The Tertiary (Waitematan) Molluscan Fauna of Oneroa, Waiheke Island.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 60, 1930, Page 395

The Tertiary (Waitematan) Molluscan Fauna of Oneroa, Waiheke Island. By A. W. B. Powell and J. A. Bartrum. [Read before the Auckland Institute, 28th May, 1929; received by Editor, 24th June, 1929; issued separately, 30th November, 1929. Plates 34–50. Introduction. About the middle of 1927 Mr. E. W. Tetley, a student of the Geology Department of Auckland University College, brought to one of the authors (Bartrum) news of the existence of fossiliferous Tertiary beds near Oneroa on the north-west coast of Waiheke Island. On investigation, his discovery proved to be one of the most important in the history of the geology of the surroundings of Auckland, for it has previously proved almost impossible to obtain from the Waitemata beds any variety of fossils, apart from those of Polyzoa and Foraminifera, sufficiently well preserved for accurate determination, whilst the Waiheke beds contain a highly varied molluscan fauna. Bartrum is also further indebted to Mr. Tetley and his family for hospitality extended to him on several of his collecting trips to the island. Fortunately he was soon able to enlist the services of Mr. A. W. B. Powell, both in collecting and describing the material, and the paper here published is the result. The fossiliferous beds at Oneroa are best exposed in a small bay half a mile north-west of Oneroa Beach. There they consist of argillaceous sandstones overlying well-developed conglomerates, in which greywacke pebbles and fragments of poorly-consolidated argillaceous sandstone predominate, these latter apparently worn from adjacent lithologically similar sediments of Tertiary age. They are gently tilted approximately to the south, and rest upon the Trias-Jura greywacke which is the predominant rock of Waiheke Island. They appear again, though practically unfossiliferous, in a pocket-beach nearer to Oneroa Beach, and again at the west end of this latter beach, where they constitute the shore-platform buried beneath modern beach-sands and only rarely exposed to view. They are again fossiliferous at this last locality, but the shells there are, so badly leached that their collection is exceedingly difficult. The general mode of occurrence of the Tertiary beds suggests that these latter accumulated in small sheltered pocket-like hollows worn in the greywacke terrain prior to Tertiary submergence. As the shells are obtained from the wave-cut platform and seacliffs of the bay west of Oneroa Beach, it is necessary to select suitable times and tides for collecting. Relatively ready access to

the locality is provided by launches and by steamers of the Northern Steamship Company, which make return excursion trips from Auckland on Sundays, as well as one-way trips on other days of the week. The material is very fragile and considerable time and patience are necessary in collecting, working out of the matrix and preserving the shells, but the time and labour are well repaid, because the shells prove to have quite unusual interest. The present note describes collections made by the authors during visits, each usually only a few hours in duration, spread out over the past year. After a few of these visits the addition of fresh species to the faunal lists became difficult, and although the lists here published are regarded as preliminary, it is felt that considerable time and labour will need to be expended before they can be appreciably expanded. As the succeeding pages will show, many of the species described are representatives of groups not previously recorded from New Zealand, which appear subsequently to have become extinct; other species appear clearly to be ancestral to modern New Zealand forms. The proportion of new species present is indeed surprising. The authors are greatly indebted to Professor R. Speight for the loan of types, and to Dr. J. Marwick for the loan of types and for much helpful information. The accurate correlation of the Waiheke beds with the standard fossiliferous horizons of other parts of New Zealand is very difficult on account of the large percentage of new species. The fauna is decidedly littoral or shallow-water in character, as is shown by the genera Haliotis, Cellana, Bembicium, Lepsiella, Pyrazus, Ischnochiton, Bankia and Musculus which are present. The only other large collection of littoral forms from the New Zealand Tertiary so far recorded is that recently described by Dr. J. Marwick (Trans. N.Z. Inst., vol. 59, 1929, pp. 903–934) from Chatton, Southland. Dr. Marwick has also had difficulty in correlation on account of the great number of new forms contained in these Chatton beds, but after a thorough investigation has assigned them to the Oligocene period. The greater portion of the Waihcke species belong to genera of which ancestral series are poorly represented in the New Zealand Tertiary, so that they have little or no value for purposes of correlation. Fourteen out of the total of 78 species collected have closely related forms in the Awamoan (Lower Miocene), 7 are definitely Hutchinsonian (Upper Oligocene) in character, whilst 6 have very close relatives at Chatton, and in the beds at Waikaia which are probably Ototaran and certainly older than Awamoan. The assemblage of species therefore indicates that the Oneroa beds represent a stage higher than that of the Chatton strata, but certainly lower than Awamoan, so that they can reasonably be assumed to be the equivalent of the Hutchinsonian stage of the Upper Oligocene.

Out of the 78 species listed 5 have been referred to Recent species and constitute a higher percentage of Recent forms than now generally accepted for the Oligocene. These Recent records, however, are based on such poor and solitary specimens that the finding of better material may readily delete many if not all of them. The elements in the Waiheke fauna are well shown by the following lists in which related species are compared. A. Ototaran? Pyrazus consobrinus n. sp. Waiheke. P. sutherlandi Marwick, Chatton. Zefallacia benesulcata n. sp. Waiheke. Z. chattonensis Marwick, Chatton. Acteon oneroaensis n. sp. Waiheke. A. chattonensis Marwick, Chatton. Xymenella asperula n. sp. Waiheke. X. inambitiosa Marwick, Chatton. Struthiolaria lawsei n. sp. Waiheke. S. prior Finlay, Waikaia. Austrosipho (V.) exoptatus n. sp. Waiheke. A. (V.) n. sp. Clifden. B. Hutchinsonian. Austrofusus (Neocola) oneroaensis n. sp. Waiheke. A. (N.) apudalpha Finlay, Otiake. Diplomitra waitemataensis n. sp. Waiheke. D. masefieldi (Marshall), Pakaurangi Point. Cominella (Paracominia) lignaria, n. sp. Waiheke. Cominella (Paracominia) finalyi, n. sp. Waiheke. C. (P.) n. sp. Pakaurangi Point. Navicula waitemataensis n. sp. Waiheke. N. pittensis (Marwick), Chatham Islands. Austrotoma excavata (Suter), Waiheke. A. excavata (Suter), Pakaurangi Point. Macoma robini Finlay, Waiheke. M. robini Finlay, Otiake. C. Awamoan. Charonia (Charoniella) arthritica n. sp. Waiheke. C. (C.) neozelanica (M. & M.), Target Gully. Cylichnina enucleata n. sp. Waiheke. C. soror (Suter), Target Gully. ‘Guraleus’ sepelibilis n. sp. Waiheke. G. gracilenta (Suter), White Rock River. Buccinulum (Evarnula) tetleyi n. sp. Waiheke. B. (E.) crassatinum Powell, Ardgowan. Tugali navicula Finlay, Waiheke. T. navicula Finlay, Target Gully.

