€ r Fr 
24 Nr. 2. L. KoLDERuP ROSENVINGE: 
multiple origin of the sporogenous cell-rows the nema- 
thecium of Ahnfeltia differs essentially from that of Phyllo- 
phora Brodiei, where the whole complex of nemathecial 
filaments normally derives from one auxiliary cell.” 
Further, as mentioned above, the nemathecial filaments 
of Ahnfeltia differ by not producing tetrasporangia but 
monosporangia which are not seriate but develop only in 
the end-cells. The question of the morphological signific- 
ance of the monosporangia is no easy matter to solve. The 
fact that they occur in nemathecia suggests that they might 
be interpreted as originating from tetrasporangia which 
have failed to be divided owing to the wanting reduc- 
tion division of the nuclei. Such a division at any rate 
does not take place in the monosporangia and it seems 
too to be precluded at any earlier moment; its occurrence 
seems further to be improbable as a fertilisation or an 
-Ug'apomictic process has not been ascertained, 
The secondary nemathecial filaments may also be inter- 
preted as gonimoblast cell-rows arising by apogamy from 
the generative cells, and the whole complex of secondary 
nemathecial filaments would then be a compound cysto- 
carpium, the gonimoblast filaments issuing from numerous 
generative cells. According to this view the monospores 
are to be regarded as carpospores: the nemathecia repre- 
sent the carposporophytic phase and the tetrasporophytic 
phase is wanting. Such a compound cystocarp is not other- 
wise known among Florideæ. 
The fact that the spores are terminal on sterile cell- 
! It seems, however, that a large Actinococeus nemathecium may 
sometimes arise by fusion of primordia of nemathecia issuing from two 
or perhaps more contiguous auxiliary cells (comp. K. ROSENVINGE 1929 
p. 22 plate figs: V—VIII). 
