Acorn barnacle

Arthropoda – Cirripedia

Acorn barnacles have free-swimming larvae that attach themselves head-down onto hard surfaces, including rocks, jetties, boat hulls and even other marine animals and plants. As they grow, their external shell becomes a series of plates, and jointed legs develop into feathery appendages that trap plankton for food.

Did you know?

Barnacles are hermaphrodites – they have both male and female sexual organs. Barnacles can fertilise one another by using an extremely long penis or, if separated by long distances, they can fertilise themselves!