362 ZOOLOGY 



tion was effected by a huge membranous expanse stretched 

 between the elongated posterior finger, the trunk, and the 

 hind legs. The spread of the wing was about three feet. 



The turtles, or Chelo'nia,' form an order distinct from the 

 hzards. They are characterized by a depressed form, a bony 

 case, and toothless jaws. Like other reptiles, they are most 

 abundant in tropical countries, since the high external tem- 



FiG. 340. — Hawkbill-turtle. Much reduced. From Brehm. 



perature compensates in a wajr for the insufficiency of the 

 mechanism for maintaining from the inside a high blood 

 temperature. Turtles are abundant in Africa, and are much 

 commoner in North America than in Europe. Three principal 

 families of Chelonia may be distinguished. A short account of 

 each follows. 



The family of marine turtles includes certain turtles that 

 live in all oceans, and may acquire a weight of as much as one 

 thousand pounds. The green turtle, used in making soup, 



1 Chelone, turtle. 



