1918]. - WENIGER—FERTILIZATION 263 
Observations 
Upon leaving the pollen tube the male nuclei retain their coiled 
shape for some time. The egg nucleus (fig. 1), with chromatin in a 
resting condition before the arrival of the male nucleus, remains 
in this condition, while the male nucleus lies in contact with it. 
Stages can be found abundantly in which the male nucleus has 
penetrated the egg and lies adjacent to the egg nucleus, and in 
which the chromatin of the former is in an early prophase (fig. 2), 
or spireme stage (fig. 3), while the chromatin of the latter more 
lightly staining nucleus is in the resting stage. The male nucleus 
is more or less curved around one side of the egg nucleus and usually 
measures about 9 uw at its short diameter, while the spherical egg 
nucleus is 10-12 uw in diameter. Soon the male nucleus becomes 
more rounded, as is shown in fig 4, where the chromatin in both 
nuclei is still in the same stage as in fig. 3. 
The chromatin of the egg nucleus is then formed into a spireme 
(figs. 5, 6); but this spireme was never found to stain as densely 
or become as regular as that of the male nucleus. —The membranes 
of the 2 nuclei seem still to be in contact at this stage. No fusion 
of the spiremes takes place, but each is segmented into chromo- 
somes independently. This account agrees with that of GUIGNARD 
for Lilium Martagon, where no fusion takes place between the 
chromatic elements of the 2 nuclei. 
In the gymnosperms investigated the separate groups of chro- 
mosomes formed from the male and female spiremes respectively 
become oriented on separate spindles, and then the 2 spindles fuse 
during the metaphase. Whether or not this is true for Lilium 
has not been determined. The entire process of fertilization in 
Lilium is an exceedingly rapid one, since the time elapsing between 
the discharge of the male nuclei and the formation of the 2-celled. 
embryo is probably not longer than 8 hours. Since the contact 
stage of the 2 nuclei in the prophases of the division is of such rela- 
tively common occurrence in preparations made, it would seem that 
it occupies the greater part of this time, and that for this reason the 
actual division of the fertilized egg is a very difficult stage to obtain. 
One very favorable preparation shows this division, with some of 
the chromosomes still on the equatorial plate and others already 
