340 SYSTEMATIC ZOOLOGY. 



comparatively small, the largest being the giant sala- 

 mander of Japan, which may be three to four feet in 

 length. Existing Amphibia are conveniently divided into 

 three groups or orders: Csecilia, Urodela, and Anura. 



ORDER I. CSECILIA (Blindworms). 



These are legless, worm-like Amphibia found in the 

 tropics of both hemispheres. They have a rudimentary 

 tail, degenerate eyes, and the larvae, so far as known, have 

 three pairs of gills. Some species form an exception to all 

 living Amphibia inliaving scales in the skin. While highly 

 modified in some respects, in others they are the lowest in 

 position. They live a burrowing life, feeding upon earth- 

 worms, insects, etc., found in the soil. 



ORDER II. URODELA (Salamanders, Newts, etc.). 



These forms retain the tail throughout life, and have the 

 extremities weakly developed, fitted for creeping rather 

 than jumping. Some live in the water throughout life, 

 while others, as adults, are to be sought in moist places. 



FIG. 140. Salamander (Plethodon). 



In some forms the external gills are retained permanently. 

 The order belongs almost exclusively to the northern 

 hemisphere, and is especially well developed in America. 

 Allied to the Urodelans and Csecilians are some enormous 



