Studies on Regulation. 



49 S 



in a more or less rudimentary condition. In a considerable 

 number of other cases, however, animals were used for experi- 

 ment during the height of the breeding season and the results in 

 these cases are interesting. 



Fig. 28 represents diagrammatically the course of the genital 

 ducts; the female ducts are indicated in broken lines. The 



