CALYPTOCRINID.E. 359 



als, which are largely represented at the outer walls of the dorsal cup ; more- 

 over the orientation of the pentangular basal concavity is reversed, its angles 

 being directed interradially, while they are radial in C. cormdus and other 

 species. Dorsal cup nearly as high as wide, the base broadly truncated, its 

 lower margin a little projecting laterally and forming a sharp edge ; the 

 sides gently curving to near the top, where they slightly contract. The 

 suture lines are not shown in Roemer's type, but we can see from a fragmen- 

 tary specimen in our own collection that the basals are very irregular ; three 

 of them are quadrangular, the fourth pentangular and larger, the latter 

 broadly truncated and supporting a radial, which is smaller than the others 

 and slightly convex at the lower face. The other three basals, which rest 

 each one between two radials, are distinctly angular below. First costals 

 quadrangular, once and a half as wide as long ; the second considerably 

 larger and pentangular, the distichals arching over its upper angle. First 

 interbrachial large, decagonal, almost as wide as long. The plates thin, and, 

 so far as observed, without surface markings, except obscure angularities fol- 

 lowing the median lines of the radials and brachials, and a small conical 

 elevation within the middle of the first interbrachial. 



Horizon and LocaUtij. — Niagara group ; Wayne and Decatur Cos., Tenn. 



Type in the Mineralogical Museum, at Breslau, Germany. 



Remarks. — If this is a true CaUicrinus, it differs from all the other species 

 of this country, as well as of Europe, in the large size of its basals, which in 

 no other species are exposed along the sides of the cup. 



9 



