Nemalion multifidum , ^ 4 ^. 327 
Cell Structure. 
The cell-wall is lamellate, as is easily demonstrated by the use of 
swelling reagents. The interior of a vegetative cell is very largely taken up 
by the chromatophore, which rests towards the upper end and occupies 
about one-half to two-thirds of the cell space. At the lower end, especially 
in old cells, there is usually a large vacuolar area. Below the chromato- 
phore and between it and the vacuole lies the nucleus. It is very small, 
measuring usually about in diameter. Within the nuclear mem- 
brane lies a conspicuous nucleolus. The remaining space within the nucleus 
is occupied by a faintly staining, but unmistakable reticulum (PI. XXIII, 
Fig. 1). The nuclear cavity is never entirely empty of a reticular structure 
except in newly organized nuclei immediately following mitosis. At this 
stage, the small cavity is traversed only by a few radiating fibrillae which 
appear to suspend the nucleolus in the centre, the entire chromatin content 
being contained within this nucleolus. The details of mitosis in vegetative 
cells are very difficult to study, since the nuclei are small, and since, also, 
stages are not very often found, due to the fact that Nemalion is a slow- 
growing plant, only making eight to ten inches of growth in a season. The 
main details, however, have been made out satisfactorily, and it is certain 
that the chromosome number is about 8 as reported by Wolfe. Except 
for the absence of the nucleolus at metaphase, the details of nuclear 
behaviour (Figs. 1-3) are in entire correspondence with those seen in the 
cystocarp, where they are more easily studied. No detailed account, 
therefore, will be given at this time. 
The cells are joined by protoplasmic connexions. These stain an 
intense black with Heidenhain’s haematoxylin, so that they stand out very 
clearly. They appear as a pair of fused lens-shaped bodies, one to each 
cell, the edges of which are continuous with the inner surfaces of the cell- 
walls (P'igs. 23, 40, 43). Owing to their small size and deeply staining 
nature, it has been impossible to demonstrate protoplasmic connexions as 
clearly as has been done by Lewis ( 1909 ) for Griffithsia Bornetiana. That 
intimate connexions exist, however, can hardly be doubted. 
The Chromatophore. 
The most striking object in the cell is the chromatophore. It consists 
typically (Figs. 9-12) of a central region containing a pyrenoid-like body, 
surrounded by a dense enveloping layer, from which strands radiate out- 
ward to the periphery of the cell, where they flatten out to some extent 
against the plasma membrane. These strands may be long, like spokes of 
a wagon wheel, or short, like cogs, according as the central region of the 
chromatophore occupies a larger or smaller portion of the cell. In either 
case, they flatten out in the same way at the periphery. Usually they do 
