CLASS AMPHIBIA 



475 



directly beneficial to the animal when they help it to resemble more 

 closely its surroundings and thus avoid capture. 



The Skin. — Amphibians have a soft, moist skin which is kept in 

 that condition primarily by a rich supply of mucous glands. Aquatic 





Fig. 261. — Spadefoot toad, Scaphiopus coucliii, showing the shape of the pupil of 

 tlie eye. (Photograph by Thos. Mebane Jones.) 



Fig. 262. — Feet of spadefoot toad, Scaphiopus coucliii, showing the dark-colored, 

 dartlike spades. (Photograph by Thos. Mebane Jones.) 



and forest-inhabiting frogs and toads have a smoother skin than 

 species which live in drier places. Burrowing frogs and toads, such 

 as the spadefoot toad, Scaphiopus, also have thin, smooth skins, 



