natural sciences of philadelphia.

NATURAL SCIENCES OF PHILADELPHIA. 335

Eemarks

on

some

types of Carboniferous

CRINOIDEA,

with descriptions of

new

Generaand Species of the same, andofone

ECHINOID.

BY

F. B.

MEEK AND

A. H.

WORTHEN,

OftheIllinoisState GeologicalSurvey.

Sincethe publication of the second

volume

of the IllinoisGeological Re- ports, in1866,otherengagementshave,until recently,prevented us fromat- tempting

any

further investigations of the Crinoidea,

beyond

the preparation of

some

specificdescriptionsforthe thirdvolume.

On

severaloccasions

we

haveex- pressed the opinion, that theclassificationof these animals, asentireli/'based

upon

the

number and

arrangementof the pieces

composing

the walls of the

body

below the arms,withoutregard tothemostextrao?-dinan/diSevencesinotherparts,is, toaconsiderable extent,artificial;andthat

when

larger collections,containing perfectspecimens,

showing

the

whole

structure of a greater

number

of species ofvarious typescouldbeobtainedforstudy, considerable modificationsⁱⁿthe limitsofgenera, as

most

generallyunderstood,

would

befoundnecessary. Im- pressedwiththisopinion,

we

separatedinthe third vo'urae of the^IllinoisGeo- logical Reports

and

elsewhere, either as distinct genera, subgenera, or less important sections, various types that

had

alreadybeen

named by

difi'erent parties in this country

and

Europe,as distinct genera,but

which had

been almostentirelyoverlookedor neglectedby

most

authors,whileto afew other types

we

gave,forthefirsttime, distinctnames.

Having

recently

had

an opportunitytostudyinMr.

Wachsmuth's

collection at Burlington,Iowa,

what we

really believe to be

by

far the

most

extensive collection of finelypreserved Carboniferous Crinoids ever broughttogether, eitherinthiscountryorEurope,

we

have been

more

thanever impressed, not only withtheimportanceof the separations

we had

previously admitted,but withthe necessityforgivingevengreaterprominenceto

some

ofthosegroups than

we

havehithertodone, as well asfor

making

other divisions. It is only

when we

can studyagreat collectionlike this, in

which

specimens

may

becount- ed

by

hundreds,

showing

the whole structure of

numerous

speciesbelonging tovarious genera, that it can be fullyrealized

how

readily

we may

arrange

them

into perfectlynatural groups, distinguished ⁱⁿ part

by

other characters aswell asbythe structure ofthebody. In addition to this, in attempting to classifysucha collection asthisby takinginto consideration the structure of the

body

o/ily,

we

soonfindthat

we would

^oftenhavetoincludeina singlegenus formsditferingvery widely,onasimportant other characters, as thosedistin- guishing

many

of the universallyadmitted genera of othergroupsoi'Echino- dermata.

When

once

we

have

become

familiarwiththedifferentgroups, as separated

by

a careful studyof the entire structure of these animals,it is surprising to see

how

readily'

we may

generally separate them, even from veryimperfect specimens,

upon some

seemingly unimportantcharacters scarcely ever noticed

by

those

who

givethewidest limits to genera. That such divisions greatly facilitatethe studyofthesefossils

must

also be evidenttoany one

who

will attempttoidentifythe

numerous

species of

some

alliedgroups contained in a largecollection.

With

regard to the

new

species described in this paper, as well as others that

we

expecttodescribe hereafterfrom the

same

horizon, it

may

be proper to state,that

we

have

had

theadvantageofbeingableto

compare them

direct- ly (assisted

by

Mr.

Wachsmuth)

with authentic specimens of very nearly all the described speciesfromtheBurlingtonrocks.

Many

of the original typical specimens

we

havehereat

hand

inSpringfield,whileMr.

Wachsmuth

has inhis

own

collection

good

specimensof nearlyallthe described Burlington species.

Many

ofhisspecimensare alsotypes of species,while

most

of those that are not,have been identifiedfromdirectcomparison by

him and

Mr. Nilesandour-

1868.]

336 PROCEEDINGS OF THE ACADEMY OF

selves,withthe original types in the possession of others atBurlington

and

here.

The

factthat Mr.

Wachsmuth

istheonlyperson (with the exception of oc- casionalvisitors)thathasbeen collecting at Burlington duringthelast four orfiveyears,andthatduringthistimeextensive excavationshave been

made

in

working

the

numerous

quarries

and

inopening

new

streets in the Burling- ton rocks,has given

him

greatadvantagesincollecting; consequentlyhis col- lection

may now

beregarded as unrivaled in the

number

and perfection of specimens,as well asinthe

number

ofspecies.

Mr.

Wachsmuth

informsus thathealsohas

many

duplicates thatheiswill- ingtoexchangeforother Crinoids, ortodispose ofin

any way

that

may

assist inaffording

him

the

means

ofincreasinghiscollection.

Genus CYATHOCRINITES,

Miller.

As

properly restrictedto true typical species, such as theC.planus, Miller and C.mammillaris.C. calcaratusandC. bursa, Phillips,the genusCyathocrinites includesforms with a

more

orless globose (or perhapsrarelyobconic) body,

composed

of thin pieces, wliichbelowthevault consist of the basal, subradial

and

^{firstradialplates,}

and

buta single anal piece thatcan beproperly regard- edasforminga part of the walls of the

body

belowthetop of thefirstradials.

Of

true interradials there areapparentlynone.

The

baseconsistsoffivepieces, allnormallyofthe

same

form,and alternatingwith these there arefivegen- erally larger subradials, one of which, on the anal side,differsinform from the others,being truncated aboveforthe supportoftheonlyanal pieceinsert- ed between

two

of thefirstradials.

The

five first radial pieces are compara- tively large

and

alternatewiththe subradials allaround.

The

succeedingradials areallsmall,

more

orlessrounded,orsometimes an- gular,

and

always free or form no part of the walls of the body,those of each ray being distinctlyseparated by

more

orless wide interradial spaces.

The number

ofthesefree pieces varies from

two

to

some

sixorseventothe ray,the

number

beinggenerally different inthedifferentrays of the

same

in- dividual.

The arms

are slender,

more

orlessbifurcatingand roundedorsome- times angular,and always

composed

ofa singleseriesofpiecesprovided with adeep ambulacral furrow alongthe ventral orinnerside,

and

apparenth'with- out tentacula (pinnulje) along its margins.

The column

isgenerally ifnot always round

and

pierced

by

asmallcanal,

and

notdivisibleintofivesections longitudinally.

Tlievaultin thisgenusisalways

much

depressed,neverbeingextended up-

ward

intheform of alargeporiferous trunk, or so-called proboscis, as

we

see inthe typicalformsofPoteriocrinus. It isveryrarelypreservedinthespecimens as usually found,but accordingtoPhillips'andAustin'sfiguresof C.plafiusit

would

appeartobeprovidedwith alateralproboscis,or,

more

properly as

we

think, anal tube and an apparentcentral oral aperture.

From

specimensofC.

malvaceits and C. lowensis, however,

which we

havehad an opportunityto ex-

amine

in Mr.

