38 Wisconsin Academy of Sciences, Arts, and Letters. 
Cycas and Marchantia that the centrosome forms within the 
nucleus before the last division and then moves out through the 
nuclear membrane into the cytoplasm. Yamanonchi, though 
non-committal, considers this as a possibility in Nephrodium 
molle. Thom, whose work like my own was largely on Adian- 
tum, inclines to the belief that the nucleus of the antherozoid 
mother cell in moving to the side of the cell leaves one of its 
large nucleoles behind in the center of the cell and that this 
nucleole later becomes attached to the anterior end of the nu¬ 
cleus and becomes the blepharoplast. 
My preparations do not support either of these views. The 
figure that Thom gives (fig. 27) of the stage before the ap¬ 
pearance of the blepharoplast corresponds very closely to what 
I find in the sixteen-celled stage of the sac. I do not find 
large nucleoles and finely divided chromatin in nuclei after the 
last division. I find the blepharoplast present in the cytoplasm 
before the appearance of the antherid nucleole and continuously 
present in all succeeding stages. The blepharoplast certainly 
does not originate as a nucleole. 
Although the nucleole as such does not move out into the 
cytoplasm and become the blepharoplast, the possibility is of 
course not excluded that the material for the growth of the 
blepharoplast is derived from the nucleus. Strashurger holds 
this view. In the swarm-spores of Oedogonium , Strashurger 
finds that the hyaline disk about which the cilia grow, forms 
only when the nucleus is in contact with it. In antherozoids, 
too, the nucleus and blepharoplast are closely associated. These 
facts suggest to Strashurger that the source of material for the 
origin and growth of the blepharoplast lies within the nucleus 
and may perhaps be found in the nucleoles. 
This, of course, cannot he regarded as proved, still, the con¬ 
tact of two organs while one increases in size suggests that the 
one is furnishing material for the growth of the other. The 
blepharoplast which is seen in the young antherid cell certainly 
increases in volume many fold during its development. Still, 
the nucleoles found in the nucleus of the growing mother cell 
are far too small to supply sufficient material for all this growth. 
