148 MICROTIN^ 



1. Dicrostonyx torquatus Pallas. 

 (Synonymy under the subspecies.) 



Range. — Arctic regions of the Old World from the eastern 

 shore of the White Sea through Russia and boreal Asia ; eastward 

 limits of range unknown. Inhabiting Spitzbergen, Novaya 

 Zemlya, and the New Siberian Islands. Not ranging south of 

 lat. 68° N. 



Characters. — Size medium ; head and body about 130 mm. ; 

 hind-foot 20; condylo-basal length of skull 30. Essential 

 external characters as described under the genus. 



Colour, in summer, brown or grey above according to the 

 subspecies ; the brown or typical form without a spinal stripe ; 

 the grey form {D. t. ungulatus) with a definite dorsal stripe. 



Skull normal, but available material not sufficient to enable 

 us to appreciate specific peculiarities. Upper incisors moderately 

 heavy and much more strongly curved than in D. groenlandicus 

 (" orthodont " instead of " proodont ") ; those of D. ruhricatus 

 being apparently intermediate. Cheek-teeth of the more complex 

 type; m} and m"^ usually with postero-internal vestigial angles, 

 but these are sometimes absent (Fig. 71, i); hinder wall of the 

 postero-internal triangle in each of the two teeth named retaining 

 its thick enamel and usually its concave shape. 



Remarks. — The material before me is totally inadequate for 

 the purpose of determining the characters of this species and its 

 relationship to the American D. ruhricatus. 



la. Dicrostonyx torquatus torquatus Pallas. 



1779. Mus torquatus Pallas, Nov. Spec. Quadr. Glirium Ord., pp. 77, 

 205, taf. xi, B. 



1779. Mus lenensis Pallas, Nov. Spec. Quadr. Gilr. Ord., p. 199. 



1808. Spalax torquatus Tiedemann, Zoologie, 1, p. 47. 



1811. My odes torquatus Pallas, Zoogr. Rosso-Asiat., 1, p. 173 ; Midden- 

 dorfif, Sibir. Reise, 2, Th. 2, p. 87, 1853. 



1817. Arvicola (Georychvs) torquatus Cuvier, Regne Anim., 1, p. 207. 



1820. Lemmus torquatus Desmarest, Mammalogie, p. 289. 



1827. Hipudceiis torquatus Lesson, Man. Mamm., p. 277. 



1829. HypudcBus torquatus Fischer, Synopsis Mamm., p. 298 (mis- 

 quoting Lesson). 



1844. Myodes hudsonius Middendorff, Bull. CI. physmath. Acad. 

 Imp. Sci. St. Petersburg, 3, p. 291. Not of Pallas, 1779. 



1874. Cuniculus hudsonius Coues, Proc. Acad. Nat. Sci. Philadelphia, 

 p. 196 (part). 



1877. Cuniculus torquatus Coues, Monogr. N. Amer. Rodentia, 

 Muridse, p. 246 (part). 



1896. Dicrostonyx torquatus Miller, N. Amer. Fauna, No. 12, pp. 38-40 

 (part). 



1922.t Dicrostonyx torquatus altaicus Vinogradov, Ann. Mus. Zool. 

 Acad. Sc. Russ., 23, p. 372; Co-types :— High Mining School 

 Collection, No. 248/11 A. Leningrad (Gtorny Institute); seven 

 left and five right mandibular rami; described from the Caverns 

 of Tsharysch and Khankara Rivers, N. W. Altai, 180 kilometres 

 from Bijsk. 