Wachsmuth's

collectionand havedescribedinanotherplace,

we

are satisfied that, in these speciesat least,

which

appear to be typical

exam-

plesof the genus, theapparentcentralopeningisclosed byvaultpieces, inper- fectsjiecimens. Thesecentralpieces,however,are

more

liabletobe

removed by any

accidentthan thefivelargersurroundingpieces,becausethelatterare

more

deeply inserted,in ordertopermitthefiverather largeambulacral canals, extending inward from the

arm

bases,to pass over them, orrather alongthe upperside of the suturesbetween them, whilethese furrowspassinimder the pieces forming the centre of the vault,

which

are consequently less firmly fixed.

As we

have not

had

an opportunity to

examine

the original typical speci-

mens

ofC.planus, figured by^Phillipsand Austin,

we

of coursecannotassert positively that the vault of these types

was

constructedlike that of the

Iowa

species

we

havedescribed,but

we

are strongly inclined to believe such

was

[Dec.

NATURAL SCIENCES OF PHILADELPHIA. 337

really thecase,

and

that the apparent central opening

was

closed by vault pieces

when

thespecimen

was

entire.

Of

the

American

speciespresenting, sofaras

known,

the characters ofthis genusasproperlyrestricted,the followingexamples

maybt

^mentioned,

^though

the vault of only thefirst

two

ofthese speciesisyet

known

to us,^viz., C.mal- vaceus,Hall,C.Iowensis,0\ven

and Shumard,

C.[Poleriocrinus) Barrisii, C.vimi- nalis, C.lamellosus, C, divaricatus

and

C. rotundatus, Hall; also C. Saffordi

and

perhaps C.Farleyi,M.

and

W.,

and

C.riffidus,White.

N'ew species.

Cyathocrimites fragilis,M.

and W.

Body

subsphffiroidal, alittleoblique,ratherregularlyrounded tothe

column

below, fromnear the middle,andalittlecontracted above;

composed

ofremar- kablythinplates. Facetfortheattachmentofthe

column

notexcavatedand very small. Base havingthe form of a veryshallow,subpentagonal basin; basal ])ieceswitha general subquadrangularform, but really pentagonal,from the slight truncation of their smaller innerendsattheirconnection withthecolumn.

Subradial pieces comparativelylarge, hexagonal, excepting the one on the analside,

which

islarger than the others and heptagonal in outline. First radial pieces rather smallerthanthe largest subradials,

somewhat

wider than high,witha generalsubpentagonal form; allstronglyincurvedabove between thefreeradials; facet forthereception of thesecond radials about one-third thebreadthof thefirstradials

and

ratherdeeplyexcavated. Analpiecerather smaller than thefirstradials,longerthanwide, irregularlyhexagonal

and

sup- porting the outersideof theventral tube (proboscis),which,likethebody,is

composed

of very thin plates.

Second

(first free) radials very small, short

and

notalways extending entirelyacross the excavation for their reception;

succeedingradials,exceptingthelast,quadrangular,asviewed onthe outside, abouttwice aswideaslong,

and

abruptly rounded or subangular ontheout- side; lastone pentagonal

and

generally alittle longer than the others.

Of

thesefreeradialsfour

may

becountedinone of the posterior rays, six inthe other,threeinoneof thelateralrays,

and

sevenin the anteriorray.

Arms

at theiroriginonthe last radialsrather divergent, and in oneofthe posterior rays seen to bifurcateonthe sixth piece,above Avhich one ofthe divisionscan betracedto the sixth piecewithout farther bifurcation,

though

there areprobablyother divisions

beyond

;

arm

pieces aboutaslongas wide, and, like those of the free radials, all deeper than wide,

and

pi'ofoundly grooved withinforthe reception of the ambulacralorgans. Surface

smooth

oronlyveryfinely granular.

Heightofbody, 0-50 inch: greatestbreadthofsame, about0-75 inch.

Thisspeciesis related to C. rotimdattis,Hall, but not only differsin having

itsfreeradialseries

much

stouter(judgingfrom the facetsfortheir reception inthetj-picalspecimenof that species

now

beforeus), butinhavingall ofits

body

platesverydecidedlythinner,while its firstradials also diifer incurving strongly inward,between thebases of thefree rays. It likewise

comes

from thelower division of the Burlington beds, while the rotundatus

came

from the upper,

and

ithas been foundthatscarcely

any

of the species are

common

to thosetwohorizons.

Localitfiandposition.

—

Burlington,

Iowa

;lowerpart ofBurlingtonlimestone.

Mr.

Wachsmuth's

collection.

Cyathocrinites tenuidactylus,M.and

W.

Body,exclusive of the free rays, deeply cup-shaped,

rounded

below,

com-

posed of moderatelythick plates for a true Cyathocritius.

Column

compara- tivelyratherstout,

composed

nearthe baseof alternately thin and

somewhat

thickerpieces,thelatter of

which

projectalittle

and seem

to

show

a slight tendencyto

become

minutely nodular; central canal distinctlypeiitapetalous intheform of its cross section. Base

unknown

(being accidentally shoved

1868.]

338 PROCEEDINGS OF THE ACADEMY OF

into the

body

withtheend of the

column

in the specimen studied). Subra- dialsofmoderate size,those seen hexagonal. First radials

somewhat

larger thanthe subradials, alittle wider than long,with a general subpentagonal form; facet forthe reception of thesecondradialsabout one-third aswide as theuppersideof the plateand excavated about one-third of the

way

down.

Second

radial piecesvery small,wider thanlong,

and

withthesucceeding ra- dialscurving outward. Thirdradial inoneof the rays nearlyaslongaswide, expanded above andcontracted below,

and

inthisray

surmounted

bya fourth, which,likethe thirdineach of theonly

two

other rays seen,is a triangular axillarypiece,on

which

thearmsrest,theupperanglebeingacute

and

so pro- ducedasentirelyto separate thearm-bases, while thelateralslopes,on

which

thearms rest,are distinctlyconcave. Analpiece

unknown.

Arms

distinctlydivergent at their originonthe lastradials, as wellas at theirsucceeding bifurcations,dividing on the third piece in

two

of the rays seen,

and

onthefourthinanother, the piecesbeingrounded,nearly aswideas long,

somewhat

constricted in the middle

and

alittledilated at theirupper ends, whileallof the axillary piecesatthevarious bifurcationshave

much

the

same

form asthe last free radials.

Beyond

the first bifurcations mentioned, abovethelast free radials, several of thearms are seentobifurcateagain on thefifth piece

and

twicetothreetimes

more

at various distances above, while theyallgraduallydecreaseinthickness with each bifurcation until they be-

come much

attenuated,though the pieces of

which

they are

composed

main- taintheirlengthto suchadegreethat those of the smaller divisions are near- lytwice aslongaswide.

Surface of

body

plates slightly beveled at the sutures

and more

or less roughened

by

small ridges or nodes,

which

on the subradial pieces present the appearance of nearly continuous, radiating,

somewhat

nodulous ridges, whilethose of thefirstradialshave

more

the character of irregularly disposed nodes.

Length of

body below

the top of first radialpieces,0-40 inch; breadth of

same

aijout 0-64inch; length ofarms fromtheirorigin on the lastradials at least 2 inches

and

perhapsalittlemore.

This species seems to be

more

nearly allied to specimensin Mr.

Wachs-

muth'scollection thathave beenidentifiedwithPoteriocrinusBarrisi,Hall,than to

any

otherform with which

we

are acquainted. Itdiffersentirely,however, initssculpturing, that specieshavingits

body

plates

marked

with numerous, ratherfine, thread-like,radiatingcostte.

