Introduction

     The terminology used by various authors in describing the morphological features of the foraminiferal test is far from being unified and varies greatly from case to case (compare e.g. Reiss, 1963, Hottinger, 1978, Hottinger et al., 1990, 1993, Loeblich and Tappan, 1964, 1987). The reasons for the variety of terms for the same feature are in most cases not at all formal, but due to differences of opinion with regard to the significance of features, concerning homologies and analogies, to differences in levels of accuracy, as well as due to different methods of observation (Hottinger, 1978).

    The terms listed in the following Glossary, are accompanied [in square brackets] by alternative terms used and (in round brackets) by terms considered to be synonymous, partially synonymous, unclear or for other reasons to be avoided.

    Numbers following the definitions refer to selected Plate/Figures in Hottinger et al.1993 where the respective feature is illustrated.
 
    For comments or suggestions, please fax Professor Lukas Hottinger at 41-61-267 3613.

Glossary

• Abaxial - directed away from or far from  shell axis.
• Aboral - opposite to apertural [oral] end.
• Accessory aperture (infralaminal aperture, auct.) - opening that does not lead directly into the main chamber lumen, but extends beneath accessory structures (e.g. in bullae). 100/7,8.
• Acicular - needle-shaped.
• Acicular spine - see spine.
• Acuminate - tapering, i.e. getting thinner or pointed; conical.
• Acute - shape with acute or sharp angles.
• Adapertural depression (periapertural depression; cavity; apertural fissure, auct.) - space formed by a  toothplate and separated by the latter partly or completely from the main chamber lumen. Interconnected adapertural depressions produce a canal. 115/4. 119/15. 120/7. 124/7.
• Adaxial - directed towards or positioned near the shell axis.
• Advolute chamber arrangement - in spirally coiled forms where chamber lumina in whorl cover laterally those of the preceding whorl to a considerable extent, but not entirely, on one or both sides. Compare: evolute, involute. 2/5,6.
• Acervuline - chambers in irregular, clustered arrangement, as in Acervulina.
• Adauxiliary chamber - chamberlet arising from single radial stolon (additional in respect to apertures between proto- and deuteroconch) in the embryonic wall of orbitoidiform shells. Adventitious - produced by or with the help of foreign particles such as those forming an agglutinated test.
• Agamogony - asexual reproduction within the reproduction cycle, from the first mitotic division of the zygote to meiosis.
• Agamont - specimen grown from the zygote, producing either gamonts or schizonts in an asexual process involving apogamous nuclear divisions and/or meiosis. Foraminiferal agamonts, produced by a sexual reproduction, are microspheric (B - form).
• Agglutinated - shell texture characterized by components gathered in the ambient environment and bound by organic or biomineralized cements produced by the cell. Particles may be selected according to size and shape to form a closefitting mosaic. Often, the agglutination in the external and internal parts of the wall is differentiated without sharp boundaries: external agglutination is finer-grained and better organized than internal parts. 1/1. 12/1. 29/4,10.
• Alar prolongation - winglike extension of umbilico-lateral portions of involute chambers on lateral surfaces of previous whorls in lenticular tests. May be meandering. 182/1. 224/6.
• Allopatric speciation - emergence of species by geographic isolation of populations for sufficient time to alter the genome of the populations involved to mutual reproductive incompatibility.
• Alternation of generations - see life cycle.
• Alveolar layer - layer of alveoles in lateral chamber walls forming diagnostic exoskeletal structures lacking a differentiation of beams and rafters as well as polygonal subepidermal patterns, as in opposition to subepidermal, polygonal networks or keriothecal textures.
• Alveole (alveolus, pl. alveoli) - recess of varying depth coated by the organic lining in lateral chamber walls, blindly ending with a rounded contour below an epiderm or some equivalent outer layer of the wall and opening into the chamber lumen. May be branching towards the outer part of the wall, each generation of branches forming layers within the wall.

    Remarks: The term alveole is used here exclusively for exoskeletal structures, i.e. for subepidermal, tiny compartments of the chamber cavity coated by organic lining. Alveoles must be distinguished from paraporous or keriothecal cavities belonging to the wall texture. The latter are (by definititon) not filled with living chamber plasm nor coated by the organic lining. The simultaneous presence of both alveolar structures and keriothecal wall texture in the fusulinid Verbeekina and its relatives, the combination of an alveolar exoskeleton with a paraporous external wall in Dicyclina or with a bilamellar perforate wall in Fabiania supports a consequent restriction of the term's use to exoskeletal structures, never to textures.
    Layers of alveoles coating the lateral chamber wall are present in various agglutinated groups of which Cyclammina is the most prominent while Everticyclammina is an early extinct representative of an exoskeletal layer of exclusively undivided, shallow alveoles. The Neogene group of Textulariella (GrЪnhagen and Luterbacher, 1966) has branching alveoles. Among the porcelaneous foraminifera, Austrotrillina may be an unique group. In this genus, species with deep and branching alveoles (A. howchini, Adams, 1968) are said to evolve from earlier forms with layers of shallow, undivided alveoles.
    The term alveole is also used for rows of blind recesses in postseptal position over supplementary apertures in the previous septal face as in Subalveolina or Bullalveolina. We do not yet know, how to interpret (in terms of exo- or endoskeletal elements) these alveoles nor what might be their biological meaning.
• Annular arrangement - arrangement of concentric annular chambers. 81/6. 226/3.
• Annular canal - free space between endo- and exoskeletal structures in spirocyclinids.

    Remarks: Unrelated to canal systems in lamellar perforate foraminifera. The term should not be used but replaced by annular space.
• Annular chamber - ring-shaped. May be subdivided. 82/1,4. 226/5. 227/5.
• Annular passage - see preseptal passage.
• Annulus - ring-shaped chamber, wich may be subdivided, or ring-shaped cycle of chamberlets.
• Anterior - directed to or positioned near or on frontal part of chamber, usually enclosing main aperture, distal in respect to direction of growth.
• Antetheca - apertural face in fusulinids.
• Apertural axis - see milioline coiling.
• Apertural chamberlet - cavity in preseptal position below radiate aperture in Lenticulina and related forms. Lamellar nature of septal wall between main chamber and apertural chamberlet unclear.
• Apertural face - surface of chamber-wall comprizing the main cameral aperture.
• Apertural flange - see lip.
• Apertural lip - see lip.
• Apertural plate [basal plate] - a plate-like structure along the base of an interiomarginal aperture and restricting the latter. 147/6,9.
• Apertural tooth - see miliolid tooth and valvular tooth.
• Aperture - primary opening within the test or between test elements, putting into communication intrathalamous with extrathalamous cytoplam. May be single or multiple.  (See cameral aperture; foliar aperture; supplementary aperture; labial aperture).
• Apex - initial portion of trochospiral or conical test.
• Apical - referring to initial part of trochospiral or conical test.
• Apogamy - reproduction process where the offspring has the same number of chromosomes than the parent cell.
• Arborescent - branching growth-pattern in tree-like manner of permanently attached tests. 176/1.
• Areal - aperture and/or intercameral foramen: position of aperture(s) and/or foramina within apertural face, not at its base nor at the shell margin.
• Areal aperture - cameral aperture in distal wall, not at suture. May be single or multiple. 2/14,16. 79/15. 129/6.
• Arenaceous - see agglutinated.
• Areolate - chamber wall subdivided into more or less equal surfaces (areoli) as in Homotrema.175/7,8.
• Astral fissure - see folium, foliar aperture, foliar suture.
• Astral furrow - see foliar suture.
• Astral lobe - see folium.
• Attics (French: mansardes) - outermost lateral or abaxial chamberlet layer in multiple-layered endoskeletal chamber structures of porcelaneous shells distinguished from less lateral or adaxial ones by its comparatively small caliber and its higher number per unit chamber wall surface.
• Autogamy - sexual reproduction process where amoeboid gametes from the same gamont mate (in foraminifera within the mother shell) to form a zygote. May be combined with gamontogamy.
• Auxilliary tunnel - coalescence of several cuniculi as in Polydiexodina.
• Axial filling - secondary deposits in narrow spaces around the axial columella in fusulinids

 and pfenderinids.
• Axial section - slice bisecting test in plane coinciding with axis of coiling and intersecting

 proloculus. 82/1. 75/5. 214/1.
• Axial septulum (in verbeekinid fusulinids) - exoskeletal structural element parallel to septum and consequently corresponding to the rafter in other exoskeletons of agglutinated foraminifera.
• Axis of coiling - imaginary line around which spiral test is coiled.

• Balloon chamber - hemi- to sub-spherical chamber surrounding a float-chamber in the pseudoplanktic stage of some benthic foraminifera; provided with multiple openings for extrusion of gametes. 146/2,3,7.
• Basal - at the base or parallel to the base of a structural element or of the architecture.

    Remarks: The term may be used correctly for apertures or foramina at the base of the apertural face adjacent to the previous whorl (in contrast to areal) or for the base of cone in conical shells including sections in or parallel to cone base. See also basal layer.
• Basal flap - interiomarginal spathulate, more or less excavated infold of distal wall projecting into milioline aperture, restricting the latter. 39/10. 40/4.
• Basal layer - in porcelaneous species: term used for inner portion of the chamber-wall coating the adjacent preceding coil. 75/12,15.
• Basal lobe - a finger-like extension of a chamber wall at the spiral or septal suture (in the absence of an interlocular space). (See retral lobe and compare ponticulus). 109/1. 110/1.
• Basal skeleton - see chomata.
• Beam - exoskeletal main partition of the chamber lumen perpendicular to the chamber septum and to the lateral chamber wall. May fuse with endoskeletal elements such as septula, particularly in verbeekinids, orbitolinids and cuneolinids. May occur as unique exoskeletal element (Orbitopsella) or in combination with minor, shorter exoskeleton elements producing a subepidermal polygonal network.

