The Collaborative International Dictionary of English v.0.48:

Procephalic \Pro`ce*phal"ic\, a. [Pref. pro- + cephalic.]
   (Zool.)
   Pertaining to, or forming, the front of the head.
   [1913 Webster]

   Procephalic lobe (Zool.), that part of the head of an
      invertebrate animal which is in front of the mouth.
      [1913 Webster]