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Polybrachykinety : a band-like patch of kinetids arranged in multiple short kineties perpendicular or oblique to the longitudinal axis of the band; especially applied to the oral ciliature of ophryo- scolecids ; see Syncilium . Polyenergid : state of having either multiple nuclei and/or multiple ploidy in a nucleus within a single cell or protistan body; all heterokaryotic ciliates exhibit this condition, generally to a high degree. Polygemmic : production of multiple buds , syn- chronously or consecutively; a mode of fission exhibited by some suctorians and chonotrichs (Fig. 2.11Cc). Polygenomic : synonym for polyploid , with respect to ciliate macronuclei; also used to mean the pres- ence of many non-homologous genomes in the same eukaryotic cell (e.g., nuclear, mitochondrial, chloroplast, bacterial). Polyhymenium : little-used term for denoting the multiple membranelles in the oral region of hetero- trichs and spirotrichs . Polykinetid : a kinetid composed of three or more kinetosomes and their fibrillar associates; see Dikinetid , Dyad , and Monokinetid . Polykinety (pl. Polykineties ): non-prefered term for the oral polykinetids or buccal membranelles of cer- tain groups of ciliates; in peritrichs , the polykinety is essentially an extension of oral polykinetid 1 or peniculus 1 onto the peristome (Pk, Fig. 2.6Ac). Polymerization : postulated evolutionary process of multiplication or increase in usual numbers of some organelle (e.g., in numbers of membranelles comprising an AZM ); may lead to hypertelic devel- opment of certain organelles or structures and may be involved in somatization as well as in auxomor- phy ; see Oligomerization . Polyparakinetal : parakinetal stomatogenesis in which two or more postoral somatic kineties are involved in formation of the oral anlage ; found in many heterotrichs (Fig. 2.11De). Polyphyletic : condition of a taxon being comprised of some members that are descended from or pre- sumed to have been descended from a common Glossary 47 ancestor that is quite different from other mem- bers of that taxon; an undesirable situation to be avoided when building a \u201cnatural\u201d classification; see Monophyletic and Paraphyletic . Polyploid : multiple sets of the haploid chromo- some number within a single nucleus; characteristic of the ciliate macronucleus ; a low polyploid condi- tion may be called oligoploid; see Ampliploid . Polysaprobic : pertains to an aquatic habitat poor in dissolved oxygen and rich in decomposition products, generally including high production of ammonia and hydrogen sulfide; exhibiting a high degree of organic pollution; physicochemically similar to eutrophic ; to be contrasted with mesosaprobic and oligosaprobic habitats that show, respectively, either a medium degree or a low degree of organic pollution; broadly synonymous of polysaprobic are terms such as sapro- pelic and sapropelebiotic; see Saprobity System . Polystichomonad : type of multiple paroral whose infraciliature is composed of more than two paral- lel rows or files of kinetosomes ; found in a few spirotrichs ; see Diplostichomonad . Polystomy : having many or multiple mouths (e.g., suctorians with their typically numerous suctorial tentacles ). Polytomic : division of a single individual into numerous filial products , presumably at one time or in quick succession; generally rare in ciliates, but this type of fission may occur in certain kinds of budding ; see Palintomy . Pore : generalized term for variety of holes or generally small openings into or through the \u201ccell\u201d surface (e.g., plasma membrane, envelopes, pel- licle, loricae, cysts, brood pouch); the contractile vacuole pore may serve as an example of a pore of considerable taxonomic value. Postciliary Fiber : see Postciliary Microtubule . Postciliary Microtubule(s) : singlet, ribbon or band of microtubules associate with Triplet Number 9 of the kinetosome (see Numbering Conventions ), first extending diagonally to the right upward into a pellicular ridge and then \u2013 if well developed \u2013 continuing posteriorly, parallel to and between the kinety containing its kinetosome and the next kinety to the right, with the ribbon either perpen- dicular to or parallel to the pellicle (e.g., postcili- odesma of karyorelicteans and heterotrichs ); in the buccal cavity of many oligohymenophoreans , post- ciliary microtubules are implicated in formation of the ribbed wall (Pc, Figs. 2.1, 2.2). Postciliodesma (pl. Postciliodesmata ): the con- spicuous fiber, running posteriorly on the right side of the associated kinety and composed of stacked ribbons of overlapping postciliary microtubules , and involved in extension of the body following contrac- tion by the myonemes ; a shared-derived character or apomorphy for the classes KARYORELICTEA and HETEROTRICHEA in the subphylum Post cili odesmatophora (Pcd, Fig. 2.2b). Posterior Microtubule : see Postciliary Microtubule . Postoral Meridian : see Postoral Somatic Kinety . Postoral Somatic Kinety (pl. Kineties ): ventral kinety terminating anteriorly at the posterior border of the buccal overture or of the general oral region ; in a number of ciliates, the postoral kinety ( POK ) #1, the rightmost POK if there is more than one, is the \u201cstomatogenic kinety\u201d in parakinetal stoma- togenesis and bears the cytoproct in its left poste- rior extremity as well; particularly characteristic of tetrahymenine hymenostomes (POK, Fig. 2.7f). Postoral Suture : typically, a midventral secant system or line coursing from the oral region toward the posterior pole of the organism and onto which the posterior extremities from both sides converge or run roughly parallel to it; see Preoral Suture (POS, Figs. 2.3h, 2.7h) Prebuccal Area : the depression or oral groove leading to the buccal cavity and lined with somatic or slightly modified somatic ciliature (e.g., in the peniculine Paramecium ); see Vestibulum . Prebuccal Ciliature : the somatic ciliature , more or less modified, lining the oral groove or the preb- uccal area ; formerly termed vestibular ciliature; see Vestibulum . Prehensile Tentacle : non-ingestatory cell exten- sion with pointed rather than knobbed end, found in a few suctorians , such as Ephelota ; allegedly used to capture or hold a prey organism in such a manner as to bring it into contact with the more common suctorial tentacle ; its microtubules are arrayed in a complex arrangement of intercon- nected ribbons (Fig. 2.10g). 48 2. Glossary of Terms and Concepts Useful in Ciliate Systematics Preoral Ciliary Apparatus (pl. Apparati ): all- inclusive term to indicate all categories of oral cili- ature (from atrial to buccal ), differentiating them from somatic ciliature. Preoral Kinety (pl. Kineties ): used for the ante- riormost of the three oral kinetofragments found in certain cyrtophorine phyllopharyngeans ; see Circumoral Kinety . Preoral Suture : typically, a short, midventral line or secant system extending, often to the left, from the oral region to the apical pole of the organism and onto which the anterior ends of a number of somatic kineties from either side may converge (PrS, Figs. 2.3Aa, 2.3Ag, 2.3Ai, 2.4H, 2.4I, 2.7e, 2.7h). Primary Meridian : see Ciliary Meridian . Primary Ribbed Wall : see Ribbed Wall . Primordium (pl. Primordia ): see Anlage . Primordial Field : see Anlage . Priority, Principle of : that the valid name of a taxonomic group is the oldest available name, provided that the name is not invalidated by other provisions of the International Code of Zoological Nomenclature . Proboscis : trunk-like extension of the anterior end of certain ciliates (e.g., Dileptus ); differs from a neck in that the oral region is situated at its base rather than at its distal extremity;