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Volume 66, 1937
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Review of the Tertiary and Recent Neozelanic Pyramidellid Molluscs

No. I.—The Genus Turbonilla.

[Read before the Auckland Institute, August 11, 1936; received by Editor, September 7, 1936; issued separately, March, 1937.]


The present survey of the Pyramidellid fauna marks the first occasion on which the Neozelanic groups of this family have been intensively studied. Prior to this earlier workers had placed on record some 64 species in all; but, apart from the description of new specific forms as they happened to be discovered, no serious attention had been given to the group. Early in the present investigation it became obvious that both fossil and Recent Pyramidellids existed in much greater numbers, both specifically and generically, than these earlier records led one to suppose. The number of species has been very considerably added to, and the original 64 will have to be increased to 223. As regards generic groups, it will be necessary to institute 17 new names, while 10 genera previously found only in extra-Neozelanic regions will be shown to have representatives in the New Zealand fauna.

Basis of Classification.

In most groups to be discussed the classification has been based in the first instance on nuclear characters. The Pyramidellid protoconch is heterostrophe, but the coiling of the embryo falls into two main types, (a) that coiled in a helicoid spiral, usually possessing a small, closely coiled, centrally situated nucleus, and, (b) that coiled in a planorboid spiral, of fewer volutions, and with the nucleus large and nearer one side. These differences approximately correspond to two of those outlined by Finlay (Trans. N.Z. Inst., vol. 31, p. 8; 1931) for normally coiled apices, (a) being polygyrate, (b) paueispiral. No horny protoconchs are known in the Pyramidellidae. Dall and Bartsch (A Monograph of West American Pyramidellid Molluses, Bull. U.S. Nat. Mus., 1909) apparently have not regarded the character of the embryo generally as of systematic significance, except, however, in the case of Nisiturris, which, in their key of subgenera, is separated from Chemnitzia by its pupoid nuclear habit.

It will be seen that in this review the subgenera admitted by Suter, following, no doubt, Dall and Bartsch, have been elevated to generic rank. They are each individually well marked and easily defined, and it is considered that their employment as full genera renders the systematics of the Pyramidellidae much less cumbersome than if a multitude of subgeneric groups were recognised. In this connection Iredale (Trans. N.Z. Inst., vol. 47, p. 461, 1915) commented on the subdivision of Odostomia: “Suter has here accepted

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the incongruous association considered a genus by Dall and Bartsch. This method of accepting a huge unwieldy group with a multitude of sections, many of which seem unnecessary, does not appeal to me. A large number of well-defined groups, considered as genera, makes a much more workable system, …” The same writer (loc. cit., p. 452) has advocated full generic value for the Neozelanic subgenera quoted by Suter (Eulimella, Syrnola, Turbonilla, Odostomia, Evalea, Pyrgulina).

Discrimination of Species.

The determination of species recognised in this review rests on consideration of a number of variable shell-characters, as can be seen by reference to comparisons given below the descriptions of species.

It may be permitted briefly to survey some of the chief characters that are herein employed to distinguish species. The shape or build of whorl is a valuable criterion, and shows all manner of variation from that which is strongly convex to one which is flat or even rendered somewhat concave, at least over one portion, by reason of the presence of a sulcus. Convexity may be even throughout the width of whorl; there may be a more or less pronounced zone of greater bulging, which, if present, usually marks the periphery; posteriorly the whorl may recede rapidly to the suture causing the formation of a narrow shoulder or even a definite tabulation. Whorls that bulge anteriorly are frequently flattish behind, and they clasp the previous whorl in tangential fashion, so that the suture becomes indistinctly defined. The character of the suture also varies in different species. There may be a slight channelling, or it may be impressed, or else tangential and clasping.

The axial sculpture shows a good deal of variation amongst different species, particularly as regards strength, degree of persistence across whorl, shape in cross-section, spacing and direction or trend. Other valuable criteria are to be had in the angle of spire, involving attenuation; outline of spire, which varies from that which is straight to that which is lightly convex throughout its height, or else convex behind and straight in front, giving the shell a characteristic pupoid summit. In addition, the arrangement and disposition of spiral ornamentation and the shape of aperture are also of importance in drawing specific distinctions.

Nor would one expect the minor details of the embryonic whorls to be of constant character within a genus, though they must conform to one general type. The helicoid embryo, for instance, varies in the degree to which it is exsert, and slightly in the number of its volutions; it may be coiled in a high helicoid spiral, the nucleus then projecting more or less strongly and overhanging the first adult whorl; or the helicoid spiral may be low and not conspicuous without careful examination; there is variation in the degree of convexity over the summit of the embryo, some species having a broadly convex protoconch and others one that is more narrowly convex and presents a sharper summit to the shell.

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In examination of fine sculpture and of apices each of the many hundreds of shells studied has been inspected microscopically, and all identifications should be made in like manner. Gross sculpture and shell-form have been studied under the hand-lens.

Fully 95 per cent, of the specimens that have been available to the writer have been “dead” shells, so that it has not been possible to study animal characters, or to attempt to make use of them in classification. The radula, so important in the systematic classification of many groups of gasteropods, is a degenerate organ amongst the Gymnoglossa, to which Superfamily the Pyramidellidae belong.

In comparison with foreign Pyramidellidae, particularly those of more tropical seas, the Neozelanic groups present a very striking monotony of ornamentation. Highly sculptured forms such as Bartschella, Oscilla, Ividella are noticeably absent from the New Zealand fauna.

Advance Statement Concerning Division into Groups of Genera.

Turbonillid genera: Typically considerably elevated shells of many whorls, having pronounced axial ribs, with or without spiral ornamentation. The columella has no fold, but a very low plication sometimes can just be seen. The embryonic shell is always prominent, often distinctly exsert, as in Syrnola, and not depressed as in Odostomia.

Odostomid genera: These have few whorls, a not greatly elevated spire, a single columella-fold, and typically a depressed embryo. The sculpture varies from shells devoid of all ornamentation to those with either axial ribs or spirals, or with both.

Pyrgulinid genera: Characterised by only moderately high conic habit, few whorls, and a single plait on the columella. There are more or less prominent axial ribs usually evanescing on the base, together with intercostal spirals of much less strength than the ribs. These two features of ornament determine the separation from true Odostomia.

Genus Evalea: Axial ribs are absent; axial sculpture in the form of very fine threads fenestrating the incised spiral grooves may, or may not, be present. Spiral sculpture consists of sub-equally spaced incised lines or narrow grooves over the entire adult surface, but weaker on the base. Typically the heterostrophic protoconch is considerably immersed, so that the nucleus is invisible or nearly so, giving a blunt effect to the top of the shell.

Syrnolid genera: Typically considerably elevated, often very attenuate, and imperforate, with a single more or less strong plait on the columella, and a strongly exsert, Turbonilla-like larval shell. Axial sculpture is usually not present, but in Costosyrnola n.gen. axial ribs are developed, though they become obsolete early on posterior part of whorls.

