NEMATODA
Description: These animals have a cylindrical tapered bodies and range is length from few millimeter to a meter and live in diverse habitats. Free-living nematodes eat microorganisms; other nematodes may feed on decaying organic material.  Vinegar eel is a common free-living nematode. All roundworms have a bilateral symmetry and a mouth and an anus.

Examples
1. Strongyloides