Flatworms are in their own phylum. Flatworms are much more complex that sponges or jellyfish and more animal-like.
Flatworms have a nervous, digestive and reproductive systems.
On the right is a planarian which is found in freshwater ponds. Flatworms Flatworms are bilaterally symmetric. This means they have identical left and right halves as in humans. Flatworms have brains.