MITOSIS IX CEDOGOXIUM 
147 
The change in form is no less noteworthy. As has alread}' been 
stated, the spherical resting nucleus assumes a fusiform shape 
early in the prophase (fig. 4) ; as the metaphase is appro;ached, this 
is frequently (but not alwaj^s) modified (fig. 7) by the prolonga- 
tion of the apices into acute tips. At this time the nucleus is 
quite plastic, and while S3^mmetrical figures are not uncommon, in 
many cases the form is more or less modified (figs. 8-12) chiefly 
by the pressure of adjacent pyrenoids. As is well known, the 
contour of the nucleus, in the higher plants, disappears in the 
prophase concurrently wuth the formation of the achromatic 
figure: in CEdogonium it persists, as will be noted more fully 
later, till late in the anaphase; it becomes still more elongated 
(fig. 15), but with little increase in volume. 
These changes in size and form are clearly indicated in the draw- 
ings of the three observers whom I have cited, but with little or 
no attention on their part. They appear to me to be noteworthy. 
The movement of the chromosomes toward the equator of the 
nucleus is characterized by great irregularity (figs. 8 and 9), 
some frequently lagging far behind the others. About this time 
the first traces of an achromatic figure can be clearly seen, in the 
form of a weakly developed spindle, which is entirely intranuclear. 
In many cases it is most strongly marked nearest the equator, 
giving the appearance of a ctntrifugal formation. The centro- 
some-like point shown in fig. 9 is the upturned end of an aberrant 
chromosome. 
As the chromosomes reach the equator they divide longitudin- 
ally (figs. 10 and 11) and the daughter chromosomes at once 
begin to separate. There is the same tendency to irregularity in 
their movements as in the approach of the chromosomes: the 
straggling metaphase of this form, as compared with that of most 
higher plants, having much the character of an attempt to fire 
a volley on the part of a company of ill-trained militia, as compared 
with the work of regular soldiers. 
Cleavage of all the chromosomes being finally accomplished, 
the groups of daughter chromosomes move with something of the 
same irregularity toward the poles of the nucleus (figs. 12 to 15). 
When they have become clearly separated, the achromatic figure 
