Vol. XIV, pp. 153-155 August 9, 1901 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



ON THE MAINLAND FORMS OF THE EASTERN 



DEERMOUSE, PEBOMYSCUS LEVCOPUS 



(RAFINESQUE). 



BY EDGAR A. MEARNS. 



Peromyscus leacoj^ns was originally described by Raiinesque 

 from specimens taken during a journey through ''the lower 

 parts of the Ohio, the Wabash, Green River, Barrens, Prairies, 

 and the states of Indiana, Illinois, &e." Kentucky is genei-al- 

 ly considered to be the type locality.* Specimens from Lex- 

 ington, Kentucky, collected by the writer and assumed to be 

 typical, are found to agree with those from other |»arts of the 

 austral zone east of the Mississippi River; but, in the transi- 

 tion zone, fairly well-marked geographical races occur in New 

 York and New England in the East, and in Minnesota in the 

 West. The range of the species does not extend beyond the 

 northern boun<lary of the transition zone, but meets with that 

 of Peronn/xrns (•diuidensis at the lower vi.V^v of the boreal zone. 

 In these forms, which may be recognized by the following de- 

 scriptions, the under surfaces are white with more or less gi'ay 



*In a letter "ddteil at Louixdlli; Fallx of Ohio, -IWh .Julii, 1S18", pub- 

 lished in the American Monthly Magazine, Vol. Ill, September, 1818, p. 

 354, Rafinesque states respecting ''Qiiadrupfdf'-. "I have discovered 

 and described ."5 new species: 1. Mittsrulux hucopus; 2. Gerbillun Sylvati- 

 cux; and, 3. Nurtilio myittdx. Rat". " 



30— BIOL. SOC. WASH. VOL. XIV, 1901. (153) 



