13' 



CYCLIC CHANGES 



IV 



oogonia 



12 2 months 



Corp. lutea 

 Bidder 



months 



•ig. 95. Relation between the development of spermatogones, testis and 

 the organ of BIDDER in Biifo biifo during the cycle. 



the organ of BIDDER and the oviduct in the sexual-endocrine 

 organization of the male toad by assuming that the rudi- 

 mentary ovary and its accessory oviduct constitute a unit, 

 which behaves independently of its possessor determined as 

 being a male; a unit, therefore, which forms corpora lutea 

 in the organ of BIDDER, and, as an oviduct, reacts to the 

 hormone thereof. The organ of BIDDER and the male oviduct 

 may be regarded as vestiges rather than as an integral func- 

 tional part of the sexual-endocrine system. (See experiments 

 of WiTSCHI and others on Bidder's organ and sexual dif- 

 ferentiation of Amphibia). 



i. The pituitary influence on the sexual-endocrine organi- 

 zation of Bufo bufo. 



Both in the testis and in the genuine ovary the greatest 

 emission of gametes takes place during the breeding season. 



