1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 427 
The nucleoli sometimes fragment into two cr three small globules, 
or decrease in size without fragmentation, finally vanishing during the 
late prophase. New nucleoli appear after the formation cf the 
daughter nuclei. No such close relation seems to exist between the 
linin thread and the nucleolus as to warrant a belief that in Poly- 
siphonia the nucleolar substance passes directly into the linin thread 
to form the chromosomes, as is reported in Nemalicn. 
No centrcsomes could be found during this process of mitcsis, 
although the kinoplasm surrounding the nuclear membrane becomes 
denser during later prophase and finally accumulates at the poles of 
the spindle at the time of the metaphase. The masses of kinoplasm 
present no radiations, yet it seems probable that they function as 
centers of dynamic activity during mitosis, persisting until the daughter 
nuclei are organized. | 
The mitoses within the germinating carpospore and tetraspore cor- 
respond in all essentials, except that it became at once apparent in 
the investigation that the nucleus of the carpospore contained about 
twice as many chromosomes as that of the tetraspore. Counts of the 
chromosomes made during the later prophase and metaphase of the 
mitosis made it clear that the nucleus of the carpospore contains 
about 40 chromosomes and that of the tetraspore 20. : 
SPERMATOGENESIS. 
The mitoses in the vegetative cell of male or antheridial plants will 
be described before those of spermatogenesis. During the prophase 
the chromatin granules increase in size and become grouped as a num- 
ber of short rod-shaped bodies upon the linin thread, without 
developing a regular and uniform chromatin spirem. The linin 
thread then segments into 20 chromosomes. 
Polysiphonia, as a rule, is dioecious; however, cystocarpic plants 
sometimes produce antheridia, a condition which will be described 
later with other abnormalities. The antheridia develop as lateral 
branches near the tips of the main filaments. Each branch consists 
of a central axis from which clusters of sperm mother-cells or sper- 
matocysts arise at the side on short stalk cells. 
The cytoplasm of the spermatocyst has a delicate granular struc- 
ture and contains a large vacuole, generally in the center of the cell. 
Its nucleus in the resting state is similar to that of the vegetative cell, 
