Nassarius glans

The acorn dog whelk, Nassarius glans, is a marine gastropod mollusc belonging to the family Nassariidae, which includes the Nassa mud snails and dog whelks. Its shell, which ranges from 15 to 50 mm in length, is thin, smooth, and ovate-conical in shape. The base color is whitish, overlaid with spots of dark red, and a notably large, deeper red spot appears on the lower whorl.

On the convexity of this whorl, nine or ten parallel, transverse lines run in bright chestnut, brown, or blackish tones. The spire consists of eight whorls: the three lowest are smooth, while the upper five bear small, slightly curved longitudinal folds. The ovate aperture widens toward the base, which is deeply notched, and ends above in a small, dilated canal formed by a re-entering angle from the outer lip and a transverse tooth from the left lip.

The outer lip curves toward the top, thins from the middle to the base, and bears five conical, pointed teeth—the lowest being longest—with many fine transverse striae inside. The left lip forms a plate that laps over the shell body, creating a small projecting keel that ends below in a pointed, oblique tooth, from which a rounded fold spirals into the cavity. This species is found in the Red Sea, the Indian Ocean off Réunion, Mauritius, and the Mascarene Basin, as well as in the Indo-West Pacific.