gastrovascular cavity
Unlike the sponges which evolved prior to cnidarians, the cnidarians are made up of true tissues. The inside of a cnidarian is called the gastrovascular cavity , a large space that helps the organism digest and move nutrients around the body. The cnidarians also have nerve tissue organized into a net-like structure, known as a nerve-net, with connected nerve cells dispersed throughout the body. Cnidarians do not have true organs, however.