THE ALGAE 



97 



ANTHERIDIUM 



ANTHEROZOIDS 



D 



RECEPTIVE 

 SPOT 





<3.;<?,,«i 







o C> c? O __ ::. 



o o o <;i O ^ '° ° y 



C> o O c> Q O O O ffjiC?- 



H 



J 



Fig. 78. — Vaucheria sessilis. A, Young antheridium. B, Antheridium and young oogonium. 

 C, Antheridium with septum and oogonium with developing beak. D and E, Protoplasm 

 returning from oogonium into filament. F, Liberation of antherozoids, oogonial beak 

 open, oogonium septate at base. G, Exudation of cytoplasm from oogonial beak. 

 H, Fertilization stage, antherozoids in extruded cytoplasm. J Oospore membrane 

 formed after fertilization. (After Couch.) 



