38 



radials. Surface fjranular. There are pits at the angles of the 

 larger plates m our specimen, but that character is not shown 

 on either of two casts and may not, therefoi-e, be normal. 

 One cast is one-fourth larger than the specimen illustrated. 

 It will be observed, that there is some difference, in the pro- 

 portional size of the plates, and the depressions on the cast, 

 this is because the internal sides of the plates are not like the 

 external surface. It is for this reason, that we cannot always 

 recognize the casts, when we arc conversant with specimens 

 having the ])lates well preserved, and it is, therefore, a mattei- 

 of gratification to be able to illustrate a species preserved iu 

 both ways. 



The basals form a small hexagonal, concave disc which is 

 almost wholly covered with the column. The first radials are 

 quite as long as wide and very slightly rounded from the 

 basals to the second radials, three hexagonal, two heptagonal. 

 Second radials quadrangular, about one and a half times as 

 wide as long. Third radials one-half larger than the second, 



, pentagonal, axillary and supporj; upon each upper sloping side 

 two secondai-y radials, the last of which are axillary and sup- 

 port the free arms. As near as can be asceitained, from our 

 sijecimens, there are four arms in each series, which arise 

 from the second secondary radials and are directed horizon- 

 tally. 



The interradial areas are wide and the plates connect with 

 those on the vault. In each i-egulai' area there are three plates, 

 one lai'ge followed by two elongated plates that unite with 

 thi-ee plates belonging to the vault. There are seven azygous 

 interradials, the first one heptagonal, in line with the first 

 primary radials and of the sauie size. It is followed by three 

 plates in the .second i-ange and thi'ee in the third range, which 

 unite with four plates belonging to the vault. The vault is 

 convex, and bears a subcentral azygous prominence, with the 

 orifice on top, but whether or not thei-e is a proboscis cannot 

 be determined definitely from our .specimens. 



This species would be classed with S{eganoc7-inus if it had 



: hexagonal, second, primary radials. But, aside from llic un- 

 usual, flattened, pentagonal outline, the calyx is that of a true 

 Bdiocrinus. There is no si)ecics described in either genus, 



, -witli which it is necessary to compare it. 



