Holotype: Shell small for the genus, dull surfaced, uniformly brownish white; length of aperture greater than 1/3 the length of the shell; subsutural area evenly sloping, periphery angulate. Protoconch of 3,5 relatively large whorls, postnuclear whorls 5. Axial ribs 9 on early whorls, increasing to 11 and terminating in a massive axial swelling that strengthens the lip 1/8 turn back, ribs weak in the subsutural area, angulate at the periphery, and fading at the pillar; spiral sculpture of about 7 threads on the pillar. Sinus moderately deep, U-shaped, bordered on the inside by curved parietal callus, with an angular slot behind the callus pad directed toward the suture; lip edge thin, anterior end of aperture only faintly notched; columella descending vertically, columellar callus not raised. Height, 6.1, diameter, 2.7 mm.

Cerodrillia asymmetrica has the same sized protoconch as the mainland species, C. cybele (Pilsbry & Lowe, 1932), which reaches twice the size, has fewer axial ribs and is more darkly colored. The straight columella and flaring terminal rib impart an asymmetrical outline to the shell, hence the name, derived from Greek.

Galapagos Islands, Ecuador. Type Locality: Tagus Cove, Albemarle (Isabela) Island.