318 



COMPARATIVE ZOOLOGT. 



Proteus of Austria, and Necturus of the eastern United 

 States. 



2. Vrodela, as the aquatic Newts and land Salamanders, 

 always have four limbs, but the gills rarely persist in the 

 adult stage.'" 



3. CcBcilia have neither tail nor limbs, a snake-like form, 







F[G. WS.— Proteus angwinus. Earope. 



minute scales in the skin, and well-developed ribs. They 



are confined to the tropics. 



4. Anura include all the well-known tailless Am- 



phibians, as Frogs 

 and Toads. They 

 have a moist, naked 

 skin, ten vertebrae, 

 and no ribs. As they 

 breathe by swallow- 

 ing the air, they can 



be suffocated by holding the mouth open. They have 



Fio. 296 — Red Salmnander (Paeudotriton ruber). 

 United States. 



