Order IV. BATRACHIA. Brogniart. 



The many and great differences that exist between this and the three preceding 

 orders of reptiles, have led several excellent herpetologists of our day to arrange 

 the animals it includes as a distinct class, named Amphibia; as they are in fact, 

 at one time, animals that live in water, and respire by means of gills, like fishes, 

 and at another they breathe atmospheric air with lungs, like mammalia. 



CHARACTERS. 



1. The body is depressed, round, or elongated, and with or without a tail; the 



skin is soft, naked, or without a shell, and most commonly without apparent 

 scales, (ccecilia.) 



2. The extremities vary in number and proportion, or are entirely wanting. The 



fingers and toes are destitute of nails, and are rarely provided with a horny 

 sheath, (Datylethra.) 



3. There is no neck distinct from the body, and the head is joined to the vertebra 



by two condyles. 



4. There are in general three movable eyelids, and no visible external meatus of 



the ear, though the tympanum is often very distinct. 



5. The sternum is distinct in most species, but is never joined to the ribs, which 



are either very short or entirely wanting. 



