol. i, No. 2, p. 45, pis. iii, iv, viii, ix.

1883. Chonetes (Productella, Slrophalusia), Hall. Ann Rept. N. Y. State Geologist for 1882, pi. xvi

(47), figs. 12, 16, pi. xvii (48), figs. 10-15, 50, 51.

1884. Productus (Prodiictdla), Walcott. Palseontology Eureka District, p. 131, pi. xiv, fig. 2.

1884. Striiphnlosia, Waagen. Salt-Range Fossils ; Brachiopoda. pji. 640-657, pi. ixiii, figs. 2-8 ; pi. Ixiv,

figs. 1-9 ; pi. Ixv, figs. 1-9.
1889. ProduvliUa {Stnijihahisia), Whiteaves. Contributions Can. Geol., vol. i, ji. 112, pi. xvi, figs. 1, 2.

Diagnosis. Shell.'* prod uctoid in general form; a cicatrix, u.sually apparent
on the umbo of the pedicle-valve, indicates that they were attached to foreign
bodies by the sul)stance of the shell. Both valves have a well defined area
and covered delthyrium, these features being much the more conspicuous in
the pedicle-valve. In this valve the teeth are prominent, but not supported by
lamellae ; the muscular arrangement is the same as in Productus, though the
cardinal impressions are relatively larger and more elongate, extending beyond
the iiinit.s of the central adductors.

In the brachial valve the cardinal jirocess is erect, bifid on its anterior, and
quadrilid in its posterior face. It is supported on each side by short, arched
crural plates, and is continued into a median .septum which extends for half

BRACmOPODA. 315

the length of the valve. Muscular impressions small, quadruple, not dendritic,
the interior pair being sharply raised. The brachial ridges originate from
between the adductor scars, curving gently outward, recurving, at first grad-
ually and then abruptly to their anterior limit ; then turning suddenly back-
ward, and again inward horizontally, meeting the median septum near its
anterior extremity.

Surface of the pedicle-valve covered with spines, which near the beak are
often curved backward, embracing some external object. In some species all
the spines of the valve have evidently been at least of accessory importance in
eftecting its attachment. The surface of the brachial valve may be either
spinous, lamellose or smooth.

Type, Orthis excavata, Geinitz, = S. Goldfussi, (Miinster) Davidson. Permian
of Europe.

Observations. The existence of cardinal areas, delthyria, and articulation,
the form of the brachial ridges, and the substantial attachment of the shell
either in youth or throughout its existence, make an association of characters
which serve to readily distinguish this genus from its allies. The genus
Strophalosia is not very abundant!}' represented in species ; all the generic
characters described are typically developed only in the Permian mem-
bers of the group.* In the earlier forms of the Devonian and Lower Car-
boniferous, the expression of the shells is often quite distinct from the later
species, though not affording any satisfactory basis for separation. The
existence of an articular system and of cardinal areas is not sufficient of itseli'
to distinguish Strophalosia from Productella; and it will therefore be neces-
sary to base distinctive generic value upon the umbonal attachment of the
former.

In the mature condition of the Permian species the umbonal cicatrix of the
pedicle-valve is often obscure, having become somewhat obliterated, during
their probably free condition near, and at maturity. As observed in the
diagnosis, the spines in such species are frequently turned backward in such a
manner as to leave the impression that they were certainly flexible, and prob-

* See Waaobn, Salt-Range Fossils ; Brachiopoda, p. 640.

316 PALEONTOLOGY OF NEW YORK.

ably attached to some extraneous body, a phenomenon which has been noticed
in Prodoctus (P. complectens and other species). In some of the earlier species
of this genus, e.g., S. radicans, Winchell, of the Hamilton group, S. scintilla,
Beecher, of the Choteau limestone, and S. Keokuk, Beecher, of the Keokuk
group, the entire shell is small, and the pedicle-valve attached by almost its
entire surface ; the spines on these valves are all attached, creeping like root--
lets in irregular, tlexuose lines over the surface of the host. A Permian form
similar to these was described by Professor King,* under the name S. parva,
which may be the young of some of the larger associated species; but the
Hamilton and Lower Carboniferous forms can not, with our present knowledge,
be regarded as undeveloped shells. The affinities of Strophalosia with both
Chonetes and Aulosteges, serve to make the transition from the chonetoid
shells to Productus a complete and very easy one.

No satisfactory subdivision of the species of Strophalosia has been" made.
Dr. Waagen described a number of new species from the Productus limestone
of India, and proposed a grouping therefor upon the basis of the general form
of the shell. It may l)e suggested that a good basis for a provisional subdivi-
sion of the genus can be found in the character of the external surface of the
brachial valve. This valve is spiniferous, as in S. excavata, Geinitz, and the
majority of the species ; lamellose, or covered with concentric lamelloe or
varices of growth, as in S. lamellosa, Geinitz; or smooth, as in S. Leplayi, Geinitz,
jS. plicosa, Waagen, iS'. radicans, Winchell, etc.

In American faunas Strophalosia is of rare occurrence. The following
species only may be safely referred to the genus : Producta truncata. Hall, of the
Marcellus and Hamilton faunas ; Chonetes muricatus, and Productella hystricula,
Hall, of the Chemung group ; Crania radicans, Winchell, from the Hamilton
group ; S. numularis, Winchell, of the Marshall group ; S. scintilla, Beecher, of the
Choteau limestone; S. Keokuk, Beecher, from the Keokuk group, and probably
Aulosteges spondyliformis, White and St. John, from the Coal Measures. To
these may be added S. Rockfordensis, sp. nov., from the Upper Devonian of
Iowa. None of these species, however, show tlie typical development of the
interior found in the Permian forms.

♦ Monograph of the Pei-inian Fossils of England, p. 102, pi. xii, fig. 33.

BRACHIOPODA.

317

Mr. Davidson, in his Devonian Brachiopoda,* has referred the Devonian
species, Orthis produdoides, Min'chison, to Strophalosia, but it shows no evidence
of attachment, and more properly belongs to Productklla. Professor King
had previously made a similar reference of this species,f and included in the
same genus Produdus subaculeatus, Murchij^on, an unattached species, subse-
quently taken as the type of Productella.

Genus DAVIESIELLA, Waagen. 1884.

1823. Pi-odacttis, Sowerry, Mineral Conchology, vol. iv, pi'- fil. •'-i'-

1837. LepUeiia, Fischer. Oryctogr. du Goiivern. de Moseoii, p. 143, jil. xxii, %. 1.

1842. Produeta, d'Archiac and de Vehneuil. Trans. Geol. Soc. London, 2nd Ser., vol. vi. jif. ii, ji. :i97.

1846. Chonetes, de KEYSBRLiNr;. Beol). Reise in das Petschora-land, p. 214, pi. vi, fig-. 1.

1847. Chonetes, de Koninck. Monogr. dn Geni-e Chonetes, p. 189, pi. xix, fig-. 1.

1861. Chonetes, Davidson. British Carboniferous Brachiopoda, p. ISO, pi. xlv, figs. 1-7.

1862. Productus, Uavid.son. Brit. Carli. Brachiopoda, pp. 275, 277, pi. xlvi, fig. 1 ; pi. Iv, fig-s. 6-10.
1884. Daviesiella, Waagen. Mem. Geol. Siirv. India ; Palseontologia Indica, Sei-. xiii, vol.i, No.4,p. 618.

Dr. Waagen writes :

"I create this genus for the reception of such forms as Produdus Llangollensis,
Dav., and Prod, comoides, Sow., which are characterized by cardinal teeth and a
second pair of adductor impressions in the ventral valve. The other characters
are like those of Productds. Mountain limestone." — op. at.

'27. Pfoiluctus {Daviesiella) Llavr/oUc.nsis, Davidson.
Alter Davidson.

* Page 97.

t Periiiiau Fossils, p. 95.

318 PALAEONTOLOGY OF NEW YORK.

The two species named are large, ponderous shells, having the cardinal area and
teeth conspicuously developed, the external surface covered with fine radiating
striai, and devoid of spines The existence of the secondary muscular scar in
the pedicle-valve can hardly be regarded as a distinctive feature, since it is also
well defined in some other species of Productus. The form and size of the
shells, the arrangement of the muscular scars, and their dendritic markings,
and the structure of the cardinal process, all show the very close relationship
of these species to the typical forms of Proddctus. It will be difficult to find
features of intrinsic importance upon which to justify the separation of these
fossils from Productella, unless it be in the spineless surface ; and yet the
general form and expression of the shells is so different from what we are
accustomed to meet with in that distinctively Devonian genus, that for the sake
of homogeneity in the grouping, it may be well to retain for them this desig-
nation.

Both P. Llangollensis and P. comoides are from the Welsh Coal Measures, and
may be regarded as the final expression of that combination of characters con-
stituting Productella in earlier faunas.

BRACHIOPODA. 319

Genos AULOSTEGES, von Helmersen. 1847.

PLATE XVU, FIGS. 47-49.

1845. Orthis, de Vbrnedii,. GM. Russ. (i'Europe et ties Mont. I'Oiiral, vol. ii, p. 198, pi. xi, fig-. 5.

1847. Aulosteges, von Helmeksbn. Neues Jahrb. fiir Mineral., p. SSO.

1847. Aulosteges, von Helmersen. Bull. Acad. Imp. Sci. St. Petersboui-^, vol. vi, ]>. 18."), pi. vi, fig. 12.
1850. (i) Strophalosia, King. Monogr. Pei'iiiian Fossils England, p. 93.

1853. Aulosteges, Davidson. Introd. British Fossil Brat-hiopoda, p. 116, jil. ix, tigs. 212-216.

1848. Aulosteges. Shumard. Trans. St. Louis Acad. Science, vol. i, p. 292, pi. xi, fig. 5.

1861. Strophalosia, Geinitz. Dyas, Heft i, p. 93.

1862. Aulosteges, Davidson. Quarterly Journal Geological Society, vol. xviii, p. 3'A, pL ii, fig. 7.

1863. Aulosteges, de Koninck. Fossiles psilfeozoiques de I'lnde, p. 41, pi. xii, fig. 7.

1883. Aulosteges, Hai.l. Ann. Rept. N. Y. State Geologist for 1882, pi. (xvii) 48, figs. 47-49.

1884. Aulosteges, Waaubn. PaUeontologia Indica ; Salt-Range Fossils, vol. i, pt. iv, p. 661, pi. Ixii,

figs. 1-4 ; pi. Ixiii. fig. 1.

Diagnosis. Shell productiform in general a.spect, somewhat depressed, not
attached. On the pedicle-valve the cardinal area is prominently developed,
frequently somewhat distorted ; the delthyrium is closed by a convex deltidium
which is covered with little tubercles or spinules. Cardinal teeth rudimentary
or absent. In the brachial valve the cardinal area is linear, the cardinal process
large, quadrifid; its base being surrounded by a strong deltidial callosity. Bra-
chial ridges extending nearly to the anterior margin and abruptly incurving.
Otherwise the interior impressions are as in Produotds. Surface of both valves
thickly set with spines.

Type, Aulosteges variabilis, von Helmersen,^ Orthis Wangenheimi, de Verneuil,
Permian of Russia.

Observations. It was early observed by King that Aulosteges formed a
connecting link between Strophalosia and Productus. The constant presence
of the cardinal area and the usual absence of the hinge-teeth, show the correct-
ness of this observation as far as it bears upon the structure of these genera.
Aulosteges is chiefly if not wholly of Permian age, and it may perhaps be better
to regard it as a descendant or offshoot from Strophalosia ; showing the obso-
lescence of teeth, which is the tendency toward the prevailing brachiopod type
of that and the preceding fauna. The specific representation of Aulosteges
is quite meager. The original species, A. Wangenheimi, de Verneuil (which,
according to King, Davidson and others, is identical with, and therefore has

320 PALEONTOLOGY OF NEW YORK.

priority over von Helmersen's A. variabilis), is from the Permian of northern
Russia. Davidson recognized no species in the British formations, though King,
in 1856,* considered his Produdus umboniUatus {=P. laiirostratus, Howse) an
AuLOSTEGES. Davidson described A. Dalhousii, and Waagen A. Medlicottianua,
from the Permian of the Salt-Range of India. In America but two species
have been referred to this genus, namely, A. Guadalupensis, G. C. Shumard, from
the Guadalupe Mountains of Texas, a very imperfect shell, insufficiently illus-
trated, but showing a high cardinal area; and A. spondyliformis. White and St.
John, from the Upper Carboniferous beds of Iowa ; a form which it would be
difficult to separate from Strophalosia on the basis of the features given in
the original description and figures.

Mr. R. Etheridge, Jr., in discussing "Adherent Carboniferous Productid£e,"f
has figured (figs. 2-4) and described a shell which he regards as Chonetes,
adherent by its spines (figs. 2, 3) and the outer surface of the pedicle-valve to
foreign objects. This discussion is one of great interest and will be referred to
at greater length in regard to some important points established in this and a
previous paper on the same subject, by Mr. Etheridge. There is some room for
doubt, however, whether these shells should be regarded as belonging to the
genus Chonetes. The individual represented in figure 4 of his work, a pedicle-
valve with area and delthyrium, attached by its outer face, and covered with
spines creeping over the surface of the host, can hardly be anything but a
Strophalosia of the type of S. radicans, S. Keokuk and S. scintilla. The subject
of the other figures, a shell in which one of the cardinal spines encircles a
spine of Productus, is quite imperfect but has a more decided chonetiform ex-
pression. It will be interesting to learn more of this peculiar form.

* A'lnala and Mag'azine of Natural History.

t Qiiiirtcrly .louriial Geological Society, vol. xxxiv, p. 498. 1S7.S.

BRACHIOPODA. 321

Genus PRODUCTUS, Sowerby. 1812.

PLATE XVIIA, FIGS. lS-24; PLATE XVUI. FIGS. 6-19; AND PLATK XIX, FIGS. 1-23.

1778. Anomia, Da Costa. British Concholog^y.

1780. QryjyJiites, Walcu. Beitr. zur Geschiclite der Gi-yjihiten.

17S5. Ano)iua, Pyxis, Chemnitz. Neues Systemat. Konchylien-Kabinet, vols, vii, viii.

1789-92. .^rca, Bbugdiebb. Hist. Naturelle iles Vers testaces.

1793. Anomia, Ure. History Rutherglen and East Kilbride, p. 314.

1801. Tridaciia, Lamakck. Aniinaux sans Vertebres.

, 1809. Anomites, Martin. Petref'acta Derbiensia, pis. xv, xvi, xxii, xxxii, xxxiii, xxxvi, xxxvii.

1811. Trigimia, Pakkinson. Organic Remains, vol. iii, ]il. xii, fig. 11.

1812-14. Productus, Sowbrby. Mineral Conchology.

1826. Protania, Linck. Haiulb. d. jiliysikal. Erdbeschreib.

1 826-33. LeptCBna, Goldfuss. Petrefacta Germanife.

1828. Lc'ptwna, Dalman. Uppstalln. och Beskrifn. Sver. funne Terebrat.

1829. Terehratida, Rang. Manuel de I'hist. natiir. des Mollusques, etc.

183'. Mytilus, Fischer. Oryctogr. du Gouv. de Moscou, p. 181, pl. xix, fig. 4,

1831. Arbtt-ii-uUtes, Murray. Acc't of A. argentea fi-om Garb, limest.

1835. Pruductiis, Conrad. Trans. Geol. Soc. Penna., vol. i, p. 268, pl. xii, fig. 5.

1836. Productus, Morton. American Journ. Sci. and Arts, p. 153, pl. ii, tig. 2; pl. xxxix, figs. 38, 39.

1836. Pi-oducta, Pinna, Phillips. Geology of Yorkshii-e, vol. ii.

1837. LeptCBua, Fischer. Oryctogr. du Gouv. de Moscou, p. 144, pl. xxi.

1838. Productus, Shepard. Am. Journ. Sci. and Arts, vol. xxxiv, p. 153.
1840. Lima, Von Buch. Karsten's Arcliiv. fiir Mineral. Geogn. etc., p. 60.

1840. Pecten, Eicuwald. Bull, scientif. de I'Acad. de St. Petersboui-g, vol. vii, p. 86.

1841. Clavagella, Goldfu.ss. Petrefacta Germanis, vol. ii, p. 283, pl. clx, fig. 17.

1841. Ltptwna, J. db C. Sowerby. Mineral Conchology, vol. vii, pl. 615.

1842. Productus, D'Orbigny. Voyage dans I'Amerique Meridionale PaliEontology, pp. 51-55, pl. iii,

figs. 24-26. i>l. iv, figs. 1-9, 12, 13, pl. v, tigs. 4-10.
1844. Leptama, McCoy. Synopsis Charact. Carbon. Limest. Ireland, pl. xix, fig. 12.

1844. Stropliomtna, Potiez .and Michaud. Galerie des Mollusques de Douai, vol. ii, pl. xlii, fig. 5.

1845. Productus, de Verneoil. Geol. de la Russie et des Mont, de I'Oural, p. 246.
1845. Productus, db Verneuil. Travels in North America, vol. ii, p. 221.

1847. Productus, DK KomxcK. Recherches sur les Animaux fossiles ; Monogr. du genre Productus.

1851. Leptwna (partim), de Koninok. Descr. des Animaux. Foss. du Terrain Carl), de Belgique.

1852. Productus, Owen. Geol. Surv. Wisconsin, Iowa and Minn., pp. 103, 136, 584, pl. v, figs. 1, 3.

1852. Productus, Hall. Stansbury's Expl. Great Salt Lake Region, p. 412, pl. iii, figs. 3, 5, 6.

1853. Productus, Shumard. Marcy and McClellan's Expl. Red River of Louisiana, p. 201, pl. i, fig. 5 ;

pl. ii, fig. 1.

1854. Productus, Norwood & Pratten. Journ. Acad. Nat. Sci. Phila., vol. iii, pp. 6-20, pl. i, figs.

1-3, 5, 6, 8-11 ; pl. ii, fig. 1.

1855. Producta, McCoy. British Palseozoic Fossils, p. 473.
Productus of authoi-s generally.

1855. Productus, Schiel. Rept. Expls. and Sui-vs. from the Mississippi River to (he Pacific Ocean,

pl. i, fig. 3 ; pl. ii, figs. 4, 5.

1855. Productus, Shomard. Geol. Rept. Missouri, pp. 201, 216, pl. c, fig. 10.

1856. Productus, Hall. Rept. Expls. and Survs. from Miss. River to Pacific Ocean, vol. iii, p. 1(13.

pl. ii, figs. 16, 17.

1857. Productus, Prout. Trans. St. Louis Acad Science, vol. i, p. 43, pl. ii, figs. 1-16.
1857. Productus, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 180.

322 PALEONTOLOGY OF NEW YORK.

185S. Froductus, Hall. Geol. Survey Iowa, vol. i. part 2. pp. 635-639. 674, 675, 712, pi. xii, fig-. 3;

pi. xix, figs. 1-4 ; pi. xxiv, tigs. 1-3 ; pi. xxviii, tigs. 3^.

185S. Productm, Hall. Trans. Albany Inst., vol. iv, pp. 12, 13.

1S58. Productiis, Swallow. Trans. St. Louis Acad. Sci., vol i, pp. 181, 1S2, 215-217.

1858. Productm, Suumard. Trans. St. Louis Acad. Sci., vol. i, pp. 290-292, pi. xi, fig. 8.

1858. Prodnctiix, Rogers. Geol. Penna , vol. ii, part 2, \>. 833.

1858. Productm. Marcou. Geology North America, pp. 45-48, pi. v, figs. 3-6 ; pi. vi, figs. 1, 3-7, 12.

1859. Produclns, Meek and Havden. Proc. Acad. Nat. Sci. Philii., pp. 25, 26.

1860. Productm, Meek. Proc. Acad. Nat. Sci. Phila., vol. xii, p. 309.
1860. Productus, Meek and Worthen. Ibidem, pp. 450, 451.

1860. Productm, Worthek. Ti-ans. St. Louis Acad. Sci., vol. i, \\ 570.

1860. Producttis. White. Jouni. Boston Soc. Nat. Hist., p. 230.

1860. Productm, Swallow. Trans. St. Louis Acad. Sci., vol. i, pp. 640, 641.

1860. Productm, McChbsnet. Descrip. New Species Paljeoz. Foss., pp. 34-40.

1861. Productus, Salter. Quart. Jour. Geol. Soc. Lond., vol. xvii, p. 64.

1861. Productm, Newberry. Ives' Rept. Expl. Colorailo River of the West, pi). 121-125, pi. i, tig. 7 ;

pi. ii, tigs. 1-10.

1861. Productus, Meek & Worthen. Proc. Acad. Nat. Sci. Phila., p. 142.

1862. Productus, White. Proc. Best. Soc. Nat. Hist., vol. ix, p. 29.

1863. Productm, Swallow. Ti'ans. St. Louis Acad. Sci., vol. ii, pp. 91-94.

1863. Producta, A. Winchbll. Proc. Acad. Nat. Sci. Phila., vol. xv, p. 4.

1864. Productm, Mbbk. Palaeontology of California, vol. i, p. 11, pi. ii, fig. 4.

1865. Productm, A. Winchell. Proc. Acad. Nat. Sci. Phila., jip. 112-115.

1866. Productus, Geinitz. Carbon .and Dyas in Nebraska, pp. 52, 54, 81, pi. iv. figs. 1-11.

1866. Productm, Meek & Worthen. Geol. Surv. Illinois, vol. iii, pp. 280, 297, 320, pi. xx, fig. 5; pi.

xxiii, tig. 4 ; pi. xxvi, tig. 4.

1867. Productus, Hall. Palaeontology New York, vol. iv, p. 146.

1867. Productm, Hall. Twentieth Rept. N. Y. State Cab. Nat. Hist , p. 245.

1868. Productus, McChesney. Trans. Chicago Acad. Sci., vol. i, pp. 24-27, pi. i, figs. 7-11; pi. vi, fig. 1.
1868. Productus, Meek & Worthen. Geol. Surv. Illinois, vol. iii, ]i. 528, pi. xx, tig. 7.

1870. Producta, A. Winchell. Proc. American Philos. Soc, vol. xii, p. 249.

1871. Productus, Meek. Palaeontology Eastern Nebraska, pp. 159-169, pi. i, tig. 14; pi. ii, tigs. 2, 5,

6 ; pi. iv, tigs. 5, 6 ; pi. v, tigs. 6, 7, 11, 13 ; pi. vi, tigs. 6, 7 ; pi. viii, tigs.
6, 9, 10, 13.
1873. Productus, Worthen. Geol. Sui-v. Illinois, vol. v, p. 569; pi. xxv, fig. 9.

1873. Productus, Meek & Worthen. Ibidem, p. 569, pi. xxv, tigs. 8, 10, 13.

1874. Productus, Derby. Bull. Cornell Univ., vol. i, pp. 47, 49, 51, 54, 56, 59, pi. i, figs 2, 10-13. 15;

pi. ii, tigs. 14, 17; pi. iii, figs. 20, 41-44, 46-49; pi. iv, tigs. 1-4, 7-11, 13,
16; pi. vi, tigs. 1, 4-7, 9, 17, 18; pi. vii, tigs. 5-7, 15, 16; pi. ix, tigs. 12, 13.

1875. Product-US, Meek. Paleontology Ohio, vol. ii, p. 282, 283, pi. x, tigs. 3, 4.

1875. Productus, White. Wheeler's Geogr. and Geol. Surv. west 100th meridian, pp. 83, 109-116, 120,

pi. V, tig. 6 ; 111. vii, figs. 1, 2 ; pi. viii, figs. 1-6.

1876. ProductvAS, Meek. Bull. U. S. Geol and Geogr. Surv. Terr., vol. ii, p. 354, pi. i, fig. 1.
1876. Productus, Derby. Bull. Mus. Conip. Zool., vol. iii, pp. 280, 281.

1876. Productus, Newberry. Rept. Macomb's Expl. Exped. from Santa Fe to junction of Gr.aud and

Gi'een Rivers of the Great Colorado of the west.

1877. Productm, Hall & Whitfibld. U. S. Geol. Expl. 40th Parallel, vol. iv, pp. 265-268, pi. v,

figs. 3-12.

1877. Productus, Meek. Ibidem, pp. 64-67, 69, 72-76, pi. vii, tigs. 3-8 ; pi. viii, tigs. 2-4.

1878. Productus, Dawson. Acadian Geology, third ed., pp. 296, 297.

1880. Productm, White. Proc. U. S. Nat. Mus., p. 46.

1881. Productus, White. Tenth Ann. Rept. Indiana State Geologist, p. 148, jil. viii, figs. 7, 8.

BRACHIOPODA. 323

1882. Produetus, Whitfield. Bull. Ainfir. Mus. Nat. Hist., vol. i. No. 3, pp. 46, 47, pi. vi, figs. 6-12.

1882. Productm, White. Eleventh Ann. Rept. Indiana State Geol., p. 373, pi. xlii, fig-s. 1-3.

1883. Produetus, Hall. Twelfth Ann. Rept. Indiana State Geol., pp. 32"), 32(5, pi. xxix, tig-s. 6, 7.
1883. ProductvJi, Hall Rept. N. Y. State Geol. for 1882, plates (xviii) 49 ; (xix) iiO.

1883. Productics, White. Twelfth Ann. Rept. U. S. Geol. Surv. Terr., p. 132, pi. xxxvi, fig-. 1.

1884. Produetus, White. Thirteenth Ann. Rept. Indiana State Geol., pp. 122-126, pi. xxiv, figs. 1-11 ;

pi. XXV, figs. 1-5 ; pi. xxvi, figs. 1-3 ; pi. xxvii, figs. 1-3.

1887. Produetus, Herrick. Bull. Denison Univ., vol. ii, pp. 47-49, pi. ii, figs. 25-30.

1888. Productui, Herrick. Ibidem, vol. Hi, pp. 31-34, pi. i, figs. 24, 26 ; pi. iii ; figs. 20, 22-24 ; pi.

vii, figs. 11, 20 ; pi. x, fig. 6, vol. iv, pp. 19-23, pi. iii, figs. 15, 17, 19 ; pi.
X, figs. 24, 25 ; pi. xi, figs. 26, 29.
1888. Producttis, Keyes. Proc. Acad. Nat. Sci. Phila., Extract, pp. (!, 7.

Our knowledge of the generic characters of this group has not greatly pro-
gressed during the last forty years. Though with the advance of investigation
the specific representation of the genus has become enormous,* the generic
value of Productus was nearly as well understood, if not so closely restricted,
at the date of the elaborate discussions of the genus by de Vernedil (Geologic de
la Russie, etc., 1845), and de Koninck (Monographic du genre Productus, 1847),
as at the present time. The generic divisions which have been since proposed
for species then referred to Productus seem to have but limited value or to
represent no fundamental variation from the type of the old genus. The fol-
lowing diagnosis can not, therefore, vary materially from those given by earlier
writers.f

Diagnosis. Shell free, concavo-convex, the valves usually produced anteriorly;
outline semicircular, sometimes transversely elongate. Pedicle-valve convex,
sometimes geniculated, occasionally with a median sinus. Cardinal extremities
frequently auriculate. Umbo inflated, with apex incurved. Hinge-line straight,
cardinal area and teeth absent or rudimentary. External surface usually with
more or less prominent radiating ribs which are crossed, especially in the
umbonal region, by concentric lines or wrinkles ; rarely smooth or finely striated,
often studded with spines varying in size and abundance. These spines are

* De Koninck desciibed sixty-one sjiecies in his Monograph in 1847, not recognizing the genus Stropha-
LOSIA, King, 1844, nor indicating the various subdivisions which subsequent writers have erected into genera
or subgenera. In Miller's North American Geology and Paheontology (1889) eighty species of Productds
and twenty-seven species of Productella are given as occun'ing in the PaUeozoic rocks of this continent
alone.

t Waagen, after his elaborate study of the species of the Productus limestone of India (1884), says:
" I have nothing new to aild to them [the generic characters]."

324 PALMONTOLOGY OF NEW YORK.

frequently scattered irregularly over the surftice, generally strongest and dis-
posed with greatest regularity upon the cardinal extremities, and sometimes oc-
curring only in this region. They are hollow and appear to have communicated
with the interior cavity of the shell. On the interior of the valve is a narrow
median ridge, separating the two dendritic impressions of the adductor muscles;
outside and in front of these are two broadly Habellate, longitudinally striated
scars of the cai'dinal muscles. In the pallial region are sometimes found traces
of spiral cavities, which were occupied by the tleshy arms.*

The brachial valve is operculiform, more or less concave or .almost flat over
the visceral area. Cardinal area, sockets and crural plates absent or rudi-
mentary ; cardinal process strong, curved or erect, extending far above the
hinge-line ; its inner face is divided into two lobes by a longitudinal furrow,
and each of these parts is deeply divided at its extremity, giving the process
in this aspect a quadrilobed appearance. As viewed from the posterior or outer
face it is strongly trilobed, the inner members of the lateral lobes coalescing to
form a very prominent apophysis. The process is continued over the interior
of the shell as a longitudinal septum, dividing the impressions of the adductor
muscles. The latter are strongly dendritic and rarely divisible into anterior
and posterior elements. The brachial ridgesf take their origin from near the
post-lateral margins and nearly enclose a sub-circular, smooth or granulose
area. The internal surface of this valve is strongly postulose, and in the
pallial region frequently spinous.

* See Davidson, British Cai-buuilerous Brachiniiotla, j>l. xxxvii, tiff. 1. IStJl.

t Waagen says (Productus-limestone Fossils, p. 611): "A passage in Professor Nedmayr's paper
[Neues Jahrbuch fiir Mineralogie, 1883, vol. ii, p. 27], which is of very great impoitance, I must quote here
more in detail. He says, a chief olijection of Davidson's against the opinion that these ridges form a part
of the brachial apparatus is the existence of spiral impressions which are to be found in the ventral valve
of some specimens of Pkoductus, and which beyond any doubt are impressions of the spiially enrolled ai'ms
of the animal. Now, as tliese impressions show not the slightest accordance with the brachial ridges [reni-
form impressions], Mr. David.son concludes that these latter cannot be taken as belonging to the brachial ap-
paratus. 'I cannot concur,' says Professor Necmayh, 'in this argument. The greatest number of the now
living Brachiopods have arms showing a double curve ; and if such were, as is probable, present in Pro-
DUGTBS, these features (the ridges in the one and the spiral impressions in the other vahe) are in no way
difficult to explain ; on the contrary they indicate very accurately the direction and the manner in which the
arms extended in Productus. They run first along the descending, then along the reascending branch of
the ridges, were then bent back over the descending branch, and curled in a spiral coil, which caused the
impression in the ventral valve. Thus, in their general shape, these arms very nearly agree with those
occurring in Tbrbbratdla and Waldhbimia, though in proportion and direction of the different parts certain
diffei-ences exist.' This deduction is of very great systematic importance."

BRACHIOPODA. 325

Shell substance fibrous, strongly punctate.

Type, Produdus Martini, Sowerby, =^ Anomites producfus, Martin, = Anomites
semireticulatus, Martin, i= Produdus semireticulatus, Martin. Lower Carboniferous
limestone to Coal Measures.

Observations. It is the usage of sojne systematists to regard the genus
Productus as a starting point in the classification of the articulate brachiopoda
on account of the usual absence of the cardinal area and teeth. These are
features which are unquestionably in an obsolescent condition. It is rarely,
however, that some trace of them is not discernible, and it has been observed
by various writers, that they are sometimes well-defined, and that too in species
where they are normally wanting. For example, they may be present
in the species Produdus semireticulatus and P. Nebrascensis. In these features
Productus is degenerate, but this degeneracy has apparently not extended to
other points of structure, and the genus certainly lacks the simplicity of plan
in its structure so apparent in Orthis. Its late appearance in the Palaeozoic
and its close kinship to the CnoNETES-stock is evidence of its derivation from
that source. The earliest phase of the productoid type, which is abundantly
developed in the Devonian, and which has been distinguished by the name of
Productella, retains the articulating processes and cardinal area with persist-
ence throughout the period immediately preceding the appearance of normal
Productus. These features are, however, always more or less obscure, and
manifestly approaching desuetude. Leaving for the present the consideration
of this and the other generic or subgeneric divisions, which have been taken
from Productus, we have, in this genus, to deal with a very homogeneous
group of fossils.

A grouping of the species of Productus was proposed by de Verneuil in
1845,* and this was amended and somewhat amplified by de Koninck in 1847. f
Dr. Waagen, in his magnificent treatise on the Producti of the Salt-Range,
is the latest writer who has discussed the genus at length, and has adopted
this classification with some modifications and additions ; it is evident that no

* G^ologie de la Russie, p. 253.

t Monographie du genre Productus, p. 29.

326 PALEONTOLOGY OF NEW YORK.

better means for the arrangement and simplification of this grouj) can now be
offered. Some of tlie divisions made by the French authors must be aban-
doned, since the forms on which they were founded have been advanced to a
generic or subgeneric designation ; namely, the group Laves, de Koninck, which
included P. Leonhardi = Koninckina ; the Proboscidei, de Koninck, for shells like
P. proboscideus, de Verneuil, a group for which CEhlert has proposed the sub-
generic term Proboscidella ; and the Caperati, de Verneuil, a group of Devo-
nian and Carboniferous forms essentially equivalent to Productella. Waagen
has proposed to divide the group Striati, de Verneuil, into the Lineati and
Irregulares.

We have then the following arrangement, with citations of American repre-
sentatives of each group :

I. Lineati, Waagen. Surface covered with fine radiating costae which are
rarely spinous and are not crossed by concentric plications or wrinkles. These
shells are greatly produced and sometimes the anterior margins of the valves
are modified by the development of a fold or sinus (P. Americanus, Swallow, =
? P. (Bquiradiata, Shumard). The shells were very fragile and have usually been
subjected to much distortion in fossilization.

Examples :

P. Cora, d'Orbigny. P. Americanus, Swallow.

P. Prattenanus, Norwood. P. aquicoslaius, Shumard.

P. levicostus, White. P. pileiformis, Newberry.

P. ovatus, Hall. P. nodosus, Newberry.

II. Irregulares, W.aagen. Elongate shells very narrow at the beak, mytili-
form in outline; mode of growth quite irregular. Surface as in the Lineati;
spines grouped almost wholly about the cardinal line.

We are not aware that any member of this group has been recognized in
America. The best known species is P. striatus, Fischer, a widely distributed
form in the Carboniferous limestone of Europe. Waagen has described the
species P. compressus and P. mi/tiloides, from the Permo-Carboniferous of the
Salt-Range.

III. Semireticulati, de Verneuil. The longitudinal ribs are sparsely spinous;
surface of the visceral disc covered with concentric wrinkles.

This group includes the greater number of North American species, but it

BRACHIOPODA. 327

is to be observed that specific distinctions in the group are established with
great difficulty on account of the persistence of the type of structure without
essential modification.
Examples :

P. semireticulatus, Martin. P. Wortheni, Hall.

P. arcuatus, Hall. P. magnus, Meek and Worthen.

P. costatus, Sowerby. P. nanus, Meek and Worthen.

P. Burhngtonmsis, Hall. P. Lasallensis, Worthen.

P. Altonensis, Norwood and Pratten. P. temiicostatus, Hall.

P. Chesterensis, Worthen.

IV. Spinosi, de Verneuil. Surface strongly tuberculose or spinose ; not
reticulated.

Examples :

P. Nebrascensis, Owen. P. scabriculus, Martin.

P. asper, McChesney. P. marginicinctus, Prout,

V. Fimbriati, de Koninck. Surface without radiate strioa or ribs; covered
with concentric ridges or plications, bearing rows of small, thickly set spines.

Examples :

P. puncfatus, Martin. P. alternatus, Norwood and Pratten.

P. vittaius, Hall. P. symmetricus, McChesney.

P. biseriatus, Hall. P. Rogersi, Norwood and Pratten.

VI. Horridi, de Verneuil. Surface without radiating or concentric plications ;
pedicle-valve with a deep sinus. It is doubtful if any member of this group is
known from American faunas. Among European species are :

P. horridus, Sowerby. P. opuntia, Waagen.

P. Geinitzianus, de Koninck.

VII. Mesolobi, de Koninck. Surface without radiating plications, except a
prominent median rib. Unknown in this country.

Examples in the European Devonian are :

P. mesolobus, Phillips. P. Christiani, de Koninck.

;S28 PALEONTOLOGY OF NEW YORK.

Genus PRODUCTELLA, Hall. 1847.

PLATE XVII, FIGS. 1-9, 16-46.

ProducUis ( partim) of eai-lier authoi-s.

1840. Leptwna. J. de C. Sowbrbt. Ti'ans. Geol. Society London, vol. v, p. 704, pi. Ivi, fig. 5.

1840. Product lis (partim), MoROursoN. Bull. Societe Geol. de France, vol. xi, p. 25.5.

1842. Strophomena, VjInoxem. Geol. N. Y. Rep. Third Dist., p. 179.

1842. Strophomena, Conrad. Journ. Acad. Nat. Sci. Phila., vol. viii, p. 25(5, pi. xiv, fig-. 9.

1846. Strophatosia (partim). King. Ann. and Mag-. Nat. Hist., vol. xviii.

1854. Productiu!, Norwood and Prattbn. Jour. Acad. Nat. Sci. Phila., vol. iii, p. 21.

1857. Productus, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist,, pp. 172-180.

1858. Productus, Hall Geol. Surv. Iowa, vol. i, part 2, pp. 498-500, 517, 518, pi. iii, figs. 8-10; pi.

vii, figs. 1, 3, 4.

1860. Productus, Swallow. Trans. St. Louis Acad. Sci., vol. i, p. 640.

1861. Productus, Hall. Fourteenth Rept. N. Y. State Cab. Nat. Hist., p. 99.

1862. Prodiicta, A. Winchell. Proc. Acad. Nat. Sci. Phil., vol. xiv, p. 411.

1863. Prnducta, A. Winchell. Ibidem, vol. xv, p. 4.
1865. Producta, A. Winchell. Ibidem, vol. xvii, p. 114.

1867. Prodiictella, Hall. Paloiontology N. Y., vol. iv, pp. 153-160, 162-184, pi. xxiii, figs. 1-11, 25-49;

pis. xxiv, XXV and xxvi.

1867. Productella, Hall. Twentieth Rept. N. Y. Stace Cab. Nat. Hist., p. 245.

1868. Productus, Meek and Worthen. Geol. Surv. Illinois, vol. iii, p. 412, pi. x, fig. 3.
1870. Productus, A. Winchell. Proc. American Philos. Soc, vol. xii, p. 249.

1872. Productus (Productella), Hall and Whitfield. Twenty-fourth Rept. N. Y. State Mus. Nat.

Hist., p. 198.
1874. Productella, Nicholson. Geological Magazine, n. s., vol. i, p. 118.
1S75. Productus (Productella), Hall and Whitfield. Twenty-seventh Rept. N. Y. State Mus. Nat.

Hist., exj)lanation pi. ix, figs. 9, 10.
1877. Productus, Meek. D. S. Geol. Expl. 40th Parallel, p. 36, pi. iii, fig. 7.
1879. Productella, Rathbun. Proc. Bost. Soc. Nat. Hist., vol. xx, p. 17.

1883. Productella, Hall. Rept. N. Y. State Geol. for 1882, pi. (xvii) 48, figs. 1-9, 16-46.

1884. Prodiictiis (Productella), Walcott. Pal. Eureka Dist., pp. 128-133, 214, pi. ii, fig. 10; pi. vii,

fig. 2 ; pi. xiii, figs. 8, 9, 18-20.

1888. Productus, Herrick. Bull. Denison Univ., vol. iii, pp. 31-34, pi. iii, figs. 18, 28; pi. vi, fig. 16;

pi. vii, fig. 18.

1889. Productella, Nbttelroth. Kentucky Fossil Shells, pp. 69, 70, pi. xvii, figs. 5-9 ; pi. xxvi, fig. 7.

It is a natural presumption that the earlier forms organized on the pro-
ductoid type of structure should retain the cardinal areas and articular pro-
cesses of the valves, and it is upon the natural persistence of these features in
many if not all of the Devonian species that the genus Productella was based.
This group was founded on the Productus subaculeatus, Murchison,* a middle

* This species was identified by M. de Vernbuil as occurring in the American Devonian rocks near
Charleston Landing, Indiana, and the fossil originally figured, as typical Productella, was obtained from
near .Jefferson, in what was then regarded as the Corniferous limestone, but which later investigations have
proved to be the calcareous beds representing the Hamilton group in its western extension. See Pal. N. T.,
Vol. V, pt. ii, p. 139 ; " Note on the Hydraulic Beds and Associated Limestones at the Falls of the Ohio."

BRACHIOPODA. 329

Devonian form, and, as already observed, it is essentially equivalent to
DE Vernedil's division of the Producti caperafi; certain small species which ex-
tend into the earlier faunas of the Carboniferous still retaining the cardinal
area and teeth. It is to be noticed that these features are in all cases obscure
and frequently difficult to discern, but even the large species occurring in the
late Devonian (Chemung) and early Carboniferous (Waverly), and which
resemble more in size and expression the normal species of the later faunas, do
retain them. There is no reliable evidence that Productus, as we have used
the term, occurs in Devonian faunas, and there is little reason to doubt that, in
this country, it does appear as early as the Waverly group (P. Newbernji and
P. semireticulatus).

There are some peculiarities in Productella which may prove of value
in classification. The cardinal process rarely shows a trilobation when viewed
from the posterior face, the bilobate character being about equally developed
on both sides ; the delthyrium is apparently covered on both valves ; the
muscular impressions of the brachial valve are very small, and their surface is
not dendritic ; the brachial ridges or reniform impressions are i-arely retained,
if ever present. The existence of teeth in the pedicle-valve implies the pres-
ence of sockets and crural plates in the brachial valve. The latter are
divergent ridges nearly parallel to the hinge-line, and corresponding to the
thickened ridges lying just within the cardinal margin in most species of Pro-
ductus. The combination of all these features, though they may not be suffi-
cient to give to Productell.a. a thoroughly valid biological basis as a strongly
marked and distinctly limited generic form, may nevertheless serve to con-
tinue the usefulness of the designation in distinguishing certain forms among
the barren mass of Productoid material, where individuality is feebly repre-
sented, or entirely lost in the multitude of forms. With our present knowl-
edge and views of classification it must be regarded that Productella and
Productus are members of a descending series and represent diSerent stages in
the process of degeneration. In the discussion of the characters of Pro-
ductella, given in Volume IV of the Palasontology of New York (p. 151), the
following observation was made : " It appears to me that we have in the De-

330 PALjEONTOLOGY OF NEW YORK.

vonian period the incipient manifestation of the productidian type, which he-
came modified in the later Carboniferous period, where, with conditions
favorable to its excessive development, it has assumed extravagant forms and
proportions, but here and there indicating the character of its prototype in the
presence of an area and foramen, among species of a genus which is character-
ized by the absence of these features. In the still later Permian period, with
changed conditions, we have an approximate return to the earliest forms of the
species, or to the prototype ; and in reality the foundation of the genus lies in
the Devonian forms which have been referred to Strophalosia."

From the Carboniferous ProducU Dr. Waagen proposed in 1884 to separate a
group characterized by a prominent internal ridge situated just within the
margins of the valves. To this group he gave the designation Marginifera,
and described it in the following terms :

" The shells which I consider as belonging to the present genus are always
rather small, and never attain any considerable dimensions. In their external
appearance they are absolutely like Produdus, so long as the shell is not bro-
ken, but as soon as the shell-margin is removed, which very easily happens,
the difference comes to light. The cause why the shell-margin so very easily
breaks off is a thick, prominent shelly ridge, placed vertically on the internal
surface of the dorsal valve, and by which the visceral part of that valve is girt.
In the ventral valve a similar ridge is developed within the wings only. In
this way the visceral part of the shell is perfectly chambered off from the
remainder of the shell. These prominent concentric ridges are sometimes
finely striated and crenulated ; sometimes smooth. The other internal charac-
ters are in all the specimens at my disposal (except in Marg. typica, W., where
the description will be found) very indistinct, but on the whole they seem to
be similar to those of Produdus.

" This strange chambering off of the visceral part by means of proper pro-
jecting ridges seems to me perfectly sufficient for the generic distinction of
these forms. Certainly it is as well worthy of notice as the existence of an
area in Aulosteges or the like." (Salt-Range Fossils, p. 713.)

BRACHIOPODA.

ool

Fkis. 28-30. Miirijinifera typim, Waagen.
Aftei- Waagen.

The peculiar t'eatures described may perhaps Ije vahd ground for the
proposed subdivision when in their extreme development, as in M.
typica and M. ornata, Waagen (see figures in the worlc cited, plates Ixxvi and
Ixxvii), but an examination of extensive collections shows that these
elements appear, in various stages of development, in different species, from
the middle Devonian upward through the Coal Measures. In all the Amer-
ican species examined, the characters on which this division is founded seem
to be rather in an inceptive condition when compared with Marginifera typka,
and can scarcely be considered as of such organic importance as to warrant the
generic separation of such forms, especially when it will involve a considerable
number of species in which the articulating ajDparatus and all the more essential
characteristics correspond with Productus. Unless applied in a very restricted
sense, this term can scarcely be adopted to designate an altogether reliable
separation from Productus, for it is manifest that many species, possessing
incipient internal characters which show them to be in the line of develop-
ment toward Marginifera can not, on such grounds, be separated from the old
genus, while the number of forms in which these characters described become
fixed and highly developed, are vei'y few.

332 PALEONTOLOGY OF NEW YORK.

Dr. Waagen has taken Norwood and Pratten's species, Productus splendens,
as the type of the group which embraces his typical species, and fitrther has
expressed the opinion that the American species from the Coal Measures be-
long for the greater part to Marginifera. It is extremely doubtful if the
evidence will sustain this assumption though there are certain species of the
Coal Measures, Productus splendens, Norwood and Pratten, P. longispiiius, Sow-
erby, P. Lasallensis, Worthen, which show the characters of Marginifera in
some stage of development.

In the species Productus dissimilis, Hall,* from the middle Devonian of
Rockford, Iowa, and the upper Devonian of New York, similar internal char-
acters are quite strongly developed, especially in the pedicle-valve, and in both
valves the margins of the ridges are more or less distinctly crenulated. While
the species has the cardinal area, teeth and sockets in an exceedingly obscure
condition, the cardinal process is like that of Productella, strongly bifurcated
to its base, and its external surface presents characters rarely met with either
in Productos or Productella, but not uncommon in Strophalosia ; a spinifer-
ous pedicle-valve, and a brachial valve without spines, but covered with con-
centric lamellose ridges.

* Mr. Walcott has pi-oposed to change the name of this species to P. Hallana (Monograph U. S. GeoL
Sm-v., voL viii, p. 130, 1SS4), as de Koninck had used the same term for a Devonian species which is evi-
dently a Proddctslla. Should, however, the American species be referred to MARGiSfiPBRA, its original
designation may be retained.

BRACHIOPODA. 333

Genus PROBOSCIDELLA, (Ehlert. 1887.

1840. Productus, de Verneuil. Bull. Soc. Geol. de Fi-ance, vol. vi, p. 259, pi. iii, 6g. 3.

1841. Clavagella, Goldfuss. Petrefacta GermaniBB, vol. ii, p. 28.'), pi. clx, fig-. 17.

1841. Productus, von Buch. Abhandl. der Konigl. Akad. dei- Wisseiisch. zu Berlin, Theil i, p. 40.

1843. Productus, de Koninck. Descript. Aninmux Fossiles du Terr. Carl), de Belgiipie, p. 11, fig. 4.

1847. Productus, de Koninck. Monogi-aphie du genre Pri)diictiis, p. 62, pi. vi, fig. 4.

1854. Productxis, Norwood and Pratten. Journ. Acad. Nat. Sci. Philadelphia, 2d Ser., vol. iii, p. 10.

18C1. Producttis, Davidson. British Carb. Braehiopoda, p. 1()3, pi. xxxiii, figs. 1-4.

1880. Productus, Davidson. Bi-itish Carb. Brachiopoda, Suppl., p. 311, pi. xxxvi, tig. 13.

1887. Prohoscidella, CEhlert. In Fi.scher's Manuel de Conchyliologie ; Brachiopodes, p. 1277.

Diagnosis. " Valves very unequal ; the dorsal small, concave, operculiforin ;
the ventral larger, convex, furnished with two lateral expansions which bend
downward to meet the margins of the dorsal valve, and an anterior expansion
which is produced forward into a long cylindrical tube, sometimes attaining
twice the length of the shell ; the suture appears on the dorsal side in the
median line. Sometimes instead of a single tube there is a double enrollment
resulting in two distinct tubes. The surface is ornamented by concentric plica-
tions, traversed by fine radiating ribs, which are fiexuous and close together ;
the last plication, and the groove accompanying it, is sharper than the others
and marks the separation of the ventral valve, properly speaking, from its
lateral and anterior expansions upon which the concentric markings are rare,
faintly developed or wholly wanting, while the radiating striae are regularly
continued." (CEhlert, loc. cit.)

Carboniferous limestone.

Type. Productus proboscideus, de Verneuil.

Figs. 31-33. Productus {Proboscid^lla) proboscideus, de Verneuil.
After DE Koninck.

334 " PALEONTOLOGY OF NEW YORK.

Observations. This term has been proposed for the species above men-
tioned, in which the development of the shell is of such an extravagant char-
acter as to have necessarily modified the functions and anatomy of the animal.
Though the internal markings of this species have not been described, it is
probable that they will prove not to vary materially from those of Productus,
and even the external features are but a result attained along a line of develop-
ment represented in such forms as P. striatus, Fischer, P. ermineus, de Koninck,
P. genuinus, Kutorga, and not resting with P. proboscideus, but attaining an ex-
treme in DE Koninck' s species, P. Nystianus, in which the pedicle-valve is de-
veloped into two tubes, one on the frontal and one on the cardinal margin.*
De Koninck has shown that in this last-named species the formation of these
tubes is an accompaniment of decrepitude, and that the early stages of the shell
conform to the normal form of Productus. No thoroughly satisfactory explana-
tion of the function of these enrollments of the shell has been offered.
De Koninck was disposed to regard them as passages for muscular fibers by
which the animal was attached and d'Orbigny considered them as malformations.
The former view requires too radical a modification of the internal anatomy,
and, as to the latter, there can be no doubt that these tubes which are constant,
though variable in form, size and even in number, are altogether normal. The
further suggestion of d'Orbigny that the animal, from its constrained position,
possibly buried in the sediments, was forced to prolong its shell so as to reach
the surface of the sea-bottom, seems reasonable, and met witli the endorsement
of Mr. Davidson.

The group is probably represented in American faunas by the imperfectly
known P. clavus, Norwood and Pratten, from the Carboniferous of Illinois, a
form which seems to be a close ally of the P. proboscide.us of Visr and York-
shire.

* See r>E Koninc;k'.s tij^urcs of all these species; Moniigr. g-enre Pi-oiliictus, pis. i, vi, xiv.

BRACHIOPODA.

335

Genus ETHER IDGINA, (Ehlert. 1887.

187G. Product IIS, Etheridge, ih. Quart. Jouni. Geol. Society, vol. xxxii, p. 4."i4, jil. xxiv. titrs- 1-14 >

1)1. XXV, figs. 1.0-24.
1878. Prodiictiis, Etheridge, jr. Quart. Jourii. Geol. Society, vol. xxxiv, p. 4'J8.
1880. Prodrutus, D.widson. Monog-r. British Carb. Bracli. Suppl., p. 303, pi. xxxv, Wgs. 4-13.
1S87. Etheridgbm, (Ehlert. In Fischer's Manuel <le Conchyliologie ; Brachiopoiies, p. 1278.

Diagnosis. " Shell of very small size, nearly as broad as long, attached to
foreign bodies by the spines of the ventral valve ; cardinal line straight, nearly
equaling the greatest width of the shell ; pallial outline semicircular ; ventral
valve with a small, entire [?] beak ; surface ornamented by concentric flexuous
plications, bearing a few scattered spines : cardinal process quadrifid." —
CEhlert, ut. cit.

Type, Productus compledens, Etheridge, Jr.

Figs. 31-37. Productus [Etherldgina) complectens, Etheridge.
After Etiii;i!IUge.

Observations. This shell was admirably described by Mr. Etheridge in his
paper on " An Adherent Form of Productus " (1876) and presents the interest-
ing combination of distinctive productoid characters (absence of cardinal area,
hinge, etc.), with a mode of growth characterizing the genus Strophalosia.
The very small shells of this genus, which is thus far represented by the type
species only, have been found adhering to crinoid columns and fragments of
bryozoa; that is, to surfaces of little expansion; hence the creeping spines
appear to effect an attachment by encircling or hugging their host. This ap-
pearance is somewhat deceptive ; the surface of the pedicle-valve is itself
adherent, and the mode of growth of both shell and spines the same as that
already observed in some of the small species of Strophalosia {S. radicans.

336 PALEONTOLOGY OF NEW YORK.

S. scintilla, S. Keokuk) which have usually been found attached to flatter sur-
faces.

Mr. Etheridge makes the following interesting observations on these
fossils :

" When the organism to which the Productus is attached is of larger size
than the latter, the whole of the ventral valve is applied to it, the spines
spreading out and around on each side ; but when the foreign body is of less
diameter than the Productus, as is usually the case with fragments of Polyzoa,
several of the spines are wound tightly round, especially near the beak, and
the reuuiinder of the valve remains free. Attachment took place during the
life of the Crinoid ; for in nearly every case where the Productus remains
adhering, we find that its rate of growth was less than that of the Crinoid, the
result being that the substance of the latter surrounded or enclosed its parasite,
first the encircling spines disappearing and gradually the shell. We have
specimens showing this remarkably well in all stages of the process, from the
mere absorption of the spines by the substance of the Crinoid, up to the total
disappearance of tlie Productus itself, when the Crinoid stem tissumes a swollen
or distorted appearance. From a consideration of this gradual absorption by
the Crinoid stem there arise two questions: Did the Productus when once
attached lose the power to free itself ? or, Did the absorption by the Crinoid,
contrary to the view indicated previously, commence only after the death of
the Productus?"

Some of Mr. Etheridge's figures of this species, which is from the Lower
Carboniferous limestone of Edinburghshire, Scotland, are here reproduced.

BRACHIOPODA.

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Lower Cambrian,

Middle Cambrian.

Upper Cambrian.

Calciferous.

Cliazy.

Trenton.

Utica.

Hiirlsoii Hiver.

Clinton.

Niagara.

Lower lleklerberg.

Oriskany.

Upper Helderberg.

Hamilton.

Chemung.

Waverly.

Burlington.

Keokuk.

St. Louis.

Kaskaskia,
Chester.

Lr. Coal Measure.'?.

Middle and Upper
Coal Measures.

Permian.
Triassie,

Lept^sxa, Daliiiaii,
Rafinesquina, - - -
Stropheddonta, Hall,
Pholidostrophia, -
Lkptustrophia, -
Brachyprii'N, Slialev,
Doivii.LiNA, Gililert, -
Strophonella, Hall, -

Amphistrophia, -
Leptella, - - - -
Plectambonites, Pander,
Uhristiania, - - -
Leptsnisca, Beecher,
Uaviusonia, Bducliaid,
Chonetes, Fischer, -

Anoplia, . - -

Chonetixa, Krotdw,
ch0n08tr0phia, - - -
Chonopkctus,
Chonetei.i.a. Waagen,
Strophalo.sia, King,
Daviesiella, Waagen,
Adlosteges, von Helniersen,
Productus, Sdwerby, -
Productella, Hall.
Maroinifera, Waagen,
Proboscidella, CEhlert, -
Etheriuoina, (Ehlert,

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Permian of Russia.

Upper Carboniferous of India.

Coal Measures of Europe.

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Coal Measures of Europe.

BRACHIOPODA. 337

SUPPLEMENTARY NOTE ON THE GENUS OBOLUS, VON EICHWALD.

The preceding discussions of the inarticulate genera (ending on page 184)
were received from the printer in March, 1890. Since that date an impor-
tant contribution to our knowledge of the genus Obolus has been made by
A. MiCKWiTZ,* whose studies are based upon finely preserved material from
Joafall, near Jegelecht, Esthonia.

