| 21. | The costa has brown subquadrate marks and the exterior border has short brown streaks, which extend over the fringe.
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| 22. | There is a subquadrate purple-blackish blotch on the dorsum towards the base, margined above with brown suffusion.
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| 23. | "Tylonautilus " has a coiled shell with a subquadrate whorl section, evolutely coiled with all whorls showing.
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| 24. | The aperture is subquadrate, nacreous, smooth within, and has a groove indicating the place of the external keel.
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| 25. | A small cloudy subquadrate dark-grey spot is found beneath the fourth dot, sometimes connected indistinctly with the third.
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| 26. | Its shell has a subquadrate whorl section, flattended venter, and fine ribs that spring in bundles from large umbilical tubercles.
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| 27. | The rhachidian tooth has a subquadrate body with winged sides and a long triangular cusp with convex sides, which are serrated.
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| 28. | The forewings are brown, with the median fascia dark brown, subquadrate and broadly developed near the basal one-third.
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| 29. | In 2000, Michael Benton noted the existence of a robust ilium that has a back end that is subquadrate instead of rounded.
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| 30. | There is a roundish spot outlined with darker before the middle, and a subquadrate spot somewhat more distinctly outlined beyond the middle.
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