Sunday, September 11, 2011

Characteristics of Annelida


1)    They may be marine or freshwater living ,terrestrial, burrowing ,sedentary or free living.
2)    Body is triploblastic ,bilaterally symmetrical worm shaped.
3)    Body is round and segmented.
4)    Their body is covered by cuticle.
5)    Some of them have appendages which are not jointed.
6)    They move by paired setae arranged in segment.
7)    They have alimentary canal with mouth and anus.
8)    Excretion takes from nephridia which are present in each segment.
9)    Nervous system consist of a pair of cerebral ganglia, a brain and two nerve cord with ganglia in segments.
10)They are usually hermaphrodite but some are also unisexual.
11) Usually they reproduce sexually but asexual reproduction also occure in some of them.

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