28 4 Ishikawa.—Studies on'the Embryo Sac 
the case with the synergid nucleus. It may perhaps be the proteid crys¬ 
talloid, though its characteristic reactions could not be brought about by 
chemical reagents, due to the influence of the fixing fluid. It is, however, 
interesting to notice the fact that all transitional forms from a spherical 
vacuole to the crystalloid may be followed ; anyhow those structures may. 
need a further investigation. The occurrence of the crystal in the nucleolus 
has been described by Leitgeb for Galtonia candicans , and later by Digby 
( 16 ) in the same plant, who states that the crystal was probably originated 
from the nucleolus, and appeared to stain with chromatin dyes. Reed ( 56 ) 
is another investigator who found a similar substance in Allium Cepa\ 
according to this author such structures were observed during the develop¬ 
ment of the spireme, at the end of which they disappeared and seemed 
to be stained no longer. Dr. Kuwada personally informed the writer 
that he also found it in the nucleolus of the pollen mother-cell of 
Zea Mays. 
Text-fig. I, 12, is another view of a similar embryo sac, cut at right 
angles to the median line of the embryo sac represented in Text-fig. I, n. 
The whole of the oosphere is represented, but one of the synergids is left in 
another section. Here both the filiform apparatus ( fil ’.) and the indentation 
(ind.) of synergids are also clearly shown. A large vacuole occupies nearly 
the whole space of the egg-cell, in the lower end of which the nucleus lies 
against the cell-wall. Generally the nucleus of the egg-cell is smaller than 
that of the synergid, though such a relation is not well shown in this figure. 
Members of the egg apparatus are clearly separated by a distinct cellulose 
membrane from one another as well as from the wall of the embryo sac. 
The lower end of the oosphere is peculiar in this respect, that it possesses 
neither cellulose nor pectin membrane so far as is indicated by chemical 
reagents. Plasmolysis does not occur in this portion, while it is clearly 
discernible in the remaining part; the lower end may probably be bordered 
by a plasma membrane. As clearly shown in the figure, the apical end of 
the embryo sac is occupied by the synergids, and the egg-cell hangs down 
from a position at a distance below the terminal end of the sac. Spherical 
starch grains were generally found scattered in the plasma sheet of the sac 
as well as in the lower part of the oosphere, but in a few cases they have 
been observed as occurring also in the synergids (Text-figs. I, 12, III, 15 ; 
PL VII, Fig. 9, b). Proteid and glucose were detected in the vacuole of the 
synergid by Habermann ( 25 ), who concluded that such proteid and hexose 
flowed out through the canals of the filiform apparatus, causing a chemotropic 
reaction of the pollen-tube. The absence of starch grains in the synergid 
seems to be correlated with the presence of glucose in the vacuole, the 
glucose being a mere disguise of the starch. 
Among over 500 selected preparations which were closely examined, 
four sections were found in which small rod- or biscuit-formed structures 
