Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Tegula pulligo, common name the dusky tegula, is a species of medium-sized sea snail with gills and an operculum, a marine gastropod mollusc in the family Turbinidae. This is an Eastern Pacific Ocean species. Turbinidae, the turban snails, are a family of small to large marine gastropods. Turbinidae have a strong, thick calcareous operculum readily distinguishing them from the somewhat similar Trochidae or top snails, which have a corneous operculum. This strong operculum serves as a passive defensive structure against predators that try to enter by way of the aperture or that would break the shell at the outer lip.