Fig. 2

Reproductive zooids of Immergentia. a Whole mount of a reproductive zooid with a brooded embryo. b – g Volume renderings based on confocal scans. b Prominent musculature of the tentacle sheath, parietal muscles and duplicature bands. c Vestibular wall muscles, embryo within the tentacle sheath and retractor muscles. d Lateral top view of embryo, tilted 180° e Side view of same embryo f Lateral top view of embryo g Lateral bottom view of same embryo, α-tubulin staining for neuronal and ciliary structures and phalloidin staining for f-actin. h Oblique tangential section of a brooding zooid with embryo. i Section of the same zooid showing lower part of the embryo. Abbreviations: ap – aperture, be – brooded, embryo, c – collar, cn – central nerve, cw – cystid wall, db – duplicature band, e – embryo, pcy – primary cystid appendage, pm – parietal muscles, pvm – parieto-vestibular muscle, rm – retractor muscle, rz – reproductive zooid, tsm – tentacle sheath muscle, vwm – vestibular wall muscle