576 VERA DANCHAKOFF 



those granules which lie partly outside and partly inside of the 

 nucleus, both parts being flattened against each other and sepa- 

 rated only by the membrane. The smallest chromatin particles 

 of the nucleus appear as thickenings of the membrane (fig. 8). 



The next change in the nucleus is its growth, while its sub- 

 stance becomes still more achromatic and nearly unstainable in 

 my preparations; only under the highest magnification a slight 

 granularity is perceptible. With further development the nu- 

 clear membrane loses its distinct outlines, and there appear in- 

 numerable connections between the cytoplasmic net and the 

 membrane in the form of thin threads. In eggs, of which the 

 nucleus is surrounded by a larger zone of denser basophilic cyto- 

 plasm, these connections appear very clearly (figs. 9 and 11). 

 The substance of the nucleus, on the contrary, remains well 

 separated and different from the cytoplasm; it may resorb sub- 

 stances from the cytoplasm; but once within the nucleus, the 

 resorbed substances do not leave it. 



The amount of chromatin inside the nucleus gradually in- 

 creases, and the granules keep their characteristic position on 

 the inner side of the nuclear membrane for some time. Occa- 

 sionally they cover the whole inner side of the membrane with 

 innumerable small protuberances (figs. 9 and 13); but their dis- 

 tribution, their form and size, even the intensity of their baso- 

 philic reaction may considerably vary. The figures 8, 9, 10, 11, 

 12 and 13 will demonstrate this. Sometimes single chromatic 

 particles grow very rapidly, attain a large size, (figs. 10, 11 and 

 13), and appear as characteristic nucleoli, which, in the normal 

 fertilization, seem to have a more important and definite role. 



As mentioned above, the flowing of the chromatic substance 

 within the parthenogenetic eggs proceeds with great intensity. 

 Around the nucleus (fig. 4), or around parts of the nucleus, (figs. 

 20 and 22), considerable amount of chromatic substance may 

 accumulate. Since the impregnation of cytoplasm by chromatic 

 substance seems to present certain limits, and its further trans- 

 formation and movement is not infrequently hindered, it happens 

 sometimes, that the chromatic substance accumulates around 

 the achromatic parts of the nucleus and here becomes recon- 



