compressed, and having a different aspect. It is found in 

 ponds, near the Wabash river, but rarely if ever, in the 

 river itself, as it prefers still water and a muddy bottom. 

 In form it approaches nearer to orbicular, than any other 

 species that we have seen described. 



An American conchologist was of the opinion that all 

 our Anodontas are referrible to one species ; but we con- 

 ceive that the present species, cannot with more propriety 

 be united with the cataracta and marginata, Nob., not to 

 mention the more elongated species, than the various spe- 

 cies of Unio can be considered as no other than V.picta, L. 



REFERENCE TO THE PLATE. 



Upper figure is the inner view. 

 Middle figure — exterior view. 

 Lower figure — dorsal view. 

 PLATE XI. 



