paramecium bursaria paramecium bursaria paramecium bursaria is a species of ciliate found in marine and brackish waters. it has a mutualistic endosymbiotic relationship with green algae called zoochlorella. the algae live inside the paramecium in its cytoplasm and provide it with food, while the paramecium provides the algae with movement and protection. p. bursaria is 80-150 μm long, with a wide oral groove, two contractile vacuoles, and a single micronucleus as well as a single macronucleus. p. bursaria is the only species of paramecium that forms symbiotic relationships with algae, and it is often used in biology classrooms both as an example of a protozoan and also as an example of symbiosis. paramecium bursaria scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: ciliophora class: oligohymenophorea order: peniculida family: parameciidae genus: paramecium species: p. bursaria binomial name paramecium bursaria(ehr., 1831) a transcriptome sequence is determined. paramecium bursaria with green zoochlorellae living inside endosymbiotically a paramecium bursaria about 100 µm long