The Collaborative International Dictionary of English v.0.48:

Aplacophora \Ap`la*coph"o*ra\, n. pl. [NL., fr. Gr. 'a priv. + ?
   a flat cake + fe`rein to bear.] (Zool.)
   A division of Amphineura in which the body is naked or
   covered with slender spines or set[ae], but is without shelly
   plates.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Aplacophora
    n 1: an order of Amphineura [syn: Solenogastres, order
         Solenogastres, Aplacophora, order Aplacophora]