Octopuses, squids, cuttlefish and the chambered nautilus belong to class Cephalopoda, which means 'head foot'. Cephalopods are mollusks and therefore are related to clams, snails , tusk shells, and chitons. Some of these mollusks, like the bivalves, don't even have a head, or a brain. they have very powerful scences and. Most mollusks are protected by a shell and many of them are not very easy to move. The shell in cuttlefish, when present, is internal. The cuttlebone from cuttlefish is sold in many pet shops to supply calcium to birds. Squid also have a reduced internal shell called a pen (ink pen). Octopuses lack a shell all together.
Cephalopods are found in all of the world's oceans, from the warm water of the tropics to the near cold water at the poles. |