Students of the brachiopoda will appreciate the author's statement that "this
genus, notwithstanding the exceeding abundance of its shells in the upper layers
of the Ungulitensandstein of our Cambrian foi"mation, from Baltischport to the
banks of the Sjas, and in spite of its early discovery, has been hitherto as good
as unknown." The details of the internal structure of both valves are worked
out with such a degree of elaboration, that we can do no less than give in
this place the author's diagnosis of the genus and copies of his accompanying
illustrations, observing that the genera Aulonotreta, Kutorga, and Schmidtia,
Volborth, are here regarded as synonymous with Obolus :

" Shell nearly equivalve, equilateral, depressed or slightly convex ; outline
circular or somewhat elongate longitudinally or transversely, in some species
subtriangular or elongate-quadrate.

" Shell-substance calcareo-corneous, structure laminated ; surface lustrous,
with concentric and radial striae varying to deeply incised transverse folds and
radial ribs. Color of the shell dark greyish-blue to black; when in process of
decomposition, whitish to dark brown-red. Anterior and lateral margins thin,
sharply angled and fragile, lying in the plane of the greatly thickened cardinal
margin. The cardinal area lies in the plane of the margins, in the larger valve
being somewhat triangular on account of the elevation of the beak, and divided
equally by the pedicle-groove ; in the smaller valve rounded at the apex, and
in both striated parallel to the base, and grooved from apex to base by the

* Voilaufiye Mitlheilung iiber da.s genus Obolds, Eichwald: Melanges geologiques et iialeontolcgiqiies
tires du Bulletin de rAcademie Impei-iale des Sciences de St. Petei'sbourg, Tome I. (Read October 9th, 1890.)

338 PALAEONTOLOGY OF NEW YORK.

more or le.ss divergent marks of the impressions of the lateral sliding muscles.
The middle portion of the thickened margin slopes to the center of the shell,
forming in the larger valve a line concave as to the beak, and in the smaller
valve a sinus. The lateral portions of the thickened area merge gradually into
the thin margins of the valves. Beneath the hinge-line in both valves is a
narrow median septum, fainter in the small valve, and in both a scarcely visible
ridge discernible only in oblique light. On eitlier side of the septum begins a
furrow which increases in depth and passes through the thickened area in a line
parallel to the margins of the shell.

" The impressions of the vascular trunks of the mantle are continued from
these furrows into the anterior portions of the valves and parallel to their
margins. Secondary vascular sinuses radiate in great numbers from the main
trunks toward the margins and center of the shell.

" In the median line of the larger valve, between the median septum and the
anterior margin of the thickened cardinal region, lies a deep cordate pit, having
its apex directed toward the anterior margin of the shell and with a shallow
median furrow. In the sinus of the smaller valve is a faint median swelling,
extending beyond the center of the shell and divided longitudinally by an
obscure groove.

" Muscular imjjressions in five pairs for each valve; two of the adductors and
three of the sliding nmscles. The impressions of the adductors lying difectly
beneath the cardinal margin, are separated in the larger valve and in juxtapo-
sition in the smaller. The anterior pair in the larger valve lies on either side
of the cordate pit, in the smaller at the apex of the corneous callosity, extending
into the middle of the valve and forming the sinus. Of the sliding muscles
there is a pair on each side of both valves, close to the cardinal margin and
between the lateral furrows and the margins of the shell. In the larger valve
these scars are in juxtaposition, but in the smaller they are further apart,
touching only at their extremities. The third pair of these impressions in
the larger valve lies close against, but outside the anterior adductors ; in
the smaller valve on either side of the anterior extremity of the median
swelling, in the sinus, and nearer together than the scars of the anterior ad-
ductors. The scars of the paries passes closely about the muscular impres-
sions, crossing both lateral furrows and terminating in the central portion of
the cardinal mar";in."

BRACHIOPODA.

339

I. *

Larger valve. Smaller valve.

Figs 38, 39. Diagrammatic view of Obolits Quenstedii. After Mkkwitz.
a, Pedicle-groove; b, impression left by the advance of the' lateral sliding muscles; c, median septum; rf, cordate pit;
c, sinus; /, median groove; g, median swelling; h, lateral grooves; i, impressions of vascular trunks; k, inipressious of
secondary sinuses; I, impressions of posterior adductors; m, impression of anterior adductors; n, impressions of eliding
muscles; o, outline of splanchnocccle; I, .'iplanchnocctle; II, brachioctHle; III, pleurocojle.

According to this diagnosis, the analogies of Obolus, with Lingula are at
once striking, though there are important differences. In L. anatina there are
four pairs of lateral or sliding muscles, while there appear to he but three in
Obolus Quemtedti ; according to Mickwitz the anologue of k (middle lateral in
Lingula, see figure on page 10), being absent in the latter. The adductors are
the same in number in both, though there is considerable difference in their
disposition ; the position of the posterior band, which is divided at its ventral
insertion being the same as that of the great umbonal in Lingula. In Lingula,
again. King has shown that one of the transmedian bands is divided, which
does not appear to be true of Obolus Quenstedti.

It must be observed that these results have not been obtained from the type-
species of the genus, Obolus Apollinis, von Eichwald, but from a hitherto unde-
scribed form. Experience has taught us that the greatest care is required in
the discrimination of generic values among the oboloid genera of the early
palaeozoic faunas, and it may be a question for subsequent determination whetlier
a species showing so many important differences from the structure hitherto
known in 0. Apollinis should be regarded as congeneric with it. Attention is
called to the similarity in many points of structure of 0. Quenstedti with the
genus Obolella, Billings, as shown in the figures on Plate II of this volume.

340 PALEONTOLOGY OF NEW YORK

DESCRIPTIONS OF NEW SPEGIES FIGURED IN THIS VOLUME.

Orthis? Saffordi, sp. nov.

PLATE V A, FIGS. 38-4U.

Shell semielliptical in outline ; valves subequally convex, the pedicle-valve
being the more elevated at the apex. Hinge-line long and straight, giving
the shell a strophomenoid appearance. Cardinal area low ; delthyriura un-
covered.

Surface covered with numerous rounded, sharply elevated striae, increas-
ing by intercalation, and crossed by exceedingly fine concentric lines.
The details of the interior are not known, but the relations of the shell to
Orthis are demonstrated by the open delthyrium and simple cardinal pro-
cess, slightly lobate on its posterior face.

Length of the type specimen, 17 mm. ; width along the hinge, 22 mm.

Trenton horizon. East Tennessee.

Orthis ? Holstoni, Safford.

I'LATE V A, riUS. 35-37.

Shell transverse ; outline semicircular. Hinge-line long and straight. Pedi-
cle-valve with a high, vertical, cardinal area, transected by a very broad,
uncovered delthyrium ; beak not incurved ; surface sloping evenly toward
the margins, slightly rounded in the median line, and faintly depressed
toward the cardinal angles. Brachial valve depressed convex, nearly fiat,
with a broad and low median sinus.

Surface of both valves covered with fine, elevated, radiating striae, crossed
by faint, concentric, cancellating lines which have a slight retral bend on
the striae.

This shell has very much the aspect of a Clitambonites, but of the two
specimens examined, neither has evidence of a deltidium, and a trans-

BRACHIOPODA. 341

verse section across the umbo of one, shows that the dental lamellje, though
strong and convergent, did not unite to form a spondylium. Received from
Professor Safford.

Trenton horizon (Glade limestone). Near Nashville, Tennessee.
Orthis (Pl^siomys) lokicula, sp. nov.

PLATE Va, figs 3>-S4.

Shell strophomenoid in outline ; reversed convex. Hinge-line long and straight
making the greatest diameter of the shell. Cardinal areas narrow, subequal.
In the pedicle-valve the delthyrium is covered by a convex plate extending
for one-half its length ; the area is erect, the beak not prominent. The
valve is slightly convex in the umbonal region but is depressed outward in
all directions, most strongly in the median line. The brachial valve is de-
pressed about the beak, convex over the pallial region and divided in the
median line by a shallow sinus. The interior characters of the valves are
essentially the same as those in Orlhis subquadrata.

External surface covered with numerous fine, elevated striae, alternating
in size and crossed by finer concentric lines.

Length of an average specimen, 18 mm. ; width, 21 mm.

Trenton horizon. Fountain, Minnesota.

Orthis (Dalmanella) arcuaria, sp. nov.

PLATE Vc, FIGS. 20, '2L

Shell with a general similarity to that of Orthis elegantula, Dalman, but having
the marginal outline more circular, the pedicle-valve more evenly convex,
the umbo more prolate, and the brachial valve considerably more convex.
The pedicle-valve bears a broad fold, and the brachial a shallow sinus, in the
median line. In the interior of the pedicle-valve the muscular area is elon-
gate and very deeply impressed, the umbonal portion of this valve being
considerably thickened.

342 PALEONTOLOGY OF NEW YORK.

Surfiice covered with numerous very fine radiating striae.

Length of the type specimen, 19 mm. ; width, 18 mm. ; depth, 9 mm.

Hudson River group. East Tennessee.

Orthis (Dalmanella) superstes, sp. nov.

PLATE Vc, FIGS. 44-47.

Shell of small size and having the general form and expression of O. hyhrida
Sowerby. Hinge-line short, beaks but slightly elevated. Marginal outline
varying from siibquadrate to subcircular. Valves about equally convex. In
the pedicle-valve the beak is somewhat inflated and slopes evenly in all
directions for nearly one-half of the shell ; from this point onward is a broad,
low median sinus, which is most conspicuously developed in old and gibbous
shells. In rare instances there is a low elevation in the bottom of this sinus
The opposite valve also bears a median sinus which takes its origin at the
beak. In the interior of the pedicle-valve the muscular area is sharply de-
fined, subquadrate in outline, the adductor scars small and the diductors well
developed. In the brachial valve the cardinal process and crural plates are
prominent ; the muscular area well defined and quadruplicate.

The external surface of the valves is covered with fine, elevated strife, of
which twenty of the coarsest reach the beak ; this number increasing by
intercalation to about fifty at the margin. Near the margin very fine
concentric striae are visible.

Length of a normal individual, 12 mm.; width, 13 mm.; depth, 9 mm.

Chemung group. Near Howard, Steuben county, N. Y.
Orthis (Rhipidomella) Oweni, sp. nov.

PLATE VI, FIGS. 19-21.

Shell having somewhat the outline of O. Vanuxemi, but more elongate trans-
versely and gently sinuate or emarginate on the anterior edge. The shells
are usually flattened, but where the form is retained the pedicle-valve shows
a hinge-line whose length is somewhat less than one-half the transverse

BRACHIOPODA. 343

diameter of the shell. The beak is acute, the umbo full but not conspicuous.
x\long the center of the valve is a broad, low sinus, frequently very in-
conspicuous. The interior of this valve is characterized by the relatively
small area covered by the muscular scars, a feature in which it resembles
0. Peloris of the Schoharie grit. The pallial region is pitted or covered with
laint, closely anastomosing ridges. On the brachial valve the median sinus
begins at the apex and becomes very pronounced as it widens anteriorly.
From the ridges forming its lateral margins the surface slopes rather abruptly
and without much curvature. On the interior the cardinal process and
crural plates are not prominently elevated ; the muscular area is small,
quadripartite, the lateral pairs of scars being separated by a broad, thick
ridge.

Surface of both valves covered b}^ a great number of fine radiating, hollow
stride, from 110 to 130 in number, which are crenulated by minute con-
centric lines and crossed at intervals by coarser lines of growth. The
surface was originally covered with short spinules, which are rarely pre-
served. This shell has heretofore been commonly referred to Orthis
Michelini, Leveille.

Keokuk group (Knobstone formation). Button-mould Knobs, Kentucky.
Orthis (Schizophoria) senecta, sp. nov.

PLATE VIA, FIGS. 23, 24.

Shell subquadrate or transversely elliptical, resupinate, unequally biconvex.
The pedicle-valve is depressed convex in the umbonal region and develops
a broad, low median sinus toward the anterior margin. The brachial valve is
the more convex and slopes evenly toward the lateral margins, the median
region being rendered slightly more prominent by an obscure fold.

Internal markings as in other members of Schizophoria.

External surface covered with fine, subequal, closely covered radiating strite.

Length of a typical example, 17 mm.; width, 21 mm.

Clinton group. Reynale's Basin, Niagara county, New York.

344 PALEONTOLOGY OF NEW YORK.

Strophomena Conradi, sp. nov.

PLATE IX A, FIG. 3 ; AND PLATE XX, FIGS. 3-2, 33.

Shell semiovate in outline ; hinge-line straight and forming the greatest
diameter of the shell. Cardinal area narrow on both valves; broader on the
pedicle-valve and but slightly elevated at the umbo. Delthyrium covered ;
deltidium perforated at the apex. Pedicle-valve convex in the umbonal
region, but becoming deeply depressed and concave over the middle of the
shell and again elevated about the margins. The depression of the valve is
most conspicuous along the median line and on the anterior margin where it
produces a subnasute extension. The brachial valve is flat or slightly con-
cave at the umbo, becoming convex over the pallial region ; it reaches its
greatest convexity at about the middle of the shell and is thence deflected
gradually in the median line and more abruptly on the lateral slopes.

Surface of the shell covered with radiating striae, arranged in fascicles
of 4 to 7 fine ones between each pair of coarser ones There are no con-
centric rugsB on either valve, but the radiating stria3 are crossed by ex-
ceedingly minute concentric lines.

Width of the original specimen along the hinge, 23 mm. ; greatest length,
19 mm.

Trenton limestone. Jacksonburg, N. Y.

Strophomena Winchelli, sp. nov.

1883. Strophomena nutans. Hall. Rept. State Geolog^ist N. Y. for 1882, expl. pi. (ix) 39, figs. 10, 12-14.
PLATE IX, FIGS. 10, 12-U ; PLATE XX, FIG. 26.

Shell elongate semiovate ; strongly convexo-concave. Hinge-line straight and
making the greatest diameter of the shell. Cardinal angles sometimes ex-
tended. Pedicle-valve with a moderately broad area arid deltidium; apex
slightly elevated, the valve becoming deeply concave over the pallial region
and reflected at the margins. The teeth are strong and divergent, and from
their bases extend elevated curving ridges which form the margin of the
subcircular or subovate muscular area. Diductor scars broad, enclosing an

BRACHIOPODA. 345

elongate and narrow adductor. Within the anterior and hiteral margins of
the valve is a thickened ridge which is crossed by branches of the vascular
sinuses. Brachial valve tlat in the umbonal region, very convex over the
median portion and sloping gradually to the margins. The cardinal process
consists of two slender and short apophyses which are united at their base
with the crural plates. The latter are very divergent and extend in a broad
curve subparallel to the hinge-line. The muscular scars consist of two pairs,
the posterior being broad and striated, the anterior narrow and close to the
median line. The members of the pairs are separated by a low median ridge.
Surface of the shell covered with numerous very fine filiform striae, regu-
larly but not conspicuously alternating in size. Delicate concentric striae are
sometimes discernible.

Trenton horizon. Clifton and Janesville, Wisconsin.
This shell has been referred to the Hemiprnnites nutans, James (Meek), of
the Hudson River, group which it resembles in its general expression. It differs
from that species in its internal characters and more finely and abundantly
striated exterior.

Orthothetes desideratus, sp. nov.

PLATE rx A, FIGS. -26, 27.
18S3. Streptm-hynchit.1, sp. ^ Hall. Rept. State Geologist N. Y. for 1882, pi. (xi a) 42, figs. 26, 27.

The original specimens of this species are internal casts of a form with a sub-
circular marginal outline, very gibbous brachial valve which has its greatest
convexity central and slopes evenly to the margins, though with a slight
tendency to depression toward the cardinal extremities ; a strongly and reg-
ularly concave pedicle-valve, elevated at the beak and about the margins.
The cardinal area on this valve is moderately high and erect, the hinge-line
being slightly shorter than the greatest diameter of the valves. The sur-
face of both valves is covered with numerous fine radiating striae. The
general form and contom' of the species is very similar to that of Orthothetes
umbraculum of the Eifel.

Waverly group. Medina county, Ohio.

346 PALEONTOLOGY OF NEW YORK.

Derbya ruginosa, sp. nov.

PLATE XIA, FIGS. -IS-Tt.

Shell subelliptical in outline. Hinge-line short, its length being about two-
thirds the greatest diameter of the shell. Pedicle-valve shallow ; cardinal
area moderately high, its lateral slopes being slightly more than one-half the
length of its base ; apex scarcely prominent ; surface depressed or flat in the
umbonal region, becoming irregularly concave anteriorly. Entire valve very
irregular in growth, with concentric ridges and furrows. Brachial valve
very convex ; apex depressed, but the umbonal region gibbous, the greatest
convexity being reached at the center of the valve. This valve is also of
irregular growth, though the irregularities are not so strongly developed as
on the opposite valve. The original specimen is an internal cast in chert
to which portions of the inner laminge of the shell adhere. There are evi-
dences of a flabellate muscular scar on the pedicle-valve and a short ovate
muscular area in the brachial valve.

The traces of the surface striae preserved show them to have been very
fine and numerous.

Keokuk limestone. Nev) Providence, Indiana.
This species is similar in some general respects to Derbya Broadheadi, but
differs in its narrower and lower cardinal area, less convex umbo on the brachial
valve and in the absence of a median sinus on this valve. It may be compared
with the Streptorhynchus crenistria, var. senilis, Phillips (Davidson), from the lower
Carboniferous of Great Britain.

Derbya? costatula, sp. nov.

PLATE XlB. FIGS. 16, 17.

Shell small, outline semi-oval. Hinge-line nearly equal to the greatest diameter
of the valve. Cardinal area moderately high, with a prominent deltidium
very wide at the base. Pedicle-valve with an elevated beak from which the
surface slopes to the margins with a tendency to irregular growth. Brachial
valve faintly depressed at the umbo, but otherwise pretty regularly convex,

BRACHIOPODA. 347

the most elevated point being a little behind the middle of the valve. There
is faint median sinus over the anterior region.

Surface marked with a few coarse radial ribs, between each two of which
are implanted one, two or three much finer ones. These ribs are crossed by
a few distinct concentric varices of growth.

Chester limestone. Crittenden county, Kentucky.
This species is readily distinguished by the character of its surface orna-
mentation, and though the interior features of the shell are as yet unknown, a
very closely allied form from the upper Coal Measures near Kansas City has a
well developed median septum in the pedicle-valve, and is hence to be referred
to the genus Derbya.

Derbya Broadheadi, sp nov.

PLATE XIA, FIGS. -23, 24.

Shell with irregularly suboval marginal outline. Hinge-line short, its length
not exceeding, and usually less than one-half the greatest diameter of the
valves. Cardinal area of the pedicle-valve high, sometimes regularly tri-
angular, often distorted or somewhat incurved ; deltidium broad at the base
and rapidly tapering with a faint median groove on its surface. Pedicle-
valve convex in the umbonal region, irregularly rugose and depressed over
the pallial area. Brachial valve very gibbous at the umbo, the greatest con-
vexity being behind the center of the valve. From the umbonal region the
surface slopes evenly toward the lateral and anterior margins, but is more
abruptly depressed toward the cardinal extremities where it forms short sub-
alate expansions. The valve is but slightly unsymmetrical and is bilobed
by a conspicuous median sinus which takes its origin near the umbo, and
widens to the anterior margin.

Surface covered by fine radiating striae which are of subequal size over
the umbonal region, but toward the margin became arranged in fascicles on
account of the addition of finer strise as growth advances. Concentric rugae
and growth-varices are frequent, especially on the pedicle-valve.

Upper Coal Measures. Near Kansas City, Missouri.

348 PALEONTOLOGY OF NEW YORK.

Derbya Bennetti, sp. nov.

PLATE XIA, FIGS. 34-39.

Shell subtrihedral in general aspect, quite irregular in its growth. Hinge-
line short, its extremities on both valves being auriculate. Pedicle-valve
much the more irregular in growth, sometimes retaining the scar of attach-
ment at its apex. Cardinal area unusually high, narrow, erect or slightly
incurved, and frequently distorted ; delthyrium curved. General surface of
the valve depressed-convex in the middle, sometimes rapidly sloping in all
directions, at others concave in the umbonal region ; as a rule very unsym-
raetrical. The brachial valve is deep, more regularly convex and has a full
rounded umbo and a conspicuous median sinus. On the interior the pedicle-
valve bears an extremely high median septum which is united with the den-
tal ridges near the apex. The cardinal process is high, erect and deeply
bilobed, each of its apophyses being strongly grooved on its posterior face.
Other internal characters unknown.

The surface of both valves is covered by fine, elevated, thread-like striae
increasing very slowly by intercalation. The edges of these striae bear nu-
merous minute asperites which may be due to the crossing of fine concentric
lines. Irregular lines and wrinkles of growth are abundant near the margins.

Upper Coal Measures. Near Kansas City, Missouri.

Derbya cymbula, sp. nov.

PLATE XI E, FIGS. 2,3.

Shell large ; marginal outline transversely subelliptical. Hinge-line straight,
its length being al)out two-thirds the greatest diameter of the shell On the
pedicle-valve the cardinal area is high, its base being one-third longer than
its sides, and it may be somewhat unsymmetrical from distortion. Its surface
is finely striated both longitudinally and transversely, and is divided into an
outer and inner portion by two lines diverging from the apex and meeting
the hinge-line half-way between its extremities and the edges of the deltidium.
Deltidium l)road at the base, rapidly narrowing for one-third its length.

BRACHIOPODA. 349

thence tapering more gradually to the apex ; its surface is marked by a well-
defined median groove for its entire extent. The surface of the valve is
elevated in the umbonal region and slopes somewhat irregularly to a low
depression over the pallial region and about the mai-gins. The brachial
valve is broadly concave at the umbo, but rapidly becomes regularly convex,
the greatest convexity being in the middle of the valve, whence it slopes
almost equally in all directions. There is no evidence of a tendency to irregu-
lar growth in this valve.

Surface covered with numerous fine, sometimes irregular striae, increasing
by implantation. Over the umbonal and pallial regions these striae are of
about equal size, but about the margins the tendency to fasciculate arrange-
ment is more apparent. Interior structure, except the existence of a median
septum in the pedicle-valve, unknown.

Upper Coal Measures. Near Kansas City, Missouri.

Derby A affinis, sp. no v.

PLATE XlB, FIGS. 4, 5.

Shell subsemicircular in outline, somewhat transverse. Hinge-line straight
nearly equaling the greatest diameter of the valves. Cardinal area of the
pedicle-valve high, its greatest height being about equal to one-third the length
of the hinge-line ; divided by diverging lines as in the preceding species and
crossed by conspicuous horizontal and fainter vertical striations. This area
is often much distorted. Deltidium having a width at the base equal to one-
fifth the length of the hinge-line ; it tapers evenly to the apex and bears a
median groove on its surface. The umbo is elevated, but the surface of the
valve becomes depressed, irregular in growth and concentrically wrinkled,
though not concave anteriorly. Brachial valve faintly depressed at the apex,
but rapidly becoming convex, the greatest convexity being in the umbonal
region, whence the slope is quite regular in all directions, being somewhat
more abrupt toward the cardinal extremities. This valve also shows a slight
tendency to unsymmetrical growth in the umbonal region.

350 PALEONTOLOGY OF NEW YORK.

Surface covered by sharply defined, sub-equal radiating striae, which in-
crease by implantation. The grooves between these striae are deep, and
both striae and grooves are crossed by fine concentric lines, which on the
former produced a series of sharp asperities. Interior, with the exception
of the median septum in the pedicle-valve, unknown.

Upper Coal Measures. Near Kansas City, Missouri.
There are many points of similarity in the Orthis Kaskaskiensis, McChesney,
from the Kaskaskia limestone, Derbya cymbula and the species under consid-
eration. All have the same general aspect. In 0. Kaskaskiensis the brachial
valve is most convex at the umbo, the pedicle-valve generally concave and the
hino-e-line equal to the greatest diameter of the shell ; in Derbya affinis the
brachial valve also has its greatest convexity at the umbo, but the hinge-line
is considerably shorter than in McChesney's species, and there is a notable
difference in the character of the surfoce striae ; while in Derbya cymbula the
convexity of the brachial valve is greatest at its center, the hinge-line very
short and the pedicle-valve concave or depressed only over the pallial region.

Derbya (?) biloba, sp. nov.

PLATE XI, FIGS. 4, 5.

Shell small, obcordate in outline. Hinge-line short and straight, its length
being considerably less than one-half the width of the shell. On the pedicle-
valve the cardinal area is moderately high and slightly arched backward ;
delthyrium covered. The surface of the valve is somewhat depressed or
flattened over the pallial region. The brachial is deeper and more convex ;
the umbo is full but not elevated, and just in front of the apex there begins
a broad and conspicuous sinus which widens rapidly and renders the shell
bilobate on its anterior margin.

Surface covered with numerous fine radiating striae. Interior unknown.

Upper Coal Measures. Winterset, Iowa.

BRACHIOPODA. 351

Streptorhynchus Ulrichi, sp. IIOV.

PLATE Xlis, FIG. 15.

Shell of comparatively large size for this genus. General contour subtrihedral.
Hinge-line shorter than the greatest diameter of the valves. Cardinal area
high, somewhat incurved and distorted; sides considerably shorter than the
base. Deltidium broad. Marginal outline of the pedicle-valve, from hinge-
line forward, semiovate, somewhat irregular, contracted toward the hinge
and expanding in the pallial region. The interior of the pedicle-valve shows
strong teeth, the dental lamellae extending downward and enclosing the
posterior portion of an ovate muscular scar. There is no median septum.
External surface convex in the upper part becoming depressed toward the
anterior margin; quite irregular in growth, being crossed by more or less
conspicuous concentric ridges or varices ; covered with numerous fine radi-
ating, subequal striaB which increase by implantation.
Brachial valve not known.

Chester limestone. Crittenden comity, Kentucky.

Christiania subquadrata, sp. nov.

18S3. Leptcena subquadrata. Hall. Rept. State Geologist N. Y. for 1882, pi. (xv) 46, tigs. 32, 33.
PLATE XV, FIGS 32,33; PLATE XVa, FIG. 36; PLATE XX, FIGS. lS-20.

Shell small, elongate, semielliptical in outline, strongly convexo-concave.
Hinge-line short, straight, not equaling the greatest diameter of the valves
anteriorly. In the pedicle-valve the umbo is full, rounded and incurved,
with the apex obscure ; the cardinal area is moderately broad and bears an
open delthyrium which terminates above in a circular foramen. The teeth
are short, divergent and continued into ridges which form the lateral mar-
gins of two linguiform, muscular scars, traversing the shell for almost its
entire length. These scars enclose two much shorter impressions. In the
brachial valve the area is narrow, the cardinal process bipartite on its an-
terior face, each of the lobes being grooved behind. The crural plates are
very long and divergent, the upper portion of each terminating in an elevated

352 PALEONTOLOGY OF NEW YORK.

extremity ; the lower portion produced on each side as a strongly elevated
ridge, curving slightly inward on the sides, then outward on approaching
the anterior margin of the valve ; each branch recurving and passing back-
ward, parallel to the median axis, as far as the base of the cardinal process.
The symmetrical spaces thus formed are each divided transversely by a
somewhat lower vertical ridge. Between the inner muscular walls in the
median line is a low, rounded, longitudinal ridge.

The surface is smooth or covered with concentric, usually somewhat squa-
mous lines of growth.

Lower Helderberg group. Perry county, Tennessee.
Lept^enisca adnascens, sp. nov.

PLATK XVa, figs. 22, 23.

Shell small, very irregular in outline ; cemented to shells of other brachiopods,
especially of Orthis, by the entire external surface of the pedicle-valve.
Hinge-line making the greatest diameter of the shell. Cardinal area well
developed on the pedicle-valve and bearing a convex deltidium. Internal
characters as in L. tangens. Brachial valve prominent at the beak, elevated
in the umbonal region and slightly depressed anteriorly. Surface smooth or
witli irregularly concentric wrinkles.

Lower Helderberg group (Shaly limestone). Near Clarksville, N. Y.
LepTjEnisca tangens, sp. nov.

PLATE XVa, figs. 21-3U.

Shell transverse ; hinge-line making the greatest diameter ; contour regularly
convexo-concave ; attached by the apical or umbonal portion of the pedicle-
valve, usually fronds and twigs of bryozoa. Cardinal areas narrow ; del-
thyrium covered. In the pedicle-valve teeth not prominent but continued
into strong, converging lamellae which nearly enclose an oval muscular area;
this area is divided by a median septum. External surface convex ; bi-

BRACHIOPODA. 353

lobed by a more or less conspicuous median furrow. Brachial valve strongly
concave.

Surface smooth, with a few inconspicuous concentric growth-lines, and
faint radiating striae on the inner lamella toward the margins.

Lower Helderberg group (Shaly limestone). Near Clarksville, N. Y.

Chonostrophia Helderbergia, sp. uov.

PLATE XVb. fig. 14.

Shell tenuous, semi-elliptical in outline. Hinge-line straight and making the
greatest diameter of the valves. Valves nearly flat, the pedicle-valve being
gently concave and the brachial correspondingly convex. Cardinal areas
very narrow; marginal spines not observed. Teeth of the pedicle-valve
well developed on either side of the moderately broad delthyrium ;
at their bases arises a median septum, strongest at the point of beginning
and continuing for one-half the length of the valve. In the brachial valve
the crural plates are very short, subparallel to the hinge-line and apparently
coalesced with the short cardinal process. No traces of muscular scars re-
tained.

Surface covered with a great number of exceedingly fine, subequal radiating
striae, all of which are apparent on the interior of the shell, even to the
bases of the teeth and crural plates.

Lower Helderberg group (Shaly limestone). Albany county, N. Y.
Strophalosia Rockfordensis, sp. nov.

PLATE XVUa, riGS. 1-3.

Shell semielliptical in outline, somewhat elongate. Hinge-line scarcely as
long as the greatest diameter of the valves. Cardinal area well developed
on each valve, that of a pedicle-valve bearing a convex deltidium ; scar
of attachment on the pedicle-valve covering only the apical region. Sur-
face regularly convex, depressed toward the cardinal angles ; bearing scat-

354 PALEONTOLOGY OF NEW YORK.

tered spines, of which thei^e is a well-defined row of six or seven on the car-
dinal margin. Thei-e are faint, irregularly concentric wrinkles among the
spine-bases. Apex of the brachial valve convex but the valve rapidly be-
comes concave, being of somewhat less curvature than the opposite valve.
Surface with conspicuous, irregular, concentric corrugations, and a few short
spines over the pallial region.

Length of the original specimen, 9 mm. ; width along hinge-line, 10 mm.

Upper Devonian. Rockford, Iowa.

ERR^T^.

Pag-e 57, line 12 fi-om bottom ; for " Plate I " read " Plate II."

Page 75, line 6; for " jiosition " read "portion.''

Page 83, line 5; for "Leotobolus" read "Leptobolds."

Page 99, line 23; for "and" i-ead "are."

Page 99, line 24 ; insert " which " after " 25-29)."

Page 108, under fig. 60 ; for " pedicle " read " brachial ; " for " brachial " read " pedicle."

Page 139, line S fi-oin bottom ; Shabpe's specimens came from Cincinnati, Ohio, or vicinity, and were
probably examples of the form now known as T. millipunctata. Hall, as Emmons' T. tei-m'malis has not been
found in that locality. Sharps, however, mentioned Emmons' species as the type, and it may be best to
retain the New York form as such.

Page 173, line 4 ; for " Lingula Unr/idiita" read •' Linrjula linguata."

Page 18.'), line IS ; for " Strophodonta " read "Stropueodonta."

Page 194, second pai-agi'aph. The deltidium of Orthis? Laureiithia is minutely perforate.

Page 28S, line 15; dele "are."

Page 303, line 2 ; for " XVa" read " XVb."

Page 308, line 5 ; for " C. undidatus" read " C. undulal.a;" for "C Novascoticus " read C. Nuva-
scotUa." Corrected in part of the edition.

Page 328, line 1 ; for "1847 " read " 1867."

Explanation of Plate I, line 25; inssert "(?)" after "Lingibla Vanhorn'ii, Miller"; line 28, dele; read
" Trenton horizon. Frankfort, Kentucky."

Expiation of Plate IVk, continued, lino 8; for " Orbiciiloidea pidchra" I'ead " Orbiculoidea Hei-zeri."

Explanation of Plate I Vf, line 33 ; for " Orbietdoidea pulvhiu " read " Orbiculoidea Herzeri."

INDEX

TO PALEONTOLOGY OF NEW YORK, VOL. VIII, PAIJT I.

I. Register of Authors' Names.

(These references do nut include names used in .is.sociation witli specific designiitions.)

Abich, II.,
AiJ:assiz, L., .
Aldrovantlus,
Ami, II M., .
Angelin, N. P., .
Arcliiac, E. J. A.
Ast, Ph, .
Barraude, J.,

Barrett, S. J., .
Barrois, C , .
Bayau, P.,
Beeclier, C. E.,

Bergman,
Beuth, F., .
Billings, E.,

D. deSt. S. d'.

253.

36, G8, 73, 78, 7'J, 98, 101, 10.1,

131, H-J, '.'DO, -27-', '273, 274,

. 1-JO. U2,

14(5, 189, im, 209, 254, 272, 273,
291,

3, 27, 33, 36, 40, 41, 44, 4.'), SI), 6li

72, 7.1, 76, 78, 90, 91, 97, 98, 101, 103, 120, 138,

187, 188, 192, 194, 195, 196, 198, 201, 205, 2J8,

221, 230, 232, 238, 242, 244, 245, 253, 269, 276,

285, 286, 288, 290, 294, 295, 298, 303,

Binney, W. G., .

Bittner, A., .......

BlaiuviUe, II. M. 1). de,

Bolten,

Boucharrl,

Bronn, H. G.,

Brooks, W. K., .

BruguiAre, J. G.,

Biich, L, von,

245, 2J6, 247, 249, 260,

Calvin, S.,
Carpenter, W. B.
Ca.stelnau, F. de,
Chemnitz, J. H.,
Clarke, J. M.,

80, 189, 200. 201, 20t, 211,
253, 267, 276, 290, 303,
. 183,

. 187, 200, 250, 276,

3, 121, 146, 189,206,209,254,

277, 290,

Conrad, T. A., . 2, ,56, 59, 186, 187, 192, 196, 198,

204, 205, 253, 257, 276, 280, 281, 284, 290, 295, 303,

Cotton, H., .

. 3, 187,
122,

Cox, E. T., .
Cuvier, G. C. F. D
Da Co.sla, E. U.,
Dall, W. II.,

122,
Dalman, J. \V.,

2, 14, 33, 34, 36, 44. 45, 83, 118,

123, 128, 138, 145, I.iO, 151, 155, 160,

186, 191, 192, 204, 203, 233, 236,

280, 290, 293, 290, 297,

p

VGB.

261,

263

233

186

113,

115

204

303,

317

218

127,

133

2S5,

290

144,

285

285

264,

260

277,

290

300,

301

218

145

. 67,

70

142,

145

211,

217

281,

284

304,

311

246

298

232,

279

2

301

, SO,

186

162

2

321

22l',

233

321,

333

206,

285

149

281,

303

321

272,

273

291,

301

200,

201

321,

328

252

211,

264

145,

150

321

120,

121

236,

277

276,

277

303,

321

U.-ina, J.D,,

Davitlson, T.,

21, 22, 27, 31, 33, 34,
51,53, .56,57,53, 62,
90,91, 91, 98, 100,
115, 120, 122, 125,
147, 148, 149, 150,
193, 200, 201, 202,
241, 242, 213, 245,
264, 267, 26S, 269,
286, 290, 295, 296,

Uawson, J. W.,
Derby, O. A.,

Defrance,
Dunieril, A.,
Dwiglit, W. B.,
Dyer, C. B., .
Eichwald, E. von,

Emei'son, B. K.,
Emmons, E.,

Endlicher, *.
Elheridge, 11., jr.,
Evans,

Fahrenkohl, A.,
Fischer de Waldheini
Foerste, A. E., .

8,9, 10, 14, 15,
35, 36, 39. 40, 41,
63, 65, 66, 78, 79,
lUI, 103, 107, 108,
126, 127, 123, 129,
151, 152, 155, 156,
20.5, 204, 205, 211,
2(6. 249, 250, 253,
270, 271, 271, 279,
297, 298, 300, 301,
314, 317, 319, 320,

. 70, 107,

120, 145, 188, 208,

254, 261, 267,

245, 246,

. 80, 110, 152
245, 266, 269, 270

2, 3, .56, 138, 145
205, 245

16, 17. 1.8, 19,
43, 44, 45, 46,
80, 83, 84, 85,
11(1, 111, 112,
133. 138, 141,
158, 160, IJl,
212, 214, 227,
264, 2.')7. 2.59,
250, 281, 284,
303, 301, 306,
32), 333, 334,
120, 285, 304,
211, 213, 214,
268, 304, 314,
247, 249, 250,
2
116, 120,
138,
200,201,221,
297, 298, 321,
■ 3,
160, 196, 200,
257, 269, 281,

335,

Ford, S. W.

Freeh, F.,

Garnier, F. ,

Geinitz, H. B., .

Goldluss, A-,

Gould, A. A., .

Gratlolet, P.,

Gray, J. E.,

Guillier, A.,

Gurley, W.,

Hall, J., . . 2, 3

66, 67, 69, 73, 87, 91,

192, 194, 195, 190,

209,211,214,230,

264, 269, 272, 270,

300, 303, 304,

. 249, 253, 256, 303, 317,
. 188, 189, 193, 198, 201, 206,
22,8, 251, 291,
51, 50, 06, 67, 68, 69, 70, 71, 72. 75, 70, 77,

150, 214, 217, 201, 267, 304, 314,
. 303,321,

14, 18, .1:1, 36, 40, 44, 40, .56, 59,
120, 122, 138, 142, 145, 155, 187,
198, 199, 200, 201, 202, 2.')5, 200.
240, 245, 246, 249, 253, 254, 257.
277, 281, 284, 283, 290, 291, 295,
310, 312, 314, 319, 321, 322, 323,

20
48
87
113
142
192
233
261
285
313
335
322
216
322
252
145
136
272
2J3
337
304
201
295
104
336
256
303
321
209
296
78
62
266
319
333
123
65
122
63
145
61
188
208
261
268
328

356

INDEX.

Hancock, A.,
Haitt, C. F.,
Haupt,

Hayilen, F. V.,
Helmerspn, G. von,
Hcnick, C. L.,

Hicks, H.,.
UiiKle, G. J.,
Uisinger, W. von,
Holl, H. B., .
Huxley, T. H., .
Ives, J. C.,
Jaekel, O.,
James, J. F.,
James, U. P.,

JoubiQ, E-
Kayser, E.,

9S, 107,

. 4, 147,
120, 137, 1S8, 231,K2,

3, 6li,
3,9, 1-Jl,

120, 261, 264, 303, 304,
319,

133, 189, 209, 254,261,
323,

188,

200, 204, 276, 290,

. 6,

1,

. 3, 18, 19, 145, 188,

153, 211, 241, 242, 253, 259, 260,

Keycs, C. B.,

Keyseiling, A. von, ....

King, C.

King, W., . 2, 7, 10, 11, 13, 14, 18, 20, 21, t.

34, 35, 36, 38, 40, 41, 43, 44, 45, 46, 48, 51, 5,

;.63, 145, 147, 119, 156, 186, 200, 201, 204,

249, 251,;.'52, 267, 276, 279, 314, 317, 319,

Kloeden, K. F. von, ....

Koninck, L. de, . . 211, 2S3, 267, 276, 301,

314,317,319,321,323,
Kiotow, ......

Kutorga, S., . . 80, 82, 95, 101, 102. 103, 109,

113, 115, 116, 120, 128, 135,

5, 120, 121, 122,145,

33,34,36,38,201, 204,

86, 91, 94, 97, 93, 99,

145,

Lacaze- Duthiers,

Lamarck, J. 1'. B. A. de M. de,

Linck, ....

Liudstrfim, G.,

Linnarsson, J. G. O.

LiUDc, C,

Marcou, J., .... .

Marcy, O, .

Martin, W .

Matthen-, G. F., . 66, 5S, 69, 81, 91, 93, 99,

105, 107, 137, 183,
Maurer, F., .

McCliesney, J. H., . 120, 187, 188, 194, 196, 261,

McCoy, F., . . 65, 85, 129, l.M, 153, 187, 200,

211, 233, 245, 253, 261, 269, 276, 280, 284,

Meek, F.B., . 3,33,36,66,62,64,66,90,97,

127, 132, 1.35, 187, 188, 194, 196, 198, 201,

214, 215, 217, 245, 250, 253, 2,H, 261, 267,

281, 284, 290, 295, 303, 304,

Michaud, A. L. G., ....

MickwiU, A., .....

Miller, S. A., .

Mdller, V. von,
Mllller, O. F., .
Morris, J.,
Morse, E. S.,
Morton, L. G.,
MUnster, G. von,
Municr-Chalmas,

201, 205,

276, 281,
1, 147,

285, 286,
301,
304,

. L07,

30,31,
65, hi,
211, 245,
320, 328,
. 276,
302, 303,
325, 333,

110,111,
136, 158,

3, 8, 1.38, 145, 188, 194
:, 205, 208, 245, 272, 276

241, 245,
101, 107,
l.W, 204,
187, 208,

• .211,
101, 102,
231, 232,

262, 322,
201, 203,
290, 298,
314,
101, lOJ,
205, 208,
269, 272,
309, 322,

337,
196, 198,
281, 295,
i)5, 96,
122, 145,
110, 135,
8,

28,

148
254
294
322
320
304
328
6
201
303
90
186
266
291
8
245
295
149
290
302
323
317
61
33
62
248
339
303
306
331
310
112
160
16
321
321
274
108
213
322
284
321
103
233
269
350
304
303
321
120
211
276
328
321
339
201
323
102
IM
303

:6

321
3U
298

Murchison, R. I.,

. 66, 227,

328

Nettelrotli, H.,

3

146

189

193,198,201,206.

209

211,

251,

277, 285, 290, 304,

328

Neumajr, M., .

301,

324

Newberry, J. S.,

9, 2()4, 266, 303,

322

Nictiolson, H. A.,

3, 33, 36

120

138, 145, 188, 192,

201

2.54, 285, 304,

328

Norwood, J. G.,

303

312, 321, 328, 332,

333

CEhlert, I>, P., .

28,

153,

208,

209, 210, 233, 241,

243

250, 254, 261,

267

269,

272,

277

286, 287, 288, 289,
302, 310, 326, 333,

296
335

Oldham, R., .

29

Orbigny, A. d', .

120

128

136,

138

141, 158, 160, 186,

214

217,

2.33,

234, 237, 245, 303,

321

Owen, D. D.,

'

,69

187

192, 200, 208, 225,
261, 284, 303,

245
321

Owen,R.,.

. 2, 16,

186

Pander, C. H.,

80,

117,

118,

119,

141, 186, 192, 200,

221

233, 234, 235,

236

237,

238,

250,

284, 296, 296, 297,

298

Parkinson, J., .

321

Phillips, J.,

2,6

,15,

201,

211,

246, 253, 256, 257,
269, 276, 284,

261
303

Pilsbry, H. A., .

246

Poll, J. X., .

145,

147

Poticz, V. L. v.,

,

321

i'oulson, C. A.,

250

Pratten, U., ; .

303

312, 321, 328, 332,

333

Prout, U. A.,

321

Quenstedt, F. A.,

80,

109,

110, 200, 205, 211,
241, 245, 267,

219
301

Rafluesque, C. S., .

245

246

247, 248, 249, 250,

262

Ramsay, A. C, .

204

Rang, A. S., .

321

Uatbbuu, R.,

3, 120,188,304,

328

Reeve, L. A.,

,

121

Retzius, A. J., .

.

. 145,

150

Rieman, P., .

218

Uigaux, E.,

241

Ringueberg, E. N. S.,

3

120, 116, 189. 204,

205

Roemer, F.,

■ ■-,

187, 205, 276, 290,

302

Rogers, U. D.,

195, 201, 281, 284,

322

Rouault, M.,

36,

241

Salter, J. W.,

6,

36, 55, 56

,57,

58, 83, 84, 86, 107,

153

158, 187, 192,

196

201,

204,

241,

246, 269, 274, 284,

322

Sandberger, G. and F

,

253

Safford, J. M.,

188,199,200,241,

341

Schauroth, K. F.,

145,

150

Schiel,

321

Schlotheim, E. von.

145,

155,

158, 186, 200, 202,
213, 233, 253,

211
267

Schnur, S, .

241,

263, 257, 259, 284,

301

Schmidt, Fr.

86.

290

Schuchert, C,

25, 88,

112

.Schumacher,

,

121, 122,

123

Seebach, K. von.

101

Senienow, P., .

253

Shalcr, N. S.,

187,

189,

192

196, 198, 208, 233,
276, 281, 288,

246
295

Sharpe, 1).,

118. 138, 141, 248,

303

Shepard, G U.,

321

Siiumard, B. F.,

3,

120,

145,

187,803,319,321,

322

■Simpson, G. B.,

. 189, 209,

304

Sowerby, J.,

120,

121,

122,

150, 156, 168, 192,

203

:204, 211,

227

246,

253,

276,

384, 290, 317, 321,

328

INDEX.

357

145, 264,

187, 208, 264, 281, 322,

241,

So^verby, J. de C., .
Spencer, J. W.,
St. John, O ,
Stevens, .
Stobceus, K.,
Stoliczka, F.,
Swallow, G. C.,
Swinton, F. S., .
Tsehernyschew, Th ,
TraiitschoUi, H. vou,
Tryon, G. W.,
Uliich, E. O., .

Ure, D.,
Vanuxem, L.,

Veineuil, E. de,

219, 233, 23S:

297, 29S, 300
Verworn,

Volborth, A. von, .
Waagen, W , . . . 28, 29, 30, S4, 89, 90, 94, 95, 118,

154, 210, 214, 215, 216, 217, 239, 254, 256, 261, 262,

264, 265, 267, 268, 304, 306, 307, 308, 310, 313, 316,
319, 320, 324, 325, 326, 330, 331,

Waller,

Warth, H

Waloh, J. E. J.,

PAGE.
121, 276
. 146
314
303
145
29
328
218
243
214
246

. 24, 25, 27, 31, 53, 87, 88, 89, 112,

138, 148, 188, 194,

303,

2, 120, 186, 205, 211, 253, 257,
276,281, 284, 299. 303,

110, HI, 141, 151, 191, 200, 201, 204,
215, 253, 256, 264, 266, 269, 276, 280,
301, 303, 317, 319, 321, 323, 325, 328,

73, 82,

120
295
321
258
328
214
288
333
1.55

S3
147
263
317
332
145

30
321

W.nlcott, C. D.,

71, 72,75.78, 91,

105, 106, 107, HI

1S8, 189, 193, 194

246, 254,

Waldheim. G. F. de, .

Wenjukoff, P.,

WTiite, C. A., . 3, 90,98,
196, 198, 201, 206,

Whiteaves, J. F., .

Whitfleld, R. P ,

69, 120, 187, 188, 189,
233, 239, 240, 215,

Wi'lckens, C. F.,
Williams, H. S.,
Wiochell, A.,

Winchell, N. H ,
Woodward, S. P., .
Worthen, A. W.,

Wynne,
Yandell, L. P.,
Tonng, J.,
Zittel, K. A. von,
Zugmayer, H.,

3, 9, 56, 57, 63, 66, 67, 68, 69,
92, 97, 98, 99, 100, 101, 102, 103,
,113, 114, 116, 117,121, 137, 146,
, 198, 206, 211, 230, 231, 232, 241,
269, 278, 2S5, 290, 304, 314, 328,
191,214,215,264,266,

101,120,121, 145,146,187,188,

, 208, 209, 211, 245, 253, 264, 277,

285, 304, 314, 322,

3, 27, 40, 44, 45, 46,56,113,

244, 293,

. 3, 11, 36, 48, 57, 59, 61, 62,

195, 198, 206, 208, 209, 211, 218,

246, 253, 254, 269, 277, 281, 285,

310, 311,322,

276,

3, 62, 64, 120, 145, 152, 187,
208, 211, 253, 284, 304, 314, 322,
3, 59, 62, 145, 188, 194, 195, 206,

3, 36, 62, 64, 120, 121, 188, 253,
276, 2S1, 290, 303, 309, 322,

PAGE.

9, 70
104
155
243
332
275
259
192
281
323

lis

314
66
230
304
323
279
3
188
3-28
281
56
261
328
29
187
307

. 124, 272, 295,

II. Register op Genera.

(Names in italics are synonyms; figures in full-face type denote place of description.)

PAGE.

PAGE.

Acritis,

80,

82

Brachyprion,

220, 388, 2S9, 292

Acrotbele,

70, 98, 99, 100, 102

1U3, 108, 113,114,167,

168

Cadomella,

298

Acrothele ? .

101

Camarella,

234

Acrotrela,

. 63, 93, 95, 96,

99, 100, 101, 103, 104,

105

Camarella,

269

106, 103,

109, 113, 114, 166, 167,

168

Cardiuocrania,

30, 147, 1S4

Acrotreta,

95,

105

Cbonetella, .

307, 313

Ambocoelia,

92

Chonetes, .

191, 230, 280, 301, 303, 305, 306, 307

Amphiclina,

302

308, 309, 310, 311, 312, 313, 316, 320

Amphistrophia,

393

Chonetes,

314, 317

Ancistrocrania,

146

Chonetina,

. 307, 310

ATWmia,

. 145,211,

321

Choniopora,

145, 150

Anomites,

233, 276,

321

Chouostropliia,

307, 310, 311

Anoplia,

309

Chonotreta,

96, 104, 167, 168

Anoplotheca,

. 220,

302

Chonopectus,

. 307, 313

Arbusculites,

321

Choristites,

. 214,216, 264

Area,

321

Christiani.i,

398

Atrypa,

207,

293

Clavagella,

321, 333

Atrypa, .

187, 200,

269

Ciitambonites,

218, 219, 230, 231, 232, 333, 234

Aulonotreta, .

88,

337

2;36, 237, 239, 240, 243, 340

AulonotTeta,

SO

Conchitea,

276

Aulosteges, .

316, 319,

330

Conocephalites,

30

Aulosteges,

314

{Conradia,}

39

Avicula,

66

Crania,

1, 103,

122, 144, 145, 147, 149, 150, 151, 152

Barroisella,

1, 14, ea, M, 85, 103,

164

153, 154, 155, 166, 157, 158, 169, 170

Billingsella, .

.

339, 231,

232

Crania,

110, 314

Sittingsia,

75,

76

Crania [Pseudocrania) .

253

Bilobites,

. 304, 219, 223,

229

Craniella,

163, 170

358

INDEX.

Craniolites,

Craniops,

Craniscus,

Criopodernui, .

Criojfus,

Cycloneina,

Dalmanclla,

DamdsonelUi,

Davidsonia,

Daviesiclia,

Delthyris, .

Derbyu,

Derbyia, .

Dicellomus,

Dicalosiu,

liicranisuus, .

Dicraniscus,

Diijnomia,

liiuoboltis,

Dinobolus,

IJinoi-tliis,

Discina,

Discina, .

Uiscinisca,

{Ditcinocaris?,)

Disciiiolepis,

Discinopsis,

Douvillina,

Elkania, .

Enteletes,

Etlieiiiiyina,

Geinitzia,

Ulossina, .

Glolliiliu,

Gonainboiiites,

Gonfimbonites,

Gotlanditi,

Gryphites,

Hebei tcUa,

lleliner^enia,

Ileniipronites,

ffemipronites,

Bemithyria,

llctcrorthia, .

Hipparionyx,

ffysterolitlies,

Hyaterotitkui,

Iphiilea,

Iphldea (?,?),

Kayserella,

Keyseilicgia,

Klitambonites,

KoniiH-.kclbi,

Koninckina, .

Ivuturgina,

Lalvliiiiiiia,
Liffulops, .
Liiulstroiinclla,
Lingula, . 1, H,
27, •IIS, 3-.',

LinffuUi, .

■>. B, 8
48, 19,

r.\(;E.
. 145
159
146
U5
147
14S

155,

145,

ao5, 21S, 2iy, 2'jo, -Hi,

276, 30X,

2S

302

317

1S6, 187, 200, 201, 204

■-'58, 261, 202, 2ia, 265, 26j 347

• 261

60, (18, 7i, 73

. 204

270

. 269

164

48

176

44

229

169

155

169

142

141

168

2, 14, 15, 21, 163,

23, 28, .iO, 31, 34, 36, 39, 46, 47,

52, 53, 51, 55, SI, 84, 139, 142, 165,

36,

19.5, 2-23, 227,

. 180, 121, 121, 119, 150,

9J, 98, 107, 120, 122, 124, 129, 132,

laO, 133, 124, 125, 130, 131, 149,

29,90,110,
. 10.!, 105, 106, 107,

2,>6, 388

51, 32, 54, 69, 75, 76, 77, 78, 165

. 314, 215, 216, 217, 226, 229

336

104
10
164
237
233
33
o21
229
119
250
261
. 269
. 308, 223, 229
357, 2,')8, 265
. 186,211,
186,
90, 97, 160, 167,

■ 2, 1">,

U, 15, 03, 103,
219, 2i6,

1 98, 222,

117,118,

336, 338, 239,

.233, 239, 245, 253, 254,

117,118,119,

. 233.235,

. 298,

301,

90, (II, 92, 93, 94, 95, 96, 97, 114,

166, KiS,

. 28, 30, 35, 46, 47, 48, 52, .53,

130, 134,

10, II, 14, 15, 10, 18, 21, 22, 23, 24,

50, 51, 52, 54, 56, 57, 58, ,59, 61, 62,

64, 65, 109, 161, 162, 163, 164,

. 2, 18, 36, .55, 56, 59, 62, 66,

213

213

163

90

359

141

236

302

302

140

183

89

19

140

25

63

166

Lingula ?

Lin(jula[Glottidm),
Lingularius. .
Lingulasnia,

Lingulella,

Lingulellii [ Dignomiii '? ) ,
lanj^iilupis,
Lingtilepis,
Lingulops,

PAGE.

66, 62, 86

. 62

34, 25, 27, 30, 32, 40, 47, 48 49,

51, .52,63, 78, 81,

0, 7, 8, 19, 52, 55, 50, 57, 58, 59,

62,61, 69, 92, 162,

6,59,01,81,

Lcptasna,

Leptceiia,

Lepfccnalosia,

L(!l)ta;nisca,

Leptainulopsis,

Leptagonia, .

Leptella. .

Leptobolus, .

LuplocffiUa,

Leptostrophia,

Lima,

Liniiars..^onia,

M.''vginirera,

Meekella,

Me.sotreta,

Mickwitzia, .

Mimulus, .

Monoboliua, .

MonomercUa,

Mystropliora, .

Mytilus,

.Neobolus,

Numulus,

Obcilella,

77, 78, 81
Obotella,
OboletlaJ, .
Obolcllina,
Obolus,

50
!03

61
105

56
163

60

48
165
286
299
317

8, 18, 19, 20, 21, 22, 23, 24, 25, 30, 32,

47, 48, 49, 51, ,52, 51, 55, 1.56, 163,

192, 220, 236, 2.50, 276, 279, 280, 28J,

293, 290,

47, 187, 196, 225, 253, 261, 281, 284. 314,

321, 328

314

301
394
280
29S
107
220
288
321

;os

332

2(«

HI

86

274

84

39

176

241

321

165

145

76

3.39

107

83

44

139

339

119

86

36

169

30

141

150

158

145

133

169

236

192

344

193, 194, 197, 201

203, 210, 215, 216, 217, 218, 219, 2i0, 221 , 224, 225, 227

228, 229, 230, 231, 232, 230, 242, 243, 252, 257, 298,

80, 211, 230, 231, 233, 211, 244, 243, 253,

201, 261, 207, 209, 276, 281, 284, 314,

. 279, 300,

276,

393, 294,

73, 74, 75, 79, 165,

68, 69, 70, 100, 107, 109, 113, 167,

330, 331,

219, 259, 262, 263, 364, 265, 266,

105, 109,

80.

