278 



THE THEORY OF THE GENE 



est of zoologists, who have proposed many views as to its 

 possible functions. The most frequent interpretation is 

 that the Bidder's organ is an ovary and the resemblance 

 of its cells to eggs lends strong support to this interpre- 

 tation; but the presence of a Bidder's organ at the ante- 



FiG. 148. 



Toad in third year from which the testes have been removed at 

 an early stage. Bidder's organ has developed into an ovary. In the 

 figure (to the right) the ovary is turned to one side in order to 

 show the enlarged oviduct. (After Harms.) 



rior end of the true ovary in the young female is difficult 

 to bring into accord with the view that in the male the 

 same organ is an ovary, for, if so, the female has a rudi- 

 mentary or perhaps ancestral rudimentary ovary in 

 front, and a functional one behind it. 



The experimental work of Guyenot and Ponse (1923) 

 and of Harms (1923, 1926) shows that when the testes are 

 completely removed from a young toad, the organ of Bid- 

 der develops after two or three years into an ovary with 



