• Webster's Revised Unabridged Dictionary
    • n Hydrocaulus (Zoöl) The hollow stem of a hydroid, either simple or branched. See Illust. of Gymnoblastea and Hydroidea.
    • ***
Century Dictionary and Cyclopedia
    • n hydrocaulus In zoology, the main stem of the cœnosare of a hydrozoan.
    • n hydrocaulus The atheciferous stem of the hydroid corals: sometimes applied to the filiform process by which the sicula of the graptolite is suspended.
    • ***


Webster's Revised Unabridged Dictionary
NL., fr. Gr. "y`dwr water + a stalk


In literature:

The body bears tentacles, but shows no division into hydrorhiza, hydrocaulus or hydranth; it is temporarily fixed and has no perisarc.
"Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 2" by Various