AMPHIBIA (BATRACHIA) 



125 



creatures they depend for protection upon their activity, their protec- 

 tive coloration and in some cases, upon poison glands in the skin. 

 Many of them have considerable power of regenerating lost parts. 



PIG. 87. Mud puppy or water dog. Necturus maculatus. X;H}. 



FIG. 88. Hellbender or "Alligator, " Cryptobranchus allegheniensis. 



Although not one of the more important groups economically, prac- 

 tically all of the Amphibia are of some value to man, and few if any are 

 more injurious than beneficial. 



