"Diagnosis: Shell glossy, lacking periostracum, narrowly fusiform, with high to very high last whorl and narrow aperture tapering adapically. Siphonal canal absent, anterior end of shell distinctly notched. Anterior shell end with poorly defined anterior band, very slightly raised above the shell cloak. Plication plate limited to columella, with spiral plicae (Belloliva) or not (Olivellopsis). Primary spire callus absent. Narrow filament channel present, opened on all spire whorls. Foot with well-developed crescent-shaped propodium, subdivided by a longitudinal cleft on the dorsal side, and parapodia partially embracing the shell. Operculum present. Radula with three teeth per transverse row. Central tooth with three large, closely spaced cusps and, in Belloliva, with distinct small cusps adjoining the major lateral cusps (Fig. 11B), that are indistinct or absent in Olivellopsis (Fig. 11C). Mantle with mantle filament, a small anterior mantle lobe, and without anterior mantle tentacle. Head formed by dorso-ventrally compressed flaps with or without eyes, at least in Olivellopsis on very short and narrow tentacle.".