﻿92 I.AMPSII.IS 



crally less rayed. There arc occasional specimens of tlie va- 

 riety that arc feebly rayed. 



I have no donht lint that Lea inclndcd in his descri])tion both 

 (inodonfoldcs and fallaciosa, for he says that the shell is some- 

 times almost cylindrical and aj^ain that "in some specimens, the 

 arcuation of the basal marjT:in is so g^rcat that it might almost 

 be taken for a malformation." But his figure shows the heavy, 

 higher, unicolored, larger sliell, that of a female, with rather 

 solid pseudocardinals and we are therefore compelled to accept 

 this for his species. 



Lampsii.is FAIJ<.^CIOSA (Smith) Simpson. 



Shell elongated, the hinge and ventral lines nearly parallel, 

 smbcylindrical, subsolid, generally inflated ; beaks full but not 

 high, their sculpture numerous, distinct, fine ridges looped up 

 in the center, open behind ; ligament long, brown, rather nar- 

 row ; anterior end rounded ; posterior part ending in a rather 

 sharp point more than midway up from the base of the shell ; 

 surface very smooth and glossy, slightly concentrically ridged 

 at the anterior end ; color greenish-yellow or yellowish-green, 

 often faintly rayed and always darker on the posterior slope. 

 Left valve with two high, compressed pseudocardinals and 

 two delicate, nearly straight, laterals ; right valve with two 

 pseudocardinals, the upper smaller and more compressed and 

 one lateral ; beak cavities moderate ; muscle scars well impress- 

 ed ; nacre white, straw-colored or salmon-tinted. 



Length (male) 90, height 37, diam. 32 mm. 



Length (female) 90, height 40. diam. 33 mm. 



Upper Mississippi drainage ; south to the Cumberland River, 

 Tennessee, and to Arkansas ; Red River of the North ? 

 Uftio anodontoides Reeve, Conch. Icon., XVI, 1865, pi. xxi, 



fig- 97- 

 Lompsilis anodontoides Rakkr, Moll. Chicago, Pt. 1. i8()8, pi. 



X. fig. 3- 

 Unio oriens Sowerby, Conch. Icon., X\"I. 1868. pi. lxiii, fig.. 

 3M- 



