Shell small, unusually solid, elongate-ovate, with 4 protoconch and 3 teleoconch whorls. Spire rather high (ratio spire height to total shell height 0.38); protoconch smooth large dome-shaped with a central nucleus; sutures well defined but not deeply indented. Teleoconch whorls rounded with only weakly developed shoulders; first teleoconch whorl with very weak axial folds, penultimate whorl with 11 low axial folds which tend to form weak nodules at the shoulder, body whorl with 5 weak axial folds at the shoulder on the ventral and left sides but lacking these on the dorsal and right sides; teleoconch whorls smooth except for fine growth lines and minute wavy spiral striae. Aperture narrow, elongate-elliptical; anterior canal moderately broad and deep, oblique, U-shaped; anterior fasciole short and low but well developed; columella calloused, with 4 strong, oblique plaits, of which the first and second are stout rounded and the third and last are rather more angulate and narrow; a prominent spiral cord on the parietal wall may represent a fifth columellar plait. Protoconch cream, teleoconch pale orange with numerous tent-shaped pinkish white markings of variing size, with a few thin short wispy orange-brown lines on the sutural ramp of the body whorl arising from the sutures, columella tawny, especially at the anterior end, columellar plaits white, deep interior pinkish white becoming pale orange toward the lip and tawny toward the anterior end. Holotype Height: 3.72 cm; Width: 1.43 cm.

At first glance the type specimens might be taken for juvenile V. hargreavesi (Angas, 1872) or V. coniformis (Cox, 1871). The known geographic range of V. hargreavesi is from Wedge Island to the Dampier Archipelago, Western Australia and the type locality of the new species lies within this range. V. coniformis is found further north (Nickol Bay to Broome). Both species are much larger than V. capricorneus, minimum recorded shell height of adults being 6 cm in V. coniformis and 7.5 cm in V. hargreavesi. The protoconch is much smaller in V. capricorneus although the number of protoconch whorls is about 4 in all three species. A calcarella is usually prominent in V. hargreavesi, very small in V. coniformis, and absent in V. capricorneus. The protoconch is smooth in V. capricorneus, smooth or axially Urate in V. hargreavesi, and axially lirate in V. coniformis. The teleoconch whorls are weakly axially lirate and spirally striate in V. capricorneus, smooth or axially lirate in V. hargreavesi, and very finely striate both axially and spirally in V. coniformis.
Apart from these differences the shell characters of the new species match those of the Recent species of Volutoconus quite well, but because of the lack of a calcarella its assignment to that genus must remain provisional. Lack of a calcarella in the two similarly small Miocene species V. ralphi and V. limbata lends support to the placement of V. capricorneus in Volutoconus, although the generic position of all three species may well be questioned. Study of the soft parts of V. capricorneus may do much to resolve this matter when living specimens are discovered.

Northwest Austrralia.
The specific name of this new species alludes to the proximity of the type locality to the Tropic of Capricorn.