﻿LAMFSILIS 93 



Lampsilis fallaciosus Smith, ?3u11. U. S. Fish Com., 1899, p. 



291, pi. Lxxix. — Simpson, Pr. Ac. N. Sci., Phila., 1900, p. 



74, pi. ir, fig. 5 ; Syn. 1900, p. 544. 



This has generally passed for the true anoduntoides, and 

 there are occasional specimens, which stand so completely be- 

 tween the two that they can only with difficulty be referred to 

 either. The L. fallaciosa never reaches the dimensions of 

 anodontoides, it is thinner, more delicate in every way, more 

 inflated as a rule and the hinge teeth are more compressed. 

 As a general thing it is not as high in proportion as anodon- 

 toides and the posterior point is more drawn out, and this 

 lengthening behind is especially noticeable in the male shells. 

 The fallaciosa is generally tinted with green, it sometimes is 

 all green, and it is far more likely to be rayed than its con- 

 gener. This species often has a dark flush at the umbonal 

 region, and I have seen specimens of both it and anodontoides, 

 in which the burnt brown covered the whole shell. 



Lampsiijs viRJiscENS (Lea). 



Shell long elliptical or long obovate, subinflated, subsolid. 

 with a low posterior ridge, with moderately full beaks, which 

 are sculptured with numerous, delicate ridges looped up in the 

 middle and open behind ; surface rather smooth, scarcely shin- 

 ing, greenish-straw-colored, sometimes faintly rayed, especially 

 on the posterior slope ; left valve with two compressed, elevated 

 pseudocardinals and two slightly curved, delicate laterals ; 

 right valve with two pseudocardinals, the upper smaller and 

 much compressed, and one lateral ; beak cavities rather deep ; 

 muscle scars shallow ; nacre bluish-wihite, iridescent. Both 

 male and female shells are somewhat produced at the posterior 

 base, the female but slightly more than the male, and both are 

 bluntly pointed behind midway up, or a little more than that, 

 above the center of the shell. 



Length 67, height 40, diam. 25 mm. 



Tennessee River in northern Alabama. 



Type locality, Tennessee River, Tuscumbia, Ala. 



