Kovalevsky Institute of Marine Biological Research RAS 2 Nakhimov, Sevastopol, 299011, Russia Received 12.06.2016, received in revised form 10.09.2016, accepted 25.10.2016 The present article addresses an overview of different types of extreme habitats in which sessile ciliates were found. <...> Ciliates were found in different extreme habitats (marine deep waters, hypersaline, caves, and subterranean waters). <...> Authors registered 11 species of sessile ciliates in extreme environments: suctorians Corynophrya abyssalis in a hydrothermal vent fi eld (4090 m depth), Thecacineta calix in the Andaman Sea (1301 m depth), Paracineta livadiana, C. lyngbyi and peritrichous ciliate Cothurnia maritima in hypoxic/anoxic conditions of the Black Sea (80-300 m depth), suctorian ciliates Tokophrya niphargi and Spelaeophrya troglocaridis and apostome ciliate Gymnodinioides sp. in cave and subterranean waters, as well as suctorians Acinetides infundibuliformis, Acineta harpacticicola and peritrichous ciliate C. maritima in hypersaline waters (salinity from 38 ‰ to 60 ‰). <...> The possible adaptations of listed ciliates to extreme habitats are discussed. <...> It is diffi cult to identify any morphological adaptations of these ciliate species to life in extreme conditions. <...> All rights reserved * Corresponding author E-mail address: dovgal-1954@mail.ru # 385 # Igor V. Dovgal and Nelli G. Sergeeva. <...> Sessile Ciliates (Ciliophora) from Extreme Habitats Cидячие инфузории (Ciliophora) из экстремальных местообитаний И.В. Довгаль, Н.Г. Сергеева Институт морских биологических исследований имени А.О. Ковалевского РАН Россия, 299011, Севастополь, пр. <...> Основное внимание в работе уделено местообитаниям, из которых были получены оригинальные материалы: гипергалинным водоемам, глубоководным местообитаниям разного типа, а также пещерным и подземным водам. <...> Анализируются находки сукторий Acinetides infundibuliformis, Acineta harpacticicola и перитрихи Cothurnia maritima в гипергалинных <...>