Tricolia perforata (Philippi, 1848) Eulithidium perforata is a species of small sea snail with calcareous opercula, a marine gastropod mollusk in the family Phasianellidae, the pheasant snails.

It is characterized by extremely minute wrinkling over the whole surface, only discernible under the microscope when quite fresh.

The umbilicus is very large when young, and sharply keeled; when adult it is often nearly filled up by the callous lip.

The suture and the periphery are ornamented with large maculations of white and purple.

The operculum is radiately wrinkled over a large part of the outer surface.