The

arms, however,are

more

similar tothose ofourspecies,though theyarerather stouterbelowin thelatter.

We

havenot

had

an opportunityto see thetype of Poteriocrinus Barrisi,but the form in Mr.

Wachsmuth's

collection,referred to that species

by

all the Burlington Geologists,isa true Cyathocrimis, or

more

properlyCyathocrinites.

Localityandposition.

— Lower

division of theBurlington beds

(Lower

Carbo- niferous)atBurlington,loAva. Mr.

Wachsmuth's

collection.

Genus BARYCRLNUS, Wachsmuth,

MS.

(finpug-,heavy; zo/Vnv,alily; inallusiontothe ponderous nature of the plates

and

arms.)

Amongst

the various

American

Carboniferous species that have been re- ferredbydifferentauthorsto thegenus Cyathocrinus,there is agroup of spe- cieswhich,although agreeing withthatgenus almostexactlyinthe

number and

arrangementofthe pieces

composing

thebody belowthe top of thefirstradials, that still differs in several rather strongly-marked characters. In the first place,these species areall

more

robust,*and havedistinctlythicker

and more

ponderous plates

and

arms thaninthe typical formsof Cyathocrinus.

They

alsodiffer ingenerallyhavinga

more

orless developed,quadrangular subanal

*

Some

ofthera attainthe giganticsizeofmorethan^3-25inchesinbreadthofbody.

[Dec.

NATURAL SCIENCES OF PHILADELPHIA. 339

piece,insertedobliquel}'under oneside of thefirstradialof the right posterior ray,and connecting with the onlyother anal piece above bya short oblique truncation of itsrightlower margin. This subaualpiece variesinitspropor- tional size,evenin difierentindividuals of the

same

species,

and

is sometimes very small, or even occasionally wanting,while it is very rarely, if ever, large

enough

to separate the first radial

and

the true anal piece above entirelyfrom eachother.

A more

constantdifference,however,istheuniform presenceofbut

two

of thefreeprimary^radial piecestoeach ray (instead ofan irregular number), excepting perhaps sometimes in the anterior ray,

where

there

may

beoneor

two

more. Thesefreeradials are also proportionallywider

and

shorter thaninthe typical forms of Cyathocrinus, particularly the second radial,

which

isoften so short

and

wide as to present a nearly transversely linearappearance,as seenonthe outerside.

As

in Cyathocrinus,the species of this group have their arms andall their divisions

composed

each ofa single seriesof pieces,apparently without pin-

nuhe

; but here these pieces are alwaj's very

much

stouter,distincth*rounded,

and

onlyprovided withcomparativelj'very small, oralmostlinearambulacral furrows. Again, theypresent

marked

differencesintheir

method

of division.

Thatis,instead of regularlydichotomizing, so astoform equal divisions

more

orlessfrequently subdividingin the

same

way,the subdivisions regularlydi- minishinginthickness,they are oftensimple fromtheirorigin onthelast ra- dials,and merelygiveoffalongtheirinnerlateralmargins,atregularintervals, alternatelyonoppositesides,stout,rounded, simplearmlets. In

some

instances one

arm

ofeach lateral ray,

and

sometimes one ofeach posteriorray,dichoto- mizes onceoroftener,but evenin these cases the other

arms

remain simple, and,likethe principalbranchesof those that bifurcate,merelythrowoffalter- nately,atregular intervalsalongtheirinnerlateralmargins,stout armlets. If these armletsinthis group performed the

same

offices as pinnulaj in other Crinoids, as

we

haveeverj'reason tobelieve theultimate subdivisions of the

arms

in Cyathocrinuaproperdid, the sacks for the reception ofthe ova

must

have protruded considerably

beyond

theedges ofthemerelylinearambulacral furrows.

In the

column

of Barycrimis

we

alsoobserve

some more

orlessdefineddiffer- encesfromthat of Cyathocrinus. For instance,in theformer group^itis pro- portionality stouter, with a

much

larger canal,

which

is also rarely,ifever, perfectlyround, but apparentlyalwaysobtuselysubpentagonal.

But

the

most

remarkabledifference consistsinits being often divisible longitudinally into five sections inBarycrinus. This character is notalways wellmarked, being apparently sometimes obliterated by the sutures

becoming

anchylosed. In

some

cases,however,it is so strongly defined that

we

find the

column

with thesesutures

more

orlessseparated alongitsentire length,

and

in

some

spe- ciestherewere apparentlypores passing through these suturestotlie cavity within.

We

areawarethat several othertypes of Crinoids

had

the

column

in this

way

divisibleintofive parts longitudinally,but

we

have notseen

any

in- dicationsofitinthe typicalformsofthegenus Cyathocrinus.

Inregardtothevault ofthis group nothing^is

known,

nota single individual of the

numerous

specimens belongingto various species hithertofound,

show-

ing,sofaras

we

areaware,

any

tracesof it.

From

thisveryfact, however,it

seems probable thatitsvaultdiffered fromthat of Cyathocrinusproperinbeing merelya softventral disc, without any covering of calcareous plates. If it

had

possessed the

power

of secreting vaultpieces,itseemsprobable,from the thickponderous natureofall itsotherparts,thatthese

would

have beensuffi- ciently firmtohave been found in place, in

some

of the

numerous

specimens

now known.

In additionto this,theupperinneredgesof thefirstradialpieces, on eachside ofthefree radials,arebeveledofftoan obtuseedge,

and show

no facetsfortheattachmentof vaultpieces.

Whatever may

bethought inregard to thisgroup being entitled torankas adistinctgenus, orasasubgenus, from Cyathocrinus,

we

canonly say that the

1868.]

340 PROCEEDINGS OF THE ACADEMY OF

various species of the

two

groups can be as readilyseparated,even without specimens

showing

thearms, as those ofanyother

two

alliedgenera. Indeed, they can be far

more

readilyseparated than Scaphiocrinus

and

Zeacrinus, or thantheformer can inall cases be separatedfrom Poteriocrinus.

Believing thata systematicclassificationofthe Crinoidea really requiresthe separation of thegroup underconsiderationfromthetypesfor

which

the

name

CyathocrinusAvas originally proposed,

we

cheerfully adopt for it Mr.

Wach-

smuth'sappropriate manuscript name,Barycrinus. Mr.

Wachsmuth

refers to thisgroup thefollowing species,the firstof

which

heregards as the typical form,

—

^viz.: B.spurius, B.crassibrachiatus, B. huUatus, B. tumidus,B.vtagister, B. Hoveyi,B.latua, B.Lyoni, B.sculptilis,B.Thomne

and

B.protuberatis,allde- scribedbyProf.Hallunderthe

name

Cyathocrinus; alsoB.cornutus[zz=Cyatho- crinus cornutus,

Owen and Shumard).

We

likewise placein thisgroup ourB. Wachsmuifn, B.angulatus

and

B. sub- tumidus, allof

which

were originallydescribed byusunderthe

name

Cyatho- crinus. It is possible our Cyathocrinus? Sangamonens

may

belong here, asit

hasthe

same

thick

body

plates,as well asthesmall quadrangularintercalated subanalpiece. Still,asall its first radial pieces are evenlytruncated, their entirebreadthstraight across above,

and

provided witha transversefurrow, as ifforthearticulationof thesecondradials,itisprobablethese

and

thesucceed- ing radials and

arms

(which are

unknown)

had a different structure

and

arrangement. It iscertainlynot a true Cyathocrinus,however,asproperlyre- stricted, but

more

probably belongstoan undescribedgenus.

