524 COLLEGE ZOOLOGY 



a complete hand was regenerated in its place (Barfurth). Triton 

 has been observed to regenerate both limbs and tail. The 

 Salientia are apparently unable to regenerate lost parts to any 

 considerable extent, except in the early stages. As a general 

 rule, the younger tadpoles regenerate limbs or tail more readily 

 chan older specimens. There is a distinct advantage in the 

 possession of the power of regeneration, since amphibians no 

 doubt often escape from their enemies with mutilated limbs or 

 tail, but are not seriously inconvenienced by the loss, as new 

 parts rapidly grow out. 



Breeding Habits. — Most Amphibia are oviparous, and their 

 eggs, as in the leopard-frog, are fertilized by the male after ex- 

 trusion. In some of the Caudata and in the Apoda, however, 

 the eggs are fertilized before they are laid. A few species of 

 Caudata bring forth their young alive; for example, the fire 

 salamander, Salamandra maculosa, of Europe. 



Several curious brooding habits have already been referred 

 to; for example, the obstetrical toad (p. 522), the Surinam toad 

 (p. 518), and the dusky salamander (p. 517). The " marsupial " 

 frogs of the genus Nototrema should also be mentioned. They 

 have a permanent pouch on the back in which the eggs develop. 

 These frogs belong to the family Hylidcs and inhabit the tropical 

 forest region of South America. 



Hibernation. — Many Amphibia bury themselves in the mud 

 at the bottom of ponds in the autumn, and remain there in a 

 dormant condition until the following spring. During this 

 period of hibernation the vital processes are reduced; no air 

 is taken into the lungs, since all necessary respiration occurs 

 through the skin ; no food is eaten, but the physiological activities 

 are carried on by the use of nutriment stored in the body; and 

 the temperature decreases until only slightly above that of the 

 surrounding medium. The temperature of all cold-blooded 

 vertebrates — cyclostomes, elasmobranchs, fish, amphibians, and 

 reptiles — varies with the surrounding medium. Frogs cannot, 

 however, be entirely frozen, as is often stated, since death 



