TRUE REPTILES. 



215 



of motion (Fig. 258). The toes are provided with cling- 

 ing ridges of bristles, by which they walk upon the walls 

 in search of insects, though in the forest species this ar- 

 rangement is sometimes absent. The jaws have small 

 teeth, and the tongue is not extensible. 



FIG. 257. Horned lizard (Phrynosoma cornutuni). 

 Dorsal view and side view of head. 



FIG. 258. Gecko. 



The Scinks (Scinkida) are spindle-shaped (Fig. 259) 

 and covered with smooth scales. The five-lined and red- 

 headed scinks are common in the Southern States. The 

 Glass Snakes (Chalcidce) have no feet, the body being 

 serpent-like (Fig. 260). The glass snake 



FIG. 259. Scink (Scincus offictnah's), showing structure of the feet. 



have also been seen devouring their own cast-off skin and wriggling 

 tail. The geckos of the East Indies utter a shrill cry. The leaf-tailed 

 gecko is one of the most curious. One species is said to be luminous. 

 They are all insect-eaters. Two hundred species are known. 



