1. Primitive Critters

3. Porifera

4. Porifera - Body Plan

5. Cnidaria - body forms

17. Ctenophora

20. Platyhelminthyes

25. Parasitic Flatworms - Tapeworms Parasites have adaptations for attaching to their host as well as adaptations for evading the hosts immune defenses Tapeworms also have intermediate hosts. In humans the intermediate host may be a pig or cow. Fleas are the intermediate host of the dog tapeworm.

26. Parasitic Flatworms - Flukes Parasites often cause chronic debilitating diseases Their life cycles are often complex and may involve more than one host

27. Nemertae Also called proboscis worms. The extendable probocis is used to capture prey. Their body is much like a flatworm, but with an intestine, anus, and circulatory system.

28. Nematoda Nematodes, also called roundworms have a one way digestive system and a tube within a tube body design. The space between the two tubes is a type of body cavity called a pseudocoelom.

29. C. elegans

30. Trichina

32. Annelida - Segmented Worms

33. Playground Playmate?

36. Trochophore Larva

37. Mollusk Body Plan

47. Peripitus

48. Arthropoda

63. EARLY DEVELOPMENT