in Dictyota dichotoma . 181 
connecting fibres between the nuclei nor any perceptible 
change whatever in the arrangement of the kinoplasm was 
to be seen. Only a few fibres or lines of force, indicated by 
the arrangement of the alveolae of the frothy plasma, extend 
from the nucleus of the apical cell to the seat of the cell-plate 
formation, and still fewer from the lower nucleus to the same 
place (1. c., Fig. 5 , XV). It is certain, he further remarks, 
that if these be real fibres, they must be extremely delicate 
and not numerous enough to lead one for a moment to 
suppose that the cell-plate is laid down by any such process 
as in the Metaphytes. And although the entire phenomenon 
is a process which does not depend immediately upon the 
activity of the kinoplasm, yet it is not impossible that it 
takes place under the control of the nucleus exerted through 
the kinoplasmic fibres which connected the latter with the 
former cell-plate. 
The development of the cell-plate in Dictyota resembles 
that in Stypocaulon . There is absolutely no visible trace of 
kinoplasmic connecting fibres between the nuclei, and in the 
region of the cell-plate the cytoplasm seems undifferentiated. 
The plasma-membranes or cell-plates which will separate 
the four spores are laid down nearly simultaneously. In the 
regions where they are to appear, the cytoplasm, as elsewhere, 
except near the nuclei, reveals the same visible structure of 
alveolae, or perhaps a mixture of alveolar and thread-like 
network. Rather large and very small meshes are inter¬ 
mingled. The smaller-meshed structure is apparently more 
granular than that with larger meshes. 
The first visible trace of a cell-plate is manifested by the 
transverse walls of the alveolae becoming perceptibly thicker 
and arranging themselves in such a way as to appear as an 
uneven or somewhat zigzag line in section (Fig. 16 ). In 
this cell-plate rudiment or Anlage , the walls of both large 
and small meshes take part. At first certain of the alveolar 
walls are thinner than others, so that the cell-plate seems 
interrupted at those places, but eventually and gradually 
it attains a uniform thickness. Very soon the cell-plate or 
