8 
H. marshall ward. 
cloudy and prepare for degeneration, and final disappear. 
Very shortly the remains of the Gehiilfinnen form a lens- 
shaped cap between the embryo and the apex of the sac, 
while the decaying antipodal mass presents a similar appear- 
ance below (cf. figs. 18 — 22 )} In fig. 21 the appearance of 
four nuclei in the antipodal mass — and a similar condition of 
things is vaguely indicated in other cases, as fig. 19 — suggests 
that the union of a fourth nucleus with one from above to 
form the embyro-sac nucleus has not occurred, or if so, a 
further division of the antipodal cells has taken place. 
The nucleus of the elongated embryo-cell now divides, and 
a wall appears between the new nuclei cutting it into an 
upper and a lower cell. This horizontal lamella is thin and 
sharply marked, and is nearly or quite perpendicular to the 
long axis of the embryo. Each cell is full of fine grained 
dark protoplasm, and its nucleus is very large, spherical, 
and bright, and contains one or two brilliant nucleoli 
(fig. 18.) On account of the different fates of these two cells 
we must distinguish them from the first ; the upper one 
becomes the pro-embryo or suspeiisor, and has but a tran- 
sient existence ; the lower produces the true embryo. 
Each nucleus repeats the process of division exactly as 
before, and we have the embryonic body divided by two 
more walls parallel to that first formed (6g. 20 ), and already 
is established a physical diflference between the embryo and 
pro-embryo, the latter being narrow and tapering somewhat, 
and having difiluent thick walls, while the embryo rapidly 
becomes stouter and more globular in accordance with the 
distribution of its thin sharply marked cell-walls (cf. figures). 
In fig. 19 the wall in the embryo is completed, and two 
large nuclei again rounded off, but that in the pro-embryo is 
only just appearing, its nucleus being fixed in the last stage 
of division prior to the separation of the new nuclei, which 
have already commenced to aggregate at the poles. In 
fig. 20 the process is completed. 
A further difference between pro-embryo and embryo is 
now established, in that the next divisions in the embryo 
are perpendicular to that already formed, whereas in the pro- 
^^embryo all the divisions are horizontal, and parallel to the 
first. In fig 24 the terminal cell of the pro-embryo is com- 
mencing to divide as indicated by the condition of its nucleus, 
while in fig. 27 the second cell has just divided, and the 
last threads of protoplasm are still in contact with the new 
wall. We thus demonstrate that each cell of the pro-embryo 
divides, and its elongation is effected by intercalary growth. 
^ Iji some endosperinous ovules the antipodal cells divide vigorously. 
