Shell small- to medium-sized, 3 - 30 mm, usually 5 - 10 mm high, biconic, of mitriform shape. Sculpture rather smooth, with dominant spiral elements. Aperture narrow, with or without 1 - 3 columellar pleats, sometimes with denticles within. Siphonal canal short or indistinct. Anal sinus from indistinct to rather shallow indentation on weakly pronounced subsutural ramp. Protoconch multispiral or paucispiral, up to 4.5 smooth whorls. No operculum. Radula of hypodermic, marginal, relatively short, awl-shaped teeth with large swollen solid basal part. Distinct ligaments present, short. Tooth canal opening sub-terminally or laterally. At their tip, teeth can have a weak barb.

Mitromorphidae and Mitrolumninae were published the same year but Mitromorphidae (19 May 1904) has priority over Mitrolumninae (31 August 1904).