Protozoa are divided into three major morphologi cal types: flagellates (Step 2), amoebae (Step 72) and ciliates (Step 116). All protozoa that move ac tively, or that create currents of water while feeding, do so with cilia or flagella. These are virtually the only actively moving organelles to be found in eukaryotic cells. Cilia and flagella are difficult to see, especially if only bright-field optics are avail able (see methods, p. 13). Flagella are as long as or longer than the length of the cell and are few (eight or fewer) in number. Cilia are more numerous and relatively short.