1. Phylum : Platyhelminthes The Flatworms Acoelomates

2. Classes of Platyhelminthes Class Turbellaria (e.g., Planaria) Class Turbellaria (e.g., Planaria) The Flukes The Flukes Class Trematoda (e.g., Fascioloaris, Clonorchis) Class Trematoda (e.g., Fascioloaris, Clonorchis) Class Cestoda (e.g., Taenia) Class Cestoda (e.g., Taenia)

3. General Characteristics Free-living or parasitic Free-living or parasitic Bilaterally symmetrical, and dorsoventrally flattened Bilaterally symmetrical, and dorsoventrally flattened First animals with 3 germ layers - triploblastic First animals with 3 germ layers - triploblastic Ectodermis Ectodermis Mesodermis Mesodermis Endodermis Endodermis Epidermis has cilia or cuticle Epidermis has cilia or cuticle Coelom lacking (acoelomate) Coelom lacking (acoelomate)

4. General Characteristics cont. Digestive system incomplete Digestive system incomplete Excretory system – protonephridia Excretory system – protonephridia Nervous system – ladder-like Nervous system – ladder-like Respiratory, circulatory, and skeletal system lacking Respiratory, circulatory, and skeletal system lacking Most monoecious Most monoecious Some have fragmentation and regeneration (Asexual) Some have fragmentation and regeneration (Asexual)

5. Figure 14.01

6. Class Turbellaria Freeliving Flatworms Free-living Free-living Ciliated epidermis Ciliated epidermis Mouth ventral Mouth ventral Digestive system incomplete Digestive system incomplete

10. Dugesia w.m. Eyespots Auricle

12. Figure 14.02 Freshwater Flatworm

13. Marine Flatworms

14. Marine Flatworm

15. Trematoda and Monogenea The Flukes Endoparasites Endoparasites Cuticle covering body Cuticle covering body Oral sucker surrounds mouth Oral sucker surrounds mouth Ventral sucker used for attachment Ventral sucker used for attachment Complex life cycles Complex life cycles

16. Clonorchis

17. Clonorchis

18. One Intermediate host Shistosoma – Blood Fuke

19. Two Intermediate hosts Clonorchis – Chinese liver fluke

20. Cestoda The Tapeworms Endoparasites Endoparasites Body consists of proglottids and scolex Body consists of proglottids and scolex Proglottids snapshots of development Proglottids snapshots of development Scolex has structures for attachment (Hooks, suckers and rostellum) Scolex has structures for attachment (Hooks, suckers and rostellum) No digestive system No digestive system

21. Figure 14.18

22. Figure 14.19

23. Taenia scolex

24. Figure 14.20 Mature Proglottids

25. Taenia – can get to 30+ feet long

26. Hydatid Cysts of dog tapeworm in human brain A case of a parasite in the wrong host