Clams live in mud or sand and are housed in a bivalve shell with 2 openings. One pumps in, bringing food, water and oxygen. The other pumps out water and wastes. Clams do not have a head, radula (the snail tongue) or tentacles.

Snails reproduce with eggs. The eggs are retained in the shell of the clam until they hatch and are released as larva. Some clams can release as many as 3 million larva. In some species the larva can be parasitic.