CLASS REPTILIA: ORDER LACERTILIA. 171 



Alligatoridae. The Alligator belongs to the New World. 



Fig. 287. 



Alligator missiszippiensis, Alligator. 



In the colder portions of, its habitat it hibernates in the mud, 

 but within the tropics is active at all seasons. 



ORDER LACERTILIA. 



General Characteristics. The teeth are simply at- 

 tached to the surface of the jaw. In the Leptoglossa 

 (slender- to ngued) group, the tongue is long, nicked, and 

 enclosed in a sheath, from which it can be protruded through 

 a notch when the jaws are closed. In the Pachyglossa 

 (thick-tongued), this organ is fleshy, and can be thrust out 

 only when the mouth is open. 



Chamaeleonidae. The Chameleon is confined to the Old 



World.* It leads a double 

 life. It may be asleep on one 

 side and awake on the other. 

 One eye can watch an insect 

 crawling in the rear, and the 

 other in front. When agitated, 

 each half of its body wishing 



Chamcelton vulgaris, Chameleon. * 



* Many of the stories current about the chameleon's change of color are doubt- 

 less fabulous ; yet it can become at pleasure yellow, green, or black. " In the skin," 

 says Bert, " there is a network of minute ducts, connecting with pigment-vesicles 

 on the under surface, which contain the coloring liquid. The tint of the animal 

 depends on the amount of this liquid injected into the ducts." The process seems 

 somewhat analogous to that of blushing in the human species. 



