124 A TEXT-BOOK OF BOTANY 
small, pore-like opening (Fig. 114). On the walls of these 
cavities o6dgonia and antheridia are produced. The odgo- 
nium is peculiar in that it usually produces eight eggs, 
which are discharged and float free in the water (Fig. 115, 
A and £). About these eggs the sperms swim in great 
numbers, often striking against them and setting them 
rotating (Fig. 115, F and H). Finally, a single sperm fuses 
with an egg and an odspore is formed, which later produces 
anew Fucus plant. 
This group of brown Alge, therefore, differs from the 
other one in producing no swimming spores, and in its 
dissimilar gametes (eggs and sperms). 
4. Rep Atam (Rhodophycec). 
74. General characters.—The red Alge are mostly 
marine forms, and receive their name from the fact that 
Tic. 116.—One of the red Alge. 
a red coloring matter completely masks the chlorophyll. 
As a consequence, the plants are various shades of red, 
