329 Bulletin 5 59 



FOSSIL SHELLS. 153 



Length of the larger valve hardl}^ more than 

 the fourth of an inch, breadth more than two-fifths 

 of an inch. 



A very pretty species. It was imbedded in a 

 mass which contained fragments of the large Perna. 



2. C. incequale. PI. xiii. fig. 3. Shell convex, 

 transversely ovate-trigonal, rough, with unequal 

 coarse wrinkles : anterior margin with a very acute 

 but short rostrum at its inferior termination, sepa- 

 rated from the disk by an acute line : base rounded 

 and a little contracted near the anterior angle : 

 umbones not prominent. 



Length two-fifths, breadth rather more than half 

 an inch. 



This species has a different aspect from the 

 preceding ; it is longer in proportion to its width, 

 more convex, and the wrinkles, though prominent, 

 are altogether destitute of that equality which dis- 

 tinguishes those of the other shell. 



PANOP^A, Menard. 



P. reflexa. PI. xiii. fig. 4. Exterior and interior 

 views. Shell transversely oblong-subovate : ante- 

 rior margin somewhat narrower and longer than 

 the posterior margin, the edge reflected : surface 

 wrinkled, and profoudly so towards the base. 



Length three inches and two-fifths, breadth five 

 inches and seven-tenths. 



This fine shell approaches closely to the P. fau- 



VOL. IV. — NOVEMBER, 1824. 20 



[J. A. N. S., Phila., ist Ser., VoL IV, 1824.] 



