Sea Stars, Sea Urchins, and Their Relatives: Echinoderms (Invertebrates)

Echinoderms are a group of invertebrate animals that live in the sea. There are about 6,000 kinds of echinoderms, with the main kinds being sea stars, brittle stars, sea urchins, and sea cucumbers. Readers will learn about the life cycle of echinoderms, how they eat and defend themselves, and much more. They'll even get an up-close look at sand dollars and crown-of-thorns sea stars.