General Characteristics
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Body Wall
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Digestion and Nutrition
- lack digestive cavity
- blind cavity varies from a simple, unbranched chamber to a highly branched system of digestive digestion tubes
- some digestive tracts are lobed
Exchanges with the Environment
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Taken From:
http://skepticalsquirrel.wordpress.com/2012/07/26/more-turbellaria-moving-eating-mating/ |
- no respiratory organs
- exchanges gas and metabolic wastes with diffusion through body wall
- protonephridia - an excretory organ with networks of fine tubules that run the length of the organism, along each of its sides
- flame cells - an excretory organ that has numerous, fine side branches of the tubules originate in the parenchyna as tiny enlargements
Nervous System and Sense Organs
- nerve net
- centralized nerve net with cerebral ganglia
- most have nervous system consisting of a subepidermal nerve net and several pairs of long nerve cords
- auricles - sensory lobes that may project from side of head and that detect touch, water currents, and chemicals
- Ocelli - Two eye spots that orient the animal to the direction of light
Reproduction and Development
Asexual
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Taken from:
http://sharon-taxonomy2009-p2.wikispaces.com/file/view/planarian.jpg/99189887/planarian.jpg |