314 ELEMENTARY ZOOLOGY. 



319. Reproduction and Development. In the reptiles, 

 as in the bird and mammals, the fertilization takes place 

 inside the body. It must occur before the egg is encased 

 in its shell, which is added in the lower part of the oviduct. 

 The eggs of the reptiles are large, similar to those of birds. 

 They are usually deposited in small numbers in depres- 

 sions or holes in the ground or in the sand at the edge of the 

 water, or under stones or other objects. For hatching 

 they must depend upon the warmth of the sun or of 

 decaying organic matter in which they are sometimes 

 placed. Usually little care is given after laying; but the 

 aligators guard their nest and the young. Some snakes 

 and lizards retain the eggs in the body until hatched. 



In all these forms the young, when it leaves the egg, 

 is a miniature of the adult, and able to care for itself. 

 There is no metamorphosis. 



320. Place in Nature. The reptiles are for the most 

 part sluggish animals. Many of them like to lie and 

 bask in the sun. The largest species are tropical forms. 

 They are muscular and are capable of rapid motions, 

 but this is not so continuous as in the birds. Cold weather 

 always checks their activities. Those that inhabit 

 temperate regions hibernate in winter. 



The reptiles live largely on animal food, such as worms, 

 insects, fish, small birds and mammals, eggs, and the 

 like. Not a great many animals depend on the reptiles 

 for food. They seem rather less preyed upon than most 

 animals. Some of the predaceous birds eat snakes and 

 lizards. 



As a group they are relatively of little importance to 

 man one way or the other. The cobra of India is said to 

 cause 25,000 deaths in one year; but aside from this the 



