Figure 3

Central and stomatogastric nervous system of the head region of Axiothella rubrocincta. Anterior faces upwards. Ventral view of a 7-setiger juvenile in A-B and dorsal view of an adult in C. The signal of the pharyngeal cilia has been omitted for clarity in A-B. Corresponding neuronal structures in B and C are colored blue. Scale bars equal 40 μm (A-B) and 280 μm (C), respectively. (A) Confocal micrograph showing tubulin immunoreactivity. The stomatogastric nerve ring (str) is connected via a pair of anterior proboscis neurites (apn) to the cerebral ganglion (cg) and via a pair of lateral proboscis neurites (lpn) to the circumesophageal connectives (cc) that pass into the ventral neurite bundle (vnb). In addition, an accessory stomatogastric nerve ring (a-str) is present posteriorly. (B) 3D reconstruction based on the CLSM image stack of the individual shown in A. (C) Semi-schematic representation based on histological sections, modified after Pilgrim [21]. Note the adapted designation of neuronal structures, the lack of a stomatogastric nerve ring (str), the presence of three instead of one anterior proboscis neurite (apn), the additional prostomial nerves (prn), the nuchal nerve (nn), and the nerves to the buccal epithelium (bun). The cerebral ganglion is differentiated into a dorsal (dl-cg) and a ventral lobe (vl-cg).