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Verhandl. Naturf. Ges. Basel

Vol. 84

No. 1

Pages 256-264

Basle, March 1974

Nomenclature of Some Large Eo-Oligocene Globigerinas


R. M. Stainforth, Victoria, Canada

With 1 Figure and 2 Plates


In the Middle Eocene of the tropics a group of large Globigerinas appeared, probably rooted in Globigerina triloculinoides Plummer. Their nomenclature is difficult because of wide but completely intergradational variability. A proposed solution is to name only the central form (here equated with Globigerina linaperta Finlay) and the extremes resulting from certain combinations of coiling para­meters. Other forms are not named individually, but instead are designated as morphologically intermediate between named species. Under this scheme the specific names remaining in formal use would be eocaena, gortanii (and perhaps corpulenta), venezuelana, tripartita, sellii and binaiensis. The names galavisi, oligocaenica, pseudoeocaena, pseudovenezuelana, rohri, tapuriensis, trilocularis, turritilina, winkleri and yeguaensis, among others, would be discarded because of either synonymy or indefinite position within the plexus. In temperate regions the group is less variable and the name Globigerina angiporoides Hornibrook is widely applied to its main representative.


It was largely at the prompting of Hans Kugler that the first descriptions were published of entire Tertiary foraminiferal assemblages from Trinidad, followed by more specialized studies of the planktonic taxa and their applications to zonation and correlation. Consequently it is appropriate to include in this Festschrift the following brief discussion of an element which is conspicuous among the Eo-Oligocene plankton but presents difficulties of nomenclature.

Bolli (1957, a, b) and others have illustrated the Tertiary planktonic Foraminifera of Trinidad, demonstrating that certain forms are both morphologically distinctive and stratigraphically restricted, so that a clear and reliable zonation can be based on their distribution in a sequence of sediments. Within the later Eocene and the Oligo­cene some of the more useful index species are Cassigerinella chipolensis, Cribrohant­kenina inflata, Globigerina ampliapertura, Globigerina angulisuturalis, Globigerina ciperoensis, several species of Globigerinatheka, the subspecies of Globorotalia cerro­azulensis, Globorotalia opima opima, Hantkenina species, Orbulinoides beckmanni and Pseudohastigerina micra. These are by no means the largest planktonic forms in the assemblages, and in fact the list includes two species so small as to be easily overlooked. Commonly more conspicuous than the taxa mentioned are large Globigerinas, which tend to dominate the deep-water assemblages of the upper Navet and lower Cipero Formations in Trinidad and their correlatives elsewhere. It would be convenient if these large and plentiful microfossils could be widely used as key forms in zonation, but unfortunately their classification and nomenclature present such difficulties that their stratigraphic utility is not proportional to their abundance.

One difficulty regarding their nomenclature is an artificial one which could be overcome if the necessity should arise. Because these large Globigerinas were so plentiful, they were among the first forms to be named by the pioneers of micro­paleontology fully a century ago. At that time standards were much less strict than now as regards selection and preservation of type specimens, permissible variability within a species, avoidance of homonyms and synonyms, and to some degree the adequacy of published descriptions and illustrations. Consequently several venerable species-names have remained in use (eocaena, eocaenica, globularis and trilocularis, for instance) long after their basic differences had become indefinite.

Much greater difficulty is presented, however, by the natural problem that a normal assemblage of these large Globigerinas forms a plexus within which the extreme forms are sharply distinct and yet are linked by every conceivable shade of inter­gradational variant. The statistical treatment of a part of the plexus (the Globigerina eocaena form) by Lindenberg (1969) demonstrates this subtle, virtually infinite, variability, which makes impossible any objective division of the entire suite into named species or subspecies. The sudden appearance of this

dorsal aspects


side views


ventral aspects



Fig. 1. Line drawings showing trends of variation in the Globigerina linaperta group. Not to scale, but diameters typically in range of 0.5 to 0.7 mm.

1 = linaperta, 2 = eocaena, 3 = corpulenta, 4 = gortanii, 5 = venezuelana, 6 = tripartita 7 = sellii, 8 = binaiensis.

group is one of several strange developments within the planktonic Foraminifera during the later Eocene, in the form of mutations and gerontism in hitherto stable lines: the hantkeninid and globigerinathekid lineages are other examples. By Oligocene time certain offshoots of the globigerinid plexus had proved viable and they can be found coexistent without intermediate forms (e.g. Globigerina gortanii, G. sellii and G. venezuelana).

