Ascaris lumbricoides in common roundworm of

Ascaris lumbricoides is the "giant roundworm" of humans, growing to a length of up to 35 cm (14 in). It is one of several species of Ascaris. An ascarid nematode of the phylum Nematoda, it is the most common parasitic worm in humans. The eggs hatch in the intestines, burrow through the gut wall, and migrate to the lungs via the blood.