STUDIES OF THE DEVELOPMENT OF PEPEROMIA HISPIDULA 369 
The early phases of the preparation of these 8 nuclei for the next 
division have not been seen. The late telophases of this mitosis, 
which were seen, show 16 reorganized nuclei, connected in pairs 
by strands, which are evidently spindle fibers, closely like those shown 
in the 8-nucleate stage (figs. 76, 77). When these 16 nuclei are first 
formed, 4 of them lie in a pretty compact group in the micropylar 
pocket of the sac. The other 12 nuclei lie near or below the middle, 
often in 3 distinct groups of 4 each (fig. 81). It is clear from the ar- 
rangement of these nuclei that the 4 at the micropylar end have come 
from the micropylar spore and each of the other quartets from one of 
the other three spores. In a series of thin sections it is not always 
evident that the 16 nuclei are grouped in tetrads, but careful study of 
the series usually shows them to be so. At a slightly later stage of 
development two of the micropylar nuclei are found surrounded by 
denser protoplasm and cell walls, thus forming two cells that fill this 
end of the sac. The larger of these, the egg, has about twice the bulk 
of the second, which is the single synergid. In some cases these two 
cells may lie side by side (figs. 82, 89, 104) while in other cases the 
synergid may lie somewhat above the egg (figs. 84, 88, 98, 102). The 
egg in the mature embryo sac is often 25 long, and has a series of 
vacuoles outside the denser zone of cytoplasm immediately surround- 
ing the nucleus. The nucleus of the mature egg may be 12 in diam- 
eter and has a distinct, rather fine chromatin reticulum and one nuc- 
leolus (fig. 81). The synergid is somewhat similar in organization but 
is usually smaller and has a less dense cytoplasm (figs. 81, 82, 84, 88). 
The remaining 2 of the 4 micropylar nuclei usually move downward, 
at about the time the cell walls appear around the egg and synergid. 
Later these two free nuclei are found close to the other 12 nuclei that 
lie in the lower half of the sac. In a few of the cases all four of the 
micropylar nuclei were still lying in the pocket after fertilization had 
occurred. Cell walls could not be seen about them and their exact 
origin and relation to each other could not be made out (fig. 87). It 
is of course conceivable that one or more of these nuclei may have 
come in from the pollen tube. 
These 14 nuclei of the lower end of the sac at first lie in one or two 
groups in the peripheral sheet of cytoplasm that surrounds the single, 
large, central vacuole (figs. 80, 83). Later the cytoplasm becomes 
more abundant and the vacuoles smaller, more numerous and more 
peripheral in position. The nuclei are then found imbedded in a 
