Description of Ten New Species of Fossils. 



81 



the long strong arms and coarse pinnules, and more especially, from 

 all others heretofore described, by the fact that it has only ten arms. 

 It is a true Glyptocrinus, however, and as four specimens have been 

 collected, we can safely conclude, from all the appearances, that they 

 are mature, and that the species never possessed more then ten arms. 



It was collected by Wm. J. Patterson Esq., in rocks of the age of the 

 Utica Slate, in the banks of the Ohio river, opposite to the city of 

 Cincinnati. 



Saccocrincs piriformis, n. sp. 



Plate III., fig. 3, side view of a slightly compressed specimen, but showing the vault too 



much elevated : fig. 3<7, summit view. 



Body usually rather large, sometimes having a length of 2^ inches, 

 and a breadth, at the summit, of If inches. It gradually expands from 

 a subacute base to the arms, vault very moderately convex. 



Basal plates wider than high, hexagonal, and about half the size of 

 the first primary radiate. 



Primary radiate. — Three of the first radials rest upon the wider 

 sides of the basals, and two in the angles formed at the junction of 

 the basals. Three are hexagonal, and two heptagonal. Height and 

 width subequal. Second radials smaller than the first, hexagonal, and 

 a little higher than wide. Third radials smaller than the second, and 

 very regularly heptagonal. 



Secondary radials. — The first secondary radials are heptagonal, and 

 from half to two thirds as large as the third primary radials. The 

 second secondary radials are heptagonal, and smaller than the first. 



Tertiary radials or brachial series. — There are three tertiary radials 

 or brachial plates in each series. 



Interradials. — The first regular interraclials are hexagonal, a little 

 smaller than the first radials, and about as high as wide. These are 

 succeeded by five pairs or ten plates before reaching the interbrachial 

 spaces, and these are followed by three pairs of small plates in the 

 interbrachial spaces before reaching the top of the vault. There are* 

 five intersecondaiy radials, succeeded by interbrachials. Vault 

 moderately convex, with a convex ridge extending from the central 

 part over the azvgous side. Arras twent\\ 



Remarks. — This species is distinguished from S. urniformis with 

 which it seems to be most nearly related, by the more gradual ex- 

 pansion of the body from the base upward, and more regularity in the 

 size of the plates, by the absence of a third plate intervening between 



