SHEDDING OF SKIN IN SNAKES 



The young when they leave the egg are not coloured like 

 their parents, a common occurrence among animals ; 

 they also illustrate another common feature in the col- 

 oration of young creatures, which is that they are 

 striped. The young pig and the young tapir are other 

 examples of this same phenomenon. And it has been 

 attempted to be proved by these and other causes, that 

 animals in the course of their development go through a 

 regular series of colour changes which are necessary 

 accompaniments of that evolution. The tuatera can 

 bite, and that effectively, since it possesses what few 

 lizards do, an additional set of teeth upon the palatine 

 bones which form part of the roof of the mouth, addi- 

 tional, that is to say, to those upon the upper and lower 

 jaws. Its native name of tuatera seems to mean " pos- 

 sessing spines," and refers to its crest. 



SNAKES : THE ORDER OPHIDIA. 

 Although the limbless lizards, such as the blind-worm 

 and the European scheltopusik (Ophisaurus apus), dealt 

 with on a previous page, run the snakes rather close in 

 outward appearance, it is really not difficult to distinguish 

 by external appearance and behaviour the Ophidia from 

 the Lacertilia. The limbless, and so far, snake-like 

 lizard has a milder look than the true snake, whose re- 

 lentless and unwinking eyes produce even in the harm- 

 less kinds that feeling of repulsion which is apt to be felt 

 for the serpent. The mildness of the lizard is due to the 

 fact that it has movable eyelids, while the eyes of the 

 snake have no such eyelids, but are covered with a single 

 and transparent scale ; this is removed when the snake 

 sheds its skin and comes off with it in the form of a watch 

 glass. That the geckos have not for the most part eye- 

 lids does not lead to any confusion, for the blind-worms 

 which offer the most difficulties have. The movements 

 of the legless lizards have not that finished ease which 



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