42 INTRODUCTION. 
kinoplasmic connecting fibers between the nuclei, and in the region of 
the cell-plate the cytoplasm seems undifferentiated. The plasma mem- 
branes, or cell-plates, which will separate the four spores, are laid 
down almost simultaneously. In the region where they are to appear 
the cytoplasm, as elsewhere, except near the nuclei, presents the same 
visible structure of alveole, or perhaps a mixture of alveole and a 
thread-like network. Rather large and small meshes are intermingled. 
po 
2 (a> 
cy Ct 
Fic. 16.—Cell-plate of Dictyota dichotoma and Stypocaulon. 
A, portion of cell-plate from tetraspore mother-cell of Dictyota, formed apparently by arrangement of 
alveolar lamellz into a continuous and even plane. 
B, same from apical cell of Stysocaulon,—(B, after Swingle.) 
The small-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 alveole becoming perceptibly thicker and arranging them- 
selves in such a way as to appear as an uneven or somewhat zigzag 
line in section (Fig. 16, A). In this cell-plate primordium the walls 
of both large and small meshes take part. At first certain of the alve- 
olar lamella are thinner than others, so that the cell-plate seems 
