Marine invertebrates

The term "marine invertebrates" is used to describe animals found in a marine environment which are invertebrates: lacking a notochord. In order to protect themselves, they may have evolved a shell or a hard exoskeleton, but this is not always the case.

As on land and in the air, invertebrates make up a huge portion of all life in the sea. Invertebrate sea life includes:

• Bryozoa, also known as moss animals or sea mats;


• Cnidaria, such as jellyfish, sea anemones and corals;


• Crustaceans, such a such as lobsters, crabs, shrimp, crayfish and barnacles;


• Ctenophora: sea worms including flatworms, ribbon worms, annelids, Sipuncula, Echiura, Chaetognatha, and the phoronids;


• Echinoderms, including starfish, brittle stars, sea urchins, sand dollars, sea cucumbers, and crinoids;


• Mollusca, including shellfish, squid, octopus;


• Sponges;


• Tunicates, also known as sea squirts.