Memoirs MCZ 2503

—

/Demolrs ot tbe /IDuseum of Comparative Zoology

AT HARVARD COLLEGE.
Vol.

XXV.

No.

3.

SOME NEW AMERICAN FOSSIL
CRINOIDS.

BY

FRANK SPRINGER.

WITH

SIX PLATES.

CAMBRIDGE,
IPrtnte5

for

U.

S. A.:

tbe nDuseum.

July, 1911.

'
-i)



SOME NEW AMERICAN FOSSIL CRINOIDS.

During somewhat
have come into

my

to species hitherto

protracted researches upon the

possession a considerable

un described, and

of species imperfectly

much

also

in

some specimens

purpose, already too long delayed, tempts

new

me

there

of specimens belonging

figures.

due course of systematic work.

of a remarkable

Crinoids,

excellent material illustrative

known, or described without

remain to be dealt with
describing

number

fossil

Most

The

obligation of

species entrusted to

to publish along with

of these

it

me

for that

some others

which are specially notable, either by way of extending the stratigraphic or
geographic range of certain groups, illustrating species hitherto unfigured, or

throwing
appeal to

which

I

upon unsettled questions of classification. These objects, which
me with more interest than the mere description of new species, and

light

am

sure are of greater service to science, have induced the present

contribution.

CAMERATA.
DIMEROCRINIDAE.
DiMEROCRiNUS

apud Miu-chison.

Phillips

1881.

Silurian System, p. 674, PI. XVII, figs. 4, 5.
Dimerocrinus Wachsmuth and Springer, Revision of the Palaeocrinoidea,

1897.

Thysanocrinus Id. N. Amer. Crin. Cam., 190.

1836.

II,

197;

III, 101.

This hitherto exclusively Silurian genus was proposed by PhiHips without
definition,

but upon two species, D. decadactylus and D.

he gave a brief description and figures

bj'

as familiar forms at Dudley, England;
principal

museums, under

Phillips's

icosidactylus, of

which they can be

which

easily recognized'

specimens of them are found in the

names.

From

these species the generic

characters are readily determinable, but were not correctly understood until


FOSSIL CRINOIDS.

118

Wachsmuth and

pointed out by

basals, not observed

by PhiUips or other authors

Phillips's

genus (Rev.

Pal., II, 198);

discovered the infra-

made them

This

before.

we then ranked

congeneric with Hall's later Thysanocrinus, which

under

who

Springer in 1881,

as a

synonym

an arrangement which we afterwards,

without good reason, reversed (N. A. Crin. Cam., 190), taking Hall's name,
Thysanocrinus, for the genus and family.

cised,

and must be abandoned.

This procedure has been justly

Therefore

I

use the

names

head

at the

criti-

of this

and Thysanocrinus, as adopted in the North
American Crinoidea Camerata, and for the same generic type, viz a Camerate,
section instead of Thysanocrinidae

:

dicyclic Crinoid, with radials in contact except at the anal side;

of interbrachial plates;

crinus

and Glyptaster

biserial

clearly

and anus without a tube.

arms;

go

as

several ranges

synonyms.

Angelin's Eucrinus, which

included several species substantially like D. decadaciylus, was at
to be upheld

by

Thysano-

first

sought

restricting Dimerocrinus to species with only ten simple arms;

but the addition of another order of brachials, giving twenty arms simple

like

the others, seemed such a very slight modification of the same plan of structure,

that this distinction was afterwards abandoned, and

all

the species thrown

together under Dimerocrinus except the two figured by Angelin as E. venustus

and E. minor

(Icon. Crin.

PI.

Suec,

XV,

5,

figs.

7,

16).

In these there

is

a

wholly different arm structure, with frequent branching at long intervals, and
the arms from the IIBr up, below the axillaries as well as above, biserial, as in

These, however, appeared from the figures

Megistocrinus, Abacocrinus, etc.
to

have the radials separated

we proposed

What

is

all

around as

them

in the Rhodocrinidae,

and

for

we have the

first

evidence

the genus Anthemocrinus.
of especial interest

now, however,

of persistence of this family type into the

is

that

Middle Devonian.

But

for the

non-

and somewhat obscure Lower Devonian form described by Jaekel
as Orthocrinus, the known species of this family have been restricted to the

characteristic

Silurian

and

earlier.

Schultze's

"

Rhodocrinus" quinquelobus, which he classed

with Thysanocrinus, and which we placed under Eucrinus (Rev.
is

— a Batocrinoid, as
monocyclic

from the Hamilton beds near

will

be shown

Louisville,

later.

A

Pal., II, 197),

very distinct specimen

with a calyx which cannot be excluded

from the family diagnosis, compels us to extend

its

range accordingly.


FOSSIL CRINOIDS.

DiMEROCRINUS SPINIFERUS,
Plate III,

Calyx elongate with straight

trum

figis.

sides,

119

sp. IIOV.

lla-d.

truncate above and below like the frus-

an inverted pyramid; rather wider than high, widest just above the
arm bases, enlarging from base to arm facets as 1 to 1.8; IBB and lower part of

BB

of

included in lower plane.

mm.; width

IBB

of

at base, 10

good

Dimensions

arm

at

mm.,

of the only specimen:

horizontal, projecting well

size,

mm.

bases, 18.5

height 17.5

Base broad and

flat;

beyond the column, with tips

IBB — the largest
—
the lower central part produced into spiny nodes, about
plates in the calyx
bending up;

on a

level

BB

three times as wide and twice as high as

with the infrabasals; smaller spines form a low ridge leading from

RR

these to the middle of the radials.

a

little

thirds as high,

surmounted by a small spine

normally three

in

one ray) one fourth the

;

wider than BB, but only two

followed by two narrow IBr (ab-

size of the radials, also spiniferous;

and these by one very large, overhanging, spiniferous IIBr at each side, bearing
the arm facets; between these a large, wedge-shaped, tumid plate, and above
this a pair of further projecting spinous plates

the widest part of the calyx.

overhang the arm facets and mark

First iBr large, followed

by two

plates,

and then

two ranges more connecting with others in the tegmen, each bearing a
central spine;

leading to a subcentral opening in the tegmen.

arms unknown.

facets very small;
all

plates bear one or

and the tegmenal
and well defined.
Type.

short,

anal area similar, with three plates in the second range,

more small

Arm

and

openings two to the ray;

Tegmen moderately

lobed, perfectly flat;

spines, the largest being

on the posterior

oral

margin above the arm bases; oral plates large
Column facet large and round.

axillaries at the

In the author's collection.

Horizon and Locality.

Hamilton Group

of the

Middle Devonian.

Charles-

ton, Clark county, Indiana.

The

description

but the unique type

much

is
is

rather

more

series give to the calyx a strikingly angular

appearance, unlike that of any other of the genus.

may

desirable,

distinct,

rows passing from basals up the radial

size of the facets I suspect there

is

and others would probably not show
the characters stated.

The spiny ridges and

remarkably

substantial variation in

of the individual specimen than

From

the extremely small

was something peculiar about the arms; but we

not expect to see them, as they are almost never found preserved in the


FOSSIL CRINOIDS.

