Wikipedia
Pleurotomariidae
Pleurotomariidae, common name the "slit snails", is a family of large marine gastropods in the clade Vetigastropoda. This family is a very ancient lineage; there were numerous species in the geological past. The genus includes several hundred fossil forms, mostly Paleozoic. It is one of the oldest gastropod families, commencing in the Cambrian.
The superfamily is currently represented by a group of species that live only in deep water. This family has no subfamilies.
The first living specimens of a species in this family, Perotrochus quoyanus, were dredged in 1879 in deep water off the West Indies by the "Blake" expedition of William Healey Dall.1