Pyrgulina cf. pseudorugata M. & M., Waiheke. P. pseudorugata M. & M., Target Gully. Dosinia (Raina) bensoni Marwick, Waiheke. D. (R.) bensoni Marwick, Target Gully. Turritella (Zeacolpus) tetleyi n. sp. Waiheke. T. (Z.) abscisa Suter, Target Gully. Turritella (Maoricolpus) gittosina n. sp. Waiheke. Turritella (Maoricolpus) waitemataensis n. sp. Waiheke. T. cavershamensis Harris, Caversham. Phenatoma (Cryptomella) transenna (Suter), Waiheke. P. (C.) transenna (Suter), Awamoa. Nozeba candida Finlay, Waiheke. N. candida Finlay, Pukeuri. Melatoma cf. awamoaensis (Hutton), Waiheke. M. awamoaensis (Hutton), Awamoa. D. Ototaran to Awamoan. Corbula pumila Hutton, Waiheke. C. pumila Hutton, White Rock River. Description Of Species. Class: Pelecypoda. Genus Anomia Linné, 1758. Anomia trigonopsis Hutton, 1877. Finlay (Trans. N.Z. Inst., vol. 57, 1926, pp. 446–447) suggests: that the two species A. trigonopsis Hutton and A. walteri Hector are the same. It appears, however, in Recent specimens examined as if the internal byssal and muscle scars of walteri are more equal in their size than those of trigonopsis. A number of the Waiheke fossil specimens have very constant characters of these scars, which invariably show considerable disparity of size. A few of the shells show strong radial sculpture. Genus Navicula Blainville, 1825. Type: N. noae (Linné sub Arca): monotype. It now appears that the genus name Arca has long been used in the wrong sense, for Dr. Marwick has brought to the attention of the authors the following nomenclatural note which is quoted from a paper by L. R. Cox on “Neogene and Quaternary Mollusca from the Zanzibar Protectorate,” 1927, p. 93:—“The above species (Arca: noae Linné) is usually taken as the genotype of Arca s. str.; unfortunately (as Mr. J. R. le B. Tomlin has pointed out to me), the Linnean species A. tortuosa was definitely designated as genotype of Arca by J. G. Children so early as 1823 (Quart. Journ. Sci. Lit. and Arts, 14, p. 319); hence the necessity for reviving Blainville's: name (Dict. Sci. Nat., 34, p. 319).”

In addition to the new species described below, Arca subvelata Suter, 1917, A. cottoni Waghorn, 1926, and A. pittensis Marwick, 1928, also belong to this genus. Navicula waitemataensis n. sp. (Figs. 23, 24). Sub-quadrate elevated shell with strong close-spaced radial ribs which are slightly beaded by growth-lines. Cardinal area of moderate size, concave; ligament-grooves are imperfectly shown on holotype, though 6 major chevrons are visible on a paratype. Beaks sharp and incurved, moderately approximate, directed slightly forward. A strong narrowly-rounded fold-like shoulder runs from beak to lower posterior angle, the dorsal slope below this flattened and steepening towards the beak. In one fragmentary paratype this shoulder is acutely angled, so that lower angle of the posterior margin is correspondingly sharpened—almost beaked. In another there is, on the contrary, a broadening of the fold, with resulting widening of this angle and reduction in ventral gape and in steepness of posterior dorsal slope. Posterior margin obtusely angled at straight hinge-line, and then acutely angled below at the posterior fold. Anterior margin descends vertically in a sharp angle from hinge-line, and then forms narrowly-rounded angle with sinuous ventral margin. The latter is broadly excavated for a prominent sub-medium gape, and rises obliquely, gently convex, to form the acute posterior angle. Hinge slightly imperfect; about 33 oblique teeth. Ornamentation on steep dorsal slope above posterior shoulder differs from that of rest of valve in having the ribs less regular in size and spacing, more widely separated and less regularly beaded by growth-lines. There are about 42 radial ribs from shoulder to anterior end of shell; a few beaded intermediate ribs appear between the major ones on the holotype. Dimensions of holotype (right valve; in A.U.C. collection): Length, 31 mm.; height, 14.5 mm.; thickness, 11 mm. This shell approaches closely Navicula pittensis (Marwick) from Flower-pot Harbour, Pitt I., Chatham Is., from which it differs in having more numerous hinge-teeth and less than half the number of ligamental chevrons found in that species. Genus Mytilus Linné, 1758. Mytilus tetleyi n. sp. (Figs. 46, 47, 103). A very large strongly-arched sub-triangular shell with relatively thick shell-material. Beaks terminal, very sharply angled; from them a somewhat abruptly-raised hump-like fold runs near and sub-parallel to ventral margin, gradually merging posteriorly into general tumescence of valve on its dorsal side, but maintaining an abrupt ventral slope. Dorsal margin of valve long; imperfect in holotype; on paratype it is at first gently convex and then becomes almost straight

before coming to the broad but definite angle at posterior margin. In holotype the cast suggests that the dorsal margin rises in a distinct hump a little in front of the middle; behind the hump it is straight. The posterior margin descends steeply, broadly convex, making a somewhat narrowly rounded angle at the ventral margin. This latter is broadly sinuous, gently convex on anterior half and shallowly concave on posterior half. There is a very steep ascent to longitudinal fold of valve from ventral margin, almost vertical on posterior half, but more gradual anteriorly. Internally (paratypes) the area of the inset ligament is particularly broad, straight and slightly concave; it is sculptured by oblique transverse arcuate growth-lines, and bordered below by a sharp low ridge with a deep narrow parallel groove between it and hinge-plate, whilst a similar but shallower groove lies between the depression of the ligament area and the dorsal margin. Hinge-plate rather heavy, thickened and broadly-rounded, but teeth indistinct. Valve-interior nacreous as usual. External sculpture of the usual concentric growth-lines, but very dense faint radial striations are just visible on marginal portions of epidermis. Brown epidermal colour preserved. Dimensions of holotype (in collection of A. W. B. Powell): Height, 182 mm.; length, 84 mm.; thickness (one valve), 34 mm. Figured paratype (in A.U.C. collection): length—actual, 115 mm.; estimated, 135 mm.; height, 62 mm. This shell is closely similar to M. canaliculus Martyn, but differs in its proportionately longer hinge-line, much broader ligament area, and much more acute and stronger longitudinal hump of valves. It has been named after Mr. E. W. Tetley, of Auckland University College, who first drew the attention of the authors to the fossiliferous nature of the Oneroa beds. Genus Musculus Bolten, 1798. Musculus cf. impactus (Hermann). See Iredale (Trans. N.Z. Inst., vol. 47, 1915, p. 485, and Proc-Linn. Soc. N.S.W., vol. 49, 1924, p. 196) and Dall (Proc. U.S. Nat. Mus., vol. 63, art. 10, pp. 1–4). One well-preserved specimen now in the A.U.C. collection and several impressions observed in the matrix agree well with impactus. Genus Isognomon Solander, 1786. Isognomon oneroaensis n. sp. (Figs. 69. 106). In 1917, Suter (N.Z. Geol. Surv. Pal. Bull., No. 5, 1917, p. 68) described and figured fragments of the hinge and almost the whole valve of a species of the genus under the name Melina zealandica

