FIRE-BELLIED FROGS (liat. size). 
AMPHIBIANS. 
CHAPTER I. 
General Characteristics,— Class Amphibia. 
Frogs and Toads, —Order Ecaudata. 
In popular estimation frogs and toads, together with their near relatives the newts 
and salamanders, are regarded as Reptiles, but they are really very different, and 
constitute a class by themselves, being in many respects intermediate between 
Reptiles and Fishes. From the mode of life of its members the very appropriate 
name of Amphibians has been proposed for the class, and is the one which should 
be adopted, although the term Batrachians, which more properly applies to frogs 
and toads alone, is not unfrequently used in the same sense. Agreeing with the 
higher Vertebrates in the structure of their limbs, which are divided into the same 
number of segments as in Mammals and Reptiles, and supported by corresponding 
bones, existing Amphibians are distinguished from Reptiles by the absence of any 
ossification in the basioccipital region of the lower surface of the hinder-part of 
the skull, in consequence of which the latter is articulated to the first vertebra by 
means of two condyles formed exclusively by the exoccipital bones. A further 
important point of distinction is afforded by the absence in the embryo of those 
membranous structures known as the amnion and allantois. Moreover, the great 
majority of Amphibians pass through a metamorphosis, or rather a series of 
vol. v .—17 
