12 Art. C— I. Ikedii and Y. Oznki : 



tho first division, bat divido transversely, so that there arise 

 two sets of four parallel chromosomes, the sets soon afterwards 

 to be divided between the resulting two grand-daughter synkarions 

 (fig. 12, d and <:-)• The chromatin contracts into a compact mass 

 in all these four nuclei of a conjugant. In three of them, this 

 mass assumes the shape of a crescent or a comma (fig. 12, /, and 

 fig. 13, //. d. S//1--3), while the remaining one is peculiar in having 



the chromatin mass of a spherical 

 form (fig. 13, g. d. siß). It may here 

 be mentioned at once that the latter 

 is the one which persists as the 

 micronucleus in the ex-conjugant. 

 Now the process of conjugation is at 

 an end, and the two conjugants begin 

 to detach themselves from each other. 

 \ ■' '^'^'^ß^f AVe will now turn our attention 



to the moganucleus in each conjugant. 

 During the early stage of conjugation 

 the moganucleus shows little change in its appearance, except in 

 one important point : that tho granular nuclear plasm has dif- 

 ferentiated into two parts, that is, the majority of the granules, 

 which are only lightly stained with lurmatoxylin, and a few 

 others which lie around the former and are stained very deeply 

 w^ith hœmatoxylin (fig. 2, N). In our opinion, the granules of the 

 former kind represent plasmosomes, while these of tho latter kind 

 consist of chromatin. About tho time wiion tlio micronucleus of 

 tho conjugants has first divided into two (fig. 4), the meganuclear 

 granular plasm begins to contract, leaving a clear space between 

 it and the nuclear membrane. This clear space grows gradually 

 wader {cf. figs. 5 — 9, N), excepting at two opposite ends of the 

 major axis of the ollipitical moganucleus, where the meganuclear 



