190 Phillips . — On the Development of the 
noticeable that whatever be the number of ‘ siphons ’ in 
Rhodomelaceae, whether four as in Polysiphonia violacea , or 
more than twenty as in Polysiphonia nigrescens , the number 
of pericentral cells cut off at the procarpial joint is always 
five. Dasya coccinea has about nine pericentral cells, besides 
a considerable additional cortex ; the central cell cuts off five 
pericentral cells. The carpogonial branch is four-celled as 
elsewhere, the terminal cell — the carpogonium — emerging 
at first as a minute papilla, and afterwards as a greatly 
elongated trichogyne. The trichogyne is unusually long, 
because it has to extend far enough to clear the tufts of 
filaments which terminate the fertile axes. Of the cells of the 
carpogonial branch, the lowest and the highest (the carpo- 
gonium) are in Dasya much larger than the two intermediate 
cells, and none of the four can be so sharply differentiated by 
staining as is the case in Rhodomela and Polysiphonia at the 
corresponding stage. 
I have looked carefully into the young procarps for those 
sterile derivatives of the pericentral cell which are invariably 
present in the other species, but I am not sure that both of 
these branches are present, or that even one is always present, 
at the stage when the carpogonial branch is already fully 
formed. Occasionally a single inferior cell may be detected 
(Fig. 1). Both branches may, however, be found a little 
later : the other pericentral cells have at this stage formed 
a complete investment for the fifth cell and its derivatives ; 
the procarp never assumes the ‘ bi-valve , appearance, observ- 
able in Polysiphonia and elsewhere. There is merely a slight 
hemispherical swelling on the upper side of the branch, from 
a pit in which the trichogyne emerges. 
Those procarps which advance beyond this stage are rela- 
tively few in number, and though the cystocarps appear 
numerous when mature and visible to the naked eye, the 
search for them in the intermediate condition just before they 
become thus visible is wearisome. When the procarp of this 
stage is examined, it will be found that an internal cavity 
is forming, owing to the growth of luxuriantly-branched 
