situated on the upper border 
of the frond, or on particular 
small shoots, as the fructi- 
fication of the species, but 
LYNGBYE as early as 1819 
was in doubt whether this 
was really so. He suggested 
that they might possibly 
be some parasite, and 
since then these bodies, 
which were later named 
nemathecia, have been the 
subject of various inter- 
pretations and much dis- 
cussion. I have recently 
published a special paper 
on this question (1929), in 
which I have shown that 
the nemathecium does not 
belong to a particular para- 
site (Actinococcus), but that 
it is the nemathecium of the 
much reduced sporophyte 
ty 
NÅ L L 
QUI a y Pr 
7 “qj À 
Fig. 502. 
Phyllophora Brodiei. A, from a dredging south of Als in June, 8.5 m's depth, 
nemathecia in leaflets, terminal or marginal. B, from 12 metres’ depth off 
Ballen, Samso in August; with nemathecia and new sexual leaflets. 1.8 : 1. 
of Phyllophora Brodiæi growing on the gametophyte. I shall therefore refer the reader to 
Fig. 503. 
Phyllophora Brodiei. Lille Belt, 18—19 metres’ depth, June. 
of frond with undulated fertile margin. B, similar with young nematheeia. 
@ Hy pale 
the historical survey given 
in that paper and here 
give only a shortaccount 
of my own researches. 
The sex organs 
occur in particular sexual 
leaflets situated on the 
upper border of the flat 
frond (fig. 502) or in a 
marginal zone of the 
upper segments of the 
frond (fig. 503 A). Dar- 
BISHIRE, Who observed 
the sexual shoots, main- 
tained that the species 
is dioecious, and it may 
perhaps sometimes be so, but the two sexes usually occur in the same plant and 
often in the same organ. When the upper border of the frond is fertile, it is much 
