GUIDE 



TO THE 



REPTILES AND AMPHIBIANS. 



I.— THE REPTILE SERIES. 



Class REPTILIA. 



According to popular ideas, all cold-blooded vertebrate (back- 

 boned) animals which do not come under the designation of Fishes 

 are denominated Reptiles. The naturalist, on the other hand, 

 divides these creatures into two main groups or classes, each 

 of which is of equivalent rank to the Mammalia (Mammals) or 

 Aves (Birds). 



The first class — Reptilia — comprises the true Reptiles, such as 

 crocodiles, snakes, lizards, and tortoises, and is characterised by the 

 fact that the young (whether hatched from eggs or born alive) 

 resemble their parents in most things except size and, perhaps, some 

 details of colouring, as soon as they come into the world and breathe 

 atmospheric air. Another feature is that the skull is attached movably 

 to the first joint of the back-bone, or first vertebra, by means of a 

 single knob, or "condyle" (fig. 1, a), which usually consists of three 

 separate portions, one in the middle and two at the sides. In the 

 presence of this single knob Reptiles resemble Birds and differ from 

 Mammals. They also agree with the former and differ from the 

 latter in that the lower jaw consists of a number of separate pieces 

 and is joined to the skull by means of an extra bone, the quadrate- 

 bone (fig. 1, q). 



The second class — Amphibia — includes, on the other hand, such 

 creatures as newts, salamanders, frogs, and toads, in the great 



B 



