Very large (up to 150 mm in length), with eight inflated teleoconch whorls.
Protoconch subcorneal, of about two and one-half volutions, first whorl small, ending at small straight varix.
Spiral ornamentation on early whorls masked by axial ornament: two rather indistinct primary spiral cords on third teleoconch whorl, one at shoulder and one at periphery, plus four minor cords, one between each pair of major cords and two on subsutural ramp. Tertiary threads gradually intercalated until body whorl patterned with complex alternation of four orders of spiral cords.
Axial ornamentation on first two teleoconch whorls of nine to 12 angulate axial ribs; on second whorl each with open spine at shoulder. On third whorl every third or fourth rib strengthened into small varix, with long, adapically directed spine at shoulder; remaining ribs rounded intervarical ridges. By fifth whorl, iritervarical ridges essentially lost; remainder of shell lacking axial ribbing but covered with strong growth lamellae which, together with spiral threads, gives shagreened appearance to entire surface. Three varices per whorl, each with complicated arrangement of primary, secondary and tertiary spines. Major spiral cords drawn out into long, closed spines, those at shoulder strongest and recurved apically, those at periphery almost as strong, not quite so recurved. Remaining major spirals each with long, closed spines, adaperturally recurved at distal ends. Secondary spiral cords produced into closed spines, somewhat shorter than those on the major cords, and more adaperturally directed. In addition, especially on posterior half of body whorl, tertiary threads produced into adaperturally directed short spines, almost at right angles to spines on major cords. On body whorl, spination pattern approximately (anteriorly from the suture): tertiary, secondary, tertiary, primary (shoulder), tertiary, tertiary, secondary, tertiary, tertiary, primary (periphery), tertiary, secondary, primary, secondary, tertiary, primary (base), tertiary, secondary. Details of spination pattern rather variable, with principal feature being three tiers of spines, one (longest spines) perpendicular to shell axis, second (shortest) at right angles to longest spines, and third set intermediate between them in direction and length. Siphonal canal with only two tiers of spines; about twelve primary spines perpendicular to axis and same number of secondary spines at right angles to primary ones; primary spines at base of canal longer than those on adjacent portion of body whorl and almost equal in length to shoulder spine.
Suture deeply but narrowly canaliculate, crossed by numerous growth lamellae.
Aperture ovate; margin of outer lip notched by extensions of median groove in spines; notches varying in size according to strength of corresponding spine. One inter-notch area on anterior third of outer lip projects to form small labral tooth. Inner lip appressed at posterior end in large flare extending up onto previous whorl and persisting as small, smooth relict structure in advance of preceding varices; anterior two-thirds of inner lip free-standing and smooth within.
Siphonal canal very long; terminations of previous canals fused into straight tube, open by narrow slit, sometimes recurved at distal tip; canal exceedingly spinose (as described above), except for anterior one-quarter of total length.
Colour of protoconch white; teleoconch creamy white to tan, with spiral cords tending to be lighter in colour than interstitial areas; aperture white, with reddish brown spots in notches.
OPERCULUM. Dark brown; subcentral nucleus, with about ten to 12 foliose concentric laminae.

This, the most popularised of the species of Murex, has a wide distribution due, presumably, to a pelagic larval stage. The possible function of the spines of this species has been discussed at length by Paul (1981), who concludes that the spines form a protective cage beneath which the animal can feed in safety. The shell of this species differs from all others in the genus in the number and arrangement of its spines. A new subspecies from Western Australian is described.