Fig. 4

Overview of the apertural area of Hyphophorella expansa. Autofluorescence in gray, f-actin in glow, CLSM. a Oblique view of a zooid attached to the stolon capsule. b View from the frontal side of the aperture with unfolded vestibular wall bearing the gnawing apparatus. The rows of teeth are medially opposed. c Frontal overview of the muscular system of an autozooid. d Close-up of the apertural area with protruded gnawing apparatus. The teeth are now aligned in a single row. e Isolated gnawing apparatus showing autofluorscent teeth rows. Abbreviations: bvm – basal vestibular muscles, ca – cardia, cae – caecum, db – duplicature bands, fvm – frontal vestibular muscles, gwa – gnawing apparatus, lb. – lophophoral base, pdm – parieto-diaphragmatic muscles, pm – parietal muscles, pp. – pore plate, rm. – retractor muscles, sc – stolonal capsule, som – stolonal transverse muscle, st – stolon, sw – stolonal wrinkles, tm – tentacle muscles, tsm – tentacle sheath musculature, vli – vestibular lips, vwm – vestibular wall musculature