Bilateral symmetry, organ-level of organization, true coelom or pseudocoel
Pseudocoel, what is "pseudo" about it?
Body cavity not entirely lined with peritoneum
One-way digestive tract
mouth empties into short muscular pharynx, which sucks food into the ribbon-like intestine which leads to the anus.
longitudinal, move via side-to-side bending
large phylum of beneficial, free-living roundworms as well as many parasitic worms such as Ascaris, pinworm, hookworms, and heartworms.
not a worm, a fungus