CALLIPELTIS CUCULLARIA 29 
More than one embryo-sac may sometimes reach perfect devel- 
opment, thus supplying the conditions for false polyembryony. 
This, however, has not been observed. 
The movement of the megaspore down the micropylar canal is 
accompanied by histolysis of the endodermis, the cells of which 
degenerate and collapse. The contents of the cells are disorgan- 
ized and become deeply staining. It is to be noted that the nu- 
cleus is preceded in its course by a part of the cytoplasm, while 
the nucleus itself travels unusually near, or along the side of the 
cavity formed and some little distance back from its apex )۸ 5, 
jig. 6). The amount of cytoplasm is now not great, nor does it 
increase markedly in amount until the complement of embryo-sac 
nuclei is reached. The cells of the egg apparatus, as soon as they 
are cut off, become rapidly different in character from the rest in 
attaining greater density. Their final character is reached at 
about the time of fusion of the polar nuclei or somewhat later. 
The synergids then are vacuolated at their free ends, while the 
egg-cell has a vacuole at its narrow basal end. The fusion of the 
polar nuclei occurs near the middle of the endosperm cavity (pl. 
5, fig. 8) and is followed by a movement of the resultant nucleus 
toward the egg-cell with which it lies in contact till its first di- 
vision. Meanwhile the cytoplasm loses its vacuolated character 
and becomes more dense and gorged with food material, consist- 
ing, in large part, of starch. The whole endosperm-cell becomes 
more rounded also. 
THE ANTIPODAL CELLS 
When the fusion of the polar nuclei is taking place the anti- 
podal nuclei have arranged themselves in their definitive positions, 
two of them close together, each with its proper mass of cytoplasm 
which is thin and vacuolated, and the third some distance away in 
the narrowing end of the somewhat irregular cavity formed by the 
megaspore in its migration (A. 5, fig. 9). The cytoplasm of this 
latter antipodal cell is at first extremely scanty, so much so that it 
cannot be detected with a high power except near the nucleus. The 
two small antipodals secrete cell walls and remain in a normal 
condition for some time during the development of the embryo, 
Their cytoplasm becomes more dense from the time they are first 
