Fig. 10. TEM showing the chloride cell ultrastructure from the filamental epithelium of tilapia exposed to 65 g l^–1 salinity for 120 h. (A) Deep apical pit (A) of a multicellular complex formed by interdigitated chloride cells and accessory cells (ACs); arrowheads, short tight junctions; asterisks, projections of ACs. (B) Perinuclear cytoplasm of a mature chloride cell, showing the extensively developed tubular reticulum. (C) Chloride cell at the early stage of apoptosis. (D) Apoptotic chloride cell with a cleft nucleus and highly condensed cytoplasm. Scale bars: 1 µm.