Seguenziidae Verrill, 1884

(Figures 1–3)

Description. Shell trochiform, turbiniform, or planispiral, 2–10 mm, umbilicus narrow or anomphalous, interior nacreous except Adeuomphalus . Peritreme incomplete (entire in Adeuomphalus), aperture lacking a slit or foramen, but some genera with up to three labral sinuses. Operculum corneous, paucispiral.

Remarks. In the northeast Pacific, all sequenziid species occur on outer continental shelves at deep to abyssal depths, where they are detritivores (Quinn, 1983b). Specimens are seldom collected and the family is poorly known.