Fig. 5

The nervous system in U. unicinctus larvae detected by Immunofluorescence technique with 5-HT antibody. a-b correspond to late-trochophore (LT) of U. unicinctus. c-f correspond to competent larva (CL); a and c, ventral view; b and e, dorsal view; d, lateral view; f, anterior view of CL. ao, apical organ; cc, circumoesophageal connectives; ch, chaeta; ln, longitudinal nerve fibre; mnr, metatroch nerve ring; pk, perikarya; pnr, prototroch nerve ring; tnr, telotroch nerve ring; vnc, ventral nerve cord. Scale bars: 200 μm