Phylum Platyhelminthes



Examples: Dugesia tigrina (planaria), Opisthrochis sinensis ( human liver fluke), Fasciola hepatica ( sheep liver fluke), Taenia pisiformes (dog tapeworm), Taenia soleum (pig tapeworm), Schistosoma mansonii ( blood fluke).



  1. Bilateral sumetry.
  2. Acoelomate.
  3. hermaphroditic.
  4. Tissue level of organization.
  5. Tripbloblastic.
  6. Dorsoventrally flattened.
  7. One opening into gastovascular cavity.
  8. With cephalization forming a primitive brain and a ladder type nervous system.


Class Turbellaria-example planaria.


  1. Mostly free living.


Class Trematoda-flukes


1.      All parasitic.

2.      with suckers.

3.      Specialized reproductive systems and a complex life history.


Class Cestoda-tapeworms


1.      All endoparasites.

2.      Head containing hooks and suckers.

3.      Body made up of segments called proglottids each containing reproductive organs.

4.      No digestive system/