THE REPTILIA 319 



water or after the living animals have been suspended over a 

 fire. In the latter case the animals are liberated and allowed to 

 regenerate a new covering of shields. The regenerated shields, 

 however, are not of commercial value. Hawk's-bill turtles are 

 smaller than green turtles, reaching a weight of about thirty 

 pounds and a shell length of thirty inches. They are carnivo- 

 rous, feeding largely on fish and mollusks. 



The leathery turtle is the largest of all living turtles, sometimes 

 attaining a weight of a thousand pounds. It has a leathery 

 covering over the shell instead of horny shields. It inhabits 

 tropical and semitropical seas and goes to land only to deposit 

 its eggs. The limbs are modified as flippers for swimming. 

 The flesh is not used for food. 



LIZARDS 



The lizards resemble salamanders in their general outlines, but 

 as already noted (p. 299) , they are covered with an exoskeleton of 

 scales. Among the common species living in this country are the 

 chameleons, iguanas, horned " toads," gila monsters, and skinks. 



The chameleon lives in southeastern United States and in Cuba. 

 It is able to change its color very rapidly so as to match its sur- 

 roundings, thus concealing itself and gaining protection. 



From southwestern United States southward huge iguanas 

 (Fig. 197) are commonly seen lying on stone fences or on the 

 limbs of a tree sunning themselves. They reach a length of six 

 feet, feed on insects and other small animals, and are considered 

 very good to eat by the natives of tropical America. 



The horned " toads " (Fig. 198) of the western United States 

 are really lizards. Their bodies are provided with a very heavy 

 covering of scales and spines, which, besides protecting them 

 from enemies, prevents the evaporation of water, thus enabling 

 them to live in hot, dry, desert regions. Specimens can be kept 

 in the laboratory if placed in a warm, dry place. They feed on 

 insects in their natural habitat and will thrive on meal worms 

 in captivity. 



