animals invertebrats

1. not body protection

1.1. worm

1.2. sponge

1.3. meduse

2. artropods

2.1. insects

2.2. aracnids

2.3. custracis

2.4. mirapods

3. presents

3.1. body protection

3.1.1. whith

3.1.1.1. pell dura

3.1.1.2. closca

3.1.1.2.1. moluscs

3.1.1.3. espines o plaques

3.1.1.3.1. equinoderms

4. not have

4.1. spine