Does a flatwarm have a pseudocoelom?

Flatworms, belonging to the phylum Platyhelminthes, do not have a pseudocoelom. They are acoelomate animals, meaning they lack a body cavity between the digestive tract and the outer body wall. Instead, their space between tissues is filled with a solid tissue called mesenchyme. This distinguishes them from organisms that do possess a pseudocoelom, such as nematodes.