Bm'^^^y^&mmm^m i'-;a /iJ^.V-'v VQMW '¥Vvu' i^vwVki^,^ .s':^^,^^^K^^; >}^^^^ ,^'oy^'\,vV^ kXKC3 VM^^' ■■«^,^;!^i^„S],Sfc««/Mt^r^.J^- y^^ v^w^y^AA'^^U ]j^^y^' /// ^ibrarg of tb l^uscuni OF COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE, CAUBRIDGE, MASS. The gift of '^AiMJxmJTLA ^AoM. VM^mjOiV jf4.^J^^ f^ o j/oji^- f 7^ ^/;^ BULLETIN NO. 6 OF THE Illinois State Museum OF NATURAL HISTORY DESCEIPTION OF NEW SPECIES OF PALEOZOIC ECHINODERMATA. ^JUxlLj By S. a. MILLER and Wm. F. E. GURLEY. Speingfield, Illinois, Apkil 5, 1895. SPRINGFIELD, ILL. Ed. F. Habtmann, State Pbintbr. 1895 BULLETIN NO. 6 OF THE . o^_^ "USEUM itli Compliments of Prof. WM. F. E. GURLEY, STATE GEOLOGIST, R V SPRlNGFItLU, ILLINOIS, U. S. A. DESCKIPTION OF NEW SPECIES OF PALEOZOIC ECHINODERMATA. By S. a. MILLER and Wm. F. E. GURLEY. Spkingfield, Illinois, April 5, 1895. SPRINGFIELD, ILL. Ed. F. IIartmann, State rEiNnsn. 1895 BULLETIN NO. 6 OF THE Illinois State' Museum OF NATURAL HISTORY DESCRIPTION OF NEW SPECIES OF PALEOZOIC ECHINODERMATA. By S. a. miller and Wm. F. E. GURLEY. Springfield, Illinois, April 5, 1895. SPRINGFIELD, ILL. Bd. F. Habtmann, State PBiNTEn. 1895 ILLINOIS STATE MUSEUM OF Natural History SPRINGFIELD, ILLINOIS. Board of Trustees. John P. Altgeld, Governor. William H. Hinbichsen, Secretary of State. S. M. Inglis, Superintendent Public Instruction. George Walter Murray, Secretary. William F. E. Gdblev, State Geolotjisl and Vundor, DESCRIPTION OF NEW SPECIES OF PALJ30ZOIC ECHINODERMATA. BY S. A. MILLER AND WM. F. E. GURLEY. SUBKINGDOM ECHINODERMATA. CLASS CRINOIDEA. ORDER PAL^OCUINOIDEA FAMILY ACTINOCRINID.E. BATOCRINUS SPINOSUS, D. sp. Plate I, Fig. 1, azygous side; Fig. 2, opposite view; Fig. 3, basal view of the same specimen, azygous side down. This species is above medium size. The calyx is short, three times as wide as high, subpentagoiial in outline. The vault is high and inflated. All the plates of the body are produced in wedge-shaped, irregular spines, part of which are broken off our specimen. Basals short and forming a low, Suucer-shaped cup, with a mod- erately concave depression below, for the attachment of the column. First primary radials twice as wide as long, and each bearing a transverse, wedge shaped spine, directed downward, that extends lower than the facet for the columnar attachment. Second prim- ary radials short, about three times as wide as long, quadrangu- lar. Third primary radials, wider than long, pentagonal, axillary, and in four rays there is a single secondary radial upon one su- perior sloping side which is axillary and bears upon each upper side three tertiary ralials, anil upon the other superior side there are three secondary radials, which arrangement gives to each of the four rays three arms. In the ray opposite the azygous area, the third primary radial bears upon each upper side three second- ary radials and consequently has only two arms. There are, there- 6 fore, fourteen arms, in this species, and fourteen ambulacra! open- ings to the vault. The regular interradial areas are not exactly alike. In two of them there is a single plate and in the other Iwo areas a small plate follows the first one. In the azygous area, the first plate is in line with the first radials and it is followed by three plates of nearly equal size, giving to this area a subqiiadrate outline. The vault is enormously developed, most tumid opposite the azygous area and covered with large, polygonal, unequal, and re- markably heavy spinous plates. The proboscis is large, subcentral and slightly curved back from the azygous side. There are two pores that penetrate the vault between each of the arms or twenty- eight of these passages in the species. This species is distinguished by the development of each radial series at the periphery of the calyx which gives to the calyx its subpentag )nal outline; by the great development of the vault; by the robust spinous plates and fourteen arms. It has some resem- blance to Eretmocrinus prtvgravis, which is a twelve armed spe- cies and has more plates in the azygous and regular areas. It may be said to be constructed upon a similar plan, though not to be mistaken for that sfjecies. We think that Eretmocrinus priv- cjravis should be referred to Balocrinns, and possibly the genus Eretmocrinus abandoned, at least, the large proboscis, no matter how much it may bd curved, will not alone distinguish Eretmocri- nus. Found by Prof. A. G. Wetherby, in the Keokuk Group, on Little Barren Kiver, Kentucky, and now in the collection of Wm. E. E. Gurley. BATOCRINUS CUKI08US, n. sp. Plaie I, Fig. 4, azygous side; Fig. 5, opposite view; Fig. 0, hasal view. Species large, vault exceeding the calyx in dimension. Calyx more than twice as wide as high, truncated below, regularly expand- ing to the first tertiary radials, and then spreading nearly horizon- tally to the free arms. Ambulacral openings directed horizontally. Each primary, secondary, tertiary and quaternary radial series consists of a sharp ridge that slopes laterally to the sutures, the sharp angularity increases from the first primary to the last qua- ternary plate, each plate also bears a sharp central node or tuber- cle. All other plates of the calyx are tumid and each bears a central node. Surface granular. Column large and contains a large canal. Basals very short, wide, truncated below, lateral sutures deep, superior face of each concave, truncated face about twice the di- ameter of the column, the facet for which is only modeiately concave and radiately furrowed. First primary radials of un- equal size, from two to four times as wide as long, superior face concave, three hexagonal, two heptagonal, and each bears three nodes, one central from which the angular radial ridge arises, and one on each prolonged lateral side. Second primary radials of uneqiial size, from one and a half to two and a half times as wide as long, quadrangular. Third primary radials about one half larger than the second, pentagonal, axillary and support on each upper sloping side, two secondary radials. The secondary radials are as large as the second and third primaries. The second sec- ondary radials are axillary, and, in three rays, bear upon one of the superior sloping sides two tertiary radials, the second one of which is axillary and bears upon each superior sloping side three quaternary radials, and upon the other side of the second sec- ondary radials, which are the proximal sides, four tertiary radials, which arrangement gives to each of the three rays six arms. In the ray opposite the azygous area and in one of the lateral rays each second secondary radial is axillary and bears upon each upper sloping side four tertiary radials, and consequently these rays have four arms. Thei-e are, therefore, twenty-six arms in this specifs and twenty-six ambulacral openings to the vaidt. There are no intersecondary or intertertiary plates. In two of the regular interradial areas tliere is one large plate followed by a .small one, and in the other two areas tl'ere is a large plate followed by two small ones. These plates are tumid and each bears a central node. The azygous area is somewhat trapezoidal in outline and contains seven plates. The first one is in line with the first primary radials, but is much larger than either of them and bears a large transverse wedge-shaped spine. It is followed by three tumid, nodose plates in the second range, and these, in turn, by two plates, one of which is quite small, and above the larger plate, in the third range, there is a small plate in the fourth range, which is immediately below the angle formed by the union of the first quaternary plates. Vault high, broadly rounded, most tumid opposite the azygous side and covered with polygonal, nodose plates. The larger plates bear two, three or more nodes, but the smaller ones bear a single cimtral noile. The proboscis is subcentral on the azygous side. There are narrow, elongated plates at the base of the vault, be- tween the plates covering the