ORDER SAURIA; GENERAL CHARACTERS. 553 



but, from discoveries recently made among the Himalaya moun- 

 tains, it appears that Tortoises must have formerly existed, far 

 surpassing in dimensions the most bulky of the Chelonidse now 

 living. 



ORDER II. SAURIA. 



490. THE number of species included in this order is very 

 considerable : and their variation in form, dimensions, and cha- 

 racter, is far greater than is to be met with in the preceding 

 group. The contrast is still stronger, when we include in 

 our survey those fossil remains of the Saurian Reptiles, which 

 abound in many parts of the world ; for not even the gigantic 

 and ferocious Crocodile is nearly so striking in comparison with 

 the harmless little Lizard of our walls and copses, as were the 

 monstrous Saurians of the ancient streams and marshes, or the 

 Pterodactylus, which winged its Bat-like flight through the air. 

 The diversity in the habits of the existing Saurians is very con- 

 siderable ; some being more or less aquatic ; others strictly 

 terrestrial, living on the ground and retreating for shelter to 

 holes burrowed beneath the surface ; and others entirely arboreal, 

 passing their whole lives in the midst of trees. They mostly feed 

 on animal substances ; some of them preferring flesh, others 

 attacking small animals, and others pursuing insects; one family, 

 however, is for the most part herbivorous. They are all fur- 

 nished with teeth ; which are of a simple conical form, and 

 adapted rather for securing and tearing their prey, than for 

 masticating it. The chief families included in this order are the 

 following: 1. CROCODILID^E, or Crocodiles ; 2. CHAMELEONID^, 

 or Chameleons ; 3. GECKOTID.E, or Geckos ; 4. IGUANID^I, 

 or Iguanas ; 5. AGAMIDJE, or Agamas ; 6. VARANIDJE. or 

 Varans ; 7- TEID.E, or Teguixins ; 8. LACERTHXE, or True 

 Lizards; 9. CHALCID^:, or Snake Lizards; 10. SCINCID.E, 

 or Scinks ; besides certain fossil forms, which cannot be referred 

 to any of these. 



491. Some writers consider the family CROCODILIDJS as 

 forming a distinct order, intermediate between the Turtles and 