Suggested nomenclature

Proposed below is a pragmatic scheme which evades the basic difficulty of discrete subdivision of a continuum, yet enables elements of the plexus to be recorded with sufficient accuracy for all normal stratigraphic purposes. The basic idea, developed in more detail in the following paragraphs, is to recognize a central form around which the variants can be arranged, leading to certain extremes. Specific names are given only to the central form and the main extremes, and all other variants are designated informally in the style of ‘intermediate between X and Y’, perhaps qualified as ‘closer to Y’. The line drawings on Figure 1 give an idea of the main trends of variation. Representative figures of the dorsal and side aspects of the main species are reproduced on Plates 1 and 2. (The ventral aspect is generally less diagnostic, so is omitted from the plates). The references indicated should be consulted for illustrations giving a more complete three-dimensional impression of the whole suite of variants.

A. The central form of the plexus is visualized as a species with a quadrate (rectan­gular) coil in which each successive chamber is approximately equal in size to the whole preceding coil, so that the outer whorl is composed of 3 1/2 chambers. Its gross aspect is neither compressed nor elevated and its chambers are neither strongly appressed nor loosely attached. The species Globigerina linaperta Finlay 1939 is one which matches this concept: see, for instance, Bolli (1957, b) and Hornibrook (1958). This modern name has been arbitrarily chosen to designate the group because older names for this form have mostly acquired a hazy connotation arising from their broad, indefinite usage in earlier literature.

B. The basic morphology of Globigerina is a set of inflated chambers whose mid­points are evenly spaced along a helix, Four independent elements of the trochospiral test are:

1.   Elevation of spire in side view, ranging from low (even flat) to lofty.

2.   Relative tightness or laxity of spiral as seen from above.

3.   Rate at which successive chambers increase in size, ranging from barely perceptible to a doubling or tripling of their diameters.

4.   Shape of individual chambers (globular, reniform, appressed, etc.) and whether constant or changing during growth.

In most globigerinid lineages a rather slow change is apparent in the over-all coiling pattern, so that the evolutionary stages have chronostratigraphic significance. The linaperta-group differs from the norm in that wide and sustained variation occurred simultaneously in all four parameters during middle to late Eocene time. A trained observer could readily specify five degrees of variation discernible within each of them: for example, the spire might be classed as depressed, low, distinctly raised, high or lofty. Since the parameters are independent of one another, it follows that one can visualize 5 x 5x 5 x 5=625 morphologically distinct variants within the linaperta-group. This figure gives a measure to the diversity and hence to the difficulty of applying a rational nomenclature to the plexus.

C. The variability so far discussed affects only the gross form of the test. In addition, with varying degrees of emphasis authors have based separation of taxa on features of the umbilicus, aperture, apertural lips and 'teeth', shell surface, and dwarfed final chambers (treated as bullas in some instances). The writer, however, has formed the opinion that most of these characters are not independent of the four coiling para­meters already described. The empirical evidence and the concept of geometrical growth both suggest that many interrelationships exist, some examples being that a slit-type aperture tends to carry a flange or lip; size of umbilicus is governed jointly by compactness of coiling and rate of enlargement of chambers; a gaping umbilicus tends to be ‘protected’ by flaps or toothlike flanges of shell material; a growth pattern of rapidly enlarging chambers might be metabolically impossible of achievement, resulting in aborted final chambers; and so forth. As regards shell surface, the writer agrees to its significance in certain cases (such as distinction of the cancellate genus Catapsydrax from the matte-surfaced Globigerinita) but does not consider it significant in the present context. Modern authors have shown by use of the scanning electron microscope that differential solution can modify the surface texture of planktonic

Foraminifera extensively: see, for instance, striking SEM photos of Cita (1971). This is especially true of deep-water assemblages, to which belong almost all micro­faunas with a rich representation of the Globigerina linaperta-group.

D. Four main lines of morphologic variation can conveniently be recognized, all centred in the form linaperta but leading to the markedly dissimilar end-forms describ­ed below.

