MAMMIPEROUS ANIMALS. 2^ 



feet, wlilch are usually divided at the extremities 

 into toes or fingers. The extremities, however, of 

 some, as the Horse, end in a single corneous substance, 

 called a hoof. The toes of a few of the quadru- 

 peds end in broad flat nails, and of most of the others 

 in pointed claws. Sometimes the toes are connected 

 together by a membrane : this is the case in animals 

 that spend part of their lives in the water. Some- 

 times, as in the Bats^ the digitations of the anterior 

 feet are greatly elongated^ having their intervening, 

 space filled by a membrane which extends round the 

 liinder legs and the tail, and by means of which 

 they are enabled to rise into the air. — The actioji of 

 ivalk'mg in quadrupeds is deserving of particular no- 

 tice. The animal first slightly bends the articula- 

 tions of the hind legs, and then extends them in or- 

 der to carry forward the body. The breast being 

 thrown forward by this movement, the fore 

 legs become inclined backward ; and the animal 

 would fall, did it not instantly throw them forward 

 in order to support itself. It then draws up the trunk 

 upon the fore legs fixed in this position, and the hind 

 legs are again brought into action. But it must be 

 observed, that these movements are not performed at 

 the same moment, by the two legs of each pair in 

 the action of walking ; for in that case, the animal 

 would necessarily be completely suspended for a mo- 

 ment over the ground ; and its motion would then 

 be no longer a walk, but a succession of leaps, par- 

 ticularly denominated 2, full gallop. Each step is exe- 

 cuted by two legs only ; one belonging to the fore 

 pair, and the other to the hinder pair ; but some- 



