Fig. 4. (A–C) Light micrographs of gills from the mangrove killifish kept in water (A), in air for 1 week (B), and in water for 1 week after air exposure (all at 25°C). Note that the lamellae are present both in water and in air, but that an interlamellar cell mass fills up the space between the lamellae during air exposure. Scale bar, 40 µm (from Ong et al., 2007).