Janthina janthina (Linnaeus, 1758)
Common throughout the Solitary Islands Marine Park. Distributed through seas worldwide. In Australia found in tropical and temperate waters.
A member of the Pleuston group of organisms that live on the surface of the ocean.
Almost spherical shell with a low, flat spire, they are often washed ashore in large numbers with on-shore winds. They all start life as a male released alive by the parent and later transforms into a female. The Violet Snail excretes mucous that hardens into a bubble raft which keeps the animal floating at the oceans surface. Feeds on surface cnidarians such as the Common Bluebottle, Physalia physalis, the By-the-wind Sailor, Velella velella, small jellyfish and crustaceans. Uses countershading camouflage strategy (shell darker above and lighter below) to avoid predators. Top photographs taken in aquarium. Grows to around 40 mm.
Graham J. Edgar. Australian Marine Life, 2nd Edition, 2008. Reed New Holland Publishers. p.291.