Unidentified Clam From Liverpool N.S, Canada

[paul monfils]

Many of the ones I found also had such holes.  They are caused by moon snails of the family Naticidae, which feed largely on bivalve molluscs, and use their radula to rasp a hole in the shell of the prey.  Most likely predator in this case would be Polinices (Lunatia) heros.