Suter. Later Marshall and Murdoch (Trans. N.Z. Inst., vol. 52, 1920, p. 136; vol. 53, 1921, p. 77) added further figures and information of this species from almost perfect material which they had collected near Waverley. A very large specimen of Isognomon was found at Oneroa Beach, but unfortunately was almost destroyed during haphazard excavations in search of fossils before it was unearthed. It differs very decidedly in the hinge from I. zealandicum (Suter), for the transverse resilium furrows are more numerous and closer together. It has, however, the same relatively massive lamellar character as the other species. Later the right valve of a small specimen showing almost complete outline, but with the hinge much damaged and eroded, was collected and has been selected as holotype and described below. The shell is moderately quadrate in outline and moderately convex. Beak at about anterior third. Anterior ear small, slightly concave and inflexed below; outline is then broadly rounded towards ventral margin. Parts of the ventral and posterior margins are damaged, so that the true outline is uncertain, but enough remains to show that the posterior margin descends rather straight and curves towards the broadly-rounded ventral margin. A broad rounded internal rib descends almost vertically from the umbonal cavity almost meeting the anterior margin at about half its height and dividing the ear from the rest of the shell. The true position of the muscle scar is obscured by adventitious irregularities. The hinge details are provided by the paratype mentioned above, which is very massive and represents only about a quarter of the full length of the hinge. The fragment shows 6 closely-spaced vertical long and narrow grooves, so that the complete hinge apparently had about 24 resilium furrows. In contrast the entire hinge of zealandicum has only 4 or 5 resilifers. Dimensions of holotype (in collection of A. W. B. Powell): Height, 94 mm.; length, 75 mm.; approximate thickness about 15 mm. Paratype (fragmentary; in A.U.C. collection): maximum length, 85.5 mm.; width of hinge-plate, 38.2 mm. Genus Ostrea Linné, 1758. Subgenus Gigantostrea Sacco, 1897. Ostrea (Gigantostrea) gittosina n. sp. (Figs. 64, 65). This new species is closely allied to O. wuellerstorfi Zittel, which has recently been included in the group Gigantostrea Sacco, 1897, by Finlay (Trans. N.Z. Inst., vol. 59, 1928, p. 266). It has been named in honour of Mrs. A. W. B. Powell (née Gíttos) who has given most valuable assistance in collecting from the Oneroa beds. Large externally gibbous shell, with irregular closely-spaced radial costae-like folds and somewhat imbricating concentric lamellae.

Left valve sub-circular, but somewhat sinuous in outline, contracted towards beaks; strongly convex; shell material extremely thick at centre (approximately 30 mm.), but gradually thinning, until margin is thin and sharp, except at hinge. Beak small and irregular. Hinge-plate heavy; short, but broad, with parallel striations which cross the sub-triangular or spoon-shaped deeply concave resilium pit. Lower (internal) margin of hinge-plate sharply defined and making a sharp sub-rectangular edge interrupted by a concave sinus at resilium pit. Anterior and posterior margins of valve slope fairly steeply from hinge-plate, and are more or less erenate internally, especially the long slightly concave posterior dorsal margin. Muscular impression sub-circular, sub-central and deeply inset at its upper margin. Right valve (paratype) sub-circular, highly irregularly flattened, with irregular concentric ornamentation. Radial folds not visible. Hinge area similar to that of other valve; marginal crenulation distinct. Muscle scar not deeply inset. Dimensions of holotype (left valve): Length, 123 mm.; height, 136 mm.; thickness, 80 mm. approximately. Paratype (right valve): Height, 130 mm.; length, 118 mm.; maximum thickness of material, approximately 30 mm. Holotype and figured paratype in collection of A. W. B. Powell. Compared with wuellerstorfi the present species differs in the characters of the hinge-plate, in the rapid descent of the anterior and posterior margins from the hinge and in a curious flexing of the valves. This last feature is quite constant in all specimens so far collected. It appears as a deep cleft in the left valve and as a corresponding hump or ridge on the right valve. A specimen in the collection of A. W. B. Powell, collected by Mr. Flinn, of Auckland, from near Manganese Point, Whangarei Harbour, shows the same flexing of the valves. Suter (N.Z. Geol. Surv. Pal. Bull., No. 3, 1915, p. 53, pl. 7, fig. 3) figures a shell from Kawau as a plesiotype of wuellerstorfi which, judged by the figure, is identical with the new species. The type of wuellerstorfi was collected from beds of the West Coast north of Raglan by the “Novara” Expedition, but their horizon in the Oamaruian sequence is doubtful. Genus Eucrassatella Iredale, 1924. Eucrassatella attenuata (Hutton). (Fig. 107). 1873. Cat. Tert. Moll., p. 24. 1914. N.Z. Geol. Surv. Pal. Bull., No. 2, p. 48, pl. 12, fig. 1. Holotype from Broken River (Awamoan). A well-preserved right valve and several incomplete specimens from Waiheke agree very well with Buchanan's drawing of the

