212 



VERTEBRATA 



in not having a forked tongue and in having eyelids and an 

 external ear opening on either side of the head. The 

 common lizard (Sceleporus undulatus) is widely distributed 

 over the United States. The skinks or striped lizards are 

 fast runners and abound in the central and southern por- 

 tion of our country. 



The chameleon (Anolis principalis) is the grass green 

 lizard of the South, which is capable of changing its color 



FlG. 243. The horned chameleon from Africa. Photograph two thirds natural 



size. 



to harmonize with its surroundings and thus escape the 

 eyes of the enemy. The chameleon famed in literature is 

 from Africa. 



The glass snake (Ophisaurus ventralis), ranging from 

 Wisconsin to Kansas and south, is remarkable for the com- 

 plete absence of limbs. More than twenty species of limb- 

 less lizards are known. There are a dozen species with 