Barycrinus

magnificcs, M. and.

W.

Body

attaininga giganticsize,cup-shaped, orwideningrather rapidly,with moderatelyconvex sidesfromthe

column

tothe.top of thefirstradials. Base shallow,basin-shaped, oraboutfour

and

a half times aswide ashigh,with a largeconcavefacet forthe attachmentof the column, and alarge, obscurely five-lobedperforationforthe connectionof the central cavity of the

column

withthevisceral cavity of thebody. Basalpieces regularlypentagonal.

Sub-

radial plates about five or sixtimes as large as the basal pieces,aswideas long or slightly wider, all regularlyhexagonal, excepting one on the anal side,

which

isalittle shorterthan the others,

and

truncatedaboveforthe re- ception of the anal piece, so asto present a generalheptagonaloutline. First radialpiecesaboutone- third wider thanhigh,

and

larger (particularlywider) thanthesultradials, each presenting a general pentagonal outline,

and

pro- vided witha rather shallow,outward sloping,concave facet,occupying

more

thanone-thirditsentirebreadth,forthe reception of the succeeding radials.

Second

radial piecesvery

much

smallerthanthe first,extremelyshort,oronly about one-fourth aslonginthemiddleas wide,

and becoming much

^thinner,

orwedge-shaped, on each side. Thirdradialsalittlelongerinproportion to their breadth thanthesecond,

and

presentinga subtrigonaloutline,supporting on their sloping upper sides, broad, short, rounded arm-pieces.

Anal

piece about half as wide,

and

nearly of the

same

length as the first radials,

and

subquadrangularinform. Surface

marked

with small pustules,

which

oftep

become

confluent, so as to producea peculiar corrugated roughness, some-

what

similar to the ornamentation

we

^see on the bod}' plates of the true Amphoracrinus, but^coarser.

Breadthofbody3-33 inches;heightofdo.,2-20 inches; breadthof base, 0-60 inch; breadthof facetforthe reception of the column,0-85 inch; do.of largest firstradial piece, 1-70 inches; height ofsame, 1-30 inches. Thickness ofone of thearmsatbase, 0-70inch.

This splendidCrinoid

was

found byMr. Green,of theIllinoisSurvey,with

itsplates detached

and

lyingnear together inthe rather soft matrix. After

working

outthepieces,

we

succeeded in building up the entire

body

tothe third radials

and

first arm-pieces, inclusive, excepting the anal piece,

which

was

not found. Itpresents a very strikingappearance, andisthe largest Cri-

[Dec.

NATURAL SCIENCES OF PHILADELPHIA. 341

noid

we

haveever seen. If its

arms

were as long in proportion as those of

some

other species ofthisgroup,they

must

have been near twelve inches in length,

and

withits column,body

and

arms together,^it

may

have been

more

thanfour feet in height. It is evidently related to Barycrinusmagister, Hall (sp.),butdiffersfromthatspecies,thetype of

which

is

now

beforeus, inhaving

itssurfaceroughened by

numerous

small pustules,

showing

atendencyto run together intovermicular markings, with an obscure effort, on

some

of the plates, to

assume

a radiatingarrangement. It istrue,the typicalspecimen of B.magister consists ofonly the basal pieces

and

aportion of thecolumn, but these basal plates

show

notracesof the peculiar surface markingsseen even

on

the base of ourspecies,while

we

have before us, from _the

same

original locality', anotherspecimenofthat species,consisting of the

whole

body,in a flattened

and

crushedcondition, and,althoughthe surface ofitsplates iswell- preserved,they

show

noindicationswhateverof the surfacemarkingsseen on ourspecies.

Those

who

give awide latitude to generawill probably not regard such formsasthisasbeinggenerically distinctfromCyathocrinus; even ifthatview shouldultimatelyprevail,however,

we

should insist

upon

theirseparation as a strongly

marked

subgenus,and continuetowrite the

name

of our species Cyathocrinites[Barycrinus)magnificus.

Localityandposition.

—

Hendersoncounty, nearBiggsville,Illinois; from the

Keokuk

groupof the

Lower

Carboniferous.

Barycrinus

Hoveyi,var. Herculeus.

Amongst

other Crinoids from Grawfordsville,Indiana,

we

have beforeus severalverylarge, fine specimens, agreeingwellwith Prof.Hall'sdescription ofhis Cyathocrinus Hoveyi(Bost.Jour. Nat.Hist. vol. vii,p. 293),exceptingin

some

importantpoints in the structure of the arms.

We

suspect that these specimens arespecifically distinct,butas neither

any

measurement, norfigures of the

C

Hoveyi,havej'etbeenpublished,

we

cannotfeelquite sure ofthis,

and

therefore place them,provisionally, as a variety of the species Hoveyi, under the

name

Herculeus,

which we

proposetoretainforthe speciesifthe differences to benotedarefoundtobeconstant,

and

ofspecificvalue.

The

differencesto

which we

allude are the following: InC.Hoveyithearms of the antero-lateral rays are saidto "have the anterior division twice bifur- cating,above

which

the divisions give off branchlets,

and

the

same

feature

marks

the entirelength of thelateral

arm

of the antero-lateral ray,

which

is smallerthanthe other." Inthespecimens beforeus,theanteriorlateral rays have eachthe.posteriordivision bifurcatingoncenearthe base, whilethe ante- rior divisionissimple,

and

larger,instead of smaller, than the other. Again, theHoveyiissaid tohave," inthe postero-lateral arms, thelateraldivision of therays bifurcatingonthe fourth piece, above which branchlets are

thrown

off,asin the others." In thespecimens beforeus, however,both

arms

of the posteriorraysare, likethose of the anterior ray,

and

oneof each lateral(or anteriorlateral) rays,simplefromtheir originonthe thirdradials,verylong, stout,

and

give offalongtheir inner lateral margins stout,simple armlets,al- ternatelyatregularintervals.

As we

haveseen severalspecimensall agreeing in these characters,

we

are inclinedtothink this

may

be aspecific difference.

Inoneof thespecimens before us the

body

measures ^1-10 inches from the baseto the top of thefirstradials,

and

about 1-4Uinchesinbreadth.

The arms show

a length of 4 inches,

and

arebrokenatthe ends, so astoappearto have been,

when

entire, nearly one inch longer.

They

are verystraight,nearly cylindrical,

and

measure 0-22 inchindiameter nearthemiddle,

where

each

arm-

piecemeasures about0"15 inchin length,

and

the lateral armlets nearly the

same

indiameter.

Genus NIPTEROCRINUS, Wachsmuth, MS.

{xiTrryifi,a

washing

vessel; k/x'vov,alily; inallusion toits basin-shaped body.) Mr.

Wachsmuth

has proposed the above name,in manuscript, for atype

1868.]

842 PROCEEDINGS OP THE ACADEMY OP

agreeing with Ci/athocrinusproperinthe thinness ofits

body

plates, inthena- ture of thebifurcations ofitsarms,and apparently inthe general structure of itsbody,exceptingthatithasnoanalplate,thefirstradials beinglarge,wide,

and

incontact all around,so as to leave no spaces for anal or interradial pieces.

