ORTMANN: UNIONID@ OF WESTERN PENNSYLVANIA. 196 
28. Symphynota compressa ( Deshayes). 
The only previous record is that of Rhoads from the Beaver at 
Wampum, Lawrence County. 
In addition it has been found in Little Beaver Creek in Beaver 
County, in the whole Beaver drainage in Beaver, Lawrence, Mercer, 
and Crawford Counties, in French Creek and its tributaries in Ve- 
nango, Crawford, and Erie Counties, and in Brokenstraw and Conne- 
wango Creeks in Warren County. It is entirely absent in the rest of 
the Allegheny drainage, in the Ohio, and in the whole Monongahela 
drainage. 
29. Symphynota (Lasmigona) costata (Rafinesque). 
It is cited as Wargarttana rugosa Barnes in Harn’s, Stupakoff’s and 
Rhoads’ lists from western Pennsylvania, Allegheny County, and the 
Ohio and Beaver Rivers. 
Generally distributed over the Ohio drainage in the state, eastward 
as far as Fayette County (Cheat River), Somerset County (Quema- 
honing Creek), Indiana County (Two Lick, Crooked, and Little Ma- 
honing Creeks), and McKean County (upper Allegheny River). It 
extends northward into Crawford and Erie Counties (upper Shenango 
River, French and Conneauttee Creeks). In some of the smaller 
creeks it isso abundant as to become the prevailing form (Little 
Beaver, Loyalhanna, Little Mahoning). On the other hand, it is 
rather scarce in the large rivers. I have never found it in the Ohio 
in Beaver County, and only a few individuals in the Allegheny in 
Armstrong County. 
30. Symphynota (Pterosygna) complanata (Barnes). 
Never reported before from the state. I have found a number of 
specimens in Conneaut Outlet, Crawford County, and a few dead ones 
(from a muskrat hole) in Leboeuf Creek, just below Lake Leboeuf, 
Erie County. 
31. Alasmigonta (Rugifera) marginata (Say). 
Reported by Harn from western Pennsylvania, and by Rhoads from 
the Ohio and Beaver Rivers. 
It is quite generally distributed over the Ohio drainage, going up 
into the head-waters to Somerset, Westmoreland, Indiana, and McKean 
Counties. It is rare in the large rivers, but in the small streams locally 
abundant. 
According to Pilsbry (Nautilus, 15, rg01, p. 16) and Fox (ibid., 
p. 47), the western form is the true marginata of Say ( = truncata 
