1908.] MAMMALS. 175 



White-footed mice inhabit nearly all kinds of ground, from swamps 

 to high, dry situations, though the latter constitute the favorite 

 habitat, especially if ledges of rock occur. They are always common 

 about the buildings at trading posts, especially during the wintei 

 season, taking the place of the house mouse of more southern regions, 

 and becoming quite as much of a pest. The traveler while camping 

 often hears them as they search for food about his tent at night, 

 making their presence known in the dry leaves about his bed, or by 

 attempts to climb the walls of the tent. 



While on my trip northward from Fort Rae in August, 1903, I 

 took specimens on Grandin River about 50 miles north of Fort Rae, 

 but failed to detect the species to the northward of that point, though 

 considerable trapping was done. It was next seen at Fort Norman, 

 on the Mackenzie, where it is a common species. It is common also 

 along the Mackenzie above Fort Norman, and as we ascended the 

 river during October we frequently saw its characteristic footmarks 

 on the freshly fallen snow. At Fort Simpson I found it abundant 

 and active all winter, and collected many specimens both in the woods 

 and about the buildings. A nest of young was found in one of the 

 houses on April 20, 1004. The Indians say that the animal has three 

 litters during the summer. The number of embryos noted in the 

 Slave River region during June, 1901, varied from four to eight. In 

 1904 I noted seven small embryos in a specimen taken at Fort Simp- 

 son, on April 12, and the same number at Fort Norman, June 15. I 

 did not detect the species on the Mackenzie below Fort Norman. 



Richardson refers to the species under the name Mus l<'n<-<>/mx. and 

 states that it was observed as far north as Great Bear Lake." King 

 found it abundant in the winter of 1833-34 at Fort Reliance. Great 

 Slave Lake, where it established itself in the dwelling house a short 

 time after the building was completed.'' Cones records specimens 

 from Fort Resolution, Fort Rae. Big Island, Fort Simpson, and Fort 

 Liard. 6 ' Ross records specimens from several localities, including 

 Fort Good Hope. The species may have been introduced at the last- 

 named post, but it is rather doubtful if it occurs there naturally. 

 Allen has recently recorded specimens taken by Stone at Hell Gate 

 (Liard River), Fort Liard. and Fort Norman/' 



In September, 1894. J. Alden Loring found this mouse common at 

 Edmonton, Alberta, and took a large series. Ten adults average: 

 Total length 163.2, tail vertebrae 75.9. hind foot 20. lie took the 

 species also at St. Albert, northwest of Edmonton, in 1 s<»r>. During 



"Fauna Boreali-Americana, I. p. 111!. 1sl".». 



6 Narrative Journey t<» Arctic Ocean, I. p. w>r K L836. 



'■ Monographs X. A. Rodentia, p. 84, L877. 



*Bull. Am. Mus. Nat. Hist., XIX, p. 542, 1003. 



