High-spired, large (up to 115 mm in length), with eight inflated teleoconch whorls. Protoconch of about one and three-quarters bulbous volutions, ending at small, crescentic varix.
Spiral ornamentation on first two teleoconch whorls of one strong cord at shoulder and second at suture. On fourth whorl, intermediate secondary cord of almost primary strength added between first two. Weak tertiary spiral threads alternate with primary and secondary cords so that surface of body whorl and siphonal canal marked by alternating spiral cords of three orders of magnitude.
Axial ornamentation on first two teleoconch whorls of eight or nine sharp angulate ribs drawn out into sharp, open lamellar spinelets at shoulder and periphery. On third whorl, every third rib strengthened into varix with long, closed, apically directed spine at shoulder; intermediate pair of ribs forming nodulose, weak axial ridges. On fourth whorl, third nodose ridge added at adapertural end of intervarical area. On subsequent whorls, intervarical ridges evanescent, replaced by numerous growth lamellae giving malleated appearance to shell surface. Three low varices per whorl, each with series of stout spines; three primary spines somewhat larger than others, shoulder spine longest and apically directed; peripheral and basal primary spines relatively straight. Secondary spine anterior to each primary spine, in some specimens almost as long as primary spines; weak, adaperturally directed, tertiary spinelets on some specimens. Siphonal canal with five, relatively short, coarse spines, slightly recurved adaperturally.
Suture simple, crossed by axial growth lamellae. Aperture ovately-rounded; margin of outer lip notched by continuation of groove on varical spines, size of notch proportionate to strength of spine. Labral tooth small; anal notch weak. Posterior end of inner lip slightly appressed, remaining three-fourths free-standing, narrow, smooth. Siphonal canal moderately long to long, distally recurved; terminations of previous canals fused into tube, open by narrow slit; almost entire length spinose.
Colour creamy white, maculated by tan blotches; spiral cords lighter in colour; aperture white, with brown spots in notches between crenulations, leading to brown lines passing into interior of shell, latter yellowish brown between these lines. OPERCULUM. Yellowish brown; subterminal nucleus with ten heavy concentric ridges, laminated on side adjacent to outer lip; indistinct median crease along length.

The shell of Murex forskoehlii may be distinguished from other species of the tribulus group that also have a protoconch of one and one-half bulbous whorls (M. falsitribulus, M. aduncospinosus and M, kerslakae n. sp.) by the small labral tooth and sculptural details. It differs from M. falsitribulus in having fewer (9 versus 12) axial ribs on early whorls and from many specimens of M. aduncospinosus and M. kerslakae, which also have nine, in having these strongly angulate, not moderately angled or rounded. It also differs from M. aduncospinosus and M. kerslakae in having more numerous spines and a shorter, bent anterior canal. This species has been regarded as M. tribulus by several authors (see synonymy) and also as M. ternispina, but Vokes (1978) pointed out that it has been misidentified.
The tendency to develop a spotted colour pattern on the shell recalls M. carbonnieri and these two species may, indeed, be closely related.

Mainly Red Sea area.