THE AMPHIBIA 



301 



tional respiratory organs. Salamanders in general feed on 

 worms, insects, crustaceans, and other small animals. 



Several of the salamanders have legs that are very small or 

 else absent altogether. One of these, known as the " mud eel " 

 (Fig. 1 So), inhabits the ponds and rivers of the South from 

 Texas to North Carolina. It burrows in the mud of ponds and 

 ditches or swims by undulations of the body. The fore limbs of 



Fig. 179. — Tiger salamander. (Photograph of living animal furnished by 

 American Museum of Natural History.) 



the mud eel are very small and the hind limbs are entirely 

 lacking. 



Tailless Amphibians. — The tailless amphibians, the toads 

 and frogs, are much more numerous than their tailed relatives. 

 They are all very similar in structure, although the different 

 species vary in size and general appearance. In North America 

 there are about fifty-six species. Some of them (toads and tree 

 frogs) live on land, but others (water frogs) spend a large part 

 of their time in the water. The terrestrial species possess only 

 slightly webbed hind feet or no webs at all. They crawl or hop 

 on land, burrow in the earth, or climb trees. Dark, moist hiding 

 places are usually required, and most of them take to water only 

 during the breeding season. 



