Fig. 6

Development of catecholamine containing elements (blue) in P. dumerilii. Early trochophore (a-c), mid-trochophore (d,e), late trochophore (f), early metatrochophore (g,h), mid-metatrochophore (i,j), late metatrochophore (k-n). a-d,h and l are combinations of fluorescence (blue) and transmission light image (grey). a: 20 hpf, ventrolateral view showing CA-containing neurite under the prototroch (arrows) and six presumably non-nervous structures at the posterior body end (posterior cells, pc). b: 20 hpf, two CF-containing cells (cp1,2) and their fibers underlying the prototroch (arrows). Inset: high magnification of the cell cp1. c: 20 hpf, fluorescent structures at the surface of the posterior body end. d: 28 hpf, lateral view showing the cells cp1,2 and CA-containing neurites in the circular prototroch nerve (arrowheads) and two brain commissures (arrows). e: 32 hpf, lateral view on the anterior hemisphere showing the cells cp1,2 and their neurites in the circular prototroch nerve (arrowheads), two brain commissures (arrows) and a solitary fiber going towards the apical organ (open arrowhead). f: 36 hpf, ventral view showing the cells cp1,2 and CA-containing fibers in the prototroch nerve, (arrowheads), two brain commissures (arrows) and developing brain (open arrow). g: 40 hpf, ventral view showing the cells cp1,2 and cv1,2, and CA-containing fibers in the prototroch nerve, (arrowhead), two brain commissures (arrows) and developing brain (open arrow). h: 44 hpf, ventral view showing CA-containing neurites in the apical region (open arrows) and in the region of developing ventral cord (arrows). i: 48 hpf, ventral view on the left size of anterior body part showing the cells cp2 and cv2, and CA-containing neurites in the developing ventral cord (arrow), right dorsolateral nerve (arrowhead), and transverse commissure in the first chaetigerous segment (open arrow). j: 48 hpf, ventral view on the posterior body part showing CA-containing neurites in the developing ventral cord (arrows) and segmental nerves in the second and third chaetigerous segments (open arrows). k: 56 hpf, ventral view showing the cells cp1,2 and cv1,2, as well as CA-containing neurites in the prototroch nerve (arrowheads), ventral cord (arrows) and three segmental nerves (open arrows). l: 56 hpf, dorsal view on the apical part showing brain neuropil (open arrow) and neurites at the base of larval eyes (arrows). m: 56 hpf, ventral view on the posterior body part showing CA-containing neurites in the ventral cord (arrows) and three segmental nerves (open arrows). n: 56 hpf, dorsal view showing CA-containing neurites in the prototroch nerve (arrowheads), dorsolateral nerves (arrows) and segmental nerves (open arrows). Scale bars = 20 μm