Fig. 7. The distribution of digestive vacuoles in macrostomes in untreated microstomes (A) (control) and in cells treated with 0.3 µmol l^-1 (B), 3.0 µmol l^-1 (C) and 30.0 µmol l^-1 (D) nocodazole. Nocodazole largely prevented macrostomes from forming more than one digestive vacuole. In all experiments, the concentration of T. thermophila was 10⁵ cells ml^-1. The experiment was repeated three times, and 100 microstomal cells were counted in each experiment. Values are expressed as the mean + S.E.M.