AMPHIBIOUS VERTEBRATES. 201 
Fic. 243.—Metamorphosis of the frog. ¢, eggs; 1, tadpoles just out of the 
egg; 2, with outside gills; 3, with gills hidden, and beak-like mouth ; 4, 
hind-legs appearing; 5, all legs grown, but fish-tail remaining ; 6, put- 
ting on frog appearance, tail being absorbed ; 7, young perfect frog. 
Toads (4ufonide).—The toads in the adult form are 
terrestrial, the toes are webbed, and the skin generally 
covered with warty protuberances. The eggs of Pelobates 
are deposited in the water in a loop. The male of the 
Alytes of Europe winds the eggs about its body in strings, 
and goes into the water, remaining until the young appear. 
The spade-foot is noted for its sudden appearance in cer- 
tain localities. It remains but a day or so in the water, 
