The circulatory system is obviously not present in the organisms in this phylum, therefore, the species in this phylum obtain a pseudocoelom, a space in the body of a multicellular organism that is filled with fluid that supplies the body with various substances. Because there is an absent of the circulatory system, the metabolic waste is excreted by two ducts that the species have. This phylum also includes animals such as: roundworms, gastrotrichs, and also trichina worms.