1. Forms which differ from linaperta in appreciably lower rate of enlargement of chambers, resulting in a more open umbilicus around which the last 4 chambers are fully visible. The prior name for this form appears to be Globigerina eocaena Gümbel 1868, based on the neotype designated for this species by Hagn and Lindenberg (1966). Within the limits of tolerance here applied, the name yegua­ensis of Weinzierl and Applin (1929) and many subsequent American authors is a junior synonym.

2. Forms similar to eocaena but further differing from linaperta by developing an appreciably elevated coil. The extreme form is a lofty spire of globular chambers, aptly compared to a bunch of grapes ('traubig') by Hagn and Lindenberg (1969). Its prior name is Globigerina gortanii (Borsetti 1959), which is a senior synonym of the name turritilina proposed by Blow and Banner (1962). On principle the writer would prefer not to name the intermediate forms, neither as depressed as eocaena nor as lofty as gortanii, but he is aware of their wide recognition and stratigraphic use under the name Globigerina corpulenta Subbotina 1953.

3. Forms which initially resemble linaperta in dorsal aspect but differ in progressive appression and ventral prolongation of the chambers, whose extremities curve in and define a rectangular umbilicus around which 3 1/2 chambers are generally visible. Gross shape of the test becomes cuboidal to spheroidal. This branch is exemplified by Globigerina venezuelana Hedberg 1937.

4. Forms similar to venezuelana in the ventral prolongation and incurving of the chambers, but further differing from linaperta by accelerated enlargement of successive chambers, so that only 3 chambers form the outer whorl and the umbili­cus becomes triangular. This is Globigerina tripartita, a name derived from G. bulloides tripartita Koch 1926 and now accepted as a prior synonym of G. rohri as described by Bolli (1957 a). By exaggeration of this trend the distinctive, Oligocene species G. sellii (Borsetti 1959) (= G. clarae Bermúdez 1960 G. oligocaenica Blow and Banner 1962) and the almost bizarre G. binaiensis Koch 1935 were produced.

E. In summary, it is proposed to apply only the specific names eocaena, gortanii (and perhaps corpulenta), venezuelana, tripartita, sellii and binaiensis among the forms under consideration. The underlying concept is that confusion arises and communication breaks down when attempts are made to divide any continuum artificially. For instance, the division of the natural light-spectrum into seven colours is satisfactory for broad purposes (namely violet, indigo, blue, green yellow, orange, red), but endless inconclusive argument can arise over placement of intermediate hues such as turquoise and chartreuse. By analogy, the Globigerina linaperta-group can be applied more readily to stratigraphy if only a few of its distinctive forms are recognized than if one attempts to name every subtle variant in the plexus. It follows that, for pragmatic purposes, the writer would recommend disuse of other names, some of which have been used more or less extensively. The following comments enlarge upon this aspect.

Globigerina ampliapertura Bolli, 1957 a

This species is only mentioned here because it also falls in the category of large Eo-Oligocene species of Globigerina. Its chamber form and aperture reflect its globo­rotaliid ancestry, so that confusion with the G. linaperta-group is unlikely. The closest variants to it are certain forms of G. venezuelana, but in dorsal view their short intercameral sutures are approximately radial whereas in G. ampliapertura they are tangential to the inner whorl. G. prasaepis Blow 1969, originally figured as ‘G. ampli­apertura euapertura’ by Blow and Banner (1962), is here regarded as merely a low-­apertured variant of G. ampliapertura.

Globigerina angiporoides Hornibrook 1965

In temperate latitudes the more extreme variants of the G. linaperta-group are seldom recorded, perhaps because their distinctive features appear only in large adult specimens and these are encountered mainly in warm-water assemblages. In cooler regions a smallish, compact form may be plentiful and has been referred by authors in both hemispheres to G. angiporoides, a species originally described from the Oligocene of New Zealand. It was figured as ‘G. linaperta linaperta’ by Blow and Banner (1962), fide Blow (1969, p. 315).

Globigerina galavisi Bermudez 1960

Blow (1969) refigured the holotypes of both G. galavisi and G. yeguaensis, claiming them to be distinct species, but to the present writer the figures could re­present a single specimen drawn by different artists. Both forms are here placed in synonymy with G. eocaena.

