Meaning of Archaeocyathid

Ar•chae•o•cy•a•thid

Pronunciation: (är"kē-ō-sī'u-thid, är-kē"u-), [key]
— n.
  1. one of the marine invertebrates of the extinct phylum Archaeocyatha, widely distributed during the Cambrian Period, having a limy, typically conical or cylindrical skeleton composed of sievelike inner and outer walls.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.