190S.] 



MAMMALS. 



173 



Sciuropterus sabrinus alpinus (Eicliardsoii). Mountain Fhdng 

 Squirrel. 



This flying squirrel is mainly an inhabitant of the Rocky ^loun- 

 tain range from the Jasper House region northward at least to Liard 

 River. To the eastward of the mountains it apparently grades into 

 sabrinus, as before stated. 



"Pterojnys sahrrnus var. aJphius ' was described by Richardson from 

 specimens taken by Drummond near the sources of Elk River 

 [Athabaska].« Two specimens, male and female, taken by D. E. 

 Xoyes at Jasper House. Alberta. December 15. 1896. can thus be 

 considered typical. Compared Avith winter skins of *S. sab) hius from 

 Xorway House, and skins without date from Oxford House and 

 Hudson Bay. the Jasper House specimens are much less rufous, 

 the general color above being sepia or gra34sh-bister : the tail is 

 much darker, being dusky-brownish above and but slightly lighter 

 beneath: the upper surfaces of the feet are darker: the lower parts 

 are dull grayish-white, tinged with fawn, not conspicuously differ- 

 ent from S. sab/ hi U.S. 



A specimen, not fully adult, taken by Ub on tlie Athabaska about 

 60 miles above Grand Rapid August 2.5. 1901, agrees closely with 

 the Jasper House specimens. In December. 1903, while at Fort 

 Simpson. I received a flying squirrel from Joseph Hodgson, of Fort 

 Providence, where it was taken about December 7. It is a male, 

 evidently a young one of the previous summer, and measured: Total 

 length 310. tail vertebra? 110. hind foot 39. The molt had been 

 retarded, and the specimen is consequently in poor pelage. The 

 general duskiness of both surfaces of the tail and the lack of 

 brownish suffusion on the back indicate that this specimen should 

 be referred to S. alpinux. 



Two specimens, both males, taken at Fort Simpson March 11, 1905, 

 ha\"e been received recently from J. W. ^lills, who writes that they 

 were found in a nest on the branches of a tree, evidently a repaired 

 l)ird's nest. These specimens evidently are referable to S. alpinus, 

 though perhaps slightly inclining toward sabrimis. They are 

 slightly more rufous on the back than the topotypes of alpiwis, but 

 agree in having the tails much suffused with sooty. The upper sur- 

 faces of the hind feet also are ver}" dark, as in typical alpinus. The 

 measurements, reduced to millimeters, are as follows: Total length 

 318. tail vertebrae 116, hind foot 39: and 305. 127. 36. The skulls are 

 smaller than the topotypes of S. alpinus, due evidently to imma- 

 turity, but show no striking peculiarities. 



^Zool, .Journ.. Ill, No. XII, p. 519, 182S. (See also Fauna Boreali-Ameri- 

 cana, I, p. 195, 1829.) 



