482 GEOLOGY OF OHIO. 



FOSSILS FROM THE COAL MEASURES. 



ECHINODERMATA. 



CRINOIDEA. 



Genus CYATHOCRINUS Miller. 



Cyathocrinus Somersi 



Plate XI, figs. 4 and 5. 



Cyathocrinus Somersi Whitf., Ann. N. Y. Acad. Sci., 1882, p. 226. 



Calyx very shallow, being low and spreading ; the extreme height to the top 

 of the first radial plates not exceeding one-fourth of the diameter ; the sides, above 

 the middle of the subradial plates, gradually and almost evenly curving. Centre 

 of the calyx below deeply impressed, the cavity embracing the basal and inner half 

 of the cubradial plates. Basal plates very small, extending but little beyond the 

 circumference of the proportionally small column, and forming b}- their union a 

 somewhat regular pentagon. Subradial plates of medium size, four of them being 

 equal, and pointed at their upper ends, the upper edges being convex; the fifth 

 plate is larger than the others, and is truncated above by the very small first anal 

 plate, which rests between the adjacent first radials, and has apparently joined three 

 other plates above. The surface of this plate bears a single round granulose tuber- 

 cle. First radial plates nearly twice as wide as high; their lateral faces being short 

 and uniting with those of the adjacent plate, except on the anal side, where they 

 are separated by the first anal plate. Articulating face for the second radials 

 nearly straight, but deeply grooved. Second radial plates short; that of the an- 

 terior raj' being cuneiform above, and has supported an arm-plate on each upper 

 sloping surface. The second radials of the other rays have not been fully deter- 

 mined; but on the antero-lateral rays, where partially detached plates remain, they 

 have been quadrangular, as if for the support of other radial plates in a direct 

 series. Surface of the inner half of the subradial plates smooth, while the outer 

 half and the entire surface of the other plates are covered with proportionally 

 large, distinct, irregular tubercles, which are flattened on their surfaces and covered 

 with numerous small, distinct granules. The granules also extend to parts of the 

 intermediate surface. The upper margin of the first radial is bounded by an ele- 

 vated transverse ridge, which is also granulose. 



This species bears considerable resemblance in its general surface- 

 markings to Eupachycrinus tiiberctdatus M. and W. (Geol. Sun*. 111., vol. 

 v, pi. 24, figs, a, b), but the tubercles are very distinctly granulose. It, 

 however, does not possess the structure of Eupachycrinus, having only 

 one small anal plate, the upper end of which projects above the line of 

 the first radials. The only specimen yet obtained of the species measures 

 about three-fourths of an inch in diameter, and is about three-sixteenths 

 of an inch high to the top of the first radial plates. 



Formation and Locality. — In the Coal Measures at Carbon Hill, 

 Hocking county, Ohio. Collected b}- Mr. Somers, of Columbus, Ohio. 



