Allen—Spermatogenesis and Apogamy in Ferns. 15 
this and the earlier stages that it has grown materially in mass. 
Shortly after this the cells round up, separating from each 
other. The intercellular spaces are filled with a slimy sub¬ 
stance that stains strongly with orange G. The nucleus moves 
to one side of the rounded cell so that the blepharoplast comes 
to lie near the plasma membrane. The nucleus increases in 
volume during this change in position and rounds out so that 
the blepharoplast and the nuclear membrane below it, run 
parallel to the plasma membrane. The meshes of the nuclear 
net increase in size and the small nucleoles disappear. The 
blepharoplast meanwhile continues to grow along the surface 
of the nucleus until it forms a broad band running half of the 
way around the nucleus and then out into the cytoplasm at one 
end, forming a curved, pointed beak at the anterior end. 
The fact that the cells in a sac are not oriented alike gives 
opportunity for studying them from all points of view. Fig¬ 
ures ten to twelve show median sections through the cell in three 
planes which intersect each other at right angles. Figures ten 
and eleven are longitudinal sections through the nucleus at right 
angles to each other and figure twelve is a cross section. The 
nucleus is slightly elongated, rounded at the posterior end and 
drawn out to a short conical beak along the inner surface of 
the blepharoplast, at the anterior end. The blepharoplast, as 
may be seen from the different sections (figures 10-12) forma 
a broad band along the outer convex side of the nucleus, curv¬ 
ing around the tip of the nuclear beak and projecting on into 
the cytoplasm at the anterior end. It is broadest in the mid¬ 
dle (figure 12) and narrower towards the ends (a and b figure 
11 ). 
The nucleus now pushes out at the posterior end forming a 
short conical projection (figure 13). The blepharoplast runs 
clear to its tip but does not extend beyond the nucleus as it 
does at the anterior end. The anterior end of the nucleus has 
meanwhile become longer and slenderer so that the entire nm 
cleus forms over three-fourths of a circle. 
At this stage a slow, gradual shrinking of the cytoplasm be¬ 
gins. Along the middle of the blepharoplast (figure 13) the 
plasma membrane has drawn in against it. This shrinkage is 
