(356) 
of periclinal divisions at the micropylar end of the pyriform 
mass (fig. 92). 
Lagenarta 
Text-figure 5, A represents the form of the placenta at the 
time when the first indication of an archesporium is apparent. 
Periclinal divisions beneath the epidermis at the apex of each 
lobe (fg. 94) result in the separation of the primary tapetal 
and sporogenous cells. These periclinal divisions occur in 
several hypodermal cells and thus several series are found 
radiating from the spore-mother-cell (jg. 95). The division 
of the tapetal cells and those in the parietal series follows until 
columns of ten to twelve cells are formed and the sporogenous 
cell becomes deeply situated in the tissue of the nucellus. 
In the meantime the integuments have about reached the top 
of the nucellus. Before the germination of the megaspore 
takes place they converge above the nucellus and the ovule 
assumes the form which it maintains until after fertilization. 
Division of the spore-mother-cell occurs in the usual man- 
ner. The first division results in the formation of two equiv- 
alent cells, and each of these again divides (figs. 96, 97). In 
this case, as in some of the foregoing, it is the lowermost of 
the four cells thus formed which becomes functional. It en- 
larges rapidly after these divisions and soon enters upon the 
series of divisions which provide the eight nuclei of the 
embryo-sac. The division of the four nuclei to form eight 
occurs simultaneously, as shown by figure 98. Here the 
cytoplasm forms a peripheral layer and leaves the center open. 
Differentiation of the eight nuclei is soon apparent (jig. 99), 
and the synergids begin to appear with their usual structure. 
The antipodals are quite distinct and remain so up to the time 
of fertilization (fig. z00). In the latter stage, however, they 
are visibly shrunken and soon afterwards disappear. The 
egg-apparatus differs in no essential from those already 
described. 
An abundance of starch is now found in the neighborhood 
of the polar nuclei, which by this time have come into con- 
tact. In the preceding stage (fg. 99) no starch was apparent, 
