368 BOTANICAL GAZETTE [MAY 
Fic. 3.—Mature cells somewhat irregular because : a 
Fic. 4.—Different stages in the formation of filam 
Fic. 5.—Optical section showing vacuole (a) and cla (e). 
Fic. 6.—Mature filaments. 
Fics. 7, 8.—Filaments showing cells reproducing before dissociation. 
Aeronema ee nov. gen. 
Fics. 9-12.—Young filam 
Fics. 13, 14.—Older ees taken from a culture in 0.3 per cent Knop’s 
solution 
IG. 15.—Unicellular condition taken from an old culture in 0.3 per cent 
age s solution. 
G. 16.—Parenchymatous mass taken from an old culture in 0.05 per 
cent te s solution. 
Fic. 17.—Different stages in the formation of zoospores from the uni- 
cellular condition. 
Fic. 18.—Zoospores 
Fic. 19.—Germinating zoospores. 
