492 



RODENTIA 



Guinea-Pig-like animals, inhabiting chiefly the mountainous parts of 

 Northern Asia (from 11,000 to 14,000 feet), one species only being 

 known from South -East Europe, and another from the Rocky 

 Mountains. 



The Picas, or Tailless Hares, live in holes among the rocks of 

 their native mountains, and are agile and shy little creatures. 

 The genus is well represented through the upper and middle 

 Tertiaries. It has been proposed to separate those fossil forms 

 with p f as Myolagus, and those with p \ as Titanomys, but this 

 seems scarcely advisable. 



Family LEPORID^E. 



Imperfect clavicles, elongated hind limbs, short recurved tail, 



and long ears. Skull 

 (Fig. 216) com- 

 pressed, frontals 

 with large wing- 

 shaped post -orbital 

 processes p f ; molars 

 as in the Lagomyidcp. 

 Cosmopolitan (ex- 

 cept Australasia). 

 Vertebrae: C 7, D 

 12, L 7, S 4, C 13- 

 15. 



Lepus. 1 The 

 single genus Lepus 

 includes about 

 twenty species, all 

 of which resemble 

 one another in 

 general external characters. In all the fore limbs have five and 

 the hind only four digits, and the soles of the feet are densely 

 clothed with hairs similar to those covering the legs ; the inner 

 surface of the cheeks is also hairy. Although the family has such 

 a wide distribution, the greater number of the species are restricted 

 to the Palsearctic and Nearctic regions, only a single species (L. 

 brasiliensis) extending into South America, where it has existed 

 since the date of the Pleistocene deposits of the Brazilian caves. 



The Common Hare (L. timidus 2 ) may be taken as a typical 

 example of the genus, and is characterised by the great length of 



1 Linn. Syst. Nat. 12th ed. vol. i. p. 77 (1766). 



2 From the absence of the Common Hare in Scandinavia it is considered 

 probable that the name L. timidus was really applied to the Mountain Hare, 

 and some writers accordingly use the name L. europceus for the former. 



FIG. 216. Skull of Hare (Lepus timidus). 



