drawings of two somatic kinetids from four classes of ciliates, two with somatic monokinetids ( a , b ) and two with somatic dikinetids ( c , d ). ( a ) The somatic kinetids of the Class OLIGOHYMENOPHOREA . Note that the transverse ribbons (T) are radial to the perimeter of the kinetosome (Ks). The kinetodesmata (Kd) from adjacent kinetids overlap but the postciliary ribbons (Pc) do not. ( b ) The somatic kinetids of the Class LITOSTOMATEA . Ciliates in this class typically have two sets of transverse ribbons (T1, T2) and the postciliary ribbons often lie side-by-side in the cortex. ( c ) The somatic kinetids of the Class HETEROTRICHEA in which the postciliary ribbons (Pc) overlap laterally to form the Km fiber or postciliodesma (Pcd). ( d ) The somatic kinetids of the Class COLPODEA in which the trans- verse ribbons (Tp) of the posterior kinetosome of the dikinetid overlap to form the transversodesma (Td) or LKm fiber Fig. 2.1. (continued) ( e ) has a kinetodesma (Kd) and postciliary ribbon (Pc) on its right and a transverse ribbon (T) on its left (cf. Fig. 2.1E). C A pair of kinetosomes (upper) and a dyad (lower) in relation to the body axis (anterior is towards the top of the page). D Cross-section of a kinetosome as viewed from the outside of the cell showing the numbering system of Grain (1969) on the outside of the triplets and the numbering system of Pitelka (1969) on the inside of the triplets. The postciliary ribbon (Pc) is numbered as 9 or 5, respectively. E Examples of somatic kinetids of ciliates from different classes showing the diversity of patterns with dikinetids ( a–d ) and monokinetids ( e–i ). Note the kinetodesma (Kd), postciliary ribbon (Pc), and transverse ribbon (T) associated with kinetosomes (Ks). A retrodesmal fibril (Rd) may extend posteriorly to support the postciliary ribbon and a cathetodesmal fibril (Cat) may extend towards the left into the pellicle. Occasionally a transverse fibrous spur (TFS) replaces the transverse micro- tubules. ( a ) The karyorelictean Loxodes . ( b ) The heterotrichean Spirostomum . ( c ) The clevelandellid Sicuophora . ( d ) The clevelandellid Nyctotherus . ( e ) The rhynchodid Ignotocoma . ( f ) The peniculid Paramecium . ( g ) The scuticocili- ate Porpostoma . ( h ) The scuticociliate Conchophthirus . ( i ) The astome Coelophrya 64 2. Glossary of Terms and Concepts Useful in Ciliate Systematics Fig. 2.3. Drawings of specimens after they have been stained by various silver impregnation techniques . ( a–c ) The dry silver technique of Klein showing the secant system (SS) or preoral suture (PrS) of Colpidium ( a , Klein) and Ancistrum ( b , Raabe) and the paratenes (Par) and polar basal body (PBB) of Trimyema ( c , Jankowski). ( d ) Dexiotricha (Jankowski) stained by the von Gelei-Horváth technique to reveal the paratenes (Par), the contractile vacuole pore (CVP) and the polar basal body (PBB). ( e–i ) The Chatton-Lwoff wet silver technique, showing the sensory bristles (SB) of Monodinium ( e , Dragesco), the contractile vacuole pore (CVP) of Glaucoma ( f , Corliss), the preoral suture (PrS) of Pleurocoptes ( g , Fauré-Fremiet), paratenes (Par) and postoral suture (PoS) of Disematostoma ( h , Dragesco), and the preoral suture (PrS), contractile vacuole pore (CVP), cytoproct (Cyp), and pavés (Pav) of the hypostomial frange (HF) of Obertrumia ( i , Fauré-Fremiet). ( j–l ) Protargol or silver proteinate impregnation, showing the cirri (Cir) of Aspidisca ( j , Tuffrau) and Stylonychia ( l , Dragesco), and the cilia of Phacodinium ( k , Dragesco). B Secant systems (SS) where somatic kineties converge on the left ventral ( a ) and right dorsal ( b ) cortex of the clevelandellid Nyctotheroides , ( c ) the astome Paracoelophrya , and ( d ) the clevelandellid Sicuophora Fig. 2.4. (continued) showing the complex