MOLLUSKS

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MOLLUSKS

• Clams, snails, slugs, chitons, octopuses
• 2nd only to arthropods in of species

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Main characteristics of Mollusks

• Soft body usu. covered by calcium carbonate shell
• Broad, flat, muscular foot
• Mantle

• Body organs concentrated in visceral mass above
  foot
• Radula (except in filter feeders)

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Gastropods Stomach-footed mollusks

• Marine gastropods have gills
• Head with tentacles
• 2 simple eyes

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SNAILS
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WHELK
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CONCH
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Nudibranchs
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Bivalves

• Clams, oysters, scallops, mussels
• Have 2-part shell
• Suspension feeders
• Incurrent siphon brings in water
• Mucus of gills catches food particles
• Excurrent siphon brings waste water out

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Cephalopods Head-footed Mollusks

• Fast-swimming predatory animals
• Mouth surrounded by tentacles or arms
• Mantle is thick and muscular
• Well-developed eye sees images
• Intelligent
• Ink sac
• Chromatophores

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Just for Fun

• Giant Squid has largest eye in animal kingdom
• Size of basketball
• Plural of octopus octopuses
• G\Marine Biology\Invertebrates\Octopus.asf
• G\Marine Biology\Invertebrates\Giant_Squid.asf