224 VERTEBRATA : EEPTILIA OR REPTILES. 



SUB-SECTION V. 



THE ORDER OF LACERTIA OR LIZARDS. 



THE Lacertias are saurian reptiles whose bodies are 

 covered with scales, and whose vertebrae are concave 

 before and convex behind, or concave on both faces. They 

 have only two, or at most three, vertebrae in their sacrum. 

 None of the living species have teeth set in sockets. The 

 heart has two auricles and one ventricle ; the ventricle is, 

 however, partially divided by a partition into a right and 

 left portion. 



FIG. 256. 



Striped Lizard, Ameiva sex-lineata, Cuvier. 



Some of the members of this order, as the Green Lizard 

 and Striped Lizard of our Southern States, are only six 

 to ten inches in length. Others, like the Monitor of the 

 Nile and the Iguana of South America, are from four to 

 six feet in length. Some, like the Dragons (Draco) of the 

 East Indies, have their ribs extended outwards and sup- 

 porting a fold of skin, and thus forming a sort of wing 

 which acts as a parachute in sustaining them as they leap 

 from one tree to another, and thus making, them appear 

 as if flying. Others, like the Geckos (Fig. 257) of the 



