128 ARCHER, ON PALMOGL@A MACROCOCCA. 
vegetative growth. It might be assumed, indeed, in Cylin- 
drocystis Brébissonii, as cell-division is preceded by a division 
of the central corpuscles belonging to each half of the parent- 
cell, which now, therefore, contains four such, each equal in 
size to each of the two former, and as those nearer the ends 
seem to occupy the same relative position in respect of, and 
distance from, the ends, as the original ones did at first—in 
fact, apparently precisely the same situation—that the new 
space provided for the accommodation of the two inner cor- 
puscles is due to the addition at the centre of an extension of 
the cell-wall, which, after divisision, forms the nev, half-cells. 
But the central pale space is present throughout, and the 
division of the corpuscles is preceded by their elongation, the 
whole in the direction of the axis of the cell, as if this might 
be due to a gradual external extension all over of both cor- 
puscles and external wall. Indeed, in C. crassa (De Bary), 
which, as hereinbefore spoken of, occasionally presents its 
young recently divided cells elongating in a direction at right 
angles to the longitudinal axis of the mother-cell, there 
apparently takes place an elongation equally at both ends of 
the nascent cells. Moreover, in this genus the parent-cells 
seem to incorporate during conjugation, and do not split as if 
at a suture, the zygospore finally free within the cavity formed 
by the parent cells. But, again, the plants themselves seem 
to have considerable affinity to the genus Penium (Bréb.); but, 
as it seems to me, as Spirotznia, Mesotenium, and Cylindro- 
cystis, as I have above endeavoured to point out, are dis- 
tinguished from each other by their internal structure, so I 
believe is Penium distinguished from those by its internal 
structure. In Penium the granular contents form an axile 
mass, sending out all round in some species more or less 
irregularly divided, or in other species quite uninterrupted, 
plates to the cell-wall, which appear outwardly as more or 
less interrupted, or irregular, or tolerably uniform longitudinal 
bands, in end view radiate; but in these and other respects, 
as regards the species, characteristically disposed, and of 
course often containing starch-granules, or “ chlorophyll- 
vesicles.” This is briefly the character distinguishing this 
from the three other genera we have been considering. It is 
undoubtedly Dismidian. Although Spirotenia has always 
also been so considered, as already said, conjugation has not 
been seen in it. 
Such then is, so far as I can see, and as briefly as I can 
put it, the state of the case as regards the position of the 
Palmogloean species. Whether they be regarded as Desmi- 
dians, or as connecting that family with the Palmellacez, or 
