Fig. 4. Body lactate and glycogen concentrations in Pseudis paradoxus tadpoles and froglets after 3 h exposure to normoxic (open columns; mean P_O2=149 mmHg) and hypoxic water (filled columns; 60 mmHg) with free access to air at 25°C. Values represent the mean ± s.e.m. from N6 animals, staged according to Cais after Gosner (Cais, 1982; Gosner, 1960) and measured individually. The data are pooled into groups of stages representing distinct developmental steps of the larval period. `a', significantly different (P 0.05) compared to stages 33–37 in the normoxia series; `b', compared to values for normoxia in the same group of stages; and `c', from stages 33–37 in the hypoxia series.