318 
COMPARATIVE ZOOLOGY. 
Proteus of Austria, and Necturns of the eastern United 
States. 
2. Urodela , as the aquatic Newts and land Salamanders, 
always have four limbs, but the gills rarely persist in the 
adult stage. 162 
3 Cceeilia have neither tail nor limbs, a snake-like form. 
Fig. 295 Proteus anguinus. Europe. 
minute scales in the skin, and well-developed ribs. They 
are confined to the tropics. 
4. Anura include all the w 7 ell-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 
Fro. 296—Red Salamander (Pseudotriton ruber). 
United States. 
