180 CALIFORNIA MAMMALS. 



Suborder Duplicidentata. 



Three pairs of upper incisors, one pair being lost soon after 

 the animals birth ; enamel covering the sides as well as the front 

 of the incisors ; incisive foramina large and usually confluent ; 

 bony palate very narrow from front to back. 



Family Ochotonidae. Pikas. 



Adult incisors two below and four above, ther extra pair very 

 small and hidden behind the others, which are deeply grooved in 

 front; molars rootless; five toes on each front foot and four on 

 hind foot ; no visible tail ; ears of moderate size, broad, rounded ; 

 eyes small; hind legs not greatly longer than the fore legs; size 

 small. 



This small family of one genus and fifteen or more living 

 species inhabits alpine and boreal parts of Asia and North Amer- 

 ica. The species are all small in size and similar in habits. The 

 food is grass and other herbage, the leaves and twigs of alpine 

 shrubs, and probably some seeds. Food is stored in autumn for 

 winter use, and it is probable that Pikas do not hibernate, although 

 living where the snowfall is heavy. They are social ; digitigrade ; 

 partly subterranean and principally diurnal. There is some varia- 

 tion in color, this being apparently due to environment and pro- 

 tective. The sexes are alike and the young but little different. 



Genus Ochotona Link. (Mongol name for the Pika.) 



Occiput not depressed; a process of the molar is prolonged 

 almost to the ear; aduitory bull?e large; angular process of lower 

 jaw small, pointed, recurved ; condylar process high, greatly flat- 

 tened, wide antero-posteriorily ; coronoid process minute, with a 

 supplementary tubercle just back of the last molar; soles densely 

 haired except a prominent pad at the base of each toe ; pelage 

 thick, long, coarse. 



Dental formula, I, 2 — i ; C, o — o; P, 2 — 2 ; M, 3 — 3X2=26. 



