Arctic Deermouse 



491 



The genus Peromyscus (Gloger, 1841) comprises Mice of 

 about the size of a House-mouse, but distinguished by their 

 cheek pouches and pecuHar upper molars, etc. (See Fig. 144.) 

 They have large prominent eyes and ears, soft fur which 

 is gray or brown above and white below; long tail, usually bi- 

 coloured. 



Teeth: Inc. 



i-i 

 i-i 



mol. 





16 



The immensely complicated synonomy of the group 

 Peromyscus maniculatus is much less complicated than the 

 relationships of the many 

 subspecies that are sup- 

 posed to belong to it. In 

 the present state of our 

 knowledge it is impos- 

 sible to offer a satisfac- 

 tory digest of the facts. 



Temperate North 

 America, in general, is 

 inhabitated by a wide- 

 spread, highly plastic, 

 long-tailed, white-footed 

 Wood-mouse, called 

 maniculatus. This Is split 

 up into many intergra- 

 dient forms, of which three find a meeting ground in 

 Manitoba. 



These, according to W. H. Osgood, to whom I am in- 

 debted for essential aid In treating the present species, are 

 arcticus, nehrascensis, and batrdt. 



In addition to the generic characters a fairly typical 

 specimen of arcticus taken at Winnipegosis, August, 30, 1904, 

 has the following: 



Length, 7I inches (184 mm.); tail, 2>\ inches (82 mm.); size 

 hind-foot, if inch (21 mm.). 



Fig. 144 — Upper diagram, left upper molars of genus 



Peroviyscus. 



Lower diagram, left upper molars of genus Miu. 



(Both greatly enlarged.) 



