ART. IX.-Description of Nine new species of Crinoidea from the Subcarboniferous Rocks of Indiana and Kentucky; by SIDNEY S. LYON and S. A. CASSEDAY.

PTEROTOCRINUS. Lyon and Casseday.

Asterocrinus, Lyon, Geol. Rep. Ky., vol. iii, p. 472.

SINCE our description of Asterocrinus was published in the 3d vol. of the Kentucky Report, we find the name to have been appropriated previously. We therefore propose Pterotocrinus as the name of our genus, which has now four well authenticated species,

Generic formula.

"2nd series, 10

Arms ciliated and single, 20

Wings or lobed pieces,

variously

5

formed.

Anal piece,

1 or more.

Pterotocrinus depressus, n. s.

Body, depressed, subconical, twice as wide as high; below the free arms it preseuts the form of a very shallow, flattened cup, the pieces composing it smooth and of equal thickness, in some cases nearly a plane, the margin curving suddenly upward at the junction of the arins; the vault rises from the arms at a very low angle, rapidly increasing towards the centre, where it is nearly perpendicular. Column-very small, formed near the body of circular pieces of unequal size and thickness. Basal pieces, two, similar in size and shape; not prominent. When joined, they together form an irregular pentagon, raised a little above the general surface of the cup; slightly indented at their junction with the column, which has one or more pieces buried in the pit in which it is attached.

Radial pieces of the first series, five; subquadrangular, similar in form and size, nearly twice as long as high. Radial pieces of the second series, ten, subquadrangular, differing slightly both in form and size, resting near the centre of the outer margin or the first radials, a little more than half covering them. The radials of the third series are twenty in number, differing slightly in size, subquadrangular, nearly twice as wide as high, ten of them resting upon the radials of the second series, the other ten resting partly on these and partly on the first radials. The radials of the third series support from four to five brachials of quadrangular form, four times as wide as high; from the summits of this last series the arins, which before had been horizontal, become quite erect, and are composed of a double row of pieces which join by angular sides in the center of the arms.

Anal piece, one; obtusely angular below, fitting into a depression of the basal pieces, rounding to a point above, rising above the first radials.

The vault is divided into five triangular spaces by the wings, five in number; each space is covered with seven pieces of a compressed hexagonal form, three rising from the arms from the first row; upon these rest two; in the angular space at the summit of these rests the sixth, similar in size to those below it; it is squarely truncated above, thus becoming pentangular; its upper margin supports a small quadrangular piece; there are some quite small pieces above this last, in our specimen, probably one row which may forin the mouth; between each of the five fields of the vault is a long lanceolate piece as wide as the other pieces of the vault, and about three times as long as those in the fields; the wings are attached to these long pieces by an articulating joint, and extend beyond the arms which embrace the vault, diminishing in thickness from their attachment outward, and terminating in a thin knife-like edge, equal in width to twice the height of the vault, the upper and lower margins nearly parallel; obtusely rounded at their outer extremity.

The arms are single, twenty in number, lying in sets of four between the wings, which, being placed immediately above the centre of the first radials, divide them into pairs, two from each of the adjacent radials falling into the spaces between each pair of wings. The arms are provided with a row of cilia for each side, formed of short joints, placed immediately in contact one above the other, filling the length of the arms which rise above the wings, about one sixth of their length. The dermal coating has been lost from all the specimens we have seen. The sides of the wings are strongly marked by a muscular attachment, by which they were moved. (?)

By reference to the figures it will be evident that this differs from all heretofore described species; by the bipartite basal pieces it is related to Dichocrinus.

Dimensions of Specimen of Medium Size.

Geological Position and Locality.—Several specimens have been found in the third intercalated limestone, of the Millstone grit, Grayson Springs, Grayson County. Same horizon, near Dr. Baker's furnace, Edmonson County, Ky.

Pterotocrinus pyramidalis, sp. nobis.

Body without the arms and winged appendages:-the vault is a pyramidal pentagon, nearly twice as high as the greatest diameter at its junction with the calyx. The calyx is vasiform, the rim of the vase slightly reflected downwards: four times as wide as high. Columnar pit deep, irregularly oval, the longest diameter transversely disposed with reference to the anal side. Columnar facet round, perforation not visible (in any specimen that has come under our observation).

Basal pieces, two; prominent, outer [margins thick and rounded, joined by a straight line to each other, the posterior margin having a deep angular notch, while the anterior side is but slightly indented at the

junction of the pieces; both pieces are irregularly pentagonal, nearly of the same form; that on the right of the anal piece being a little the largest.

First radial pieces, five; broad, sides diverging from below upwards, three times as wide as high, the ends of the upper margins parallel to the lower; about one-half of the length of the upper margin circularly depressed for the reception of two of the second radials to each.

Second radial pieces, ten; small, obscurely quadrangular, resting in the circular depression at the summit of the first radials, each pair being separated one from the other by a very minute anomalous piece, which rests on the center of the first radials between them; it is nearly round, and rises under the suture which marks the separation of the second radials, and is about one fourth the height of those pieces.

Third radials, twenty; small, differing both in size and form; nearly as high as wide, divided into five groups, disposed on a curved line, the exterior pair of each group resting partly on the first radial and partly against the oblique outer margins of the second radials. The central pair of all the groups rest upon the second radials, against those on either side and against each other. The articulating surfaces to which the arms were attached are slightly concave; the upper side deeply indented by a perforation into the body, partly in the arms and partly in the pieces immediately above them.

Anal piece, one; large, as compared with other species of this genus, long, hexagonal, obtusely pointed below, resting in the deep angular notch in the basal pieces; diminishing gradularly upward, supported on either side by the first radials; acutely pointed above, reflected toward the body, and supporting on either side one of the third radials.

