Fig. 8
From: Development of the nervous system in Platynereis dumerilii (Nereididae, Annelida)
Development of the dorsal sensory structure in P. dumerilii. Mid-trochophore (a), late trochophore (b), early nectochaete (c), and mid-nectochaete (d). Dorsal views, acetylated tubulin-like immunoreactivities are presented as negatives. a: 28 hpf, bipolar neuron (arrow) and the cell fd are located dorsally on both sides of the prototroch and send fibres into the prototroch nerve. b: 36 hpf, the cell fd and the bipolar sensory cell (arrow) with the short apical fibre (open arrowhead) and basal fibre (arrowheads) running into the apical neuropil. c: 68 hpf, the cell fd and the bipolar sensory cell (arrow) with the apical ciliated fibre (open arrowhead); pn – prototroch nerve. d: 72 hpf, the above listed structures show signs of degeneration. Scale bars = 20 μm