Griffiths.—On Glaucocystis Nostochinearum, Itzigsohn. 427 
straight edge along the line of fission. Sometimes the half-nucleus has one 
or more pointed processes (Figs. 8 and 9). These always lie on a line 
radiating from the karyosome towards the line of transverse fission. In 
some cases, numerous radiating lines of strain were found traversing the 
whole cytoplasm. Their centre of convergence lies at the karyosome, and 
they do not appear to cross the line of transverse fission of the cytoplasm 
(Fig. 8). The cytoplasm may show signs of division even before the 
division of the nucleus is initiated. On the other hand, it may be delayed 
until after. A distinct constriction appears in the equatorial plane. This 
is followed by a straight transverse fission which is always delayed until the 
nucleus has divided. After this, the cytoplasm rapidly rounds off, each half¬ 
nucleus becomes spherical, and two daughter cell-walls are formed (Fig. 10). 
In some cases the nucleus divides into four (Fig. 11), or even into eight 
(Figs. 12 and 14), and four or eight daughter-cells are formed simultaneously. 
In other cases two or four daughter-cells are formed, and a second nuclear 
division takes place (Fig. 15). Previous to the formation of daughter-cells, 
the mother-cell increases greatly in size. In the resting condition the cell 
measures about 30 [x by 18 [x. During division it may attain a size of 45 /x 
by 25 /*, that is, it about doubles in volume. The daughter-cells are there¬ 
fore about normal size. In this increase in size before division Glaucocystis 
differs altogether from Oocystis. Bohlin (’ 97 ) records that G. cingulata also 
varies greatly in size, the diameter varying from 12 to 56 \ ix, and the length 
from 16 to 56 /x. 
( e ) Division having taken place and the daughter-cells having been 
formed, the nucleus of each begins to undergo a series of degradations. 
The karyosome, that played so important a part in cell-division, breaks up. 
The stainable nuclear reticulum disappears, and the nuclear membrane can 
no longer be seen. The cytoplasm once more becomes full of deeply stain¬ 
ing granules, and the karyoplasmic area less definite and more feebly 
stainable. Ultimately the cell reaches the resting condition described in the 
first section. The nucleus is now represented by the vacuole-like karyo¬ 
plasmic area, and ceases to resemble the nucleus of higher plants. The 
chromoplast, which had broken up into numerous oval plastids during 
the stages of cell-division, reorganizes, and becomes once more a series 
of radiating recurved bands. 
Comparison with other Forms. 
The nucleus of the Myxophyceae is characterized by its irregular 
form, the absence of a nuclear membrane, the absence of a nucleolus, 
and by a tendency for cell-division to take place independently of nuclear 
division. Chromatin is present, and Kohl (’ 03 ) and Hegler have observed 
the formation of a chromatic figure. Wager (’ 01 ) also states that owing to 
the drawing out of the chromatin threads elongated cells often show stages 
F f 2 
