| 11. | The peristome is the margin of the aperture of a gastropod shell.
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| 12. | The peristome is green to dark red and striped with purple bands.
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| 13. | The peristome is cylindrical and up to 30 mm wide.
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| 14. | The peristome is rounded and up to 12 mm wide.
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| 15. | The flattened peristome may be up to 5 mm wide.
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| 16. | The peristome is usually yellowish and may bear red stripes.
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| 17. | The narrow peristome teeth are up to 1 mm long.
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| 18. | The peristome is 1 to 2 mm wide and bears small teeth.
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| 19. | The peristome ribs are spaced 0.5 to 1 mm apart.
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| 20. | The peristome is cylindrical and up to 3 mm wide.
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