Figure 21

Ventral nerve cord and muscle development of P. dumerilii , 64 - 70 hpf, 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, S: The connectives (con) and commissures (com) are intensely stained. The connectives have a band-like shape. B, H, N, T: Additional serotonergic cells develop in the ventral nerve cord (white arrow heads), in addition to the unpaired serotonergic cell (white star). C, D, I, J, O, P, U, V: Parapodial muscles (ppm) and oblique muscles (om) as well as the unpaired medial ventral longitudinal muscle (mvlm) are well visible. E, K, Q, W: The metatroch (mt) becomes visible posterior to the prototroch (pt) around 66 hpf. F, L, R, X: The parapodia (pp) grow in size. CLSM microscopy, maximum projection, Imaris surpass mode. Scale bar in all images 20 μm. Further abbreviations see abbreviations list.