604 Williams . — The Gametophytes and 
cultures, especially if they are old, often have numbers of monads similar in 
shape and size, and even in the lateral attachment of the cilia, to phaeophy- 
cean zoogametes ; in some cases ectocarpoid reproductive bodies occur ; 
this makes it very difficult to be certain of the identity of laminarian 
antherozoids without having witnessed their liberation. 
Over a twelvemonth ago the writer was fortunate enough to be able 
to fill the gaps in the chain of proofs of the correctness of the theory 
explained above by observing the liberation of antherozoids, by securing 
fixed and stained preparations showing the fusion of the sexual nuclei of 
the fertilization, and, a little later, by actually witnessing the process of 
fertilization. In response to the urgent requests of botanical friends, 
a preliminary account of the phenomena is now published, leaving detailed 
descriptions and drawings to a further series of papers. 
The earlier stages in the development of the sexual generations are 
now sufficiently well known to make it needless to do more than give an 
outline of the course of events. Although the other British Laminariaceae 
have been studied, this account will deal only with Laminaria and Chorda. 
The pear-shaped zoospore, with its curved chromoplast and its pair 
of lateral cilia, after a short period of activity comes to rest, becomes 
spherical, and invests itself with a wall. A tube then grows out from one 
side of the spore, the chromoplast divides in two, and they, together with 
the greater portion of the cytoplasm, travel into the germination tube ; the 
nucleus, however, remains behind in the spore-case. The distal end of the 
tube swells until it becomes much bigger than the original spore ; at 
the same time the nucleus divides, and one of the two daughter nuclei 
migrates into the enlargement. A wall separates it and most of the 
original spore constituents from the basal bulb and germination tube, which 
are now empty save for the second nucleus, now rapidly degenerating, 
together with occasional traces of cytoplasm. In Laminaria the first 
division of the nucleus is accomplished as a rule in the spore-case, rarely 
in the tube. In Chorda the reverse is the rule. In Chorda also the tube 
is generally much longer than in Laminaria. In these two plants there 
is no perceptible difference between the early stages of the two kinds of 
gametophytes. 
In Laminaria vigorous cultures show differentiation of gametophytes 
in a week or less, and new sporophytes may appear in a fortnight. In slow 
cultures the time taken by the process may be very much longer. In 
Chorda no fertilization has yet been observed under three months, and very 
often the time occupied is six months or more. 
The young female gametophyte of Laminaria sometimes produces 
a new sporophyte without further division; in other cases a cell-chain is 
produced which may even show some amount of branching. These 
