Descriptions of new Crinoidea, &c., from the Carboniferous rocks of Illinois and some of the adjoining states

NATURAL

SCIENCES OF

PHILADELPHIA.

155

prominentpart being within the middle. Aperture(as inferredfromsections ofthe whorls) transversely subreniform. Septa with asinglepointed lobeon eachside; dorsallobeinfundibuliform, thenarrow_portionbeing lanceolate;

dorsalsaddle broadlyandvery obtuselyrounded; superior^{lateral lobe}from one-fourthtoone-third largerthan the dorsal,and having

much

thesame shape, excepting that^itisproportionally wider;inferior laterallobe consisting merely^{of abroad}roundedsinuosity. (Surfaceunknown.)

Should Montfort's

name

_Aganides be retainedforthisgenus, the

name

of this specieswould becomeAganides compactus.

Greatest diameter 2-50 inches;convexity(orbreadthofaperture) 1'33 inch;

breadthofumbilicus, about 1\12^inch.

Localityand_position. Coal Measures. MacoupinCo.,^111.

Noteinregard^tothename"Cincinnati Group,"^usedintheforegoing paper.

Asit is

now

acknowledgedthat the rocks along theHudsonriver valley, to which the

name

Hudson River Group had been applied,belong, ^as long maintained by^Dr.

Emmons,

^toadifferenthorizon from theso-calledHudson River rocksofwestern

New

York,andthestates fartherwestward,^itseemsto bean awkward misnomertocontinuetoapply the

name

HudsonRiverGroup tothesewestern deposits. Hence it is certainly desirable thatthisgroup shouldreceivesomeappropriate andgenerally applicable name. Its subdi- visions,^itistrue,havealready received various lithologicalnames, such as

"

UticaSlate,""FrankfortSlate," "Lorraine Shale,"^&c.; butaseachof thesenames will probably be always directly associated, in theminds of geologists, with theparticularsubdivisiontowhichitwasoriginally applied, while neitherofthemisapplicable^tothelithologicalcharactersofthewhole series,wecannot, withoutcreatingconfusion,^soextend itssignification. ^It has recently been proposed ^todesignatethis series asthe"Greenand Blue Shales and Limestones;" this, however, ^is not a name, ^but descriptive phrase,and has the disadvantage^ofbeing baseduponlithologicalcharacters noteverywherecharacteristic ofthesebeds.

In viewofallthe_facts,we haveconcludedtopropose the

name

Cincinnati Group (which^willbe adoptedⁱⁿthe forthcomingreports oftheIllinoisGeo- logicalSurvey) ^{forthisseries.} This

name

possesses the advantage^ofbeing equally applicable ^torocks ofany^{color or}composition, while^itcarries the mindtoawell-known_locality,wheretheformationreferred toisextensively developed,and its fossilsso abundant that theyhave beenthence widely distributed,bothin thiscountryand _Europe. Consequently,geologists will everywhere^atonceunderstandtowhatparticularhorizonoftheLowerSilu- rian this

name

refers.

Descriptions^of

New

Crinoidea,&c,from the Carboniferous Rocksof Illinois andsomeofthe adjoining^States.

BY

F. B.

MEEK AND

^A.H.

WORTHEN.

Genus

POTERIOCRINUS,

Miller,1821.

POTERIOCRINUS InDIANKNSIS, M.

& W.

Body^ratherdeeply cup-shaped or truncato obconic. Base basin-shaped, comparatively^ratherbroadly truncated below by^the columnarfacet. Basal pieceswell developed, pentagonal, about one-third wider thanhigh. Sub- radials large, threepentagonal,and twoontheanalsidehexagonal,^therebeing nodefinedangle^atthemiddleof theundersideofanyofthese plates. First radialpiecesabout halfaslarge as the subradials,wider thanlong,rounded on the outside,and _nearlypentagonal, or with one or bothofthesuperior

1865.]

156

PROCEEDINGS OF THE ACADEMY OF

lateralanglesslightlytruncated, so as to give an obscurely hexagonal^orhep- tagonal^outline; all broadly truncated nearlytheir entirebreadtb above,and one on the immediateright of theanal_{series,resting}inpart directlyupon^the upper truncated^{side of}oneof the subradials,and elevated almostits entire length above ^thehorizonofthoseof theotherrays. Inthislatter ray,and theone ontheimmediateleftof theanal_series,thesecond _pieceisquadran- gular, andwider than_long,whilethethird is pentagonal, and_supports the firstdivisionof thearmsonitssuperior sloping^sides. Thesedivisions in the ray onthe right are simple,rounded,and each composed^ofasingleseriesof somewhat wedge-shaped pieces; whiletheleft branchoftheone ontheleft of theanal_series,bifurcatesagain on^thesecond _piece,making^threearmsin thisray, whichare constructed like thosealready described,and continue simple^{as far as}they can betraced. In the only other ray preserved ^{in the} specimen,the bifurcation takes place on^thesecond_radial,beyond which^the armscontinue_simple.

First anal piecenearly^as large asoneof the firstradials,hexagonal,and restingbetweentheupper sloping^sidesoftwoofthe subradials, partlyunder thefirstradialontheright,whileitconnectsontheleftwiththesecond anal, and_{supports a}thirdon its truncated upper ^side. Second analpiece rather large,longer than wide, hexagonal,and_resting upon ^the superior truncated sideofoneof the subradials. Third analpiecesmallerthanthe others,hexa- gonal,and surmounted_byseveralother hexagonalpiecesindirect succession, belonging^tothe.proboscis.

Surface apparently smooth. Columnarfacetrather_largeand markedwith distinctradiating^stria?aroundthemargins.

Length^ofbody^tosummitoffirst radials,about_0-48,excepting^{in the}ray ontheimmediateleftof theanal_series,whereitis0-58inch; breadth about 0-56 inch. Breadthofcolumnar_facet,0-26 inch. Usual diameterof thearms afterthe bifurcations,

012

inch.

Locality and_position.

Crawfordsville, Indiana. Keokuk division of the Subcarboniferousseries.

POTERIOCRINDS (SCAPHIOCRINUS) TENUIDACTYLUS, M.

