Skeletal System
Nematodes are covered in a hard shell called a cuticle. This protects their bodies. Nematodes are much like snakes in that their cuticle sheds as they grow and they grow a new one once the old one is shed. The cuticle is stiff and causes the nematode to have to whip from side to side as it swims.
Here you can see the nematode's cuticle.
