OEDOGONIUM 



189 



antlieridium (Fig. 182, 

 B, a). The sperms, fre- 

 quently called anthero- 

 zoids by botanists, are 

 small, almost colorless 

 protoplasts, with a cir- 

 cle of cilia at one end 

 (Fig. 182, C) like the 

 zoospore. They are in 

 sharp contrast to the 

 eggs, being actively mo- 

 tile, ciliated, and with 

 very much reduced 

 chromatophore and food 

 contents. 



A cleft, or pore (Fig. 

 182, B, e), is formed in 

 the oogonium so that 

 the sperms may enter, 

 and one of them, fusing 

 with the egg, fertilizes 

 it. The egg after fertili- 

 zation develops a heavy 

 wall (Fig. 182, B, o) 

 and becomes an oospore 

 (meaning an egg spore). 

 The oospores, thus pro- 

 tected, can live through 

 drought or winter's cold 

 and so survive seasons 

 of the year impossible 

 for vegetative growth. 

 On the return of favor- 

 able conditions they 

 germinate, each oospore 



FIG. 182. (Edogonium nodulosum 



A, base of filament showing holdfast; B, filaments 

 with oogonia and antheridia; e, an egg ready 

 for fertilization, showing the cleft for the en- 

 trance of the sperm ; o, the thick-walled oospore ; 

 a, anthoridium, composed of four cells ; c, caps ; 

 C, sperms, showing crown of cilia ; D, zoospore ; 

 E, germination of the oospore, producing four 

 zoospores. C', I), E, after Juranyi 



