Teleoconch of about 7 very slightly convex whorls, separated from each other by a narrow and deep suture. The sculpture, typical of the genus, is made up of numerous narrow axial folds crossed by conspicuous spiral ribs. The axials are also markedly present on the large labial varix. – Above and below: 12m deep, Samandağ, Hatay Province, SE. Turkey. 5,8mm.

Compared to the other members of the genus in Mediterranean, ambigua has the less convex whorls and the more numerous and weakest axials; also, the spiral sculpture does not appear on the labrum. The species is planktotrophic, with a protoconch of 2,5 whorls. The transition to the teleoconch (not pictured here) is sinusigeral.

« Shell oblong-acuminate, the outlines of the spire convex; solid, white. Sculpture of many small straight, crowded, rounded, low longitudinal riblets, the intervals transversely striate. The apex is wanting, about 6 whorls remaining. These are slightly convex and separated by a shallow, linear suture. The last whorl is swollen into a wide rounded varix behind the outer lip, the fine riblets of the rest of the surface being developed also upon it. The aperture is semioval, the thick outer lip a little advanced below; columellar margin moderately concave, truncate below by the shallow, roimded basal channel. » – H. A. Pilsbry: “New Japanese marine Mollusca: Gastropoda”, Proceedings of the Academy of Natural Sciences of Philadelphia vol. LVI, Philadelphia 1904, p.27.