620 Wisconsin Academy of Sciences, Arts, and Letters. 
resulted from the two divisions of the embryo-sac mother cell. 
The inner of these cells is small, with small, often distorted 
nuclei and the outer cell is at the close of the second division, 
commonly five or six times as large as the inner cell and its 
nuclei are plump and normal. 
The outer binueleated cell grows rapidly and continuously 
to form the young embryo-sac. The inner cell however remains 
approximately the same size as at the time of the homoeotypic 
division and its nuclei become gradually distorted and disor¬ 
ganized, though often retaining their general outlines as late as 
the beginning of the development of the embryos. At that 
time they may be seen as small irregular masses of deeply 
staining material lying near the three antipodal nuclei which 
they greatly resemble. 
When the outer cell has grown to two or three times the size 
it had at the time of the homoeotypic telophase, its two nuclei 
undergo division forming the four celled stage of the embryo- 
sac (Figs. 41 and 42). After a further period of growth 
during which the large central vacuole of the mature embryo-sac 
is finally formed, these four nuclei divide to form the eight 
nuclei of the embryo-sac (Figs. 43 and 44). 
At a stage very shortly after this last division, three plump 
normal nuclei are to be seen in the micropylar end of the em¬ 
bryo-sac and three somewhat distorted nuclei in the constricted 
antipodal end, while the two polar nuclei have begun to ap¬ 
proach one another (Figs. 45 and 46). At a somewhat later 
stage membranes are formed around the micropylar nuclei 
forming an irregular group of cells. There is a great diversity 
in the arrangement of the cells of these micropylar groups as 
well as in the size of the cells which compose them. Appar¬ 
ently they very rarely become organized to form the typical egg 
apparatus. I have seen, very rarely, embryo-sacs which had 
complexes in the outer end of the cell which might be inter¬ 
preted as an egg apparatus. In nearly all the sacs examined the 
cells of the micropylar end were irregular in size, number and 
arrangement, bearing no resemblance whatever to an egg ap- 
