OcTOEEK,1902.] MAMMALS OF KEEWATIN". 57 



fruitful collecting grounds. At my two camps on the Barren Grounds 

 south of Cape Eskimo the_v were abundant in their favorite locations; 

 and on a long sand}' ridge below Cape Churchill, where we landed on 

 the afternoon of August 2-i, we found many burrows and captured 

 about 20 lemmings. Onlj- one was actuallj' seen away from its bur- 

 row — a female which, when surprised by us some distance from her 

 home, ran into a shallow deserted burrow for refuge. The animals 

 seem mainly nocturnal in their habits, though a few wei-e taken at the 

 mouths of holes during the daytime. The}' are known b}' the natives 

 of Churchill as ' Husky ' or ' Huckey ' (i. e. , Eskimo) mice, because of 

 their northern habitat. 



Compared with skulls ot DiG7'ostonyx hiidwiu'us from the coast of 

 Labrador, those of D. richardsojn exhibit the following conspicuous 

 differences: Braincase broader; interparietal broader and squarish in 

 outline (in Jnnhonhix small and triangular); parietals broader; bulla? 

 much more inflated. 



In color D. ric]iardso)ri is much darker than hndsonius, owing to a 

 much greater proportion of chestnut- and brown-tipped hairs in the 

 pelage. The specimens taken by us vary remarkably, but the gra3'est 

 show more brown than any specimens of Jmdsoniuf< examined. 



Topotypes of D. 7'ichardsoni in summer pelage ma}' be described 

 as follows: Fur light plumbeous at base; that of back and sides 

 tipped with chestnut or rich yellowish brown, occasionally with these 

 colors and gray, sides usually lighter than back. A dusky stripe, 

 rarely continuous but usually interrupted on face, extending from 

 nose to tail; this stripe nearly obsolete in some very old specimens, 

 but very distinct in young, and in some about half grown more than 

 5 mm. in width. Orifice of ears surrounded by black hairs tipped 

 with chestnut. Lower parts varying from yellowish white to rich 

 yellowish brown, variation according with the richness of color of 

 upperparts; throat and chest always darker than rest of lower parts.' 

 Soles and forelegs lighter than rest of lower parts, usually nearly 

 white; tail usually unicolor, yellowish white, but sometimes dusky 

 above; pencil yellowish white. 



The young vary but little in color. Those perhaps a week old 

 are grayish brown above, with the very distinct dusky dorsal stripe; 

 beneath practically naked, but with a trace of white down. Others a 

 little older are grayish brown above, varying a little even in the 

 same litter, in the same way as the adults, but in a less degree; 

 beneath yellowish white, brownish between forelegs. Young half 

 grown and larger resemble adults, but are generally grayer, and never 

 show the extreme richness of coloring exhibited by adults. 



Measurements. — Average of 10 adults: Total length 139.5; tail ver- 

 tebrae 17.8; hind foot 18.4. Oneof the largest specimens: Total length 

 150; tail vertebrae 20; hind foot 20. Average of 8 adult skulls: Basal 