& W.

Bodyⁱⁿ comparison with^the length^{of the}armssmall, inverselycampanu- latebelowthesummitof thefirstradial pieces;beingnarrowly rounded below and rather expandedabove, where the breadth isnearly twice ^the height.

Baselessthanhalf aswide_{as high,}basin-shaped,^{the sides}rounding under^to thecolumnar _facet, which is of mediumsize and a little concave. Basal pieceswell developed, pentagonal, and wider than _long. Subradial _pieces twiceor threetimesas large as the basal;thoseonthe anterior side (theonly ones seen) hexagonal. First radialswider butshorter thanthe subradials;

transverselytruncated about three-fourths their entirebreadth above,^forthe reception^{of the}succeedingradial pieces;thoseonthe anterior sidecurving a littleoutwardsandhaving anirregularpentagonaloutline, thesuperior^lateral angles being more^or less truncated, ^orrounding inwards. Secondradials pentagonal, nearly^aslong^aswide, separatedbyinterradialpieces ofnearly their

own

breadtb, rounded andconstrictedaroundthemiddle, withthe central superior angle prominent, and^thesloping margins on each^sideofitsupporting thearms.

Analpiecesunknown.

Arms

long, slender,andintwoof the anterior rays

known

^tobifurcateon thetenth pieceabove thethird primaryradials, after which_theyareseentobe extended to aconsiderablelength, without,showing distinctlyanother_division,though ^thereissomeappearance^ofsuchbifurca- tioninoneofthebranches,on thetwentieth _piece. Immediately^afterthe division of therays on the thirdprimaryradials, the armsareroundedand composed^ofwedge-shaped pieces,wider than _long, and alternately thicker and thinner on oppositesides,each one supporting^{at its} largerend astout [Aug.

NATURAL

SCIENCES OF

PHILADELPHIA.

157 tentacle. Above thebifurcation on the tenth piece,the divisionsare_very- long, slender,somewhatangular on^the outerside, and stillcomposed^ofa single series ofwedge-shapedpieces,each oneofwhichisstronglyprotuberant laterally,^forthe receptionof atentacle atits larger end, theprotuberances andthe sinuositiesbetween_{giving the}divisionsof thearmsazigzag appear- ance,somewhatlikethose of Platycrinus nodobrachiatus, Hall.*

Surface apparently smooth,^oronlyfinelygranulose. Suturenot impressed between theplatesofthe body, butsomewhat_gapingbetweenthefirstand secondradials.

Height^ofbodyto topoffirstradials, 0-41inch;breadth,^{0-60 inch.} Length ofarmsto firstbifurcation, 0-70inch;^entirelength nearly^{3 inches.}

This_speciesseems toberelated to several ofthose described by^Prof.Hall from thesame localityand _position,but on comparison^will befound notto agree^{inall its}characters with the description ofany^ofthem. Fromhis S.

spinobrachiatus^itevidently^differsinnothavingthe plates of thebodyconvex, northesutures indented attheir angles, as wellas innot having ^thearms subspinous,andthewhole body^islessbroadly cup-shaped.

FromS. Whitei, Hall,^itdiffersinnot havingthe " surface ofcupmarked by deeply impressed pits" at thejunction of^{the sidesof the} subradials,and betweenthefirstradial pieces:andfromS.Halli,Hall,^itdiffersinnot having the arms _simpleafterthefirstdivisionon the second primaryradial,as well asinsomeofthe details of their divisions.

Locality and_position. Burlington, Iowa. Burlington Limestone ofSnb- carboniferousseries.

POTERIOCEINUS (SCAPHIOCRINUS) BaYENSIS, M.

& W.

Body^of

medium

_size, rather depressed obconicbelowthetop of^{the first} radials. Base about twiceaswide_{as high,expandingdirectly}fromthehead ofthecolumnon alinewiththesubradialandfirstradial pieces. Basal_pieces moderately developed, wider thanlong, pentagonal,and showing ^{the whole} surface ofeach ina side view. Subradials aboutthreetimesaslarge as the basal,somewhatwider thanlong, threehexagonal,and two onthe analside apparently heptagonal,^theangle on^themiddleoftheundersideofallbeing very^{obtuse. Firstradial} pieces widerand alittleshorter thanthesubra- dials, all pentagonal, apparentlytransverselytruncated their entire breadth above. Secondradials of nearlythesamesizeasthefirst,andlikethem_pen- tagonal,but having^themiddle angle above and more_salient,whilethetwo superiorsloping^sideseach supports an arm, thus givingorigin totwo armsto each _{ray, or}ten totheentireseries; allofwhich are nearlyⁱⁿ contactall around below, excepting on^the analside.

Firstanal _piecesmaller thanthe subradials,hexagonalin form,and_resting betweentheupper sloping^sidesoftwoof the subradials,withitsupperright edge supporting one ^sideofone ofthe firstradials,and its left connecting apparently with a second analpiece, theform of which cannot bemadeoutin our specimen. ^{Inthe third} range,onepiece evidently rested upon^theupper truncated edge^ofthefirst anal _piece,butits formandconnection with the otherpiecesonthelefthave not been determined.

Arms

_long,and,asfarascan be determined, apparently simpleafterthefirst divisionofeach ray on^the second radialpiece; eachcomposed^{of a}single seriesofwedge-shapedpieces, alternatelylonger and^shorteronopposite sides, but not protuberant on^eitherside;those nearthelowerpartaboutaslong on thelonger^{sideas theirbreadth.} Tentacles numerous, ratherstout,and com- posed ofjoints three or fourtimesaslong ^aswide,andnot swollenor dilated atthe ends.

Columnofmoderate thickness near_{the base,}where itisroundand com-

*IowaReport, p. 542.

1865.] 11

158

PROCEEDINGS

OP

THE ACADEMY OF

posed^ofalternately thicker and thinner pieces. Surface apparentlysmooth Sutures_slightlyfurrowed excepting those between^thefirstand secondradial pieces,which aredistinctlygapingwhen thearmsare folded together.

Height^ofbodytothe top of the^firstradial pieces, 0-25inch; breadth of^do.

