88 



OUTLINES OF NATURAL HISTORY. 



CHAPTER XXL 



CLASS REPTILIA. 



The class Reptilia (Latin, I'ejjto, I crawl) comprises all 

 the animals which are commonly called "Reptiles," ex- 

 cept the Amphibians, which would also be placed here by 

 popular consent, but which we have seen really to con- 

 stitute a distinct division. The living reptiles fall into 

 the four very distinct groups of the tortoises and turtles, 

 the snakes, the lizards, and the crocodiles and alligators. 

 It is difficult to choose any single tjqje which adequately 

 represents the entire class, and which is at the same time 



Fig. 40. —The Rattlesnake {Crotalus hurridus). 



readily obtainable for examination. We may, however, 

 select one of the venomous serpents, such as the Rattle- 

 snake, most of the remarks which will be made about 



