Paired Masses of Grey Matter in the Brain
Puzzle 6 of Famous Horses Hard Pack
Question is: Paired Masses of Grey Matter in the Brain
and the answer is: THALAMUS
Word Meaning:
THALAMUS — (neuroanatomy) Either of two large, ovoid structures of grey matter within the forebrain that relay sensory impulses to the cerebral cortex.
Definitions from Wiktionary.