THE FUNGI : ARCHIMYCETES AND PHYCOMYCETES 209 



: Zoosporangium 

 proliferating 



Fig. 200. — Saprolegnia ferax. Formation of terminal zoosporangia. 



Released zoospores 



Fig. 201. — Saprolegnia monoica. Mature zoosporangium and discharged zoospores. 



separated by a resting stage, is spoken of as diplanetism. The kidney-shaped 

 zoospores, after a further period of activity, settle down and germinate into 

 fresh hyphae. The second motile phase may be repeated more than once. 



Although the behaviour in the genus Saprolegnia shows the true picture 

 of diplanetism the conditions in allied genera are somewhat different, and 

 8 



