siphuncle

(sīˈfŭngˌkəl)

1. A tubelike structure in the body of a shelled cephalopod, such as a nautilus, extending through each chamber of the shell.
2. A tubular organ on the abdomen of an aphid, from which a waxy fluid is secreted as a pheromone when the insect is attacked. Also called cornicle.

Related Forms:

• si·phunˈcu·lar (-kyə-lər), si·phunˈcu·late (-lĭt) adjective