01 n. Any one of numerous species of fossil brachipods of the genus Spirifer, or Delthyris, and allied genera, in which the long calcareous suppo…
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1.
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.(Paleon.)