1 8 KEPTILES AND BIRDS. 



aerial respiration, and so ought to form a separate class of Verte- 

 brates.* 



Batrachians establish a transitional link between Fishes and 

 Reptiles they are, as it were, a bond of union between those two 

 groups of animals. In the adult state Batrachians are cold-blooded 

 animals with incomplete circulation, inactive respiration, and the 

 skin bare. In the introductory section to this chapter we have given 

 the general characteristics which belong to them. The Frogs Tree 

 Frogs, Toads, Surinam Toads, Salamanders, and Newts are the re- 

 presentatives of the principal families of Batrachians of which we 

 propose giving the history. 



The Frogs (Rana} have suffered injury by their resemblance to 

 Toads. This circumstance has given rise to an unfavourable pre- 

 judice against these innocent little Batrachians. Had the Toad not 

 existed, the Frog would appear to us as an animal of a curious form, 

 and would interest us by the phenomena of transformation which it 

 undergoes in the different epochs of its development. We should 

 see in it a useful inoffensive animal of slender form, with delicate and 

 supple limbs, arrayed in that brilliant colouring which is so pleasant 

 to the eye, and which mingles so harmoniously with the carpeting of 

 our fields. 



The body of the Edible Frog, Rana esculenta (Fig. 4), sometimes 

 attains a length, from the extremity of the muzzle to the end of the 

 hind feet, of six to eight inches. The muzzle terminates in a point ; 

 the eyes are large, brilliant, and surrounded with a circle of gold 

 colour. The mouth is large ; the body, which is contracted behind, 

 presents a tubercular and rugged back. It is of a more or less 

 decided green colour on the upper, and whitish on the under parts. 

 These two colours, which harmonise well, are relieved by three yellow 

 lines, which extend the whole length of the back, and by scattered 

 black marblings. It is, therefore, much to be regretted that prejudice 

 should cause some at least of us to dislike this pretty little creature. 

 For ourselves, we cannot see the banks of our streams embellished 

 by its presence and animated with its gambols without pleasure. 

 Why should we not follow with our eyes their movements in our 

 ponds, where they enliven the solitude without disturbing its tran- 

 quillity? Frogs often leave the water, not only to seek their nourish- 

 ment, but to warm themselves in the sun. When they repose thus, 



* They are regarded by some naturalists as a sub-class of Fishes rather than 

 as Reptiles ; as piscine forms, certain of which develop to a parallelism with the 

 ordinary reptilian condition of advancement ; their reproduction especially favour- 

 ing this view. ED. 



