SCAMMON : THE UNIONIDJ5 OF KANSAS, PART I. 293 



found associated with vertebrate remains of Pleistocene 

 fauna. 



Anodontoides is quite constant in its characters. The sex- 

 ual dimorphism, however, is well marked, as in all the higher 

 members of the genus Lampnlis, by the post-basal swelling 

 of the female shell. This species is liable to confusion with 

 L. recta and still more so with L. fallaciosa, to which it is 

 very closely related. A statement of the principal differences 

 will be found in the notes on the latter species. 



Lampsilis fallaciosa (Smith) Simpson. Plate LXVI, fig. 1. 



Lampsilis fallaciosus Smith, Bull. U. S. Fish Com., 1899, p. 291, pi.. 

 Lxxxix; Simpson, Proc. Acad. Nat. Sci. Phila., 1900, p. 74, pi. ll,, 

 fig. 5. 



Shell of moderate size, rather thin, decidedly elongated. 

 General outline similar to that of L. anodontoides, but the point 

 of the posterior margin is placed more dorsally. Umboidal 



ratio, 0.18 to 0.24. Umbones low and somewhat flattened, 

 their sculpture of broad A -shaped lines, very pronounced, 

 Umboidal slopes similar to L. anodontoides but with a more 

 rounded umboidal ridge Epidermis smooth and shining, a 

 clear yellow, with umbones of an ashy tinge, almost always 

 strikingly rayed with thin bands of grass- or bice-green ; 

 the rays often fused to make the posterior umboidal slope 

 solid green. The laterals and pseudocardinals of the same 

 character of anodontoides but lighter. Nacre almost always 

 salmon tinted in the shell cavity of the male but generally 

 white in the female, iridescent. 



Dorso-ven- 

 Length. Weight. Breadth. Um. ra. tral angle. 



88 38 30 0.22+ 162° c? (121.1) 

 79 33 28 .23- 160° 6" (404.1) 

 81 37 30 .19 155° 9 (121.1) 



This species is found in the upper Mississippi drainage 

 south to Tennessee and Arkans-as. There is no doubt that it 

 is also to be found in the other drainage basins of the state, 

 although I have seen specimens of it only from the Kansas 

 drainage. As Call's anodontoides includes both anodontoides 

 and fallaciosa, the later species having been established quite 

 recently, it is impossible to tell anything about the respective 

 range of the two species from his list. 



2-Bull., Vol. Ill, No, 9. 



