A slender, transversely ribbed species, remarkable for the deep notch, widest within, and the deeply concave subsutural band.
Whorls ten, somewhat angular and shouldered; nucleus smooth, rather large, subglobular, of about one and a half whorls, as broad as the next whorl, the first unclear half-whorl is nearly covered by the next, the surface is glossy, marked on the lower half-whorl with rather indistinct spiral lines, which become more distinct on the next whorl. All the remaining whorls, except sometimes the last, are crossed by strongly marked, somewhat oblique, angular ribs, which are most elevated at the shoulder, below the strongly marked, concave, subsutural band; they do not extend on this band, and mostly fade out below, before reaching the suture; on the body-whorl the ribs are less distinct and sometimes absent, when present they extend only a little below the suture. The whole surface is covered with fine, wavy, spiral lines; fine, but rather conspicuous, lines of growth cover the surface, and recede strongly on the subsutural band.
Aperture small, ovate, rather narrow. Outer lip with a prominent, convex edge, which has a deep notch, situated a short distance below the suture. The notch is usually constricted or even nearly closed up at the edge of the lip, but is broadly rounded at its inner end; this gives it a button-hole like appearance. In some specimens it is but little constricted. Canal short, broad, slightly everted.
Color, brown of various tints; often deep brown, with one or two spiral bands of yellowish brown, and with streaks of light brown; or the ribs may be pale yellowish brown; aperture brown within; columella whitish in front. Animal not seen. Operculum not observed.
Length of the largest specimen, 19.5mm; greatest diameter, 6mm; length of body-whorl and canal, 10mm; of aperture, 6mm; breadth of aperture, 2.5mm.
Off Martha's Vineyard, stations 1085, 1036, 1038, 1039, in 94 to 140 fathoms, 1881. Off Delaware Bay, station 1046, 104 fathoms, dredged by Lieut. Z. L. Tanner, Oct. 10, 1881.