HOW EBPTILES ARE BORN 173 



The female crocodilians frequently remain in the 

 yicinity of the eggs until they hatch, but their pres- 

 ence in no way appeals to the development of the 

 young. The eggs of the crocodilians are generally 

 deposited in heaps of decomposing vegetable matter 

 scraped together by the mother. 



Among the snakes a number of species bring 

 forth the young alive. The poisonous snakes, except- 

 ing the cobras and allied species (the ElwpidoB), pro- 

 duce the young alive. From th^ moment of their 

 birth the young snakes are provided with venom- 

 bearing fangs, and are, moreover, fully capable of 

 using them. The characteristic of bringing forth 

 the young alive belongs also to a large number of 

 thci. harmless snakes. Species that lay eggs are called 

 oviparous snakes ; those that give birth to living 

 young are scientifically termed ovovvviparous species. 

 Although belonging to the same family, the Boidoe, 

 the pythons of the Old World, lay eggs, while the 

 boas, which inhabit the Western Hemisphere, pro- 

 duce fully developed young. 



The number of young brought forth by different 

 species of snakes varies greatly. Our common gar- 

 ter-snake, an ovoviviparous species, produces on an 

 average about thirty -five young; the common water- 

 snake occasionally gives birth to yet larger broods ; 

 on one occasion a specimen in the writer's possession 

 gave birth to sixty thriving youngsters. 



The majority of the highly poisonous snakes 

 bring forth comparatively small broods, their number 

 seldom exceeding fifteen. Some of the tropical 



