Punalu'u, Oahu, 4 feet, 24mm

Okoe Bay, Hawaii, 30 feet

Kewalo Pipe, Oahu, 50 feet

Common on Porites coral at a permanent home scar.  Difficult to recognize due to heavy deposits of coralline algae.  Attains 1 inch.  Hawaii & the Indo-Pacific.  Formerly known as Coralliophila neritoidea.