ambulacral furrows,- except between 8 Ihe furrows beloEgiuj? to the quaternary series of radials, and at the inferior angles of these elongated plates there are pores pene- trating the vault, making, in all, forty of these so-called ovarian orifices. This species is distinguished by its general form, sharp radial ridges, tumid and nodose plate?, and twenty-sis arms. It is not necessary to make any special comparison with any heretofore de- scribed. Found by Prof. A. G. Wetherby in the Keokuk Group, iu Allen County, Kentucky, and now in the collection of Wm. F. E. Gurley. BATOCEINCS CASULA, n. sp. Plale I, Fig. 7, azygous view; Fig. 8, side view of ihe same specimen, part being broken away opposiie ihe azygous side Species large, calyx and vault subequal in size. Calyx one-half wider than high, bowl-shaped, most rapidly expanding above the secondary radials, and ambulacral openings directed nearly hori- zontally. Radial ridges angular and in the tertiary and quater- nary series embracing the entire plates to the lateral sxitures, and each plate bears a central node. All the plates of the calyx are tumid and each bears one or more nodes. Surface granular. Column large. Basals short, twic^e as wide as high, bear a tubercle at each side, and form a low hexagonal disc, one-half wider than the column, each superior face concave and lateral sutures deep. First primary radials of une(iual size, from one-half wider to twice as wide as long, superior face transverse or slightly concave, three hexagonal, two heptagonal and each bears a central node, and the larger ones have small lateral nodes. Second primary radials comparatively small, (quadrangular, and about one-half wider than liigh. Third primary radials about one-half larger than the second, pentagonal, axillary, and support on each upper sloping side two secondary radials, and in one of the ra} s in our specimen there are three secondary radials. The secondary radials are larger than the second and third primaries, and the last one is axillary in all the rays. Above this some of the rays are injured in our specimen. The lateral ray shown in figure S has fjur tertiar}' radials upon each upper sloping side of the last scctmdaries w'hich gives to this ray four arms. The ray shown on the right of the azygous area in figure 7 has four tertiary radials on each of the upper proximal sides of the second secondaries, and two tertiary radials on each of the upper distal sides, the last of which is axillary and supports upon each upper side three quaternary radials, 9 which arrangement gives to this ray six arms. The species evi- dently has either twenty-four or twenty-six arms. The arras are in clusters of two or three that project and have depressed inter- spaces, that are most conspicuous on the vault, but give a very irregular outline to the top of the calyx. In each of the regular interradial areas there are four plates. The first is very large: it is followed by two plates of unequal size, and above these there is a smaller one. The azygous area is much elongated and contains seven plates. The first one is in line with the first primary radials, and nearly as large as any of them. It is followed by three plates sub-equal in size and about as large as the first. These are followed by two plates, one quite small and the other about as large as those in the second range. Above these there is an elongated plate in the fourth range that sends an angle high between the quaternary radials, and to near the top of the calyx. The vault is convex, irregular, depressed in the interradial areas and covered with remarkably large, polygonal, peculiar, nodose plates, dome of the plates bear a large, wedge-shaped spine; others bear one, two or three nodes, more or less irregularly de- fined. The proboscis is subcentral, but broken off in our speci- men. Three elongated plates with nodes near the upper end may be seen over the azygous ai'ea in figure 7, and two orifices pene- trating the vault at their lower angles. One elongated plate may be seen in figure 8 separating the four armed series with two orifices penetrating the vault at the lower angles. And the plate separating the four armed from the six armed series is one-half longer than either one shown in the illustrations. Two pores pene- trate the vault between each of the arms, except the quaternary series, and, therefore, there are forty of these so-called ovarian orifices. This species bears more resemblance to Balocriniis riiriosuft than to any other heretofore described, though the vault differs so much from that, it will be wholly unnecessary to institute any coDparisou. The difference in the form of the calyx in the two species will account for the variations in the size and shape of the plates so far as the basal and radial series extend, but the differences in the number of interradials and shape of the areas will always constitute specific characters. The sharp radial plates in B. cnriosns and depressed spaces between the bunched radial series in this species are not to be overlooked. Found by Prof. A. G. Wetherby in the Kejkuk Group, on Little Barren River, in Kentucky, and now in the collection of Wm. F. E. Gurley. 10 BATOCRINDS HONOBABILIS, n. Sp. Plate I, Fig. 0, azijcjons view; Fig. 10, opposite side same specimen. Species larf>e, with a vault less than half the height of the calyx. Calyx nearly as long as wide, hexagonal below and most rapidly expanded near the top. Plates tumid and subspinous, Ambulacral openings directed upward at an angle of thirty degrees. Column large and radiately furrowed. Basals stand upright and form a hexagon about twice as wide as high and about twice as wide as the diameter of the column. They are beveled towards the sutures and flattened on the sides and extend to wedge-shaped end below the commencement of the column, so that the calyx will stand on the cuneiform edges. First primary radials large, nearly as long as wide, three hexagonal, two heptagonal. Second primary .radials a little wider than long, quadrangular. Third primary radials abut upon two interradials at one or both ends, and consequently four of them are hexagonal and one heptagonal; the heptagonal plate is shown in figure 10. They are very unequal in size, but each one is axillary and sup- ports upon each of its two superior sides two secondary radials. The secondary radials are rather long and as large as the second and third primary radials, the second secondary radials are axil- lary and each supports on its superior sloping sides three tertiary radidals, and in some rays four tertinry radials. By this arrange- ment there are four arms in each radial series or twenty arms and twenty ambulacral ojjenings to tlie vault in this species. There are no intersecondary or intertiary plales. The regular interradial arms are much elongated and the two shown in figure 10 have each four plates, one in the first range, two in the second and one in tlie third. But in each of the other regular interradial areas there are three plates in line, tiie third one being the smallest. In the azygous area there are seven plates and it is somewhat trapezoidal in outline. The first one is as long as wide, larger than a first primary radial and in line with them. It is followed in the second range by three large plates and these by two in the third range aud one in the fourth, which separates the first tertiary radials, and in these rays there are four tertiary radials. The vault is subhemispherical or broadly rounded and bears a small subcentral proboscis which is liroken oil' in our specimen. It is covered with large, tumid, polygonal plates, each of whicli bears a central mode. The interradial areas are slightly depressed between each pair of arms where there is an elongated plate and 11 an orifice at each of its inferior angles. This arrangement places one pore on one side of each arm or gives to the species twenty of these so-called ovarian pores. This species is distiuguished by its general form, cuneiform basal plates, elongated