What is the seashell?

The seashell is every shell-bearing mollusc. Molluscs are invertabrae animals with a unified symmetrical body that is made up of a head, a leg, internal stomach and covering. Molluscs are descendents of primitive worm-like creatures which moved slowly through mud on the seabed millions of years ago. As dissolved masses began to seep salts and chemicals into the oceans, the first molluscs assimilated them and gradually used them to build sturdy shelters.

Today, molluscs are not only found in the ocean but also in sweet water on land. Sea molluscs usually use gills to breathe whereas land molluscs have lungs. Their main feature is the lack of an internal skeleton. The shell serves as an outer-skeleton protecting the soft body from the outside world. The shell is in fact only loosely joined and does not provide support or rigidity to the animal. In fact, some molluscs such as the octopus or the squid do not use shells at all.