﻿90 i,AMPSir,is 



smooth and shininj^, but feebly rayed ; beaks not prominent, 

 marked with very delicate, regular sculpture, the j)osterior loop 

 often open behind ; pseudocardinals smooth, generally com- 

 pressed ; nacre shining, white or purplish. Animal having the 

 marsupium very distinct and well rounded below ; inner edge 

 of the mantle usually beautifully and evenly toothed behind. 



LaMTSILIS ANODONTOIDES (lyCa). 



Shell large, elongated, with dorsal and ventral lines nearly 

 parallel, rounded in front, poinlted behind, more or less inflated, 

 solid ; beaks rather full but not high, their sculpture consisting 

 of numerous, distinct ridges looped in the middle but open be- 

 hind ; posterior ridge low and rounded ; surface smooth and 

 shining, but often having concentric growth ridges in frortt, 

 tawny to pale straw-color, sometimes with a few rays on the 

 posterior slope, the rest of the shell generally rayless ; there 

 is often a large, brown flush in the umbonal region ; ligament 

 large and long ; left valve with two subcomprcssed pseudocar- 

 dinals,. the hinder somewhat elongated, and two long, nearly 

 straight, delicate laterals ; right valve with two pseudocardi- 

 nals, the upper faint, and one lateral ; beak cavities not deep ; 

 muscle scars rather large, well impressed ; nacre white, cream- 

 colored, salmon-tinted or pinlc, slightly thicker in front. Both 

 male and female shells end behind in a point two-thirds of the 

 way up from tlie base ; the female shell has a large, rounded 

 marsupial swelling and is slightly incurved at the central base. 



Length (male) 127, height 62, diam. 45 mm. 



Length (female) 120, height 62, diam. 45 mm. 



Entire Mississippi River drainage except (probably) the up- 

 per Missouri. All the Gulf drainage from the Withlacoochee 

 River, Florida, to the Rio Grande, and into Mexico. 



Type locality, Mississippi, Alabama and Ohio Rivers. 

 Unio anodontoides Lua, Tr. Am. Phil. Soc, IV, 1834, p. 81, 



pi. VIII, fig. II ; Obs., I, 1834, p. 91, pi. VIII, fig. II.— Chhnu, 



III. Conch., 1858, pi. XIV, figs. 3, 3a, 3^.— Reevk, Conch. Icon., 



XVI, 1865, pi. XIX, fig. 87.— Simpson, Proc. U. S. Nat. 



MUS., XV, 1892, p. 430, pi. LXXI, fig. 7, pi. LXXII, figs. I, 2, 4. 



