Visualization of proposed position of teeth on radular membrane during foraging, between the two odontophoral cartilages, from different views (see axes for anatomical orientation). Silhouettes (drawn with Adobe Illustrator CS 6) of sandpapers used (from left to right: rough, medium, fine) in (A–C) are scaled identically to dimensions of teeth. Contact areas are highlighted in red. (A) Frontal view depicting the inverse w-shape of membrane. (B–C) Lateral and medial views depicting additionally a curvature of the membrane towards dorsal. (D–E) Curvature from latero-ventral and medio-ventral view. CT = central tooth, LTI = lateral tooth I, LTII = lateral tooth II, MT = marginal teeth, OC = odontophoral cartilage, RM = radular membrane, TH = thickening of membrane/ interlocking teeth.