Preface to Class of Cephalopoda

Cephalopoda
Photo: Ralph Body 		Literal meaning: Head-footed

Common names: Cuttlefish, Nautilis, Octopus, Squid
Shell: The nautilus is the only member of this class with a " typical "shell.

  • The shell is divided into chambers connected by a tube (siphuncle).
  • The chambers are gas-filled allowing the animal to change its buoyancy.
  • The squid and cuttlefish have an internal stiffening rod which is called a pen in the squid and cuttlebone in the cuttlefish.
  • The octopus has neither a shell or an internal stiffening rod.

    Animal: All members of the class have tentacles, although the number and size varies among the subclasses.
  • The animals brain is large and well developed.
  • Large complex eyes are similar to those of vertebrates.
  • Tough bony mouth parts are commonly referred to as beaks.
  • A radula is usually present.

    Habitat: All members of this class are worldwide marine dwellers.

  • While the octopus prefer to hide among rocks, the other members of this class are free swimmers.

    Food: All are carnivores who move rapidly through the water or creep over the rocks in search of prey.

  • The octopus is a benthic hunter, which primarily feed on crab.
  • The cuttlefish also feed on the sea bed with a diet that include crabs and various crustaceans.
  • The squid are pelagic feeders spending their entire lives in mid waters, feeding on fish and other squid.

    Reference: Class - Cephalopoda