§ 3 



SEXUAL CYCLE OE LEBISTES RETICULATUS 



133 



elevation-state and is comparable with the corpus luteum 

 effect in pregnant females. The time of maximum elevation 

 and that of the maximum number of pre-ovulation corpora 

 lutea coincide (Fig. 93). No doubt, oviductin acts on the 

 follicles, the ovary wall and the genital aperture, causing 

 hypertrophy of the ovary, and distention of the oviduct and 

 genital aperture, resulting in the elevation-position, which 

 provides the conditions necessary for copulation. This eleva- 

 tion-cycle may repeat itself several times. It precedes fertili- 

 sation and is completed in pro-estrus. The synchronisation 

 of the elevation-position and the formation of corpora lutea 

 is not necessarily due to any direct connexion between the 

 two, but may result from various causes. Jaski assumed 

 that, through the resorption of large ova and growth of 

 smaller ova, a shift of the centre of gravity of the body took 

 place, which he supposed to cause elevation. This mechanical 

 explanation, however, proved to be incorrect, as the follicular 

 derivatives, described by him as being "transformed follicles", 

 were merely calyces of primiparous females. 



To summarize : In the Lebistes female, both preparation 

 for pregnancy and pregnancy itself are accompanied by the 

 formation pre-ovulation corpora lutea; the calyces nutriciae 

 secrete embryotrophe, and in pro-estrus, the elevation cycle 

 alternates with the pregnancy cycle. 



Fig. 93. Correlation between elevation and corpus luteum formation in 

 Lebistes reticulatus. 



