Fig. 5. The effect of cytochalasin B (10 µg ml^-1) on phagocytosis in a macrostomal cell of Tetrahymena vorax. Both pictures are taken 30 min after the addition of T. thermophila to the medium. In the control cell (A), phagocytosis of three T. thermophila cells has occurred. In the cytochalasin-B-treated cell (B), the T. thermophila has been captured but no phagocytosis has taken place. DVs, digestive vacuoles. Scale bar, 20 µm.