FIG 6.

Feeding by V. algivore on Scenedesmus cells. (A) A Scenedesmus cell (arrow) is engulfed by a trophozoite. (B) Several Scenedesmus cells adhere to the surface of a plasmodium that has numerous vacuoles (arrow) in the cytoplasm. (C) One Scenedesmus cell (arrow) is ingested by an early-stage digestive cyst. (D) Digestive cysts in different stages; the small one (lower left) is in an early stage, and the engulfed cells (black arrow) are green and intact, while the large one is in a late stage and the ingested algal cells (white arrow) are near the center and are brownish. An empty cyst with some remnants of algal cells (arrowhead) has adhered to the large cyst. (E) Large floc with about 50 digestive cysts in different sizes and stages; the arrows point to some Scenedesmus cells that adhere to the floc. Scale bars = 5 μm (A to D) and 10 μm (E).