Eulimellid genera: Shell considerably elevated, Turbonilla-like in form; unsculptured; columella without a fold.

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The Turbonillid Group of Genera.

Turbonillids are typically considerably elevated shells of many whorls, having pronounced axial ribs, with or without spiral ornamentation. A feature of the aperture is the absence of a fold on the columella, or, if a fold is present, it is weak, low and almost obsolete. The embryonic shell is always prominent, often distinctly exsert as in Syrnola, and not depressed as in Odostomia.

In New Zealand no Turbonillids range in time beyond the Tertiary; their earliest appearance in this area is in rocks of midand Upper Eocene age, represented by the greensands of the Bortonian and Tahuian stages along Waihao River, South Canterbury, and by the Bortonian beds at Hampden, North Otago. Only six species appear in these early faunas, and all are very definitely limited in the number of individuals. Turbonilla s.str. and Pyrgiscilla* n.gen. seem to have been the first to appear, a single specimen of Turbonilla, T. arcana n.sp., having been found in Bortonian greensands at Waihao Downs, while two spirally striated forms, hampdenensis (Allan) and adeps n.sp., which have herein been placed in the new genus Pyrgiscilla, occur at Hampden. Thereafter, in the Tahuian, two further species of Turbonilla s.str. make their appearance in greensands at McCullough's Bridge. The early Tertiary members of Pyrgiscilla seem not to have flourished in numbers, with the exception, however, of P. chattonensis (Marwick), which is quite plentiful in the Ototaran beds at Chatton. Peculiarly enough Pyrgiscilla, which is not represented in beds of Hutchinsonian and Awamoan age, though other Turbonillids abound in these horizons, appears again in two separate specific forms in the Recent fauna. It is possible, however, that these are not direct descendants of pre-Hutchinsonian Pyrgiscilla, but that they have arisen from other Turbonillid stock and have converged on their Tertiary counterparts. Or perhaps they are immigrants descended from foreign relatives of the Ototaran stock.

Eight of the thirteen genera occur in beds of Hutchinsonian times (Upper Oligocene), while seven are found in Awamoan beds (Lower Miocene). Of these, three (viz., Mormula, Pyrgiscus, Pyrgolampros) are entirely limited in New Zealand to both the Hutchinsonian and Awamoan. Strioturbonilla, Striarcana n.gen. and Taurangia n.gen. are known here in the Recent fauna only. It is noteworthy that Turbonilla Group A (that is, Turbonillas with helicoid protoconchs) does not appear later than Upper Miocene (Taranakian) times, after which its place is taken by Turbonilla Group B (that is, Turbonillas with planorboid embryo), which first became known in Hutchinsonian faunas, where it is represented by

[Footnote] * The new genera referred to in the present part of the review will be formally proposed and diagnosed as they come to be dealt with in subsequent papers.

[Footnote] † There is, however, a species of Turbonilla Group A in the Waitotaran (Lower Pliocene) beds at Kaawa Creek. This is not altogether surprising, for, as has been remarked by the writer (Trans. Roy. Soc. N.Z., vol. 66, pp. 38–9, 1936), these beds contain a substantial element of distinct Miocene aspect.

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only a single species. From the point of view of time-range this latter is the most persistent group in the Turbonillid fauna, for it occurs not only in Upper Oligocene beds but also in the Lower Miocene, in the mid-Pliocene, and as an important constituent of the Recent fauna.

True Chemnitzia seems to have arrived later, for no undoubted representatives existed in this region before Lower Pliocene times.

As regards species none save Pyrgiscus abjunctus n.sp. and Chemnitzia brevisutura n.sp. (both Hutchinsonian and Awamoan): Chemnitzia kingi n.sp. (Nukumaruan to Recent); Chemnitzia zealandica Hutton and Chemnitzia jactura n.sp. (Castlecliffian to Recent); Pyrgiscilla hampdenensis (Allan), Bortonian and Tahuian, range from one stage to another. This would suggest that the Turbonillid stock was sufficiently plastic to yield readily to environmental influences, and the very circumscribed distribution of many of the Recent species seems to lend support to this view.

The classification into groups has been made in the first instance on nuclear characters, which, as pointed out earlier, may be either helicoid (polygyrate) or planorboid (paucispiral). In their monograph of the West American Pyramidellidae Dall and Bartsch record only 7 or 8 Turbonillid species as possessing embryos of planorboid coiling. This low percentage of planispiral apices amongst West American forms is in marked contrast with that of those in the New Zealand area, where 28 out of the 90 odd species have embryos of planispiral type.

The tabular summary of the classification adopted (given below) shows that the nature of the stoppage of the intercostal spaces has provided a ready and natural means of further subdivision. Dall and Bartsch (Monograph, p. 11) have distinguished Turbonilla s.str. from Chemnitzia by this character, but have not applied it to separate out groups from other Turbonillid genera. This omission must be regarded as an inconsistency, for it is surely logical to use this same criterion to make divisions amongst the other generic groups. Thus, for example, it has been necessary to recognise Pyrgiscilla n.gen. (grooves abruptly stopped) as distinct from Pyrgiscus (grooves slowly evanescent). The same separative character again appears amongst groups possessing planispiral apices. It will be seen from the tabular summary that this criterion is employed as a distinguishing feature between Strioturbonilla and Pyrgolampros. Dall and Bartsch have separated these two groups on apertural shape, which seems a quite unsatisfactory definition, especially since the shape of the aperture varies amongst species of any one genus. It is claimed that the criterion herein adopted gives a quite definite and natural means of separation, and further it is one that it has been found necessary to apply in studying the other Turbonillid genera. As it happens, however, the figures of the various species of Pyrgolampros given by Dall and Bartsch in their monograph show the grooves and axials extending on to and dying out gradually over the base, so that all these species appear to be correctly placed. But amongst their Strioturbonilla two species (judging by their figures again) show the axial and intercostal cessation characteristic of Pyrgolampros,

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for S. galapagensis Dall and Bartsch, though having the apical whorls decollated, seems better located in Pyrgolampros, and S. undata Carpenter, though an entirely different build of shell, should possibly go with it.

It will be shown later in discussing the characters of Chemnitzia that it is the manner of cessation of intercostal spaces rather than that of axial ribs that must provide a separation from Turbonilla s.str. In the latter the grooves die out gradually over the base, and the intervening axial ridges evanesce in like manner. In Chemnitzia, however, the anterior ends of the intercostal spaces end abruptly in alignment, each at a more or less vertical escarpment leading up on to the base of the shell. Dall and Bartsch have not made this distinction clear, and accordingly some misunderstanding has arisen, at least amongst local workers, as to the nature of the separation that should be drawn between these two genera.

