FROGS AND THEIR RELATIVES 



115 



C, egg con- 



A, eggs before B, eggs after they taining young D, young tadpoles attaching 

 they are laid are laid tadpole themselves to a plant 



t 



E, young tadpole with ex- F, young tadpole with 



ternal gills internal gills G, young tadpole with hind legs 



H, tadpole with webbed 



feet J> tadpole with legs and arms 



FIG. 84. Life history of frog. 



young frog 



A, one-ce'lled stage B, two-celled stage C, four-celled stage D, eight-celled stage 



, sixteen-celled 

 stage 



F, thirty-two 

 celled stage 



G, sixty-four 

 celled stage 



FIG. 85. Cell division in a frog's egg. 



H, many-celled 

 stage 



