210 A^. M. Stevens 



of the germ cells in the telophase. Other cases- where synapsis 

 is known to occur either before or after synizesis have indicated 

 that the two phenomena have no necessary connection. In a 

 recent paper Miss King ('08) describes a separation of chromatin 

 substances and rejection of masses of deeply staining material 

 from the spireme during synizesis in the oocytes of Bufo lentin- 

 ginosus. Something similar was observed b)' Miss Boring ('07) 

 in connection with the synizesis stage of the spermatocytes of 

 three species of Ceresa (PI. Ill, Figs. 62-67, 82 and 93). In the 

 former case the rejected chromatin substances were observed in 

 the form of nucleoli and also as a deposit on the nuclear mem- 

 brane ; in Ceresa they formed a dense pla te a t the base of the bouquet 

 of short chromatin loops in the synizesis stage, and later became 

 divided up into several dense masses distributed over the inside 

 of the nuclear membrane and gradually disappearing in the later 

 growth stages and prophases of the first maturation division. 

 Buchner also describes a "Chromidial-austritt" during the syni- 

 zesis stages of the oocytes of Gryllus campestris where granules 

 of material staining like chromatin are extruded from the nucleus 

 in the region where the ends of the chromatin loops touch the 

 nuclear membrane ('09, PI. 21, Figs. 119-121). The change in 

 staining quality of the plasmosome in Culex may therefore be 

 regarded as further evidence that the synizesis stage of both 

 oocytes and spermatocytes is probably a period during which 

 some modification of the chromatin occurs preliminary to matur- 

 ation. Whether the rejected material visible in some cases, is 

 waste material or substances which have some function connected 

 with the growth stages of the germ cells, we can only surmise. 



All through the synizesis and growth stages of the spermato- 

 cytes of Culex, there is absolutely no sign of any condensed hete- 

 rochromosomes, only a plasmosome and a spireme, or perhaps 

 three separate spireme threads. When the spireme begins to 

 shorten and thicken one can occasionally be sure that it is not 



- As examples where synapsis occurs before syni'.esis, I might cite from my own work, Photinus penn- 

 sylvanicus and Limoneus griseus ('09, PI. I, Fig. 5-8; PI. II, Figs. 31-38), while in many other species 

 among the Coleoptera synapsis occurs at the close of the synizesis stage as in Chelymorpha argus ('06, 

 PI. IX, Figs. 37-43) and Photinus consanguineus ('09, PI. I, Figs. 23 and 24). 