270, 272, 273,

SO, 83,

22, 23, 28, 29, 30, 31, 34, 35, 36, 37,

40, 41, 43,46,60, 53, 101,

1, 29, 30, 80, 84, 89,118,

.52, 57, 5S, 01, 64, 66, OS, 69, 70, 72, 73, 75,

81, 83, 85, 88, 89, 91, lOS, 140, 164, 163, 167.

. 50, 75, 90,

51, .52, 1)6,

Obolus,

Obol-as?,

Obolus I Trimerclla]

CEhlcrlclla, .

OleiULs (?),

Orbicella,

Orbicuxa, .

Orbicularius, ,
Orbiculoiclea,

135, 136, 13:
OrLhainbonites,
Orthambonites,
OrLhiiUuTii,
Orthis,

Orthis, .

,56, ,57

,36,

?2, 77, 80, SI, 82, 83, 84, 86, 108,

140, 165, 183, 337,

36, 44, 60, 83, 90, 98, 117, 118,

83,

130, 133, 141, KiS,

118, 119, 138,

, 00, 118, 120, 121, 138. 143, 145,

165,

130, 121, 1-24, 125, 128, 129, 132,
138, 140, 144, 150, 158, luO, 166, 168,

186,

92, 185, 186, 191, 192

301

259
319

INDEX.

359

r

IRE.

r.

VGE.

Ortliis (Schizophoria)

.

216

Schizotrela, . 116,130,125,128,131,135,136,

UO

Orthisiiia, /

98, 219, 230, 232, 23«, 237,

240

144, 158,

168

Orihisina, .

230,233,253, 261, 2G4,

267

Schniidtia, . .73, SO, 83, 165, 167,

337

Ortliostropliia,

. 199,223,

229

Siplloiiotrela, 79, 94, 99, 108, 109, 110, 111, 112, 114, 115,

119

Oithothetes,

. 21 S,

219, 220, 219, 353, 255, 256,

257

140, 160, 167,

168

3.58,261,262,268,

295

Skenidium, . . , . 241,

247

Orilwthrix, .

314

Spii'ifer,

201

Orthotichia,

313 226,

229

Spiri/er. . . 186,187,200,201,204,214,261,

269

OstracUes,

115

Spirt/era, .... .201,211,2.53,

272

Palaomaia ?,

133

Spoiiilyloholus, . . . . ;1, 80, 85, 108,

164

PalKOcrania, .

. . isa.

159

Spondylus, .......

314

Patella, .

115, 165,

158

Stenoschisma, ......

234

PateUUes,

155,

158

Stenotheca, s. g-. Parmorphorella, . . . .

137

Paterula, .

. ■ .78, 165, 1C6,

163

Streptis, ..... 270, 271, 273,

374

I'entainerLis, .

234

Streptis,

272

Pharelra, .

.1

Streptorhynrhus, . . 219, 257, 260, 2G2, 2C5, 367,

268

Pholiilops,

■ 1.

151, 152, 155, 156, 157, 158,

170

Streptorhynchus, . . 47,245,2.53,254,359,261,

264

rholi'lostropliia,

387

.Sti-icklau'liiiia, ......

220

Pinna,

321

Strophalo.sia, . . 314, 315, 316, 319, 320, 330,

335

Pliesioinys,
Platystrophia,

. 196, 2-22,

229

Sirophalosiii, ...... 319,

328

300, 203, 22:;,

229

Strophc'odoiua, . . 220, 2.58, 282, 38*. 286, 287, 288,

292, 307,

289
311

Plectambonites,

220, 236, 250, 293, 29i, 395,

296

297, 298, 299, 300, 302, 305.

306

Strophodonin. ... 47, 136, 185, 281,
Strophnnluna, . 197, 220. 345, 240, 218, 250, 251,

28.5
2.52

PUctamhonites, .

. 276,

284

2.55,262,279,282,286,291,

311

Plectorlhis, .

. 194,221,

22!)

Strophomemi, . 47, 187, 196, 2.53, 276, 277, 2S1,

284

Pleurotoiiiaria, .

.

lis

285, 286, 314, 321,

328

Plicalula,

264

atrophomenes, .... 245, 246, 348,

252

Polytccohia,

. 238,

339

Strophonella, . . 136,191,220,279,282,289,

390

Porambonites,

217,

219

291, 292,296,

311

Pornmbonites,

. 186,

200

Syntridasma, ..... 214,

216

Proboscidella,

333

Terobi-atahi, ......

16

Producta,

269, 276,

.121

Terebratula, . 110, 1,S6, 200, 204, 211, 214, 269, 321,

324

Proiluctclla, .

301, 315, 318, 325, 338, 329,

332

Terebratulina, .......

16

Productella,

.

314

Terebratulites, .... 200,211,25:!,

267

Pioiiuotus,

185

220,263, 280, 297,301, 307,

316

Thecidium 16,

28

318, 319, 3iO,

331, 323

325, 330, 331, 332, 334, 3:i5,

336

Tliec.ospira, .......

302

Productus,

186, 276, 314, 317, 3-28,

333

Tomasina, ......

65

Pronitcs,

. 219,336,

237

Trematis, . i~i, .89, 92, 118, 131, 132, 138, 140, 141, 168,

169

Pronites, .

233

Trematis • 36, 87,

142

Protonia,

321

Trematis 1, ...... .

90

Protorthis,

219,331,232,

238

Trematis {Schizocrania] , . . . . .

142

Psemlocrauia,

. 151, 152,

159

Trematospira '^ , ......

1.87

Pyxis,

321

Tridacna, .......

321

Rafincsquina,

381, 282, 286, 289,

298

Trimerclla, 1, 21, 2,5, 28, 29,30, 31, 33, 35, 37,39, 40, 42, 43

44

Rbinobolus, . -2

;, 31, 31, ;

,2, 43, 43, 44, 45, 46, .50, 52,

53

46, 47, 48, 49, .50, 51, .52, .53, 55, 113, 156, 163, 164,

165

Rhipidomella,

. 208

210, 212, 219, 220, 224, 229,

254

Trimerella, .......

44

RhipidomelUc,

214

Trimerellal, . ......

44

Rhipidomys,

. 208,

2in

Tiiplecia, ... 369,270,271,273,

274

Rhynobolus,

44,

46

Triplesia

269

Richtholenia,

154

Tiopidoleptus 207,

220

Rocmerella, .

130,

137

Tubil'e.x, .......

8

Scenidium,

. 218, 341, 242. 243,

259

Unguta, ........

80

Sobizambon, . 98,

108, 100,

111, 113, 114, 116,167,168,

169

Ungulites .......

SO

Schizobolus,

79, 87, 89, 140, 165, 166,

168

Volboi-thia, . 93, 95, 96, 98, 102, 166, 167,

16S

Schizocrauia,

43, 89,

131, 132,140, 143,144,168,

169

Waagenia, .......

239

SchizophoUs,

29, 93, 94, 95, 96, 166,

168

Waagenella, .......

239

Schizophoria,

311

212, 213, 214, 219, 226, 229,

343

Waldheimia, .......

331

360

INDEX.

III. Register of Species.

(Jfiines in italics arc sjruonym:-: figures in fdli.-face typo after new species denote tlie place of description.)

PAGE.

PAGE.

Acrili

.s antiquissima, von Eicliwald, .

82

Chonct

trs niuci'onala. Hall,

306

Acrothele coriacea, Linnarsson,

.99,

100

C.

muricata. Hall,

316

A.I

dichotoma, Walcoit, .

100.

103

C.

Nova-scotica, Hall,

308

A.

granulata, Linnarsson, .

100

C.

papilionacea, Phillips,

307

A.

Matthewi, Hartt,

99, 100,

101

C.

polita, McCoy,

306

A.

subsidua, White, .

100,

101

C.

tenuistriata, Hall,

308

Acrot

reta attenuata, Mcel;,

103

c.

undulata. Hall, . . . .

308

A.

Babel, Barratide, .

105

c.

Vcrneuiliana, Norwood and Pratten.

310

A.

Baileyi, Matthew,

911, lO'i.

103

Chone

ina Artiensi.s, Krotow,

310

A ?

costata, Davidson,

lot

Chonostrophia Helderbergia, sp. nov.

. 311,

363

A.

disp.aririiffata, Kutorga,

lO:, 103,

101

Clitam

>ouiles adscendens. Pander,

237,

238

A.

gemma, Billings,

. 10-2, 103,

lOli

Concliites rhomboidalis, Wilckens,

279

A.I

Gulielmi, Matthew, .

103,

105

Conchyliolithits anomites resupinata, Martin,

211

A

Xicholsoni, Davidson,

103

Conotieta llusti, Walcott,

104

A.

pyxidicula. White,

103

Crania agaricina, sp. no\- ,

180

A.

recurva, Kutorga .

!).i,

102

C.

anoniala. Mailer,

117

A.

socialis, von Seebach, .

113

C.

antiquissima, von Eichwald, .

151

A.

subconica. Meek, .

. 101, 103,

lot

C.

Br:;ttensburgensis, Retzius, .

150

A.I

subsidua. White,

100

C. ?

Columbiana, Walcott,

150

Anomia bitoba, I.inne,

204

C.

craniolaris, Linne,

146

A.

craniolaris, Linne,

150

c.

craniolaris, McCoy,

85

Anomites productus, Martin,

325

C.

lavincola, sp. nov..

181

A

semireiiculatus, Martin,

325

C.

granosa, sp. nov

ISO

Atrypa7 apiculata, SiiUer,

270.

c.

Ignabergensis, Retzius

147

A.

cuspidata. Hall,

270

c.

multipunctata. Miller,

148

A.

extans, Emmons, .

270

C.

parallela, Ulrich,

143

A.I

incerta, Davidson,

270

c.

Parisiensis, Defrance,

!46

A.

nucleus, Hall,

270

c.

percarinata, Ulrich, .

J

148

A

(Triplecia) apiculata, Salter,

271

c.

pulchella, sp. nov..

180

A.

(T.) incerta, Davidson,

271

c.

radicans, Winchell. .

316

Aulonotreta polita, Kutorga,

SO

82

c.

radiosa, Gould,

121

A.

sculpta, Kutorga, .

S2

c.

pcabiosa. Hall. ....

148

Aulosleges Ualhousii, Davidson,

320

C.

Schaurothi, Geinitz,

151

A.

guadalnpensis, Shumard,

320

c.

Sedgwicici, l.e^is.

85

. 87

A

Medlicottiauus, Waagen,

320

c.

setifera, Hall,

151

A.

spondyliformis. White and St. John

316

320

c.

setigera, Hall, ....

KO,

151

A.

variabilis, von llelmersen.

319

320

c.

socialis, Ulrich,

U8

A.

Wangenheimi, de Venteuil,

319

c.

striata, Schumacher, .

121

Aviculal desquamata.llM,

67

c.

Trentonensis, Hall,

150

Barroisella subspatulata, Meek and Worth

'n, 1>, 63

164

C.

tripartita, Miinster,

H6

Bruchy prion I^cda, Billings,

2SS

c.

iCraniella) Hamiltoniic, Hall, .

148

B.

genicnlatum, Shaler, .

288

c.

[ Psendocrania) anomala, Winchell.

152

B.

venlricosum, Shaler,

288

C. (P.)

divaricatu. McCoy,

148, 149,

158

Caniarella calcilera, Billings, .

. 270

271

Cranit

11a HamiUoni.'o, Hall, .

153

Card

nocrarna indica, Waagen, .

154

C

Meduanensis, (Ehlert,

1.53

Christiania sul)quadrata, sj). nor., .

351

C.

Ulrichi, sp. nov,,

153,

181

Chonetella nasula, Waagen.,

313

Davidsonia Bouchardiana, de Koninch,

302

Chonetes Autiopia, Billings, .

308

D.

Vcrncuili, Bouchard, .

302

C.

Canadensis, Billings,

308

Davidsonella linguloides , Waagen,

89

C.

complanata, Ilall,

311

D.

(=: Lakhminal linguloides, Waagen,

28

C.

cornuta, Hall,

308

Derby

a afflnis, sp. nov..

349

350

C.

coronal a, Conrad,

312

D.

Bennetli, sp. nov..

. 263,

348

C.

Dawsoni, Billings,

311

D

biloba, sp. nov..

350

C.

Fischeri, Norwood and I'nitten, .

312

D.

Broadhcadi, sp. nov..

263, .346

347

C.

glabra, Qeinitz.

306

D.

Correana, Derby, .

263

C.

Icevis, Keyes, . . .

306

D. ?

costatula, sp. nov., .

346

C.

lepida. Hall,

306

D.

crassa. Meek and Hayden,

263

C.

liueata, Vanuxem.

306

D.

grandis, Wangen,

262

C.

niesoloba, Norwood and Pratteti,

310

D.

Keokuk, Hall,

262

C.

minima, Sowerby,

291

D.

regnlaris, Waagen,

262

INDEX.

361

Derbya robusta, HaU,

D. ruginosa, sp. nov.,

Dinobola3 Bohemicus, Barrande,

D. Biimonti, RouauU,

D. Canailensis, Bitlinga,

D Conradi, Ball, . M, 39, 40,

U. Hicksi. Daxidson, .

L>, magnificus, BiUings, .

I). parvus, Whitfield,

I>. Schmidti, Davidson and King,

D. transversus, Salter,

D. WoocI«ai<li, Salter, .

Discina acadica, llartt,

D. ampla. Hall, ....

D 1 Baldetchensis, Uavidson,

/>. Bohemica, Barrande,

D Caer/ttiensis, Hicks,

D. Clara, Spencer,

D Conradi, Hall,

D discu3. Hall,

£>. Doria, Hall,

X)- grandis, Vanuxem,

D. humilis. Hall,

Z). Nerzeri, sp. nov.,

D. intermedia, Barrande,

D. inutilis. Hall, .

D. Uimellosa, Brodarip,

D. Lodensis, Hall,

D. M(eotis, Barrande,

D. ManUattan&isis, Meek and Worthen,

X>. marginalis, Whitfield,

D. media. Hall, ....

D. minuta. Hall,

i>. Morrisi, Davidson,

D. Newberryi, Hall, .

D. nitida, Phillips,

D. ostraoides, Lamarck,

D. pUeolus, Hicks,

D. pleurites. Meek,

D. EandaUi, Hall,

D. reversa, Barrande,

D. rugata, Barrande,

D. secedens, Barrande

D. striata, Schumacher,

D. striata, Sowerby,

D. tarda, Barrande,

D. ienuiiamellata. Hall,

D. truncata Hall,

D. (CEhlertella) pleurites. .
Discinisca lamellosa, Broderip,
Discinolepis granulata, Waagen,
Discinopsis Gulielmi, Matthew,
Boavillina Dutertrii, Murchison,
Elkania desiderata, BiUings,
Enteletes ferrugineus, Waagen, .

E. hemiplicatus, Hall, .

E. l,:imaTcki, HscTier de Waldheim,

E. pentameroides, Waagen,

Glottidia Audcbardi, Broderip, .
G. ralmeri, Datt,

Gouambonites lata, Pander,
Hemipronites alta. Pander, .
B. Americana, Whitfleld,

H. apicalis, \Vliitfleld, .

i-2, 4:i, 17.1,

39,
39,
39,

39,

1-25, l-'7.

I'AOE.

■262

. 346

39
:i9
170
39
39
41)
4U
40
40
137
130

. 127

137

. 125

125, 130

125, 132

125

1-25, 136

1-25

. 127, 131

135

. 137

1-22, 1-23

. 125

127

. 125

125, 127

. 1-25, 133

1-25, 131

. 1-29

1-25, 130

125,1-26, 131

121, 122

. 137

125, 131. 132

. 1-25

133, 135

. 135

101

l-2'2, 123, 125

122

. 135

125

87

140

131, 133, 13G

90

. 106

2S9

. 77

216

216, 217, 226

214, 215, 226

. 216

8

14, 63

237

238

■239

. 239, 240

Hemipronites nutans, Jamos,

H. splja?rica. Pander,

H. tumida. Pander, .

Hipparionyx consimilaris, Vanuxem,

H. consimilis, Vanuxem

H. pi-oxinius. Vanuxem,

H. similaris, \'anuxeni

Iphidea bella, Billings,

1. ornalella, Limiarsson,

I. (??) sculplilis. Meek,

Kutorgina cingulata, Billings, . 67,

K. cingulata var. pusilla, Linnarsson,

K Labradorica, Billings,

K. Latonrensis, Matthew,

K. minutissima, iTa/i and Whitfleld,

K. pannula, White,

K. Prospectensis. Walcott,

K. (?) pterineoides, Matthew,

K. sculplilis. Meek,

K. Whitfleldi, Walcott, .

Lakhmina linguloides, Waagen,

Leptcena (Enigma, de Verneuil,

L. altemata, Conrad,

L. alternistriata. HaU, .

L. analoga, Phillips,

L. aseUa, de Verneuil,

L. caudata, Schnur, .

L. concaia. Hall,

L. conrexa. Pander, .

L decipiens, Billings,

L. deltoidea, Conrad,

L. demissa, Conrad,

Z. depressot Sowerby,

L. eugiypha, Dalman,

L. Dutertrii, Murchison,

L. /o^cirtia. Hall, .

L. filitexta. Hall,

■ L. incrassata. Hall (Safford),

L. liasina, Bouchard,

; Z. Llandeiloensis, Davidson,

! L. Moorei, Davidson.

L multirugata, McCoy,

L. nodulosa, Phillips,

L ? nucleata. Hall,

L obUmga, de Verneuil,

L. obscura. Hall,

L. plicotis, McCoy,

L. planumbona. Hall,

L. rhomboidalis, Wilckens, 250, 279, 280,

L. rugosa, Hisinger,

L. semiovalis, McCoy,

L. sordida, Billings,

L. subquadrata. Hall,

Z. tenuicincta, McCoy, .

L. transversalis, Dalman,

L. unicostata. Meek and Worthen,

L. WaUoni, Davidson,

Leptaenisca adnascens, sp. nov.,

L concava. Hall,

L. tangens, sp. nov.,

Leptienulopsis simplex, Haupt,

Leptobolus insignis. Ball,

L. lepis, HaU,

L. ocoidens, HaU,

257, 258,

97,

97,

94,

!12, 93, 94,

9-2,

93, 94, 95,

91.

92,94,

9-2,

92,
92,

248, 280, -282,

PAOF.

•251, 345

. 238

238

. -258

258

259

•258

98

-282,

•294,

2S2.

250,
279,

97

95

94

94

-233

97

95

94

»4

94

94

-29

300

-2S3

282

279

288

-287

300

297

•298

2S3

286

279

296

288

282

-251

-282

29S

294

-29S

■279

308, 309
300
283
279
251
296
279
279
298
300
300
299
. 282
283

301, 352
301

-250,

186, 287

293,
299,

279, 296,

301,

73,
73, 74,

353

•294
74
75
73

362

INDEX.

PAGE.

PAGE.

Lindstrcemella aspidiuni, si>. hot.,

l:«,

178

Lingula Wavcrliensis, Herrick, .

9

Lingi

la acuminata, Conrad,

5

L.

VVhitii, Walcott,

9, 11, 12,

48

L.

aequalis, .ffiiH,

9

I..

Winona, Hall,

6

L.

oiMfia

13,

14

L.

zebra, Barrande,

18

L.

alveata, Hall,

14,

15

h.

(Glottidia) Audebardi, Broderip,

. 8,

162

I,.

anijila, Oicen, ....

6

Lins

ulasma Scliucherti, Ulrich,

24,

27

L.

aualina, Lamarck, 4, 5, 1!, 7, .•<, 10, il

, 15, 17, 21,

22

Ling

ulella ca;Iata, Hall, .

57, 58,

69

3-2,4

9, 51, i)5, 57,

60

L

Cincinnatiensis, Hall ami Wliitlielil

B9

L.

attenuata, Sowerby,

5,8,

15

L.

Davisi, McCoy,

56,

57

L.

Canadensis, Billings,

21,

27

L.

Uawsoni, Matthew, .

58

(..

ccntrilineata, Ball,

15

L.

Ella, HallA\M\ Whitfield,

87,

58

L.

conipta. sp. nov.

171

L.

ferruginea, Salter,

58

L.

Covingtonen.si.'i, Hall and Whitfield,

S

L.

Granvillensis, Walcott, .

53

L.

Criei, David.-ion,

65

L.

lowensis, Owen,

8, 14,

59

I,.

cramona, Phillips,

5,

15

L.

lepis, Salter,

58

I,.

cuneata, Conrad,

(!, 12,

15

Ling

ulepis antiqua. Halt,

61

L.

Dapline, Billings,

6

L.

cuneata, Whitfield,

61

L.

Davidsoni, Barrandt,

61

L.

Ella, Hall and Whitlield, .

61

L.

Datisi, McCoy,

57

L.

Majra, Hall and Whitfield,

61

L.

deusa, Hall, ....

9, W,

171

L.

miniina, Whitfield,

62

Delia, Hall,

15

L. ?

nnnntA, Hall luiiX Whitfield,

61

["

distincta. Barrande, .

18

L.

Morsii, N. H. Winchell,

62

r..

Elderi, Whitfield,

'.1, 11, 12,

4S

L.

perattenuala, Whitfield,

61

L.

epimia, Barrande,

IS

L.

pinnilbrmis, Owen,

60,

61

L.

Feislmanfeli, Uarrande,

68

Ling

ulops Granti, sp. nov. 19, 20,

21,

23, .32, 50,

173

I..

flabellula, yp nov..

G, 1.1,

172

L.

Xorwoodi, James, . 20,

21,

23, 32, 50,

173

L.

granulata, Phillips,

18,

27

L.

VilM&eMi, Hall, . 18,19,20,21,

23,

26, 32, 50,

173

L.

Hawkii, Ilouanlt,

0,

15

Linnarssonia ijretiosa, Billings,

109

T,.

insons, Barrande.

61

L.

misera, Billings, .

107, lOS,

109

L.

lowensis, Owen,

S

L.

sagittalis, Salter,

. 103,

109

L.

laraellata. Hall,

10, 1.', II), 18,

48

L.

Tacouica, Walcott,

106, 107, 108,

109

L.

Le;ena, Hall. ....

6

L.

transversa, Hartt,

107, 108,

109

I-.?

Lebeuei'i, liouault, . 7,

1), 11, i;:i, 65,

164

Mar

a^inirera ornata, Waagen,

331

L.

Lewisi, Sowerbg,

10

M.

typica, Waagen,

330,

331

I..

linguata, sp. nov..

173

Wickwitzia monililera, Linnarsson,

86

i.

Matthewi, Ilartt,

100

Mici

odon (Cypricardella) bellistriata, Conrad

148

L.

Melie, Hall,

10,11,

12

Mimulns contrarius, Barrande, .

373

L.

niembranacea, A. Winchell,

U4

M.

Waldronensis, Miller and Dyer, .

. 273,

274

L.

Mosia, Hall,

6

Monomerella Egani, sp. nov..

42,

175

Z,.

Korwoodi, Jaine.s,

8,

19

M.

Greenii, sp. nov . . 4-

',*■

),52, 174,

175

L.

palilbrmis, Hall, .

59,

64

M.

Kingi, sp. nov.

42,

174

I..

paracletus, sp. nov. .

10, 12,

173

M.

Lindstruimi, Davidson and King, .

41

I,.

perovala. Hall,

6

M.

orbicularis, Billings,

41

I,

petalon. Hicks,

6

M.

Ortoni, sp. nov.

42, 43,

175

L.

pinniformis, Owen,

59

M.

ovata, Whiteaves,

42,

54

L.I

polita. Hall, ....

67,

72

M.

prisca, Billings,

41, 42,

43

L.

prima IConrad), Hall,

69

M.

Walmstedti, Davidson and King,

41

I..

Procteri, Ulrich,

10, 12,

15

Neobolus Warthi, Wiiagen,

84

L.

jdumbea, Salter,

S3

N.

Wynnii, Waagen,

84

L.

punctata. Hall, . . 10,

11,12, 15,17,

48

Niimulus Brattemburgemis, IStobocus,

150

I..

pygmiea. Sailer,

li

Obo

clla atlantica, Walcott,

69

L.

ptjramidata, .Stimpson,

8

0.1

ambigua, Walcott,

69,

78

J..

quadrata, Hall,

14

0.

Belli, Davidson,

68

L.

lioinilVnini.-, Hall,

ti.

8

0.

ccelata. Hall,

69

L.

Rouauiti, Salter, .

C

o.

chroniatica, Billings, 60, 67, 68, 69,

70

72, 73, 75,

76

L.

scotica, Davidson,

. 6,9,

15

78,

91

L.

scutella, sp. nov..

171

0.

cingulata, Billings,

69,

91

L.

spatliata, Hall,

18

o.

Circe, Billings,

6S,

69

L.

spatiosa. Hall,

0

o.

crassa. Hall, 67, 68, 09,

70

71,72,75,

78

L.

squamosa, Holl,

6

0.

desiderata, IJillings, .

57, 69,

75

i.

subspatulata. Meek and Worthen,

63

0.

desquamata. Hall,

68

L.

tainiola, sp. nov.,

18,

173

o. ?

discoidca. Hall and Whitfield,

69

L.

tenuigrauulata, McCoy,

18,

27

0.

gemma, Billings,

68, 69, 70,

71

L.

Vanhoinii, Miller,

.

8

o ?

Ida, Billings

69

INDEX.

363

Obolclla raaculala, Hicks, .

O. misera, Billings,

O. nana, Meek and Hay den,

O. nilida, Ford,

O. Phillipsi, HoU,

O. poUla, Hall,

O. pretiosa, Billin^d,

O. Sabrinie, Callaway,

O. sagiltalis, Salter,

O. tratistersa. Havtt,

Obolus advena, Barrande,

O. anti(iui.ssimus, ron Eichwald,

O. AiK)llinis, von Eicktcald,

O. Appolinus, Owen,

O. ? Bohemicus, Harrandc,

0. 1 complexus, Barrande,

O. ingricus, von Eichwald,

O. Labradoi'icus , Billings,

O. pulcher, Matthew,

O. Quenstedti, Mickwitz,

O. siluricus, von Eichwald,

OEhlertella pleurites, Meek,

Orbicula antiquissima, von Eichwal

O. Buchi, de Verneuil, .

O. ccelala. Hall,

0. crassa, Hall,

0. deformaia. Hall, .

O. Morrisi, Davidson,

O. norregica, Sowerby,

O. norvegica, Lamarck,

O. punctata, Sowerby,

0. rerersa, de Verneuil,

0. ? squamifortnis. Hall,

O. terminalis, Emmons,

Ofbiculoidea, sp. ? Meek,

0. conica, Dwigtit,

O. Davidsoni, d'Orbigny,

O. Forhesi, Davidson,

O. gramlis, Vanuxem,

O. Herzeri, sp. nov.

O. Morrisi, Davidson,

O. Xewbenyi, Hall,

U. nitida, Phillips,

O. numulus, sp- nov.

O. Kandalli, Hall,

O. tenuilamellaia. Hall,

O. (Rosmerella) grandis, Vanuxem

O (Schizotrela) ovalis, sp. nov.

Orthambonites transversa, Pander,

Orthis acutUoba, Kingueberg,

O. acutilirata, Conrad,

O. sequivalvis. Hall,

O. alternata,

O. alsa, Hall,

O. ? apicalis, Billings,

O. arachnoidea, Pliillips,

O. arcuaria, sp. nov.,

0. Armanda, Billings,

O. assimilis. Hall,

U. Aurelia, Billings,

O. basalis, Dalman. .

O. Battis, Billings,

O. Baylii, Uouault,

O. bellarugosa. Hall,

uu,

6!*,

09,
G9,

116, I
1 ■-'.'•>, I

70, 72, 73,

68,

6S, 107,

70,

R8,

SO, 82,

81,

114,

8, 119,

151,

9, 130,

:«, 129,
129, l.!5,

l.«,

1^7,

217,

1, 192

109

69

7"

70

94

83

70

103

108

107

69

82

339

72

101

73

82

94

183

339

82

1C9

140

152

69

72

150

160

121

122

140

118

159

140

127

135

160

IbO

133

178

16U

130

13«

178

133

135

178

179

2.'i7

205

223

221

203

225

240

256

221

217

224

221

207

222

213

222

210,

Orthis bellula, James, ....

O. bilbrala, von Schlotheim, . . I'M,

O. Billingsi, llarti, ....

O. Billingsi, SalVonl, . . . . .

O. biloba, Xiime, 190, 304, 20.'>,

O. borealiii. Hillings, . . . . .

O. Boucliartli, Davidson, ....

O. Bui-lingtonensis, Hall, . . . .

O. callaetis, Dabnan, 191, 193, I!)'',

O, calligramma, Dalman, 190, 191, 192, 193, 194,

231,238,

O. calligramma, *ar. Davidsoni, de Vernetdl,

0 culligriimmn,\iu-.flabeUites,Foevstc, .

O calligramma, \ar. orlhumbonites, Billings,

O. carinala, Hull, ....

O. circularis, .....

O. circulus. Hall,

O. Clarkeusis, Swallmv, ....

O. Cleobis, Hall, ....

O. Clylie, Hall 202,

O. concinna. Hall, ....

O. corallina, Waagen, ....

0. CoHnna, Billings,

O. costalis. Hall, .

O. crassa. Meek,

O. crenistria, Phillips,

O. crispata, Emmons,

O. CumberUindia, Hall, .

O. cuneata, Oiven,

O. cyclas. Hall,

O. cylindrica, ...

O. Dalyana, Miller,

O. Davidsoni, de Verneuil,

O. Daytonensia, Foerste,

O. deflecta, Conrad,

0 deformis. Hall,

O. demissa, ....

O. Derbyi, Waageri,

O Deshayesi, ...

O. dichotoma, H(dl,

O. discus. Hall,

O. disparilis, Conrad,

O. dubia. Hall,

O. electra, Billings,

O. elegans, Bouchard,

O. elegantula, Dalman, 191, 192, 207

O. elegantula, var. |)a)-\a,

O. Ella, Hall,

O. eraacerata. Hall, .

O. eniinens. Hall,

O. Furekensis, Walcott,

O. Euryone, Billings,

O. Evadne, Billings,

O. excavata, Geinitz,

0. eximia, dc \'enieuil,

0. cxpansa, Sowei'by,

O. extensa, Pander, .

O. tasciata. Hall, .

O. I'austa, Foerste,

O. tissicosta. Hall,

O. aaiieUites,, Hall, .

O. flabellulum, Hall,

O. flabellulum, Sowerby,

0. gemmicula, Billings, .

r.VGE.

224

200, 223

232

. 219

223

. 222

217

. 225

196, 228

195, 219

212, 241
19J, 227

228
. 221

213, 226
. 259

224
225
2-25
223
2-21
210
217

221, 227, 228
223

. 248
224

. 225

225
262
225
228

21,

191,

222

255

192

. 214

243

. 221

210, 225

, 221, 228

210, 225

. 233

219

,224, 341

224

. 221

207, 224

210, 225

2.32

221, 228

223

. 315

266

. 283

219

200, 222

222

221

228

227

227

244

194,

364

INDEX.

!•

iGE.

Orthis

gibbosa, Billings,

224

Orthis

0.

Halli, Safford.

. '200,

223

0.

0.

hemipronitcs, \on Uuch,

238

0

0

bippiirionyx, Schnur,

25S

0

0.

Hilipoljte, Billings,

. 217,221,

228

0.

0 V

Holstoni, Safford,

, '218,

340

0.

O,

bybiidii, Sowerby,

. 210, 224,

342

0.

0.

ittonea, Hall,

225

0.

0

impei'ator, Billings,

222

0.

0

iniprcssa, Hall,

■212, 214,

226

0

o

jncisiva, Waagen,

210

0.

o

infera, Cuhin,

224

0.

0

insculpta, Hall,

222

0

0

insignis. Hall, .

241

0

0.

insularns.

270

0

o.

Iowensi.s, Hall,

. 212,

226

o

n_

Iphigcnia, Billings,

222

0.

O

Jamesi, Hall,

194, 193,

221

0.

0.

Kankakensis, McChesney,

221

0.

0

Kaskaskiensie, McChesney.

350

0.

0

Keokuk, Hall,

262

0.

0

laticosta. Meek,

223

0.

0.

Laurentina, Billings,

. 194,231,

238

0.

o

lenticularis, Wahlenberg,

. 207,

224

0.

0.

lentifoimis. Hall,

224

0.

o.

Leoneiisis, Hall,

224

0.

0.

Leacoi\a,_Hall,

225

0.

o.

lepida, Hall,

. 207,

0-11

0.

0.

lepida, Schnur,

259,

260

0.

0.

Livia, Billings,

225

o.

0.

Leonensis, Walcott,

222

0.

0.

loiicula, sp. nov.,

. _ . 197,

222

o.

o.

Lucia, Billing!^,

225

o

o

lynx, von Eichwald,

. 202,

223

0.

0

Macfarlanii, Meek,

. 190, 212,

226

0.

0.

Macleodi, Whitfleld, .

224

0.

o.

Maria, Billings,

222

0.

o

in.irmi)rea, Waagen, .

214

0.

o.

Moeki. Miller,

. 206,207,

224

0.

0

Merope, Billings,

242

0

o.

Michelini, Lereille, .

194, 219, 225,

343

0.

0.

niimica,

200

0.

o

Minneapolis, iV. H. Winchell

224

o.

0

Missouricnsis, Swallow,

225

0

0?

Morganiana, Derby,

213, 214, 216,

226

o.

0.

multisecla. Meek,

207,

224

0.

0.

multjstriata, Hall,

212,

226

0

o

niusculosa. Hall,

190,210,211,225,

25S

0.

0

Mycale, Billings, .

217,

232

o.

Nevaclensis, Meek,

226

0

o

Niliis, Hall,

217

0.

o

oblata, Hall,

210, 221,

225

0.

o

occasus, HaU,

235

o.

o.

occidentaliH, HaU,

. 202,

222

0,

0.

Olicierana, do Verneuil,

266

0.

0

Orbignyi, Daiidson,

283

o

0

orthiimbonitiea, Billings,

221,

228

o.

o

Oweni, ftp. nov.,

325

0.

o.

I*anclcriana, sp. nov.,

. cxpl. Plate I

0.

0.

Pecosi, Marcou,

210, 225,

226

o

0

pecten, Dalman,

191

0

0.

pcctinclla, ,A'mmon8, .

,. 196, 196, 222,

22S

0

0.

pectinellu, Emmons, var, ae

miovalis. Hall, 222,

^228

u.

o.

peduncularis, HaU, <

; 226

o.

1 Peloris, Hall,
Penelope, HaJl,
Penniana, Derby,
Pennsylvanica, Simpson,
Pepina, Hall,
perelegans. Hall, .
perveta, Conrad,
planoconvexn, Hall,
platys, Billings,
plicatella. Hall,
porcata, McCoy,
prava, Hall, |
productoides, Murchison,
propinqua, Hall, .
punctata. Hall,
punctostriata,
Quacoensis, Matthew,
quadrans. Hall,
i-ecta, Conrad,
resupinata, Martin,
resupiuoides. Cox,
retroi-.sa, Salter,
retrorsistria,
reversa,

robusta. Hall, .
rugiplicata. Hall, .
Saffordi, s]i. nov.,
Soovillii, Miller,
sectostriata,
Semele, Hall,
senecta, sp. nov.,
eiiiuata. Hall,
sociali.s,
solitaria. Hall,
spiriferoides, McCoy, .
Stonensia, Safford,
striatella, Dalman,
striatula, Schlotkeim,
stroi)humenoide3, Hall,
suba3quata, Conrad,
subcarinata. Hall,
subelliptica, White and Whitfield,
suborbicuIari.s, Hall,
subquadrata. Hall,
8u])erstes, sp. nov.,
Swallowi, Hall,
Swecney'i, N. H. Winchell,
testudiiiaria, Dalman, 190, 191, 192,

tetragona, ....

Thiemii, White,

Tioga, Hall,

triceuaria, Conrad,

tri plicatella. Meek,

Tritonia, Billings,

tubulo.striata. Hall,

Tulliensiii, Hall,

uberis, Billings,

umbraculum, . . . .

Vanuxcnii, Hall,

Vanuxemi, var. pulchclla, Herrick

varica, Conrad,

Wangenheimmi, de Verneuil

Wisbyensis,

PAGE.
. 2-25, 343

211, 225
210, 226

225

230, 232

207, 224

. 207. 224

207, 324

. 218

194, 196, 221

. 197, 222

255

. 317

212, 226
. 217

217

. 232

224

. 822

194, 211, 213, 226

. 213, 226

197, 222
. 203

197
. 262

217
. 218, 3*0

222
. 221

225
. 226

198, 212
. 200

225

. 271

224

191, 305

213

199, 223
. 194, 207, 224

207, 221

225

. 2-25

194,196,197, 341

. 217, 224

213, 226
196, 222, 228

805, 20G, 207, 217

218, 224

219

. 225

212, 226

191, 193, 221

194, 221

. 217, 232

210, 225

212, 226

224

248, 256

225, 342

. 225

. 204, 205, 223

. 319

207

INDEX.

365

Orthis Whitfleltli, X. H. Winckell, .

0. zonata, Dalmau,

O. (Dalmanella) arcuaria, sp. iiov.,

O. (Dalmanell) superstes, sp. nov.

O. (Plresiomys) loricula, sp. nov.,

O. (Uhipidomella), Oweni, sp. uov

O. (Schizoplioria) senecta, sp. uov.

Orthisina adscendetis. Pander.

O. anomala, d'Orbigny,

O. cava, Barrande,

O. crassa, Meek and Haydeu

O. festinata, liilliugs,

O. graiidiBva, Billings,

O. Missouriensis, Swallow,

O. occidentalis, Newberry,

O. orientalis, Whitfield,

0. transversa, Walcott,

O. VerneuUi, Eichwald,

Ortbostropliia strophomenoides ,Hall,

Orthothetes desideratus, sp. nov.,

Orthothetes pecten, Dolman,

O. ladiata, Fischer,

O. socialis. Fischer,

O. subplanus, Conrad,

O. umbraculum, von Buck,

Patella anomala, Muller,

P, antiquus, Schlotheim,

P. implicaia, Sowerby,

Patcrula Bohemica, Barrande,

Pentamerus oblongus, Hall,

Pholiclops autiqua, Schlotheim,

P. bellula, Walcott,

P. calceola, sp. nov.,

P. Cinciunatiensis, Hull,

P. Uamiltonis, HaU,

P. impUcata,

P. lepis, sp. nov.,

p. liuguloides, Hall, .

P. oblata. Hall,

P. ovalis, ^TaW.

P. ovata, Hall,

P. patina, sp. nov.,

P. sp. ? .

P. squamilbrmis. Hall,

v. terminalis. Hall,

P. Trentonensis, Hall,

Plectambonitea crassa, Pander,

P. ohlonga. Pander, .

P. ovata. Pander,

P. planissima, Pander,

P. testadinata, Pander,

P. transversalis, Wahlenberg,

Plicatula striatocostata, Cox,

Polyto3chia apicalis, Whitfield,

Producta analoga, Pbillips,

P. monilifera, McCoy,

P. rugosa, Hi^inger,

P. truncata, Hall,

P. [Triplecia) monilifera, McCoy,

Productella hystricula. Hall,

Pre ductus aequicostatus, Hall,

P. Koniradiatus, Shumard,

P. alternatus, Norwood and Pratten,

P. Altonensis, Norwood and Pratten,

PAGE. 1

2-21

191

341

342

341

31S

343

191,

237

237

271

262

230

231

266

266

230

230

■-'31,

237

200

345

350

256

256

256

259,

345

r22

150

158

15S

79

28S

157,

159

157

157,

183

157,

159

157,

159

157,

159

157

157

157

157

157,

169

188

159

156,

159

157

157,

159

297 ,

208

300

300

96, 297, iSS 1

297

■298,

299

265

239

2S0

270

279

316

271

316

326

326

327

327

Productus Araericanas, SwdUow,

P. arcuatui, HaU,

P. asper, McCkesney,

P. biseriatus, JInll,

P. Burlingtoncnsia, HaU,

P. Clieslereusis, Iforthen, .

V. Christiani, Ue Koninck,

P. cliivus, Norwood aud Vratteii,

P. comoides, Sowerby,

r. complectcns, Ethei^idge, .

P. compressub, Waagcn,

P Cora, d'Orbigny, .

P. costatus, Sowerby,

P. dissimilis, HaU,

P. ermiueus, rfe Koninck,

P. Geinitzianus, de Koninck,

P. genuiuus, Kutorga,

P. HaUianus, Walcott,

P. horridus, Sowerby,

P. Lasallcusis, Worthen,

P. latirostratus, Howse,

P. Leonkardi, .

P. LlangoUensis, Davidson,

P. loDgibpinus, Sowerby,

P. inagnus. Meek and IVorthen,

P. margiuicinctus, Prout,

P. Martini, Sowerby,

P. mesolobus, Phillips,

P. mytiloides, Waagen, .

P. Nebrascensis, Owen,

P. Newlierryi, Hall,

P. aodosus, Newberry,

P. Nystlanus, de Koninck,

P. opuutia, IFaagen,

P. o\atus, HaU,

P. pileilormis, Newberry,

P. Pratteniauus, Norioood,

P. proboscideus, de Verneuil,

P. punctatus, Martin,

P. Kogersi, Norwood and Pratten,

P. scabriculus, Martin, .

P. scmii-eticulatus, Martin,

P. spleudens, Norwood ami Pratten,

P. striatus, Fischer,

P. subaculeatus, Murchison,

P. sulcatus, Castelnau,

P. symmetricus, McChesncy,

P. tenuicostatus. Hall,

P. UTnbonillatus, Davidson,

P. vittatus, Hall,

P. Wortheni, Hall, . .

P. (Daviesiella) LlangoUensis, Davidson,

P. (Etheridgiua) complectens, Etkeridge,

P. (Proboscidella) proboscideus, de Verneuil,

Pronites adscendens. Pander, . . 234,

P. humilis, Pander, ....

P. oblonga. Pander, ....

P. (Clitambonitus) adscendens, Pander,

Raflnesquina alternata, Conrad,

U. expansa, Sowerby,

ttichtiiofenia Lawrenciana, (/e .ffonincA,

Rhinobolus Davidsoni, sp. nov.,

R. Galtensis, Billings, ....

Rhynchonelta angulata, Geiuitz,

263, 325,

326, 333,

PAGE.
.326
327
327
S27
327
327
327
331
318
335
326
326
327
332
334
327
334
332
327
332
320
326
318
332
327
327
325
327
326
327
329
326
334
327
326
326
326
334
327
327

327,

3-25, 327,

326,
3i;

329
332
334
328
250
327
327
320
327
337
317
335
333
237
236
238
238
286
250
154
176
176
217

366

INDEX.

Kocmerella grandis, Tarmxem,

Scenidiam areola, Quenstedt,

S. Baylii, RouauU,

S. devonicum, Walcott,

S. Grayia;, Daiidson,

S. Halii, Safford,

S. insignc, Hall,

S. Lewisi, Davidson,

S. Lcwisi, var. Ilugliesi, Davidson,

S. Lewisi, var. Woodlamlense, Dai-Ulson,

S. MoDllcri, Tscherny^ckew,

S. pyraratdale, i/oW, .

S. Shallockonse, Daiulson,

S. uralicum, Tschernyschew,

Scliizambon ? Canadensis, Ami.

S. ? fissus, Kutorga,

S. lypicalis, Walcott, . Ill

Scbizocrania fllosa, i/«W,

S. ? Helderbcrgia, sp. nov.,

S. Scbucherti, sp. nov.,

Scbizopholis rugosa, Waagen,

Scbizophoria senecia, ^p. nov., .

Scbizotreta conica, Dmght, .

S. elliptica, Kutorga,

Sipbonotreta aculeata, Kutorga,

s.

aiiglica, Morris,

s.

conoides, Kutorga,

s.

fissa, Kutorga,

s.

fornicata, Kutorga,

s.

micula, McCoy,

s.

Minnesoteusis, sp. nov.,

s.

Scotica, Davidson,

s.

Scotica, var. Canadensis, Ami,

s.

tentorium, Kutorga,

s.

unguiculala, ion Eichwald, .

s.

verrucosa, de Verneuit,

Spii

ifcr audacul us, CoKrarf, .

s.

crenistria, Phillips,

s.

hemiplictitus, riiillips,

s.

Lamarcki, Fischer,

s.

senilis, Phillips,

S.3

Waldroneiisis, &liller;ind i>ycr

Streptirf Grayi, Daiidson,

Streptorhytichus cardinalis, VVbitllckl,

S.

Correanus, Derby,

S.

crenistria, Phillips*

S.

crenistria, var. senilis, Phillips,

S.

cusarcus, Abich,

s.

ilalliunus, Derby,

s.

iucurvus, Abich,

s. ?

lepidus, Schnur,

s.

orientalis,

5.

Par\dora, Billings,

s.

peclinirormi.s, Davidson,

8.

pelargonatus, von Schtotheim,

.ST.?

primordiale, WhitUeld, .

S.

I>yramidali8, Newberry,

s.

tenuis. Hall,

s.

Ulrichi, sp. nov ,

Str

opbalosia e.xcavata, Oeinitz, .

s.

Goldfussi, Munster,

s.

Keokuk, Beeclier, .

s.

lamellosa, Geinilz,

s.

I.eplayl, Oeinitz, .

PAfiK. 1

PAGE.

137

Stropl

alosia numularis, Winchell, .

316

242,

213

S.

parva. King,

316

243

S.

plicosa, Waagen,

316

243

S.

radicans, Winchell,

. 316, 320,

335

243

S.

Rockforden.sis, sp. nov..

310,

353

242

s.

scintilla, Beecher,

. 316,320,

336

242

Stroplieodonta arcuata. Hall,

289

213,

243

S.

liecki. Hall,

2S6,

288

243

S.

Blaiuvillii, iJ»7Kn(7S,

iSS

>i

243

S.

Calvini, Milter,

287

213

S.

Canace, Hall and Whitfield,

289

242,

2U

S.

Cayuta, Hall,

289

243

s.

demissa, Conrad,

287, 289,

293

243

s.

fllosa, Davidson,

250

in;.

117

s.

iuaequistriata, Hall,

289

116,

169

s.

Irene, Billings,

288

11, 114, 116,

117

s.

Junia, Hali,

288

143,

144

s.

Leblanei, ....

307

132, 144,

1~9

s.

magniflca, Hall,

. 286,

238

. 143, 144,

179

s.

magniventra, Hall,

,

288

95

s.

nacrea, Hall,

287

212

s.

perplana, Conrad,

2S8,

289

. 13i;,

140

s.

profunda. Hall,

286

\iS.

160

s.

tealWis, Hall,

288

113

s.

Tnllia, Billings,

■288

113

s.

vari.-ibilis, Calvin, .

289

113

Stroplwd^nta striata, l\',\.\\,

291

11, 114, 11.5,

110

S.

fasciata, Hall,

291

113

Strophomena alternata, Conrad,

143, lis.

249

113

S.

antiiiuata, Soicerby,

. 249,250,

252

112,

177

5.

camerata. Hall,

282

113,

115

S.

Chemungensis, Conrad, .

235

115

S.

clausa, de Verueuil, .

2S7

109,

111

s.

Conradi, sp. nov..

344

111,112,

113

s.

deflecta. ....

197

113

s.

depressa, ....

219

118

s.

Dutertrii, Murchison,

249

. 255, 256,

257

5.

euglypha, Dalman,

249

215

5.

expansa, Sowerby,

249

215

S.

explanata, Sowerby,

288

262

s.

filosa, Sowerby,

. 249,

288

272

s.

fluctuosa, Billings,

251

274

s.

funlculata,

249

252

s.

grandis, ....

249

262

s.

MAWia, Miller, .

252

. 256,2.57,

263

s.

Hecuba, Billings, .

232

346

s.

Hendersoni, Davidson,

283

2G3

s.

Holli, Davidson,

283

. 265

268

s.

Julcesi, Davidson,

283

263

s.

Kingi, Whitfield, .

282

. 259

260

s.

Leblanei, Rouault,

287

266

s.

Leda, Billings,

288

255

s.

lepis, Bronn,

287

2G5

263

s.

Minnesotensis, N. H. Winchell,

282

265, 267

268

s.

Narajoana, do V'erneuil,

287

231

s.

nitens, Billings,

283

266

S.l

palma, Kayser,

238

255

s.

patenta. Hall,

■291

. 28S

351

s.

pecten, Dalman,

■249

316

s.

Philomela, Billings,

288

315

s.

planoconve.va, Hall, .

249

251

. 318, 320

330

s.

planunibona. Ball,

249

255

316

s.

recta. Con rati, .

197

310

s.

rhomboidalis, Wilckens, .

247, 248, 249

250

INDEX.

367

Strophomena rugosa, Ilisinger,

5. siiurinfui, Davidson,

S. simiatn. Kinmons,

S, sgnamnta, James,

S. Steini. Kayser,

S. subplaim, ^'Oiivnil,

S. subtenta, Conrad,

S. Thalia. Billings, .

S. Vtrichi, James,

S. unicostata. Meek anil Woi-tli

S. Winchelli, sp. nov.,

S. Wisconsinensis, Whitfield,

S. Woolworthana, Hall, .

S. (Lepla^ua) jjlanumbona. Hall

Stroplwmenes flexilis, Kalinesque,

S. tosviffata, Kalinesque,

Strophonella ampla. Bait,

S. cxlata. Hall,

S. cavumbona, Hall,

S. Conraili, Hall,

S. euglypha, Dalman,

S. luniculata, Sowerby,

S. Ileadleyana, Hall,

S. hybrida, HaU,

S. Leavenworthana, HaU,

S. patenta, Hall,

S. panctulit'eia, Conratl,

S. radiata, HaU,

S. reversa, Hall, .

S. semilasciata. Hall,

S. striata, HaU,

Syntrielasrna kemiplicatum, Hail

Terebratula A7idii. d'Orbigny,

T. Gaudryi, d'Orbiguy,

T, Michelini, d'Orbigny,

Terebratulina septentrionaiis,

Terebratulites biforatus,

T. . pelargouatus, von Schlotheim, .

T. (Schizocrania) superinci'eta, Barrett,

■25U,

4S,

:51, -52 Trinierelia acuminata. Billings,

2SS
. 251

28!
. 2S8

255
. 251

251
. 283

282
344

251
. 255
•219, 252

219,
24S,
291,
291,

291,
291,
291,

291,
291,
291.

200,

252
252
293
293

T. Billingsi, Dall,

T. Dalli. Davidson ancl King,

T. grandis. Billings,

T. Lindsti'oeini, Dall,

T. Oliioeasis, Meek,

T. Wisl)yensis, Daridsoji and King,

Triplecia extans, Emmons,

T. Oi-toni. Meek,

Triplesia cuspidala, HaU,

291, 292

292

250, 292

250, 292

293

292
292
292
292
293
292
292
216
217
217
217
16
202
267
\U

Grayia;, Davidson,
IVIaccoyana, Davids<fn,
nucleus. Hall,
primordialis, U'liittield,
putiUus, Hall,
radiata, Whitfield,
Wenlockensis, Davidson,

T?

T. V
T.
T.
T.

T.

T.

Trematis Bohemica>, liarrande,

T. cancellala, Sowerby,

T. corona, Salter,

T. crassipuncta, Vlrich,

T. Dyeri, Miller, .

T. I'ragilis, Vlrich,

T. Iluronensis, Billings,

T. miUepunctala, H<dl,

T. Jlontrealensis, Billings,

T. oblata, Vlrich,

T. Ottawaensis, Billings,

T, ? pannulus. White,

T. punctata, Sowerby,

T. ])nnct03triata. Hall,

T. i)ustulosa, HaU,

T. ijuincuncialis. Miller aud Dyer,

??T. rudis, HaU,

T. terminalis, Emmons,

T. umbonata, Vlrich,
Tropidoleptua carinatus, Conrad,
Volborthia recurva, Kutorga,

I'AGK.

35,

36

35,

36

34, 35,

36

34,

36

34, 35.

3ft

36

TO, 271,

273

68, 270,

271

271

270,

271

270

271

271

272

271

270

40,

142

142

Hi

142

112

142

142

l:!'J,

142

142

142

139,

142

94

141

142

142

142

142,

114

139, 141),

142

139

143

95

REPRODUCTIONS OF DALMAN'S PLATES I AND II.

Accoinpaiiyiiig- his paper entitled : " Uppstalling- och Beskrifning at' <ie i Sverige funne Terebratiiliter.

See Page 193

" EXPLICATIO FiGURAKUM :

Till). I. Fig. 1, Lkit^na rugosa His.

Fig. 2, a, b, Lept^na depressa Sow., c, ejusdem Var. ; d, valva intus visa ; e, valva altei'a in-

tus visa, cum dentibus carditialilms ; — f, margo cardinalis ; g, sectio ambarum loiigi-

tudinalis, a latere visa, ut reprsesentaret valvas compressas et angulum, quem format

margo reflexiis.
Fig. 3, a, Lept^ena euglypha : 3, b, eadem a latere visa, inagn. nat. — 3, c, stria; in testa ele-

vatiB, cum interstitiis undulatis, iiiagn. aact.
Fig. 4, a, b, Lkpt.bna transversalis : magn. nat. — 4, c, d, eadem viagn. auct.
Fig. 5, a, OuTHis striatella : valva major; b, figiira hujiis valvje convexitatem reprssentaus.
Fig. fi, a, Oktiii.s Pecten : valva major, — b, valva altera ; c, valva; majoi-is sti-ia;, magn. auct. ;

d, valva; alterius ."triEE, magn. auct.

uj-Aii>ij-ii~^f'3 j^ij-:rii"ij:i"A ca'A s njicAHA.

? /,

'Z /'

S d.

J A

// ./

6d.

fi-A

" ExPLICATIO FiGURAKUM.

Till). II. Fig-. 1, a, Okthls zonata, valva major, retusa; b, eadein, valva minor; c, d, e, eadem species a

basi et a lateralibiis visa.
Fig. 2, Ortuis callactis a.
Fig. 3, a, b, c. <i : Ohthis calligramma.

Fig. 4, a, b, c, d, Orthis testudinaria ; — 4, e : sulci cum striis, inagii. auet.
Fig. 5, a, b, c, d, e : Orthis basalis
Fig. 6, a, b, c, d : Orthis elegantula; — 6, e : hujus sjieciei valva majoi- intus visa ; fi, f: valva

minor intus visa ; g, valva minor a basi visa, ut repriEsententur denies cardinales.
Fig. 7, a, b, c, d : Orthis demissa."

TjjA.iiVJ^\i'^r£) :p:i:;-'j-'jiJji£-i^\.iia-'A .3 L/^uArrA.

/a

/-/

/ ^

ii.

O (.

3 </.

5^'// -•^^■

f/mm

-S^o-

V ^

■/ c.

V ./

■^ r.

s /,

^^

<0^fj;^

.5^^.

.^ ^

ff a.

6 i.

G «.

7 a.

i

7 c.

7 <^

-m 6/^

"^T^l^ o^

' P^IfridTi 'ici

PLATES AND EXPLANATIONS.

Legfentl. g. Umboiial wjirs.

1. Lateral s<-ai's.

k. Sliddle laterals.

j. Anterior laterals.

1. Outside latei-als.

X. Concrete latei'als.

h. Central scars.

PLATE I.

c. Concrete centrals,
i. Transmedian scars.

d. Carilinal area.

s. Median seiitnni._
s'. Latei'al septa,
vs. Vascular trunks.
V. Vasculai- branches.

LINGULA, Bruguiere.

- - Glossi.\.\, Phillips.

I'age l."i.

LiNCxULA (Glossina) ACUMINATA, Coiiracl.

Fiir. 1. A i)ediele- valve from which most of the sulisfance of the shell has been exfoliated, presenting' a
c.'isc (if the internal surface,. which retains the inijiressions of the tine radialinf^, and coai-ser,
more distinct, concenti'ic lines. The thickness of the shell-sulistance and the undulating char-
acter of its laminae, is .shown on file margin;il portion of the figure, but no traces of muscular
impressions are discernilile. X 2.

