Cap 2

, tactile cilia, thigmotactic cilia ), 
52 2. Glossary of Terms and Concepts Useful in Ciliate Systematics
the concrement vacuole (and Müller’s vesicle ), 
organelle of Lieberkühn , palps , and the paralabial 
organ . 
Sessile : attached to substrate either by lorica , 
stalk , holdfast , peduncle , or other cell process; see 
Sedentary . 
Seta (pl. Setae ): see Bristle . 
Sexual Phenomenon (pl. Phenomena ): meiosis, 
haploid gametic nuclei , and a diploid synkaryon
are involved; any reproduction that takes place 
occurs at the end of the process and is purely by 
asexual fission ; see Autogamy and Conjugation . 
Sheath : the outer portion of a peritrich stalk; see 
Annulus . 
Shell : preferred term is lorica . 
Sibling Species : one or more biological species
that are difficult, if not impossible, to distinguish 
based on morphological critera; the syngens of the 
Paramecium “aurelia” complex and the Tetrahymena 
“pyriformis” complex are groups of sibling species 
of ciliates. 
Silberliniensystem : see Argyrome . 
Silver-impregnation Techniques : cytological 
staining methods that permit deposition of sil-
ver ions onto argentophilic sites where they are 
reduced, under UV light or appropriate chemicals, 
blackening the coated structures or areas affected 
and thus rendering them beautifully visible under 
subsequent light microscopic examination; the 
argyrome or silverline system so revealed in cili-
ates has proven of immeasurable value in com-
parative taxonomy and morphogenesis; the Klein 
“dry” method and the “wet” methods of von Gelei 
and especially of Chatton and Lwoff show up the 
argyrome sensu stricto , the more or less superficial 
“cortical” structures, such as the silverline merid-
ians , the contractile vacuole pores , the cytoproct , 
and – most importantly – the (general sites of 
the) kinetosomes , both somatic (comprising the 
kineties proper) and oral (e.g., the infraciliary 
bases of the oral or buccal organelles ); other 
methods, especially Bodian’s Protargol (activated 
silver albumose) technique and the Rio-Hortega 
method, additionally blacken many truly cortical 
organelles of the infraciliature sensu lato , deeper in 
the organism, such as the kinetodesmata , the nema-
todesmata , extrusomes , microtubular ribbons , and 
myonemes , and even the nuclei , mitochondria , and 
contractile vacuoles , as well as the cilia them-
selves, thus allowing distinction between ciliferous
and barren kinetosomes (Figs. 2.3, 2.4). 
Silverline System : once popular synonyms are 
Silberliniensystem and neuroformative System; see 
Argyrome . 
Simple Ciliature : general term restricted to mean-
ing individual ciliated monokinetids (e.g., those 
comprising a somatic kinety ) or single isolated 
ciliated monokinetids, such as most bristles , or cili-
ated dikinetids ; excluded are formations or arrange-
ments of cilia that are closely apposed in special 
groups or packets or blocks with some sort of 
interconnection, such as found in the case of cirri , 
somatic polykinetids , syncilia , some atrial and 
vestibular ciliature , and all oral “compound” cili-
ature, such as the paroral , undulating membranes,
polykinetids , and membranelles sensu lato . 
Skeletal Plaques : term recently applied to the 
numerous polysaccharide granules assembled in 
the unique sucker of certain clevelandellid armo-
phoreans . 
Skeletal Plates : term usually reserved for the long 
recognized and generally highly conspicuous sub-
pellicular structures composed of polysaccharide 
reserves (i.e. amylopectin) within a fibrillar lattice; 
found in the entodiniomorphid vestibuliferans 
(i.e., ophryoscolecids and relatives); also used in 
reference to the uniquely calcified cuirass of the 
 prorodontid Coleps (SP, Fig. 2.5Af). 
Skeletal Ring : see Denticulate Ring . 
