Palaeos		Pulmonata
Mollusca		Pulmonata

Pulmonata

GASTROPODA  
|--Caenogastropoda
`--Heterobranchia
   |--Opisthobranchia
   |
   `--PULMONATA
      |==Basommatophora
      `--+--Stylommatophora
         `--+--Systellommatophora 
            `==Acteophila  

Mesodon altivagus (Pilsbry, 1900), (Heterobranchia: Pulmonata: Eupulmonata: Stylommatophora: Sigmurethra: Helicoidea: Polygyridae) Clingmans Dome, Tennessee. Photo by John Slapcinsky Creative Commons Non-Commercial Attribution via Encylopedia of Life.

The Pulmonata or land snails, slugs, pond snails, and air-breathing mangrove snails are a huge group a gastropods characterised most distinctively by advanced Heterobranchia morphology and the opossesison of a lung rather than gills, which gives them the ability to breathe air. They are also united by a number of other advanced gastropod features such as a single auricle and kidney, a uncrossed or loop-like nervous system and hermophroditism. Previously considered a subclass, it now seems that the pulmonates, are a polyphyletic assemblage, with several lineages of Euthyneuran gastropods independently aquiring air-breathing capacity. Molecular phylogeny and other advances have also improved our understanding of this important assemblage of molluscs. Although the pages in this unit are therefore somewhat dated, they have been retained as is, pending a more comprehensive study and revision. MAK120621