Fig. 11. TEM showing the chloride cell ultrastructure from the filamental epithelium of tilapia exposed to 75 g l^–1 salinity for 120 h. (A) Nucleus and perinuclear cytoplasm of an apoptotic chloride cell (CC). (B) Apical pit of multicellular complex that is partially covered by pavement cells (PC) projections; asterisks, cytoplasmic projections of accessory cells (AC). (C) Apical pit (A) that is completely separated from the ambient water by layer of PCs. (D) A multicellular complex without an apical pit; arrowheads indicate desmosomes joining CCs and ACs. (E) Chloride cell degrading by apoptosis. (E) Chloride cell at the final stage of apoptosis. Scale bars: 1 µm.