1897 | LIFE HISTORY OF LILIUM PHILADELPHICUM 437 
be determined by studying the subsequent divisions. If there 
is no such subsequent reduction of granules then it would logi- 
cally follow that the granules must fuse during the union of the 
sex nuclei. Otherwise the new sporophyte would contain twice 
the number of chromatin granules that the old one did. 
This splitting of the chromosome first longitudinally and 
then ‘tranversely, it will be seen, really amounts to the same 
thing as though the original chromosome were divided into four 
parts, and corresponds to the so-called “tetrad” stage reported 
by the zoologists. The word tetrad, however, could not properly 
be applied here, since a true tetrad does not appear. 
After the chromosomes have collected about the poles of 
the spindle and are beginning to form the daughter skeins, cyto- 
plasmic radiations, similar to those seen around the mother 
nucleus at the time when the micronucleoli were carried out 
into the cytoplasm, appear, and the micronucleoli often seem to 
be attached to them (fig. 37). Whether these radiations are 
organized from the centrosomes at the poles, as might seem 
possible from fig. 38, or are the same as those which surrounded 
the mother nucleus during the migration of the micronucleoli 
into the cytoplasm, I could not determine. It might be that they 
-Temain constantly in the cytoplasm during metakinesis, and only 
Separated somewhat into twe parts. As the daughter nuclei 
become more complete, the micronucleoli collect around them 
and begin to enter into the nuclei (figs. 39, go). As they enter 
the nuclei and fewer are left in the surrounding cytoplasm, the 
cytoplasmic radiations become less distinct, and they finally dis- 
appear altogether when the nucleoli have all entered the daughter . 
nuclei (Figs. 40-43). The micronucleoli as they enter into the 
nuclei build up new daughter nucleoli by a continuous process 
of aggregation and fusion (jigs. 40-43). 
During the divisions of the two daughter nuclei which pro- 
_ duce the four-celled embryo sac, the nucleoli act in exactly the 
_ Same way as has been described for the first division, and the © 
_ Same kind of cytoplasmic radiations arise (figs. 44-46). In the © 
Mitisions which a the embryo sac, the same lace was 
