72 Proceedings of the Biological Society of Washington. 



Elk basin in Chester County. 



Susquehanna basin in Berks, Center, Columbia, Cumberland, Dauphin, 

 Lancaster, Luzerne, Huntingdon, Perry and Snyder Counties. 



SOLEID.E. 

 Achirus fasciatus Lac6pede. American Sole. 

 Delaware basin in Bucks and Philadelphia Counties. 



GADID.E. 

 Lota maculosa (Le Sueur). Burbot. 

 Found at Erie. Introduced in the Susquehanna and Delaware. 



Besides the species already indicated as introduced are several others 

 and several which may be considered accidental Such are: 



Carcharias taurus Rafinesque. Sand Shark. 

 Once recorded in the region of the Delaware opposite Philadelphia. 



Eulamia milberti Muller and Henle. Brown Shark. 

 Once found in the Delaware opposite lower Philadelphia. 



Raja ocellata Mitchill. Big Spotted Skate. 

 Once in the Delaware opposite upper Philadelphia. 



Oncorhynchus tschawytscha (Walbaum). Quinnat Salmon. 

 Introduced in the Delaware and Susquehanna. 



Salmo salar Linnaeus. Salmon. 

 Introduced in the Delaware. 



Salmo salar sebago (Girard). Landlocked Salmon. 

 Introduced in Luzerne, Monroe, Pike and Wayne Counties. 



Salmo fario Linnaeus. Brown Trout. 

 Introduced in Blair, Huntingdon, Luzerne, Monroe, Philadelphia, Pike 

 and Wayne Counties. 



Salmo clarkii Richardson. Columbia River Trout. 

 Introduced in Center and Susquehanna Counties. 



Salmo irideus Gibbons. Rainbow Trout. 

 Introduced in Center, Clearfield, Cumberland, Fayette, Franklin, Mont- 

 gomery, Pike, Wayne and Wyoming Counties. 



Thymallus tricolor Cope. Michigan Grayling. 

 Introduced. 



