18 INTRODUCTION 



Synopsis of Classes 



a. — Anal opening transverse or round} skin furnished 

 with scales (varying from large plates to minute 

 granules); or, if skdn smooth, tail and claws present 

 and jaws without teeth. (Turtles, lizards, snakes, 

 etc) Reptilia. — p. 48. 



a.' — Anal opening longitudinal or round; skin smooth or 

 warty, without scales; no claws.* (Frogs, toads, sala- 

 manders, newts, waterdogs, tadpoles, etc.) 



Amphibia. 



Long ago, reptiles existed in greater numbers and more 

 varied form than now. Many of them were of huge size. 

 They lived not only on land and in water, but certain kinds 

 had wings and flew through the air. The remains of these 

 large and often grotesque creatures are found in' the rocks. 

 None of these reptilian monsters remains alive; only the 

 smaller forms have survived. Living reptiles fall natur- 

 ally into four groups. One of these contains but a single 

 lizard-like' animal, the Sphenodon of New Zealand, inter- 

 esting to the morphologist because of its generalized struc- 

 ture. The other three groups are numerously represented 

 in the warmer portions of both the Old and New Worlds. 

 They are: first, the alligators and crocodiles; second, the 

 turtles; third, the lizards and the snakes. 



The alligators and crocodiles are of chiefly tropical and 

 sub-tropical distribution, and do not enter the territory we 

 are considering. The turtles are most numerous in moist 

 regions, and, consequently, are represented on the Pacific 

 Coast and in the Great Basin by few species. The lizards 

 and snakes, on the contrary, find our warm, dry climate 

 well adapted to their needs, and are very numerous. In 

 the following pages there are admitted to the fauna of the 

 states under consideration 232 species and subspecies of 



* Tips of digits sometimes horny. 



