Shells very small (height from 1 to 2 mm); H/D ratio ranging from 1 to 2. Sculpture very regularly clathrate, with numerous evenly-spaced spiral cords (eight to 13 on body whorl), similar in appearance on base and spire; spiral cords intersected by numerous axial lamellae (25 to 45 on body whorl). Intersection of axial and spiral sculpture forming slightly or very slightly prominent nodes. In addition to this primary sculpture, microsculpture of spiral lamellae distinctly visible between ribs and cords. Stronger spiral cord or keel may mark periphery of body whorl. The more developed this peripheral keel, the flatter the spire whorls. Suture narrow but rather deep. Narrow but deep umbilicus always present, lined by strong prominent rib merging abruptly with base of peristome. Aperture rather broad; peristome consisting of numerous concentric rings stacked in flat disk projecting strongly outwardly. In lateral view, disc lying obliquely, parallel to one side of spire, so that the stouter the shell, the more oblique the apertural rim. Spiral sculpture extending onto body whorl to back and side of outer lip. Protoconch of all species except one planktotrophic, with 2.5 whorls; seven spiral cords, often in pairs, plus additional small pustules forming more or less regular spiral alignments. Sculpture of teleoconch initially with a single spiral cord, continuous with main spiral cord of larval shell.