The Collaborative International Dictionary of English v.0.48:

Decempedal \De*cem"pe*dal\ (d[-e]*s[e^]m"p[-e]*dal), a. [L.
   decem ten + E. pedal.]
   1. Ten feet in length.
      [1913 Webster]

   2. (Zool.) Having ten feet; decapodal. [R.] --Bailey.
      [1913 Webster]