ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
83 
clusters. The author considers Sauvageau’s suggestion of dividing off 
Laminariaceae to form an entirely separate group is justified, but as yet 
somewhat premature. As regards the germination of the zoospores of 
L. saccharina the extending germ-tube forms a globular swelling at its 
end, which then proceeds to divide up, whereby the spore and the 
adjoining portion of the tube are left empty. Apparently a few-celled 
protonema is then formed. E. S. Gf. 
Gfametophytes and Fertilization in Laminaria and Chorda. 
(Preliminary Account). — J. Lloyd Williams ( Annals of Botany , 
1921, 35, pp. 603-7). In the study of artificial cultures of germinat- 
ing spores of Laminariaceae the presence of a much smaller brown alga 
is always observed ; the terminal cells of its branches are often found 
to be empty ; and the question arose whether these could be the 
antheridia of the male gametophyte. In the mixture of organisms of 
the culture it is exceedingly difficult to prove such a point ; yet the 
author had the great luck actually to observe the liberation of the 
antherozoids, and to secure stained preparations showing the fusion of 
the sexual nuclei, and even to witness the process of fertilization. He 
gives a preliminary outline of the course of events in the development 
of the gametophytes and the process of fertilization of Chorda and 
Laminaria. The male gametophyte is much smaller than the female, 
and divides up into much smaller and more numerous cells. The apical 
cell becomes paler, and, after the modification of its cell-wall, bursts 
and liberates the single antherozoid ; gradually the other cells escape 
in like fashion. The formation of the oogonium and the thickening 
and subsequent rupture of the oogonial wall are described ; the solitary 
egg was observed to be fertilized after emergence. Preparations were 
obtained showing the gametic nuclei in various stages of fusion. The 
new sporophyte, which often remains attached to the empty oogonium, 
grows rapidly, is positively heliotropic, and by vegetative structure and 
hv staining (with polychrome methylene-blue) can be readily distin- 
guished from the gametophytes. The first rhizoid appears early. The 
gametophytes of Chorda are much larger and further developed, but 
take a much longer time to mature ; and the critical stages are much 
more difficult to observe. Also the mode of emergence of the egg is 
very different from that of Laminaria ; the oogonial wall thickens but 
little, its outer layer bursts, and the contents, instead of emerging 
completely, grow out still enclosed in the extensible inner oogonial 
wall, the basal part thus remaining within the oogonial cavity. The 
young sporophyte accordingly is more securely anchored to the gameto- 
phyte than is the case in Laminaria ; further it grows more rapidly 
than in that genus. There is in Laminariaceae a pronounced alternation 
of generations, with a great reduction in the gametophytes. “ The cases 
in Laminaria where the gametophyte consists of a single cell separated 
from the zoospore by a single nuclear division make it easy to adopt 
the suggestion that the so-called oogonia and antheridia in the Fucaceae 
are sporangia. The systematic position of the group has to be changed : 
and we now get rid of the anomaly of regarding the alga which shows 
the highest advance in histological differentiation as a member of the 
g 2 