The

succeeding radials after the first are comparativelysmall,

and number

from threetofour(so farasyet

known)

toeach ray,the first always restinginrounded sinuses intheupper edgeof the largefirst i-adials,

much

as inCyathocrinus, exceptingthat thesefreeradialsareveryshort,

more

as

we

^see

inBarycrinus.

They

differ, however, fromthose ofboth Ci/athocrinus

and Ba-

rya-inus, ineach having itslower edge alongthe outer side of the arms pro- duced

downward,

into acorresponding sinus in tlieupperouteredge of each succeedingpiece below, so astopresent

much

theappearanceseen inthe

arms

of Taxocrinus, Onyc/wcrinusandForbesiocrimis,exceptingthat theproducedpart does not seem to be separate patelliform pieces,but merely the

downward

produced lowerouteredgeofeach arm-pieceitself.

None

of thespecimensyetfound

show

thenumberofbasalpieces,but

we

can see thatitsbodyis

composed

of small basals,witli fivewell-developedsubra- dials ofuniform shape,

and

fivelargefirstradials. This structure of thebody,

it willbeseen, is exactly that ofErisocrinus,

—

thatisif thebase is

composed

offive pieces,

which

isvery probable.

The whole

structure

and

aspect of the parts above,however,is entirely different inthesegroups, sincein Krisocrinas there are alwaj-s but

two

primary^radial pieces to each ray,while thesecond radials are as large as thefirst,

and

instead of merelyrestingin small sinuses intheupper part of the latter,the

two

articulatetogether bystraight edges acrosstheir entirebreadth, the articulating edges being always provided with a crenated transverse ridge

and

furrows.

The arms

of Ensocrhius are also

much

stouter,

and

presentnone oftlie characters of the typeunderconsidera- tion, whileallofits

body and arm

pieces alsodiffer in beingverythick.

It isaninterestingfactthatthe

column

of thegenushere described, as well as itsarms, present a striking similaritytothat ofTaxocrinus

and

alliedgroups, beinground, and

composed

nearthebodyofexceedingly thinpieces, connect- ing by crenate surfaces,

and

provided with a comparatively small central canal. Notwithstanding these points of resemblance, however,to Taxocrinus, it is evident thatthisgroup is

more

nearlyallied to Cyathocrinus. Ifithas,as seemstobe the case, fivebasal pieces, theformulaof the genus

would

be as follows

:

Basal pieces5; subradials5,allof the

same

form; radials 4to 5

X

^5,the

firstbeinglarge

and

formingthe larger partofthebody,the others small

and

free; anals ;interradials ;

arms

bifurcating,

and

resemblingthose ofTaxo- crinus.

Some

fiveorsixspecimens ofthis type

show

that theabsenceof anal pieces isnotan abnormal, butaconstant character.

NiPTEROCRiNus

Wachsmuthi, M. and W.

Body

rather deeply basin-shaped, or a little

more

than twice as wide as high, rounding under from the top of the first radials to the column.

Base small, fiat,

and

nearly hidden

by

the column. Subradial pieces of moderate size,

somewhat

wider than long,

and

all pentagonal, there being no visibleangle at themiddle of theunder sideofanyof tlicni. First radialscomparativelyverylarge, oraboutthree times thesize of the subradi- als,twice aswideashigli.

and

all alike pentagonal; while each is provided witharatherdeep roundedsinusabove,equalingaboutone-third ofitsbreadth, forthe reception of the succeeding radials,on each side of

which

its upper

margin

is nearlystraight,horizontal,

and

not incurved.

Second

radials so short as scarcelytofillthe sinusintheuppersideof thefirst,

and owing

to thecon- cave outline above, often presenting a narrowtransversely crescentic form.

Third

and

fourth radials(where there arefive) veryshort,or several times as wideaslong,

and

usually

somewhat

arcuate inversely. Last(fourth or^fifth)

[Dec.

NATURAL SCIENCES OF PHILADELPHIA. 343

radialsalittlelonger than thenext below,

and

generally trigonal or subpen- tagoaal (theupper angle being

somewhat

salient),

and

supportingthearms on

itsslopingsides.

Arms

rounded,rather divergent,

and

bifurcatingonthe sixth orseventh pieceabovetheirbases,

and

again onceor oftener farther up, the divisionsabove each bifurcation being about half as large as the

main arm

below; arm-pieces about twice as wide as long,not wedge-shaped, but all

showing

the

downward

curvaturequitedistinctly,andslightlyconstricted on eachside. Surfacemerelyfinelygranular,

and

the platesof the

body

neither bevelednortumid.

Column composed

of suchthiu pieces thataboutfifteen of thera

may

becountedina length equalingits

own

thickness,near the base.

Heightofbodyof the largestspecimentotop offirstradials,about0-43 inch

;

breadth near 1 inch.

Thickness_of

column

ofsame, nearbase, 0-20inch; diameterofitssubpen- tagonalcaual, 0-05 inch.

This Crinoidis so unlikeallothers

known

to us,thatitisscarcelynecessary to

compare

it withanyof the described forms.

The

specific

name

isgiven in honorofMr. Charles

Wachsmuth,

theauthorofthegenus,to

whom we

arein- debted fortheloan of the typical specimens.

Localityandposition.

— Upper

Burlington beds of the

Lower

Carboniferous.

Burlington,Iowa.

Mr.

Wachsmuth's

collection.

Genus CATILLOCRINUS,

Troost.

Catillocrinus Bradleyi, M.

and W.

Body

small,basin-shapedor ratherbroadly truncated belowforconnection withthecolumn,

and

moderatelyexpanding

upward

tothetop of the radials supporting the arms.

Lower

^series of platesvisible around the top of the column, anchjiosed together,

and

presenting the form of abroad lowdish

many

timeswider than high,with themargins sinuousaboveforthe reception of thenextrangeofpieces. Succeeding rangeof plates presenting the usual irregularform of thegenus,

two

of

them

being

much

larger than the others, verywide atthetop,

and

supportingnearly or quiteall ofthe

arms

; between theseononeside thereisa

much

smaller triangular pieceonthe

same

range,

and

extendingupashighasthe others,butso

narrow

at the top thatit could nothave supported

more

than oneortwo, if any, of the smallarms.

On

the opposite sidethere aretwoothersmall intercalatedpieces,thesmaller of

which

istriangular

and

scarcel^^extends upto the topof the cup,whilethe other is oblong,extendstothe top of the cup,

and

supports either another

somewhat

smaller (anal_?)pieceabove, or the base ofan

arm much

largerthanthe others.

Arms

about44, in contact at their bases,

and

all slender

and composed

of joints

two

or three times as longas wide. Surface smooth.

Column

compara- tivelyvery large (circular?), witha large round central canal,

and composed

nearthebase of rather thin pieces ofuniform size.

Heightofbody, 0-18 inch; breadthattop, 24 inch; breadth of

column

at thebase of the body, 0-13 inch.

This species will be atonce distinguished from ^('. Tetmesse.exofTroost by

its

much

smallersize,and

smooth

instead of coarselygranular plates. It is

much more

nearlyallied toour 0. Wachsmuthi,fromtheBurlington group, but .'bodyisless

expanded

atthe top,

and

it also differs in havingacompara-

tivel}^large anal?piece,or largerarm,betweentheotherson oneside.

