14 Wisconsin Academy of Sciences, Arts, and Letters. 
the shape of the nucleus hut the latter is often slightly flattened 
just beneath it. The different cells in a sac are not oriented 
alike—the blepharoplast being on one side in one cell—another 
in another. 
A slightly later stage is shown in figure four. Small nu¬ 
cleoles have formed in the nucleus. The exact time of the ap' 
pearance of the nucleole is not easily determined. These nuclei 
stain densely and the nucleoles are never conspicuous at any 
time. 
The blepharoplast here has become a denser rounded mass, 
smaller and more sharply stained than before. 
Figure five shows a still later stage in which there is a 
marked increase in the size of the cell and nucleus. The strands 
of the nuclear net are heavy and uniform in diameter as before. 
This nucleus showed no nucleoles although at the stage repre¬ 
sented they are generally present. Of the other nuclei in the 
same sac, some had two small nucleoles, others one, and a num¬ 
ber like the one drawn had none. There was a lack of uni¬ 
formity in the blepharoplasts in this sac. Several were still 
densely staining spheres. Others had elongated into a short, 
very narrow band, lying parallel to the surface of the nucleus 
but not in contact with it. 
A later stage is represented in figures six to nine. The cell 
has reached its mature size. The nucleus is still in the center 
of the cell. Some of the nuclei contain two nucleoles—others 
one. The meshes of the nuclear net are greatly increased in 
size, making the structure comparatively easy to examine. The 
cytoplasm has become vacuolated. 
The blepharoplast is here a band, tapering gradually to a 
point at one end, and coming more abruptly to a point at the 
other. This band lies across the nucleus, keeping parallel to 
the nuclear membrane and at a small distance from it, except 
at the narrower, thinner end which projects out into the cyto¬ 
plasm. This is probably to become the anterior end of the 
antherozoid. Figures six and nine show profile views and eight 
shows a surface view of the blepharoplast. Figure seven 
shows a section through the same nucleus shown in surface view 
in figure eight. It is plain on comparing the blepharoplasts of 