120

they come out from under the overhanging

Crinoids of that prolific locality;

tegmen plates much

and were no doubt as

like those of Gilbertsocrinus,

small,

and not improbably pendent.

BATOCRINIDAE.
DoRYCRiNUS Roemer.
This case

is

the reverse of the

Instead of bringing a Silurian genus

last.

forward to the Devonian, we have a species which carries a Carboniferous genus

back
in

The Batocrinidae

to that age.

{sensu

but Dorycrinus and

the Ordovician;

its

Wachsniuth and Springer) began
immediate congeners have been
"

Lower Carboniferous, except for Actinocrinus " cassedayi Lyon, and some unfigu red species by Hall from the New York Hamilton,
and the small "Actinocrinus" prumiensis of Miiller, to which must be added for
hitherto restricted to the

i-easons already stated, the

"

spiniferous Dorycrinus, until now, has been supposed

Burlington Limestone; but here
locality as the last:

The

Rhodocrinus" quinquelobus of Schultze.

—

is

to begin in the

Lower

a good one from the Hamilton, at the same

Dorycrinus devonicus,
Plate III,

figs.

sp.

12o-d,

nov.

13.

Caljrx elongate, narrowly turbinate to the first axillary, greatly enlarged

deeply lobed above;

spreading as from

sides to 3 at the axillary IBr,

real

1

and

at the base gradually with straight

and then suddenly

to 5 at the

arm

bases

;

narrowly

truncate below, and highly arched in the tegmen with deep interbrachial con-

tegmen much larger than dorsal cup, and bearing large projecting
Dimensions of medium sized specispines on the interambulacral axillaries.
men: height to bottom of arm bases, 12 mm.; total height, 23 mm.; width at
strictions;

base, 4

mm.;

at axillary IBr, 12;

Basals forming an erect cup.

and

at

arm bases

— the widest part — 21 mm.

Radial series elongate, with low median ridge,

diminishing in width and branching twice in the calyx, giving 4
to the ray, facing

elongate;

outward

arm openings

arm openings
lower edge of arm

in large projecting lobes;

radial lobes very large, being,

from the

nearly as high as the whole of the dorsal cup below them;

tuberance stands above each pair of

arm

bases,

large

and

facets up,

a large hollow pro-

and another

still

larger one


FOSSIL CRINOIDS.
above and between them

in the

tegmenal

121

Arms unknown.

axil.

spaces wide, occupied by about 5 ranges of plates, in order
dorsal cup,

and several more above the

level of

Anal area

to a connection with the orals.

arm

bases,

Interbrachial

between the lobes

similar, with 3 plates in the

range, leading to a subcentral opening in the tegmen, directed up.
high, low convex on top, broadly curving

down

interradially

in the

1, 2, 3, etc.,

second

Tegmen

between the

lobes,

which are very high, surmounted by the protuberances already mentioned;
•these are hollow, composed of small plates, and formed the sockets for large
spines,

none of which are preserved; tegmen plates very small and numerous;

Column

orals not differentiated.

Types.
in

Figs. V2a-d are in

facet round, filling entire width of base.

Walker Museum, University

of Chicago.

Fig. 13,

author's collection.

Hamilton Group, Middle Devonian.

Horizon and Locality.

Charleston,

Clark county, Indiana.
Besides the two very good specimens figured,

I

have three others not so

complete, but showing the characters of the species with remarkable constancy;
the low radial ridge

that

I

know

is

equally distinct in

The

all.

nearest related form to this

the species from an about e([uivalent horizon in the Eifel, de-

is

scribed

as Rhodocrinus quinquelobus

PI.

similar narrow, turbinate, elongate calyx, with prominent

by Schultze
VH), which has a

lobes in the radial regions;

but no spines.

he with

it

from that group, considering

is

(loc. cit., 57, text-fig. 10),

The

difficulty

more than

I

wholly incorrect and misleading;

can understand.

with radials separated
a single "ziemlich

all

(loc. cit., PI. VII, 6).

The diagram

it

20 arms.

we withdrew

"

how

from

it

was based upon

and "verdriickte" specimen,
exposed, and of which only that view

unvollstandigen

Schultze,

his specimen,

represents a dicyclic Crinoid

around by a large interradial plate;

the posterior side was chiefly

its

grows out of the above

careful observer as he usually was, could have constructed
is

its affinities

a Rhodocrinoid (N. A. Crin. Cam., 192);

it

neither of these assignments can stand.

mentioned diagram, which

57,

Wachsmuth

under Eucrinus on account of

Afterwards, following Schultze's diagram
it

Schultze declared

Thysanocrinus, as a subgroup within Rhodocrinus.

and Springer accordingly placed

Eifelk.,

This species has been the subject

of uncertain treatment in systematic literature.

to

(Mon. Echin.

in
is

which
figured

This figure shows three large basal plates, each followed

somewhat nodose, radials, and these in succession by two
primibrachs, the second one axillary and leading to two arm openings; that is,
four ranges of plates up to and including the axillary brachials (radials of third
alternately

by

large,


FOSSIL CRINOIDS.

122
order as then called)
like that there is

;

there

is

no sign of infrabasals, and in a slender dorsal cup

no possible room for interradials between the

Yet

radials.

in

the diagram there are five infrabasals, large basals, and three orders of radials
including the axillary.

description combines the facts of the figure with

The

the errors of the diagram in a singular way, indicating a strange confusion of
ideas.

Slightly condensed

it

reads as follows:

The "Basaha" (number not

form a low funnel, to which circumstance the calyx owes its elongate
form (showing that he means the first row of erect plates seen in the figure,

stated)

and not any

invisible plates below, or above,

them)

;

the lower part of the six-

sided "Parabasalia" project "knopformig" (answering precisely the description
of the (first) radials in the figure)

;

upon

these,

which consists

angles, follow five rays, each of

is

of "drei Radialia," the

upper of

beyond a doubt that the lowest

these axillary (whereas the figure shows
three radials whose upper plate

into their reentering

wedged

the axillary,

is

the

"

of the

"

knopfformig

plate,

resting upon the reentering angles of the "Basalia" which form the "Trichter,"

and that there
rest

is

no room

for

any "Parabasalia" at

upon the horizontally truncate edge

Interradial of the
in the second

first

all)

;

the Interradials, which

of the "Parabasalia," shov.^ a larger

order, etc. (the only possible horizontally truncate plates

range are the radials and the anal plate, which the author must

have been thinking of when he wrote this).
I have good specimens of an undescribed elongate form substantially the same
as Schultze's species, from the

Devonian

of Colle, Spain,

— a perfectly

plain

Batocrinoid.

INADUNATA.
GASTEROCOMIDAE.

Hitherto no representative of the assemblage of peculiar dicyclic Eifelian
the
genera grouped under this family has been reported in this country, except
It is now known,
species described by Hall under Myrtillocrinus americanus.

however, that there are at least two other genera in our approximately equivalent

Middle Devonian that must be referred

to

it.

