296 ORTMANN— THE ALLEGHENIAN DIVIDE. [April 18, 



3. Pleurobema obliquum coccineum (Conr.) 



4. Pleurobema clava (Lam.) 



5. Elliptio dilatatus (Raf.) 



6. Symphynota costata (Raf.) 



7. Alasmidonta marginata (Say) 



8. Strophitus edentulus (Say) 



9. Ptychobranchus phaseolus (Hildr.) 



10. Nephronaias ligamentina (Lam.) 



11. Eurynia fabalis (Lea) 



12. Eurynia recta (Lam.) 



13. Lampsilis ovata (Say) 



14. Lampsilis ovata ventricosa (Barn.) 



15. Lampsilis midtiradiata (Lea) 



16. Truncilla perplexa rangiana (Lea) 



To these should be added, as found in tributaries of the Alle- 

 gheny in Warren Co. : 



17. Symphynota compressa Lea 



18. Anodonta grandis Say 



19. Lampsilis luteola (Lam.) 



Compared with the lower Allegheny (list no. 2), the number of 

 species has been reduced by more than a third, but for those which 

 have disappeared a few others have turned up, namely, nos. 9, 11, 17 

 and 18. Of these, Symphynota compressa (no. 17) is a peculiar 

 form restricted to the tributaries of the upper Allegheny (and also 

 in French Creek and Beaver River drainage, see above, p. 291, foot- 

 note 2). The others are species which generally prefer small 

 streams and avoid larger rivers. 



Above Warren Co., Pa., the Allegheny River flows in New York 

 state, and we have only a few records from this section (Marshall, 

 1895). But then we reach Pennsylvania again in McKean Co. 

 Here I secured a number of species in the Allegheny River, and 

 received others from Dennis Dally, and P. E. Nordgren made a col- 

 lection in Potato Creek. Here is the list of these. 



