SPECIES OF MAMMALS OF THE PACIFIC AREA 123 



Fig. 51 — Brush-Tailed Porcupine 



Rabbits and Their Allies. Order Lagomorpha 



The rabbit family and the related group which contains the 

 mouse-hares or pikas, resemble the rodents by having a large 

 space between the incisors and the cheek-teeth and by having a 

 single pair of lower and one functional pair of upper incisors. 

 A second small pair of incisors is present behind the functional 

 upper pair. The enamel is not confined to the front of the in- 

 cisors, as in the rodents. The lower jaw moves from side to side 

 in chewing, rather than back and forth, and there are also many 

 internal differences between the rabbits and the true rodents. 



The members of the rabbit family are much alike ; they differ 

 chiefly in size, length of ear, and precise pattern of the teeth. 

 The tail varies in size and conspicuousness, but it is always 

 visible. The pikas or mouse-hares have ears that project only 

 slightly above the top of the head, and their hind feet and legs 

 are not more elongated than those of squirrels ; the tail is not 

 visible externally. 