The genus Arachnocrinus was founded by Meek and Worthen (Geol. Surv.
Hall as Cyathocrinus
Illinois, II, 177) upon a species which had been described by
bulbosus (15th Rept. N. Y. St. Cab., 1860, 123) from the

Helderberg =

Corniferous) of western

New

York;

this

Onondaga (= Upper

was done chiefly upon


FOSSIL CRINOIDS.
the character of

its

the structure of

its

ponderous arms, and without any accurate knowledge of
It was said to have small infrabasals (afterwards
calyx.

by Wachsmuth and Springer, Rev.

stated

plate resting

123

Pal., I, 94, as five),

upon the truncated posterior basal; and

I,

single anal

for these reasons

Wachsmuth and

always been ranked among the Cyathocrinidae.
(Rev. Pal.,

and a

has

it

Springer

two additional species from the equivalent rocks
Kentucky, in one of which they observed a lateral opening

94) described

near Louisville,

above the posterior basal, and between two adjoining radials; but this
attracted no special attention.
Nothing was then known of any unusual

directly
fact

features of the

column or

axial opening.

Investigation of the original specimens upon which these several species were
described, and of a considerable quantity of additional material since obtained

from the typical

New York and

localities in

near Louisville, has disclosed with

perfect clearness the characters of the calyx;

leading to the interesting result

that the remarkable arms of the American species belong to a calyx in no
distinguishable from certain Eifel species described under the

Some

of the

New York

material above mentioned

is

name

American

in the

way

Gasterocoma.

Museum

Natural History, including one of the types of C. hulbosus, and some in the

of

Museum

State

For the opportunity to use

at Albany.

in this

it

indebted to the courtesy of Prof. R. P. Whitfield, since deceased, and Dr.

The remainder

Clark, State Palaeontologist.

is

in

my own

The genus Gasterocoma was proposed by Goldfuss (and

I

am

J.

M.

work

collection.

its

synonyms, Cera-

mocrinus and Epadocrinus, by Johannes Miiller), and afterwards fully described,
illustrated

and discussed by Schultze (Mon. Echin.

Eifelk.,

definite information as to the character of its arms.

95

et seq.),

without

It belongs to the

peculiar Crinoid fauna characteristic of the Middle Devonian of the Eifel
tains

and adjacent

my

and Schultze; and

knowledge, been recognized elsewhere.

genus, and of the

little

The

it

has not hitherto,

leading characters of this

group of peculiar Crinoids associated with

the anus passing out through the dorsal cup below the level of the
(2)

it,

are, (1)

arm

bases;

horseshoe-shaped radial facets, with a dorsal canal extending throughout

radials

pierced

and arms

by a

;

and

(3) in

central axial,

Comparing the calyx
it

Moun-

which has been so ably studied, and thoroughly

region,

described, in the works of Roemer, Miiller,
to

very

now appears

that

the level of the

it

arm

most

of

and four

of the

them an undivided

infrabasal disk, usually

peripheral, canals.

above mentioned American specimens with

this,

has an anal opening lateral through the dorsal cup, below
bases,

between the posterior basal and the two posterior

FOSSIL CRINOIDS.

124
rounded radial

radials; large,

facets, directed

outwards; a dorsal canal, or dorsal

extension of the axial canal, perforating the radials and arms, entirely separate

from the ventral or ambulacral groove; undivided infrabasals; and a quadripartite axial opening, consisting of a central canal surrounded by four smaller
peripheral ones, extending from the column into the base of the calyx.

the only point remaining as to

these characters belong equally to Gasterocoma;

which a difference might be noted
plate

may

lying, as
exist.

it

At

not be in any

the plate above the anal opening.

way homologous

does, anterior to the opening,

events

all

and absent

species,

is

it

wholly

is

to the anal plate

and

Rept. N. Y.

is

New York

in

species;

both

specimens where the structures

all

the specimen in which he supposed

St. Cab., PI. I, fig.

19)

corroded, so that the sutures cannot

is

all

in

be definitely traced;

was (15th

which we have several much better preserved,

it

has an irregular

and there are possibly only

In none of the other

3 herein).

fig.

it

poor preservation, the surface much

aspect, the space for the infrabasals looks four-sided,

of

may

one Kentucky

Hall's description of an anal plate touching the basal

incorrect;

four basals (PI. II,

of other genera,

inconstant, being present in

the latter the radials meet above the opening in

in C. bulbosus

.t

This

whatever anal tube

in front of

in the other, as well as in the

can be distinctly seen.

All of

New York

specimens,

there any such plate as he

is

describes.

Now

as to the so-called anal plate, there

which he

calls the "interradial," in as

one species, G. antiqua (Mon. Echin.
1.

The

many

2.

A

3.

Two

Eifelk., 97, PI. XII), viz:

plates, of the

marked

Id,

figures of G. a/iirgwa
1/ should be

4.

Three

5.

No

form and

size of

No.

is

1,

it

:

Fig. lb.

bisected vertically:

l/i

Fig. la
thirtl

should be ^;

1

i

should be

/i

;

k).

plate at

two smaller ones under the usual
all,

large one:

the posterior basal reaching the tegmen,

opening being under the right posterior radial: Fig.

radials

and

confusion in the designation of several of the other

on this Plate: 1^ should be/;

plates,

plate,

in

—

being the isolated figure between the second and

rows from the top; there

No

them

1.

triangular plate, with the radials closing above

(erroneously

6.

.specimens, six of

typical form, with a quadrangular plate between the radials

above the opening: Fig.

and

among

Schultze enumerates and figures seven different conditions

the Eifel specimens.
of this,

the greatest irregularity

is

Fig. Id.

and the anal

le.

the opening directly through the posterior basal, and the

meeting above

it:

Fig. Ic.


FOSSIL CRINOIDS.

A

7.

125

and

plate below the opening, between the radials

terior basal:

resting on the pos-

Fig. 2.

With such an admitted
the differences observed

among specimens

diversity

in the typical locality,

the American species, even granting Hall's

among

doubtful anal plate (which would be the same as case 7 above), there can be no
generic distinction based

upon

in favor of referring

these species to the

all

remembered that the arms

section;

this agrees

(loc.

known beyond

it

will

be

the lowest

I

have

and which are simple, composed of brachials
wholly different from those of Aracknocrinus.

this genus,

about as wide as long,

That there may be important

arm

differences in

group having substantially the same calyx,

New York Onondaga

discovery in the

But

with a set of detached arms from the Eifel which

supposed to belong to

this

impression would be

are high, with a round cross-

p. 95)

cii.,

first

European genus.

of Gasterocoma are not

which Schultze says

brachials,

and the

this character;

is

of another

structure

among forms

further indicated

form of

of

by the

this peculiar type,

having a similar calyx and axial canal but a totally different arm structure, for

which

have proposed the name Schultzicrinus

I

of the very heavy,
brachials,

it

has

many

The

branching arms of Arachnocrinus, with short, deep

radial facets are directed

entire distal face of the radial,

and Gasterocoma.

Instead

1-7).

simple arms, which are broad and shallow like those of

five

Synbathocrinus.

(PI. Ill, figs.

