Tertiary Mollusca from Dannevirke Subdivision.

By C. A. Fleming.
N.Z. Geological Survey.

towards the middle of shell. Umbones at anterior fourth. Hinge plate and teeth relatively much more massive than in purpurata of same size.

Dimensions (Holotype, right valve); Length, 28·25; height, 24·25; thickness (1 valve), 11 mm.

Locality: 2314, Takapau (N.W.) S.D. (Waitotaran.) Holotype and many paratypes.

Many of the larger specimens, including the holotype, have their rectangular shape accentuated by a senile growth inwards of the periphery of the shell, but the characteristic shape is present in all but one of the 30 specimens examined (including young shells). The exception is higher than the rest but shares their characteristic sculpture. The shape recalls rienga (Powell), but this has a very much weaker hinge and wider ribs with narrower interspaces. V. purpurata and purpurata difficilis have a weaker hinge plate, more ovoid shape, and lack the marked inequality of the posterior ribs.

Named after Dr. A. B. Lillie, N.Z. Geological Survey.

Tellinidae.

Barytellina tertia n.sp. (Plate 28; Figs. 3, 4.)

Shell large for genus, ovate, more elongated and less circular than most B. anomalodonta Finlay, but not so long as genotype; less inflated than either of these species. Sculpture decorticated but apparently similar to anomalodonta. The posterior radial ridge which runs from the umbo to the posterior end is less pronounced than in either of the named species, and is a simple fold, without the delimiting groove and narrow ridge that bound it in crassidens. The posterodorsal margin of the shell is straight, not convex as in the other species, and is not turned in towards the hinge as in anomalodonta. Hinge and teeth stronger than in genotype but weaker than equal sized anomalodonta. Right valve with ungrooved posterior cardinal, and lamellar anterior cardinal which is not so obliquely oriented as in the other species. Dentition otherwise similar but closer to anomalodonta.

Dimensions: (Holotype, right valve); length, 27·25; height, 20·5; thickness, 5·5 mm. (Paratype, left valve); length, 33; height, 25 mm.

Locality: 2324, Takapau (N.E.) S.D. Petane Series.

Veneridae.

Kuia macdowelli Marwick.

Shells which cannot be separated from topotypes of this species occur at a number of localities in southern Hawke's Bay at a considerably higher horizon in the Tertiary than the type locality and other quoted localities. The Dannevirke specimens come from rocks mapped as Tutamoe, Mapiri and even Opoiti Series—i.e., up to the lower Pliocene. Specimens reach a length of 56 mm., height 46 mm., thickness (2 valves) 33 mm.

Dosinia (Raina) macroptera n.sp. (Plate 28; Figs. 8, 9.)

Shell of moderate size, thin for sub-genus, not highly inflated but flattened, especially around margins. Subcircular, produced intoconspicuous wings both anteriorly and posteriorly. Dorsal margin

behind beaks moderately arched; in front of beaks deeply concave above the wing, so that the raised lunule is visible from a side view. Lunule well defined, long, impressed marginally and pouting medially. Escutcheon moderately deep, more so on left valve. Sculpture of low, irregular, and flat topped, concentric lamellae, continuous from lunule to escutcheon, overlapping the interspaces from above and bounded distally by fine grooves. Interspaces wide and flat, sculptured by fine concentric growth lines.

Dimensions (Holotype): Length, 54; height, 46; thickness, (2 valves) 25 mm.

Locality: 2746, Te Uri Road, Mangaotoro (N.E.) S.D. (Tongaporutuan?)

The subgeneric allocation is tentative as hinge details are not available. The “lucinoid” wings, flattened shell, and sculpture distinguish this from all other species in the subgenus. The sculpture of raised lamellae allies it to Dosinia cottoni Marwick. A para-type of the latter species has now been excavated to expose the hinge which shows that the species is a Raina and not a Kereia as described.

Emarginulidae.

Tugali kumeroa n.sp. (Plate 28; Figs. 6, 6a.)

