Fig. 3. A typical type-III cell at 0 h of the freshwater-to-seawater transfer experiment (A-J) and with noticeable apical NKCC staining at 72 h of the seawater-to-freshwater transfer experiment (K-U). (A,C,E,G,K,M,O,Q) X-Z optical sections. (B,D,F,H,I,J,L,N,P,R,S,T,U) X-Y optical sections. n, nucleus; ac, accessory cell; ^*, apical opening of type-III cell. Scale bar, 10 µm.