INTRODUCTION 



bygone reptiles have occupied in the past history of the 

 world. 



Some kinds of reptiles still existing are equally well 

 at home on land or in water, and there are others which 

 spend part of their time on one and the remainder in the 

 other. Snakes can and do take to water, though this 

 was for long disputed, but, as a rule, the Grass Snake is 

 more fond of this than the Adder, which exhibits a Uking 

 for dry situations. Matrix, the specific name of the 

 Grass Snake, means Water Snake, and it should be 

 stated that all Snakes are fond of drinking. Whilst 

 Snakes and Lizards are closely related, there are easy 

 distinguishing features, such as the absence in Snakes 

 of any functional limbs, and also the absence of eyelids. 

 The eye of a Snake has only a thin transparent covering, 

 and when, as happens, a Snake changes its skin, this 

 covering peels off in the form of a lens. On the other 

 hand the Slow, or Blind, Worm is not a Snake, and it 

 is certainly not a Worm. Neither is it blind. It is a 

 legless Lizard, having distinct eyelids. There are other 

 anatomical differences between the two Orders dealt 

 with in this first section, but these need not detain us, 

 and it only remains to be recorded that the greater 

 majority of the creatures contained in the Class Reptilia 

 deposit eggs, which are oblong in shape, and have a soft 

 leathery covering, or shell. In some kinds of Snakes, 

 however, especially those inhabiting fresh and salt water, 

 and also Lizards, the eggs are hatched within the parent's 

 body. This is so in the case of our own British Adder, 



