ALGAE 109 
Certain cells of the filament become very different from 
the ordinary cells, enlarging and becoming globular (Fig. 
99, A and B). In each one of these spherical cells there is 
Fic. 99.—Gdogonium: A, portion of filament showing vegetative cell with its 
nucleus (d),an odgonium (a) filled by a large egg packed with food, a second 
oégonium (c) containing an odéspore, as shown by heavy wall, and two antheridia 
(b), each containing two sperms; B, portion of filament showing antheridia (a), 
from which two sperms (b) have escaped, a vegetative cell with its nucleus, and 
an odgonium which a sperm has entered (c), and whose egg nucleus (d) may be 
seen; (, swimming spore; D and £, young filaments developing from swimming 
spores, 
