| 释义 |
umbonal
adjective
biology specializeduk /ʌmˈbəʊ.nəl/ us /ʌmˈboʊ.nəl/(alsoumbonate)
having or relating to the umbo of a shell (= a raised, rounded part where the two shells of a mollusc join):
The shell has rounded, irregular ribs, with a weak ventral median groove originating in the umbonal region.
In the study of bivalves, it is often necessary to break off the umbonal infilling.
The shells are small, subtriangular in shape, with an umbonal angle of 100°.
In the molluscs, morphology of the umbonal shell may reveal much concerning type of larvae.
It has smooth, non-sulcate, asymmetrical and umbonate valves.
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