Figure 4. CLSM images of Gastropteron rubrum radula. A. Mature inner lateral teeth. B. Whole radula. C. One side of the radular working zone. Abbreviations: a, anterior (towards the degenerative zone); BA, basis; BU, bulge; CU, cusp; DE, denticle; IL, inner lateral; l, lateral; m, medial; OL A , outer lateral A; OL B, outer lateral B; OL C, outer lateral C; OL D, outer lateral D; OL E, outer lateral E; p, posterior (towards the building zone); SB, basis of stylus; SI, side; ST, terminal stylus.