22 CLASS REPTILIA. 



scattered debris of gigantic vegetables. We may pursue 

 their evolutions over the tranquil surface of lakes, of streams, 

 and rivers; mark the tortuous folds by which they attach 

 themselves to the branches ; and unveil the mechanism by 

 which they creep, climb, walk, run, leap, and even fly. 



Reptiles consist of oviparous quadrupeds and serpents. 

 To the first, the name of reptile is as suitable as to the last : 

 for though they have feet, they make little use of them, except 

 in creeping, and their belly almost always touches the ground. 

 Tortoises, lizards, frogs, toads, and salamanders, afford suffi- 

 cient proof of this. Though the three last-mentioned genera 

 live in the water, and swim there with facility, they also live 

 on land very well. For this reason some natviralists have 

 considered them as true amphibia. But, in fact, for an ani- 

 mal to be amphibious, in the strictest acceptation of the 

 term, it is necessary that it should possess the power of 

 respiring under the water like fishes, and on the earth like 

 man— none, therefore, of these animals are true amphibia, 

 except, perhaps, the siren and the proteus, which possess 

 both lungs in the chest, and external gills. Frogs, toads, 

 and salamanders, when in the tadpole state, are provided 

 only with gills, which respire the water, and, accordingly, in 

 this tadpole state, they cannot live out of the liquid element. 

 When they become perfect animals the gills disappear, and 

 they breathe by lungs, consequently, they are then obliged 

 to respire the air, and would perish by suffocation under 

 water, were they forced to remain submerged for too long a 

 period of time. 



It is the more necessary to insist on all this, as the term 

 amphibious^ in popular language, like most other terras of 

 Natural History, is grievously abused — we have heard it 

 applied to the hippopotamus, the seal, and even to the 

 beaver. 



There are fewer links of connexion in reptiles than in birds 



