392 FOSSIL OSTEEID^ OF NORTH AMERICA. 



PLATE LXIII. 



OSTREA SELL^FORMis, Conrad. (Page 311.) 

 Fig. 1. — Under view of the example that is figured on Plate XXIX. 

 OsTKBA vicKSBURGENSis, Conrad. (Page ■312.) 

 2, 3. — Exterior and interior views of a lower valve ; natiir.il size. 



OSTRB A THIRST Gabb. (Page 311.) 

 4, 5, 6. — Exterior, lateral, and interior views of a lower valve ; natural size. 



i 