    Remarks: Davies (1930) distinguished "primary" or "major" (1939) partitions in the description of orbitolinids as in opposition to "secondary" or "minor" elements. Henson (1948) separated subepidermal plates from main partitions (the latter being of endoskeletal nature and therefore to be called septula nowadays; compare Henson's fig. 7). Henson's (1948) subepidermal plates, synonymous with Silvestri's "trabecole perpendicolari" (1932), were subdivided again into "transverse" and "parallel" partitions corresponding to Davies' major and minor elements. Henson's general term "subepidermal partition" may include main partitions (=septula), transverse partitions (= beams) and parallel partitions (= rafters), where septula and beams fuse to produce (mostly radial) chamber compartments.
    In order to clearly separate partitions of exoskeletal from endoskeletal origins Hottinger (1967) introduced particular terms for partitions exclusively of exoskeletal origin, i.e. "poutre" for major and "poutrelle" for minor partitions translated into english in 1978 as "beam" and "rafter" (Balken and BКlkchen in German).
• Biconcave - test having both sides concave (in coiled forms).
• Biconch - megalosphere and deuteroconch separated by a straight septum, different in shape as compared to later, curved ones. Frequent in megalospheric nummulitids where, at the biconch growth stage, the deuteroconch exclusively houses the symbionts (RЪttger, 1974). The uncurved septal wall hints to equal hydrostatic pressure in protoconch and deuteroconch as morphogenetic control prior to calcification of the wall, and hence to a particular growth process during this particular growth step.
• Biconvex - test having both sides convex (in coiled forms).
• Bifid - divided into two branches.
• Biformed - change in chamber arrangement during ontogeny, as from coiled to uncoiled or triserial to bi- or uniserial.
• Bilamellar wall - in perforate foraminifera a chamber wall formed primarily of two mineralized layers (outer and inner lamellae) on both sides of a primary organic sheet. See also lamellar wall; outer lamella; inner lamella; median layer; primary organic membrane or sheet.
• Bilateral - having two equal sides, as reflected by a plane surface.
• Bilocular - said of an embryonic apparatus having two chambers differing in size and shape from following ones.
• Biloculine - see milioline coiling.
• Bipartitor - bridge-like structure, extending posteriorly from an umbilical plate, crossing the preceding aperture and attached to the adjacent coil, thus cutting off the intercameral foramen from the opening into a primary umbilical canal. 137/6-10.
• Biserial - trochospiral chamber arrangement with about 180° between consecutive chambers producing two rows of chambers. 111/11.
• Biumbilicate - spiral test having umbilici on both sides. 102/4. 193/2,3.
• Biumbonate - having an umbo on both sides of the test. See also: umbo.
• Blades - plate-like, strongly protruding, short or long costae. 127/11.
• Boss - round and raised knob-like inflational structure in axial position. Compare: plug; pile. 186/3,10.
• Brood chamber - chamber(s) or chamberlet cycle(s)  with enlarged chamber cavities housing offspring before hatching. The enlarged chamber cavities may be produced by partial resorption of shell material, in particular of endoskeleton and septa. 81/7,8.
• Buccal aperture - see funnel.
• Buccal ring - see chomata.
• Bulla - blister-like test element covering primary, main or supplementary apertures. May have marginal accessory apertures. Present on ultimate chamber of planktic foraminifers only. 100/6-8.
• Calyx (pillar-pore auct.) - funnel-shaped, perforate invagination of lateral wall supporting expanse chambers over a wide area. 175/10. 177/2,3,5.
• Cameral [chamber] aperture - single or multiple opening in chamber-wall putting in communication a main chamber lumen with the exterior and converted partly or entirely  into an intercameral foramen, unless the latter is formed secondarily by resorption. See also supplementary aperture; foliar aperture. 78/8,12. 103/5. 208/4,9. 126/11. 143/1. 157/9.
• Canal systems - term collectively and broadly applied to interconnected spaces of the foraminiferal test, primarily or secondarily separated from the main chamber lumina, but with which they may communicate in the same or in successive whorls by openings other than  intercameral foramina, so-called loop-holes. Canal-systems contain functional  microtubular ectoplasm and represent bypasses of main  chamber lumina in the whorls, directly connecting ectoplasm deep inside the early parts of the test with extrathalamous rhizopodial ectoplasm. The spaces forming canal-systems are delimited by different elements of the test: umbilical plate, cover-plate joined to a foramenal plate, sealing plate, toothplate, septal flap, folia, previous coil, as well as consecutive outer lamellae. See primary and secondary spiral umbilical canals; intraseptal interlocular spaces; grooves; enveloping canals; vertical canals; marginal cord.
• Canaliculate spine - spine- or club-shaped to arborescent radial structure composed of consecutive outer lamellae enclosing canals (supplemental skeleton). May contain spikes. Compare  pseudospine; spine. 199/10.
• Cancellate - having honeycomb-like surface ridges. 106/2.
• Canalicular structure - structural pattern produced by repeated modes of canal disposition in the foraminiferal shell. See also: canal system.
• Carina [keel] - peripheral thickening of shell. In bilamellar foraminifera formed by outer lamella. 17/7. 25/8,10. 147/1.
• Cell envelope in foraminifera - All elements covering the living cell body of a foraminifer delimited by its plasmalemma.
• Central complex - adaxial cone in conical agglutinated forms where radial septula are fused to an irregular pattern of meshes. In contrast to radial and marginal zone.
• Chamber [loculus] - space(s) comprised between skeletal elements of the test and produced at an instar, i.e. during a single growth step. See also: cyclical chamberlets; subsidiary chamberlets; stellar chamberlets; foliar chamberlets.
• Chamber arrangement - disposition pattern of chambers.
• Chamber lobe - see folium.
• Chamber (or chamberlet) lumen - Shell cavity filled with protoplasm (usually of endoplasmic nature except in newly formed chambers) coated by an organic lining as primary cell envelope. Chamber lumina communicate by definition exclusively through intercameral foramina and/or multiple stolon systems. This term is used in particular to distinguish between "inside" and "outside" of the shell, i.e. between intra- and interlocular spaces. The latter are never papered with an organic lining.
• Chamber passage - see passage.
• Chamber wall(s) - skeletal elements formed at one and the same instar, enclosing the corresponding chamber and coated by an inner organic lining.
• Chamberlets - segments or subdivisions of a chamber. See also: subsidiary chamberlets; cyclical chamberlets; foliar chamberlet; stellar chamberlet.
• Chessboard pattern - chamberlet arrangement in superposed chamberlet layers according to an alternating position similar to chessboards: in one layer, the position of the chamberlets corresponds to the one of the black fields, in the following layer to the one of the white fields, as in Sphaerogypsina. Chamberlet outline may be quadratic, polygonal or somewhat irregular. This three-dimensional array corresponds to the planorbulinid, annular chamberlet arrangement in alternating radial position in the second dimension. 173/1,7,9.
• Chirality - proportion of right-hand to left-hand coiling directions in a population of trochospiral organisms.
• Chloroplast - organelle of plant cell (in foraminifera of endosymbiontic algae) responsible for photosynthesis, with ultrastructures diagnostic for the different algal group with their different pigments. See light requirements.
• Chloroplast husbandry - particular symbiotic relationship where chloroplasts of ingested algal food cells are kept in the host protoplasm in a state of partial functionality.
• Choma (pl. chomata; German: Basalreifen) - Dense, textureless deposit on previous whorl constituting the chamber floor, forming a pair of parallel ridges, each extending from a tunnel margin to the previous one, in fusulinids. May extend progressively polewards over the entire chamber floor in staffellids much like a basal layer in fusiform porcelaneous shells.
• Clavate - club-shaped.
• Coalescence - fusion of separate, elongated parts.
• Coil - see whorl.
• Coiling axis - see axis of coiling.
• Compartment - lumen of the shell housing chamber protoplasm, communicating with other lumina in the shell by constricted passage-ways. Supposed to function as a reactor receptacle unit for cell metabolism. Chambers may constitute compartments or be subdivided in chamberlets as compartment units. Compartments may have specific shapes.
• Congeneric - belonging to the same genus.
• Conspecific - belonging to the same species.
• Contrefort - lateral thickening of inner wall layer against base of chamber lumen thinning out or vanishing completely in the equatorial plane, as in some archaediscids. May be homologous to basal layer.
• Convolute - see evolute.
• Corona - first cycle of chamberlets enveloping an embryonal apparatus completely, at least in one plane of sectionning, as in Discocyclina.

    Remarks: The term may be useful in biometry when describing the relation between the diameter of the embryonic apparatus and the number of chamberlets in the immediately following growth stage. See also: periembryonic chamberlets.
• Cosmopolitan - Occuring all over the world where ever there is a suitable habitat.
• Costae - raised ribs or ridges on test surface. See also: striae; blades. 24/17. 120/1.
• Costate - having costae.
• Costellae - particular ornament on chamber wall produced by more or less elongate ridges formed by aligned fusion of pustules by secondary lamellation.

    Remarks: The term was introduced to describe the particular ornament of Costellagerina, a rugoglobigerinid from the late Cretaceous. It might be useful to extend the term for the radial ornamentation of the ventral chamber walls in smaller benthics indicating gamontogamy (pairing of two gamonts venter against venter), as in Corrugatella, Glabratellina etc.. 148/9.
• Counterseptum - kind of lower lip of interiomarginal - basal aperture appearing in appropriate sections as foreward directed hook below the foramen and glued to the previous shell whorl, as in Eulinderina guayabalensis (Nuttall) or Amphistegina lopeztrigoi Palmer.(Butterlin, 1987). The hook is said to develop into complete septal walls in Helicostegina.

    Remarks: The hook may be identical with the gutter in Old World amphisteginids. The nature of the complete, helicosteginid countersepta remains to be analysed the more so as the relation between "countersepta" and stellar septula in the New World amphisteginids are not clear.
• Cover plate [umbilical cover plate] (retroparies, pars auct.) - a more or less folded, imperforate extension of the septal flap into the preceding chamber through the intercameral foramen, cutting off - in the preceding chamber - the main chamber lumen from a foliar chamberlet. Usually attached to a preceding foramenal plate. It is a secondary feature, never present in the ultimate chamber and thus not homologous with a primary foramenal plate or umbilical plate. Compare also: sealing-plate. 141/6. 142/3. 203/11. 205/2. 206/6.
• Cribrate - perforated by multiple holes. Should be used exclusively for numerous and small multiple apertures.
• Cruciform - cross-shaped (aperture).
• Cuneate,cuneiform - wedge-shaped.
• Cuniculus (pl. cuniculi; cunicular passage) - transverse passage at the chamber base, parallel to the tunnel, connecting the lumina of alternating chambers, produced by the fusion of opposed folds in adjacent septa loosing at their point of fusion the contact with the previous  whorl. The geometry of the apertural face in cunicular fusulinid shells remains unclear.
• Cycle of chamberlets - multiple segments of a main chamber lumen, produced at one and the same instar. 157/1 5.
• Cyclical arrangement - arrangement of cyclical chamberlets in one plane or in concentric layers. 157/5,7. 159/4. 173/6.
• Cyclical chamberlet - one of the cyclical segments of the main chamber-lumen produced at one and the same instar. 227/5.
• Cyclopsinellid structure - arrangement of endoskeletal elements as in Cyclopsinella: pattern of arrangement of endoskeletal pillars following the pattern of the radial stolon axes superposed in radial position in neighbouring stolon planes. This particular pattern has the tendancy to produce a more or less complete fusion of the pillars into a median shell wall.
• Cyst - temporary cover enveloping part of the shell, the whole shell or several individuals at once, consisting of adventicious material bound by organic material or slime, for protection of chamber building, for reproduction or by accumulation of refused food particles (feeding cyst).
• Cytoplasm - protoplasm, excluding nucleus.
• Dendritic - see arborescent.
• Deuteroconch - chamber following immediately the proloculus and differing in shape and often in size from subsequently formed chambers. 183/ 1,2.
• Dextral coiling - clockwise direction of coiling as seen from the spiral side.
• Diaphanotheca - light-colored or translucent wall layer immediately below tectum in fusulinids.
• Dimorphism - coexistence of two distinct morphotypes corresponding to different generations in the life cycle of a single species, concerning adult growth stages and/or protoconch and following nepionic chambers. The protoconch diameter is large (megalospheric = A - form) when the agamont's protoplasm is distributed (including eventual symbionts) among the cloned offspring. The protoconch diameter is small (microspheric = B - form) when the gamont's gametes fuse pairwise to form a zygote which does not inherit protoplasm nor symbionts from the mother. If there is dimorphism in the adult shell, the B - form gets larger than the A - form. The initial phases of the B - form having a small volume, they are slow in early growth and therefore selected for life-spans adapting to the low but permanent basic carrying capacity of an oligotrophic warm environment, while the A - form, by its large initial volume, adapt by their rapid growth to spring and eventuel autumn peaks of the carrying capacity. Nepionts with large megalospheres may have a particular architecture different from the adult (see megalospheric apparatus). In complex life cycles, a third (schizontic) generation may produce megalospheric shells with a slightly different morphology than the gamonts. See also: trimorphism. 79/8,9. 228/1,2.
• Distal - farthest from the proloculus in direction of growth.
• Distal chamber wall - farthest, in direction of growth, chamber wall.
• Distal face - outer surface of distal chamber-wall.
• Distinctly radial texture - appearance under crossed nicols of test wall fragment producing a dark cross of interference and concentric colour rings. Corresponds to fibrous ultrastructure.
• Dorsal - the side of a flattened organism turned away from its substrate, as opposed to ventral. See also: spiral side; umbilical side.

    Remarks: Revets (1994) rightly points out that the terms dorsal and ventral, beyond their specific meaning within the architecture of vertebrates, are referring to the orietation of a flattened organism in respect to its substrate. In foraminifera, benthic, free shells are living with their apertural face on their substrate in order to gather food. Permanently attached shells are living with their apertures turned away from the substrate, usually for filter feeding. In most free, trochospiral forms, the spiral side is in dorsal, the umbilical side in ventral position. This may be inversed in permanently attached forms. Therefore, the terms dorsal-ventral and spiral-umbilical respectively are not synonyms, as currently in use.
• Ectoplasm - microtubular outer zone of cytoplasm, forming also the pseudopodia; functions in movement, catching of food, in transport of food, of excretory products and of gametes, in sensory tasks, in gas exchange, as well as in test formation processes.
• Egg-holder structure - Enlarged internal pore-entrance with rims and with or without spinose projections at junction  with adjacent pores. 187/5. 224/7,8. 229/8. See also Hansen and Reiss, 1972, pl.10, fig.2.
• Elongation index - in alveolinids, the ratio of axis length to equatorial diameter.
• Embryon [embryonic apparatus] - group of chambers including proto- and deuteroconch (nucleoconch), in some genera also a flexostyle, and different in size, shape and arrangement from subsequent chambers. 82/8. 170/4. 177/4, 6.
• Embryonic - earliest growth stage in foraminiferal ontogeny, usually distinguished from later stages by an abrupt change in shell architecture, commonly with thickened walls indicating a longer period of standstill in growth (embryonic apparatus) as frequent in the megalospheric generation of larger K-strategists.
• Embryonic pseudochamber (Zwischenkammer in Grell 1954) - hemispherical cavity between deuteroconch and third chamber seen on dorsal side of shell as hemicircular protrusion.

    Remarks: The "true", i.e. lamellar nature of this cavity and its connection with the regular spiral chambers seen in Rotaliellidae (see also Pavlowski 1992) is not yet known.
• Endemist - occuring in restricted geographic areas; as in opposition to cosmopolitan.
• Endoplasm - central part of protoplasm containing nucleus or nuclei and in which the major metabolic processes take place.
• Endoskeleton -  localized thickenings of the chamber wall on its internal surface partly or totally subdividing the main chamber lumen in the lee of protoplasmic streams according to a pattern produced by the arrangement of intercameral foramina in the sequence of successive septa. Plate-like elements (septula), usually perpendicular to the septum, may form more or less complete partitions touching the lateral walls or fusing with elements of the exo-skeleton. Discontinuous, columnar partitions are called pillars (or interseptal pillars). A third type of endoskeleton is produced by shell layers deposited at the chamber floor and coating previously exposed outer shell surface completely (basal layer of miliolids s.l.) or partially (chomata and parachomata of fusulinids). In different taxa, the three endoskeletal types may occur individually or in varying combinations. Often, endoskeletal elements appear only in the course of ontogeny, usually later than exoskeletal elements. Endoskeletal shell elements including the septum in agglutinated foraminifera may be characterized by particularly coarse and irregularly shaped agglutinated particles obscuring the genetic pattern in contrast to the exoskeletal elements of the same specimen

