the Cystocarp in Rhodymen i ales. 351 
filaments is in a single cell arising from the base of the 
cavity, and derived from the same central cell from which 
emanate the filaments constituting the pericarp. This cell is 
the auxiliary cell, and there is no difficulty in understanding 
how conjugation may take place between the carpogonium 
lying against the base of the cavity, as I have described, and 
this auxiliary cell arising later in its immediate neighbourhood. 
Comparing now the cystocarp of Bonnemaisonia with those 
of Rhodomelaceae, several points of dissimilarity are apparent. 
First, while axial cells share in the formation of the cystocarp 
in both, these occur on the inner (ventral) side of the organ 
in Bonnemaisonia , and on the outer (dorsal) side in Rho- 
domelaceae. Secondly, the carpogonial branch is 2-celled 
in Bonnemaisonia, if the hypogynous cell which proliferates 
is included ; in Rhodomelaceae it is invariably 4-celled. 
Thirdly, while sterile filaments are found in the cystocarp 
both in Bonnemaisonia and Rhodomelaceae, in some cases, 
e. g. Dasya , among the latter even filling the young cystocarp 
as in Bonnemaiso?iia, yet in Bonnemaisonia these sterile fila- 
ments are formed exclusively from the hypogynous cell, and 
in Rhodomelaceae from two branches of the pericentral cell 
which gives rise to the carpogonial branch. Fourthly, no such 
paranematal filaments line the cavity in Bonnemaisonia , as 
invariably occur in Rhodomelaceae. 
On the other hand, the carpogonial branch is at first 
external as in Rhodomelaceae, and the apical pore is formed 
in much the same way as in that family. In both these 
respects, Bonnemaisonia contrasts strongly with Sphaero- 
coccaceae and Rhodymeniaceae, where the procarps are 
imbedded from the first, and the apical pore arises by 
dissolution. 
I look forward to obtaining opportunities of examining 
representatives of extra-British genera of Bonnemaisoniaceae : 
at present, however, I cannot but think, judging from Bonne- 
maisonia alone, that the isolation of the family by Schmitz is 
fully justified, and that the relationship to the other families 
of Rhodymeniales is not so close as has been represented. 
