466 MAMMALIA. 



projecting norny papillae. The fore-feet have five, the hind 

 four toes, armed with claws, which are retractile. When not 

 in use these claws (fig. 221, a) are drawn back by means of 

 ligaments (a and h) into sheaths (.s-), so as not to be unneces- 

 sarily worn down. All the Felidae are extremely active, and 

 have a very flexible backbone. They are mainly nocturnal 



3 



,•' f> 



Fio. 221. — Bones of Toe of Cat— a, with retracted, b, with extended claw. 



a, Tendon of extensor muscle ; h, retractor ligament ; mc, metacarpal ; pit (1, 2, and 

 3), 1st to 3rd phalanges; s, bony sheath into which claw lits. (From Brit. Mus. 

 Cut.) 



in habits, catching their prey by springing upon it ; many of 

 the lighter-built Felidse climb well. 



One wild species occurs in Britain, but only in the north, 

 especially Scotland — namely, the Wild Cat (Felis catns). The 

 domestic cat is descended from the Nubian Cat (F. maniculata), 

 a native of the Soudan and Nubia. 



Order RODENTIA or GNAWERS.^ 



The order Rodentia contains the Mice, Rats, Squirrels, Rab- 

 bits, and Hares. These are sometimes called " Glires.'' The 



' The Rodentia are now placed in the order Trogontia of Haeckel ; the 

 two other sub-orders are the TUlodontia and Typotheria, formed for cer- 

 tain Tertiary species. 