    If the toothplates and their eventual equivalents in lamellar perforate foraminifera or the secondary septa in the orthophragminid lamellar architecture are to be considered homologous equivalents to endoskeletal structures of non-lamellar-imperforate foraminifera remains at present an open question.
    Remarks: The term endoskeleton was introduced by H. DouvillО (1906, p. 593 and 602) in a key paper comparing the anatomy of imperforate fusiform shells, i.e. fusulinids, loftusiids and alveolinids. DouvillО already recognized the close morphological relation between apertural and endoskeletal patterns. In his monograph on alveolinids, M. Reichel (1937) adopted this term to designate the structural elements subdividing the chamber in opposition to a so-called exoskeleton comprising the lateral and frontal chamber walls including the apertural face. The strict correspondance between the distributional pattern of the apertures on the septal face and the patterns produced by the endoskeletal elements (in the particular case of the alveolinids by the septula) were clearly demonstrated by the reconstruction of the shell cavities and their connections through the septum as if they were a cast of the shell cavities (Reichel 1937, fig. 27). These patterns are still used today as diagnostic features for the definition of alveolinid genera.
    Hottinger (1967) modified and extended (1978) DouvillО's term to all structures subdividing the chamber lumen and linked to the patterns of intralocular protoplasmic streaming in opposition to exoskeletal partitions independant by number and direction of such patterns. Thus, the originally descriptive term is complemented with a functional meaning and extended to all corresponding features in imperforate shells. In some lamellar-perforate foraminifera, comparatively rare structures (such as the hollow pillars in Chapmanina) correspond in shape and position to the definition of endoskeletal features. Also, there is no reason to interpret their function in a different way. Thus, such features may be called endoskeletal without hesitation. They might lead the way to clarify, by comparing with true toothplate structures, the significance of the latter.
• Entosolenian tube [endosolen] - tube-like internal skeletal structure extending from aperture in proximal direction. 92/13. 95/7.
• Enveloping canals (intramural cavities, auct.) - more or less tubular spaces parallel with the test surface formed within lateral chamber walls and communicating with intraseptal interlocular spaces. The enveloping canals are produced by (non-adhering) imperforate portions of outer lamellae, also covering partly the intraseptal spaces and folded into these spaces, leaving on both sides of this "flying cover" alternating rows of openings for ectoplasmic flow over grooves in the perforate wall, situated between imperforate inflational ridges. 199/3.
• Ephebic - "adult", i.e. post-nepionic growth stage during which the features characterizing the shell architecture remain constant. The ephebic stage may grade into a later gerontic stage where the architectural features risk to become irregular, or altered to form brood chambers, as often observed in the microspheric generation of larger, complex foraminifera. See also: gerontic stage.
• Epiderm - outermost part of foraminiferal non-lamellar, imperforate chamber wall if differentiated by a particular texture from inner layers.
• Epiembryonic - see subembryonic.
• Epitheca - biomineralized deposits on inner chamber surface in fusulinids, comprizing tectorium and chomata.
• Equator(ial) - peripheral line in median plane, perpendicular to axis of planispiral coiling or radial symmetry in chamber arrangement.
• Equatorial aperture - interiomarginal primary chamber aperture in spiral test, straddling the equatorial periphery. 102/5.
• Equatorial chambers or chamberlets - see main equatorial chamberlets.
• Equatorial section - slice of test in equatorial plane. 75/4,15. 82/4.
• Equitant - uniserial arrangement of chevron-shaped chambers more or less embracing the flanks of the preceeding ones, as in Flabellina.
• Euphotic zone - superficial water layers in which light penetration permits photosynthesis of eucaryotic cells, down to 140 m in transparent water bodies (blue deserts).
• Evolute chamber arrangement - in spirally coiled foraminifera where - due to chamber shape - the chamber lumina in a coil do not laterally cover those of the preceding coil. 137/1. 152/8. 222/3.
• Exoskeleton - localized thickenings of the chamber's outer walls on its internal surface subdividing the chamber lumen into blindly ending compartments and forming geometric patterns which are independant in number and direction from those determined by protoplasmic circulation through foraminal systems. Exoskeletal elements may consist simply of partitions (beams) perpendicular to the septum and to the lateral chamber wall producing simple alcoves, or of a tapestry of alveoles of various kinds coating the internal surface of the outer chamber walls. Two main alveolar types may be distinguished: 1) branched or unbranched alveoles with a blind ending of rounded outline below the external wall surface, the partitions lacking a differentiation in beams and rafters and 2) pidgeon-holes with a blind ending of polygonal outline below an epiderm produced by partitions differentiated in beams and rafters. Exoskeletal elements may be very deep, subdividing the chamber almost completely as in Dictyopsella.

    Remarks: M. Reichel (1937) introduced the term expressis verbis as in opposition to DouvillО's "endoskeleton" for alveolinids, designating the free, outer chamber walls including the frontal wall with its apertures as exoskeletal, all internal partitions (septula, basal layer and chamber floors) as endoskeletal. This concept was supported by an obvious differentiation of the wall texture in the external cover of the chamber walls visible in that time mainly by its particular "behaviour" in the diagenetic process. Nowadays, we know that this particular kind of differentiation in the porcelaneous wall is textural and corresponds to the general differentiation of all lamellar-perforate and non-lamellar walls in inner and outer layers. However, in agglutinated foraminifera, there are often true structural elements "in opposition" (i.e. to be classified in separate categories) to endoskeletal structures in much the same geometric way as Reichel conceived it, carpeting the internal surfaces of the free lateral chamber walls. Thus, the term was conserved but its definition restricted to true structures as opposed to also exclusively structural elements of the endoskeleton (Hottinger 1967, 1978). Therefore, the endoskeleton as conceived here comprises septal structures only when such elements consist of blind-ending recesses carpeting also the lateral chamber walls (Hottingerita) or when more complex structures derive from such a feature (Alveosepta). Banner's "hypodermis" (1966, according to English manuscript) is not synonymous with "exoskeleton" but a general term for all kinds of alveolar layers, including the pidgeon-holes of the polygonal subepidermal network, but as opposed to simpler "pseudalveolar" structures as in Orbignya or Voloskinovella. As the distinction of polygonal networks and alveolar structures is of great taxonomic and stratigraphic importance, we do not recommend the use of the term hypodermis.
• Expanse-chamber (dome-shaped chamber, auct.) - chamber extending over a wide area over a previous chamber and adhering to the latter in a vermiculate or reticulate pattern. 168/3. 171/1. 177/7.
• Extrathalamous - situated outside the test.
• Extraumbilical aperture - interiomarginal primary chamber aperture in enrolled species unconnected with umbilicus. 154/8. 156/2. 184/6.
• Extraumbilical-umbilical aperture - interiomarginal primary chamber aperture extending in enrolled species from umbilicus towards the periphery. 147/2.
• Feathered - along numerous parallel grooves extending in more or less perpendicular direction from sutural furrow or fissure onto shoulders of ventral chamber walls, as in Rotalia. 202/6.
• Fistulose chamberlet (marginal chamberlet; peripheral chamberlet, auct.) - in agglutinated foraminifera the space produced in peripheral or lateral position through separation of part of the chamber from the main chamber-lumen by means of a paraporous partition. May be present in species with solid or with paraporous walls. In the latter case, the partition is in continuation of the paraporous inner wall-layer beneath the outward turning outer, solid layer ("pavement"). 6/12. 7/3,4. 10/3. 18/4.
• Flabelliform - fan-shaped.
• Flexostyle - in porcelaneous foraminifera an eaves-like extension of the proloculus-wall producing a u-shaped in section space over part of the proloculus. 82/8.
• Float-chamber - large hemi- to subspherical chamber characteristic of the pseudoplanktic stage in some benthic foraminifera, facilitating floatation. Occurs inside a so-called balloon chamber. 160/13,6.
• Floor (French: plancher; German: Boden) - Part of endoskeleton: wall parallel to basal layer separating superposed, regular chamberlet layers in alveolinids.

    Remarks: Advance in comparative anatomy of alveolinids and miliolids obliges to distinguish superposed regular layers of chamberlets separated by floors (= planchers, Reichel 1937) as in Praealveolina or Alveolinella from irregular, tubular, supplementary chamberlets present in a thickened basal layer as in Alveolina or Subalveolina. Regular supplementary chamberlets and irregular, tubular chamberlets appear as soon as the fusiform shell reaches specific minimum elongation (Hottinger 1962). In particular the irregular chamberlets of Alveolina start to appear during phylogeny as well as during ontogeny, at first in very low numbers, in shells where polar thickening of the basal layer produced an elongation of 1,4 : 1 of axial versus equatorial shell diameter. The difference between regular and irregular-tubular supplementary chamberlets in the polar region is as diagnostic as all other structural features. When revising the axially compressed relatives of the classical alveolinids, Hammaoui and Fourcade (1973) described the basal layer pierced by tubular supplementary chamberlets as "central thickening". Reichel (1984, fig. 3, p. 530) established the homology of the thickened basal layer in the polar area of Subalveolina with the "central thickening" of Rhapydionia. Chubbina was described by Robinson (1968) as having tubular passages in a basal layer, while De Castro established (1990) Pseudochubbina as taxon for a compressed alveolinid "with floors". Looking at the published illustrations, the Chubbina endoskeleton resembles rather the one of advanced Praealveolina with floors while the one of Pseudochubbina has, particularly in adult growth stages, very irregular tubular passages in a massive basal layer. Thus, the unfortunate current use of the term floor is synonymous with basal layer. A detailed structural analysis of laterally compressed alveolinids (Fleury and Fourcade 1990) will be necessary to clearly separate the two kinds of endoskeleton.
• Flosculinisation - Conspicuous thickening of the basal layer in the equatorial zone of miliolid and alveolinid shells.

    Remarks: The term originates as derivation from the ancient generic name Flosculina Stache by Schwager 1883. It occurs not only in alveolinids but in other, unrelated porcellaneous genera as well. Flosculinisation may be restricted to a particular period of the ontogenesis, eventually in two successive portions, and be combined with polar thickening of the basal layer in coinciding or not coinciding ontogenetic stages of accelerated growth.
• Fluting (septal fluting) -  folding of the septa at their base in fusiform shells, as in fusulinids. The folds in consecutive septa are opposing each other and may fuse at their base, loosing contact with the previous shell whorl forming the chamber floor and producing thus a passage way. See also: cuniculi.
• Foliar aperture (labial aperture, pars auct.) - primary opening of a folium to the exterior in interiomarginal anterior, posterior or umbilical (axial) position at the folium borders; between main chamber wall and folium (foliar slit; astral fissure); or within the folium  itself. A foliar aperture may be in continuation of the primary cameral aperture or separated from it, but is never converted into an intercameral foramen. It may  lead to vertical canals  when covered by secondary lamellae. 180/3,4,6. 203/10. 209/1,3.
• Foliar chamberlet - part of chamber delimited by a folium. A foliar chamberlet may be continuous with the main chamber, separated primarily (and partly or more completely) from the latter by a foramenal plate, by an umbilical plate, or - secondarily - by a cover plate or a sealing plate. A foliar chamberlet communicates with the exterior through foliar apertures and with its own main chamber lumen through openings in the umbilical plate or cover-plate (wherever present) or at its margin. Depending upon geometry of the test elements, a foliar chamberlet may be converted into part of a secondary spiral umbilical canal as part of the umbilical cavity and communicating with intraseptal interlocular spaces.  141/12,13. 180/3. 203/10. 208/4.
• Folium (lip; tenon; umbilical flap; astral lobe, pars auct.) - in spiral lamellar foraminifera the mostly triangular in outline and often texturally differentiated (porosity) axial-umbilical portion of the lateral chamber wall. The border between main lateral chamber wall and folium may be indicated by a short, posterior  indentation or "notch" or by an umbilical plate-suture. An opening (foliar aperture) is always present between the anterior margin of a folium and the adjacent previous coil. In addition, umbilical and/or posterior openings may be present, depending upon whether the folia are free or attached by their tips or along their posterior margin. In some genera such as Asterorotalia, folia may extend onto the preceding chamber and be attached to it, covering partly intraseptal interlocular spaces, wherever present. A folium is composed of the same layers as those forming the main chamber wall. See also: foliar chamberlet; foliar aperture. 143/3. 144/1. 146/5. 150/3. 203/10. 209/3.
• Foramen, foramina [intercameral] - opening or openings putting in communication consecutive main chamber lumina and providing passage for functional endoplasm. May be primary, hence formed by an initial cameral aperture, or secondary, i.e. formed by resorption of parts of the septum. Cameral apertures converted into intercameral foramina may be modified in shape by resorption or through restriction by attachment of toothplate, foramenal plate or umbilical plate. See also: stolon. 97/8. 123/12. 137/7. 193/5. 201/12. 217/4. 220/1.
• Foramenal axis - axis common to two or more intercameral foramina or stolons in subsequent septa.
• Foramenal disposition - pattern generated by regular spacial disposition of foramina on septal faces.
• Foramenal plate (toothplate; paries proximus, pars auct.) - basically a primary infold or "inpush" in the direction of growth of the posterio-lateral chamber wall at a sutural notch, and attached to an intercameral foramen. A foramenal plate may be a short finger- or lobe-like closed structure, a short straight plate, a marginally open plate, folded at an angle to the axis of coiling and attached to the adjacent previous coil, or tunnel like and reaching a spiral opening. A foramenal plate partly separates a main chamber lumen from a foliar chamberlet and is in continuation of a septal flap. It may or may not be connected with a cover plate, which separates - in the preceding chamber - completely the  main chamber lumen from a foliar chamberlet. Compare: umbilical plate; cover plate; bipartitor. 141/6,12. 143/3. 201/12. 203/11. 205/2,3.
• Fore-court - deuteroconch with multiple apertures covering the outer flexostyle opening and parts or all of the megalosphere wall in complex soritid embryos. Introduced by Lehmann (1961) under the German term "Vorhof". 82/8.
• Fossette - opening to the exterior of an intraseptal interlocular space which is subdivided by ponticuli with retral processes. 213/8. 214/6.
• Four-stolon system (or pattern) - pattern of stolon arrangement in cycles of arcuate chamberlets alternating in radial position from one cycle to the next and connected by 2 oblique stolons to the preceding and by 2 to the following cycle.
• Foveolate - see pits, pitted.
• Funnel - see vertical canals.
• Fusiform - shell shape in form of a spindle produced by planispiral-involute growth where the axial diameter is larger than the equatorial diameter and where the polar ends of the shell are tapered.
• Gametogamy - sexual reproduction process where gamonts release their flagellate gametes into the free water column, where they mate.
• Gamogony - sexual reproduction within the reproduction cycle, from meiosis to fecundation generating the zygote.
• Gamont - specimen producing gametes in the process of reproduction irrespective of its involvment in meiosis (diploid gamonts) or not (haploid gamonts). Foraminiferal gamonts, produced by asexual reproduction, are megalospheric (A - form).
• Gamontogamy - sexual reproduction process where two gamonts form a nuptial cyst in which, under protection, the amoeboid gametes from the two gamonts may mate.
• Gerontic (growth stage) - ultimate growth stage distinguished from ephebic (adult) growth stages by a reduction of growth rates and usually many structural irregularities.
• Global community maturation (GCM) - gradual change of community composition by evolutionary and coevolutionary processes in a global ecological realm such as a climatic belt around the globe and its subdivisions such as a photic zone within the tropics. The time period governing a GCM unit is of geological dimensions. Disrupting geological events which produce the boundaries of the larger time units in the geological time scale often delimit GCM cycles.
• Granular texture - see jagged granular and mosaic granular texture.
• Groove - elongated depression produced by external local thinning of outer lamella. Becoming deepened by persisting thin secondary lamination and concurrent thickening of adjacent inflational costae or ridges usually present. Leading mostly into intraseptal interlocular spaces and often running on periphery (marginal cord) or on lateral walls parallel to outline of chamber periphery (e.g. chevron shaped pattern producing feathering). Grooves may be partly closed by secondary lamination in later growth stages and transformed into canals. 199/3.
• Gutter - in Amphisteginidae: free end of an umbilical plate, folded anteriorly at an angle to the axis of coiling.  (Compare foramenal plate). 188/6.
• Hamulus - see tooth. This term has been coined for endothyrids.
• Hemiseptula - in Amphisteginidae infolds of the inner lamella partially subdividing a chamber. 183/3. 190/3,6.
• Hemiseptular suture - line of adherence of hemiseptula to lateral wall. 183/3,4.
• Hispid - covered with minute pustules or pseudospines. 100/7.
• Husband, husbandry - see chloroplast husbandry.
• Hypodermis - exoskeletal structures below an epiderm. See: polygonal network; alveoles.
• Imperforate - lacking pores or parapores.
• Incisional ornamentation - pattern of primarily thinned portions of outer lamella deepened by secondary thin lamination, usually adjacent to inflational ornaments. See also: grooves.
• Index of elongation - see elongation index.
• Indistinctly radial texture - appearance under crossed nicols of test fragment producing extinction in the center of the fragment with other extinctions irregularly distributed. Corresponds to bundle shaped ultrastructure.
• Inflational ornamentation - pattern of primarily thickened, often imperforate areas of outer lamella becoming additionally thickened by secondary lamination. See also: pustules; pseudospines; costae; carina.
• Inflational pillar - see pile.
• Inframarginal sulcus - see infundibulum.
• Infundibulum [inframarginal sulcus] (scrobis septalis, pars auct.) - distinct proximally directed infold of distal chamber wall in interiomarginal position beneath periphery, on the umbilical side of trochospiral forms. See also: marginal prolongation. 147/2. 196/2,9.
• Inner lamella (inner lining, inner calcareous layer, pars auct.) - in bilamellar foraminifera the inner mineralized part of the primary chamber wall between inner organic lining and primary organic sheet. Built mainly of stacked calcitic platelets or of aragonitic prisms. In calcitic foraminifera it comprises also the inner array of large, paired rhombic crystals formed initially on both sides of the primary organic sheet and included by some authors in the so-called "median layer".
• Inner organic lining (IOL) - see organic lining.
• Instar - a single stage in the discontinuous growth process of most foraminifera reflected by the formation of a chamber of the shell (or of a cycle of chamberlets). See also: chamber; chamberlet cycle; lamellation.

