Fossil molluscs of uncertain position.
Green ormer (Haliotis tuberculata, Vetigastropoda). Picture: Florence Gully, Nature 22: Gastéropodes 1. |
Pillar snail (Cochlicopa lubrica, Stylommatophora). Picture: © Alexander Mrkvicka, Vienna (mrkvicka.at). |
Informal group "Lower Heterobranchia" (= Allogastropoda)
Informal group Opisthobranchia
Informal Group Pulmonata
Bouchet, P.; Rocroi, J.-P.; Frýda, J.; Hausdorf, B.; Ponder, W.; Valdés, Á.; Warén, A. (2005). "Classification and nomenclator of gastropod families". Malacologia 47 (1 - 2): 1 - 397.