Source : Webster's Revised Unabridged Dictionary (1913)

Pennatula \Pen*nat"u*la\, n.; pl. L. {Pennatul[ae]}, E.
   {Pennatulas}. [NL., fr. L. penna a feather.] (Zo["o]l.)
   Any one of numerous species of {Pennatula}, {Pteroides}, and
   allied genera of Alcyonaria, having a featherlike form; a
   sea-pen. The zooids are situated along one edge of the side
   branches.