Mammals of the 1921 Mount Everest Expedition. 185 
brilliant red by August. Under surface the usual mixed 
greyish colour, the bases of the hairs blackish slaty, their tips 
whitish, Middle 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. ars 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 buffy 
suffusion, extending up more or less on to the nape, and so 
forming a prominent greyish collar. <A little buffy com- 
monly 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 royle?. 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 roylez. Frontals in all the specimens 
fenestrated, but this is a variable character in other species. 
Bullz as in roylei, not as in macrotis. —* 
Dimensions of the type (measured in flesh) :— 
Head and body 184 mm. ;: hind foot 30 ; ear 36. 
Skull: greatest length 45; condylo-incisive length 41:5; 
zygomatic breadth 22°5; nasals 16x5°5; _ interorbital 
breadth 5°5 ; breadth across brain-case above meatus 18°5 ; 
palatal foramina 13°3 ; width of palatal bridge 1:5; antero- 
posterior length of bulla 10. Upper tooth-series (alveoli) 8°2. 
Hab. 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 O. roylez, 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, O. roylet 
has a warmer tone on the rump than on the 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 O. wollastont. It is, however, possible that 
forms connecting it with roylei on the west, or chinensis on 
the east, will yet be found, in which case a trinomial will 
have to be used for it. 
This Pika, on whose discovery Mr. Wollaston is to be 
congratulated, appears to be the mammal which hag its 
