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Related to siphuncle: spermatophore


A tubelike structure in the body of a shelled cephalopod, such as a nautilus, extending through each chamber of the shell.

[Latin sīphunculus, diminutive of sīphō, sīphōn-, siphon; see siphon.]

si·phun′cu·lar (-kyə-lər), si·phun′cu·late (-lĭt) adj.


1. (Zoology) (in certain cephalopods) a small tube that connects shell-chambers
2. (Zoology) (of aphids) a small siphon on the abdomen by which an aphid emits sticky liquid that acts as an alarm pheromone
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References in periodicals archive ?
The series of septa are pierced and traversed in the middle by a long and thin extension of its fleshy body called the siphuncle.
The relatively thick siphuncle of Dawsonoceras resembles that of pseudorthocerids, but the spherical apex with missing cicatrix and growth lines developed on the apical part of the shell clearly suggests the position of the family Dawsonoceratidae Flower within Orthocerida (Kroger & Isakar 2006).
Passive diffusion of sediment into closed ammonite chambers is unlikely due to sediment plugging of the ammonite siphuncle and lack of fluid through flow.