The Crustaceans (Subphylum Crustacea) include crabs, lobsters, shrimp, barnacles and many others. They live in the ocean and freshwater habitats, though many are able to live on land. Some crustaceans (barnacles) live attached to a solid object like a rock, pier, boat, or even a whale.
1) Crustaceans have a head, thorax, and abdomen.
2) On the head there are compound eyes, two pairs of antennae, one pair of mandibles for biting, and two pairs of mouthparts (maxillae) for pulling food into the mouth.
3) The thorax and abdomen have many segments, each with a pair of legs.
4) The front pair of legs are often, in many species, claws for grabbing prey.
5) The gills are also found on the thorax.
6) Crustaceans have a hard exoskeleton to protect them. It is shed (molted) and reformed several times, as they grow bigger.