A form of mollusc, without an external shell, somewhat like the octopus, but with two tentacles longer than the arms and with club-shaped ends and curious suckers. There are also narrow fins at the sides of the body ; and the mantle is supported on the inside by a thin plate, which is known as cuttle-fish bone.

These Are Used In Bird-Cages. They are not like true bone, but are formed of layers like shells, with a hard covering, and the birds peck small particles of lime from them.