0-48 inch. Length ^ofarmsabovethesecond radials, 1-90inches ormore;

diameter ofcolumnatitsconnection withthe base, 0-13 inch.

This species seems to beclosely related to S.decabrachiatus, Hall,(Iowa Report, p.679,pi.xxv._fig.1,)butis largerand morerobust,anditssecond radial piecesdiffermateriallyⁱⁿform,being nearlyor quitetwiceaswideas long,while in S.decabrachiatus theyare ''nearlyonceand ahalf as long^as wide." Its basal pieces are alsoproportionallyabout twiceas large. Other differenceswoulddoubtlessbe apparent,^ifwehadthemeansofcomparing^all thecorrespondingparts ofeach with those ofthe other.

Localityand_position. BayCity,PopeCo.,Illinois. Chesterdivisionofthe Subcarboniferous limestoneseries.

POTERIOCRINDS (SCAPHIOCRINUS)^?NoRWOODI, M.&

W.

Bodysmall,depressed basin-shaped, rounded andconcave below, breadth three times asgreat^astheheight^tosummit^offirstradial pieces. Basalpieces verysmall,deeplyimpressed within the concavity^{of the}under_side,and almost entirelyhidden by^thecolumn. Subradial_piecescomparatively^welldeveloped, curving under^toconnectwiththeconcave base; threepentagonal,(exclusive of.the scarcely-defined angle^atthemiddle below,)and twoon theanal side hexagonal. ^Firstradialpieces short,and about twiceaswideashigh,pen- tagonal,withtheupperside transverselytruncateditsentirebreadth. Second radials aswide asthe

first,and twice_{as long,}pentagonal,andatthemiddle above acutely angular.

Arms

after thefirst division on the second radial bifurcating at leastonce more, onthe third or fourth piece, thejointsbeyond beingslightlylonger than wide, and supportingalternatelyonopposite sides of thearms _strong, long-jointed,rather remotely-separated ^{tentacles. First} anal _piecenearly^aslarge asoneof the subradials,pentagonal, andresting betweentheupper sloping^{sides of}twoofthe subradials,withitsrightsuperior sloping^sidesupporting^theleftundersideofafirstradial,and its leftupper sidea thirdanal _piece, while its shortleftvertical sideconnects with the second analpiece. Secondanal aboutthe sizeofthe_first,and_resting upon the shortupper truncated^sideofoneof the subradials,withits leftsidecon- necting with oneofthe firstradials, and its rightwith another anal piece.

Abovethese severalotheranal pieces areseentorisesoas toform apparently a narrow, rounded,lateral proboscis,on a range with ^thearms, which ^itap- pearsto scarcelyexceedinthickness. Summit and column unknown.

Surfacenearly or quitesmooth, excepting anangularridge or carina,which extends up each second^radialitsentire length. Suturesdistinctandindented alittleattheconnectionsofthecornersof thefirstradialsandthesubradial pieces;thatbetweenthefirstandsecond analpiecesgaping.

Height^tosummitoffirstradial pieces,

005

inch;breadth,^{0-15 inch.}

Thislittlespecies presents rather a combination^ofcharacters belo"gingto several groups. ^{In the}number andarrangement^ofits anal piecesforming apartofthe walls, as well as in the general^structureofits body,^it agrees withPoteriocrinus,anditsdepressed form and round deeply-concave underside are charactersbelonging^tothe groupZeacrinus,while theformofitsarms, andthe distinctlygaping character^ofthesuturesbetweenits firstandsecond radialpieces, suggest ^{relations to} Scaphiocrinus. ^Its apparentlydistinctly lateral,slender, rounded _proboscis,however, would removeitentirely from thegenus Poteriocrinus to Cyathocrinus. Indeed if

we

could be sure the lattercharacter^is real,and not produced by^{the accidental}foldingtogether intoacylindricalformofmerely apartoftheexternalwallof the largetrunk bo characteristic of the genusPoteriocrinus,

we

would not hesitate to call

[Auj

g-

NATURAL

SCIENCES

OP PHILADELPHIA.

159

itCyathocrinus Norwoodi,^{since the} absenceof the large trunk-like summit, andthepresence^ofaslender lateral proboscis, arecharacters probably^ofmore importance, than^thepresence^{of a}fewmoreanalpiecesandthe differencesin theformof thebody.

Named

inhonorof Prof.J.G.Norwood,of theUniversity of^Missouri.

LocaUty andposition. HancockCo.,Illinois. St.Louisdivision of theSub- carboniferousseries.

POTERIOCRINDS (ScAPHIOCRINDS) SUBTUMIDUS, M.&

W.

Bodybasin-shaped below^thesummitof thefirstradial pieces, threetimesas wide_{as high,}composed^ofthicktumidplates. Basal_platesverysmall,deeply impressed,and hidden by^the column. Subradials comparativelylarge,very convex,and extending out nearlyhorizontally,but curvingupward ^attheir outerextremities;aboutaslongas wide, threeofthemsubhexagonal, and two subheptagonal,^theangle^atthebasal or inner sidebeing nearly^obsolete. First radialsconvex, about twiceaslarge asthe subradials, half as highas wide, regularlypentagonal,andallnearlyevenly truncated above,^theiremirebreadth.

Anal _plateslikethe others,tumid;^firstone onehalftoone-third as large as the subradials, irregularlypentagonal,and _{resting obliquely}beneath oneside ofafirstradial,betweentheupper sloping^{sides of}two subradials,while its left and _upper sideconnect withtheotheranals. Secondanalpiece .resting upon^thetruncated upper^{side ot}oneofthe subradials,andconnecting on^the leftwith a firstradial,abovewhich itprojects nearly half^itslength. Third anal piecehexagonal,supported upona shoittruncated upperside of thefirst anal,andconnecting on^theleftwiththe second,andon the rightwithafirst radial,abovewhichitprojects a^little.

Secondradialsand_partsaboveunknown. Surfacesmooth;suturesstrongly defined,ⁱⁿconsequenceof thetumid character ofthebodyplates.

Height^ofbody^to summitoffirst radialpieces, 0-27 iuch; breadthof do.

O-TSinch; breadthof base, 0-13 inch.