Shell of moderate size, smaller than Castlecliffian pliocenica Fin., larger than bascauda; moderately high and compressed, sides converging towards the front. Apex somewhat hooked, more anteriorly placed than in pliocenica of same size. Dorsal carina not conspicuously raised, but unique in that the original single sinus rib breaks into four riblets of about equal size, which run to the margin without developing secondary threads. This appears due to the almost immediate bifurcation of the central of three ribs, suggesting that the species belongs to the pliocenica-superba-elegans lineage, rather than to the bascauda line. Other radials fewer in number than in pliocenica especially behind, where they are coarser and the concentric threads stronger and more continuous over the radials, less beaded at the intersections. Internal marginal crenulations fewer and weaker than in pliocenica.

Dimensions: Length, 16; width, 10; height, 11 mm.

Locality: 2687 (high in Lower Nukumaruan) Tahoraite (S.W.) S.D., near Kumeroa.

The quadruple division of the carina distinguishes this from all other New Zealand species and suggests a way in which the three-ribbed and two-ribbed groups might be connected phylogenetically.

Trochidae.

Coelotrochus browni n.sp. (Plate 28; Fig. 5.)

Very similar to C. tiaratus (Q & G.). Whorl shape and spire angle the same, differing in finer sculpture. Below the suture, which as in tiaratus, is slightly impressed and lies immediately beneath the periphery, there is a moderately strong, nodulous, spiral thread; under this are 10 fine, beaded, and spaced threads of equal strength down to the periphery; basally the same sculpture continues with 11 more fine beaded threads. In tiaratus the same number of spirals

may be counted on spire whorls, above the periphery, but they are usually fewer (6–8) and always stronger; when 10 threads occur it is due to interposition of finer threads between the strong ones.

Dimensions: Height, 11; diameter, 16 mm.

Localities: 2380 (type) Takapau (S.E.) S.D., 390 feet above base of Petane Series. 1198 argillaceous sandstone, 10 feet thick, below boulder band and immediately above coal; coast between Ototoka (= Butler's) Creek and Okehu Creek.

Calliostomatidae.

Maurea correlata n.sp. (Plate 28; Fig. 7.)

This species is described from fragmentary material on account of its significance stratigraphically. Shell small for the genus, of similar shape and appearance to the mid-Tertiary species, suteri and fragilis. Spire tall, slightly concave in outline. Earliest whorls missing. Sculpture of four spiral threads with no interstitials. The uppermost (subsutural) and the lowest (peripheral) spirals are moniliform and strong, the two medial threads are weaker and equidistant between the others. The subsutural thread is separated from the suture by a smooth area about half the width of the smooth interspaces between the other three threads and is divided into regular beads, 2 per millimetre on the body whorl. The peripheral thread is similarly beaded, and shows a tendency to divide into two threads on later whorls. The medial threads are distinct, slightly rounded, and on the body whorl tend to be indistinctly beaded. Base enclosed in hard matrix.

Dimensions: Height (actual), 15; diameter, 10·5 mm.

Locality: 2731, Mangaotoro (N.W.) S.D. (type), below Paeroa Trig. (Opoitian.) 153, Callaghan's Creek, Waimea S.D., “Westland. (Opoitian.)

This form appears to be the last representative of Miocene lineages rather than a precursor of Pliocene-Recent forms. It comes from a shell limestone that overlies mudstones with Urenuian microfauna and is the base of the Pliocence sequence. Associated mollusca are Callusaria aff. obesa (Marwick), Zelandiella pliocenica Powell, Olivella neozelanica (Hutton), Antisolarium cf. egenum (Gould), and cf. stoliczkai (Zitt.), Tanea aff. socia (Finlay), Polinices cf. waipipiensis (Marwick), and two new species of Baryspira. The other occurrence, a greensand, an the Westland Blue Bottom, has a similar stratigraphic relationship, above Taranakian and below Pliocene beds. Here the associated species include Sectipecten wollastoni (Hutton), Cucullaea n.sp. aff. australis (Hutton), Polinices cf. waipipiensis, cf. propeovatus (Marwick), Austrofusus tuberculatus Marwick, Olivella neozelanica (Hutton).

