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n. Plural form of crustacean.

noun-plural. One of the classes of the arthropods, including lobsters and crabs; -- so called from the crustlike shell with which they are covered.

A class of Arthropoda; one of the prime divisions of articulated animals with articulated legs, as distinguished from Insecta, Myriapoda, and Arachnida respectively.

n. class of mandibulate arthropods including: lobsters; crabs; shrimps; woodlice; barnacles; decapods; water fleas

"Closely allied to the crustacea is the sub-family of the _mollusca_, which includes the oyster, clams, and similar creatures; also the snails, cuttle-fish, slugs, nautilus, sea-squirts, etc., etc."

class   

mollusca    coleoptera    radiata    barnacle    limpet    helminth    invertebrate    abalone    mussel    mullets