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Morphology of velvet-like surface. (a) REM picture of velvet-like surface on a barn owl wing. View from above. (b) Higher resolution REM picture showing the overlap of the radiates of several barbs. View from below. (c) View of velvet-like surface from the side and indication of thickness and angulation parameters. Scale bars are: (a) 1 mm, (b) 200 µm and (c) 100 µm.