Untilspecimensof this speciescanbeexamined, showingthe struc'ure of the partsyetunknown,^{itwillbedifficult to determinewhetherits} name should notbe moreproperly Zeacrinus subtumidus, orwhether it

may

^notbelongto another group, ofwhichGraphiocrinusli-brachialis,of Lyon,^isthetype*

Thislatterformdifferswidely,not only fromPoteriocrinusproper,but from Scaphiocrinus,Zeacrinus,andalsofromGraphiocrinus,ⁱⁿhaving ^itsarmscom- posed each^{of a}doubleseriesofinterlocking pieces, as well as in^itsunusually massivetumid_platesand _generalphysiognomy. ^Insomefamilies of the Cri- noidea,suchforinstanceasthe Platycrinusgroup, adifference like thisinthe structure of thearms

may

^{be ofless}importance, but^inthatincluding^Poterio- crinus and the allied genera,webelieve ittobeofmoresignificance,^ifnot indeedofgenericvalue, especiallywhen accompaniedby^theotherdifferences of habitpresentedⁱⁿ thisinstance. Hence wewould_proposefur thisgroup thenameEupachycrinus, with Eupachycrinus^{14-brachialis}

=

{Graphiocrinus^14- brachialis,Lyon)^{as the}type. ^Itwill alsodoubtless include E. pentalobus

=

(Cyathocrinus?pentalobus, Hall,)andpossibly also Scaphiocrinusorbicularis,Hall.

Should ourspecies here under consideration prove^to have itsarmscon- structedof adoubleseriesof pieces,weshould unhesitatingly^callitEupachy- crinus subtumidus, since in themassive tumid characterofitsbodypieces,small sunken_base,andgeneral form and appearance,^itagrees, so far asitsparts are known,essentiallywiththetype^ofthat group. Specifically,however,^itwill bereadilydistinguished by^its subradialpieces being proportionally smaller and somuch less protuberant ^{as to}give a different outline to theunderside of the body,^as seen inasideview. It alsodiffersentirely in theform and arrangement^ofitsanalpieces.

Localityand_position. BayCity,PopeCo.,^Illinois. Chesterdivisionofthe Subcarboniferousseries.

* SeeKentuckyGeological Eeport,^vol.iii.p.477,pi.^i.figs.2and2a.

1865.]

1<30

PROCEEDINGS OF THE ACADEMY

OF Genus

CYATHOCRINUS,

Miller,1821.

Cyathocrintjs arboreus, M.&

W.

Body^{rather under}

medium

size, conoidal-semiovate belowthetopofthe firstradial pieces,aboutaswide_{as high.} Basal pieces welldeveloped, form- ing a low basin-shaped cup;^all pentagonal,andaboutas long^aswide, the greater breadth being slightlyabovethemiddle. Subradial pieces three or four times as large as the basal,aboutas long^aswide, usuallyarcuate, or alittleconcave onthe outsidealong the lateralmargins ^fourhexagonaland one heptagonal. ^Firstradialpieces ofnearthesame sizeas the subradials, ar.d presenting ^amoreorlessnearlypentagonal^outline;facet for the recep- tionofthesecond radials nearly equalling one-third ^thebreadthofthefirst radial pieces, slightlyprotuberant,andslopingoutwards. Succeeding^radials small,rounded on theoutside,and varying from two tofive in the different rays; there being^buttwoinoneof theposteriorraysand fiveinthe other, whiletheanteriorray hasfour,one ofthe antero-lateralthree,and theother four, ^allexcepting^thelastor axillary piecebeing quadrangular.

Afterthefirstdivision intotwo armsonthe fourthprimaryradial piece, (at leastin oneofthe antero-lateral rays,)another division immediately takes pla "e on thefirstpiece ofeach _principalbranch, and^{of the}four branchlets thus foumed,^theinnertwoascend_directlyupwards,andeachbifurcatesagain onthesecond_piece,andthesubdivisionseach again onthe third piece;while thetwo mainlateralbranchlets spread out oneither side,each giving^offabove twoormore subordinate branchlets, the^firstofwhichis seentobifurcate at least once. Thewholeof the divisionsand subdivisions being thus spread out to as toresemblethe trainedlimbsof a treespreadupon^awall. Thedivisions of theother rays cannot be^tracedoutinthespecimen examined,^inthesame

detail,butsomee>fthem_appeartodivide much in thesameway,andothers somewhatdifferently.

Allthearmsandtheir divisions aierounded,andthesmallerdivisionscom- posedof joints that arelonger thanwide,while notentacleshave been observed connected withany^ofthem.

Thefirst analpiece ^is quadrangular, a ^littlelonger than one of^thebasal pieces,and rests directlyupon thesuperiortruncated sideofone ofthesub- radials,whileitconnects on eachsidewithoneofthe large^firstradial pieces, above whichitdoes notproject. Otheranal piecesunknown.

Thesutures^are slightlyimpressed,andthe surface nearly smooth,^oronly obscurely granulose. The column and summitareunknown.

Height^tosummitoffirstjadial pieces, 0-66 inch,ontheanal_side,and0*55 inch onthe other; breadth _{at top of}firstradial pieces, 0-53inch; breadth of secondandsucceeding primaryradial pieces,

015

inch.

Locality and_position. Crawfordstille, Indiana. Keokukdivision of Sub- carboniferousseries.

Genus

PLATYCRINUS,

Miller, 1821.

As^firstproposed byMiller, thisgenus was_{badlydefined,}anditismanifest thatitsauthor _himself,had no very^{clearideas of}its limits,sincehealsoin- cludedinitspecies of Pentremites, Say,Dichocrmus, Munster,and of his

own

genusActinocrinus. Later_writers,however, have^restricteditwithinfarmore natural_limits,and,^as

now

_generallyunderstood,^{Miller'sfirst}species,P._Icevis, seemstobe regardedas the typicalformof thegenus. ^Inthisandthe closely allied species, thebody^ismore^{or less} hemisphericalbelow thearms, while thedome terminates aboveinalong, generallyslender, central or subcentral proboscis, closedat thesummit, but apparently pierced by^asmall aperture on onesideneartheupperextremity. In thesetypicalformsthearms bifurcate onceor oftenernearthebody,beyond which they^are simple,and composed atfirst,of a single series ofwedge-shapepieces,passingmoreorlessgradually

fAug.

