See text Gymnomorpha The Systellommatophora (synonym Gymnomorpha) is a clade of primitive, air-breathing slugs, according to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005).

Slugs in the superfamily Onchidioidea are primarily marine (except for five land-dwelling or freshwater species),[2] whereas slugs in the superfamily Veronicelloidea are primarily terrestrial.

[2][3] These slugs are distinguished by the location of the anus at the rear of the body.

[7] According to the previous taxonomy of the Gastropoda (Ponder & Lindberg, 1997) Systellommatophora was considered to be a suborder or an order.

[8] The following two superfamilies and families have been recognized in the taxonomy of Bouchet & Rocroi (2005):