L62 PALEONTOLOGY OF NEW YORK. 



the fossil was referred to the genus Echinocaris. This reference was evidently 

 based on the spinose character of the somites, but it is important to notice that no 

 species of this genus, of which the abdominal parts are known, possess spines of 

 similar character to those in this specimen. In Echinocaris punctata, E. socialis, 

 etc , these spines project over the posterior margins, their bases not being 

 conspicuously elongated. In this species, however, the longitudinal ridges, as 

 noticed in the description, do not extend heyond the posterior margins, the 

 spines being either produced by an internal thickening and a prolongation of 

 the portions of the test between the ridges, or were movable, detachable hodies, 

 having their bases articulated to the sides of the ridges, and directly compar- 

 able to the "epimeral" processes in the ahdomen of species of Stylonurus (e. g. 

 iS. Scoticus, Woodward, Palteontographical Society, 1872, pi. xxiii), and the 

 marginal abdominal spines in Limulus. In Stylonurus the dorsal surface of the 

 abdominal segments is often strongly ridged at their posterior margins as in 

 this species, but it does not appear to bear spines or the epimeral appendages. 

 It may be added that while this fragment would indicate a size for the entire 

 animal not great for a species of Stylonurus, it would be gigantic for Echinocaris, 

 upward of twenty-five inches in length if restored according to the proportions 

 of E. punctata. 



The true generic position of this species must remain a matter of uncer- 

 tainty until more light is thrown upon the question by the addition of new 

 material. 



Distribution. In the lower beds of the Portage sandstones, Italy, Yates 

 county. 



