ocT.,1900.] MAMMALS OF THE YUKON REGION". 55 



Evotomys dawsoni alascensis (Miller). Tundra Red-backed Mouse. 

 Bvotomys alascensis Miller, Proc. Acad. Nat. Sci. Phila., 1898, 364-367. 



The Evoto-inys found at St. Michael has heretofore been compared 

 only with the Asiatic E. Tutilus. Its closest relationship is really with 

 E. dawsoni^ with which its range is doubtless continuous. On com- 

 paring the series secured at St. Michael with those in the same condi- 

 tion of pelage from Rink Rapids,^ Northwest Territory, I am unable 

 to find even the slightest difference in color or size. The skull of 

 alascensis is slightly characterized by small, narrow molar series, and 

 by nasals which have their posterior end truncate. The palate and 

 audital bullse are not peculiar. The tail is often thick and bristly in 

 winter pelage and in immature specimens of both dmmoni and alascen- 

 sis. From this it appears that alascensis may be only a slightly 

 marked subspecies. 



The favorite habitat of these mice about St. Michael is in the heaps 

 of broken lava scattered about over the tundra. The}^ are very rarely 

 taken in the Miarotus runways. They are common in the warehouses, 

 which they seem to enter more readily than other mice of the tundra. 



Microtus mordax (Merriam). liong-tailed Vole. 



Specimens of this vole were taken at Skagway, Glacier, Bennett, 

 Lake Marsh, Lake Lebarge, Rink Rapids, and near Charlie Village. 

 Specimens from near the coast are almost exactly like those of the inte- 

 rior and all are quite typical of the species. They were found in various 

 environments, but the general habitat of the species was dry places 

 rather than moist. At Glacier and Bennett they were secured on dry, 

 rocky hillsides; at Lake Marsh two specimens were taken in the crev- 

 ises of some granite rocks; at Lake Lebarge they were taken in the 

 kitchen of a log cabin; at Rink Rapids, in an open, sandy place; and 

 near Charlie Village, on the side of a cut bank, where they had made 

 burrows and runways among the exposed roots of trees. Charlie 

 Village is by far the northernmost locality from which the species has 

 been recorded. 



Microtus drummondi (Aud. and Bach.). Drummond Vole. 



This is the most common meadow vole of the Yukon region. At 

 Caribou Crossing and Lake Marsh its runways form interminable 

 labyrinths in the level, open stretches of sedge at the margin of the 

 water. It occurs in nearly all moist, grassy places from Caribou 

 Crossing to Fort Yukon. From there it undoubtedly ranges farther 

 on, at least to Nulato, where Dali took several specimens. It is most 

 active during the day, as I easily learned by visiting traps night and 



^ No good series of specimens is available from any point nearer Finlayson Eiver, 

 the type locality of E. dawsoni, than Rink Rapids. This series is therefore used to 

 represent the species. 