interradial areas, twenty arms and nodose plates. It cannot be mistaken for any hitherto described. Found by Prof. A. G. Wetherby, in the Keokuk Group of Ten- nessee and now in the collection of VVm. F. E. Gurley. lUTOCRINUS WETHERBYI. PUde I, Fig. 11, az>j(]ous view; Fig. 12, opposite side of same specimen. The oider rim of the hasals is broken off. Species rather above medium size, biturbinate vault larger than the calyx. Plates of the vault tumid and nodose, while those of the calyx are smooth. Calyx twice as wide as high, truncated and expanded at the base, and broadly constricted in the region of the secondary radials, and having the last tertiary radials directed nearly horizontHlly. The surface is without radial ridges or other ornamentation except a granular covering. TLe basals are truncated below and broadly expanded, but the outer rim is broken off in our specimen "so the true diameter is not disclosed. The column is large aud inserted in a concave rad- iately furrowed depression. Tbe first primary radials are very short, from three to four limes as wide as long, i-uperior face concave, three hexagon-il and two heptagonal. Second primary rad- ials short, from two to three times as wide as \<>nj:, quadrangular. Third primary radials very little larger thin the second, pentag- onal, axillary and supports on each superior sloping side two secondai-y radials. The secondary radials are larger than tlie sec- ond and third primary radials and considerably wider. The second secondary radials are axillary and bear on each superior sloping side two rather long tertiary radials. By this arrangement there are twenty arms and tweutj' ambulacral openings to the vault. There is a single very large plate in each of two regular inter- radial areas and two plates in each of the other two areas, one rather large plate followed by a small one as shown in figera 12. There are five azygous plates. The first one is much larger than either of the first primary radials and in line with them. There are three plates in the second range, the middle one being much the smallest and quadrangular. There is a single wide plate in the third range which is nearly as large as the first. The azygous area is, therefore, nearly square iu outline, with a small quad- rangular plate in the center surrounded by four plates in the angles of the area. 12 The vault is liigh, subconical with a large subcentral proboscis. It is covered with large, tumid, nodose, polygonal plates. The interradial areas are slightly depressed between each pair of arms, where there is a narrow elongated plate and an orifice at each of its inferior angles. This arrangement places one pore on one side of each arm or gives to the species twenty of these so-called ovariau apertures. This species is distinguished by its general biturbinate form, expanded basals, smooth calyx, nodose vault, square azygous area and twenty arms. It is a marked species that need not be mis- taken for any heretofore described. Found by Prof. A. G. Wetherby, in whose honor we have proposed the specific name, in the Keokuk Group, at White Creek Springs, in Tennessee, and now in the collection of Wm. F. E. Gurley. BATOCRINUS LATERNA, n. Sp. Plate I, Fig. 13, azijr/ons area on the rigtit ; Fig. 14, basal vieio to sliow titc diameter of tlie basal plates. Species rather above medium size and having a lantern shape that suggested the specific name. Vault conical and lai-ger than the calyx. Calyx more than twice as wide as high; basals thin and remaikably expanded in a circular disc; each radial series consists of a sharp ridge that slopes laterally to the sutures, while the interradial areas are flattened and depressed so that a transverse section of the calyx, at any [)oint below the secondary radials, will be sharply pentagonal in outline. The calyx is ab- ruptly expanded above the secondary radials so that the last tertiary radials are directed horizontally, in pairs, with a depress- ed interradial space between them. The angularity of the radial ridges is somewhat like it is in Batocrinits c/(r('o.s».s, but otherwise the calyces have no resemblance to each other. The basals form a thin circular disc that has a diameter one- half greater than the height of the calyx, and, in the center of which, on the lower flat side, there is a concave radiately furrow- ed depression for the attachment of the column, and a small round columnar canal. The diameter of the column is about one- fourth the diameter of the basal disc. The first primary radials are short, two or three times as wide as high, have a concave face for the second ratlials, are longitudinally shaiply angular in the middle, and appear as if set down upon the surface of the plane basal disc. Second prin:ary radials short, sharply angular in the middle, quadrangular. Third primary radials very little larger 13 than the second, pentagonal, axillary and bear upon each superior lateral side two secondary radials. The secondary radials are short, the last one axillary and supporting on each superior slop- ing side three tertiary radials. This arrangement gives to the species twenty arms and twenty amhulacral openings to the vault. The amhulacral openings are directed horizontally. The regular interradial areas are depressed and flattened below the base of the radial ridges. Some of the matrix covers the plates in some of the areas so that they cannot be distinguished. In the area, on the loft of figure 13, there are three plates, one in the first range and two in the second, one of which is much longer than the other. In the azygous area there are five plates. The first one is in line with the first primary radials, only about half as wide but somewhat longer than either one of them. It appears to stand un on the circular disc filling the middle part of the depressed and flattened area. It bears a small • entral tubercle, but all the other iuterradials are flat and smooth. It is followed by three rather large flat plate3, in the secoud range, and above these, in the third range, there is a single, narrow, elongated plate that extends one angle high between the second tertiary plates, but is cut ofl' from reaching the plates of the vault. Vault very high, conical, larger than the calyx and bearing a large subcentral proboscis. The interradial areas are depressed between each pair of arm bases. The vault is covered with large, polygonal, and tumid plates, each one of which bears a lar^e central node. There is a narrow elongated plate between each pair of amhulacral furrows and an orifice at each of its inferior angles. This arrangement places one pore on one side of each arm or gives to the species twenty of these so-called ovarian apertures. The large round basal disc, pentagonal outline of the calyx, sharp radial ridges, depressed and flattened interradial areas, conical vault and twenty arms distinguish this species. There is no doubt but that the probossis is large and long and that the basal disc is expanded, probably, beyond any other known species. Both of these characters are ascribed to Eretmuci iiiiis, but there is no difliculty in showing, as we have before remarked, that the proboscis, alone, cannot be relied upon to distinguish the genera. Th'^' basal plates cannot be relied upon, for you may pass by a graded scale from the extraordinary basals, in this species, to those in Baiocrinus weihevhyi and then to Batocriims curiosus and then io Baiocrinus casula where the basals are rounded instead of ex- panded. The only other character by which Eretmocrinus is dis- 11 tinguisbed from Batocrinus is found in the arms, and, as we shall have occasion to describe a species, in this paper, having the flat- tened arms belonging to Eretmocrinus, we will defer further com- pai'ison until that species is before us. If Ereimocrinus, however, is a valid genus, the probability is, that this species should be re- ferred to it, in the absence of a knowledge of the arms, for, oth- erwise, the genus can only be known by the arms, which