2 STOKY OF THE AMPHIBIANS 



mals mentioned. Having two lives is the original 

 meaning of amphibious (from the Greek, amplii^ 

 two, and hios^ life). 



Some writers speak of this class of the vertebrates 

 as the Batrachians (from Greek hatrachios^ a frog), 

 but the author prefers to leave this term as the scien- 

 tific name of the tailless amphibians only. 



There are a few fishes that, when young, have a 

 tadpole state, but these, when grown, are easily distin- 

 guished from any amphibian, either because they have 

 no true legs, or because they have very distinct fins. 

 But there are many tadpoles of the amphibians, w-hich 

 outwardly resemble certain fishes, and close examina- 

 tion is required and technical terms must be used to 

 distinguish them. 



In a general way, every tadpole is a low order of 

 fish, having gills and living a thoroughly aquatic life, 

 but later they all either acquire true limbs with toes, or 

 else they have better lungs than has any fish. There 

 are fishes with lungs, but no legs. At the same time 

 there are many amphibians w^ith legs, that still retain 

 the gills of their tadpole state and have a very poor 

 sort of lungs indeed. 



From the classes above them the tadpole condition 

 of the amphibians is the most characteristic distinc- 

 tion, though some do not have this larval condition 

 outside of the Qgg. This Qg^g is also quite difi^erent 

 from that of reptiles and birds, and in the process of 

 hatching, the tadpole is not enclosed in certain sacs or 

 membranes, which grow round the young of the other 

 two classes and nourish them. 