NATURAL

SCIENCES OF

PHILADELPHIA

161 intoadoubleseriesofsmall interlockingpieces supporting numeroustenta- cles. Other_species,however,generallyincludedin the genus, have no pro- boscis,but a simple aperture^{in the}summit,located either laterally, ornearly centrally; whilesomeofthesehavethe arms composed^{ofadouble seriesof} interlocking pieces,and othersofa single series of wedge-shaped pieces,*

neither of these peculiaritiesⁱⁿthestructure of thearmsbeing alwaysespecial- lycoincidentwith apparentlyany^{oneoftheothercharactersmentioned.}

As definedby Koninck and Le Honf,in accordance with their improved nomenclatureofthe parts, the structuralformulaof thisgroup^isasfollows:

Basal_{pieces, 3}; forming^awide_cup.

Radials,2; onelargeaudonesmall.

X

^5.J Anals,¹large,or3 small.

Interradials,1,

X

^4.

Arms,10,20, 25,30or 35,according^tothe species.

Fromtheforegoing remarks,^itwillbeseen, that thegroup includingspecies agreeing with ^the above formula,

may

^bedivided, as (in part)suggested by theMessrs.Austin,$intothefollowingfour sections:

1. Platgcrinus, (typical). With the summit terminating ⁱⁿamore orless elongated, central, orsubcentral proboscis,bearing ^the opening on oneside neartheupperextremity.

Type. P.Ixvis,Miller. Also includes P._spinosus,andP.30-dactylug,Austin;

P.Miillerianus,Koninck; and P.granulatus,^Miller.

2. Centrocrinus,Austin. Opening ^ofsummit _nearly or quite central,but notelevatedupona proboscis.

Type. ^P.\_Centroer.~\gigas, Gilbertson.

3. Cupellseocrinus, Troost. Differs from the last onlyⁱⁿ having^itssecond radial piecesmerely rudimentary,^{or so}smallas toallowthefirstbrachialsto rest partlyupon^thefirstradials.

Type. P.Tennesseensis,Roemer.

4. Pleurocrinus,Austin. DiifersfromCentrocrinusonlyⁱⁿhaving^the open- ing^{of the}summit_lateral,and_{nearlyor quits}on alinewith thearmbases

Examples. ^P.[Pleurocr.~\ mucronatus, Austin;' P.\_Pleurocr.] tuberculatus, Miller; P. [Pleurocr.~\ tuberos us,and P.[Pleurocr.~\ subspi?iosus,H>i\l; P. [Plev- rocrA_asper,

Meek

&Worthen,&c,^&c.

Inregard^tothevalue and importance^ofthecharacters distinguishing^these sections, Palaeontologists will probably always ^differ. Hitherto these differ- enceshave _scarcelybeen _noticed,even by^the most respectable authorities, excepting^asoneof themeans ofdistinguishing species. From all analogy, however,^itseems reasonabletosupposethat theywere accompanied by ^cor- respondingmodificationsinthestructure of the softer parts of theanimal. It will alsobe observed,^thatthey correspond,ⁱⁿpart,almostexactly to thecharac- tersdistinguishingsections ofthe allied Aclinocrinusgroup. For instancethe speciesembracedin thesection Pleurocrinus,differfrom the typical forms of Platgcrinus,almostprecisely asAgaricocrinus andAmphoracrinus do from the

*P. nodobrachialus, Hall,^isan American example withthearms composed^ofasingleseriesof pieces. Wealludehere toaspecies describedunderthatnamebyProf. Hall, in theIowaReport, p.542, 1S58,aud nottoanotherformdescribedby him under^thesame name,inhis"Descriptions ofNewSpecies of Crinoidea, Ac."Albany, Feb.25,1851,p.17. The inconvenience andconfusion liable toresultfromthe use of thesame_specificnamefortwo formsofthesame genus, makes itnecessary thatanothernameshouldbe applied^tooneof these species;hencewe wouldpropose to callthat described at thelatterdate,P._perasper.

fRecherches SurlesCriuoidesduTerrain Carbonifere deLeBelgique,p.155, 1854.

Jit^isworthy^tfnotethatalthough Koninck and LeHon_givetworadials (one largeand one small) as thenumber,thattheir figure¹a, pi. vi.of P. Ixvis, Miller,shows_clearly 3radials, onelargeand twosmall. Asothers figureanddescribeitashavingonly two. thismay^beonly anaccidental variety. It willbe seen,however,thatourP. parvulus, describedon another page of this paper, has 3 radials,onelargeand twosmall. Stilltwo seemstobe thenormalnumber in this genus.

JMonograph^{ofRecent and}Fossil Crinoidea,p. 6.

1865.]

162

PROCEEDINGS OF THE ACADEMY

OP

typicalspecies of Actinocrinus. Hence,^ifweadmitthese lattergroups,^either asgenera^orsubgenera, consistency^atleast, ifnotindeeda philosophicalsystem ofclassification,wouldrequire thatequalprominence should be given^tothese correspondingsections of the Platycrinus group. Whatevertheoreticalviews

may

^beentertainedonthis subject,however,^the practicaldifficultyofascer- taining thenatureofthesummit,andthe position of theapertureⁱⁿpalaeozoic crinoids, willprevent^thegeneraldistribution of the species into groups,upon charactersof this kind, unless amore profound study of great collectionsof theremains ofthese animals,mayyet bring ^to light some coincident, but more _easilyobservedcharacters, in the structure of thebody,^orotherparts.

PlatycrinusNiotensis, M.and

W.

