Molluscs in culture Elder (1st century AD) in his "Natural History". The Gorgon of Greek mythology may have been inspired by the octopus or squid, the severed head of Medusa representing the animal, the beak as the protruding tongue and fangs, and its tentacles as the snakes. The six-headed sea monster of the "Odyssey", Scylla, may have had a similar origin. The Nordic legend of the kraken may also have derived from sightings of large cephalopods; the science fiction writer Jules Verne told a tale of a kraken-like monster in his 1870 novel "Twenty Thousand Leagues Under the Sea". Throughout the world, the
Twenty Thousand Leagues Under the Sea of underwater breathing apparatus designed by Benoit Rouquayrol and Auguste Denayrouze in 1865. They designed a diving set with a backpack spherical air tank that supplied air through the first known demand regulator. The diver still walked on the seabed and did not swim. This set was called an "aérophore" (Greek for "air-carrier"). Air pressure tanks made with the technology of the time could only hold 30 atmospheres, and the diver had to be surface supplied; the tank was for bailout. The durations of 6 to 8 hours on a tankful without external supply recorded for the Rouquayrol set in