FIGURES 18‑21: Hanleya brachyplax, anatomy. 18, whole dorsal view, valves removed, showing main muscle groups, scale = 10 mm; 19, whole ventral view, foot and visceral structures mostly removed, showing main muscle groups, scale = 10 mm; 20, pericardial region, ventral view, ventral wall of pericardium and adjacent structures removed, topology of some associated organs shown, scale = 5 mm; 21, isolated gill filament as in situ, scale = 2 mm.