siphuncle

/sahy-fuhng-kuhl/US // ˈsaɪ fʌŋ kəl //

虹膜,虹口区,虹吸管,虹吸效应

Definitions

n.名词 noun

1
- : the connecting tube that passes from the end of the body through all of the septa to the innermost chamber.
- : Entomology. an aphid cornicle.

It is peculiar to the louse tribe (Pediculid), and it consists of the tubulet (Tubulus), and siphuncle (Siphunculus).
In Ammonoids the siphuncle is always marginal, and usually external.
The siphuncle in the Nautilus pierces the centres of the septa, and in fossil Nautiloids it is usually central or sub-central.
Shell straight or slightly curved, with a simple aperture, large terminal chamber and cylindrical siphuncle.
Shell straight, with wide margina siphuncle, necks produced into tubes fitting into one another.