1) They are mostly marine ,few freshwater or terrestrial forms.
2) They have visceral mass twisted.
3) They have mantle cavity which opens anteriorly in front of the visceral mass.
4) They generally have conical and spirally coiled shell with an operculum.
5) They have distinct head with snout bearing a pair of tentacle and a pair of eyes.
6) They have muscular foot that forms the ventral part of the body.
7) They may have ctenidia or gills and if present are situated in the front of the heart.
8) Sexes are separate
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