Home > Invertebrates > Bivalves > Hyotissa numisma

Updated 8/20/2025

Family Gryphaeidae

INDO-PACIFIC / HAWAII

Hyotissa numisma

Portlock, Oahu, 35 feet

 

Makapu'u, Oahu, 20 feet

 


Sand Island, Oahu, 10 feet
   

COIN OYSTER

Common on the underside of ledges and rocks in shallow water.  Attains 2 inches.  Red Sea to Hawaii and the Tuamotus.  Ostrea thaanumi, Ostrea hanleyana and Parahyotissa numisma are synonyms.