Taken primarily from Kozloff, 1987, 1996
Jump to lower taxonomic level:
| 1a | Width of columellar callus, at the base of the body whorl, about one-third of the height of the shell; height up to 3 cm | Olivella biplicata |
| 1b | Width of columellar callus, at the base of the body whorl, about one-fourth the height of the shell; height not often more than 2 cm | 2 |
| 2a | Diameter about half the height; often with brown, zigzag lines running lengthwise (not common north of Oregon) | Olivella pycna |
| 2b | Diameter about two-fifths of the height; brown lines, if present, not zigzag | Olivella baetica |