Fig. 2. Succession of infection stages among Cgranii cells infected by P.diadema (Experiment 2a).
Number of attached flagellates per valve: 0, no flagellates attached; I, 0-10 flagellates; II, 11-100
flagellates; III, up to 400 flagellates (attached flagellates were dividing); IV, empty frustules due to
infection.