50 



MEMOIRS OF THE CARNEGIE MUSEUM. 



Allegheny, Armstrong Co., Pennsylvania to Parkersburg, West Virginia, but in 

 company with the normal form. They should be called wardi, but do not form a 

 distinct race, but are rather individual variations. 



It is interesting to note, that outside of our state, nearly all specimens from 

 small rivers and creeks, such as West Fork River, the Little Kanawha, and Coal 





Fig. 6. 



■ Quadrula metanevra. 

 • Qiiadnila cylindrica. 



River, belong to this form called ivardi, and it may be, that in such small streams, 

 the wardi-type becomes the prevailing one, thus forming an ecological race. Sterki 

 (1907a, p. 390) mentions such a case from Sugar Creek, a small tributary of the 

 Tuscarawas River in Ohio. 



Localities in Pennsylvania, represented in the Carnegie Museum: 



Ohio River, Shippingport, Cooks Ferry, and ludustrj^, Beaver Co.; Coraopolis (S. N. Rhoads) and 



Neville Island, Allegheny Co. 

 Allegheny River, Aladdin, Godfrej', Johnetta, Kelly, and Templeton, Armstrong Co. 

 Monongahela River, Charleroi, Washington Co. (G. A. Ehrmann). 



Locality in Pennsylvania, represented in the Philadelphia Academy of Natural 

 Sciences: 



Ohio River, Beaver, Beaver Co. (S. N. Rhoads). 



Other localities represented in the Carnegie Museum: 



Ohio-drainage: 

 Ohio River, Toronto, Jefferson Co., Ohio; Wheeling, Ohio Co., West Virginia (W. F. Graham); Claring- 



ton, Monroe Co., Ohio; St. Marys, Pleasants Co., West Virginia; Parkersburg, Wood Co., West 



Virginia; Portland, Meigs Co., Ohio; Portsmouth, Scioto Co., Oliio. 

 West Fork River, West Milford, Hfirrjson Co., West Virginia (W. F. Graham). 