    Remarks: The use of this term in foraminiferology is contested, mainly by biologists. The Cambridge Dictionary of Biology (Walker ed. 1988) defines instar as "the form assumed by an insect during a particular (ontogenic) stadium" (such as pupa, imago etc.). Others have used the term for each segment of life-time in between subsequent periods of ecdysis (moulting) of marine arthropods. Transferred to foraminifera, the formal definition would mean rather growth stages commonly designated as embryonic, nepionic or ephebic characterized each by a succession of several or numerous chambers. However, since each growth-step does change the form of the shell and can be individually identified in each specimen by counting the number of chambers, starting with the proloculus, to the respective instar, I see no reason to reject the already traditional and most convenient use of this term as substitute for the term chamber including however also such parts of the shell produced by the same growth-step that do not enclose a chamber lumen, such as the respective outer lamella in bilamellar shells, participating in the construction of umbilical, inflational plugs, piles or in umbos and enveloping all exposed surfaces of the previously formed lamellar shell.
• Interauxiliary chamber(s) - periembrionic chambers lacking direct communication with embryo lumen, as part of periembryonic spirals, as in Miogypsina.
• Intercameral foramen - see foramen.
• Interio-areal aperture - aperture situated in distal wall near its base, but not at the suture with preceding coil. See also: areal aperture. 2/7,8.
• Interiomarginal aperture - aperture situated at suture between distal wall and preceding coil. 102/4,6. 143/1. 147/2. 156/8.
• Interlamellar organic sheets - sheets of organic material occurring between consecutive secondary outer lamellae.
• Interlocular space (lacuna, pars auct.) - a space formed as a consequence of a deeply sunken suture between consecutive chamber walls or between consecutive coils.  (See intraseptal and spiral interlocular spaces). 199/8,9. 203/10,11. 209/6. 219/5,6. 225/5,6.
• Interpore ridges - the external residual or built-up test material in areas between large pores. 104/10. 106/2.
• Interradius (pl. interadii) - in orbitoidiform architecture: sector of undifferentiated equatorial layer in between radii.
• Interseptal - located between subsequent septa.
• Interseptal pillars - in porcelaneous and agglutinated species: the multiple columnar projections of inner wall portion between septum and distal chamber-wall, parallel to protoplasmic flow.
• Intradermal plate - see beam; septulum. Should not be used to avoid ambiguous interpretations.
• Intraseptal interlocular space - in forms possessing a partly non-adhering septal flap, the interlocular space formed between posterior bilamellar wall of a chamber and the distal bilamellar wall of the preceding chamber as a result of a deeply sunken suture. Intraseptal spaces may be open to the exterior along their margins either continuously or through openings between points of marginal adherence of consecutive lateral chamber walls See also: sutural canals; fossettes. 199/8-10. 203/10-11. 209/5,6. 219/5,6. 225/6.
• Intraseptular space - space formed in the wall (septulum)  between adjacent subsidiary chamberlets of the same instar, produced by lateral infolding of the chamber wall. May contain canals communicating with intraseptal canal system. 227/3,4,8.
• Intrathalamous - situated inside the test.
• Intraumbilical - see umbilical.
• Involute chamber arrangement - in spirally coiled forms where - due to chamber shape - the chamber lumina in a coil cover laterally those of the preceding coil. 137/3. 154/7. 214/1.
• Isodiscodine - see biconch.
• Jagged-granular texture - appearance under crossed nicols of test wall fragment showing minutely granulated, irregularly shaped sutured crystals, usually with a more or less uniform yellowish polarisation colour. Corresponds to intricate ultrastructure.
• Joist - see beam.
• Juvenarium - see nepiont.
• Keriotheca - alveolar, honeycomblike structure of spiral wall in advanced fusulinids, may consist of an upper (outer) and a lower (inner) "layer" produced by a split of the alveoli into narrower subunits below the tectum. May be combined  in highly specialized forms with additional exoskeletal structures.
• Knob - see boss.
• Labial aperture - see foliar aperture.
• Labyrinthic - spacial disposition of chamber cavities without any regularity, not producing any pattern.
• Labyrinthic - irregular wall textures or shell structures. Term indicating non-comprehension of features observed. Should not be used.
• Lamellar wall - test-wall built of layers of calcite or aragonite formed at consecutive instars and covering exposed surfaces of previously formed test. Wall generally possessing true pores. Most lamellar genera are bilamellar and some primarily multilamellar. 186/9,10. 214/2.
• Lamelliform buttress - see beam if exoskeletal or septulum if endoskeletal.

    Remarks: Henson (1948) introduced this term for chamber partitions leaning against free outer (mostly lateral) walls as suggested by the meaning of the term in architecture. Buttress is by and large synonym to subepidermal partition. Hottinger (1967) showed the distinction of endo- and exoskeletal structural elements to be of taxonomic and phylogenetic relevance and redefined therefore particular terms for each category of partitions. There is no reason to keep up the use of the term buttress. Where a neutral and purely descriptive term may be helpful in a case difficult to interpret, it is sufficient to speak about "partitions".
• Lamination, lamellation, [secondary lamination] - layering of test-walls due to superposition of consecutively deposited outer lamellae. See also: lamellar wall.
• Lateral canals - see sutural canals.
• Lateral chamber wall - main chamber wall never converted into part of a septum; more or less clearly separated from the chamber periphery or peripheral wall.
• Lateral chamberlets - in orbitoidiform architecture: chamberlets of roughly isometric or irregular to vermicular outline covering in a so-called chessboard-pattern layer-wise both  lateral surfaces of orbitoidiform shells, connected with the main chamberlet layer and between themselves in successive layers by oblique stolons.
• Lateral openings - gap for intracameral communication in neoschwagerinid septula, at the junction of exoskeleton and endoskeleton and, hence, homologous to the lateral passages in anchispirocyclinids. See also: passage.
• Latero-marginal aperture - primary aperture situated on lateral umbilical wall of coiled test, in subperipheral position. 98/1, 2.
• Life cycle - most eucariotic, free-living cells reproduce asexually but shift from time to time to sexual reproduction in order to avoid degeneration (Muller's ratchet, 1932). In many foraminifera, the alternation of sexually and asexually produced generations is documented in the morphology of the shell by dimorphism or trimorphism (see: gamont, schizont, megalospheric generation, agamont and microspheric generation). In foraminifera, there are many different life-cycles (Lee et al.1991). They differ in particular by the emplacement of the nuclear reduction division within the cycle. Planktic foraminifera are interpreted as reproducing exclusively by sexual processes. See also: alternation of generations.
• Limbate - referring to thickened border of chamber-edge at suture; may be elevated. 137/1,3. 147/1.
• Lip [apertural lip] - everted extension of chamber wall along cameral aperture. May be narrow or broad (flange), small or large. See also: phialine lip; rim. Compare: folium. 182/11. 203/9. 206/9.
• Loculus - chamber.
• Loop-hole - small connections between chamber lumen and interlocular space. May be located at periphery (leading into sulcus in nummulitids), at the base of the chamber, as in elphidiids, or in front or in back of umbilical plates or cover plates, as in rotaliids.

    Remarks: The "septal passage" of Parvati (1971) is a loop-hole in pre- or post-septal position. As the term "passage" is reserved for connections between cavities of the same chamber (or instar), the term "septal passage" leads to confusion and is substituted here by pre- or post-septal loop-hole. Loop-holes function as backdoors for the extrusion of ectoplasm when the chamberplasm retracts to inner chambers during a perturbation in the ambient environment.
• Lumen - see chamber (or chamberlet) lumen.
• Maerl - coarse-grained sediment, characterized by components consisting of shells and other skeletal debris, forming extended carpets on the sea floor where the components may be bound by living algal filaments and/or coralline red algal crusts, and consequently resisting to considerable velocities of bottom currents. May be inhabited by normally epiphytic larger foraminifera.
• Main chamber lumen - complete or segmented chamber cavity  communicating with the preceding and succeeding main chamber lumina through (primary or secondary) intercameral foramina. In certain lamellar foraminifera separated partly or completely from a foliar or stellar chamberlet, as well as from canal systems by a foramenal plate, toothplate, umbilical plate, cover plate, or sealing-plate, or by infolded inner lamella or lateral wall producing septula.
• Main chamber wall - test wall enclosing a main chamber lumen. In most lamellar foraminifera composed in its distal and lateral portions of inner and outer lamellae with a primary organic sheet inbetween. In some genera also including a proximal wall composed of inner lamella only (septal flap) covering a preceding septal face. The main chamber wall may also include - wherever present - a foramenal plate, a cover plate or an umbilical plate. In porcelaneous tests (with or without an agglutinated outer layer) the main chamber wall may include an extension of the inner (always porcelaneous) wall portion coating the adjacent chamber (so-called floor). In all foraminiferal tests an inner organic lining coates the main chamber wall.
• Main chamberlet layer - in orbitoidiform architecture: usually annular cycles of chamberlets in the median (equatorial) plane of the shell distinguished from lateral chamberlet layer (if present) by their larger volume and more regular structure. The last cycle of main chamberlets bears the apertural face of the shell.
• Main partition - in Orbitolina: (radial) septulum.
• Marginal apertures - single row of apertures on the shell margin, distinct from areal multiple apertures by their oblique-radial direction, as in Tertiary conical agglutinated forms or in Marginopora. Single marginal apertures in lamellar-perforates, as in almaenids, may be closed by secondary lamellation already in the penultimate chamber.
• Marginal canal system - enveloping canals grouped at shell periphery, often radially extended, as in Pseudosiderolites, and in contrast to marginal cords, where the peripheral direction of the canals is emphasized.

