A whole mount of the brain (A) and coronal section through the rhombencephalon (B) of a human embryo. Abbreviations: A, Augenblase, eye; Br, Brueckenkruemmung, pons; Gb, Gehorblase, ear; H, Hemisphaerenhirn, telencephalon; Hh, Hinterhirn, pons; J, Isthmus; M, Mittelhirn, midbrain; N, Nachhirn, medulla oblongata; NK, Nachhirnkruemmung, bridge of spinal cord; Rf, Rautenfeld, rhombomeric choroid plexus; Z, Zwischenhirn, diencephalon; rl = rhombic lip; G.X. = ganglion of the vagus nerve. Taken from His (1897).