quadrigeminous

from The Century Dictionary.

• Consisting of four similar parts; having four parts, as one and the same thing; fourfold; quadrigeminal.
• In anatomy and zoology, specifically, pertaining to the optic lobes or corpora quadrigemina of any mammal, known in human anatomy as the nates and testes, which appear as two pairs of lobes or tubercles on the morphologically superior surface of the midbrain or mesencephalon, close to the pineal gland, behind the third ventricle, over the aqueduct of Sylvius. See corpus and quadrigemina.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Archaic form of quadrigeminal.