Brown slug or Arion distinctus

''Arion distinctus'' is a species of air-breathing land slug in the family Arionidae, sometimes known as the roundback slugs. It is a terrestrial pulmonate gastropod mollusc. Several vernacular names exist, but it is unclear if they are much in use: brown soil slug, common garden slug, darkface arion, Mabille's orange-soled slug, April slug.