CHAPTER I. 



AMPHIBIA, OR BATRACHIANS. 



Those geographers who divide the world into land and sea over- 

 look in their nomenclature the extensive geographical areas 

 which helong permanently to neither section — namely, the vast 

 marshy regions on the margins of lakes, rivers, and ponds, whicli 

 are alternatel}'' deluged with the overflow of the adjacent waters, 

 and parched and withering under the exhalations of a summer 

 heat ; regions which could only be inhabited by beings capable of 

 living on land or in water ; beings having both gills through 

 which they may breathe in water, and lungs through which 

 they niay respire the common air. The first order of rei3tiles 

 possesses this character, and . hence its name of Amphibia, from 

 ayn</)t/3tos, having a double life. 



The transition from fishes to roptdes is described by Professor 

 Owen, with that wonderful powerof condensation which he possesses, 

 in the following terms ; — " All vertebrates during more or less of 

 their developmental life-period float in a liquid of similar specific 

 gravity to themselves. A large proportion, constituting the lowest 

 organised and first developed forms of this province, exist and 

 breathe in water, and are called fishes. Of these a few retain the 

 primitive vermiform condition, and develop no limbs ; in the rest 

 they are 'fins' of simple form, moving by one joint upon the 

 body, rarely adapted for any other function than the impulse 

 or guidance of the body through the water. The shape of the 

 body is usually adapted for moving with least resistance through 

 the liquid medium. The surface of the body is either smooth 

 and lubricous or it is smoothly covered with ovei'lapping scales ; it 

 is rarely defended by bony plates, or roughened by tubercles. 