Body^belowthe summitof thefirst radial pieces cup-sbaped, wider than high; sidesslightly ventricose abovethe base. Base basin-shaped,^several timesaswide_{as high,}moderately expanding,^rather broadly truncated below, itslower marginsprojecting slightlydownwardsaroundtheendof thecolumn, and provided with^threevery smallprojections,oneatthelowerextremity of each ofi's sutures. First radial plates large,higher than wide, widening slightlyfrom below upwards, subquadrangular or with the superior^lateral angles^a-\ittle truncated by^the interradial pieces; eachwithaconcave facet for the reception of thesecond_radials,equalling about^halfitsbreadth above, andexcavated near one-fourthitslength on ^the outer_side,below _{the upper} margin. Secondradial pieces trigonal,verysmall, orscarcelyfillingthe facet orexcavationintheupper^{sideof thefirstradials}; rounded below, with each superior sloping^sidesupporting secondaryradials,on the second ofwhich anotherbifurcation takes place,making^fourarmstoeachray.

Arms

aftertheseconddivisiondescribed above,simple,andatfirstcomposed each of^asingle seriesofwedge-shapedplates,but soon passing^{into a}double series ofsmallinterlocking pieces,supporting on each^sideofthearms_closely arranged^seriesoflong-jointed tentacles.

Columnnearthebase compressed and _{tortuous,being} composed of alter- nately thickerand thinner _{elliptic pieces,}with a very minute ^centralper- foration.

Surfacesomewhatgranulose^{; sutures}not grooved, nordistinctlyapparent;

those between^thebasalpieces indicatedbya faint linear ridge.

Height ^to summit of first radials, 0-30 inch; breadth about 0-40inch.

Grea'er diameterof column at base of body, 012inch

; smaller do.0-09.

Breadthof one of thearms,006_{inch; length}of do.apparently an inch or more.

Initsgeneral appearance,^{this speciesis}not unlikeP. sarceof_Hall,(Iowa Report,p. 673,pi.18,fig.4),though^{it is}muchsmaller,hasa proportionally muchshorter base,andalsodiffersinhaving butfour, insteadofsix armsto eachray.

Localityand_{position. Niota,} Hancock County, ^Illinois. Keokuk division ofSubcarboniferous Limestone.

Platycrinus hemisph^ricus,M.and

W.

Bodyrather abovemedium size,hemispherical, being rounded _below,and about twiceas wideas high^; base broad basin-shaped,and _forming about onethird the entireheightof the cup,withapentagonal ^{outline as} seenfrom below; columnarfacetbetweenone-third,andone-fourththe diameterof the base,andsubellipticalⁱⁿoutline. First radial pieces largerthan the basal, wider thanhigh, nearly quadrangular, and widening moderately from below upwards;facet for the reception of thesecondradialonethird as wideasthe summit, and extendingdownabout onefourth thelength ofthe plates, con- cave and _slopingoutwards, with^adeep notch^within. Second radial pieces verysmall,butfillingthe cavityⁱⁿeachofthefirst radials,from which_they

[Aug.

NATURAL

SCIENCES OP

PHILADELPHIA.

163 extend out nearlyhorizontally pentagonalⁱⁿoutline,andeach supporting on itssuperior lateralslopingmargins^{the first} divisions of the arms,which are comparatively small and^bifurcateagain on^thesecondpiece; beyond^thisthe twoouter divisionsremain_simple,butthetwoinnerdivideagain on^thesecond piece,making^sixarmstoeachray, or thirty to the entire ^series.

Arms

after the last divisions long, slender, cylindrical,and composed^{at first} ofasimple seriesofquadrangularpieces,but passing graduallyupwards^intointerlocking triangular pieces,andstillfartherup forming a double^seriesofsmallalterna- ting cuneiform pieces,supporting closely arranged, long-jointed tentacles.

Anal,interradial,and vault piecesunknown. Sutures,excepting between^the basal pieces, distinctly,but not widely^ordeeply channeled.

Surfaceornamented withrather small,but well denned, prominent nodes.

On

the base, tnese nodes are arranged ^{in ten} rows, ^five ofwhich radiate fromthecolumnarfacet,onetoeachofthecorners; while thosebetween each of theseform intermediateradiatingrows,consisting at^firstofa_singlerange, butbecoming^adoubleortriplerange near^the margin,when the threesome- timescoalesce laterally.

On

thefirstradial pieces two rows pass fromjust beneaththe facet for the reception of thesecondradials, toeachof the inferior lateral angles,whilebetweenthese there_is,atfirst,a singlenode, but^farther down two orthree rows,consisting of nodes which showa disposition to elongate, or coalesce laterally, so as toformlittle transverse _ridges. Above, thereisalsoarow_extending horizontally^toeach superior lateral angle,with afewlessregularlyarranged nodes on^{the sides} belowthese.

A

single trans- verselyelongated node sometimes also occurs on thelittleradials,and one lessdistinctly defined alsosometimes on eachofthe piecesbetweenthisand thenextbifurcation.

Breadthofbody^atsummitoffirstradial pieces, 1-07inches; height ^{of do.}

0-60 inch

;breadthofbase067inch; breadthofsecondradial pieces at the summit,^0-54inch; do.of secondradials, 0-19 inch.

From

the description,^itwill be seenthis species is rather closely related to P. granulatusofIMiller,whichitnearlyresemblesin form and_generalap- pearance. ^Itisa largerand more robust_species,however,and _differs,not only^inthearrangement^{of the} pustules on thebase into distinct radiating rows, but according^toAustin'sfigures anddescription (Monogr., Recentand

fossilCrinoidea,p.33,pi. 3,^f.2,)inhaving but^{six instead of}sevenarmsto each_{ray, as}wellasinhaving^thearmsabovethemiddlecomposedof adouble seriesofsmallwedge-shaped pieces, instead ofconsisting of a single series throughout. Fromitsanalogy^toP.granulatus, of Miller,itwillprobably be foundtopossess, like that species,a long subcentralproboscis.

Localityand _position. Crawfordsville, Indiana. Keokuk division ofSub- carboniferousSeries.

Platycrinusparvulus, M. and

W.

Bodyverysmall,shortsubcylindrical, ordeeply cup-shaped. Base depressed basin-shaped,^{or several}timesaswide_{as high,}columnarfacetabout onethird aswideasthe base,withasmall marginal^rim. First radial platesnearly ob- long,being longer than ^wide,with nearlyparallel sides

; someof themwith

two obscurelinear ridgesextending from the middleofthe upper side,and slightlydiverging^tothebase; each moderately concave abovefor the recep- tionof thenext range of pieces. Second radial pieces very minute, about twice aswideas long,but not equalling^thebreadth ofthe slightconcavityⁱⁿ theupperside of thefirstradials. Thirdradial pieces, slightlywider thanthe second, and about of^thesamelength,pentagonal,andeachsupporting anarm on eachsuperior sloping^side.

