LIFE HISTORIES OF ALG^E 233 
the conceptacles is covered with more or less branched 
hairs (paraphyses) , and associated with these hairs are the 
organs that bear the sperms and eggs. In some species 
of Fucaceae both sperms and eggs are borne in the same 
conceptacle, and the plant is, accordingly, monoecious. 
This is the case with one of the species of Fucus (F. 
platycarpus}. In other species, such as those of Asco- 
phyllum and Fucus vesiculosus, sperms and eggs are borne 
in separate conceptacles, and even on separate plants, in 
which latter case the species are dioecious. 
213. Gametangia. The organs that bear either kind 
of gametes (sperms or eggs) are termed gametangia. The 
female gametangium differs in a very fundamental manner 
from the complex archegonium of the mosses and ferns, for 
it consists of only one cell, called the ob'gonium. The 
male gametangium, or spermagonium, is likewise unicel- 
lular, and the wall is composed of two layers, an inner and 
an outer layer. The spermagonia are in reality modified 
branches of the hairs that line the conceptacles. The 
oogonia are not attached to the hairs, but directly to the 
inner surface of the conceptacle by a short unicellular 
stalk. 
214. Gametes. The male gametes, or sperms, are 
formed by successive divisions of the protoplast of the 
unicellular spermagonium. Like those of the liverworts 
and mosses, they bear two long cilia, attached to the side. 
They also possess a pigment body, usually reddish in 
color. The oogonia of Ascophyllum commonly bear only 
four eggs, organized out of the protoplast of the oogonium, 
but in rare cases three or five. In some genera (e.g., 
Fucus} there are eight eggs. The nucleus of the oogonium 
cell usually divides into eight daughter-nuclei, but in 