    Remarks: Hottinger 1978 used this term as synonymous with marginal cord. It seems preferable now to distinguish between predominantly radial and peripheral systems. The latter are never modified to include canaliculate spines.
• Marginal chamberlet - see fistulose chamberlet.
• Marginal cord - peripheral system of numerous longitudinal anastomosing grooves and adjacent imperforate elongated ridges and islands of inflational ornament type. Grooves are closed by secondary lamination and transformed into an anastomosing bundle of peripheral tubular canals.  224/3, 1-8. 225/1.
• Marginal prolongation (tectum) - distally directed prolongation of the spiro-marginal portion of a chamber in a trochospiral test, leading the spiral sutures to be much more inclined on the spiral side than on the umbilical one. 137/2.

    Remarks: This feature has also been called tectum, a term preoccupied in fusulinids by the outermost layer of the chamber wall in the chamber roof. The term tectum is therefore no acceptable alternative to "marginal prolongation".
• Marginal zone - marginal parts of discoidal or annular chamber in conical shells or distal-lateral parts of annular chambers in discoidal-evolute shells, often housing an exoskeleton, usually separated from central respectively equatorial parts of the chamber by a furrow on the apertural face resulting a recess of the marginal zone for third or half of the chamber height (in the direction of growth).
• Marginoporid structure - arrangement of endoskeletal elements in space as in extant Marginopora: apertural axes oblique in respect to radial direction, overcrossing in neighbouring stolon planes and alternating in radial position from one stolon plane to the following. Endoskeleton may consist of septula or pillars.
• Mask - mineralized test element(s) obstructing a primary cameral aperture, resorbed in subsequent growth stages. 75/17. 195/3,12. 224/2
• Meandrine - tortuous, winding path of linear features, in particular septal sutures of long alar prolongations, as in Nummulites and Meandropsina.
• Median layer - in bilamellar foraminifera term applied to both the spongy primary organic sheet and the, often present, distinctly larger crystals formed initially in vesicles and occurring paired on both sides of the primary organic sheet. See also: primary organic sheet; outer lamella; inner lamella.
• Median section - slice in central sagittal position normal to the axis of coiling.
• Megalosphere - large sized proloculus in di- or trimorphic species as characteristic for the generation of gamonts and schizonts and in contrast to the microsphere of the agamont. See also: alternation of generations.
• Megalospheric - in dimorphic species: test having a large proloculus or megalosphere; commonly a gamont or schizont.
• Microgranular - wall texture: wall composed of calcareous elements, possibly produced by the cell, of granular appearence in the light microscope but more stable and resistant to diagenetic recrystalization as composed to porcelaneous walls. In fusulinids and pfenderinids, the microgranular wall never encases agglutinated grains, in mesozoic imperforates, agglutinated textures may be substituted by exclusively microgranular material if no grains are available in the ambient environment.
• Microsphere - small sized proloculus of agamont in di- or trimorphic species, in contrast to the megalosphere of the gamonts and schizonts. See also: alternation of generations.
• Microspheric - in dimorphic species: test having a small proloculus or microsphere; commonly a schizont.
• Microstriae - minute longitudinal, usually anastomosing ridges on surface of porcelaneous test. Mostly visible under high magnification, especially SEM. 27/9. 34/8. 35/10.
• Milioline - referring to taxa or their characters of the suborder Miliolina.
• Milioline coiling - in porcelaneous foraminifera: bilocular coils where all terminal apertures are positioned on a single common axis (apertural axis); with coiling axis normal to apertural axis, and rotating in such a manner that between the median planes of consecutive chambers various angles  are produced, e.g.72° (quinqueloculine), 120° (triloculine) or 180° (spiroloculine or biloculine)  or that chambers are positioned in an s-shaped curve in one plane as seen in section (sigmoiline). See also: streptospiral. 30/6. 32/9. 39/9. 46/5,9. 64/6.
• Milioline tooth/teeth - one or more inward projections of the inner portion of chamber-wall into the aperture of milioline species. May be bar-like, spatulate, bifid, or anvil-, T-, Y-, anchor-, spur-, scoop- or spoon-shaped. A single tooth always present primarily in interiomarginal position; may be accompanied by additional teeth projecting from opposite margin of aperture from chamber roof or lateral wall. See also: trematophore. 26/9,14. 29/2,3. 30/5. 51/7,10.
• Monolamellar - lamellar-perforate wall consisting of outer lamella only, lacking median layer and inner lamella. The outer lamella may cover the exposed parts of earlier formed shell completely or partially.
• Monothalamous (unilocular) - shell consisting of a single chamber.
• Mosaic granular texture - appearance under crossed nicols of test wall fragment showing large sutured calcite crystals with finely serrated margins. Corresponds to clumpy ultrastructure.
• Murus reflectus - see umbilical plate.
• Neanic - postnepionic growth stage with adult shell architecture. May be synonym to adult growth stage or designate early parts of the adult stage, without possibility of a clear dilimitation to later adult stages. Should not be used.
• Neck - tubiform extension of ultimate chamber bearing aperture in terminal position, as in uvigerinids.
• Nepionic - juvenile stage following an embryonic and forerunning an ephebic stage.
• Nepiont - growth-stage following the embryonic stage and different in architecture from the adult stage.
• Nonlamellar - chamber walls lacking lamellar texture, as in most agglutinating and porcelaneous forms.
• Notch - indentation in sutural position; may extend into an internal infold. See also: foramenal plate. 139/1. 143/5. 204/9. 206/3,9.
• Nucleoconch - see embryonic apparatus.
• Oblique section - slice through test cut in direction neither parallel to axis, nor normal to it.
• Odd pairs or associations - frequent associations of two or more foraminiferal species exhibiting an identical or a closely related architecture in their adult growth stage but having strikingly different adult size. In most cases, the adult size difference is matched by corresponding, size-dependant architectural features of the megalospheric embryo, i.e. an embryonal apparatus in large forms, a simple, more or less undifferentiated megalosphere in the odd partner.The latter usually are restricted in number to one or two species. An example of a recent odd pair is the frequent association of Amphisorus hemprichii with the odd partner Sorites orbiculus living in the same habitat but reproducing at different times in the seasonal cycle (Hottinger, 1998).
• Odd partner - the small-sized representative(s) of an odd association.
• Oral - apertural.
• Orbitoid architecture - chamber arrangement as in orbitoids s.l., i.e. annular series of chamberlets forming a sagittal, equatorial main chamberlet layer covered on both lateral surfaces by lateral chamberlets.
• Orbitoid growth - chamber arrangement as in main chamber layer of Orbitoides, i.e. single layer of annular series of chamberlets alternating in radial position in successive annular series, each chamberlet communicating in crosswise-oblique direction with its neighbour in the previous and the following annuli.
• Orbitoidal chamber arrangement - see cyclical chamber arrangement.
• Orbitolinid structure - arrangement of endoskeletal and exoskeletal elements in space as in orbitolinids. This term may be used in a larger conception meaning all kinds of structural types occurring in uniserial-conical shells as corresponding to the doubtelessly artificial family Orbitolinidae or as restricted term meaning the particular type of endoskeleton characteristic for Orbitolina and some of its closest generic relatives; i.e. radial subdivision of the discoidal chambers by septula fusing with an exoskeletal polygonal network, where the septula adjust to radial rows of apertures with crosswise oblique stolon axes.
• Orbitolitid structure - arrangement of endoskeletal elements as in Orbitolites: apertural axes oblique in respect to radial direction, overcrossing and superposed in radial position in neighbouring stolon planes. So far, only septular (i.e. continuous) endoskeletal elements are known to follow the orbitolitid pattern of stolon axes. The orbitolinid structure is essentially the same as the orbitolitid structure, but produces a radial structure within a discoidal chamber while the orbitolitid structure produces a subdivsion of an annular chamber.
• Orbitopsellid structure - arrangement of endoskeletal elements as in Orbitopsella: pattern of arrangement of endoskeletal pillars following the pattern of the radial stolon axes alternating in radial position from one stolon plane to the next.
• Organic Lining - organic cell envelope said to consist of mucopolysaccharides, located between plasmalemma and biomineralized cell envelope, covering the protoplasmic cell body in the chamber lumina and in the connecting cavities inbetween them (foramina, stolons), but never in interlocular spaces. May be discontinuous or extremly thin over pore mouths and/or in ultimate and penultimate chambers, usually thickening towards earlier growth stages. May be involved in stolon plugging. May be resorbed together with the biomineralized wall when brood chambers are formed. The organic lining resists dissolution of the biomineralized shell by acidic attack and keeps up the shape of the protoplasmic body capable of remineralizing its shell after the return of normal conditions in the ambient environment. However, the role of the organic lining in biomineralization has to be investigated in future.

    Remarks: There is no reason to abandon the traditional designation of organic lining (as used by Loeblich and Tappan, 1987) in favour of "inner organic lining" (IOL) as introduced by Anderson and BО, 1978. The eventual use of an "outer organic layer" called for by the IOL and possibly applied either to the outer organic cover of the biomineralized shell or to the temporary organic envelope protecting in some species the chamber formation process would rather add confusion in the description of the numerous layers of the cell envelope and their specific functions.
    Moreover, the term "inner organic lining" gets easily confused with the term "inner lining" which is equal to "inner lamella" and corresponds to the inner calcified lamella of the primary wall in perforate foraminifera.
• Orifice - unspecified opening in the test such as apertures or canal system mouths. It is proposed here to restrict the term to a strictly functional meaning, i.e. to openings where protoplasm extrudes from the shell.
• Ornamentation - patterns of external modification of wall thickness and/or texture. See inflational ornamentation; incisional ornamentation; textural ornamentation.
• Outer lamella - outer mineralized layer of primary wall in bilamellar foraminifera, external to the primary organic sheet. It comprises at its base the outer array of distinctly larger paired crystals at the primary organic sheet (and included by some authors in the "median layer"), the stacks of calcite platelets or pseudohexagonal aragonite prisms forming the major part of the outer lamella, as well as the outermost thin layer of blocky columnar crystals forming the so-called veneer.

• Parachomata - Chomata supplementing the primary pair of ridges in the equatorial zone of the shell laterally and polewards, regularely intercalated between supplementary tunnels until the polar end of the chamber as in Pseudodoliolina. May fuse with the beams of an exoskeleton in order to form complete partitions in the chamber, as in Neoschwagerinids.
• Parafossette - opening between bifurcating ponticuli and chamber wall margin of preceding chamber, communicating with intraseptal interlocular space and fossettes. 213/7,8. 214/6. 215/4.
• Parapores (canaliculi; pseudopores, pars auct.) - in agglutinated foraminifera: straight to tortuous tubular spaces, round to polygonal in section, more or less normal to test surface, coated and closed off internally by organic lining. May be branching and anastomosing and - usually - restricted to the inner wall-layer, thus ending blindly beneath an outer solid "pavement". No sieve-plate present. Parapores may be laterally interconnected. They may lead into irregular cavities or fistulose chamberlets between paraporous wall-layer and pavement. The partition between main chamber lumen and fistulose chamberlet, wherever present, is always paraporous. Compare: pores; pits. 8/11. 10/9,10. 17/1,9. 21/7.
• Paries proximus - integrative term designating the proximal, septal chamber wall and the various extensions produced independently by the inner lamella at the chamber bottom or at its adaxial umbilical region, including also structures in the previous chamber such as umbilical coverplates.

    Remarks: this term was introduced  by Levy et al. (1979, p.68) in order to support the revision of discorbid foraminifera. It integrates the following terms presently in use: septal flap, proximal wall, foraminiferal plate, coverplate and umbilical plate. It is a partial equivalent of Hofker's (1951) tooth plate. The term is too broad to be helpful in distinguishing the various structures diagnostic for different genera in various families as was Hofker's idea to place all ("tooth"-) plate-bearing taxa into a common group, the foraminifera dentata. The nevertheless most important paper of Levy et al. (1979) constitutes the basis of Loeblich and Tappan's conception of the Discorbidae (1987) in present-day systematics.
• Partitional pore(s) - see passage(s).
• Passage - communication between adjacent chamber compartments of the same chamber; may be positioned below frontal chamber wall (preseptal), after septal wall (postseptal) as in alveolinids, or at fusion between exoskeleton and endoskeleton, as in verbeekinids. In peneropliform to concentric architectures, passages may be semiannular-annular, in preseptal position, as in Sorites, or pair-wise in lateral position, separating exoskeleton from endoskeleton, as in Anchispirocyclina.
• Pavement - in agglutinated foraminifera the outer solid wall layer covering an inner paraporous layer. 9/9. 10/3,10.
• Penultimate chamber - chamber before the last formed in an individual.
• Perforate - referring usually to wall possessing true pores, but term also applied to wall possessing parapores.
• Perforation pattern - distribution pattern of external pore mouths on lamellar shell surface, combined with  or totally disconnected from the ornamentation of the shell.
• Periapertural depression - see adapertural depression.
• Periembryonic chamberlets (periembryonic cells, corona) - all chamberlets immediately surrounding an embryonic apparatus. In orbitoidiform architecture restricted to equatorial main chamberlet layer and used in context with the term chamber. In orbitolinids: the forth chamber constituting an annulus covering the margins of deuteroconch and subembryonic chamber. This is the first chamber subdivided by an endoskeleton in orbitolinid ontogeny.

