SMITHSONIAN MISCELLANEOUS COLLECTIONSVOLUME 93, NUMBER 8
THE CLASSIFICATION OF THEEDRIOASTEROIDEA(With One Plate)
BYR. S. BASSLERHead Curator, Department of Geology,U. S. National Museum
VoRBi
(Publication 3301)
CITY OF WASHINGTONPUBLISHED BY THE SMITHSONIAN INSTITUTIONAPRIL 4, 1935
BALTIMORE, MD., D. B. A.
THE CLASSIFICATION OF THE EDRIOASTEROIDEABy R. S. BASSLERHead Curator, Department of Geology, U. S. National Museum(With One Plate)The Edrioasteroidea, a group of Paleozoic echinoderms, regardedby specialists either as a distinct class of the Pelmatozoa allied to thecystids or as an aberrant order of the same division, has been thesubject of so many detailed observations and changes in nomenclaturethat much confusion exists in its classification. Many of the generahave inexact limits assigned them, because they are based upon incor-rect illustrations or described from species other than the cited geno-type, or, again, because they are founded upon characters of uncertainvalue. Lastly, some authors, without regard to the rules of nomen-clature, changed the generic endings to suit their ideas as to therelationships of the group, Agelacrmites, for example, becoming firstAgelacrinus and later Agelacystis. Furthermore, it must be remem-bered that the camera-lucida drawings of years ago resulted in reversedimages, the right side becoming the left, which in the edrioasteroidsgave rise to a serious error since the direction of the ambulacra, ageneric character now believed to be important, thus was reversed.However, most students paid little attention to the extent and directionof curvature of the ambulacra, including in the same genus formsmost diverse in these respects.In preparing the present classification the writer first of all proved,at least to himself, from a study of several hundred specimens ofseveral Cincinnatian species, that the amount of imbrication of theinterambulacral plates, the width of the peripheral border of plates,and the number of arms or ambulacra may vary even in the samespecies ; but the plate structure of the ambulacral and oral areas, andthe direction and extent of curvature of the ambulacra, remainedconstant, thus afifording good generic characters.In their simplest form the edrioasteroids have a flexible theca orsacklike body composed of numerous more or less polygonal plateshaving a mouth on the upper surface at the central point of radiationof five straight or curved arms or ambulacra separated by interam-bulacral plates, and an anus with valvular covering occupying partSmithsonian Miscellaneous Collections, Vol. 93, No. 8
2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93
of an interray with a hydroporc located between it and the mouth.These primitive echinoderms, free or attached by a part of the lowersurface, developed into parasitic circular flattened forms, into elevatedsacklike bodies or into cylindrical objects bearing the ambulacra atthe top of a fused mass of plates. Starting at the left of the analarea and proceeding clockwise, the ambulacra are designated as follows
:
I, left posterior ; 2, left ; 3, anterior (opposite the anal area) ; 4, right
;
5, right posterior. These numbers are employed in the followingdescriptions.Through the study of the Springer and Ulrich collections of Edrio-asteroidea in the National Museum, and of material lent by other insti-tutions, the writer has been enabled to review the structure of most ofthe known genera and species of this group, the generic results ofwhich are offered below. Here, the old genera are briefly redefined andsix new generic names are proposed. This paper is introductory toa more complete publication that will include descriptions of additionalnew species upon which this classification is based.Class EDRIOASTEROIDEA Billings, 1854-^8(Thyroidea Chapman, i860; Agelacrinoidea S. A. Miller, 1877-1883; Cys-tasteroidea Steinman, 1888; Thecoidea Jaekel, 1895; Cystostellaroidea Steinman,1904.) Family AGELAGRINITIDAE, new name(Agelacrinidae Jaekel, 1899; Thecocystidae Jaekel, 1899)Theca flexible, composed of thin plates attached temporarily orpermanently by the greater part of the aboral surface and with am-bulacra confined to the oral surface. A single row of ambulacralflooring plates overlapping proximally.STROMATOCYSTITES Pompeckj, 1896(Stroiiiafocystis Bather, 1900)Theca depressed, pentagonally globular in form with oral surfacebearing five narrow, straight ambulacra separated by polygonal mosaicinterambulacral plates with numerous intervening pores and the undersurface completely occupied by smaller, less regular polygonal plates.Anal area slightly elevated, indistinct.Genotype.—6^. pentangitlaris Pompeckj, 1896. Middle Cambrian ofBohemia. 5. halticus Jaekel, 1899, 6^. zvalcotti and var. minor Schuch-ert, 1919 are other species of the genus.
