Fig. 7. Hill plot of hemoglobin for tadpole shrimp reared under normoxic (19–21 kPa O₂; open circles), moderately hypoxic (10–13 kPa O₂; gray circles) or severe hypoxic (1–3 kPa O₂; black circles) conditions. Maximal slope for each rearing group represented by regression line. Cooperativities (n_H) for each group are given in Table 1. Values are means ± s.e.m. (N7). In some cases, the error bars were smaller than the symbols.