holotype (loc. cit., 1914) in having the same concave upper posterior margin. Two Target Gully specimens in A. W. B. Powell's collection differ in having this upper posterior margin convex and in possessing a less massive hinge. If these characters are constant the Target Gully shell represents a new species. Several specimens ascribed to E. ampla by the authors, recently collected at Kawau by Powell, are much less trigonal in outline than Zittel's figure shows. The upper posterior margin, however, is convex and quite unlike that of Hutton's attenuata. The authors are publishing figures of a Waiheke specimen, as the origin of Buchanan's drawing of the hinge of this species is doubtful, for the holotype is still filled with matrix. Dimensions of figured shell (in collection of A. W. B. Powell): Length, 115 mm.; height, 83 mm.; thickness (one valve), 24 mm. Genus Notomyrtea Iredale, 1924. Finlay (Trans. N.Z. Inst., vol. 57, 1926, p. 461) has lately examined New Zealand species recently referred to the genus Lucinida and considers that they have closest resemblances to Iredale's genus Notomyrtea, though many require sub-generic separation under a new sub-genus Pteromyrtea. A species of the group occurs at Waiheke, but the material so far collected does not permit of its exact determination. Genus Melliteryx Iredale, 1924. It has been pointed out by Finlay in his Commentary on New Zealand Molluscan Systematics (Trans. N.Z. Inst., vol. 57, 1926, p. 463) that the generic name Melliteryx Iredale (Proc. Linn. Soc. N.S.W., vol. 49, 1924, p. 207) should replace Erycina for the Recent New Zealand shell formerly known as Erycina parva (Deshayes). A close relative of parva has appeared in the Waiheke beds and is described below as a new species. Melliteryx mirificus n. sp. (Fig. 41). This species has larger adult size than the Recent species parva, whilst it is also less convex, and relatively thinner in material. In addition, the several Oneroa specimens ascribed to the new species do not appear to be so varied as those of the Recent species. Very small sub-elliptical somewhat compressed convex shell, with median relatively large beaks, regularly rounded ends and fairly steeply descending broadly convex dorsal margins. Ventral margin flattened in the middle and merging at front and back into somewhat narrowly arcuate lateral margins. Ornamentation appears under high magnification as a microscopic pseudo-punctate pattern, with inconspicuous regular concentric striae due to growth-stages. The punctuation is due to the minute dissection of growth-lines by oblique microscopic threads or

riblets which are sinuous and apparently spirally coiled with regard to the beak, though this could not clearly be seen. Hinge is not visible in the holotype, but an imperfect paratype shows the distal portion of the hinge with typical elongated laterals. Dimensions of holotype (in collection of A. W. B. Powell): Length, 6.5 mm.; height, 5 mm. Genus Macoma Leach, 1819. Macoma hesterna n. sp. (Fig. 76). Thin compressed ovate shell with small sharp little-raised beaks at about middle of dorsal surface. Posterior end is attenuated through more rapid descent there of broadly convex ventral margin; sharply angled about the middle. Anterior half of shell slightly the longer; broadly-rounded at anterior margin. Dorsal margins descend regularly and slowly almost straight from beak, bending gradually near posterior margin to form sharp angle with ascending ventral margin, whilst the anterior dorsal margin descends to unite in a regular curve with the anterior margin. A very faint broad fold runs from beak to posterior angle. Right valve almost flat; left valve lightly convex. Surface smooth with faint close-spaced concentric growth-lines. Dimensions of holotype (right valve; in A.U.C. collection): Length, 19 mm.; height, 10.5 mm.; thickness indeterminate. Paratype (left valve; in collection of A. W. B. Powell): Length, 21 mm.; height, 12 mm. The species differs from huttoni and huttoni sterrha Suter mainly in the position of the beak and in the higher position of the posterior angle, whilst the ventral margin is more convex. Macoma robini Finlay (Trans. N.Z. Inst., vol. 55, 1924, p. 474). The type of this shell is from Otiake (Hutchinsonian). Several specimens ascribed to this species were collected at Waiheke, the largest (Fig. 54) measuring 29.5 mm. in length by 18.5 mm. in height. “Macoma” oneroaensis n. sp. (Fig. 62). Relatively compressed concentrically ornamented shell, broadly-rounded in front and produced into a rostrum behind. Beaks little swollen; a little anterior of middle of dorsal surface. Anterior dorsal margin descends slowly, almost straight, to convex anterior border, there forming a distinct rounded angle. Posterior dorsal margin also nearly straight and similarly descending slowly to a sharp narrowly-angled beak at posterior margin. Ventral margin is sinuous behind and then trends towards anterior margin as a sweeping curve slightly flattened at middle. Sculpture of fairly sharply-raised regularly-spaced concentric threads, locally elevated into low sharp sub-erect lamellae, separated by intervening finer threads.

Dimensions of holotype (in collection of A. W. B. Powell; incomplete): Length, 41 mm.; height, 29.5 mm.; estimated complete length, 43 mm. Dimensions of paratype (internal cast); Length, 47 mm.; height, 29.5 mm.; thickness of one valve, 7.5 mm. The species differs from Raeta tenuiplicata in the higher position of the rostrum and the consequent slower descent of the posterior dorsal margin. This interesting shell, which is provisionally referred to Macoma, is undoubtedly congeneric with Raeta tenuiplicata Bartrum (Trans. N.Z. Inst., vol. 51, 1919, p. 97), but both shells differ from typical Macoma in having the posterior end sharply attenuated, but not folded or flexed. The hinge of a species close to tenuiplicata from Waitomo Valley which was kindly forwarded by Dr. Marwick is, however, very near that of Macoma. Dr. Marwick will later deal with the exact generic position of these shells. Genus Leptomya A. Adams, 1864. Type: L. cochlearis Hinds. Leptomya waitemataensis n. sp. (Fig. 109). Shell moderately large, sub-circular, very little inflated, thin and fragile; smooth except for numerous well-defined growth-lines. Beak prominent, central, inclined inwards. Anterior end descending gradually almost straight from beak, becoming regularly and broadly rounded towards middle and blending below with the broadly rounded ventral margin. Posterior end narrowly rounded and slightly rostrate at middle. Posterior dorsal slope steeper than the anterior; slightly concave above and straight towards rostrum, which is narrowly-rounded and slightly excavated before joining the ventral curve. Hinge as in the Recent retiaria (Hutton) (= lintea Hutton). Dimensions of holotype (in collection of A. W. B. Powell): Height, 15 mm.; length, 19 mm.; thickness (one valve), 3.5 mm. Paratype (in A.U.C. collection): 18.5 mm. × 26 mm. × 4.5 mm. (one-valve). The Waiheke species differs from retiaria in having a more circular outline, whilst its posterior dorsal slope is concave to straight and not slightly convex as in the Recent species; in addition it lacks radial sculpture. Leptomya simplex Marwick (Trans. N.Z. Inst., vol. 56, 1926, p. 331) has both radial and concentric sculpture, whilst L. concentrica Marwick (Ibid., vol. 58, 1928, p. 468) differs in having a more prominent broader and lower rostrum. Genus Scalpomactra Finlay, 1926. Type: Mactra scalpellum Reeve. Scalpomactra biconvexa n. sp. (Fig. 108). Shell small, thin, smooth, elongate-oval in outline and moderately convex. Beak small, produced; situated slightly in front of the

