As Chrysodomus:
Shell large, short-fusiform, smooth or spirally sculptured, sometimes with rude axial ribbing or nodosities or varix-like sharp laminae; outer coat of the shell subtranslucent, the inner layer with a darker, usually purplish tint, the periostracum inconspicuous and dehiscent; last whorl longer than the spire, with a wide aperture, the outer lip in the adult flaring or subreflected, not thickened; pillar flexuous, smooth; labrum without callosities or lirae; inner side of the outer lip without liration in the typical group; the canal rather long, wide, open, and flexuous. (Dall, 1919.)
TYPE. Murex antiquus Linnaeus.
DISTRIBUTION. Circumpolar, Pacific and Atlantic, Europe, Asia, America. Fossil: Pliocene—Britain, Sicily; Pleistocene and Pliocene— California; Miocene—California and Oregon.

Shell medium (49 mm) to large (237 mm), shape broadly fusiform with short, open siphonal canal. Spire variable, ranging from short to moderately elongate, spire angle between 23 and 102 degrees. Whorls convex, shoulder occasionally angulate. Suture distinct. Subsutural slope variable, ranging from convex to concave, narrow to broad, of specific significance. Spiral sculpture variable, usually prominent, with spiral cords of different strength, of specific significance. A few specimens are smooth. Axial sculpture, when present, consisting of folds or lamellae of incremental origin (some species with foliated, projecting fronds). Aperture round or semi-oval, inside smooth without internal lirae or columellar knobs. Columella variable, ranging from slightly curved to strongly twisted, of specific significance. Outer lip thin or moderately thickened. Animal white with small brownish spots. Siphon pronounced, broad. Penis large, slightly flattened laterally, tip characteristically angular in shape, seminal opening eccentrically situated, with