Fig. 2. A typical type-II cell (A-J), and those with a hairline-like apical opening (K-O) and with a wide apical opening (P-S) at 72 h of the seawater-to-freshwater transfer experiment. (A,C,E,G,K,P) X-Z optical sections. (B,D,F,H,I,J,L,M,N,O,Q,R,S) X-Y optical sections. n, nucleus; ^*, apical opening of type-II cell. Scale bar, 10 µm.