Shell rather small (up to 4.1 mm, N = 18), broadly to very broadly conical, stout. Protoconch of non-planktotrophic larval type ; glossy, trans¬parent, of 1 whorl; transition to teleoconch abruptly with a weakly sinuous, non-thickened margin. Teleoconch of 4 1/2 to 5 1/2 whorls; adapical spire whorls flat-sided, moderately angulate above sutures ; abapical spire whorls convex, not angulate ; sutures strongly undulated, moderately impressed on adapical spire whorls, weakly impressed on abapical whorls ; last whorl moderately convex, not contracted near shell base. Adapical spire whorls with fine, moderately distantly spaced axial ribs, crossed by moderately distantly spaced spiral ribs, forming weak, rounded nodules where intersecting axial ribs ; subsequent whorls with prominent, rounded, distantly spaced axial ribs, intersected by slightly narrower, more closely spaced, rather sharp spiral ribs; the latter forming rather prominent nodules where intersecting axial ribs ; the latter continuous to the peristome on last whorl. Microsculpture of typical axial threads in interspaces between spiral ribs. Aperture: ovate; inner lip thin, moderately wide ; anterior channel very narrow, very deep and short; posterior channel short and bent to the right; outer lip thin internally, apart from a more or less prominent swelling near transition to the posterior channel and apart from some rather elongate ridges, the latter corresponding to the spiral ribs on the external varix ; outer lip externally with a thick and narrow varix, the latter bearing prominent, distantly spaced, sharp to rounded spiral ribs; outer lip with a moderately deep, posteriorly located notch ; outer lip weakly opisthocline in profile. Shell colour: white. Variation — Apart from the shell size, no marked differences between specimens of different localities were observed.

Affinities and differences — Stosicia abnormis strongly resembles S. mirabilis (WEINKAUFF, 1881) S. abnormis superficially resembles S. hedleyi (TATE, 1899), but differs essentially in having a protoconch of non-planktotrophic larval type and in having a more broadly conical shell; furthermore, S. hedleyi lacks the posterior channel, which is slightly bent to the right in specimens of S. abnormis.

Stosicia abnormis appears to be widely distributed in the Indo-Pacific, ranging from Reunion to the Samoa Islands; the absence of the species in some intervening areas — especially in the Indian Ocean- is probably due to the rarity of this species or to poor collecting in those areas