80 ZOOLOGY. 



quickly develop a membranous margin to the body, 

 especially round the tail, which consequently forms a 

 sort of oar. Meanwhile internal gills develop, and 

 the external ones disappear. The larvae are now fish- 

 like (" tadpoles "). The limbs quickly grow out, the 

 lungs develop, the tail shrivels up, and the animal 

 leaves the water. Even the adult, however, lives 

 among damp surroundings. In the adult state the 

 Amphibians feed on insects, worms, and snails ; many 

 species are exceedingly useful owing to this. 



Amphibians are divided into two orders, the Urodela 

 (Newts, etc.) and the Anura (Frogs and Toads). To 

 the first belong the Great Crested Newt (Triton cris- 

 tatus) and the Common Newt (Lissotriton tceniatus). 



Fig. 61.— Common Frog (Sana Umporaria). 



Examples of the Anura are the Edible Frog (Rana 

 escwlenta), the brownish Common Frog (iJ. temporaria, 

 Fig. 51), the Common Toad (Bufo vulgaris), and the 

 Natterjack (B. calamita, Fig. 52). 



Both frogs and toads do good by devouring many 

 noxious insects, and also, in particular, snails. Toads 

 are often kept in greenhouses for this purpose; and 



