﻿164 l.AMl'SII.IS 



Var. poulsoni (Conrad). 



More solid and inflated than typical shells and narrower in 

 front. The two [xtsterior ridges are quite distinctly developed, 

 the outlne from the hinder end of the post-dorsal wing to the 

 end of the upper ridge is incurved, and that between the two 

 ridges is often incurved. Its surface is rougher than in the 

 type, and the teeth are rather heavier. This may almost be 

 considered a distinct species, but it is connected with typical 

 forms by an abundance of material in the Tennessee region. 



Length 123, height 80, diam. 43 mm. 



Alabama and Tombigbee Systems. 



Type locality, F>lack Warrior River, Ala. 

 Unio ponlsoni Conrad, New F. W. Shells, 1834, p. 25, pi. i; 



p. 71. — Chenu, Bib. Conch., ist sen. III, 1845, p. 15, pi. i, 



fig- 7- 

 Symphynota ponlsoni Fkrussac, Guer. Mag.. 1835, p. 25. 

 Lampsilis aUitKs var. poulsom Simpson, Syn.. 1900, p. 568. 



This species is solider, darker colored and has darker nacre 

 than L. gracilis and Uci'issima, with which it is most often asso- 

 ciated. The female shell is more produced in the post-basal 

 region than in either of those species. It is less inflated and 

 ponderous than L. purpurata. 



Lampsilis coloraixiensis (Lea). 



Shell large, irregularly obovate, subsolid, with a rather dis- 

 tinct posterior ridge and two slightly elevated, dark, radial 

 ridges on the posterior slope ; beaks somewhat full and high, 

 their sculpture consisting of corrugated, doubly-looped ridges ; 

 posterior wing broken off down to the large ligament in half 

 grown to adult shells ; surface with irregular growth lines, pale 

 smoky-brown, nebulously banded and rayed with olive ; left 

 valve with two ragged, elevated, subcompressed pseudocar- 

 dinals, the anterior the larger, and two short, remote laterals ; 

 right valve with two pseutlocardinals, the upper smaller, and 

 one high, truncated lateral ; beak cavities moderately deep, with 

 an irregular row of i)its running towards the anterior base ; 

 anterior scars deep, separate ; posterior scars large and shal- 



