NATURAL SCIENCES OF PHILADELPHIA. 151 



summit of first radial pieces, less than half the width. Base small, a little 

 concave below, or forming a nearly flat pentagonal disk ; basal pieces about 

 half hidden by the column the portion of each exposed pentagonal in form. 

 Subradial pieces much larger than the basal, four of them hexagonal, and one 

 on the anal side heptagonal ; each having a strongly elevated, bicarinate pro- 

 tuberance, extending out horizontally almost its entire length, like the rays 

 of a star, upon which the body rests when placed with the under side down. 

 First radial pieces two and a half to three times as wide as high, pentagonal, 

 and all transversely truncate their entire breadth above, for the reception of 

 the succeeding radials, so as to present a broad, moderately concave, outward 

 sloping facet above ; those of the two antero-lateral rays each nearly twice as 

 long as the others, and provided ne^r the middle of the upper margin with 

 two angular nodes or prominences ; sutures close fitting, and not very appa- 

 rent. First anal piece small, quadrangular, a little wider than high ; resting 

 upon the truncated upper side of one of the subradials, and connecting on 

 each side with a first radial, above which it does not project. 



Columnar facet of moderate size, a little concave, with a rather small, 

 rounded, central perforation, and traces of radiating striae around the margin. 

 Surface finely and regularly granulose. 



Height to summit of first radial pieces, 0-55 inch ; greater transverse diame- 

 ter, at summit of first radials, l - 04 inches. 



This species is evidently allied to C. sculptilis* of Hall, from the Burlington 

 limestone ; but it is much more robust, and has more prominent subradial 

 pieces, with the prominences more grooved along the middle. Its base is also 

 more concave, and its first radial pieces, particularly the anterior and postero- 

 lateral, proportionately shorter ; while it shows no tendency to develop ridges 

 across from the subradials to first radials, nor has it any surface striae. 



Locality and position. Warsaw, 111. Keokuk division of subcarboniferous 

 series. 



Cyathocrinus subtumidus, M. & W. 



Body below the summit of the first radial pieces, cup-shaped, robust, rather 

 deep, somewhat rounded below, with nearly vertical sides. Basal pieces well 

 developed, pentagonal, convex, about as wide as long. Subradials four or 

 five times as large as the basal pieces, thick, and very strongly convex, 

 slightly higher than wide, four hexagonal and one apparently heptagonal. 

 First radial plates about the size of the subradials, having a general pentago- 

 nal outline, with the two superior lateral angles usually a little truncated, 

 apparently by the first series of the vault pieces not tumid, like the plates 

 below ; each with a moderately concave outward-sloping facet for the recep- 

 tion of the next radial above. Succeeding primary radials (of which one 

 ray shows two, and another three,) about half as wide as the first radial 

 pieces, all rounded on the back, two in one ray, and one in another, trans- 

 versely oblong ; the last one in each of these rays proportionally a little 

 larger than the others, and supporting on its superior sloping sides the arms, 

 which, in the anterior ray, bifurcate again on the second piece. (Number and 

 arrangement of the anal pieces unknown.) 



Breadth of body, 0-90 inch ; height of body to summit of first radials, 0*72 

 inch. 



This species has the general aspect of Cyathocrinus bullatus and C. protube- 

 rans, Hall, (Iowa Report, 624 and 626, ) but differs from both in having its 



* We now regard our C.scilulus( Proceed. Acad. Nat. Sci., Phila., Sept., 1860, p. 393,) as a synonym 

 of C. sculptilis. Hall. Our description was going through the press when we first saw Prof. Hall's 

 Supplement to the Iowa Report, in which he described his C. sculptilis, and, owing to the necessa- 

 ry haste with which our comparisons hail to be made, and the fact that Prof. Hall had inadvert- 

 ently described oue of the subradi 1 pieces of his species as the first anal piece, and the first anal 

 as the second, caused us to overlook their probable identity. 



1865.] 



