The sculpture of this shell of Epitonium scalare is raised vertical ribs which are known as costae. Costae are a common feature in the shells of many species within the genus Epitonium, generally known as wentletraps (a word derived from the Dutch word for spiral staircase). This wentletrap species is particularly large, and the costae are exceptionally well developed; they are in fact the only structure that joins the whorls of the shell together.
This shell was greatly prized in Europe during the 17th and 18th centuries. The shell is still known as the "precious wentletrap", even though it no longer commands high prices from shell collectors.