hexacoralla

from The Century Dictionary.

• One of the chief divisions of the Coralligena, in which the fundamental number of the intermesenteric chambers of the body-cavity, and likewise of the tentacles, is six; the hexamerous Coralligena, as distinguished from the Octocoralla, which are octomerous. The common Actiniidæ, or sea-anemones, are an example.