haplokinety (Hk) and polykinety (Pk), actually peniculus 1 (P1) encircle the peristome, accompanied along part of their length by the germinal field (GF). As the Hk and Pk enter the infundibulum they are joined by peniculus 2 (P2) supported along the length by the fila- mentous reticulum (FR). Peniculus 3 (P3) and the cytopharynx (Cph) are at the base of the infundibulum. B Patterns of oral polykinetids in spirotrich ciliates. ( a ) The “closed” pattern of oral polykinetids in choreotrich ciliates, such as Tintinnopsis and Strobilidium . ( b ) The “open” pattern of an outer “collar” and ventral “lapel” of oral polykinetids in genera such as the stichotrich Halteria and the oligotrich Strombidium Fig. 2.5. (continued) the base of an anterior oral cavity. ( c ) Cytostome at the base of a ventral oral cavity with an ill-defined opening. ( d ) Cytostome at the base of a subapical atrium (At), which is not lined with cilia. ( e ) Cytostome at the base of a ventral oral cavity with a well-defined opening (dashed line). ( f ) Prebuccal area (PbA) preceding a well-defined oral cavity. ( g ) Oral ciliature emerging onto the cell surface in a prominent peristomial area (Pst). D Schematic arrangement of the nematodesmata in the cyrtos of two cyrtophorians , Aegyriana ( a ) and Brooklynella ( b ). Each nematodesma is topped by a tooth-like capitulum (Cap) used in ingestion Fig. 2.7. Somatic and oral infraciliary patterns, as revealed particularly by Chatton-Lwoff silver impregnation. ( a ) The thigmo- trich Proboveria showing the positions of the contractile vacuole pore (CVP) and the placement of Kinety 1 (K1) and Kinety n (Kn). Oral structures include two oral polykinetids (OPk1, OPk2) and the paroral (Pa) or haplokinety (HK). An apical view is to the top right of the cell. ( b , c ) Ventral ( b ) and dorsal ( c ) views of the thigmotrich Ancistrum . Note similar somatic and oral features to Proboveria . The dorsal anterior has a zone of densely packed thigmotactic ciliature (TC). ( d ) Posterior region of the hymenostome Curimostoma , showing a secant system (SS). ( e ) Anterior ventral surface of Tetrahymena , showing primary ciliary meridians (1CM) and secondary ciliary meridians (2CM) of the silver-line system, as well as intermeridi- anal connectives (IC) and circumoral connective (CoC). Two postoral kineties (K1, Kn) abut against the oral region, which is composed of three membranelles (M1, M2, M3) and a paroral (Pa) or haplokinety (HK) from which the oral ribs (OR) extend towards the cytostome. Somatic kineties abut on a preoral suture (PrS). ( f ) Apical (left) and antapical (middle) views of Fig. 2.8. Variations in form. A A variety of lorica types. ( a ) The peritrich Cyclodonta . ( b ) The peritrich Cothurnia . (c–g ) Tintinnid loricae, including Eutintinnus ( c ), Salpingella ( d ), Dictyocysta with its perforated collar (Col) ( e ), Metacylis ( f ), and Tintinnopsis ( g ). ( h ) The folliculinid Metafolliculina . ( i ) The suctorian Thecacineta showing its sucking tentacles (SuT). ( j ) The peritrich Pyxicola with its ciliated oral (O) end, protected by the operculum (Opr) when it withdraws into the lorica. Ab, aboral . ( k , l ) The tube-like loricae of the colpodean Maryna ( k ) and the stichotrich Stichotricha ( l ). ( m ) The lorica or theca of Orbopercularia , which contains several zooids. B Colonial organizations. ( a ) The catenoid colony of the astome Cepedietta . ( b ) The spherical and dendritic colony of the peri- trich Ophrydium with its zooids (Z) embedded in the matrix. ( c ) The dendritic colony of the peritrich Epistylis . ( d ) The arboroid or dendritic colony of the suctorian Dendrosoma Fig. 2.7. (continued) Tetrahymena pyriformis , showing placement of the postoral kineties (POK), contractile vacuole pores (CVP), and cytoproct (Cyp). Antapical view of Tetrahymena setosa showing the placement of the polar basal body complex (PBB). ( g ) An apical view of Colpoda magna in a late stage of stomatogenesis. Kinety 1 (K1) is the rightmost postoral kinety. (h ) Ventral view of the peniculine Frontonia showing somatic kineties converging on preoral (PrS) and postoral (PoS) sutures . The oral region is bounded on the right by the densely packed ophryokineties (OK) and contains on its left the three peniculi (P1, P2, P3). ( i ) Ventral view of the scuticociliate Paranophrys , showing features described previously (CVP, Cyp, HK, OPk1, OPk2, OPk3, Pa, PBB). The director meridian (DM) is a silver-line that extends posteriorly from the scutica (Sc). ( j ) Cytopharyngeal baskets of three ciliates: the rhabdos of a prorodontid (upper); the nasse or cyrtos of the nassophorean Nassula , bound in the middle by an annular band (ABd); and the cyrtos of the cyrtophorian Chilodonella . ( k , l ) Ventral ( k ) and dorsal (l ) views of the hypotrich Euplotes showing the silver-line system of both surfaces. The large dark spots on the ventral surfaces are the bases of cirri (Cir) while the smaller dots in the dorsal kineties are sensory (SB) or dorsal bristles 70 2. Glossary of Terms and Concepts Useful in Ciliate Systematics Fig. 2.9. A Cysts . ( a–e , g , i ) Resting cysts of the haptorian Didinium ( a ), the suctorian Podophrya ( b ), the hypotrich Euplotes ( c ), the clevelandellid Nyctotherus with its operculum (Opr) ( d ), the stichotrich Oxytricha ( e ), the colpodean Bursaria with its micropyle (Mpy) ( g ), and the peritrich Vorticella ( i ). ( f , h ) Division cyst of the colpodean Colpoda (f ; Note the macronuclei (Ma) and micronuclei (Mi) ) and the ophryoglenid Ophryoglena with its many tomites ( h ). Glossary 71 Fig. 2.10. Patterns of microtubules in cross-sections of various tentacle -like structures. ( a–e ) Sucking tentacles of the suctorians Sphaerophrya ( a ), Acineta ( b ), Loricodendron ( c ), Dendrocometes ( d ), and Cyathodinium ( e ). Note that there is an outer ring(s) enclosing the ribbon-like phyllae . ( f ) The sucker of the rhynchodid Ignotocoma . ( g ) The prehensile tentacle of the suctorian Ephelota . ( h ) The toxicyst-bearing, non-sucking tentacle of the haptorian Actinobolina Fig. 2.9. (continued) ( j ) Resting cyst of the apostome Spirophrya , which is attached to the crustacean host cuticle and encloses the phoront (Phor) stage. B Attachment structures and holdfast organelles . ( a–c ) The attachment suckers (S) of the clevelandellid Prosicuophora ( a ), the scuticociliate Proptychostomum ( b ), and the astome Steinella ( c ). ( c–e ) Spines (Sp) may aid attachment in the astomes Steinella ( c ), Maupasella ( d ), and Metaradiophrya ( e ). ( f ) Posterior end of a dysteriid phyllopharyngean showing its attachment organelle (AO) or podite (Pod) at the base of which is a secretory ampulla (AS). CV, contractile vacuole . ( g , h ) Denticles (Dent) and border membrane (BM) are organized in the holdfast disk of the mobiline peritrichs Trichodinopsis ( g ) and Trichodina ( h ). ( i , j ) Longitudinal section of the attachment stalks of a peritrich with a central spasmoneme (Sn) ( i ) and an eccentric spasmoneme ( j ). C Extrusomes . (a ) The rhabdocyst of the karyorelictean Tracheloraphis . ( b ) A mucocyst , resting (left) and discharging (right). ( c ) The clathrocyst of the haptorian Didinium . ( d ) Resting haptocyst of the suctoria (left) and their distribution at the tip of the attachment knob (AK) of the sucking tentacle. ( e ) Toxicyst , resting (left) and ejected (right). Not to the same scale. ( f ) Trichocyst of Paramecium , resting (left) and ejected (right). Not to the same scale Fig. 2.11. Various kinds of fission processes.