    Remarks: Introduced by Douglas 1960, this term originally designated all parts of the third growth stage including subembryonic chambers, without analyzing in detail the complicated structures of this part of the test. Today, much weight is given to the distinction between periembryonic and subembryonic chambers. (Schroeder 1962, Arnaud-Vanneau 1980).
    The term is unclear because it may comprise more than one cycle of chamberlets in one group, a unique cycle in the other. We recommend to use instead the term corona, but only when the first cycle of chamberlets covers the embryo completely in at least the equatorial plane, as in Discocyclina. See also: auxiliary chamber, adauxiliary chamberlets.
• Peripheral chamberlet - see fistulose chamberlet.
• Peristome [peristomal lip, peristomal rim] - raised rim or tube around aperture or foramen. 1/12. 48/4. 65/5. 78/7. 160/2. 163/6.
• Phialine lip - lip on apertural neck. 127/7. 128/10.
• Photoinhibition - diminishing rates of photosynthesis under stronger irradiation than necessary for optimal rates.
• Phrenotheca - Thin, calcified partitions irregularly dividing the chambers in various directions, as in Pseudofusulina.
• Pil intradermal plate - see beam.
• Pile (inflational pillar auct.) - superposed lamellar thickenings (pustules) on lateral walls or folia in consecutive whorls or consecutive chamberlet layers, producing a pillar-like structure. Compare: interseptal pillar. 205/1. 211/8. 220/4,5,6.
• Pillar - see interseptal pillar; pile.
• Pillar - pore - see calyx.
• Pioneering - early stage of community maturation starting from a totally or almost empty habitat invaded by immigrants specialized for rapidly occupying empty spaces with their unused resources. See also: community maturation.
• Pits (pseudopores; punctuations, pars. auct.) - in porcelaneous foraminifera, as well as in spirillinid and in some unilocular genera: rounded to oval in section, tubular to conical, externally open spaces, directed normal or oblique to the test surface, penetrating to different depths of the wall in different genera and sometimes arranged in several tiers; in many cases anastomosing and thus resembling parapores of agglutinated foraminifera. The term "pitted wall" is often applied to the test texture of planktic, non-spinose foraminifera possessing distinct external pore-funnels or "pore-pits". 43/7,8. 45/8,9. 73/6,10. 78/8,10. 80/7.
• Planispiral chamber arrangement - arrangement in whorls where the rate of translation (net rate of movement along the growth axis to the net rate of movement away from the axis) is zero. Spiral and umbilical sides of the test identical and symmetrical with regard to plane of bilateral symmetry. 75/1. 77/2. 108/3. 214/1. 220/3.
• Plastogamic plate - plate-like structure covering umbilicus in plastogamic specimens of some benthic foraminifera. 117/6,11.
• Plastogamy - fusion of adults by umbilical surface at time of sexual reproduction.
• Plate suture - line of adherence of umbilical plate to lateral wall. 180/4. 182/10. 190/5.
• Plectogyral - see streptospiral.
• Plug [umbilical plug] - expanding pile of thickened lamellae in axial position in an umbilicus or in an umbilical bowl. May be single, compound and/or canaliculate. 199/4. 201/4. 208/1,2.
• Pole of shell - point where tips of involute chambers in a planispiral whorl meet the axis of coiling, in subspherical to fusiform shells. See also: polar torsion.
• Polygonal subepidermal network - exoskeletal structure formed by layers of always undivided, deep, tubular recesses in chamber walls, blindly ending below a thin, often transparent epiderm or similar structure, generating a polygonal pattern at their distal end and opening into the chamber lumen by slightly restricting mouths with a rounded outline between partitions of the chamber differentiated in beams and rafters.

    Remarks: In foraminifera with much inflated chambers such as Bradyina or Gyroconulina, the beams may produce a polygonal pattern of their own rather than form a row of main partitions perpendicular to the septum.
    Introduced by H. DouvillО in 1901 under the name "rОseau sous-epidermique", the term was used mainly in the description of orbitolinids where Davies distinguished already in 1930 major and minor partitions. In the later anglosaxon literature, these details were not considered as important: Cox (1937) described the Loftusia exoskeleton as "alveolar layer" and Henson (1947) preferred to use the general term "subepidermal partition" for all elements subdividing the chamber lumen into "pidgeon-holes" or "subepidermal cells". The general term "subepidermal partition" was extended by Henson himself and by later authors to any kind of lateral chamber partition depriving the term of any significance for comparative or functional anatomy. For this reason, we recommend to drop the use of the term "subepidermal partition". Henson's term "pidgeon-holes" rather than "subepidermal cells" would be appropriate to distinguish these from ordinary alveoles or alcoves.
    A polygonal network has not been found in any extant foraminifer. Therefore, a coating of the recesses by the organic lining can not be directly confirmed. The argument to interpret the polygonal network as exoskeletal structure and not as a particular kind of wall texture (as pointed out by Henson (1947 already) is their combined presence in many keriotheca-bearing fusulinids or in the pore-bearing Fabiania and its relatives. The extremely thin, often transparent epiderm in agglutinated foraminifera suggests, that the polygonal network is a device to keep symbionts exposed to light and in the immediate vicinity of the location where gaz exchange through the shell may be enhanced by particular, porous textures.
    It may be of taxonomical importance at supra-generic level to distinguish at least two different kinds of polygonal networks. The first one to appear in the Mesozoic, with Haurania and Amijiella of Middle Liassic age, is comparatively coarse and deep. There is probably no clear differentiation of an epiderm, just a thin outer wall covering the polygonal ends of the blind recesses. The differentiation of beams and rafters does not seem to be very orderly, even in evolute, fan-shaped to discoidal shells such as Timidonella or Alzonella. The second group, arising not much later in Pseudocyclammina liasica, has finer meshes and a clearly differentiated, extremely thin epiderm. It characterizes most late Mesozoic conical foraminifera as well as the peneropliform spirocyclinids.
The question arises, if there are evolutionary series of exoskeletons from simple to complex, such as Praekurnubia (Late Middle Jurassic) with simple beams as exoskeleton, Kurnubia (Early Upper Jurassic) with a comparatively simple polygonal network, and Rectokurnubia (Late Upper Jurassic) with a deep and more complex polygonal network. Similar evolutionary trends were also described in reticulinellids and in conical agglutinated foraminifera. No series of such exoskeletal structural complication has been observed in the ontogeny in any of the numerous genera involved. So far, the question remains unsolved in my view (for discussion see Hottinger 1978, table 1, p. 255).
• Ponticulus, pl. ponticuli - bridge of lateral wall spanning an intraseptal interlocular space. It may be massive or hollow, in this latter case covering a retral chamber process. Compare: basal lobe; retral lobe; fossette. 208/10. 215/4. 217/1.
• Polar torsion - helicoidal torsion of septa and septal sutures at the poles of fusiform larger foraminifera (mainly in fusulinids and elongate alveolinids), usually linked to polar multiplication of apertures.
• Polythalamous (multithalamous, multilocular) - shell consisting of numerous chambers.
• Polyvalent individuals (polyvalent tests, twins or triplets) - individuals with two or more megalospheric embryos belonging probably to the same clone, with common late growth stage. Accidental association not related to gamontogamy.
• Porcelaneous test wall - composed of optically cryptocrystalline lathes and rods or needles of calcite. Rods arranged randomly, lathes arranged in a tile-roof pattern and forming the outer wall-layer. Wall imperforate, but may possess pits. 29/14. 31/4. 55/17. 69/10. 72/8.
• Pore - minute tubular perforation traversing chamber wall, being internally coated by an organic lining. Subdivided by a pore-plate and closed off internally by the inner organic lining. External and internal size and shape of pore openings may be identical (rounded to elongated) or different. Compare: parapores; pits. 111/2. 114/12. 120/12. 135/10. 181/5,6. 225/3,4,7.
• Pore-chimney - enlarged pore-cavity in secondarily laminated wall, grouping together 2-4 smaller pores of the primary chamber wall. 178/5,7.
• Pore-fields - local concentrations of pores in certain areas of the perforate wall. 139/2,3.
• Pore-funnel [pore-pit] - external enlarged outlet of a pore (in planktic foraminifera). 104/10. 107/9.
• Pore pit - funnel-shaped depression in external shell wall enlarging external pore mouth, in planktonic foraminifera. See also: pits.
• Pore-plate [pore sieve-plate] - minute, microperforated, more or less calcified disk located in the pore tubulus at the level of the primary organic sheet and of a distinct constriction.
• Pore plug - organic structure plugging pore funnel, produced by coalescence of organic cell envelope and organic median layer over the pore lumen. May be partially calcified by minutely perforated platelets called sieve plate.
• Preseptal passage (preseptal canal, annular passage auct.) - in porcelaneous foraminifera, an elongate, undivided space beneath part of septal wall containing the apertures, in an otherwise subdivided by septula chamber. Delimited against the chamberlets between septula by the distal indentation of the latter. 75/9,15. 82/2.
• Primary - belonging to the last formed, i.e. ultimate chamber.
• Primary aperture - see main cameral aperture; supplementary aperture; accessory aperture; stolon.
• Primary chamber - see chamber.
• Primary foramen - see aperture.
• Primary organic membrane - see primary organic sheet.
• Primary organic membrane, POM - see median layer.

Remarks: This term (BО et al. 1980, Anderson and Lee 1991) is misleading and should not be used at all in foraminiferology for the following reasons: The median layer is part of an outer, biomineralized cell envelope and has nothing in common with the primary cell membrane (plasmalemma) of the foraminifer; neither their biochemistry nor their geometry are comparable (see Hottinger and Dreher 1974, Leutenegger 1977). Moreover, the corresponding acronym in POM is used in oceanography for "particulate organic matter" in the water column. Foraminiferal organic linings or its fragments are known to be one of many composants of the particulate organic matter, in particular below the lysocline. This may entail confusion.
• Primary organic sheet (primary organic membrane auct.) - sheet of spongy organic material between outer and inner lamellae in bilamellar foraminifera. In calcitic foraminifera, the primary organic sheet is usually bounded by rhombic, paired crystals which are different from the stacks of platelets forming the major part of the mineralized layers and which have been included by some authors in the so-called median layer.
• Primary plates - in orbitolinids: see exoskeleton. The term comprises beams and rafters.
• Primary spiral-umbilical canal - more or less tubular or flattened space comprized between umbilical plates and the wall of the preceding adjacent coil or between plates, folia and preceding coil; or between toothplates and preceding coil; present in the ultimate chamber. 137/7. 210/2. 224/5.
• Progressive chamber - chamber with a supplementary, retrovert aperture giving rise to a supplementary series of chambers (in architectural types with multiple spirals or in orbitoidiform growth following spiral nepionts.
• Proloculus - initial chamber of foraminiferal test in all generations.
• Protheca - free chamber wall of fusulinids composed of tectum and diaphanotheca.
• Protoconch - first chamber of test in which a deuteroconch is differentiated. See proloculus. 82/8.
• Protoforamen - aperture or intercameral foramen to which a toothplate is attatched.
• Protoplasm - living matter comprizing cell-body.
• Protopore - comparatively narrow pores or parapores believed to represent early phylogenetic features.
• Proximal - nearer to the proloculus, opposite to the direction of growth.
• Proximal [posterior] chamber wall - wall separating a chamber from the preceding one, formed by a septal flap or by a basal layer, or (in part) by a strongly inflected  lateral wall producing with the distal wall of the preceding chamber an intraseptal space.
• Pseudopodia - semipermanent or temporary extrathalamous  ectoplasmic projections.
• Pseudopore - see parapore, pit.
• Pseudorbitoid layer - see marginal canal system.
• Pseudospine (murica; spine, pars auct.) - a pointed conical, or elongated spine-like, usually solid, but sometimes hollow, inflational ornament feature. Compare: spine; acicular spine; canaliculate spine. 88/11. 100/11. 111/9. 112/2. 127/7. 129/1. 172/6. 220/4,6.
• Pseudospinose - possessing pseudospines.
• Pseudoumbilicus (false umbilicus, pars.auct.) - externally visible, extra-axial, narrow or wide, cup-shaped space between infolded distal wall below main cameral aperture and adjacent coil, mimicking an umbilicus. Usually leading into an uncovered spiral umbilical canal. Compare: umbilicus; umbilical bowl; umbilical depression. 137/6,7,10.
• Punctate (punctuation) - see pits.
• Pustule [tubercle; papilla] - hemispherical to subconical inflational protuberance of the outer lamella. See also: pseudospine. 148/3. 157/2,10. 186/11. 194/7. 211/14.

• Quinqueloculine - see milioline coiling.

• Radial - direction from pole or axis to any part of circumference of the test.
• Radial texture - see distinctly radial, indistinctly radial texture.
• Radiate aperture - single aperture, in terminal or margino-terminal position, with radially directed, slitlike or pointed extensions. The radial aperture margins may fuse and thereby subdivide the aperture, as in some nodosariaceans.
• Radius (pl.radii) - in orbitoidiform architecture: radial differentiation of equatorial layer, often producing a stellar periphery of the test, usually by multiplication of the equatorial element in perpendicular direction to the equatorial plane.
• Rafter - Exoskeletal minor partition of the chamber lumen parallel to the chamber septum and perpendicular to beams and lateral chamber wall. Produces subepidermal polygonal network together with beams.

Remarks: The term rafter is a translation into english of DouvillО's term "poutrelle" (1906) restricted here however to minor elements, the major ones being called "poutres" in french (or beams in english). DouvillО did not distinguish major and minor partitions in his "rОseau polygonal" or polygonal subepidermal network at that time.
• Rectilinear chamber arrangement - growth in a straight line.
• Reniform - kidney-shaped.
• Reticulate - having ornamental features arranged in a network. See: cancellate. 109/1.
• Retral lobes - finger-like, hollow extensions of the proximal chamber-wall (in the absence of an interlocular space). See also: ponticuli; retral processes; basal lobes. 187/1,2.
• Retral processes - finger-like proximally directed extensions of chamber lumen covered by ponticuli present at the margins of an intraseptal interlocular space. 210/2,3. 211/6. 216/9,10.
• Retrovert foramen - second, primary foramen located at the base of the marginal chamber suture, opening in proximal direction and giving rise to orbitoidal growth after a spiral nepionic stage or to multiple spirals.
• Reversed trochoid chamber arrangement - trochospiral arrangement with the spiral side more involute than the umbilical one.
• Rhizopodia - bifurcating and anastomosing pseudopodia.
• Rim [peristomal rim] - thickened margin of an aperture. See also: lip. 83/13. 143/1. 155/4.

