Fig. 9

Immunohistochemistry for the early neural marker DLL provides further support for a cordal organization of octopus brain at stage 8. a DAPI nuclear labeling of a left eye demonstrates neural, retinal, and non-neural masses. b–d Confocal optical sections using anti-DLL (b, green in d), anti-acetylated alpha tubulin (c, acTUBA, purple in d) antibody staining, and the merged view (d) demonstrate the boundaries and distributions of the brain primordia and developing neural processes. e–h DLL and acTUBA double staining mark the cerebral (e and f), palliovisceral (e, g and h) and pedal (g and h) cords. Some neuronal fibers are seen in the enlargement view for the palliovisceral and pedal cords as indicated in H. br-pvc, brachio-palliovisceral connectives; other abbreviations as in Figs. 2 and 5. Scale bars: 100 μm