136 CLASSIFICATION OF AMPHIBIANS. 



young come forth alive : the duties of the parent are 

 thus superseded, and the offspring are left to seek their 

 own nourishment. The food of these reptiles is wholly- 

 animal : the larger prey upon quadrupeds and birds 

 proportionate to their size ; while the smaller devour 

 animals of their own class, together with insects and 

 worms ; but the nature of their teeth, admirable indeed 

 for securing their prey, are useless for the purpose of 

 mastication : their food is therefore gorged in an entire 

 state, and is frequently so bulky, that nearly one half 

 protrudes, as it is said, from the mouth, while the 

 other portion is undergoing digestion. Nearly all ser- 

 pents are terrestrial, yet many resort chiefly to trees, 

 others to marshes, and some few are entirely aquatic. 

 In these latter, the tail is sufficiently flattened and 

 dilated to serve the office of a fin, by which they pass 

 through the water with gTeat swiftness. This swimming 

 power, however, in some degree, is shared by nearly all 

 of the terrestrial serpents, for even the common snake 

 of this country has been frequently seen out at sea. In 

 their geographic distribution there is nothing remark- 

 able, save that, as heat is more congenial to serpents 

 than cold, we find them most numerous, formidable, 

 and bulky in the tropics. Such as inhabit temperate 

 or colder countries, retire to holes and recesses during 

 winter, where they remain without food, and in a state 

 of torpor, until the return of spring brings them, and 

 the insect tribes upon which they feed, to active life. 



(136.) The arrangements proposed for this order are 

 as numerous as the authors who have written upon it : 

 yet as no advantage, but the contrary, would result 

 from giving a dry detail of artificial systems, we must 

 mention with honour the names of Laurenti, Lacepede, 

 and Daudin, as men who have contributed valuable 

 works which have considerably extended the know- 

 ledge of this department of nature. ^Nlore recently, the 

 works of ]Merrem, Oppel, Cuvier, Wiedman, Wagler, 

 Fitzinger, Spix, Dumeril, Bibron, &c., among con- 

 tinental herpetologistSj of Bell and Gray in our own 



