THE THEORY OF SEX 611 



nance, etc., except that he speaks in terms of definite substances 

 instead of symbohc factors. We beheve that we can reach a 

 really good explanation of the life-cycles of Daphnids by omit- 

 ting some of the com])lications of Woltereck's hypothesis and 

 adding to it the simple quantitative conception deduced from our 

 work. This seems especially hopeful at present since Banta^ has 

 very recently communicated the discovery of intersexual strains 

 in Daphni,a. Further discussion had, therefore, better await the 

 details of Banta's work. 



Osborn Zoological Laboratory, 

 Yale University 



" Banta, A. \l. Sex intergrades in a species of Crustacea. Proc. Nat. Acad. 

 Sc, 2, October, 1916. 



