Paramecium bursaria, the green 'slipper animalcule' contains symbiotic algae of the genus Chlorella. The Paramecium acts as a greenhouse. The relation has a mutual benefit. The Chlorellas are protected and provide the Paramecium with nutrition. In order to make sure the algae can perform photosynthesis this Paramecium moves towards the light.

Part of the Collection of the Ciliate Centre of the Micropolitan Museum © Wim van Egmond