Mollusks
Mollusks include:
!   Gastropods
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Is the largest group of mollusks; includes snails and other
single shelled organisms, ; may live in freshwater, marine or
terrestrial environments
!   Bivalves
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Includes clams, oysters, mussels and scallops; are filter feeders
living in freshwater or marine environments
!   Cephalopods
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Includes squids and octopuses; can have either an external
(nautiluses); internal (squids) or no shell (octopuses)
Characteristics and Special
Organs
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Foot –
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Mantle –
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An outgrowth of the animal that drapes over the body
Excretes the shell
Can also be used for: respiration, waste disposal, and sensory
functions
Radula!  
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All mollusks have a muscular foot used for locomotion, digging
and anchoring
Most mollusks have a rasping or drilling organ used in feeding
Open circulatory system
Mollusk Anatomy