Eratoidae.

Proterato pliocenica n.sp. (Plate 29; Fig. 10.)

Shell moderate sized for the family. Pyriform, marginelloid, smooth externally. Spire well developed, concave sided, sutures indistinct. Lip thickened within but not externally, projecting posteriorly and running up on to the spire as a weak callus. Aperture narrow, parallel sided, opening at a wide, shallow anterior canal.

Outer lip armed with 13 denticles confined to the aperture. Fossula broadly convex and shallow; terminal ridges, two, moderately strong, separated by a groove of equal width; parietal wall, badly decorticated, but showing traces of small denticles of which three remain, the most posterior half-way up the aperture.

Dimensions: Height, 9.5, width 6 mm. (unique holotype).

Locality: 2314, Takapau S.D. Waitotaran (calcareous sandy mudstone facies).

In spite of the badly decorticated state of the specimen the interest of the occurrence of a species of the Eratoidae in the Waitotaran justifies its description, for the family has not previously been recorded later than Awamoan in N.Z. The generic location is made with some hesitation from figures and descriptions. Its nearest ally in New Zealand appears to be an undescribed species from Awamoa Creek. The number of denticles on the outer lip is uncertain, as the distal ones are damaged.

Cymathdae.

Cabestana manawatuna n.sp. (Plate 29; Fig. 17.)

Apparently akin to the C. waterhousi group (including debilior, Finlay), and closest to debilior, but more slender, with axial sculpture even more obsolete. Protoconch lost. Sculpture on earliest whorls of six beaded spiral threads, of which two, the second and fourth above suture, are strongest. About 11 low, ill-defined axial cords per whorl cross the spirals and form at the intersections sharp, ridge-like nodules, elongated spirally. On later whorls bifurcation of spirals occurs until there are 11 on the penultimate; the two chief spirals become doubled and retain their importance. On the body whorl there are about 25 spirals, some doubled and some with fine interstitials. Radials almost absent from the body whorl and represented only by a nodular development of the two chief spirals. Varices absent from first four whorls, three on later whorls, high and narrow, with spiral sculpture continuous over them without interruption. Beak long and slightly twisted. Outer lip missing; inner lip with two obliquely placed anterior denticles on parietal callus and six plaits on column.

Dimensions (unique holotype): Height, 50; diameter (without varix), 19 mm.

Locality: 2492, Tahoraite (S.W.) S.D. Lower Nukumaruan.

If this species is truly of the same group as waterhousi segregata Powell and debilior Finlay it puts back the arrival of this group of Cymatiids in New Zealand seas at least to the Nukumaruan, but waterhousi segregata Powell is obviously a more recent derivative of the Australian stock.

Cassididae.
Genus Xenophalium Iredale, 1927.

Mitridae.

Austromitra quennelli n.sp. (Plate 29; Fig. 12.)

Shell of moderate size for genus. Protoconch, two whorled, assymmetrically helicoid, without sculpture. Spire whorls with almost vertical sides, the penultimate more convex and contracted towards the suture. All whorls shouldered flatly below the undulating suture. Body whorl expanded and convex above, contracted sharply below into the somewhat twisted neck. Spiral sculpture weak; a fairly marked cord at shoulder angle on younger whorls (stronger on paratype than on holotype) and many fine irregularly spaced grooves on shoulder and periphery. Axial sculpture strong; 12–15 strong rounded ribs per whorl, obsolete below suture, strongest on shoulder keel and dying out on the base of body whorl. Each runs obliquely back from shoulder to keel then turns to pass in a gentle curve towards the lip on to the base, where it flexes back slightly

before dying out. Fine growth lines visible on ribs and interspaces. Fasciole polished, with fine growth lines. Columella with a large posterior and two smaller anterior plaits, the two posterior ones continuing on to the neck as low rounded ribs, the third beneath fasciole. Columella and neck flexed somewhat to right. Outer lip incomplete.