Named

inhonorof Prof.

Frank

H. Bradley, of

Hanover

College,late of the Illinois Geological Survey,

who

discoveredtheonlyspecimen

known.

Loculiti/andposition.

—

Crawfordsville, Indiana;

Keokuk

division of

Lower

Carboniferous series.

Genus DICHOCRINUS,

Munster.

DicHOCRiNus EXPANSus, M.

and W.

Body

expandingrather rapidlyfrom thefacet fortheattachment of the col-

1868.]

344 PROCEEDINGS OF THE ACADEMY OF

umn,

tothe top of the base,

and

still

more

rapidlyfromtheretothetop of the firstradials,so as to

make

the breadth at the latter point about twice the height. Base forminglessthanhalf theheightof thebody,

somewhat

basin- shaped, though narrow below,or

ornamented

with small irregular wart-like nodes,

which show some

tendencytoform three or fourvertical rows, or ridges on eachbasalpiece. First radial piecescomparativelylarge,

somewhat

oblong inform,being longer than wide,withthewidest endabove, allconvex along

up

the middle,

and

strongly beveled, orexcavated along the sutures on each side,

—

^while the surface ofeachis

ornamented

withsmall, irregular,wart-like nodes, similar to thoseonthe base; these sometimes coalesce into irregular ridges,butare usuallyarranged inthreerows, starting fromthe

most

promi- nentupperendof theplates,

and

radiatingtothebase; facet forthereception of the secondradialpiecesaboutone-third thebreadth ofthe upperendofthe plates,

and somewhat

excavated.

Anal

piece of

much

the

same

size,

and

generalnodose appearanceasthefirstradialon eachside,but

somewhat

longer,

and

having anirregularhexagonal form.

Second

radial pieces small,about twice aswideas long,

and more

orlessquadrangularinform. Third radials slightlylargerthan the second,with a pentagonal form, the upper sloping sidessupportingthe firstdivision of thearms.

Arms

rounded,

composed

at firstof pieces aboutaslongas wide,

upon

the secondor third of wliich theybifurcate, the outer divisionsremainingsimple,

and

theinnerones bifurcating againonthesecond or third piece,the outer division,as before,remainingsimple,

and

the inner bifurcating a thirdtime

on

the secondpieces,thus

making

inthe posteriorrays (the onlyonesseen) eight armstoeachray,or fortyinthe

whole

series,ifother rayshavethe

same num-

ber. All thesimple

arms

arelong, slender, rounded,

and

butslightlytapering

;

neartheirbasestheyareeach

composed

ofa singleseriesof

somewhat wedge-

formedpieces, but graduallypass intoa doubleseriesofminute interlocking pieces.

Breadthofbody, 0-98 inch; heightabout0-43 inch. Length of one ofthe simple arms,about1-fciOinches; thickness of

same

atbase, 0-05 inch.

Associated with the specimen from

which

the foregoing description

was drawn

up, several other imperfectexampleswerefound, differing

more

or less inform

and

inthearrangementof their ornamentation,

which

eitherindicate considerable variationsin these characters, or the existence of several allied species.

One

of thesehas thefirstradial

and

anal plates

more

abruptlyspread- ing,

and

proportionallywider thaninthe typical form,whileitsnodesare

more

coalescent, so as

more

generallytorunintocontinuousribs.

On

the base,for instance, eachof the

two

plateshasthree

somewhat

nodulousvertical ridges, withinterveningrows of thelittlenodes,whilethe threerows ofnodesonthe firstradialandanal pieces oftenrun together soas to form

mere

nodulous ridges. Itispossiblethis

would

befoundtobe adistinct species,if

we

could examineaspecimen

showing

the arms. If so,it

may

be called

D.

stelliformis, inallusiontothestar-like appearance produced byits spreading first radial pieces, with theirlittleridges running

outward and

converging to the outer extremityof each.

Inanotherindividual thenodes

and

ridges areall nearly obsolete,excepting afewof the former,

which

areveryprominentatthemiddle of the outerends of thefirstradials; while another hasa single prominent node nearthe small facetineachfirstradial, forthereception of thesecond,with afew irregularly scatteringnodes onotherparts,

and

slender, obscure, nodularridgesnear the lateral margins.

From

the general appearance of these specimens,

we

are rather inclinedtothe opinion that they are^{all varieties}ofonevariablespecies.

Locality andposition.

— ^Same

^aslast.

Genus DORYORINUS, Roemer.

In thesecond

volume

of theReportsof theGeological SurveyofIllinois,

we

distinctlyrecognized theDorycrinus group as forming a well-defined genus,

[Dec.

NATITRAL SCIENCES OF PHILADELPHIA. 345

clearly separated fromActinocrinvs(as properly restricted), to

which

genus theyhavegenerallybeenreferred; but

owing

tothefact thatatthattime

we had

neverseen either aspecimenor a figure of an Amphoracrinus

showing

the arms, body,

and

parts connected with the openingof the vault,allpreserved together,

we

were underamisapprehensioninregardto the true characters of that group,and consequently placed Dorycrinusas a

synonym

under ^it. Re- cently, however,

we

have beenso fortunate asto see inMr.

Wachsmuth's

ex- tensive collection beautifulspecimensofbothtypes,ina remarkablyfine state of preservation,

and

fromthese

we

aresatisfiedthata systematic classification of the Crinoidea requires these two groupstobe separated asdistinctgenera.

In thefirst place,it

may

beproperto

remark

that inboth of these groups the structure of the body, sofaras regards the

number and

arrangement of the piecesbelowthearm-bases, isalmostexactly the

same

asinActinocrinus.*

Tliestructure of the parts above,however,isverydifi'erent. Forinstance, in Dorycrinusthe openingof the vault isneverattheendof a

more

orless pro- longedtube, or so-called proboscis,noreveninthe slightestdegree proboscidi- form,butismerelyasimpleaperture penetrating a

somewhat

thickened pro- tuberance,

and

nearly always situated

and

opening laterally.

The

vault in thisgroupisgenerallyprovided witha

more

orlessprominentspineover each ray,

and

a sixthoneinthe middle.

Sometimes

these areall,orinpart,merely representedbynodes, oreven in

some

instancesnearly obsolete,whileinothers theyare extravagantlydeveloped. Again, Dorycrinus differs from both Acti- nocrinus

and

Amphoracrinusin having, so far as yet

known,

always two arms i-pringing directly

from

each arm-opening,

and

these arms always simple.

Our

at- tention

was

first called to this byMr.

Wachsmuth, who

isavtrycareful

and

accurateobserver,

and we

found ittobesoinall thespecimensinhiscollec- tion,while he assures us thatthisis thecasein allthe specimens found bythe various collectors at Burlington, as well as all of those he hasyetseen from otherlocalities,withthe

arms

attached.

Hence

in all ofthe species of this groupdescribedbyProf.Hall

and

others,

where

the

number

of arms has been given from merely counting the arm-openings,

— ^and

^specimensof these have sincebeen observed withthe

arms

attached,

—

their

number

isfoundtohe just doublethat statedinthe descriptions. It isalso

worthy

ofnote thatin thisgroup the

body

plates are either plane,

more

or less tumid,or tuberculiform,

and

never

marked

withproperradiatingcostie,as

we

often seeinActinocrinus.

