(352) 
has developed a long funicle and the formation of integu- 
ments and nucellus is well under way (see text-figure 5, 7). 
The growth of the integuments now exceeds that of the nu- 
cellus and they soon enclose it. During this process the 
divisions of the spore-mother-cell take place. 
The manner of division of the spore-mother-cell recalls that 
of Zrichosanthes. Of the cells resulting from the first divi- 
sion the outer one degenerates, while the inner one proceeds 
to divide again (fg. 75). The figure just cited shows the 
conclusion of the second division and the deterioration of the 
upper of the two cells thus formed. The functional mega- 
spore immediately begins to enlarge preparatory to its first 
division, which is represented completed in figure 76. The 
succeeding divisions are quite regular and the embryo-sac is 
formed in the usual manner by three successive divisions of 
the megaspore (figs. 76-78). In this form the migration of the 
polar nuclei begins before any differentiation of other struc- 
tures is evident within the embryo-sac (fg. 78). At this time 
the embryo-sac is centrally situated in the nucellus, over which 
the integuments are slightly elevated. Conditions of the 
embryo-sac like those shown in figures 76, 77, and 79 may 
be found almost in the same section. In such cases, which 
are usual, the degree of the differentiation of the parts of the 
ovule is about the same in each, though they vary in size, 
the more advanced embryo-sac occupying the larger ovule. 
The difference in the degree of development of the em- 
bryo-sac and in the size of the ovule is probably associ- 
ated with some condition of nutrition, inasmuch as such 
differences are directly correlated with the position on the pla- 
centa. When the egg apparatus has become fully differenti- 
ated the embryo-sac occupies the center of the upper half of 
the nucellus, surrounded on all sides by several layers of 
sterile cells. The pyriform nucellus is surmounted by a 
slender beak which passes up through the micropyle. At 
this time the inner integument consists of two layers of cells, 
the outer one almost as thick as the nucellus. 
