﻿NEPHRONAIAS 27 1 



IJriio aztccorttm var. chapalanus von Maktrns, Riol. Cent.. 



Amer., Moll., 1900, p. 504. pJ. xxxvi, figs. 5-50. 



"From U. poeyantts. which belongs also to the Pacific slope 

 of Mexico, this form is distinct by the comparatively higher 

 shell, the height being in chapalanus a little more than one- 

 half, in pocyanus a little less than two-fifths the length."" 



Nephronaias soledadensis (Crosse and Fischer). 



"Shell inequilateral, elHptic-oblong, elongate, subcompressed, 

 narrowed in front, somewhat expanded posteriorly, rather 

 thick, epidermis olive-brown, concentrically striate; anterior 

 and posterior margins roimded ; basal margin nearly straight ; 

 dorsal margin slightly curved. Nacre a beautiful purplish- 

 violet. Right valve with two unequal pseudocardinals (the 

 upper obsolete, the lower short, thick, grooved), and a lamell- 

 iform lateral. Left valve with two pseudocardinals, the an- 

 terior small, short, the posterior larger, grooved and two 

 lamelliform laterals. Cicatrices of the anterior adductor mus- 

 cles deep, suboval : those of the posterior adductors larger,, 

 superficial, suboval. Ligament brownish, not prominent. 



Length 67, height 33, diam. 20 mm." (C. & F.) 



Type locality. La Soledad, State of Vera Cruz, Mexico. 

 Unio soledadensis Crosse and Fischer, Jl. de Con., 1893. XLL 



p. III. — Fischer and Crosse, Miss. Scient. Mex., Moll., 



1894, n, p. 608, pi. LXix, figs. 3, 30-/7. 

 Unio astecorutn var. soledadensis von Martens, Biol. Cent^ 



Amer., Moll., 1900. p. 503. 



"This species appears to belong to the group of U. a:^tec- 

 oritm Phil., from which it dififers by its larger size, more cyl- 

 indrical and less inequilateral form, its longer and more atten- 

 uated anterior extremity and more dilated posterior extremity. 

 It can be distinguished from U. popei Lea by its more rounded, 

 non-truncate and less elevated posterior end. Finally, it dif- 

 fers from U. poeyanus Lea in its less inequilateral form, the 

 non-concave ventral margin and the posterior extremity being 

 more elevated than the anterior." 



