Trochus

Trochus is a genus of medium-sized to large, top-shaped sea snails with an operculum and a pearly inside to their shells, marine gastropod molluscs in the family Trochidae, the top snails.

When the word "trochus" or "Trochus" is used in reference to fishing sea snails for commercial purposes, the usual species targeted is Tectus niloticus, which is valued for its nacre or mother of pearl layer, which was traditionally made into items such as pearl buttons and jewelry. Tectus niloticus is no longer classified as a Trochus species, and it is no longer classified in the family Trochidae; it is now placed in the family Tegulidae.

History

The name Trochus, according to P. Fischer was used for the first time by Guillaume Rondelet, in 1558, who assembled under this title a rather miscellaneous assortment of univalves. Linnaeus' genus Trochus is composed principally of true Trochidae, but it is now viewed as having contained species of several other very different families.

Lamarck still further restricted the group, by eliminating several genera; and in the 19th century the labors of Gray, H. Adams and A. Adams and others, contributed towards a more systematic arrangement of the family. Further revisions have narrowed down the number of species in this genus, and most names have become synonyms.