Family : Lepadidae
ID assistance to species level appreciated.
Lepas anatifera or Lepas pectinata maybe. Most of the mapped Encyclopaedia of Life records in the region are reduced to just Lepas sp.
Lepas pectinata is associated with pumice rafts in the region.
These barnacles have hitchiked a ride on this pumice stone which has washed up on this sheltered beach at Kingston on Norfolk Island. The bay/beach is known as Slaughter Bay. It’s name is not as ominous as it sounds as the word "slaughter" comes from an Old English word meaning "slow-moving water".
There are lots of these barnacles often attached to pumice stones which are plentiful on the beaches of Norfolk Island.