are rarely ever found, in chert or among silicified specimens. The species most nearly related to this one is Ereimocrinus lyonanus, though tiiey are readily distinguished by the basal plates and in- terradial areas; differences, however, which are only specific, not generic. They both belong to the same genus. Found by Prof. A. G. Wetherby, in the Keokuk Group, at White Cret^k Springs, Tennessee, and now in the collection of Wm. F. E. Gurley. BATOCEINUS LACINIOSUS, U. Sp. Plate 1, Fig. 15, view opposite the azygous area; Fig. 1(>, azy- (jous side of same specimen. Species medium size, one of our specimens is much smaller than the one illustrated. General ,form bitnrbinate; vault larger than the calyx. Calyx twice a-^ wide as high, broadly truncated below and rapidly expanding from the secondary radials so as to direct horizontally the last tertiary radials and ambulacral openings. Plates on he lower part of the chIvx tumid and subspinous, those on the superior part plane or slightly convex. Radial ridges un- defiued; sutures distinct. Basals form a low hexagonal disc, one-half wider than the diameter of the column. Columnai depression concave and radi- ately furrowed, canal small. First primary radials large, only a little wider than long and each bears a robust, transverse, cunei- form node, three hexagonal, two heptagonal. Second primary radials very small, short, about twice as wide as long, quadrangu- lar. Third primary radials about one-half larger than the second, pentagonal, axillary, and in the rays adjoining the azygous area, bearing on the distal sloping sides three secondary radials and on the proximal sides one secondary radial, which is axillary, and bears upon its superior sloping sides three tertiary radials, which gives to each of these rays three arms. In the two lateral rays the third primary radials bear upon each superior sloping side a single secondary radial, which is axillary and bears upon each upper sloping side three tertiary radials, which gives to each of 15 these rays four arms. In the ray opposite the azygous area the third primary radial bears upon each upper sloping eide three secondary ratliais wliich gives to this ray two arms. There are. therefore, in this species, sixteen arms and sixteen ambulacral openings to the vault. There is a single large tumid plate in each regular interradial area. In the azygousarea there are six plates. The first one is as large as a first primary radial, and in line with them, and bears equally as robust and cuneiform a spine. It is followed by three much smaller plates, in the second range, and these, in turn, by two plates, the lower one of which is much the smaller. The vault is conical, larger than the calyx and bears a subcen- tral proboscis. It is covered with large subspinous plates. There is an elongated plate between each pair of arms and one dividing the three armed rays that separate the ambulacral coverings at the base of the arms and a pore penetrates tlie vault at each in- ferior angle of these narrow- plates, which arrangement gives to this species eighteen of these so called ovarian apertures. This species is distinguished by the general form, tumid plates on the lower part of the calyx and smooth plates in the superior part, azygous area and sixteen arms. Found by Prof. A. G. Wetherby in the Keokuk Group, of Ten- nessee, and now in the collection of Wm. F. E. Gurley. li.\TOCRINUS CASUALfS, n. Sp. Plalc I, Fig. 17, vieio opposite the azyyons area: Fig. IS, azij- goiis view of same specimen. Species below the average si/.e, biturbinate, vault and calyx sub- equal. Calyx broadly truncated below, only slightly expanded above and ambulacral openings directed upward at an angle of forty degrees. Diameter about one fifth greater than the height. Eadial ridges not distinguished. A few of the plates in the lower part tumid, those in the upper part only slightly convex or plane. Basal plates stai:d upright and form an hexagonal disc three times as wide as high, truncated below, and having a deep cavity for the insertion of the column, which is a little less than half the diameter of the basal disc. Columnar canal small. Fir»t pri- mary radials large, one-fourth wider than high, three hexagonal, two heptagonal and each bearing a robust, transverse node. Sec- ond primary radials small, quadrangular. Third primary radials a little larger than the second, pentagonal and axillary. The sec- ond and third primary radials together much smaller than the first. 16 The third primary radials adjoininp; the azygous area bear on the distal slopinp; sides two secondary radials aud on the proximal sloping sides one secondary radial which is axillary and bears upon its superior sloping sides two tertiary radials which gives to each of these rays three arms. In the two lateral rays the third pri- mary radials bear upon each superior sloping side a single sec- ondary radial, which is axillary and bears u-pon each upper sloping side two tertiary radials, which gives to each of these rays four arms. In the ray opposite the azygous area the third primary radial bears upon each upper sloping side two secondary radials, which gives to this ray two arms. There are, therefore, in this species, sixteen arms and sixteen ambulacral openings to the vault. There is a single, rather large, convex plate in each regular in- terradial area. In the azygous area there are four plates. The first one is in line with the first primary radials, though much smaller, and bears a central node. It is followed by two plates in the second range and one in the third, giving to the area a sub- quadrate outline. The vault is conoidal, covered with tumid, polygonal plates and bears a subcentral proboscis. There are a few of the so-called ovarian apertures but they cannot be accurately determined in our specimen. This species is distinguished by its general form, surface orna- mentation, azygous area, and sixteen arms. When compared with Baiocriniis laciiiiosus it will be noticed that the calyx is much longer and yet has one plate less in the secondary and tertiary series, beside the other ditl'erences. It belongs to one of the forms sometimes referred to Ercimocriniis, but we see no suliicieut reason for so classifying it. Found by Prof. A. G. Wetherby in the Keokuk Crrouf) of Ten- nessee, and now in the collection of Wm. F. E. Gurley. BATOCRINUS AKCULA, n. sp. Plate II, Fig. o, (izjjcjous side; Fiq. i, siiDimit view; Fiy. ■'>, basal view of same specimen. Species rather above medium size and having a low calyx and convex vault. Calyx low, saucer-shaped and having a diameter more than four times its height. IJadial ranges not defined and no surface ornamentation. xVmbulacral openings directed horizontally. Sur- face smooth or granular, our specimen being silicified, the granu- lar appearance may or may not represent the surface of the plates. 