
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.
Ref: 10830.1
Date: 18/09/2012
Location: Saundersfoot Beach