Ortmann : Unionid.b of Western Pennsylvania. 205 



4. Lampsilis nasuta (Say). 



Reported from the Delaware and Schuylkill Rivers, and " Little 

 Perkiomen Creek" (Gabb). Perkiomen Creek is a tributary of the 

 Schuylkill in Montgomery County, but there is, as far as I can ascer- 

 tain, no stream known now as " Little Perkiomen Creek." This 

 species has not been reported from the Susquehanna drainage. 



The Carnegie Museum has specimens from the Delaware at Penn's 

 Manor and at Yardley, Bucks County (Ortmann). 



5. Strophitus undulatus (Say). 



The species has been reported from the Schuylkill (Lea) ; Brandy- 

 wine Creek, Chester County (Hartman & Michener) ; Crum Creek, 

 Delaware County (Lea) ; Schuylkill Canal, Philadelphia County 

 (Schick) ; and from Lancaster County (Bruckhart). 



In the Carnegie Museum it is represented by specimens from the 

 following localities: Delaware River, Penn's Manor and Yardley, 

 Bucks County (Ortmann) ; Little Neshaminy Creek, Grenoble, 

 Bucks County (Ortmann) ; Schuylkill Canal, (H. J. Gera), and 

 Schuylkill River, Manayunk, Philadelphia County (Ortmann) ; 

 Middle Creek, Freeburg, Snyder County (Atkinson) ; West Branch 

 Mahantango Creek, Richfield, Juniata County (Atkinson); Cocolamus 

 Creek, Cocolamus, and Lost Creek, Mifflintown, Juniata County (At- 

 kinson) ; Raystown Branch of the Juniata River, Everett, Bedford 

 County (P. E. Nordgren) ; Beaver Dam Creek, Flinton, Cambria 

 County (Atkinson) ; Swartz Run, Ashville, Cambria County (Ort- 

 mann) ; Cush-Cushion Creek, Green Township, Indiana County 

 (Atkinson and Ortmann). 



This species is generally small in eastern Pennsylvania, representing 

 the typical undulatus. Yet locally it attains considerable size, for 

 instance in Little Neshaminy Creek, in Beaver Dam, and in Cush- 

 Cushion Creek. In fact specimens from the latter creek (abandoned 

 reservoir) are the largest I possess, larger than any from western 

 Pennsylvania. According to Simpson, both forms, utululatus and 

 edentulus, are found in the Atlantic drainage, but my material shows 

 that large and small individuals cannot be separated as species, be- 

 cause they pass gradually into each other. There are small ones from 

 Cush-Cushion Creek, which agree perfectly with specimens of the 

 same size from other localities farther east. Compare notes under 

 this species in the Ohio drainage. 



6. Anodonta cataracta Say. 



