Phylum Platyhelminthes ("Flat Worm")
Description
Phylum Platyhelminthes is home to the flatworms, which consist of Tapeworms, Planarians and Flukes. They are either aquatic or parasitic. Their bodies are flat and ribbon-like, and are bilaterally symmetrical. They have three tissue layers and organs. Their nervous system is central and receives info from sensory organs. They possess a gastrovascular cavity and are acoelomates. They were the first to develop a head, and have the earliest version of one.