Beetles and other many-legged creatures belong to a huge “family” of animals we call arthropods . All arthropods have a jointed body, a shell, and three or more pairs of legs. Though arthropod means “jointed foot,” it is the legs that are jointed.
There are many kinds of arthropods in the sea. Shrimp, crabs, lobsters,
and barnacles are seagoing arthropods that have a special name. They are
called crustaceans. The name means “shelled ones.”
All crustaceans have a number of pairs of legs. Most have feelers, or
antennae for touching and feeling. Some can
also smell with their antennae.
All crustaceans breathe with gills. And most of them shed their shells
from time to time. For a while, the crustacean’s body is soft, and can
grow. Then, its outer skin becomes hard and is its new shell.
Some crustaceans are swimmers. Some only scuttle about on the bottom.
And some stick themselves head down onto a rock and never move
again—except to wiggle their legs!
common lobster