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General characters of phylum mollusca with point

 • Body type : Body is soft , unsegmented ,     Bilate rally symmetrical. 

 • Body parts : Body consist of head , foot, mantle and   visceral mass.

 • Shell : Body is protected by exoskeleton.   calcareous  shell secreted by mantle.

• Head : Head is distinct , bearing the mouth and provided with eyes , tentacles and other sense organs.

• Respiratory organs : Respiratory organs consist of numerous gill or ctenidia usually provided with osphradium at the base.

Lung is developed in terrestrial forms.

• Body cavity : Body cavity is haemocoel.

• Radula : pharynx contains a raspindg organ, the Radula .

• Excretory organs : Excretory organs consists of pair of metanephridia.

• Sex : Sexes usually separate (dioecious) but some are hermaphroditic.

• Fertilisation : Fertilisation is external or internal.

• Development : Development is either direct or with metamorphosis through trochophore stage.

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