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p.p ., Pseudocohnilembina p.p ., Schizocaryumida p.p ., Urozonina p.p ., Thigmophryina p.p .) Size, small to large; shape, ovoid to elongate ovoid, often flattened laterally, especially in sym- biotic forms; somatic ciliation, holotrichous; oral region, typically in anterior half, with paroral dikinetid shorter than other oral structures, typ- ically by reduction of paroral a and c segments; no ribbed wall from paroral towards cytostome except in Cinetochilidae and Loxocephalidae (see NOTE); scutica typically present, often in anterior part of distinct director-meridian ; most commonly in brackish or marine habitats, includ- ing sand, with numerous species free-living, but some occurring as endocommensals in sea urchins , molluscs , coelenterates , annelids , sipunculids , and even the sea horse while others can be facultative parasites; 16 families. NOTE : Li et al. (2006) have suggested estab- lishment of the order Loxocephalida based on the sequences of the small subunit rRNA genes for Dexiotrichides and Cardiostomatella , two of the at least 14 genera that they suggest should be included in this order. We await additional sequence infor- mation before recognizing this order, but note that Jankowski (1964) has already suggested establish- ing the Suborder Loxocephalina . Family CINETOCHILIDAE Perty 1852 Size, very small to small; shape, ovoid to ellipsoid, usually flattened, sometimes look- ing very much like a baseball catcher\u2019s mitt! ; free-swimming; somatic ciliation, sparse, limited to ventral surface with one or more long caudal cilia; oral area relatively large, midventral, with pronounced ribbed wall ; in stomatogenesis, oral polykinetids 2 and 3 originating from scutica or scuticovestige ; macronucleus, globular to ellip- soid; micronucleus, present; contractile vacuole, present; cytoproct occupying all of director-merid- ian area on foreshortened ventral surface of some species; feeding on bacteria and smaller protists; in freshwater and terrestrial habitats, widespread with fewer species from brackish or marine habitats; seven genera. \u2013 Cinetochilum Perty, 1849 \u2013 Cinetozona Olmo, Tellez, & Esteban, 1998 \u2013 Platynematum Foissner, Berger, & Kohmann, 1994 \u2013 Pseudocinetochilum Obolkina, 1995 \u2013 Pseudoplatynematum Bock, 1952 \u2013 Sathrophilus Corliss, 1960 \u2013 Sphenostomella Jankowski, 1980 Family COHNILEMBIDAE Kahl, 1933 (for Lembidae) Size, medium; shape, slender, finger-shaped, tapering to point anteriorly ; free-swimming; somatic ciliation, holotrichous, with one or more long caudal cilia; oral region extending along tapered anterior, with oral polykinetid 1, very long relative to the other two oral polykinetids and with dense dikinetids of kinety n along- side it, forming a conspicuous, false \u201cdou- ble-membrane\u201d ; scutica, composed of several kinetosomes in a triangular arrangement with some 17.3 The Ciliate Taxa to Genus 415 trailing posteriorly as a file in the director merid- ian, providing the origin of kinetsomes for all oral polykinetids; macronucleus, globular to ellipsoid to ribbon-like; micronucleus, present; contractile vacuole, present; cytoproct, present; bacterivorous; in marine and saline terrestrial habitats, including Great Salt Lake; one genus. \u2013 Cohnilembus Kahl, 1933 Family CRYPTOCHILIDAE Berger in Corliss, 1979 Size, medium to large; shape, usually laterally compressed and tapered, anteriorly and posteri- orly, commonly with caudal projection bearing one or more longer cilia ; free-swimming; somatic ciliation, holotrichous, dense; oral region, usually posterior to equator with oral polykinetid 2 relatively well developed ; macronucleus, globu- lar to ellipsoid; micronucleus, present; contractile vacuole, present; cytoproct, present; bacterivorous; in marine habitats as endocommensals in the intes- tines of sea urchins , and a few species in wood-bor- ing