1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 427 
Some authors have gone still further and concluded that the 
chromosomes in certain forms are formed directly from the nucleolus. 
The studies of the algae and of lower unicellular organisms seem 
to support this conclusion. Thus TANcL (77), MEuNTIER (46), 
Mot (49), DECAGNY (24a), HENNEGUY (40), MitzKEWiTSCH (47), 
and VAN WIssELIncH (83, 84) on Spirogyra, GOLENKIN (34) on 
Sphaeroplea, and WoLFE (86) on Nemalion hold this view. There are 
naturally some differences in details among the authors mentioned 
above. For example, MOoLt states that the nucleolus of Spirogyra is 
found commonly exhibiting a skein structure, and that segments are 
formed by the transference of chromatin substance from the nucleolus 
into a nuclear plasm as small fragments arranged like beads in a neck- 
lace. MirzKkewrrscu points out that during mitosis the nucleolus 
increases in size and becomes differentiated into a number of deeply 
staining granular chromosomes. VAN WISSELINGH believes that in 
the same genus only two out of the eight chromosomes are derived 
from the nucleolus, and that in the reorganization of daughter nuclei 
both halves of these two chromosomes give rise to the new nucleoli. 
GOLENKIN describes the nucleolus of Sphaeroplea as breaking up into 
4 number of chromosomes which become arranged in a nuclear plate. 
Wo.rr on Nemalion states that the material of the nucleolus passes 
outward through radiating fibrillae (linin ?) into a number of chromatin 
- &ranules, which organize the chromosomes directly without the inter- 
vention of a spirem stage. : 
The most recent study on Spirogyra is by BERcHs(1r). He 
concludes that the nuclear network is not of chromatin nature, at least 
it contains in the resting state little chromatin and does not take part in 
the formation of chromosomes, whereas the nucleolus, at least at pro- 
Phase, contains all of the chromatin elements and does not disappear 
atany moment of mitosis. The nucleolus consists of two substances; 
from the first, 12 chromosomes become differentiated and arranged 
in a ring at the equatorial zone; the second substance remains in the 
orm of the original nucleolus. The second substance at anaphase 
‘plits into two groups of small rods (“‘batonnets”), forming segments 
Which pass to the poles with the chromosomes. These segments are 
6 in number, but are double longitudinally. The true chromosomes 
become attached in pairs at the equatorial ends of these segments. 
