Methacrylate-embedded E16 embryo (intermediate 1 horizontal)
Figure 52 is a slightly more ventral slice through the evaginating olfactory bulb. The same migratory streams are even more prominent than those in Figure 51. Note that the medial migratory stream (dashed-line arrows) is so dense that the outer edge of the NEP is obliterated; these may be the AOB output neurons, but a segregated AOB is not yet visible in the parenchyma of the olfactory bulb. The lateral mitral cell migratory stream is coming from a more posterior germinal source, skirting along and inside the lateral olfactory tract (where axons are accumulating) and entering what will probably become the plexiform layer in the main olfactory bulb. The olfactory nerve layer is thicker in this slice and is filled with fibers and migrating cells within the plane of the slice.