(silly-off-rees), a pedinellid stramenopile, with a single flagellum. The cell may exist as a non-swimming form with radiating arms, and with the flagellum inactive or beating in a languid figure of 8 motion. The arms can be resorbed, and the cell can then swim with the flagellum pulling the cell forward. This is the heliozoon form, with a nucleus in the centre of the cell. Phase contrast.