What animals live in a shell the water?

* Mollusks: Mollusks are a large group of animals that includes snails, clams, oysters, and octopuses. All mollusks have a soft body that is protected by a hard shell. Many mollusks live in the water, although some, like the land snail, live on land.

* Arthropods: Arthropods are another large group of animals that includes insects, spiders, and crustaceans. Some crustaceans, such as shrimp, crabs, and lobsters, live in the water.

* Echinoderms: Echinoderms are a group of marine invertebrates that includes starfish, sea urchins, and sea cucumbers.

* Tunicates: Tunicates are a group of marine invertebrates that includes sea squirts and salps.

* Bryozoans: Bryozoans are a group of marine invertebrates that form colonies of tiny animals that live in a protective case.