Platyhelminthes
Platyhelminthes, other wise known as flatworms, are a phylum of the Animala kingdom. They contain mostly parasitic worms with the exception of the Turbellaria class which has mostly free living organisms. Like the nematodas, the platyhelminthes has no skeletal system and most free living worms are predators and live in water or shaded, humid environments.
m.youtube.com/results?q=phylum%20platyhelminthes