Crustaceans
Definition of Crustaceans Hierarchical Category as it relates to Animals, Amphibians
Crustaceans are a diverse group of arthropod animals including such species as crabs, lobsters, crayfish, shrimp, krill, barnacles, and woodlice. They are generally aquatic and breathe through gills. They have a hard exoskeleton that protects their body and provides support, which they must periodically shed in a process called molting as they grow. They are distinguished from other groups of animals and amphibians by their unique body structure, which typically includes two pairs of antennae and jaw-like mandibles.