Taken primarily from Kozloff, 1987, 1996 p. 216 (Copyright 1987, 1996, University of Washington Press. Used in this web page by permission of University of Washington Press)
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| Lower taxonomic level | Main Page | Alphabetic Index | Systematic Index | Glossary |
| 1a | Umbilicus open (at least slightly), operculum horny | 2 |
| 1b | Umbilicus closed by a callus; operculum calcified (periostracum brown or chestnut; subtidal) | Natica clausa |
| 2a | Height up to slightly more than 3 cm; with 4 or 5 whorls; color usually whitish, grayish brown, or cream (formerly Pollinices pallidus) | Euspira pallida |
| 2b | Height commonly more than 5 cm; with 5 or 6 whorls; color cream to pinkish, beige, or golden brown | 3 |
| 3a | Inner lip of aperture with an almost tongue-shaped callus that spreads onto the body whorl, covering much of the umbilicus (thus the opening is not more than about one-eighth the diameter of the shell); height up to about 14 cm; abundant intertidally on sandflats but also subtidal (formerly Pollinices lewisii) | Euspira lewisii |
| 3b | Inner lip of aperture without an extensive callus that covers much of the umbilicus (thus the umbilicus, measured across its greatest diameter, is about one-third the diameter of the shell); height up to about 9 cm; subtidal | Polinices draconis |