Mammals of the 1921 Mount Everest Expedition. 185 



brilliant ii'cl by August. Uu'lcr suifnce the usual mixed 

 greyish colour, the bases of the hairs blackish slaty, theii tips 

 whitish. Micldle area of face more or less fulvous, succeeded 

 behind on the crown by grey, about like that of the back, but 

 when in worn pelage this part often looks nearly black. Sides 

 of face grey. Eiirs large, their hairs white internally, blackish 

 externally, a narrow line along the edge white. A large 

 area behind each ear greyish white, sometimes with a butfy 

 sutl'usion, extending up more or less on to the nape, and so 

 foiming a prominent greyish collar. A little buffy com- 

 moidy present, running along the boundary between the 

 upper and lower colours from the muzzle to the level of the 

 elbows. Rump grey like the rest of the back, not of a 

 warmer tone as it generally is in roylei. Anal area incon- 

 spicuously white. Hands and feet greyish white without 

 tendency to bufFy, a little darker grey on the middle of the 

 metapodials. 



Skull essentially as in roylei. Frontals in all the specimens 

 fenestrated, but this is a variable character in other species. 

 Bullie as in roylei, not as in macroiis. 



Dimensions of the type (measured in flesh) : — 

 Head and body 184 mm. ; hind foot 30 ; ear 3G. 

 Skull: greatest length 45; condylo-incisive length 41-5: 

 zygomatic breadth 22-5 ; nasals 16 x 5"5 ; interorbital 

 breadth 5"5 ; breadth across brain-case above meatus 18*5 ; 

 palatal foramina 13*3 j width of palatal bridge 1*5; antero- 

 posterior length of buliie 10. Upper tooth-series (alveoli) 8"2. 

 Bab. Mt. Everest, at altitudes from 14,500' to 20,100'. 

 Type from 17,500'. 



Type. Adult female. Original number 54. Collected 

 12th September, 1921. Thirteen specimens. 



This species, while no doubt by its general characters and 

 "size of skull nearly allied to 0. roylei, is yet clearly distinct 

 by the complete absence of the brilliantly contrasted rufous 

 mantle on the head and fore-quarters which comes on in that 

 species during the late summer. And even in the early 

 summer, before the rufous has begun to appear, 0. roylei 

 has a warmer tone on the rump than on tlie middle back, 

 which is not the case here, and the feet have always 

 some tone of yellowish or brownish as compared with the 

 white feet of 0. wollastoni. It is, however, possible that 

 forms coimecting it with roylei on the west, or cJdnensis on 

 the east, will yet be found, in which case a trinomial will 

 have to be used for it. 



Tills Pika, on whose discovery Mr. Wollaston is to be 

 congratulated, appears to be the mammal which has its 