Turbonilla s.l. is a world-wide genus with a host of species showing all manner of variation in axial and spiral sculpture and in whorl-shape and spire-outline, and one must, then, either put many forms together or separate them out on small characters.

In every case the number of axials has been reckoned on the penultimate whorl. This has been found necessary as senescent axial acceleration frequently becomes very marked on the last whorl of many individuals, and this, of course, is to be regarded as an abnormal condition.

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Summary of Classification of Turbonillids and Key to Genera.
Helicoid Protoconch. Planorboid Protoconch.
Spiral Sculpture. Grooves stopped. Grooves not stopped. Grooves stopped. Grooves not stopped.
Absent Chemnitzia A Turbonilla A Chemnitzia B Turbonilla B
Very fine scratches or wavy grooves* Striotur bonilla Pyrgolampros Striarcana n. gen. Taurangia n. gen.
Moderately strong spirals and grooves Pyrgiscilla n. gen. Pyrgiscus Gispyrella n. gen. Planpyrgiscus n. gen.
Strong distant raised spirals No Neozelanic Representatives
Moderately strong spirals and varices Mormula

[Footnote] * These vary from the excessively fine, regular microscopic spirals of Striarcana and Taurangia to the less regular, though coarser striations of Strioturbonilla, which can be detected by the use of a hand-lens, though not by the unaided eye.

[Footnote] † These can frequently be picked up by the unaided eye, and in good shells are always easily seen under a hand-lens. Microscopic inspection is not necessary for their detection. The grooves are quite definite and usually well incised, and much coarser than the “wavy grooves” of the former class.

[Footnote] ‡It has not been possible to determine whether the embryos of the type species of Turbonilla and of Chemnitzia are helicoid or planorboid, and for this reason it has been impossible to institute new generic names for either Chemnitzia A or Chemnitzia B and for either Turbonilla A or Turbonilla B.

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[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Time-Ranges of Turbonillid Genera.
Bortonian. Tahuian. Waiarekan. Ototaran. Waltakian. Hutchinsonian. Awamoan. Taranaklan Waltotaran. Nukumaruan. Castlecllfflan. Recent.
Turbonilla A
Turbonilla B
Chemnitzia A ??
Chemnitzia B
Pyrgiscilla n. gen.
Gispyrella n. gen.
Planpyrgiscus n. gen.
Striarcana n. gen.
Taurangia n. gen.
?? C. haugrandis Marwick. Poorly preserved and may have spirals.
Time-Ranges of Species of Turbonilla.
Bortonian. Tahuian. Walarckan. Ototaran. Waltakian. Hutchinsonian Awamoan. Taranakian. Waltotaran. Nukumaruan. Castlecliffian. Recent.
Turbonilla A
Turbonilla B
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Group A.—Nuclear Character Helicoid (Polygyrate).

This major division embraces the following genera:—

  • Turbonilla A of this paper.

  • Chemnitzia A of this review.

  • Strioturbonilla Sacco.

  • Pyrgolampros Sacco.

  • Pyrgiscus Philippi.

  • Pyrgiscilla n.gen.

  • Mormula A. Adams.

Genus Turbonilla Risso.

1826. Risso, Hist. Nat. Eur. Mer., vol. 4, p. 224.

Type (fide Dall and Bartsch): Turbonilla typica Dall and Bartsch = plicata Risso.

Turbonilla Group A.

The three important characters that serve to distinguish Turbonilla A are helicoid protoconch, gradual evanescence of intercostal spaces on the base of the shell, and absence of spiral sculpture. In their diagnosis Dall and Bartsch state that the axial ribs “extend from the summits of the whorls to the umbilical region.” None of of the Neozelanic species studied during this revision show an extension of axial sculpture as far forward as the region of the umbilicus, and in several species (e.g., T. suteri) the ribbing and grooves die out almost at the periphery or only a little below it.

The prolongation of axial ribs over the base is not considered of paramount importance, for, as will be pointed out in the introductory remarks under Chemnitzia, faint basal ribbing is often observable on shells of that group, though this feature may not be constant within a species. It is, as has been shown, the manner of cessation of the intercostal spaces that should provide the means of separation.

The embryo is heterostrophic and helicoid, of about 2 volutions, the lateral nucleus central or thereabouts.

Key to Species of Turbonilla A.

Shell 6.0 mm. long or over.
Outlines of spire straight throughout.
Shell attenuated, whorls flattish.
Whorls distinctly medially sulcate.
Axials very oblique, heavy; whorls narrow, staged. agrestis.
Axials vertical, moderately heavy. pukeuriensis.
Whorls straight or faintly concave above, bulging below.
Early whorls convex, later ones flat; axials not strong. awasimulans.
All whorls flat; axials strong. speighti.
Axial obsolescence marked. comitas.
Whorls with strong concavity at upper third; shell very attenuate; axials oblique to right. macies.
Spire high but hardly attenuate.
Whorls regularly convex; axials very numerous, sinuous and oblique; body whorl strongly and evenly rounded. tahuensis.
Whorls strongly constricted in centre.
Axials well marked over whole whorl. duplicaria.
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Axials weak on all whorls, almost obsolete on later ones. ngatapa.
Outlines of spire convex above, straight below.
Shell with numerous ribs (25 on penultimate whorl); interstices less than half width of ribs. eques.
Shell with fewer axials (20 on penultimate whorl); interstices sub-equal to axials. clifdenica.
Shell less than 6.0 mm. high.
Shell tall and well elevated.
Whorls strongly convex. arcana.
Later whorls flattish, early ones convex; axials weak, rather fine, vertical, straight. awamoana.
All whorls flattish; axials not so fine nor so weak; shell more attenuate. komitica.
Shell not markedly attenuate.
Whorls closely shouldered; axials straight, vertical; interstices as wide as axials.
Axials very numerous, fine, almost hair-like. oamarua.
Axials not so numerous, coarser. separabilis.
Spire staged; axials very weak, obsolete towards periphery. waikura.
Shell decidedly stout.
Outlines of spire straight.
Suture moderately distinct; whorls very lightly convex; axials numerous crebricostata.
Suture indistinct; whorls quite flat; shell very stout. koruahina.
Outlines of spire convex above, straight below. natales.

Turbonilla agrestis n.sp. (Figs. 1, 1a).

Shell tall, slender, outlines of spire straight; adult whorls 12 in number. Whorls swollen around posterior third causing faint, blunt nodulation of axials at their summits; sulcate around centre giving the characteristic lightly concave outline. Suture moderately distinct; whorls staged. Axial ribs (16 on penultimate whorl) coarse, rounded, straight, considerably oblique; interstices about equal in width to ribs; ribs and grooves evanescent below periphery. Entirely devoid of spiral sculpture. Protoconch decollated. Body-whorl tumid around upper third, concave over centre; periphery fairly sharply convex; base very lightly rounded, concave close in towards umbilicus. Aperture subquadrate, angled behind, broadly rounded in front; columella heavy, thick, vertical; columella-fold high up, very pronounced as a sharply raised rounded plait with a wide, deep furrow above; outer lip broken back a little.