middle. Right valve with anterior end produced and narrowly rounded. Anterior dorsal slope gradual and almost straight. Ventral margin broadly and evenly convex. Posterior end slightly longer than anterior one and more narrowly rounded. Posterior dorsal slope more rapidly descending than anterior, and broadly but distinctly convex. Surface smooth except for fine microscopic growth-striae. Margins of valve thin and sharp. Hinge as in scalpellum. Dimensions of holotype (in collection of A. W. B. Powell): Height, 5.75 mm.; length, 11 mm.; thickness (one valve), 1.25 mm. The Waiheke species differs from scalpellum in being elongateoval and not triangular in outline. Genus Lutraria Lamarck, 1799. Lutraria trapezoidalis n. sp. (Figs. 89, 90). Ovate-trapezoid shell; valves moderately convex; beaks at anterior third, broad, flattened, sharply pointed. Sculpture of fine close growth-lines somewhat unevenly developed. Dorsal margins elevated into a narrow sharp ridge; straight and very slowly descending. Lateral margins rounded, with no distinct angles. Ventral margin straight; slightly crushed in holotype. Holotype is a small incomplete shell, but imperfect crushed large paratypes are available. Dimensions of holotype (incomplete): Length, 38 mm.; height, 18 mm. Proportions indicated by growth-lines are: 29 mm. × 13 mm. Paratype (Fig. 89): 105 mm. × 51 mm. Both holotype and figured paratype in A.U.C. collection. The new species is similar to solida, but easily separable from it by its long almost straight and sub-parallel dorsal and ventral margins. Genus Dosinia Scopoli, 1777. Subgenus Raina Marwick, 1927. Dosinia (Raina) bensoni Marwick. (Trans. N.Z. Inst., vol. 57, 1927, p. 587). A common species of Dosinia at Oneroa is a shell very closely similar to the Awamoan species bensoni Marwick; it differs, however, in being constantly more massive and in having slightly wider hinge-plate and greater inflation. Even in young shells the edges of the valves are quite thick. The divergence of the Oneroa shell from the Awamoan one (Target Gully) can be expected in view of the fact that the Waiheke beds are slightly older than Awamoan. Dr. Marwick has assured the authors that bensoni shows a moderate range of variation, so that they consider that their Oneroa shell is best included provisionally in this species. Its differences from bensoni

appear to demand, however, the description which is appended below and illustrated by Figs. 70–73. Shell massive, large, sub-circular with extremely thick shell-material. Moderately ventricose; beaks fairly large, at about anterior third. Lunule deeply inset, elongate-cordate; generally large or very large, but variable in size. A strongly-developed elongate much-depressed escutcheon present. Hinge-plate extremely heavy; teeth considerably raised. Right valve (Figs. 71, 72) with short, narrow but strong anterior cardinal, a strong sub-vertical somewhat rugose middle cardinal rising about its middle length into a blunt tooth-like process, a very broad strongly bifid posterior cardinal posteriorly grooved and furnished above with a long sinuous ridge, and finally a narrow but distinct long posterior lateral sub-parallel to the adjacent cardinal. Posteriorly there is a broad, very shallow lateral pit, longitudinally and finely grooved, the edge of the nymph forming a sharply raised lamella. Anteriorly the lateral pit is prominent with two deep grooves parallel to the valve margin at the lunule, one originating from above and the other from below the anterior cardinal. Hinge of left valve (Fig. 73) less well-preserved. Anterior cardinal narrow, strongly elevated; etched, but possibly grooved; sloping forward. Posterior cardinal long, arched, strong, rugose; bifid as result of a broad longitudinal groove. The anterior lateral is a strong triangular knob near the lower margin of the hingeplate. Posterior lateral pit generally shallow, but deeper and transversely and irregularly furrowed above, with a sharp raised ridge-between it and nymph. Pallial sinus relatively small, narrow, sharply angular, directed to top of anterior adductor impression; does not extend to half diameter of shell. Surface decorticated in all specimens collected. Original sculpture probably similar to that of typical bensoni, consisting of narrow concentric grooves separating broad flat polished interspaces up to 2 mm. in width, but decortication has developed the reverse effect, namely low concentric lamellae with broad flat interspaces. Dimensions of specimen of Figs. 70 and 71 (right valve; in A.U.C. collection): Height, 64.6 mm.; length, 65.4 mm.; thickness (one valve), 19.4 mm. Another specimen has height, 60 mm.; length; 62.8 mm.; double thickness, 37.5 mm. Genus Tawera Marwick, 1927. Tawera cf. bartrumi Marwick. Several specimens were collected of a shell very close to T. bartrumi Marwick, but differing in finer sculpture, shells of approximately the same size as the type of bartrumi having 8 ribs per millimetre in place of 5 or 6. It is doubtful, however, if this difference is constant enough to justify the separation of the Waiheke shell as a new species.

Genus Cardium Linné, 1758. Subgenus Trachycardium Mörch, 1853. This subgenus is represented in the Waiheke beds by a noble species over 5 in. in length. It is considered conspecific with Hutton's Cardium greyi, 1873, from the basal Waitemata beds at Kawau. The holotype of greyi is very poorly preserved and should not have been described, for it is an incomplete crushed cast of a juvenile shell in which the outlines are irregular and the shell-material is limited to about 2 sq. ins. in area. Buchanan's figure represents a restoration (N.Z. Geol. Surv. Pal. Bull., No. 3, pl. 1, fig. 3) and is a hazardous piece of guess work. As the Waiheke and Kawau beds have several species in common and both beds are near the visible base of the Waitemata Series, there can be no reasonable doubt that the Cardium in both beds is the same. A specimen (Figs. 35, 36) from Oneroa in the A.U.C. collection is accordingly selected as a plesiotype on account of its exposed and well-preserved hinge, though the shell is slightly crushed at the beak and the ribs are fewer and slightly more distant than in other specimens. The true proportions are best taken from another specimen recently collected in perfect condition. It also appears that Cardiuon huttoni Ihering from the lower gorge of Waipara River is identical with greyi; the outline of the figured topotype (N.Z. Geol. Surv. Pal. Bull., No. 3, pl. 6, fig. 5) is also incomplete, but the number and character of the ribs and the convexity of the shell fit the Waiheke species very well. A large Cardium from Locality 847, East Wairarapa, in the Geological Survey collection also seems to be conspecific. Cardium (Trachycardium) greyi Hutton. 1873. Cardium greyi Hutton, Cat. Tert. Moll., p. 28. 1887. Cardium greyi Hutton, Proc. Linn. Soc. N.S.W. (2), vol. 1, p. 227. 1915. Cardium greyi Hutton. Suter, N.Z. Geol. Surv. Pal. Bull., 3, p. 59, pl. 1, fig. 3. 1887. Cardium multiradiatum Sowerby. Hutton, loc. cit., vol. 1, p. 1, p. 227. Not of Sowerby. 1907. Cardium huttoni Ihering. Anal. Mus. Nac. Buenos Aires, vol. 14, p. 291. 1915. Cardium huttoni Ihering. Suter, N.Z. Geol. Surv. Pal. Bull., No. 3, p. 58, pl. 6, fig. 5. Neither of the two Waiheke specimens here figured present the true outlines of the normal shell. In the plesiotype (Figs. 35, 36) the beak and dorsal margin are slightly crushed, while in the other the whole shell is slightly distorted giving a more oblique outline. The dimensions of a normal right valve are: Length, 118 mm.; height, 114 mm.; thickness 42 mm. The figured right valve (Figs. 35, 36) has the anterior end convex and the posterior one flattened; shell-material thick. Beaks

