INTRODUCTION 



Reptiles, as well as Batrachians and Fishes, are cold- 

 blooded vertebrate animals, the temperature of their 

 bodies, unlike as in the case of Mammals and Birds, rising 

 and falling according to their surroundings. 



From Batrachians, Reptiles differ in breathing hy 

 lungs during the whole of their existence, and not by gills 

 as do the former during at least part of their life, and by 

 the fact that the skull, which in Batrachians, as in 

 Mammals, articulates with the vertebral column by two 

 rounded knobs or condyles, is in Reptiles attached as 

 in Birds by a single condyle. Unlike Batrachians, they 

 undergo no metamorphosis, being born in the condition 

 which they will retain for the whole of their life. 



In the majority of Reptiles the skin is covered with 

 scales or shields, while in Batrachians it is, with a few 

 exceptions, naked. 



The living representatives of the class Reptilia, the 

 majority of which occur in the tropical and semi-tropical 

 parts of the world, are divided up into the following five 

 orders — 



I. The RHYNCHOCEPHALIA:— The Tuatera Lizard 

 of New Zealand, the survivor of an order of which 

 numerous fossil representatives are known. 

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