| A | B |
|---|
| sessile | Adjective used to describe animals that don't move from place to place. |
| radial symmetry | Animal body plan that can be divided along any plane through a central axis into roughly equal halves (ex: hydra and jellyfish) |
| bilateral symmetry | Animal body plan that can be divided down its length into left and right halves. |
| anterior | The front or head end of an animal. |
| posterior | The rear or tail end of an animal. |
| dorsal | The "back" surface of an animal. |
| ventral | The belly surface of an animal. |
| acoelomate | Animals that have a three cell layers but no body cavity. |
| pseudocoelom | Animals that have a fluid filled cavity partly lined with mesoderm. |
| coelom | Animals that have a fluid filled cavity COMPLETELY lined with mesoderm. |
| exoskeleton | Hard, waxy covering on the outside of the body that provides a framework for support and movement. |
| endoskeleton | Internal skeleton that provides support inside an animals body. |
| invertebrate | Animal that DOES NOT have a backbone. |
| vertebrate | Animal that has a backbone. |
