Frogs and Toads 



599 



EDIBLE FROG. 



The hind legs only of this species are used for the composition of the 

 famous Parisian dish. 



Amphibia is. afforded by the circumstance that 

 they all pass through a transitional or larval 

 condition before arriving at the adult state. 

 The familiar tadpole phase of the common frog 

 or toad typically illustrates this point. During 

 its earliest larval state the fish-like resem- 

 blance is especially conspicuous. In addition 

 to possessing gills, the body is limbless, and 

 produced into a long fish-like tail, having 

 superior and inferior fin-like membranes, 

 with which the little animal propels itself 

 through the water. These locomotive fins, 

 however, are never furnished with supporting 

 fin-rays, as obtains among the Fishes. In 

 contradistinction to the Lizards and Snakes, 

 the skin of Amphibians is never covered with 

 spines or scales, but is soft and naked. In 



many of the Toads and Salamanders the surface of the skin is, however, warted and highly 

 glandular, and capable of emitting an acrid and sometimes poisonous fluid. More or less 

 pronounced conditions of moisture are essential for the well-being of all Amphibians. The 

 eggs are deposited, and the earlier or larval conditions, with but few exceptions, passed, in 

 the water, while the adults remain in its near proximity, and frequently take up their abode 

 in it. Amphibia do not, however, drink water after the manner of lizards and other reptiles, 

 but absorb all the moisture they require through the surface of their skins. The deeper 

 and more essential skeletal elements of the Amphibia differ conspicuously from those of the 

 preceding groups. The vertebrae in the permanently gill-bearing species more particularly 

 are scarcely to be distinguished from those of fishes. In the Frog and Toad Tribe, on the 

 other hand, they are reduced to a less number, seven or eight only, than is found among 

 any other vertebrates, while ribs do not exist or are rudimentary and functionless throughout 

 the class. Many bones of the skull in the Amphibia, as well as its general construction, are 

 more in accord with those of fishes than of ordinary reptiles. The tongue, not always present, 

 is attached immediately inside the front of the lower jaw, its tip pointing down the animal's 

 throat. It is remarkable that, notwithstanding their aquatic proclivities, no Amphibian has 

 been discovered which frequents salt water. 



Amphibians amongst themselves constitute two very easily recognised sub-divisions, the 

 one including the Frogs and Toads, collec- 

 tively forming the Tailless group ; and the 

 other represented by the Newts and Sala- 

 manders, or Tailed Amphibians. The former 

 group has an almost world-wide distribution, 

 numbering some thousand species; it is most 

 abundantly represented in the tropics, rang- 

 ing thence in diminishing numbers to the 

 limits of the Arctic Circle. In colder climates 

 these Amphibia usually hibernate during the 

 winter months ; while in tropical countries, 

 where dry seasons intervene, they often 

 bury themselves in the mud, and remain 

 in a state of torpor till the return of the 

 rains. The majority are more or less es- 

 sentially nocturnal in their habits. Frogs 

 and toads commence life in an aquatic 



Photo by W. P. Dando, F.Z.S.] 



TIGER-LIKE FROG. 



[Regent's Park. 



A species closely allied to the common British frog, but more boldly 

 marked. 