Fig. 2. A lirachial valve of the same species, from which the shell is partially exfoliated. X '-i.
Calciferous sandstone. SamfiM/a, iV. 1'.

LiNGCLA (Glossina) iuciniformis, Hall.

Kig. :i. .\ ]iedicle- valve (?) from which the outer layers of the shell are somewhat (sxfoliated ; showing the
strong median I'adii, which are evidently moi'e distinctly developed on the intei'ioT' than on
the exterior of the shell. X 3.

Trenton limestone. MiddlfTiUr, JSf. Y.

LiNGULA Vanhounii, Miller.

Fig. 4. Tlie interior of a pedii'le-valve ; showing the undifi'erentiated lateral iiiu.sciilar scars, and the low,
median sejitum. X 3.

Hudson River group. Cinriimaft, OIi'hi.

LiNGULA Phocteri. Uii'ich.

Fig. .'). The brachial valve of an internal east : showing the concrete laterals (x), the anterior laterals (j),

and the septum (s). X 1.5-
Fig. 13. The o)>poi3ite valve of the same specimen ; showing the progressive lateral and median impres-
sions (septum) and the vascular markings. X L5.

Hudson River' group. South (hmiKjUin, Ki"ii.tiicky .
Fig. 7. An internal cast of a bi-achial valve ; showing the lateral scai's and long median septum. X 2.
Hudson River !gi-oup. Chic'ninali. Ohio.

LiNGULA Philomela, Billings.

Fig. S. A peilicle-valve ('.). imperfect in the umbonal i-egion : illustrating one extreme of outline attained
liy shells of this g(inus. Natural size.

Trenton limestone. FlorencevUh , Houxird munty. Imoa.

LiNGULA LAMELLATA, Hilll.

Figs. (I, 10. F,xternal and internal views of the same specimen. Natural si/e.
Niagara grcnip. Tjockport, N. Y.

LiNGULA CUNEATA, Coilfiul.

Fig. U. An internal cast of the jiedicle-valve ; .showing the broad, low, median septum and the faint lateral
scars. X 2.

Fig. 12. The brachial valve, with an ill-detiru'd muscular scar and traces of the vascular sinuses.

Medina sandstone. Albion, N. Y.

PLATE I— Continued.

LixGULA QUADKATA (Eichwakl), Hilll.

Fig-. 13. A large example, from which much of the shell has been exfoliated ; showing- the median septum,
which i,s frequently more strongly developed, and the projection of the undional region of the
pedicle-valve beyond the? apex of the braehial. The prominence of the lattei- feature is to some
degree due to the displacement of the valves.

Trenton lime.stone. Trenton Falls, N. T.

LiNGULA loWENSIS, OwCll.

Fig. 14. The interior of a brachial valve, probably referable to this species ; showing th(! conspicuously
developed median septum, the well-detined central .scars (h), ami the progi-e.s.si ve laterals (x).
Natural size.

Gralena limestone. Fmmtain, Minnesota.

LiNGULA SPATULATA, VilllllXem.

Fig. 13. A peilie.le-valve (?), retaining the shell, and showing evidence of a median aeptnm in the iimbonal
i-egion. X 6-

Genesee slate. Canandaigita Lake, N. Y.

LiNGULA CO.MPTA, sp. IU)V.

Fig. 16. A specimen of the brachial valve (?) ; showing the lateral imiires.sions ami the median septum ex-
teniiing to the anterior margin. X 2.

Hamilton shales. Canandaiffiui Lake, X. Y.

LiNGULA COMPLANATA, WllliaillS.
Fig. 17. The interior of a brachial valve; showing the fulcra of the lateral muscles. X 2.
Portage group. Ithaca, N. Y.

LiNGULA .s|) ? cf. Cuyahoga, Hull.

Fig. 18. A i)edicle-valve, retaining a poition of the shell-substance, and showing the position of the lateral
scars. X 2. .

Chemung grouji. Panama, N. Y.

LiNGULA anatina, Laniiiick.

Fig. 19. The inteiior of the pedicle-valve ; showing the character of the muscular scai-s and sejpla .-u-; they

appear when the musculai- bands and the mantle are wholly removed. Natural size.
Fig. 20. Brachial valve of the same. Natural size.
Recent. Philippine Islands.

LiNGULA Elueri, Wliitficld.

Figs. 21. 22. Copies of the lithographic tigures given by Mr. Whitfield (Geol. Sui'v. Wisconsin, vol. iv, pi. 27,
tigs. 4, 5), of the interiors of the pedicle anil brachial valves, lespectively. Drawn from a cast
which preserves the internal charactei-s with remarkable completeness. X 2.
Trenton limestone. Near Rochester, Minnesota.

LiNGULA Cf. DENSA, Hall.
Fig. 23. The interioi- of a pedicle-valve ; sliowing the septum and lateral scai-s. X 2.
Hamilton shales. Centerfield, N. Y.

DIGNOMIA, Hall.

Page H.
DiGNOMIA ALVEATA, Hall.

Fig. 24. A cast of a brachial valve ; showing the long, sharp median septum ami the fainter diverging
lateral septa. Natui-al size. '

Hamilton shales. Fultonham, N. Y.
Fig. 25. A portion of the interior of a large pedicle-valve (l), with a shorter and broailei' median septum,
and distinct lateral septa. Natural size.

Hamilton shales. CanandaigiM Lake, N. Y.

PLATE I— Continued.

LINGULA, Bruqui^re.

Page 2.
LiNGULA PUNCTATA, Hall.

Kig-. 26. An onlai-^ement of the external surface; showing the character of the ornamentation. X 12.
Fig. 27. A cast of the interior of the bi'achial valve; showing- the indistinct lateral scars, the vascular

sinuses and their ramifications. X 2.
Kig. 2S. An internal Ciist of a pedicle-valve ; showing' the compound lateral scars and the bi-oad centi-als

X 2.

Hamilton shales. Canandaigua Laki, N. Y.

LiNGULA Delia, Hall.

Fig. 29. The type-specimen, a brachial valve (?), retaining most of the surface ornamentation, and showing
a very strong median septum. X 2.

Hamilton shales. Canandaigua Lake, N. T.

Ll\gula SCUTELLA, sp. UOV.

Fig. 30. An internal cast, indicating that the muscular region of the valve was depi-essed. instead of thick-
ened and elevated as usual. X 2.

Chemung group. Alleghany county, N. Y.

LiNGULA WhITII, Wlllcott.

Fig. 31. A cojn' of Mr. Walcott's figure of the bi-achial valve of this species (Palseont. Eureka District, pi.
xUi", fig. 3). X 2.

Lower Devonian. Atrypa Peak, Eureka District, Nevada.

LiNGULA Melie, Hall.

Fig. 32. A valve, showing the bi-oad, low median septum, with its elevated margins. X 2.
Waverly group. Berea, Ohio.

LiNGULA (GlOSSINA) FLABELLULA, Sp. IIOV.

Fig. 33. A very lai-ge example, from which a portion of the shell has been exfoliated, without showing
any traces of muscular markings. The anterior margin is represented with too great a
curvatiu'e. Natural size.

"Waverly group. Seiotomlle, Ohio.
Fig. 34. A smaller valve, exposing the inner laminse of the shell, with faint radiating lines. Natui-jil size.
Berea grit. Bei-ea, Ohio.

LINGULEPIS, Hall.

Page 59.
LiNGULEPIS PINNIFORMIS, OvVeil.

Fig. 35. An internal ca.st of a jiedicle-vidve : sliowing the faint median septum, and the elongate musculai-

.scar, with its lateral and central divisions. X 2. ,
Fig. 3t). An internal cast of the brachial valve, in which the muscular impression is fiabellate, the centi-al

and latei'al scars being ipiite distinct, the latter somewhat bilobed. X 2.
Potslara sandstone. I''alls of the iStt. Croix, Minnesota.

::i33i^:E3I3r)iF B m JS. .

Ci rn*- r 1' Illn ^I i-ijliun;;

Palaeom >J Y VollVPt n =Vol Vm.

\

\ -r

m

^<f

^%k

^^^i^^

^:

M

20

24

M

■0/

»ii|

^^'

35

jL.hJmmoi',? ,1^;

FnilAsilitK.

PLATE II.

Legend. ?. Umbonal scars. j.. PedicK-gro'nve.

<• Cardinal scans. ,,s. Pedicle-sheafb.

I Latera scars. ,i, cardinal area.

h. Centra scai«. cc. Cardinal callosities.

'■• Umci-ele centrals. pi. Piatfonn.

z. External scars. .,. Median septum.

h. Parietal scar. vg. Vascular .sinu.ses.

cr Urescent. ,

LINGULELLA, Saltkk.

Page 55.
LiNGULELLA CiELATA, Hall.

Fig. 1. A pedicle-valve, from which the .shell is partially exfoliated ; showing fiWeS 6f' the curved lateral
ami Ihe central scars. X 2- I : i '^'"= ^"y*"' 'aiei ai

Fig-. 2. A pedicle-valve, refaininjr most of the shell; showing- the surface ornamentation a,„l ih..

^^loir 'x 2""' ^^^ '""^""'■"'^' ^^'"'""- ^"^"""'^ '"^ «--atio;":m;::Hr (l./l;sS5:

Pig-. 3. A brachial valve ; showing fhe'central and lateral muscular imiiiessions and a '<-a,.i. .ii,«^i, a i
fined scar (z) which, if not adventitious, may he homologous with the ^'x^.nals^si^^i^/,^
cros-s-rt, or the terminal crescent .scai-s in the Trini."rellid.s. x 2. '»■ "(-ai .s in coo(,.«a

Vig. 4. An incomplete cast of the same valve. X 2.

Middle Cambrian. Wear Troy, N. Y.

LiNGULELLA Dawsoni, Matthew.

Pig. 5. A cast of the interior of the pedicle-valve. X 3.

St. John group. Portland, New Biiimwhli.

LiNGULELLA (?) palijformis, Hall.
Pig. 6. A view fi-om the dorsal side of both valves in normal juxtaposition ; showing the clevition of the
cardinal area m the pedicle-valve, and its pedicle-slit, which by comnreslionl ,?p. f 1 1

the exfoliated apical portion of the bra<:hial valve. , X 2. t-omp. e.ssion appears through

Hamilton shales. Shurger's Glen, Cayuga Lake, iV. T.
Fig. 7. A pedicle-valve , showing a faint slit along the position of the pedicle-groove. X 3

Hamilton shales. Pratt's Falln, Oiwndaga amnty, N. T.
Pig. 8. A jiedide-valve, which has been compre.ssed along the tilling of the pediele-slit. X 3

Hamilton shales. S/iurger's Glm, Cayuga Lakr. N. Y.

LiNGULELLA Stoneana, WiiiUield.
(Lingulella aurora, var.. Hall.)
Fig. 9. Dorsal \'iew of a specimen. Natural size.

Fig. 10. The same, enlarged to three diameters : showing the characters of the cardinal -vrea
Fig. 11. An^enlai^ge^uent of the surface ; showing the concentric growth-lines crossed by undulating lamel-

Potsdam sandstone. In thettpper, mriegated magnesian layers. „.nr yTazomanie, Wis.

LiNGULELLA AUHORA, Hall.
Fig. 12. A doi-sal xiew of the specimen ; showing the high cardinal area, and its pediele-groove v M
Fig. 13. Another specimen, similarly enlarged. • ^ . •

Potsdam sandstone. Near Mazomanie, Wucmisin.

PLATK II— Contiiiueil.

BARROISELLA., geii. uov.

Page 62.

Bakhoisella subspatulata, MecU ;uul WdiIIicii.

Fi". H. The <-iU-ilinal portion of the pedicle-valve ; showing- the conspicuous pedicle-gi'oove, whicli, in this
" instimce, has been somewhat widened by compression and fracture ; also the articular Ixisses

or <;ar<linal fulcra on the basal margin. X 5.
Fig. 15. The interior of a pedicle-valve ; showing the cardinal area, nuiscular and other markings. X 3.
Fig. 16. The inteiior of a brachial valve, with characteristic features. X 3.

Ulack slate (Genesee slale). IVhife mivi; near Ruckford. Tndinna.

LINGULASMA, Ulkicii.

Page 24.

Linoulasma Schuoherti, Ulricli.

Fi"-. 17. The apical p<ii-tion of the internal cast represented in tig. 22 ; enlarged to show the impression of
the pedicle-sheath (ps), or internal continuation of the cardinal area. X 3.

Fig. 18. The interior of a brachial valve ; showing the character of the musculai- imjii-essions, the platform
and the very strong septum. Di-awn from a gutta-percha impression of an internal cast.
Natural size.

Fig. 19. Profile view of an internal cast ; showing the relative thickness of tlie platforms on the two valves.

Fig. 20. The intei'ior of the pedicle-valve ; showing the pedicle-slieath (ps), the indislinctly detineil muscu-
lar impressions, the low platform and inconspicuous septuTU. This drawing is also made from
a gutta-percha impression. Natural size.

Fi". 21. An enlargement of th(' surface ornamentation. The tubercles are sharply defined, and round on
the median jiortions of the shell, but become elongated and less distini.'t toward the lateral mar-
gins. X 5.

Fig. 22. A natural cast ; showing the intei-ior of the brachial valve.

Fi"-. 23. The opposite side of the same specimen; showing the intei-iiMl char.acters of the pedicle-valve.
Hudson River group. Wilmington, lUinoiH.

LfNGULOPS, Hall.

Page 18.

LiNGrLOPS NoRWOODi, James.

Fig. 24. The exterior of a pedicle-valve. X 4.

Fi". 2.5. The interioi' of a pedicle-valve, drawn from a gutta-percha imin-ession of a natural cast. The

pedicle-groove is faint but evident : within the broad po.sterior margin lie the compound um-

bonal or cardinal impressions ; the scalloped posterior and the median muscular scars are very

sharply defined. X 8.
Fig. 2H. The interior of a brachial valve ; showing the low, elongate platform. The punctEe on the .surface

of the platform ajipear to be regularly arrangeil liiit are jirobably accidental markings.

Drawn from a gutta-percha impression. X 6.

Hudson River group. Vincimiati, Ohio.

LiNuuLOPs Whitfieldi, Hall.

Fig. 27. The extei-ior of a peiiicle-valve. X 0.

Fig. 28. The interioi- of a jiedic^le-valve ; the original sjiecimen. The figure has been drawn from a gutta-
percha impres-sion of an internal cast, and shows the comjmund cardinal ai-ea (seen also in fig.
30), the \\\m:v portion of which is concentrically striated ; the crescent (rr) ; the scalloped pari-
etal scar and mi'dian muscular scars ; the narrow longitudinal septum Hanked by broad, ronndeil
ridges continued from the visceral region. No traces of vascular impressions are visilile on
the specimen. X 12.

Fig. 29. An imperfect interior, i>n)h!it)ly belonging to the same (pedicle-) valve. X 12.

Fig. 30. The interi(n- of the brac-hial valve, drawn from a gutta-pei-cha impression ; showing the double
car<linal area, a faint pedicle-deiiressinn, the crescent (cr), the ]iaric!tal (0 scars, the platform,
and the va.scular .sinuses with their outer ramifications. X 10.

HiKlson River group. Maquoketa Creek, 12 miles north-wst of Didmque., lawn.

:i3:H^D!lii£D^£'iiJ^

(i r II ri H lUiistrali'i

Palaeont.NYVol lYPt li =Vol Vin.

Platen ,

"LEmicons

phil.Astlitk.

PLATE II— Continued.

OBOLELLA, Billings.

Page (iii.

Obolella crassa, Hall.

Fig-. 31. The exterior (li !i valve. Natural size.

Fi"- 32. The same, enlarged ; j-howin- the radiati,,- st,-ia; between the lamellose -i-o«th-ln,es. X -. _

■ Fig. 33. Another valve, similarly enlar-e.l, in whi.-h the radiali,;^' lines do not appear Tins ,s the speci-
men ori-inally descril)ed as Avicuhi dcsqaamata. Hall (Pal. N. > ., vol. i. 1M7).

Fig-. 34. The interior of a pedicle-valve ; shonin- the pediele-g-roove, the car.linal. lateral and (-ent,-al mus- .
cular scars. X 2.

Fi"- 35 The interior of another, but .smaller, pedicle-valve ; showing: the same teatures. X -.

Fig. 36. The interior of the brachi.al valve; shoNvin.-thefai.it pedicle-g-roove, the caninial, exte,-na,l, cen-
tral and 1,-itei-al muscular impressions. X ii-

Middle Cambrian. Near Troy. N. T.

Obolella polita, Hull.

Fig. 37. The exterior of a valve, X 4. ■■ ^ ,

Fig. 38. The interior of a pedicle-valve ; .sliowing the central and lateral n.usrnlar nnpressions. X -
Fig. 39. An internal cast of the opposite (!) valve. X 2.
Fig. 40. The interior of a brachial v.alve X 6.

Fig. 41. The interior of a pedicle-valve. X li- , „ . ^r v ^. .

(Figs 40 and 41 are from the origi.,.-d drawings represents m the Sixteenth Kept. N. V. State
Cab, Nat. Hi.st.. pi. vi. tigs, 20, 21.)

Potsdam sandstone, Trtmpahaii, Wisconsin.

Or.OLELLA GEMMA, Billillg.S.

Fig. 42. The exterior of a pedicle-valve. X tj. .

Fig. 43. (34 in error, last line of figures.) The interior of a brachial valve ; showing the muscular un-

pressions. X 6. ,. , • j i •

Fig. 44. The interior of a pedicle-valve ; showing the ,-ai-dinal area, pedicle-groove and muscular un-

(Tte orS^s ^ lis. 1. 2, 4, 34, 35. 30. 42. 43, 44, are in the collection of Mr. S. W. Foko.)

PLATE III.

TjffjcMnl. I. Latinals.

c. Centrals.

sc. Suboardinals oi' jjostmcdians.
v.v. Crescent.

e. Externals.

X. Composite i>osterioi-s.
P. Pedicle-gi'oove.
F Foramen.

t'. Forauiinal pits.

-s. Septum (median),
s'. Septum (lateral).
o. Vascular trunks (oviducts?).
d'. Subapical area,
cb. Cardinal bosses.
fc. Foramina! callo.sity.

LKPTOBOLUS, Hall.

P.ige 73.
LePTOBOLUS IN.SIGNIS. Hall.

[■"ij.'. -1. .'\n internal cra.st df a jiedicle-valve ; showing- the \cmg, cni-ved lateral scars and a faint indii-atinn

ot the piisterioi' mn.s( ular depiession. X H^.
Flu-. '2. Aw internal ifast of the brachial valve, .similarly enlarged, and showinfr the median septum and

two lateral grooves, which cdricspond either to the scars (z) seen in tig. (i, or to the lateral septa

(sO in tig. 10.

Utica sl.ite. Holland Patent, JV. Y.
l'"ig. 3. The exteiior nf the shell ; showing the concentric and radiating striie. X S.

Utica slate. Middlevillt, jV. 1'.
Kiir. 4. The interior of a pedicle valve ; showing the cai-dinal area ami groove, and the thick, eallouseil

fulcra of the lateral muscles. X IS.
Kig. 5. Ajiothei- interior of this valve, in which the transverse extensions of the lateral fulcra are <-.(intinu-
cius. The iiosti'i'i<n' dei)res.se<l ai-ea bears the impression of the centi-al muscles, and indications
of a subdivi.siou of the pitted su;face into dift'erentiated scars. X 15.
Fig. ti. The interior of a brachial valve : showing the gi'Ouved ai-ea, conspicuous median septum and faint
latei-al scars.

Hudson Rivei- group (Utica horizon). Cimtigion, Kentucky.

Leptobolu.s occidentali.s, Hall.

Fig. 7. The exterioi- of the ."ihell. X S.

Hark shale of the Utica hoi-izon. Hnwhy'f: Mill, 12 miles north-west of JJiiAmque, Iowa.

Leptobolus lepis, Hall.

Fig. S. The interioi- of a [ledicle-valve ; showing the cardinal groove and the diverging .septa. X 12.
Fig. n. A cast of the interior of the pedicle-valve ; showing the central scar and the transvei-se extension

of the laterals. X 12.
Fig. 10. The interior of the brachial valve ; showing the grooved cardinal .-irea and the median and latei-al

se]ita, each of which is bifurcate at its extremity. X 12.
Hudson River grouji. Lickinfi liivt-r, Ohio.

SCHIZOBOLUS, Ulrich.

Page 87.
SCHIZOBOLUS TRUNCATUS, Hall (^p.).
Fig. 11. The exterior of a pedicle-valve. X 3.

Genesee slate. WealKrn New York.
Fig. 12. The interior of a jiedicle-valve, drawn from one of Mr. Ui.iuch's original si)ecimens; showing the
pe<licle-slit, the comj)Osite muscular scars abidting against the median septum, and the long,
curveQ lateial seal's. X 5.

Black slate (Genesee). Madisan county, Kentucky.
Fig. IS. The extei-ior of the bi-achial valve. X 3.

Gene.see slate. iVe.'itern New York.
Fig. 14 The interior of the brachial valve ; showing the septum and faintly defined muscular iinjires.sions.
X •').

Ulack slate (Genesee). Madison county, Kentucky.

113 1S3.^:^SI2®I? ®2B^

<i|-UCI 1< Illusll-.ill.JIlt

Palffiont N Y.Vol IVPtii'Vol VIll

Plate III

^^:;i 1

E. Emmons 'lei

PhilAslktJi.

I'l.ATli 111— Lonllnucl.

ELKANIA, FoKi).

Page 75.
Elkania desiderata, Billings (sp.).

Fig. 15. The interi<ir of a. pedicle-valve ; showing- the deep central iinpi-es'si<in (pedicle-pit cif Fdku), snb-

cardinal, crescentic and external scars, the divei'ging vascular (genital ?) furrows and the liroad,

deep lateral depressions, prohalily not of nniscular origin. X ii-
Fig. It). The counterpart of the same, similarly enlai-ged.
Pig. 17. The interior of the bi'achial valve, with the impressions of the central aiid latei-al muscles and

crescent. X 3.
Fig. 18. The counterp.art of the same ; showing the muscular callosity or incipient platform. X •!■
Fig. 19. An enlargement of the surface of one of the intermediate corneous layei's of the .shell ; showing

its irregularly granulose surface. X 6.
Quebec gi'oup. Pointe Livix.
The above figures are made from Mr. E. Billinus' original specimens of the species.

DISCINOPSIS, geii. uov. (Matthew).

Page 105.

DiSCINOPSIS GULIELMI, MuttlieW.

Fig. 20. The exterior of a pedicle- valve ? ; showing the radiating ami concentric lines, ami a Haltened apex
which may indicate the position of the foramen. X f>.

Fig. 21. The interior of the pedicle-valve, with the linguiform median extension .sharply detincd. and show-
ing the possible position of the foramen. X •').

Fig. 22. The connteriiart of the same. X S.

Figs. 23, 24. Other interiors of the pedicle-valve, less satisfactorily pi-eserved. X 5.
All are from the St. John group. Portland, JS'ew Byunxioick.

ACROTFIELE, Linnarsson.

Page 9S.

AcROTHELE Matthewi. Hiirtt (~p.), var. prijia, Mutliiew.
Fig. 25. The exterior of the pedicle-valve ; showing the chai-acter of the sui'face ornamentation. X •'!•

AcROTiiELE Matthewi, Hiutt, v:ir. lata, Matlhcw.

Fig. 26. The interior of the pedicle-valve ; showing the position of the foramen and the foramina! pits. X 3.
Fig. 27. An internal cast of the same valve. X 3.
Pig. 28. Pi-ofile of the latter. X 3.

St. John group. Hcmford Brook, New Brunswick.

ACROTHELE Matthewi, Hiirtt (.>!).).

Fig. 29. The interior of a bra<-hial valve ; showing the median septum and adjacent muscular scai-s. X 3.
St. John group. Portland, New Brunswick.
Figs. 25 to 29 are from the original specimens figured by Mr. Matthew.

ACEOTHELE SUBSIDUA, White,

Pig. 30. 'I"he interior of the jiedicle-valve ; showing the foramen and foramina! jiits. X 2.
Fig. 31. The interior of the brachial valve with a faint meilian septum. X 2.
Middle Cambrian. Antelope Springs, Utah.

PLATE III— Continued.

ACKOTRETA, Kuxorga.

Page 101.

AcROTRETA Baileyi, Miitthew.

FifT- 3'-3. An inteinal cast (if a peilicle-valve ; showing' the grooveil subajiical area and the impression of
the nipple-like swelling surrounding- the foramen. X 4.
(Matthew, Trans. Roy. Soc. Canada, 18S3, pi. iv, fig-. 13c.)
Fig. 33. An internal cast of the brachial valve. X 4.

(Matthew, op. clt., tig. 13.)
Fii'-. 34. The exterior of a pedicle-valve ; showing the size of the outer foraniinal aperture. X 4
St. John group. Lo7Uj Reach, Klnc/'s county. New Brunswick.

LINNARSSONIA, Walcott.

Page 107.

Linnarssonia miseua (?), Billiiig.s (»!>.).

Fig. 35. An internal ca.st of a pedicle-valve : showing the impressions of the cardinal bosses and the
foramina! callosity. X 6.
(Matthew, op. rit., fig. 12c.)
Fig. 36. An internal cast of a brachial valve. X 6.

(Matthew, op. cit., fig. 12.)
Fig. 37. An intei-nal cast of a pedicle-valve. X (>.

St. John group. Porter's Brook, St. .John county, Neir Brunswick.

Linnarssonia transversa, Hiirtt (.sp.).

Fig. 3S. An internal cast of a pedicle-valve; showing the inner foraniinal aperture, the impressions of the
foraniinal callosity and cardinal tubercles. X o-

(Matthew, op. cit., tig. lie.)
Fig. 30. The counterpart o'f the same. X 1'^.
Fig. 40. An internal cast of the brachial valve. X 5-

(Matthew, op. cit., fig. 11.)
Fig. 41. Posterior view of the same. X ».

Fig. 42. The counterpart of the same; siiowing the median and lateral septa and the large postei'ioi
scars. X in.

St. John Group. Forter'.s Brook, St. .Talin connty. New Brmiswick.

Linnarssonia pretiosa, Billing.s.

Fig. 43. The interim' of a pedjcle-valve. X 6.
Fig. 44. The interior of a brachial valve. X 6.

(See Dawson, Trans. Roy. Soc. Canada, vol. vii. Sect, iv, p. 53. 1889.)
Qnebet- gi'ouj). Island of Little Metis, Province of Quebec.

PLATE IV.

Legend. x. Coniiiosite latei'als. F. Foramen.

c. Composite centi-als. P. Peilide-gfroove.

cd. Cardinal ridge. S. Sipho. ^ ■

KEYSERLINGIA, P.andkr.

Page 117.

Keyserlingia Buchi, Vcnicuil.

Fig. \. The interior of a pedicle-valve ; showing the depressed or broadly grooved cardinal area, pci-for-

ated by the opening of a sipho which is blind at its innei- termination.
Fig. 2. The interior of a brachial valve; showing a blind internal tulie, which is represented as V)rok(m,

the cavity ai>|iearing in cross section.
Fig. 3. The exterior of the pedicle-valve ; showiTig the slit-shaped opening of the pedicle-passage.
Obolus beds. River Ischora, Russia.
The above figures are cojjies of those given by Pander (Bull, de I'Acad. Imp. des Sciences de St.
Peter.sbourg, vftl. iii, p. 46, pi. ii, figs. 1, h, c, a), and represent the peculiar features assigned
by him to the genus. The views are considerably enlarged.

HELMERSENIA, Pander.

Page 119.

Helmer,seni.a, Sp. ?

Fig. 4. The interior of a pedicle-v.alve. The cardinal area is broail .-ind liears a median deprpssion-or
deltidium, as if for the pa-ssage of the pedicle.

Fig. 5. The exterior of a similar valve ; showing the apic.il apertuie which, according to Pander, is
atrophied and blijid.

These figures are also taken from the work of Pander cit<'d above (figs. 2 <\ and 1>. respectively),
and the fossils are from the same beds ajB those of Kevsert.ixcua.

IPHIDEA, Billings.

Page 97.
IpHIDEA Cllf.? ORNATELLA, LillllursSOl).

Fig. 6. A pedicle-valve, somewhat imperfect about the anterior margin, but showing the snbapical area
and the very broad cardinal ridge (" pseu<lo-deltidium," Billings). X 3.

Fig. 7. Profile of the same ; showing the height and curvature of the posterioi' ridge and its basal ele\'a-
tion. X 3.

Tonto group. Grand Carion, Arizmta.

IpHIDEA BELLA, Billiiigs.

Fig. 8. A pedicle-valve in which the snbapical area is relatively small; showing the pi-ominence of the
cardinal lidge and the position of the foramen, which is not altogether distinct in the speci-
men. The figure is .also slightly restored about the edges whei'e the original is somewhat
broken. X 3.

Fig. 9. Three-quarter view of the same, giving the elevation of tlie shell and the size of the cardinal
ridge. X 3.

Geoi'gia group. Georgia, Ven/umt.

PLATE IV'— Coiuinaeil.

KUTORGIXA. Billings.

Page ao.
KUTOKGINA CINGULATA, BillillgS.

Fig. 10. The ped'u:le-val\e of an example with a low, scarcely incurved l)eak. X 2-

Fig. 11. The brachial valve. X 2.

Fig. 12. Profile of a peilicle-valve from which the shell is largely removed ; showing the degree of incurv-
ature. X 3.

Fi'^. 13. A pedicle-valve with a strongly incurved umbo; drawn from an internal cast. X 3.

Fig. 14. Profile of the same. X 3.

Fiu". li). A brachial valve : drawn from a gutta-percha impression of a natural mould of the exterior.
Natural size.

Fi"'. IS. The interior of a In-achial valve ; showing the radiate ornamentation of the surface and the faint
muscular ridges near the beak. X 2. ' ' ' ■ ■ . - ■

Fi". IT. A brachial valve in which the cardinal margin is not transverse, as in the other examples fig-
nved, but is strongly reenti'ant. X 2.

Georgia group. Swanton, Vermont.

KuTORGiXA Latourensis, MuUIr-w.

Fig. 18. A i>edicle-valve ; drawn from a gutta-percha cast from a natural mould of the exterioi-. X U.
Fig. 19. Profile of the same. X tj- .m .u ■

Fin-. 20. Cardinal view of the same; showing the open triangular fissure. X 0.
St. John group. Portland, New Brunswick.

MESOTRKTA, Kltouga.

Page 109.
MeSOTRETA TENTORIUM, KutolWl.

Fi"-. 21. The pedicle-valve ; copied from Kitouoa's work, Uel)er die Brachiopoden-faniilie der Siphono-
treta"^, yl. vii, fig. 4c.

Lower Silurian, liussla.

SIPHONOTRKT.V, Vkrnkuil. '

Page no.
SiPHONOTRETA UNGUICULATA, Venieilil.

Fig. 22. Cardinal portion of the pedicle- valve; showing the inner extension of the sipho, which is appar-

rently atrophied and ca;cal.
Fig. 23. A similar portion of another valve in which the sii)ho is Ojien.

(KuTOKGA, (tp. ait., pi. vi, fig. 3, a, b.)
Fig. 24. A portion of the shell near the anterior margin, much enlarged to show the tubular structure, the
epidermal layers and the mode of oi'igin of the hollow .spines.
(KuTORfiA, op lit., pi. vi. fig. 2c.)
Figs. 25, 2G. The interior characters of both valves as given by D.^^vidsom.
(Geological Magazine, 1877, pi. ii, figs. 9, 11.)

SCHIZAMBOX, Walcott.

Page 113.
SCHIZAMBON TYPICALIS, Willcott.

Fig. 27. The interior of a pedicle-valve ; showing an oval foramen with the groove or depressed track, and
diverging lateral muscular ridges. X 5.

Fig. 28. The exterior of a brachial valve; showing the radiating ;inil concentric stri.'e. In this specimen
the snrfai^e appears finely granulose. the gr.anulations jirobably being the lia-ses of minute
spinules like those represented by Mr. Walcoit {Pal.tont. Eureka Dist., pi. i, fig. 3d).

Fig. 29. The interior of a brachial valve ; showing the outline of the muscular area and its subdivision
by diverging ridges. X 5.

Fig 30. Another interior of a brachial valve, ditt'eriiig from the foregoing in the less conspicuous division
of the muscular area. The inner jiair of diverging i-idges terminate anteri(n-ly in deeply col-
ored, oval ai'eas, which are too strongly elevated in the figure. X o.

bowel- portion of the I'ugouip groii|i. Kiirtka District, Nernda.

w 'Ji ^ e :ii:i ^ 3^ © is .a ,

(M^ucric Illustr.itKni'^

Palasont.N Y.Vol PVPt ii= VqI.VHI

Plate IV

e.i.nimoiib.dt!l.

ptul.AsiULi.

PLATE IV— Coutinued.
SCHIZAMBON (?) FISSUS, Kutorgil.

Fig. SI. A pedicle-valve ; showing the external character of the aperture. After Kutoroa, op. cit., pi.
vii. dg. 5a'). X 2.5.

ScHiZAMBON (?) FLSSt;.-;, var. Canadensi.s, Ami.

Fig-. 32. A brachial valve from which the shell is luirtially broken ; showing- the impression of an internal
median septum. All the spines have been removed except those at and near the niarg-ins.
These have been pressed tog-ether in one plane, giving- them the appearance of lieing more
closely set than when standing- at their normal angle upon the surface. X 2.

Fig. 33. The pedicle-valve ; showing the external character of the pedicle-passage. X 2.

Fig. 34. A jiedicle-valve fi-om which most of the shell has been broken, giving a cross-seittion of the

sipho near its imiei' extremity. X 2.
Fig. 33. A brachial valve, the con-elate of fig. 34. The surface retains most of the shell, but the sjunes

are lirokeu, .showing only their bases, except at the mai-gins wliere a portion of their length is

retained. X 2.

Fig, 30. A jiedicIe-valve, so broken as to show the inner edge of the sipho.

All the above specimens are from the horizon of the Utica slate. iVear Gloucester,
Ontario.

SiPHONOTRETA (?) MiNNESOTENSIS, Sp. IIOV.

Fig. 37. View from the brachial side of a sjiecimen retaining- the valves in juxtaposition and preserving
most of the epidermal layer of the shell. The spine-bases about the beak are noticeably large
and more closely set than over the i-est of the surface, where they occur at considerable dis-
tances along the concentric varices. The entire length of the spines is evidently not repre-
sented in the fringe about the margin. X 2.

Fig. 38. The opposite valve of the same specimen. The imperfection of the valve in the umbonal region
has ren<lered it impossible tc5 determine with accuracy the genei-i<- character of the species. X 2.
Trenton Limestone. Minneapolis, Minnesota.

PLATE IV A.

Legend. a. Deltidium. k. Platfoi-m-vaults.

b. Deltidial slope. m. Median scars.

c. Deltidial ridges. q. Crown of the crescent.

d. Areal borders. r. Sides of the crescent,
i. Unibonal chambers. t. Transverse scars.

j. Platform.

TRIMERELLA, Billlng.s.

P.age 33.

Teimerella grandis. Billings.

Fio-. 1. An internal cast, viewed fi-om the brachial side ; showing- the low unilional chambers, the length
of the platform-vaults and the lateral scars of the crescent.

Fi". 2. The reverse of the same specimen; showing the much greater jirominence of the umbonid cham-
bers in this valve. The anterior margin and casts of the vaults have been slightly restoi-ed in
the di-awings.

Niagara group. Near /Sinking Spring, Ohio.

Trimerella Ohioensis, Moek.

Fig. 3. A small pedicle-valve ; showing a di.stortion of the umbo which extends to the posterioi' portion
of the platform. The drawing is made froni n gutta-percha impression, and the shell is some-
what restored in the umb(nial i-egion.

Niagara group. Port Byron, I llinhisi^ ' ,!,';',' -rM-,',V.!

Fig. 4. A brachial valve ; showing the incurvature of the beak, the subumbonal ridge merging into the
crescent, the broad lateral scars of the crescent, the long, relal.i\ely narrow platform with its
medially depressed surface, and the sii-ong .anterioi- septum. Drawn from a gutta-pei'cha
impression of a natural ca.st.

Niagara group. Rising Sun, Ohio.

Fig. ."). Cardinal view of an internal cast of both valves, the pedicle-valve being above. The posterior
margin of the bi'achial valve shows the impres.sion of the umbo and beneath it a deep depi-e.s-
sion representing the crescent ; the deltidial slope of the pedicle-valve is also visible.

Fig. •). Brachial view of the same specimen ; showing tlie dilferent length.s of the (ilatfoi'm- vaults and the
deep umbonal chambers of the opposite valve.
Niagara group. Qenoa. Ohio.

Fig. 7. View from the br.achial side of a specimen retaining the shell ; showing :dso the cardinal aiva
and deltidium of the ojiposite valve.

Fig. S. The deltidium and cardinal area, drawn from a gutta-percha impression taken from the sjiecimen
represented in tigure 9. Slightly enlarged.

Fig. 9. An internal cast of the pedicle-valve of a large indiviiUud.
Niagara group. Ottawa county, Ohio.

Trimerella Dalli, Davidson and King.

Fig. 10. An internal cast of a pedicle-v.alve ; showing the umbonal chamber.?, short jilatform-vaulfs and
inilications of the transverse muscular scars.
Gnelph limestone. New Hope, Ontario.

113 Ifi ^ £ Zii li JD 1? E) LL) ^

Ci I- nf r ir IlUi^ iration;;

Palsont N'

'^tn-VolVm,

PlaieW^

PhilAsili'a.

PLATE IV B.

Legend. a. Deltiilium. k. Platform-vaults.

b. Deltulial slope. in. Median scars.

c. Deltidial ridges. • n. Anteiior scars,
ca. Cardinal area. o. Lateral scars.

ci'. Crescent. q. Ci'owu of crescent.

d. Areal borders. r. Side of crescent.
h. Cardinal buttress. t. Transeverse scars,
i. Umbonal chanil)ers. u. Pallial sinuses.

j. Platform. x. Umbo-lateral scars.

TRlMEKELJvA, BiLi,ix(i,s.

Page 33.

TrIMERELLA LlXDSTRCEJlI, Dull.

Fig. 1. The interioi- of an imperfect pedicle-valve; sliovving- the deep exca\ation at the base of the del-
tidiuni in the place usually occupied by the cardinal buttress.
Aymestry limestone. Island of Gotland.

Trimekella gkandis. liillinojs.

Fig. 2. An internal cast of a portion of a small pedicle-valve.
Fig. 3. The opjiosite side of the same.

Guelph limestone. 6falt, Ontario.
Figs. 4, 5. Transverse sections, showing the structure of the platlbi'ni.

TkIMERELLA ACUMINATA. RillillUS.

Fig. 6. The interior of a pedicle-valve, .'somewhat restoi-ed about the umbo ; showing the platform, lateral
scars of the crescent and the ('xcjivate cardinal buttress. From a gutta-pei'cha impi-ession of
a natural cast.

Niagara limestone. Port Byron, Illinois.

HIIINOBOLUS, H.ALL.

Page 44.

KiiiNDBoLis Gai,ten.-<i.s, Billii)g.s.

Fig. 7. The interior of a pedicle-valve; showing the narrow deltidiimi, Ijroad deUidiai ridges and the
small, imiierfectly developed platform. The drawing is made from a gutta-percha impression
of a mould of the interioi-. the specimen being that originally taken as the type of the genus.
Guelph limestone. Cfalt, Ontario.
Fig. 8. The interior of a small brachial valve.

Guelph limestone. Ekyra, Ontario.
Fig. 9. The interior of a larger brachial valve ; drawn from the specimen figured by Wuiteaves on plate
8, fig. 3, Palseozoic Fossils, vol. iii, pt. 1.

Guelph limestone. Hespeler or Durkajn, Ontario.

Rhinobolus Davidsoni, S,i. IIOV.

Fig. 10. a small pedicle-\alve, showing the internal characters. From a gutta-percha impression of a

natural cast.
Fig. 11. The interior of a brachial valve, believed to belong to the same species.
Fig. 12. The interior of a larger brachial valve ; showing the undeveloped platform, the crescent and the

transverse muscular scars.

Niagara limestone. Gf-rafton, Wisconsin.

PLATK IV B— Coutiiiueil.

DINOBOLUS, Hall.

Page 36.

DiNOBOLUS CONRADI, Hull.

Fig. 13. All internal cast of a bniehial valve, indicating very distinctly the nuisculai- impressions ami tlie
minute platform-vaults.

Niagara limestone. G-rafton, Wisconsin.
Fig. 14. An internal cast of a yovmg pedicle-valve ; showing the close approximation of the platform-viuilts.

Niagara limestone. Near LeClaire, Iowa.
Fig. l.T. An internal cast of a pedicle-valve ; indicating the duplicate platform-vaults.

Niagara limestone. Racine, Wisconsin.
Fig. Iti. An internal cast of a jiedicle-valve in which the vaults of the platform attained nnnsual length.
Fig. 17. The counterpart of the same ; from a gutta-percha impi-ession.

Niagara limestone. Near LeClaire, Iowa,
Fig. 18. A ti'ansverse section of a shell near the anterior edge of the platform.
Fig. lil. An internal ca-st of the pedicle-valve, retaining very distinctly the median and lateral muscular

scars and the impression of the crescent.
Fig. '2,0. The counterpart of the same, from a gutta-percha impression ; showing the usual size and char-
acter of the deltidium.

Niagara limestone. LeClaire, Iowa.
Fig. 21. The interior of a pedicle-valve, having the deltidium extremely developed. From a gutta-percha
impression of a natural cast.

Niagara limestone. Near LeClaire, Iowa.
Fig. 22. An internal cast of a brachial valve, the umbonal cavity of which h;is been filled by thickening of
the shell.

Niagara limestone. LeClaire, Iowa.
Fig. 23. An internal ca.st of a large brachial valve, with the muscnilar impi'essions shai'ply ilefined.

Niagara limestone. Racine, Wi.icoii.sin.
Fig. 24. An internal cast of a brachial valve ; showing the unsymmetrical development of the vaults of
platform, two on one side and three on the other.
Niagara limestone. LeClaire, loica.

m Hi ^ 'iS SI 2 D !P © iiD j;^

( 'I'luMM I lliistiMtion-

N YVol.rV.Ptii'Vol vni

Plate IV B

E.Emmor.s del

Phil-Asilrii.

PLATE IV c.

Legenil. ii. Doltidium.

b. Deltiiiial slope.

c. Deltiiiial ridges,
ca. Cariiiiial iiiea.
eg. Car<liual groove.
CI-. Crescent.

d. Areal hordeivs.

h. Cardinal buttre.ss.
i. Uuiboual ehamber.s.

Fig.

j. Platform.

k. Platform- vaults.

11. Median scai-s.

II. Anterior scars.

o. Lateral scars.

(|. Crown of crescent.

r. Side of crescent.

n. Pallial trunk.';.

i'. Secondary [lallial sinuses.

MONOMERELLA, Billings.

Page 40.

MoNOMERELLA Nevvberryi, HhU iiiid Whittield.

An internal cast of the brachial valve, indicating- a strong crescent ami low nmbonal chambei-s.
The reveree of the same specimen ; showing the short umbonal chainbei's and the deep cardinal

gi'oove.

Niagara limestone. Q-enoa, Ohio.

Fig.
Fig.

Fig.

MONOMERELLA (clif. < JUBICULAUIS, Billillgs).

3. Profile view of an internal cast.

4. Another view of the same specimen ; showing the internal features of the pedicle-valve. The

cardinal groove and the crescent are very conspicuous, the umbonal chambers sliort, scarcely
reaching the hinge, and the lateral muscular impressions very shai'ply developed.
0. The opposite side of the same specimen ; showing the low umbonal chamber, the strong crescent,
and incipient plafform-vaults.

Niiigara limestone. Between &rafUm and Cedarburg, Wlseon.mi.

MONOMERELLA PRISCA, Billillg.S.

Fig. 6. An internal east of a portion of the pedicle- valve, in which the caj-dinal .irea is very high and the
platform slightly unsymmetrical.

Fig. 7. The interior of a pedicle- valve, drawn from a gutta-percha impression of the spei^imen represented

in tig. C, anil slightly restored about the anterior jiortion.
Fig. 8. The intei-ior of a pedicle-valve, in which the deltidiuui is narrow and elevated, the deltidial ridges

obscure, and the .areal borders smooth. From a gutta-percha impression of a natui'al cast.
Fig. 9. An internal cast of a pedicle-valve, in which the umbon.al chambei-s have iheir usual length.

The crescent and lateral scars of the phitform are unusually distinct.
Fig. 10. An internal cast of the pedicle-valve, in which the umbonal chambei-s are of unequal length.
Fig. 11. An intei-nal cast of both valves, to which a jiortion of the mati-ix adheres; showing the thickness

of the shell in the umbonal regions.
Fig. 12. An internal cast of a brachial viilve, with indistinct radiating, probably v.-isciilar furrows in the

anterior region.

Fig. 13. All intei-nal cast of a brachial valve ; showing the characteristic markings of the .shell.
Niagara limestone. Hmothorne, Illinois.

MONOM ERELLA O RTON I

sp. UOV.

Fig. 14. An internal cast of the pedicle-valve, in which all the characters of the shell are very .sharply
defined.

Fig. 15. The counterpart of the same valve, from a gntta-jiercha imi)ression ; showing the broad deltidium
without evidence of subdivision, the conspicuous cardinal slope and groove, the crescent and
platfonn scars and the pallial trunks with their ramifications.
Niagara limestone. liisiny Sun, Ohio.

PLATE IV c— Continued.
MONOMERELLA EgANI, Sp. IIOV.

Fig. 16. A bi-achial valve ; showing the strongly developed cai-dinal area, the narrow crescent and the
platform scars. The umhonal cavity is filled hy a thick deposit of testaceous matter.
Niagara limestone. Grafton, Wincon.siii.

MONOMERELLA OVATA, Viir. LATA, WlliteUVCS.

Fig. 17. The bi-achial side of an internal cast, believed to belong to this variety. The umbonal cavity is
broad but well defined, the i-rescent and platform scars strongly developed. The three diverg-
ing furrows in front of the platform are probably to be regarded as vasculai- markings.

Fig. 18. The opposite side of the same specimen ; showing the very .short umbonal chambers.
Niagara limestone. Haiotlioi-ne, Illinuis.

m -^i js, D -^ -J. I) 3^ n -s) ^1 o

Gi-noi 11 11 1 us

Pala-ont.M YVol IVPt U=Vol Vin,

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PLATE IV D.

Legend. a. Delticiiuin.

b. Delti<lial slope.

cc. Cardinal area.

eg-. Cardinal groove.

cr. Crescent.

d. Areal borders.

i. Umbonal chambers.

j. Platform.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.

Fig

Fit;

ni. Median scars,

n. Antei'ior scars,

o. Lateral scars,

p. Postmedian scars,

q. Crown of crescent,

r. Side of cres(tent.

M. Pallial sinuses or ri

ige.«(!).

Fig.

13.

Fig.

14.

Fig.

1.5.

MONOMERELLA, Billings.

Page 40.

MONOMERKLT.A KiNGI, Sp. UOV.

1. An internal cast of a pedic'.e-valve ; showing the \ery short umbonal chambers and the sharply

defined inuscnlar impressions.
2 The opposite siile of the same specimen ; showing the internal characters of the brachial-valve.
Niagara limestone. HawtJiorne, Illinois.

MONOMERELLA, .sp. ?

;!. The inner side of a specimen retaining the shell, believed to be a brachial valve of some species
of this genus. This specimen is considered by Whitkaves as the pedicle-valve of Rhinoholiut
Galtensis, Billings. Should Mi'. Whiteaves' opinion prove correct, it will probably he neces-
sary to remoN'e Billings' species to some other genus.

4. The exterior of the same specimen.

Guelph limestone. Gait, Ontario.

MONOMERELLA GrEENH, sp. IIOV.

0. An internal cast of a pediole-valve ; showing the extremely small umbonal chambers and the
sharply defined crescent, cai-dinal groove and lateral scars.
Niagara limestone. Orafton, Wisconsin.

0. An interior cast of the brachial valve ; showing a portion of the broail area of contact, the plat-

form scars, with the diverging anteriin- ridges.
Niagara limestone. Rising Sun, Ohio.

1. The iiitei'ior of a brachial vnlve, from a gutta-percha cast of a natural i;npression. The cre.si'entic

fulcrum is exceedingly strong and the platform very obscure.

8. An internal cast of a pedicle-valve ; showing the very broad cardinal margin and its lateral exten-

sion ; also the faint umbonal cavities and the conspicuous cardinal -g-roove and ci'escent.

9. The interior of a brachial valve, with sharply defined terminal scars and anterior ridges. From

a gutta-perch.a cast.

10. An internal cast of a brachial valve ; showing, in the matrix, the impression of the cardinal area.

The pliitl'orm scars are accompanied by scarcely any thickening of the .shell.
Niagara limestone. 6-rafton, Wisconsin.

MONOMERELLA OVATA, Var. LATA, WllitcaveS.

11. The exterior of a pedicle-valve. Fi-om the original specimen figured by Whiteaves (Palaeozoic

Fossils, vol. iii, pt. 1, pi. 2, fig. 2a).

12. A portion of the interior of a pedicle-valve. Prom Whiteaves' oi-iginal (op. cit., pi. 8, fig. 2).

Guelph limestone. Durham, Ontario.

MONOMEKELLA OVATA, WlliteUVeS.

View from the lu-achial side of a fine specimen retaining the valves in conjunction.

Profile of the same. From Whitbave.s' original specimen (op. cit., pi. 8, figs. 1, la).

The interior of a pe<licle-valve ; showing the broad cardinal ai-ea and deltidial slope, the shallow
umlional chambers, the deep cardin.al groove and lateral scars of the crescent, an<l the sligli'ly
elevated anterior edge of the platfoi-m. Fi-om Whiteaves' original specimen {op. cit. pi ■■>,
fig. IK).

Guelph limestone. Durham, Ontario.

113 If3.^Le!iriI©2F ©IDJV.

y.voi.rv.Ptii'Voi.vin.

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Plate IV D

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Phil.Asilnh.

PLATE IV E.

Legend. V. Fonimen. jui. Anterior aililuctor scars,

p. Pedicle-area, v jia. Pusterior atliliictor sears.

g. External pedicle-groove. ' re. Reti'actor scars,

j;'. The corresponding internal oleva- • t. Lateral scar.s.

tion. ar. Anterior muscular ridges.

DISCINI8CA, Dah,.

I'.ige 120.

Dl.-CINISCA LAMELLOSA, Bl()dori[).

Fig. 1. The exterior of a pedicle-valve ; showing the broad, dcprcs.M^l pedicle-area, and the oval, direct

perforation.
Fig. 2. The interior of the same specimen ; showing the characters of the pedicle-area, of which an en-
larged view is given on Plate IV i'.
Recent. Peiii.
Fig. 3. The interior of a brachial valve ; showing the muscular iniiiressions. After Da viu.son. (Trans.
Linn. Soc, Ser. 2, Zool., vol. iv, pi. 2(), tig. 4. 1S88.)

SCHIZOTRETA, Kutorga.

Page l-.'O.

OkBICULOIDKA (ScHIZOTKKTA) OVALIS. .-il). IIOV.

Fig. 4. A pedicle-vidve from which the shell has been partially broken ; showing the short toraininal

groove. X B. .
Fig. 5. Profile view of the same specimen ; showing the convexity of the conjoined valves. X 3.
Trenton limestone. Middleville, iV. T.

ScHIZOTIiETA COMCA, Dwiullt.
Fig. 6. The interior of a brachial valve ; showing its extreme shallowness and also indicatlnij the jiosition
of the anterior addnctor scars. X 2. From the oi-igijial specimen fignred by Dwiciirr (Amer.
Jonrn. Science, vol. xix, pi. xxi, tig. 11. 18S0).
Fig. 7. An impei'fect pedicle-valve; showing the great elevation of the apex and the short foramina!
groove. X 2. From the original specimen, op. cit., tig. ;J.
Trenton limestone. Newhargh, N. Y.
Fig. b. Outline profile of the conjoined valves. After Dwiuht.

ORBICUI.OIDEA (ScHIZOTRETA ?) TENUn.AMEI.LATA, Hall.
Fig. . 9. The exterior of a brachial valve ; showing the elevated somewhat lamellose growth-lines. X 2.

Niagara group. Western New York.
Fig. 10. The exterioi' of a pedi(de-valve.
Fig. 11. Profile of the same. (This is the Piscina clara of Spencer, = D. solifaria, Ringueberg.)

Niagara limestone. Handlton, Ontiirio.

OEBICULOIDEA, UOrbignv.

Page 1-20.

Orbiciloioea la:mellosa, Hall.
Fig. 12. Theexterior of a brachial valve. X 2.

Trenton limestone. Middleinlle. N. Y. ■

Orbiculoiuea discus, Hall.

Fig. \'.i. The interior of a pedicle-valve ; showing the elevatcil and much calloused walls of foiaininal
passage, and the opening at its postei'ior extremity.

Lower Helderberg group. Near Glarksville, N. Y.

OrBICULOIDEA NUMULUS. .sp. IIOV.
Fig. 14. The exterioi' of a pedicle-valve.

Lower Helderberg group (Waterlime). Marshall. N. Y.

Orbiculoiuea media. Hall.

Fig. 1.1. A lirachial \-alve.

Hamilton group. 8eneca county, N. Y.
Fig. 16. A pedicle-valve.

Chemung group. Trmipsburg, N. Y.
Fig. 17. The interior of a pedicle-valve, retaining the shell over the posterior segment only. Imt showing
the elevated pedicle-area and the perforation at its distal extremity.

Hamilton group. Ontario cutmty, N. Y.

PLATE IV E— Continued.

OKBicui-otnEA Raxdalu, Hall.

Fiir. IS. The I'xterioi- of a pecUcle-valve ; showing-, from compression, the apical muscular ridge, the
i-ailiating- pallial sinuses ami the internal track of the pedicle-furrow extending- toward the
margin and interrupting the concentric gi-owth-lines. The ovei-lap]iing marginal portion of the
opposite valve is seen about the postei-ior arc of the circumference. Natui-al size.
Hamilton groaj). Kear ffcltn/idrii, W. Y.

Obiculoidea pulohra, .sp. nov.

Fig. 19. The e.xterior of a ])edicle-valve. X 1-5.
Cuyahoga shale. Bet-ea, Ohio.

Orhiculoidea AIanhattanknsls, Meek uiid Hay den.

Fig. 20. The interior of a pedicle-valve ; showing the character of the pedicle-area, the i-adiating vascular-
lines, and where the shell is broken on the anterior portion, the character of the external
ornamentation and the unusual thickne.ss of the valve.
Coal Measiu-es. Riley county, Kansas.

(EHLERTELI.A, s.-gen. nov.

Page 120.

G^hlertella pleurites. Meek.

Fig. 21. The interior of a pedicle- valve ; showing the elevated jiedicle-ridge and the open, marginal fora-
men. Natural size.
Fig. 22. ProKle of the same, giving the internal elevation of the pedicle-area.

Figs. 2iJ, 24. Brachial valves, differing slightly in outline, and .showing the po.sterior position of the apex.
Waverly group. Newark, Ohio.

LlNDSTRa:MELI,A, s.-oen. nov.

Page 1-20.

Lind8tru-:mella aspidium, sp. nov.

Fig. 25. Abt-a(-hial valve, from which the shell is largely exfoliated, but retaining sufficient to show the dis-
tinct, elevated, concentric ridges characterizing the exteriuil surface. The great lateral ridges
and the fainter median septum are i-eju-esented by furrows. At the posterior extremities of the
former are seen two small subcircular muscular impie.ssions, while the scai-s of the anterior
adductors are strongly developed. Natui-al size.

Fig. 26. The counteri)art of the same ; drawn froni a gutta-percha imju-essiou, showing all the internal
characters in theii- natural relief.

Hamilton group. Ni-ar HiviaiUon, N. Y.

