180 ANIMAL BIOLOGY 



are lizards with flattened bodies and short tails. Their 

 color resembles that of the soil. They readily live in cap- 

 tivity if fed upon the living insects. One of the largest of 

 North American lizards is the Gila (pronounced heela) 

 monster which is found in Arizona, New Mexico and Mexico. 

 It is heavy, stocky animal and, unjike most lizards, 

 usually sluggish in its habits. It is the only North Ameri- 

 can lizard whose bite is poisonous, the venom being 

 conveyed to the wound by grooves in a pair of large 

 teeth. 



There are some lizards which have lost their legs, like the 

 Ccecilians among the Amphibia, and they are frequently 



FIG. 142. Horned toad, Phrynosoma blainvillei. (After Bryant.) 



therefore mistaken for snakes. Such is the case with 

 the so-called joint-snake or glass-snake which receives 

 its name from the fact that its tail is readily broken into 

 fragments. This is because it is a lizard and not a true 

 snake. There is a prevalent myth that the glass snake 

 gathers together the joints of its tail and becomes whole 

 again, but it is perhaps needless to say that the story is 

 without foundation in fact. 



The Crocodilians have the appearance of immense 

 lizards, although they are quite different from the lizards 

 in structure. In the United States they are represented 

 by alligators of the southern rivers and by a species of 



