200 



the middle of the plate. First anal plate quadrangular, 

 nearly equal sided, resting upon two subradials, and sup- 

 porting on one upper side, one end of the adjacent first 

 radial plate ; second anal plate as large as the smaller first 

 radials, resting upon one subradial and the first anal, and 

 between the first radial plates of the adjacent rays. 



The subradials, first radials and anal plates are prominent 

 in the centre, with low angular ridges extending to the su- 

 tures, the intermediate spaces being depressed, giving a 

 strongly angular appearance to the cup. Entire surface 

 smooth or very finely granulose. Summit, arms, and column 

 unknown. 



The body of this species is usually somewhat unsym- 

 metrical from the anal side being more elongated or higher, 

 and less ventricose than the other sides. 



Geological formation and locality. — In shales of the age of 

 the Niagara group ; Waldron, Indiana. 



Cyathocrinus pusillus (Hall). 



Calyx small, forming a broad shallow cup, a little inflated 

 on the anal side. Basal plates very small, covered for 

 nearly one half their length by the column. Subradials 

 proportionally large, three hexagonal and two larger and 

 heptagonal. First radials short, broad, pentangular, the 

 width twice the height, the arm scar extending the entire 

 width and situated on the upper edge of the plate as in 

 Scaphiocrinics. First anal plate quadrangular, a little 

 longer than wide, resting obliquely upon the two hepta- 

 gonal subradials and supporting upon its upper side one 

 end of true adjoining first radial plate, the second anal 

 plate larger than the first, hexagonal, resting upon the top 

 of a subradial and against the upper end of the first anal, 

 supported on the sides by the first radial plates of the 

 postero-lateral rays. Summit and arms unknown, column 

 small, round at its junction with the body, entire surface 

 smooth. 



