Shell large, up to 100 mm., elongate fusiform, with a tall spire and a long straight unnotched anterior canal. Protoconch small, of 1 1/2 to 2 whorls, smooth, the tip loosely coiled and inrolled, terminated by sigmoid brephic axials, a few in N. mirabilis, asmost a whorl of closely spaced axials in N. australis. Adult sculpture of prominent smooth spiral keels and cords, gemmate in the Miocene N. sucabumiana. Sinus deeply U-shaped, situated on the shoulder slope. Outer lip produced forward in a great swinging arc, which gives an appearance of considerable depth to the sinus. Operculum leaf-shaped, with a terminal nucleus. Colour pattern of reddish-brown axial flames (N. mirabilis and N. circumstricta) or orange-buff, with the primary spirals darker (N. australis). Range — Oligocene?: Burma. Miocene: Okinawa (type) and Java. Pliocene: Sumatra. Recent: IndoPacific; East Africa to Japan.