Source : Webster's Revised Unabridged Dictionary (1913)

Ambulacral \Am`bu*la"cral\, a. (Zo["o]l.)
   Of or pertaining to ambulacra; avenuelike; as, the ambulacral
   ossicles, plates, spines, and suckers of echinoderms.

Source : WordNet®

ambulacral
     adj : pertaining to the ambulacra of radial echinoderms