Fig. 18 in Boring bryozoans: an investigation into the endolithic bryozoan family Penetrantiidae

Fig. 18 Apertural musculature, operculum, and stolon morphology of Penetrantia. a–c Musculature of aperture area in Penetrantia parva from northern New Zealand. d Operculum in P. cf. concharum from northern France. e Operculum and underlying musculature in P. concharum from Sweden. f Operculum and underlying musculature in P. parva from northern New Zealand. g Sac zooid in P. cf. concharum from northern France. h–i Stolonal network in P. cf. concharum from northern France. Asterisk indicates granules within a stolon. db duplicature band, dis diaphragmatic sphincter, oo operculum occlusor, op operculum, pd parieto-diaphragmatic muscle, pm parietal muscles, pvm parieto-vestibular muscle, s septum, st stolon, sz sac zooid, ttm tentacle muscles