196 Annals of the Carnegie Museum. 



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 ifi the rest of 

 the Allegheny drainage, in the Ohio, and in the whole Monongahela 

 drainage. 



29. Symphynota (Lasmigona) costata (Rafinesque). 



It is cited as Margarita iia ri/gosa 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 is so 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. Alasmidonta (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, 1901, p. t6) and Fox (ibid., 

 p. 47), the western form is the true marginata of Say ( = tnincata 



