Shell small, 25 mm. (1 inch) in height, fusiform, with tall spire and moderately long, straight anterior canal. Spire slightly greater than height of aperture plus canal. Whorls probably about 10; the apex is badly eroded in the figured holotype. Outline of whorls steeply descending over a broad shallowly concave shoulder area, to a low-set heavy, rounded peripheral keel, which is studded with large blunt tubercles, about 8-9 per whorl. Spiral sculpture consisting of very faint threads on the shoulder slope, a closely spaced series of slightly stronger threads in the interstices of the peripheral nodes and then extending over the base, but becoming obsolete towards the end of the anterior canal. Sinus deep, broadly rounded at its apex and occupying the whole of the shoulder area, produced horizontally forward at its lower extremity and then confluent with the arcuately projected swing of the thin outer lip. Colour white, covered by a light olivaceous periostracum.
Height 25.0 mm width 9.0 mm

The low-set peripheral nodulose keel in this species suggests Makiyamaia, but in that genus the sinus is much narrower at its apex, not broadly arcuate, occupying the whole of the shoulder slope, as in arcana. The operculum of arcana is unfortunately unknown. Examples of an allied species from the John Murray Expedition, Gulf of Aden in 2000 metres are similar but have a shorter spire and more numerous peripheral nodules.

Off Andaman Islands, 185 fathoms (type locality) and India, off Travancore coast, 360 fathoms.