The term used to describe the creatures such as sea urchins and star fish?

The term used to describe creatures like sea urchins and starfish is "echinoderms." Echinoderms are marine animals characterized by their radial symmetry, a water vascular system, and a calcareous endoskeleton. They belong to the phylum Echinodermata, which also includes other species like sea cucumbers and sand dollars. These organisms are primarily found on the ocean floor and play important roles in marine ecosystems.