Fig, 27. A natui-al cast of the exterior of a large pedicle-valve believed to belong to this species; showing
the character of the surface ornamentation, and the peculiar undulation of the concentric ridges
on approaching the peilicle-area. The ijedicle-pa-ssage ditt'ers IVom that in the normal mature
Okbicvloidka, in not lieing closed, though its margins ajipear to be in contact. The characters
of this area as represented in the drawing, hiive been slightly restored from other specimens.
Hamilton group. Nfctr Lennardsville, N. Y.

Fig. 28. A small pedicle-valve, with the charactei-istic ornamentation ami sti-ongly developed foraniinal
groove.

Hamilton grouji. Near Darien, N. Y.

RCEMERELLA, s.-gen. nov.

Page VH).

RfEMERELLA GRANDis, Vanii.xeni.

Fig. 2'.l. The exterior of a brachitil valve.

Hamilton limestone. Falls of the Ohio.
Fig :i(i. The interior of a pedicle-valve from which the shell has been partially exfoliate<l, exposing the

matrix and the cast of the external pedicle-groove.
Fig. :!l. The counterpart of the same specimen, from a gutta-percha cast; showing all the essential ex-
tei-rial i-liaractei-s. The extreme depression of the antei-ior poi-tion of the valve and the cor-
resi)on<lingly great elevation of the pedicle-area are features subject to some slight variation
within tiie limits of the species.

Hamilton grou)). C'azenovia, N. Y.

m m ^ (s m 3. m IF m mi ^

i'^oiu^riv llliisti-aticjii;

. N- Y. Vol . rv. Pt ii - Vol vin -

Plate IV E

0

-h-bramoiis ad.

rTJi.ASl.-it-T..

PLATE IV F.

Legend. K. Foi-amen. i t o(<.,.„i , ,»ii e .\

V Pediule-area Lateral walls of Hi.- -roove.

,}/ I^li, M^?'; "■■ Anterior muscular n,|.r,.s.

p'. Areal oa llos.ty ,. Median septum,

g. Base of the externa pedicle-grroove. v. Vascular sinuses.
g'. Base ot the mternal pedicle-groove.

DISCINISCA, D.vM..

Page 1-20.
DlSClNISlC.\ LAMELLOSA, Jilodeiil).
Rg. 1. '^he internal pedn^Ie-area enlarged to three dian.eters from the specimen represented in Plate
IV E, hg. 2. The pedicle-area IS a .somewhat thickened elevation, corres.M n.lin- to the d^.n
depression on the external surlace of the valve. The foramen transects the ar 'a^d re ■ Iv in
between it and the posterior margin is a narrow translucent huiiina, across which tie con c^nHc
ornamentation of the valve doe.s not pass. (-oncenmc

SCHIZOTRETA, Kutorga

^ Page 1-20.

UBICULOIDEA (SCHIZOTRETA?) TENUILAMELL.\TA Hall
Fig. 2. The exterior pedicle-area of a specimen in which the groove is extremely sl.ort X 5
Fig. 3. A similar view of a specimen in which the groove is rel.Htivelv lar-rer, and the ha«^ walk -md
foramen well defaned. X 5. . ^ - ' ><i.., wans .inn

Kg. 4. The corresponding parts in another specimen. X 5.

Fig. 5. The groove of the same ; showing (hat the concentric growth-lines are retained on the broad lat-
Fi.. 'fi Thf ;yf «' ^^'^■'V'^'^ \^"r "^.™'°'.'"^ """fe'h less distinctly delined than in some instances X 1.
Fig. 6. The pedicle-charactei-s ot the interior, drawn from a natural cast of the exterior, in wW h fro „

Ihe oST"" " """■ "" "'"■'"' '^'"'■"^'"" '"" •""'^^'•^•^^^ *" continuity whhthol; of

Niagara limestone. Hamilton, Ontario.

SCHIZOTKETA CONICA, Dwigllt.
Fig. 7. The^external characters of the pedicle-area; from the specimen represented in Plate IV e, fig. 7.

ORBICULOIDEA, D'ORBio.Nr.

Page liO.
. Urbiculoidea PULCHRA, .sp. llov.

Fig. 8. The internal pe,iirle-area The elevated median i-idge corresponding to the base of the external
groove. IS slightly broken, a crack extending to the foramen. About the tnte°l moietv o f
Vi a n,,""^"^"*^""^ 'literal callosities have just be-un to form. X3 ei loi moieij ol

t^g. 9. I he same, in a more advanced .stage of development. The callosities have increased to such a
degree |is to have almost come into contact for the entire le.gth of the area, lea Wnl- the nosi
tion of the internal ridge indicated by the groove between their edges. X 3 ° ''""'

„. Cuyahoga shales. Bma. Ohio,

tig. 10. I he same parts, sti^ll showing a remnant of the groov=e formed by the meeting of the lateral cnl-

losilies; also indicating the position of the fo'aminal openino- X 3
„. ,, ,0 rr.u Cuyahoga shales. Bacon.'iherg, Ohio.

J<igs. 11, 1.. The same features, from individuals in which the lateral callosities have coalesced, leavinu- the
W T. rrJ^'r^l^^^.'' "Pe",' l^"t Otherwise concealing the structure of the area. X 3. ^

=■ ''• ''hig t^ani zz^^::::"^^^"" '^•■^='"^' ^-"^'^-^ = ^•^'^"•-^ ••- ^'-" -'i-" -i-'-- ^-^^

„. .,„ . Cuyahoga shales. Bprea, Ohio.

Fig. 30. An internal cast of a brachi^al valve; showing the impressions of two strong, diverging vascular
sinuses (?) and finer markings about tlie margin. X1.5.
Cuyahoga shales. Ni-wnrk. Ohio.
Mg. i:. A very young pedicle-valve with a length of 2.2.5 mm., having the posterior margins of the
aperture unclased, while the i.edicle-groove has nearlv its entire normal length X 2
Cuyahoga shales. Berea, Ohio. ' 5 ^ •

Orbiculoidea. coinp.iie O. pllchka.

I'lgs. 14, lo, 16 The internal characters of the pedicle-area; showing the envelopment of th,. ri,ige bv the
lateral ciiHosities, m various stages of advancement. X :<•
Waverly group. Meadvilk, Pa.

,,. ,. „,, . OrIUCULOIDEA .MARGI.XAl.IS, Wllil licld.

°' ^'i^' ■"''^™«1 -characters of the pedi.-le-area. The callosities have assumed an irregular, hur l,i-

l.iteially symmetrical form, almost enveloping the pedicle-rid. -e. x 3
Hamilton group, rttimil'ill". TVi.<:. ' "

PLATE IV F— Continued.

Okbiculoidea Xewbekryi, II;ill.

Fig-. IS. The same featui'es; showing- the strnnu- elevation of the jivp» h.u <i,» ^ ^ e „ ■■

;:^;£i^^^=:,"^^^"^ ^'-"ea.^hot.,hX.(;i.:^^->:^ii::'\.!^^/:^^^'^:,:fjtr:^ z

Wavei-ly group. Cuyahoga Fallx, Ohio.
(From the original locality, a ferruginous ban,l about UO feet below the .conglomerate.)

CEHbp:RTELLA s.-gen ^•o^^

Page 120.
U1.HLERTELLA PLEURITES, Mcck.

"■ 1.".™, atat" ''x s' '°""'' """''°°°- '" ""'* "* """ '" *• •"* ■" ■"«»"> *"'l "■• •Pl«.l

Waverly group. Newark, Ohio.

ORBICULOIDEA, D'Orbignv.

Page 1-20.

Okbiculoidea Loden.si.s, Vanu.xein.

Fig. 21. The int^.-nal characters of the pedide-area; indicating the unu.sual brea.Uh au,i depth of the base
^^'yS'-f'-'^^'^'-^'^fiow^^^.r^Uvalh; al,.o the iuter.'uption in the ornamentfon of the shdl
me ap'tur-r X 4 ""'"' ^"'""'"^' ''"''"'""^ ""' '""^ "'' "'""" "*' *"« p.-imUWe margins of
Genesee shale. Lodi, iV. 1'.

Okbiculoidea, .sp. iiidct.

Fig. 22. A natural cast of the interior apical portion of the brachial valve ; showin- the -interior and no^
tenor muscular ridges. X3 .-■"- wino lue .luieiioi ami pos-

Chemung group. Warren. Pa. '• >'

Okbiculoidea nitida, Pliillips.

Fig. 23. The pe,iicle-area of an extremely youug shell, having a diameter of 1 mm. The fc-ameir is a

marginal sht extending, with divergent edges, for almost the entire radius of the valv^ Ki

v:» OA . ">^■•V"^^• '^'; l'^''>i'^le-gr.ove appears in an incipient stage. X SO. =' « tne Nalxe. At

F.g. 2:,. A later stage of growth, exhibited by a .specimen 7 mm. in diameter. Here the andes m-i.le bv

Tj- o„ ,„, . , i^oweiuoai Measures Spruiujitld. IlUvois.

Ftg. 2fa. I he internal pedicle-.urea of a small but mature individual; showing the base and lateral walls

P- 0- -PP."' '^' *f'-»o^-ef 1^' <he slight callosity at the apical extremity. X 7

Fig. 2,. The externa surface of a similar specimen ; showing the general form of the groove at matnritv

Fig. 28. The entire valve of which tig. 27 represents the pedicle-area. X 2
. Coal Measures. G-rovei; Mi.^.wuri.

Okbiculoidea, sp.. Meek.

at iNont: £i '•'■'i'E 1>^1 r; ''"'^T^---' '■•"■•■';-■. with a .-.mall, umnd or ova'l for"

113 3i. J\. S 31 a D 3^ ; cj la ^

( «*'ln'i-u' Illustriiliou-^

Palzeont . N, Y. Vol. IV.Pt ii = VoJ V!!!

Plate !V F

/

(f

L.

^■■rA

•7ifc^

.V^, ^-<,.

i&iir^-^

^r^

11

4

Wf\ I p-

V--~-r- '

u

f%^.

?\-^^

-A.
^1

s. s..ti

r^

ite*«n^^i:^

23

N(

25

:i

-V g

J

S)

32

31

i-Emmons del

Phil.Ast.Uth.

PLATE IVg.

Legend. 15. ]3rii(rliial valve. o. Central scars.

P. Pedicie-valve. [ic. Posterior centrals.

F. Foramen. cc. Median centi-jiis.

p. Pedicle-callosity (in brachial valve). ac. Anterior centials.

g. Pedicle-g-roove. jia. Posterior addiuitors.

g'. Base of groove. jia'. Anterior element of posterior ad-

1. Walls of groove. ductoi'S.

f . Meilian .septnni. aa. Anterior adiliictor.s.

o. Posterior musculiir si'ar.<.

T1;I:MATI8, Sii.vun:.

I'age 13S
TkEMATIS TEKMINALIS, EllimoilS.

Fig. 1. The interior of a brachial valve; .showing the postei-ior and central mnscnlar .-Jcai-s and the lingui-

form median elevation. X 3.
Fig. 2. An internal cast of the pedicle-valve : showing the great depression of the jiedicle-area, the

median ridge corresponding to the pedicle-groove, and the vascular sinnses. X 3.
Trenton limestone. Mkldleritli', JV. Y.

Tke-Matis, sp., ionii)aie T. punctostkiata, Hull.

Fig. 3. The internal pedicle-area ; showing the elevation of the mai-gins of the tissnre. X 4.
Huilson River group. Frankfort, Ky.

TllEMATIS MILLIPUNCTATA, Hall.

Fig. -1. The inteiior of a brachial valve : showing the posterioi' callosity forming a surface iov the pa.s.sage
of the pedi(-le, the external muscular scars and the components of the centra! imjiressions. X 2.
Hudson River gi-oup. Covington, Ky.
Fig. • 5. An intei'nal cast of a brachial valve, to which a portion of the shell adhei-es. X 2.
Fig. 6. The exterior of a brachial valve, from which the shell is partially exfoliated, X 2.
Fig. 7. Pi'ofile of an internal cast of the conjoined valves.

Fig. S. Anteiior view of the same specimen, exposing the pedicle-valve and the iirojectitig apical portion
of the brachial valve. X 2.

Hudson River gi-oup. Cineinnnti, Ohio.
Fig. 0. The interior of a brachial valve ; showing the jiosterior uiiiscular scars beneath the broken pedi-
cle-callosity. X 15.

Hudson Ri\-er group. Frankfort, Ky.
Fig. 10. The external ornamentation. X 25.

Trematis punctostkiata, Hall.
Fig. 11. The exterior of a brachial valve. X 2.
Fig. 12. The intei-ior of a pedicle-valve. X 2.
Fig. 13. The external ornamentation. X 25.

Trenton limestone. Clifton, Tenii.

Trematis fragilis, Uliich.

Fig. 14. A peilicle-valve ; showing the short and nari'ow pedicie-tissnre.
Hudson River group. Bank Lick Creek, Ky.

Trematis Ottawensis,' BilUiig.s.

Fig. 35. External view of a brachial valve. From a gutta-percha cast of the exterior. Natural size.
Pig. IB. The surface ornamentation. X 25.

Trenton horizon. Frankfort, Ky.
Fig. 17. The external pedicle-area, from a specimen )-eferred with dmibl to this specie.s. X 3.

Hudson River gron]i. Cincinnati, Ohio.

Trematis u.mboxata, I'hicli.

Fig. 18. The exteiior of the brachial valve. X 2.

Fig. 19. The same specimen, with the upper portion of the brachial valve removed, exjiosing the flat lower

valve and its peiiicle-tissure. X 2.
From the original .specimen tigui'ed by Ulhich (American Geologist, vol iii. No. 6, p. 378, fig. 8.

1889). Hudson River group. Covinr/ton. Ky.

PLATE IV li— Continueil
Tl!EMATlS OIll.AlA, Ulliill.

Fif,'. 2(1. The hi-acliial vahc, i-i'taiiUTig- a jiortiiiii of the external oniainentation. X 2.
Kroiii a ■rntka-jiei-cha cast of the original six'cimen {itp. cit., tig-. Ifl).
Hiiilscm Rivei- j.'-i-oup. Cincinnati. Ohio.

SCHIZOCRANIA, Hall imkI Whitkieli).

P.ige m:.
ScHIZOCRANL\ (?) IfUDlS, Hull.
Fig-. 21. The exteiioi- of the brachial valve. X 2.

Trenton limestone. Cliftmi, Teim.

Schizocrania filosa. Hull.

Fig-. 22. The extcrioi- of a brachial valve, attached to Strirphomena aUeniafn. X 2.

Hudson River group. Cincinnati , Ohio.
Fig. 23. The exterior of a large brachial valve.
Fig. 24. The pedicle-valve.

Utica .slate. Mohawk Valley, N. K
Fig. 25. A valve of tStrophomena alttrnata, to which five of these shell.« are attached, all of them exposing
the lower valve.
The figure is taken fi-oni the Pala;ontology of Ohio, vol. ii, pi. i. fig. 12, and the mu.scular scars on
the internal cast of the ui)i>er valve, shown in the left of the illustration, remain as there rep-
resented.
Fig. 26. An internal cast of the bi-achial valve ; showing the elongate, converging po.sterioi' scars, separated
into jiostei-ior and anterior elements; al.so a faint median ridge extending forward beyond the
muscular imj)i-essions. X 3.
Fig. 27. The jiedicle-valve seen on the right margin of fig. 2.5; showing the apical pedicle-callosity or
incipient groove. X 2.
Palfeontology of Ohio, vol. ii, pi. i, fig. 15.
Fig. 28. The pedicle-ai-ea viewed fi-om witliin ; showing more accni-ately the chai-acter of the apical cal-
losity, its median ridge and lateral walls indicating homology with the corresponding parts in
the genus Obbicl'loidea X 3.

Huiison River grouii. Cincinuati, Ohio.
Fig. 29. An individual from which the ujiper portion of the brachial valve ha,s been remiive<l, expo.sing all
the internal characters of the pedicle-viilve. X 2.
it will be oKserved that in this figui-e, as well as in figs. 25, 33, 34 and 35, the diametei- of the
lower valve is less than that of the upper, and the former lies above and within the bas(^ of the
latter, the attachment of the .shell being- largely effected by the marginal portions of the larger
valve.

Hudson Rivei- group. Covington. Ky.
Fig. 30. An internal cast of a brachial valve ; .showing the anterior and posterior muscnlai- scars. The
foi-mer impressions are rai-ely discei-nible. X 1.5.
Trenton limestone. Trenton Falls, N. Y.

Schizocrania Schuchekti, sp. iiov.

Fig. 31. A bi-achial valve, retaining a portion of the external ornamentation, but shuwing the posterioi-
mn.sinilar scars. X 3.

Fig. 32. A smaller brachial valve, retaining most of the exterior surfac-e. X 3.

Fig. 33. An individual from which most of the upper valve has been removed, exposing the pedicle-valve.
The features of the pedicle-area are not .so clearly retained iis to allow delineation. X 3.
Hudson River group. Covington, Ky.

Schizocrania (?) Helderberoia, .si), nov.

Fig. 34. The exterior surface of an individual ; showing the pedicle-valve, its coarsely radiate and obscure
concenti-ic striation, and the ovei-la|)|iiTig edges of the finely striated upper valve. The charactei'
of the pedicle-apertuie is not well retained. X 2.

Fig. 35. The internal surface of the pedicle-valve ; showing what appears to be a broad pedicle-fisssure,
and the overlapping margins of the upper valve. X 3.

Lower Heiderberg group. Nrar Clarksvillc, N. V.

m m ^ s mE s :f d io ^

("loiici'ir lUusti-atKJiis

Palaeont.N.r.Vo!.rVPtn = Vol.Vin.

Plate IV.

%,

' ^fefefc.

/■-■■/ -

1

'K-:

E.Eminons de

Phn.AsiJdi.

PLATE TV II.

Legend, pa. Posterior ailciucloi' scars. in, Meiliau imisciihir I'lilfruiii.

aa. Anterior adductor scars. v. Vascular sinuses.

b. Brachial nuiseular .scars.

CRANIA, Eetzius.

Page U5.

CUANIA L.ELIA, Hall.

Fig. 1. Four individuals attached to the pedicle-valve of i^li-ii>/<ir/iyiic/iii.s plan iiinhouiim.
Huilson River grouii. Oxford, Ohio.

CUANIA AOARICINA, .sp. ilov.

Fig. 2. An individual attached to a branch of Tkem.\toi"oua ; showing the characteristic sparse and
relatively coarse radiating ribs. X 3.

Lower Helderberg group. Near Clarksrille. N. 1'.

Crania tulciiella, sp. iiov.

Fig. 3. An individual attached to the valve of Orthis sabcarinata. It difi'ei's from the preceding species
in its tiner, more numerous ribs and greater size. X 2.

Lower Helderberg group. Near Clarksrille, N. V.

Crania Boruexi, ILill mid Wliillicld.

Fig. 4. An individual attached to a valve of Spirifer Owe/ii ; showing the very fine radiating striie, and

the conformation of the upper valve to the surface of attachment.
Fig. 5. Protile of the same specimen.

Hamilton limestone. Clarke county, Indiana

Crania crenistri.vta, Iltill.

Pig. 6. The interior of an upper valve ; showing the strong anterior adductor scai's and vei-y faint poste-
rior adductors. X 2.

Hamilton hmestone. Falls of the Ohio.
Fig. 7. A portion of a cast of the internal surface in a decomposed cliert ; showing the filling of vertical
canals. X 25.

Coi'uiferous limestone. Canandaiyiia, N. 1'.
Fig. 8. The interior of an upper valve ; showing the very strong antei'ior .addnclor scars with mar-
gins elevated, and the more obscure posterior scars. X 3.

Hamilton limestone. Fall.': if the Ohio.
Fig. 9. The exterior of a large uppei- valve. Natural size.

Hamilton group, ('anandaigna Lake, N. Y.
Fig. JO. A smaller uncompressed individual.
Fig. 11. Hi-ofile of the same.

Hamilton grouj). Western New York.
Fig. 12. A valve of the .same, or a closely allied species, attached to Orthlt inqire.-(sa. X ;'i.

Upper Devonian. Rockford, loioa.

Crania Rowleyi, (tuiIcn .
Pig. 13. An individual showing the upper valve. X 2.

Chotean limestone. Pike county, Missouri.

Crania setigera, Hull.

Fig. 14. An individual, referred to this sjiecies with some hesitation ; attached to a bi'anch of Monticdli-
PORA. It will be oliserved that for some distance about the anterior edges of the shell, where
the valve.s Ojiened for the admi.ssion of food-bearing watci-cni-reuts, the outward growth ot
the bryozoan cells ha* been obstructed. X 2.

Trenton horizon Mianiapolis, Minnesota.
Pig. 15. An upper valve. X 2.
Pig. 16. Profile of the same. X 2.

Ti'enton limestone. Mineral Point, Wisconsin.

Crania .-^i'imgera, Hull.

Fig. 17. The original specimen ; an individual attached to the shell of IViyiiehonelta Strirklandi. The
ornamentaliim consists of radiating rows of sharjily defined tubercles. X 3.
Niagara groui> Waldron, Indiana.

ri^ATE IVh— Coiitiiuiei!.

Crania setifera, Hull.

Kijr. 18. A soiiiewliat imperfect upper val\e.

Niag-ai'a group. Waldron, Indiana.

Crania ciranosa, sp. iiov.

Kig-. 19. A soiiitnvliat ili.storted upper valve ; showing tlie liiu-l.\ graimlose surface.
Fig. 20. A portion of the surface enlarged. X 20.

Hamilton group. Centerfield, N. Y.

Crania Tkentonensis. Hall.

Figs. 21, 22. Fi-ont ami protile views of an upper valve.

Trenton limestone. MiddlemUe, N. Y.

Crania scario.sa, Htill.

Fig. 23. A l)ra<-hial valve of Strophumena alteraata, covei-ed with shells of this species all of which can-y
the radiating and fine concenti'ic ornamentation of the host.

Fig. 24. The interior of an upper valve, the external surface of which is overgrown by a Monticulipora.
The posterior adductors are larger than the anterior pair, and near their outer edges the .small
scars of the adjnstors are discernible. In this .species as usually presei-ved the muscular im-
pressions appear as dark discolorations of the shell, indicating a probable greater density of
the shell-substance. X 2.

Fig. 2.'). The interior of a lower valve. The poslerim- scars are more distant and smaller than in the
opposite valve, while the anterior scars are much larger. X 2.

Fig. 26. A shell of PlatyMi-oplua lynx, having the surface of the brachial valve crowded with individuals
of this species.

Hudson Ri\-ei- group. Cincinnati, Ohio.

Crania .multipunctata, Miller (= Crunia scahiosu, Hall).

Fig. 27. One of a group of in<lividnals attached to a fragment of Monticdlipor.\. The punctate surface
charac-ter of the host is impressed upon the shell, gi\-ingit a remote resemblance to the surface
of Tremalis Urminalif:. X 2.

Hudson River group. Covinylon, Ky.
Fig. 28. Another specimen with similar surface mai-kings. X 2.
Hudson Ri\er gi-oup. Blanchester, Ohio.

Crania .-^ocialis, Uliich {== Cranin .fmhioxa, Hall).

Fig. 29. A fi-agment of a crinoid colunm, covered with individuals wdiich retain very liistinctly the impres-
sions of the sutures between the segments. X 3.
Hudson River group. Covington, Ky.

Crania percarinata, Ulficli {== Cru)ii<i seiib/'osa, Hull).

Fig. 30. An individual which has been attached to some species of PtEUROToMARi-i. X 3.
Fig. 31. Another specimen, which al.so bears the surface markings of some gastropod. X 3.
Hudson River group. Covington, Ky.
These figures are from Mr. Ulrtoh's tyjiical .sjiecimens.

Crania, .sp. nov. ?

Fig. 32. The interior of an upper val\e of a probably smooth species. X 2..
Lower Helderlierg group. Near Clarks^nlte, N. Y.

Crania favincoi.a, .sji. nov.

Fig. 33. A lower valve, slightly broken alioat the poslei-ioi- mai-gin, but showing the very large posterior
i.inscular impressions, the deeply impre.ssed anteriors, with sharply elevated margins and
median fulcrum ; also, the radiating pallial .sinu.ses. The shell is attaclied to a .specimen of
F(n'o.^<itts pirwni, Davis.

Hamilton group. Crab Orchard, Ky.

Crania Leoni, Htill.

Fig. 34. The interior of an upper valve ; showing, in addition to the posterior and anterioi' .'idductor scars,

the taint impressions of the lu'achial muscles
Fig. ,35. The exteiior of an upper valve.

Clienumg group. Li'oii, iV. Y.

m m^csisHEiip onD^

rreiienr Illustrations

Paleeont.N YVol,rv.Pt.ii = Vol.VllT.

Plate IV. H.

M

f

tr * 3!

^^j|[|li|li5^

w^.

^^Ik

?6

-vim

^L

E.Emmons del.

I'hil.Ast iith.

PLATE IV I.

Leg'encl. jm. Posteiior acUiuctors.
aa. Anterior ail(iuctoi's.
(111. Dorsal adjustoi-s.
va. Ventral ailju.stors.
mm. Mesenten(^ niiisciilar imiiression.

|i. I'arietal imiii'e.ssion.

m Median impressions.

Ii. Hracliial nni.scnlar im])re.ssion.

V. Va.scular trunks,

v'. Viusciil;ir lirani'lies.

CKANIKLLA, (Ehi.iout.
Craniella Uluichi, sp. IIOV.

Vig. I . A cast ol the interior of a losvei" valve, somewhat restored on ttie rig-ht side ; showing' the strong
antei'i. r and very obscure posterior adductor impressions, and the marks of the vascular sin-
uses. The sliell is convex an<l .shows no evidence of attachment, thougli the external sui'face is
overgrown with a bryozoan. Di'awn from a gutta-percha cast of a natural interior. X 1.5.
Ti-enton limestone. Minneapolis, M'mnesotn.

Fig. 2. The niternal cast of an upper valve, believed to be of the same sjjecies. The sigmoid vascular
impressions ai-e simiilei- tVian elsewhere observed ; the scars of the ilorsal adjustors and of
muscles accessory to the anterior adductors (possibly the brachial muscles) are also apparent.
Drawn from a gutta-percha cast of a natural interioi-. X l.o.
Trenton limestone. MimuapoUs, Minnesota.

CUAXIELLA Hamiltoni.e, Hall.

Fig. 3. The interior of a lower valve attached to a Stkkftei.asim.^ ; showing the usual character of the
muscular scars, viz , anterior and posterior adductors, the venti'al adjustors, and post-median
or mesenteric impression ; also the characteiistic radiating vascular sinu.scs.
Hamilton group. Cimandaigua Lake, N. Y.
4. Tlie interior of an upper valve.

Falls of the Ohio.

Fi'om Pala>ontology of New York, vol. iv, ]il. iii, tig. 23,

Fis

Fig.
Fig.

5.

tj.

Fig.

7.

Fig.

8.

Fig.

9.

Fig.

HI.

Fig.

11.

Fig.
Fig.

12.
13.

Fig.

H.

Fig.

l.-|.

Fig.

k;.

Fi(j

vascular impressions, and very
attachment to an individual of

7(;, Kg. 3. 18(50.

Corniferous limestone.
The interior of an attached valve.

Three indix-idiials of ilift'erent sizes, attached to the sui-face of Tropi/jAih-ptu-s- carlnatus. Opero
citato, pi. iii, tig. 19.

Hamilton group. ]Ve.^tern iVtic Yor/i.
The interior of a lower valve; showing the usual muscular and

great thickening of the shell. X 2.
An upper valve ; showing the modification of the surface from

iSpirifcr audaculii.-:.
Profile view of a normal .shell, attached to Tinpidoleptus carinatus.

Hamilton group. Caiiandoigua Lake. N. Y.
The exterior of an upper valve. From Thirteenth Rept. State Cab. Nat. Hist., p

Hamilton group. We.iteni New York.
Au upper valve, modified by attachment to the post^lateral portion of aright \a.\\f. o( C'ypriciinlcllo
(Microdfin) hellistriala.

Hamilton group. Canaudaiyua Lake, N. Y.
An individual greatly modified by attachment to Tropidoleptun carinatiis.

An internal cast of a large uiijter valve; .showing the usual nuiscular seal's and Ihe pecMiliar
sigmoid vasi'ular trunks with their ramifications.
Hamilton group. Pratt's Falls, N. Y.
An internal cast of a very convex upper valve, greatly modified by attachment. X 2.

Hamilton group. Canandaigna Lake, iV. i'.
Au internal cast of an ujiper valve; showing the characteiistic impressions. X 2.

Hamilton group. Bellona, N. Y.
An internal cast of a convex and apparently free lower valve ; showing the closer apiu'oximation
of the anterior and posterior adductor scars than in the opposite valve, the lieep impresssion of
the mesenteric niu.scle, and the radiating vascular sinuses. The figure is slightly I'estored on
the left side. X 2.

Hamilton group. Center-field, N. Y.

I'lIOLIDOPS, Hall.
Pholidoi'S Tkknionkn.sis, II:i11.

17. A slightly crushed specimen. X 4.

Trenton limestone. MiddleviUe, N. Y.

PhOLIUOI'S ClNCINNATEN'SIS, Ililll.
Fig. 18. The exterim* of a iioi-mal specimen. X 4.

Hudson River gi'ou|i. Ciiicinuali, Ohio.

I'LATE IV I— Continued.
I'HOI.IDOrS SUBTRUXCATA, Hall.
V\g. 19. Tlip extei-ior of an individual; sliowinfr the slightly Hattened iiosterior slope and faint median
ang'uhitiori. X 4.

Hudson River gronp. Lorraine, N. T.

PlIOIJDOP.S OVAI.I.S, Hall.
Fig-. 20. The externa! surface ; showing the characteristic outline and subcentral apex. X 6.
Niagara group. Wald7-ou, Indiana.

PllOLIDOP.'^ .stjUAMlFORMIi;, Hall.
Fi^'. 21. The interior of a large ventral (ij valve ; showing the chai'acter of the muscular area, the median,
anterior ad<iu('tor, loUed posterior adductor, and pai-ietal imjiressions. X 5.
Niagara grouj). Hamilton, Ontario.

Pholidoi'S ovata, Hall.

Fig. 22. An internal cast of a dorsal (!) valve ; showing the sharply defined anterior and posterior ad-
ductors, and the parietal scar. X 6.
Fig. 23. The interior of the oppo.site valve ; showing the relatively small size of the nui.scular area. X H.
Lower Helderberg gi-ouj). Near Clark-niiUe, N. Y.

Pholidoi'S arenaria, Hall.

Fig. 24. An intei-nal <!iust of a dorsal (() valve. Prom the oi-iginal specimen. X 2.
Oriskany sandstone. Knox, N. Y.

Pholidops areolata. Hall.

Fig. 25. An internal cast of the ventral (!) valve. X 3.

Schoharie grit. Near Clarksville, N. Y.
Fig. 26. An internal cast of the opposite valve. X 3.

Schoharie grit. Knox, N. Y.

Phoijdop.s patina, S\). IIOV.

Fig. 27. The extei'ior of a valve ; showing the lamellose growth-lines, ci-ossed l)y fine, interrupted, radiat-
ing sti-iiP. Di-awn from a gutta-percha cast of a natural moidd in ileconiposed chert. X 4.
Fig. 28. The interior of a doi'sal (?) valve. Fi-om a gutta-percha cast. X 4.
Fig. 29. The interior of tlie opposite valve. X 4.

Corniferous limestone. Dt Ceioville, Ontario.

PlIOLIDOP.S CALCEOLA, Sp. llOV.
Fig. 30. The interior of a dorsal (',) valve ; shewing the tei'uiina! beak and snbajiical ai'ea, and the character
of the musculai' impressions. X 12.

Corniferous limestone. Falls of the Ohio.

PHOLinop.s Hamiltoni.k, Hall.

Fig. 31. The exterior of the shell. X 4.

Fig. 32. Profile of the same specimen showing the valves in conjunction. X 4.

Hamilton grou)i. Western New YorJc.
Fig. 33. The interior of a ventral (?) valve ; sliowing the character of the muscular impressions. X S.
Fig. 34. The interior of the opposite valve ; showing the muscular and parietal .scars. X 4.

Hamilton group. Canandaigna Lake, N. Y.

PHOLII)OP8 LINGULOIDES, Hall (?).
Fig. 35. The interior of a dorsal (?) val\e; showing the tei'uiinal and slightly deflected Ijeak, the subapical
area, and the character of the muscular scars. X 2.
Hamilton group. Jiii/htitn Mile Creek, N. Y.

Pholidops oblata, Hall.

Fig. 3(). An internal cast of the dorsal (.') valve, with two deep anterioi- adductoi- sc:ai-s, the posterior ad-
du<:tors lieing very faintly developed, as in the preceding figure. This and figure 35 may
I'cpresent the same species. X 4.

Hamilton group. Oarter'.l MilLs; N. Y.

l^iiOLiDOPR, L'oiiiparc P. Ha.miltonle.

Kisr. 37, The extei'ior of the shell ; showinir the form .■uid nutiiije. X >>■
Ue.lford sli.'.les. linlfin-d. Ohio.

IB m ^^ (s m E m IF \c} m ^

( UMU'l'U I Uusll.lllOU^

Palasont N Y.VolIVPt u-VolVni,

PI

%Hfef:

ijiiiy

A-,. MS

vis-

m

f: ui'

/

M. \ p* P"

/

f\

' ^^gMBV. ..^>^

y

E.Emtnons de!

Phil.AsthtK.

PLATE I\- K.

PA'I'KRULA, Baukandk.

PaRC 78.

Patekii.a (?), .sp.

Fii.'. 1. Th(> interior (if a iiedicli'-valvi', taken from a iiatiu-al cant nf the inlci-iial siii-faiM'. Tin- liniail
marg-inal lionlHr, narrcuv tissurc unil railiate mus<',nlar inai-kiiif;s, in<licato the close agreement
of this fossil with Paterula. X 5.

Quebec group. South St. John'.': Market, Quebec.

M( )NOBOLI N A , Saltei:.

Page S:!.
MONOliOLINA PLUMBEA, Saltcl-.

Fig. 2. Exterior of a brachial (?) valve. X 3.

Fig. 3. Interior of a similar valve. X 3. (Davidson, Brit. Sil. Brach., pi. 1, fiys. 23, 24.)

( )RRr('ULOIl)EA. D'OKmoNY.

Page 12IJ.
( )HI'.ICaLOIDEA, sp. ?

Fig. 4. The interior of a ln-acliial valve ; showing a faint median ajiical septmn and radiating muscular
ridges. X 2.

St. Loui.-< limestone. Crittenden i-ouiity, Ky.

LINGULA, IjKuuuiiiKE.

Pasre 2.
LiNtJULA LINGUATA, sp. IIOV.

Fig. 5. The jiedicle-valve fniui whicli the epidei-mal layer is partially exfoliated ; .showing Ihc peculiar
detiection of the anterior margin, whic'h is a constant featui'e. X 2.
Clinton group. Near Hamiltuii, Ontario.

LlNGliLA, Sli. (?).

Fig. 6. All internal cast to which a fragm(mt of the shell adheres. The surface is covered with minute
papillip, which are probably casts of the inner openings of the vertical canals. X ii.
Black slate (Genesee horizon). Near Vancehurg, Ky.

LiNGULA Wavekliensis, Hciiick.

Fig. 7. View from the pe<licle-valve. of a specimen retaining the impressiim of the pedicle.
Wavei'ly sandstone. Oil City. Peima.

LiNGULA T^ENIOLA, sp. iiov. {==Linyula lamcllulu. Hall, Pal. N. Y., vol. ii, p. 55, pi. xx,

figs. 4 a, b, c. 1S47).

Fig. 8. The jieilicle-valve ; showing the peculiar surface ornamentation, crossed near the beak by (ion-
centric growth-lines. X I.").

Clinton group. Clinton. N. Y.

LiNGULA CUNEATA, ColU-ilt-I.

Fig. 9. An internal cast of a pedicle-valve ; showing the muscular scars and vjuscular sinuses. X 3.
Medina saniistone. Medina, N. Y.

l'I,ATK IV K— Continued.
LiNGULA LAMELLATA, Hall.

l"i}r. 10. View from the pedicle-valve of an intcnial cast, retiiiiiing llie iiuiiivssioii of the lateral and central

muscular scars ami of the jiallial sinuses. Tlie luati-ix i.s tilled with minute ovoid bodies (ova).

which appear to lie distributed wherevei- the siuu.ses and llieir branches have extended. About

the anterior and lateral luargius of the valve the matrix is the opacjue mud of the .sediment ;

elsewhere the spaces between the ova are transluceut. X -i-
I'ig-. II. The opposite side of the .same .specimen ; also showing- the muscidar, vascular and sejilal impres-

sion.s. The intermixture of the opacxuc matrix on this side is somewhat greater than on the

other, obliteratinjj the ova to some extent. X 3.
Fif,'. 12. A thin section of a portion of this specimen, which shows the ovoid bodies to be opacpie and

homo^-enous. X 12
Kijr. i:!. An enlargement of the surface of the cast ; showing the appearance of the ova when magnified 12

diameters. The \-ertical ridges are (•asf.s of radiating furrows on the interior of the valve.
Niagara group. Near Hamilton., Ontario.

LINGULOPS, Hall.

rage IS.
LlNGULOPS GrANTI, Sp. IIOV.

Fig. 14. The inferior of a brachial valve. X t>.

Fig. IT). The interior of a pedicle-valve. The muscular area is here developed into a well-iletiupd plat-
form, while in the other species of the genus, L. WhitfieUli and L. Norwoodi, it still retains its
linguloid character. X 6.

Niagara group. Hamilton, Ontario.

CONOTEETA, Walcott.

Page 104.
CONOTRETA RuSTI, Wtllcolt.

Fig. U). Anterior view of a pedicle-valve. The apical and anterior regions retain a. portion of the shell,

but elsewhere the shell is removed, showing the impressions of the internal radiating mu,scu!a,r

ridges. X 4.
Fig. 17. An intei-nal cast of a smaller j)edicle-valve ; sliowing the iilipression of the strong apical callosity,

and the radiating ridges. X 8.
Fig. 18. An apical view of the .same valve ; showing the subtriangular posterior slo]ie, and its obscui'ely

defined median furi-ow. X 9-
Fig. 10. Cardinal view of a very young individual, in which the po.stei-ior slope is vei-y faint. X 12.

Trenton liiiKwtone. Trenton Fall.t, N. Y.
Fig. 2(1. Cartiinal view of another very small example, retaining the shell.
Fig. 21. Profile of same. X 25

Hudson River group. Cooinyton, Kij.

OBOLUS, EicHWAij).

Page SO.

Obolus [?] PULGHEU, Matlliew.

Fig. 22. The e.\terior of a vaKe, I'etaiuing the shell and showing the character of its ornamentation. X ii.
St. .lohn group. Cato7i'.i Island, New Brun.'iwick.

DISCINA, Lamakck.

P.ige 120.
DbSCINA 8TUIATA, Sclllllliaclll'f.
Fig. 23. The interior of a pedicle-valve.
Fit' 21. The exterior of a similar valve. Mu(-h enlarged.
Recent. Cape Palmas.
(After n.wiDso.v. Trans. Linnean Soc, Ser. 2, Zool., vol. i\-, pi. 2:", tigs. 24, 25. 18S9.)

IS mj^ssiii©:? ibie^

I •cufi u llliislr.ilu.ii

Palasont , N Y.Vol , IV Pt !! - Vol VIII

Plate IV K

<^

E.Emmons de;

PhiLAsilith.

PLATE V.

(Fiirurcs 1-S, 13. 18-2«, iV-JH by E. Emmons; h IJ, H-17, 27, -.'S, ,17-41 by U. 1'. Whitkiki.d.)

Legend. A- Deltidium. a'. I'ostcriur adihictui- impressions,

t. Teeth. r. Anterioi' diductor impressions,

j. Cardinal process. r'. Posterior diductor impressions,

fp. Crural plate. v. Vascular markings,

a. Anterior .'nlductor imjjressions. s'. Deltidial plate or eallosity.

ORTHIS Dalm.\n. 1828.

l':ige 1S6.

Orthls, as lestrictcd.

P.ige 19i.

"OiJTiris ORTHAMBOMTES (Piinder) " Billing.s.*

Fig's. 1, '2. Exterior and intei-ioi' views of a pedicle-vidve. X '■^■
Fig. 3. Interior of a liraidiial valve.

From Ml-. BiLLiNti.s' original specimens. "Point Leuis ; in the uppur part of Limestone No. 2,
Quebec group."

Oktiiis Euryone, Billinsis.

Fig. 4. Extei-ior of a pedicle-valve; from tlie original specimen. " Point Levis ; in the upper part of
Limestone No. 2, Quebec group"

Ortihs David.soni, de Venieiiil.

Fig. 5 Interior of a pedicle-\alve ; sliinving the character of the cardinal and muscular areas.

Fig. 6. Profile of an imlividnal having tlie \ alves in conjunction.

Fig. 7. A portion of the exterior of the pedicle-valve; showing the fine transverse strije and the oiieiiings

of sparsely scattered, oblicjue tubules, which penetrate the outer layers of the shell. X 4.
Fig. 8. A portion of the cardinal area of the brachial valve ; showing the linear cardinal process, crural
plates, thickened deltidi.'il area and the low median ridge. X 3.
Upper Silurian limestone. I.sland tf Gfotland.
For further iUu.stration, see Davidson, Silurian Brachio, oda, plate xxxv, tigs. IS, 19.

Ortiiis tricenaria, Conrad.

Figs. 9-11. Views of the brachial and pedicle-valves and the protile of a specimen with valves conjoined ;

showing the general exterior characters of this type of .structure.
Fig. 12. The interior of a pedicle-valve; showing a slight apical accretion or callosity in the delthyi-ium,
and the muscular ai'ea in wiiich the impression of the central adductors is unusually developed.
Trenton horizon. Mineral Point TViscousin.
Fig. 13. The cardinal area of a pedicle-valv(^ ; showing the character of the apical callosity partially tilling
the delthyrium. X 3.

Trenton horizon. iSt. Paul, Minnesota.
Fig. 14. The interior of a brachial valve ; showing the character of the process, crural jilates and muscu-
lar area.
For further illnstrafion, see Palieontology of New York, Volume I, pl;ite xxxii, fig. 6.

Orthis costalis, Hall.

Fig. 15. An internal cast of the pedicle-valve; showing the characters of the muscular area and vascular

markings. X 2.
Figs. 16, 17. Outline protile and full view of another pedicle-valve.
Chazy limestone. Chazy, N. Y.
For further illustration, see Paleontology of New York, Volume I, plate iv bis, tig. 4.

PLECTORTHIS, nom. nov.

Piige 194.

Orthis plicatella, H;dl.

Fig. 1,S. A view of the brachial valve of a normal adult, a strongly biconvex shell with a moilerately low
cardinal area and strong, distant, simple ribs.

* ^®® "."'S "" "^i* species on page 221. Tlie American shell differs fi'om the Russian 0. calligramma, var. orthambonites,
de verneuil, in its smaller size, fewer an<l coar.ser ribs with line radial striation.s,, iind being thus n quite disiiiict form,
it may receive the designation Orthis Panderiana, nom. nov.

PLATK V— Continued
Vig. 19. The deltulial portion of the pedicle-valve ; showing the liioad delthyrium and the outline of the

musculai- area which is not sufficiently thickened to obscure the plications of the shell. X 3-
V\g. 20. The area in the opposite valve : showing the cardinal process, crural [ilates and low median
ridge. X 3-

Hud.son River gi-oup. Covhii/ton, Kentucky.
For further illustration, see PaL-Eontology of Ohio, Volume I. plate viii, tig. 7.

Orthis dichotoma, Hall.
O. ilirlidtdiiKi, Hall, r= 0. fssicosta. Meek, not Hall.

Fig. '21. The interior of the br;ichial valve ; showing the cardinal process, crural plates and the charactei'
of the plications.

Hudson River group. Covingtm, Kentuvhy.
For further illu.stration, see Palaeontology of Ohio, Volmne I, plate viii, lig. i'>, under the name of
0. jbi.i'i casta.

Orthis Ella, Hull.

Fig. 2'J. An inilividual viewed tVom the lu-achial valve, showing area and foramen of the opposite

valve. X 2.
Fig. 23. A poi'tion of the interior of the pedicle-valve ; showing the characters of the cardinal ai-ea. X 3.
Hudson River group. Covington, Kentucky.
For further illustration, see Palaeontology of Ohio, Volume I, plate viii, fig. 9.

Oiiiiiis K.VXKAKENSIS, McChcsiicy.

Figs. 24, 25. Brachial and jirutile views of a n<irinal individual.

Hudson River group. XViliiihigUm, Ulhiois.

Orthis Whitfieldi, N. U. Wincholl.

Fig, 26. The inteiior of a pedicle-valve ; showing the relatively high area and .strong teeth, the character
of the muscular area, and the low ridges radiating fi'om its anterior margin.
Hudson River group. Kpring Valley, Minne.'^oto.

DINORTPUS, NOM. NOV.

Page. 195.

Orthis pectinella (Einnion.s), Coinad.

Figs. 27, 28. A view of the pedicle-valve, and protile of a .specimen in which the I'ibs are more subdivided
toward the margin than is usual in the species. X 2.
Trenton limestone. Lewis county. New York.
Fig. 29. The interior of a small pedicle-valve; showing the subqiuidrate muscular area with the posterior
.and anterioi' diductor and the .adductor scars.
Trenton horizon. f!t. Paul, Minnesota.
Fig.s. 30, 3L A view from the ]iedicle-valve and the protile of a large individual, sluiwiug the .strongly ele-
vated, siinjile ribs.
Fig. 32. The interior of a pedicle-valve.
Fig. 3'!. The cardinal portion of a brachial valve. X 2.

Ti'enton hoiizon. Curdsville, Kentucky.
For further illustration, .see Palaeontology of New Y(n'k, Volume I, jilate xxxii, tig. ]',

Orthis Sweeneyi, N. H. Wimholl.

Fig. 34. Exterior of the pedicle-valve ; showing the depre.s.scd-convex shell.

Fig. 3."). A jii-fifile of conjoined valves; in this lignre the pedicle-valve as I'epresented is too convex and too

higli at the head.
Fig. 30. The interior of the brachial valve.

Trenton horizon Ht. Paul, Minne.'iota.

ORTHIS as rcsfiictcd.

Page 1U2.

Orthis flabellites, Hall.

Figs. 37, 38, 39. The exterior of the pedicle and brachial valves and profile of an average specimen.
Fig. 40. The interioi- of the pedicle-valve ; showing the character of the uuiscular area.
Fig. 41. The interior of the brachial valve ; showing the cardinal process, crural plates ami cpiadripartite
muscular area.

Niagara group. Lockport, N. Y.
F'or further illustraticm see Palaeontology of New York, VolimK; II, ]ilate lii, figs. 6, 7.

m m j^ (s mE ® IF ©Miix,

0 r I h 1 d ae ^

Palseont.N r Vol rv.Pt,ii = Vol, VIII,

< IM lllu,ll-^.lh

Plate V

%l3i^

E, Emmons del

PhilAsiiitli.

PLATE Va.

(Fijfures 2, 4, IS-Jl, 24-40 liv K. ICmmoxs; 1, :!, 5-14 by K. 1'. WimiiKi.ii ; 1.") I,\ K. U. Mkkk ; iJ Ijv riiiLii- A.si ;

■23 by i. C. McCoxstLL. )

Legend. A- Deltidium. a'. Posterior adductor impressions,

j. Cardinal process. r. Diductor muscular impressions,

fj). Crural plate. p. Pedicle-muscular imjiression.

t. Teeth. o. Ovarian impressions.

1). Sockets. V. Vascular markiuirs.
a. Anterior adductor impressions.

HEBERTELLA, nom. nov.

Page 198.

•Okthis sinuata, Hall.

Fig. 1. The interior of a pedicle-vah-e ; giving the chai'acter of the muscular area, ovarian and vascular

. markings.
Fig. 2. An enlargement of the muscular area of the pedicle-valve ; showing the large diihictor (;•), lineal

central adductor (a) and the pedicle-scar (p). X 2.
Fig. 3. 'I'he inteiioi' of a bi'achial valve.

Fig. 4. The muscular and deltidial area of the brachial valve; showing the iiari'inv, slightly tliickened
cardinal process {j), the large ci'ural plates and the (piadripartite imi>i'ession of the adductor
muscles. X 2.
Fig. 5. The exterior of a brachial valve.
Figs. 6, 7. Cardinal and pi-oiile views of the same specimen.

Fig. 8. Exterior of the pedicle-valve ; the ai'ea and delthyrium of the opposite valve showing.
Hudson River gi-oup. Chicmnati, Ohio.
For further illustration see Pala-ontology of Ohio, Volume I, plate ix, tig. 4.

Orthis sixuata, Hall. (?) (Compare 0. Maria, Billings.)

Fig. 9. A view of the brachial valve and profile of a specimen doubtfully referred to this species.

Hudson River group. , Ofiiu.

Fig. 10 = 19, by error.

Orthis occidextalis, Hall. (?)

Figs, 11, 12. Views of a small specimen with coarse, simple plications, and the median sinus iucipieutly
develojied ; probably the yoimg of this species.

Hudson River group. iSamimah, Illinois.

Orthis insculpta, Hall.

Fig. 13. The interior of a pedicle-valve ; showing the muscular, vascular and ovarian markir.gs. X -•
Hudson River group. Oxford, Ohio.
For further illustration see Palseontology of Ohio, Volume I, plate ix, tig. 1.

PL.ESIOMYS, NOM. NOV.

Page 1(16.

Orthis retrorsa, Stiltei- (= 0. C'arlei/i, Hall).

Fig. 14. The interior of a pecicle-valve ; showing the short dental lamellie, subqnadrate muscular area,

the vascular and ovarian makings.
Fig. 15. A view of the pedicle-valve of the orignal specimen ; showing the high area and retrorse beak of

this valve.
Fig. 16. Profile of a large individual ; showing the gi-eat convexity of the brachial valve and the degree of
resupination of the beak of the pedicle-valve.
Hudson River group. Oxford, Ohio.
For fui'ther iUustratioti, see Palteontology of Ohio, Volume I, plate xi, tig. 7.

Orthis sobquadrata, Hall.

Fig. 17. The intei-ior of the pedicle-valve ; showing the component scai-s of the subcpiadrate muscular are;i,

the lateral ovarian areas and the vascular impressions over the pallial region.
Figs. 18, 19. Brachial and caidinal views of a normal individual.
Hudson River group. Oxford, Ohio.
For further illustration, see Palseontology of Ohio, Vohuue I. plate ix, tig. 2.

Fig.
Fig.

24.

25.

Fife.

26.

Fiff.

27.

I'L.VTE V A— Continued.

Okthis pokcata, McCoy.
Figs. 20, 21. Bi-achial ami profile views of an average example ; showing the rotundity of the brachial valve
and the resupination of the opposite beak.

Mi<l(lle Silurian. Junction Cliff, Anticosti.
For further illustration, see Davidson, Silurian Brachiopoda, plate xxxii, figs. 12-20.

ORTHOSTKOPIIIA, Hall.

Page 199.

Ortiiis Halll Saffbrd (? = 0. slroph&menoides, Hall).

Fig. 22. A view of the pedicle-valve.

Fig. 23. A cardinal view of the conjoined valves of the same specimen.
Lower Helderberg group. Pen-y county, Tennessee.

Orthis strophomenoiues, Hall.

See Plate VI, fig.s. 82-34.

The exterior of a brachial valve.

A cardinal view of the same specimen : showing greater convexity than the preceeding species.

(The relative position of the valves as represented in the figures 23 and 25 is reversed.)
The interior of a lirachial valve ; showing the character of the cai'dinal process, mnsculai- area,

ovarian and vascular markings.
The interior of the opposite valve. The muscular area is greatly thickened and is divisible into

the adductor .and diductor elements; the vascular sinuses are also very distinct.
Lower Helderbei-g group Near Clarhsville, N. Y.
Foi- further illustration, see PaUeontology of New York, Volume III, plate xxiii, fig. 7.

PL^SIOMYS, NOM. NOV.

Page 1915.

Orthis deflecta, Conrad.

Fi"-s. 28, 29. The extei-ior of the brachial and pedicle-valves.

Fi"-. 30. A cardinal view of the .same specimen ; showing the elevation of the area, the convex deltidium,
and the convexity of the bi-achial valve.

Trenton horizon. Dixon, Illinois.
For further illustration, see Palfeontology of New York, Volume I, plate xxxiB, fig. 5.

Orthis loricula, sp. nov.

Fig. 31. The cardinal area of the pedicle-valve ; showing the deltidiinn.

Fig. 32. The exterior of the pedicle-valve.

Fig. 33. The interior of the brachial valve. The delthyrium is tilled by a callosity which also supports

the crnriil plates and the linear cardinal pi-oce.ss ; the deltidinra is also present in an incipient

condition.
Fig. 34. The interioi- of the pedicle-valve ; showing the character of the muscular area, ovarian mai'kings,

etc.

Galena limestone. Fountain, Minne-iota.

Orthis Holstoni, Safford.

Fig. 35. Profile of the ty|ie specimen.

Fig. 3t>. (."ardinal view of the same; showing the wide delthyrium and elevated area of the jiedicle-valve.

Fig. 37. A view of the brachial valve of the same specimen.

Trenton horizon. iVear Knoxville, Ttnnesee.

Orthis Saffordi, sj). nov.

Figs. 38, 39, 40. Thi'ee views of the exterior of a specimen ; showing its general form and the character of
its surface markings.

Trenton horizon. Near Knoxville, Tennessee.

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PLATE Vb.

(Figures 3, t, 8, 15 -.n, 27-3'J, by K. P. WmxriELu; 9, i2--2ii, by E. Liuio-xs; 10-11, by J C. McCo.nnell.)

Legend. A- Deltidium. a. Aiiterioi- aiiiiuctor impressions.

j. Cardinal ijrocess. a'. Posterior adductor impressions,

t. Teeth. r. Anterior diiluctor impressions.

b. Sockets. r'. Posterior didnctor impressions.

c. Crura. o. 0\'arian marking's,
s. Septum. V. Vascular markings,
p. Pedicle muscle.

PLATYSTEOPHIA, King.

Page -100.

OUTHIS BIFORATA, Sclllotlicim, Viir. LYNX, vou Eicliwiilcl.

Fig-. 1. A cardinal view of an average individual ; showiTig the area and deUhyrium of each valve. (The

lines limiting the delthyrium are too strongly defined.)
Fig. 2. An exterior of the brachial valve of a smaller specimen.

Fig. 3. The interior of a brachial valve ; showing the narrow, linear cardinal process, large crural plates

and the quadripartite impi-ession af the adiluctor muscles.
Fig. 4. The interior of a lai-ge pedicle-valve. The apical portion of the shell has been absoi'bed, being

the usual condition in old shells of this form, thus exposing the impression of the pedicle-muscle.

The specimen also shows the compact form of the muscular scars, the vascular trunks and ova-

I'ian markings.

Hudson River group. Cincinnati, Ohio.

Orthis BIFORATA, Sclilotheiiii, v:ir. LATicosTA, Meek.

Figs. 5, 6, 7. Profile, brachial and front views ; showing the high median fold characterizing this form.
Fig. 8. The intei'ior of a brai-hial valve.

Fig. 9. An enlai-gement of the delthyrial portion of the brachial valve. The obsolescent character of
the cardinal process is probably due, in jjart, to reabsorption.
Hudson Rivei' group. Cincinnati, Ohio.

Orthis biforata, Sclilothcim.

Fig. 10. The exterior of the pedicle-valve. The surface is covered with tine granules which, however, are
very i-arely retained (ami almost never visible in ordinary specimens). X 3.
Trenton limestone. Trenton Falls, N. Y.
For further illustration of Plattsthophia, see Davidson, Silurian Brachiopoda, pi. xxxviii, tigs. H-
2.5 ; Palaeontology of Ohio, Volume I, plate x.

BILOBITES, LixNE.

Page 201.

Orthis biloba, Liiine.

