Platyhelminthes

Triploblastic

Endoderm, ectoderm, and cellular mesoderm

Acoelomate

No true tissue

Cephalization

Nervous tissue and sensory organs closer at the front end of the animals body

Blind gut

Complex gut ( no anus)

Hermaphroditic

Complex reproductive system

Protonephridia

Excretion and osmoregulation

Gas exchange

Uses entire body surface

Class Turbellaria ( free-living flatworms)

• free living

• Aquatic

• The mouth leads to the pharynx (throat)

• Epidermis ciliated (move things down)

• Gut = diverticula( branched intestine)

• Polycaladia( multibranched)

• Tricaldia( gut 3 branched)

Class Monogenea ( flukes)

• Ventral sucker

• Anterior prohaptor ( feeding)

• Posterior hooked opisthaptor ( secure stay)

• Parasitic to one host

• Ectoparasitic on fish

Class Trematoda ( flukes)

• Oral sucker and acetabulum

• Lack of prohaptor and opisthaptor

• Tegument ( protective outer layer)

• Parasitic to 2 or 3 host

  • Intermediate host ( mollusc)

  • 2nd host

  • definitive host ( vertebrate)

Class Cestoda ( tapeworms)

• Endoparasitic of the intestine of verts

• Teguments

• Scolex( hook for feeding)

• Strobila is composed of proglottids ( reproductive area)

• Digestive tract absent