Sponges

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles.

The flatworms, known in scientific literature as Platyhelminthes or Plathelminthes are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals.

A sponge is a primitive sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibers or calcareous or glassy spicules. Sponges draw in a current of water to extract nutrients and oxygen.