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siphuncle

Syllabification: si·phun·cle
Pronunciation: /ˈsīˌfəNGk(ə)l
 
/

Definition of siphuncle in English:

noun

Zoology
(In shelled cephalopods such as nautiloids and ammonoids) a calcareous tube containing living tissue running through all the shell chambers, serving to pump fluid out of vacant chambers in order to adjust buoyancy.
Example sentences
  • The dorsal siphuncles of the Clymeniida tend to be larger than the ventral siphuncles of other ammonoid clades.
  • Outwardly indistinguishable from other ammonoids, clymeniids are distinguished internally by their dorsal siphuncle, contrasted to a ventral siphuncle in almost all other ammonoids.
  • Given that the shell that covers the siphuncle is its only permeable surface, the interchange of fluids can take place only through this structure.

Origin

mid 18th century: from Latin siphunculus 'small tube'.

Definition of siphuncle in:

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