the Cystocarp in Rhodymenia les. 353 
take up stain readily, they may be easily detected in sections 
prepared as I have described. The three cells making up 
the branch are curved sharply in a crescent on the outside 
of the cell from which they are derived ; so much so that 
two cells and the proximal portion of the carpogonial cell 
are contiguous to it. The trichogyne is usually somewhat 
inflated before it emerges at the surface. 
The first step which follows upon fertilization is the 
growth outwards, from the mother-cell of the carpogonial 
branch, of a cell which is in still closer juxtaposition with 
the carpogonium. This is doubtless the auxiliary cell, as 
from it later all the sporiferous filaments are derived. In 
the figures of Schmitz, to which allusion has already been 
made, it is the mother-cell itself which is described as the 
auxiliary cell. In the posthumous work (’97) prepared by 
Hauptfleisch, the Rhodymeniaceae are described, in contrast 
to the Gigartinaceae, as perfecting the auxiliary cell subse- 
quently to fertilization. In this case it arises only after 
fertilization. That this later-formed cell is the auxiliary cell 
is probable for this reason. From all analogy, a cell playing 
so important a part in reproduction is not likely after con- 
jugation to give rise to sterile filaments as well as to gonimo- 
blast-filaments. Now this mother-cell during the formation of 
carpospores gives rise to an abundant tissue constituting the 
inner layers of the hemispherical cystocarp. Davis indeed (’98 h) 
in his description of the cystocarp of Champia regards several 
cells as auxiliaries, some of which are figured as sharing in the 
formation of the pericarp. He, however, shows that these 
cells do not give rise to gonimoblast-filaments, and indeed, 
he only designates them auxiliary cells on the supposition 
that they are the cells which Hauptfleisch has called by that 
name. In the sense in which Schmitz and Hauptfleisch use 
the term, the only auxiliary cell in Champia is the one which 
gives rise to the glomerulus of spores. But to return to 
Plocamium . When the auxiliary cell has been cut off, the 
carpogonial branch may still be seen, the carpogonium being 
even larger than at the moment of fertilization of the trichogyne 
