vermetus

from The Century Dictionary.

• noun The typical genus of Vermetidæ, having the later whorls of the shell separated and crooked or tortuous.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) Any one of many species of marine gastropods belonging to Vermetus and allied genera, of the family Vermetidæ. Their shells are regularly spiral when young, but later in life the whorls become separate, and the shell is often irregularly bent and contorted like a worm tube.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun zoology Any of many species of marine gastropods belonging to Vermetus and allied genera, of the family Vermetidae.