There are hundreds of species of amoebas throughout the world. They live in both fresh and salt water. Amoebas move by means of extending pseudopods. Pseudopods are flowing projections of cytoplasm that extend and pull the amoeba forward. They are also used for surrounding and engulfing food particles.
Some amoebas are parasitic.
Phylum Ciliophora Ciliates are heterotrophic unicellular organisms that move via rows of cilia on the external surface of the body. There is a high level of complexity in this phylum. Ciliates have a gullet and a contractile vacuole which is used to regulate water balance. Another unique feature is that they contain two different types of nuclei called macronuclei and micronuclei. Vorticella is an example of a stalked ciliate.