The Last Plunge

volution had been kind to the air lion of Uranus. To the only animal inhabitant of a planet whose surface temperature is -180 degrees Centigrade, Evolution had granted the thickest fur coat of any animal known to man and a cold-blooded circulatory system. To the inhabitant of a planet whose atmosphere is mostly hydrogen and methane, Evolution had given a complicated respiratory apparatus that breathed in hydrogen and exhaled hydrogen sulfide.

To retain the balance of Uranian chemistry, Evolution had provided a brittle, yellow, rootless plant-life that inhaled hydrogen sulfide and exhaled hydrogen. To the inhabitant of a planet where most of the atmosphere was in a liquid state, Evolution had seen to it that the air lion was perfectly capable of living entirely in a liquid environment: a thick skin and heavy bone structure enabled the air lion to withstand the heavy pressures of the Uranian depths, gills made it possible for him to breathe liquids, and his powerful flippers made him the strongest swimmer in the solar system.