The

followingisalistof thedescribed speciesbelongingtothisgroup,allof

which

are, so far as

known,

exclusively

American

types,and confined to the

Lower

Carboniferous,viz.: DorycrinusIfississippiensis, Roemer,

and

D. Gouldi, f D. cornigerus*

D.

divaricatus*

D.

trinodus,

D.

quinquelobus*D. symmetricus*

D.

desiderattis, D.unispimis,*

and D.

subaculeati/s,Hall (sp.),^all of which were describedbyProf. Hall underthe

name

Actinocrinus. It likewise includes

D.

Missouriensis* {==Act. Missouriensis,

Shumard) and D.

unicornis*

[=

^{Act. uni-}

cornis,\

Owen and Shumard),

as well as our D.subturbinatus,* originally de- scribed asanActinocrinus.

Itmightatafirst glancebesupposed alsoto include Actinocrinuscorniculus

and

A.brevis of Hall, but these forms (which Mr.

Wachsmuth's

collections clearly

show

to be onlyvarieties of one species) have butasingle

arm

from each arm-opening (two to each ray),

and

these arms with the proportional stoutness, general structure,

and

broad pieces at their bases, of Agaricorinus.

Hence

this species can only be regardedasa

somewhat

aberrant form of the lattergenus.

To

thegenus Dorycrinus

we

alsoreferthefollowing

new

species

:

*Dorycrinus, however, differs fromActinocrinusin having the second radial pieces nearly alwaysshortandquadrangular,instead ofhexagonal.

tSpecimensofallthe species'markedwitiianasteriskhave been found withthearms attached,andpresentingthecharactersmentionedabove. The armsofthe othersremain unknown.

X^'I'heproposed species A.iricornisandA. pendens, Hall, arebelievedtobe only variedes of unicornis ofO.andS.

1868.]

23

346 PROCEEDINGS OP THE ACADEMY OF

DoRYCRiNus

RoEMERi, M.and

W.

Body somewhat

urn-shaped,being obconicalbelowthearmstothetruncated base,and moderately prominent above, the vault forming rather

more

than one-third oftlieentire height; greatestbreadthatthe arm-bases. Base trun- cated

and somewhat

concave below,abouttwice as wide as high,slightly ex- ])andedandalittleangular below,witli broad, rather shallow notchesat the sutures. First radial piecesabouttwice

and

a half aswideas high,

two

hep- tagonal

and

threehexagonal,each oneswelling out so asto formamoderately jjrominent, rather obtuse, transversely elongated node.

Second

radials one- thirdto nearlyone-half as longas the first, quadrangular,alittlewider than long, and

more

or less tumid. Third radials rather larger than the second, wider thanlong,pentagonal, hexagonal

and

heptagonal; each one supporting on each ofitssuperior sloping sidesapentagonal secondaryradial, of rather smallersize, eachof

which

inthe posterior rays supports,in itsturn,on each side above, one, orsometimestwo,brachialpieces,

making

four arm-openings toeachof theserays. Thisseemstobe the case also inthe rightlateral ray, whileoneof thesecondaryradials, inthespecimenstudied,appearstobemerely truncated, so as to support (perhaps abnormally) only one brachial piece, thus

making

onlythreearm-openingstothisray.

The

brachial

and

secondary radial pieces of the anterior ray are broken

away

in the specimen, but it is

probabletherewere fourarm-openingsinthis ray. Ifso,there

would

benine- teenarm-openings (probably normally twenty) inthe entireseries,

and

thirty- eighttofortyarms, countingtwotoeach opening.

Firstanal piece of the

same

sizeand form asthefirstradials,and,likethem, swelling out intoa transverselyelongated node.

Above

this there are

two

heptagonal,

and

one apparently hexagonal,rathertumidpieces in the second range,

and

abovethelatterseveralother piecesextendingup between^the

arm-

bases, so astoconnectwith aseriesof piecesformingathickened protuberance risingeven slightlyhigher than the

summit

of the vault,

and

pierced by the anal opening,

which

is situated considerablyabove the horizon of the arm- bases,butstill directedlaterally. Interradial pieces threeto eacharea, thefirst

beingabouthalf as large as the subradials,heptagonal or octagonal,and sup- porting

two somewhat

elongated irregularlyformed pieces that are scarcely convex,

and

connect, bytheir narrow upper ends,with vault pieces above.

Vault

somewhat

rounded,with lateralspinesveryshort,ormerely having the formof ratherprominent conical nodes; central piece

somewhat

tumid,but not evenconical.

Arms

and

column unknown.

Named

inhonorofDr. F.Roemer,thefounderof thegenus Dorycrinus.

Heightofbodytotop of vault, I-40 inches; do. totop of anal protuberance, 1-45 inch; breadthatarm-bases, 1-30 inch; breadth of base, fe-55inch.

Thisspeciesisperhaps

more

nearlyallied toD.Missouriensis,

Shumard

^(sp)

than to anyother yet

known.

Itwill be readily distinguished,however,by severalwell-marked characters. Inthefirst place,itsbase isnot thickened

and

expandedasinthatspecies. Again,itsvault isnot so flattened on top, northesi)ines, ortumid piecesover therays, near solarge. Inthe Missouri- ensisthe lattercharacterisso strongly

marked

astoplace the widest part of the

body

above the arm-bases,

which

consequentlyhave the appearance of beingattached half-way

down

thesidesofthebody,whilein the speciesunder consideration the bodyisdistinctlywider at the arm-base than above.

Our

species also hassevenor eightarms

more

thanDr.Shumard's.

Those

who

prefer to viewtheVorycnnus group as only a section of Actino-

criiiitswill, vre hope,at least write the

name

ofthisspecies Actinocrinus i^Dory- crinus')Roemeri.

Locality

and

position.

— ^Upper

part of theBurlingtonbeds, of the

Lower

Car- boniferousseries,atBurlington, Iowa. No.127 of Mr.

Wachsmuth's

collection.

DoRYCRINnS

QUINQUELOBUS, Var. INTERMEDIUS.

On comparing

thisform withthetypicalspecimenof

D.

quinquelobus [t=Acli- nocrinusquinqxielobus,Hall, Supp.

Iowa

Geol. Rei)ort, vol.i, p,15),

we

findthat

[Dec.

NATURAL SCIENCES OF PHILADELPHIA. ³⁴⁷

itagrees very closelyinthe structureofits body, as well asinthe

number

of arm-opening-3 toeachray (thatis, four tothe anterior

and

eachposteriorray,

and two

ineachofthelateralrays),butat the

same

timeitpresents

some

other differences, that

we

suspect

may

beevenof specific importance. In the first placeit islarger

and more

robust,atidhasa proportionally smaller base,

and

ratherdistinctlytumid,instead of even

body

plates, whileits interradial

and

anal spaces are notnearsodeeplyexcavated between the arm-bases^asin the type of quinquelobtM. Its third radialpieces alsodifferinform,beingsonarrow inall theraj^sasto let the secondarj' radials

come

in contactwith the first interradial

and

thesecond rangeofanalpieces, instead ofextending around so far laterallyasto separate thesepieces. Itsvaultislikewise

more

flattenedon top.

