invertebrates

1. no internal skeleton

1.1. animals

2. live in water or soil

2.1. worms

3. live in the sea

3.1. sponges

3.2. celenterats

3.3. echinoderms

4. molluscs

4.1. screws

4.2. bilvalves

4.3. cephalopods

5. arthropods

5.1. external skeleton

5.1.1. crustaceans

5.1.2. arachnid

5.1.3. miriápodos

5.1.4. insects