Holotype: Shell of medium to moderately large size for the genus; reddish brown, lighter colored on the pillar; length of aperture plus canal about 1/3 the length of the shell; suture deeply impressed, subsutural area concave, periphery shouldered. Protoconch of 3 smooth whorls, the tip small and immersed in the center; the first postnuclear whorl is carinate but nodulous with the emergent axial ribs; postnuclear whorls 8.5. Axial ribs 11 on early whorls, increasing to 15 on penultimate whorl, subdued in the subsutural area, extending diagonally across the body whorl, obsolete upon the back of the last whorl, except for the subsutural beading; lip edge preceded by an axial swelling 1/2 turn back; spiral sculpture of regularly spaced, deeply incised striae that evenly override the axial ribs, more deeply incised upon the pillar. Sinus deep, U-shaped, bordered on the inside by a parietal callus pad; lip edge not thickened, at an angle to the short, deeply notched anterior canal; inner lip slightly raised above the pillar. Height, 14.3, diameter, 4.8 mm.

Most of the paratypes are larger than the holotype (length to 20 mm), but in the larger specimens the last whorl has been injured and repaired. The holotype is the only uninjured specimen. It may be confused with no other species, the deeply incised spiral sculpture and brown color are characteristic, hence the name, meaning brown.

Type Locality: Off southern coast of Isla Santa Cruz, Galapagos Islands, Ecuador.