MAMMALS OF PENNSYLVANIA AND NEW JERSEY. 67 



1758. \_Mus\ volans Linnaeus, Systema Naturae, vol. i, p. 63. 



1890. S\_ciuropterus~\ volans Jordan, Manual Vertebrate Animals, Northern 

 U. States, p. 321. 



Type locality, Virginia. 



Faunal distribution. Austral and transition zones; Maine to Georgia, 

 west to the plains. . - 



Distribution in Pa. and N.J. Found in uniform abundance in all locali- 

 ties, so far as known. Whether it is replaced in any of the restricted Cana- 

 dian areas by the large northern species, Sciuropterus sabrinus macrotis 

 Mearns, has not been determined. All the flying squirrels so far examined 

 by me from these localities have been the small species, S. volans. As there 

 is a possibility of the larger species being found, the following distinctions 

 between them may be given : 



Description of species. The Virginia species is drab on the upper parts, 

 slightly shaded with russet, not distinctly different in winter and summer fur. 

 The under parts are pure white to the extreme roots of the hairs. The total 

 length is 230 mm. (9 in.) ; tail vertebrae 100 (4) ; and hind foot 30 (i^). 

 In the northern species these measurements are respectively : 280 (n) ; 125 

 (5) ; 38 (ij) j and the upper parts are glossy wood brown mixed with 

 cinnamon in winter and in summer sooty drab, the under parts being dirty 

 white, the hairs sooty at their roots. 



Family CASTORID/E, Beavers. 

 Genus Castor Linnaeus, Systema Naturae, 1758, vol. i, p. 58. 



Northeastern or Canada Beaver. Castor canadensis Kuhl, 1820. 

 Castor canadensis Kuhl, Beitrage Zur. Zool. u. Vergl. Anat., p. 64. 



Type locality. Hudson Bay. 



Faunal distribution. Hudsonian and Canadian life zones; Atlantic Ocean 

 to Cascade Mts. and Behring Sea. 



Distribution in Pa. and N. J. The typical form was never found in N. J. 

 In Pa. this northern animal was at one time numerous in the higher mountain 

 lakes and headwaters of the Allegheny and Susquehanna rivers. It is in- 

 cluded in this paper solely on our knowledge of the presence of other animal 

 forms belonging to the Canadian fauna (Lynx, Wolverene, Bonaparte's 

 Weasel, Cope's Shrew, etc.) in the regions named. No specimens of native 

 beaver from Pa. or N. J. being known to exist, I have been compelled to in- 

 clude both the northeastern (canadensis^ and the southeastern (carolinensis} 

 in this list on purely zoogeographic grounds. I have no hesitation in believ- 

 ing that this course would be proven correct on a basis of comparison be- 