Dimensions (holotype): Height, 11; diameter, 5 mm.

Locality: 2314, Takapau (N.E.) S.D. 2661, Tahoraite (S.W.) S.D. Sandstone facies of the Waitotaran.

The shoulder and cord recall Vexillitra Marwick, but the shell is an Austromitra, differing from other species in the shoulder and suppression of spiral sculpture. Named in honour of Captain A. M. Quennell, who was engaged in field work in the Dannevirke Subdivision in 1936–38.

Buccinulidae.

“Aeneator” problematicus n.sp. (Plate 30; Fig. 26.)

Shell small for the genus, with ornature sculpture. Protoconch and uppermost spire whorls missing. Four and a-half whorls present including the body whorl. Whorls strongly convex, shouldered above and contracted to suture below. Periphery mid-way between sutures which are strongly undulating. Body whorl steeply contracting below the periphery. Axial sculpture: 10–12 strong, almost vertical, ribs commencing low at the suture, highest at the periphery, dying out on base and wider than the deeply recessed interspaces between them. Three coarse raised threads below the shoulder, the middle one strongest and forming the periphery, are the dominant spirals; fine intestitial threads are interposed between them on the body whorl. Above these dominant threads, low down on the shoulder, are three finer threads, the subsutural area being otherwise largely free from spiral sculpture. Below the dominant spirals on the body whorl there are 12 spirals becoming wider spaced towards the base where they tend to develop fine interstitial threads, but coarser and more closely spaced on the neck, opposite the point where the denticles are developed on the parietal wall External lip and posterior canal damaged. Internal lip with a parietal smear over the base of the body whorl posteriorly, becoming distinct anteriorly on the column, where there are three obliquely placed denticles.

Dimensions (unique holotype): Height (actual), 17 (estimated) 18.5; diameter, 9 mm.

Locality: 2314, Takapau S.D. (sandy facies of Waitotaran).

The generic location is purely provisional as the protoeonch and apertural features are incomplete. The sculpture is coarser than known species of Aeneator, and the species probably belongs to a new group which would include a further new species from the Westland Pliocene.

Aeneator drewi n.sp. (Plate 29; Figs, 13, 15.)

Shell of moderate size, similar in general shape and sculptural pattern to genotype, but strikingly different in whorl shape and suture. Protoconch of two and a-half whorls, domed and smooth,

Neptuneidae.

Zelandiella aff. pliocenica Powell.

Specimens referable to this, the last species of the genus to appear in the Tertiary, come from G.S. 2731, a basal Opoitian limestone near Paeroa, Mangaotoro N.W. They show no significant differences from Waitotaran examples. The species also occurs below the Waitotaran in the Westland Blue Bottom.

Cominellidae.

Cominula attenuata n.sp. (Plate 30; Fig. 25.)

Hutton's figures (T.N.Z.I., vol. 17, pl. 18, fig. 7 and Macleay Mem. Vol., pl. 7, fig. 35) of hamiltoni and the dimensions given in the description of that species show that he was dealing with the short, squat form of shell so common in the Petane (Upper Nukumaruan) horizons of Hawke's Bay. From Lower Nukumaruan beds in the same district comes this new species distinguished from hamiltoni by its high spire and narrow shell form. C. attenuata is similar to hamiltoni in details of protoconch and ornamentation except that the axial ribs are one or two fewer per whorl, and more closely spaced. The chief and most striking difference is, however, in the tighter coiling of attenuata, which gives it a relatively higher spire and a less expanded body whorl. These features are reflected in dimensions. Specimens from G.S. 2687 contain both types but no extremely squat hamiltoni. The locality is both stratigraphically and faunally intermediate between Upper and Lower Nukumaruan beds. Thus the Upper Nukumaruan Pelicaria convexa has replaced P. acuminata but Chlamys delicatula, which is restricted to Lower Nukumaruan beds, persists This lends support to the idea that Cominula attenuata is the direct ancestor of hamiltoni.

