THE NAUTILUS. 



115 



Strepomatid^. 



Goniobasis virginica Gmel. 



CORBICULID^. 



Sphaerium transversiim Say. 

 Sphaerimn striatinum Lam. 

 Pisidium virginicum Gmel. 



Unionid^. 



Unio complanatus Sol. 

 TJnio cariosus Say. 

 Unio nasuUis Say. 

 Anodonta Tryonii Lea. 



