are these what I think they are?

[darkreef]

Put your clam in a small dish with some sand . The snails burrow in the sand in the daytime . Throw out the sand come day time and scrub and remove them nighttime . Do this until there are no more !

(Also the snails may lay eggs on the sand next to the clam by accident )

Takes about a month to get rid of them but always keep checking