What are molluscs?

Molluscs are animals without backbones. They include snails, octopuses, clams, oysters, etc. They can be found in the tropics as well as the Arctic and in sea or on land. Molluscs have soft, slimy and boneless bodies. The bodies have a covering made of big folds of flesh called mantles. In some like the oyster, the mantle is covered by a hard shell. Molluscs have a foot which is an extension of the mantle.