Arms

each dividingon the second_{piece be-} yond whichtheyare simple, at least for four or five pieces above,and com- posedof a single series ofquadrangular pieces,aboutas long^as wide, ex- cepting^thefirst,whichisnear twice aslong^{as wide.} Tentaclesapparently 1865.]

164 PROCEEDINGS OP THE ACADEMY OP

comparatively^stout. Columnnearthebase nearlyor quite round,and com- posed^ofverythin pieces. Surface smooth.

Length^ofbody^tosummitoffirst radial pieces 0-12inch; breadthof do.

0-12 inch. Length^ofarmabout0-30inch; ^thicknessof column,^0-02inch.

This very smallspecies,^differsremarkably from ^{all the others} with which weareacquainted, resembling ^itin otherrespects, notonly^inits small size, butinhavingtwominuteradial piecesineachray,above_{the larger}firstradial piece,makingthree radials toeach_ray.

Localityand_position. PopeCounty,^Illinois. Chesterdivision ofSubcarbo- niferous Series.

Genus

ACTINOCRINUS,

Miller,1821.

Subgenus

ALLOPROSALLOCRINUS,

Lyon &Casseday,^1860.

Actinocrinos (Alloprosallocrinus) euconds, M.&

W.

Bodyhaving^the form ofthe subgenus remarkably^welldeveloped, being perfectly^flator slightlyconcave belowthearm bases,andregularly conical above,whereitterminates inarather slender central proboscis. Base very small,witharound,deep, conicaldepression^forthereception^ofthecolumn, occupying almost^itsentirearea, andsurrounded by a narrow, slightlypro- jecting ring-likemargin. Radial, interradial, analand first brachialpieces, allextending out horizontallyfrom thebase. First radialpieceshexagonal andabout twice as wideas long. Second radialstransversely oblong, and rather,smaller than thefirst. Third radials alittle larger thanthe second, pentagonal^orhexagonalⁱⁿform,andeach supporting on^itssuperior(more properly outer) sloping ^sidestwo _{slightlylargersecondary radials,} each of which ^{is succeeded} byanother, and thelattereach bytwobrachial _pieces, making^four arms toeachoftwo _raysseen, ortwentyto the entire_series,if the othershavethesame number. Firstinterradialpieces largerthananyof the radials,heptagonal^oroctagonal, andsupportingtwosmallerpiecesinthe nextrange,beyond which^aretwo_others,making altogether^fivepiecesⁱⁿthe onlyinterradialarea

we

have beenable tomakeout_clearly. Anal _piecesun- known.

Vault regularly conical,with_slightlyeonvex _slopes,and armed aroundthe middle withtwo orthreerowsof irregularly disposed, short, conical spines, or spine-like tubercles. Proboscis slender and _apparently not inclined to either side.

Surface smooth,or indistinctlygranulose; sutures very ^close fittingand

difficult tosee.

Arm

basesforming an almost continuous ^series(being but veryslightlyinterrupted ^atthe analandinterradialspaces)aroundthebase of theabruptly truncated^conicalbody. Column unknown.

Height^tobaseof proboscis,about0.70inch; breadth,1.13 inches.

This_speciesisremarkableforitsconical form,being almostperfectlyflat,or alittleconcave belowthehorizonof thearmbases,and_risingwith _slightly convex slopes above,^{to the} baseof theproboscis. Hencethewholeofthe cavityoccupied bythe viscera of theanimal corresponds ^tothedome_{only of} species oftheusualformof Actinocrinus. Forthe group ^towhichitbelongs.

Messrs.Lyon & Casseday proposed ^the

name

Alloprosallocrinus in 1860,and Dr.Troosthad_proposedforitthenameConocrinus, in a^listpublished without adescriptionⁱⁿ1850.

Since^theabovewasintype,amorecarefulcomparison withLyon &^Casse- day's descriptionof theirA.conicus leads ustosuspect ^that ourcrinoidmay beidenticalwiththeirspecies. ^Stillwedonotfeel satisfied thatthisisthe case, particularlyasthey describe ^thecolumnarfacet asinvolving the^basal and _partof thesurrounding range ofpieces; while itisvery small ⁱⁿ our crinoid,not even covering ^the small basal _pieces. Inaddition_{to this,}our specimensseemtoshowthebases ofamore numerousseriesofarms.

[Aug.

NATURAL

SCIENCES OF

PHILADELPHIA. 165

Localityand_position. Sixmilessoutheast of Anna, UnionCo.,Illinois;from theSt.Louisdivisionofth*eSubcarboniferousseries. Collectedby^Mr.Henry Engelmann.

PENTREMITES (GRANATOCRINUS?) granulosus, M.

& W.

Bodysmall, subglobosus, base deeply concave,particularly in themiddle, andnotvisibleina sideview. Radial plates a^little longer than wide, about two-thirds aslong ^{as theentire} body,andtapering from above^tothe base, each divided by^thenarrowpseudo-ambulacralareas,downalmosttothevery base; lateral margins moderately promiuent. Interradialpieces subtrigonal, orwith afourth obscure angle ^{in the} middle below; longer than wide,and each narrowing frombelowtothesummit,where _theyareperforated by two minute openings. Anal _pieceofthesame sizeand form as the interradial, withitsopeningcircular,andcomparativelylarge,^itsouter margin being pro- tectedby^asmall,rather pointed node. Pseudo-ambulacral areas narrow,^or sublinear, rather impressed, and each with a distinctlongitudinal, linear, mesial furrow; pore pieces from twenty-five^to thirty. Surfacemarked by comparatively^distinctgranules,most strongly defined ontheinterradialand anal _pieces,wherethey sometimes show_{a tendency}toarrange themselvesⁱⁿ transverselines parallel to thelower margin.

