1. Genus Columbella. Pl. [XII].

Animal. Imperfectly known; eyes placed much below the middle of the tentacula.

Shell. Thick, turbinated, with a short obtuse spire; aperture narrow, elongated and terminated by a very short canal, narrowed by an inflation at the inner side of the right edge, and by some folds on the columella; a very small horny operculum. Inhabits the Indian and American seas. Twenty species.

2. Genus Mitra. Pl. [XII].

Animal. Entirely unknown.

Shell. Turriculated, subfusiform and oval; spire always pointed at the summit; aperture small, triangular, widest anteriorly where it is strongly emarginated; external edge trenchant, nearly straight, always longer than the columella, which is formed by a very thin callosity, and marked with oblique parallel folds, the anterior of which are the shortest; no operculum. Inhabits the Chinese seas. Eighty species.

3. Genus Voluta. Pl. [XII].

Animal. Oval, involuted, provided with a very broad foot; head very distinct; tentacula rather short and triangular; eyes large, altogether sessile, and situated a little posteriorly; a thick trunk furnished with hooked teeth at its extremity; two pectiniform branchiæ.