Height (estimated), 7.6 mm. width, 1.8 mm.

Locality, McCullough's Bridge, greensands below limestone (Tahuian). Collected by Dr. H. J. Finlay.

Type (unique) in collection of Dr. H. J. Finlay.

This species is quite distinct from T. tahuensis n.sp. and T. arcana n.sp. in having sulcate whorls, straight, heavy, oblique axials, and a strong fold on the columella. In fact, it is a different style and build of shell altogether from these two early Tertiary companions.

Turbonilla pukeuriensis n.sp. (Figs. 2, 9).

Shell moderately large, of solid build, very attenuate, with 10 ½ post-nuclear whorls; outlines of spire straight. Whorls medially broadly sulcate; suture only moderately distinct, not much cut in.

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Protoconch heterostrophic, of 2 volutions coiled in a low helicoid spiral; nucleus entirely free of succeeding whorl. Axial ribs (16 on penultimate whorl) stout, thick, rounded, narrower and lower medially where whorl is sulcate; intercostal spaces about equal in width to ribs; grooves and ribs die out early below periphery of last whorl. Body-whorl concave above, swollen around periphery; base convex. Aperture subquadrate; columella straight, vertical, swollen above; outer lip straight, thick; basal lip very broadly rounded.

Height, 7.4 mm. width, 1.6 mm. (holotype).

Localities, Pukeuri (type and many shells); Rifle Butts, 1 shell; Sutherlands, South Canterbury, a number of juvenile shells having the sutures a little more cut in than is typical of shells from Oamaru localities. All are Awamoan horizons.

Type in Auckland Museum (ex writer's collection).

This species is a near relative of T. speighti n.sp., but is separable by reason of its greater attenuation, heavier and fewer axials, and sulcate whorls.

Turbonilla awamoana n.sp. (Fig. 3).

Shell tall, well elevated, of 6 ½ post-embryonic volutions, outline of spire straight. First few whorls lightly convex, later ones flattish. Suture not distinct. Axial ribs (25 on penultimate whorl) fine, not much raised, vertical, straight; interspaces subequal in width to ribs; axial ribs and grooves die out gradually just below periphery. Protoconch heterostrophic, of 2 ¼ low helicoid turns; nucleus small, not immersed in succeeding whorl. Body-whorl high, flat above, well rounded over periphery, base lightly convex. Aperture ovate to quadrate; columella vertical, arcuate, no swelling apparent; parieto-columellar junction widely rounded; basal lip narrowly rounded, rather drawn down near columella; outer lip thin, straight.

Height, 5.0 mm; width, 1.1 mm. (holotype).

Localities, Awamoa Creek (type); Target Gully shell-bed, Oamaru; Ardgowan; Pukeuri. These are all Awamoan horizons.

Type in Auckland Museum (ex writer's collection).

The weak axial sculpture of this species is reminiscent of that of T. comitas n.sp., but in the latter the axials are distinctly evanescent before reaching suture below; further, T. awamoana is a stouter shell with sutures less distinct than those of T. comitas.

Turbonilla oamarua n.sp.

Shell small, moderately attenuate, outline of spire straight; adult whorls 5 in number. Whorls very closely shouldered, flat to very lightly convex, no sulcus present; suture fairly distinct. Axial ribs (about 20 on penultimate whorl) fine, almost hairlike, about vertical, straight, slightly nodulated at summits; interstices about equal in width to axials; ribs and grooves evanescent on periphery. Spiral sculpture absent. Protoconch heterostrophe, of 2 convex turns coiled in a low helicoid spiral; nucleus entirely clear of suture of first adult whorl. Body-whorl flat to lightly convex above; periphery well rounded. Aperture ovate, moderately broadly rounded in front, angled behind; columella thin, lightly arcuate, set vertically, no fold apparent externally; outer lip straight.

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Height, 3.2 mm. width, 1.0 mm. (holotype).

Locality, shell-bed, Target Gully, Oamaru (Awamoan).

Type in Auckland Museum (ex writer's collection).

The very fine axial sculpture readily separates out this species.

Turbonilla comitas n.sp. (Fig 4).

Shell of moderate size, very attenuated, of 9 ½ post-nuclear whorls; outlines of spire straight. Whorls almost flat, exceedingly closely shouldered above and slightly bulging below. Protoconch heterostrophe, of 2 turns coiled in a low helicoid spiral; nucleus small, entirely free of succeeding whorl. Axial sculpture very weakly developed; even where developed best the corrugations are low and faint and the interstices shallow and scarcely excavated; axials of spire-whorls weaken and often evanesce before reaching lower suture, and on body-whorl they die out about or above periphery. Body-whorl long, aperture about half its length; periphery and base evenly convex. Aperture pear-shaped; columella faintly arcuate and lightly swollen above; parieto-columellar junction obtusely bluntly rounded; basal lip a little effuse to left; outer lip thin, convex (broken back a little).

Height, 5.8 mm. width, 1.2 mm. (holotype).

Locality, Target Gully shell-bed, Oamaru (Awamoan).

Type in collection of Dr. H. J. Finlay.

The obsolescence of axial sculpture and the long tapering shell make this species quite distinctive. For comparison with T. awamoana refer to remarks under that species.

Turbonilla komitica n.sp.

Shell of moderate size, attenuate, outline of spire straight; adult whorls 7 ½ in number. Whorls flattish to lightly convex; suture moderately cut in. Axial ribs (18 on penultimate whorl) not strongly elevated, rounded, straight, vertical; interspaces of rather less width than axials; ribs and grooves evanescent on periphery, which is low down on whorls. Spiral sculpture absent. Protoconch heterostrophic, not large, coiled in a low helicoid spiral. Body-whorl flattish above, convex over periphery, lightly rounded on base. Aperture rather quadrate, moderately broadly rounded in front; columella arcuate, set vertically, a distinct fold present just below its insertion; outer lip broken.

Height, 5.7 mm. width, 1.2 mm.

Locality, Pakaurangi Point beds, Kaipara (Hutchinsonian).

Type in collection of Auckland University College. Discovered by Professor J. A. Bartrum.

The more attenuate habit and lack of convex early whorls distinguish this form from T. awamoana, its nearest ally.

Turbonilla tahuensis n.sp. (Fig. 10).

A moderately large shell with 10 post-nuclear whorls, which are regularly convex and a good deal broader than they are high. Protoconch heterostrophic, of at least 2 helicoid turns; nucleus loosely coiled, greatly protruding and overhanging first adult whorl. Axials very numerous (28 on penultimate whorl), rounded, flexuous,

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oblique; interspaces about equal in width to axials, which are evanescent below the rounded periphery. Base lightly convex, running in rapidly to axis of shell, concave in region of umbilical furrow. Aperture broadly subquadrate, widely angled behind, broadly rounded in front; outer lip broken back; inner lip not callused; columella straight, thin, almost vertical, no fold apparent.

