56 HYPOPHYSIS^'OVARY^OVIPOSITOR II 



the vagina, the glandula vesicalis, etc. In the bitterling it 



is only in the hypophysis that administration of a sexual 



\ hormone causes a primary reaction, followed by the secretion 



; of gonadotrophic hormone. Thereby corpora lutea are 



formed, whose hormone (oviductin) stimulates growth of 



the ovipositor. Oviductin is not identical with progesterone, 



since the latter does not affect the ovipositor directly, but 



I only, like the estrogenic and androgenic steroids, through the 



l^ pituitary. 



- It is evident, therefore, from the hypophysectomy, that the 



hypophysis is indispensable to the growth of the ovipositor 



/ after administration of sexual hormones of the estrane, 



) androstane, and pregnane series. In other words, the reaction 



' of the ovipositor of the bitterling originates in the hypo- 



/ physis. 



§ 2. HOMOLOGY OF THE HYPOPHYSIS-LOBES 



a. Material. 



After we had succeeded in determining experimentally the 

 position of the gonadotrophic cells of the hypophysis (Bret- 

 SCHNEIDER and pUYVENE DE WiT, 1 93 9 — I 940) , we were 

 struck by the lack of unanimity, as evidenced in the literature, 

 in the various views regarding the Teleost-hypophysis. His- 

 torically the terminology of the structural details of the 

 hypophysis was based upon the mammalian hypophysis. 

 Stendel (1904), one of the first to give a comparative des- 

 cription of the anatomy of the hypophysis of vertebrates, 

 introduced, for the Teleostia, the term "Uebergangsteil" for 

 a part of the hypophysis which is well defined, but for which 

 he was unable to find a homologue in the mammalian hypo- 

 physis. It was Charipper who, in 1937, homologised the 

 different pituitary lobes, and so discarded the rather vague 

 term "Uebergangsteil". With this the desired unity of 

 nomenclature had been established. Our own research group 

 also took this problem in hand, more especially because the 

 gonadotrophic cells were situated in this "Uebergangsteil". 



