Animal. Entirely unknown.

Shell. Thin, shining, subcylindrical, involute, pointed posteriorly, truncated anteriorly; aperture longitudinal, triangular; edges entire; columella truncated, and prolonged beyond the aperture. Inhabits the Indian Ocean. Three living species and two fossil.

4. Genus Ancillaria. Pl. [XII].

Animal. Unknown.

Shell. Smooth, oval, oblong posteriorly, widened and truncated anteriorly; aperture oval, somewhat elongated, angular posteriorly; a wide but not deep slope anteriorly; columella covered anteriorly with an oblique callous band; right lip obtuse, Inhabits the Australian seas. Four living species, and five fossil.

5. Genus Oliva. Pl. [XII].

Animal. Oval, involute, mouth somewhat thin at its edges, prolonged to the two angles of the branchial aperture in a tentacular band, and, anteriorly, by a long branchial tube; foot very large, oval, subauriculated, with a transverse cleft anteriorly; head small, with a labial proboscis.

Shell. Thick, solid, smooth, oval, elongated, subcylindrical; the whorls of the spire very small, and separated by a canal; aperture long and narrow, the columellar edge dilated anteriorly by a band striated obliquely in all its length. Found in the Australian and Equatorial seas. Only one species has been found in America. Sixty-three species. Six fossil.