Structural characterization of Eutreptia pertyi (Euglenophyta). I. General description

Abstract The biflagellate cells of the photosynthetic marine euglenoid Eutreptia pertyi Pringsheim (Euglenophyta) have almost equal-length, heterodynamic flagella that emerge from the subapical opening of a tubular cana Vreservoir cavity. In addition to the 9 + 2 axonemal microtubules, both flagella contain filaments that form a basket-weave paraxial rod, but the arrangement of long and short non-tubular mastigonemes is different on each flagellum. A pyrenoid centre, surrounded by paramylon granules, occupies an anterio-median position in the cell, and 25–30 ribbon-shaped chloroplasts radiate from the periphery oft his complex. Certain cytoplasmic vesicles, here termed ‘mastigoneme vesicles’, are reported for the first time in the Euglenophyta, and may contain precursors or fully-formed mastigonemes; the fibrillar contentsare extruded byexocytosis into the lumen of the reservoir, where they are presumably assembled and deposited on to the flagellar surface.