58 CRETACEOUS GROUP 
entire specimen, nor, indeed, one sufficiently perfect to 
figure. It was found near Arneytown, New Jersey, by 
Mr. Conrad. 
oP. wenustusy (S.G. Myo Plow} fig. 7: 
Specific character. Orbicular, thin, depressed, with fifteen 
or twenty double costs, those on the lower valve delicately 
beaded. 
Diameter, about half an inch. 
Found with the preceding species. 
4. P. anatipes, (S.G. M.) PI. v. fig. 4. 
Specific character. Suborbicular, flattened, with four broad, 
convex ribs, longitudinally striated ; at the sides larger striz re- 
place the ribs. 
Diameter, more than half an inch. 
I have seen but one imperfect individual of this species, 
which is figured on the annexed. plate; it was obtained 
from a mass of Nummulite limestone, from Claiborne, 
Alabama. 
5. P. perplanus, (S.G.M.) PI. v, fig. 5, and pl. xv, 
fig. 8. 
Specific character. Orbicular, somewhat flattened, with about 
twenty small, simple costz, transversely striated. 
Diameter, from three-fourths of an inch to an inch and a 
quarter. 
Occurs with the preceding species. 
6. P. calvatus, (S. G. M.) PI. x, fig. 3. 
Specific character. Orbicular, depressed, smooth, thin, with 
a few obsolete radiating lines. 
Diameter three-fourths of an inch.. 

