292 New Species of Crinoidea from the 



GENUS CYATHOCRINUS. 



Cyathocrimts latus (n. s.). Calyx very broadly cyathi- 

 form, the width more than twice the height to the top of 

 the first radial plates. Basal plates proportionally small, 

 forming a nearly regular pentagon, the faces of which are 

 slightly indented at the suture lines, covered by the sum- 

 mit of the column, except the salient angles. Sub-radial 

 plates of medium size, wider than high, protuberant, three 

 hexagonal and two heptagonal, one of these being the 

 largest and the other the smallest of the series. First ra- 

 dial plates large, twice as wide as high ; those of the 

 postero-lateral rays a little shorter than the others, and 

 proportionally wider; the upper articulating face very 

 large, occupying more than three fourths the width of the 

 plate. 



The principal anal plate is large, quadrangular, resting 

 on the truncated summit of a sub-radial plate ; on the right 

 side is a small quadrangular plate intercalated betv/een 

 the sub-radial plate on the longer lower side and the first 

 radial plate, while the shorter sides rest against the large 

 anal plate and the sub-radial on the right. Structure 

 above the first radials unknown. Surface of plates of the 

 upper part of the body strongly corrugated ; the lower part 

 of the sub-radial plates less strongly marked ; this feature 

 is subject to much variation from weathering, and some- 

 times appears as undulating rugose striae. The sub-radial 

 plates are very convex, and rendered protuberant by the 

 thickening in the middle, while at the angles they are de- 

 pressed and thinner. The rugose striae of the radial plates 

 radiate from near the upjier margin, and are directed to 

 the lateral and lower margins, meeting similar striae from 

 the sub-radial plates. 



This species resembles C. tumidus and C. bullatus of the 

 Keokuk limestone, and, in the protuberance of the sub- 



