88 HALF-HOURS IN THE GREEN LANES. 



frog or toad, in which, as a tadpole, it breathes by 

 gills, and has a fishlike tail instead of limbs, is 

 permanently represented by the perennibranchiate 

 reptile, the Proteus. Again, in higher order, the 

 next stage in the life-history of the frog, when the 

 external gills have disappeared, but when the tail 

 is still present, is permanently represented by the 

 adult condition of the various species ol newts. 

 Such, also, seems to have been the rule which re- 

 gulated this class of creatures in their appearance 

 on the stage of existence in the various geological 

 epochs. The first species were amphibians, of 

 marine habits, much resembling the newts, or 

 possibly the Proteus, only much larger. This, as the 

 Archsegosaurus, swarmed in the early Carboniferous 

 seas. Next came the labyrinthodont frog-like animals 

 (Batrachians), to which all the carboniferous amphi- 

 bians even of the later period belong, with the excep- 

 tion, perhaps, of a species of tree lizard. During the 

 Triassic epoch, gigantic Batrachians abounded, and 

 assumed that external, tailless appearances peculiar 

 to our frogs and toads. Lastly, it was later on that 

 the higher forms of reptiles appeared, and as the 

 Secondary ages passed away, the principal zoological 

 feature was their differentiation so as to people the 

 seas, oceans, rivers, lakes, swamps, the dry land, and 

 even the air, with their various forms ! 



Let us now quit for a while the bank of the tarn 

 on which we have been so long engaged, and seek 

 for other objects, most of which will be found in 



