Spur-shell

Spur´-shell`

    (spûr´shĕl`)
n.1.(Zool.) Any one of several species of handsome marine gastropod shells of the genus Trochus, or Imperator. The shell is conical, with the margin toothed somewhat like the rowel of a spur.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.