MORPHOLOGY 
Sex organs. In the thallus body, often at the tips of special branches, 
there occur the conceplacles, which are chambers, each of which opens 
to the surface by a small porelike opening. Within these conceptacles 
the antheridia and oogonia are produced, the two organs appearing in 
the same conceptacle or in different ones (figs. 128, 129). The concep- 
tacles contain also numerous branching filaments (paraphyses) , which 
FIGS. 128, 129. Fucus: 128, an antheridial 
conceptacle; tap, an oogonial conceptacle. After 
THURET. 
130 
FIGS. 130, 131. Fucus: 
130, the oval antheridia borne 
on a branching paraphysis; 
131, the laterally biciliate 
perms. After THDRET. 
arise from the cells bounding them. The antheridia are borne as lateral 
branches of these paraphyses and are produced in great profusion (figs. 
130, 131). They are oval cells that produce numerous small laterally 
biciliate sperms. The oogonium is a large, globular, stalked cell and 
commonly produces eight eggs (oospheres) (figs. 132-136). There are 
related genera whose oogonia produce four or two eggs, and often only 
one; but in all of them eight nuclei appear. Such evidence suggests 
