CLASS REPTILIA 



383 



much the appearance of a snake. This is true of the so-called glass 

 snakes of Europe and America, which are really hzards, and of some 



Scufe 



Ear opening 



Fig. 261. — Heads of a bull snake, Pituophis sayi (Schlegel), and of a lizard, Plestiudun 

 septcntrionalis Baird. A, head of the snake, from the side; B, from below. C, head of the 

 lizard, from the side; D, from below. A and B, X %; C and D, X 2. 



burrowing lizards, known as worm lizards, found in southern United 

 States. Legless lizards may be distinguished from snakes (Fig. 261) by 

 the presence of movable eyelids and an 

 external ear opening, both of which 

 snakes lack, and by having small over- 

 lapping scales on the ventral side of 

 the body instead of the transverse 

 scutes which snakes possess. The 

 tails of lizards are generally long, easily 

 broken off or separated into pieces, 

 and with equal ease more or less com- 

 pletely regenerated, though the re- 

 generated appendage does not possess 

 vertebrae. Lizards are in most cases 

 oviparous and the eggs are protected 

 by a thin shell with Uttle Ume in it. 

 They feed largely on insects, worms, 

 and other small animals and some are 

 to a considerable degree vegetable 

 feeders. 



Geckos (Fig. 262) are Hzards which 

 inhabit all warmer regions, are noc- 

 turnal, and have toes fitted for climb- 

 ing, thus enabling them to run over 



trees and rocks and even over the walls and ceilings of buildings. 

 The flying dragon, found in southeastern Asia and the East Indies, has 



Fig. 262. — Wall gecko, Tarcntola 

 mauritanicus (Linnaeus), of southern 

 Europe. {From Brehm, " Thierleben.") 

 ,3- 



X 2^ 



