View source for Crustacea

{{Definition|title=Crustacea, crustaceans
|definition=A group of freshwater and saltwater invertebrates with jointed legs and a hard shell of chitin.  }}


==Notes==
Subphylum of arthropods, considered as a class in older classifications.
They are mainly aquatic, gill-breathing animals, such as crabs, lobsters and shrimps. The body is divided into a head bearing five pairs of appendages (two pairs of pre-oral sensory feelers and three pairs of post-oral feeding appendages) and a trunk and abdomen bearing a variable number of often biramous appendages wich serve as walking legs and gills. Crustacea often have a hard carapace of shell.<ref name="Hendersons"> Lawrence, E. (2005). ''Henderson’s dictionary of biology.'' Pearson Education Limited, 13th ed., Harlow. 748 p. </ref>


==References==
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