17 The basals eKtend a little beyond the columu ami form a sub- hexagonal band around the superior end of it, with a concave de- pression radiately furrowed for its attachment. The canal is small and cinque foil. The first primary radials short, about three times as wide as high; three hexagonal, two heptagonal, superior side slightly concave. Second primary radials small, short, (juadrangu- lar, two are three times as wide as high. Third primary radials very little larger than the second, pentagonal, axillary, and on the distal side of the two rays adjoining the azygous area bear two secondary radials, the last of which is axillary and bears two ter- tiary radials on each upper sloping side, and on the proximal side having a single secondary radial, which is axillary and bears three tertiary radials. In each of the two lateral rays there are two secondary radials on each upper sloping side of the third primary radials, the second one being axillary and supporting on each upper sloping side two tertiary radials. By this arrangement there are four arms to each of these four rays. In the ray oppo- site the azygous area the third primary radial bears upon each upper sloping side three tertiary radials which gives to it two arms. There are, therefore, eighteen arms to this species and eighteen ambulacral openings to the vault. In three of the regular interradial areas one large plate is fol- lowed by two small ones, in the other area there are only two plates, one following the other. The azygous area is somewhat triangular or conical aud contains nine plates. The first one is in line with the first primary radials and somewhat smaller. It is followed by three plates of nearly equal size in the second range, and these by three plates in the third range, on the side of the highest of which there is a small plate that might be referred to a fourth range though not extending as high as the middle plate in the third range, and on the apex of the middle plate there is a single plate that extends as high as the calyx and unites with two plates connecting with the vault. The vault is two or three times as large as the calyx, most con- vex or tumid opi)osite the azygous side and covered with large, polygonal plates, each of which bears a central node, except in the azygous interradials where the plates are small and plane or very slightly convex, ft bears a large subcentral proboscis. The arms are arranged in pairs and two pores penetrate the vault be- tween each pair of arms, which gives to this species eighteen of these so-called ovarian apertures. —3 18 This species is distinquished by its form, large azygous area connected with the vault, and peculiar azygous interradius on the vault, and eighteen arms. It cannot be mistaken for any species heretofore described. Found by Prof. A. G. Wetherby in the St. Louis Group, in Washington county, Indiana, and now in the collection of Wm. F. E. Gurley. BATOCEINUS PILEUS, n. sp. Plate II, Fig. 0, basal view slightly brolcen; Fig. 7, summit view; Fig. S, side vieio of the same specimen. This species is rather large in circumference, with an almost flat calyx and moderately convex vault, or plano-convex in outlinp. The cap-like form suggested the specific name. While the calyx is nearly flat, the radial ridges are distinctly convex. Ambulacral openings directed upward at an angle of thirty degrees and not visible in a basal view. Basal plates form a flat disc very little larger than the diame- ter of the attaching column. First primary radials short, more than twice as wide as lou.t4-, three hexagonal, two heptagonal. Second primary radials about two-thirds as large as the first, quad- rangular. Third primary radials nearly as large as the first, pen- tagonal, axillary, and supporting on each upper sloping side two secondary radials. The second secondary radials are axillary and bear upon each superior sloping side three tertiary radials which gives to each ray four arms. There are, therefore, twenty arms in this species and twenty ambulacral openings to the vault. There are three plates in each regular interradial area, one mod- erately large followed by two smaller ones. The azygous area is subovate in outline and contains eiglit plates. The first one is in line with the first primarj' radials and narrower and longer than either of them. It is followed by three plates in the second range and three in the third range, the middle and higher one of which is truncated by a small plate that extends to the top of the calyx and unites with the plates of the vault. The vault is convex and twice as large as the calyx, most tumid opposite the azygous side. There are three large, convex plates over each ambulacral area, one over the place where each pair of ambulacral furrows unite and the other over the point where they all come together. There are also four or more large, convex plates near the base of the proboscis on the side opposite the azy- gous area. The interradial areas are slightly dejjressed and cov- 19 ered with smaller polygonal plates. Most of the sutures beins; destroyed in our specimen, these plates are not indicated in the illustrations. The vault is broken in our specimen so as to show no part of the subcentral proboscis. Two pores penetrate the vault between each pair of arms, which gives to this species twenty of these so-called ovarian apertures. This species is distinguished by its general form, flattened calyx, ovate azygous area connected with the vault, regular distribution of large convex plates on the vault, and twenty arms. It cannot be mistaken for any species heretofore desci-ibed. Found in the St. Louis Group, in Washington county, Indiana, and now in the collection of Wm. F. E. Gurley. BATOCRINUS BDEKETI, n. sp. Plate II, Fig. 9, showing column, calyx and arms, azygous view. This species is rather above medium size and is founded on a single fiQe specimen on a slab. Of course, it does not disclose the entire calyx and as the arms are preserved the vault cannot be seen. The cal\x is nearly twice as wide as high, and subhemi- spherical. Though somewhat lobed in the superior part there are no radial ridges or proper evidences of surface ornamentation. The column is round, med um size, and composed, within an inch of the calyx, of rather thick plates, every alternate one projecting beyond the other; but farther removed from the calyx, the pro- jecting plates are at irregular distances from each other as shown in the illustration. Basals form a low hexagonal cup, more than one-half wider than the diameter of the column and bearing a small rim or truncated bottom which contains the concave depression for the insertion of the column. First primary radials large, a little wider than high, three hexagonal, two lieptagonal. Second primary radials rather large and about one-half wider than high. Third primary radials differ greatly in size, and part are pentagonal and others hexagonal. The one on the left of tiie a/.ygous area is only a little larger than the second primary radial, pentagonal, axillary and bears on one side three secondary radials, and on the other which adjoins the azygous area one secondary radial which is axillary and sup- ports on each upper sloping side two tertiary radials. The arms then bifurcate on the third plate, which gives to this ray six arms. The third primary radial on the right of the azygous area is hexagonal, axillary and bears on the side adjoining the azygous area tsvo secondary radials, and on the distal side two secondary 20 radials, the second one of which is axillary and bears upon each superior side one tertiary radial. The arms then bifurcate on the third plate, which gives to this ray six arms. It will be noticed that these rays are quite differeiit and yet result in producing the same number of arms. The lateral rays, as far as they can be seen, on our specimen, appear to be constructed in the same manner as the two above described. The ray opposite the azygous side may have the same number of arms and it may have two less. We can see seventeen arms, the others are covered. The species, therefore, as near as can be ascertained has either twenty- eight or thirty arms. The arm? are large, long, and composed of a double series of small interlocking plates, that bear long pin- nules. The regular interradial area on the left of the azygous side is elongated, extends to the vault and contains five plates. The first is medium size and re.