Localities: 2491, 2492, 2417, Tahoraite S.D., 736 (“Petane and Scinde Id.” mixed collection, 1884), 2687, Tahoraite S.D. (mixed population).

The above is a case of a gradational change in a lineage through geological time. It may be contrasted with what appears to be a sudden morphological change in a lineage; at approximately the same horizon in the Nukumaruan, for example, Pelicaria convexa (Marwick) suddenly replaces P. acuminata without any intermediate populations. It is to such sudden changes in the stratigraphical column that the term “mutations of Waagen” was once applied. However, modern

evolutionary doctrine (Huxley, 1942, p. 174) would explain such abrupt changes at one locality as due to the sudden immigration into a district of a form which has had a gradual development in a distant region. Change in climatic or other conditions is likely to favour such sudden appearance in the column, whereas slow gradual alteration in a lineage may occur irrespective of environmental conditions.

Zephos tuturewa n.sp. (Plate 30; Fig. 24.)

Similar to the genotype (cingulata, Hutton) and to onokeana King, differing in its smaller size, and in details of shape, sculpture and parietal callus. Shell depressed and squat, more so than most extreme topotypes of onokeana, whorls convex and not shouldered. Protoconch and earliest spire whorls decorticated. On penultimate whorl 4–5 spiral threads, the upper two wide spaced on the incipient shoulder. Axial ribs more closely spaced than in onokeana; 16–17 per whorl compared with 14–15 in King's species. On body whorl 13 further spirals are developed between suture and fasciole, making 18 in all, sub-equal in strength and not becoming so strong basally as they do in onokeana. Axials dying out just before fasciole. Fasciole strong and well defined. Outer lip missing. Inner lip with thickened parietal callus rising above the suture in the holotype.

Dimensions: Height, 16; diameter, 11.5 mm.

Locality: 2747, Mangaotoro (N.W.) S.D., east of Tuturewa Mountain (Opoitian).

From cingulata, which appears (from the figure) very close to onokeana, the new species differs in its depressed shape, in the prolongation of the axials and the base, and in the heavy parietal callus. Z. purchasi (Suter) (Pal. Bull. 5, Plate 4, fig. 20) has even more axial ribs per whorl (20) and a “faint tubercle below the suture” on the inner lip.

Fasciolariidae.

Falsicolus teuriensis n.sp. (Plate 30; Fig. 20.)

A Falsicolus of the allani-morgani group, differing from these species in the length of the spire, which, measured from a given suture, is considerably less than the greatest width of the whorl above the suture. Suture placed high on whorl, shortly below keel, slightly undulating as it passes over the axials. No conspicuous lower keel of axials as on allani. Shoulder somewhat more concave than in morgani, but axial nodules similar in number (6–8 per whorl) and in shape. Spiral sculpture much finer than in morgani; about 20 fine threads on shoulder above periphery and 4–5 below periphery on spire whorls. Aperture and column missing.

Dimensions (unique damaged holotype—actual): Height, 21.5; diameter, 23.3 mm. Spire from suture (estimated), 16 mm.

Locality: 2371. Te Uri Rd., Mangaotoro (N.E.) S.D., Tutamoe Series.

Muricidae.

Typhis tepunga n.sp. (Plate 30; Fig. 21.)

A Pliocene representative of the New Zealand Miocene species known as T. hebetatus (Hutt.), differing from that species in its more slender build. Shell smaller than adult hebetatus and less acutely angled at periphery. Varices five per whorl, marked by a break in continuity of shell in front of a broad, rounded, and fairly smooth variceal rib. Each varix dies out above shoulder, and on periphery bears an upward-directed short irregular hollow spine; rarely there is a second much weaker spine half way down to the base. Half way between a pair of varices a prominent wide hollow spine projects upward and slightly backward, its base extending on to the shoulder and thus situated higher on the shell than the variceal spine. Shell otherwise smooth except for growth lines; suture markedly waved. Spire equal in height to aperture and canal. Aperture oval, with well defined, moderately thick, and continuous projecting rim. Umbilicus and tubular perforation small.

