Webster’s Revised Unabridged Dictionary · 1913
Spirifer
Spi′ri·fer, n. [NL., fr. L. spira a coil + ferreto bear.] (Paleon.) Any one of numerous species of fossil brachipods of the genus Spirifer, or Delthyris, and allied genera, in which the long calcareous supports of the arms form a large spiral, or helix, on each side.