Chapter 14 - Section 14.1 - Overview of the Brain - Before You Go On - Page 510: 4

The neural tube splits into the forebrain, the midbrain, and the hindbrain. The forebrain divides into the telencephalon and the diencephalon. The hindbrain divides into the metencephalon and the myelencephalon. Therefore, by the fifth week, the neural tube splits into the telencephalon, the diencephalon, the mesencephalon (midbrain), the metencephalon, and the myelencephalon.

The neural tube splits into the forebrain, the midbrain, and the hindbrain. The forebrain further splits into the telencephalon (which will turn into the cerebral hemispheres) and the diencephalon (which will turn into the optic vesicles that become the retinas). The midbrain doesn’t split and keeps the name mesencephalon. The hindbrain splits into the metencephalon and the myelencephalon. The metencephalon differentiates into the pons and the cerebellum. The myelencephalon differentiates into the medulla oblongata.