74 



HYPOPHYSIS->OVARY->-OVIPOSITOR 



II 



Without the hypophysis, growth of the ovipositor cannot 

 take place. The hormone from the hypophysis does not affect 

 the ovipositor directly, but acts on the ovary, resulting in the 

 formation of corpora lutea, and secretion of the hormone 

 (oviductin), which stimulates growth of the ovipositor (Fig. 

 49). Oviductin is not identical with progesterone. The 

 formation of the gonadotrophic hormone takes place in the 

 "gonadotrophic zone", which is situated in the pars anterior, 

 and the process is rhythmical, as indicated by the regular 

 alternation of acidophilia to basophilia. 



2. In accordance with the findings of Charipper (1937) 

 the hypophysis of the fish possesses the four familiar lobes 

 (Fig. 5 9 A), and thus conforms to the general basic plan of 



■o periphery 



Fig. 59. Schematic 



reduction of the 

 different pituitary 

 types found in 

 vertebrates. 



Fig. 60. 



neurocrinia 

 gland, cell secret. 



Diagrams showing haemo- and neurocrinia in 

 Rhodeus amarus. 



