Drillia tholosDrillia tholos is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.DescriptionDead Drillia tholos often form shallow marine sediments. The shells attain lengths of 5 mm, their diameter 2 mm, dextrally coiled. It is a rare species and only found in certain regions across the globe.DistributionThis species occurs in the demersal zone off East London, South Africa.