Diagnosis: Shell with oblong body whorl and acute, non-papilliform apex, b/1 0,31-0,35, a/1 0.32-0,35: whorls with angular to shouldered periphery, situated at or just below middle; shoulder slope shallowly concave, subsutural cord weak or absent; axial ribs tuberclelike, more or less peripheral, seldom reaching lower suture, 10-12 on penultimate whorl, crossed by very fine spiral threads; labrum foreshortened, siphonal canal fairly deeply and obliquely notched: parietal tubercle relatively weak, not constricting anal sinus; brown with pale to white nodules; protoconch breadth 0.95-1,20 mm: attains 19,8 mm.
Description: Shell narrowly claviform (b/1 0.31-0.35, a/1 0,32-0,35, body whorl rather oblong, spire acute, apex not papilliform, teleoconch whorls about 7; first 2-3 whorls weakly convex, rest with a rounded peripheral angle situated at or just below midwhorl, forming a weak shoulder on last whorl or two, shoulder slope shallowly concave with at most a slight subsutural cord: left side of base of body whorl concave with a well-developed fasciole and usually a chink-like umbilicus next to columella callus. Aperture narrowly oblong-lanceolate, rather linear, but greatest width more or less median, labrum markedly foreshortened, rendering base oblique, siphonal canal moderately wide, bent slightly to right, its termination rather deeply indented dorsally; columella straight or slightly convex, labial callus thick, its outer edge slightly free on columella, parietal pad small to moderate, not constricting entrance to anal sinus; labrum very gently convex in sideview, with shallow but distinct stromboid notch, anal sinus deep. U-shaped, bordered by weakly alate expansion of lip. Sculptured by rather low, largely peripheral, tubercle-like axial ribs (sometimes almost obsolete on later whorls) and very fine spiral threads: growth-lines coarse, an occasional one very coarse; a weak prelabral varix sometimes present in narrow examples. Axial ribs feeble on 1st whorl, on 2nd forming 10-11 low axial nodules above suture; penultimate whorl with 10—12 ribs, body whorl with 12-15 (becoming weak immediately behind lip); crests rounded in section, with gradually sloping sides, opisthocline, equal to intervals, evanescing abruptly above shoulder, seldom reaching suture below, and on body whorl becoming obsolete above suture-line or at least by level of parietal tubercle. Spiral threads feeble on early whorls, on later ones fine, close and uniform, about 29-38 on penultimate whorl, often weak on shoulder slope, on base of body whorl wider and more close-set than elsewhere. Colour light to deep brown, tubercles usually paler to yellowish-white at periphery. Dimensions: 17,2 x 5,8 mm (holotype); 19,8 x 6,2 mm, 14,5 x 5,0 mm (largest and smallest paratypes). Protoconch narrowly pupoid-conical, of slightly more than 2 whorls, first half-whorl small and depressed; smooth, except for sinuous growth-lines and about 8 feeble spiral threads near termination; lip strongly reversed-sigmoid; breadth 0,95-1,20 mm, height 1,15-1,35 mm (b/h 0,77-0,89). Operculum oblanceolate, with sharp apex, growth-lines coarse, translucent yellowish. Body greyish-white, speckled with black. Tentacles consisting mainly of a basal lobe bearing the eye, with only a short digitiform tip. No radula located.

Broad examples of Drillia spirostachys are somewhat similar to narrow examples of D. lignaria, and it is not impossible that the former may prove to be an eastern subspecies of lignaria. However, spirostachys appears to be always distinguishable from lignaria by its somewhat narrower form, more elongate body whorl, foreshortened outer lip, slightly narrower and more linear aperture, deeper siphonal notch and slightly more numerous, discretely tuberculate (occasionally almost obsolete) axials. Narrow examples of D. spirostachys resemble Paracuneus immaculatus (Tenison-Woods, 1876), the type species of Paracuneus, in shape and general sculpture.

South-Africa. Continental shelf from Natal to East London, 60-300 m.