The

which

is

upward, and

fill

almost the

not usually the case in Amchnocrinus

position of the radial facets in the latter

two genera

very similar, that of Gasterocoma seeming to represent a smaller arm.
for this small difference,

which

should not be able, from the

distinct

is

American forms ought

until further discoveries,

it

Except

not very well marked in the specimens,

caljTc alone, to

to

we

say which of these two thoroughly

be referred to Gasterocoma.

seems best to

is

let

Therefore,

the two genera stand, and add a

third.

Another form
Myrtillocrinus,

of

somewhat

which

similar habitus

also has the radials perforated

lacks the laterally opening anus,
located, as

and

in fact

none of the specimens show

another specimen of the American species,

with the other genera

XVI,

figs. 2,

it

I

is

base,

is

by a dorsal canal; but
unknown how the anus

it

is

have refigured the type and

M. americanus
It has

of Hall, for

comparison

a very deep radial facet,

unknown, must have been round and heavy.

specimen was figured by Miss E.

1904, PI.

it.

(PI. Ill, figs. 8a, b, 9).

indicating that the arms, hitherto

A

and with an undivided

Wood

(Smithson. Misc. Coll.,

2a) consisting of the calyx with

some

of the

XLVII,

arms and


FOSSIL CRINOIDS.

126

stems attached, from the same horizon and locality as the above mentioned
is identical
specimens of M. americanus. The calyx, so far as it can be seen,
with them

;

but the axial canal in the stem has three peripheral canals, instead

of four, as in the type.

Upon

genus Tripleurocrinus, with T.

this
levis,

Wood

ground alone Miss

Now

as type.

the fact that

it is

it

the

among

the

proposed for

horizon of the Devonian,
peculiar assemblage of Crinoids belonging to this
an unusual type of axial canal, there is a wide variation in the form of it,

having

not only within the same genus, but even the same species. In Cupressocrinus,
This
for example, it varies from three canals around a central one, to five.

be seen from Schultze's figures

may

—

the Eifelkalk, viz:

Taf

C. crassus

.

Monograph

in his

of the

Echinoderms of

I, figs. 1/, ?n

quadripartite.

C. iiiflatus

fig.

26

tripartite.

C. hieroglyphicus

fig.

3d

tripartite.

C. scaber

fig,

46

quadripartite.

II, fig.

6a

quadripartite.

fig.

16

quadripartite.

fig.

2c

C. abbreviatus

Taf.

C. elongatus

Taf. Ill,

C. gracilis

.

.

in the

Specimens of the same genus

in

my

collection

show variations

as follows

5 specimens quadripartite;
"
"

C. gracilis

1

C. inflatus

Furthermore,

my

present material

in the

—

2 tripartite.
7

4

from the same horizon and

and as M. americanus and

which cannot be placed

:

has produced a second quite distinct

species, doubtfully referred to SchuUzicrinus,

as the tjTie species,

"

"

3

C. sp. undescribed

canal,

and quinquepartite
same specimen.

.tri-quadri-

.

locality

T. lems, having a tripartite axial

same genus with the

latter.

In view of

these facts the genus Tripleurocrinus, having no other distinctive character

than

its

specimen, which

I

have figured on Plate

unknown.

They

I

see nothing in the

III, figs. 10a, 6, to distinguish

Myrtillocrinus americanus, of which, however,
hitherto

and

three peripheral canals, cannot be upheld;

it

by the

from

arm

characters,

facets,

apparently

furnishes the

are heavy, as indicated

it

simple throughout, and composed of brachials rather shorter than wide.

A

fact of

no small interest prevailing throughout

this grouj) of genera, is

the perforation of the radials and arms by a dorsal canal,

prevalent in the Recent Crinoids, but not found in
It

— a feature which

many

is

of the Palaeozoic.

was strongly developed among the Devonian Inadunata, appearing

in several


FOSSIL CRINOIDS.
Prof. E. J.

other genera.

127

of Toronto, in 1882

Chapman,

but

this the basis of a general classification of the Crinoids;

among

the

fossils,

Another

owing to the uncertainty of the facts

fact to be noted

is

undertook to make

in so

it is

unavailable

forms.

many

the frequent presence in these genera with very

ponderous arms, of a short first primibrach, often very much shorter than any
succeeding ones. This is very marked in Schultzicrinus, and also in Cupressocrinus

and Petalocrinus.

The mutual
as follows: —

relations of the genera

composing

;

base undivided

Anal opening

group

may

be expressed

the Genera.

Analysis of
Dicyclic

this

radials perforate.

;

through dorsal cup

lateral

Central axial canal, with

3, 4,

or 5 peripherals.

Arms branching more than once

Arachnocrinus.

Arm

Schultzia-inus.

simple, abutting, with long brachials

Arms unknown, probably

simple, divergent,

and

with short brachials

Only 4 arm-bearing
"

3

"

Gasterocoma.

Nanocrinus.

radials

"

"

Scoliocrinus.

Axial canal simple, without peripherals

Achradocrinus.

Anal opening not through dorsal cup
Central axial canal, with 3 or 4 peripherals

Myrlillocrinus.

Arachnocrinus Meek and Worthen.
1866.

Geol. Surv.

1879.

Wachsmuth and Springer, Rev.

1896.

Zittel-Eastman, Text-book Pal., 156.
Bather, Lankester's Treatise on Zool.,

1900.

Illinois,

II,

177.
Pal., I, 92.

Ill, 175.

This genus has never been well illustrated. Hall's figures of Cyathocrinus
bulbosus being the only ones published,

and they
The two

most important characters of the calyx.
smuth and Springer have never been figured
specimen by Rowley

in

Greene (Contr. Ind.

the type specimens, and nearly
of the Ohio, I

am

all

at

Pal.

all,

entirely failed to

show the

species described

by Wach-

save for one non-instructive

XVIII,

PI.

LIV,

fig. 1).

Having

the others that have been found at the Falls

in position to illustrate these species intelligibly;

and some

newly discovered material, in addition to such of the types as can be found,
makes the same possible for the New York species. These are all that are

FOSSIL CRINOIDS.

128

known

Meek and Worthen's

referable to the genus.

reference to

latus, referred to it

by Wachsmuth and Springer,

in the original generic description that there

by an anal

plate,

must

fall, in

view of what

is

is

is

of

Roemer's

was erroneous,

Poteriocrinus pisiformis, from the Sikirian of Tennessee,
species belongs to the Flexible genus Lecanocrinus

it

as that

while Cyathocrinus granu-

;

a Gissocrinus.

The statement

a lateral anal tube, supported

now known.

Revised Generic Diagnosis.

Calyx small, compared with the relatively heavy arms. Infrabasals unAnus directly through the dorsal cup, below level of arm bases.
divided.
Radial facets horseshoe-shaped, deep, concave, occupying only part of width

outward; perforated by dorsal canal passing into the

of plate, usually directed

Arms

arms.

uniserial,

Pinnules absent.
Genotype.

branching frequently, with a

fairly regular

Column round.

Arachnocrinus bulbosus (Hall).

Distribution.

America.

Middle Devonian.

Arachnocrinus bulbosus
Plate II,

figs.

(Hall).

3-12.

1866.

Cyathocrinus bulbosus Hall. 15th Rep. N. Y. St. Cab., 123, PI. I, figs. 19-22.
Arachnocrinus buibosus Meek and Worthen, Geol. Surv. 111. II, 177.

