1924] Swarth: Birds and Mammals of the Skeena River Region 375 



satisfactory to use. There are some differences apparent between the 

 series from the three different localities. Among the mice taken at 

 Hazelton there is a preponderance of small, short-tailed, bright- 

 colored specimens (boreali^-like) and there are no large, long-tailed 

 individuals. From Eispiox Valley and Nine-mile Mountain there are 

 certain large, long-tailed, dark-colored specimens (macrorhimis-]ike) , 

 and there is none that is as near typical iorealis as are some specimens 

 in the Hazelton series. The darker colored mice differ from typical 

 macrorhdnus in their duller shades; they lack the rich brown apparent 

 in coastal specimens of macrorhinus. 



Skulls, also, in size and character are variously intermediate 

 between horealis and macrorhinus. There is individual variation, 

 notably in the series from Nine-mile Mountain, some skulls being 

 generally long and slender, especially as regards the rostrum, others 

 more short and broad. 



The differences between the series from Hazelton and those from 

 Kispiox Valley and Nine-mile Mountain are not obviously correlated 

 with geographic position; for Hazelton, v/ith the more lorealis-like 

 mice, is nearest the habitat of macrorhinus, and in a broad valley that 

 leads direct to the coast. 



Individual variation obtains in each series to a notable extent. 

 Relative length of tail is a conspicuously variable feature, apparent 

 as soon as the animals were handled. Other variations appeared upon 

 closer study. It may be suggested that two distinct forms are repre- 

 sented in the series under discussion, but in contravention to this idea 

 is the fact that the several distinguishing characters of either sub- 

 species are not always uniformly developed in the same specimen. Size, 

 color, length of tail, and character of skull, are the characters used 

 in differentiating these races, and some individuals possess certain 

 features more nearly like one subspecies, some that are more nearly 

 like the other. 



It will take many specimens representing numerous localities in 

 northern and central British Columbia, to demonstrate the distribution 

 and relationships of the forms of Peromyscus maniculatus occurring in 

 that general region. In the northern interior of the province i,s horealis, 

 on the northern coast is macrorhvnus, at the southwest is oreas, and 

 at the southeast, artemime. These subspecies are distinct enough at 

 the centers of their respective ranges, but at the edges of their habitats 

 there are many difficulties in the way of satisfactory allocation of 

 specimens. It will require an immense amount of detailed work to 



