of Some Embryo-sacs. 83 
dividing first (Plate XI, Fig. 6). The inner quadri-nucleate 
cell now becomes passive and after a time undergoes a slow 
degeneration, which becomes complete about the time of 
fertilization. 
After a short resting phase the quadri-nucleate embryo-sac 
grows rapidly, and by the degeneration of the three cells first 
formed from the archesporium, as well as the surrounding 
nucellar cells, it comes to lie against the epidermis of the 
nucellus. By division of each of its nuclei, the quadri-nucleate 
embryo-sac at length shows eight nuclei. The eight nuclei 
of the embryo-sac now arrange themselves in the typical 
manner (Fig. 7). By the time the embryo-sac has become fully 
developed the ovule has become completely anatropous, and 
the primine and secundine have grown so as to completely 
cover in the nucellus. 
The question now arises as to the nature of the quadri- 
nucleate cell next the embryo-sac. For some time it appeared 
to the writer that this cell might represent a sporocyte which 
had divided into four spores. Accordingly if such were the 
case, one would be led to suppose that the embryo-sac repre- 
sented two sporocytes which were not separated by a cell 
wall. This view seemed to find some support in the observa- 
tion by Mann of a partition wall in the embryo-sac of Myosu- 
rus, and in the possibility of the fertilization of the synergids 
as described by Dodel and Overton in /ys and Lzium. A 
more careful study of its relationship, however, seems to 
militate against the hypothesis that the embryo-sac contains 
two sporocytes. In its development, the Angiospermic 
embryo-sac agrees, on the whole, pretty closely with that of 
Gymnosperms. Further, the reduction division, which so far 
has been found to take place during spore formation, appears 
to occur in the formation of the embryo-sac and its neighbor 
quadri-nucleate cell. Accordingly it seems probable that the 
quadri-nucleate cell is an embryo-sac or macrospore which 
only goes part way in its development. 
