382 JACQUES LOEB AND F. W. BANCROFT 



months after metamorphosis. It would seem, then, that in Rana 

 sphenocephala, which is a southern species, sexual differentiation 

 and sexual maturity set in a little more rapidly than in Rana 

 esculenta. 



It is obvious that further observations are needed to determine 

 definitely the sex of parthenogenetic frogs. 



I 



