The Collaborative International Dictionary of English v.0.48:

Cirripedia \Cir`ri*pe"di*a\, n. pl. [NL., fr. L. cirrus curl +
   pes, pedis, foot.] (Zool.)
   An order of Crustacea including the barnacles. When adult,
   they have a calcareous shell composed of several pieces. From
   the opening of the shell the animal throws out a group of
   curved legs, looking like a delicate curl, whence the name of
   the group. See Anatifa.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Cirripedia
    n 1: barnacles [syn: Cirripedia, subclass Cirripedia]