Approximately 30,000 species make up this phylum. Most are aquatic, the majority are marine but some are found in fresh water. Members of the phylum include lobsters, crabs, crayfish, shrimp, and barnacles. All have two pairs of antennae and a pair of compound eyes and two pair of maxillae on their heads, followed by a pair of appendages on each body segment.
King Crab (Brachyura)
King crabs are 6 in long and weigh 10 lbs. Crabs are decapods meaning they have 10 legs. Crabs are omnivores. They eat, mollusks, bacteria, worms and even other crustaceans, such as shrimp or barnacles. In times of desperation, they have been known to eat dead and decaying animals from the ocean floor. King crabs live up to 3 - 4 years.
Lobster (Nephropidae)
Lobsters are invertebrates that populate oceans all over the world. Lobsters are 2 ft long and weigh 1 pound. Lobsters live up to 50 years in the wild. The largest lobster ever caught was 4 ft long and weighed 44 lbs. Scientists think it was at least 100 years old.