Fertilization in Pinus Strobus. 441 
invariably in the form of (J’s or Vs* Blackman states that 
they are straight rods, but he does not so figure them. The 
cell-plate, during the early stages in its formation, lies midway 
between the developing nuclei, but when the daughter-nuclei 
are fully formed the nucleus of the oosphere is, as a rule, 
farther removed from the cell-plate than is the nucleus' of the 
ventral canal-cell. It is very early evident that the cell-plate 
consists of two layers. As Chamberlain (’ 99 ) has shown, the 
lower portion of the spindle at this time is ordinarily convex, 
while the part within the ventral canal-cell is concave (Figs. 30 
and 32). 
I was able, in several preparations similar to that illustrated 
in Fig. 23, to count the number of chromosomes, and twelve 
or thirteen were found in both groups instead of eight as 
counted by Dixon (’ 94 ). 
The Ventral Canal-Cell. 
As a rule the nucleus of the ventral canal-cell never pre- 
sents a normal appearance, but shows signs of disintegration 
very early in its history. It is doubtful, in some cases, if 
a nuclear membrane is ever formed, and there are probably 
instances in which fusion of the chromosomes never takes 
place at all (Figs. 25 and 27) ; although Blackman, judging 
from such an appearance as that shown in Fig. 29, holds the 
latter condition to be impossible. The nuclear membrane, 
when present, very soon breaks down, and the chromatic 
substance becomes scattered throughout the cell (Figs. 30-32). 
This cell, immediately preceding and at the time of fertiliza- 
tion, ordinarily forms a deeply staining mass which lies just 
beneath the neck-cells and above, but in contact with, the 
egg (Figs. 12, 32, 40, and 42). The nucleus of the ventral 
canal-cell in Pinus austriaca has twice been observed to 
« 
approximate in size that of the egg nucleus (Fig. 29), but 
in a study of several thousand archegonia of Pinus Strobus 
no instance has been found in which these two nuclei were 
similar in form ; the nearest approach to a normal nucleus 
