SAPOLEaNIACBM. 



355 



some species the antheridia and oogonia are upon the same 

 plants, and in such cases the fertilization takes place by the 



Pig. 171.— 1, end of filament of Saprolegnia, with zoospores (swarm-spores) escape 

 ing; 2, zoospores of the same at rest; 3, the same more enlarged; 4. tlie same, 

 germinating; 5, a portion of a filament of AcliLya^ bearing sexual organs, X 120 ; 6, 

 first stage in the development of sexual organs of Achlya ; 7j 8, 9, succeeding stages ; 

 10, sexnal organs of 5, more enlarged, showing the authendia, and the nearly ripe 

 oogonium, with its contained oospores. — Adapted from Hine. 



direct contact of the antheridium and the passage of its 

 contents into the oogonium by means of a tubular process 



