Dosima fascicularis

The buoy barnacle (Dosima fascicularis) is a species of goose barnacle known for its unique characteristic of hanging downwards from a buoyant appendage which drifts at the water surface and is carried along by ocean currents. It is regarded as "the most specialized pleustonic goose barnacle" as most other barnacle species are sessile filter feeders that remain fixed onto other firm surfaces. Formerly placed in the genus Lepas, the buoy barnacle is now generally placed in the genus Dosima, which is distinguished from Lepas by the form of the carina, and by the exceptional thinness and brittleness of its exoskeleton.