61 



Var. 2. mridis epidermis of a fine olive 



green colour. 



Var. 3. violacina nacre violaceous. 

 Var. 4. nigrescens blackish olive. 



Very common in the Ohio, and all the adjacent 

 rivers. Breadth from two to four inches ; the 

 lamellar wrinkles are wholly separated from the 

 edges of the shell ; the posterior wing is com- 

 pressed, angular, sloping and brownish. It might 

 perhaps have been proper to name this species 

 A. mutabilis. 



SPECIES LIX. Anodonta lata (Lastena lata.) 



Shell very thin, fragile, translucent, convex, 

 oblong-elliptical ; apices decorticated, almost in- 

 visible ; epidermis brown, blackish anteriorly ; 

 nacre bluish, violet under the apices. Length f 

 diam. f axis of the breadth. 



Found in the Kentucky, &c. rare ; breadth 

 from two to three inches ; lamellar wrinkles at 

 the anterior edge, scarcely apparent. This spe- 

 cies ought perhaps to form another sub-genus 

 Hemistena, or be united to the first sub-genus, 

 but that the ligament is double or extended from 

 the two sides of the apices. The Lastence ap- 

 proach the genus Dipsas, [of LEACH.] 

 6* 



