- Arthropods - Crabs, Lobsters and More (10)
- Cnidarians - Corals, Jellyfish, Anemones (7)
- Echinoderms - Sea Stars, Urchins and More (3)
- Mollusks - Phylum Mollusca (12)
What Is An Invertebrate?
A common definition of invertebrate is "an animal without a backbone, or spine." But the more correct definition is an animal without a notochord. A notochord is a rigid rod made of cartilage that is present in all chordates. Here you can learn what invertebrates look like, where they are found, and more.
Learn about the sea mouse, a type of worm.