274 The Ohio Journal of Science [Vol. XXI, No. 8, 



EXPLANATION OF PLATE. 



Figures A-F Oedogonium exocostatum nov. sp. 



A — Female filament with two oogonia and two oospores, one of the latter immature. 

 B — Elongated basal cell, showing habit of attachment. 

 C — Female filament, showing terminal oogonium with mature oospore. 

 D — Female filament with oogonium, oospore mature. 

 E — Male filament with antheridia containing sperms. 



F — Portion of vegetative filament showing variability in cell diameter and 

 elongation. Camera lucida drawings. 



