As a proper noun protozoa

is protozoans; eukaryotes that are primarily unicellular, existing singly or aggregating into colonies, and usually nonphotosynthetic, placed either as:.

As a noun spirotrich is

any of a large and distinctive group of ciliate protozoa, typically with prominent oral cilia in the form of a series of polykinetids, called the adoral zone of membranelles, beginning anterior to the oral cavity and running down to the left side of the mouth.