Figs. 11, 12, 13, 14. Views; showing the variation in form in this species. Fig. 14 is of the type described
by RiNGDEBERG as 0. acutiloba. X 3.

Niagara group. Lockport, N. Y.

Orthis varica, Conrad.

Figs. 15, 16, 17. Three view^s of the same specimen. X 2.

Fig. 18. The interior of the pedicle-valve ; showing the area, delthyrium, teeth and outline of the muscu-
lar area. X 4.

Fig. 19. The intei-ior of the brachial valve ; showing the cardinal pi-ocess, the great ci'ura, large muscular
area, and the i:)ectinated surfaces of marginal contact. X 5.
Lower Helderberg group. Near Clarksville. N. Y.

PT.ATK V I!— CoiitiliuLMl.

HETEKORTHIS, nom. nov.

Page io-2. .
OuTHis Clytie, Hall.

Fig-. 20. A view iil' thi! briicliial valve of the type-specimen; showing the ai'ea and foramen of the pedicle-

val ve.
Fii'. 21. The interior of a pedicle-valve ; showing; the elong-ate scars of the cai-dinal muscles and the small

adductor impressions.
Fig. 22. The interior of the brachial valve. The cardinal process is simple, but veiy high, and the crui-al

plates are much elevated, terminating abi-uptly. Muscular area small and obscurely (juadri-

pai'tite.
Fig. 23. The articular area of the same valve ; showing the divisions of the muscular area. X 2.
Fig. 24. The surface ornamentation, consisting of a fasciculate grouping of the radiating strise, crossed by

minute concentric lines. X 4.

Trenton horizon. Near Frankfort. Ky.

DALMANELLA, nom. nov.

Page iOS.

Okthis Evadne, Billings.

Fig. 25. A view of the brac-hial valve of the type-specimen ; showing area and foramen of opposite valve.
Fig. 26. The opposite side of the same specimen.

•' Point, Levis ; in the upper part of Limestone No. 2, Quebec group. ^'

Orthis testudinaria, Diilniaii.

Figs. 27, 28, 29. Three views of a small form which may prove to be a jierinanent variety of the species.
Fig. 30. The interior of the pedicle-valve of the same form.
Fig. 31. The intenor of the brachial valve. X 2.

Trenton horizon. Mitieral Point, Wiscoiisln.
Fig. 32. The extei-ior of the pedide-v.alve of a normal individual.
Fig. 33. The exterior of the brachial valve of a somewhat larger specimen.
Fig. 34. A profile of the same.

Fig. 3.5. The interior of a pedicle-valve ; showing the chai-acter of the muscular area.
Fig. 36. The interior of a brachial valve, retaining the articulating apophyses and the subdivision of the

muscidar area.
Fig. 37. The central cardinal portion of a similar valve, enlarged to show with greater distinctness the
sti'ucture of the articulating aparatus.

Hudson River group. Cincinnati, Ohio.
Fig. 38. The interior of a large pedicle-valve.

Ti-enton limestone. Middleinlle, N. Y.
Fig. 39. The interior of a brachial valve. X 2.

Ti-enton limestone. Lowville, N. T.

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PLATE Vc.

(Ficuvesl,2, il-ls, i'l-tl. l)v U. I'. Will n i i.i.r>; I. ."■. W, W-IT, by K. Kmmi>n>, .;, J(i J I, In .1. €. iM(:(;(>N-Ni;i,i..i

Legend. A- Deltidium. !i- Aulerior adductor scais.

t. Teeth. ^'- Postei'ior adductor .scars.

b. Sockets. r. Diductor seal's,
fp. C'l-iiral i^lates. o. Ovarian mai-king^.

j. Cardinal process. v. Vascular markinics.

c. Crura.

DALMANKLLA, nom. no v.

I'ajfC -205.
OuTlIIf* EMACERATA, H;ill.

Figr. 1. The central cardinal ijortinn of the interior of a brachial v.-dvc; showing- the processes and

muscular imprints. X 3.
Fig-. "2. The exterior of a brachial valve.

Hudson River group. C'uicinimti, Ohio.
For further illustration, see Palfeontology of Ohio, Voliuae I, plat(^ viii. Htrs. I. 2.

Okthis jSIeeki, Miller.

Fig. 3. The interior of a brachial valve ; showing the cardinal process, crura and muscular scars. The
apparent impressions in the umbo-lateral regions are due to abnormal thickening of the test.
X 2.

Hudson River group. Spri>i.(f VaUey, Minnesota.

Okthis Stonensis, Saffonl.

Fig. 4. Protile of a specimen w iih valves conjoined. X 2.

Fig. :'). A vie-w of the pedicle-valve of the same .specimen ; showing the alternating, fasciculate character
of the radiating strise. X 2.

Orthis sub;equata. Connid.
Fig. 6. A view of the brachial \-alve ot the original specimen ; showing the area and foramen of the op-
posite valve.
Figs. 7, 8. Profile and cardinal views of the same.
Fig. 9. The articular and muscular area of the lirachial valve. X '^■
Figs. 10, 11. Interiors of the pedicle and brachial valves.

Trenton horizon. Mineral Point, Wisconsin.
For further illustration, see Palseontology of New York, Volume I, plate xxxii. tig. 2.

Orthis peuveta, Coiiftnl.

Fig. 12. View from the brachial valve of the origiiui! specimen.
Figs. 13, 14. Brachial and profile views of a larger individual.

Ti'enton horizon. Mineral Point, Wviconsin.
For further illustration, see Palaeontology of New York, Volume I, plate xxxii, tig. 5.

Orthi.s elegantula. D.iliu:m.

Figs. 15, 16. Opposite sides of the same individual ; showing the form of the species as occnriing at this

locality.
Fig. 17. The interior of a pedicle-valve, somewhat enlarged.
Fig. 18. The interior of a brachial valve ; showing the muscular impressions and articidar processes. X 2.

Niagara group. Waldro7i, Indiana.
Fig. 19. Cardinal view of the centi-al poi-tion of the brachial valve : showing the composition of the cardi-
nal process, the great elevation of the crural plates and crura, and their furrowed or crenulated
outer walls. X 3.

Ujiper Silurian limestone. Island of Gotland.
For further illustration, see Davidson, Silurian Br.achiopoda, pi. xxvii, figs. 1-9 ; H.it,i., Twenty-
eighth Rept. N. Y. State Mus. Nat. Hist., pi. xxi, figs. 11-17.

Fiff.
Fig.

30.
31

Fig.

32,

Fig-.

33.

J'l/ATK Vc— Coiitinueti.

Oiniii.s AHCUARIA, sp. iiov.

(.See Supplement lur ilesci-iption.)
Fiirs. 20, 21. Two views of a siUcified, partially exfoliated shell ; showing' somewhat the contour of 0. de-
gantula, but having a more sti-ongly biconvex form.
Niagara group. Pi^rrji county, Tennessee.

Orthis Wisbyensis, Liiidstrom.

Fig. 22. Profile of the pe(iicle-\alve.
Fig. 23. The interior of the same valve.

Fig. 24. The interior of the brachial valve; showing the cardinal process, crural plates and muscular
scars. X 2.

Upper Siluiian limestone. Islmid of Gotland.

Orthts subcarinata, Hall.

Figs. 25, 26, 27, 28. Views of the extei-ior of a normal individual ; showing its form and contour.
Fig. 29. The interior of a brachial valve.
The interior of a pedicle-valve.

A natural cast of the intei'ior of the bi'achial valve ; showing tlie limits of the muscular area, the
ovarian spaces and the main vascular trunks.

A similar internal cast of the opposite valve, preserving the ramifications of the vasciilar sinuses,

and showing also the ovai'ian spaces and muscular scars.
Posterior view of the cardinal ai'ea of the brachial valve ; showing the subdivision of the cardinal

process and the elevation of the crural jilates.

Lower Helderberg group. Near ClarksvUle, N. Y.
For further illustration, see Palaeontology of New York, Volume III, plate xii, tigs. 7-21.

Orthis perelkgans, Hall.

Fig. 34. The intei-ior of a bi-achial valve ; showing the ilivei-gent ridges extending from the line of separa-
tion between the aiiterioi- and posterior elements of the adductor muscle.
Fig. 35. Posterioi' view of the cardinal area of a brachial valve.

Lower Heldei'berg group. Near Clarksinlle, N. T.
For fui'ther illustration, see Paleontology of New Yoi'k, Volume III, plate xiii, tigs. 4-12.

Orthi.s lenticularis, Vaniixcm [= 0. leiUifnrmi.^, Hull).
(See note on page 224.)
Figs. 36, 37. Two views of a small individual.

Corniferous limestone. LeRoy, N. Y.
Figs. 38, 39, 40. Views of a larger, more liiconvex specimen.

Fig. 41. The intei-ior of a pedicle- valve ; showing the character of the muscular area.
Coi'iiiferous limestone. Caledonia, N. Y.

Ortiils Leonensis, Hall.

Figs. 42, 43. Intei'iors of the brachial and pedicle-valves taken IVom imjn-essions of natural moulds.
Chemung group. Cattaraugus county, N. Y.
For further illustration, see Paleontology of New Yoi-k, V< lume IV, plate viii, figs. 3-8.

OUTHIS SUPERSTES, Sp. IIOV.

(i^ee Supplement for description.)
Fig. 44. Proiilo ; showing the convexity of the shell.
Fig. 45. A view of the same specimen from the brachial valve.

Fig. 46. An internal cast of the pedicle-valve; showing traces of the vascular sinvises.
Fig. 47. The inteiior of the opposite valve ; retaining similar radiating furi'ows about the muscular area.
Chemung group. Howard, N. Y.

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PLATE VI.

(tlgures 1-34, by K. 1'. Whiti'iki.u.)

Legeuil. A. Cardinal area. j). Pedicle-area.

t. Teeth. a. Anterior adiluctoi- .«(;ar.s.

b'. Sockets. a'. Posterior aililuclor scars,

d. Dental lamella. r. Antei'ior liiductor scars.

c. Crura. r'. Posterior diductor scars,

s. Median septum. v. Vascular markings,

j. Cardinal process. o. Ovarian markings.

RHIPIDOMELLA, CEhlekt.

I'age 20S.
OrTHLS HYBRIDA, SoWt'lhy.
Figs. 1, 2, 3. Three views of an average individual of the American foi-m referi'ed to this species.
Fig. 4. The interior of the bracliial valve. The character of the diductor muscular scars is here incor-
rectly representeil, the imjiression being quadripartite and not Habellate.
Fig. 5. The interior of the pedicle-valve; showing the expanded muscular scars.
Niagara group. Lockport, N. Y.
For further illustration, see Davidson, Silurian Brachiopoda, |ilate xxvii. figs. 1-i) ; II.iLL, Palaeon-
tology of New York, Volume II, plate lii, tig. 3 ; Twenty-eighth Rept. N. Y. State Miis. Nat.
Hist., pi. xxi, tigs. 18-25.

Okthis Penelope. Hall.

(See Plate VI A. fig. 10.)

Figs. 6, 7, 8. Three view.s, giving the external characters of a normal mature individual.

Fig. 9. The interior of a l)ra(,'hi.al valve; showing the articulating apparatus. The nuisculai' area is quad-
ripartite rather than fiabellate.

Fig. 10. The interior of a small pedicle-vah'e.

Fig. 11. Similar view of an older shell.

Fig. 12. The interior of a pedicle-valve, which shows the thickening about the mu.scular impressions, ac-
companying senility.

Fig. 13. An enlargement of the surface striiE ; showing the openings of the obli(pie tubules upon the stri:e
and the scattered punctie.

Hamilton group. Western New York.
For further illustration, see Paleontology of New York. Volume IV, plate vi, fig. 2.

Orthis Vanuxejii, Hall.

(See Plate VI A, figs. 7, 8.)
Fig. 14. An enlargement of the surface sti-iae.

Fig. 15. An internal cast of the pedicle-valve ; showing the pedicle-scar and othei' muscular impressions.
Hamilton group. Cumberland, Maryland.
For further illustration, see Palteontology of New Y'ork, Voliune IV, plate vi, fig. 3.

Orthis Leuco,sia, Hall.

(.See Plate VI A, fig. 9.)
Fig. 16. The interior of the pedicle-valve.

Hamilton group. IVe.Hern New York.
For further illustration, see Palteontology of New York, Volume IV, plate vii, fig. 4.

SCHIZOPHORIA. Ki.xG.

I'agr- ill.

Oirrin.s Tioga, HtiU.
Fig. 17. The exterior of a brachial valve.
Fig. 18. An internal east of a pedicle-valve.

Chemung group. Near Eliaira, N. Y.
For further illustration, see Palaeontology of New York, Volume IV, plate viii, figs. 20-29.

PLATE VI— Continuetl.

RHIPIDOMELLA, CEhleut.

rage iUS.

Orthis Oweni. sp. IIOV.
(See Supplemeul I'or tiescriptioii.;
Fig. 19. The exterior of a bi-achial valve.
Figs. 20, 21. Interiors of pedicle and V)i-achial valves, respectively.

" Knobstone gronp" of Owen, ^ age of the Waverly. BiMon-immUl Knuhs, Kentucky.

SCHIZOPHOEIA, King.

P.ige 211.
Okthls C.VniNATA, Hull.

Pig. 22. An internal cast of a pedicle-valve; showing the character of the muscular area, at the antei-ior
margin of which are seen traces of the vascular sinu.ses.
Chemung gi'oui'). JS'ear Painted Post, N. Y.
For fnrtlipr illustration, see Palseontology of New York, Volume IV, jilate viii, figs. 30-32.

Okthis Swallovi, Hall.
Figs. 23, 24. The exterior and infei-ior of the jiedicle-valve.

Burlington limestone. Burlington, Iowa.

Orthis Tulliensis, H;ill.

Figs. 25, 26, 27. Three views of a normal individual ; showing the great convexity of the brachial valve

and the shallow pedicle-valve.
Fig. 28. An internal cast of the brachial valve; showing the (piadrnple muscular impi-es.sion and the prin-
cipal vascular trunks. At y is the tilling of the I'ostral cavity of the opposite valve.
Fig. 29. An internal cast of the pedicle-valve.

TuUy limestone. Keuka Lake, N. Y.
For further illustration, see Palteontology of New York, Volume IV, plate vii, tig. 5.

Orthis propinqua, Hall.

Fig. 30. An internal cast of the brachial valve. The subdivision and the course of the vascular sinuses
are very sharply I'etained.

Coi-niferous limestone. Avon, N. Y.
For further illusti-ation, see Palaeontology of New York, Volume IV, plate v, fig. 3.

Orthis impres.sa, Hall.

(.See Plate VI .\, tigs. 26, 27.)
Fig. 31. An internal cast of the pedicle-valve ; showing the subdivisions of the muscular area, and the un-
usual arrangement of the vascular sinuses.
Chemung gi'oup.
For further illustration of this species, see Palffiontology of N.Y., Volume IV, pi. viii, tigs. 11-19.

ORTHOSTROPHIA, Hall.

Page 199.

Orthis strophomenoides, Hall.

(See Plate Va, tigs. 24-27.)
Fig. 32. The exterior of an imperfect brachial valve.

Fig. 33. An internal ca.st of the pe<licle-valve ; .showing the vei'y small muscular area, the ovarian mark-
ings in the uml)o-lateral regions, and the vascular sinuses over the pallial region.
Fig. 34. An internal cast of the bi-achiai valve, retaining the impression of the simple cai-dinal process, and
showing the four sliarply defined adductor scai-s, the ovarian markings and the ramified vascu-
lar sinuses.

Lower Ilelderberg group. Near Clarksville, N. Y.

Palaeonl.N.Y.VollV,Ptii

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PLATE VI A.

(Figures 7-9, U. l!i-25, 29, 3-2, by K. EMMONS; 1, 2, 13-17, 2«. 27, by G. B. Simpson; 3, 4, 6, by 11. 1>. Whiti'IKLD; 10, :», 31, bj

J. C. McConnell; 5, 2S, by J. M. Clakkh; 12, copy.)

Legend, t. Teeth. ii. Anterior adductor scars,

j. Cardinal proce.ss. a'. Posterior aildiietor scai-s.

b. Sockets. x. Accessoi-y adductor (brachial valve)
fp. Crural plates. r. Diductor scar.

c. Crura. o. Ovarian markings,
dc. Deltidial covering (brachial valve). v. Vascular markings.

p. Pedicle-muscle.

RHIPIDOMELLA, CEhlkut.

Page 203.

Orthis circulus, H:i!l.

Figs. 1, 2. Opposite sides of the original specimen of this species.
Clinton group. Reynalc's Basin, N. T.

Orthis oblata, Hull.
Fig. 3. The interior of a small bi-achial valve.

Fig. 4. The interior of a pedicle-valve of the usual dimensions ; showing the muscular area.
Lovvei- Helderbei-g gi-oup. Near Clarksrille, N. Y.
Foi- further illustration of this species, see Palreontolog.v of New York, Volume III, j)late 10.

Orthis musculosa, Hall.

Fig. 5. The interior of a pedicle-valve ; showing the extravagant develo]iment of the diductor scars, the
narrow adductors and the large irapre-ssion of the pedicle muscle.
Oriskany sandstone. Cumberland, Maryland.
For further illustration, see Palaeontology of New York, Volume III, plate xci, tigs. 1-3.

Orthis peloris, Hall.

Fig. 6. An internal cast of the pedicle-valve. The area covered by the muscular impressions is unusually
restricted though normal for the species.

Schoharie gi'it. Near Clarksvillc, N. Y.
For further illustration, see PalEeontology of New York, Volume IV, plate iv, figs. 1, 8-10.

Orthis Yanuxemi, Hall.

(See Plate VI, figs. 14, 15.;
Fig. 7. The intericn- of a lu-achial valve, retaining with unusual distinctness the four scars of the adductor
muscles. The ridges radiating from the anterior margin of the muscular area, are jirobably
of vascular origin.

Hamilton group. Canandaigna Lake, N. Y.
Fig. 8. An internal cast of the pedicle-valve.

From Drift of the Hamilton grouj). Near Elmira, N. Y.
For further illustration, see Paleontology of New Yoi-k, Volume IV, plate vi, tig. 3.

Orthis Leucosia, Hall.

(See Plate VI, tig. 16.)
Fig. 9. An internal cast of the pedicle-valve, with .strong muscular scars, and showing the pitting of the
ovarian spaces (indicating a premature senile condition 1).

From Drift of the Hamilton group. Near Elmira, N. Y.

Orthis Penelope. Hall.

(See Plate VI, figs. 6-13.)
Fig. 10. An enlargement of the cardinal area of the brachial valve, giving the structure in detail. X 3.
Hamilton group. CanandaAgua Lake, N. Y.

Orthis. sp. ? (coniptirc 0. Ptnielojje).
Fig. 11. A pedicle-valve, from which the shell has partially exfoliated; showing the muscular impressions
on the matrix.

Waverly group. Qranville, Ohio.

Orthis I\Iichei.ixi, L'Eveill6.

Fig. 12. View of the brachial valve of a specimen retaining the spines on a portion of its surface. Copit^d
from Davidson's Monograph of the Cai-boniferous Brachiojioda, pi. xxx, fig. 7.
Carboniferous shales. Gateside, Ayrshire, iSvtitland.
For further illustration, see Davidson, Carboniferous Brachiopoda, plate xxx, figs. 6-12.

Orthis Burlingtonensis, Hall.

Fig. 13. The exterioi- of a pedicle-valve.

This species has been regai-ded by Davidson, Mbbk and some other authors aa identical vith 0.
Michelini, L'Eveille. A comparison of the American foi-m with authentic figures of the Euro-
pean species, shows a degi-ee of diffei-ence inconsistent with the identity claimed.
Burlington limestone Sagenilte, Illinois.
For further illustration, see Geol. of Iowa, Vul. I, part ii, pi. xii, fig. 4 ; and pi. xx of this volume.

I'LATK VlA-Conlinued.

OuTHis Thie.Mii, White.
Fig. 14. The interior of the iieiiicle-valve. X 3.

Fi"-. 15. The interior of a brachial valve which retains the ba,?es of the crura at the extremities of the crural
plates. X H.

Burlington limestone (arenaceous beds). BurVmrjton. Iowa.
The specimen referi-ed to this species, with doubt, in Pala;onlology of New York, Volume IV, p.
&'i, plate viii, tig. 2, is not 0. T/iinnu, and will require a different leference.

Okthi.s ilissouitiENsis,* Swullow.

Fi^s. 16, 17. Interior.s of the brachial and pedicle-valves. The asymmetry of the muscular area is an ac-
cidental inisr('|)resentatinn.

Choteau limestone. Pike amnty, Missouri.

OrTHIS DUBIA, Hall.
Figs. IS, 22. Views of opposite si<tes of the same specimen ; showing the peculiar form of the shell. X 2.

St. Louis gi'oup. Lebanon, Kentiiclty.
Fi". 19. The interior of a pedicle-valve ; showing the large delthyriura and strong teeth with the absence
of a cardinal ai'ea. X 2.
The limitations of the muscular area are shown, but its sub<livisions are not pi'eserved.
St. L(mis group. Lancsville. Iiidiana.
Fig. 20. Intei-ior of the pedicle-valve, retaining moie distinctly the subdivisions of the muscular area. X 2.

Chester limestone. Litclifitld, Kentucky.
Fig. 21. The interior of a brachial valve ; showing the .greatly thickened and elevated hinge-plate bearing
the cardinal process and crural plates. X 2.
St. Louis group. Lanctville, IndiaTia.

SCHIZOPHORIA, King.

Pa2;e 211.

Orthis senectus, sp. nov.
Fig. 23. The exterior of a pedicle- valve ; showing its depression over the pallial region.
Fig. 24. An internal cast of the pedicle-valve ; .showing the diductor and adductor scai-s.
Clinton group. Reynale's Basin, N. Y.

Orthis multistriata, Hall.
Fig. 2.5. An internal cast of the brachial valve of one of the original specimens; showing the subdivision
of the muscular area and the divei-ging vascular sinuses.

Lower Helderberg grou)!. Near Clarksville, iV. T.
For further illustration, see Palseontology of New York, Volume III, plate xv, fig. 2.

Orthis uipressa, Hall.

(See Plate VI, tig. 31.)
Figs. 26, 27. Two internal casts of the brachi.al valve, which ret.ain with unusual distinctness the muscular,
vascular and ovarian markings, and also the iraiiression of the multipartite cardinal process.
Chemung group. LawrencevWe. Pennsyivajiia.
For further illustration, see Paleontology of New York. Volume IV, plate viii, figs. 11-19.

Orthis Iowensis, Hall.

Fig. 29. The interior of a pedicle-valve ; showing the mu.scular ai-ea with a strongly thickened and elevated
centi'al addiictur im|U'ession.

Chemung group, ijjae Creek, Io\Ba.
See Geology of Iowa, Volume I, part ii, plate ii, figs. 4 a-i. 1858.

Orthis Macfarlanii, Meek.f
Fig. 28. The interior of a portion of the brachial valve, retaining at (x) the accessory adductor impressions.

Chemung gi-oup. High Point, N. T.
Fig. 30 Posterior view of a specimen ; showing the great disparity in the convexity of the two valves, the

lower being the brachial valve.
Fig. 31. Profile of another individual ; showing the gibbosity of the bi'achial valve.

Chemung group. Howard, N. Y.
Fig. 32. An internal cast of a large brachial valve in which the muscular impressions are unsymmetrically
developed The cast of the cardinal [irocess shows its subdivision on the po.sterior face.
Chemung grou|>. Hir//i Point, N. Y.
Compare figures iia-k, Orthis Tallimisis, PaUeontology of New York, Volume IV, plate 7.

Tlii.s name was preoccupied b,v Orthis Missouriensis, Sluunard ; Reports 1 and II of the Geological Survey of Missouri,

law

rcstv

• Tlii.s name was preoccupied b,v Orthis Missouriensis, Sliumard ; Reports 1 and II of the Geological Survey of Missouri,
, part ii, pajre 20.i, plate C, Bgs. 9 a, b. That species, if belonpinp to tlie ORTHWJi, should be placed under Orthis as
ricted, or under Uixoktuis, thus leavins Orthis Missouriensis of Swallow under the genus Khipodomelh
t The species of OitTUIS= ScHizoiMIoiiiA, de.scribcd as O propinqua, O Tnlliensis, O ivipressa. 0 Iowensis and
0. Macfarlanii, present so many features in common that farlhcr stutl\- aLid conip.irison should be Riven them to determine
the actual value of the characters on which the specific distinction has been bjised, and whether these differences coincide
with their geological relations.

Palaeont. N Y.Vol.IYPt ii-Vol vm.

33 m^CgmSdllF (DIB.^
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PM-Asilidi.

PLATE VII.

(Figures 1-24, -29-32 by R. P. Wuitfield; 33-85 by F. B. Meek; 25-28 copies.)

Legem!. A.. Canlinal area.

DA. Oaiiiiiii'l area, brachial valve.
VA. Cardinal area, pedicle-valve.
F. Foramen.

D. Deliidium. pedicle-valve.
A. Dflthyiiuni, pedicle-valve.
C. Delti iium, brachial valve,
t Teeth.

d. De.ual lamella;,
b. Dental sockets.

j. Cardinal process,

c. Criu'a.

s. Septum.

X. Umbonal vault,

y. Cast of umljonal vault.

p. Pedicle muscular scar,

a. Anterior adductors,

a'. Posterior adductors.

r. Diductors.

lilllPIDOMELLA, CEhlert.

I'age 208.
(.See Plates VI, VIa.)
Ortuis Pecosi, Marcoii.
Vig. 1. An entire specimen viewed from the brachial valve. X 2.
Fig. 2. Profile of the same. X 2.

Fig. 3. The interior of the pe<licle-valve ; showing the narrow cardinal area and the characteristic mus-
cular scars. X 2.
Fig. 4. An enlargement of the surface ; showing the openings of the oblique tubules and minute punctae.
Coal Measui-es. Near Springfield, Illiiuns.

Fig.
Fig.
Fig.

5.
6.
7.

Fig.

8.

Fig.

9.

Fig. 10.

Orthls Penniana, Uerl)y.

View from the pedicle-valve.

Pi-ofile of the same specimen.

The interior of the pedicle-valve ; showing the nearly obsolete cardinal area and the strong mus-
cular impi'essions, especially that of the pedicle-scar.

The interior of an imperfect brachial valve ,- showing the cardinal process, crui'al bases and mns-
culai" impressions.

The cardinal portion of the same specimen, enlarged to show the low, thick ('ardinal process, the
vei'y prominent crura and the quadripartite chai'actei' of the adductoj' area. X 3.

An enlai'gement of the external surface ; showing strong punctation.
Coal Measures. Itaituba, Brazil.

OKTIIOTICHIA, NOM. propos.

Page -213.
OrTHIS (?) MORGANIANA, Dorbv.

Figs. 11, 12. Interiors of iraiierfect brachial valves ; showing the cardinal process, the greatly elevated and
curved crura supported by septal plates which are produced about the sides of the mu.scular
area. In tig. 12 ai'e also seen the accessory adductor scars described by Dr. Derby.

Fig. 13. Section in pi'otile of tig. 12 ; showing the extent of the crural plates and the elevation of the crura.

Fig. 14. The interior of a pedicle-valve, retaining the long dental lamellEe and the median septum.

Fig. 15. A slightly oblique view of another interior of this valve ; showing more distinctly the elevation of
the teeth and the' outline of the muscular area.
Coal Measures. Itaituba, Brazil.

Genus BILLINGSELLA, ren. xov.

P.ige 230.
(See Plate VIU, figs. 7-9.)

BiLLINGSELLA PePINA, Hall.

Fig. 16. The exterior of a brachial valve ; drawn from a gutta-percha impression of a natural mould.
Fig. 17. A natural cast of the interior of the brachial valve.

Fig. 18. The extei'ior of the pedicle-valve. .

Fig. 19. A natural cast of a pedicle-valve ; showing the high cardinal .area, the convex delfidium, the fill-
ing of the rostral cavity and the vascular sinuses in the pallial region.
Potsdam sandstone. Lake Pepin, Wisconsin.

PLATE VII— Continued.

Genus HEMIPRONITES, Pandek.

Page 238.

Hemipronite.s, .sp. ?

Fi^. '20. A view of the i)e(iicle-valve, the cardinal area beiiifj in the plane of vision. The area of the o|)-

posite valve and the deltidia of both valve.s are shown. X 2.
FifT. 21. A cardinal view of the same .sjiecinien ; showing' the characteristic contour upon which is liased

the sepai-alion of these forms from Clitambonites. X 2.

Fiff. 22. A sjiecimen cut horizontally across the unibonal region of the j)edicle-valve ; showing the united
dental lamellse supported by a median septum. X 2.
Lower Silurian. Mujfsia.

Gends clitambonites, Pander

Page 233.

Clitambonites adscendens, Pander.

Fig. 2cf. A cardinal view, giving the subpyramidal contour characterizing this genus; showing also the
foramen in the deltidium. X 2.

Fig. 24. A pedicle-valve with the apex cut away; showing the peculiar internal sti'ucture of this valve. X 2.
Lower Silui'ian. liiissia.

For fni'ther ilhisti'ation, see Pander, Beitrage zur Geogn. russ. Reiches, j)lates xvii, xviii, and de
Verneuil, Geologie de la Russie et des Mont, de I'Oural, plate xii, tig. 3.

Clitambonites (Outhisina) anomala, Schlotheiiii.

Fig. 25. A view of the pedicle-valve ; showing the great retrorsion of tlie apex, the liigh cardinal area of
the pedicle-valve, and the perfoi-ated <;eltidium ; and also the ai-ea and deltidium of the oppo-
site valve. (After de Verneuil, Geol. Russ. et des Mont, de I'Oural, plate xii, tig. 2b.}

Fig. 26. The interior of the brachial valve ; showing the extreme development of the cardinal ai'ea and
deltidium, the latter entirely obscuring the cardinal process; the character of the muscular
and vascular scar.« is also distinctly seen. (After Davidson.)

Fig. 27. The interior of a pedicle-valve. (After Davidson.)

For further illusti-ation, see de Verneoil, Geol. Russ. et des Mont, de I'Oui'al, plate xii, tig. 2.

Clitambonites plana, Paiidei-.

Fig. 28. The interior of the pedicle-valve ; showing the radiating ridges beneath the spondylium. (After
Davidson, Introd. Foss. Brach., plate viii, fig. 158.)

Genus SCENIDIUM, Hall.

(See Plate VIL\.)
P.igeiU,

Scenidium pyramidale, Hall.

(See Plate VIlA, figs. 29, 30.)
Fig. 29. View of the type-.specimeu ; showing the open delthyrium in each v'alve. X 2.
Fig. 30. A cardinal view; showing the size of the areas of the two valves and character of the delthvi-ium.
X2. •*

Niagara group. Liickport, N. Y.

Scenidium insiune, Hail.

Fig. 31. A view of the brachial valve ; showing the concave plate (d) in the delthyrium of the pedicle-
valve. X 8.

Fig. 32. The ojiposite side of the same specimen, pedicle-valve. X S.

Fig. 33. A cardinal view of conjoined valves ; showing the concave plate in the delthyrium (d), the hinge-
pl.ate (a) and the medi.in septum (s). X 8.

Fig. 34. The intiuior of the brachial valve ; showing the elevated hinge-plate and the pi-ominent median

.septum. X 8.
Fig. 35. The interior of a pedicle-valve with an open delthyrium. X 8.
Lower Helderberg group. Near Clarksville, N. Y.

Hi ^X £ Ili "i D If JD XI ^1

Palaeonl. HYVol V,Pt h

Ciein.Tic II1h>jIi-:iI lolis

Plate H

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P ^ A I

'Ji^:: a

Mm.

w-

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X C B2 D

A 1^ D

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31

I

PLATE VII A.

(Figures 1-12, H-2I,'25, 28-31,33-1.!, 11, 46, 48-53 by E. Emmons; 2C, 27. 32 by J. M. Ci.auke; 45 by G. B. Simpson; 47 bv R. P.

Whitfield; 13, 22-24. 43 copies.)

Legend. D. Deltidium. s. Meiiian septum.

j. Caiilinal process. s'. Lateral septum,

t. Teeth. s". Accessory lateral septum.
1. Spoiulylium. a. Anterior adductor impi-essions.

fji. Crural plates. a'. Posteiior adductor impressions.
c. Crura.

Genus BILLTNGSELLA, oex. .nov.

rage >,iO

Okthis (BiLLiNG.sELLA ??) Laurentina. Billing.-*.

Fig. 1. View of the lu-achial valve ; showing the simple plications, area and deltidium of the opposite
valve.

Fig. 2. Profile of the same specimen.

Fig. 'A. The interior of the pedicle-valve ; showing the cai-dinal area, teeth and covered delthyrium ; the
outline of the mu.?cular area and the median ridge.

Fig. 4. The interior of the bi'achial valve, retaining the simple I'ardinal process and the crural plates.

Fig. 5. The central cardinal portion of both valves, enlarged to show the character of the deltidia. On
the brachial valve the deltidium is incomplete, the lateral [lorlions not having united, and thus
exposing the postexior edge of the cardinal process. X 3.

Fig. 6. The .same jiarts in another specimen in which the deltidium of the brachial valve is nearlv com-
plete. X 3.

Anticosti group. Anticostl.

BlLUNtiSELLA PePIiNA, HuU.
Fig. 7. An internal cast of the jiedicle-valve. X 3.
Fig. 8. The interioi' of the same valve, from a gutta-percha iiniiression of a natural mould ; showing the

broad cardinal area, the convex deltidium, teeth, outline of the musculai- area and a single paii-

of vascular trunks. X 3.
Fig. 9. The interior of a brachial valve ; showing the minute, linear cardinal process, and the small,

slightly divergent crural plates. X 3.

Potsdam sandstone. Lake Pepin, Wiscotisin.
For furtheiMllusti-ation of the species, see Report of the Geological Survey of Wisconsin, Volume
IV, plate i, figures 4, 5. For illustration of OrthUina orientalis, a congeneric form, see Bidle-
tin Am. Mus. Nat. Hist., Volume I, No. 5, p. 144. jilate xiv, fig. 6.

Orthis (??) Mycale, Billings.

Fig. 10. The exterior of a brachial valve, tVora the original specimen.

Fig. 11. The interior of the same specimen, enlarged; .showing the quadripartite muscular imjirint .and
the crural plates. Theie is no evidence of a cai-dinal process in the delthyrium. X 2.

"Point Levis; in the uijper part of Limestone No. 2, Quebec group." (Billings.)

Orthis (??) Tritonia, Billings.

Fig. 12. The central poi-tion of the interior of a bi-achial valve, eidarged. Here, as in the preceding spe-
cies, there is no trace of a caniinal pi'oce.ss, though the quadruple division of the muscular
imprint indicates that this is the brachial and not the pedicle-valve. From one of the oi-iginal
specimens. X 3.

Fig. 13. The exterior of the brachial valve. (After Billinus.)

" Point Lici.s ; in the upper part of Lime.itone No. 2, Quebec group." (B\\,usqs.)

GexNus PKOTORTIIIS, gen. nov.

I';i^'e231

Pkotortiii.'* BiLLiNosi, Haitt.
Fig. 14. The exterior of a pedicle-valve. X 2.
Fig. 15. The interioi' of a bracliial valve. X 2.

Fig. 16. The exterior of a small pedicle-\"a!ve ; showing the concave plate or spondy Hum which closes the
delthyrium below. X 3.

PLATE VII A— Continueil-
Fig. 17. A caiilinal viow of the same specimen. X 3.
Fig. 18. All enlarfjoment, of the surface of an internal cast. The granules may be casts of i>inK-tae on the

inner layer of the shell. X 0.
Fiu-. 19. An enlargement of the external surface of the shell ; showing the sharp concentric striie crossing

the alternating plications. X 6.
Fig. 20. The central cardinal portion of the brachial valve ; showing the broad, incurved delthyrium Vi^ith
a thickene<l area at its liase, and the absence of a cardinal process. X ti.
St. John group. St. John, N. B.

Pkotorthis Quacoensis, Matthew.

Fig. 21. The interior of a pedicle-valve. X 2.

St. John group. Portland. N. B.
For other illustration, see Trans. Royal Society of Canada, Sec. IV, 1885, plate v, figs. 20 a-c.

Genus ORTHIDIUM, gen. nov.

Page 241.

Orthidium gemmicula, Billings.
Figs. 22, 23, 24. Three views of this shell. (After Billings.)

Fig. 25. The interior of a brachial valve ; showing the simple, erect cardinal process, coalesced with the
crural plates. X 4.

" Point LM.s ; in the upper part of the Limestone No. 2, Quebec group." (Billings.)

Sub-genus POLYTGECHIA, sub-gen. nov.

Page 239.

Clitambonites (Polytcechia) apicalis, Whittiekl.

Fig. 26. The cardinal portion of the pedicle-valve. The deltidium has been i-emoved exposing the con-
cave spondylium (1) supported l)y a median septum (s) and lateral sejita (s'). The accessory
lateral ridges (s") are al.so seen. X 3.

Fig. 27. The cardinal portion of the lirachial valve ; showing in profile the lateral portions of the deltidium
partially enclosing the simjile cardinal pi-ocess. The crui'al plates are very divergent and
nearly parallel to the hinge-line. X 3. .^

Figs. 28, 29, 30. Three views of the original specimen of the .species, the last showing the high cardinal
area and convex deltidium. X 3.

Calciferous beds. Fort Cassin, Vermont.
For other illustration, see Bull. American Mus. iN'at. Hist., Vol. I, plate xxiv, figs. 1-5.

Genus SCENIDIUM, Hall.

(See Plate VII. tigs. 29-35.
Page 241.

Ortiiis (ScENiDiuM ??) Merope, BiUillgS.
Fig. 31. A view from the brachial valve ; showing the area and foramen of the opposite valve. X 4.
Fig. 32. The interior of the bra<;hial \-alve ; showing the simple cardinal process and the crural plates.
The (ieltidial cavity is thickened transversely, .and ti-om its center a low median ridge extends
forward. X 4.

Hudson River group. Cincinnati. Ohio.

SCENIDIU.M IIaI.LI, Sllffdld.
Fig. 33. The exterior of the pedicle-valve ; showing the elevation of the beak. X 4.
Fig. 34. A cardinal view of the same specimen ; showing the area and open delthyrium on both valves,

with the slender process in the bottom of the brachial delthyi-ium. X 4.
Fig. 35. The exterior of the i)rachial valve of the same specimen. X 4.

Fig. 36. The interior of a l)rachial valve ; showing the triangular hinge-plate I'esting on the bottom of the
valve, and thi; low median septum extending beyond the middle of the shell.
The outline of the valve is more elongate than in the preceding sijecimen. X 4.

Trenton limestone. (" Glade Limestone " of Safford.) Nashville, Tennessee.

113 m. ^ '^ m :l B IT © mj ^

0 r l h : d £& .

Palseont N YVoI IVPt i1 = Vol Vm.

('ot\oric IlhistratKMis

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|i)>!ii ill'

fji

m

jii

iiiiiiiii

^

HP

i

Plate VE A

E.Emmons ael.

Phil.Astlidi.

I'LATE VllA— CoutiiuiUil.

ScENiDiUM Halli, SaH'onl, vakiety.

Figs. 37, 38, 39. Three views of a specimen ; showing the great length of the hinge, the reliitively low and
narrow cardinal areas and the somewhat coarser iilications of the surface. X 0.
Trenton horizon. Camwn Falls, Minnesota.

SCENIDIUM PVUAMIDALK, ll.lll.

(See Plate VII, Hgs. 29, 30.)
Fig. 40. A view of the pedicle-valve ; showing its elev.ition and the character of the surface plications. X •').
Fig. 41. A cardinal view of the same specimen ; showing the concave delthyrial plate or spondylium. X •'>.
Fig. 42. A brachial valve of the same spe<-imen. X ^^
Niagara group. Lockport, N. Y.

SCENIDIUM AREOLA, Queilslcdl.

Fig. 43. A longitudinal section of the two valves ; showing the extension of the median plate into the cavity
of the pedicle-valve. (After Davidson.)
See for further information, Zeitschr. der deutsch. geolog. Gesellsch., vol. xxiii, plate viii ; and
Davidson, Devonian Brachiopoda, Suppl., plate iii, fig.s. 11-14.

Genus ENTELKTES, Fishek de VValdheim.

Page 2U.

Enteletes hemiplicata, Hall.

Fig. 44. An exterior view of a young individual in which the radial plications are rudimentai-y.

Fig. 4,1. A similar view of a small example which bears a plication in the median sinus of the jiedicle-

valve, with a corresponding furrow on the fold of the opposite valve.
Upper Coal Measures, Kansas City, Missoari.
Fig. 46. A similar view of a mature inilividual ; showing the usual character of the surface.

Upper Coal Measures. IVintei-sel, Iowa.
Fig. 47. A cai'dinal view of an individual ; showing the areii and delthyriinn of the pedicle-valve and the

relative convexity of the two valves.
Fig. 48. A profile of a very gibbous old indivi<lual.

Upper Coal Measures. Kansas City, Miisoiiri.
Fig. 49. A pi'ofile of the rostral portion of a pedicle- v.alve ; showing the great elevation of the median and

lateral septa, the edges of which .are more or less broken. X 3.
Fig. .'JO. A front view of the same specimen ; showing the position of the septa, of which the two outer

ones limit tlie area of muscular insertion. X 3.
Fig, 51, The interior of the rostral [lortion of two valves in articulation. The median septum of the upper

or pedicle-valve is liroken otf, but the latei'al septa are retained. In the br.achial valve are seen

the high crural plates whi('h are produced into strongly recurved ci'ura. At ( j) is the small,

lobate cardinal process, and in the Inittom of the valve a low median ridge, X 2.
Fig. 52. A profile of the same specimen ; showing the articulation of the valves and elevation of the crura,

X 2.

Upper Coal Measures. Wiiitersct. loiea.

Enteletes Lamaucki, Fisclicr de W'alilliciin,

Fig, 53. A cardinal view of an individual ; .showing the area and dellhyrium of the pedicle-valve.
Fig. 54. An enlargement of the fine strife of the surface, which are shown to be tubular, as in Rhipidomella
and ScHizopHORiA.

Upper Carboniferous limestone. MJaXsclikowa. Russia.
For further illustration of this genus, .see Waaoen, Salt-Range Fo.ssils, vol, i, pt. 4 ; also. Meek,
U. S. Geological Survey, Final Report on Nebraska, pp. 177, 178, plates vi and viii.

PLATE VIII.

(Figures 1-18, .!'2-31 by R. P. Whitfield; 20, 21 by F. J. Swinton; 19 by G. B. Simpson.)

Legemi. D. Delticiimii, iieilicle-valve. b. Dental sockets.

C. Delti<liiim, l)r:u'hial v.alve. t. Teeth.

A. Delthyriuni. j. Cardinal process.

K. Foramen. a. Adductor scars.

F'. Groove on deliliyriiim. I)r;ichial valve. r. Anterior diductor scars.

A. Cardinal area ; v'. Posterior diductor scars.
a. Inner jiortion.
a'. Outer portion.

Genus RAFINESQUINA, gkn. nov.

(See Plate VIII, figs. 1-11 ; Plate IXa, figs. ], 2. 4 ; and Plate XVa, tigs. 37-89.)

Page 281.

Rafinesquina incrassata, Saflbid* (not Iliill).

Fig. 1. A view of the brachial valve of a large iridividual ; showing the area and open delthyrinm of the
pedicle-valve.

Fig. 2. The interior of the bi-achial valve ; showing the sti-ucture of the articulating apparatus and the

muscular impi'essions.
Fig. 3. A postei-ior view of the same specimen ; showing tlie bifurcate, incisor-sliapeil cardinal process,

its surface sloping backwai-d to the hinge-line, and partially covered by the deltidium. X 3.
Fig. 4. A cardinal view of a portion of the hinge and area ; showing the deltidia of both valves, that of

the pedicle-valve having its surface distinctly grooved. X 3.
Fig. .'). The internal cast of a pedicle-valve ; showing the great size of the diductor scars, and the filling

of the foramen.

Trenton horizon. Platttrdle, Wiscov^nn.

Rafinesquina altehna'I'a, Convad.

Figs. 6, 7. Two views of a .specimen i)resenting normal extei'ual ehai'acters.

Fig. 8. An enlargement of a jiortion of the hinge-area; showing the deltidia of both valves, and the re-
tention of the foramen at matui-ity. X 3.

Fig 'i*. The interior of a brachial valve ; showing the structure of the cardinal process and the adductor
scars.

Fig. 10. The interior of a pedicle-valve; showing the flabellate diductor and the narrow adductor scars.

Fig. 11. A posterior view of the articulating apparatus of the brachial valve. The incisor-shaped branches
of the cardinal jii'ocess are widely di\-ei-gent, and at the bottom of the bifurcation lies a nai'row
callo.sity. The deltidium is well developed but not gi-ooved in the middle, and the dental
sockets are deeply marked. X 3.

Hudson River gi-oup. Cincinnati, Ohio.

For other illustrations, see Palasontology of Ohio, Vol. I, plate vii. figs. 1-3 ; and Palaeontology of
New York, Vol. I, plates xxxi and xxxi a.

Genus LEPT^NA, Dalman.

Page 27().

Lei't^.xa tenuistriata S()woil)y (= L. rlioinJtoidalis, VVilckeiis).

Fig. 12. The interitu' of a brachial valve.

Figs. 13, 14. Views of opposite sides of an individual in which the foramen is retained.

Huilson River group. Oxford, Ohio.
Fig. 1.5. A portion of the hinge of a mature individual, enlarged ; showing the foramen situated in front of
the area, the slight development of the deltidium of the pedicle-valve, and the great size of
that of the bi'achial valve, the lattei' being deeply grooved. X 3.
Hudson River gi'oup. Lehannv, Ohio.
Fig. 16. An enlarged cardinal view of the central portion of the brachial valve; showing the deep gi-oove
oi- central depression, the callosity conforming to the contour of the cai-diual apophyses.
Hudson River gi-oup. Oxford, Ohio.

• Since the true generic relations of the Chazy species, acoorflin(; lo tlie present arrangement, is not fully ascertaiueil,
this Bpeciitc name is retained fur the Trenton species. Should the original Leptceita incrassata, of the Chazy, prove to be a
Rafinesquina, the Trenton form will retain the name of K. Minnesotensis, N. H. Winchell.

Strcphornenidae

Palaeom.MY.Vol.IV.Ptii

(Ji'Ui'iic Illii.<lratii>ii

Plate \T

R. P Wnillieid . del .

PLATE Vlll-Continneci.

Lept^na rhomboidahs, Wilckeiis.

Fig:. 17- The exteriov of a larije pedicle-valve, which is unusually extended on the hinge-line and with ai;ute
cardinal extremities.

Niagara grou] p. Luckport, N. T.
Fig. 18. An enlargement of the articTdating apparatus of the brachial valve ; showing the central groove
of the deltidial callosity, the lobes of the cardinal process, and the dental sockets with their
low, thick inner walls (crural plates). X 3.
Fig. 19. The interior of a brachial valve.

Niagara group. Waldron, Indiana.
A view of the brachial valve; showing a foi-amen in the beak.

A profile view of a sti-ongly geniculated s;ie<-imen ; showing the contour of the two valves.
An enlargement of the beaks of an old individual ; showing the great obliquity of the foramen in
the pedicle-valve, which penetrates the sulistanoe of the shell at a considerable distance in
advance of the apex ; and also the jierforation in the deltidinm of the ojiposite valve.-
A cardinal view of a sjiecimen where the deltidium of the pedicle-valve has been lost or absorbed

and the space tilled by the callosity of the oiiposite valve which is jjerforated at the apex.
The interioi' of a brachial valve ; showing the aspect of the cardinal process from this point of
view, the character of the muscular scars, and the strong I'idge at the line of geniculation of
the valve.
The interior of a pedicle-valve ; showing the character of the muscular impressions.
An enlargement of the central cardinal portion of a brachial valve ; showing the deltidial callus,
and the slit formed by the receding or wearing of the apical pei'foi-ation.
Fig, 27. An enlargement of the intei-ior of the preceiiing specimen ; showing the same features, and also
the tubular opening into the I'ostral cavity between the divisions of the cardinal process.
Lower Helderberg grouj). Albany and SchoTiarie counties, N. Y.
The exterior of an exfoliated pedicle-valve ; showing very strong undulations and the groove left

by the receding of the apical foramen.
The exterioi- of a pedicle-valve, in which the undulations are finer and much more luimej-ons than
usual. (The L. undulata of Vanuxem.)

Corniferous limestone Western New York.
The exterior of a pedicle-valve.
The inteidor of a brachial valve.

Waverly gi'oup. Mallets' Creek, Ohio.

Fig.
Fig.
Fig.

20.
21.
22.

Fig.

23.

Fig.

24.

Fig.
Fig.

25
26,

Fig.

28,

Fig.

29.

Fig.

30.

Fig.

31

PLATE IX.

(Figures 1-34, 3« by R. P. Whitfield; 35 by F. J. SwiNION, emend.)

Legend

Fig:.

FifT.

Fiff.

Fiy.

A. Cai-iliiial area, jiediclc-valve.
a. Inner division.
a'. Outer division.
D. Deltidium, pedicle-valve.
C. Deltidinm, bi-achial valve,
j. Cardinal process.

b. Dental sockets.

s. Median septum.

X. Cardinal area, brachial valve.

t. Teeth.

a. Adductor scars.

r. Diductor scars.

Genus STROPHOMENA, Kafinesque.

P.age 245.

Strophomena filitexta, Hall.
(See Plate XIa, fig'. 3.)
Fig. 1. A view from the brachial valve of a large individual.

Trenton limestone. Eastern New Yc^rk.
Fig. 2. A view of the pedicle-valve ; showing the great concavity of the pallial region.

Trenton horizon. Mineral Point, Wisconsin.
Fig. 3. The interior of a large brachial valve ; showing the cai-dinal process, crui-al plates and undefined
muscular impression.

Trenton horizon. Phitteinlh, Wisconsin.
Fig. 4. The inferior of the jiedicle-valve of fig. 2 ; showing the covei'ed delthyrium and the character of

the muscular impressions.
Fig'. 5. The interior of a larger pedicle-valve.

Trenton horizon. Mineral Point, Wisconsin.
Figs. 6, 7. Enlargements of the external (fig. 6) and internal (fig. 7) surface striiE.

For other ilbustrations, see Palaeontology of New York, Vol. I, pi. xxxi B, fig. 3 ; and Palseontology
of Ohio, Vol. I, pi. vi, fig. ft.

Strophomena sulcata, de Veriieiiil.

Fig. 8. A view of the brachial valve ; showing the area and deltidium of the opposite valve.
Fig. 9. A fi'ont view, to show the sinuate anterior mai'gin.
Hudson River group. Ohio.
For other illustrations, see Palaeontology of Ohio, Vol. I, jilate v, fig. 5.

Strophomena nutans, J;uue.s (Meek).
(See Plate IXa, figs. 5-7.)
Fig. H. A cardinal view of conjoined valves ; showing the area and deltidia.
Hudson River group. Lebanon, Ohio.
For other illustrations, see P.aheontology of Ohio, Vol. I, plate vi, fig. 1.

Strophomena Winchelli,

SI), nov.

valve ; showing its great convexity and the fine filiform radial strise
Clifton, Wisconsin.

10. The exterioi' of the brachial
of the .surface.

Trenton limestone.

12. The interior of a brachial valve ; showing the slender bilobed cardinal process and the crural

plates, very slightly divergent fi-orii the hinge-line. The muscular area is quadrilobate, the
posterior scars lieing broader and having a faintly dendritic surface, the anterior pair being
narrow and elongate, and striated close to the median line. The figure gives an inaccurate idea
of the structure of the muscular area, which is correctly shown in figure 26, plate xx.
Trenton limestone. Janesville, Wisconsin.

13. The intei-ior of a pedi(!le-valve ; showing the character of the musculfir area, and the thickening

about the margins of the shell.

Trenton limestone. Clifton, Wisconsin.

14. .\ii enlargement of a somewhat exfoliated surface ; showing the distribution of punctse.

PalKont.NYVol.IV.Ptii

113 m Jh. n :ii ':! D 'S' D -J) '^
Strophomenidae

(■'.■ncrii IlluslriiliDns

Plate

I i

■'"^■'V'ljIllilipP'""

'{[lilililiiiJitUii^^

R.F Vftutfield.de-.

PLATK IX— Contiuueil.

Stkophomena planumbona. UiiW. ^ S(ro2)komenu rilgosa, Rafinesquc (de
• Bltiiuville).

Fig. 15. A view of the brachial valve ; showing- the usual foiiu and proportions of the species.
Fig. It). The interior of a brachial valve. On account of the great convexity [of this valve, the cardinal
process is projected ujiward at an unusual angle.

Fig. 17. The interior of a pedicle-valve ; showing the usual character of the nmscniar markings.
Hudson River group. Lebanon, Ohio.

For other illustrations, see Palaeontology of New York, Vol. I, plate x.\xi b, tig. 4 ; Pahwmtology
of Ohio, pi. vi, tig. 3 ; and this volume, plate ix a.

Strophomena subtenta, Cuarud.

Fig. 18. The extei-ior of a bi-achial valve; showing the oblicjue wrinkling of the shell about the cardinal
exti'emities, as frequently observed in /S. filitezta.
Trenton limestone. Wisconsin.

Strophomena planoconvexa, Hall.

Fig. 19. A view of the brachial valve; showing the general external characters of the species.
Fig. 20. A profile ; showing the reversed convexity of the shell.
Hudson River group. Cinci?i?iati, Ohio.
For other illustrations, see Palaeontology of Ohio, Vol. I, plate vi, tig. 2.

Genus ORTHOTHETES, Pander.

Page 253.

Orthothetes subplana, Coinad.

(See Plate IXa, fig. 19.)
Fig. 21. The interior of a pedicle-valve ; showing the muscular impressions.

Niagara group. Loekport, N. Y.
Fig. 22. A view of the brachial valve of an old example ; showing the area and deltidiuni of the opposite

valve.
Fig. 23. The inteiior of the brachial valve ; showing the character of the cardinal process, the short, ab-
ruptly terminating crural jilates, and the edge of the deltidium which is very highly developed
on this valve.
Fig. 24. A profile ; showing the subequally convex valves.
Ni.agara group. Waldron, Indiana.
For other illustrations, see Palseontology of New York, Vol. II, plate liii ; and Twenty-eighth Re-
port en the New York State Museum, plate xxi.

Orthothetes Woolworthana, Hall.

Fig. 25. A view of the bi-achial valve ; showing the genei-al form of the shell and the area and deltidium

of the opposite valve.
Fig. 26. A profile of the same specimen.
Fig. 27. An enlargement of the cardinal process ; showing its bilobed character from this point of view,

and the high crural plates ending abruptly at the crural bases. X 3.
Fig. 28. A posterior view of the same parts ; showing the lobation of each branch of the cardinal jirocess,

and the additional lobes on each side between the process and the dental socket.s, thus making

the posterior face of the divaricating process appear six-lobed. X 3.
Fig. 29. Another anterior view of the cardinal process, in wbicb the lobes are rather more prominent and

the ci-ural bases less pronounced. X 3.
Pig. 31. The interior of a pedicle-valve ; showing the deltidium and muscular impressions.
Lower Helderberg group. Near Clarksville, N. T.

Orthothetes Chemungensis, Comad, var. Pandora, Billings.

Fig. 30. An enlargement of the hinge area, cardinal process, crural plates, etc., of the specimen, tig. 3,
plate X ; placed upon this plate by mistake.

PLATE IX— Continued.

Orthothetes defokmis, Hall.

Kig-. 32. Fi-ont view of an indiviiiual I'etaiiiing both valves.

Lower Heldei-berg- group. Borst's Mill, Schoharie caunty, N. Y.
For illusti-ations of other species of the genus, see Palfeontolog-y of New York, Vol, II. plate xvii,
and ibid. Vol. IV, plates ix and x ; and this volume, plate xx, tigs. 8, 9.

Genus HIPPARIONYX, Vanuxem.

