Acrilla minor: As Acrilla thalia Bartsch, 1915:
Shell elongate-conic, light brown, with a narrow white band on the middle of each whorl. Nuclear whorls decollated. Postnuclear whorls decidedly rounded, separated by a strongly constricted suture, marked by well developed, very regular, almost vertical axial ribs, of which 18 occur upon the first of the remaining turns; 20 upon the second; 22 upon the third and fourth; 26 upon the fifth; 28 upon the sixth, and 34 upon the seventh and the penultimate turn. These ribs are about one third as wide as the spaces that separate them. Intercostal spaces marked by irregularly distributed, feebly incised, spiral striations. Periphery of the last whorl well rounded: marked by a poorly developed spiral cord. Base moderately rounded, marked by the continuations of the axial ribs, and feebly incised, spiral striations. Aperture oval; outer lip thin, showing the external markings within; inner lip decidedly curved and reflected; parietal wall glazed with a thin callus.
The type and another specimen. Cat. No. 186840, come from Port Alfred (Coll. No. 207). The type has nine whorls remaining and measures: length, 33 mm.; diameter, 8 mm. The other specimen which has lost the nuclear whorls, having the nine succeeding turns, measures: Length, 17 mm.; diameter, 4.3 mm.

This species ranges from the Arabian Sea to South Africa. While it occurs offshore, it has been found intertidally in South Africa. It reaches a maximum size of 34mm. It is light brown with a light band in the center of the whorls. There are approximately 12 whorls, with 24-34 sinuous costae per whorl. There are fine spiral threads between the costae and the intervals between the costae are approximately as wide as the costae. A basal cord is present which shows above the whorls. The outer lip is thin and the columella is white.
This species can be distinguished from A acuminata (Sowerby, 1844) which has much denser, less sinuous ribs and by the fact the basal ridge in the latter species does not show above the suture.