Fig. 9

Syllis tyrrhena. Innervation of prostomium and anterior segments. a: Maximum intensity projection of dorsal sections, α-tubulin-lir. Several fibre bundles (red arrow) separate from the main palp neurite bundle and enter the palps. The neuropil of the brain appears relatively uniform, individual commissures are not visible. b: Maximum intensity projection, ventral, α-tubulin-lir. The black arrowhead indicates the neurite bundle forming ventral, dorsal and lateral longitudinal neurite bundles. Red arrows indicate neurite bundles which separate from the main palp neurite bundle. c: Maximum intensity z-projections, dorsal, serotonin-lir. Several perikaryal are visible behind the brain. d: Maximum intensity z-projections, ventral, serotonin-lir. e: Maximum intensity z-projection of α-tubulin-lir (grey) and cell nuclei (magenta), dorsal. Yellow arrowheads indicate dorsolateral ciliary patches on anterior segments. f: Maximum intensity z-projection, resliced saggital sections, combined α-tubulin-lir (grey), serotonin-lir (orange) and cell nuclei (magenta). The posterior nerves connect directly to the primary sensory neurites of the nuchal organ g: Maximum intensity z-projection of ventral planes of α-tubulin-lir. A black arrowhead indicates the neurite bundle forming dorsal, lateral and ventral longitudinal neurite bundles. Scale bars = 50 μm. Abbreviations: acvr – anterior dorsal commissure of vrcc; ae – anterior eye; br – brain; cno – cilia of support cells of nuchal organ; dcs – dorsal cluster of somata; dln – dorsal longitudinal neurite bundle; drcc – dorsal root of circumoesophageal connective; lan – neurite bundle innervating lateral antenna; lfs – laterofrontal sense organ; lln – lateral longitudinal neurite bundle; man – neurite bundle innervating median antenna; mcvr – median dorsal commissure of vrcc; ndln – fibres from nuchal organ joining dorsal longitudinal neurite bundle; nn – nuchal neurite bundle; pa – palp; pcb – posterior dorsal commissure of the brain receiving fibres from drcc; pcs – ciliary patches on palps; pk – serotonin-lir perikarya; pn1 – main palp neurite bundle; pn2 – palp neurite bundle from drcc; pn3 – palp neurite bundle from vrcc; pon – posterior neurite bundle; smf – spherical median front of the brain; sn1, sn2 – segmental neurite bundles of tentacular segment; stgn1–5 – stomatogastric neurite bundles 1–5; tcn – neurite bundle innervating tentacular cirrus; vln – ventral longitudinal neurite bundle; vrcc – ventral root of circumoesophageal connective