The diencephalon is connected above and in front with the cerebral hemispheres; behind with the mid-brain. Its upper surface is concealed by the corpus callosum, and is covered by a fold of pia mater, named the tela chorioidea of the third ventricle; inferiorly it reaches to the base of the brain.
- corpora geniculata
- epithalamus, consisting of the trigonum habenulæ, the pineal body, and the posterior commissure
- posterior part of the third ventricle