1 82 Phillips . — The Development of the Cystocarp 
in appearance. Instead of readily taking up the stain, they 
are now the least stained in the whole section. No longer 
full of dense protoplasm, they are now vacuolated and 
granular. It is noteworthy, however, that the outline of the 
carpogonium is larger than before fertilization. The peri- 
central cell itself, at the earliest stage which I could obtain, 
had already divided as in Fig. 13, cutting off a large cell 
towards the apex of the branch. This derived cell is much 
larger and more conspicuous than the pericentral cell, which 
is greatly reduced in size by its formation. It is from this 
cell, undoubtedly, that the gonimoblast-filaments afterwards 
arise (Fig. 14) ; and it is highly probable that it is this cell, 
and not the pericentral cell, which constitutes the auxiliary 
cell and is fertilized by means of an ooblastema-tube from 
the carpogonium. Were the pericentral cell itself the 
auxiliary, it might be fairly argued that it would directly give 
rise to many gonimoblast-filaments, which it does not. An 
almost precisely similar case is that of Polysiphonia , in the 
Rhodomelaceae, where a cell derived from the pericentral cell 
is now considered to be the auxiliary, since from it, and not 
from the pericentral cell, the gonimoblast-filaments arise. 
Other Rhodomelaceae, like Chondria , occur, in which the 
pericentral cell seems to be the auxiliary. In all Ceramiaceae, 
it is a cell derived from the cell bearing the carpogonial 
branch ; and this I believe to be the case here. I did not 
succeed in finding any trace of the ooblastema-tube. It may 
be noticed, however, that the close contiguity of the carpo- 
gonium to the auxiliary cell is favourable for the process of 
fertilization. 
Fig. 14 represents an early stage in the development of 
gonimoblast-filaments from the auxiliary. The early cells of 
these filaments have an appearance which I have repeatedly 
observed. They are disc-like in shape, and seem to be 
separated by concave walls, fitting one into another like 
a series of cups. They probably arise in quick succession, 
pushing forward into the dense mucilage derived from the 
decadent sterile filaments. The pressure thus produced 