Dimensions: Height, 22; width, 13.5 mm.

Localities: 2661 (type), 2499 (Tahoraite S.D.). 2314 (Takapau S.D.) Calcareous sandstone faces of Waitotaran.

This species is named in honour of Mr. Martin Te Punga, who did field work in Dannevirke Subdivision in 1940–41.

Zeatrophon murrayae n.sp. (Plate 31; Fig. 30.)

Of the Z. bonneti (Cossmann) line but smaller and differing in sculpture and apex. Nucleus minute, rounded and symmetrically placed. First two post nuclear whorls smooth and bulbous, third developing a smooth carina just below the middle and another shortly appearing above it. Protoconch as a whole less depressed and domelike than in bonneti. Spire whorls similar to those of bonneti. Two chief spiral cords, one at the shoulder angle, the other half way between angle and suture below, while a third strong cord is almost hidden by the suture. Axials, about 24 per whorl, as compared with 16–20 in bonneti, much weaker than spirals, and usually obsolete on the shoulder, which is smoother than in Cossmann's species. Small nodules developed at intersection of axials and spirals bear short spines in fresh specimens. On body whorl, axials become obsolete on neck. Base below sutural cord bears seven or eight fairly close-spaced threads, not conspicuously fenestrated by the axials. Aperture much as in bonneti, but wider and not usually denticulate. Canal as in bonneti.

Dimensions (holotype): Height, 18; diameter, 10 mm.

Localities: 3093 (type) Hunterville-Turakina Valley Road (Upper Nukumaruan) and several Nukumaruan localities in Dannevirke Subdivision.

Named after Miss K. S. Murray, N.Z. Geological Survey, whose illustrations for this paper speak for themselves.

Zeatrophon elegans n.sp. (Plate 31; Fig. 32.)

A handsome species with no obvious affinities. Shell moderate sized. Protoconch of unique specimen lacks initial whorls but has been polygyrate and symmetrical. Post embryonic whorls, five.

Spire whorls turreted with a wide, slightly concave shoulder and two coarse nodulous spiral cords forming periphery sloping inwards slightly to suture below cord. Axials 12 per whorl, broad, low and rounded, continued over the shoulder which is otherwise smooth in spire whorls although, on body whorl, two to three narrow grooves develop, defining low threads between them. The two peripheral spiral cords of spire whorls are equal in strength and form nodules, elongated horizontally, where intersected by axials. On penultimate whorl a fine intermediary spiral thread, similarly intersected by axials, develops between the chief cords, and there is a further fine thread above suture. The same sculpture is continued on to body whorl where, on base, below last mentioned fine thread, there are six wide, flatly rounded cords, the upper three separated by finer interstitial threads. Fasciole fairly strong, sculptured by growth lines. Aperture ovoid, slightly angled at the upper of the two peripheral cords, constricted anteriorly to form a moderately long slightly twisted anterior siphonal canal. Outer lip raised into eight strong denticles.

Dimensions: Height, 18 5; diameter, 9.5 mm.

Locality: 2687, Kumeroa (Uppermost Lower Nukumaruan).

The shell is reminiscent of the form of the polymorphic Z. ambiguus, in which the spirals have developed with suppression of the axial varices.

Cancellariidae.

Zeadmete kumeroa n.sp. (Plate 31; Fig. 34.)

