Cafeteria roenbergensis Fenchel and Patterson, 1988. Cells are D-shaped, 2 to 5 microns long, and laterally compressed. There is a shallow groove on the left side of the cell. Two flagella of similar length emerge subapically and are slightly longer than the cell. The anterior (= feeding = hairy - the hairs are not visible by light microscopy) flagellum is directed perpendicular to the ventral face of the cell of attached cells. The posterior flagellum is reflexed, passing over one face of the cell and then attaching to the substrate by the tip. In swimming cells, the anterior flagellum is directed forwards and beats with a sine-wave, and the posterior flagellum is directed backwards and trails. Usually the cells move quickly following a spiral path, but sometimes they move slowly. Bacteria may be ingested near the anterior part or posterior part of the ventral groove.