White-knob Drillia

Shell size to 10 mm; shell turreted, elongate. Spire acute, comprising about 2/3 of shell length. Sculpture characteristically with two spiral cords that intersect about 10-12 weak ribs. Aperture small and slender, with thickened outer lip. Color light to dark gray-brown. White nodules form at intersection of ribs and cords.