Phylum: Platyhelminthes

A. Hypothetical Origins

i. Paedomorphosis

B. General Characteristics

i. Triploblastic

ii. Acoelomate

iii. Parenchyma

2. Phylum Platyhelminthes

A. Anatomy - Bilateral symmetry.

i. Acoelomate

ii. Unsegmented

iii. Cephalization

a. Eyespots

iv. Excretory System

a. Protonephridia (Flame Cells)

v. Reproduction

• Monoecious (Hermaphroditic)

• Larvae

vi. Digestion

B. Parasitism

i. Anatomical Changes

a. Digestion

b. Reproduction

ii. Life Cycle Changes

a. Intermediate Host

b. Definitive Host

C. Classes

i. Class Turbellaria

a. General

b. Cells of the Body Wall

• Rhabdites

• Adhesive glands

• Releaser Glands

c. Locomotion

d. Digestion

• Pharynx

• Gastrodermis

e. Gas and Waste Exchange

f. Water Regulation

• Protonephridia

• Flame Cells

• Nephridiopores

g. Nervous System

• Nervous System Variations:

* Order Acoela

* Order Polycladida

* Order Tricladida

• Auricles

• Ocelli

h. Reproduction

• Asexual via Transverse Fission

* Zooids

• Sexual

* Monoecious

a. Opisthaptor

iii. Class Trematoda (Flukes)

• Tegument

a. Subclass Aspidogastrea

• Opisthaptor

b. Subclass Digenea

• Suckers

* Oral Sucker

* Acetabulum

• Life Cycle Steps

* Eggs

* Sporocyst

* Radiae

* Cercaria

* Metacercaria

* Adult
• Examples

* Fasciola hepatica

* Clonorchis sinensis

* Schistosoma sp.
iv. Class Cestoda

• digestion

• Proglotid

a. Subclass Cestodaria

b. Subclass Eucestoda

• Scolex

* Rostellum

• Neck

* Gravid Proglottids

• Taeniarhynchus saginatus

• Taenia solium

• Diphyllobothrium latum

2. Phylum Nemertea (Rhynchocoela)

A. Complete Digestive Tract

• Proboscis

• Rhynchocoel

B. Closed Circulatory System

D. Reproduction

i. Dioecious