Platyhelminthes General Characteristics, Classification and Examples

After reading this article you will learn about Platyhelminthes General Characteristics and classification.

Platyhelminthes General Characteristics

Most are Parasitic on other animals and some are free living forms
They have dorsoventrally flattened body hence are called flat worms
Body is formed from three germinal layers
Locomotory organs are absent in these animals but adhesive organs like suckers, hook are present in parasitic form
On the body wall of parasitic animals a thick cuticle is present called tegument
These thick cuticle protects the parasite from the digestive enzymes of the host
Muscles in the body wall are mesodermal
Below the epidermis longitudinal, circular and oblique muscles are present
Digestive system incomplete or absent
Skeleton, respiration and circulatory system are absent
They respire through body surface and anaerobic respiration is found in parasite
Nervous system is ladder like, consist of a nerve ring and longitudinal nerve cords
Excretion occurs through specialized cells called flame cells or solenocytes
Some members possess high regeneration capacity
Sense organ are better developed in free living forms (Cephalization)
Asexual reproduction occurs by fragmentation in many freshwater flatworms
In sexual reproduction they are hermaphroditic meaning each individual produces eggs and sperm
Fertilization is internal and cross fertilization is predominant
Life cycle is indirect or complicated with one or many larvae

Class 1. Turbellaria

Class 2. Trematoda

Class 3. Cestoda

For more detailed information about Animal Kingdom, visit YouTube Channel.