| 11. | The shells are strongly involute, subdiscoidal to lenticular.
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| 12. | The shell of " Gastrohoplites " is variably involute to evolute.
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| 13. | It had a moderately involute shell with flat sides.
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| 14. | Wb / D, and a more involute conch.
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| 15. | This has replaced hobbing for some involute gears and cutting external splines and slots.
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| 16. | The shell is small but stocky; involute or with a slightly protruding spire.
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| 17. | Once the thyroglossal duct involutes, the cells will begin to degenerate and disappear.
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| 18. | The shell is involute, moderately compressed, with a rounded and ribbed venter.
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| 19. | The shell of " Ochetoceras " is rather involute and strongly ribbed.
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| 20. | The shell itself is smooth and involute, with only the outer whorl exposed.
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