Height, 8.8 mm. width, 2.4 mm.

Locality, McCullough's Bridge, greensands below limestone (Tahuian). Collected by Dr. R. S. Allan.

Type in collection of Dr. H. J. Finlay.

This is the shell listed by Allan (Trans. N.Z. Inst., vol. 57, p. 291; 1927) under the manuscript name T. tahuensis. It differs from all other Neozelanic species in the peculiar coiling of the lateral nucleus, and the numerous flexuous, oblique axials are quite distinctive.

Turbonilla arcana n.sp. (Fig. 5).

A tall, fragile, tapering shell with about 10 adult whorls, all evenly and distinctly convex, so that the suture is well cut in; suture quite oblique; outline of spire straight. Apex missing. Axial ribs (about 19 on penultimate whorl) a little flexuous, about vertical, thin, fairly sharply raised and about twice their own width apart; axials extending on to base of shell; intercostal spaces dying out gradually below periphery. Last whorl convex, base flatly convex, but concave towards columella; aperture broken back, but almost certainly ovate; columella arcuate, thinning below and with a slight swelling above; parieto-columellar junction broadly rounded.

Height (estimated), 5.5 mm. width, 1.0 mm.

Locality, Waihao Downs greensand (Bortonian).

Type in collection of Dr. H. J. Finlay.

Separable from T. tahuensis by much greater slenderness, smaller size and fewer, less flexuous, sharper and more distant axials.

Turbonilla crebricostata Marwick (Fig. 6).

1931. Turbonilla (Pyrgiscus) crebricostata Marwick, N.Z. Geol. Surv. Bull., no. 13, p. 107, fig. 207.

This species is founded on a single specimen with the protoconch and early adult whorls decollated. In his description Marwick correctly states that there is no spiral sculpture, and his reference to Pyrgiscus therefore cannot be maintained. The adult characters are in all respects those of Turbonilla s.str.

Height (estimated), 5.0 mm. width, 1.6 mm.

Locality, N.Z.G.S. loc. 1294 (N.Z. Geol. Surv. Pal. Bull., no. 13, p. 37; 1931), Gisborne District (Hutchinsonian).

Type in collection of N.Z. Geological Survey, Wellington.

Turbonilla speighti n.sp. (Fig. 7).

Shell large, attenuated, of fairly heavy build and possessing 9 post-embryonic whorls; outlines of spire straight; suture not very distinct; whorls tightly clasping, flat, but with a slight bulge below on later ones. Protoconch heterostrophic, markedly exsert, of 2 ¼ low helicoid volutions; nucleus small and separated from suture of first

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adult whorl by a distance about equal to its own diameter. Axial sculpture of strong, straight, vertical, rounded ribs (18 on penultimate whorl), the interspaces rather narrower than the ribs. Axial and intercostal spaces evanescence usually about periphery of body-whorl, but sometimes slightly above. In several specimens rather strong axial growth-striae are present on the base. Body-whorl rather high, twice height of aperture, straight above, well rounded over periphery, convex on base. Aperture subquadrate; columella thick, straight, vertical, swollen just below its insertion; parieto-columellar junction obtusely rounded; basal lip well rounded; outer lip antecurrent to suture, straight below that.

Height (holotype), 7.5 mm. width, 2.0 mm. A paratype: corresponding dimensions, 11.8 mm. 2.9 mm.

Localities, Blue Cliffs, South Canterbury (type), sandy clays above limestone (Hutchinsonian); blue sandy clays, foot of Mount Horrible, Pareora Gorge, South Canterbury (same horizon as Blue Cliffs); Mahoenui beds, road-cutting 1 mile east of tunnel at north end of Awakino Gorge (Hutchinsonian).

Type in Auckland Museum (ex writer's collection).

This is the commonest Turbonillid in the beds at Blue Cliffs. It comes closest to T. pukeuriensis n.sp., but is less slender, has not the sulcate whorls of pukeuriensis and grows to a larger size. For comparison with T. awasimulans, to which it bears a strong resemblance, see remarks under that species. The shell from the Mahoenui beds is a perfect match of those from the type-locality.

Turbonilla separabilis n.sp. (Fig. 8).

Shell small, rather slender, outlines of spire straight; adult whorls 6 ½ in number. Whorls closely shouldered, flat to very lightly convex, bulging slightly below, a faint suggestion of sulcus between axials on upper third; suture fairly distinct. Axial ribs (16 on penultimate whorl) thin, straight, vertical; interstices about equal in width to axials; ribs and grooves evanescent about or just below periphery. Spiral sculpture lacking. Protoconch heterostrophic, of 2 convex turns coiled in a low helicoid spiral, lower edge of nucleus tangent to suture of first adult whorl. Body-whorl flat above with well-rounded periphery and lightly convex base. Aperture ovate rather, angled behind, effuse in front; columella thin, rather arcuate, set vertically; columella-fold indicated by a low, broad swelling high up; outer lip straight.

Height, 4.0 mm. width, 1.0 mm. (holotype).

Localities, Target Gully shell-bed, Oamaru (type and many paratypes); Sutherlands, South Canterbury; Holme Station, Pareora Gorge, South Canterbury. These are all Awamoan horizons.

Type in Auckland Museum (ex writer's collection).

This species is smaller than T. speighti, and has closer and finer sculpture. It somewhat resembles T. awamoana, but has fewer axials with wider interstices, and lacks the rather overhanging whorls of that species. T. comitas is a much more acicular shell with weak to obsolete axial ribs.

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Turbonilla awasimulans n.sp. (Fig. 11).

Shell of moderate size, elongate-conic, of 8 ½ post-nuclear whorls; outlines of spire straight over anterior two-thirds, rather more rapidly converging to apex on posterior third. Early adult whorls convex with sutures distinct and well cut in; later one flattish with a slight supra-sutural tumidity and sutures less distinct. Axial ribs (about 22 on penultimate whorl) not strong, vertical, straight, separated by interspaces whose width is less than that of the ribs; ribs and grooves evanescent at about periphery of last whorl, though in some instances they are seen lower down on the base. Protoconch heterostrophic, of about 2 volutions, the nucleus small and just clear of immersion in first adult whorl. Body-whorl flat below suture, rather bulging and strongly convex at periphery, base very lightly convex to flat. Aperture subquadrate, angled behind, broadly and rather squarely rounded in front; columella strong, straight, vertical, distinctly swollen just below insertion; parieto-columellar junction obtusely angled; outer lip straight, vertical.

Height, 6.5 mm. width, 1.7 mm. (holotype).

Localities, Pukeuri (type); Target Gully shell-bed; Ardgowan shell-bed. These are all Awamoan horizons near Oamaru.

Type in Auckland Museum (ex writer's collection).

