A number of Bivalves have shells that gape even when closed.
The "Lutraria Lutraria" Mollusc is a deep burrower, maintaining contact with the surface by their massive non-retractible , united siphons . The foot is small and the mollusc is more or less sedentary.
This species burrows in mud and sand and lives on the extreme lower shore , it usually burrows 20-23cm into the sand or mud . It is commonly found down to 100m.
An Edible Clam - they seem be collected by the local Chinese Community.
Some of the shells are stained black from a sulphide layer deep in the mud , caused by a lack of oxygen.
Location: Saundersfoot Beach