Source : Webster's Revised Unabridged Dictionary (1913)

Spiralozooid \Spi*ra`lo*zo"oid\, n. [Spiral + zooid. So called
   because they often have a spiral form when contracted.]
   (Zo["o]l.)
   One of the special defensive zooids of certain hydroids. They
   have the form of long, slender tentacles, and bear lasso
   cells.