Holotype: Shell of medium size for the genus; surface chalky white, entirely colorless; aperture about 1/3 the length of the shell; suture moderately impressed, undulating, immediate subsutural area swollen, producing an inflated subsutural cord with a constricted channel below. Protoconch of 2,5 smooth whorls with small, immersed tip (paratypes), postnuclear whorls 11. Axial ribs 8 on early whorls, increasing to 10 on penultimate whorl, extending suture to suture on early whorls but stopping at the subsutural groove on mature whorls, narrowed and raised on passing from body whorl to pillar, obsolete upon pillar; back of last whorl with an axial rib subtending the sinus, preceded by a massive axial rib 1/4 turn back; spiral sculpture wanting. Sinus deep, U-shaped, strongly outward projecting, bordered on the inside by curved parietal callus; lip edge thin, stromboid notch weak; anterior canal scarcely defined, notched, inner lip slightly raised above the pillar. Height, 20.7, diameter, 7.8 mm.

Drillia inornata differs from the other Drillias in lacking spiral sculpture and having a swollen subsutural cord. The name is Latin, unadorned, with reference to its absence of color and spiral sculpture.

Pacific Central America. Mexico, Costa Rica. Type Locality: Off Puerto Refugio, Angel de la Guarda Island, Gulf of California.