This species has not the strongly sulcate whorls of T. pukeuriensis. It comes close to T. speighti, from which it is separable, however, by the convex outline of its early adult whorls and weaker development of axials. Further, T. speighti has its earlier whorls narrower and higher, so that the apical region has a much less massive appearance than that of T. awasimulans.

Turbonilla eques n.sp. (Fig. 24).

Shell of moderate size, elongate-conic, with a wide fawny coloured band around whorls just below middle; of 9 ½ post-nuclear whorls; outline of spire convex over upper fourth, thereafter straight. Whorls very lightly convex, some almost flat, constricted a little to suture below. Protoconch heterostrophic, considerably oblique, somewhat bulbous, of several turns in a very low helicoid spiral; nucleus about one-half immersed. Axial ribs (about 25 on penultimate whorl) narrowly rounded, vertical, straight, a little pinched in at upper third of length on some specimens giving the impression of a faint intercostal sulcus; width of intercostal spaces about half that of axials; ribs and grooves dying out gradually below periphery, and ribs faintly seen extending towards umbilical region. Body-whorl convex. Aperture sub-oval; columella arcuate, set vertically, lightly swollen above; parieto-columellar junction rounded, drawn down; outer lip straight, vertical.

Height, 7.6 mm. width, 1.8 mm. (holotype).

Localities, Poor Knights Islands, in 60 fathoms (type); Hen and Chickens Islands, in 25 fathoms (Recent).

Type in collection of Dr. H. J. Finlay.

The two shells from Hen and Chickens Islands are rather stouter than those from Poor Knights, but otherwise agree closely.

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Turbonilla clifdenica n.sp. (Fig. 20).

This shell is extraordinarily close to the preceding one, especially as regards shape of whorl, outline of spire and features of aperture. Undoubtedly the present species is a direct ancestor of T. eques. But eques is a smaller species with wider early post-nuclear whorls, more oblique and less exsert protoconch with nucleus partly immersed, that of clifdenica being clear of the suture. Further, clifdenica carries fewer and heavier axials per whorl, about 20 on the penultimate whorl as against about 25 on the corresponding whorl of eques; the interstices are sub-equal in width to the ribs, and therefore relatively wider than those of eques, and the whorls more definitely sulcate about upper third or fourth.

Height, 9.8 mm. width, 2.0 mm. (holotype).

Locality, Clifden, Southland, bed 4 on east side of Waiau River = band 6C on west side (type); also band 6C.

Type in collection of Dr. H. J. Finlay.

Turbonilla waikura Marwick (Fig. 23).

1931. Turbonilla waikura Marwick, N.Z. Geol. Surv. Pal. Bull., no. 13, p. 107, fig. 203.

The most striking features of this species are the staged whorls, well shouldered at top, and the very weak axial ribs. The embryo is large, globose and well tilted. Its nucleus is almost completely immersed. The weak ribs, strong shoulder, much lighter convexity of whorl and rounded periphery easily distinguish this species from T. ngatapa Marwick, its nearest relative.

Height, 3.2 mm. width, 1.0 mm. (holotype).

Locality, Ihungia beds, Waikura Stream, Patutahi, Gisborne District, N.Z.G.S. loc. 1342 (Hutchinsonian).

Type and two paratypes in collection of N.Z. Geological Survey, Wellington.

Turbonilla ngatapa Marwick (Fig. 17).

1931. Turbonilla ngatapa Marwick, N.Z. Geol. Surv. Pal. Bull., no. 13, p. 106, figs. 201, 202.

The two specimens of this species have the earliest whorls decollated, but the build of shell and development of axial structure is so much akin to that of T. waikura, which has a low helicoid embryo, that one cannot hesitate to refer them to the same genus. The columella-fold of ngatapa is unusually strong for a Turbonillid species.

Height (estimated), 6.7 mm. width, 1.75 mm. (holotype).

Localities, tuffaceous arenaceous mudstone, Ngatapa, Gisborne District, N.Z.G.S. loc. 1340 (type); Ihungia beds, Waikura Stream, Patutahi, Gisborne District, N.Z.G.S. loc. 1342 (Hutchinsonian).

Type and a paratype in collection of N.Z. Geological Survey, Wellington.

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Turbonilla duplicaria Marwick (Fig. 22).

1931. Turbonilla duplicaria Marwick, N.Z. Zeol. Surv. Pal. Bull., no. 13, p. 107, fig. 205.

This is a larger and stouter shell than either of the foregoing, to which it is obviously related, as shown by build of shell, shape of whorl and nature of axials. The embryonic and earlier post embryonic whorls are absent, but the characters noted above obviously point to a location along with T. ngatapa and T. waikura. The whorls are strongly concave, suture strongly impressed, axials numerous, well defined, and spaced less than their own width apart.

Height, about 6.0 mm. width, 1.8 mm.

Locality, south bank, Waikohu River, Gisborne District, N.Z.G.S. loc. 1290, Ormond Series (Taranakian).

Type (unique) in collection of N.Z. Geological Survey, Wellington.

Turbonilla macies n.sp. (Fig. 15).

Shell moderately large, probably very attenuate, but the specimen is incomplete, only the last 5 whorls remaining; outlines of spire straight. Whorls sulcate at upper third; above that and bordering suture there is a swollen band on which the axials acquire a faint nodulation. Suture well impressed, distinct, situated below periphery. Protoconch missing. Axial ribs somewhat weaker on last two whorls, but never very pronounced; low, narrow, rounded, straight, descending distinctly obliquely to right; 21 ribs on penultimate whorl; intercostal spaces wider than ribs; ribs and grooves becoming evanescent early on base. Body-whorl shouldered at suture, below that concave; periphery strongly convex; base lightly convex. Aperture roundly oval; callus of inner lip spread widely; columella and basal lip partly broken away; outer lip trending in same direction as the oblique axial ribs.

Height (probable), 9.0 mm. width, 1.7 mm.

Locality, Clifden, Southland, band 6B (Hutchinsonian).

Type (unique) in collection of Dr. H. J. Finlay.

This species is referred to Turbonilla Group A in the meantime on account of its similarity in general build of whorl to T. duplicaria. It is readily separable from duplicaria by reason of its considerably greater attenuation, weaker and more oblique axials. The convexity of the whorl is higher up, less deep and not so wide.

Turbonilla natales n.sp. (Fig. 19).

Shell small, conic, solidly built, of 6 post-nuclear whorls; outlines of spire faintly convex. Whorls with a prominent tumid band below suture, the axials in surmounting it being nodulated; below this the whorl is concave, thereafter swelling out again before being constricted to suture; suture distinct, impressed. Protoconch low, well tilted, heterostrophic, low helicoid; nucleus about one-half immersed in succeeding volution. Axial ribs (17 on penultimate whorl) distinct, well raised, rounded, straight, vertical, nodulated on subsutural swelling; intercostal spaces of same width as axials; axials and grooves dying out on base well below periphery. Body-whorl

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and apertural characters almost identical with those of T. duplicaria Marwick, except that the sub-sutural swelling and nodulation of axials are stronger and the concavity of whorl shallower. There is a fold on the columella just below its insertion.

