Pulmonata
Pulmonata, or "pulmonates", is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includes many land and freshwater families, and several marine families. The taxon Pulmonata as traditionally defined was found to be polyphyletic in a molecular study per Jörger "et al.", dating from 2010. Pulmonata are known from the Carboniferous Period to the present. Pulmonates have a single atrium and kidney, and a concentrated, symmetrical, nervous system. The mantle cavity  is located on the right side of the body, and lacks gills, instead being converted into a vascularised lung. Most species have a shell, but no operculum, although the group does also include several shell-less slugs. Pulmonates are hermaphroditic, and some groups possess love darts. Linnean taxonomy. The taxonomy of this group according to the taxonomy of the Gastropoda (Ponder & Lindberg, 1997) was as follows: Order Pulmonata Cuvier in Blainville, 1814 - pulmonates 2005 taxonomy. The taxonomy of this group according to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) was as follows: Informal Group Pulmonata. Contains the informal group  Basommatophora and the clade Eupulmonata Informal Group Basommatophora. Contains the clade Hygrophila Clade Eupulmonata. Contains the clades Systellommatophora and Stylommatophora Clade Stylommatophora. Contains the subclades Elasmognatha, Orthurethra and the informal group Sigmurethra other Sigmurethra. Two superfamilies belongs to clade Sigmurethra, but they are not in the limacoid clade. 2010 taxonomy. Jörger "et al." (2010) analyzed major groups within the Heterobranchia using genetic data and found that Pulmonata as traditionally defined was polyphyletic, for instance some pulmonates were more closely related to Sacoglossa and Acochlidia. They proposed the more inclusive taxon Panpulmonata to unite the clades Siphonarioidea, Sacoglossa, Glacidorboidea, Pyramidelloidea, Amphiboloidea , Hygrophila, Acochlidia and Eupulmonata.