Fig. 8. Cross section (15 µm) through the right Mauthner cell of Erpetoichthys calabaricus. The soma (S) of the Mauthner cell is centered in this photomicrograph. The lateral dendrite extends towards the right, where it bifurcates (arrows designate two branches) near the entry of the VIIIth cranial nerve. The axon (A) projects to the left toward the midline. Fibers that run parallel to the Mauthner axon project toward the soma and form a network of fibers around the initial segment of the axon to form the axon cap (delineated with a circle). Dorsal is up, and the open space above the Mauthner axon is the IVth ventricle. Scale bar, 40 µm.