36 



CYCLIC CHANGES 



IV 



Fig. 94. Correlation between corpus luteum formation in the ovary and 



in the organ of BIDDER, and development of the oviduct in Bufo bufo 



during the sexual cycle. 



falls rapidly thereafter, so that, in older animals, it may be 

 either rudimentary or absent. Parallel with this is the pro- 

 duction of corpora lutea in this potential ovary, which 

 reaches a maximum just before maturity (Fig. 94 A), after 



