Cuttlefish

Cuttlefish, or cuttles, are marine molluscs of the family Sepiidae. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control of buoyancy. They have large, W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from , with the largest species, the giant cuttlefish (Sepia apama), reaching in mantle length and more than in mass.

thumb|Cuttlebone of Sepia officinalis (left to right: ventral, dorsal, and lateral views). The cuttlebone is about 15cm in length. thumb| thumb|Tortoise with cuttlebone thumb|Fossil cuttlebone of the Pliocene species [[Sepia rugulosa]] thumb|Fossilised cuttlebone-like gladius (cephalopod)|gladius of [[Trachyteuthis]]