ANIMALS AND THEIR ENVIRONMENTS. 



315 



ranking next in order to that of the fishes, we may find 

 examples of the relationship between living beings and their 

 surroundings, if anything, of more typical and distinct nature 

 than those presented by the flat-fishes. This group of ani- 

 mals is known as that of the amphibia, and is represented 

 by the frogs, toads, newts, and allied animals, which, in 

 popular phraseology, would be termed "reptiles," although 

 zoologically they form a perfectly distinct group from the 

 latter creatures. It may facilitate the comprehension of the 



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FIG. 62. Metamorphosis of the frog. 



illustrations about to be brought forward, if we firstly glance 

 at certain of the chief characters by which the class of am- 

 phibians is distinguished. 



The newts, frogs, toads, and their allies, without ex- 

 ception, pass through a series of changes in form (or meta- 

 morphosis] in their young condition, and possess breathing 



