FAMILY VALENCINIIDAE HUBRECHT, 1879

Poliaidae [sic] Hubrecht, 1879: 208 [invalid in accordance with Article 39 of the Code (ICZN, 1999)].

Valenciniaidae [sic] Hubrecht, 1879: 208.

Eupoliaidae [sic] Hubrecht, 1887: 10.

Baseodiscidae Bürger, 1904: 79 .

Taeniosomidae [sic] Sumner et al., 1913: 590.

Oxypolellinae Chernyshev, 1995: 14 (synonymous when placed at the rank of family).

Diagnosis: Pilidiophorans without horizontal lateral cephalic slits; transverse cephalic furrows present or absent; proboscis without pseudocnidae, mostly lacking muscle crosses; one or no frontal organ (as opposed to three frontal organs in Lineidae).