Height, 4.0 mm. width, 1.4 mm. (holotype).

Locality, Clifden, Southland, east side of river, bed A (type), and bed C; band 6C on west side of river.

Type in Auckland Museum (ex writer's collection).

This species is a very close ally of T. duplicaria, from which it is distinguished by being smaller and in having a heavier sub-sutural tumid band, and stronger nodules at summits of axial ribs. The whorls are not so deeply concave and do not swell below as strongly as those of T. duplicaria before constricting to suture. T. macies is a considerably more elongate shell, and has not the strong tuberculate axials; also the axials are fainter and oblique, not vertical, as in natales.

Turbonilla koruahina n.sp.

There is a single shell of very distinctive habit, but in the absence of the protoconch no close generic distinction can be made. It is of heavy build, notably stouter than other Neozelanic species of Turbonilla, has whorls quite flat, and suture indistinct. The surface is considerably rubbed; the axials appear broad and low and are separated by interstices which, are narrower than the costae. Aperture quadrate.

Height (estimated), 4.3 mm. width, 1.8 mm.

Locality, Kaawa Creek beds (Waitotaran).

Type (unique) in collection of Auckland University College.

This is the “Turbonilla n.sp. B” of the Kaawa Creek Pyramidellids listed by the writer in The Waitotaran Faunule at Kaawa Creek (Trans. Roy. Soc. N.Z., vol. 66, p. 112; 1936).

Turbonilla n.sp. aff. speighti n.sp.

Only fragmentary specimens are available. They are more-tapering than speighti, and have the whorls more bulging below and the axials not so heavy.

Localities, Ardgowan; Sutherlands (Awamoan horizons).

Group B.—Nuclear Character Planorboid (Paucispiral).

This division embraces the following genera:—

  • Turbonilla B of this paper.

  • Chemnitzia B of this review.

  • Taurangia n.gen.

  • Striarcana n.gen.

  • Planpyrgiscus n.gen.

  • Gispyrella n.gen.

Turbonilla Group B.

Here are located shells agreeing with Turbonilla A in all respects save that the embryo is of planorboid type (paucispiral and with large excentric nucleus).

Picture icon

Figs. 1, 1a.—Turbonilla agrestis n.sp. holotype Fig. 2.—Turbonilla pukeuriensis n.sp; holotype. Fig. 3.—Turbonilla awamoana n.sp., holotype. Fig. 4.—Turbonilla [ unclear: ] n.sp. holotype. Fig. 5.—Turbonilla arcana n.sp. holotype. Fig 6.—Turbonilla crebricostata Marwick; holotype. Fig. 7.—Turbonilla pukcuriensis n.sp. holotype. Fig 8.—Turbonilla [ unclear: ] n sp. holotype. Fig 9.—Turbonilla pukcuriensis n.sp., juvenile paratype. Fig. 10.—Turbonilla tahuensis n.sp. holotype. Fig. 11.—Turbonilla awasimulans n.sp. holotype. Fig 12.—Turbonilla [ unclear: ] n.sp. holotype. Fig. 13.—Turbonilla suteri Powell; holotype. (All figures × 10, with the exception of Fig. 1a.)

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Fig 14.—Turbonilla harodlt n.sp. holotype. Fig. 15.—Turbonilla macies n.sp. holotype. Fig. 16—Turbonilla moorei n.sp. holotype. Fig. 17.—Turbonilla ngatapa Marwick; holotype. Fig. 18.—Turbonilla clifdenica n.sp. holotype. Fig. 19.—Turbonilla natales n.sp. holotype. Fig. 20.—Turbonilla clifdenica n.sp. holotype. Fig. 21.—Turbonilla erratica n.sp. holotype. Fig. 22.—Turbonilla duplicaria Marwick; holotype. Fig. 23.—Turbonilla waikura Marwick; holotype. Fig. 24.—Turbonilla eques n.sp. holotype. (All figures × 10, with the exception of Fig. 21, which is enlarged 13 times.)

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Key to Species of Turbonilla B.

Whorls convex.
Shell large.
Axials about 22 on penultimate whorl.
Axials sharply raised, flexed anteriorly above suteri.
Axials low, wide; interstices much narrower than axials; axials weaker on anterior part of whorl. moorei.
Axials wide, not low; interstices narrower; axials of equal strength over whole whorl. haroldi.
Axials 14 on penultimate whorl; intercostal spaces wide. stoneleighana.
Shell very small.
Axials 17 on penultimate whorl; heterostrophic part of protoconch of three-quarters of a turn erratica.
Whorls nearly flat or only lightly convex; axial ribs dying out above periphery, weak. bexleyana.

Turbonilla moorei n.sp. (Fig. 16).

Shell large, elongate-conic, semi-transparent, of 8 post-nuclear whorls, all strongly and regularly convex; outlines of spire straight. Suture well cut in and distinct. Protoconch prominent, heterostrophic, of about 1 ¼ planorboid volutions; nucleus considerably immersed. Axial ribs (23 on penultimate whorl) broad, moderately heavy, straight, vertical, extending across entire whorl; intercostal spaces narrower than ribs; grooves and axials dying out gradually at about periphery of body-whorl or a little below. Body-whorl strongly and regularly convex from suture to base. Aperture broadly ovate; columella practically straight, vertical, pillar-swelling hardly distinguishable; parieto-columellar junction rounded; basal lip broadly rounded; outer lip straight, vertical.

Height, 7.5 mm. width, 2.4 mm. (holotype).

Locality, off Otago Heads, in from 40–70 fathoms, many “dead” shells (Recent).

Type in writer's collection.

This and the following three species are undoubtedly all on the same line of evolution and form a very compact little assemblage characterised by a close similarity of build of shell, shape of whorl and of features of embryo. The characters differentiating these species are quite definite and allow a ready separation. The specimens of T. haroldi from 50 fathoms off Oamaru are all constantly separable from the Otago Heads shells in having considerably fewer and sharper axials. Suteri resembles stoneleighana in its less attenuate, rather stumpy habit, and is further separable from haroldi (which it resembles in its somewhat sharply elevated axials) by reason of the strong antecurrent twist of its axials towards their posterior extremities. Stoneleighana and moorei both have broad axial ribs separated by narrower interstices, but in the former the protoconch is much less exsert, the axials tend to die out just above sutures, and the early adult whorls are wider in relation to height than are those of moorei, thereby giving the shell a characteristically more thick-set, less attenuate appearance.

This species is named in honour of Mr. J. A. Moore, M.A., B.Sc., Principal of the Teachers' Training College, Dunedin.

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Turbonilla suteri Powell (Fig. 13).

