Diencephalon is colored red in this medial view of a bisected canine brain. (Note: cingulate cortex has been remmoved above the corpus callosum of the telencephalon.)

The third ventricle (32) surrounds the interthalamic adhesion (33). The hypothalamus (optic chiasm, neurohyopophysis, and mamillary bodies) is visible ventrally. The large mass lateral to the interthalamic adhesion is thalamus. The group of small midline structures caudal to the interthalamic adhesion constitutes epithalamus.