554 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and after impregnation in the embryo-sac of a variety of the cultivated 
wheat. The following are the more important results. 
The mother-cell of the embryo-sac divides into four superposed 
daughter-cells, separated from one another by strongly swollen septa. 
The terminal one of these four cells develops into the embryo-sac, 
while the remaining three become gradually disorganised. It is rare to 
find in the embryo-sac of Triticum only three antipodals ; usually one of 
the three divides into a very large number, apparently by direct division. 
While the secondary nucleus of the embryo-sac is being formed, the 
membranes of the synergids and of the ovum-cell become somewhat 
thicker ; the former differ from the latter in their more elongated form. 
In the divisions which take place in the pollen-mother-cells, it 
appears certain that the greater part of the spindle-fibres are derived 
from the surrounding protoplasm. 
In the vegetative portion of the inflorescence the number of chromo- 
somes in a nucleus is usually 16, though as many as 24 have been 
observed. In the nucleus of the mother-cell of the embryo-sac and in 
the pollen-mother-cells there are only 8. In the fertilised ovum-cell the 
normal number of 16 is again attained. 
The object of the remarkable increase in the number of antipodals 
appears to be to supply nutrient material to the endosperm rather than 
to the fertilised ovum-cell. 
Antherozoids of Zamia.* — Mr. H. J. Webber announces the discovery 
of motile antherozoids in Zamia integrifolia , and describes a peculiar 
structure of the pollen-tube. 
After the pollen-grain has germinated, there are found in the pollen- 
tube, near its basal end, two cells, one in front of the other. The pos- 
terior of these cells is spherical or slightly elongated. The nucleus of 
the original cell has divided into two, one of the daughter-nuclei forming 
within the parietal utricle a new and wholly distinct utricle which 
delimits a cell lying entirely within the mother-cell, and surrounded on 
all sides by a layer of protoplasm of nearly uniform thickness. The 
anterior is much larger than the posterior cell, and is provided with two 
small spherical organs, situated at the opposite ends of the nucleus, 
outside the nuclear wall, and somewhat resembling centrosomes. 
Each of the daughter-cells formed by the division of the generative 
cell develops into a motile antherozoid, two being thus formed in each 
pollen-tube. They are encircled by a spirally arranged band of cilia 
developed from the centrosome-like body. The membrane formed by 
the wall of this body in its disintegration forms a band lying free in the 
cytoplasm of the cell. It becomes greatly extended in length, and forms a 
spiral band or ribbon with five or six coils. On the outer side of this band 
are very numerous protuberances which develop into the motile cilia of 
the mature antherozoid. The mature antherozoids pass into the arche- 
gone through a rupture in the end of the pollen-tube, the watery 'contents 
of the tube supplying a drop of water in which they can swim. They are 
of very large size, visible to the naked eye, 258-332 /x by 258-306 /x. 
There is no free tail. The nucleus is very large, and is surrounded on 
all sides by a thin layer of cytoplasm. The motion of the antherozoids 
* Bot. Gazette, : xxiii. (1897) pp. 453-9; xxiv. (1897) pp. 15-22 (1 pi. and 
5 figs.). 
