1922] TAY LOR—PHAEOPHYCEAE 433 
cells being able to form eggs. Each cell swells, elongates, and the 
egg emerges through a terminal rupture at the end of the pro- 
tuberance. The opening of the oogonium forms a sheath around 
the base of the egg, which develops into the young sporophyte while 
attached to the gametophyte. Actual fusion of the gametes was 
not observed. 
Promptly following the papers on Laminaria, SAUVAGEAU pub- 
lished a similar study of Alaria esculenta, belonging to a differ- 
ent section of the same family. The gametophytes differed from 
the previous cases in several particulars. The ‘‘embryo spore,” 
or zoospore, which has passed into the resting stage, persists and 
may give rise to a second filament opposite the first. The game- 
tophytes are also larger, and the female has elongate cells, part of 
which only seem to produce eggs. The fertile cells form irregular 
lobes instead of remaining of the usual simple ovoid form, but only 
one egg is extruded from each cell. Sometimes the female thallus 
is reduced to a single cell, as is not infrequent in Laminaria, but 
is more often of from two to four cells, with the terminal one becom- 
ing fertile first, and then occasionally some of the others. 
In the same year that the Laminaria and Alaria studies of 
SAUVAGEAU were announced (1916), KyYLIN published a paper on 
an independent study of the life cycle of Laminaria digitata which 
confirmed the statements of SAUVAGEAU in all essential respects (8). 
- Kucxuck (7) and Pascuer (15) also later published confirmatory 
accounts of studies on Laminaria saccharina, The latter describes 
a most interesting departure, where he found that occasionally 
cells of the very young sporophyte, or even the undivided egg, 
might function as unilocular sporangia producing 2, 4, 8, or 16. 
zoospores. Finally, Ikart (4) described the gametophytes of 
Laminaria religiosa, which are like the two species already studied 
in most points, but at times have the antheridia in rows at the ends 
of the branches of the thallus, and shed the sperm by a terminal 
pore. 
In the year following his papers on Laminaria, SAUVAGEAU 
gave an account of the development of Dictyosiphon foeniculaceus, 
which demonstrated another unsuspected type of alternation. The 
evident plant of Dictyosiphon only produces unilocular sporangia. 
