/ahr'kee oh suy"euh thid, ahr kee'euh-/ , n.
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.
[ Archaeocyath ( us ) genus name ( archaeo- ARCHAEO- + L cyathus ladle kýathos ) + -ID 2 ]