Platynelminthes
The phylum includes three classes:
- Turbellaria (free-living flatworms)
- Trematoda (flukes)
- Cestoda (tapeworms)
- Turbellaria (free-living flatworms)
- Trematoda (flukes)
- Cestoda (tapeworms)
Turbellaria
Free-living flatworms, or turbellaria, have simple, leave-like bodies on which they glide upon by fine hairs or by ripples of
contracting muscles. A flexible tubular proboscis traps prey such as small crustaceans and mollusks.The digestive system ends blindly without any anus.
contracting muscles. A flexible tubular proboscis traps prey such as small crustaceans and mollusks.The digestive system ends blindly without any anus.
Trematoda
Trematodas, or flukes, are a parasitic flatworm. There are an estimated 18,000 to 24,000 species of trematoda, nearly all of which being vertebrates. They possess an excretory system that is mainly for the purpose of osmoregulation, or the desire to achieve homeostasis. This requires two or more protonphridia--kidney like organs that lie on each side of there body. They form collecting ducts which then connect with each other at a single bladder. The waste is released through one or more pores from the animal's body.
Cestoda
A more common and recognizable term for cestoda would be tapeworm. Most people simply recognize tapeworm as a parasite, which it is. Tapeworms can grow up to forty feet within the human body. Wastes make their way through the cestoda's long body, dropping off at the end.