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1906] SIMONS—SARGASSUM FILIPENDULA 173 
that of the corresponding element in the conceptacle. Occasionally 
the tongue cell of the-cryptostoma may develop a prominent filament 
(fig. 20), which is clearly identical in structure with a typical paraph- 
ysis (fig. 21). The young conceptacle and cryptostoma are so alike 
that they can only be distinguished by their respective positions on 
fruiting branches or on young vegetative structures, until the appear- 
ance of sexual organs in the one and paraphyses in the other defines 
their mature characters. 
The development of the paraphysis is interesting for its regularity. 
A wall cell enlarges, pushing into the cavity of the cryptostoma, and 
then divides transversely (figs. 18, 20). The upper cell produces the 
paraphysis, whereas the lower functions in the development of the 
wall. The growth of the paraphysis results from the transverse divi- 
sions of the cell next the wall (figs. 21, 22), a method of growth termed 
trichothallic. ‘The development of a paraphysis in the cryptostoma of 
Sargassum is, therefore, characteristically basipetal, as BARTON (’91) 
found in Turbinaria. ; 
A somewhat advanced paraphysis is composed of three regions. 
That which adjoins the wall of the cryptostoma consists of the large 
turgescent meristematically active basal cell (fig. 22). The middle 
region is occupied by six or eight short cells which have so recently 
been formed that they have not had time to lengthen much. The 
upper region contains several greatly elongated cells. This region in 
a mature paraphysis is partly within the cryptostoma and partly 
without, for fully developed paraphyses extend far beyond the sur- 
face of the plant. 
A peculiar condition found in many cryptostomata deserves special 
attention. Structures frequently appear between the paraphyses 
which seem to bear no relation to them. These are papillae and 
stalked cells, the former like the papillae which precede male organs 
in a conceptacle and the latter like the male organs themselves. The 
stalked cells, although slender and probably always sterile, appear to 
be spermatocysts no longer functional. This surprising condition is 
of great interest and importance in relation to the homology and sig- 
nificance of the cryptostoma, a structure formerly believed to contain 
only paraphyses, but which appears also to have sexual organs or their 
degenerate representatives. That the cryptostoma and conceptacle 
