The shell is large (maximum length 50 mm) and variable in sculpture. The spire is high and acute, consisting of six or seven angulate to convex postnuclear whorls and a protoconch of undetermined nature. The suture is distinct but not impressed. The body whorl is moderately large and fusoid. The aperture is moderately large and ovate, with a shallow, narrow anal sulcus. The outer apertural lip is very slightly erect if at all. The columellar lip is detached, erect anteriorly, and adherent posteriorly, in some cases forming a brief parietal callus. The siphonal canal is moderately long, narrowly open, and generally bent to the left.
The body whorl bears up to 11 more or less prominent varices. In most specimens we have seen, these varices are low, heavy axial ridges with a former outer apertural margin projecting moderately from the growth plane. In some cases the varices are much less broad but project more prominently. Numerous fine spiral threads cover the shell, and fimbriations are produced over the varices. In strongly sculptured forms, at the intersections of spiral and axial elements, brief spines are produced, these longest at the shoulder margin; in addition, in these forms, the spiral threads are stronger and are packed together so tightly that little if any space may be seen between them. Although the two extremes differ substantially, other specimens show an apparently unbroken intergradation between them.
Shell color is blue-white, with a thin, flat-white intritacalx, a dirty-brown periostracum, and a por-celaneous white aperture.

Description. Shell white, thick and heavy, medium-sized; spire high, whorls weakly shouldered, canal moderately long. Axial ribs 10-12, rounded to sharp, strongly developed on early whorls, sometimes faint on final whorl. Spiral cords numerous, even, separated by narrower interspaces; cords finely imbricate. Length 30-45 mm.

Type Locality and Type Specimens. Kodiak, Alaska; type material in Berlin Museum (Houart, 1985). Trophon subserratus: Vancouver Island, British Columbia; syntype material in NHML (Roth, 1981).
Distribution. Aleutian Islands, Alaska, to Cortes Bank, California [LACM 41-121.6] (32.5°N).
Habitat Rocky bottoms, 0-300 m. Occurring in the intertidal zone in Alaska, but deeply submergent at depths below 80 m in California.

Remarks. Early authors used the name Trophon tenuisculpta Carpenter, for this species, but syntype material figured by Palmer (1958, pi. 23, figs. 9-12) has a short canal; the syntypes are here identified as an immature stage of Ocenebrina interfossa (Carpenter, 1864), in which the canal had not achieved its sealed mature form.
Dall missed two early names for this species. Roth (1981) recognized Trophon subserratus Sowerby, 1880, from British Columbia, and Houart (1985) showed that the earliest name for this species is Trophon maltzani Kobelt and Kiister, 1878, which has an Alaskan type locality. However, I do not follow Houart (1985) in placing Trophon (Boreotrophon) scitulus Dall, 1891, and Neptunea (Trophonopsis) lasia Dall, 1919, in the synonymy of Scabrotrophon maltzani.

Southeastern Bering Sea to Todos Santos Bay, Baja California