Fig. 6. O₂ consumption rates (ml O₂ kg^–1 h^–1) of various cephalopods plotted against swimming speed. Swimming speeds are expressed in (A) cm s^–1 and (B) mantle lengths s^–1. The 15 and 31 g Lolliguncula brevis in the figure correspond to the 5.3 and 7.5 cm dorsal mantle length (DML) squid, respectively, depicted in Fig. 3. These squid were selected as representative of this study because they were particularly cooperative and their O₂ consumption rates were close to the mean O₂ consumption rates for their respective size classes. Since Illex illecebrosus was considerably larger than L. brevis, its mass was adjusted to 30 g using the metabolic scaling equation: R=aM^b, where R is metabolic rate (ml O₂ kg^–1 h^–1), M is organism mass (kg), a is the mass coefficient and b is the mass exponent (–0.25) (O’Dor and Webber, 1986). For comparative purposes, O₂ consumption rates for I. illecebrosus were extrapolated to slightly lower speeds than those studied. The mass of each organism and the temperature of the water within the respirometers are included in parentheses. Sources of the data are listed in the figure.