polyactinia

from The Collaborative International Dictionary of English v.0.48

Polyactinia \Pol`y*ac*tin"i*a\, n. pl. [NL. See {Poly-}, and
   {Actinia}.] (Zool.)
   An old name for those Anthozoa which, like the actinias, have
   numerous simple tentacles.
   [1913 Webster]