Dark to reddish-brown with lighter bands just below suture and on base. Apex sharp, adult whorls flattened. Axial ribs relatively strong and straight, 14-16 per whorl, evanescing on the base of the last whorl, but ending below the suture in a row of small nodules (or a weak spiral ridge). Base bears strong, rounded spiral ridges. Inside edge of outer lip with a row of small denticles, becoming even finer posteriorly, where there is a shallow sinus. Length ca 5 mm. Distribution and habitat: Indo-Pacific to northern Transkei, living in sheltered bays, usually on mudflats where it forms small colonies under stones or on shells such as Pinna.
Note: Differs from Zafra selasphora in its larger size and largely uniform brown colour (in life often stained with black oxides), and lack of a silky or slightly iridescent sheen. Common in Durban Bay, rare along the open coast. Types: Lectotype of ColumbeUa atrata, USNM 2026, paralectotypes in USNM, MCZH and Redpath Mus.; type
loc. Hong Kong harbour, China.