parent_taxon xanthonychidae
___MASK44___ is a taxonomic superfamily of air - breathing land snails , terrestrial pulmonate gastropod mollusks in the clade ___MASK78___ . Snail is a common name that is applied most often to land snails , terrestrial pulmonate gastropod molluscs . However , the common name " snail " is also applied to most of the members of the molluscan class ___MASK99___ that have a coiled shell that is large enough for the animal to retract completely into . When the word " snail " is used in this most general sense , it includes not just land snails but also thousands of species of sea snails and freshwater snails . Occasionally a few other molluscs that are not actually gastropods , such as the Monoplacophora , which superficially resemble small limpets , may also informally be referred to as " snails ". Xanthonychidae is a family of air - breathing land snails , terrestrial pulmonate gastropod mollusks in the superfamily ___MASK44___ . This family is within the clade Eupulmonata ( according to the taxonomy of the ___MASK99___ by Bouchet & Rocroi , 2005 ) . ___MASK78___ is a taxon of air - breathing land snails and slugs , terrestrial pulmonate gastropod molluscs . This taxon is considered to be a clade . It used to be regarded as an infraorder ( also sometimes was considered to be an order ). This taxon includes the majority of land snails and slugs .