large, sub-median, well-inflated, strongly incurved and directed forwords. Anterior dorsal margin broadly convex, descending somewhat slowly to form a highly obtuse rounded angle with the anterior margin. The latter is a regular strongly arcuate curve continuous with the ventral margin. Posterior dorsal margin (see Fig. 36) straight and sub-horizontal; forms an angle of 120° with the flattened posterior margin; the latter very gently convex, almost flat, at a small angle with the vertical. Anterior margin joins ventral margin in a regularly rounded curve. Sculpture: 51 raised rounded strong ribs (55–60 in other specimens) with interspaces a little narrower than the ribs; the latter may be narrow at the crest, sometimes possessing a distinct keel. The posterior slope is separated by a broader flat-bottomed furrow running from the beak to the lower posterior angle; this and adjacent posterior furrows are often faintly striate longitudinally. The whole shell is crossed by dense concentric growth-lines developed on lower part as faint thin low lamellae generally oblique upwards, but sub-erect near ventral margin. Hinge (right valve): hinge-plate relatively not heavy, but teeth strong. Below beak a strongly elevated smooth tusk-like sharply conical median cardinal, with a faint short oblique anterior cardinal separated from the dorsal margin by a shallow groove. Immediately behind beak there is a broad and deep quadrate pad, followed beneath the straight wide nymph by a strong thick oblique much-elevated posterior lateral, with a broad hollow between it and nymph. Anterior lateral not elevated above dorsal margin, but very heavy and thick, rising gradually to a cusp at its posterior end and separated from the dorsal margin by a groove-like hollow. Anterior dorsal margin of valve thin; elsewhere the margin is thick. Where visible ventrally it is strongly crenate at the incidence of the radial ribs. Dimensions of plesiotype (right valve: in A.U.C. collection): Length, 118 mm.; height, 113 mm.; thickness, approximately 40 mm. The figured left valve (Figs. 39, 40) has the beak very broad, well inflated, strongly incurved and bent forwards; it is slightly in advance of the median position. General ventricose nature of the shell less pronounced posteriorly, where the valve is flatter then anteriorly. Anterior dorsal margin slightly imperfect; rises sharply immediately against beak, then descends slowly gently convex to unite in a somewhat narrowly rounded curve with the gently convex anterior margin, forming an indefinite rounded angle. Basal margin strongly convex, joining the lateral margins in regular curves conforming with the obliquity of the shell. Posterior dorsal margin longer than anterior; descends broadly convex with moderate obliquity to the broadly convex posterior margin. Sculpture: along posterior dorsal slope, sub-parallel to margin, there is a narrow sharply elevated but low fold which delimits a narrow marginal slightly excavated part of the dorsal surface which

has been depressed in connection with the formation of the hinge. Whole of surface ornamented by about 60 strong rounded radial ribs, the intervening furrows much narrower than the ribs on the posterior half, but widening gradually until of equal width anteriorly. On posterior slope these interspaces are flattened and show occasional traces of radial striae. On posterior half of valve many of the ribs have several (usually 2 or 3) thin low longitudinal lamella-like threads along their crests which appear to surmount the general concentric ornamentation of close growth-lines which are developed upon the ribs of the lower part of the shell as low lamellae usually directed obliquely upwards, but more erect near ventral margin. Hinge-plate not heavy; a little imperfect on account of fractures. Nymph appears to be a narrow elongated groove. There are 2 cardinal teeth, an oblique short boss-like one almost touching the beak, and immediately below it a second very stout conical highly-elevated tusk-like tooth with a large deep socket between it and the other cardinal and another oblique one above. Posterior cardinal encrusted by algal growth in figured specimen (Fig. 40). Near the base of the tusk-like cardinal the hinge-plate descends abruptly near the margin and then rises gradually as a smooth rounded slope to culminate anteriorly in a narrow cusp-like anterior lateral with a shallow conical pit etched beneath at its base. Behind the beak the hinge-plate is first very broadly flattened and then narrows and furnishes posteriorly a faint sub-obsolete lateral with a shallow elongate groove beneath it. Internal margin strongly crenate at the incidence of the radial ribs. Dimensions of figured left valve (in collection of A. W. B. Powell): Length, 130 mm.; height, 128 mm.; approximate thickness, 44 mm. This species is quite common at Oneroa, but specimens are-extremely difficult to collect intact because they have been severely shattered by movements of the argillaceous sandstone in which they are embedded. Genus Corbula Bruguière, 1797. Corbula pumila Hutton. Common in the Oneroa beds. Corbula aff. zelandica Q. & G. There are a few comparatively smooth, poorly preserved valves related to the Recent zelandica Q. & G. Genus Bankia Gray, 1842. Bankia turneri n. sp. (Figs. 74, 75). This fossil species differs from the Recent B. australis Calman— = Teredo saulii (Wright) of Suter's Manual, pp. 1021–1022; see Iredale, Proc. Linn. Soc. N.S.W., vol. 49, pt. 3, 1924, p. 214—in the form of the shell and in details of sculpture.

