Cells oval to oblong from the ventral side, anterior end asymmetrical, apex slightly to the left of the cell. Slightly dorso-ventrally flattened. Length 39 - 58 microns, width 25 - 45 microns, breadth (lateral) approximately 22 microns, length to width ratio 1.1 - 1.5. Proximal end of the cingulum originates 0.5 - 0.6 of the cell length from the apex, rising vertically to 0.2 - 0.3 of the cell length from the apex, then turning left and continuing initially at a slight upward angle on the ventral side. On the dorsal side, cingulum descends in a left turning spiral, ends not displaced. Cingulum initially narrow, widening to approximately 2 - 3 microns, becoming narrow where the ends meet. Sulcus narrow, curving to the right towards the posterior, where it indents the antapex. Apical groove continuing from where the cingulum changes direction, forming an anticlockwise loop around the apex. Longitudinal flagellum arising below the proximal end of the cingulum. Nucleus in the epicone, oval, 10 - 12 microns. One or two small reddish bodies occasionally present, probably food bodies. Numerous yellow-brown chloroplasts, 2 - 3 microns diameter, scattered throughout the cell. Cell surface uneven, covered in bumps approximately 1 microns diameter. Cells very fast swimming, changing to the non-motile form moments after becoming stationary. Non-motile cells round, covered in a hyaline layer, approximately 40 microns diameter, usually cingulum or sulcus not apparent.
