hydrotheca

== English == === Etymology === From hydro- +‎ theca. === Noun === hydrotheca (plural hydrothecas or hydrothecae or hydrothecæ) (zoology) One of the calyculi that protect the hydranths in certain hydrozoans. ==== Derived terms ==== hydrothecal === References === “hydrotheca”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.