UNIO REFLEXUS. 



Plate IV.— Fig. 1. 

 DESCRIPTION. 



Shell suboval, thick anteriorly; middle of the disks 

 with a single row of distant elevated tubercles, about 

 four in number; umbo not very prominent, subme- 

 dial; umbonial slope subcarinated; posterior side 

 slightly furrowed and emarginate at base; posterior 

 slope flattened, with transverse undulations; poste- 

 rior extremity truncated; within white; cardinal teeth 

 large, direct, much sulcated. 



Var. A. disks covered with small tubercles. 



Var. B. epidermis blackish, nacre purple. 



SYNONYMES. 



U. reflexus, Raf. Ann. gen. des Sc. Phys. vol. v. p. 40. 



Poulson's trans, p. 40. Say, Amer. Conch. No. 6. Ferussac, 



Mag. de Zool. 

 U. cornutus, Barnes. Silliman's Journ. vol. vi. p. 122. 

 Cab. A. N. S. No. 1750. 



OBSERVATIONS. 



Allied to the U. flexaosas, but approaches nearest 

 to U. gibbosus, Raf., yet may always be distinguish- 

 ed from that species by its suboval outline, and the 

 regularity and prominence of its tubercles. The 

 two varieties I found in the Alabama river. The 

 figure represents a tuberculated specimen. The 

 species preserves its distinctive characters in very 



