Figure 13. RF-I A. Neurons located on the esophagus of an adult male; typically two somata are present but in this case there is an additional, more faintly marked soma (arrow). Anterior is to the right. B. RF-I axons branch posterior to the esophagus to innervate the anterior stomach and outline the ventral diverticulum of an adult female. Anterior is to the right. Scattered FR-I enteroendocrine cells are seen in the posterior stomach (upper middle); Malpighian tubules join the gut at the left and part of dorsal diverticulum is visible to upper right of stomach.