162 
PALEONTOLOGY OF NEW YORK. 
the fossil was referred to the genus Echmocaris. This reference was evidently 
based on the spinose cliaracter 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 beyond 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 bodies, 
having their bases articulated to the sides of the ridges, and directly compar¬ 
able to the “ epimeral ” processes in the abdomen of species of Stylonurus (e. g. 
8. Scoticus, Woodward, Palaeontographical 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. 
