306 Neiv Species of Crinoidea from the 



GENUS SCAPHIOCRINUS. 



Scaphiocrinns spinohrachiatus ( n. s. ). Body small, 

 broadly calyculate. Basal plates small, pentagonal, point- 

 ed above, extending laterally from the column, with the 

 outer ends curved abruptly upwards. Sub-radial plates 

 of moderate size, length and breadth about equal. First 

 radial plates comparatively large, twice as wide as high, 

 lateral margins short, the upper face slightly concave. 

 Second radial plates short, broad, strongly pointed above, 

 constricted in the middle, supporting on the upper edges 

 the first arm plates, which are much stronger than the 

 succeeding ones. Anal plates unknown. 



Arms two from each ray, very long, simple, composed 

 of a single series of short plates alternately longer and 

 shorter on their opposite edges, ornamented on the longest 

 side by one or two strong, elevated nodes or sub-spines. 

 Surface of calyx plates moderately convex ; the sub-radials 

 more elevated than the others, marked by a series of ab- 

 rupt depressions at the junction of the angles of the adja- 

 cent plates, as if the angle of each one were excavated. 



In the specimen described the arms are preserved to the 

 length of about three inches, and are still imperfect and 

 scarcely less in size than at their base. 



This species is distinguished from others by the spinous 

 structure of the arm plates. 



Geological formation and locality. Burlington lime- 

 stone, Burlington, Iowa. Collection of C. A. Wliite. 



Scaphiocrinus Wliitci (n. s.). Cup very small, symmet- 

 rically turbinate from the column to the top of the first 

 radial plates. Basal plates minute, strongly angular, point- 

 ed at the top. Sub-radial plates small, four hexagonal and 

 one heptagonal, a little higher than wide. First radial 

 plates of moderate size, iiTegularly pentagonal, strongly 

 angular below, upper margin straight, extending the full 