Height ^ofbody, ^0-22 inch; breadthof do. 0-23 inch. Breadthofpseudo- ambulacralareas, 0-05 inch.

Not_havingathandaspecimen orfigure of thetypeof Troost's Granatocrinus, we arenot_quite sure thisform belongs tothat group,thoughwe haveno doubt in regard ^{to the} propriety^ofseparating suchspeciesfromthe typical formsof Pentremites. Ourspecieshassomewhatthegeneral formand_appear- anceofP.RoemeriofShumard,(MissouriReport,pi.b, figs. 2a,2b, 2cand_2d,), butdifferstoowidely^torender adetailedcomparison necessary.

Localityand_position. Keokukdivision ofSubcarboniferous_series,nearWar- saw.Illinois.

POLYZOA.

Genus

EVACTINOPORA,

^M.&

W.

EVACTINOPORARADIATA, M.

& W.

Theinteresting fossilupon which we propose ^to foundthis genus and species ^isentirelysilicified,and,^as seenfrom below, presents ^theformofa regular eight-rayedstar,theraysbeingslender,and nearly equallinginlength thediameterofthenucleus. In a _{side view,}however,^itis seentobe regu- larlyroundedinoutlinebelow, while^theslender rays areobserved tobe pro- ducedupwards ^{in theform of thin vertical}laminae,whichconverge ^tothe centreoverthe nucleus. The_specimenis notinaconditiontoshowwhether ornotthereisacentral axisextending ^allthe

way

up,but there probably^is.

Therays are thickestbelow,andtapergraduallyupwardsontheirouter margins, which are beveled orcarinated alltheway down^towhere_{they meet}atthe middleofthe underside. Within, they eachpassabruptly^intoathinlamina, whichisporiferouson both_sides,andextendstothemiddle overthe nucleus.

The_poresare circular,with a_slightlyprominent margin,and regularly dis- posed nearlyⁱⁿquincunx,^atintervals about equalling ^their

own

_diameter,or sometimesless. Theyonly^{exist in the thin} portionofeach ray, while the thicker outerandinferior portionsseemtobenearly or quite^solid.

We

are not able to determinesatisfactorilywhetherthiswasa free oran attached Bryozoon; but^ifattached, thestemor point ofattachmentwaspro- bably very^small.

Greatesttransversediametertotheextremityof the rays, 0-90inch; do. of nucleusbetweenthe rays, 0-35inch;thicknessoftheouter margin^ofeach ray nearthe nucleus, 0-10inch;diameterofpores about^{0-02 inch.}

1865.]

166

PROCEEDINGS

OF

THE ACADEMY

OF

Localityand_position. The_onlyspecimen of^thisfossilwehave seenis in a granularmassofdecomposingchert,containingsomefragments^ofsmallcri- noid columns. Itwasobtained fromtheSubcarboniferous rocksof Missouri, buttheexactlocalityandpositionwehave been unableto ascertain.

Note onthegenus

GILBERTSOCRINUS,

Phillips.

BY

F. B.

MEEK.

Genus

GILBERTSOCRINUS,

Phillips, 1836.

Gilbertsocrinus, Phillips,Geol. Yorkshire, partii.,p.207, 1836.

Goniasteroidocrinus,Lyon andCasseday,Am.Jour. Sci. xxviii._p.233, 1859.

Trematocrinus, Hall,Sup.Iowa_Report,p.10,1860.

Phillips'diagnosis^ofthisgenus reads^asfollows:

"

Basaljointsfive,forming^apentagon; suprabasal [subradials]five,hexa- gonal,forming^adecagon with ^fivere-entering angles, fromwhich _proceed

fiveheptagonal ^firstcostals [firstradials] and fivehexagonal secondcostals, [secondradials],bearing^apentagonal scapula[third radial]supportingjoints [secondaryradials]which combineintoroundedarms_perforatedinthe centre.

First in.tercostals _[firstinterradials] pentagonal. The_followingspecieshave been usuallyreferred toRhodocrinus,Miller,from which,^itappears^tome, they differentirely."(Phillips.)

He

mentions but thefollowingthree species,viz.,G.calcaratus,G. mammil- larisandG.bursa,^allfromthesubcarboniferous. Hisspecific descriptionsare very^briefand unsatisfactory,but his figures are tolerablygood,and give a

,sufficiently intelligibleidea of the generic characters^ofthegroup.

From

these .figures,andhis description,^{it is}thereforeevident thattheformula,ⁱⁿaccord-

ance withthe laterimproved nomenclature,

may

^bestated as follows:

Genericformulaof Gilbertsocrinus.

Basal_pieces5.

Subradials5.

Radials3x5.

Secondary^orsupraradials^{3 or}4x10.

Anal andinterradial pieces 12 to15x5.

Pseudo-brachial appendages (arms^ofsome_authors)5,locatedoverthe rays.

Arm-openings(ambulacral,)10,located directlyunder the pseudo-brachial appendages.

On

_comparing thisformula withthe following,given by^Messrs.Lyon and Casseday, ofGoniasteroidocrinus, citedabove,the close relationsofthese crinoids will_be,apparent.

Genericformula ofGoniasteroidocrinus.

Basalpieces1x5,pentagonal,perforationnotvisible.

Subradial_pieces5,hexagonal,nearlyequal^insize.

Primaryradial pieces3x5,^firstspiniferous.

Secondary^radials

3X

10,hexagonal.

Interradialfields[including^theanalarea]

5x13

^to14,[pieceseach].

Interbrachialfields

5x1

^to9,[pieceseach].

It

may

^be proper^to explain ^thatthe term pseudo-brachial appendages isusedintheformula ofGilbertsocrinus, for the partsregarded byPhillipsand by^Messrs.Lyon and Casseday^as arms,and thatarm-openings, not alluded tobyPhillipsinhis description,thoughclearlyshowninhisfigur.s,aremen- tioned. These openings were not observed by Lyon andCasseday, because theywerehiddenin theirspecimensby^theattachmentof thesmall pendulous true arms,or,in the absence ofthe latter,by portions ofthematrix,^asis

known

tothewriterfromtheexaminationofspecimensof their typical species loanedbyMr. Lyon.

/ [Aug.