Fig. 5 in Neurogenesis in directly and indirectly developing enteropneusts: of nets and cords

Fig. 5 Neurogenesis in the 2-gill slit juvenile of B. misakiensis. a, b„ Scanning electron micrographs: c–i Z-projections of confocal microscopy image stacks. Anterior is to the right. a Dorsolateral view of a 3-day-old settled juvenile. b Higher magnification of the two gill slits and the dorsal tongue bars. c Overview of the 5-HT+ NS of a 3-day-old juvenile. d The collar cord is composed of three 5-HT+ neurite bundles of which the median one projects posteriorly into the dorsal nerve cord. e Detail of the ventral 5-HT+ neurite bundle with numerous incoming circular neurites emerging from lateral bipolar neurons. f Detail of the anterior part of the dorsal 5-HT+ neurite bundle and epidermal collar region. This part is discontinuous with the posterior part of the 5- HT neurite bundle shown in g, see also double arrowheads and dashed area. g The posterior part of the dorsal 5-HT+ neurite bundle contains few serotonin-LIR neurites and is discontinuous with the anterior part of the 5- HT neurite bundle, see double arrowheads and dashed area. h Partial Zprojection of a sagittal scan of the dorsal collar region. The collar cord comprises ventral neurite bundles and a dorsal sheath of somata, which are not serotonin-LIR positive. i Close-up of a part of the proboscis region showing the 5-HT+ bipolar neurons and the basiepidermal nervous plexus. 5-HT, serotonin; a, anus; ac-α-tub, acetylated α-tubulin; cn, circumferential neurite; cc, collar cord; ci, cilia; co, collar; dnb, dorsal neurite bundle; ep, epidermis; gs, gill slit; msp, mesocoel pore; nn, nervous plexus; onr, opisthotroch nerve ring; pnr, prebranchial nerve ring; pr, proboscis; ps, proboscis stem; sn, serotonin-LIR neuron; tb, tongue bar; tm, trunk musculature; vnb, ventral neurite bundle