• Saddle - the distally directed, u-shaped embayment between retral lobes.
• Sagittal section - slice through test normal to axis of coiling and passing through proloculus.
• Salients - rudiments of septa left over after excavation of cuniculi (in fusulinids).
• Sarcode - see protoplasm.
• Schizont - apogamic offspring of an agamont reproducing either by again apogamous nuclear divisions and cytotomy (i.e. by distributing the mother protoplasm among the offspring) or undergoing meiosis. Foraminiferal schizonts, produced by asexual reproduction, are megalospheric (A - form).
• Scrobis septalis - see infundibulum.
• Sealing plate (sealing-off plate; cover plate, pars auct.) - a thin plate, secondarily plugging the opening in an umbilical plate which - primarily - puts into communication a main chamber lumen with a foliar chamberlet. Never present in the ultimate chamber. Compare: cover plate. 210/1,6.
• Secondary - belonging to the penultimate or earlier chambers if different from the last one.
• Secondary apertures - see supplementary apertures.
• Secondary lamination - see lamination.
• Secondary passage - see interseptal, interlocular space.
• Secondary septum - see septulum.
• Secondary septulum - in neoschwagerinids: see rafter.
• Secondary spiral umbilical canal - tubular to flattened space comprized between cover plates and the lateral wall of the adjoining previous coil. 205/3,5.
• Septal face - surface of chamber-wall to be converted into a septum at subsequent instar.
• Septal filaments - sutures of alar chamber extensions   in involute nummulitids, often meandrine.
• Septal flap (paries proximus, pars auct.) - part of the inner lamella covering the preceding septal face. A septal flap may be adhering to the preceding septal face producing in this case a trilamellar septum in primarily bilamellar foraminifera; it may be separated in part from the preceding septal face along a deeply sunken suture, and thus covered by outer lamella, producing an intraseptal interlocular space. The latter may be partial and marginal only on one or both sides of the test or complete. The septal flap may extend into an umbilical plate, a foramenal plate, a bipartitor, a cover plate or a toothplate. 180/11. 203/10,11. 227/3.
• Septal fluting - see fluting.
• Septal foramen - see intercameral foramen.
• Septal passage - in rotaliids: communication between main chamber lumen and spiral canal near septum. See also: loop-hole.
• Septal pore -  primary multiple apertures of small size and irregularly distributed on apertural face (antetheca) of fusulinids.
• Septal suture - suture corresponding to septum.
• Septular suture - suture corresponding to septulum. 82/10.
• Septulum - a skeletal partition extending from the lateral wall between adjacent subsidiary or cyclical chamberlets. In lamellar species produced by folded  inner lamella or by folded bilamellar wall, in porcelaneous ones by inner portion of chamber-wall. 75/6,15. 227/4,5.
• Septulum (French: cloisonette) - Endoskeletal, not interrupted, wall-like partition extending from the lateral wall into the chamber lumen subdividing the latter into compartments. In lamellar-perforate species, the septula are produced by folded inner lamellas while in non-lamellar imperforate forms, the inner portion of the primary wall is thickened. Remarks: In describing alveolinid structures, there has never been any difficulty to distinguish between septum (closing off a chamber) and septulum (partitioning the chamber into chamberlets) since Carpenter (1862), DouvillО (1906) and Reichel (1937). In orbitolinids however, there is considerable confusion. Carpenter (1862) described "Patellina" lenticularis with a "large chamber layer". The latter term corresponds in modern terminology to a single, discoidal (or annular) chamber separated from the next "layer" by a septum. Rolf SchrЪder kept up the idea of the chamber layer up to at least 1973 and abandoned it in his 1985 paper. The concept of a chamber layer in orbitolinids leads to the interpretation of the orbitolinid radial partition as "septum" and of secondary, exoskeletal partitions as "septulum" which is inconsistent with all other imperforate foraminifera. In French papers, where the orbitolinid mode of growth was correctly recognized as an uniserial stack of chambers, we find the simultaneous use of septum (for the true septum), cloison for (endoskeletal) radial main partitions and cloisonette (for beams in the exoskeleton).
• Septum - wall separating two consecutive main chamber lumina.
• Septum (French: cloison) - portion of the free chamber wall that is covered by subsequent chambers and thus incorporated in the architecture of the shell as partition between successive main chamber lumina representing compartments within the living cell body. The connection between the latter are guaranteed by a single or multiple openings in the septum (intercameral foramina, stolon systems). In the case of simultaneous formation of multiple chamberlets, the septum may consist of multiple separate portions acting as partitions between the lumina of successive chamberlet cycles (not of neighbouring chamberlets).
• Sere (or series) - complete sequence of biocoenoses in a succession, from pioneering stages to climax.
• Sessile - permanently attached, usually with attachment surface on dorsal (spiral) side of trochospiral shells. Designates also sedentary life habit.
• Sieve plate - calcified disk with minute perforations closing the pore in continuation with the median layer between primary inner and outer lamellas.
• Sigmoid - s-shaped.
• Sigmoiline - see milioline coiling.
• Sinistral coiling - counterclockwise direction of coiling as viewed from the spiral side.
• Sipho - term broadly applied both to strongly folded buliminid toothplates and to entosolenian tubes.  128/9.
• Six - stolon system - each equatorial ogival or spatulate chamberlet is connected to its adjacent chamberlets in the same cycle by annular stolons and to the neighbouring two chamberlets in the following and in the previous cycle by oblique stolons. The pattern may be duplicated or multiplied in successive stolon planes parallel to the equatorial plane.
• Skeleton - all structural elements shaping the protoplast permanently, in addition to primary chamber walls and chamber septa. The three basic skeletal types, endoskeleton, exoskeleton and supplemental skeleton, may occur in all possible combinations to determine, together with chamber shape and chamber arrangement, the architecture of the shell. The term should not be used as synonym for test and shell designating the total biomineralized cell envelope.
• Socculus (pl. socculi) - low reliefs on basal layer in porcelaneous foraminifera, not touching chamber roof. May form pedestal-like base of pillars and low ridges in between them, on previous apertural face, (as in archaiasinids or soritids) or well developed ridges on basal layer, eventually supporting pillars (as in lacazinids). A socculus is an endoskeletal feature. It has to be distinguished from ornamental elements at the chamber surface of previous whorls covered by a chamber lumen of the next whorl, such as the plugs or ridges on the apertural face in Amphistegina.
• Sphaeroconch - spherical deuteroconch enveloping a thin-walled megalosphere of an embryonic apparatus in agglutinated larger foraminifera. May possess an exoskeleton, never an endoskeleton.
• Spicular wall - test composed of (secreted) fusiform calcite spicules. 85/3.
• Spike - minute, conical to elongate spine-like projection on external wall surfaces of lamellar foraminifera, not thickened by secondary lamination. Spikes occur often on walls of interlocular spaces, as in larger elphidiids, to fend off larger particles such as diatom frustules transported with the food into the canal system by the pseudopods. 206/10.
• Spine [acicular spine] - thin, round, triangular to triradiate in section, calcite rod normal to the test surface, running through a hole in the outer lamella of planktic foraminifera. Originates apparently from primary organic sheet. At its exterior base a spine is surrounded by a more or less conical mound, the spine base. 102/8. 103/8. 108/6,7.
• Spine-base - see spine.
• Spinose - possessing true, acicular spines (in planktic foraminifera). See also: pseudospinose.
• Spiral aperture - interiomarginal aperture along spiral suture. Usually supplementary, not converted into a foramen. 152/8. 154/5.
• Spiral canals - see primary and secondary umbilical spiral canals.
• Spiral fissure - deep, umbilical suture separating ventral chamber tips or folia from an umbilical plug, as in Ammonia.
• Spiral interlocular space - space formed between adjacent coils along deeply sunken spiral suture. See also: intraseptal interlocular space. 198/3,5,6.
• Spiral side - that side of the test in trochospiral forms which comprises the proloculus or towards which the proloculus is displaced. See also: dorsal.
• Spiral suture - suture corresponding to wall between adjacent whorls.
• Spiroconvex - trochspiral shell with convex spiral and flattened to concave umbilical side.
• Spiroloculine - see milioline coiling.
• Spirotheca - free outer wall of fusiform larger foraminifera, in particular of fusulinids, constituting the chamber roof and forming a spiral in equatorial section. Deposits on the chamber floor (tectorium, basal layer) are often included in the term.
• Stellar chamberlet - umbilical closed segment of the chamber separated from the main chamber lumen by an umbilical plate composed of folded inner lamella. Communicates with its own main chamber lumen through a gap between plate and adjacent coil and with the preceding chamberlet through the umbilical part of the preceding aperture, subdivided by posterior attachment of the umbilical plate. 182/3. 183/6. 187/4.
• Stellate - star-shaped.
• Stolon - tubular openings in chamber wall whose length is greater than its diameter, forming cameral apertures and putting in communication consecutive chambers (intercameral foramina), or cyclical chamberlets, and subsidiary chamberlets belonging to the same instar. 227/5,7,8. 229/4,5.
• Stolon plane - plane defined by regularly arranged in layers stolons roughly parallel to equatorial plane.
• Streptospiral arrangement - coiled in successively changing planes, like a ball of twine. See also: milioline coiling. 75/15.
• Striae - thin costae. 126/1-3.
• Striate - having striae.
• Structure - of foraminiferal shells: three-dimensional design shaping chamber cavities as patterns repeated in successive chambers or chamberlet cycles.

Remarks: It is recommended to use the term "structure" in a very precise and somewhat restricted way, i.e. in opposition to wall textures, patterns unrelated to shape of chamber lumina, as well as to shell architecture, term combining structural design and chamber shape and arrangement to a complex, highly diagnostic set of patterns.
• Style - massive, imperforate columnar structure between lateral walls supporting expanse chambers extending over a wide area. 175/6,8,10.
• Subembryonic chamberlets - mono- or plurilocular third growth stage in megalospheric embryos of agglutinated conical foraminifera, located below the proloculus in the conie axis, subdivided by structural elements of dubious, probably exoskeletal origin.

Remarks: J. Hofker jun. (1963, p. 211, fig. 14) interpreted the life habit of an orbitolinid face upward, i. e. cone apex downward, buried in the sediment. Therefore, he called the third growth-stage in Orbitolina sstr. epiembryonic.  The confusion up-down is complicated by a supposed error in the legend of fig. 2 in J. Hofker jun. 1966, where deuteroconch and epiembryonic chambers are exchanged by comparison with his 1963 paper. Today, all foraminifera with an extensive apertural face covered by numerous apertures are living with their apertural face towards their substrate. Doubtlessly, the same was true for the conical foraminifera in general. The term epiembryonic is therefore to be avoided. Douglas (1960) did not distinguish between sub- and periembryonic chambers, both representing the third growth stage. See also: periembryonic and supraembryonic.
• Subepidermal partition (-plates, -lamellae) - unspecified, descriptive terms for any kind of structural element subdividing external (lateral) parts of chamber lumen. May be of exoskeletal (beams and rafters) or endoskeletal (septula) nature.
• Subsidiary chamberlets (secondary chamberlets, auct.) - subdivisions of main chamber lumen by folded inner lamella with primary organic sheet between folds, or by septula. See also: stellar chamberlets. 75/6. 82/4. 228/4.
• Succession (ecological succession) - gradual change in time, over the same surface, of community composition by processes of interspecific competition and coexistence, from the arrival of pioneers in an empty habitat to a mature, equilibrated community composition climax in equilibrium with the environmental conditions. Periodical disturbances in the environment may delimit the succession to early phases of the process (disclimax).
• Sulcus - peripheral infold of primary chamber-wall, always imperforate. May or may not have radial passages between underlying sulcus canal and chamber-lumen. May or may not be covered by marginal structures, like e.g. marginal cord. 225/1,3.
• Supplemental foramen - orifice produced by a strongly folded toothplate within the protoforamen. May be completely closed off from the latter, as in Siphogenerinoides.
• Supplemental skeleton - shell structure produced exclusively by the deformation of outer lamellae covering or enclosing interlocular spaces. As far as known today, the supplemental skeleton is usually not perforate; its cavities never contain  an organic lining. In recent foraminifera, these cavities are filled with ectoplasm.

