134 BOTANICAL GAZETTE [AUGUST 
the micropyle by growing in the direction of the nucellus. During 
this change in the nucellus the mother cell divides (fig. 11) into an 
upper larger and a lower smaller cell. The next stage seen (fig. 12) 
had a row of four megaspores, and the position of the upper two and 
again of the lower two would indicate that they were derived from 
these first two cells by a further division. Fig. 13 shows a disap- 
pearance of the two upper cells, indicated by the small nuclei and the 
12, 
the 
Fics. 11, 12, 13.—Fig. 11, two cells arising from megaspore mother cell; fig. 
chain of four megaspores. X930; fig. 13, four megaspores: three degenerating, 
fourth the embryo sac. X930 
narrowed effect of the cells themselves. The nucleus of the cell just 
over the basal one of the chain is being flattened and crushed by the 
development of its sister cell, which is to be the embryo sac: 
other sections there is a deeply stained cap over the micropylar end 
of the embryo sac, which is probably the remnant of the other megr 
spore or megaspores; at last this also disappears. From this tum 
on the embryo sac enlarges rapidly and becomes more vacuola 
(figs. 10, 14). . 
