Fig. 5

Serotonin-lir nervous system of different phylactolaemate bryozoans. a & b Hyalinella punctata. a Overview of serotonin-lir nervous system at the base of the lophophore. b Close-up of the serotonin-lir nervous system of the same specimen as in (a). The arrows point to a gap in the serotonin-lir signal similar to the gap observed in the Gymnolaemata. c Serotonin-lir nervous system of Fredericella sultana including phalloidin-staining to show general structure of the lophophore. The arrow points to a tentacle that lacks serotonin-lir perikarya at its base. d Detail of the serotonin-lir nervous system and musculature of the lophophoral base of Stephanella hina. The arrows point to a neurite bundle running to a serotonin-lir perikaryon at the tentacle base that derives from the neighbouring tentacle and not the circum-oral nerve ring. . cg - cerebral ganglion, con - circumoral nerve ring, l - lophophore, la - lophophore arms, loc - lophophoral concavity, mo - mouth opening, ph - pharynx, sp - serotonin-lir perikarya, t - tentacle