8 BOTANICAL GAZETTE [JANUARY 
When the male cell enters the archegonium it consists of dense 
cytoplasm inclosing a solid and compact nucleus. It rapidly 
enlarges before actual contact with the egg nucleus. At the time 
of contact there is much more nuclear sap and apparently rather 
less chromatin. The condition of the nucleus before contact is 
fairly well shown in fig. 16, showing (above the 2-nucleate pro- 
embryo) the second male cell. This male cell is beginning to 
degenerate and is in consequence somewhat more dense and homo- 
geneous than the functional one. It should be compared with 
figs. 11-15. The egg nucleus contracts instead of expanding. 
It also appears to lose much of its chromatin. A comparison of 
figs. 11-15 with fig. 7, all photographed at the same magnification, 
will make this point clear. At the time of fusion the two nuclei 
are not very different in size. It is rather difficult to obtain an 
accurate notion of their comparative sizes because of the markedly 
different shapes. The egg nucleus usually remains round (figs. 
11-14), while the sperm nucleus becomes concave on the side 
pressed against the egg nucleus. In consequence, it spreads out 
laterally so as to cover a third to a half of the surface of the egg 
nucleus. Its change of shape is accompanied by a loss of nuclear 
sap, but probably not of chromatin. The two nuclei remain in 
contact for some time, as shown by the frequency of this stage in 
my preparations as compared with some other stages. The manner 
of fusion is shown in fig. 15. A perforation between the two nuclei 
is formed and the gap stretches until the contents of the two nuclei 
are contained in a common cavity. The nuclear membrane of 
the fusion nucleus thus consists of parts of both the sperm and egg 
nuclear membranes. 
The chromatin of the two nuclei enters the fusion nucleus in 
the form of coarse or fine nets. Fig. 15 shows the chromatin as 
fine granules distributed evenly throughout the two nuclei. Fig. 13 
shows granules arranged in series that might easily correspond to 
individual chromosomes. Other preparations show various gra- 
dations between these two extremes. Whether the two masses 
remain separate, as is said to be true in Pinus (5, 9a, 14, 15) and 
some other gymnosperms, could not be determined from the avail- 
able material. No preparation showing the fusion nucleus after 