NO. 8 EDRIOASTEROIDEA BASSLER 3WALCOTTIDISCUS, n. gen.Pentagonal form and general shape of theca as in Stromatocystites,but the oral face bears curved ambulacra, four (1-4) directed to theleft and one (5) to the right. Furthermore, the edge of the oral sur-face is composed of a narrow band of very small nodose plates andthe under side of larger polygonal plates imbricating. Anal areaindistinct.Genotype.—W. typicalis, new species. Middle Cambrian of BritishColumbia. WALCOTTIDISCUS TYPICALIS, n. sp.Plate I, fig. IType specimen, free, depressed, globular, subpentagonal in outline,imbedded and somewhat distorted in hard shale. Oral face with fiveslightly curved ambulacra, four directed to the left and one, the rightposterior, to the right, separated by polygonal interambulacral platesvery slightly overlapping. Edge of oral side formed by a band con-sisting of five or more rows of very small elongate imbricating plates
;
basal side of theca as shown where pushed over oral face, occupiedby large elongate polygonal, imbricated plates. Anal area not dis-tinguishable with certainty.Occurrence.—Burgess shale of Middle Cambrian, Burgess Passnear Field, B. C. (loc. 35 k).Holotype.—U.S.N.M. no. 90754.CYSTASTER Hall, 1871{Thecocystis Jaekel, 1899)Theca an elongate sack with the lower end attached to some foreignobject. Ambulacra short and straight, five in number, with platesoften rather nodose. Interambulacrals rounded or polygonal, mosaic,very minute (0.25 mm in diameter). Anal pyramid of 10 elongated,abruptly raised plates.Genotype.—Hemkystites (Cystaster) granidatiis Hall, 1871. Or-dovician (Maysville) of Ohio.CINCINNATIDISCUS, n. gen.{Hcinicystites of authors not Hall)Like Cystaster except that the theca is not sacklike but depressed,attached, and that the interambulacral plates are squamose and imbri-cate distinctly, divided into larger central plates and a marginal zoneof small nodose ones. Anal pyramid of nodose plates.
4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93Genotype.—Agelacrimis (Hemicystites) stellatiis Hall, 1866. Or-dovician (Maysville) of Ohio. Hemicystites carnensis Foerste, 1914,belongs to this genus.CARNEYELLA Foerste, 1916Theca typically elevated, sacklike, attached by narrow basal partbut also may occur as a thin circular expansion. Ambulacra curved,four (1-4) to left and one (5) to the right, with two rows of coveringplates elevated and alternating with each other along the middle Hne.Oral area composed of three plates, one large and two small. Analarea of many small plates radially arranged. Surface of plates orna-mented with minute pits and nodes.Genotype.—Agelacrimis (Lepidodiscus) pilens Hall, 1866. Ordo-vician (Maysville) of Ohio. Carneyella vetusta Foerste, 1914, isrelated to C. cincinnatiensis, n. sp., next described. Carneyella valcou-rensis Clark, 1920, is doubtfully referred here.CARNEYELLA CINCINNATIENSIS, n. sp.Plate I, fig. 10Agelacrimis (.Lepidodiscus) cincinnatiensis Hall (not Roemer), Descr. newspecies fossils Cincinnati, Ohio, p. 214, pi. 2, fig. 7, 1871 (advance sheets,p. 6, 1866) ; 24th Rep. New York State Cab. Nat. Hist., p. 214, pi. 6, fig. 7,1872.This well-marked species, erroneously referred to Agelacrimis (nowIsorophiis) cincinnatiensis Roemer, is readily distinguished from thatform by its thin, depressed, almost flat theca attached by its entireaboral portion. Furthermore, the ambulacral plates are less elevated,all the plates are rather papillose, and there are only three oral plates.Occurrence.—Maysville division (Corryville beds) of the (3rdo-vician, Warren County, Ohio.Holotype.—U.S.N.M. no. 40743.ISOROPHUS Foerste, 1916Theca depressed, circular, attached by the entire under surface.Ambulacra composed of two rows of plates with an intercalated seriesoften present, more or less curved, four (1-4) to the left and theright posterior (5) to the right. Oral area occupied by numeroussmall plates. Margin composed of numerous rows of small platesslightly increasing in size inward. Interambulacral plates polygonal,becoming slightly imbricated. Anal area a circle of triangular platesregularly arranged.
