macrencephalic

from WordNet (r) 3.0 (2006)

macrencephalic
    adj 1: having a large brain case [syn: {macrencephalic},
           {macrencephalous}]

from The Collaborative International Dictionary of English v.0.48

Macrencephalic \Mac`ren*ce*phal"ic\, Macrencephalous
\Mac`ren*ceph"a*lous\, a. [Macro + encephalic, encephalous.]
   Of or pertaining to macrencephaly; having a large brain.
   [1913 Webster]