156 MICROTIN^ 



Range. — This species inhabits the maritime districts of northern 

 and eastern Greenland, ranging from about Cape Dalton on the 

 east coast in lat. 69° N., northwards to the limit of land (Mary- 

 Murray and Lockwood Islands in lat. 83° N.), and thence west- 

 wards along the northern coast to the Kane Basin and Robeson 

 Channel, and southwards to the margin of the Humboldt Glacier. 

 It also inhabits the countries westwards of Robeson Channel, 

 ranging from about 83° N. lat. southwards through Grant Land, 

 Grinnell Land, Ellesmere Land and Baffin Land, reaching its 

 southern limits at Cape Mercy in the Cumberland Peninsula and 

 on the northern shore of Hudson's Straits. Its western limits of 

 range are imperfectly known, but it probably extends to the 

 eastern shore of the Gulf of Boothia in Cockburn Land and the 

 Melville Peninsula ; for some of the specimens obtained by 

 Dr. Rae, in 1847, during his expedition to the region north of 

 Repulse Bay appear to belong to this species and not to 

 D. ruhricatus. 



Characters. — A rather small species (hind-foot to 16-5 mm. ; 

 condylo-basal length of skull to 29-6 mm.). Skull and teeth 

 essentially as in D. torquatus ; but rostrum slender and upper 

 incisors weak and somewhat straightened. Adults in summer 

 with grey upper parts resembling D. hudsonius in appearance; 

 spinal stripe represented only by a dusky streak on top of the 

 head. Essential characters as in other members of the genus, 

 but hind-foot unusually short, varying between 13 and 16-5 mm. 

 in six adults from Discovery Bay. 



Colour of adults in summer pelage. — Upper parts with a fine 

 grizzle of grey, black and ochraceous the general effect approaching 

 the '"mouse-gray" of Ridgway; more or less brightened by 

 ochraceous at the ears, on the nape, shoulders, rump, and on 

 the flanks. The prevailing grey colour is produced by hairs 

 which have their middle thirds white, very narrow subterminal 

 ochraceous bands, and dusky tips. The colour is locally bright- 

 ened by broadening of the subterminal ochraceous bands and at 

 the ear-tufts by the entire elimination of dusky tips. Spinal 

 stripe almost obsolete ; usually represented only by a dark 

 streak between the nose and the withers, but in one specimen (i 

 from Discovery Bay traceable as a narrow ill-defined streak from 

 the rostrum almost to the rump. Under parts washed with 

 ochraceous-orange. Tail and feet white or cream-coloured. 



Skull rather small and lightly built, with the rostrum slender. 

 Parietals articulating with the supraoccipital. Auditory bullse 

 rather large and anteriorly inflated. 



Dentition. — Upper incisors weak, noticeably narrower than in 

 D. ruhricatus, less strongly curved and somewhat protruding 

 (" proodont "). Cheek-teeth essentially as in D. torquatus, but 

 rather light ; postero-internal vestigial angles in m^ and nfi 

 present, but usually weakly developed ; ni^ lacking an antero- 

 external vestigial angle. 



