| 41. | Gastrioceratacean shells are variable in form with a broad whorl section and wide umbilicus.
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| 42. | Like other " Vallonia " species, the umbilicus is very wide.
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| 43. | There is no umbilicus and the last whorl with a trace of a keel.
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| 44. | In all the umbilicus is open and perforate.
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| 45. | It is canaliculate, with a wide umbilicus.
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| 46. | The canal is open and turned to the left . There is no umbilicus.
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| 47. | It has a short spire with convex umbilicus.
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| 48. | The umbilicus, which it almost wholly conceals.
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| 49. | The umbilicus is deep and very slightly contracted.
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| 50. | Surgeons make several tiny incisions near the umbilicus, through which they insert narrow tubes.
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