| 21. | The dorsal surface of the head is covered by small, imbricate, keeled scales.
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| 22. | Air pores occasionally break through the dorsal surface, giving the thallus a dimpled appearance.
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| 23. | The dorsal surface is rough for the attachment of ligaments.
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| 24. | Females have a gray dorsal surface and a bluish underside.
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| 25. | Males may be patternless or have reticulations or chevron patterns on their dorsal surface.
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| 26. | The dorsal surface of the turtle's head has a single pair of prefrontal scales.
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| 27. | The scales on the dorsal surface are relatively small, uniformly overlapping, and slightly keeled.
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| 28. | The dorsal surface of the skin is a rough shagreen.
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| 29. | The dorsal surface is covered with white and black patterns that can vary considerably.
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| 30. | A thin film of chitin covers the entire dorsal surface.
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