Sponge

Any of the primitive multicellular aquatic animals that constitute the phylum Porifera. They number approximately 5,000 described species and inhabit all seas, where they occur attached to surfaces from the intertidal zone to depths of 8,500 metres (29,000 feet) or more. One family, the Spongillidae, is found in fresh water. Adult sponges lack a definite nervous system and do not show