Class: Crustacea (Crustaceans): crabs, shrimp, barnacles, sow bugs, etc.
Crustaceans possess:
- Mostly aquatic, free living parasites
- Two body regions – Cephalothorax and abdomen
- Pairs of antennae
- Varied number of legs (usually five)
- Respiration is done by skin or by gills
- Excretion is done by green glands
- Mostly unisexual.