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see also Secant
System . 
Longitudinal Microtubule(s) : a single microtu-
bule or ribbon or band in the pellicle subjacent 
to the plasma membrane , running longitudinally 
down the body between the kineties; found in some 
 oligohymenophorean ciliates. 
Lorica (pl. Loricae ): secreted and/or assembled 
test, envelope, case, shell, or theca; may be calcare-
ous, composed of some proteinaceous or mucopoly-
saccharide secretion, including chitin, pseudochitin, 
or tectin, or made up of foreign matter (e.g., sand 
grains, diatom frustules, coccoliths, debris); found 
most commonly in peritrichs , folliculinids , and tin-
tinnines , with the important properties of fitting the 
body loosely, opening at one (anterior) end (or occa-
sionally both ends), and being either attached to the 
substratum or carried about by the freely-swimming 
organism (e.g., by tintinnines); may occur in a mul-
tiple (arboroid-tree) state; such a “house” or “tube” 
may be occupied only temporarily (e.g., as is true in 
the case of some stichotrichs) (Figs. 2.4S, 2.8A). 
Loricastome : specialized opening or aperture, sur-
rounded by thickened but movable lips, in the rigid 
lorica of lagenophryid peritrichs ; the buccal cilia-
ture may be extended through the aperture when it 
is open, the migratory larval form exits through it, 
and microconjugants can enter through it. 
Lysosome : cytoplasmic organelle bounded by a 
unit membrane and containing hydrolytic enzymes; 
see Golgi Apparatus . 
36 2. Glossary of Terms and Concepts Useful in Ciliate Systematics
Macroconjugant : larger member of a pair in con-
jugation , and the only surviving conjugant in cases 
of total conjugation , such as in peritrichs ; a little-
used synonym is macrogamont . 
Macrogamont : see Gamont , Macroconjuant . 
Macronuclear Anlage (pl. Anlagen ): nucleus that 
begins development from one of the diploid division 
products of the synkaryon and finishes development 
as the typically highly polyploid macronucleus . 
Macronuclear Evolution Hypothesis : origin of 
the complex, nearly autonomous, polyploid macro-
nucleus typical of the great majority of contemporary 
ciliates from a preceding diploid and non-dividing 
form (stage 2), which, in its turn, supposedly arose 
– concomitant with the first micronucleus – from a 
single nucleus (i.e., homokaryotic stage 1), before 
the differentiation that led to nuclear dualism ; appli-
cation of this idea to ciliate systematics is enhanced 
by recognition of the actual existence today of sup-
posed karyological relicts assignable to the first 
two postulated stages as well as to the last, stage 3, 
which is today the predominant condition. 
Macronucleus (pl. Macronuclei ): so-called veg-
etative, trophic or transcriptionally active nucleus; 
controls the organism’s phenotype; may be multi-
ple, but even then is typically much larger than the 
micronucleus ; most often compact, spherical or 
ellipsoidal, but sometimes of diverse other shapes 
(e.g., reniform, moniliform, filiform, dendritic, 
halteriform, C- or E-shaped); typically ampliploid
or polyploid , but diploid or paradiploid in the 
 karyorelicteans , with respect to its genomic con-
tent; commonly contains numerous small nucleoli ; 
may be homomerous or heteromerous ; divides by 
amitosis , though totally incapable of division in 
the karyorelicteans; has regenerative powers, but 
normally is resorbed during sexual phenomena and 
replaced by products of a synkaryon , itself derived 
from fusion of gametic nuclei (Ma, Fig. 2.9Aa, 
2.9Af, 2.12). 
Macrophagous : feeding on relatively large par-
ticles of food; see Algivorous , Carnivorous , and 
Microphagous . 
Macrostome : a stage in the polymorphic life cycle 
in which the oral apparatus undergoes morphogenesis 
to become enlarged and capable of ingesting larger 
prey items, typically other ciliates, and sometimes 
conspecifics; see Microstome (Fig. 2.4B). 
