92 
PALEONTOLOGY OF NEW YORK. 
Pterinea pinguis. 
PLATE XV, FIGS. 2, 3; and PLATE LXXXIII, FIG. 13. 
Pterinea pinguis, Hall. Pal. N. Y, vol. v, pt. 1. Plates and Explanations: PI. 15, figs. 2, 3. Jan., 1883. 
Shell large; gibbous, obliquely ovate, length and height nearly equal. Pallial 
margins rounded, produced on the posterior basal side, and concave at the 
junction of the wings. 
Left valve ventricose, sub-angular along the anterior side. Right valve 
unknown. 
Hinge-line straight, nearly central; length somewhat greater than the 
length of the shell. 
Beak acute, angular, arching over the hinge, situated near the anterior 
extremity of the hinge-line, directed forwards. Umbonal region prominent, 
ventricose, defined, subtending an acute angle. 
Wing large, triangular, limited by the rapid post-cardinal slope of the 
valve; margin slightly concave, rounding to the extremity which is angular. 
The extent of the ear is not known, but it is limited by a deep sulcus which 
gives an angular aspect to the antero-cardinal slope of the shell. Byssal 
sinus not marked in the specimens. 
Surface ornamented with about fifteen broad, strong, rounded rays, crossed 
by lamellae of growth. The specimens described are weathered casts of the 
interior and preserve only slight evidence of the surface characters. 
Interior not known. 
The largest specimen has a convexity of about 20 mm., its length 70 mm., 
height 65 mm., hinge-line more than 65 mm. Another example has a con¬ 
vexity of about 20 mm., length 63 mm., height 74 mm., hinge-line 55 mm. 
This species bears some general resemblance to P. flabella; it differs in its 
large ventricose form, more elevated umbo, the characteristics of the upper part 
of the anterior side of the body, and the abrupt slope into the wing without a 
distinct sulcus. 
Formation and locality. In the Corniferous limestone, near Columbus, Ohio. 
