3. The pons ([p. 347]).
4. The mesencephalon ([p. 351], and [Figs. 141] and [142]). Study it first in a preparation. Then study the floor on your own specimen; origin of third nerves.
5. The diencephalon ([Figs. 141] and [142]). Study the roof and thalami and the pineal body on a preparation and on a longitudinal section; the floor on your specimen.
6. The telencephalon ([p. 357]). (Note that only one side of this is to be dissected.)
a. Study it externally; sulci and gyri ([Figs. 145] and [146]).
b. Examine a preparation showing the corpus callosum ([Fig. 147]). Then slice away with a very sharp scalpel the top of one hemisphere nearly to the corpus callosum (see the preparation). Expose the corpus callosum on this side to its cranial and caudal borders, by tearing away the brain-substance at its side and above it.
c. Raise the corpus callosum at the side and remove it, thus exposing the lateral ventricle in which note the septum pellucidum and fornix, the corpus striatum, and choroid plexus of the lateral ventricle ([Fig. 148]). (These are to be exposed on one side only, the other being left intact.)
d. Expose the anterior and inferior horns of the ventricle and find the hippocampus, the fimbria, caudal part of the fornix, the foramen of Monroe, the anterior commissure. See all these also on a preparation ([Fig. 148]).
e. Remove the occipital and parietal portions of the cerebrum, on the side already dissected, so as to expose the roof of the third ventricle and the midbrain in your specimen, and note the pineal body, choroid plexus of third ventricle, and structures on the roof of the midbrain ([Fig. 141]).
f. Remove the choroid plexus or roof of the third ventricle and study again the thalami ([Fig. 141]).