Nectaries: honey-tubes, cornicles, siphuncles; q.v.
"Explanation of Terms Used in Entomology" by John. B. Smith
An extinct genus of chambered shells, allied to the Ammonites, having the siphuncle near the dorsal margin.
"Principles of Geology" by Charles Lyell
In Ammonoids the siphuncle is always marginal, and usually external.
"Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6" by Various