92 A COURSE ON ZOOLOGY. 



latter which carry the nails or claws are raised in such 

 a manner that the claws are held above the ground and 

 are not too rapidly worn away. 



The bones of the limbs are long ; the muscles, thick 

 and strong on the shoulders and haunches, terminate in 

 hard, dry tendons ; the articulations are very flexible, 

 and allow a great extension of the four limbs. The pos- 

 sible vigor of projection of the body in running and 

 jumping is sufficiently indicated by the great fleshy 

 development of the hind-quarters. 



The feet are provided with strong nails or claws, 

 slightly curved, and affording great aid in climbing steep 

 and slippery hills. Under each digit is a sort of pad, 

 rough, strong, and elastic, and a clover-leaf shaped pad 

 of the same nature is placed under the palm. By these 

 protecting pads, that come directly in contact with the 

 ground, the digits are removed from the ordinary causes 

 of hurts and irritations. There is between the digits a 

 fold of skin, somewhat like the web-foot of a duck ; this is 

 quite rudimentary in most dogs, but is largely developed 

 in the Newfoundland and the spaniel, and explains the 

 great facility with which these dogs can swim. Most 

 dogs are capable of swimming for a long time. 



The body of the dog is slender in the region of the 

 belly, but much enlarged in the chest, indicating easy 

 and deep respiration. It is light, relatively to the 

 strength of its limbs ; and because these latter have but 

 a slight weight to support, they do not quickly become 

 fatigued, and the animal is able to run a long time 

 without losing breath or requiring rest. 



All animals that hunt game must have an accurate 

 vision, and another gift, perhaps still more important, a 

 delicate sense of smell. Now, the dog has excellent sight, 