Page 257.
HiPPARIONYX PROXIMUS, VililUXeiU.

FifT. 33. The interior of a l)i-achial valve of a young indivi<lual ; showing the strongly bifurcated process,
high vertical crural plates, short median septum, and faint muscular scars.
Oriskany sandstone. Cumberland, Maryland.
Fig. 34. The cardinal process and its adjoining jjarts. .as obtained from a gutta-percha impression of a
natural cast of the interior ; natural size. This iigui-e shows very clearly the almost complete
obsolescence of the cardinal area, the marginal crenidations extending nearly to the base of the
l>rocess.
Fig. 35. A natural cast of the interior of a pedicle-valve ; showing the impressions of the adductoi' and

diductor musc'les.
Fig. 36. The exterior of the cardinal area of the pedicle-valve ; showing the covered delthyrium and the
projecting teeth. From a gutta-percha imj)ression.
Oriskany sandstone. Alba^iy county. N. Y.
For other illusti-ations, see Palseontology of New York, Vol. Ill, plates Ixxxix ; xc ; xci, figs. 4, 5 ;
and plale xvA of this volume.

PLATE IX A.

(Figures 1-27 by R. V. Whitfield.)

Leg'enrl. D. Deltidium, pedicle-valvi'.
C Deltidium, liraohial valve,
t. Teeth.

b. Dental sockets.

c. Crural plates.
X. Crural bases.

p. Pedicle muscle.

A''. Anterior jiddui^tors.

a. Posterior adductors.

r. Did actors.

V. Vascular sinuses.

Genus KAFINESQULNA, okn. nov.

Page 'iSl.

Rafinesquina deltoidea, Conrad.

Fig-. 1. The exterior of a pedicle-valve ; showing its regular convexity and deep anterior deflection, the

radiating strije of subequal size, and the concenti-ic corrugations.
Pig. 2. Profile of the same specimen j showing the regular convexity from umbo to anterior margin.

Trenton limestone. Jacksonburg, N. Y.
Fig. 4. An impression of the exterior surface of the brachial valve ; showing its subtriangular outline as
usually developed in this species, ami the flattened, scarcely concave circumbonal area.
Trenton limestone, Middleville, N. Y.
This 6gure is from the oi-iginal specimen used by Mr. Conrad, and is the subject of the drawing
by him reproduced in Palseontology of New York, Vol. I, plate xxxi .1, fig. S/. That figure,
however, gives the valve a convexity which it does not possess. For furthei- illustration of the
species, the other figures on the plate cited may be consulted.

Fig.

Genus STROPHOMENA, Rafinesque (de Blainville),

Page 245.

Strophomena Conradi, .sp. nov.

3. View from the brachial valve ; showing the reversed convexity of the valves, and the fasciculate
surface strise without conceniric rugse.

Trenton limestone. Jacksonburg, N. Y.

Strophomena nutans, Jiunos (Meek).

Fig. fi. The exterior of a brachial valve.

Fig. 6. The interior of a pedicle-valve ; showing the character of the muscular impressions and vascular

markings.
Fig. 7. The central cardinal portion of the brachial valve; showing the bilobed cardinal process, the
curved crural plates, and the muscular impressions. X 3.
Hudsou River group. Oxford, Ohio.
Foi other illustrations, see PaliEontology of Ohio, Vol. I, plate vi, fig. 1.

Strophomena planu.mbona, Hall (^(S'. ni^osa, RntinesinK').

Fig. 8. An enlargement of the cardinal process and crural plates. X 2.

Fig, 9. The corresponding portion of the opposite valve ; showing the irregularly crenulate<l charactei' of
the surface of the teeth. X ^.

Hudson River gr<iup. Oxford, Ohio.

Strophomena filite.\ta. Hall.

Fig. 10. The interior of a brachial valve ; .showing the cardinal process, muscular area, and the elevated
median ridges of the vascular system {i}.

Hudson River group. IVaynesville, Ohio.

Fig. 11. The interior of a pedicle-valve ; showing the limitation of the muscular area by an elevated bor-
der, which is continuous from the dental plates.

Fig. 12. Exterior of a brachial yalve ; showing the tendency to plication of the surface.

Fig. 13. A cardinal view of a specimen retaining both valves, and showing the resupination of the shell.

PLATE IXa— Continueii.
Fig-. 14. A curtiiiial view of the specimen illu.stiated on j)late ix, tig. 1.

Ti-enton limestone. New York.
Fig. 1.5. An enlarged view of the interior of a pedicle-valve ; showing- the vascular mai-king-s. which are
rarely seen in this species.

Hudson River g-ronp. Waynesville, Ohio.

StROPIIOMENA ? (StROPHONELLA ?) PATENTA, Hall.

(The actual relations of this species to STRorHOMBNA and Strophonella are not yet fully determined.)
Fig. 16. The interior of a large pedicle-valve ; showing the muscular area.
Fig. 17. The exterior of the pedicle-valve.
Fig. 18. The interior of a smaller pedicle-valve.

C-'linton gi-oup. Reynale's Basin, N. Y.

Genus OETHOTHKTES, Pander.

Page '253.

Orthothetes subplana, Conrad.
(See Plate IX, figs. 21-2ii.)

Fig. 19. An enlargement of the central cardinal portion of the brachial valve ; showing the gi-eat develop-
ment of the deltidial callosity, the rounded, somewhat unequal lobes of the cai-dinal process,
and the thin, abi-upt, nearly vertical crural plates. X 3.
Niagara group. Waldron, Indiana. ,

Orthothetes in^qualis,* Hull.

Fig. 20. The interior of a pedicle-valve.

Fig. 21. A small brachial valve ; showing a tendency to a fasciculation of the striiB.
Fig. 22. A cardinal view of an internal cast of the brachial valve.

Fig. 23. The intei-ior of a bi-achial valve. In this figure the lobes of the cardinal process are not suffici-
ently distinguished from the crural plates.

Wavei-ly gi-oup (Kinderhook). Burlington, lotoa.

Orthothetes inflatus, White ami Whiltiekl.

Fig. 24. A cardinal view of one of the original specimens, which is an internal cast of the brachial valve ;
showing the impression of the cardinal process and ailductor muscles.

Fig. 2.5. The cardinal process, enlarged from a gutta-percha impression ; showing its appearance on the
anterior face. Tlie crural bases (x) appear very abrupt at the termination on account of the
impression having been taken without the shell being first entirely i-emoved from the matrix.
Waverly grouji (Kinderhook). Burlington. Iowa.

Orthothetes desideratus, n. sp.

Fig. 26. A view of the brachial valve of an internal cast ; showing the muscular impressions.
Fig. 27. A caidinal view of the same specimen.
Wavei-ly group. Ohio.

• The reference to this species in the Report of the New York .St.ite GeoloKi.st for 1882, explanation of plate xi A (= IXA)
as Slreptorhynchus aquivalvia, is erroneous. The shell is the Orthis inegualis, llall, Geol. Rep. of Iowa, p. iSO, plate ii, ligs.
t>, a, b, c.

33 31 ^ 'Q 'H "I B :F B -J3 ^

Sirophor.ienidce .

11 a

16 P a

,,#

23 .J b

PlatelXA

D 6

15 D i

25 !

KP \ftit:>e:i

PLATE X.

(Figures 1-14, 16, IS-JS by K. 1'. Whitkield; 16, 17 by F li. Mkkk.)

Leg^ncl. U. Deltldium. j. Cariliiiiil process.

A. Cardinal area. c. (Jrurii.

I. Umbo-lateral slope.i. s. Meiiiati neptura.

t Teeth, a. A<kluctor scafs.

d. Dental lamellae. r. Didiictoi- scars,

b. Dental sockets.

Genus ORTIIOTIIETES, Fischku i.k W Ai,r)iiKiM.

Orthothetes Chemungensis, Coiuad, viir. Pandoka, Billings.

Fig. 1. A view from the bi'achial valve ; showing the cardinal area and deltidiura of tUe oppi'site valve.

Corniferous limestone. Caledonia, N. Y.
Fig-. 2. The intei-ior of a brachial valve, drawn from a gutta-percha impre.ssion ; showing the muscular
area, and, imperfectly, the cardinal process.

Schoharie grit. Schoharie, N. Y.

Fig. 3. The interior of a larger brachial valve ; showing with more accuracy the crural plates and the
adductor scars.
Plate IX, Fig. 30. — An enlargement of a part of the hinge area, the cardinal process, crural
plates and muscular impi'essions of the preceding specimen.

Fig. 4. The interior of a pedicle-valve; showing the low deltidiuni, with unsui>ported teeth, the adductor
and iliductor scars.

Corniferous limestone. Caledonia, N. Y.
Fig. 5. The interior of a pedicle-valve, drawn from a gutta-percha impi'ession.

Schoharie grit. Schoharie, N. Y.
Fig. 6. An internal cast of the pedicle-valve ; .showing the Habellate diductors and the impression of a
broad median ridge.

Corniferous limestone. Western New York.

Orthothetes ChEiMungensis, Connul, vjir. ai.ternata, Hall.

Fig. 7. The interior vt the brachial valve ; showing the characteristic cardinal process.
Hamilton group. Caiiandaigua Lake, N. Y.

Orthothetes Chemungensis, Conrad, var. arctostriata, PLill.

Fig. 8. An internal cast of the pedicle-valve ; .showing the imju'ession left by the rather unusual develop-
ment of the ridges surrounding the adductor scars and miiting in the median line sepaiatiug
the diviuctors. This ridge is not a septum but merely the thickening of the edges of the mus-
culai- scars. X '^.

Hamilton group. Western New York.

Orthothetes Chemungensis, Connul.

Fig. 9. A caidinal view of a specimen ; showing the irregular form of the shell, the usual width of the
area, and the character of the deltiilium.

Chemung group. South-western New York.
For further illustration, see Palaeontology of New York, Volume IV, [ilates ix and x.

Genus DERBYA. Waagen.

Page 261

Derbya crassa, Meek ;ind Hayilen.

Fig. 10. The interior of a brachial valve ; showing the cardinal process and muscular impi-essions. The
former is repi'esented as having the lobes upon its edge and too acutely angular.

Fig. 11. The interior of a pedicle-valve, with strong median septum dividing the muscular area, and
highly developed teeth projecting into the cavity of the valve.
Coal Measures. Near Winter.iet, Iowa.

PLATE X— Contiuueii.

Derbya robusta, Hall.

Fig-. 12. Thf exterior of a compressed brachial valve, in whicli the radial strife of the shell are .^itrongly

developed.
Fig. 13. An enlargement of the cardinal process from another specimen.
Figs. 14 (17 in eri'or], 15. Profile and brachial views of a large individual ; showing the external ch.arac-

tei's of the species.
Fig. 16. The interioi- of the cardinal portion of the pedicle-valve ; showing the character of the muscular

scai-s, the strong but short median septum, projecting teeth and the convex deltiilium. The

projecting tooth on the right-hand side of the figure has Tiecome double fiom abnormal growth.
Fig. 17. The exteiior of a peilicle-valve ; .showing the chai'acter of the striae, which differ in some degree

fi'om their uniformity .shown in the specimen represented in tigs. 14 .and 15.
Coal Measures. St. Clair county, lUiJiois.
For other illustrations, see Palseontology of Eastern Nebi-aska, plates v and viii.

Genus MEEKELLA, White and St. John.

Pag-e 26t.

Meekella striatocostata, Cox.

Fig. IS. Protile of a specimen retaining both valves; showing the great elevation of the cardinal area of

the pedicle-valve.
Fig. 19. Cardinal view of a Larger individual ; showing the high area, narrow deltidinm. and the bases of

the ci'ural plates in the brachial valve.
Fig. 20. A view of the pedicle-valve of the same sjiecimen.
Fig. 21. A cardinal view of a specimen from whii'h the apex of the peilicle-valve has been removed to

show the dental lamellse.
Fig. 22. An enlargement of the cardinal process ; showing the extreme elevation of the lobes and the cru-
ral plates. The central iiortion of the process is incorrectly represented as having three instead

of two lobes.
Fig. 23. A longitudinal section of the specimen i-epresented in fig. 19 ; showing the extent of the dental

lamellae and crural plates, to the latter of which one of the ci-ura is attached.
Coal Measures. Near Whiterset. Iowa.
For other illustrations, see Transactions of the Chicago Academy of Nafnral Sciences. Volume I,

PI1. 120, 121 ; and Palseontology of Eastern Neljraska, jilate v.

Palceont.Ny.VolIV.Ptii.

:ii Hi jx ir; :iij: 2 cj IP ^id icj ^ .

Strophomenidae

(■'(•iicric lUu.slriilioiis

PlateX.

C 3 j

D * a t

.-;#■'

^

1 \v

'^•"«Huii^»»'

#

-' ■•■••J<s

11

If.

if

iff

-' '^^e:;J;>^-^'-

^l^ff^

^.#

1 ^ /'■'

aa .

, ]

'<fe--

X /

^«i^>:v

R.PVvTiitfield.del.

PLATE XI.

(Figures l-2'.> by R. P. Whitiield.)

Legend. D. Dellidiuin, pcilide-valve. s. Median septum.

C. Deltidiuin, braehial valve. j. Cardinal jjroi-es.s.

t. Teeth. r. Diductor sears,

d. Dental lamellEe. a. Anterior adihi<-,tiirs.

b. Dental sockets. a'. Postei-ior addiiclcirs.

c. Crural plates.

Ge.nus I)P:KBYA. W aace.n.

I'afCc-iKI.

Dkkbya Keokuk, Hall.

Figs. 1, 2. An internal cast and g-iitta-percha inijn'ession of the central cardinal .irea. viewed (Voni the bra-
chial valve ; showing the character and extent of the muscular area, cardinal process, dental
lamellse and median septum.

Keokuk beds (Knobstone group). Nem Providence. Indiana.
Fig. 3. An jiartial ca.«t of the interior of a pedicle-valve; showing the muscular scars and impression of
the median septum.

Keokuk beds. Keokuk. Iowa.

DeKBYA (?) BILOBA, Hall.*

Fig. 4. A cardinal view; showing the ventricose brachial valve and short area of the jiedii-le-valve. X 2.
Fig. 5. A view of the brachial valve ; .^ihowing the bilobed contour of the shell, obdurate outline, the short
cardinal area and deltidium of the opposite valve. X 2.
Coal Measures. Winterset, Iowa.

STREl'TORHYNCHUS. King.

Page 267.

Streptorhynchus Hallianus, Deihy.

Fig. 6, A view fmm the brachial valve of an entire shell.

Fig. 7. A posteiior view of the canliual process ; showing the lobatiou of the jiosterior face, the elevfited

crui'al plates and the grooved deltidium. X 2.
Fig. 8. An enlai'ged view of the s.ame parts, from above ; showing also the character of the adiluctor im-
pressions. X 2.
Fig. 9. The cardinal proce.ss of a lai-ger indiviilual ; showing the gi-ooving of the extremities of the lobes.
Fig. 10. A profile of the same ; showing the backward extension of the process and the great elevation of

the crural plates. X 2.
Fig. 11. A posterior view of the same. X 2.

Fig. 12. The cardinal process of another specimen ; showing a greater elevation and deeper bifurcation.
Fig. 13. The exterior of an unsymmetrical pedicle-valve ; slightly restored about the left ante-lateral

margin, ami showing the strongly alternating striae.
Fig. 14. The interior of the same valve ; showing the unsupported teeth, and the character of the uuiscu-

lar scars.
Fig, la. The exterior of a pedicle valve, having a plicated exterior similar to that of Meekklla and Strep-

torliynchtis peHiniformi.'!. X>a\\dsvu. The shell is unsymmetrical and the outline is partially

restored.
Fig. 16. The interioi- of the same specimen ; showing the cardinal area, closed delthyrium, the projecting

teeth, and the fiabellate nmscular impression.
Fig. 17. A view looking into the umbonal cavity of the specimen repi-esented in tig. 14 ; showing the

absence of dental lamellfe and median septum.

Upper Carboniferous. Bomjardim and Itaituha, Prwoince of Para. Brazil.

Kepoit of the New York State Geologist for 1882 (pub. 1883), explanation of plate (xi) 41, flgs. 4 and 5.

PLATE XI— Continuea.

Genus DERBYA, Waagen.

Page 261.

Derbya Correana, Derby.

Fig. 18. Cardinal view of an internal cast of the pedicle-valve ; showing^ the cavities left by the dental
lamellse and median septum.

Fig. 19. The same specimen, viewed from above ; showing the extent of the median septum.

Fig. 20. Cardinal view of an internal cast having a much higher ai-ea and a somewhat distorted beak.

Fig. 21. The exterior of a high cardinal area; showing the longitudinally grooved deltidium perforated
near the lower part by a small oval foramen, which is probably accidental. From a gutta-
percha impression in a natural mould.

Fig. 22. The interior of a pedicle-valve ; showing the union of the dental lamHllje with the median septum,
thus forming a subapical vault.

Upper Carboniferous. Itaituha, Brazil.
For the original illustrations of the two preceding species, see Bulletin of the Cornel! University,
Vol. I, No. 2.

Palaeoni NYVolIVPtii

m m. Jk B "Ji 1 £) 'j^ z) "Ji js.

S:rophorMonida3 -

(ii'l\Cfli llliislfolioiis

f late A.

3^ ^ d t

'lfwi,y '

"'-".'/■|':vr,v 1

PLATE XIa.

(Kigures i, 2, 4-10, 12 at by G B Simfson; 3 by J. C. McConnbll; 11 by E. Emmons.)

Legend. D. Delti.Uinn. mf. MusiMilar fult-ra.

t. Teeth. s- Median seiiUiiii.

j. Cariliiial |ir(ice.-<s. a. AdciiK'tor seai-.s.

fp. Crural plates. r. Didiictor scars,

b. Dental socket.s. x. Cicatrix of attachment.^'

Genus STUOrHOMENA, Kai<'inesque (dk Hi.ainvilm:).

(See Plates IX and IX A. J
Page 245,

Stkoi'homkna \yiscoNsiNENSis, Whitfiold.

Kitf. 1. Cardinal view of a specimen ; showing the broad cardinal area and deltidiinn of the pedicle-valve,

the concavity of the bi'achial valve at its beak and its great convexity over the pallial I'egion.
Fig. '2. Profile of the same specimen ; sliowing the degree of retrorsion in the umbo of the pedicle-valve.
Hudson River group. Wilmington, Illinois.
For other illustrations, see Geology of Wisconsin, Vol. IV, plate xii, tigs. U-13.

StKOPHOMENA FILITEXTA, Hall.

(See Plate IX, tigs. 1-7 ; and Plate IXa, tigs. 10-l.i.)
Fig. 3. The interior of a brachial valve; showing the articulating apparatus and the lol>ate vascular (f)
ridges extending forward from the impi-ession of the adductor muscles.
Hudson River group. Richmond, Indiana.

Stkophomena fluctuosa, Billiiigtf.

Fig. 4. Protile view ; showing the resupination of the lower valve and the great anterior deflection of the

shell.
Fig. h. The cardinal area ot the pedicle-valve, enlarged; showing the deltidium, the striated path of

gi-owth of the dental ridges, and at [t) the pectinated margin of one of the teeth, the other not

being well preserved. X 3.

Hudson River group. filp7-inff Valley. Minnesota.

Stkophomena nutans, Junies (Mei'U).

(See Plate IXa, figs. 5-7.)
Fig. H. The interior of a pedicle-valve.

Fig. 7. Profile of the same specimen ; showing the great elevation of the interrui)teil ridges surrounding
the muscular area, and the median thickening on the anterior margin.
Hudson River group. Weiseburgh, Indiana.

Stkophomena sulcata, cle VfriK-iiii.

(See Plate IX, figs. 8, 9.)
Fig. 8. The interior of a brachial valve ; showing the peculiar character of the cardinal process, the
. strong curved crural plates, and the thickened muscuhvr area.
Hudson River group. Oxford, OMo.

Genus ORTHOTHETES, Fischer de Waldheim.

(See Plates IX and IXa.)

Page 253.

Oktuothetes SUBPLANA, CoiHiwl.

(See Plate IX, figs. 21-24.)

Fig. 9. Cardinal view of an internal csist ; showing the impression of the inner face of the cardinal process.

Niagara group. Bridgeport. Illitiois.
Fig. 10. The cai-ilinal area of a brachial valve, enlarged. The lobes of the cardinal proc^ess are enclosed
behin.l by a well developed cieltidiuni, and the crural plates are short and erect, terminating
abruptly. X 3.'

Niagara grou] I. f\'aldro7i, Indiana.

rLAFK XI A-Coiililiucil-
Fig 11. An internal cast of the, In-achial valve.

Fig-. 12. The oanlinal iirocess, enlarf<-e<l. The lobes ave sti-ongly detineil, the crural plates short and
sliffhtly recui-ving where they join the bottom of the valve, producing a thickening of the den-
tal sockets. X 3.

Lower Helderberg group. Albany comity. N. Y.

OUTHOTHETES PKAVA, Htlll.

Fig. 13. The interioi' of a brachial valve retaining the cardinal process, fiabellate nuiscular scai-s and traces
of vascular sinuses.

Upper Devonian. Hackberry Cf-rove, Iowa.

OuTHOTHETES CnEMUNGENSIS, C'olllMil.
(See Plate X, tig. 9.)
Fig. U. The cardinal process, enlarged; showing upon its summit the edges of the lobes on the posterior
face. The transverse grooves at the junction of the piocess with the ci-ural plates are made to
appear somewhat too abinijit. Frequently the lobes of the cardinal pi'ocess are moi'e deeply
divided than in this specimen. X 2^.

Hamilton group. We.itern. New York.
For further illustration, see Palseontology of New York, Voliune IV, plates ix and x.

Okthothetes CKENisTUiA, (Phillip.-^ ?) Meek.

Fig. l."). The cardinal process, enlarged ; showing the character of its inner surface and the extent of the
cnnal plates. X 3.

Waverly group. SciotovUle, Ohio.
For other illustration, see Palaeontology of Ohio. Volume II, plate x, tig. 5.

OrTHOTHETES LENS, AVliito.
Fig. 11). The exterior of a pedicle-valve.

Fig. 17. U'he interior of the same valve ; showing are.a, <leltidium, teeth and muscular imjiressions.
Fig. 18. The exterior of a brachial valve.

Fig. Hi. The interior of the .«ame valve; showing cai-dinal process, muscular iinpressicms and ovarian
markings.

Fig. 20. The cardinal process of the same specimen, enlai'ge<l to show its structure. Its outer face is cov-
ered l)y the deltidium, which conforms to the grooved surface of the lobes. The ci'ural plates
are strongly recurved at their liases about the dental sockets. X 3.
Choteau limestone. Louisiana, Missouri.

Fig. 21. A very young jiedicle-valve which retains the perforation at the apex of the deltidium. X 8.

Fig. 22. Cardinal view of the same specimen ; showing the height of the area and the prominence of the
deltidium. X 8.

Choteau limestone. Pike county. Missouri.

Genus DERBY A, Waagen.

(See Plates X, XI and XIb.)
P.iRe 261.

Derbya Broadheadi. sp. IIOV.

Fig. ^3. Carduial view of an entire, mature indivi<bial ; showing the rugose and somewhat irregular jied-

icle-valve, the more .symmetrical brachial valve bearing a median sinus.
Fig. 24. Protile view of the sanje specimen.

Upper Coal Measures. Ka7i.ia.i City. Mis.'smiri.

Derbya rugikosa, sp. nov.
Figs. 25, 2t;, 27. 'ITiree views of an internal east in chert, retaining portions of the inner laminae of the
shell. Both valves wei^e of iriegular growth, the br.'u:hial valve not having the median sinus
of the preceding species. Thei-e ai-e many points iif similarity between this fossil and the
Orthis .senilis, Philliiis (Streptorliyiichm creni.sMa. var. senilis. Davidson), which has been shown
liy Dkbbv to have a septum in the jiedicle-valve.

Keokuk limestone. New Providence, Indiana.

Pal2eont.N,Y.Vol.!V.PT!i = Vol vm.

.Strophomenidas

''Piieric Ilhislrations

Plate XI A

i 3,3;raT3scr. -

1 r.,..Asi.iith..

PLATE XiA— Coutinueil.

Derbya crassa, Meek iiiul Huydon.
(See Plate X, tigs. 10, 11 ; and Plate XIu, &gs. 23, 24.)
Fig. 2S. The interior of a small brachial valve.

Fig. 29. The caniinal process of the same specimen, enlarg-ed ; showing the lobation at its sinnniit anil the
extent of the crural plates. X 3.

Upper Coal Measures. Kansas Citji, Missouri.
Fig. 30. The extei'ior of a laiger pedicle-valve.

Fig. 31. The interioi- of a small pedicle-valve; showing the median septum ami large muscular scars.
Fig. 32. The interior of a large and old pedicle-valve ; showing the median septum, the thickeniTig about
the muscular area, due to age, and marks of vascular sinuses.
Upper Coal Measui-es. Winterset, Iowa.
Fig. 33. The interior of a large brachial valve which is referi-ed to this species with some doubt. The
crural plates are well produced, partially enclo.sing arVmrescent .scais of the adductor muscles.
The valve is unusually convex for one of this species.

Upper Coal Measures. Kansas City. Missouri.

For other illustrations, see Palseontology of Eastern Nebi'aska, jilate \-. tig. 10, and plate viii,
fig. 1.

Derbya Bennetti, sp. uov.

Fig. 34. The exterior of a pedicle-valve which letains the scar ol altachnieut at the umbo.

Fig. 3.5. The opposite side of the same specimen ; showing the height of the cardinal area of the pedicle-
valve and the median sinus on the brachial valve. A Crania is attached to the apex of the
latter valve.

Fig. 3(5. Profile view of another specimen.

Fig. 37. Cardinal view of the same; showing the high cardinal area and the la<-k of .symmetry in the i>ed-
icle-valve.

Fig. 38. The same specimen after having the pedicle-valve cut hoi-izontally near the hinge. The section
shows the unsu)>poi'ted dental ridges, the tips of the grooved caniinal process, and the extrav-
agant development of the median septum.

Fig. 39. A similar section of the same specimen near xhe apex. Here the median se|itiun is coalesced with
a solid callosity filling the apical portion of the deltidial cavity.
Upper Coal Measures. Kansas City, Missouri.

PLATE XI B.

(Figures 2-17, 20-24 by G. B. Simpson; 1, is, 19 by E. Emmons.)

Leg'end. j. Canlinal process. rv. Rostral vault,

(i. Dental lamella;. dr. Dental lidges,
t. Teeth.

Genus DERBYA, Waagen.

Page 261.

(See Plates X, XI and XIa.)

Derbya, sp. iiulet.

Kijf. 1. The interior iif a large and very convex brachial valve; showing the cardinal process and short,
vertical crural plates, from the base of which a thickened ridge extends about the muscular
area. The accompanying outline profile .shows the convexity of the valve.
Upper Coal Measures. Kaiisas City, Missouri.

Derbya cymbula, sp. nov.

l''ig. 2. Cai-dinal view of a large individual, somewhat incomplete at the apex ; showing the height of the
area, the median groove on the surface of the deltidium, and the tendency to irregular growth
in the pedicle-valve. The broken .surface at th(; apex of the pedicle-valve shows evidence of
the existence of a median septum.

Fig. 3. View of the bi-achial valve of the same specimen ; showing its form, contour and the character of
the sui'face ornamentation.

Figs. 4, 5. Cardinal and protile views of a small individual, jirobably belonging to the same species. In
this specimen the irregular growth is very pi-ondunced in both valves.
Upper Coal Measures. Near Ka/nsas City, Missouri.

Derbya Ka.skaskiensis, McChe.sncy.

Fig. li. The interior of an imperfect pedicle-valve, iu which the median septum unites with the dental
lamellse, forming an elongate deltidial or i-ostral vault, like that seen in Derbya Correana, Derby
(plate xi, tig. 2'2).

Chester limestone. Crittenden county, Kentucky.

Derbya robusta (?), Hall.

(See Plate X, tigs. 12-17.)
Fig. 7. The interior of a brachial valve of .an old shell, which jirobably belongs to this species. The
cardinal process is much thickened and slightly irregular in its growth, the niusculai' area deeply
excavated but not well defined, and the pallial region covei'ed with ti'aces of the vascular sinu-
ses. The outline at the left shows the convexity of the valve.
Ujiper Coal Measui'es. Winterset, Iowa.
Fig. 8. The interior of a pedicle-valve, having a conijiaratively narrow caT'dinal ai'ea, a relati\ely small
flabellate mnscular impiession, and a short median septum.
Upper Coal Measures. Near Ka^isas City, Missouri.

Genus STKEPTOEHYNCHUS, King.

Page 267.

Streptorhynchus pelargonatus. Sflilotlicim.

Fig. It. An internal cast of the two valve.s; showing- the position of the deltidinm and dental ridges of
the pedicle-valve, the inner face of the canlinal iii'ocess, and the nuiscidar impressions of the
brachial valve. X '^■

Figs. 10, 11, 12. Anterior, profile and cardinal views of a specimen which retains the shell; showing the
contour and general external I'har.'icters of the species. X 2.

Fig. 13. An intei'nal ca.st of the pedicle-valve ; showing the form of the mu.scnlar ai'ea, without evidence
of a median septum. X 2.

Fig. 14. The interior of the cai'dinal portion of the articulated valves ; showing the dental ridges and inner
surface of the deltidium, the i-ardinal process, crural plates and the chariicter of the articula-
tion. X 5.

Permian Formation. Posneck, Silesia.
For f\uther illustration, see GKiNrrz, Dyas, plate xvi, figs. 26-34 ; Davidson, Permian Brachiopoila,
plate ii, tigs. 32-42.

Strophomanidac

Palseont. N Y.Voi.IV.P: ii = VoI.V!!!

Cu-UIM U Illu^ll-.llll.ll-

PlateXl.B.

G-B Simpsor. del

Phii.Asi.lith.

I"I,ATE XlB— Contimieil.

Stueptokiivnctius Ur-RICHt, .sp. IIOV.

b'ig-. 1'). The iiiterioi- of ii pediclo-valve, i-fft-i-red to the gtnius on account of the peculiar form of the shell
anil the absence of nieilian septum or dental plates.

Chester limestone. Crittenden county, Kentucky.

Genus DERBY A. Waagen".

P:lgc 281.

DeUBYA (?) COSTATULA, Sp. IIOV.

Fiff. IB. View from the I ira«:lii:il valve of a small specimen, which shows the characteristic surface orna-
mentation of this species. This consists of strong radial ribs alternatin-f with fascicles of two,
three or four finer strias. X 2.

Fig. 17. The cardinal process of a brachial valve .similar in external characters to that of the prei-eiliuff
specimen. X 3.

Chester limestone. Orittenden county, Kentucky.

Genus MEEKELLA. \Vhite and St. John.

Page 26t.

(See Plate X, fis^.s. 18-23.;

Meekella occidentalls, Newberry.

Fig-. 18. View of the brachial valve of an internal cast which retains a portion of the shell over tne cardinal
area of the pedicle-valve. The deltidiuin of this area shows the same struc-ture as in the fol-
lowing species and in the genus Tripleita, a considerable portion of the coverving between the
dental ridges being flat or slightly concave, the convex riilge being conlineil to the middle of
the plate. The apex of the brachi d valve is removed, showing (imperfectly in the figure) the
basal portion of the inner surface of the cardinal process.

Fig. 19. An incomplete internal cast of the pedicle-valve; showing the exten.sion and convei-gence of the
dental lamellse and tlie tine radial lines upon the surface of the plications.
Both figures are fi-om the original specimen of Orthisina occidentals. Newberry.
Upper Carboniferous limestone. Canon of Diamond River.

Meekella striatocostata, Cox.

(See Plate X. figs. lS-2.3.)
Fig. 20. Cardinal view of a large, symmetrical individual, essentially an intei'iial cast in chert ; showing
the position of the dental and criu'al plates.

Uppei' Coal Measures. Winterset, Iowa.
Fig. 21. Cardinal view of a distorted specimen, with an unusually high cardinal area.
Fig. 22. The form of the cardinal process, from a gntta-pei'cha impression of a natural mould. X 3.

Upper Coal Measures. Lawrence county. Kansas.

Genus DERBYA, Waagen.

Page 261.
(See Plates X, XI and XIa.)

Dekbya crassa, Meek and Haydeii (?).
(See Plate X, figs. 10, U ; and Plate XIa, figs. 28-33.)
Fig. 23. A portion of the internal surface of the lirachial valve of Productus NebrasceiwiL's, to which are
attached sever.al minute jiedicle-valves, some of which show the presence of a broad cardinal
area, deltidium and a median septum. It will be observed that most of the attached shells
have their hinge-lines parallel to that of the Proddctu.s, though their relative positions ai-e in-
verted. X 3.
Fig. 24. A further enlargement of thi-ee of these .shells ; showing all the details of structure that are re-
tained. These attached valves seem to be the young of some strepforhynchoid spet-ies having
a median septum in the jiedicle-valve, and as Derhya cra.ssa is the most abimdant of tliese forms
in the associated fauna, the fossils may be tentatively referred to tliis species. X 10.
Upper Coal Measures. jVear Kansas City. Mis-wuri.

PLATE XIc.

|(KiK«rcs 1-3, 5-fl, 13, 14, 17, iS, iO-iMlby K. I". WnnriEl.1); i. 10-12, 15, Ifi, l:i, 25->8 by E. Emmons; 'iS, 24 by C. E. Beecher;

2U-39 copies.)

Legend. F. Foniiueii, il. Dental lanielliE.

ps. Delticiiiini. a. Anterioi- adducUn-.s.

c. Crura. a'. Posterior adductors,

j. Cariliual [irocess. r. Diductors.

Genus TKIPLECIA, Hall.

Page 2fi9.

Tkiplecia extans, Emmons.
Fig. 1. The bia<rhial valve of an individual of average dimensions.
Fig. 2. An anterior view of the same.

Fig. 3. A cardinal view of the same. The delthyriuni, whiuh is here represented as open, is obscured in
the specimen.

Trenton limestone. Lowville, N. ¥.
Kig. 4. The cardinal area of flie pedicle-valve ; showing the apical foramen and the convex deltidial
covering.

Ti-enton limestone. Carlton Islrni.d, N. Y.

Fig. 5. A cardinal view of a brachial valve ; showing the bifurcated cardinal process extending into

the matrix.
Figs, t), 7. Anterior and posterior views of a normal imlividual. the latter showing the impressions of the

dental plates (if the pedicle-valve. X 2.

'I'renton limestone. MiddleinUe, N. Y.

Tkiplecia nucleus, H:ill.

Figs. 8, n. Cardinal and profile views of a normal individual, the former showing the foramen and deltid-
ium of the pedicle-valve. X 2.

Trenton limestone. Middleville, N. Y.

Triplegia spikikekoides, McCoy.

Fig. 10. An intei'nal (^ast of the brachial valve.

Fig. U. A cardinal view of the same specimen ; showing the impi-essions of the crui'a (c) and of the bifur-
cateil cardinal process.

C'ai'adoc sandstone. North Wales.

Tkiplecia Outoni, Meek.

Fig. 12. The interior of the pedicle-valve ; showing the narrow area and much thickened teeth.
Fig. 18. The extei-ior of a brachial valve.

Fig. 14. Cardinal view of a specimen having the valves in cnnjiuiction ; showing the cardinal area, fora-
men and deltidium.
Fig. 1."). Interior of the cardinal region of conjoined valves ; showing their mode (jf articulation.
Fig. 11). Pi-otile of the apical portion of the brachial valve ; showing the curvature of the cardinal process.
Fig. 17. The (-enti-al i-ai-dmal jiorlion of an old and thickened brachial valve. The tips of the cardinal

process and of one of the ci-ui-a have been bi-oken.
Fig. 18. The external cardinal area of conjoined valves. X 'A-

Fig. 19. Posterior view of the cardinal proces.s ; showing the grooves on the outei- face nf its branches.
Fig. 20. Innei' view of the same feature in a youngei- shell.
Clinton group. Dayton. Ohio.
For othei- illustrations, .see Palasontology of Ohio, Volume I, jilate xv, tigs. 1 a-k.

Tkiplecia insulakis, Eicliwuld.

Pig. 21. Posterior view()f an internal cast of the conjoined valves; showing, in the brachial valve, the im-
pressions of the antertor and postei-ior adductor.^, the crura and cardinal proce.ss, and, in the
pedicle-valve, the extent of the dental lamelUe.
(-'aradoc .sandstone. Ty-lsaf, Wales.

1© m .^ (s m JL m IF udiid^

Strophomenidae

Palasont N Y.Vo! TVPt n = Vol VUi Immu^i n lllnsi.Miu.ns

Plate XL C

K PWutfieid and i:, .Em:

"'r.ri.Asthth.

PLATK XI c— Continued.

Triplegia Wknlockexsis, Duvidson.

Fig. 22. A cast of tlie interior of t ho iieiiicli^-valve ; showiii{>' the cai'iiiiial aililiictor iimi iliihictor iniiscuhu'
scars anil the imiiressions of the dental lamellne.
Wenlock limestone. England.

Genus MIMULUS, Barrande.

I'age '272.

MiMULUs WALDKONEN.SIS, Miller and Dyer.

Fig. 23. View from the l)rachial valve of a very young- indiviilual. The shell is nearly symmetrical, ami

shows an open triangular dellhyrium, ending in a circular apical foramen. X S.
Fig. 24. The opposite side of the same specimen. X 5.

(From Memoii-s N. Y. State Museum, Volume I, No. 1, i)late iii, tigs. 9, 9a.)
Fig. 2.1. Cardinal view of an adult individual, the type specimen. The cardinal area shows no trace of

deltidium or foramen. X •^.
Figs. 2G, 27, 28. Other views of the same specimen ; showing the peculiar asynunetry of thf shell.
Niagara group. Waldron. Indiana.

MiMULUS contrarius, BiiiTiinde,

Fig. 29. The exteiior of the jiedicle-viiU'e ; showing the broad median sinus.

Fig. 30. Cardinal view; showing the relative contour of the valves and the faint trace of the deltidium.
Etage Es. Tetiv, Bohemia.
(After Barrandb, Systeme Silurieu, Vol. V, pi. 9, tig. vi. A, k.)

MlMDLUS PERVERSUS, BiVlTJUlde.

Fig. 31. Dorsal view of the .shell; .showing the sinus on the brachial valve and the Mninlei'ru|iti'cl cardinal

area of the pedicle-valve.
Fig. 32. Cai'dinal view of the same specimen.

Etage E™. Listice, Bohemia.
(After Barrande, Systeme Silurien, Vol. V. jil. 1. tig. iii. <•. e.)

Genus STREPTIS, Davidson.

P.ige 274.

Streptis Grayi, Davidson.
Fig. 33. View of a brachial valve which retains the lamellar expansion at one of the growth-lines. X •!.
Etage Eo. Lodeaitz, Bohemia.

(After Bahra.vdk, Systeme Silurien, pi. S3, tig. ii, 3a.)
Figs. 34, 3.5. Brachial and anterior views ; showing the asymmetry of the valves, the concentric ornamenta-
tion and the perforated deltidium. X 5.
Fig. 36. Cardinal view of a similar specimen. X 4.

Fig. 37. The cardinal process, broken at its tip, jii'obably near the point of bifurcation.
Figs. 38, 39. Interiore of pedicle and brachial valves.

Wenlock limestone. Dudley, England.
(After Davidson, Bntish Silurian Brachiopoda, pi. xiii. tigs. l.ia, 176. 1B&, 21. 19. 20.)

PLATE XII.

(FiRUies 1-5, S-Jl Ijy K. f WHiiHELu, i>, 7 by F. B. Meek.)

Leg-end. H. Hing-e-liiic. b. Dental sockets.

ID. Deltidiuni, pedicle-valve. t. Teeth.

C. Deltidiuni, brachial valve. a. Antericir adductors.

a. Cardinal area, outer jiortioii. a'. Posterior adductor.'*,

j. Cardinal pi'oces-s. r. Diiluctors.

i. Lobes of cardinal (irncess.

Genus STROPHONELLA, Hall.

Papre 29U.

StROPHONELLA ( ) STRIATA, Hixll.

Fig. 1. The exterior of a brachial valve.

Fig-. 2. The interior of a j)edicle-valve ; showing the extension of the dental laraellffi along the sides of

the musoiilar area, and the crenulations of the cardinal margin near the delthyrium.
Fig. 3. An enlargement of the central portion of the brachial valve ; showing the cardinal area, its
crenulated margin, and the deltidiuni envelojiing the lower portion of tlie lolies of the cardinal
process. In this drawing the specimen is viewed with tlie cardinal area nearly at right angles
to the line of \ision ; the groove between the lobes of the cardinal process is, therefore, much
foreshortened, and made to appear shallow ; the cruial Hdges are also to be regarded as I'e-
ti'eating rapidly into the background.

Niagara group. lValdro7i., Indiana.

Stropiionella semifasciata, Hall.

Fig. 4. The exteiior of the concave pedicle-valve.

Fig. 5. An enlargement of the central portion of the area of both valves ; showing the development of

the deltidia and the obliipie striaj on the broad triangular .sjiace enclosed by tlie lines o, a. a.

[This space should be iletined by lines extending from the apex to the limit of the figure on

each side, and which may be obscure in some of the figures.]
Niagara gron]i. WaUlron. hidiana.

StROPHONELLA Leavenworthana, Hall.

Fig. 6. The exterioi' of a brachial valve.

Fig. 7. A profile of the same ; showing the concavity in eai-ly growth-stages, foUoweil by great convexity
and strong geniculation.

Fig. 8. The interioi- of the brachial valve ; showing the crenulations of the cai-dinal margin, the cardinal
process, slightly develojied crural plates, and the .adductor impressions.

Fig. 9. The interior of the pedicle-valve ; .showing the crenulations of the hinge-margin, tlie closed del-
thyrium, and the arrangement of the muscular scars.

Lower Helilerberg group. Albany county^ N. Y.

StROPHONELLA punctulifera, Coiirad.

Fig. 10. The exterior of the brachial valve; showing tlie concavity in the umbonal, and convexity in the
pallial region.

Fig. 11. An internal cast of a brachial valve; showing the muscular imprints ,ind the crenulations in the
matrix left by the removal of the hinge.

Fig. 12. The cardinal areas of both valves of fig. 10 ; showing the narrow convex deltidiuni closing the
delthyi-iuni in each valve. X 1^.

Lower Helderlierg group. Near ClarJrsvUle, N. T.

StROPHONELLA AMPLA, Htlll.

Fig. 13. An internal cast of a pedicle-valve; showing the muscular impressions and marks of the strongly
pustulose interior surface. In the imprint left by the cardinal area are seen the crenulations
of the hinge-line, and the mark of the .small, linear convex deltidium.
Scthoharie grit. Albany munty, N. Y.

Fig. 14. The interior of a pedicle-valve in which external evidence of the deltidiuni is lost and the crenula-
tions of the hinge extend more than half the length of the area. The margin of the area on
each side of the deltidium has been broken away by the detachment of the cardinal )iroi;e.ss of
the other valve.

Corniferous limestone. Owmdaga VaUry, N. Y.

Fig. l.'i. An enlargement of the surface sfriie.

•^ iii ^ 13 lu: :£ X) :f^ ss iej ^ .

Strophomenidae ,

Palaeoni. NY.Vol.lV.Pt ii ^

GcM\ciic Illii:slriition.'3

Plate M.

F..r .'/r^-:-:e.C..ae-

PLATE XII— Continucil.

Strophonella re versa, Hall.

Fig. 16. View from the lirai-hial valve; showing the iiiiinteirupteci ai-ea of the ))edio.le-valve.

Fig'. 17. The exterior of the pedicle-valve.

Fig. 18. The interior of a brachial valve ; showing the deeply bifurcated cardinal process and the muscu-
lar scars.

Fig. 19. The iiiterior of a pedicle-valve in which the muscular and viiscular m.arkings ai'e vei'y strong.
The cardinal area is seen to lie without any trace of deltidiuni, and the unibonal cavity has
been so completely tilled by calcareous depositions about the lobes of the cardinal proc-ess that
the latter have broken and remain attached (i. i,) to the pedicle-valve.

Fig. 2(1. The central portion of the hinge, enlarged, from .a specimen which has lieen somewhat weathei-ed,
thus exposing the vertical ridges which terminate in crenulations at the margin, anil .also show-
ing the limits of the deltidia. X 2.

Upjier Devonian. Roekford. Iowa.

Strophonella c^lata. ILiU.

(See Plate XVb, tig 10.)
Fig. 21. A cast of the interior of the pedicle-valve ; showing the widely extended, crenulated hinge-iine. and
the very concave valve with strong luuscular and vascular impressions. The points marked k,
are the tilling of the cavities beneath the area for receiving the extremities of the i-ardinal
process.

Chemung group. Near Elmira, N. Y.

i

PLATE XIII. j

(Figures 1-27 by It. P. VVHITFIELU; 28 by F. B. Meek, emend.i

Legend. II. Hinge-liiie. j. Caidiiial process.

U. Deltidinin. ^- Anterior adductors.

^. Delthyrium. , »'■ Posterior'adductors.

t. Teeth. I'. Anterior diductors.

b. Dental socket.«. '■'. Posterior diductors.

s. Median sejituni. o. Ovarian spaces.

Genus STEOPHEODONTA, Hall. i

P.ige 284. _ !

Stropheodonta (Brachypkion) profunda, Hull. I

(See Plate XX, figs. 29-31.) 1

Fig. 1. The internal cast of a pedicle-valve ; showing the muscular impiessions. :

Kig. 2. A partial cast of a pedicle-valve with the shell removed fr-om the upper portion ; showing the im- ,

pi-e.ssion of the nariow ai-ea. The margin of the valve (ireserves the shell with its characteris- '

tic sti'iie. I

Fig. :i. The central portion of a brachial valve, enlarged from a gutta-percha impiessioii. ]

Niagara limestone. Racine^ Wisconsin.
Fig. 4. The interior of a pedicle-valve having the delthyrium but partially closed, and showing the strong

crennlations of the cardinal margin near the delthyrium.

Fig. .">. An enlargement of the central portion of the area of the same specimen. X 2. ^

Niagara group. Waldron, Indiana. \

i

Stropheodonta (Brachyprion) varistriata, Coiimd.

Fig. tj. The exterior of the jiedicle-valve. \

Fig. 7. The interior of a similar valve. i

Fig. 8. An enlargement of a portion of the same specimen ; showing the breaking of the area by the de-
tachment of the cardinal pi'ocess of the opposite valve. X 3.

Fig. 9. An enlargement of the central part of the area of another specimen ; showing the char.acter of the
<leltidiuni and the short row of crennlations. X 3.

Fig. 10. An enlargement of the umbonal portion of a pedicle-valve; showing the character of the orna-
mentation. X 3.

Fig. 11. An enlargement of a portion of the interior of the jiediirle- valve ; showing the crennlations of the
hinge and the charactei' of the muscular impressions. X -.

Fig. 12. The cardinal process and crural plates. X 2.

Figs. 13, 1!). Enlargements of the surface stria>.

Fig. 14. The exterioi' of a pedicle-valve.

F\g. 16. An enlargement of one-half of a small pe<licle-valve ; showing the fasciculate stna>. '

Lower Helderberg grouji (Tentacnlite and Pentamerns limestones). SchofiarieCii., N. Y.

1

Stropheodonta varistriata, var. arata, Hall. , 1

Kig.s. 17, IS. Views of l\»o peilicle-valves ; showing the strongly fasciculate surface stria'. J

Lower Helderberg group. Becraft's Mountain, Hudson, N. Y. 1

Stropheodonta profunda ? ■

Figs. 19, 20. View.s of a .specimen which has heen referred, with doubt, to this species.
Clinton gi'onp. Niagara comity, N. Y.

Stropheodonta varistriata, CoiujkI (= ,Sf. /mpressa, Conrad). j

Figs. 21, 22. Two views <if this shell ; .slnivving the clepressed umbo and the great convexity in the pallial ■

region. " j

T^owcr Helderberg grouj). Eastern New Yorlc. ■ I

Palaeont . N.YV0I .IV. Pt ii

IB -Ji ^\ B lAl -J. D -J' U ILI ^

Strcphoinenictce.

(ii-ni'iu lUuslriilioii.-

PlateXI

>

R.P Whitfield. del.

.-VV ^

IMjATK Mil— Contlliucil.

Stropheodonta (LEPTOSTROrHiA) Becki, Hall.

Fig. 23. The interior of a pedicle-valve. The delthyriuiii is exposed l>y the reimival of the deltidimn, and
the short dental lamelUe have united, forming a minute pedicle-pit. The nuKscular area is
bounded laterally by divergent papillose ridges which take their origin at the extremities of
the dental lamella'.

Fig. 24. The exterior of a bi-achial valve; showing the concentric undulations.
Lower Helderberg group. Schtharie, N. Y.

Stropheodonta magniventra. Hall

figs. 25. 26. Natural casts of the interioi' of pedicle-valves ; showing the great development of the muscu-
lar areas

Oriskany sandstone. Albany county. N. Y.

Stropheodonta (Leptostkophia) magniitca, Hall.

Fig. 27. The interior of a brachial valve, drawn fi-om a gutta-percha impre.';sion ; .showing the character of
the cardinal process, which is foi'eshortened in the figure, the obsolescent dental sockets, the
crural plates and the muscular area.

Oi-iskany sandstone. Albany county. N. Y.
Fig. 28. The interior of a pedicle-valve ; showing the formation of a pedicle-pit in the delthyriuin, by the
union of the dental lamellie ; also the expanded, undetined muscular area.
Oriskany sandstone. Cumberland, Maryland.

Fig.

7.
8.

Fig.

Fig.

3.
If).

PLATE XIV.

(Figures 1-22 by R. P. Whitfield.)

Legend. D. Deltidiiim. a. Anterior adductors,

j. Cardinal j)ro<>es.s. a'. Posterior adductoi-s.

s. Sei>tuni. o. Ovarian spaces.

b. Dental sockets. v. Vascular sinuses,

r. r'. Di(iiictor scars.

Genus STROPIIf:ODONTA, Hall.

Page 284.
StKOPHEODONTA (DoUVILLINa) IN.EQUISTKIATA, Hilll.
Figs. 1. 2. 8. Tln-ee views, giving the external characters of the species.
Fig. 4. The interior of a brachial valve.
Fig. :"). The central portion of the interior of the brachial valve, enlarged to .show the liroail, flat posterioi-

muscular scars and the elevated anterior muscular ridges. X 3.
Fig. H. The interior of the pedicle-valve, enlarged to show the muscular impressions. X 2.
Hamilton group. Wester7i New York.

Stropheodonta demissa, Conrad.

The exteiior of a pedicle-valve ; showing the fasciculate character of the surface stria; near the beak.
A view from the brachial valve of .a larger individual ; showing no evidence of deltidium on the

striated cardinal area of the pedicle-valve.
A profile view of the same.

An enlargement of the cardinal areas ; showing the vertical striie and complete obsolescence of
the deltidia. X I5.
Fig. 11. The interior of a brachial valve ; .showing the crenulated hinge-margin, the cardinal process and

muscular imjn'essions.
Fig. 12. The interior of a pedicle-valve ; showing the muscular impressions. The center of the area has
been broken away by the detachment of the cardinal process.
Hamilton group. Wester7i New York.

Stropheodonta in^quiradiata, Hall.

Fig. )'S. An intei-nal cast of the pedicle-valve ; showing the muscular impressions and vascular sinuses.
Fig. 14. An enlargement of the umhonal portion of another cast ; showing the dendritic <iiductor scars, the
atiductoi's, and, at k, the tilling of the cavities occupied by the branches of the cardinal process.
Corniferous limestone. Neio York.

Stropheodonta Patersoni. Hall.

Fig. 15. The extei-ior of a pedicle-valve ; showing, over the visceral i-egion. the inidulations of the surface
between the primary I'adii.

Corniferous limestone. Western New York.

Stropheodonta concava, Hall.

Figs. 1(5. 17. Two views, to show the general external character of the shell.

Fig. 18. The umbonal portion of the interior of a brachial valve. From a young individual in which the
cardinal process is comparatively slender and the muscular area but slightly thickened. X l^.
Hamilton group. York, N. Y.

Fig. 13. The interioi' of the brachial valve ; showing the characters of the fidl-gi'own individual.

Fig. 20. The central cardinal portion of the brachial valve of a mature individual. The lobes of the car-
dinal ])rocess are of great size and deeply grooved, the crural jilati^s in a i-ndimentary condition
and the muvscular scars much thickened. X 2.

Fig. 21. A postei-ior view of the same specimen ; showing the crenulated edges of the cardinal lobes and
the .size of the <:rural plates. At x the base of the cardinal process has been excavated for the
reception of the mai-gin of the pedicle-valve. X 2.
Hamilton grouj). Canaiidair/ua Lake, N. Y.

big. 22. The interioi' of a j)edicle-valve ; showing a slight trace of the deltidium.

Fig. 23. An internal cast of the pedicle-valve ; showing the adductor and diiluctor seal's.
Hamilton group. Western New York.

m Lli ^ £ :ii It S 3^ D Jnj J\,

StrophoiTieiTid^

PalaBont.N.YVoMV.Ptii.

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Plate X!V'

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Wtiitiield.del.

PLATE XV.

(Figures 1-36 by R. P. WHITFIELD.)

Legenii, v. Pedicle-valve. j. Ctiiilinal process,

d. Brachial valve. c. Ci-uva.

A. Cardinal area. s. Median septum.

D. Deltidiuni. r. Diductor scai-s.

A. Delthyrium. a. Anterior adductors.

t. Teeth. a'. Po.sterior adductors,

b. Dental sockets.

Genus STROPHEODONTA, Hall.

Page 284.

Stropheodonta corrugata, Conrad.

Vig. 1. The exteiior of a pedicle-valve ; showing the corrugations along the car<linal margin.
Clinton gi'oup. Western JS'tw York.

Stropheodonta (Leptostrophia) perplana, Conrad.

View of the tirachial valve ; showing the cardinal area of the opjiosite valve.
Corniferous limestone. Western New Yorli.
3. The peiiicle-valve of a smaller specimen.

Hamilton group. Western New York.
The exterior of a pedicle-valve ; showing the alternation in size of the stris.
An enlargement of the striae from the same specimen.

Hamilton group. NeiD Buffalo. Iowa.
A similar enlargement where the stri;e are of equal size.

The interior of a pedicle-valve ; .showing the uninterruijted cardinal area and the thickened pus-
tulose lateral margins of the muscular ai'ea.

Hamilton gi-oup. Westerti New York.
The interior of a pedicle-valve retaining similar characters.

Hamilton group. New Buffalo, Iowa.
An enlargement of the interior umbonal portion of the brachial valve ; showing the cardinal pro-
cess and latei-al niusculai- ridges. X -.

Hamilton group. Canandaigu,a Lake. N. Y.
Fig. 10. The cardinal process, enlarged to show the grooving of the posterior surface of the lobes foi- the

attachment of the diductor mu.scles. X 3.
Fig. 11. The cardinal areas of both valves; showing the unintei-rupted striated surface. X 14-
Fig. 12. A longifuiiinal axial section of the two valves ; showing the normal curvatui-e of the shell and the

position of the cardinal process.
Fig. 13. An enlargement of the surface as left by the removal of the shell.
Hamilton group. Western New York.

Stropheodonta perplana, Conrad, var. nervosa, Hall.

Fig. 14. A poi-tion of a pedicle-valve; showing the irregular character of the stria".
Fig. 15. An enlargement of a portion of the same.

Fig. 17. A specimen showing the wrinkled striae and extended cardinal angles.
Chemung group. Steuben county, N. Y.

Stropheodonta (Leptostrophia) Junia, Hall.

Fig. IB. A portion of the pedicle-valve ; showing the crenulated area and partially covered delthyrium.
Hamilton group. Canandaigua Lake, N. Y.

Stropheodonta (Douvillina) Cayuta, Hall.

Fig. 18. An internal cast of the pedicle-valve ; showing the short, transverse, shar|)ly defined muscular

scar.
Fig. 19. An enlai-gement of the muscular area of the same specimen. X 2.
Chemung group. Steubeti county, N. Y.

