ASCARIS

any of a genus of worms (order Ascaridida, class Nematoda) that are parasitic in the intestines of various terrestrial animals, chiefly herbivores. They are typically large worms characterized by a mouth surrounded by three lips. The species Ascaris lumbricoides is probably the most familiar parasite in humans. An almost identical worm, often called A. suum, occurs in pigs. It is, however, not certain that this species is distinct from the one that infests humans. See ascariasis.