Our specimens are weathered to such an extent that all surface markings (if they ever existed) have been removed.

Summit. The summit above the arms is divided into five fields, nearly of the same form and size, that above the anal side being a little the largest; they are covered by hexagonal or pentagonal pieces higher than wide. The largest field has four pieces in the first row, the other fields having only three each; the outside of each of the first series is articulated with a piece at the base of the wings, the second range and the superior margins of the third radials. Dividing the first range of pieces are five projecting angular pieces inserted between the groups of the first range, touching the third radials at one of its angular points, rising from them by a line slightly curved outward; they articulate with the first and second range of the five fields and with the wings, in the same manner as P. depressus (nobis). The second range consists of three long pentangular pieces, in the field above the anal piece, and two to each of the others. The third range consists of one lanceolate piece to each of the regular and two (?) to the irregular side. Between the fields of the summit is a broad articulating surface, about as wide as the pieces covering the fields, formed by the reflected margins of those pieces, and the supporting piece at the base of the wings. Wings-none have been found attached; great numbers are found loose, which we refer to this species. They are of various forms. The articulating surface applied to our specimen precisely fills and fits the articulating surface upon it; they are thick near the junction with the body, curved both above and below, gradually running to a point, five times as long as thick, broad on the upper surface,

gradually thinning downward; the outer end round and pointed; they are frequently found bifurcate near the end and double pointed: affixed to the specimen they radiate regularly and horizontally, the points being about as high as the summit of the specimen.

Mouth, central.

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Width Geological Position and Localities.-Found only in beds near the top of the third limestone of the Millstone grit series of Edmondson, Grayson and Breckinridge counties, Kentucky.

Fragments very abundant, good specimens rare. Beds from one to two feet thick are found composed of a mass of the remains of this crinoid cemented together, forming a distinctive and characteristic bed of the 3rd limestone.

Pterotocrinus rugosus, nobis.

The condition of our specimen is such that a particular description cannot be made the arrangement of the parts, however, is evidently quite similar to that of P. depressus. The basals, first, second and third radials, are present, together with parts of the wings and a portion of one of the arms. This species differs remarkably from P. depressus, in the greater thickness of the pieces, prominence of the base, the knobby protuberances upon it and upon the first radials, the depth of the columnar pit, as well as by its roughness and more robust appearance.

Geological Position and Locality.-A single crushed and imperfect specimen was found in the lowest siliceous mud bed,* at the Falls of Rough Creek, Breckinridge county, Ky. Fragments of this species are quite abundant.

The beds at Rough Creek, Grayson Springs, Grayson county, and Baker's Furnace, Edmondson county, are doubtless the equivalents of each other. In the western edge of Breckinridge county, they are separated by a thick sandstone, where the upper division of the limestone appears to be the equivalent of the beds above enumerated. The size and proportions of this species is about the same as P. depressus.

Zeacrinus ovalis, sp. nobis.

Body-When the arms are closed the body is ovoid, the length being equal to about twice the diameter; concave at the base.

Basal pieces, five; minute, forming a pentagon, slightly indented at the sutures marking the division of the pieces. When the column is present, the basals and about half of the subradials are concealed. Sub* Equivalent to limestone No. 3, Millstone grit.

radial pieces, five; four of which are of the same form and size; lanceolate, obtusely pointed at the superior extremity; the fifth is large, irregularly pentagonal; one of its sides supports two of the anal pieces. First radials, five; differing considerably in size; the anterior one being syinmetrical and the largest, the other four are unsymmetrical, the inferior side toward the anal field being longer than the inferior anterior side; they diminish regularly from the anterior to the posterior side. The second radials in all but the anterior ray are pentagonal, twice as wide as long, on the upper beveled sides of each supporting two arms. The second radial of the anterior ray is twice as wide as high, supporting on its upper side a third radial similar in size and form to the second radial of the other four rays, and like them it also supports a pair of arms. The arms are ten in number. The antero- and postero-lateral rays are composed of three quadrangular and one pentagonal piece each; one of the antero-lateral rays has the same form and number of pieces as the other and the anterior rays are composed of two quadrangular and one pentagonal piece each, somewhat larger than the pieces of the other rays. The inner upper margin of the last piece in all the rays support each one division of the ray, which is composed of about forty-five quadrangular pieces each, gradually diminishing in size to the end of this division of the ray, which is thus terminated in a point. The outer margins each support a branch which is bifurcated on the fourth, fifth or seventh piece, similar in form and arrangement to the first branch of the rays, the pieces being nearly as high and about half as wide as those below. The inner beveled upper margin of each last piece supports a branch which is of the same form as the inner branch below, composed of quadrangular pieces, terminating at the same height as the other branches. The outer margin of the second bifurcation of the anterior ray has in like manner an undivided branch of the same form and length; all the other rays are again bifurcated on the fifth or sixth piece, each division bearing two branches similar in form to the upper part of the inner divisions below; the anterior ray in its last division consisting of six fingers, all the others having eight fingers each, 46 fingers in all. The fingers are ciliated their entire length with a row on their inner margins.

Anal pieces, eight; the two inferior pieces rest partly on the subradials and partly against the first radials on either side, one rising nearly as high as the upper margin of the first radial against which it rests; upon these two rest two of the second range, and on the left side one quite minute, making the upper margin of the field nearly horizontal; the last two support one subquadrangular piece (the largest in the anal field) above which are three of the same form rapidly diminishing in size, thus running the anal field to a point.

Columns delicate pentagonal (near the body), composed of alternately larger and smaller thin pieces.