Protozoa

(pro-to-zo'ah) [G. protos, first, + zoom, animal.] subkingdom of animals, including all the unicellular animal organisms. They consist of a single cell or of an aggregation of non-differentiated cells, loosely held together and not forming ti ues; distinguished from the Metazoa which include all other animals. The Protozoa are divided into four cla es: Sarcodina,Mastigophora,Sporozoa,and Infusoria.