- Body is 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.
- Most forms are parasitic but some are free- living in soil or water.
- They are devoid of the circulatory system and respiratory system.
- They exhibit tissue level organization.
For Example: Ascaris and Wuchereria