Description. Shell white, aperture usually brown within; small to medium size, profile broad; anterior canal moderately long, less than length of aperture; axial lamellae 6-10 per whorl, spinose at shoulder, spiral sculpture of fine striae. Length 20-30 mm.

Type Locality and Type Specimens. Sitka, Alaska; type material not located. Boreotrophon peregrinus: Catalina Harbor, Santa Catalina Island, California, 16 fathoms; holotype: USNM 109165.Distribution. Kenai Peninsula, Alaska (59°N, 152°W), to Laguna Beach, Orange County, California (33.5°N). Habitat Rocky and gravel bottoms, intertidal to 100 m. Specimens from southern California are submergent, at depths greater than 40 m.

Remarks. Dall’s taxon Boreotrophon peregrinus is here first placed in the synonymy of this species. Boreotrophon multicostatus has been considered to be a more northern species, but there are specimens in the LACM collection from throughout the distribution. Northern specimens tend to reach larger sizes and may have more numerous axial lamellae than those occurring in southern California. The profile is broader and more cylindrical than that of Boreotrophon triangulatus and the shoulder spines are more upturned.