1879.

Wachsmuth and Springer, Rev.

I860.

dichotomy.

Type of the genus.

A

Pal.,

I,

93.

rather small species, with small, globose calyx and

ponderous arms; distinguished at once by the great

size of its axillary brachials,

which are several times as large as the others, extending throughout the rays,
measure
giving them a very unusual appearance; average ordinary brachials
1

mm.

high by 3 wide, while the axillaries next to them are 3

Arms

ulating facet on radials facing obliquely outward.

with frequent bifurcations,

1.

five

ant.

—
—

specimens as follows
1.

little

post.

:

in

—

r.

post.

long,

taper to the fourth

Primibrachs very irregular

the farthest preserved.

shown by

and very

mm. by 4.5.

r.

Artic-

cylindrical,

bifurcation,

number, from 3 to 12;

ant.

9

7+

6

3

3

3

5

7+

5

8

3

4

—

—

15

5

3

10

ant.

—
—
12

—
12-1-


FOSSIL CRINOIDS.

The

1

Dor-

anterior ray probably bifurcates higher than the others, as a rule.

extending throughout the arms (Fig.

sal canal

the distal end of the injured arms).

where

12,

it

may

29

be seen toward

Ventral furrow broad, roofed by two inter-

locking rows of covering plates, about 3 pairs to the ordinary brachial and 9 or

10 pairs to an axillary (Figs. 8 and

9,

showing the plates and

their sockets).

Infrabasal disk small, with obtusely quadrangular column facet, central axial

and usually four smaller ones surrounding it. Anus relatively small,
and so far as observed not followed by any plate between the radials; Fig. 6a
canal,

looks as

there might have been one, but this

if

Column with

displaced.

shown by

is

not certain, as the plates are

highly projecting nodals and long internodes, as well

Surface smooth.

Fig. ob.

Horizon and Locality.

In rocks of the Onondaga formation, near Le Roy,

New

York, associated with Myrtillocrinus and Schultzi-

Livingston county.
crinus;

The
it is

has not been found outside of that region.

it

calyx plates of this species are

fairlj' thick,'

but

beautiful specimen figured at 5a,

Museum

at Albany, as

free shale,

on one.

men
same
in

American

collection,

is

relief

it

Natural History,

New

my

is

State

a thin piece of

stem showing

York; Fig.

3,

speci-

from the

the only one of Hall's types that can be identified, and

it is

and apparently abnormal. The other
the fruit of two seasons' careful searching

caljTc,

collection,

by Mr. Kirk.

Plate

A

in

is

from an equally characteristic and well preserved
of

rare

Fig. 66

New York

sides, the

Akachnocrinus extensus Wachsmuth and

Rev.

the

II, is in

on both

how

plain enough to figure.

the former

also that of Fig. 7;

Museum

specimens figured are in
of the type region

on Plate

6,

with the calyx and arms in

Figs. 4a, h are

in the

is

poor preservation as to the

1879.

singular

to find a specimen showing the structure of the infrabasal disk;

the only one out of numerous specimens that shows

The

it is

I,

figs.

1,

2,

3,

4;

PI.

II,

figs.

Springer.
1,

2.

Pal., I, 93.

large species, perfectly distinguished

from

.4.

any special enlargement of the axillary brachials;
and wide in the lower part of the ray, about 1.5 to
surface not convex, the axillaries only larger

the divisions.

Arms

thick, round, long,

bulbosus

by the absence

of

all

brachials are very short

5,

deeply rounded but their

by the

slope necessary to start

branching three to

five times.

The

rays divide usually on about the third IBr (occasionally one or two less or more),


FOSSIL CRINOIDS.

130

except the anterior, which uniformly divides
15,

and 19 IBr

15,

much

higher up, having

9+,

13,

the halves then bifurcate

respectively in five specimens;

repeatedly at intervals of from 5 to 20 brachials on a fairly regular plan, with

minor variations; the outer branches in each dichotom continue in a definite
direction, while the others branch from them towards the inner side to the

number

of four or five bifurcations

so far as preserved,

It is

the inner ones mostly branch once or twice,

This gives from 20 to 25 ultimate divi-

and probably more.

sions to the ray, or 100 to 125 in

tapering.

;

probable that

all,

with the arms

strong and but

still

was the usual

five bifurcations

limit, as I

little

have a

specimen, not figured, with one ray five inches long extending far beyond the
fifth

and no sign

distribution

regularity in the

arm

Radial facets large, occupying

the

There

of further branching.

than in the type species.

greater part of the distal face of the plates.

and are broken and displaced
position cannot be stated, and

is

radials

quadripartite (PI.

above

it;

its

I,

position

in all

fig.
is

The

more

calyx plates are rather thin,

in all the specimens, so their exact

the base

Loose columnals are found, however, in the
canal

far

is

3).

shown

Anus

is

same

injured beyond recognition.
beds, showing that the axial

no plate between the

small, with

in Fig. 2, of Plate

I.

This species comes from strata called the Upper Helderberg

= Onondaga) by

form and

(

= Corniferous

the collectors at the type locality, the Falls of the Ohio, at

found only in the Nudeocrinus bed below the
Hydraulic bed. The type specimen was labeled by Dr. Knapp as from the
Hamilton, and so stated in the original description; but this is now known to be
erroneous, the exact horizon of all the specimens being definitely fixed as above
Louisville,

Kentucky, where

it is

principal specimens used herein are from the above

stated.

The type and

locality,

but some specimens were found

county,

New York,

(PI. I, fig. 4;

different

which apparently belong to

PI. II, fig. 2),

from that

in the

of

equivalent rocks in Livingston

it.

I

give figures of two of

them

which show the characteristic arm structure, so

A. bulbosus, with which they were associated.

Fig. 4

shows the anterior ray with about 19 brachials below the bifurcation.
Types. The magnificent specimen figured on Plate I is the type used for the
original description, then in the collection of Dr.

me some years ago together with the type
W. W. Borden, who acquired the collection.
to

of

Knapp,

of Louisville,

A. knappi, by the

and given

late Professor

This specimen seems to have

six

one being at the right posterior; on account of the broken condition of the caljrx we cannot see exactly how they start, but in the space between

rays, the extra

the right anterior ray

and the posterior interradius there must have been two


FOSSIL CRINOIDS.

131

very large one, axillary, and bearing two rays having upwards
of twenty ultimate divisions to each.
The other specimens from Louisville,
radials, or else a

and

and two others showing arm structures not
were collected by Mr. Geo. K. Greene, from whom I acquired them.
Horizon and Locality. As above stated.
PI. I, fig. 2,

PI. II, fig. 1,

Arachnocrinus knappi Wachsmuth and
Plate
Rev.

1879.

A

I,

figs.

5,

G,

figured,

Springer.

7.

Pal., I, 93.

large species, similar to A. extensus in the non-differentiaticn of the axillary

brachials (and perhaps only a variant of

greater

number

but differing from

it),

of primibrachs in all the rays.

it

in the decidedly

was founded upon a unique

It

specimen, and no others have been discovered; this has four rays preserved to

and partly to the second,
these have brachials as follows:
the

first,

1.

IBr.

