Methacrylate-embedded E17 embryo (ventral horizontal)

Figure 69.  This ventral horizontal slice from the same specimen in Figures 67 and 68 clearly shows two different streams of migrating mitral cells.  Both streams come toward the bulb from diffuse streaks of spindle-shaped cells near the pia in the basal telencephalon.  Once the stream reaches the posterior bulb, many cells make a sharp medial curve into the medial external plexiform layer, and peel off to settle in the mitral cell layer (dashed-line curved arrows).  At the same time, other mitral cells (possibly coming in from a more dorsolateral germinal source) migrate from lateral to medial in the external plexiform layer and join the mitral cell layer (solid-line curved arrows).