Skeletogenous Structure : non-specific term usa-
ble for any organelle or system (e.g., various micro-
tubular ribbons , kinetodesmata , nematodesmata , 
various proteinaceous rods, and polysaccharide 
formations, which may lend a certain firmness or 
rigidity to the cortex or to all or part of the body of 
an organism); see Cytoskeleton . 
Solenocyst : dense vesicles found in the tentacles 
and subjacent cytoplasm of the suctorian cell body; 
fusing with the food vacuole membrane as it forms 
at the tentacle tip, they provide membrane and 
presumably contain lytic enzymes that aid in the 
preliminary digestion of the prey as it is ingested. 
Glossary 53
Solitary Form : an individual ciliate; used principally 
in reference to noncolonial forms in a contrasting 
sense; for example, there are colonial and solitary 
 peritrich species, sometimes within a single family. 
Somatic Area : see Somatic Region . 
Somatic Ciliature : all-inclusive term for any cilia
or compound ciliary organelles found anywhere on 
the body outside the oral region ; associated with 
it would be the bases of all such structures, the 
somatic infraciliature ; compare to Oral Ciliature . 
Somatic Infraciliature : see Somatic Ciliature . 
Somatic Kinety (pl. Kineties ): kinety confined to 
the somatic region . 
Somatic-meridional : now discarded term for a 
mode of stomatogenesis ; see Parakinetal . 
Somatic Region : general term for all of a ciliate’s 
body except the oral region ; may be functionally 
subdivided (e.g., thigmotactic area ); its primary 
functions are locomotion, attachment to the sub-
stratum, and maintenance of form. 
Somatization : evolutionary process of increas-
ing the separation of “generative” from “somatic” 
functions in protozoa, demonstrated in ciliates in 
the development of nuclear dualism , in the compli-
cations of sexual phenomena , in the manifestation 
of epigenetic morphogenesis , and in the general 
diversification and differentiation, often involving 
polymerization , of more complex structures and 
functions that approach almost a metazoan level of 
organization. 
Somatogenesis : the replication and development 
of all somatic components of the cell, usually 
occurring during the interfission period, but also at 
fission (e.g., contractile vacuole pores, cytoproct); 
see Stomatogenesis . 
Sorocarp : “fruiting body” developing atop an aerial
stalk after aggregation of cells; found only in the 
 colpodean Sorogena , in which the individual cells 
encyst as a sorocyst, a component of the sorocarp. 
Sorocyst : see Sorocarp . 
Sorogenesis : production of a sorocarp . 
Spasmin : see Spasmoneme . 
Spasmoneme : used to describe the membrane-
bound bundle of contractile protein, predominantly 
spasmin, found in the stalks of various sessiline 
 peritrichs ; arises from and maintains continuity 
with microfilaments in the bell or zooid proper; its 
former structural subdivision into thecoplasm and 
kinoplasm has not been confirmed by electron micro-
scopy; see Myoneme (Sn, Fig. 2.9Bi, 2.9Bj). 
Spherical Colony : zooids dispersed throughout 
a rounded, usually gelatinous but firm, colonial 
mass, with body axes perpendicular to the colony 
surface; because of attachment to a flat substratum, 
the overall shape may more often be hemispherical; 
the framework of such a globular colony may be 
basically arboroid, as shown by some species of the 
 peritrich Ophrydium whose zooids are intercon-
nected by long and slender “penduncular fibers” 
produced by their scopulae (Fig. 2.8Bb). 
Spica : a secant system on the right anterior surface 
of amphileptid pleurostomatids . 
Spindle Trichocyst : see Trichocyst . 
Spines : variously used, though especially for cer-
tain apically located holdfast organelles (e.g., in 
some astomes); also applied to quite elaborately 
developed structures on the outside of the body of a 
number of chonotrichs ; see Attachment Organelle
(Sp, Fig. 2.9Bc–2.9Be). 
Spongiome : see Spongioplasm . 
Spongioplasm : specialized secretory cytoplasm, 
of