Fig. 3

Ontogeny of the cephalopod Idiosepius notoides. All lateral views and dorsal (d)–ventral (v), anterior (a)–posterior (p) axes indicate the orientation. Core brain regions are highlighted, while innervation of peripheral target is omitted. The major ganglia are color coded: cerebral ganglia (blue), pedal ganglia (green), palliovisceral ganglia (violet), brachial ganglia (orange), and stellate ganglia (brown). The digestive tract is only indicated in the brain region, and the inner yolk duct and the entire external yolk sac are omitted for clarity. a Stage 19 embryos exhibit anlagen of all major ganglia. b The individual ganglia are connected in stage 23 embryos. Note that it is difficult to identify the origin of the brain mass connecting cerebral and pedal ganglia (herein labeled turquoise). c Stage 25 embryos exhibit a more centralized brain with the supraesophageal mass (blue), the posterior subesophageal mass (violet), the middle and anterior subesophageal mass (green), the brachial ganglia (orange), and the stellate ganglia (brown). d Hatchlings (stage 30) possess a CNS that largely resembles the one of adults. Please note that the stellate ganglia are not shown. ar arm, ey eye, fn funnel, m mantle, mo mouth and y yolk. Scale bars 150 µm