The shell is sub-globose, the valves highly convex, with very broad, strongly incurved beaks and very wide posterior auricles. The body of the shell is divided into two sub-equal portions by a shallow groove passing from near the beaks to the mid-ventral margin. The two valves collected (left and right) are both imperfect at the beaks, but show that the dorsal margin descends at first convex, and then enters a narrow sinus before passing to a sharp beak-like angle at the anterior margin very little below the level of the beaks. The ventral margin is somewhat imperfect. Comparison with species closely related in form and ornamentation indicates, however, that a re-entrant angle on the ventral margin is expectable, with its two bounding lines respectively parallel to the sets of minute ribs ornamenting the two sculptural divisions of the anterior half of the body. On this assumption the ventral margin passes from the beak at the anterior margin at only a moderate angle with the horizontal, and then, at two-thirds the distance from the median groove, forms a re-entrant angle of about 110°. The ventral margin is flattened beneath the median groove and soon becomes very narrowly and regularly arcuate, forming an angle at the lower posterior margin. The posterior dorsal margin is broadly convex, descending to the angle at the lower posterior margin in a fairly regular curve separating the body from the auricle. The auricle is sub-quadrate in outline and large; its surface is unevenly flattened, meeting the body in a distinct but shallow sulcus, and roundly up-flexed towards its posterior margin. Its dorsal margin is concave near the body and then forms a rounded angle of 90° at its posterior margin, from which it descends at first vertically and straight and then strongly oblique and convex to join the body a little above the angle on its lower posterior margin, yielding a re-entrant angle of about 130°. Beak and hinge area imperfect, though the former is seen to be continued internally as a large sub-globular callosity, in front of which there is the narrow sinus at the dorsal margin. The margins of this sinus are thickened with callus which is limited in spread on the holotype (left valve), but in the paratype (right valve; Fig. 75) forms an extensive grooved pad on the dorsal hump of the body adjacent to the sinus, very limited against the anterior marginal beak, but broadening considerably on the other side of the sinus, and with distinct arcuate margin against the sculpture of the body. (See Fig. 75). Ornamentation: On the auricle and the posterior half of the body there are dense growth-lines forming an obtuse angle at the shallow sulcus between the auricle and the body. On the auricle of the paratype they have a tendency to be raised as rounded sub-imbricating lamellae. The dorsi-ventral groove is bounded by a very definite sharp but low edge posteriorly, and anteriorly by a very narrow sharp-crested fold, distinct over the hump of the body but flattening out and becoming almost obsolete ventrally. At the crest of this fold there is the junction of the concentric growth lines of the groove and the subvertical ribs of the adjacent section of the anterior half of the body.

It is bordered the whole of its length by a strong rib which rises from the groove and is distinctly beaded by notches resulting from regular rest-stages of the growth-lines, whilst the ventral portion of the fold is crossed at regular intervals by raised riblets developed from the growth-lines, which are deflected down highly obliquely to the axial rib of the groove. Transverse to this latter there are growth lines which are generally very faint, but, on the holotype, seem to be a little stronger at regular intervals. In the holotype also there are traces of a very faint discontinuous axial rib bordering the major rib on its posterior side. The anterior half of the body is divided into two sculptural sections by a line passing from the beak, at an angle of about 15° with the dorsi-ventral groove, to the re-entrant angle at the ventral margin. On the anterior section strongly-raised minute densely-crowded rounded ribs (about 7 per mm. at their posterior limit) radiate out from the beak at the anterior margin, only slightly oblique to the horizontal. They are microscopically granulose on unworn portions. On the lancet-shaped section nearer the median groove there are similar but denser and finer rounded riblets (about 14 per mm.) with narrow groove-like interspaces. They are in parallel series faintly oblique (at about 7°) to the margin of the groove and are microscopically beaded by close-spaced transverse grooves. The internal characters of the shells are not visible. One of the authors (A.W.B.P.) was so fortunate as to collect even a portion of a well-preserved pallet exposing the flat inner side and six of the pectinate appendages. These are attached to the central stalk at an angle of about 35°, which is a much smaller angle than in the case of the common Recent Bankia australis Calman (= Teredo saulii Wright). The handle is about 4 mm. long and gradually tapers down from lower pair of appendages to a cylindrical rod; its greatest width is 2.5 mm. Dimensions of holotype (left valve): Length, 12.6 mm.; height, 9 mm.; approximate thickness, 5.3 mm. Paratype (right valve): Length (incomplete), 11.7 mm.; height, 10.5 mm. Both holotype and figured paratype are in the collection of A. W. B. Powell. Class: Gasteropoda. Genus Tugali Gray, 1843. Tugali navicula Finlay. The type is from the Awamoan Target Gully “shell bed” of Oamaru. In the collection of A. W. B. Powell there is a well-preserved specimen of the species from Oneroa with the following dimensions: Length, 14.5 mm.; height, 3.5 mm.; width, 8 mm. Genus Turbo Linnaeus, 1758. Two species of this group were found in the Oneroa material, one referable to Modelia, Gray, 1840, and the other probably near to the South African genus Sarmaticus Gray, 1847.

Modelia aff. granosa (Martyn) (Fig. 63). Finlay (Trans. N.Z. Inst., vol. 57, 1926, pp. 366–367) has advised the use of the generic name Modelia for granosa, an action that seems quite justified, judging by the distinctive operculum. The single specimen collected (in collection of A. W. B. Powell) is much erushed; it has the outline of M. granosa, but differs in sculpture, especially as shown by the penultimate whorl, for it consists of flattened broad spiral ribs alternating with narrow granular ones with linear interspaces. On the penultimate whorl there are 5 broad and 4 narrow ribs. Outline of whorls regularly convex. Where other characters are preserved they resemble those of granosa, in which all the spiral ribs are granular. Dimensions of specimen (imperfect and crushed): Height, 31.3 mm.; maximum diameter, 26.7 mm. It has been considered inadvisable to institute a new species on the material at present available. Sarmaticus cf. superbus (Zittel). Several fragmentary specimens of a large Turbo which shows close resemblance in its coarse tubercles to Sarmaticus Gray were collected along with a single relatively complete shell now in the A.U.C. collection. The species appears to be the same as that described as superbus by Zittel (Reise der Novara, Geol., vol. 2, pt. 1, p. 39, 1865) from the basal Waitemata beds at Cape Rodney. The operculum of Sarmaticus is tubercular, so that, if that figured in Fig. 42 belongs to the Oneroa species now discussed, superbus is not a typical member of the genus. Genus Cellana H. Adams, 1869. Cellana thomsoni n. sp. (Fig. 12). Depressed sub-conical radiately ribbed shell oval in outline, with sharp apex about one-sixth length from anterior margin. Apex sharp, directed obliquely forwards. Prominent radial ornamentation of low rounded ribs of unequal strength, which are crossed by strong concentric faintly imbricating growth-lines (about 18 per mm.). The radial ribs are carved into flattened nodules owing to close-spaced periodic rest-stages of growthlines represented by deep, narrow, rounded grooves. Interspaces between stronger radials are often occupied by from 1 to 3 fainter radials with shallowly-rounded interspaces. Distinction between primary and secondary ribs is difficult, but there appear to be about 18 major radials on each half of shell. Margin faintly undulating at incidence of major ribs, whilst internally these latter cause poorly-defined shallow grooves. Interior nacreous; muscular impression indistinct. Shell-material thin. Dimensions of holotype: Length, 14 mm.; breadth, 10 mm.; height, 2.1 mm.

