101 



the least declining; posterior margin very oblique, 

 rectilinear; extremity obtusely rounded, considerably 

 above the line of the base; beaks decorticated, 

 slightly prominent; umbonial slope rounded; epider- 

 mis very dark olivaceous, wrinkled; within chocolate 

 purple; cardinal teeth oblique, single in one valve and 

 double in the other; cavity of the umbo and posterior 

 side very capacious. 



OBSERVATIONS. 



A small species found by Dr. William Blanding in 

 the Wateree river, South Carolina. It resembles the 

 U. parvus, but differs in having a much less wrinkled 

 epidermis, and inflated umbonial slope, more obtuse 

 posterior extremity, but more obviously in the dark 

 purple colour of the interior. Since the figure was 

 drawn, I have seen a larger specimen in the cabinet 

 of Mr. Vanuxem, from the Warm Springs of North 

 Carolina. It is less inflated and more regularly 

 elliptical than the Wateree shell. 



UNIO MELINUS. 



Plate LV.— Fig. 1. 

 DESCRIPTION. 



Shell oval, slightly ventricose, moderately thick, 

 slightly contracted from beak to base; beaks promi- 

 nent, with fine crowded undulations; ligament margin 

 elevated, not oblique; posterior margin oblique, ex- 

 tremity obtusely rounded; umbonial slope rounded; 



