VERTEBRATA 



153 



upper jaw, and webbed feet ; toads (Biifo) are higher in 

 rank, and have neither teeth nor fully webbed feet. 



FIG. 131. Bullfrog (Rana). North America. 



The former have been known to live sixteen years, and 

 the latter thirty-six. 



FIG. 132. Proteus anguinus. Europe. 



3. Gymnophiona have neither tail nor limbs nor gill 

 slit, a snakelike form, minute scales in the skin, and well- 



