Fig. 10. Ultrastructure of the filament epithelium in carp 6 h (A–C) and 12 h (D–F) following recovery from hypoxia as viewed by scanning electron microscopy (SEM; A,D), and transmission electron microscopy (TEM; B,C,E,F). In A, which shows the epithelial surface, note the mucous cells (MCs), `shallow-basin' mitochondria-rich cell (MRCs; black-headed arrows) and `wavy-convex' MRCs with short microvilli (white-headed arrows). In B, note the shallow-basin MRC with branched microvilli protruding from the apical cavity. In C, note the wavy-convex MRC with short, wide, and slightly branched microvilli. In D, which shows the epithelial surface, note the abundant wavy-convex MRCs with branched microvilli (white arrows; McV) and MRCs with short microvilli (white-headed arrows). E and F show the apical area of wavy-convex MRCs with short and strait (E) and branched longer microvilli (F). PVC, pavement cell. Scale bars, (A,D) 10 µm; (B) 2 µm; (C,E,F) 1 µm.