1 1 o FOLLICULAR DERIVATIVES IN VERTEBRATES III 



§ 7. THE SIGNIFICANCE OF THE CORPORA LUTE A AND OTHER 



FOLLICULAR DERIVATIVES IN THE SEXUAL-ENDOCRINE 



ORGANIZATION OF VERTEBRATES 



Apart from morphological data relating to the development 

 of follicular derivatives we are chiefly concerned here w^ith 

 their significance within the sexual-endocrine organization of 

 the particular species with which we are dealing. With the 

 exception of what we already know concerning the post- 

 ovulation corpus lutcum in mammals, however, we are 

 unfortunately still at the beginning of our studies, and we 

 can only guess at the real extent of their importance. Only 

 by future experiments will it be possible to obtain con- 

 firmation of such hypotheses or their replacement by more 

 correct views. 



a. The atretic follicular derivatives probably produce a 

 sexual hormone whose function is to maintain the adnexa 

 of the gonad, during periods of little sexual activity, and to 

 bring these tissues into such a condition that a response may 

 be made when the moment of heightened activity has come. 

 The preparation of the adnexa in puberty is an example of 

 this. It is accompanied by a most intensive formation of 

 atretic follicular derivatives. These atretic phenomena are 

 chiefly limited to birds and mammals (Fig. 76A). 



/5. The significance of the pre-ovulation corpus luteum. 

 BrETSCHNEIDER and DUYVENIE DE WiT (ig^y-'^g-' 40) have 

 shown that, in the bitterling, the hormone of the pre-ovu- 

 latio corpora lutea is responsible for the growth of the ovi- 

 positor. They have called this hormone "oviductin", and 

 have succeeded in preparing it from the ovary of another 

 fish (Lophius). With this it was proved that in the ovary 

 of fishes, after stimulation from the hypophysis, a sexual 

 hormone is formed which acts upon the oviduct, and that 

 this hormone is produced in follicular derivatives formerly 

 regarded as degenerative formations. With this the bridge 

 was laid between Anamnia and Mammalia, and a similarity 

 to the sexual-endocrine organization of vertebrates demon- 

 strated. In both fishes and amphibia the pre-ovulation corpus 



