Ptychobela baynhami

The length of the shell attains 29 mm, its diameter 9 mm. Like Ptychobela suturalis (Gray, 1838), this fusiform, turreted species has a raised fillet at the suture. But it may be distinguished by its shorter body whorl, its more pronounced ribs, and the difference of colour. The shell contains 12 whorls; the first two are smooth and globose. The subsequent whorls are concave above the middle and convex below. The ribs (in the penultimate whorl 9–10) become obsolete a little above the middle of the whorls where the concavity commences, and, being traversed by a distinct tenuous white spiral thread, have a somewhat angulated appearance. The aperture measures 2/5th of the total length. The inner part of the aperture is livid. The columella is slightly arcuate and has a minute callus.