FROGS, TOADS, AND SALAMANDERS 237 



Hibernation. — When the toad feels winter coming on, 

 it digs a hole in the earth with its hind feet — backing into 

 it as it digs — and Ues at the bottom, in a deep sleep, until 

 spring returns. 



Toads with interesting habits. — The Surinam toad which 

 lives in Dutch Guiana, South America, is exceedingly in- 

 teresting because of the remarkable manner in which its 

 eggs are cared for and hatched. Just previous to the egg- 

 laying period, the skin of the back of the female is specially 

 prepared by nature for a remarkable proceeding. It be- 

 comes very thick, spongy, and soft. The eggs are taken by 

 the male toad, and one by one are imbedded in the skin on 

 the back of the female, so effectually that the skin closes over 

 them, and each egg becomes partially encysted and re- 

 tained in a cell of its own. There they remaui until they 

 are fully incubated, the tadpole stage is passed, and a tiny, 

 but perfect toad emerges from the skin of its mother's back ! 

 Therefore, the Surinam toad does not pass its larval life 

 in the water, but in the adult stage it is thoroughly aquatic 

 and has the hind feet webbed (Fig. 165). 



Other Amphibians 



The caecilians. — These are the lowest of the amphibians. 

 They are wormUke in appearance and bear httle resemblance 

 to vertebrates. They have no legs or fins and many of them 

 are bhnd, with the eyes hidden beneath the skin. They 

 inhabit the tropical regions of Mexico, Central and South 

 America, Africa, Asia, and Australia, but none are fotmd 

 in the United States. These amphibians are of burrowing 

 habits and possess strong, solid skulls because they burrow 

 entirely with their heads. 



