1900] DEVELOPMENT OF THE EMBRYO-SAC 27 
the other the fibers seem to accomplish the separation. The 
former splitting is only partial, while the latter finally divides 
the chromosome into two V-shaped parts which move at once to 
the poles through the influence of the spindle fibers. This is 
therefore a heterotypic division, and similar to the one occurring 
in the pollen-mother cell. In fact it seems probable that having 
the spindle alone one could not distinguish the two cases, even 
after a careful study of the chromosomes themselves. The num- 
ber of chromosomes was found to be eighteen, and since the 
number counted in the somatic cells was greater than thirty, it is 
evident that reduction takes place at this period. During the 
anaphase of the first division (fig. 5) a definite cell-wall is 
deposited, which divides the original cell into two nearly equal 
parts. 
THE SECOND NUCLEAR DIVISION. 
The nucleus in each of the two daughter cells resulting from 
the first division very quickly divides again, and it so happens 
that the two spindles are formed simultaneously. No cell-walls 
are formed after this division, at least not before the embryo-sac is 
nearly mature. At the stage shown in fig. 8 four nuclei are 
present. The second division spindle was in this case directed 
longitudinally; therefore in the same plane as the first; but this 
is not always the case. Sometimes the axis of the spindle is 
inclined and in fact almost. transverse. The position of the 
spindle, however, seems to be of little importance, since one may 
find the two daughter nuclei during later stages either one above 
the other or side by side. 
The resting stage between the first and second divisions, like 
that in the pollen-mother cell, is very short. The V-shaped 
chromosomes remain distinct and uninclosed by a definite mem- 
brane. The spindle quickly forms, apparently from the sur- 
rounding cytoplasm, and at the same time the chromosomes are 
crowded toward the equator where they arrange themselves in 
a nuclear plate. These spindles were in all cases much less dis- 
tinct than the first one, and appeared in the earlier stages 
