All apicomplexans are parasites. In typical parasite fashion, most have complicated life cycles, often with two different hosts. Human malaria is caused by four species of Plasmodium . . Ciliates All protists with cilia belong to one highly successful linage, placed in phylum Ciliophora. They have rows of cilia either all over the body or in specialized areas of the cell surface.
Ciliates have a very complex organization.
The cell covering, the pellicle , consists of two layers of membrane sandwiching a layer of vesicles between them. The outermost layer of cytoplasm, the cortex, contains a network of protein fibers connecting the basal bodies of the cilia. It may also contain many trichocysts , barbed or poisoned threadlike organelles that can be discharged to the outside. Most ciliates prey on bacteria, small animals, or other protists. A unique feature of all ciliates is the presence of two nuclei.