542 



GENERAL CHARACTERS OP REPTILES. 



animals a lethargic dulness, analogous to that of hybernating 

 animals. 



481. Like Birds, Reptiles are destitute of mammae for the 

 suckling of their young, and are reproduced by eggs ; but these 

 eggs are sometimes hatched before they come out of the body 

 (in the Viper, for example) ; and the name of ovo-viviparous 

 is given to the animals in which this phenomenon is observed. 

 The mode of development of most Reptiles presents nothing 

 irregular; but Frogs, Toads, Salamanders, and other species 

 known to zoologists under the general term of Batrachians^ are 

 not born in the form which they ultimately preserve, and 

 undergo in the early state some remarkable metamorphoses. 

 They at first resemble Fishes in their external form, as well as 

 in their internal structure ; and it is by degrees, that they 

 acquire the characters peculiar to the class of Reptiles. Whilst 



FIG. 316. 



FIG. 320. FJG. 321. 



FIGS. 316 321. METAMORPHOSKS OF BATRACHIA. 



they are in this transitory state, the name of tadpoles is given 

 to them, and the metamorphoses which they undergo are greater 



