Sponges and cnidaria Sponges Key words Phylum Porifera cnidarian poriferan soft coral sponge Sponges (Phylum Porifera) c glass sponge ● Sponges are a group of very simple animals. They are also known as poriferans after their phylum Porifera. There are about 10,000 species, most of which are marine, though a few are freshwater. ● They range in size from a fraction of an inch (a few mm) to 6 feet (2 m). ● They have no nerves, muscles, or a calcareous sponge internal organs, and consist essentially of a body cavity connected to the exterior by pores. ● Sponges are filter feeders: flagellated collar cells line the body cavity and are used to create water currents that b horny sponge draw in oxygen and food particles. ● Four classes of sponge are recognized, based on structure and composition of Cnidarians the skeleton: Phylum Cnidaria class Calcare (a); class Demospongiae (b); class Hexactinellida (c); class Sclerospongiae (rare). Cnidarians (Phylum Cnidaria) ● Cnidarians are a group of simple d jellyfish animals that include sea anemones, jellyfish, hydras, and corals. ● There are about 9,400 species: most are marine, but a few live in freshwater. ● They are radially symmetrical with a mouth, simple sensory organs, and a nervous system. f soft coral ● They have one of two basic body patterns: polyp (hydroid) or medusa. ● They capture prey items using tentacles and nematocysts (stinging cells). ● There are four classes of cnidarians: class Hydrozoa (hydroids); class Scyphozoa (true jellyfish) (d); class Anthozoa (sea anemones, e, and corals, f); class Cubozoa (sea wasps and box jellyfish). e sea anemone Visual Information Ltd. © Diagram .