10 CALIFORNIA ACADEMY OF SCIENCES. 



be mentioned here, since the batraehians will not be 

 considered in the following pages. Our reptiles and 

 batraehians may be distinguished by the following 



SYNOPSIS OF CLASSES. 



a. — Anal opening transverse or round; skin furnished with scales (varying 

 from large plates to minute granules); or, if skin smooth (Pelo- 

 discus), tail and claws present and jaws without teeth. {Turtles, 

 lizards, snakes, etc.) Reptilia. — p. 28. 



a'^ — Anal opening longitudinal or round; skin smooth or warty, without 

 boales; no claws.* (Frogs, toads, salamanders, newts, water-dogs, 

 tadpoles, etc. ) Batrachia. 



Long ago the reptiles were the rulers of the earth as 

 the mammals are to-day. Huge monsters, most gro- 

 tesquely fashioned, roamed over the land, while equally 

 large reptiles swam in the seas, and in the air were 

 great creatures whose bat-like wings, it is said, some- 

 times measured more than twenty feet from tip to tip. 

 But of these monsters, none remain alive; only the 

 smaller forms have survived. Living reptiles fall natu- 

 rally into four groups or orders. One of these orders 

 contains but a single lizard-like animal, the Sphenodon 

 of New Zealand, interesting to the morphologist be- 

 cause of its generalized structure. The other three 

 orders are numerously represented in the warmer por- 

 tions 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 subtropical distribution and do not enter the terri- 

 tory we are considering. The turtles are most numer- 

 ous 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 



* Tips of digits sometimes borny. 