molluscs ; nine genera. \u2013 Biggaria Aescht, 2001 \u2013 Biggariella Profant in Corliss, 1979 [nomen nudum] \u2013 Cryptochilum Maupas, 1883 \u2013 Metoikos Berger & Thompson in Corliss, 1979 [nomen nudum] \u2013 Tanystomium Berger in Corliss, 1979 [nomen nudum] \u2013 Thigmozoon Santhakumari & Nair, 1973 \u2013 Velistoma Jankowski, 1980 \u2013 Yagiua Profant in Corliss, 1979 [nomen nudum] Family ENTODISCIDAE Jankowski, 1973 Size, medium; shape, ovoid, laterally flattened (= disc-like), with narrow, truncated anterior end and, in some species, with small caudal pro- jection bearing single caudal cilium ; free-swim- ming; somatic ciliation, holotrichous; oral region, anterior, inconspicuous, with oral polykinetid 1 smaller than other two oral polykinetids; macronu- cleus, globular to ellipsoid; micronucleus, present; contractile vacuole, present; cytoproct, present; bacterivorous and detritivorous; in marine habitats as endocommensals in the intestines of sea urchins (Entodiscus ), in the mantle cavity of bivalve mol- luscs ( Pectenita ) or in the esophagus of sipunculids (Cryptochilidium ); four genera. \u2013 Cryptochilidium Schouteden, 1906 \u2013 Entodiscoides Song, Warren, & Wilbert, 1996 \u2013 Entodiscus Madsen, 1931 \u2013 Pectenita Jankowski, 1973 Family ENTORHIPIDIIDAE Madsen, 1931 Size, medium to large; shape, flattened laterally, with a prominent suture on the broad anterior end and with the posterior end tapered to tail ; somatic ciliation, holotrichous, dense, with single caudal cilium; oral region, an anterior, small, inconspicuous cavity, overhung by the frontal lobe of the body, containing a short paroral and three small oral polykinetids ; macronucleus, ellipsoid to elongate ellipsoid; micronucleus, may be multiple; contractile vacuole, present; cytoproct, present; bacterivorous and detritivorous; in marine habitats as endocommensals in the intestines of sea urchins ; one genus. \u2013 Entorhipidium Lynch, 1929 Family LOXOCEPHALIDAE Jankowski, 1964 (syn. Cardiostomatellidae ) Size, small to large; shape, elongate-ovoid, with naked apical end in some genera, and darkly- appearing cytoplasm due to mineral inclusions; free-swimming; somatic ciliation, holotrichous; somatic kineties with pronounced parateny near anterior end, appearing as perizonal kineties especially to the right of the oral region ; caudal cilium, one or more; oral region, a small ante- rior cavity, with rectangular oral polykinetids arranged in a Tetrahymena -like pattern, and a pronounced ribbed wall extending from a short paroral ; postoral suture, conspicuous, replacing the director-meridian in some species; in stoma- togenesis, all oral polykinetids originating from scutica or scuticovestige; macronucleus, globular to ellipsoid, rarely as multiple nodules; micronucleus, may be multiple; contractile vacuole, present, often at level of macronucleus; cytoproct, present, large and band-like; microphagous, typically on bacte- ria; in freshwater and occasionally brackish water 416 17. The Ciliate Taxa Including Families and Genera and terrestrial habitats, preferring polysaprobic or sapropelic environments; eight genera. \u2013 Balanonema Kahl, 1931 \u2013 Cardiostomatella Corliss, 1960 \u2013 Dexiotricha Stokes, 1885 \u2013 Dexiotrichides Kahl, 1931 \u2013 Loxocephalus Eberhard, 1862 \u2013 Paradexiotricha Grolière, 1975 \u2013 Paraloxocephalus Small & Lynn, 1985 \u2013 Paratetrahymena Thompson, 1963 Family ORCHITOPHRYIDAE Cépède, 1910 (syn. Paranophryidae ) Size, small to medium; shape, ovoid; free- swimming; somatic ciliation, holotrichous; cau- dal cilium, often present; oral region in anterior 1/3\u20131/2 body; paroral c segment (= scuticoves- tige) aligned along midventral postoral region ; macronucleus, globular to ellipsoid; micronu- cleus, present; contractile vacuole, present; cyto- proct, present; bacterivorous and histophagous; in marine habitats, especially significant as faculta- tive