About Calliostoma tricolor Gabb, 1865
Calliostoma tricolor Gabb, 1865 has a rather solid, conical shell that typically has around 7 obtusely bi-angular shouldered whorls. The upper section of each whorl ranges from slightly concave to flat, and the superior angle is prominent on the spire whorls. Early whorls feature minutely beaded threads, which become smoother, developing into fine smooth spiral ribs on later whorls. The height of the full shell ranges from 18 mm to 25 mm. The apex is acute and very small. The shell surface forms a finely, densely granulated pattern from the decussation of numerous spiral striae with close, regular, impressed growth lines. The base of the shell is slightly convex, encircled by numerous unequal lirae. The oblique aperture is subrhomboidal. The arcuate columella is not truncate at its base; its edge is pearly white, backed by a curved purple streak that is surrounded by a band of bright light yellow. The base shell color is yellowish brown or olive-ashen, with a pattern of three or four spaced spiral rings made of alternating brown and white bars on the upper portion of the shell. The base of the shell holds six similarly marked rings. The upper shell is often obscurely clouded with dark brown or olive, and frequently has white spots between the dark patches. This species occurs subtidally, ranging from San Francisco, California to San Martin Island, northern Baja California. It is found offshore at depths between 16 and 70 meters.
