Surf Barnacle

Barnacles are most unusual animals. They are arthropods, in the same major group as insects and spiders, and are most closely related to decapod crabs, prawns, lobsters and yabbies.

Unlike most of their relations, barnacles are usually fixed to a rocky surface. The larvae go through several distinct swimming stages as plankton, before settling into place onto a rock. The juveniles pick their place to settle because they can detect their adults by chemical means.