Fig. 15

Muscular system of the lophophore of Stephanella hina. Confocal laser scanning microscopy stacks based on f-actin labelling. Volume renderings, projections or optical slices. F-actin in glow LUT. a Lateral view of a retracted polypide showing the foregut and retractor muscle. b Lateral view of the abfrontal muscle roots in the inner lophophoral concavity where the roots merge lateral to the epistome (asterisk). c Close up from the anal side showing tentacle muscles. d Details of the proximal abfrontal muscle roots. Note the zig-zag arrangement of the abfrontal muscle bands (arrows). Abbreviations: afm – abfrontal muscle band, afr – abfrontal muscle root, ep – epistome, epm – epistome musculature, fm – frontal muscle, int – intestine, lab – lateral actin-rich borders of tentacles, lb. –lophophore base, mo – mouth opening, ph – pharynx, rm. – retractor muscle