Class Crustacea


Members of the class Crustacea are structurally diverse. They generally have representations of the head, thorax and abdomen, however variation occurs in how the body segments are formed e.g. the head and thorax may be fused together to form a cephalothorax, some segments may be reduced and others modified. They have two pairs of antennae and at least 5 pairs of branched limbs. The limbs may be used in respiration, swimming, crawling and feeding. They may be highly modified as jaws, reproductive organs, various other structures or they may be simplified or lost. The majority of crustaceans are found in marine and freshwater habitats. The only widespread terrestrial crustaceans are sowbugs or pillbugs.