450 Ferguson , — The Development of the Egg and 
• rapid condensation and localization of the chromatic sub- 
stance ’ ; but he is inclined to believe that ‘ a considerable 
portion of the chromatin breaks down at this time into limn.’ 
It would appear that the prominence of the achromatic 
reticulum in the conjugating nuclei of Pinus results from both 
these processes. For, while there is always a large quantity 
of linin in the egg-nucleus and a comparatively small amount 
of chromatin, the size of the chromatic spirem, when formed, 
seems disproportionate to the entire bulk of the chromatin 
earlier existing in the nucleus. 
The chromatin continues to separate out from these nuclei 
until a spirem, studded with irregular granules, lies just within 
the wall of the sperm-nucleus, and a similar one arises directly 
below in the egg-nucleus. Frequently the cytoplasm caught 
between the two nuclei collects into spherical masses ; between 
these spheres of cytoplasm the membranes of the nuclei come into 
close contact (Fig. 52). Very soon the spirem of each nucleus 
becomes coiled and regularly moniliform ; and the chromatic 
band of the sperm-nucleus takes up a position along that side 
of its nucleus which is nearest to the spirem formed in the 
egg-nucleus. At this time delicate, minutely granular threads, 
some of which pass from nucleus to nucleus, appear in the 
regions of the two chromatic spirems. The rest of the achro- 
matic contents of these nuclei is largely transformed into long, 
comparatively heavy threads, which are furnished with 
innumerable granules. The two nuclei are still perfectly 
distinct ; the nucleolus of the egg-nucleus may persist at this 
stage ; and the nuclear membranes are yet present, although 
they are very irregular in outline, and have given way at 
several points (Fig. 54). The nucleolus is not always present 
at this time, but nucleolus-like masses, which from their 
position are evidently derived from the egg-nucleus, may be 
present as late as the telophase of the division. Delicate, 
granular fibres continue to arise in the regions of the two 
spirems ; the coarser, achromatic threads of the nuclei become 
finer in structure, and extend in all directions towards the 
forming spindle ; and the nuclear membranes fade entirely 
