1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 425 
procarps are produced by the same plant. Sperms are occasionally 
developed in clusters at the nodal regions of older portions of fila- 
ments, more often on male plants, but sometimes they are formed 
hear the base of cystocarps. The sexual cells in these cases develop 
normally, the successive mitoses showing 20 chromosomes. 
Frequently certain of the stalk cells in an antheridium increase 
greatly in size (fig. 166) and divide again and again (fig. 167). The 
cytoplasmic structure and behavior of the cells resemble somewhat 
the auxiliary cells of the procarp, and it seems possible that there is 
present in such cases an organ of somewhat mixed character. 
The most noteworthy abnormalities, however, are those where 
cystocarpic or antheridial plants produce cells whose lineage is 
identical with that of the tetraspore mother cell (figs. 168—170g). The 
development of these cells was traced until they reached their full 
Size (figs. 1 70a-170g), yet the nuclei in almost all cases remained 
undivided (fig. r7od’), although the beginnings of cleavage furrows 
Were observed as shallow grooves (figs. 169-170g). These cleavage 
furrows never proceeded to the interior of the cell. Very rarely the 
nucleus appeared to enter a mitosis (figs. 171, I71@, 171@’) in old 
cells, but the number of chromosomes, small and round, were about 
20 in each daughter group, and there was no evidence of reduction 
phenomena; indeed, the cell was never divided. Whether this cell 
may escape from the parent plant and germinate as a monospore 
has not yet been determined. 
It seems probable that this peculiar behavior in Polysiphonia 
may offer an explanation of similar cases reported in the red algae 
where tetraspores are formed on sexual plants. They have been 
hoted in Chylocladia kaliformis (Lotsy 45), Spermothamnion Turnert 
and Ceramium rubrum (Davis 24), and Davis has also observed 
them on Callithamnion Baileyi. Such cases should be carefully 
investigated to determine whether true tetraspores are present or 
whether the structures are not really of the nature of monospores, as 
i Polysiphonia, and developed with a suppression of reduction 
Phenomena, In this case the apparent irregularity of the presence 
of asexual spores on a sexual plant would be explained; or it is of 
Course possible that in some cases the tetraspores are formed normally, 
but the sexual organs are developed apogamously. However, it 