IIBr.

The

bifurcation, the right posterior one being lost;

—

ant.
11

14

3-4

—

right anterior ray,

description,

is

much

r.

post.

1.

r.

post.

—
—

ant.

9

14

4-4

5

called the right posterior in the original

by oversight

smaller than the others (as rather poorly

PL

I), and was evidently recuperated, so the average number
taken from the other three, as about 13.

There are enough minor differences to make one think that
gence
in all
lar

in the condition of the rays, as contrasted

but the anterior ray of A. extensus,

it is

more

are short

like

A

and wide

—

1

to 3.6

rupted ridges or rings, which

The

is

arm

not merely sporadic.
it

facing obliquely upward.

basal disk at the

bottom

tion cannot be seen;

Anal opening very

of

in Fig. 5,

IBr should be

this great diver-

otherwise.
is

In this particu-

The primibrachs

transversely convex, and

dorsally resembles a series of inter-

not the case with any of the specimens of

radial facets are large, occupying a

The

shown

with the almost uniform 3 IBr

— and their surface

depressed at the sutures, so that the

extensus.

is

bulbosus, while wholly unlike

.

ant.

calyx

is

good

part of the plates,

^4.

and

well preserved; base concave, with infra-

of the fairly large concavity,

where

details of its condi-

basals large, rather tumid, extending well into the cavity.

large, considerably

excavated into the posterior basal, and

succeeded by an elongate triangular plate just reaching to the upper edge of
the radials.


FOSSIL CRINOIDS.

132

This species has a strong resemblance to Gasterocoma, especially
anal opening, with a

plate

above

I

it.

have given

for

comparison one of

Schultze's figures of G. antiqua with a similar plate above the anus,

around

the large

in

and others

doubtless forming the base of a small anal protuberance.

it,

The type specimen

Type.

Horizon and Locality.

the original description

is

in the author's collection.

Hamilton
to

Group, Middle Devonian.

Stated in

be from Charleston, Clark county, Indiana, on

the authority of Dr. Knapp's label; but more probably from the Beargrass
quarries, near Louisville.

SCHULTZICRINUS,
An

Inadunate,

dicyclic

Infrabasals

Crinoid.

through the dorsal cup, below level of

shaped,

gen. nov.

arm

Rays perforated by dorsal
Pinnules absent. Column rountl.

Distribution.

The name
by far the
made.
Except

directly

canal.

Arms

five,

uniserial,

Schultzicrinus typus, sp. nov.

Genotype.

is

Anus

Radial facets horseshoe-

bases.

concave.

simple.

coalesced.

is

Middle Devonian.
given in

memory

of

richest contribution to

America.

Ludwig Schultze, whose Monograph of 1866
the literature of the Devonian Crinoids ever

for the difference in arms, the

able with that of Arachnocrinus;

Synbathocrinus and Cyathocrinus.

above diagnosis would be interchange-

this difference

is

The arms continue

without bifurcation, and their component brachials are

similar to that between
directly

from the radials

and elongate, instead
In the fact of not branching they are similar to the arms of
of round and short.
Myrtillocrinus, but otherwise their structure is very different, and the lack of
an anal opening through the cup would distinguish that genus from this at once.

Schultzicrinus
Plate III,

flat

typits, sp. nov.
figs.

1-6.

Calyx rather small, depressed hemispheric, wider than high;
upper angle of basals, contracting above that.
large

and

distinct;

it.

Anus rather

posterior radials meeting above

at

Base truncate; infrabasal disk

axial canal usually quadripartite, with large central

and four smaller ones surrounding
terior basal;

widest

it,

large,

opening

encroaching on pos-

without intervening plate, so


FOSSIL CRINOIDS.
far as

known.

plate,

and directed obliquely upward.

or almost
is

Radial facets shallow,

about

almost the entire distal face of the

Arms

long and heavy, broadly rounded

abutting; brachials broad and long, except the

flat, closel}^

first,

which

ventral furrow broad and shallow, with large covering

usually very short;

plates,

filling

133

five pairs to

a plate of average

Column

Surface smooth.

size.

with very conspicuous nodals about twice the diameter of the internodals,

large,

and three or four times as long; there
of these plates, as well as the

Types.

number

is

considerable variation in the length

in the internodes.

In the author's collection.

Horizon and Locality.

Le Roy, Livingston county,

New

Near

Middle Devonian.

of the

Onondaga Group
York.

This species and genus are founded upon a series of excellent specimens,

them with more

column and arms attached, and three more
detached cups showing the base and anal opening. They show a remarkable
constancy in the characters above stated, and I have figured a thoroughly
eight of

or less of

representative selection from them.

It

is

singular that with

in getting at the basal structure of Arachnocrinus,

the infrabasal disk

specimen
is

is

larger,

(Fig. 3, PI. Ill) is

very

much

SCHULTZICRINUS
Plate III,

have figured under

going, knowing that

name
it.

larger than

for reference, in

It

deep,

it

this

may

(?)

figs.

the difficulty

was so readily found

and the exterior sutures not

not enlarged, but .shows the relative natural

I

it

all

so straight.

of the others;

any

in this;

One

the figure

size.

ELONGATUS,
7a, b,

c,

Sp.

e.

d,

name a specimen found

associated with the fore-

wanted to give it a
may throw more light upon

not belong to this genus.

hope that future discoveries

nOV.

I

has similar broad, upright, closely abutting arms, but they become narrow,

and rounded

type species,

and

ornamented with

distally

all

fine,

(compare Figs. 7e with

Differing from the

\d).

others of this group, the arms distally

sharp pustules (Fig.

7c).

The cup

is

become strongly

of a verj' different

Unforstyle from that of the others, spreading upward instead of contracting.
we
have
but
the
one
and
a
of
that
tunately
specimen,
fragment
cup
may be the

and with so much lacking in this, its real generic characters remain
obscure.
I doubt if it has the anal opening through the cup.

It will be observed
same;

that the specimen has a tripartite axial canal in the column;

been observed

in

any

of the other

American forms

and

as this

had not

of this group, except

Miss


FOSSIL CRINOIDS.

134

Wood's " Tripleurocrinus,"
is

type

I

first

but the

thought they might go together;

so diiTerent that this seems impossible, and, as ah-eady shown, too

much

importance must not be given to the form of the canal.
Type.

Author's collection.

Horizon and Locality. Onondaga Group, Le Roy, Livingston county, New York.

POTERIOCRINIDAE.
The name
number

Poteriocrinus has been applied

of species, whereas the fact

Miller in 1821,

that,

As was the case with most

belongs to but few.
J. S.

is

among authors to a very large
as genera are now understood, it

it

came

later

of the genera established

on to be taken as the type of a family,

by
and was

numerously subdivided as research became more exact and material more

plentiful.

