Clanculus atricatena

Clanculus atricatena, common name the black-chained topshell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.

Description
The size of an adult shell varies between 15 mm and 20 mm. The umbilical shell has a broadly conical shape. The body whorl is rounded at its periphery. The umbilicus is wide and is bordered by a callus ridge with small nodules.

Distribution
This marine species is found off the coast of Transkei, South Africa.