-ts between the superior sloping sides of two first primary radials; it is followed by two somewhat smaller plates in the second range, and these by one of about the same size in the third range, and this by an elongated plate in the fourth range, that separates the arm-beariDg plates of the calyx and unites with the plates of the vault No other regular area can be described from our specimen. The azygous area is elongate, subovate and contains nine or more plates. The first plate is in line with the first primary radial-t and quite as large. It is fol- lowed by three plates in the second range, and these bj' three in the third range, and these by two plates in the fourth range that separate the arm-bearing plates, and one of which unites with the plates of the vault. This species will be distinguished by its smooth calyx, slightly lobed by the projecting radial series at the summit of the calyx, and depressed iuterradials, that separate the arm-bearing plates; by the shape of the regular and azygous areas and the number of plates which they contain, and their connection with the plates of the vault, which is so exceedingly ran^ in this genus; and by the structure of the radial series and number of arms. We know of no species with which it is necessary to make a comparison, or for which it might be mistaken. Found by Mr. N. K. Burket, in the Keokuk Group, at Hamilton, Illinois, and now in the collection of Wm. ¥. E. Gurley. 21 BATOCRINUS LABELLUM, D. sp. Plate 2, Fig. 10, azygous side; Fig. 11, basal view; Fig. 12, summit view. This species is medium size, depressed, biturbinate or resembling in outline a doable convex; leas. (Jalys and vault subeiiual. Calyx saucer-shaped, about two and a half times as wide as high. Plates convex or transversely ridged, by being beveled toward the sutures, which are remarkably well defined. Ambulacral openings directed upwards at an angle of twenty degrees and not visible in a basal view. The basals extend a little beyond the column and form a sub- hexagonal band around the superior end of it, with a concave de- pression radiately furrowed for its attachment, and in this respect, resembles Balocrinus arcula. First primary radials short, two or three times as wide as long, three liexHgonal, tvo lieptagonal. Second primary radials short, about twice as wide as long, (quad- rangular. Third primary radials a little larger than the second, three pentagonal, two hexagonal, axillary, and in four of the rays supporting upon each upper sloping side two secondary radials, the second one of which is axillary and bears upon each superior sloping side three tertiary radials which gives to each of these rays four arms. In the ray opposite the azygous area the third primary radial bears upon each upper side four secondary radials which gives to this ray two arms. There are, therefore, eighteen arms in this species and eighteen ambulacral openings to the vault. There are three plates in each of three regular interradial areas, one large plate followed by two small ones. In the other area there are four plates, one large plate followed by two small ones in the second range and these by one in the third range. The azygous area is sub-ovate, in outline, and contains eight plates. The first is in line with the first primary radials and of about the same size. It is followed by three plates in the second range, and these by three plates in third range, above which, a single plate separates the first tertiary radials, while the second tertiary radials unite over its superior angle. The vault is about the same size as the calyx and very much like it in outline. It is covered with numerous, tumid, polygonal plates, each of which bears a central node. There are two pores that penetrate the vault between each pair of arms or eighteen of these so-called ovarian apertures in the species. 22 This species is distinguished, by its general form; by the beveled plates of the calyx; by the azygous area aud eighteen arms. There is no species with which it is necessary to make any comparison. Found in Keokuk Group, in Washington county, Indiana, and now in the collection of Wm. F. E. Gurley. ACTINOORINUS BOTRUOSUS, n. sp. Plate 2, Fig. 1, azygous side; Fig. 2, opposite side of the same specimen. Species robust, above medium size. Calyx nearly as long as wide. Radial series prominent aud inter-radial areas depressed so as to give it an ob,)yramidal form or sub-pentagonal outline to a transverse section. Plates tliick, tumid, and each one bears a cen- tral node, which, on the larger plates, is elongated transversely. The rays are abruptly expanded above the third primary radials, leaving the inter-radial areas depressed, thus forming projecting clusters of each of the five radial series and directing the ambulacral openings nearly horizontally. The sutures are interrupted by radiating sculptures, that are so short that the sutures appear as if pitted. Basals a little wider tliau high, very thick, contracted in the middle and at the upper part so as to leave an expanded rim projecting much beyond and below the point of attachment with the column aud having widely gaping sutures below so that the calyx will stand on the projecting aud contracted ends of the basal plates. Column round, radiately furrowed, and having a diameter a little more than one- third the greatest diameter of the expanded basals. First primary radials large, rather longer than wide, three hexagonal aud two heptagonal. Second primary radials wider than high, hexagonal, and more than half as large as the first. Third primary radials as large as the second, heptagonal, aud support- ing upon each of the superior sides a single secondary radial which is axillary, aud supports upon each of its superior sides two ter- tiary radials, the last of wlijch is axillary and supports the free arms, in all the rays that are preserved to show that extent of development in our specimen, tliough some of the rays do not preserve the first arm plates. If the arms are alike, therefore, in these four rays there are eight to each one. In the ray opposite the azygous area, on one side of the tiiird primary radial, there is a single secondary plate, which is axillary and supports on each upper side two tertiary radials, and on the other side there are 23 three secondary radials, beyond which our sp?cimen is not pre- served. If the last secondary and tertiary radials are axillary, there are six arms in this series. By this arrangement, if the arms are uniform, there are thirty-eight arms to this species. But, we cannot be certain that all the arms are double, as we know in some instances in other species such is not the case. The greater probability is, however, that they are uniform and that the species possesses thirty-eight arms. The ambulacral openings come to- gether on the first tertiary radial, and hence, if the projecting radial series were broken away, at this place, there would appear to be only nineteen ambulacral openings to 'the vault. There are no inter-secondary or inter- tertiary radials. The first regular interradiai is smaller than a second primary radial. It is followed by two smaller plates in the second range, and these by three smaller plates in the third range, which sepa- rate the lower part of the first secondary radials. Above this point there is some difference in the areas, and the plates are small and thrown out of any definite arrangement by being con- tinued up the sides of the projecting arm series as well as cov- ering the depressed interradiai area and graduating into the plates of the vault without any line separating the plates of the calyx from those of the vault. In one of the areas there are in the fourth irregular rang3 four plates and in another area there are five, these separate the first tertiary radials. Tlie fir^t plate in the azyzons area is .smaller than a first primary radial and in line with them. It is followed by two plates, in the second range, each of which is nearly as largo as a first regular interradiai, and these are followed by a range of three plates which are some- what smaller and separate the third primary radials. There are four plates in the fourth range and above this range the plates, in our specimen, are covered with the matrix so as to obscure the sutures, but the area above this does not seem to be differ- ent from the regular areas. The vault is convex and covered with large polygonal plates over the ambulacral areas, each one of which is jxjssessed of a large ventricose central node, while the interradiai areas are abruptly sunken and covered with small plane plates. The pro- boscis appears to have been quite small and central though broken away from our specimen. The ventricose vault plates in this species are much like they are in Aciinocrinus moniiculif- erns and the swelling may be due more or less to silicification. 