On THE PITHOPHORACEA. Do 
crassis et 216 w altis, his ¢:a 70 « crassis et 164 « altis; sporis terminalibus (non 
raro sessilibus) orculeformibus, sursum brevi-acuminatis apice rotundato, ¢:a 95 ju 
crassis et 232 «w altis.] 
Locality. Professor P. T. CLEVE has found this interesting species in the 
West-Indies, in the isle of S:t Thomas near Soldier-Bay on humid earth in the 
shade of bushes. 1) Oct. 1868. — Epiphytically on it grow two undescribed 
monoecious species of Ocdogonium, which it is my intention to describe in 
another place. 
General Description. I'ertile specimens. Caulojd part of the thallus. 
The ramification of this part is in P. Clevcana nob. somewhat more developed than 
in Pb. kewensis nob. Most specimens have, it is true, branches only of the 1I:st 
degree; but specimens with branches of the 2:d degree are far from being rare, 
and in a couple of specimens I have seen branches even of the 3:rd degree, but 
which have almost always consisted of only one sessile spore. The branches of the 
2:d degree are generally very short. Not seldom those branches consists (like those 
of the 5:rd degree) barely of one sessile spore; see pl. 4, fig. 13 ss. The principal 
filament is, when it ends in a spore, often very short, sometimes scarcely 2 m.m. 
long (pl. 2, fig. 13; pl. 4, fig. 16); the branches of the 1:st degree in such speci- 
mens are, it is true, longer, but not very much. Sometimes such little dwarf spe- 
cimens are quite devoid of branches, and remind one then in a very high degree 
of a gigafitice OUcdogonium with ellipsoidic oogonia. The branches are most fre- 
quently single, but not seldom those of the I:st degree are developed two and two 
from one cell and are then placed opposite, or almost so, to each other (pl. 2, fig. 
13; pl. 4, fig. 16; pl. 5, figs. 1 and 2). The normal branches in this species of 
Pithophora are placed, as in the others, a small space below the top of the sup- 
porting cell, which space is most frequently smaller than the diameter of the lowest 
branch cell, but can now and then be even longer (pl. 5, fig. 2). Cells without 
branches occur rather seldom, if you do not count the top cells?), the subsporal 
cells, and the cells belonging to the branches of the highest degree. The lowest 
one of the cells in the cauloid part of the thallus isenot seldom devoid of branches 
(pl. 4, fig. 15 and 16); sometimes, however, this cells carries more branches than 
the other cells, supporting besides the one or two ordinary terminal branches, 
an accessorial basal branch (pl. 5, fig. 1 and 6G). Accessorial branches, most 
frequently carrying helicoids, are now and then found even on other cells (pl. 5, 
fig, 1 ac). The comparatively frequent occurrence of helicoids is particularly re- 
markable in this species. Most specimens have one or more of these organs. These, 
generally consisting of the transformed top of a terminal cell, occur in numerous 
different shapes. Now they are unbranched (pl. 5, fig. 1 ’), now forked, now 
') Among the Cladophorew two species, viz. Cladophora Sagrewana Mount. (from Cuba) 
and Cl. tomentosa Sur. (from Japan), are known to cecur in similar localities. 
2) Top cells carrying branches are not, however, quite without instances. In small 
fertile: specimens you sometimes find the top cell of the principal filament, when it is a 
spore, carrying branches (pl. 2, fig. 13; pl. 4, fig. 16). 
