﻿3S6 ANOnONTA 



lions, which are generally somewhat doubly looped and oiien 

 slightly nodulous: ei)iderinis bright and shining, sonietni.es 

 faintly rayed. 



Animal having the branohia' large, inner larger in front, free 

 in part from the abdominal sac; marsupium occupying the en- 

 tire outer gills, forming an enormously thick, liver-colored 

 l)a(l when tilled; niantk' thin, thickened on its edge; branchial 

 papilla- small : anal opening smooth. 



Anouont.\ c.xtakacta Say. 



Shell ovate, long elliptical or rarely somewhat obovate, in- 

 flated, generally thin, inequilateral, witji a low post-dorsal 

 wing, scarcely truncate behind it ; beaks usually full and raised 

 above the dorsal outline, their sculpture consisting of several 

 corrugated ridges that have a tendency toward being doubly 

 looped ; posterior ridge moderately developed, generally feebly 

 biangulate : surface with irregular growth lines, which are 

 often develo]>ed into concentric ridges around the border of 

 the shell ; epidermis generally shining, greenish-yellow, yellow- 

 green or olive, usually banded with darker color and often 

 faintly rayed ; nacre l)luish-white. not shining, very rarely 

 thickened in front. 



Length. 135. height 70, diam. 50 mm. 



T^ower St. Lawrence drainage: streams draining into the 

 Atlantic south to North Carolina. This species has been cited 

 from Orand River. Michigan, and from north of Lake Supe- 

 rior. Mr. Uryant Walker states that the former locality is 

 erroneous, and T presume that the latter is. 



Type locality not given. 

 Anodonta cataracta Say, Nich. Enc, ist ed., IT. 1817. pi. iii. 



fig. 4. — D'ESHAvns, Tr. Elem.. L 1853. Pt. 2. p. 218, pi. xxx, 



fig. 4. — KusTF.R, Conch. Cab. Ano.. 1853. p. t,t,. pi. vii. fig. 2. 



— Simpson, Syn.. 1900, p. 631. 

 Unto cataracta Dfstiayks, Tr. Elem. Conch., 1830. p. t8. pi. 



xxx, fig. T. 

 Anodon cataracta C.\Ti.ow and Rkkvf.. Conch. Xom.. 184=;,. p. 



66. 

 Mytihn; cataractiis Eaton, Zool. Text-book. 1826. p. 224. 