In the typicalspecimen ofD. quinguelobusthe spines of the vault have all

beenaccidentallj'removed, butin the form under consideration theyseem to

have beenshortandstout, thoughtheir entire length is not

known,

as they were apparently broken offduringthelifeof the animal, sincetheyeach have thebrokenend

somewhat

rounded

and

indentedin the middle. In size and generalappearance itis

more

likeD. MississippiensisofRoemer,butitdiffersin having rather

more

tumid

body

plates, as well as inthe

number

ofthe arm- openings, that species having four of these openings toeach rayall around.

Italsohas a

more

protuberantanal opening,

and

probably

had much

shorter vaultspines. Itthereforeseemsto be

somewhat

intermediate between the J).

Mississippiensis

and

D.quinqtielohus, but is probably distinctspecifically from

them

both.

As we

have buta single specimen, however,ofit, andthe typical specimenofD.quinquelobusforcomparison,

we

prefertoplaceit,forthe present, asa variety of that species,underthe

name

inter rnedius,

and

if itshould here- afterbefound that the differences

we

havepointedoutare constant,itcantake the

name

bj'

which we

have proposed to distinguish itas a variety, as aspe- cific name.

Localiti/andposition.

— Upper

part of the Burlington division of the

Lower

Carboniferousseries,atBurlington, Iowa. No.164 of Mr.

Wachsmuth's

col- lection.

Genus AMPHORACRINUS,

Austin.

As already stated, thisgroup agreeswith Actinocrinus in the

number and

arrangementofthe pieces

composing

theunderside of thebody,aswell asin having the parts adjacent to the arm-bases forming five projecting lobes, distinctlyseparatedfrom each other bythe anal

and

interradial sinuses. It differs from

them

both,however,inthe structure of the parts above,as well asin havingthe

body

generally

more

depressed, or even flatbelow, and the vault proportionally

more

ventricose; whileits secondradialpieces are

more

generally hexagonal than in Dorycrinus.

From

the latter it also differs in liaving theopeningofthe vault

more

orlessproboscidiform,*

and

placed nearly half

way

betweenthemiddle

and

the analside,instead ofbeinga simplegene- rally lateralaperture, penetrating laterally a merely thickened protuberance.

Tiieproboscidiformextension ofits vault,however,isneversolong

and

slen- der as

we

usually seeinActinocrinus,

and

also often differsin being

crowned

with small spinessurrounding thevery small terminal aperture,

which

seems alwaystoopen upward.

As

inDorycrinus,the*\^aultisgenerally

more

or less spiniferous, though the spines are differently arranged, and, as far as yet

known,

neversoextravagantlydevelopedas

we

sometimes see

them

in that

*Inallthe foreignspecimensof the typical species ofAmphnracrinusthatwehaveseen, onlytiiebroken baseofthissliortproboscis remains;and thisalsoseems tohavebetn the ease with nearlyallthose fromwhich the published figureswhich we have had an opportunitytoexamine,were drawn Cumberland, however, has givena tigure in his UeliqiiiajConservatte,(pi.C),apparentlyofthe typical speciesamplwra. with theshort oblique proboscis well preserved. Thiswillbe seento differmateriallyfromthemerely slightlyprotuberant thickeninginwhichtheopeninginDorycrinusissituated.

1868.]

348 PROCEEDINGS OF THE ACADEMY OF

group.

Some

of the species are

known

tohave oneof the vault pieces over eachray

more

orlessprotuberant,

and

it

may

be the case that species existed in

which

thosewere developedinto spines,

somewhat

asinDorycrimis,though

we

arenotawarethat

any

such haveyetbeenfound. Nearthemiddleof the vault thereisalsoa largetumidpiece, sometimes developedinto a short spine, while aroundthe anterior side of this,four or five similar pieces aresemi- circularly arranged,

which

also often

become

welldeveloped sjiines.

We

have neverseen anyfigures orspecimensofthe

European

typical species ofAmphoracrimis

showing

the arms,butthere arein Mr.

Wachsmuth's

collec- tionseveralbeautiful specimens, found atBurlington,agreeingexactly in all other characters (notmerelyspecific) with thetypes of thegeniis, inwhichthe

arms

are perfectlypreserved. In these

we

observe

marked

differences,both from Dorycrinus

and

Actinocrinus. For instance, in

Amphoracrmus

divergens

(=

Actinocrinusdivergens^Hall),thearms, althoughbifurcating so often asto

form

altogetheraboutfifty-three ormoredivisions,theyareeach, aswell aseachof these divisions,

composed

of adouble seriesofveryshort alternating pieces allthe

way

down, even below allthebifurcations to their very bases, with theexception of oneto

two

orthree simple brachial pieces, at the origin ofeach

main arm

on thelastprimaryorsecondaryradials.

The

structure of thearms,itwillbe seen, isthe

same

as inSaccocrinus (an otherwisedifferenttype),but widelydifferentfrom

what we

see\nActinocrinus, in

which

the

arms

are always

composed

of a singleseriesof piecesbeloio such bifurcations as take place. ^{It is}alsoeven

more

decidedlydifferentfrom that of Dorycrimis,in

which

the

arms

not onlyneverbifurcatein

any

of the speciesin

which

they are

known,

but are also arranged so that

two

of

them

spring directly from each arm-opening without impartingto the brachial piece on

which

theyrestthe usual form ofan axillary.piece.

In one species, however, [Actinocrinus spinobrachiatvs,Hall),having appa- rentlyall the other characters of Amphoracrimis,the

arms

do not bifurcate after their origin on the axillary secondary radial pieces. It seems,there- fore, probable that there are

some

species ofthis group with simplearms,

and

others that have

them more

orlessfrequently bifurcating.

The

proba- bility is, however, that in all cases

when

they do bifurcate, that they are equally

composed

of adoubleseries of small alternating pieces below thebi- furcations as well as above, the

same

as inthe speciesdivergens.

Whether we

include such species asthe spinobrachatus,however, withmerelysimple arms,

composed

likethe others of adoubleseries of alternating pieces throughout their entire length, as a separate section of Amphoracrinus, orview

them

as formingadistinct group,they need not for a

moment

be confounded with Dorycrimis,from

which

theynotonlydifferinform, surfacemarkings, opening of the vault, ^&c.,butalsoinneverhaving two

arms

springing directlyfrom each arm-opening.

Inallthe species ofAmphoracrinus

known

to us,either foreign or

Ameri-

can,itisalso

worthy

ofnote that the surface of the

body

platesisnever orna-

mented

with properradiatingcostne,such as

we

often seein Actinocrimis

and

otheralliedtypes,noryetsmooth, orproperly tuberculiform, asinDorycrinus, but alwayspresents a peculiar vermicularstyle ofsculpturing or corrugation difficult to describe, butvery characteristic

and

easilyrecognized again after being once observed.

To

this group Mr.

Wachsmuth

has,inMS., correctly referred the following

American

species, viz: Amphoracrinusdivergens, A.planobasalis, A. spino- brachiatus?

and

-4. intiatus, described byProf. Hall,under Actinocrinus; also Actinocrinus quadrispinus,

White

; allfromthelower division of the Burling- ton beds.

Amphoracrinus

divergens, Hall, (sp.) Actinocrimis divergens, Hall,Supp.

Iowa

Report,p. 36,1860.

Thisspecies

was

apparentlydescribed byProf. Hall from imperfect speci- mens,

showing

only a fewofthe lower bifurcations of the arms, since he

[Dec.