Macrozooid : see Zooid . 
Marginal Cilia : circumferential band of long, stout 
cilia located above the aboral locomotor fringe of 
many mobiline peritrichs ; sometimes called cirri
because of their stoutness. 
Marsupium : see Brood Pouch . 
Maternal Form : see Parental Form . 
Mating Type : a physiological state of the mature 
stage in the clonal life cycle of a ciliate enabling it 
to engage in conjugation with other individuals of 
different or so-called complementary mating type; 
can be developmentally determined either geneti-
cally or epigenetically (e.g., by cytoplasmic factors 
or environmental factors). 
Maxillary Armature : see Capitulum . 
M-band : see Myoneme . 
Meganucleus : see Macronucleus , the preferred 
Membrana Quadripartita : see Quadrulus . 
Membrane : generalized term with a variety of par-
ticular meanings depending on its specific modifier: 
(e.g., see Cystic Membrane, Nuclear Membrane, 
Paroral Membrane, Plasma Membrane , Undulating 
Membrane ); in ciliate systematics, often understood, 
to mean a ciliary membrane, such as the paroral . 
Membranelle : one of the several serially arranged 
oral polykinetids , often known as the adoral zone 
of membranelles ( AZM ) or adoral zone of oral poly-
kinetids (AZOPk), typically found on the left side 
of the buccal cavity or peristomial field ; its cilia , 
sometimes seemingly fused or partially coalesced, 
if only hydrodynamically, may be used in food-getting
or locomotion; the generally rectangular infracili-
ary base is commonly composed of two, three or 
more rows of densely set kinetosomes , which may 
or may not be associated with parasomal sacs and 
may be linked by microtubular or micro fibrillar 
structures in specific patterns not necessarily iden-
tical for each row of the base or for the similar-
appearing “membranelle” in a different taxonomic 
group; membranelle sensu stricto may be used to 
refer to the left-hand oral ciliary organelles of the 
 tetrahymenine hymenostomes ; membranelle sensu
Glossary 37
lato includes organelles very likely not homologous 
(e.g., see Heteromembranelle, Membranoid,
Paramembranelle, Peniculus, Polykinety, and 
Quadrulus ) (M1, M2, M3, Fig. 2.7e). 
Membranoid : an oral polykinetid , including either 
the definitive membranellar fields or some stage 
in their development, in species belonging to the 
 oligohymenophorean scuticociliates ; at one time, 
alpha, beta, gamma and zeta types were differen-
tially defined, the first three referring to the oral 
polykinetids on the left side of the buccal area, 
from anterior to posterior, and the fourth to the 
paroral on the right; the zeta membranoid or paro-
ral in some scuticociliate species may consist of 
three, more or less separable, segments (“a”, “b” 
and “c”), with terminal fragmentation (probably of 
“b”, in this case) into a dozen additional pieces in 
the genus Schizocalyptra and with “a” most anteriad
and “c” (= scutico-vestige ) at the posterior end, 
sometimes far to the left (e.g., in Pleuronema ). 
Meridian : see Ciliary Meridian . 
Merotelokinetal : telokinetal stomatogenesis in 
which the oral anlage is derived by proliferation of 
kinetofragments from a limited number of somatic
kineties ; found in colpodeans , cyrtophorians , and 
 prostomes (Fig. 2.11Db, 2.11Dc). 
Mesocyst : see Cyst . 
Mesosaprobic : see mention under Polysaprobic . 
Metacyst : a “granular layer” between the ciliate cell
surface and the endocyst ; see Cyst . 
M Fibers : see Myoneme . 
Microbiocenosis : restricted natural community 
of interacting microorganisms, including ciliates, 
with a stability of limited duration, but temporary 
equilibrium may be repeatedly regained. 
Microconjugant : smaller member of a pair in 
conjugation ; completely absorbed by the macro-
conjugant in cases of total conjugation (e.g., in 
 chonotrichs and peritrichs ); a little-used synonym is 
Microfibril : generalized term, perhaps better