Figure 23

Ventral nerve cord and muscle development of P. dumerilii , 72 hpf - 5 days post fertilization, ventral view, anterior up. The age of the larvae in each row is given in the lower left corner of the first picture of each row. The displayed staining is indicated at the bottom of each column. A, G, M: The ventral nerve cord is well visible. The connectives become broader. Therefore, the commissures appear shorter than in previous stages. The segmental nerves (sn) become well visible. Antennal nerves (an) and palpi nerves (pln) are visible. B, H, N: More serotonergic cells develop in the ventral nerve cord (white arrow heads). The unpaired serotonergic cell, which was marked by a white star in figure 7, 10, 11, 13, 15, 18, 21, 19, 26 and 28 is not visible anymore. C, D, I, J, O, P: Parapodial muscles (ppm) and oblique muscles (om) as well as the unpaired medial ventral longitudinal muscle (mvlm) are well visible and a complex set of muscles develop in the head region, e.g. the antennal muscles (antm). E, K, Q: The dorsal branch of the anterior cirri (adc) begins to elongate. CLSM microscopy, maximum projection, Imaris surpass mode. Scale bar in all images 20 μm. Further abbreviations see abbreviations list.