Marine Arthropods

Crustacea

Crustaceans are part of the phylum Arthropoda, including lobsters, shrimp, crabs, and barnacles. Crustaceans posses mandibles, cuticle exoskeleton high in calcium, two pairs of antennae, and 5 pairs of appendages on their head. Crustaceans grow by ecdysis or molding. In ecdysis, the old cuticle layers are broken down and the epidermis undergoes cell division and secretes enzymes that digest the old cuticle. Then, a new cuticle is formed inside of the old degenerating one. Crustaceans reproduced by specialized egg brooding and indirect development or metamorphosis is common in most crustaceans.

Merostomata

Members of this class are referred to as "living fossils", as they have survived for 455 million years. There are four living species today. Members posses a telson- a spiked terminal segment or tail. They are very important in pharmacology. Their blood has been used in the development of drugs, vaccines, and medical devices. They are found mostly in intertidal zones along the eastern coast of North America.