SEXUAL CYCLE OF RHODEUS AMARUS ? 



A 



seize mature eggs 



/^ ./®)rriedium-seizcd cggs> 

 mature eggs 



1 3 



I / • \medium seized eggs 

 mature eggs 



f S^Jcorp.lut. 



Fig. 77. Relation between the growth of the eggs, the formation of 

 corpora lutea and ovipositor growth during the cycle in Rhodeus amarus. 



c. Estrus. At the end of April or the beginning of May 

 the first ova are deposited, and after this at intervals until 

 the end of June. From investigations by MeltZER the fol- 

 lowing facts have come to our knowledge. As we have 

 already remarked, development of the ovipositor is complete 

 only when both male bitterlings and mussels are available. 

 It has been proved that the male bitterling secretes a substance 

 into the water which causes the ovipositor to grow (GOEDE- 

 WAAGEN - unpublished). JASKI called the substance, in the 

 case of Lebistes, "copulin"; but without the mussel, growth 

 is incomplete and oviposition never takes place. When, during 

 spawning time, the ovipositors of female bitterlings kept in 



