64 
BULLETIN OF THE LABORATORIES 
Schizodus neivarhensis, sp. n. 
(Plate X, Fig. 1 ) 
Shell large, obliquely ovate, produced. Beak prominent, not 
projecting much beyond the hinge. Surface quite convex in the um- 
bonal region, becoming flattened posteriorly. Lower margin a gentle 
curve, very oblique to the axis, anterior margin strongly convex, posterior 
margin a gentle curve meeting the lower line acutely. The [)OSt-umbonal 
region expanded, flat ; anterior umbonal slope rather abrupt. Beaks an- 
terior; surface marked by fine regular striae. Our single specimen is 
very remarkable for the strong curvature of the surface below, opposite 
the beaks and flatness of the posterior ear. This may be due to oblique 
pressure as the opposite valve is crushed and displaced. Notwith- 
standing this the ovate form, large size and position serve to distin- 
guish it. Length 62 mm; height 50 mm; convexity of both valves 
about 23 mm. Collection of W. F. Cooper. Highest layers i mile 
north of Newark. 
Schizodus cheinun^ensis, var? aequalis, 
(Plate I, Fig. 25. ) 
Shell of rather large size, moderately convex ; beaks projecting, 
rather high; length slightly greather than the height ; form subquad- 
rate, produced at the lower posterior angle ; lower mat gin nearly uni- 
formly convex, with a slight sinus in front of the posterior angle; pos- 
terior margin nearly straight and nearly parallel to the longitudinal 
axis of the shell; anterior margin strongly curved; anterior umbonal 
ridge rather inconspicuous, post-umbonal ridge prominent, in front of 
it a rather deep groove extending from the sinus of the margin to- 
ward the beak; post-umbonal slope rather steep, concave. Surface 
marked by numerous fine concentric striae and coarser ridges. The 
right valve is most convex in our specimens. Height 42 mm; length 
48 mm ; (height 38 mm ; length 42 mm.) 
Freestone of middle Waverly at Granville, and 6 miles northwest. 
Collected by W. F. Cooper and C. L. Herrick. 
We are convinced that the attempt to specifically discriminate the 
