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Article: Crustacean
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- Biology
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CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Crustacean
The Crustacea are a subphylum of the animal
phylum
Arthropoda. This is a large and diverse group with more than forty thousand species, including crabs, shrimp, lobsters, crayfish, barnacles, and many near-microscopic members of the zooplankton community. The subphylum is characterized especially by having mandibles and compound eyes and living in mostly aquatic habitats, although the "pillbugs" found under rocks and boards are also crustaceans, and many crabs spend much of their time on land.
The Crustacea are named for their hard, crusty
exoskeletons
, well known to anyone who has dined on lobster or crab. The hardness of the exoskeleton comes partly from
chitin
, but ...