Nematode

Members of the phylum Nematoda, commonly called roundworms.

Nematodes have tiny cylindrical thread-like bodies that are pointed at both ends and covered with tough cuticle or skin-like membranes. Many are free-living dwellers in soil and water; others, like hookworms, Ascaris, pinworms, trichina worms, and filaria worms are parasites of man, animals, and plants.