The Collaborative International Dictionary of English v.0.48:

Myzostomata \My`zo*stom"a*ta\, prop. n. pl. [NL., fr. Gr.
   my`zein to suck + sto`ma, -atos, mouth.] (Zool.)
   An order of curious parasitic worms found on crinoids. The
   body is short and disklike, with four pairs of suckers and
   five pairs of hook-bearing parapodia on the under side.
   [1913 Webster]