Fig.

0

Fig.

3.

Fig.
Fig.

4.

5.

Fig.
Fig.

6.

7.

Fig.

S.

Fig.

9.

Fig.

2.T

Fig.

26

Fig.

27

PLATE XV— ContinneU.

Stropheodonta (Pholidostrophia) nacrea, Hall.

Figs. 20, 21. 22. .Three views giving the general external characters of Ihe species.

Fig. 23. The interior of a brachial valve ; showing the crenulated hinge-margin, cardinal process and

nins<:nlar inii)ressions.
Fig. 24. The inteiior of the pedicle-valve ; showing the nmscular impi'essions and partially closed delthy-

rium.

Hamilton group. Western New York.

Genus PLECTAMBONITES. Pander.

(See Plate XV.\.)
Page 295.

Plectambonites sericea, Sowciby.

View of the brachial valve ; showing the eai-dinal area and deltidiinn of the opposite valve.
The exterior of a pedicle-valve in which the striae alternate in size.

The interior of the brachial valve ; showing the depresseil visceral disk, the muscular scai's and
cardinal process.

Fig. 28. An enlargement of the cardinal process ; showing its union with the crural plates and the abrupt
tei'mination of the latter. The process is simple, but on its pcjsterior face appears trilobed fi'om
coalescence with the ends of the crural plates. X 3.
Fig. 29. The interior of the pedicle-valve ; showing the divergent muscular scars.
Trenton horizon, mineral Point, Wiscoitsin.

Genus LEPT^NISCA, Beecher.

Page 300.

Lept^nisca concava, HiiU.

Fig. 30. The extei'ior of a jiedicle-valve ; showing the scar at the beak, due to the attachment of the shell.
Fig. 31. The interior of the same specimen ; showing the deltidiuni, the strong dental lamellae and the
median septum. X 2.

Lower Helderberg group. Near Clarksville, N. Y.

Genus CHRISTIANIA, gen. nov.

Page 298.

Christiania subquadrata, H;ill.

Fig. 32. Tlie intei-ioi- of a bi-acliial valve; showing the bilobed cardinal process and the quadruple ad-
ductor scar, divided by high, vertical muscular walls.

Fig. 33. The inteiior of the pedicle-valve, with an open delthyrium, and showing the muscular walls and
scars.

Lower Helderberg horizon. Fei'ry comity. Tennessee.

Genus PLECTAMBONITES, Pander.

Page 295.
ipLECTAMBONITES TRANSVERSALIS, Dllllliail.
Fig. 34. The exterior of a pedicle-valve. X 2.
Fig. 35. A view from the opposite valve. X 2.

Fig. 36. The interior of a bi-achial valve ; showing the elongate adductor scai-s. X 2.
Niagara group. Lockport, N. Y.

'B :ii Jt^ S -M 'J. 'D -J" IJLD^.

PalaBonl. N.YYol.lV.Pt ii

(ifiuM'U- Illustration."-

PlateXV

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PLATE XV A.

(Figures 1-lS, 20-2:

, -24-28, M, 40, 43 by E. Emmons; 19, '23, 34, 35, 37, 38 bv G. B. Simpson; 29, 30 bv J. M. Clarke; 41, 42
by C. E, Beecher; 31-33 copies.)

Legend.

D.
C.
ps.
F.

t.

a.
1.

Deltidiiim (pedide-valve).

Deltidium (brachial valve).

Pedicle-.sheath.

Koranieii

Teeth.

Dental lamellae.

Spondyliuni.

j. Cardinal process.

c. Crura,

br. Brachial ridijes.

a. Anterior adductor scars,

a'. Posterior adductor scars.

r. Diductor seal's.

X. Scar'of attachment.

Genus CLITAMBONITES, Pander.

Clitambonites Verneuili. (voii

(See Plate VII.)
rage 233.

Eiclnvald) Billiuff.s (== Hemipronilen Americannx,
Whitfield).

Figure 2 shows that the deltidium has been lost, exposing

showing the concave delthy-

Figs. 1, 2. Opposite sides of conjoined valves.

the spondyllum.
Fig. 3. The interior of a pedicle-valve which does not retain the deltidium ;

rial plate or spondyliuni supported by a median septum.
Fig. 4. A view of the same specimen, looking into the umbonal ca%-ity of the valve.

Trenton horizon. Cannon Falls, Minnesota.
Figs. 5, R. Interiors of brachial valves; showing the simple cardinal process abutting against the deltidium,
and the quadripartite impression of the adductor muscles.
Trenton horizon. Island of Anticosti.
Figs. 7. 8. Profile and cardinal views of a small pyramidal specimen which may be a variety of this spe-
cies. The deltidia of both valves are retained, that of the pedi<'le-valve being perforated by a
large foramen.

Trenton horizon. Cannon Falls, Minnesota.

Fig.

Genus HIPPARIONYX, Vanuxem.

(See Plate IX.)
Page -257.

HiPPARiONYX PROXiMUS, Vauuxeiii.
The interior of a pedicle-valve di'awn from a gutta-percha impression of a natural mould ; show-

ing the character of the cardinal area and dental lamelLne. the gr'eat size of diductor scars, the
margins of which are thickened ami elevated by the deposition of testaceous matter. The
surface of the elevations thus formed is strongly pitted. The specimen also shows the low
median septum diviiling the adductor impression." which in the umbonal region unites with the
dental lamelUe to foi'm an apical callosity.
Fig. 10. The cardinal process and crural jilates of the brachial valve. The ci'enulations of the marfrin of
the valve are seen to extend almost to the base of the process.
Oi'iskany sandstone. Albany county. iV. T.
Fig. 11. Profile of an internal cast of the two valves. The specimen is drawn with the brachial valve above
and shows the relative convexity of the v.alves and the extent of the crenulated margin toward
the apices.

Oriskany sandstone. Cayuga, Province of Ontario.
For further illustr.ation, see Palieontology of New York, Volume III, plates 89, 90.

Genu'^ LEPTELLA, gen. nov.

Page 293.

Leptella sordida, Billings (sp.).

Figs. 12, 13. Two views cf a specimen retaining Vioth valves, and showing the outline, contour and general
external characters of the species." The delthyrium of the pedicle-valve is partially closed by
a convex delliilium. X '^,
14. The interior of a pedicle-valve ; showing the cardinal area, deltidium and teeth, but no trace of
the muscular scars is retained. X 3.

Fig.

Fig. 16.

PLATE XV'A— Coatinaed.
Fi" 15 The iiitei-ior of a brachial valve. The cardinal pi'ocess consists of two indejiendent apophyses,
" "' not coalesced with the cniral plates, the latter being depressed at their origin but considerably
elevated at thfii' extremities. The visceral region is concave on either side of a broad median
riiige and its surface radially sti'iated ; from its anterior margin the surface of the valve is
abruiitly and evenly deflected. X 5.
Cardinal view of the same specimen ; showing the wiilth of the area, the postenor face of the car-
dinal process and the elevation of the crural ])Iates. X ».
These figures are from the original specimens of the species.

"Point Levis; in the upper part of the Limestone No. 2, Quebec group." (Billings.)

Genus ANOPLIA, gen. nov.

(See Plate XX.)
Page 309.

Anoplia nucleata, Hall.

Fig. 17. Cardinal view of an internal cast of the pedicle-valve, retaining the impiessions of the extremely
olili(|ue dental lamelte and the short median septum ; also showing the indistinct outline of the
muscular area. X 3.
Fig. IS. The interior of the brachial valve which has a close similarity to that of Chonetes. X 2.
Oriskany sandstone. Albany comity, N. T.
See al.so the illusti-ations in Palseontology of New York, Volume III, plate 91, figs. 1 a-d.

Genus LEPT.^NISCA, Beecher.

Page 300.
LEPT.ffiNISCA CONCAVA, HuU.

(See Plate XV, figs. 30, 31.)
Fig. 19. The exterior of a pedicle-valve ; showing the contour and character of the surface. X 2.
Fig. 20. The interior of a brachial valve, somewhat imperfect about the margins and cardinal jn-ocess,

but showing the spii-al lirachial ridges and the thin median septum. X 2.
Fig. 21. Cardinal view of an imperfect bi-achial valve presei-ving the character of the cardinal process,
which is deeply quadrilobate. X 3.
Figures 20 and 21 are from specimens illustrated by Mr. Bekcher.
Lower Helderberg group. Near Clarksville, N. Y.

Leptjenisca adnascens, sp. nov.

Fig. 22. A j)edicle-valve attached by nearly its entire outer surface to the interior of a valve of Orthis
oblata. The specimen shows the dental lamella; and median ridge dividing the muscular ai-ea.
X 3.

Fig. 23. A specimen retaining both valves, attached to Orthis perelegans. X 4.
Lower Helderberg group. Near Clarksville, N. T.

Leptjsnisca tangens, sp. nov.

Fig. 24. The exterior of a pedicle-valve with the umbo flattened from attachment, and showing the low

median .sinus. X 2.
Fig. 25. The interior of the same specimen ; showing the cicatrix of attachment (x), the deltidiuni and the

dental lamella' X 2.
Fig. 2ti. The exteiioi- of a pedicle-valve in which the rugose growth has obscured the median sinus. The

deep umbonal depression has been caused by attachment to some bryozoan. X 3.
Figs. 27, 28. Opposite sides of a pedicle-valve attached to a twig of Trematopora. X 3.
Figs. 29, 30. Opposite sides of a similar valve which has been attached to a fi'ond of Fenbstella. X 3.

The.se la-st two specimens show the bilobate exterioi-, the deltidium, teeth, strong dental lamellae

liroduced about the muscular area, and the short median septum.
Lower Helihu-berg group. Near ClarkstHlle, N. Y.

113 m ^ -s Mil m ':f m id ^

Strophomeiadao. etc.

D .]..,nnt.N Y.Vol.rV.Pl i'^Vo; Viil.

* 'I'MITU lllllsllMluni'

Plate XV. A

E. Emmons del

Pha.Astiuh.

I'LATE XVa— Conlinuerl.

Genus DAVIDSONIA, Bouchard.

rase 301.

Davidsonia Verneuiliana, Bouchard.

Fig. 31. Profile of an attacheii specimen retaining tlie two valves.

Figs. 32, 33. Interiors of the brachial and pedicle-valves respectively. After Davidso.n.

Genus PLECTAMBONITES, Paxder.

(See Plate XV.)
Page 295.

Plectambonites plicatella, Ulrieh.
Fig. 34. A g-ronp of these shells which have fallen into the sediment with their valves attached and open.
Fig. 35. One of the shells, enlarged. ITie surface exposed is the exterior, the concave or brachial valve
showing, fi-oni comjiression, the outline of the cardinal process. X !>.
Hudson River g-roiiji. Covrington, Kentucky.

Genus CHRISTIANIA, gen. nov.

Page 298.

Christiania subquadrata, Hall.
(See Plate XV, figs. 32, 33.)
Fig. 36. Cardinal view of the brachial valve ; showing the bilobed cardinal process, widely divergent
crural plates, the prominent longitudinal and transvei-se musculai- ridges enclosing' the impres-
sion of the adductor muscles. X 3.

Lower Helderberg group. Perry county. Tennessee.

Genus RAFINESQUINA, gen. nov.

(See Plate VIII.)
Page 2SI.

Rafinesquina Ulrichi, James.

Figs. 37, 3S. The exterior of two mature pedicle-valves in wiiich the 'primitive condition of the pedicle-
passage as a tube or sheath is i-etained. This appeai-s to be a normal feature of matunty in
this species. X 2.

Hudson River group. Covington, Kentucky.

Rafinesquina unicostata. Meek and Woiliieii.

Fig. 39. The interior of a brachial valve; showing the canlinal process, dental sockets and nuiscular area.
Hudson River group. Sprbig Valley. Minnesota.

Genus LEPT.ENA, Dalman.

Page 276.

LEPT^ffiNA RHOMBOIDALIS, WilckcilS.

(See Plate VIII. figs. 17-31; Plate XX, figs. 21-2ii.)

Fig. 40. The centi-al cardinal portion of a mature pedicle-valve ; showing the position of the inner ojiening

of the foramen. A bristle has been drawm through the foramen to show that the passage was

open at maturity. X 3.

Lowei- Helderberg group. Near Clarkvsille, iV. F.
Figs. 41. 42. Two views of the younge.st specimen obtained; much enlarged to .show the structure of the
pedicle-passage in its earliest observed condition. X 10. After Beecher and Clarke.
Niagara group. Waldro7i. Indiana.

LEPT.ffiNA RHOMBOIDALIS, Var. VENTRICOSA, Hall.

Fig. 43. The interior of a pedicle-valve ; showing the gj-eat prominence of the nuiscnlar ridges about the
diiluctor seal's and the thickened central adductor impression.
Oriskany sandstone. Cumberland, Maryland.

PLATE XVb.

(Figures 1-9, 14-19, 21, '.'i.as-SO, 32-35 by G. B. Simpson; 10-13,21-26, 36, 37 by R. P.Whitfield; 20,23,27, 31 by E. Emmons.)

Legend, j. Ciinlinal process. r. Diductor scai-s.

a. Adductor scars.

Genus STEOPHEODONTA, Hall.

(See Plates XIII, XIV, XV, XX.)
Page 284.

Stropheodonta (Douvillina) arcuata, Hall.

F\g. 1. The interior of a i:ieilicle- valve ; .showing the cavity in the cardinal area as left by the removal of
the cardinal proce.ss, the thickened, sharply defined and elevated muscular area.

Kijf. 2. The interior of the brachial valve.

Fig. 3. The same enlai'ged, to show the character of the cardinal process, the small crural plates and
divergent musculnr ridges. X 2.

Upper Devonian, Lime Creek, Iowa.

Stropheodonta variabilis, Calvin.
Figs. 4, 5. Opposite sides of the same specimen ; showing the contoui- and surface ornamentation. X 2.
Fig. 6. The interior of the brachial valve ; showing the cardinal process and divergent muscular ridges.
X 2.

Upper Devonian. Lime Creek, luwa.

Stropheodonta (Douvillina) Cayuta, Hall.

Fig. 7. The interior of a pedicle-valve ; showing the sharply defined, thickened and elevated muscular

area and its subdivisions.
Fig. 8. The intei-ioi' of a brachial valve ; showing the muscular ridges.
Chemung group. Tioga county. Pennsylvania.

Strophkooonta (Douvillina ?) iN.a5QuiSTRiATA, Hall.

Fig. 9. The interior of a pedicle-valve ; showing the greatly thickened lateral margins of the muscular im-
pression

Hamilton group. Canandaigua Lake, N. Y.

Genus STROPHONELLA, Hall.

(See Plate XII.)
Page 290.

Strophonella c^lata, Hall.

Fig. '10, The intei'ior of a brachial valve in an unusually fine state of jire.servation. The flabellate muscular
scars have the form usual to this genus and .similar to (hat chai-acterizing Douvillina. The
crenulations of the hinge-line do not extend to the extremities of the cardinal area ; a feature of
fi'equent occurrence in many of the earlier species of Stropheodonta. The impressions of the
pallial sinu.ses are also distinctly shown.

Chemung group. Near Addison, N. Y.

Genus CHONETES, Fi.scher de Waldheim.

(See Plate XVI.)
Page 303.

Chonetes Flemingi, Norwood and Pratteu.

Fig. 11. The interi-r of a pedicle-valve ; showing the character of the muscular scars and the internal
opening.s of the sjiine-tutjes beneath the cardinal area. X 3.
Coal Mea.sures. Illinois.

Chonetes Smithi, Norwood and Piatten.
I'"ig. 12. The interior of a brachial valve ; showing the four scars of the adductor muscles. X 2.
Coal Measures. IlUnois.

PLATE XVb— Continued.

Chonetes Amazonica, Derby.

Fig. 13. An enlargement of an internal cast of the jieilicle- valve, which retains* the filling of the spine-tubes
crossing the cavity left by the removal of the cardinal portion of the valve. X 3.
Coal Measures. Rio Tapajos, Brazil.

Genus CHONOSTKOPHIA, oex. nov.

(See Plate XVI.)
Page 310.

Chonostrophia Heldekbekoia, sp. IIOV.

Fig. 14. A specimen in whiih Ihe valves are openeil, exposing llieir internal suitace.-i. The shell may have
been somewhat flattened in fossilization, but still shows the reversal of the relative convexity of
the valves, the oai-dinal ai-ea, teeth and faint median septum of the pedicle-valve and the linely
lineate surface. The cardinal process is not retained with sufficient distinctness to permit its
accurate delineation.

Lower Helderberg group. Near Clarksville, N. F.

Chonostrophia reveksa, Whitfield.

Fig. 15. The exterior of a pedicle-valve ; showing its gentle concavity and fasciculate ornamentalic n. X -.

Cornifei-ous limestone. Delaware, Ohio.
Fig. 16. The exterior of a pedicle-valve which retains the cai'dinal spines. X '2-

Fig. 17. The interioi' of a brachial valve ; showing the contour of the shell ami retaining the caniinal pro-
cess. X 2.

Upper Helderberg group. Cayuga, Ontario.
Fig. 18. An enlargement of the cardinal process and crural plates. The foi-mer is bilobed but shoi t, and
terminates abruptly at the base. The crural jjlates are also quite short and have a slightly sin-
uous curvature. X 6.
Fig. 19. An enlargement of the surface striae; showing their fasciculate grouping. X tJ.
Cornifeions limestone. Delaware, Ohio.

Genus CHONOPECTUS, gen. nov.

(See Plate XVI.)
Page 31-2.

Chonopeotus Fisgheri, Noi-vvoud and Pnitteii.

Fig. 20. The exterior of a pedicle-valve which retains the reticulate surface ornamentation and a large scar
of attachment. X 2.

In strata referred to the age of the Waverly group. Warren, Peniisylvania.

Pig. 21. A_!pedicle-valve having the normal pi-oportions of the species, and showing a few spine-bases on
the cardinal margin The retii.'ulate surface markings, as on this specimen, do not usually ex-
tend over the pallial region, which is covered by exceedingly fine, often irregular radiating
striae.

Fig. 22. Posterior view of the umbonal region in the same .specimen, enlarged to show character of the
cicatnx. X 2.

Fig. 23. A small pedicle-valve, i-etaining the cardinal spines and showing, over the body of the shell, some
divergent impressions which may be of vascular origin.
Yellow sandstones. Burlington, Iowa.

Genus STROPHALOSIA, King.

(See Plates XVI, XVII, XVI1.\.)
Page 314.
Strophalosia TRUNCATA, Htlll.
Fig. 24. An internal cast of a pedicle-valve ; showing the muscular impressions ; enlarged.
Fig.J 25. The interior of a pedicle-valve ; enlarged.

Fig. 26. The exterior of a pedicle-valve ; showing the spiniferous surface ; enlarged.
Marcellus shales. New York.

PLATE XVb— Continued.

Strophalosia radicans, Wiiichell.

Fig. 27. A peiliele-valve, attached by its entire outer surface ami spines U> a Fistdlipuba. X 2.

Fig. 28. A pedicle-valve, situated in a cavity among the ))olypite8ot .<4ce)-()«?aWa i>aTOrfso7ji. There is a slight
attachment by the apex of the valve, but fixation is mainly effected by the spines, those on the
cai'dinal margin ci-eeping along the surface of a polypile, and several of those which are on the
body of the valve crossing the cavity, their extremities being somewhat obscured liy the matrix
of the specimen. These latter spines appear to increase slightly in iliameter from the surface
of the shell outward, and their surface is marked with fine concentric annulations. X 3.

Fig. 29. The calyx of a single polypite of Acervularia Davidsonl, to which is attached a pedicle-valve of
this species ; its adherent spines lunning between the septa of the coral. X 3.

Fig. 30. An attached specimen, which retains the concave brachial valve in position, and shows the cardinal
ai-eas and deltidia of both valves. X 3.

Hamilton group. Little Traverse Bay, Michigan.

Strophalosia hystricula, Hall.

(See Plate XVII, figs. 29, 30.)
Fig. 31. An infei-nal cast of a peilicle-valve, which shows the scar of attachment and iniiiressions of the
bases of spines over the body of the shell. X 3.
Chemung group. Coneioango, N. Y.

Strophalosia scintilla, Beecher.

Fig. 32. A specimen retaining both valves, attached to the surface of ySpM'i/er Maricmensis. This specimen

shows no trace of spines. X 6.
Fig. 33. Another specimen which retains both valves, attached to a brachial valve of ProducteUa pyxidata.

The spines about the margin should have been represented as belonging to the lower, not to

the upper (brachial) valve. X 6.
Fig. 34. The interioi- of a pedicle-valve attached to the surface of Synngothyris Hannibaleiisis ; showing the

few short spines which characterize the species. X 4.
Choteau limestone. Pike county. Missouri.'

Strophalosia, sp. ?

Fig. 35. A Very small specimen attached to Spirifer Marione^isis. This specimen is peculiar in showing
spines on the surface of the brachial valve. It occurs in aseociat'on with S. .icintilla, and it
may possibly prove the young of that species. X 8.

Strophalosia Cornelliana, Derby.

Fig. 36. Posterior p.^rtion of the interior of the pedicle-valve ; showing the area, deltidiuni, teeth and mus-
cular scars. X 3.

Fig. 37. The intei'ior of an imjierfect brachial valve which retains the cardinal process, and shows the
muscular scars and brachial impressions. X 3.
Coal Measures. Bomjardim, Brazil.

m m -^ -^ mE s :f 'D m j^ .

Stropnor.iwnidau and ProdiicUdse .

Pala?onl.N Y.Vol !VP- ii-VoLVffl-

("'i'H»»rn' llliislr.iUon^i

Plate XV B

G.B. Simpson del

Asrat:^

PLATE XVI.

(Figures 1-16, 18-22, 24-30, 34-44 by K. I'. WiiitfikM) ; 17, ;il by F. H Mkkic ; 23 copy.)

Le'jenil.

Fi"

Fig.

Fig.
Fig.

D. Delti<iium, peiiic.le-valve.
C. Deltidium, brachial valve.
St. Cardinal tubes.
t. Teeth.

b. Dental sockets.
8. Septum.

j. Canlinal procesis.

a. Anterior adductors,
a'. Posterior adductors.

r. Anterior diductors.
r'. Posterior diductora.

V. Brachial ridges.

Genus CHONETES, Fischek dk Waldheim.

(See Plate XVu.)
Page 303.

Chonetes corxuta,

Hall.

1. A view of the pedicle-valve. X 2.

Clinton group. SotUis Bay, N. Y.

Chonetes setigeka. ll.ill.

2. A view of the pedicle-valve. X 2.

Waverly gi-oup. Penfield, Ohio.
5. Pedicle-valve of a larger siieciiuen with finer stris. X 2.
19. An enlargement of the surface striffi of this specimen.
Marcellus shales. Near Caledonia, N. T.

Chonetes scitula, Hall.

(?)Fig. 3. A pedicle-valve, with somewhat moi-e cii-cular outline and longei- car<linal spines than usual. X 2.

Fig. 4. A view of the brachial valve ; showing the cai-dinal area and deltidium.

Fig. 27. The interior of a brachial valve ; showing the structure of the cardinal process and the taint

brachial ridges. X 2.
Fig. 32. The interior of the pedicle-valve ; showing the cardinal area and teeth. X 2.

Hamilton group. Canandaigua Lake. N. Y.
Fig. 40. An enlargement of the cardinal portion of the valves; showing the hollow .spines and the curving
course of the spine-tubes through the substance of the cardinal area of the jiedicle-valve. X 8.
Hamilton gi'oup. Western New York.
Fig. 44. An internal ca.st of the pedicle-valve, retaining thi; tilling of the spine-tubes and showing their
convergence toward the beak before reaching the upper niai-gin of the area. X 8.
Chemung group. Cattaraugus county, N. Y.

Chonetes mucronata. Hall.

Fig. 6. A pedicle-valve with very coarse plications and apparently destitute of spines. X 2.
Fig. 7. A pedicle- valve with long, extremely divei-gent spines. X 2.
Marcellus shales. West Avon, N. Y.

Chonetes acutiradiata, Hall.

Fig. 8. The pedicle-valve.

Corniferous limestone. fVilliamsvUle, N. Y.

Chonetes Logaxi, Noiwood and Pratteii, vav. Aukoi;a. Hall.

Fig. 9. Pedicle-valve, enlarged to show the fine concentric striae. X 3.
Fig. 18. An enlargement of the surface.

Tnlly limestone. TidJy. N. Y.

PLATE SVI— Continued.

Chonetes coeonata, Conrad.

Fiy. 10. A view of the lii-achial valve j showing' the cardinal ai-ea ami deltiiiiinn.
Fig-. 11. A pedicle-valve with unusually strong' concenti-ic growth-lines.

Hamilton group. Daneii, N. F.
Fig. 24. The interior of a brachial valve ; showing the cardinal process, muscular scars and brachial
i-idges.

Hamilton group. York, N. Y.
Fig. 26. The interior of another brachial valve ; showing moi'e distinctly the quadripartite character of the

cardinal process.
Fig. 33! The interior of a pedicle-valve ; showing the cardinal area, teeth and muscular scars.

Hamilton group. Western New York.

Genus STROPHALOSIA, King.

(See Plates XVb, XVII, XVIIa.)
Page 3U.

Strophalosia muricata, Hall.

Fig. 12. The exterior of the pedicle-valve, from a gutta-percha impression of a natural mould ; showing the

short spines on the surface.
Fig. 16. Two views of a pedicle- valve ; showing the cicatrix of attachment.
Fig. 30. The interior of a bi-achial valve, from a gutta-percha impi'ession ; showing the cardinal process,

bi-achial ridges and median septum.
Fig. 38. An internal cast of the pedicle-valve ; showing the muscular impressions.

Fig. 42. An enlargement of the muscular scars restored from several internal casts of the pedicle-valve.
Chemung group. Meadville, Pennsylvania.

Genus CHONOSTROPHIA, gen. nov.

^(See Plate XVb.)
Page 310.

Chonostrophia complanata, Hall.

Fig. 13. The intei'ior of the pedicle-valve tVom a gutta-percha impression ; showing the reversed convexity

of the shell, the flabellate muscular area, conspicuous median septum, and the cardinal spines.
Fig. 29. Another interior of a similar valve in which the cardinal spines are apparently absent.
Oriskany sandstone. Albany county, N. Y.

Genus CHONETES, Fischer de Waldheim.

Page 303.

Chonetes hemisph^erica, Hall.

Fig. 14. A view of the pedicle-valve ; showing its great convexity.
Schoharie grit. Albany county, N. Y.

Chonetes arcuata, Hall.

Fig. 15. Profile of a pedicle-valve, from which the radiating striie have been accidentally omitted in litho-

gi'aphing.
Figs. 35, 36. Two views of an internal cast of the pedicle-valve ; showing the muscular impressions and the

crenulation of the cardinal area, caused tjy the casts of the spine-tubes.
Corniferous limestone. Near Williamsville, N. Y.

Genus CHONOPECTUS, gen. nov.

(See Plate XVb.)
Page 312.

Chonopectus Fischeri, Norwood and Pratten.

Fig. 17. The extei'ior of a pedicle-valve ; showing the concentrii^ally reticulate sui'lace.
Fig. 31. An enlargement of the surface ; showing the double series of conceutiic wiinkles crossing the fine
radiating strije.

Yellow sandstones. Burlington, Iowa.

if^ ipi ^x r; i£i; -ir D 3^ s -jj _a

Palaeom.Ny.VolIV.Ptii

(Jcnt'lic Jlllltillillloll.-:

Plate m.

R.PWhitead.del.

PhiLAil.hth

PLATE XVI— Continued.

Genus CHONETES, Fischer ok AValdiieim.

Page 303.

Chonetes Verneuiliana, Norwood and Pratteu.

Figs. 20, 21. Two views ; showing- the strong' median constriction. X '-.
Coal Measures. Illinois.

Chonetes mesoloba, Norwood and Pnitten.
Fig. 22. A pedicle-valve ; showing the median fold. X 2.
Coal Measures. lUhiois.

Chonetes concentrica, de Koniuck.

Fig. 23. A species in which the surface is covered with strong concenti-ic wrinkles. This species may not
prove congeneric with Chonetes striatella, Dalman.

Lower Carboniferous limestone. Vise, Belgium.

Chonetes Logani, Norwood and Pratteu.

Fig. 25. The interior of a brachial valve ; showing the brachial ridges. Drawn from a gutta-percha im-
pression. X 2.

Waverly group. Wayne county, Ohio.
See Part ii, Volume VIII, for further illustration.

Chonetes defxecta, Hall.

Fig. 28. The interioi- of a brachial valve. X 2.

Hamilton group. Western New York.

Chonetes lineata, Conrad.

Fig. 34. The interior of a pedicle-valve ; showing the area, teeth and muscular impressions. X 2.
Corniferous limestone. Western New York.

Chonetes syrtalis, Conrad ( = C coronala, Conrad).

Fig. 39. An internal cast of the brachial valve ; showing the brachial ridges.

Fig. 41. An internal cast of the pedicle-valve.

Fig. 43. An impression of the exterior of a large shell.

Hamilton group. Eastern New York.

Genus STROPHEODONTA, Hall.

(See Plates XIII, XIV, XV, XVb, XX.)
Page -.'St.

Stropheodonta callosa, Hall.

Fig. 37. An enlarged cardinal view of the pedicle-valve ; showing the muscular impressions and crenula-
tions of the area.

Schoharie grit. Near Clarksville, N. Y.

i

i
PLATE XVII.

(Figures 1-15, 18-29, 33-46 by B. P. Whitfield; 16, 31, 3.! by F. B. Meek; 47-51 copies.)

Legoiui. A. Cardinal area. j. Cardinal process. I

D. Deltidiiun, pedicle-valve. v. Brachial ridges.

C. Deltidium, brachial valve. a. Anterior adductors,

t. Teeth. a'. Posterior adductor.s.

b. Dental sockets. r. Diductors.

Genus PRODUCTELLA, Hall. j

Page 328.

Pkoductella subaculeata, (Murchibou) Hall.

Fig. 1. The exterior of a pedicle-valve.

Corniferous limestone. Falls of the Ohio.
Fig. 2. The interior of a brachial valve ; showing the cardinal process. •'

Corniferous limestone. East Victor, iV. Y.

Productella spinulicosta, Hall.

Figs. 3, 5. Two views of a jiedicle- valve.

Corniferous limestone. Louisville, Kentucky.
Fig. -4. The exterior of a pedicle-valve.

Marcellus shales. Western New York. ,

Fig. 6. A pedicle-valve referred with doubt to this species. '

Yellow sandstones. Burlington, Iowa. \

Productella Shumardiana, Hall. i

Fig. 7. A pedicle-valve with distinct spinferous costal. This figure is from one of the original specimens ]

of the species. i

Yellow sandstones. Burlington, loiva.

Productella navicella, Hall.

Figs. 8, 9. Views of the interior and exterior of the pe<licle-valve. ,

Hamilton group. Western Neio York.

i

Genus STROPHALOSIA, King. '

(See Plates XVu, XVI.) • |

Page 314.

Strophalosia truncata, Hall.

(See Plate XVb, fi-s. 24-2ti.)
Fig. 10. The interior of a brachial valve ; showing the cardinal process.
Fig. 11. The exterior of a brachial valve ; showing the convex umbo corresponding to the truncation of the

apex of the opposite valve. X 2.
Figs. 12, 13. Two views of a pedicle-valve ; showing the truncation of the beak. X 2.

Marcellus shales. JVestern Ne^o York.
Fig. 14. An impre.ssion of the external surface of the brachial and part of the pedicle-valve ; showing the 1

cardinal areas and minute deltidia. X 2. i

Hamilton grouji. JVear Tally, N. Y.
Fig. 15. An enlargement of the cardinal process ; showing its sinipit'. uncoalesced lobes. X 6. j

Marcellus shales. Western New York. \

Genus PRODUCTELLA, Hall.

P,nge 328.

Productella subalata, Hall.

Fig. It). Exterior of the pedicle- valve ; from one of the original specimens.
Hamilton group. Rock Island, Illinois.

I

J

-?^

113 j^i ^ 13 i£j; j: cj IP u Id ^

Palaeont.Ny.VolIV.Ptii

(■> iUM U Illll:>ll'illloll.~

Pldte A,l

>*'.
"<ii

^:S

L<^'»

'^*-i-

t.-,'ij

12

<.:*.

16

17 J

• ^ ^ ^: ??B'

as

3S

27

/ : ^^ .v^P

33

,t_"V^V

. JIL ..-,

iS?v.-.

■III'! ';.'

^v^J'

I

'W^^y

R.E Wrutneiii, del .

PLATE XVU— Continued-

Pkoductella exanthemata, Hall.

Fig. 17. The inteiior of a brachial valve ; showiiifj the ravdinal process.
Hamilton gi^oiip. Tinker's J^alls, iV. Y.

Pkoductella costatula, Hail.

Figs. 18, 19, 20. Three views of a j)eilicle-valve.

Chemung group. C/ieinung county, N. Y.
Fig. 35. The interior of a brai'.hial valve. Above the figure is an enlargement of the cardinal process.

Chemung group. Cattaraugtis cmmty, N. Y.

Pkoductella dumosa, Hall,

Fig. 21. The exterior of a pedicle-valve, showing the rounded cost;e with numerous spine-bases.
Hamilton group. Canandaigua lake, N. Y.

Pkoductella lachrymosa, C'oiu;ui, var. lima, Conrad.
Fig. 22. A view of the pedicle-valve.
Fig. 23. A pedicle-valve with somewhat more elliptical outline.

Chemung group. Cattaraugus county, N. Y.

Pkoductella Boydi, Hall.

Fig. 24. A pedicle-valve retaining the sjiines on the cardinal exti-emities.

Chemung group. Near (Philipsbiirgh) Belmont, N. Y.

Pkoductella speciosa, Hall.

Figs. 25, 26. Two views of the pedicle-valve ; showing the closely-arranged spiue-biises.
Chemung group. Chautauqua cmmty, N. Y.

Pkoductella striatula, Hall.

Fig. 27. The exterior of a pedicle-valve.

Fig. 38. Cardinal view of an internal cast of the pedicV-valve ; showing the mncular scars.

Fig. 44. An enlargement of the external surface of the sliell.

Chemung group. Chautauqua convty, N. Y.

Pkoductella hiksuta, Hall.

Fig. 28. A pedicle-valve, retaining spines near the cardinal margin.

Fig. 39. An enlargement of the cardinal process ; showing the divergence of the lobes an<l the edge of the

grooves on their posterior face.
Fig. 45. An enlargement of the external surface.

Chemung group. Meadville, Pennsylvania.

Pkoductella hystricula, Hall.

Fig 29. The interior of the brachial valve ; showing the cardinal process and the dental sockets. X 2.
Fig. 30. The exterior of the pedicle-valve ; showing the fine, closely crowded spines.
Chemung group. Chatauqua county, N. Y.

Pkoductella arcuata, Hall.

Figs. 31, 32. Two views of a pedicle-valve.

Yellow sandstones. Burlington, Iowa.

Pkoductella kakispina, Hall.

Fig. 33. A pedicle-valve with a few scattered spines.

Chemung group. Alleghany county, N. Y.

PLATE XVU— Continued.

Productella pyxidata, Hall.

Fiff. 34. The inft^rioi- of a brachial valve ; showing the cardinal process, muscular scars and brachial ridges.
Choteau limestone. Pike county, Missouri.

Productella arctirostrata, Hall.

Fig. 36. The impression of the exterior of a brachial valve ; showing that the cardinal process is quadrilo-
bate on its posterior face.

Chemung group. Cattaraugus county. N. T.

Productella hirsuta, var. rectispina, Hall.

Fig. 37. The interior of a brachial valve ; showing the cardinal process and slightly developed crural plates.
Chemung group. Steuben county, N. T.

Productella onusta, Hall.

Fig. 40. The interior of a brachial valve ; showing cardinal process, dental sockets, muscular and brachial

impressions.
Fig. 41. An exfoliated exterior of the pedicle-valve.

Chemung group. Cattaraugus county, N. T.
Figs. 42. 43. Cardinal views of internal casts of the pedicle-valve ; showing the muscular scars.

Chemung group. Conewango, N. Y.
Fig. 46. An enlargement of the surface.

Genus AULOSTEGES, von Helmersen.

Page 319.

Aulosteges Wangenheimi, de Verneuil.

Figs. 47, 48. Two views of a specimen ; showing the highly developed cardinal area and deltidium.
Fig. 49. The interior of a brachial valve. (After Davidson.)
Permian. Mii^sia.

Genus STROPHALOSIA, King,

Page 314.

Strophalosia Gerardi, Kiug.

Fig. ."iO. View of the shell ; showing the lamellose brachial valve, cardinal areas, deltidia and the umbonal
cicatrix. (After Davidson.)

Permian. (?) Spiti, India.

Genus PRODUCTELLA, Hall.

Page 328.

Productella productoides, Muichison.

Fig. 31. View from the lirachial valve ; showing the cardinal area and deltidia, and the marginal spines of
the pedicle- valve. (After Davidson.)

Upper Devonian. North Devon, England.

PLATE XVIIa.

(Figures 1-5, 8, 9, 11, 12, 14, 21, 25, 26 by E. Emmons ; 6, 7, 10, 13, 15-20, 22-24 by G. B. SiMl'SON.)
Leg-end. A. Canlinal aiv.i (iicdicle-valvp). x. Scar of attachment.

D. Deltiiiium (pedicle-valve). z. Posterior riiifre limitinjf internal cavity.

C. Deltiiiium (brachial valve). a. Anterior aildnctor scars,

j. Cardinal process. a'. Postei-ior adductor scars.

t. Teeth. r. Diductor si^i-s.

Genus STROPIIALOSIA, King.

(See Plates XVii and XVll.)
Page 314.

Strophalosia Rockfordensis, sp. IIOV.

Fig. 1. A view of an imperfect specimen which retain.'; the cardinal area and deltidiiim of each valve. X 2.
Fig. 2. Cardinal view of the same specimen ; .showing the acar of attachment. X 2.
Upper Devonian. Rockford, Icnoa.

Strophalosia crMBULA, sp. nov.

Figs 3, 4. Opposite sides of the same specimen ; showing the cardinal aieas,deUidia and scar of attachment.

Keokuk group. Lebano7i, Kentitcky.
Figs. 8, 9. Opposite sides of a larger individual, which is somewhat crushed at the apex of the brachial
valve.

Keokuk group. South of Louisville, Kentucky.

Strophalosia Keokuk, Beecher.

Fig. 5. A small individual ; showing the great length of the spines.

Fig. 6. An attached specimen ; showing deltidia, cardinal areas and adherent spines. X 2.
Fig. 7. The cardinal portion of the same specimen enlai'ged to show the prolongation of the deltidiuni into
a tube or sheath for the pedicle. X 4.

Keokuk group. Orawfordsmlle, Indiana.

Genus PRODUCTELLA, Hall.

(See Plate XVIL)
Page 338.

Productella, sp. (?)

Fig. 10. Cardinal view of an undetermined species, which retains the cardinal areas and deltidia of both
valves and the marginal spines of the pedicle-valve. X 2.
Chemung group. Q-reenviood, N. Y.

Productella pyxidata, Hall.

(See Plate XVII, lig. 34.)
Fig. 14. The cardinal portion of the pedicle-valve ; showing the area and teeth. X 2.
Choteau limestone. Pike county, yiissouri.

Genus PRODUCTUS, Sowerby.

(See Plates XVI U and XIX.)
P.-ige 321.

Productus (Maeginifera ? ?) DissiMiLis. Hull (= Piodmlella Hallana, Wulcott).

Fig. 11. The interior of a pedicle- valve; showing the sharp, papillose ridges or platforms diverging from

the umbo. X 2.
Fig. 12. The interior of a brachial valve which shows corresponding pitted I'idges diverging fi-om the bases

of the cardinal process. This specimen also shows the remarkably extended brachial areas.

X 2.

Upper Devonian. Lime Creek, Iowa.

PI>ATE X^^IA— Continued.

Productus (Mahginifera) Lasallensis, Worthen.

Ki^. 13. The iiilurioi- of a bracliial valve ; showiiijf the chaiaiiler of tlie iiilenial ridge (z), dietinguiahiiig the
subgenu.s Mahginifera. In this species pr(>l)ably occurs the most extreme develoiiment of this
feature among- tlie American proiliictids. X 2.

Uppei- Carboniferous. La Salle, Illhm'ifi.

Productus magnus, Meek ami Worthen.

Mg. 15. A much flattened pedicle-valve ; showing the original lengtli of the spines about tlie margins.
Keokuk group. Crawfordsville, Indiana.

Productus semireticulatus, Martin.

Kig. IH. A portion of the interior of a brachial valve enlarged to show the structure of the brachial ridges,
X 3.

Upper Carboniferous. Perry comity, Ohio.

Fig. 17. Cardinal view of an internal cast of the pedicle-valve; showing the impressions of the cardinal

area, the posterior and anterior adductor and the diductor muscles.
Fig. 18. The interior of a brachial valve, drawn from a gutta-percha impression of an internal cast ; showing

the muscular scars and the peculiar structure of the brachial areas.
Coal Measures. Newcastle, Ohio.

Productus symmetricus, McChe.sney.

Fig. 19. Postei'ior view of the cardinal process ; showing its great elevation and strongly tripartite division,
the middle lobe being produi'ed by the coalescence of the inner members of the two principal
divisions of the process. X 3.

Fig. 20. A portion of the brachial valve enlarged to show the structure of the brachial ridges or areas.
The surface within the curved ridges is covered with irregulai' clusters of fine granules, which
become more widely scattered in the centi'al region about the median septum. The origin of
this structure, as well as that seen in figures 16 and 18, has not been ascertaineil. X 2.
Upper Coal Measures. Near Katisas City, Missouri.

Productus punctatus, Martin.

(See Plate XIX, tigs. 14-lB.)
Fig. 21. The interior of a brachial valve of a vei-y large and finely preserved specimen. The cardin.al pro-
cess shows the coalescence of the inner ajiophyses, the deep median groove on its surface indi-
cating the original division into two lobes. The mascular impre.ssions are thickened, strongly
arborescent, and show a faint division into anterior and posterior scars. Though so well pre-
served, the specimen bears no ti-ace of the brachial ridges.

Upper Coal Measures. Near Kaii-ia/t City, Missouri.

Productus .^quicostatus, Shunuird.

Figs. 22, 23. Two views of a specimen from which the upper or visceral portion of the pedicle-valve la
bi'oken, exposing the flattened surface of the lower valve. These figures are inti-oduced to show
the jjcculiar mode of growth of the shell on the anterior margin, a tendency frequently exhib-
ited by the Striati, and which, in its exti-enie development, results in an enfolded exi)ansion oi-
complete tube, as in P. probo.scideus (Proboscidella).
Coal Measures. Nel/i-aska.

Productus ( ? auriculatus, Swallow.)

Fig. 24. The extei-ior of a (ledicle-valve, the surface of which is tVee of spines except along the cardinal
margin.

Coal Measures. Near Kaiuias City, Missouri.

Genus STROPHALOSIA, King.
Strophalosia SPONDYLIFORmis, While and St. John.

Figs. 2,">, 2(3. Opposite sides of a sjiecimen ; showing the cardinal areas, deltidia and scar of attachmeut.
Coal Measures. Missouri.

PaIaeont,N,r.Vol,rV"Pt,n = Vol.Vin

Product) dae .

('iMiciic Tlluslialions

Plate XVE A

E.Emmons del

Pha.AsLluh.

PLATE XVin.

(Figures 1-5, 11-17, 19 by K. P. Whitfield; 6-13, 18 by F. B. Mebk.)
Legend, j. Caidiiml process. a. Anterior ailductoi's.

s. Septum. a'. Posterior adductors.

V. Brachial ridges. ^ r. Diductors.

Genus PRODUCTUS. Sowekby.

(See Plates XVIIa, and XIX.)
Page 3-21.

Productus Newberryi, Hall.

Fig. 1. The exterior of a pedicle-valve; showing the numei-ous spine-bases and lu^tainiiif,-- the sjiines at the
cardinal extremities.

Waverly sandstone. MeUiiia, Ohio.
Fig. 2. An internal cast of the united valves ; showing the mu.sculai- impressions of th(! brachial valve and

the bi'achial ridges.
Fig. 3. An internal cast of a pedicle-valve ; showing the adductor and diductor impressions.

Waverly sandstone. Newark, Ohio.

Produotus, sp. ? compare Prattenanus, Norwood.

Fig. 4. An undetermineil pedicle-valve belonging to the group of the Striati.
Waverly sandstone. Newark, Ohio.

Productus, ? sp. ?

Fig. 5. Profile of a pedicle-valve, with spiniferous custae.

Chemung group. Cattaraugus county, N. Y.

Productus Flemingi. Soweiljy, var. Burli.vgtonensis, Hall.

Figs. 6, 7, 8. Three views of a pedicle-valve.

Burlington limestone. Burlington, Iowa.

Productus mesialis, Hall.

Figs. 9, It). Two views of a pedicle-valve.

Keokuk gi'oup. Naiivoo, Illinois.

Productus srmireticulatus, Marl in.

Fig. 11. A cast of the exterior of a laige brachial valve ; showing the surface charactei's.
Fig. 12. A cardinal view of the pedicle-valve.

Fig. 13. A view of a specimen having the valves united and retaining some of the cai-diiial spines on the
pedicle-valve.

Keokuk group. Warsaw, Illinois.

Productus alternatus, Norwood and Prattcn.

with the peculiai' sur:
Keokuk grouj). Illhuiis.

Fig. 14. A pedicle-valve with the peculiai- surface markings, which are due to the exfoliation of the siiiue-
bases.

PLATE XVIII— Couliiiucd.

Peoductus vittatus, Hall.

Fig. 15. A pedicle-valve with a somewhat exfoliated surface, but retaining- the concentric growth-lines.
Fig. 16. The interior of the brachial valve ; showing the muscular impressions and the cardinal process,

bifid (in its upjier surface.
Fig. 17. The posterior fare of the cardinal process of the valve represented in fig. 16 ; showing a thi-ee-fold

lobation. X 3

Keokuk group. Near Keokuk, Iowa.

Productus tenuicostatus, Hall.

Fig. 18. A profile view ; showing the fine surface striation and the expanded anterior margins.
St. Louis limestone. Milan, Illinois.

Productus ovatus, Hall.

Fig. 19. A profile ; showing the extremely produced anterior margin.
Keokuk limestone. New Providence, Indiana.

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PLATE XIX.

(Figures 1-23 by R. P. Whitfield.)

Legftnd. j. C:miinal [irocess. a'. Posterior adductors,

a {=;,'■"). Anterior adductors. v. Bracliial ridges.

Genus PRODUCTUS, Soweuby.

(See Plates XVIIa and XVIII.)
Page 3-21.

Productus (Marginifera) splendens, Norwood :uk1 Prattcu (P. lonffispinus, Sowerhy).

Fiffs. I, 2, 3. Three views of a specimen with a few ribs and scattered spine-bases, and a nacreous shell
texture.

Upper Coal Pleasures. Winttrstt, Iowa.
V'\g. 4. The interior of a brachial valve; -showing the cardinal proces.s, mu.scular impressions and brachial
ridges. At xx is a row of short spinules which project from the inner surface of the shell, a
feature more highly develoiied here than in any other species observed. The submai-ginal
ridges which ch.aracterize Waagen's subgenus M.arginifera are not highly developed in this
specimen. X 2.

Coal Measui'es. La 8alle, I llinois.

PRODurTus Nebrascensis, Owen {= J\ anpevsH.t. McChe.siiey).

Figs. 5, 6, 7. Three views of a specimen ; showing the great abundance of short spines.
Coal Measures. La Salle, Illinois.

Productus costatus, Soweiln-.

Fig. 8. The exterior of a pedicle-valve ; showing the general character of the specimens referred to this

species in this country.
Figs. 9, 10. Profiles of two individuals of different size.

Fig. 11. The interior of a brachial valve, with the muscular impressions and brachial ridges.
Fig. 12. An enlargement of the jiosterior face of tlie cardinal process ; showing its thickened base and trilo-
bate character. X 3.
Fig. 13. An internal cast of the xieJicle-valve; showing the diductor and ailductoi' muscular scars.
Coal Measures. Wlriterset, Iowa.

Productus punctatus, Martin.

Fig. 14. The interior of a brachial valve.

Fig. 15. The cardinal process of the same specimen, viewed tVom the postei-ior side. X 3.

Fig. 16. The same in profile. X 3.

Coal 'Measures. Missoui-i.
Figs. 17, 18. Two views of a pedicle- valve ; showing the sjnniferous bands which form concentric annulations.
Referi-ed to this species with doubt.

Coal Measures. Locality?

Productus semireticulatus, Martin.

Fig. 19. The central portion of a brachial valve, which retains with unusual distinctness the mu.scular and

brachial iinpi'essions.
Fig. 20. Posterior view of the cardinal process ; showing the complete coalescence of the inner divisions of

the two lateral lobes. X 3.
Fig. 21. The inner face of the same. X 3.
Fig. 22. The interior of a small brachial valve.

Fig. 23. The interior of a pedicle-valve ; showing the adductor and diiinctor scai-s.
Coal Measures. Itaituba, Brazil.

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PLATE XX.

ORTIIIS, Dalman.

IPage 217.

Orthis flabellites, Hall.

(See Plate V. figs. 37-41.)

Fig. 1. An interual cast of the jiedicle-valve ; showing- very distinctly the rhai-arter of the musi-ulai- scar,
and the simple plication of the surface.

Niagara group. Hamiltmi, OntarioA

Ortmis punctostriata, H;i1!.

Page 217.
Figs. 2, 3. Two views of a slightly distorted indiviilual, retaining both valves.

Fig. 4. An enlargement of the surface j showing the rows of superficial punctje between the strise.
Niagara group. Lochport, N. T.

Orthis (Rhipidomella) Burlingtonensis, Hall.

(See Plate VIa, fig. 13.)
Fig. 5. An exfoliated pedicle-valve ; showing very distinct impressions of the adductor and didnctor scar.
Fig. 6. Posterior view of the cardinal process and crural plates of the brachial valve. X 4.
Chert of the Bui-lington limestone. Pike county, Missouri.

Orthis (Rhipidomella) Michelini, Leveill6.

Fig. 7. The interior of the pedicle-valve ; after Davidson. (Bi-itish Carboniferous Brachiopoda, pi. xxx,
fig. 11.)

Carboniferous limestone. Ayrshire.

ORTHOTHETES, Fischer de Waldheim.

Page 253.

Orthothetes deformis, Hall, var. sinuata, var. iiov.
(See Plate IX, fig. 32.)

Figs. 8, 9. Two views of a specimen ; showing the distortion of the beak and the median sinus on the bra-
valve, which is a characteristic featui-e of some species of Derbva. Further examination will
probably prove this form to be a distinct species.

Lower Helderberg group. Cumberland, Md.

DERBYA. VV^aagen.

Page 261.

Derbya Correana, Derby.

(See Plate XI. figs. 18-22.)

Figs. 10, 11. Two views of the umbonal portion of an internal cast of a pedicle-valve, broken to show the filling
of the umbonal cavity between the united dental plates. Fig. 10 also shows the impression of
the median septum supporting these plates. X 2.
Carboniferous limestone. Itaituha. Brazil.

Derbya crassa, Meek and Haydeii.

(See Plates X, XIb, XIc.)

Figs. 12, 13. The interior of both valves of the same specimen ; showing the muscular scars, median septum
and cardinal process.

Upper Coal Measures. Near Kansas City, Missouri.

PLATE XX— Continaeil.

ANOPLIA; SUB-GEN. NOV.

Page 309.

Anoplia nucleata, Hall.

(See Plate XVITa, 6gs, 17. 18.)
Vig. 14. Internal cast of a iiedicle-valve ; showing the impi-e.ssion of the short median septum, and the pus-

tulose character of the pallial region. X 'i.
Fio- 15 The interior of a brachial valve ; showing the muscnlar impression and the pustulose surface.

"' ' The cardinal process is bilobed, hot is probably shorter than is noraial for the species. X 3.
Fig. 16. The exterior of the brachial valve; showing the smooth surface. X 3.

Oi-iskany sandstone. Jones comity, Tllinois.
Fig 17. The central cardinal portion of an internal cast of the pedicle-valve ; showing the filling of the ob-
lique cardinal tubes which do not peneti-ate to the external surface. X 6.
Oriskany sandstone. Columbia county, N. Y.

CHRISTIANIA, gen. nov.

Page 298.

Chkistiania subquadeata, Hall.

(See Plates XV and XVIIa.)
Figs. 18, 19. Two views of the pedicle-valve ; showing its elongate form, incurvature and smooth or squam-
ous exterior. X 2.
Fig. 20. The exterior of the brachial valve, which shows the cardinal process and edges of the crural
plates. X 2.

Lower Helderberg group. Perry county, Tennessee.

LEPTiENA, Dalman.

Page 276.

Lept^na rhomboidalis, Wilckeus.

(See Plates VIII and XVIIa.)
Fig. 21. The deltidial area of both valves of a small individual. X 3.
Fig. 21a. Longitudinal section of the two valves; showing the degree of curvature.

Fig. 22. The intei-ior of a brachial valve ; showing very distinctly the division into anteiior and posterior
musc\ilar scars.

Hudson River gi-oup. Cincinnati, Ohio.
Fig. 23. The interior of a brachial valve, in which the margins of the broad posterior adductors have be-
come elevated into free alate extensions. X 2.
Niagara group. Waldron, Indiana.
Fig. 24. The muscular area of the brachial valve, tigureil on Plate VIII (tig. 31) ; enlarged from a gutta-
percha impression. The area is subdivide<l into three pairs of scars, the elongate central pair
being probably accessoi-y to the posterioi' adductors. X 3.
Waverly group. Medina county, Ohio.

Lept.^na ? UNicosTATA, Meek aiul Worthen.
See Plate XVIIa, fig. 39.
Figs. 25, 25a. The interior of a brachial valve and cardinal area of a pedicle-valve ; showing characters of
LBPT.EBA.

Hudson Rivei- group. Ohio.

STROPHOMENA, Rafinesque (de Blainville).

Page 245.

Strophomena Winchelli, .sp. nov.

(See Plaie IX, fig. 12.)
Fig. 26. An enlargement of the muscular area of the brachial valve cited ; showing the broad posterior and
elongate anterior scars. X 3.

Trenton limestone. Janesville, Wisconsin.

m Si ^ '£ lii 2 © IF £} m j^

!3Parl N rVol.IVF- U = Vo: V"'

'■(•iiorii lllw^frilioiK

Plate XX

E.Emmons del

Fr.i!.Ast-iiih.

PLATE XX— Continued.

RAFINESQUINA, gen. nov.

Page 2S1.

Eafinesquina alternata, Corn-ad.

(See Plate VIII.)

Fig. 27. The interior of a brachial valve, with sharply defined anterior and posterior adductor seai-s, and

showing faint traces of recurving vascular sinuses.
Fig. 28. The interior of a pedicle-valve, in which the muscular scars have their normal character.
Hudson River group. Cincinnati, Ohio.

STROPHEODONTA, Hall.

Page 284.

STEOPnEODONTA PROFUNDA, Hall.

(See Plate XIII, figs. 1-5.)

Fig. 29. An internal east of the pedicle- valve ; showing the broad flabellate diductor .scar.s, meeting in front

and enclosing a i-ather broad pair of adductoi's.
Fig. 30. An enlargement of the muscular area of the brachial valve. X 1^.
Fig. 31. The surface strife. X 2.

Niagara limestone. Near Milwaukee, WiscoTisin.

STROPHOMENA, Eafinesque (de Blainville).

Page 445.

Strophomena Conradi, sp. nov.

(See Plate XI A, fig. 3.)
Fig. 32. The profile of a specimen showing only the upper or brachial valve.
Fig 32a. Outline profile of the same specimen.

Trenton limestone. Treiiton Falls, N. Y.
Fig. 33. Outline profile of figm-e cited.

QH Natural history of New York

105

N7NS

V.29

Biologica!

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