HIGH SCHOOL ZOOLOGY. 107 



like the large water-lizards of the Nile, do not exhibit any special 

 adaptation for locoiuotion in water. Most of the forms are 

 terresti'ial in their habits while some are arboreal, and others 

 lead a subterranean life. In accordance with such differences 

 in the surroundings, we find great differences of external form. 

 The members of the order ai-e especially abundant towards the 

 tropics, only two families being represented further north by 

 the Blue-tailed Skink (Eumeces quinquelineatus) and the Brown 

 Swift or Pine-treo lizard (Sceloporus unduhihis). Both of 

 these lizards are of small size and veiy active creatures, the 

 last mentioned belonging to a large family the Iguanidae, which 

 embraces most of the New-World lizards. The forms which 

 lead an active arboreal life are generally compressed in shape, 

 while those which creep about in sandy places depending on 

 their colour for protection, like the Horned Toad of the Southern 

 States (Phrynosoma cornutum, Fig. 77), are depressed. Among 



Kg. 77— Horned Toad. Phrynosoma cornutum. 

 (After Brehm). 



the largest members of the family are the great Iguanas of the 

 Brazilian forests, which are alike remarkable for their size and 

 for the singular crests and combs with which the skin is adorned. 

 An old workl family the Agamidae contains forms which 