Remarks: Introduced by Carpenter (1862) long before lamellar theory, and refined here, the term is a wellcome complement to the terms exoskeleton and endoskeleton. The latter both subdivide chamber lumen while the supplemental skeleton structurizes extralocular, "outer" space. It is meant to be used as generic term regrouping all canaliferous marginal and pseudospinose structures as in Siderolites, Pellatispira, Calcarina and their allies as well as all types of marginal cords (linked to a single  sulcus) as in Sulcoperculina and their derivatives, Ranikothalia and all nummulitids sstr.
• Supplementary aperture(s) (secondary aperture(s), pars. auct.) - primarily formed openings either in apertural face ("apertural pores") or (slit-like) in sutural position, always in addition to a main cameral aperture.  Sutural supplementary apertures are not converted into intercameral foramina because of their position and thus apparently do not serve for passage of functional endoplasm between chambers. The same seems to be true of multiple supplementary apertures, which although  situated in the septum, may be absent in earlier chambers and may be plugged in part at a subsequent instar. See also: accessory apertures. 103/4. 137/5. 147/3. 152/8. 156/2. 158/3.
• Supraembryonic area - circular area at shell apex in advanced orbitolinids formed by subdivided annular deuteroconch above the megalosphere. Accordingly the annular deuteroconch are also called supraembryonic chamberlets.
• Supraembryonic (chamber) - more or less hemispherical deuteroconch in apical position, embracing an often in completely calcified protoconch from above, bearing exoskeletal elements, as in Orbitolina sstr. (see Arnaud-Vanneau 1980)

    Remarks: This term was introduced by Douglas (1960) together with the term "periembryonic" for the third (and partially forth) growth stage, below the proloculus, implicitly admitting a life position face downward. Schroeder 1962, 1973 and later Arnaud-Vanneau 1980 attributed much phylogenetic weight to a distinction between supra- and periembryonic chambers.
• Sutural canals - openings to the exterior of an intraseptal space whose margins are partly closed by local adherence of consecutive chamber walls. See also: fossettes. 225/6,7.
• Sutural supplementary apertures - apertures in addition to primary apertures, in ventral or dorsal sutural position, not transformed into an intercameral foramen at the next instar. See also: supplementary apertures.
• Suture - line of adherence of chamber wall(s) to previously formed test.
• Symbiosis - in foraminifera: algal cells living (as symbionts) within the foraminiferal cytoplasm in a mutualistic relationship with their host. The symbionts are actively photosythesizing and reproducing asexually in the host cell. They are involved in nutrient recycling. They live either in vacuoles of the host cytoplasm and are displaced passively by the host's protoplasmic streaming, or they are found in the lacunar system of the host cell within which they may move actively by means of their shortened flagella in order to regulate their irradiation by sunlight as to avoid photoinhibition. During asexual reproduction of the host, each offspring inherits a small number of symbionts from the mother cell. After sexual reproduction, the foraminiferal zygote must take up symbionts from its ambient environment. See also: chloroplast husbandry.
• Sympatric species or population - inhabiting common or largely overlapping areas of distribution.

• Tectorium - in fusulinids: slightly transparent internal shell layer lining the chamber walls and covered by the opaque tectum in the external, spiral wall. May be combined with a diaphanotheca.
• Tectum - thin, dense outer layer of the spirotheca (spiral outer wall) in fusulinids. Homologous in position to an epiderm but may be produced by different shell building processes. See also: marginal prolongation.
• Template - sheet of protein sustances on which biomineralization is started and which governs patterns, shapes and sizes of the biomineralized chamber wall. During chamber growth, the template is positioned  by the brush-like pseudopodia prior to biomineralization as visualized later by the median layer.
• Teratological - pathological alternation of shell morphology, for instance by loss of control to keep coiling axes or bilateral symmetry constant. Frequent in gerontic growth stages or after temporal extreme environmental conditions in tidal pools.
• Terminal - positioned at the distal end of a linear structure or of an elongate chamber.
• Test - shell or skeletal component of a foraminifer. May be composed of a variety of material secreted, agglutinated or both.
• Test-architecture - spatial arrangement of chambers, their subdivisions and their connections.
• Test-composition - mineralogical and chemical composition of test-walls.
• Test-structure - any pattern of elements subdividing chamber lumina.
• Test [wall]-texture - pattern of arrangement of crystallites, agglutinated grains, organic matter, pores, lamination or layering.
• Textural ornamentation - pattern of distinctive appearance of perforate chamber wall produced by local lack of pores. 225/5.
• Tongue - see toothplate.
• Tooth (pl. teeth, French: dents) - inward projection(s) of the inner portion of the chamber wall into the aperture. This structural element is a continuation of the basal layer and may be more or less modified but not suppressed when the aperture is transformed in an intercameral foramen. Teeth outgrowing from the basal layer may be complemented by local thickenings of the inner portion of the free, marginal chamber walls.   Remarks: Teeth may be defined as particular endoskeletal element restricted to the apertural area. The relation between teeth and pillars (in particular supporting a trematophore) on one hand, to valvular teeth in agglutinated and to toothplates in lamellar-perforate foraminifera on the other is a close one and may be transitional.  True teeth must be distinguished from tooth-shaped masks in Borelis obstructing the main apertures but resorbed totally in intercameral foramina. See also: milioline tooth; valvular tooth.
• Toothplate (sipho; central pillar, pars auct.) - a contorted plate running from an intercameral foramen to an aperture, attached to both. Folded in a single, double or spiral fold. Folds (or tongues) with free, often serrated distal ends and distally protruding into the aperture. A toothplate separates partly or entirely the main chamber lumen from an axial space (adapertural depression) in post-embryonic stages. Interconnected toothplates may produce a primary spiral canal. A toothplate  may be homologous with an umbilical plate, but is never associated with a foliar or stellar chamberlet and it does protrude with a free edge distally and adaxially to the aperture. 22/5. 109/3. 115/4. 118/7. 124/7. 127/2. 199/9,10.
• Trabecules [trabeculae] - imperforate shell material  extending from imperforate sutural zone into the perforate lateral chamber-wall and housing oblique, ramified canals (Hottinger, 1977).
• Transverse septulum - see beam.
• Trematophore - sieve-like plate covering the aperture and  produced by the coalescence of milioline teeth. 36/3 .59/1-5.This is in contrast to multiple apertures produced by the coalescence of peristomal rims, as in Coscinospira. 77/4.
• Triconch - first three chambers in megalospheric generation separated by plane, uncurved septa shaped by equilibrated hydrostatic pressure, probably during a single instar. May be enveloped by common secondary lamellas. Example: Planorbulinella.   Remarks: Drooger (1993) uses for the same feature the term tritoconch, a term which, however, is preoccupied for the third chamber in megalospheric Miniacina. See also: biconch.
• Triloculine - see milioline coiling.
• Trimorphism - morphologic differentiation of megalospheric generation in A1 and A2. A1 has a comparatively small megalosphere and reaches larger adult shell sizes than A2. The A1 shells are interpreted (Hofker, 1968) as representing diploid schizonts generated by the microspheric agamont, the A2 shells, after reduction division of the reproductive nuclei in A1, would represent haploid gamonts reproducing sexually. Thus, three different phenotypes would represent a (trimorphic) species. See also: alternation of generations.
• Triserial - chamber arrangement in a trochospire with three chambers per coil, hence with about 120° between median planes of consecutive chambers. 125/1-4.
• Trochospiral arrangement - chamber arrangement in whorls or coils where the rate of translation (net rate of movement along the growth axis to the net rate of movement away from the axis) is more than zero. Spiral and umbilical sides dissimilar. May be involute or evolute on either spiral or umbilical side. See also: reversed trochoid.
• Tube pillars - hollow pillars formed by folded septal flap, as in Chapmanina.
• Tubercle - see pustule.
• Tuberculate, papillate, pustulate - covered with tubercles, papillae or pustules. See also: pustule.
• Tubulopore - pore opening at the end of a conical or tubular projection. 149/2,4. 196/2,6.
• Tubulospines, tubulospinate - hollow pseudospines. The cavity represents a linear extension of the chamber lumen ending blindly below the tip of the pseudospines. Caution! Many pseudospines have been erroneously interpreted as hollow (as in Asterorotalia pulchella).
• Tunnel - Intercameral foramen in interiomarginal-basal position bordered by endoskeletal structures narrowing the communication between open chamber lumen and a spiral space trough successive tunnel foramina, and produced by resorption of parts of an apertural face and/or of an apertural mask. May be multiplied to form a single row of basal foramina.

     Remarks: Introduced originally for fusulinids, where the tunnel is bordered by chomata and may be multiplied together with the endoskeletal element (parachomata), the term has been extended to pfenderinids (Hottinger, 1978). In this family the tunnel is bordered by being incised in a columellar endoskeleton and may be multiplied as multiple, parallel incision in such complex genera as Sanderella. In addition, the term is extended here to nummulitids where the tunnel is bordered by a pair of umbilical plates in much the same position as the chomata in fusulinids. In nummulitids, sofar no multiplication of tunnels has been observed.

• Ultimate chamber - last chamber formed in an individual.
• Umbilical [intraumbilical] aperture - primary aperture of a chamber leading into umbilicus. 106/7.
• Umbilical bowl (pseudoumbilicus, pars auct.) - a deep, wide or narrow conical space in axial position formed between inner umbilical chamber walls, wherever the latter are separated from the outer umbilical walls by a distinct edge or shoulder. Compare: umbilicus; pseudoumbilicus. 198/5,8. 199/4,7,10.
• Umbilical canal system - umbilical interlocular space transformed into tubular cavities by various skeletal elements and chamber wall extensions (folia). Commonly modified by local resorption creating a network of communications between the tubular cavities. See also: spiral canal; vertical canal.
• Umbilical cavity - the axial complex of interconnected passageways delimited by axial chamber walls, inner umbilical walls, folia, foramenal plates, and cover plates. Includes thus the umbilical canal systems. May be restricted by piles or plugs and communicates with the exterior through foliar apertures or vertical canals. 203/11.
• Umbilical depression (umbilicus, pars auct.) - a closed depression in axial position formed by the curvature of the umbilical chamber-walls in the same coil. Compare: umbilicus; pseudoumbilicus) 154/7,9.
• Umbilical flap - rotaliellid extension of umbilical chamber wall deliminating narrow umbilicus and covering umbilical aperture. Anterior margin may be glued to umbilical wall of chambers in previous whorl.    Remarks: As the term "umbilical flap" was used earlier as a synonym of "umbilical plate" in rotaliids, its revival for umbilical chamber wall extensions in Rotaliellidae (by Pavlowski et al. 1992, fig.1) leads to confusion and should be abondoned. Umbilical chamber wall extensions in Rotaliellidae should be rather compared to structures in planktic foraminifera with comparably open, true umbilici and designated with corresponding terms.
• Umbilical plate (foramenal plate; umbilical flap; murus reflectus; toothplate; paries proximus, pars auct.) - a more or less contorted plate-like test element, extending between distal and proximal chamber walls and joined to both, attached to the intercameral foramen and to the main aperture, but not protruding into the latter. Separates the main chamber lumen from a primary umbilical-spiral canal - produced between plate and adjacent coil or by foliar chamberlets - or from stellar chamberlets. Between plate and adjacent coil or within the plate itself an opening provides connection between chamber and foliar or stellar chamberlet,wherever present.This opening may remain open in all chambers or it may be "plugged" in all but the ultimate chamber by a sealing plate. An umbilical plate may be single or composed of two symmetrical branches in some planispiral genera, thereby producing one or two umbilical-spiral canals between plate and adjacent coil. 180/11. 181/1,2,4. 185/7. 209/3,5. 221/3-4. 224/4,6.
• Umbilical plug (-pile, -mass, umbonal plug) - pile of lamellae forming solid, more or less free-standing plug in the center of the umbilicus, often separated from foliar tips by a spiral fissure. 201/4, 205/1.
• Umbilical primary aperture - see umbilical aperture.
• Umbilical shoulder - see umbilical bowl.
• Umbilical side - in trochospiral tests the side opposite to the spiral one. See also: ventral.
• Umbilical teeth - triangular modification of the lip over umbilical apertures, as in Globoquadrina.
• Umbilicate - possessing a true umbilicus on one side or on both sides (biumbilicate).
• Umbilicoconvex - in trochospiral shells: spiral side flattened to concave, umbilical side convex. Compare: spiroconvex.
• Umbilicus - axial space in spiral foraminifera communicating directly through apertures with surrounding main chamber lumina or foliar chamberlets. May be open or may be restricted by an umbilical plug. (Compare umbilical bowl; pseudoumbilicus; umbilical cavity; umbilical depression). 145/2. 195/1,2. 201/4.
• Umbo (central pillar, pars auct.) - expanding pile of thickened lamellae in axial position of involute or orbitoidal foraminifera (never associated with an open umbilicus or with canals) See also: pile; plug. 186/5,10.
• Unilocular (monolocular, monothalamous) - single-chambered.
• Uniserial - chambers arranged in a single row. Compare: biserial; triserial.

• Vacuolar system (in Monolepidorbis) - see lateral chamberlets.
• Valvular tooth - in agglutinated foraminifera: a flap-like extension from the distal margin of main aperture, partly restricting the latter. 22/8.
• Veneer - outermost array of more or less blocky or columnar calcite or aragonite crystallites belonging integrally to an outer lamella in bilamellar foraminifera.
• Ventral - the side of a flattened organism turned to its substrate, as opposed to dorsal. See also: umbilical side; spiral side; remarks to dorsal.
• Vertical canals (oblique canals, pars auct.) - tubular spaces more or less normal to the test surface produced by secondary lamination (which is strongly thinned) over several coils. They originate from the margins of sutural canals or fossettes, or of foliar apertures communicating with a spiral-umbilical canal. Vertical canals persist in secondarily laminated parts of the test as long as not covered by chamber space. 208/5, 210/2.
• Vestibule (Vorhof in German) - deuteroconch embracing a protoconch with a wide-open flexostyle by a hemicylindrical to almost cylindrical frontal wall bearing numerous apertures, as in Amphisorus and Marginopora (Lehmann, 1961).
• Vicarious - closely related taxa occupying identical or very similar niches ("ecological substitutes") in different regions.

• Whorl [coil] - single turn or volution of spiral test through 360°.

• Zygote - diploid cell resulting from fusion of two (haploid) gametes in sexual reproduction. The biomineralized envelope of the zygote is called microsphere. See also: Life cycle.