False!
The marine flatworms (polycladids) are the greatest of the free-living flatworms. Most of them are about 1 centimeter in length, but there are some species that can reach lengths of 15 centimeters. They belong to the Phylum Platyhelminthes or flat worms. A great number of species are parasites, but there are some species that are free-living and they belong to the group of Polycladids.
