THE FOSSIL REPTILES OF NEW JERSEY. 89 
O. chelydrinus presented sharp points round the circumfer- 
ence, like a snapping tortoise. O. emarginatus had open 
notehes between, at the same parts of the margin, and O. 
platylomus was even. O. emarginatus was the giant of all 
the snappers and probably commonly reached a length of six 
feet. An ally, the Zuclastes platyops, whose cranium has 
been found, presented a broad, massive palatal surface, 
apparently for crushing, rather than the sharp edges and 
hooked bill of the raptorial snapper. It may have crushed 
shells for food. The Lytoloma angusta Cope shows a similar 
type of jaws. In the Euclastes, the skull measures about a 
foot in length, and eight inches in width, and accommodated 
immense temporal muscles, which indicate the power of its 
bite. 
More elegance and less strength characterize the Hydra- 
spid species. Five of these have been described, as follows: 
Bothremys Cookii Leidy; Prochonias sulcatus Leidy sp.; 
P. strenuus Cope; P. princeps Cope, and Taphrosphys mo- 
lops Cope. 
In the first we have a well protected cranium with small 
eyes, with the Milesian traits of a broad mouth, a pug-nose, 
and a stiff upper lip. His form seems to combine the capaci- 
ties of doing as much injury to others and receiving as little 
himself as possible. What his shell was we do not know, 
but we know that he could not draw his head into it, by rea- 
son of a peculiar structure on the sides of his inner nostril. 
Of the other genera, the numerous shell fragments tell a 
similar story. It is only necessary to see whether the pelvis 
was attached to the lower shell, or plastron, to know whether . 
the cervical vertebre would form a sigmoid, and be with- 
drawn into the shell, or a horizontal curve and turn round 
outside, as a goose rests its head above its wing. Or, if 
the front part of the plastron only be found, if there be a 
supplemental plate in the front, we know both the flexure of 
the neck, the arrangement of the pelvis, and the structure 
of the nose. TEG is a result of the law of correlation, 
AMER. NATURALIST, VOL. HI. 


