These precious wentletraps are a common Indo-West Pacific species, parasitizing on sea anemones on soft ocean bottoms. In the seventeenth and eighteenth centuries, however, they were valued above diamonds and rubies, and only a few connoisseurs–including Cosimo III de’Medici, Grand Duke of Tuscany, and Catherine the Great, empress of Russia–had the privilege of owning one. Wentletraps were so highly valued and were in such demand that they were counterfeited using rice flour past by Chinese artisans. The common name of this small and delicate shell derives from the German Wendeltreppe, “spiral staircase.”
This illustration comes from G.B. Sowerby, Thesaurus conchyliorum or Monographs of Genera of Shells, 1847-87.