1008.] MAMMALS. 181 



T first collected this vole at Trout Rock, 25 miles south of Fort 

 Rae, early in July. L901, and a few days Later took a small series 

 at Fort Rae. In L903 I found it common along my route between 

 Great Slave and Great Bear lakes, and took specimens at several 

 places. I took a small series also on the south shore of Great Bear 

 Lake near Leith Point, where T found the animals living among the 

 rocks on the semibarren tracts near the shore and feeding largely on 

 the crowberries {Empetrum nigrum). At Fort Franklin the species 

 was very common in spruce woods, and a lame series was procured. 

 It was not very common at Fort Simpson, but a fair series in winter 

 pelage was taken. This pelage is characterized, in comparison with 

 the summer coat, by lighter color, and l>y longer fur. the tail espe- 

 cially being much more heavily clothed. During my trip down the 

 Mackenzie in June. 1004. 1 took specimens at Forts Norman, Good 

 Hope, and McPherson, as mentioned above. 



An adult male taken at Fort Good Hope, June 23, furnishes the only 

 instance of dichroinatism in this species that I have seen. It is in 

 the light phase of coloration. The dorsal stripe is yellowish In-own. 

 only slightly different from the sides anteriorly, but becoming darker 

 toward the rump. The red element so conspicuous in the color of the 

 dorsal stripe in normal specimens is practically absent. Specimens 

 from Fort Liard and Fort Anderson, in the collection of the National 

 Museum, have been examined and prove referable to this species. 

 Specimens from these localities, as well as from Fort Rae. Fort 

 Norman. Fort Good Hope, and La Pierre House were recorded, under 

 the name E. rutilus, by Coues. Allen has recently recorded E. daw- 

 soni from TTell Gate (Liard River), Fort Liard, and Fort Norman.'' 



Lemmus trimucronatus (Richardson). Back Lemming. 



This species was described by Richardson from a specimen taken 

 by Captain Back on tin* shores of Point Lake.'' During Franklin's 

 second expedition additional specimens were taken on Great Bear 

 Lake, and the measurements of one from Fort Franklin are given by 

 Richardson.** The animal was met with near the head of Back 

 River, during Pack's journey down that stream, and is recorded by 

 King. 6 Coues. under the name Myodes obensis, records specimens 

 from Fort Ajiderson : Anderson River; ' Arctic coast : ' and Peel River, 

 those from the last locality taken by C. P. Gaudet. the others by 

 MacFarlane.' A few specimens from Fori Anderson are still in 

 the National Museum, but are too imperfect for satisfactory com- 



"Mnuni.Mai.hs N. A. Rodentia, p. 139, 1877. 



'T.ull. Am. Mas. Nat. Hist., XIX. p. -",17. 1903. 



r Appendix Parry's Second Voyage, p. 309, 1825 (1827), 



''Fauna Boreal i-Americana, I. pp. 130, 131, 1829. 



e Narrative Journey to Arctic Ocean, I. p. 250, 1836. 



f Monographs N, A. Rodentia, p. 243, 1877. 