24 This species is distiuguished by its general form and structure from all others that have been described and it does not seem that a comparison with any of them will aid in distinguishing it. Found by Prof. A. G. Wefherby, in the Keokuk Group of Ten- nessee, and "now in the collection of Wm. F. E. Gurley. 8ACC0CRINUS UMBROSUS, n. sp. Plciic II, Fig. 13, lateral vieiv, with azygous area on the right; Fig. 14, lateral view, witfi azygous area on ttic left, same specimen. Species large. Calyx urn-shaped below, but spreading at the top, so as to resemble a Strotocriniis, and which suggested the specific name. Only part of the spreading top is preserved in oar specimen, but enough to show it is much wider than the height of the calyx. Plates thick and tumid. Sutures deep and beveled. Surface ornamentation, if any, destroyed and also the plates of the vault in our specimen. Basals one-half wider than high, very thick, stand upright and form a hexagon two and a half times wider than the diameter of the column. The basals exieud below the point of attachment with the co'umu in the form of cuneate ends with widely gaping sutures below, so that the calyx will stand on the sharp and con- tracted edges of the basal plates. The calyx rapidly expands in rounded outline from the basals to the second primary radials. First primary radials large, of unequal size, width about one- fourth greater than the height, three hexagonal, two heptagonal. Second primary radials about one-third the size of the first, ([uadrangular and nearly square. Third primary radials a little larger than the second, three hexagonal, two pentagonal, axillary, and support on each upper sloping side one or more secondary radials, the last of which is axillary and supports tertiary radials, and in some of the rays, at least, there are quaternary radials. All of the rays in our specimen are injured at some point above the first secondary radials, so that no single ray can be com- pletely described. The first plate in each regular interradial area is large, and in the first area on the left, as shown by figure 13, there are only three plates, on(< following the other. In one of the other areas there appears to be only two, but this appearance may be due to an injury that exists above the second plate. In the azygous area there are nine plates, in subovate outline, that appear to fill thi.s area, but there is a large plate above these that does not '25 seem to belong to the radial series, and hence there is doubt about the area. The first plate is in line with the first primary radials and of about the same size. It is followed in tiie second range by three large plates, and these, in the third range, by three smaller plates, and above these there arc two still smaller plates that belong to this area. This species is so different from any other that has been de- scribed, in ■ the part preserved, that no comparison with any of them will throw any light upon it. Found in the Niagara Group at St. Paul, Indiana, and now in the collection uf Wm. F. E. (Turley. ERETMOCRINUS COMMENDABILIS, n. sp. I'Inle II, Fi(j. 15, a specimen showing part of eahj.r, arms anil column, nzygoiis area on ihe right. Species large. Calyx twice as wide as high, depressed iu the interradial areas and somewhat lobed in the superior part, broadly truncated below. Plates moderately convex and granular, sutures distict and more or less beveled. Column large and composed of thick plates that are beveled externally, and alternately project one beveled edge beyond the other. Columnar canal large and nearly round. Basals short, truncated below and expanded to a thin edge, irregularly hexagonal, in outline, and having a width twice the diameter of the column. First primary radials a little wider than high, three hexagonal and two heptagonal. Second primary radials short, more than twice as wide as high, quadrangular. Tiiird primary radials a little larger than Ihe second, pentagonal, axillary, and support on each superior sloping side two secondary radial.-. The secondary radials are larger than the second and third primrry radials, the second one is axillary and supports on each superior sloping side two tertiary radials. This arrangement gives to the species twenty arms. This is upon the assumption that the arm opposite the azygous area is like the three that are shown in the specimen, it being possible that it has only two arms. There are three single short plates in the commencement of each arm, these are followed by a double series of interlocking plates that are deeper than wide but which gradually widen, until at the distance of an inch and three-quarters from the calyx an arm is three times as wide as deep. In the only regular area shown in our specimen there are two plates, one quite large followed by another half its size. The first azygous plate is in line with th^ first primary radials and of —4 20 fibout (ho same size. It is followed by three laryc plates and above these there are either one or two plates, that extend to the top of the calyx aud connect with the plates of the vault. This species is distinguished by its general form, depressed in- terradial areas, lobed extention at the arm bases, by the plates of the azygous and regular areas, and otherwise. It is a typical Ki-ci- mocriiiKS and the question now arises whether or not it can be distinguished from Bahcrhius. The expanded basal plates is cer- tainly not a generic character in Aciinocrinus or Baiocrinus, it is not peculiar to Ercimocrinns. Can it be, that taken in connection with the coarse aud expanded arms, it becomes of generic value ? We think not. The column is larger than is usual in Baiocrinus, but that is certainly not a generic character. The form of the calyx and arrangement of the plates is the same as in Balocrimis. The only distinguishing difference left between Ereimocrinus and Baiocrinns is to be found in the expansion of the arms. We be- lieve that, in no instance, can this be of generic importance and, therefore, think that Ereimocrinus is separated from Baciocrinus by specific differences oidy. A mere combination of specific dif- ferences, which, if applied to its full extent, to Baiocrinus, would subdivide tlie genus into many genera. We have, however, i-e- tained the naipe Ercimocrimm, from deference to the opinion of others, and provisionally, because it may be a convenient division of Baiocrinus. Found in the Keokuk Group, at Crawfordsville, Indiana, and now in the collection of \Vm. F. E. Gurley. AGAKICOCRINUS I'ROFUXDUS, n. sp. ri((h' ■'!, Fiij. 1, Ixtsal i'icw: Fif/. 2, summit view; Fi(j. 3, azyrjous (•(>'«! of a suiallcr specimen. Sl)ecies large and ])reserving all the characters ascribed to it in numerous specimens. Calyx deep, hemispherical, outline snbpen- tagonal. Plates within the concavity below the third radials, plane and smooth, and tliose from the third radials outward very tumid. The abrupt change from plane to tiunid plates forms a rim within the concavity. ]>asals small and entirely hidden by the column. First primary radials large, length about e;]ualing the greatest width, a small part abruptly bent into tlie columnar concavity, three hexagonal two heptngonal. Secoiul primary radials large and nearly square. Third primary radials larger than the second and about as large as the first, very tumid, i^eutagonul, axillary, aud in three of the 27 rays support on each upper sloping side three secoudary radials, whicli gives to each of these raj's two arms. In each ray adjoin- ing the azygous area there is on each superior sloping side of the third primary radial a single secoudary radial, which is axillary and supports on each side three tertiary radials, whicii gives to each of these rays four arms. There are, tiierefore, fourteen arms in tliis species. The calyx is much more protuberant at the ends of the radial series adjoining the