454 Sargant. — T he Formation of the 
if the fission had already taken place they should have been 
about forty-eight h The discovery of earlier intermediate 
forms, such as that drawn in Fig. 3, and of rather later figures 
in which the chromosomes though still directed towards either 
pole show clear longitudinal fission (Fig. 5), confirmed the 
conclusion that the stage in question (Fig. 4) occurs before 
the formation of a typical nuclear plate. The ribbon-like 
character of the segments in Figs. 3 and 4 is marked. 
The chromosomes when arranged to form the nuclear plate 
(Fig. 6) lie in a plane perpendicular to the axis of the spindle. 
The separation of their segments has begun. Bundles of 
spindle fibres are attached to each segment near one end, 
and the segments separate exactly as if they were pulled 
apart by ropes fixed at this point (Figs. 6 and 7). Each 
segment as it nears the pole is seen to be hook-shaped 
(Fig. 7). In Fig. 8 the daughter nuclei are seen to be fringed 
by the longer legs of the hooks not yet drawn up into them. 
The daughter nuclei at first consist of naked coils of 
chromatic ribbon. By degrees the coils open, a nuclear 
membrane is formed, nucleoli appear, and the chromatic 
ribbon lengthens. The nuclei ultimately pass into the resting- 
stage by a series of changes which I am unable to decipher. 
The cell-plate and cell-wall are formed in the usual way. 
Oogenesis. 
While the nucellus is still a mere hump on the placenta, 
its tissues contain numerous dividing nuclei. The nucleus 
of any hypodermal cell occupying a fairly median position 
may be the ancestor of a future embryo-sac nucleus. All 
these divisions however conform strictly to the vegetative 
type. The spindle figures differ somewhat in shape, in some 
cases being equally developed all round the axis of the 
spindle (Fig. 9), in others flattened as is usual among integu- 
ment nuclei (Fig. 4). In one such case I was able to count 
1 It is extremely difficult to count the chromosomes is a small spindle figure 
with perfect accuracy. I have uniformly found about twenty-four chromosomes in 
nuclei from vegetative tissues of Lilium Martagon . 
