Hookworms are Nematodes, which are worm-like creatures. They have an exterior layer of strong, flexible, and a noncellular cuticle. Nematodes and/or any other species in this phylum do not contain a circulatory system. Much like the Platyhelminthes phylum, they obtain nutrients and get rid of wastes through diffusion of body fluids in a pseudocoelom, a single body cavity filled with fluids.