11
12
21
22
13
14
23
24
15
16
25
26
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Flexuosus
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Glaber
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11
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12
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21
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22
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13
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14
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23
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24
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15
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16
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25
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26
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Flexuosus
4 to 5 teeth which tend to sink in the shell at adult stage (pics 11 & 15) and are prominent when young (pics 14 & 16). The byssal notch is deep and quadrangular. Glaber 5 (younger) to 7 (older) teeth. The teeth don't sink. The younger the shell, the more prominent they are. The byssal notch is triangular. In adult shells of both species, a calcareous extension tends to separate the ctelonium from the outside world (pics 11, 13, 15, 25 & 26). |