NO. 8 EDRIOASTEROIDEA BASSLER 5Genotype.—Agelacrinus cincinnaticnsis Roemer, 185 1. Ordovician(Maysville) of Ohio, etc. Other species of Isorophus are Agela-crinus austini Foerste, 1914, A. fabcri Miller, 1894, A. -imrrcnensisJames, 1883, and A. holhrooki James, 1878.ISOROPHUSELLA, n. gen.Like Isorophus but ambulacra i, 2, and 3 directed to the left and 4and 5 to the right, and the interambulacral plates strongly imbricating.Genotype.—Lebetodiscus inconditiis Raymond, 191 5. Ordovician(Trenton) of Ontario, Canada.ISOROPHUSELLA INCONDITUS (Raymond)Plate I, fig. IILebetodiscus inconditus Raymond, Ottawa Nat., vol. 29, pi. i, fig. i, 1915-Theca a thin, slightly convex, circular disk, attached to or restingupon a limestone bed by its entire aboral surface, about 20 mm indiameter, exhibiting on its oral face a broad peripheral band of minute,closely imbricating plates, five ambulacral areas of which the oral por-tion is composed of many small irregular, angular plates, and eachambulacrum has two rows of covering plates alternating with eachother and frequently developing additional small accessory platesalong the midline between them. Ambulacra short, rather broad,three (1-3) curving to the left and two (4, 5) to the right. Inter-ambulacral areas of larger, narrow, strongly imbricating plates. Analarea rather distinct, consisting of 10 elongate triangular smooth platesin one circle meeting at the center but not rising above the generalsurface.Although very similar to species of Isorophus, this interesting formis readily distinguished by the different arrangement of the ambulacra.Occurrence.—Trenton limestone, Hull, Quebec.Plesiotype.—U.S.N.M. no. S.3871, Springer Coll.STREPTASTER Hall, 1872Theca as in Carneyella, except that the ambulacra all revolvestrongly toward the left and are composed of highly elevated plates.Interambulacrals are small, polygonal, mosaic plates, 0.5 to i.o mm indiameter.Genotype.—Agelacrinus vorticellatus Hall, 1866. Ordovician(Maysville) of Ohio. 5*. reversatus Foerste, 1914, and vS. septem-hrachiatus Miller and Dyer, 1878, are other species of Streptaster.
6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93LEBETODISCUS Bather, 1908Theca depressed, circular. Ambulacra curved, live in number, alldirected toward the left, with mosaic interambulacral plates. Am-bulacral plate structure apparently as in Carneyella. Anal area welldefined in slightly wider interradius.Genotype.—Agelacrinites dicksoni Billings, 1857. Ordovician(Trenton) of Ontario, Canada. L. loriformis Raymond. 1915. is asecond described species.FOERSTEDISCUS, n. gen.Like Lebetodiscus, but ambulacra all directed to the right, short,broad, and strongly curved, and interambulacral plates polygonal butoverlapping toward the center and highly imbricating around theperiphery. Anal area of many small, irregularly arranged plates inslightly wider interradial area.Genotype.—F. grand is, new species. Ordovician (Trenton) ofKentucky. FOERSTEDISCUS GRANDIS, n. sp.Plate I, fig. 12Theca a flattened disk, 25 mm in diameter, resting upon or attachedto a layer of limestone. Ambulacra five, short, broad, all curved tothe right, consisting of two rows of elongate covering plates slightlyraised along the midline, and a single row of floor plates. Interambu-lacrals large, imbricating, but flat in the central areas, narrow, morenumerous, and piled up on edge along the margin. Anal area large,distinct, occupying a slightly wider space, composed of many smallimbricating plates arranged in circles, the smallest in the center.Although resembling Lebetodiscus dicksoni (Billings), the right-handed arrangement of the ambulacra in this present species is aready means of separation.Occurrence.—Curdsville division of the Trenton, near Troy, Wood-ford County, Kentucky.Holotype.—U.S.N.M. no. S.3191, Springer Coll.PYRGOCYSTIS Bather, 19 15Oral surface of five broad, straight ambulacra mounted on a highcylindrical turret composed of wide, thin, closely imbricated plates.Genotype.—F. sardesoni Bather, 191 5. Ordovician (Decorah) ofMinnesota. Scalpellum sulcatum, procerum, and cylindricum Aurivil-
NO. 8 EDRIOASTEROIDEA BASSLER 7
