A sagittal section of a brain model shows the: cerebellum | the white matter of the cerebellum is called the arbor vitae | the cavity between the cerebellum and the brainstem is the  4th ventricle | the cerebral aqueduct connects the 4th and third ventricle, the cavity surrounding the intermediate mass of the thalamus |  pons |  the small bulges above and below the arrow tip are the superior and inferior colliculi of the corpora quadrigemina | the pineal body | midbrain |  corpus callossum |  fornix | the septum pellucidum is a membrane covering the entrance to the lateral ventricle | the hypothalamus lies beneath the thalamus | the  mammillary body |