Webster’s Revised Unabridged Dictionary · 1913
Pennatula
Pen·nat′u·la, n.; pl. L. Pennatulæ (#), E. Pennatulas (#). [NL., fr. L. penna a feather.] (Zoöl.) 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.