﻿ANODONTA 383. 



g^ray and without luster; nacre bluish, sometimes reddish in 

 the center. 



IvCngth 50, height 41, diam. 2^ mm. 



Length 41, height 28. diam. 15.5 mm. 



J^ength 36.5, height 25, diam. 12 mm. 



Northwest Mexico ; Rio Ameca, State of Jalisco. 

 Anodonta richardsoni v^on Martens, Biol. Cent. Am., Moll.. 



1900, p. 529, pi. xLi, figs. I, la, 2, 2a. 



Seems to be rather closely related to A. e.vihor and A. coarc- 

 tata, but it has concentric wider and narrower ridges and the 

 epidermis is lusterless. 



Anodonta impura Say. 



"Subovate, fragile, a little compressed, dull yellowish-brown ; 

 umbo much eroded, exhibiting a chalky white stratum, then a 

 dull wax-yellow surface ; beak a little undulated, hardly ele- 

 vated above the general curvature ; hinge margin forming a 

 large angle with the base, being anteriorly elevated into an 

 obtuse angle, whence the edge descends almost rectilinearly 

 to the anterior margin, which is equally rounded with the pos- 

 terior margin. 



Length one inch and three-tenths, breadth less than two 

 inches. Convexity less than seven-tenths. Inhabits Mexico." 

 (Say). 

 Anodonta hnpura Say, N. H. Diss., H, 1829, p. 355. — Fischer 



and Crosse. Miss. Sci., H, 1894, p. 536. — von Martens, 



Biol. Cent. Am., Moll., 1900, p. 530. — Simpson, Syn., 1900, 



P- <'>35- 



? Anodonta cygnea impura Hannibal. Proc. Mai. Soc. Lon- 

 don, X, 1912, p. 125, pi. V, figs. I, 2, 7. 

 The types of this species have been lost and the form has 



never been definitely determined. In the Synopsis, I stated 



that "it is quite likely that it is the same as A. henryana." 

 Fischer and Crosse, (1. c), say, "from the dimensions and 



diagnosis, we believe that this species is related to A. coarctata 



Anton and A. exilior Lea." 