pattern of denticles in the aboral sucker. M , N Euplotes sp. (Tuffrau) showing the complex pattern of the argyrome ( M ) after wet-silver staining and the complex subpellicular rootlets ( N ) after protargol staining. O Brooklynella hostilis (Lom) showing two circumoral kineties just anterior to the oral region and the transpodial kineties (TR) encircling the podite at the posterior end. P The scuticociliate Pleuronema (Small) in early stomato genesis , demonstrating the scutica (Sc). Q , R Ventral view ( Q ) of Philaster sp. and a detail of the structure of its oral polykinetid 2 (OPk, R ). S The tintinnid Tintinnopsis (Brownlee) with its two macronuclear nodules, residing in its lorica ( L ) Fig. 2.4. Photomicrographs of specimens treated by various techniques of silver impregnation. A–D , F, G , K–M – Chatton-Lwoff technique. J Rio-Hortega method. E , H, I , N–S – Protargol or silver proteinate impregnation . A Tetrahymena pyriformis showing the microstome-type oral apparatus with a paroral and three membranelles (inset). Note the contractile vacuole pores (CVP). B Macrostome form of Tetrahymena patula adapted to ingesting smaller ciliates with view of the transformed oral apparatus (inset). C Urocentrum turbo . D , E Tetrahymena sp. showing the director meridian (DM) and the cilia (C). F Apical (upper) and antapical (lower) poles of Tetrahymena setosa . Note the contractile vacuole pores (CVP). G , H Ventral view of Glaucoma scintillans , showing its oral polykinetids (OPk, G ) and preoral suture ( H ). I Preoral suture of Colpidium sp. J Dexiotricha (Fernández-Galiano) showing paratenes to the anterior right of the cell and demonstrating short kinetodesmata. K Paramecium sp. (Dippell) ventral view (left) showing the cytoproct (Cyp) and a dorsal view with the two densely staining contractile vacuole pores . L Ventral view of Trichodina sp. (Lom) 66 2. Glossary of Terms and Concepts Useful in Ciliate Systematics Fig. 2.5. Oral structures of ciliates. A Oral ciliature . ( a ) The heterotrich Gruberia covered by somatic cilia ( C ) and with an oral region bordered by an adoral zone of oral polykinetids (OPk) on its left and a paroral (P) on the right. (b ) The hypotrich Euplotes showing its complex cirri (Cir) and an adoral zone of oral polykinetids (OPk). ( c ) The scuticociliate Cyclidium covered by somatic cilia (C) with a specialized caudal cilium (CC) extending to the posterior and the cilia of the paroral (P) raised in a curtain-like velum . ( d ) The haptorian Didinium with its anterior feeding protuberance surrounded by a ciliary girdle (CG). ( e ) The nassophorean Nassulopsis showing its adoral ciliary fringe (ACF) of pavés . ( f ) A longitudinal section through the anterior end of the entodiniomorphid Epidinium , showing the retractor fibres (RF), skeletal plates (SP) supporting the cortex, and the compound ciliary organellar complexes, called syncilia (Syn) surrounding the oral region. B Three-dimensional representation of the complex bundle of microtu- bules that makes up a typical nematodesma (Nd). C Schematic representations of oral regions. ( a ) Apical cytostome (Cs) and cytopharynx (Cph) of a prostomial form. Note the cytostome appears as a ring in ( b–g ). ( b ) Cytostome at Glossary 67 Fig. 2.6. Spiralling oral structures. A Oral structures of peritrichs . ( a ) The general arrangement of the peritrich oral region with the cytostome (Cs) at the base of a deep infundibulum (Inf), which leads out to the peristome (Pst) on which the oral ciliature spiral. ( b ) Varying degrees of complexity in the oral spiral of the mobiline peritrichs (from top to bottom) – Semitrichodina , Trichodinella or Tripartiella , Trichodina or Urceolaria , Vauchomia . ( c ) Detail of the oral infraciliature and related structures in the infundibulum of a peritrich. The