Fig. 6 in Neurogenesis in directly and indirectly developing enteropneusts: of nets and cords

Fig. 6 Neurogenesis in S. kowalevskii. a–C, f–k, m–o Z-projections of„ confocal microscopy image stacks. d, e, l Scanning electron micrographs (SEM). Anterior is to the right and ventral to the bottom in all images. a Overview of a dorsal kink stage. Serotonin-LIR neurons are present in the proboscis epidermis. Note the larval apical ciliary tuft. b Detail showing the developing nervous plexus in the trunk region of a dorsal kink stage. c Partial Z-projection of the anterior tip of a dorsal kink stage highlighting the absence of serotonin-LIR somata from the apical plate. d SEM of dorsal kink stage. e SEM of 1-gill-slit stage. f Partial Z-projection of the anterior tip of a 1-gill-slit stage. g Detail showing an elaborate 5-HT+ nervous plexus in the trunk region of the 1-gill-slit stage. h Overview of a 1-gill-slit stage showing the entire serotonin-LIR nervous system. i Close-up of the dorsal collar region demonstrating the 5-HT+ part in the neurulating collar cord. Double arrowheads point to dorsal connections of the anterior portion of the collar cord that is still in contact with the epidermis. k Overview of the serotonin-LIR nervous system of a 3-gill-slit juvenile. l SEM of a 3-gill-slit juvenile in lateral view. m Detail of the anterior trunk region of a 3-gill-slit juvenile showing scattered serotoninLIR bipolar neurons projecting into the ventral neurite bundle. n Detail of two biploar neurons within the proboscis epidermis. o Detail of the collar region showing 5-HT+ neurites within the subepidermal collar cord. 5- HT, serotonin; ac-α-tub, acetylated α-tubulin; at, apical tuft; cn, circumferential neurite; cc, collar cord; co, collar; dnb, dorsal neurite bundle; ep, epidermis; gs, gill slit; ms, mesocoel; nn, nervous plexus; ot, opisthotroch; pat, postanal tail; pc, protocoel; pf, perianal field; ph, pharynx; pr, proboscis; ps, proboscis stem; sn, serotonin-LIR neuron; tr, trunk; vnb, ventral neurite bundle