Shell 3-5 mm, with about four teleoconch whorls; biconic, suture shallow; semi- translucent, usually smooth except for spiral striations on canal, but some specimens with broad, low axials, mostly on body whorl. With chevron pattern of thin, brown lines on off-white background (not irregular pattern of wavy longitudinal lines), usually with spiral row of white blocks below suture; labial edge not denticulate; columella smooth, without much callus; protoconch broadly conical, brown with paler flush, 1.75-2 whorls, no velar sinus.

Shell minute, fusiform, smooth, with five gently rounded, non-carinated whorls. Color generally orange yellow, semitranslucent, and without markings, but occasionally darker, passing into dark brown, or with close zigzag brown lines on the yellow ground. Columella slightly arcuated, outer lip slightly sinuated, hardly striate inside. No callus on the columella. Nucleus subglobular, rounded above, swollen as large or larger than the first whorl in most specimens. Lon. 0,18 inch., lat. 0,08 inch.
Habitat, Monterey, in the sand along the wave marks, dead ; Dall, seven specimens. Stones at low water, living; Stearns and Canfield. "
This little species is about one-half the size of the preceding, yet has as many whorls. The latter are rounded though not inflated, not flattened as in the last. The nucleus also differs. A. tuberosa is conoid, this is regularly fusiform. I have not seen any specimens of tuberosa, with exactly similar zigzag lines, such as three of my specimens of aurantiaca exhibit.

Axial ridges are rare in species of Mitrella, but are also present in M. baccata Gaskoin, 1852, from Mexico to Central America and M. caulerpae Keen, 1971, from Baja California. This species was described in Astyris, but those tend to be cold-water taxa with thin, white shells.

Vancouver Island, British Columbia, to Cedros Island, Baja California. Intertidal to 20 m; uncommon but most often found in low intertidal zone among rocks and algae.