Metazoa vs. Eumetazoa

Metazoanoun

(zoology) The multicellular animals of the subkingdom Metazoa considered collectively.

Metazoa

Those animals in which the protoplasmic mass, constituting the egg, is converted into a multitude of cells, which are metamorphosed into the tissues of the body. A central cavity is commonly developed, and the cells around it are at first arranged in two layers, - the ectoderm and endoderm. The group comprises nearly all animals except the Protozoa.

Metazoanoun

multicellular animals having cells differentiated into tissues and organs and usually a digestive cavity and nervous system

Eumetazoa

Eumetazoa (Greek: εὖ [eu], well + μετά [metá], after + ζῷον [zóon], animal), also known as Diploblasts, Epitheliozoa, or Histozoa, are a proposed basal animal clade as a sister group of the Porifera. The basal Eumetazoan clades are the Ctenophora and the ParaHoxozoa.