Shell to 16 mm long, sturdy, width about one-half length, with strongly impressed suture, tabulate shoulder; 13-20 strong, projecting, oblique axial ribs; interspaces of equal width; spiral cords overriding ribs, narrow on shoulder, broader on base where separated by deep incisions; columellar area with glossy shield, with two or three weak plications; lip with strong lirae, anteriormost tooth more strongly developed. Color variable; mottled gray brown or white, some with darker spiral banding or narrow spiral stripes. Protoconch conic, about three whorls, axial sculpture, with well-developed velar sinus.

Shell of about five whorls, last whorl two-thirds the length of the shell. Epidermis imperceptible; shell ornamented with rather strong sinuous ribs, which often invade the lower third of the whorl; there are fourteen to sixteen of these on the last whorl in well grown individuals, and they are crossed by rather strong, thread-like lines, between broad channels on the convexity of the whorls, which become narrower and groove-like on the anterior part of the last whorl. They are about seventeen in number, in average adult specimens, on the last whorl. Post labial pinch almost obsolete, quite so in some specimens. Colors very variable, pink, salmon color, livid bluish purple, brown and pure white, all plain, or variously marked with a network of white and brown lines, patches, dots.
Columellar callus less prominent than in the last; both have the entire aperture striated internally in some fine individuals, and often two or three tooth-like tubercles on the columella. Lon. 0,48 in. ; lat. 0,26 in.
This species is the most common beach shell found at Monterey. They are very uniform in size though so variable in color. They live under and about the stones at and near lowwater mark.

Dall (1871) described and illustrated this species in some detail, apparently to correct Carpenter's confusion of it with the much larger A columbiana. He then revisited the species in 1916, to differentiate four varieties (one of which was reticulata Dall), mostly by color. McLean & Kanner (2005) speculated that var. lineata Stearns may be a distinct species, based primarily on observations of a living specimen, in which the head and foot color differed from that of typical specimens of A. versicolor. The shells, other than color, are within the range of variation typically recognized in A versicolor, and specimens are found rarely, together with other color variants of that species. Accordingly, lineata is a mere form of A. versicolor. Dall's var. cymata has wavy brown axial lines on a white shell, and var. incisa is mottled, with "sharply cut regular sculpture" (Dall 1916: 27), personal experiences with columbellid species with variable shell color and pattern indicates that the body coloration of the animal often also varies, so body coloration is insufficient to assign such a variant species status. Similarly, the sculpture also tends to vary in Amphissa species; these should be investigated with molecular phylogenetic techniques in the future to confirm the nature and degree of variation within and between species.

Queen Charlotte Islands, British Columbia, to Rompiente Point, northern Baja California Sur. Mostly found intertidally but may occur in deeper water, especially in the southern part of the range. Southern California and Mexican specimens are sometimes intertidal but more frequently found deeper, to 30 m or more. Common.