Shell large for the genus, agreeing with trailli rather than with other Pliocene species in the weakness of the subsutural shoulder. Protoconch normal. Spiral whorls convex, not straight-sided, with four strong spiral threads, two weak threads on shoulder and a weaker one above suture, crossed by weaker axials, producing nodulous intersections and squarish pitlike interspaces. On penulimate and body whorls, axial sculpture becomes obsolete, and secondary threads develop between the spirals, of which there are 23 on the body whorl, crossed by growth lines. Outer lip thin sinused at the weak shoulder and running forward in a broad sweep before retreating to anterior canal. Inner lip apparently without parietal callus and with two weak subequal plaits on columella.

Dimensions: Height, 11.7, diameter 6 mm.

Locality: 2687 (Tahoraite S.W.), Uppermost Lower Nukumaruan.

The other Nukumaruan species, teres Laws, differs in the strong shoulder and entire absence of radials. Z. aupouria Powell is close, and as it is based on a juvenile shell, comparison is difficult. However, in aupouria the shoulder is more defined and the first post-embryonic whorl bears seven spirals, whereas in the present species there are only three or four initial threads.

Bonellitia aff. lacunosa (Hutton).

Specimens from Waitotaran and Lower Nukumaruan horizons differ from topotypes (Petane, Upper Nukumaruan) in the strength of the axials which dominate the spiral threads, and in the large

number of interstitials in the interspaces between the chief spirals. In the strength of their axials they resemble the Opoitian (?) fundata Marwick, but differ from that species, too, in the large number of interstitials.

Pyrenidae.

Zemitrella subsuturalis n.sp. (Plate 31; Fig. 28.)

Shell moderate sized for the genus. Spire outline straight, interrupted somewhat by the slightly incised suture. Protoconch smooth, shining and papilliform, nucleus depressed, embryonic lip thickened where it passes abruptly into post-embryonic shell. Sculpture, an ill-defined subsutural groove, and many (about 13) fine spiral grooves separating threads on the base and neck. Whorls otherwise smooth except for faint growth lines. Outer lip thickened within, having a prominent denticle a third the distance from posterior notch.

Dimensions of unique holotype: Height, 7·5; diameter, 3 mm.

Locality: 2312, Ongaonga Road. Petane Series.

Apparently akin to Z. haroldi Laws, which has fewer anterior threads, and to Z. pseudomarginata among Recent species; neither of these species has a sub-sutural groove.

Antizafra obtusa n.sp. (Plate 31; Fig. 31.)

Shell similar to A. speighti but with the whorls more convex so that they have a much less straight outline. Sculpture strong. Protoconch as in other species of genus, i.e., nucleus sunk in smooth dome-like first post-nuclear whorl, and a second shining whorl with an abrupt change to adult ornament. However, probably owing to an accident to the embryo, the embryonic lip is not simple as in all other species, but has a distinct posterior sinus. Whorls gently convex. Sculpture: 15–16 broadly rounded axial ribs per whorl, dying out on base, crossed by seven well defined spiral ridges on spire whorls. Spirals strongest on periphery, and equally developed on summits of axials and in interspaces between them. Ten similar spirals on base, followed posteriorly by four or more finer, more closely spaced threads on neck. Outer lip and tip of column broken.

Dimensions of holotype (unique), slightly damaged: Height, 8; diameter, 4 mm.

Locality: Ongaonga Rd. (Petane Series).

The abnormal protoconch lip is probably accidental. The convexity of the whorls distinguishes this species from others of the genus.

Antizafra obsoleta n.sp. (Plate 31; Fig. 29.)

Shell of same size and shape as speighti (Marwick) but with ornament considerably reduced, axials almost obsolete, giving a strong resemblance to Zemitrella sulcata (Hutton). Spiral sculpture: One strong sub-sutural groove and five spaced below on spire whorls, tending to become obsolete where crossed by axials. Below these, on body whorl, 12 similarly spaced but deeper grooves, becoming weaker on canal. Axial sculpture: About 20 broadly rounded axial riblets per whorl (about as broad as their interspaces), strongest between subsutural groove and suture, but obsolete on base. Spirals largely restricted to interspaces between axials except for sub-sutural and