﻿ANODONTA 379 



Van idahucnsis Hemphill. 



"In general outline this variety is more oval than any of 

 the other forms of our West Coast Anodons. It occupies a 

 position between A. calif ornicnsis and A. oregonensis and is 

 one of those intermediate forms that are constantly occurring 

 and shake our faith in what we call species. 



In the proportions of its length and height and its rounded 

 posterior outline, it resembles Anodonta calif orniensis. In its 

 breadth between valves, and the smaller and more pointed 

 anterior end of the shell, and more especially in the less de- 

 veloped dorsal prolongations of the valves, it resembles A. 

 oregonensis. 



In color and lines of growth it agrees fairly well with both 

 of the other species. In the young state the shell is higher in 

 proportion to its length, while the wings or dorsal prolongation 

 of the valves are a little more produced. The umbones of the 

 very young of all our West Coast forms, until they have at- 

 tained about a half-inch in length, present a peculiar wavy or 

 corrugated appearance, a constant character, so far as I have 

 observed, and one that seems to have been overlooked by writ- 

 ers upon our Anodons. 



Length 214. height iV^, diam. Js inches." (Hemphill). 



Type locality, Spokane River, above Post Falls, Idaho. 

 Anodonta nv.ttaUiana var. idalioensis Hemphill, Zoe, I, i8qi, 



p. 328, pi. X. figs. 3, 4. 



ANonoNTA vvAHLAMETENSis Lea. 



Shell variable in form, irregular obovate, ovate or rhom- 

 boid, generally rather strong, scarcely inflated, quite inequilat- 

 eral ; dorsal wing well produced, angular behind ; dorsal slope 

 excavately truncated, the truncation ending below in a gener- 

 ally upturned, rounded point at or above the median line ; 

 beaks low and compressed but pointed, their sculpture con- 

 sisting of numerous, somewhat doubly looped ridges ; surface 

 irregularlv concentrically striate, soiuetimes ridged ; epidermis 

 olive or brownish, often rough but occasionally shining; nacre 



