Webster’s Revised Unabridged Dictionary · 1913
Isogonism
I·sog′o·nism (ī·sŏg′ō·nĭz'm), n. [Iso- + Gr. γονή offspring, generative parts.] (Zoöl.) The quality of having similar sexual zooids or gonophores and dissimilar hydrants; — said of certain hydroids.