152 MICROTIN^ 



1901. Dicrostonyx hudsonius nelsoni EUiot, Field Columbian Mus. 



Publ., Zool. Ser. 2, p. 210, fig. 48. 

 1905. Dicrostonyx richardsoni Macfarlane, Proc. U.S. Nat. Mus., 28, 



p. 736. Not of Merriam. 

 1919. Dicrostonyx ruhricatus G. M. Allen, Bull. Mus. Comp. Zool., 



Harvard Coll., Cambridge, 62, p. 518. 

 1914; Dicrostonyx ruhricatus rubricatus Miller, " List," 1924, p. 397.^ U 



Type. — Unknown ; none specified, the description based upon 

 Collie's notes. 



Type locality. — Shore of Behring Strait, Alaska. 



Range. — Alaskan peninsula and coastal islands, eastwards 

 in the neighbourhood of the Arctic coast of Mackenzie to Corona- 

 tion Gulf. 



Characters. — Closely resembling the Old World D. torquatus 

 torquatus in all essential respects; but adults in summer pelage 

 rather more brilliantly coloured and with a somewhat indistinct 

 black spinal stripe extending from the nose to the tail. 



Colour of adults in summer. — " Sides of the muzzle and an 

 area about the eyes gray, due to a mixture of short hairs, some 

 whitish, others black-tipped. Forehead from nose to the nape, 

 black, sometimes grizzled with a few gray hairs. This mark is j 

 continued as a narrow black median stripe to the root of the tail. 

 Ears marked by a tuft of rusty hairs. Shoulders nearly clear i 

 chestnut, about morocco-red of Ridgway (1912) mixed with i 

 whitish, this colour extending back along the sides of the thorax, 

 and blending dorsally with the grizzled whitish and blackish of , 

 the back; hips grayish. Lower surfaces usually washed with j 

 orange buff, but in some specimens whitish. Tail and feet ' 

 whitish " (G. M. AUen, 1919, p. 519). 



Young in first pelage resemble advdts in summer coat, but lack 

 the brilliant colours of the adults ; general colour of upper parts 

 uniform cinnamon buff, with black dorsal stripe from the forehead 

 to the tail. Ear-tufts black. A clear tawny patch at the 

 shoulder. Sides and under surface washed with ochraceous buff. 



Skull. — Closely resembling that of D. torquatus; differing ; 

 from that of D. hudsonius in the relatively shorter nasals and ' 

 slightly more squarely spreading zygomatic arches. Interparietal 

 separated laterally from the squamosal on each side by a narrow 

 tongue sent backwards by the parietal to articulate with the 

 supra-occipital. 



Cheek-teeth. — Essentially as in D. torquatus ; a postero-internal 

 vestigial angle constantly present in tn^ and m^. 



For external and cranial measurements, see tables at end of 

 volume. 



Remarks. — Mr. G. M. Allen deserves great credit for identifying 



the Alaskan Collared Lemming with Richardson's " Arvicola 



ruhricatus." Richardson's brief diagnosis, based upon Surgeon 



Collie's manuscript notes of a mouse that " burrows in the turfy 



* See footnote on p. 161. 



