22 The American Naturalist. [January, 



A. plana Lea. 



Immense specimens of this species over eight inches long 

 inhabit a small pond in Stratsboro township. 

 A. imbecilis Say. 



Very rare here. One specimen from Lake Brady and one 

 from a small pond in Franklin township. They have not the 

 beautiful bluish green tint of Ohio river specimens. Recently 

 Mr. Streator reports this species in considerable numbers from 

 the Cuyahoga river in the north part of Hiram township. 



Genus Margaritana Schum. 

 M. rugosa Lea. 



This robust and plentiful species in the larger streams is com- 

 paratively rare here, but I have seen it in the Cuyahoga and 

 it is probably found in Silver Creek and other tributaries of 

 the Mahoning. 

 M. complanata Lea. 



M. marginata Say. 



In Silver Creek and doubtless other branches of the Mahon- 

 ing, but not very common. 



Genua Unio Retz. 



U. coccineus Lea. 



Silver Creek, Windham township. 

 Unio gibbosus Barnes. 



Silver Creek, Windham township. Common. 

 U. luteolus Lam. 



Common and abundant in all the larger streams. 

 U. namtus Say. 



Common in many of the lakes and small streams and abun- 

 dant in the Cuyahoga. 

 U. pressus Lea. 



U. undulatus Barnes. 



Silver Creek, Windham and doubtles. ()t her tributaries of 

 the Mahoning. 



U. occidens Lea. Branches of the Mahonine but not abun- 

 dant. This form of occnlfm* is identi,-,' »•;.!, r < t ,l,m<nt,i* Lea. 



