> Animal Profiles> Invertebrates> Flatworms

Introduction to the Platyhelminthes
Did you know some animals belonging to the phylum Platyhelminthes are parasitic while others are free-living? Find out more about the complex life histories of these animals in this article.

Phylum Platyhelminthes
Learn about four classes of Platyhelminthes: Turbellaria, Monogenea, Trematoda, and Cestoda.

Ancestral Flatworms
Find out about the evolutionary history of flatworms and how their development and adaptations lead the way for later organisms.

Marine Flatworm Galleries
Discover the diversity and aesthetics of flatworms in this visual catalog of species from all around the world.

The Oldest Living Animals with Bilateral Symmetry
Scientist have identified the oldest living group of flatworms and in doing so have found the oldest living ancestor of all animals who possess bilateral symmetry.