Very similar to D. emendata, but differs by its polygyrate brown protoconch, sculptured with curved axial riblets. Teleoconch whorls are white and slightly convex. Sculpture of strong, unequal and unevenly dispersed spiral chords, about five on the penultimate whorl, the adapical one being the strongest. Very fine axial dense lamellae between the chords. Aperture a little less than half height, the canal being also slightly shorter than that of O. emendata. Size: 10mm. The animal is colourless with sometimes a few opaque white spots scattered near the head. Eyes at middle of tentacle stems. The operculum is thin and corneous and has a transparent yellow colour.

Habitat: it prefers muddy detrital bottoms.
Distribution: it can be found in the circalittoral zone of the Mediterranean but, even if never common, it is present in the bathyal zone too. Imaged shells: all of them were found into rubble samples collected off Capraia Is. (Tuscan Archipelago - Italy), at 300 m depth. Notes: it is a very characteristic and unmistakable species due to its sculpture made by spiral carinae quite prominent, unequal, crossing the whole shell. Below-suture carina more prominent than the other ones. Among carinae there are thin axial lamellae never passing over the same carinae. Whorls not much convex and siphonal canal short. Protoconch polygyral, it has an axial sculpture made by little ribs bent, dark brown in colour pattern, teleconch white in colour wholly. The only Mediterranean species being alike is Drilliola emendata (Monterosato, 1872) having however a protoconch flattened and careened, white in colour as the rest of the shell. Moreover it has one siphonal canal longer and it lives in deeper water habitats. It is often found in Astropecten aurantiacus gastral cavities. » This species has been set up in many genera by several authors. We remind: Pleitrotoma, Acropota, Microdrillia, Acrobela. Drillia. that Bouchet & Waren (1980) gather under Drilliola.
Even the premature specimens are easily recognizable due to the teleconch typical sculpture and due to the protoconch sculpture and colour pattern. The adult specimens average measures are around 10 mm in height.

This is one of the commonest circalittoral Turrids in our waters. It occurs in the bathyal zone of both sides of the North Atlantic and the Mediterranean.

Distribution. The upper bathyal zone on both sides of the North Atlantic, including the Mediterranean; in the N.E. Atlantic, it reaches as far north as the middle part of the Bay of Biscay. It apparently occurs shallower in certain parts of the Mediterranean; a depth of only 45 m has been given by Gianinni (1975:90) off Corsica.
Remarks. The species shows little variation and the various names of Verrill, Watson and Dall are more a consequence of simultaneous publication than of polymorphic appearance; we have found no trace of geographical variation among the material from all parts of its distribution area in the NE Atlantic and the Mediterranean. The protoconch is evidence of planktotrophic larval development.