Phylum Platyhelminthes

• Phylum Platyhelminthes (Flatworms) - Flattened, bilaterally symmetrical worms with no body cavity
• Symmetry of Platyhelminthes

  Bilateral symmetry
• Grade of organization of phylum Platyhelminthes

  Organ and organ system
• Digestive system of phylum Platyhelminthes

  Incomplete
• Germinal layer of phylum Platyhelminthes

  Triploblastic
• Coelom of phylum Platyhelminthes

  Acoelomate
• Habit and habitat of phylum Platyhelminthes

  Mainly aquatic

  Mostly endoparasite some are free living
• Circulatory and respiratory systems of phylum Platyhelminthes

  Absent
• Reproductive system of phylum Platyhelminthes

  Asexual and sexual

  hermaphrodite

  Internal fertilization

  Indirect development many larval stages
• Unique features of phylum Platyhelminthes

  Unsegmented (except tape worm)

  Dorso ventrally flattened body

  Excretion by flame cells

  Hooks and suckers are present in parasitic forms.

  Some absorb nutrients from host's surface.

  Presence of cuticle
• Examples of phylum Platyhelminthes

  Taneria (Tape worm)

  Liver fluke (Flaciola)

  Planaria