NATURAL SCIENCES OF PHILADELPHIA. 393 



The anal piece is small, apparently pentagonal, and projects distinctly above 

 the summit of the first radials, with which it connects on each side. Instead 

 of resting directly upon the upper side of one of the subradials, it is supported 

 on the upper slightly oblique truncated extremity of a very large pentagonal 

 subanal piece, which rests upon the upper sloping sides of two subradial 

 pieces, and supports the inferior sloping edge of a first radial plate on each of 

 its oblique lateral margins. 



Height from the base to the top of the first radial pieces, 0-45 inch ; breadth, 

 0'90 inch ; breadth of base, 0-23 inch ; length of subradials, 0-36 inch ; breadth 

 of do. from 0-36 to 0-40 inch ; leDgth of first radials, from 0-28 to 0-30 inch ; 

 breadth of do. from 0-35 to 0-49 inch. 



This, and the last species, together with such forms of C. spurious, C. inter- 

 medius, and C. ? pentalobus, Hall, should probably form a subgenus, bearing 

 close relations both to Poteriocrinus and Cyathocrinus. 



Locality and position. Ovan, Fulton county, Illinois. Lower Coal Measures. 



Cyathocrinus scitolus. Body below the summit of the first radial plates 

 basin-shaped, about twice as wide as high, and truncated at the base, from 

 which it expands rapidly upward ; composed of thick, strong, subgranular 

 plates, which are very convex in the middle, and deeply excavated at the 

 corners ; sutures moderately distinct. Base small, flat or truncate, on a plane 

 with the prominent portion of the subradials, so as not to be seen in a side 

 view ; columnar facet a little concave, occupying about two-thirds the area of 

 the base, and perforated by a central opening equal to one-third its own 

 diameter. Subradial pieces about as wide as long, directed obliquely outward 

 and upward from the base; four of them pentagonal and one hexagonal, there 

 being no visible angle at the middle of the under side in any of them. First 

 radials much larger than the subradial pieces, about twice as wide as high, 

 unequal, two on the anal side being shorter than the others ; all pentagonal, 

 distinctly truncate, and a little concave above, the upper side being much 

 longer than either of the others ; superior angles also slightly truncated for the 

 reception of small interradials. Anal piece small, subquadrangular, widening 

 from the base upwards, and projecting above the first radials. 



The very prominent central portions of the subradial pieces are truncated 

 below on a plane with the base, and project out horizontally from it in such 

 a manner as to form with the base a distinct five-rayed star, as seen from 

 below. From near the middle of each subradial, there is a rather obscure 

 angular ridge extending along each side of its prominent central portion to the 

 basal pieces, and another connecting with a similar ridge near the edge of each 

 first radial plate above. From the obliqueness of the upper truncated side of 

 the first radial pieces, it is manifest that the other radials must have extended 

 very obliquely outward from them. 



Height to summit of first radials, 0-32 inch ; breadth 0-66 inch ; breadth of 

 base 0-21 inch ; length of subradials, 0-21 inch; length of largest first radial 

 pieces, 0-20 inch ; breadth of do. 0-36. 



Locality and position. Burlington, Iowa. Burlington Limestone of subcar- 

 boniferous series. 



Cyathocrinus angulatus. Body of medium size, somewhat basin-shaped 

 below the arms, wider than high, truncated below, and rapidly expanding 

 upwards; composed of very thick, nearly smooth, tumid, angular plates, which 

 are united by distinct sutures. Base small, and apparently projecting a little 

 below the base of the subradials. Subradial plates as wide as high, four of 

 them pentagonal, and one on the anal side hexagonal, there being no visible 

 ano-le in the middle of any of them below. First radials larger than the sub- 

 radial pieces, about twice as wide as long, pentagonal, or subheptagonal, the 

 upper angles being sometimes slightly truncated ; all broadly truncate, and a 

 little concave above. Second radial pieces extremely short, but differing 



I860.] 27 