a/.ygous area than elsewhere, by reason of the increased number of radial plates. The arms are composed of a double series of siiort plates, from the commence- ment united by the usual zigzag suture. There is a single long twelve sided plate in each regular inter- radial area. It rests between the superior sloping sides of the first primary radials, where it is concave, to conform with the otliei- plates adjoining. It then curves over the summit of the calyx, where it is very tumid and separates the primary, secondary and tertiary radials and unites with two plates belonging to the vault. Tliere are four plates in the azygous area. The first one is in line with the first primary radials and slightly longer and narr<)W(!r than either of them. It is followed by three plates, the middle one of whiith is narrow within the concavity of the calyx, liut gradually expands a3 it curves over toward the vault and be- comes wider than the lateral plates at its union with the three plates belonging to the vault. The lateral plates are wide within the concavity of the calyx aud very tumid where they curve over toward the vault, but become narrow and flattened where they unite with the plates of the vault. The vault is highly convex, and interradial areas concave. There is a large, tumid plate at the apex of this vault, which is sur- I'ounded by sis large, convex plates aud from two to four small plates in the azygous area. In some of our specimens there are only two of these plates at the top of the azygous area, that sep- arate it from the summit plate, as siiown in figure 2, aud in others there are four, which is the case in the specimen illustrated by figure '•], but they are hidden from view, in the illustration, because of the prominence of the azygous swelling. A row of large tumid plates covers each ambulacral area from the summit to the arms aud there are two of these plates at the base of the arms in each of the four armed series. It would seem that the ambulacral canals are covered with large plates where they unite in each radial series. Tlie plates in the interradial areas are flattened or con- cave aud more or less elongated. The azygous area is very wide and beai's an elongated, more or less elliptical, bulbous promi- 28 neuce, in the upper part, which has an elongated azygous opening. The plates covering the azygous area and bulbous prominence are polygonal, variable in size, and fattened or concave. This species is distinguished from all others, heretofore describ- (d, by the character of the regular interradials and azygous plates, by the azygous area, and by having fourteen arms. After having examined several hundred specimens belonging to this genus, we believe that the number of arms do not vary within the proper limits of a species, and hence the number of arms may always be regarded as of specific importance. Other specific char- acters will always be found in the interradial and azygous plates, belonging to the calyx, but ditt'erences in the interradial plates belonging to the vault will be found in the same species. There is no increase in the number of plates belongiug to the calyx, with increase of size, in the same species; but there may be an increase, in the number of plates, in the vault, within the proper limits of a species. This maguificient species was found by Prof. A. G. Wetherby, in the Keokuk Group, in Tennessee, and is now in the collection of Wm. F. E. Gnrley. AGARICOCRINUS TUODRIDM, U. sp. Fhiif ITT, Fig. 4, hasal view, Fi(j. 5, snmmit view: Fiij. 6", azygous view of the same specimen. Species very large, subpentagonal in outline. Calyx broadly con- cave centrally and rounding up to the arms and having a fanciful resemblance to a hut, which suggested the specific name. The plates of the calyx are concave or flattened, and are in striking contrast with the tumid plates, in the species last described. Basals small and entirely hidden by the column. Fij'st primary radials wider than long, a small part abruptly bent into the columnar concavity, three hexagonal, two heptagonal. Second primary radials one-fouth wider than long, quadrangular. Third primary radials very large, even larger than the first, pentagonal, axillary and in three of the rays, support on each upper sloping- side three secondary radials, which gives to each of these three rays two arms. In each ray adjoining the azygous area, there is on one superior sloping side of the third primary ladial, three secondary radials, and, on the other, a single secondary radial, which is axillary, and supports on each upper side two tertiary radials, which gives to each of these rays three arms. There are, therefore, twelve arms in this species. The calyx is more protub- erant, at the ends of the radials adjoining the azygous area, than 29 elsewhere, ))y reason of the increased number of radial plates. The arms are composed of a double series of short plates, from the commencement, united by the usual /.igzag suture. There is s single, long, twelve sided plate, in each regular iuter- radial area. It rests between the superior sloping sides of the first primary radials, curves over the summit of the calyx sepa- rating the primary, secondary and tertiary radials, and unites with two plates belonging to the vault. There are four plates in the azygous area. The first one is, in the lower half, in line with the first primary i-adials, but it is more than twice as long as a pri- mary radial and curves over the calyx so as to be visible, in a side view, as shown in figure 6. It is followed by a sliort plate tiiat unites with two plates belonging to the vault. There is a plate, on each side of the first and second plate above described, that rests upon one superior sloping side of a first primary ra- tlial, is of about the same size as a regular interradial, has nine sides, and curves over and unites with two plates belonging to the vault. Each of these plates abuts one side against the primary, secondary and tertiary plates and the other against the first and second azygous plates. The vault is subpyramidal and flattened or slightly concave in the interradial areas. There is a very large, tumid plate at the apex of the vault, which is surrounded by si.x large, convex plates and one narrow elongated plate, in the azygous area. At least, there is only one plate at the top of the azygous area in the speci- men being ilescribed, which may be seen in figure '>. There is a single, very large, tumid plate over the lower part of three of the ambulacral areas, and two over th(^ lower part of the otiier two areas. These large plates cover the ambulacral canals, where they unite, in each radial series. All other plates in the vault are smaller than those described, but they vary much in size; some are convex, others flat, and others concave. Those in the inter- radial areas are not numerous and are generally elongated. The azygous area is almost wholly taken up with a remarkable bulb- ous, elliptical prominence that bears the azygous opening. The plates in this area are rather large, generally, and conform to the surface elevations and depressions. This spH^ies is distinguished from all others heretofore described by the characters of the regular interradials and azygous plates, by the azygous area and bulbous proarinence and by having twelve arms. Many other differences might be pointed out, but we deem these characters amply sufficient. We might begin to compare it witli Acidriforriiiiis profaniliiK, by saying that the calyx is pro- 30 portionall}' higher and the vault proportionally lower and so ou, but the species are so different from each other that they never, even in fragments, can be mistaken for each other, and no light would be thrown upon them by pursuing the comparison. And so it will be found by comparing it with any other defined species. Found by Prof. A. G. Wetherby, in the Keokuk Group, in Brown county, Kentucky, and now in the collection of Wm. ¥. K. (turley. AGAniCOCKINUS ARCUL.\, n. sp. I'I'ilc in, Fi(j. 7, hasal ricw of