THE  MOLLUSCA

EUCOELOMATES
body cavity completely lined with a mesoderm [fig. 16.11c]

PHYLUM MOLLUSCA

Class GASTROPODA

  • 35,000 species of snails and slugs [Fig. 21.8, 21.9]
  • marine, freshwater and terrestrial; mainly herbivores and carnivores
  • coiled shell (may be lost)
  • torsion [Fig. 21.7]: note position of gill and mantle cavity and anus in the figure from BIODIDAC
  • gills in aquatic species; vascularized mantle in terrestrial forms
  • more about gastropods from the University of Michigan

 

Class BIVALVIA

  • 30,000 species of clams, oysters, scallops, mussels
  • paired, hinged shells [Fig. 21.10]
  • mainly filter feeders [Fig. 21.12, 21.13]: gills & siphons
  • sedentary, infaunal and epifaunal, scallops semi-nektonic
  • more about bivalves from the University of Michigan

 


Class CEPHALOPODA

  1. Nautiloidea
    1. pearly nautiluses [Fig. 21.17a]

 

  1. Coloidea
    1. squids [Fig. 21.18], cuttlefish [Fig. 21.17b], and relatives
  2.  

  1. octopuses [Fig. 21.1]
 

Class Polyplacophora

 

Class Scaphopoda

 

Class Monoplacophora

 

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