Allantion tachyploon Sandon, 1924. Cells are 7-8.5x3.5 microns, cylindrical with rounded ends. A single trailing flagellum inserts sub-apically in a small depression. Cells glide swiftly with the whole of the flagellum in contact with the substrate, but with most of the posterior part of the cell raised above the surface. Gliding is sometimes interspersed by periods of a waggling movement. Cells may swim short distances, with rotation about the longitudinal axis, and the flagellum trailing behind
