24 Prof. F, Schmitz on the 
near the still-growing apex (fig. 29). On one of the large 
cells composing the wall of the tubular thallus-joints a four- 
celled branch is developed upon the cuter side, and this curves 
in a characteristic fashion and develops its apical cell into 
the carpogonium (figs. 30, 33). But over this carpogonial 
cell larger covering cells curve from both sides (more rarely 
from one side, fig. 31), which are segmented off from the two 
bordering cells of the thallus-wall, and bend over in such a 
manner that they are applied to the carpogonium by their 
extended margin, the conjugation-process (fig. 32). These 
two cells represent the auxiliary cells, of which, however, 
after the fertilization of the carpogonium, only a single one, as 
a rule, arrives at further development. 
4, As the clearest example of the structure of the female 
sexual organs in Spheerococcese the genus Nitophyllum may 
here be cited. In the species of this genus (e. g. N. venu- 
losum, Zan.) the formation of the sexual organs proceeds from 
a single cell of the originally always one-layered thallus. 
This separates off towards the under surface of the flat thallus 
‘several branch-cells, which further branch in various ways ; 
but superiorly it regularly forms two branch-cells, one of 
which develops a short sterile pluricellular branch, while the 
other, besides a terminal sometimes divided cell, develops a 
three- or four-celled small-celled branch, the terminal cell of 
which becomes the carpogonium. ‘This branch bends from 
its point of insertion in such a manner along the supporting 
cell, that its terminal cell is applied to the opposite end of 
the supporting cell, and then from the apex of this terminal 
cell the short trichogyne is extended outside through a fissure 
between the neighbouring cells. ‘This supporting-cell becomes 
the auxiliary cell. 
5. Among the Rhodymeniee, for example in Plocamium 
eoceineum, Lyngb., a short three-celled lateral branch, the 
terminal cell of which becomes the carpogonium, is formed 
supplementarily upon one of the larger cells within the locall 
enlarging small-celled external cortical layer (fig. 37). This 
short branch bends along the simultaneously enlarging sup- 
porting cell and then extends the trichogyne externally from 
the apex of the terminal cell through the overlying cellular 
tissue. ‘This mother-cell of the carpogonial branch, however, 
develops at its upper end a lateral diverticulum, a conjuga- 
tion-process, until it comes in contact with the carpogonial 
cell, and forms for its part the auxiliary cell (fig. 38). 
6. Finally, of the Gigartiner, Gigartina Teedii, Lmx., 
and Chondrus crispus, Stackh., likewise present, within the 
small-celled external cortical layer of the thallus, small secon- 