lius, 1892, Pyrgocystis octogonaRichter, 1930, P. grayae Bather, 1915.P. ansticei Bather, 191 5, and P. hathcri Ruedemann, 1925, are theother species of this genus.HEMICYSTITES Hall, 1852(Heinicystis Haeckel, 1896)Theca a thin, flattened disk with oral arrangement and pitted platestructure of Carneyella, but ambulacra are short, broad, and straight.Anal pyramid elevated and composed of a circle of triangular platesregularly arranged.Genotype.—H. parasitica HaW, 1852. Silurian (Rochester) of NewYork. Agelacrinites hellulus, bohemicus, confertus, latinscuius, sim-plex, tener, and velatus of Barrande, 1887, A. rectiradiatiis Shideler.1918, and Agelacrinus hillingsi Chapman, i860, Lehetodiscus yoiingiRaymond, 1915, and L. chapnmni Raymond, 1915, are described spe-cies of Hemicystites.THRESHERODISCUS Foerste, 1914Agelacrinitidae with branched ambulacral rays having a pronouncedtrimerous origin. Interambulacrals large, squamose, imbricating incentral part and smaller along border.Genotype.—T. raniosus Foerste, 1914. Ordovician (Trenton) ofOntario, Canada. AGELACRINITES Vanuxem, 1842{Agelacrinus authors; Agelacystis Haeckel, 1895; Haplocystitcs Roemer, 1852;Haplocystis Bather, 1899)Thin parasitic disks attached by entire aboral surface. Ambulacrafive, long, narrow, much curved; two (4, 5) to the right and three(1-3) to the left. Interambulacral plates mosaic and sculptured, al-though slightly imbricating. Periphery formed by several rows ofsmall plates followed by one row of much larger elongate ones. Analarea a circle of triangular, regularly arranged plates.Genotype.—A. hamiltonensis Vanuxem, 1842. Devonian (Hamil-ton) of New York. A. ephracniovianus Bogolubov, 1926, A. hanoveriThomas, 1924, and A. rhenanus Roemer, 1851, from the Devonian,and A. blairi Miller, 1894, A. legrandensis Miller and Gurley, 1894,from the Mississippian are referred to this genus.
8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93DISCOCYSTIS Gregory, 1897(EchiiiodiscHs Worthcn and Miller, 1883 (not Agassiz) ;Agcladiscus Miller, 1897)Like Agelacrinites except that four ambulacra are curved to leftand one, the right posterior (5), to right, and that body is well de-veloped and sacklike with many rows of elongate, narrow marginalplates.Genotype.—Echinodiscus optatus Worthen and Miller, 1883 = !).(Agelacrinus) kaskaskiensis Hall, 1858. Mississippian of Illinois.Echinodiscus sampsoni Miller, 1891, is another species of this genus.COOPERIDISCUS, n. gen.Body depressed globular, free, entirely covered with plates ; ambu-lacra long, very narrow, much curved, all turning to the right. Inter-ambulacral plates strongly imbricate. Anal pyramid of regular tri-angular plates meeting at a point.Genotype.—Lepidodiscus alleganius Clarke, 1901. Devonian (Che-mung) of New York.LEPIDODISCUS Meek and Worthen, 1868Like Coaperidiscus but ambulacra 1-4 curve strongly to the left and5, the right posterior one, to the right. Interambulacral plates small,strongly imbricating. Anal pyramid well developed.Genotype.—Agelacrinites squainosus Meek and Worthen, 1868.Mississippian. Agelacrinites heecheri Clarke, 1901, A. buttsi Clarke,1901, Lepidodiscus Ichouri Sladen, 1879, and L. niilleri Sharman andNewton, 1892, are the known species of this genus.ULRICHIDISCUS, n. gen.Body semiglobose with the oral side occupied by five narrow butwell-defined, very long ambulacra all strongly curving to the left,with a well-defined anal pyramid of many long triangular plates inone circle, and interambulacral areas composed of polygonal butslightly imbricating plates.Genotype.—Agelacrinus pulaskiensis Miller and Gurley, 1894. Mis-sissippian (Chester) of Kentucky.Family EDRIOASTERIDAE BatherTheca flexible, depressed, usually globular, attached by the smallcentral excavated part of the aboral surface ; ambulacra strongly
NO. 8 EDRIOASTEROIDEA BASSLER 9
curved and passing on to aboral surface ; floor plates arranged in twoseries, one on each side of the ray, and alternating along the medianline. EDRIOASTER Billings, 1858(Cyclastcr Billings, 1857, not Cotteau, 1856; Agclacrinites Forbes, 1848,not Vanuxem; Edriocysfis Haeckel, 1896; Aesiocystites Miller andGurley, 1894; Aes'wcystis Bather, 1900)Sacklike, flexible theca attached by a small central portion of theaboral surface and with the ambulacra passing from the oral to aboralsides. Interambulacral plates mosaic. Ambulacra strongly curved,four (1-4) to the left and one (5) to the right, with an anal pyramidcomposed of many small plates, irregularly arranged.Genotype.—Cyclaster bigshyiWxWmgs, 1857. Ordovician (Trenton)of Canada. Agelacrinites huchianus Forbes, 1848, Edrioaster levisBather, 1914, E. saratogensis Ruedemann, 1912, and Aesiocystitespriseus Miller and Gurley, 1894, are other species of this genus.DINOCYSTIS Bather, 1898Oral surface convex, with five narrow ambulacra all strongly curvedto the left and aboral surface composed of a thin flexible integumentof narrow imbricating plates with a small central orifice for attachment.Genotype.—D. barroisi Bather, 1898. Devonian of Belgium.
