Some Problems of Reproduction: a Comparative Study of ...

38 MAROUS M. HARTOG.
mation of these cells and their position in the mature embryosac
ready for fertilisation ; the dotted vertical lines indicate
successive stages. The symmetrical relation of the eight
cells formed is in no way exaggerated in the figure.
Of the eight cells so formed not one is capable of ulterior
independent development; though it appears from Strasburger's
figures, 1 and those of other authors, that enough
interval is left between the mitoses for the nuclei each time
to resume a resting state. Hence it cannot be the extreme
rapidity of the mitoses that determines the reproductive incapacity
of these cells. The fate of these eight cells is very
different.
(1) The Apical Pair or Synergids, aptly termed Gehiilfinnen
(handmaids) by Strasbiirger, are utilised as the channel
for the transmission of the male pronucleus, sometimes
undergoing a complete degradation into a gelatinous form of
cellulose.
(2) The Upper Subapical Cell is the Oosphere,
destined on receipt of the male pronucleus to evolve into the
Embryo.
(3) The Lower Subapical and Upper Subbasal Cells
conjugate to form what we may term the Endosperm-cell;
this undergoes repeated divisions, appropriating at each more
and more of the parietal cytoplasm of the embryo-sac, till at
length the brood-cells constitute a continuous cellular layer,
the Endosperm, in which the embryo lies, and destined to
destruction as food for the embryo, either during the maturation
of the seed, or later on in the process of germination.
For some time no cell-walls separate the brood-cells, which
thus constitute an apocytium, lining the embryo-sac, and enclosing
a gigantic vacuole which persists in the Coco-nut. When
cell-walls divide up this apocytium, their inner tangential walls
form a continuous lamina, within which remains a layer of
cytoplasm surrounding the central vesicle, 2 just like that of
the gametangium of Botrydium or Acetabularia. Here
1 ' Befruchtung nnd Zelltheilung, 1 &o.
s Bertkold, op. cit., p. 213,