Goose Barnacle
Lepas anserifera
Features: Rigid shell plates, stalk shorter than shell. Stalks of large specimens can reach 30 cm, but are typically much shorter. A similar species, Lepas anatifera, has a smooth shell and long stalk.
Notes: Open-sea species; attaches to floating logs, planks and other flotsam; usually only seen beach-washed. Both species common. Tropical Australia; worldwide.