GYMNOSPERMS, 151 
cell (body cell) (Fig. 60, E). ‘In this figure the division is in the 
telophase, the two daughter-nuclei being still connected by the con- 
necting fibres. Owing to the crescent shape of the cell the spindle 
lies at an angle to the major axis of the prothallium, the lower nucleus 
being crowded to one side by the position of the first prothallial cell, 
while the upper nucleus occupies a central position in the upper half 
of the cell, which, when the wall is formed, will become the genera- 
tive cell (body cell, central cell); The lower nucleus becomes the 
nucleus of the stalk cell. Fig. 60, F, represents the next stage in 
which the division is complete. A distinct transverse plasma mem- 
brane is formed just above the apex of the first prothallial cell which 
is almost entirely surrounded by the stalk cell. It is clear that should 
the plasma membrane separating the generative from the stalk cell be 
very delicate and somewhat obscured, the nucleus of the stalk cell 
would appear to be forced out to one side. For this reason it seems 
possible that the plasma membrane separating stalk and generative 
cells in Cycas was overlooked by Ikeno. In Gzz&go the first prothal- 
lial cell, which according to Webber is also surrounded by the stalk 
cell, was considered by Hirase (’98) to be strands of cytoplasm in the 
second prothallial cell. Miyake (’02), who has also examined Ginkgo, 
confirms the observations of Webber. 
At the stage of Fig. 60, F, according to Webber, the nucleus of the 
generative cell is 9.79 » in diameter, that of the stalk cell 7.12 «4, while 
the first prothallial cell is 8.9 4 in diameter. The entire prothallium 
is 29.37 « long by 16.91. wide. 
Neither during the division of the second prothallial cell into stalk 
and generative cell nor for some time afterward was anything observed 
in the cell in connection with the spindle, or elsewhere, that suggested 
a young blepharoplast. It is not until the generative cell has increased 
considerably in size that the first traces of the blepharoplasts were recog- 
nized. At first each blepharoplast consists of a small, deeply staining 
granule, from which several filaments of kinoplasm radiate, following 
the meshes of the cytoplasmic reticulum (Fig. 60, G). ‘* The central 
granule (Webber, ’o1, p. 31) does not seem to be different in sub- 
stance from the radiations—stains the same and shows no differentiation 
of structure. In this stage it is only a half micron in diameter or less, 
and seems to be scarcely more than the point of the crossing of the 
filaments of kinoplasm. These granules are located in the cytoplasm 
about halfway between the nucleus and the cell-wall. Two are 
formed in each central cell at the same time and apparently inde- 
pendently. They are commonly located on the opposite sides of 
