Howstuffworks "Worms"

Annelid

Annelid, a member of a large phylum of worms, most of whose members have segmented, tubular bodies.

Ascaris

Ascaris, a genus of parasitic roundworms. Members of this genus are widely distributed, and are especially numerous in warm, moist climates.

Earthworm

Earthworm, a long, slender worm. It is found in damp soils of regions having moderate or warm climates.

Eelworm

Eelworm, a common name for a free-living (that is, nonparasitic) or plant-parasitic roundworm.

Flatworm

Flatworm, a worm with a soft, flat body. Some flatworms live in water, chiefly in the sea, but most are parasites that live in the bodies of other animals.

Fluke

Fluke, a flatworm that lives on or in other animals. Some flukes live on a single host.

Hairworm, a long, slender worm found in many ponds or quiet streams. Hairworms are sometimes called horsehair worms and horsehair snakes because it was once thought they were worms or tiny snakes that developed from horsehairs that fell into water.

Hookworm

Hookworm, a roundworm that lives as a parasite in the intestines of man and other animals.

Leech

Leech, or Bloodsucker, a bloodsucking annelid worm. Most leeches live in the sea.

Pinworm

Pinworm, a small roundworm that lives as a parasite, most often in the digestive tract of human beings.

Planarian

Planarian, any of several free-living (nonparasitic) worms. The planarian is the simplest of all flatworms.

Ribbon Worm

Ribbon Worm, any of about 900 species of worms that typically live on seacoasts and in the sea.

Roundworm

Roundworm, or Nematode, a slender, cylindrical worm. Roundworms are of worldwide distribution and are found in freshwater and saltwater, in plants and animals, and in the soil.