﻿l68 I.AMI'SIIJS 



slope; left valve with a lon^^ low, feebly developed pseudo- 

 cardinal, which is somewhat divided in the middle, and two 

 remote, delicate laterals ; right valve with a single compressed 

 pseiidocardinal and one high, truncated lateral ; beak cavities 

 shallow, with a row of pits ; muscle scars superficial ; nacre 

 blue, becoming somewhat lurid at the beak cavities. The only 

 shell I have seen is the type, which is probably a young female. 

 It is somewhat rhomboid behind and well developed into a mar- 

 supial swelling at the extreme posterior base. The front end 

 of the shell is narrow. 



Length 55, height 37, diam. 20 mm. 



Type locality, Tombigbee River, Columbus, Mississippi. 

 Unio pcrniiscens I.i:a. Pr. Ac. N. Sci. Phila., Ill, 1859, p. ii2,- 



Jl. Ac. N. Sci. Phila., V, 1862, p. 102, pi. xvii, fig. 251 ; Obs., 



YIII, 1862, p. 106, pi. XVII, fig. 251. 

 Margaron (Unio) permiscens Lra, Syn., 1870, p. 61. 

 Lampsilis peniiiscens Simpson, Syn., 1900, p. 56c). 



This is undoubtedly a young shell and not in the best condi- 

 tion. It is not unlikely that it is a young L. piirpurata. 



Lampsilis gouldii (Lea). 



Shell almost regularly elliptical, a very little wider behind 

 than in front, subsolid, not inflated, with a low posterior ridge 

 and two radiating, slightly raised, darker ridges above it ; beaks 

 probably not high, so eroded in the only specimen seen that 

 nothing can be made out from them ; posterior base a little full ; 

 surface with irregular growth lines, covered with a dark brown 

 epidermis ; left valve with two small pseudocardinals, the an- 

 terior slightly compressed, the posterior stumpy, and two re- 

 mote, curved laterals ; right valve with one pseudocardinal and 

 one lateral ; beak cavities not deep ; muscle scars shallow, the 

 hinder faint ; nacre bluish-white, slightly thicker in front. 



Length 50, height 29, diam. 17 mm. 



Type locality. Tuscaloosa, Alabama. 

 Unto gouldii hv.A, Pr. Am. Phil. Soc., IV. 1845, p. 165 ; Tr. 



AmrPhil. Soc, X, 1848. p. 76. pi. VI. fig. 16; Obs., IV, 1848. 



p. 50. pi. VI. fig. 16. 

 Margaron (Unio) gouldii Lka, Syn., 1852, p. 29; 1870. p. 46. 

 Lampsilis gotddii Simpson, Syn., 1900, p. 569. 



