They are dorsoventrally flattened
It is also called flatworms
They are 2D in shape
General characters
✓ Habit and habitat:-they can be Indo parasite ,aquatic and terrestrials ,Free living
✓ Level of organisation:- organ system
✓ Symmetry:- bilateral symmetry
✓ Germ layer and body plan:-triploblastic ,blind sac
✓ Coelom:-Acoelomatis
✓ Segmentation:-pseudo segmentatation eg. Tapeworms, proglottid
Typical characters
Parasitic adaptation:-a) hook and suckers
•adhesion
•suck nutrition
b) cuticular lining:-this protect them from action of enzymes
c) absence of digestive system:-the take nutrition directly from host .
Digestion:-extracellular type of digestion-incomplete digestion system
Respiration and circulation:-general body surface (diffusion)
Excretion:- ammonotelic
Osmoregulation
Flame cell/solenocytes/protonephridia
Nervous system and sense organ:- a) sense organ:-chemoreceptor
b) nervous system:-ventral double, solid nerve cord
Reproduction:- a) sexual reproduction:-they are hormoproditis. internal reproduction
b) asexual reproduction:-regeneration and fragmentation ,strobilation
Development:-they have indirect development because huge larva
Examples
Planuria
Blood fluke
Dog tapeworm
Beaf tapeworm
