Shell small (SH 3.1-3.75 mm) narrow (w/h 0.38-0.4) subcylindrical in shape, teleoconch of 3.5-4 strongly shouldered compressed whorls. Last adult whorl high, rapidly constricted to siphonal canal, which is weakly defined and bent backward. Suture indistinct. Sculptured by strong slightly prosocline axial ribs (8 on last adult whorl), crossed by low spiral cords. Axial elements well pronounced on flattened whorl periphery, fading on shoulder slope. Sculpture of shoulder slope of 3 closely spaced un-dulated spiral cords. Spiral cords on whorl periphery evenly and rather widely spaced, rounded and slightly widened at intersections with axial ribs and flattened in interstices. Periphery of body whorl with 5 spiral cords succeeded by 3 slightly crenulated cords on base. Fasciole moderate with oblique cords of which upper two strong and crenulated.
Aperture narrow, outer lip clearly angulated at its lower third, thickened and incurved, with 6 equal denticles on its inside. Inner lip without dentition, bent backward at its lower part, forming edge of siphonal canal. Anal sinus moderately deep, rounded, its opening constricted; labral varix bent backward at its upper part and widened behind anal sinus.
Protoconch conical of about 3.5 evenly convex whorls, early 1.5 whorls sculptured with micro-granules arranged in spiral rows, later 2 whorls diagonally cancellate. Last whorl deeply adapically notched at its transition to teleoconch.
Colouration pale to light brown with lighter axial elements and darker interstices, protoconch brown.
Radula: description of radula morphology given in the end of the Results section.

E. compressa nov. sp. is quite distinctive and can be easily recognized from other species, described to date, thanks to its strongly shouldered compressed whorls. The species is closest probably to Exomilus edychroa (Hervier, 1897), from which, however, it can be easily distinguished by its strong axial sculpture and strongly incurved outer lip. In teleoconch morphology E. compressa nov. sp. resembles members of the genus Exomilus Hedley, 1918. However, Exomilus species are characterized by a 'cap shaped' smooth protoconch (Powell, 1966) that differs markedly from the conical diagonally cancellate protoconch of E. compressa nov. sp.

Western Pacific: Vanuatu and New Cale¬donia, depth range, living at 5-40 m.