Is a ascaris a flatworm

Ascarids are not vertebrates; they are of the genus Ascaridae, parasitic nematodes generally thought of as intestinal roundworms. Parascaris equorum, the equine roundworm and probably the most common Ascarid, infects horses, donkeys, and zebras, but is not known to infect humans or other animals. Ascarids are usually species-specific -- Ascaris lumbricoides affects humans and causes the disease ascariasis while Ascaris suum infects pigs, but there is a possibility that these two species may cross-infect humans and pigs.