THE DErELOPMENT OF THE FROG S EGO 



455 



Postembryonic Development of the Frog. — After reaching 

 a certain stage of development, the em))ryo frog, called tadpole, 



Fig. 411. — A chart showing the correlation between the stage of develop- 

 inent of the frog on successive days and the temperature at which it has 

 developed. From Higgenbottoni. 



begins to develop legs. The hind legs first ajjpear, afterward 

 the fore legs sprout out, and finally the tail begins to wither 

 away, until the form of the four-legged tailless frog (anuran) 

 is fully developed. In the leopard frog, as in the toad, this 



