202 MICEOTIN^ 



behind the shoulders, produced by a concentration of the black 

 hairs along the spine ; in some individuals more or less definite 

 traces of this stripe can be seen between the withers and the 

 rump. On each side of the head a faint blackish streak extends 

 backwards from the muzzle, through the eye to the ear, where it 

 often broadens out to form a rather conspicuous pre-auricular 

 blackish patch. Flanks, including the upper hps and sides of 

 face and neck, and under surface yellow or whitish; yellower 

 and clearer laterally at the junction with the dark dorsal colour. 

 Belly darkened irregularly by the slaty bases of the hairs. Hands, 

 feet, and tail light brown above, paler, bufEy white, below and 

 at the sides. 



Winter pelage : — According to Middendorfi (Sibir. Reise, 2, 

 Th. 2, p. 101) the winter coat, in Taimyrland in lat. 71° N., begins 

 to appear about the middle of September and is completed by 

 the end of October. Fur thicker and more silky than in summer. 

 Colour paler reddish-yellow, less intensely orange, above and 

 without trace of a median black stripe either on the head or on 

 the back. Palms and soles more densely haired than in summer. 



Young have much shorter, darker and duller coats than 

 adults ; dull blackish-brown, very lightly tinged with reddish- 

 yellow above, the black dorsal stripe more or less evident; 

 mouse-grey below. The young assume the adult summer pelage 

 very early in life ; and Middendorff observed it in one with a 

 total length of only 82 mm. 



Skidl and teeth essentially as in L. lemmus ; the cheek-teeth, 

 however, in individuals of equal age, rather larger and heavier 

 than in the latter species. 



For external and cranial dimensions, see tables at end of 

 volume. 



Remarks. — Middendorff {oj). cit., p. 104), observed a great 

 disproportion in the numerical representation of the sexes in 

 Taimyrland, adult males apparently outnumbering the females 

 by twenty-five to one, and among the nesthngs males were far 

 more numerous than the females. A good account of this Lem- 

 ming and its habits in Waigatsch and Novaya Zemlya is given 

 by Heuglin (Reisen n. d. Nordpolarmeer, 3, p. 16, 1874). , 



26. Lemmus obensis novosibiricus Vinogradov. 

 1924. Lemmus ohensis novosihiricus Vinogradov, Ann. Mag. N.H., 

 [9], 14, p. 187. 



Co-types. — Zool. Mus. Russ. Acad. Sci. (Leningrad) ; ten 

 specimens (skins and skulls, and a skeleton) collected by the 

 Russian Arctic Expedition 1901-1902, the Yana Expedition of 

 Toll and Bunge, and the Hydrographic Expedition to the 

 Northern Ocean 1912. 



Type locality. — " Kotelmy and Liakhov Islands, New Siberian 

 Archipelago, N.E. Siberia." 



