SAPOLEGNIA CE^ti. 



255 



some species the antheridia and oogonia are upon the same 

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



Fig. 171. 1, end of filament of Saprolrgnia with zoosport-s (swarm-spores) escap- 

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

 germinating : 5, a portion of a filament of Aehl> a, bearing sexual organs, x 120 : 6, 

 first stage in th . development of sexual organs of Acfilya ; 7. 8, 9. succeeding siages ; 

 10, sexual organs of 5, more enlarged, showing the anrheridia, jind 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 



