Figure 4. Homologous landmarks selected for morphometric description. A - umbo, B - ventral end of lunule, C - ventral end of anterior cardinal tooth, D - ventral end of posterior cardinal tooth socket, E - dorsal terminus of anterior adductor muscle scar, F - ventral intersection of anterior adductor muscle scar and pallial line, G - dorsal terminus of posterior adductor muscle scar, H - intersection of margin of posterior adductor muscle scar and pallial sinus, I - ventral end of escutcheon. Landmarks F and H represent the baseline ([1,0] and [0,0] respectively) for computation of shape coordinates.