Figure 3. Semi-schematic dorsal views of the CNS of a fifth instar Phidippus clarus, based on reconstruction from serial sections. 1, Protocerebrum and eyes (shown in section). Areas containing cell bodies of retinal photoreceptors are shown in purple. The tiered retinae of the AME are shaded in green. The optic nerve (on) associated with each eye leads to a respective first neuropile, where sensory neurons synapse with interneurons. For the lateral eyes, these neuropiles are folded or convoluted, increasing the surface area available for synapses. Neuropile I of each AME includes two concentric lobes, shown at center. 2, Preoral rostral and postoral segmental ganglia. The rigid esophagus (not shown) is surrounded by two lateral esophageal nerves, and a dorsal recurrent nerve, all orginating from the preoral rostral ganglion. In addition to the primary segmental nerves, each prosomal segment is associated with a small dorsal nerve (dn), and a postero-dorsal nerve (pdn) that joins the dorsal nerve of the next, posterior segment. After Hill (1975, 2006).