OF THE UNITED STATES 



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frogs, these ova being impregnated by the male at the time of 

 their passage. In due course of time, depending largely upon 

 the temperature, these eggs hatch out the young tadpoles, that 

 pass through various stages to young frogs. These stages are 

 exceedingly interesting to study, and the far-reaching chapter 

 they cover in biology will more than repay the young naturalist 

 who will collect a mass of these eggs, take them home, and, plac- 

 ing them in the proper conditions, watch all the details of the 



Fig. 25. Common Bullfrog. 



One-half natural size. From a photograph by the Author 



development, with a complete treatise upon amphibian reproduc- 

 tion at hand. 



Tadpoles of the Anura subsist upon a vegetable diet, while the 

 adult frog lives upon insects, crustaceans and the smaller fishes. 

 It is said that our common Bull-frog takes about five years to 

 attain its full growth, and its life is supposed to extend to about 

 ten years more thereafter. They have a host of enemies; as 



