Echinoderms
Echinoderms always live in the ocean and are usually found in shallow areas. There are currently 7,000 species of echinoderms. All echinoderms have a mesodermal skeleton composed of calcareous plate. Some examples of echinoderms include sea stars, brittle stars, and sea urchins. The nervous system of echinoderms run from the mouth into each arm or along the body. They have tiny eyespots at the end of each arm which only detect light or dark. In addition to this the have tube feet which contain sensitive chemicals which allows them to find the source of smells
Sea star Brittle star Sea urchin