191 Annals of the Carnegie Museum. 



There are in the Carnegie Museum two dead specimens from the 

 Monongahela at Charleroi, Washington County (Ehrmannn Collec- 

 tion), and the present writer has found four others (two of them alive) 

 in the Ohio in Beaver County. 



23. Ptychobranchus phaseolus (Hildreth). 



Mentioned in Harn's list from western Pennsylvania ; not recorded 

 in the lists of Stupakoff and Clapp ; given by Rhoads as from the 

 Beaver at Wampum, but not from the Ohio. 



The species is widely distributed in the smaller streams of western 

 Pennsylvania, while it is lacking in the large rivers. It occurs every- 

 where in the Beaver drainage in Lawrence and Beaver Counties ; in 

 the little Beaver and Raccoon Creeks in Beaver County ; in Dunkard 

 Creek in Greene County, and the Cheat River, Fayette County ; in 

 the Kiskiminetas drainage in the upper Loyalhanna in Westmoreland 

 County ; and the Quemahoning Creek in Somerset County. While 

 rare in the Allegheny in Venango and Forest Counties, and absent in 

 the Allegheny below Oil City, it occurs practically in all its tribu- 

 taries, in Connewango Creek, French Creek, and Little Mahoning 

 Creek, Indiana County, and Buffalo Creek, Butler County. It is absent 

 in the Ohio, but used to be found in the Monongahela at Charleroi. 



24. Strophitus undulatus (Say). 



It occurs in Harn's list as from western Pennsylvania ; but is not 

 reported by Stupakoff and Clapp. It is mentioned in Rhoads' list 

 from the Ohio and Beaver. 



In the Ohio drainage in western Pennsylvania this species is found 

 practically everywhere, and it goes eastward into Somerset Cqunty, 

 occurring in Quemahoning Creek and the Youghiogheny River. In 

 the latter river, it is the only Unionid found above Confluence. Some 

 forty individuals were collected, while there was not a trace of any 

 other species, a very remarkable fact indeed. It is further found east- 

 ward in Indiana, Forest, and Warren Counties. This species is rather 

 scarce in the large rivers ; though Rhoads found it in the Ohio below 

 Pittsburgh, I have never seen it there. Nevertheless it occurs in the 

 Allegheny in Armstrong County, though the specimens are rather 

 small. The finest and largest specimens are encountered in certain 

 small creeks in the northwestern section of the state. 



It is impossible for me to separate the western, so called, ^S". eden- 

 tiilas (Say) from the eastern S. undulatus (Say). Specimens from 

 the Allegheny River, and young specimens from anywhere completely 



