( 364 ) 
gids and odsphere can be clearly distinguished. Here the 
polar nuclei are smaller than they appear later and the anti- 
podals are in their prime. The antipodals will be seen to 
mature much earlier than the other cells of the embryo-sac and 
have erp eee as before the others have come to 
maturity (fg. 7 
The teed sac i Cucurbita Pepo presents a very striking 
appearance. The endosperm nucleus is possessed of an es- 
pecially prominent nucleolus and is surrounded by a cyto- 
plasm gorged with starch. The synergids being about two- 
thirds the length of the embryo-sac are somewhat compressed 
by the cytoplasm which surrounds their lower portion, which 
in each case consists of a very thin film enclosing a large 
vacuole. The nucleus in each case lies just above the vacuole 
and the upper two-fifths of the cell is hyaline and marked by 
exceedingly fine striations. In the embryo-sac of another 
garden variety of Cucurézta, the common crook-neck squash 
( fg. 137), the conditions are not the same, though in some 
points the comparison is hardly fair inasmuch as they are not 
quite in the same stage of development. The egg-apparatus 
presents much the same appearance as in the other form o 
Cucurbita, but antipodals are entirely absent. One feature 
is the entire absence of endosperm, though this may be due 
to the earlier state of development. The enormous size of 
the nucleoli in the polar nuclei is here one of the most salient 
features. 
Endosperm develops in Cucurdzta Pepo much as in other 
forms, in this family. Figures 734, 135 and 136 represent 
its appearance in various stages. The starch disappears 
early and the mass of cytoplasm becomes distributed periph- 
erally, and twenty-five or thirty nuclei may be formed be- 
fore the odspore has completed its first segmentation. The 
cytoplasm is more dense in the upper than in the lower por- 
tion and here also the nuclei are more numerous. The tissue 
of the nucellus falls before the growing endosperm. The 
endosperm soon becomes cellular in structure, the formation 
of walls beginning in the micropylar region (fig. 136). 