Globigerina euapertura Jenkins 1960

Blow and Banner (1962) used this name for a variant of the Eo-Oligocene G. ampliapertura but Blow (1969, p. 382, 383) indicated that this treatment was erroneous. Nevertheless, Jenkins’s figures (1960, also 1971) depict an Oligo-Miocene form with a coil more suggestive of G. ampliapertura (see comments above) than of the G. linaperta-group.

Globigerina gortanii praeturritilina (Blow and Banner 1962)

This subspecies, originally ascribed to ‘Globigerina oligocaenica’, differs only in minor details from the main form.

Globigerina pseudoeocaena Subbotina 1953 and its subspecies

Subbotina (1953, also 1971) provided a suite of excellent drawings of Paleogene Globigerinas, many of which might be placed in the G. linaperta-group. She referred many large specimens to the subspecies pseudoeocaena s. s., compacta and trilobata of her new species G. pseudoeocaena, which was differentiated from G. eocaena by ‘more rapid growth of the chambers to the last whorl’ (1971, p. 80). Under the treatment here proposed, these forms would fall indefinitely between G. eocaena and G. linaperta. Subbotina recognized the close relationship of G. pseudoeocaena, also her G. corpulenta, to G. eocaena (1971, p. 50, 104) and hinted that her G. inaequispira might be another offshoot typified by loose attachment of its chambers (p. 85).

The nomenclatural difficulty of the plexus is epitomized by the fact that other experts have differed from Subbotina’s carefully expressed and unusually well illustrated treatment. Blow and Banner (1962) treated her G. pseudoeocaena as a subspecies of G. linaperta and suggested that part of her G. eocaenica also belongs here. Hagn and Lindenberg (1969) rejected her identification of G. eocaena but included her ‘new’ G. pseudoeocaena in their synonymy of Gümbel’s species. To the present writer the weak point in Subbotina’s treatment was the artificial but rigid separation of ‘tetrathalamous’ and ‘trithalamous’ Globigerinas (1971, p. 47), which prevented her from even comparing the forms which she placed in G. eocaena and G. eocaenica, both of which appear to belong to the G. linaperta-group as defined here.

Globigerina pseudovenezuelana Blow and Banner 1962

Originally described as ‘Globigerina yeguaensis pseudovenezuelana’, this form was treated as a full species by Blow (1969), whose range-charts indicate a mid-Oligocene gap between extinction of G. pseudovenezuelana and first appearance of G. venezuelana. To the writer it falls within the range of intraspecific variability reasonably attributed to the single species G. venezuelana. Bolli (1957a, b) has expressed a comparable view and his charts show G. venezuelana extending continuously from a mid-Eocene level up into the Miocene. It may be noted here that Blow and Banner (1962, p. 101) gave reasons for treating as nomina dubia the names Globigerina bulloides quadri­partita Koch 1926 and Globigerina rotundata jacksonensis Bandy 1949, both of which might be identical with their species pseudovenezuelana.

Globigerina tapuriensis Blow and Banner 1962

First described as ‘Globigerina tripartita tapuriensis’, this form was raised to the species level by Blow (1969). The writer agrees with Blow's concept that it is transi­tional between G. tripartita and G. sellii, but finds it impossible to set objective criteria for distinguishing it with certainty from either of the adjacent species. This is a clear example of the choice between classification in the form ‘sp. X/transitional forms/sp. Z’ or ‘sp. X/sp. Y/sp. Z’.

Globigerina trilocularis D’Orbigny 1826

This name has occasionally been revived, for instance by Bolli (1957a, b), for Globigerinas including elements of the G. linaperta-group, but Blow and Banner  (1962, p. 94) have given cogent reasons for discarding it.

Globigerina triloculinoides Plummer 1926

This is a form with the same basic coiling as G. linaperta, but is generally smaller and less compact, with a conspicuously reticulated surface. It is most abundant in the older Paleogene and may well be ancestral to the G. linaperta-group. Loeblich and Tappan (1957) have provided a useful review of this species.

Globigerina winkleri Bermudez 1960

Despite acceptance of this form as a stratigraphically useful species by Blow  (1969, p. 323), the writer finds it an indefinite variant within the G. linaperta-group,  in the vicinity of G. corpulenta.


