Taken primarily from Kozloff, 1987, 1996
Jump to lower taxonomic level:
| 1a | Dark lines between prominent and evenly spaced spiral ridges showing through on the inside of the aperture; axial ribs nearly parallel to the long axis of the shell, generally not extending to the body whorl except in specimens less than 3 cm high (height to 5 cm; common intertidal and shallow subtidal species) | Searlesia dira |
| 1b | No dark lines on the inside of the aperture (the spiral ridges are almost microscopic, and there are no obvious dark lines between them); axial ribs extending to the body whorl, and often somewhat irregular as well as oblique to the long axis of the shell (height to about 7 cm; moderately common subtidal species | Buccinium plectrum |