Type Nemathelminthes презентация

Type Nemathelminthes
~24 000 species
Free-living and parasitic
80 mcm – 8 m
Bilateral simmetry

Unsegmented body
Schizocoel – body cavity
Sexual dimorphism
No respiratory or circulatory system
Excretory system – protonephridia/skin glands/none
They have anus (first time in the world history)

Class Gastrotricha
160 species. 1-1,5 mm. Live in fresh water
Ciliated epithelium on their ventral side
They are believed to be intermediate between Turbellaria (freeliving flatworms) and roundworms

Класс Nematoda

Human ascarid life cycle

Pinworm
Only in humans!

Trichinella

Whipworm

Ankylostoma

Guinea worm

Class Nematomorpha (hair-worms)
Parasites in insects
Very thin, up to 1,5 m long
No excretory system
1 nerve cord