116 ARCHER, ON PALMOGL@A MACROCOCCA. 
new septum. Now, whichever of these cases holds good, the 
elongation of each new cell seems to take place in the 
direction of a line connecting the two new central corpuscles, 
which always thus lie in the direction of the longitudinal 
axis of every cell when about to divide, which always, as 
before stated, takes place transversely, or in the direction of 
the narrow diameter. Thus, in the former case, the re- 
petition of the process of cell-division does not alter the 
relative positions of the (so to speak) north and south poles 
of the generations of cells, whilst in the latter case each 
alternate repetition of cell-division changes the longitudinal 
axis of each generation from running north and south to east 
and west, and vice versd, in the following generation ; that is 
to say, each repetition of the process presents a division of 
the cell-generations according to two directions alternating 
with each other at right angles. I do not imagine that these 
two modes of behaviour possess any specific importance ; 
further observation may determine if they have. The latter 
mode seems, so far as my experience goes, to be the rarer; 
whilst I fancy also the plants presenting it seem to be larger 
usually than those which exhibit the former plan. The en- 
dochrome in this plant is very dense and opaque, rendering it 
a matter of great difficulty to discern a nucleus, or the 
arrangements of the contents. It is perfectly distinct as a 
Species, and constant, and the remarkable peculiarities of 
which I have endeavoured to convey an idea strikingly 
distinguish it from any of its allies. The plant is by no 
means uncommon kere, though Kiitzing gives but one locality 
—the Black Forest. De Bary does not say whether it is 
common or rare, but I should argue from the context that it 
is as common with him as here. So much, in passing, for the 
genus Cylindrocystis. 
I shall now advert to the last genus, Mesotzenium (Nag.). 
Plate VI, figs. 1 to 31. In this genus the structure of the 
cell-contents is different from any of the foregoing. Here 
there runs, either directly through the longitudinal axis of a 
cell or sometimes slightly excentrically, a more or less 
compressed, sharply defined, dense ‘‘chlorophyll-plate” (often, 
however, difficult to be detected, I believe, owing only to 
being hidden by the remainder of the contents), whose 
margin either touches the cell-wall or leaves a more or less 
wide intervening space. When the remaining contents are 
not too dense and abundant to permit its being readily 
perceived, this chlorophyll-plate, when its edge is towards the 
observer, appears either, in some species, like a narrow, 
vertical, axile, green band, swollen at the middle at each side, 
