*H rafinesque's 



ribbed with a double epidermis, the outer rufous, the inner green- 

 ish : inside bluish purple. — Length '7-12, diameter 1-3, axis 1-4 of 



breadth. 



[3] 

 In Salt river, rare, small, l^ inch ; cardinal tooth almost as in 



Leptodea, lamellar tooth well curved, and flexuose. 



85 Sp. TJnio diaphanus, (Metaptera? diaphana 1821.) Shell 

 very thin, transparent, oval-elliptic, swelled, broader behind, with a 

 small wing, surface smooth horny, inside, pale incarnate. Length 

 3-4, diameter and axis 3-8 of the breadth. Var. lineolata with, ful- 

 vous greenish lines. 



In small streams of Kentucky, one or two inches, rare, cardinal 

 tooth compressed, crenulate, lamellar well curved. 



86 Sp. Unio lasmabrachys (Metaptera? do. 1820.) Shell 

 rather thick, oval triangular, swelled, truncate behind with an arched 

 ridge, surface rugose horny, inside bluish white, small truncate wing, 

 beaks prominent. Length 5-7, diameter 3-7, axis 2-7 of the 

 breadth. 



Licking river, &c., 3 or 4 inches, rare, deep cavity inside : teeth 

 ■wide apart, cardinal crenulate, lamellar very short, broad and trun- 

 cate in the right valve. This and the last belong more to Metaptera 

 by the teeth than the wings. 



,87 Sp. Unio rimosus, {Eurynia rimosa. 1823.) Shell elliptic, 

 thick, thinner, broader, and rimose behind ; surface olivaceous nearly 

 smooth, inside bluish white. Length 2-3, diameter 1-6, axis 1-4 of 

 length. 



In the Cumberland river, rare, small 1-^ inch. Resembling some 

 Amblemas, but evidently transversal, cardinal tooth crenulate, lam- 

 ellar smooth, short, nearly horizontal, but a little curved towards the 

 back. Perhaps a peculiar S. G. near to Epiohlasma, it might be 

 called Lemioos. 



88. Sp. Uniofulvus. (Eurynia fulva. — 1823.) Shell elliptical, 

 thick before, sloping behind, surface depressed nearly smooth, bright 

 fulvous or rufous outside and inside. Length one half, diameter and 

 axis one fifth of the breadth. 



Yar. 2. Fuscata, brownish rufous outside, pale inside. 



Var. 2. Bufa, quite rufous outside, iridescent inside. 



In Green river, Rockcastle river, &c., — ^rare, fine shell, 2 or 3 

 inches, cardinal tooth crenate, lamellar long and straight. Near to 

 my U. auratus. 