The ideas expressed here have developed gradually, influenced by discussions and correspondence with colleagues too numerous to list. My thanks to all of them, and especially to the late Dr. Walter Blow and to Dr. Hanspeter Luterbacher. The latter suggested inclusion of Globigerina inaequispira Subbotina 1953 in the G. linaperta-group, a plausible idea which merits further attention.

Plate 1

Reproductions of published dorsal views of species assigned to the Globigerina linaperta-group. Note different magnifications, which are same as originals. Note similarity of juvenile coils in contrast to pronounced differences of adult chambers.

Fig. 1         Globigerina eocaena Gümbel, x 78. Neotype from Bavaria as figured by Hagn and Lindenberg (1969).

Fig. 2         Globigerina eocaena Gümbel, x 67. Holotype of the synonymous Globigerina yeguaensis Weinzierl and Applin from Texas as re-figured by Blow (1969).

Fig. 3         Globigerina linaperta Finlay, x 100. Specimen from Trinidad as figured by Bolli (1957), closely similar to the holotype from New Zealand as figured by Finlay (1939) and re-figured by Hornibrook (1958) and Jenkins (1971).

Fig. 4         Globigerina venezuelana Hedberg, x 68. Specimen from Trinidad as figured by Bolli (1957a), intermediate between globose and appressed extremes of this form.

Fig. 5         Globigerina gortanii (Borsetti), x 70. Holotype from Italy as figured by Borsetti (1959).

Fig. 6         Globigerina tripartita Koch, x 75. Holotype from Borneo as re-figured by Blow and Banner (1962).

Fig. 7         Globigerina binaiensis Koch, x 115. Approximate topotype from Borneo as figured by Blow (1969).

Fig. 8         Globigerina sellii (Borsetti), x 75. Holotype of the synonymous Globigerina oligocaenica from Tanzania as figured by Blow and Banner (1962).

Large Eo-Oligocene Globigerinas Plate I

Plate 2

Reproductions of published side views of species assigned to the Globigerina linaperta-group. Same suite of specimens as shown on Plate 1.

Fig. 1         Globigerina eocaena Gümbel, x 78. Neotype from Bavaria as figured by Hagn and Lindenberg (1969).

Fig. 2         Globigerina eocaena Gümbel, x 67. Holotype of the synonymous Globigerina yeguaensis Weinzierl and Applin from Texas as re-figured by Blow (1969).

Fig. 3         Globigerina linaperta Finlay, x 100. Specimen from Trinidad as figured by Bolli (1957), closely similar to the holotype from New Zealand as figured by Finlay (1939) and re-figured by Hornibrook (1958) and Jenkins (1971).

Fig. 4         Globigerina venezuelana Hedberg, x 68. Specimen from Trinidad as figured by Bolli (1957 a), intermediate between globose and appressed extremes of this form.

Fig. 5         Globigerina gortanii (Borsetti), x 70. Holotype from Italy as figured by Borsetti (1959).

Fig. 6         Globigerina tripartita Koch, x 75. Holotype from Borneo as re-figured by Blow and Banner (1962).

Fig. 7         Globigerina binaiensis Koch, x 127. Approximate topotype from Borneo as figured by Blow (1969).

Fig. 8         Globigerina sellii (Borsetti), X 75. Holotype of the synonymous Globigerina oligocaenica from Tanzania as figured by Blow and Banner (1962).

Large Eo-Oligocene Globigerina Plate 2



Bandy, O. L. (1949): Eocene and Oligocene Foraminifera from Little Stave Creek, Clarke County, Alabama. Bull. Am. Pal. 32/131, 1-210.

Bermudez, P. J. (1960): Contribución al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Mem. III Congr. Geol. Venezol. Caracas 3, 1119-1393.

Blow, W. H. (1969): Late Middle Eocene to Recent Planktonic Foraminiferal Biostratigraphy. Proc. 1st. Int. Conf. Plankt. Microfossils 1, 199-422.

Blow, W. H., and Banner, F. T. (1962): The Mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In: Eames, F. E., Banner, F. T., Blow, W. H., and Clarke, W. J.: Fundamentals of Mid-Tertiary Stratigraphical Correlation. Cambridge Univ. Press, p. 61-151.

Bolli, H. M. (1957): The Genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad, B. W. I. U.S. Nat. Mus. Bull. 215, 61-81.

