The Collaborative International Dictionary of English v.0.48:

Quadrigeminal \Quad`ri*gem"i*nal\, Quadrigeminous
\Quad`ri*gem"i*nous\, a. [Quadri- + L. gemini twins.]
   Fourfold; having four similar parts, or two pairs of similar
   parts.
   [1913 Webster]

   Quadrigeminal bodies (Anat.), two pairs of lobes, or
      elevations, on the dorsal side of the midbrain of most
      mammals; the optic lobes. The anterior pair are called the
      nates, and the posterior the testes.
      [1913 Webster]