ORTMANN: UNIONIDZ OF WESTERN PENNSYLVANIA. 194 
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 isabsent 
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 County, 
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- 
tulus (Say) from the eastern S. wndulatus (Say). Specimens from 
the Allegheny River, and young specimens from anywhere completely 