1924. Turbonilla suteri Powell, Reo. Cant. Mus., vol. 3, pt. 1, p. 47.

This is a very fine and quite distinctive species. The axial ribs and grooves die out early below periphery. Powell's figure represents the axial sculpture as ending abruptly at the periphery of last whorl. Actually this is not strictly so, for, though the grooves die out quickly, yet there is not the sudden cessation at a vertical escarpment as in Chemnitzia.

It is on a quite different line of Turbonilla from any of the Miocene species, but has several Recent Forsterian relatives and a Pliocene one from Hawke's Bay. At first sight it is reminiscent of T. tahuensis from McCullough's Bridge, Waihao Downs, a Tahuian (Eocene) species, to which it bears a striking resemblance. Though tahuensis is typically larger, yet the shape of whorls and nature of axial sculpture are quite similar in character to those of the Recent species. These two species differ widely, however, in embryonic features, for tahuensis possesses a very strongly projecting and overhanging nucleus, while T. suteri has a nucleus of planorboid type.

The type is the only specimen the writer has examined, and the nuclear whorls are decollated; but closely related species from off Otago Heads possess a planispirally coiled embryo, and for this reason suteri is located along with them.

Height (estimated), 5.5 mm. width, 2.0 mm.

Locality, Resolution Island, Dusky Sound, in 80 fathoms (type); 60 miles east of Lyttelton, in 100 fathoms (A. W. B. Powell). Recent. Type in collection of Mr. A. W. B. Powell, Auckland.

For comparison with related species see remarks under T. moorei.

Turbonilla haroldi n.sp (Fig. 14).

Shell of moderate size, elongate-conic, probably semi-transparent when fresh, of 7 ½ post-embryonic turns; outlines of spire straight. Whorls strongly and regularly convex, no shoulder; suture well cut in and distinct. Protoconch moderate in size, heterostrophic, of about 1 planorboid volution; nucleus apparently large, almost totally immersed and laterally situated. Axial ribs (14 on penultimate whorl) prominent, heavy, the base of each spread rather widely, the summits a little sharpened; the axials are straight and vertical on whorls of spire, slightly flexuous on last whorl. Intercostal spaces rather wider than ribs. Ribs and grooves dying out near periphery, not ending abruptly. Body-whorl and apertural characters the same as for T. moorei.

Height, 6.4 mm. width, 2.1 mm. (holotype).

Locality, off Oamaru, in 50 fathoms (Recent).

Type in collection of Dr. H. J. Finlay.

Of the two species, moorei and haroldi, there are quite a number of specimens, 35 of the former taken off Otago Heads, and 8 of haroldi taken off Oamaru. The nearness of these two localities to each other would lead one to expect to find the same species ranging into each, but the sets of shells from the two stations are each quite constant in themselves and obviously distinct. This corroborates

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what has been noticed in regard to certain other Turbonillids, viz., that the range of distribution often is quite circumscribed, and that generally the Neozelanic species are not wide-ranging. So that it is possible that the two decorticated shells identified by Powell (Rec. Cant. Mus., vol. 3, no. 1, p. 47; 1926) as T. suteri at the time of his description of that species, are in reality one of the new forms under consideration.

For comparison of T. haroldi with related species refer to remarks under T. moorei.

Turbonilla stoneleighana n.sp. (Fig. 12).

Shell of moderate size, of solid build, elongate-conic, of 6 post-nuclear whorls; outlines of spire straight. Whorls convex; suture distinct. Protoconch large, bulbous, heterostrophic, of about 1 plan-orboid volution; nucleus almost wholly immersed; degree to which embryo as a whole is exsert rather variable. Axial ribs (about 22 on penultimate whorl) coarse, rounded, vertical, but not strongly ridged up; intercostal spaces not deep, less in width than the ribs; ribs and grooves die out usually just above periphery of whorls. Body-whorl strongly and regularly convex from suture to base. Aperture pyriform; columella with a very low swelling above, straight, vertical, reflexed; parieto-columellar junction angulated; basal lip narrowly rounded and drawn down; outer lip straight to lightly convex.

Height, 5.9 mm. width, 2.0 mm. (holotype).

Locality, Petane, Hawke's Bay (Nukumaruan).

Type in collection of Dr. H. J. Finlay.

For comparison with related species refer to remarks under T. moorei.

The two following species are on different lines from the foregoing ones of Turbonilla Group B:—

Turbonilla erratica n.sp. (Fig. 21).

Shell very small, elongate conic, of 6 ¼ post-nuclear volutions; outlines of spire straight. Whorls evenly but not strongly convex; suture below periphery, impressed. Protoconch heterostrophic, planorboid, prominent, of ¾ of a volution; nucleus large, about one-half immersed, not central. Axial ribs (about 17 on penultimate whorl) rounded, vertical, straight; width of interspaces sub-equal to that of ribs; ribs and grooves die out early below periphery of last whorl. Body-whorl lightly convex above; periphery well rounded; base lightly convex. Aperture sub-oval; columella vertical, a little arcuate; parieto-columella junction rounded; basal lip regularly rounded; outer lip straight, vertical; columella-fold not apparent.

Height, 3.0 mm. width, 0.8 mm. (holotype).

Locality, Pukeuri, Oamaru (Awamoan).

Type in collection of Dr. H. J. Finlay.

The small size, lightly convex whorls and protoconch distinguish this species from its associates in Turbonilla B.

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Turbonilla bexleyana n.sp. (Fig. 18).

Shell small, rather stout and heavy of build, elongate-conic, of nearly 6 post-nuclear volutions; outlines of spire straight. Whorls very flatly convex; suture below periphery, only moderately well defined. Protoconch large, considerably tilted, heterostrophic, planispiral; nucleus one-half immersed. First post-nuclear whorl wide and heavy-looking. Axial ribs (about 18 on penultimate whorl) straight, vertical, very weak, low, rounded; dying out above periphery of whorls; grooves shallow, also gradually evanescent above periphery, their width sub-equal to that of ribs. Body-whorl straight above, rounded over periphery, convex on base. Aperture broken; columella thick, vertical, straight; columella-fold when seen externally only a low swelling, but more ridged within; outer and basal lips broken away.

Height, 3.7 mm. width, 1.1 mm.

Locality, argillaceous beds, 20 chains upstream from mouth of Bexley Creek, Awakino Gorge, and below the Mahoenui Limestone. Mahoenui Series (Hutchinsonian).

Type in writer's collection.

Distinct in its large, tilted protoconch, heavy early whorls of spire and its weak axial ribs dying out above periphery.

Turbonilla cf. stoneleighana n.sp.

There is a single specimen with the top of the spire decollated. The general build and shape of whorl, character of suture and nature of axial are strongly reminiscent of stoneleighana from the Pliocene of Hawke's Bay.

Locality, Kaawa Creek beds (Waitotaran).

Specimen in collection of Auckland University College.