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Cap 2


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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;