The 'auxosome'remains outside the f

The 'auxosome'
remains outside the frustule, grows and divides several times to form up to 30
flagellated infective offspring. The taxonomic position of Pirsonia is still
unknown. Electron microscope investigations on the ultrastructure, however,
suggest that it belongs to the Straminopiles (Schweikert and Schnepf, 1997).