Semiconical Covers in Valves of Navicula teneroides HUSTEDT

Abstract

Cells of Navicula teneroidesHUSTEDT were cultivated in Petri dishes for some months. Some valves were carrying semiconical membranous covers at on e or both poles of the valve interior. The shadow of the cover was vaguely seen by transmission electron microscope. The cover was clearly seen by scanning electron microscope. The existence of those covers may be peculier to this diatom at present. Some type-specimens of it mounted by HUSTEDT himself offer similar shadows in the light microscopic photographs.