This was done especially by

Springer in the Revision

and the genera then proposed by them, or adopted from
be carved out of the parent genus, have for the most part been accepted

of the Palaeocrinoidea
others, to

Wachsmuth and

;

by subsequent authors

as well

founded and judicious.

nizable species in Poteriocrinus proper

was reduced

The number

of recog-

from which

to thirteen,

probably two, hitherto unfigured, P. obuncus White, and P. whitei Hall, should
be removed; whi\e another Cyathocrinus macro pleurus Hall,
acteristic,

named

from the Lower Burlington Limestone, should

species,

and another

way charbe added. The last
in

every

and beautiful species from
have never been figured. The

also very characteristic

Upper Burlington Limestone, P. doris Hall,
possession of some excellent specimens for their
the

illustration,

and

of

specimens

from the Keokuk Group, herein described,
the genus and its relations.

of another very remarkable species

has suggested a brief discussion of
It

has been said with reason that Poteriocrinus

group, Poteriocrinidae, to which
Springer.

The two

its

name has been

is

not typical of the family

applied by

Wachsmuth and

leading characters which distinguish this family from the

other great family of dicyclic Inadunata, the Cyathocrinidae, are:
1.

Pinnulate arms, as against non-pinnulate.

A

and usually wide radial facet, with transverse
as against a curved and usually narrow facet.
2.

It

—

straight

fulcral ridge,

has been thought that Poteriocrinus, along with character No.

the radial facet of the Cyathocrinidae.
to this character,

an intermediate form,

This
its

is

only true in part

;

1,

it is

possessed
really, as

radial facet being small in size, occupy-

ing only a part of the distal face of the radial, and therefore

more or

less

round.

FOSSIL CRINOIDS.
but having a
is

fairly well defined

shown

distinctly

4c;

and nearly constant transverse

and

2H

to 5H).

It also

of other early species: — P.

De

Ibid., PI. I, fig. 12.

This

appears clearly in the follow-

plicatus Austin,

de Koninck and Lehon, Crin. Carb. Belg.,

id.,

ridge.

in Miller's figures of P. crassus, the type species (Nat. Hist.

Crin., opp. p. 68, figs. lA,

ing illustrations

135

Koninck's figure

10, of

Mon.,

PI. I, fig.

PI.

IX,

fig.

P. radialus,

11;

P. crassus, shows a very different

and the specimen may not belong to the genus.
The same type of articulation obtains in the three species herein

structure,

In

all

same deep

are seen the

surface character, but

is

plication of the calyx plates,

due to a folding

with modification from folds to

pits, is

which

illustrated.

not a mere

is

substance of the plates.

in the

This,

a usual, and probably constant character

in the genus.

As already

been that the genus Poteriocrinus

crinidae, has

possessing in
it

stated, one objection to the use of the family
is

not typical of

name, Poteriofamily, in not

its

the second of the characters above stated as distinguishing

full

from the largest other Inadunate family, the Cyathocrinidae,

straight radial facet.

In discussing this distinction

viz,

Wachsmuth and

a wide,
Springer

(Rev. Pal., Ill, 189-190) explained that the radials of the Cyathocrinidae have
horseshoe-like facets for the brachials;

more or

that in the Poteriocrinidae

they are

truncate along the upper margin, and united with the brachials by a

less

transverse ridge, frequently extending their entire width, accompanied
or less conspicuous fossae for muscles and ligament; the
tion existing also

upon the

same mode

by more

of articula-

that in the rays of the Cyatho-

axillary brachials;

crinidae there are, so far as observed, no muscular fossae, neither between radials

and

brachials, nor

closely

upon the axillaries; the apposed faces of all their joints fit
together, the distal end being slightly concave, the proximal to the same

extent convex.

In order to have a basis for some consideration of the possible significance
of these
it

may

two seemingly wide differences

mode

of articulation of the arms,

be well to give a description of the radial facet as

Crinoids.

Clark,

in the

who

For an accurate statement of
has

made

this I

am

it

exists in thfe living

indebted to Mr. Austin H.

these articulations the subject of special studies, based

both upon his own observations and the work of previous authors
Primarily the articular facet in
of (1) the dorsal ligament fossa;

ligament fossae;
either

and

(4)

all

:

—

groups of Recent Crinoids

(2) the transverse ridge;

is

composed

(3) the interarticular

the paired muscular fossae, these last separated by

an intermuscular ridge or an intermuscular furrow, extending usually


FOSSIL CRINOIDS.

136

to a rim or elevation about the central canal.

ligament fossa there

a more or

is

under the transverse

less

In the upper center of the dorsal

sudden depression, the ligament

may be more or less
may be seen a narrow

which

ridge,

Along the transverse ridge there
condensed, calcareous matter representing the apex of the
is

pit, just

excavated above

it.

line of transparent,

fulcra! ridge.

This

the condition in the young, and generally in adult individuals; but in

many

comes with age an increasing stiffness in the joints; the sculpture
face gradually becomes obsolete or entirely obliterated, and a plane,

species there
of the joint

or

more or

Some

curved, union of almost undifferentiated articular faces results.

less

"Actinometras" have progressed

of the

far along these lines.

obsolescence of the articular faces a curious modification

In the

often seen; with the

is

disappearance of the transverse ridge radial crenellae appear along the dorsal

margin of the dorsal ligament
of

it,

fossa,

and the transverse

what remains

ridge, or

becomes corrugated, or tuberculated.

In the Crinoids, whenever a union, through old age or otherwise, becomes
so close as to preclude motion, these crenellae always begin to form; peripheral
at

they gradually spread inward until they sometimes even reach the

first,

central canal, so that, to

mens

all

appearances they are syzygial

(Solaris

group of P. H. Carpenter)

costal" articulation;

become

it

in

young

speci-

In the genus

out.

gradations are seen in the "inter-

all

be a typical synarthry; the ligament fossae

may

or crenellae

may

may

may

Thus we

creep inward so that the joint face appears

The muscular

practically a perfect syzygy.
arthries

but

so shallow as to result in a practically flat joint face, without the longi-

tudinal ridge;

articulations, as well as the syn-

undergo a similar transformation.

see that in the living Crinoids there are a variety of stages, or con-

ditions, as to the structure of these parts,

to

made

their entirely different aspect can be readily

Comatula

;

some

which

be expected

may

or

all

of

have become established and run their courses

for

whole groups,

tological epochs.

The

fully organized joint face, as

in

palaeon-

above described, represents

a generalized type which would tend to persist, like the simple calyx of the

Inadunata, from earliest times to the present.
is

a highly specialized condition, such as,

tend to indicate a definite limitation of
tion.
will

its

if

The

undifferentiated joint face

established in a given group, would

geological range,

and

its

early extinc-

Recurring to the statement of Wachsmuth and Springer above

be seen that the two conditions, adolescent and

palaeontologically

Much

by our two

stress has

been

laid

divisions, Poteriocrinidae

upon

this

senile,

cited,

it

arc represented

and Cyathocrinidae.

matter of articulation by

many

authors,


FOSSIL CRINOIDS.
beginning with

J. S. Miller, in

1821,

who

137
very clear terms made

in not

and on account

basis of his general classification of the Crinoidea;

of

it,

it

the

at that

early day, placed his two genera, Poteriocrinus

and Cyaihocrinus, in different
Semiarticulata and Inarticulata. With an equal lack of

grand divisions,

accurate definition

it

was used by Johannes

acter of the Crinoidea Articulata

the matter clearly

when he

remained

It

and von

Mliller

for P.

