ANODON.—P tate XXX. 
scurissimé biangulato, margine dorsali elevato, 
recto, cuneato, alato, 
Tne Urvevay Anopon. Shell short, ovate, thick in- 
flated, darkly olive, bluish-white within; anterior 
side very short, rather round, with dorsal margin 
depressed, ventral sloped upward; middle rounded, 
umboes rather elevated; posterior side expanded, 

very obscurely biangular, dorsal margin elevated, 
straight, cuneated, winged. 
Lea. Obs. on Unio, vol. x. p. 29, pl. 48, f. 302. 
Hab. Uruguay River, South America, 
It has not the obliquity of form which distinguishes 
Anodon latimarginatus, 

