1. Platyhelminthes Flatworms Tapeworms Flukes

2. PHYLUM PLATYHELMINTHES Bilateral Triploblastic Acoelomate –Gastrovascular cavity Cephalization Ladder-like nervous system Protonephridia with flame cells

3. Fig. 21.15

4. Symmetry

5. Traditional View Continues Acoelomate - Pseudocoelomate vs Coelomate Aceolomate no space between tissue layers, no cavity

6. Protonephridia with Flame cells

8. Class Turbellaria Free living flatworms Example: Dugesia (Planaria)

9. External Anatomy

11. Ladder-like nervous system No real “brain”, but anterior ganglia

12. Ladder Nervous System

13. Fig. 21.18

17. Planaria c.s.

18. Class Trematoda Flukes All parasitic Possess two suckers Have complex life cycles Need multiple hosts

20. Chlornorchis sinensis

21. Fasciola hepatica w.m.

22. Schistosoma sp. w.m.

24. Schistosomiasis

25. eosinophylls attacking a larval fluke.

26. Class Cestoda Tapeworms Scolex and proglottids Segmented

28. Diplydium caninum

29. Scolex Anatomy Rostellum Suckers Neck

31. Tapeworm development

34. Proglottid anatomy Uterus Genital pore Ovary Testis

35. Echinococcus granulosus w.m.

36. Hydatid cyst Capsules of scolices

37. Hydatid Cyst Disease