umbonal

/uhm-buh-nl/US // ˈʌm bə nl //

脐带,伞状物,伞状花序,伞状的

Definitions

adj.形容词 adjective

1
- : having the shape or appearance of an umbo; bosslike: an umbonal structure.
- : of, relating to, or near the umbo: the umbonal region.

Valves smooth, thin, brittle; scuta with internal umbonal teeth on both sides.
Right-hand scutum alone furnished with an internal umbonal tooth: uppermost part of peduncle dark-coloured.
Its shell is considerably twisted just below the umbonal region, while its whole surface is densely striated.
Ligament wanting; shell gaping, with a styloid apophysis in the umbonal cavities.