I9I3-] ORTMAXX— THE ALLEGHEXIAX DIVIDE. 313 



B. ATLANTIC SIDE. 



Besides the writer's own investigations, the following publica- 

 tions have been used for compilation of the faunistic lists : 



For Delaware, Suscjuehanna, and Potomac rivers: Gabb, 1861 ; 

 Hartnian and Alichener, 1874; Pilsbry, 1894; Schick, 1895; Caffrey, 

 1911. 



For James River: Conrad, 1846. 



Since the Atlantic side does not form a single drainage system, 

 but consists of a number of rivers running independently to the sea, 

 we must discuss these rivers separately. 



I. The Fauna of the Delaware River. 



This is the most northern system in the region discussed here. 

 The following Xajades are known to exist here: 



List No. ly. 



1. Margaritana inargaritifera (L.) 



2. ElUptio complanatus (Dillw.) 



3. EUiptio fisheriajiiis (Lea) 



4. Syinphynota fappaiiiana (Lea) 



5. Anodonta cataracta Say 



6. Anodonta iinplicata Say 



7. Alasmidonta heterodon (Lea) 



8. Alasmidonta undiilata (Say) 



9. Alasmidonta varicosa (Lam.) 



10. Stropliitits undulatus (Say) 



11. Stropliitns cdcntnlus (Say) 



12. Eurynia nasuta (Say) 



13. Lampsilis radiata (Gmel.) 



14. Lampsilis cariosa (Say) 



15. Lampsilis ochracea (Say) 



It is to be remarked that no. 3, no. 10 and no. 15 are found ex- 

 clusively in the tidewater region of the lower Delaware and Schuyl- 

 kill, and that no. 3 is at the best extremely rare (only once reported), 

 and that no. 10 is altogether a doubtful form. Xo. i is very local 

 (uppermost Schuylkill). 



