Fertilization of the Floridee. 95 
shoots forth laterally an uncinately curved carpogonial branch. 
Drawn without the camera, 
Fig. 30. The sixth joint-cell of fig. 29, with the adherent carpogonial 
branch, more highly magnified and drawn with the camera. 
The newly-formed trichogyne of the carpogonium strongly in- 
flated at its base on one side. 6, supporting cell of the carpo- 
gonial branch. x 800. 
Fig. 31. Young rudiment of a cystocarp seen from the outside of the 
thallus. The shaded cells represent the carpogonial branch : ¢, 
the ventral part of the carpogonium, the trichogyne of which 
was segmented off after fertilization and has perished; the 
dotted cell, b, the supporting cell of the carpogonial branch. a, 
the auxiliary cell, which bends towards the fertilized ovicell (c) 
with a broad conjugation-process ; m, one of the large cells of 
the wall of the¢hallus-joint, which has separated off the auxi- 
liary cel) (a) externally as a daughter-cell. This entire cell- 
group is covered by numerous small marginal cells, which the 
neighbouring cells have separated off, and which form the first 
rudiment of the future wall of the cystocarp. x 3800. 
Fig. 82. An auxiliary cell with a broad curved conjugation-process, seen 
from the side. x 800. 
Fig. 33. Carpogonial branch with fully-developed carpogonium, A sper- 
matium has conjugated with the apex of the trichogyne. x 
800. 
Fig. 34. Callithamnion gracillimum, Hary. 
(Material in spirit.) 
Procarpium. On one of the uppermost joint-cells of a completed branch 
of the thallus there stand in a whorl the sterile branch-cells (6), 
the two auxiliary cells (a), one of which has also segmented off 
a cell (d) on its outer side, and the three-celled carpogonial 
branch (ee c). x 800. 
Fig. 35. Pterothamnoon plumula, Nig. 
(Osmic acid and hzmatoxylin preparation.) 
Procarpium. The basal cell (6) of a frond-pinna bears upon one side the 
curved four-celled carpogonial branch, and on the other side the 
auxiliary cell (a). The latter has curved over towards the upper 
surface of the basal cell, and so comes in contact with the 
ventral part of the carpogonium, which has already separated 
from the trichogyne, as the fertilized ovicell, by means of a very 
short and dense closing-plate (p). x 800. 
Fig. 36. Polysiphonia atrorubescens, Grev. 
(Picric acid and hematoxylin preparation.) 
Young procarpium in median optical longitudinal section. On the joint- 
cell 6 of the central axis the unpaired marginal cell @ has seg- 
mented off a terminal offshoot, which already consists of two 
cells, and by the development of further transverse walls in the 
terminal cell will grow into the curved carpogonial branch of 
the fertilizably mature procarpium (fig. 28). x 800, 
