Eumetazoa have simple muscles and nerves that enable animals to move. Nerves conduct signals quickly and allow for fast responses and complex behavior. Muscles do the actual moving. While we wouldn’t call a jellyfish quick, they can—unlike sponges—move a little under their own power.

Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian.

What animals are in the class anthozoa?

• Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals.
• Anthozoa is included within the phylum Cnidaria, which also includes the jellyfish, box jellies and parasitic Myxozoa and Polypodiozoa.

Corals, sea anemones and jellyfish belong to a group of animals called cnidarians. They have a simple body consisting of a central gut cavity surrounded by tentacles. There are two basic cnidarian body shapes: a polyp form, which is attached to a surface; and an upside-down free-floating form called a medusa.

The phenomenon can be divided into four important stages: reproduction, egg development, settlement, and budding. Let’s dive deeper into each stage.

One of the most spectacular events to occur on the Great Barrier Reef is the annual synchronised spawning of corals. This mass reproduction only happens once a year. It involves colonies and species of coral polyps simultaneously releasing tiny egg and sperm bundles from their gut cavity into the water.

Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.