Methacrylate-embedded E18 embryo (intermediate horizontal)
Figure 85 is a more ventral slice through the main olfactory bulb in the same specimen as Figure 84. The lateral migratory stream of mitral cells is prominent; spindle-shaped cells exit the lateral olfactory tract to migrate into the internal plexiform layer where they peel off to join clumps of settling mitral cells. This slice clearly shows the layering in the main olfactory bulb—there are clumps of larger mitral cells sandwiched between the cell-sparse external plexiform layer and the internal plexiform layer. The presumptive anterior olfactory nucleus and the primary olfactory cortex are farther back; the anterior limb of the anterior commissure is prominent and some cells may be migrating forward along its fibers to the anterior olfactory nucleus (dashed-line arrow).