1. KINGDOM ANIMALIA Phylum Platyhelminthes

2. Phylum Platyhelminthes
Members of the four classes of the phylum are known as the “flatworms.”

3. Members of the Phylum Platyhelminthes
…are bilaterally symmetrical.
…are acoelomates with only one internal space.
…have an organ-system level of organization
…are hemaphroditic.
…range in size from 1-2 mm to several meters.

4. Four Important Platyhelminthes Classes
1. Class Turbellaria
Mostly free-living flatworms
Either carnivores or scavengers
Example: Dugesia

5. Four Important Platyhelminthes Classes
2. Class Monogenea
Typically found as parasites on fish
Single generation in life cycles
Example: Gyrodactylus

6. Four Important Platyhelminthes Classes
3. Class Trematoda
All parasitic flukes
Most are internal parasites of vertebrates with complex life cycles
Example: Schistosoma

8. Four Important Platyhelminthes Classes
4. Class Cestoda
Most are internal parasites living in the gastrointestinal tracts of vertebrates
No digestive system
Tapeworms-“the ultimate parasites”