MAMMALIA 



459 



stretching between the much extended fingers of the anterior 

 appendages; between the arm, body, and the hind legs; and 

 thence even to the tail. The thumb and posterior digits are 

 clawed. The sternum has a keel as in birds. The mammae are 

 thoracic. Bats are the only mammals capable of active flight. 

 They feed on insects or fruits. The members of one family, the 

 true vampires, live on blood of warm blooded animals. They 

 cut through the skin with sharp front teeth and lick up the 

 escaping blood. 



Bats are small animals and are chiefly nocturnal in habit, at 

 which time they fly actively. During the day they seek retired 

 and dark places where they hang head downward, holding on 

 by their claws. Those in temperate regions hibernate during 

 cold weather, often using caves for this purpose. (Pig. 242.) 



Order Primates {first or highest). — With the exception of 

 man the primates are arboreal in habit. In adaptation to this 



Fig. 243. 



Fig. 243. Hand and foot of Chimpanzee. From Home and Country Magazine. 



Questions on the figure. — Which is hand, and which foot? In what respects 

 do they differ? How do they differ from the hand and foot of man? In which 

 is the difference from the human condition greater? What is the functional 

 meaning of these differences? 



the thumb and great toe are usually opposable to the other 

 digits, as in the human hand. The digits are armed with nails 

 which are in some cases claw-like. The cerebrum is large and 



