Mollusca molluscs, mollusks, soft bodied animals mostly with an internal or external calcareous shell --[researchers ToL ummzADW links] Aplacophora solenogasters, deep-sea worm like animals --[ummzADW links] Polyplacophora modern chitons (Chiton, Tonicella) --[ummzADW links] Monoplacophora mostly fossil, living species not discovered until 1977 (Neopilina) --[ummzADW links] Gastropoda slugs, snails & their relatives --[ ummzADW links] Prosobranchia snails (Buccinum, Calliostoma, Cerithium, Conus, Cypraea, Haliotis, Littorina, Murex, Oliva, Patella, Strombus, Thais) Heterobranchia (Architectonica, Nerinea, Pyramidella, Turbonilla) Opisthobranchia slugs Anaspidea (=Aplysiomorpha) (Aplysia -- sea hares) Cephalaspidea (Acteon) Gymnosomata (Clione) Notaspidea (Pleurobranchaea) Nudibranchia (Acanthodoris) --[dedicated site] Pulmonata Archaeopulmonata (Melampus) Basommatophora (Biomphalaria, Bulinus, Lymnaea) Stylommatophora land snails (Achatina, Arion, Helix, Liguus, Limax, Partula, Polymita, Succinea) Cephalopoda cephalopods --[dedicated site researchers ToL ummzADW links] Nautiloidea once abundant, Nautilus is now the only genus with living representatives Ammonoidea ammonites & their relatives, only known from fossils (Ammonites) Coleoidea group containing all living cephalopods other than Nautilus Belemnitida belemnites, fossils (Belemnites, Gonioteuthis) Octopoda octopods, octopuses, devilfishes (Argonauta, Eledone, Octopus) Sepiida cuttlefish; often grouped with squid as Decapoda (Euprymna, Sepia, Spirula) Teuthida squid; often grouped with cuttlefish as Decapoda (Illex, Loligo, Sepioteuthis, Todarodes) Vampyromorpha vampire squid Bivalvia bivalves, pelecypods, lamellibranchs, includes clams, mussels, oysters etc with laterally hinged bivalve shells (Arca, Cardium, Crassostrea, Dreissena D. polymorpha -- zebra mussel, Macoma, Mactra, Modiolus, Mya, Mytilus, Pecten, Unio, Venus) --[ummzADW links] Scaphopoda razor shells, tusk shells, tooth shells (Dentalium) --[ummzADW links]