eumetazoan

In zoology terms the difference between parazoan and eumetazoan

is that parazoan is any sponge (of the subkingdom Parazoa while eumetazoan is any animal of the subkingdom Eumetazoa (all animals except sponges.

As nouns the difference between eumetazoan and protozoan

is that eumetazoan is (zoology) any animal of the subkingdom eumetazoa (all animals except sponges) while protozoan is (cytology) any of the diverse group of eukaryotes, of the phylum protozoa, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.

As an adjective protozoan is

of, pertaining to, or characteristic of a protozoan.