Zittel as the char-

H. Carpenter to state

Stalked Crinoids, 145-6)

said (Challenger Report.

that "the name-giving difference between the Articulata and the Tessellata

reduced to a supposed difference in the mode of union of the

first

radials with

the joints which they bear."

Of

this

union there are at

least four

kinds

known among

Complete movable articulation upon wide, straight

1.

distal face of the radials;

ligaments:

Example

in fossils,

the Crinoids:
facets,

—

filling

the

with fossae, transverse ridge, paired muscles and

The adolescent type above

be found in the young of

is

all

the other types

Eupachycrinus

PoTERiocRiNiDAE

of

(PI.

and which would probably
we had specimens to examine.

described,

IV,

fig.

if

17).

Waclismuth and Springer (excepting

Poterio-

crinus — an intermediate form).

Cupressocrinus.
All

Mesozoic and Recent Crinoids

under

3).

Ordovician to Present Time.

Geological range.

with fossae, paired muscles and ligaments, but mostly

Articulation

2.

without complete transverse ridge;
plates,

(with the exceptions noted

producing a

flexible calyx

accompanying
admitting

loose suture

much

between other

mobility between apposed

and brachials, whether incorporated by interbrachial plates or
modification of No. 1, not very sharply defined. Example in fossils,

faces of radials

not:

A

Forhesiocrinus.

NoN-PiNNULATE Flexibilia, with morc or
verse ridge in some cases, as in Lecanocrinus.
Geological range.

Restricted to the Palaeozoic;

less

continuous trans-

Ordovician to Carbonif-

erous.
3.

by concavo-convex surand with round facets less than width

Articulation upon undifferentiated joint faces,

faces, usually

of the radial:

without transverse ridge,

The

thocrinus (PI. IV,

senile condition

fig.

Example

in fossils,

Cya-

12).

Cyathocrinidae
tions.

above described.

of

Wachsmuth and

.Springer,

with a few excej)-


FOSSIL CRINOIDS.

138

=

Cyathocrinoidea of Bather, plus Dendrocrinus and most of

and Botryocrinus and

allies,

Also the Non-typical
Geological range.

its allies.

Camerata

(

= Adunata

of Bather)

.

with a

Ordovician to Middle of Lower Carboniferous;

Upper Coal Measures, and perhaps

feeble reminiscence in Lecythiocrinus of the

and Hyocrinus, and

in Guettardicrinus

its

in exceptional cases

among

the Recent

Crinoids.

A

4.

immovable

close,

suture,

with

all

articular structures

obliterated, the rays being rigidly incorporated into the calyx
of solid

supplementary plates:

No.

Example

1.

A

still

more

by

completely
the growth

highly specialized derivation from

in fossils, Actinocrinus.

The Typical Camerata.
Geological range.

Referring

now

the

represents

Limited to the Palaeozoic.

only to the dicyclic Inadunata,
of

Poteriocrinidae

it

will

Wachsmuth and

be seen that plan No.
Springer,

genus Poteriocrinus as a modification in the direction of No.
completely attain the senile condition.
the earliest times,

we have

the articulation of No.

2,

Merocrinus also has wide

by the

it

presumably existed from

not the specimens to demonstrate

as

it

facets,

the

which did not

it

clearly for the

Cupulocrinus has wide, straight facets, but

Ordovician and Silurian.

joint faces are.

While

3,

including

1,

may have

has other tendencies towards the Flexibilia.

but the known specimens do not show how the

In fact this plan was for the time completely overshadowed

specializations of the other three,

which held the

field

with diminishing

—

Nos. 2
preponderance while they ran their respective courses to extinction,
and 4 within the Palaeozoic, and No. 3 practically so. As the others diminished,

No.

1

became vigorous,

as the

dominant plan

of the later Palaeozoic,

and con-

tinued to the present day.

Plan No. 3 represents substantially the Cyathocrinidae of Wachsmuth and
Springer, with their usually narrow, horseshoe facets;

it

appeared

in the earliest

Ordovician, parallel with those of the Camerata and the Flexibilia; and

it

ended,

as a morphological character of

of the

Palaeozoic.

any importance, much before the close
The latest strong genus in which it is known is Barycrinus,
reappeared in Lecythiocrinus, a rare and exceptional form

in the

Warsaw;

it

of the

Upper Coal Measures; perhaps in Hypocrinus, which is little known, even its
exact horizon; and in the Mesozoic Guettardicrinus, and the Recent Hyocrinus;
it

also tends to

appear exceptionally among the Comatulids.

In order to bring the facts of geological succession more clearly before us,


FOSSIL CRINOIDS.

139

have prepared the table on the following page showing the occurrence of the
the inquiry being
genera having these two respective types of articulation,
I

—

limited, as before stated, to the dicyclic Inadunata:

Leaving out of consideration the rare Lecythiocrinus, the
occurrence of the horseshoe facet
St. Louis),

where

in Barycrinus, in the

Warsaw

(possibly

sometimes shows the remnants of a transverse ridge

(PI.

IV,

Neither this genus, nor Cyathocrinus, nor any other with round

figs. 14, 15, 16).

facets,

it

is

latest Palaeozoic

has been found in the Kaskaskia, where Eupachycrinus and

its

congeners,

with the perfect tran.sverse articulation, flourished in profusion, and from there

up

Upper Coal Measures and Permian.
Such being the general line of succession and order

into the

any more than

to be expected that here,

we

of development,

it is

not

in the case of other characters relied

any hard and fast boundary
line separating the groups represented by plans 1 and 3, neither morphological
nor stratigraphic. The two overlapped geologically, and we may expect to find
upon as the

basis of large divisions,

shall find

intermediate stages pending the disappearance of the one and the establishment
of the other.

Thus

in Cyathocrinus,

which began

in the Silurian, there are

occasional traces of fossae, and of an imperfect, discontinuous ridge;

Barycrinus.

But these

are irregular, occurring in only a few species;

also in

and the

show no tendency to become straight, but retain the deeply concave,
rounded form, for which these genera are so well known. Perhaps the best

facets

example

of a transition

is

found

been a struggle to get rid of

round facets and a

its

in Poteriocrinus, in

specialization;

slight trace of a ridge,

it

which there seems

have

to

begins in the Devonian with

but in the Carboniferous

it

has devel-

oped a very distinct, straight ridge, within a facet that is still relatively narrow,
much less than the width of the radial. When the facet comes to fill the entire
distal face of the radial, the

form

is

called Pachylocrinus

(ohm Scaphiocrinus)

—

there being no other material difference between them, unless in the ventral sac.

But among the genera

in

which the complete articulation has become a

character there are no exceptions, or tendencies to lose

once established, the plan held absolutely, within

its

it.

When

own genera and

No.

fixed
1

was

in general,

through a long range of geological time, until the present.
In rearranging the genera of the dicyclic Inadunata under a phylogenetic
classification,

in

which morphological considerations were sent to the rear

(Lankester ZooL, III, 171), Mr. Bather thought that our great divisions into

Gyathocrinidae and Poteriocrinidae could not meet the needs of the phylogenist.

He

therefore established

two suborders, Dendrocrinoidea and Cyathocrinoidea,