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1906] SIMONS—SARGASSUM FILIPENDULA 171 
cells are not aggressive they may be omitted from further consider- 
ation. Excluding this minor detail every portion of the conceptacle 
is the product of one initial cell. Cortical tissue adjacent to the ini- 
tial takes no part in its development. 
The behavior of the tongue cell is similar to that of the “initial cel]”’ 
in other forms as reported by Bower. It may show signs of degenera- 
tion (fig. 8), may remain inactive for some time (fig. rr), or may even 
divide to form a filament of two or three cells (figs. 9, 10). In-no case 
does it contribute to the walls of the conceptacle, but on the contrary 
after its divisions resembles a paraphysis. The tongue cell is very : 
conspicuous until sexual organs begin to develop, but shortly after 
their appearance it cannot be distinguished. The upper and lower cells 
which result from the transverse division of the initial cell (fig. 2) cor- 
respond in appearance and behavior with the “‘initial cell” and “basal 
cell” as described by Bower and others. It seems probable that 
Bower saw both the initial cell and the two-celled stage of the concep- 
tacle, but failing to observe the division in the initial cell, considered 
the initial and the upper cell of the two-celled stage identical. With 
this construction, degeneration of the upper or tongue cell was be- 
lieved to be degeneration of the initial cell itself, and the division of 
the lower cell of the two-celled stage, a product of the initial cell, was 
regarded merely as the division of an unrelated cortical cell. A 
conceptacle developed from cells which happen to be adjacent to a 
degenerating and unimportant cell would be a very different structure 
from a conceptacle developed from one active initial cell. | 
THE ORIGIN AND DEVELOPMENT OF THE CRYPTOSTOMA, 
The references embodied in the preceding treatment of the concep- 
tacle constitute the chief source of information bearing upon the cryp- 
tostoma. The structure which produces the sexual organs has com- 
monly and naturally been given first attention, but investigators who 
have studied both, generally agree that the conceptacle and cryp- 
tostoma are homologous. Different theories regarding the signifi- 
cance of the cryptostoma have been offered, but no safe generalization 
can be made until a more extended investigation of both structures 
has been made in a variety of forms. 
Miss Barton (’91) gave an account of the cryptostoma in Turbi- 
