LESSONS IN ZOOLOGY. 297 



tates a moist atmosphere. In larval life they live mainly on 

 vegetable matters, in adult life on insects. 



As a rule, their movements are sluggish, and the need of food 

 is relatively small, so that they live for months without food. 

 They also have the power of reproducing lost parts, as the limbs 

 or tail. 



The Apoda are worm-like amphibia, without limbs, that were 

 for a long time thought to be snakes. They live in tropical 

 climates and are of no special interest beyond the question of 

 relationship. 



The Caudata have four short limbs and a persistent tail, some- 

 times retaining external branchia through adult life. 



This group includes the sirens, the mud puppies, which have 

 external gills, and the land and water salamanders which have 

 no gills. 



The Batrachia are tailless amphibia with naked skin and well 

 developed extremities. This group includes water frogs, land 

 frogs, tree frogs, toad frogs and toads. 



