DOGS 25 



native races. There are also wild dogs in India^ but 

 the generally received opinion is that the various 

 breeds of domestic dogs have descended from the 

 wolf and the jackal, man having gradually evolved 

 them by taming various species, and through 

 thousands of years selecting those to breed from 

 which he found most tractable and useful to him. 



Fig. 9. — Dog's Skull. (Photo, by H. C. Wood, from a specimen 

 in the British Mnsenm of Natural History.) 



The dog may be easily distinguished from the cat 

 by having a longer muzzle and more teeth, which 

 are not so sharp as the cat's. He has the same 

 number of toes and fingers placed in the same posi- 

 tion, but the claws are not hooked and he has no 

 power of withdrawing them. The skin of the pads 

 is thicker and harder and the tongue is smooth. The 

 limbs are harder and more bony, and the body 



