Very true. I've asked Paul about Philippine species but he's out of the office & won't reply until next week.
I put the item here on several forums in Europe and untill today nobody can give an answer. So I decided to give it meanwhile the name: "solecurtus kweetnie".
Last year whe have maded almost the same pictures in the Adriatic sea. I put them also on my website http://dive4fun.magix.net/ and go to the map Kroatië. From this species you can be for 100% sure that it is a bivalve. The creature of the Philipines you can't say it for 100% because you don't see clearly a shell.