Protoconch, blunt, of three convex whorls, the first smooth, the second and third with distant, valid, axial, sigmoid, round cords. Spire whorls with close spirals, rounded, wider than the interspaces, five in the penultimate whorl, the lowest two more prominent throughout, the upper three diminishing in number towards the apex where there is but one; periphery roundly angular; base nearly flat with six spirals; axial, obsolete, round costae, nearly as wide as the interspaces, fourteen in the penultimate whorl; mouth roundly rhomboid; outer lip slightly expanded, sharp, crenulated; inner lip erect and free; canal short, nearly closed at front of point of contact of inner and outer lip, reflected; collumella curved and forming an obtuse angle at the canal. Shell colour of holotype white. Holotype height 8 mm., diameter 2,9 mm., Cape Borda, S. Aust., 55 fathoms (D. 13435). Distribution : 81 miles west of Eucla, 4 fathoms; Gulf St. Vincent, ? depth, seven specimens larger and more solid than the type, four are uniformly brown, another has the protoconch white and the rest of the shell brown, two are nearly white; 45 fathoms east of north of the Neptune Islands; Beachport, 100-150 fathoms, one specimen brown; Gulf St. Vincent, 10 fathoms; 50 miles west of Eucla, W. Aust., 80 fathoms.
This species differs from A. serotinum in having valid spirals of obsolete axials. In A. serotinum the axials are more prominent than the spirals.