Thuridilla lineolata reaches 3 cm. Small sacoglossan (Plakobranchidae) Indo-Pacific with elongated brown-purple to brown-pink body with multiple characteristic thin white longitudinal lines (hence lineolata, thin lines), wavy blue parapodia with white edge. Lives from 5 to 25 m on algae of coral reefs of central Indo-Pacific. Sap-sucker. More discreet than T. gracilis but distinct by more numerous lines. Macro photo subject for Thuridilla enthusiasts.
