Purple snail Janthina janthina usually lives in temperate tropical seas, floating on the water surface for many years. Photo: Yan.

Because they cannot swim, the purple snail Janthina janthina can secrete many layers of mucous bubbles to help them hang upside down and float in the ocean following the ocean waves. Photo: Blogspot.

The female purple snail Janthina janthina lays her eggs right in the sponge raft until they develop into young larvae. Photo: Vietnamnetjsc.

When mature, the purple snail Janthina janthina will no longer be able to swim and must rely entirely on these saliva boats. Photo: Deepseanews.

The purple snail Janthina janthina is a typical pre-male hermaphrodite, when born male and then turns female when mature. Photo: Squarespace.