Sigmurethra is a taxonomic category of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This is an informal group which includes most land snails and slugs. The two strong synapomorphies of Sigmurethra are a long pedal gland placed beneath a membrane and retractile tentacles. Several families in this group contain species of snails and slugs that create love darts. Sigmurethra are known from the Cretaceous to the Recent periods.