— (1957 a): Planktonic Foraminifera from the Oligocene-Miocene Cipero and Lengua Formations of Trinidad, B.W.I. U.S. Nat. Mus. Bull. 215, 97-131.

— (1957b): Planktonic Foraminifera from the Eocene Navet and San Fernando Formations of Trinidad, B.W.I. U.S. Nat. Mus. Bull. 215,155-172.

Borsetti, M. E. (1959): Tre nuovi foraminiferi planctonici dell'Oligocene Piacentino. Gn. Geol. (2) 27, 205-212.

Cita, M. B. (1971): Paleoenvironmental Aspects of DSDP Legs I-IV. Proc. II Plankt. Conf. 1, 251-285.

Finlay, H. J. (1939): New Zealand Foraminifera: Key Species in Stratigraphy No. 3. Trans. Roy. Soc. N. Z. 69/1, 89-128.

Gümbel, C. W. (1868): Beitrage zur Foraminiferenfauna der nordalpinen, älteren Eocängebilde oder der Kressenberger Nummulitenschichten. Abh. k. bayer. Akad. Wiss. (II) 10, 579-730.

Hagn, H., and Lindenberg, H. G. (1966): Revizija Globigerina (Subbotina) eocaena Gümbel iz Eocena predgorij Bavarskich Al’p. Voprosy Mikropal. 10, 342-358.

— (1969): Revision der von C. W. Gümbel 1868 aus dem Eozän des bayerischen Alpenvorlandes beschriebenen planktonischen Foraminiferen. Proc. 1st. Int. Conf. Plankt. Microfossils 2, 229-249.

Hedberg, H. D. (1937): Foraminifera of the Middle Tertiary Carapita Formation of Northeastern Venezuela. J. Paleont. 11/8, 661-697.

Hornibrook, N. DE B. (1958): New Zealand Upper Cretaceous and Tertiary Foraminiferal Zones and some Overseas Correlations. Micropaleontology 4/1, 25-38.

— (1965): Globigerina angiporoides n.sp. from the Upper Eocene and Lower Oligocene of New Zealand and the Status of Globigerina angipora Stache 1865. N. Z. J. Geol. Geophys. 8/5, 834-838.

Jenkins, D. G. (1960): Planktonic Foraminifera from the Lakes Entrance Oil Shaft, Victoria, Australia. Micropaleontology 6/4, 345-371.

— (1971): New Zealand Cenozoic Planktonic Foraminifera. N. Z. Geol. Surv. Pal. Bull. 42, 1-278.

Koch, R. (1926): Mitteltertiäre Foraminiferen aus Bulongan, Ost-Borneo. Eclogae geol. Helv. 19, 722-751.

— (1935): Namensänderung einiger Tertiar-Foraminiferen aus Niederländisch Ost-Indien. Eclogae geol. Helv. 28, 557-558.

Lindenberg, H. G. (1969): Statistical Notes on the Variability of Globigerina eocaena Gümbel, 1868, from the Paleogene of the Bavarian Alps. Proc. 1st Int. Conf. Plankt. Microfossils 2, 344-365.

Loeblich, A. R., Jr., and Tappan, Helen (1957): Planktonic Foraminifera of Paleocene and Early Eocene Age from the Gulf and Atlantic Coastal Plains. U.S. Nat. Mus. Bull. 215, 173-198.

Plummer, H. J. (1926): Foraminifera of the Midway Formation in Texas. Univ. Texas Bull. 2644,1-206.

Subbotina, N. N. (1953): Iskopaemye foraminifery SSSR (Globigerinidy, Hantkeninidy, i Globoro­taliidy). Vnigri Trudy [n.s.] 76,1-239.

— (1971): Fossil Foraminifera of the USSR. Globigerinidae, Hantkeninidae and Globorotaliidae. Translated by E. Lees, 320 p. (London and Wellingborough, Collet’s Ltd.).

Weinzierl, L. L., and Applin, E. R. (1929): The Claiborne Formation on the Coastal Domes. J. Paleontol. 3, 384-410.

Author's address: Dr. R. M. Stainforth, 925 Terrace Avenue, Victoria, B.C., Canada.

Manuscript received 5 January 1973.