208 Mammals of Eastern Asia 
sea level. Their fossil remains are found in England, France, 
and Germany. 
Certain of the Asiatic Pikas excavate burrows; others, in- 
cluding those of North America, live in natural crevices among 
rocks, where their little mounds of cut vegetation or "hay" are 
often almost the only indication of their presence in the region. 
Various classifications of the Pikas have been proposed, al- 
most all based upon the form of the openings in the front of the 
bony palate of the skull. For our purposes two divisions are 
easily recognized: the first with the two openings very long, 
typical of Ochotona proper; the second with the openings short 
and coalescing to make a single more or less oval hole in the 
palate, indicative of the subgenus Pika. External characters are 
not very helpful in deciding to which of these two subgenera a 
given kind of Pika belongs. 
The subgenus Ochotona, which is the typical part of the genus 
Ochotona, extends from the Altai Mountains in central Siberia 
south through Mongolia, Kansu, and Shansi into Tibet and the 
Himalaya Mountains. The Dahurian Pika, Ochotona dahurica, 
of Mongolia may be considered the type species. Allied forms 
within the geographical scope of the present work are 0. thi- 
betana forresti from the Likiang Ranges in southwestern Yun- 
nan; 0. t. osgoodi from northeastern Burma, 8000 to 9000 
feet; O. cansa and O. c. stevensi, both from Szechwan. 
Certain allied species, which are separated by some writers 
under the subgeneric term Ogotoma, typified by O. pallasii of 
Mongolia, have a central Asiatic pattern of distribution. They 
are represented in Ladak in the Himalayas at very high altitudes 
by O. ladacensis. These are larger animals with proportionately 
larger ears and feet. The color of ladacensis is light brownish 
gray, with reddish on the head, the underparts yellowish white. 
The length of the head and body is 9 inches, of the ear 1% 
inches, of the foot almost V/o inches. The species is found 
from 14,000 to 18,000 feet in the Himalayas. 
