62 



GUIDE TO EEPTILES AND AMPHIBIANS. 



IL— THE AMPHIBIAN SERIES. 



Class AMPHIBIA, or BATRACHIA. 

 (Tahle-Gase in Middle Line of Gallery.') 



As already mentioned, Frogs, Toads, Newts, and Salamanders are 

 commonly regarded as Reptiles ; but, together with certain allied 

 creatures, they differ, as a whole, from true Reptiles by several well- 

 marked features, and they are accordingly assigned to a separate 

 class, the Amphibia, or Batrachia. A general feature of this class 

 is the marked difference between the young (commonly called tad- 

 poles) and the adults ; the former living in water and breathing by 

 external gills, while the latter are largely terrestrial and breathe by 

 lungs. Some types, such as the 01m, are, however, permanently 

 aquatic and gill-breathing ; while in certain Frogs the transformation 

 process is hurried through within the eggs from which full-formed 

 Frogs emerge. In the living kinds the skin is mostly smooth, clammy, 

 and devoid of scales. The skull articulates with the first vertebra by 

 two knobs or condyles instead of by one, as in Reptiles. The hind- 

 limbs (when present) are nearly always five-toed in the adult, but 

 the front-limbs are very generally four-toed. 



The following table exhibits the orders and families into which 

 the class is divided. 



Order I.— ANURA 



(Frogs and 

 Toads). 





Family Pipidce. 



■ ] „ DactyUthridce,. 



^ ( „ Discoglossidce,. 



tt. I „ Pelolatidm. 



„ BvfonidcB (Toads). 



„ Hylidce.. 



„ GystignathidcB. 



^ f „ Dyscophid(B. 



„ Ewiystomatidce.. 



„ Bendrobatidm. 



„ RaiiidcB (Frogs). 



