262 BOTANICAL GAZETTE [APRIL 
cells that completely surround it and continue to undergo anti- 
clinal divisions without regularity, while the axial cell constantly 
enlarges, assuming a flattened barrel-shaped form. The origi- 
nally single cells of the younger filaments are thus converted 
into corticated segments indicated by slight constrictions in the 
older filaments ; the monstrously developed axial cells, which 
are filled with watery contents and contain few chloroplasts, 
forming a continuous series (fig. 74). The corticating cells 
which are irregularly polygonal (fg. 7) form, according to 
Schmitz, but a single layer even in the oldest filaments ; but 
although this seems to be invariably the case in the material 
from Cocoanut Grove, as shown in the figure last cited, it by no 
means applies to the Daytona form in which, although the origi- 
nal axial cells appear to remain undivided, periclinal divisions 
take place by which the corticating cells are separated into two 
well-defined layers (fig. z2), as is also indicated in Kuetzing’s 
Tabulae Phycologicae 7: pl. 88, jigs. 6 and f, which may be 
increased to three or even four in older axes like that shown in 
fig. 13, a portion of the axial cell being indicated at +. 
The filaments of Compsopogon are always more or less 
copiously branched, and although short secondary branches are 
sometimes developed from the corticating cells, the primary 
ones appear in all cases to be formed by the direct outgrowth of 
one of the undivided cells of the younger filaments. The alga 
when growing in still water may remain unattached, but is usually 
fixed to sticks, stones, or other plants, a short series of cells at 
the base remaining uncorticated and sending down rhizoidal out- 
growths which form an attachment analogous to that of Porphyra. 
An examination of the Cocoanut Grove material showed 
further that, although the cells of a majority of the plants gave 
no indication of any differentiation that might suggest a prepara- 
tion for some form of reproduction, in others the cells of the 
cortex as well as those of the younger uncorticated branches 
had evidently divided in a characteristic fashion; one, usually 
the smaller of the two resultant cells, being conspicuously differ- 
entiated by reason of its darker color and more dense contents; 
