Phylum Mollusca

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Phylum Mollusca
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Characteristics of Mollusks

• Soft bodies
• Most have internal or external shell
• Most are bilaterally symmetrical (although they
  may not look like it)
• Well developed respiratory, excretory,
  circulatory, and digestive systems
• Similar to annelids in that they have a
  trochophore larvae

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More Mollusk stuff

• Are not segmented
• Greatly reduced coelom
• Many are slow moving (Cephalopods are the
  exception)
• Marine, fresh water and terrestrial
• Three primary body regions
• Head-foot
• Visceral Mass
• Mantle

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Five major Classes

• Class Bivalva mussels, clams, oysters
• Class Polyplacophora Chitons
• Class Scaphopoda Tooth or Tusk shells
• Class Gastropoda Snail, Slugs
• Class Cephalopoda Squid, Octopus, Cuttlefish

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Clam Life cycle
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Clam dissection
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bioweb.uwlax.edu/.../ mussel_dissection_2.htm

• 1.  Umbo  2.  Hinge ligament  3.  Lateral hinge
  teeth  4.  Cardinal hinge tooth  5.  Posterior
  adductor muscle  6.  Anterior adductor muscle 
  7.  Heart  8.  Pericardial cavity (coelom)  9. 
  Gill 10. Digestive gland 11. Gonad 12. Portion of
  the intestine 13. Foot 14. Mantle

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Squid dissection

• http//biog-101-104.bio.cornell.edu/BioG101_104/tu
  torials/animals/squid_stuff/male_premise.html