| Turbellaria (Planarians) | Trematoda (Flukes) | Cestoda (Tapeworms) |
| Non-parasitic free living worms, called Planarians. Terrestrial, marine or freshwater. Body unsegmented. Suckers absent. Chemo and Photoreceptors are present. Body unsegmented, flattened and covered in ciliated epidermis. Mostly hermaphroditic. Some reproduce asexually. Development usually direct. | Ecto/Endoparasites. Called Flukes Thick tegument but no cilia. Larva have cilia. Body unsegmented. Sucker and hook are sometimes present. Mostly hermaphroditic. Development direct or indirect. | Endoparasitic. Called Tape-worms Scolex with suckers or hooks or both. Neither adult nor larva have cilia. No alimentary canal, no sense organs. Hermaphrodite. Life cycle complex with multiple intermediate hosts. |
| e.g. Euplanaria, Geoplana, Bipalium | e.g. Polystoma, Fasciola | e.g. Taenia |