﻿LAMPSILIS 73 



with strong concentric ridges, rather shining, buff, straw-col- 

 ored or greenish-yellow, often having faint rays on the pos- 

 terior slope, and sometimes a few faint ones on the body of 

 the shell ; each valve having two pseudocardinals, the upper 

 one in the right being compressed and smaller ; left valve with 

 two lamellar laterals; right valve with one lateral; beak cavi- 

 ties moderately deep ; anterior muscle scars impressed ; pos- 

 terior scars faint ; nacre bluish-white, rather dull, often with 

 a dark spot in the region of the beak cavities, scarcely thick- 

 ened in front. Male shell pointed behind, about midway up 

 from the base ; female shell often much produced at the pos- 

 terior base, rounded or subtruncate behind. 



Length (male) 80, height 50, diam. 30 mm. 



Length (female) 70, height 50, diam. 30 mm. 



Southern Alabama, southern Mississippi. 



Type locality, small streams in southern Alabama. 

 Unio stramineus Conrad, Am. Jl. Sci., XXV, 1834, p. 339, pi. 



I, fig. 6; Monog., X, 1838, p. 91, pi. l, fig. i. — Hanley, BiV. 



Shells, 1843, P- 209, pi. XXIII, fig. 45. — SowERBY, Conch. 



Icon., XVL 1866, pi. XXXIX, fig. 217 ; 1868, pi. lxxx, fig. 422. 

 Margarita (Unio) stramineus Lea, Syn., 1836, p. 39; 1838, p. 



25- 

 Margaron (Unio) stramineus Lea, Syn., 1852, p. 28; 1870, p. 



35- 

 Lampsilis stramineus Simpson, Syn., 1900, p. 538. 



The shell is of rather light structure and the concentric 

 sculpture is almost always well developed. Frequently the con- 

 centric ridges are very strong and regular. 



Lampsilis bracteata (Gould). 



Shell elliptical, thin to subsolid, somewhat inflated, with a 

 scarcely perceptible rounded post-ridge; beaks not elevated, 

 sculptured with rather fine, distinctly doubly-looped ridges ; 

 growth lines irregular ; surface either smooth or irregularly 

 sulcatc, somewhat shining, greenish straw-colored with nu- 

 merous irregular, wavy, narrow and broad rays ; left valve 



