57 



epidermis dark green-olive, wrinkled; wrinkles lamel- 

 liform posteriorly; within reddish-purple, iridescent; 

 cardinal teeth direct, double in each valve; lateral 

 teeth arcuate. 



SYNONYMES. 



U. alatus, Say. Nich. Enc. , Am. ed., art. Conch. 



U. (metaptera) megaptera, Raf. Ann. gen. des Sc.Phys., vol. 



v. p. 299. 

 Symphynota alata, Lea. Trans. Amer. Phil. Soc, (new series,) 



vol. iii. p. 448. 

 Cab. A. N. S. No. 20409. 



OBSERVATIONS. 



This well known species approaches a variety of 

 U. purpiiratus, Lam., but is less inflated and has a 

 more elevated wing. From the fragilis it can be 

 distinguished by its larger size, dark epidermis, purple 

 nacre, thicker cardinal teeth, &c. 



Inhabits Fox and Ouisconsin rivers, North- West 

 Territory, Mr. Barnes; Detroit river, Michigan, Dr. 

 Sager; western streams generally, and the great lakes. 

 It is extremely rare in South Alabama. 



UNIO INFLATUS. 



Plate XXXII. 



DESCRIPTION. 



Shell triangular, ovate, thin; contracted obliquely 

 from beak to base; inflated over the umbonial slope; 

 valves elevated into a small wing anteriorly and into 



H 



