306 MICROTIN^ 



the food supply, they probably influence the dentition and the 

 correlated cranial characters; but their control in this direction 

 is less peremptory and direct; for what food shall be available 

 to Alticola in any given district must obviously depend upon the 

 presence or absence there of competing genera as well as upon 

 the physical conditions of the station. 



Key to species and subspecies of Alticola : — • 



A. »ft' in adults with at least three well-developed salient angles 

 on the inner side. Tail always longer than hind-foot. 

 Palms and soles naked between pads, more or less densely 

 haired posteriorly. 

 a. Tail imperfectly clothed, its scaly annulations more or less 

 apparent. Claws not hidden by long dorsal hairs of 

 digits. 

 «!. Tail very long (54% of head and body length), wholly 

 white, with a thin terminal pencil of about 7 mm. in 

 length. Colour very pale, ecru drab above, white 

 below; m^ with third triangle closed behind. 



A . argunis Thomas. 

 Hissar Mts. (9500 feet). 

 b^. Tail shorter, not exceeding half the length of the head and 

 body; distinctly bicoloured in all except A. albicauda. 

 Colour darker, 

 a^. Skull long, narrow and dehcately built ; m^ with third 

 outer fold well developed, the third triangle sub- 

 stantially closed behind. Tail long (40-50% of head 

 and body length), with a long but thin terminal 



pencil A. blanfordi Scully. 



a^. Colour darker, yellowish-brown above, whitish or 

 faintly buffy below. Auditory bullae smaller; 

 m^ with a distinct though small fourth outer angle. 



A . blanfordi lahulius Hinton. 

 Lahul (10,000-14,000 feet). 

 &'. Colour paler, light greyish-brown above, greyish- 

 wliite below. Auditory buUse larger; m? with the 

 fourth outer angle vestigial. 



A. blanfordi blanfordi Scully. 

 Gilgit (9000-10,000 feet). 

 6^. Skull broader and more heavily built. 



a^. m' with third triangle substantially closed behind. 

 Auditory bullae larger; cheek-teeth lighter. 

 a*. Tail longer (about 40% of head and body length), 

 its terminal pencU very short. Colour darker; 

 dark gre3ash-brown above, silvery-grey below. 



A. montosa. True. 

 Central Kashmir (11,000 feet). 

 6*. Tail shorter (about 35% of head and body length). 

 Colour lighter; hght brownish -grey above, 



greyish- wMte below A. glacialis IMiller. 



Baltistan (11,000 feet). 

 &'. m^ with third outer infold reduced, the third triangle 

 more or less confluent with the posterior loop. 

 a*. TaU longer (averaging 33-36% of the head and 

 body length), distinctly bicoloured; its terminal 



