REPTILIA. 277 



The second sub-family, the Coilodontcs^ embraces species whose teeth 

 possess an internal cavity, and are applidl vertically against the inner wall of 

 the maxillary bones, their bases, however, never being in intimate union with 

 the bottom of the maxillary groove. All are natives of the old world, some liv- 

 ing entirely in a sandy desert, or places where their rapid motions are facili- 

 tated by a fringe of scales to the feet, preventing them from sinking in the 

 sand ; others, again, with smooth feet, live on trees, or play habitually along 

 walls and rocks. None are aquatic. Thetypical genus Lacerta {pi. 74, Jig. 

 79), widely spread in Europe and Africa, contains species eminent for the 

 quickness and beauty of their movements, as well as for their brilliant colors. 

 L. viridis {pi. 89. Jig. 7), is a species abundant on the continent of Europe, 

 but not found in Great Britain. 



Fain. 4. Iguanidce. This extensive family is well distinguished from the 

 three already considered, by the absence of large polygonal plates on the top 

 of the head. The body is furnished with scales, which are never arranged in 

 whorled rings, nor occur on the belly as large square plates. Most usually 

 the back or tail is provided with a crest, and there is a general tendency to 

 a greater or less degree of roughness externally. The teeth vary in their 

 mode of attachment, but are never implanted in sockets or rhizodont. 

 The moderate tongue is free at the extremity only : it is thick, spongy, or 

 villous, never cylindrical, nor playing in a sheath. The eyes are provided 

 with movable pupils : and the fingers are free, distinct, and all provided with 

 claws. 



Of the entire number of species belonging to this family, two thirds 

 (about 100) are natives of America. Of these, North America possesses a 

 considerable number, only three, however, being found within the limits 

 of the United States. The rest are found in Asia, Africa, and Australia ; 

 a single species only occurs in Southern Europe. Some of the Igua- 

 nidce., South American species especially, attain to a large size, and 

 constitute a favorite article of food. This is especially the case in the 

 vegetable-eating species. The eggs, too, of several are considered to be a 

 great delicacy. 



All the American species of Iguanidce. belong to one sub-family, that of 

 the Pleurodontes, distinguished from the natives of the old world, the 

 Acrodontes, in having the teeth applied along the internal margin of a 

 furrow excavated in the mandibles. These teeth, which are very close to 

 each other, diminish in height as they approach the extremity of the jaws. 

 The summits of the maxillary teeth are usually more or less trilobed ; in a 

 few species the edges are denticulated ; nearly all have one or tAvo ranges 

 of palatine teeth on each side. All possess an external auditory apparatus. 

 Some have the toes dilated, as in the GeckotidiB. 



Of the numerous genera (upwards of 50) into which the family Iguanidce 

 is divided, our space will permit us to mention only a few. The first that 

 comes under our review is the genus AnoUs {pi. I^^Jig- 69), distinguished by a 

 dilation of the skin of the penultimate joint of the toes ; by the presence of 

 palatine teeth ; by the minute scales ; and by the absence of pores on the 

 thighs. Of numerous species, but one is found in the United States. This 



ICONOGRAPmc EXCYCLOP.EDIA. VOL. U. 31 481 



