Crustaceans

kru stA' shun, a class of arthropods characterized by having the body at least partially covered with a hard shell, including crabs, lobsters, shrimps, etc.

Subclass Branchiopoda
water fleas, fairy shrimp, tadpole shrimp, clam shrimp

Subclass Copepoda
copepods

Order Decapoda
crabs, lobsters, shrimps