PALAEONTOLOGY OP IOWA. 679 



Scapliiocriims decabrachiatus ( n. s.). 



PLATE XXV. FiG.l. 



BODY and arms subcylindrical, tapering to the base. Basal 

 plates small, forming together a very shallow basin : sub- 

 radial plates about as wide as long. First radial plates a little 

 wider than long. Second radials nearly once and a half as long 

 as wide, distinctly concave at the sides ; the upper sloping 

 faces supporting a pair of arms which are composed of sub- 

 cuneate plates in alternate series, the lower ones of which 

 are conspicuous and concave on their longer sides. Arms 

 simple from their origin, and tentaculate from the upper 

 angles of the longer sides of the plates. . 



This species, in its simple arms, resembles the iS 1 . simplex of the Burlington lime- 

 stone; but the body is proportionally much longer, the basal plates larger and more 

 prominent, the anal plates conspicuously different in form and arrangement, and the 

 plates of the arms longer. 



Fig. 1. The anal side of specimen; the right antero-lateral ray somewhat broken and 

 distorted. 



FIG. 106. 



The accompanying diagram illustrates the form 

 and proportions of the plates of the body and bases 

 of the arms. 



Geological position and locality. In the Kaskaskia limestone : Kaskaskia, 

 Illinois. 



Scaphiocrinus internodius ( n. s.). 



PLATE XXV. FIG. 2. 



CALYX symmetrically turbinate to the top of the first 

 radials. Basal plates proportionally large, as long or longer 

 than wide : subradials, except on the anal side, symmetrical- 

 ly hexagonal, as wide as long. First radial plates pentagonal, 



