Source : Webster's Revised Unabridged Dictionary (1913)

Acanthocephala \A*can`tho*ceph"a*la\, n. pl. [NL., from Gr. ? a
   spine, thorn + ? head.] (Zo["o]l.)
   A group of intestinal worms, having the proboscis armed with
   recurved spines.

Source : WordNet®

Acanthocephala
     n : phylum or class of elongated wormlike parasites that live in
         the intestines of vertebrates: spiny-headed worms [syn: {phylum
         Acanthocephala}]