REPORT OF THE DIRECTOR 1923 1 
Length about 11 mm; height 7.5 mm. 
Named after Dr Rudolf Ruedemann of the New York State 
Museum who recognized it as a new species. 
a vA 
Pterinea rotunda nov. 
f Plate 1, figure 6 
Shell small, length slightly greater than the height although the 
exact proportions are difficult to determine owing to the fragmen- 
tary nature of the material, the left valve only being known. Gen- 
eral form rounded, posterior wing prominent, anterior wing miss- 
ing on specimen. Huinge-line straight, about two-thirds length of 
shell. The beak is prominent and is the attenuate expression of 
the natural body rotundity. Radial markings faint, scarcely visible 
without the aid of a lens. Concentric growth lines. 
Length estimated about 21 mm; height 18 mm. 
¥ 4 ane 
*  Pterinea jordani nov. 
Plate 1, artis 8 
Shell moderately large with length and height about equal, hinge- 
line straight about three-fourths total length, form rounded as in 
P. rotunda nov. described above. Posterior wing broad prob- 
ably extending as far as the posterior margin of the shell. An- 
terior wing well defined but not sharply set off from the front 
margin, making a wide obtuse angle with the upper margin. Con- 
centric growth-lines covering the entire shell, best shown on wings. 
This species is the largest of the fauna and is known from 
poorly preserved left valves only. 
Approximate measurements are as follows: length 27 mm; 
height 28 mm. 
Named from the village of Jordan 2 miles west of the outcrop. 
Pterinea? sp. 
Plate 1, figure 7 
A pelecypod showing generic affinities with Pterinea was found. 
It exhibits plain concentric growth-lines and faint radial markings 
on the left valve, and the right valve shows evidences of ribs. 
Posterior wing plain, anterior poorly shown. 
Length 29 mm; height about 29 mm. 