Family CYATHOCYSTIDAE BatherEdrioasteroidea in which the aboral portion consists of a fused solidmass of plates attached permanently to some foreign object.CYATHOCYSTIS Schmidt, 1880Theca with oral surface much as in Stromatocystites but mountedupon a solid fused mass of stereom and permanently attached at theaboral end.Genotype.—C. plaiitini Schmidt, 1880. Ordovician (Echinosphe-rites limestone) of Estonia.CYATHOTHECA Jaekel, 1927Like Cyathocystis, except that the ambulacral areas are apparentlyvery narrow, practically hidden at the surface.Genotype.—C. suecica Jaekel, 1927. Ordovician of Sweden.
lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93POSITION UNCERTAINFamily ASTROCYSTITIDAE, new name(Steganoblastidac Bather)ASTROCYSTITES Whiteaves, 1897(Steganoblastits Whiteaves, 1897)Regarded l^y Bather as an edrioasteroid and by Hudson as ablastoid.Family CYCLOCYSTOIDIDAE S. A. Miller, 1889(order uncertain)Genera Cyclocystoides Billings and Salter, 1858; NarraivaycUaFoerste, 1920; Savagella Foerste, 1920.EXPLANATION OF PLATEFig. I. Walcottidiscus typicalis. new genus and species. The holotype, X 3, acrushed theca showing the oral side. Middle Cambrian (Burgessshale) Burgess Pass, near Field, British Columbia.Figs. 2, 3. Carncyella (Agclacrinus) pileiis Hall, 1866. View of oral side oftheca and lateral view, X 2, showing the sacklike form. Maysville(Fairmount formation) : Cincinnati, O'hio.Fig. 4. Cystaster (Hemicystites) gramdatus Hall, 1871. Side view, X 2, ofthe elongate theca. Maysville (Fairmount formation) : Cincinnati,Ohio.Fig. 5. Streptaster (Agelacrinus) vorticcUaius Hall, 1856. Oral side of thecaslightly enlarged, exhibiting the elevated ambulacra all revolvingtoward the left. Maysville (Fairmount formation) : Cincinnati,Ohio.Fig. 6. Cincinnatidiscus (Agelacrinus) stetlatus Hall, 1866. Oral side of thedepressed, attached theca, with straight arms, X - Maysville (Fair-mount formation) : Cincinnati, Ohio.Fig. 7. Ulrichidiscus (Agelacrinus) pulaskicnsis Miller and Gurley, 1894. Viewof the semiglobose theca, natural size, showing strong curvature ofall ambulacra to the left. Chester (Glen Dean formation) : PulaskiCounty, Ky.Fig. 8. Pyrgocystis sardcsoni Bather, 1915. Side view of theca, X I2, showingthe solid basal portion of many imbricating plates surmounted bythe oral surface. Black River (Decorah) shales: St. Paul, Minn.Fig. 9. Coopcridiscus (Lepidodiscus) alleganius Clark, 1901. Oral side of thefree, globular theca, X I2, exhibiting the very narrow ambulacra allcurved to the right and the highly imbricated interambulacral plates.Chemung formation : New York.Fig. id. Carneyclla cincinnatiensis, new species. View of the attached, thin cir-cular theca with ambulacral structure of Carneyella, X 4- Maysville(Corryville formation) : Warren County, Ohio.
NO. 8 EDRIOASTEROIDEA BASSLER II
Fig. II. Isorophitsclla inconditus (Raymond, 1915). Example, X 4, a depressedcircular expansion with the plate structure of Isorophus but with 3of the ambulacra directed to the left and 2 to the right. Trentonlimestone : Hull, Quebec, Canada.Fig. 12. Foerstcdiscus grandis, new genus and species. The holotype, X 2, aflat circular expansion with the ambulacra all directed toward theright. Trenton (Curdsville limestone) : Near Troy, WoodfordCounty, Ky.

SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93, NO. 8, PL. 1
Edrioasteroidea(For explanation, see page lo.)