226 



BRANCH CHORDATA 



the immense vocal sacs of the male until they are hatched. A 

 tree frog ( Hylo'des linia'tus) of Dutch Guiana carries its young, 

 which cling by sucking disks, upon its back. The "Surinam 

 toad" (Fig. 186) places the eggs upon the back of the female, 

 where the skin is soft and spongy, during the breeding season. 

 Each egg sinks down and is covered by a jelly-like film. They 

 remain embedded here until the tadpole stage is passed. The 

 pouched frog ( Nototre'ma mar supia' turn) has the eggs stored in a 

 pouch on the back, where they hatch and the larvae develop. 

 The male of the European species {A'lytes obstet'ricans) winds the 



Fig. 186. — Surinam toad, showing young escaping. (From Holder's 

 " Elements of Zoology," American Book Co., Publishers.) 



string of eggs about the thighs and body. A Japanese frog 

 makes a nest on the ground. One in Brazil makes circular nests 

 in shallow water, smoothing and shaping rings of mud and laying 

 the eggs in these cup-like depressions. Many amphibians are 

 viviparous.^ 



Defense. — Almost all amphibians are more or less poisonous, 

 says Gadow. It has been proved that if a quantity proportion- 

 ate to the size of the animal be injected, that the poison secreted 

 by toads, salamanders, and newts will kill mammals, birds, rep- 

 tiles, and fishes. The poison acts upon the heart and central 

 1 Baskett, see "Viviparous Ajnphibians." 



