The nematode body is also bilaterally symmetrical and triploblastic. However, the body is cylindrical rather than flattened. There are tissues, but no real organs, although a sort of body cavity or a pseudocoelom, is present. These are very familiar as parasitic worms causing diseases, such
as the worms causing elephantiasis (filarial worms) or the worms in the intestines (roundworm or pinworms).
Fig – Wuchereria
Fig – : Nematoda (Aschelminthes)