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Pseudobiceros bedfordi (Laidlaw 1903)

Persian Carpet Flatworm

Cheryl Tan Kay Yin (2013)



Fact Sheet



Physical Description


Life History & Behaviour


Phototaxis Experiment


Feeding & Nutrition

Anatomy & Physiology

Skeletal System

Sensory System

Muscular System

Digestive System

Internal Transport System

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links

Internal Transport System

A. Internal Transport

Turbellaria do not have circulatory and respiratory organs hence their body plan is confined to a dorso-ventrally flattened body with a thin epidermal layer. This thin epidermal layer allows respiratory gases such as carbon dioxide and oxygen to be exchanged via diffusion through their body wall.

B. Excretion:

As turbellarians have no circulatory to excrete waste products from their system, they rely on specialized cells known as terminal cells that are found along the periphery of the turbellarian body.This diffused network of ciliated terminal cells form the protonephridia –a simplified kidney system in turbellaria that perform the function of excreting waste products from the system.

Figure 1. Protonephridial system in turbellarians ( except acoelomorphs) spans the entire body of the flatworm to ensure short diffusion distances for exchange of gases and excretion of waste products. Terminal cells (A) are present all around the body to facilitate the gaseous exchange and waste excretion process.