the Cystocarp in Rhodymeniales. 355 
The 3-celled carpogonial branches arise from a layer 
corresponding to that from which they arise in Plocamium . 
They seem to be distributed equally over the marginal 
surface of the pinnae ; and the trichogynes, when they reach 
the surface, which many apparently do not, do so at varying 
inclinations, though they are mostly directed forwards (PL 
XVII, Fig. 8). 
No auxiliary cell can be distinguished at the moment of 
fertilization any more than in Plocamium , and a considerable 
interval elapses before any gonimoblast-filaments can be 
detected. 
The first effect of fertilization is to induce a rapid growth 
in a group of cells lying over the carpogonial branch, and 
derived from the mother-cell of this branch. They become 
greatly enlarged, stain readily, and give rise to radial rows 
of cells which cause the papilla'r elevation which is the first 
outward sign of fertilization (PI. XVII, Figs. 9, t o). These might 
easily be mistaken for cells directly 'concerned with spore- 
formation. At this stage, the carpogonial branch may still 
be seen lying below apparently unaltered. A second effect 
of fertilization is the formation of a complex of small-celled 
filaments below and around the carpogonial branch. Before 
this has however attained any considerable development, there 
arises a tuft of gonimoblast-filaments between these inner and 
outer tissues marked in glycerine-material by the swollen 
cell-wall so characteristic of these sporogenous filaments. 
The basal cell of this tuft I regard as the auxiliary cell, and 
in position it is closely contiguous to the still traceable 
carpogonium. I could not decide, however, whether the cell 
which gives rise to the auxiliary cell is the mother-cell of the 
carpogonium, or the cell next above it. If, as I am inclined 
to believe, the auxiliary cell arises from the mother-cell itself, 
there is a close correspondence with the case of Plocamium. 
Schmitz and Hauptfleisch speak of the auxiliary cell merely 
as a ‘ closely contiguous cortical cell.’ As I have said, it is 
probably more than this, viz. a sister- cell to the carpogonial 
branch. Such however is the complex of placental ‘ rhizoids ’ 