The holotype is the only specimen collected, and is in the A.U.C. collection. It has been named after the late Dr. J. Allan Thomson, as a small tribute to his work on polymorphism in the common limpet Cellana radians (Gmelin) (J. A. Thomson, N.Z. Journ. Sci. & Tech., vol. 2, 1919, pp. 264–267). Genus Bembicium Philippi, 1846 (Zeitschr. Malak., 1846, p. 129). This genus is typically Southern Australian and Tasmanian in distribution. In his Alphabetical List of N.Z. Tertiary Mollusca, 1918, p. 7., Suter lists Bembicium melanostomum (Gmelin). Previously in his: Manual of N.Z. Mollusca, 1913, pp. 167–168, he included Risella melanostoma Gmelin recorded by Hutton in his Manual of N.Z. Mollusca, 1880, p. 79, as a synonym of Astraca sulcata davisii (Stowe). Finlay, however (Trans. N.Z. Inst., vol. 57, 1926, p. 368) adopts the prior sub-specific name kielmanseyi Zelebor, 1866, for this latter shell, referring it to Cookia Lesson, 1832, which he gives full generic rank. The authors have no knowledge of the Tertiary shell which Suter referred to Bembicium melanostomum (Gmelin), but a species from Oneroa, described below, is undoubtedly distinct from Cookia sulcata kielmanseyi (Zelebor) and the Recent Australian melanostoma. Bembicium priscum n. sp. (Figs. 7, 8). Small axially costate and spirally ornamented conical shell with sharp spire and flattish base. Whorls 4, with small conical protoconch of about 2 extra smooth whorls. Spire outline almost straight, but post-nuclear spire-whorls have a distinct re-entrant angle about one-quarter height above suture, yielding a sub-concave outline. Outline of body-whorl deflected down slightly from line of spire; faintly concave; contracts very rapidly below lower peripheral angle towards shortened base. Spiral sculpture of post-nuclear whorls consists of prominent narrow raised cords (7 on penultimate whorl) with sub-equal interspaces, the lowest (at the suture) much the strongest and continuing to form a sharp peripheral angle to shell. Axial sculpture of 13 strong blunt ribs radiating continuously from the apex to the periphery, which they render strongly serrate. Base shortened, with 4 somewhat unequal inclined lamellaté cords, the outermost of which is larger than the others and forms a decided flange. It is situated about one-third the radial distance in from the periphery and is continuous with the outer lip. Aperture entire, sub-circular in basal aspect, but obliquely oval in elevation; peristome discontinuous. Outer lip thin, regularly convex, but rapidly retracting as it swings highly obliquely to the left to join the basal margin of aperture in a regular curve. Inner lip with thin narrow glaze. Columella short, polished, straight above, arcuate below, forming a curve continuous with that of basal lip. Dimensions of holotype (in A.U.C. collection): Height, 4.25 mm.; diameter, 4 mm.

Genus Estea Iredale, 1915. Estea verticostata n. sp. (Figs. 25, 26). A minute elongate-conical, turretted, axially-ribbed shell allied to E. impressa (Hutton). Whorls 5, including 2 of protoconch; whorl-outline very faintly convex, almost flat; suture impressed. Body-whorl convex, contracting very rapidly at base; it has a distinct depression encircling the base parallel to the suture and commencing about the middle of the parietal wall. Ornamentation of rounded low strong ribs passing down from suture to suture very slightly oblique to the right; about 30 per whorl, with sub-equal interspaces. Dimensions of holotype (in A.U.C. collection): Height, 2 mm.; diameter, 1 mm. The new species differs from impressa (Hutton), its nearest relative, in having more numerous axial costae, in the presence of a basal depression and in the absence of submargining at the suture. Genus Subonoba Iredale, 1915. Type: Rissoa fumata Suter. Subonoba aff. fumata (Suter). The single specimen collected is so worn that accurate specific determination is impossible. Its shape is similar to that of fumata, but it appears to have more numerous spiral threads (about 12) on the penultimate whorl than this latter species which has 10. Genus Nozeba Iredale, 1915. Type: Rissoa emarginata Hutton. Nozeba candida Finlay (Trans. N.Z. Inst., vol. 55, 1924, p. 490). Fairly plentiful, well-preserved, but rather fragile. The type is from Pukeuri, but the species is also found at Ardgowan and Target Gully, Oamaru. Genus Zefallacia Finlay, 1926. Type: Fastigiella australis Suter (Awamoan = Lower Miocene). The species described below is represented by better material than in the case of the genotype, so that it is possible to give a more detailed description of the generic features. The Waiheke species differs from Z. australis (Suter) in that it is considerably larger and has a more strongly channelled suture with consequent wider sutural shoulder. It differs from a Chatton species Z. chattonensis Marwick recently described by Marwick (Trans. N.Z. Inst., vol. 59, 1929, p. 917) in being proportionately narrower and in having its spire-whorls higher and more deeply channelled. An interesting feature of this genus now revealed by better material is the fine nodulous keel of the early spire-whorls.

Zefallacia benesulcata n. sp. (Figs. 27–31). Shell elongate, turretted, with spiral and faint axial ornamentation on earlier whorls; body-whorl small. Spire elongate-conical with outline almost straight above, but-inclined to be gradate below as result of strongly channelled suture. Outline of spire-whorls sharply angled at upper suture, then descending straight and vertically into lower channelled suture. Body-whorl-has sharp lower angle; it then contracts rapidly at base. Its lower angle has a low keel provided with 2 close-spaced rounded spiral ribs-separated by a sub-equal groove. Apex and earlier whorls of holotype missing; 16 whorls visible. Protoconch imperfect on all specimens collected. Sculpture tends to become obsolete in later whorls. First 10 have prominent narrow keel at angle just below suture, crossed somewhat obliquely from left to right by close-spaced rib-like nodules. Below this there are from 2 to 4 (2 on holotype) variably-spaced moderately wide nodular einguli, separated by rather narrow grooves; they decrease until they disappear about the tenth whorl of holotype (about the seventeenth of a paratype with reasonably complete spire), though the nodules on these einguli have become obsolete a little earlier. The major keel continues strong to about the same whorl, but then somewhat abruptly loses its conspicuous riblets and rapidly fades away. On the lower whorls the only traces of spiral sculpture are irregularly and widely-spaced striations or faint threads on some of the paratypes (Figs. 27, 28) and low rounded ribs on the base. The holotype has only a few of these basal spiral ribs, but a paratype (Fig. 27) has no less than 14 equidistant strong threads between the lower keel of the body-whorl and the smooth fasciole, whilst at its outer lip above these there are other slightly divergent similar threads. The whole shell is crowded with conspicuous growth-lines concave to the left, which become deeply impressed as they pass downwards over the whorls to the lower bounding sutures. On the upper whorls they are developed as faint oblique close-spaced irregular riblets, which, in the uppermost whorls, especially in the holotype, form elongated nodules on the sub-sutural keel. Suture very deeply channelled; near the posterior canal ascends abruptly over half the height of the preceding whorl in holotype, though not so far in paratypes. Aperture oblique, pyriform, with strong wide posterior notch and a moderately short, narrow and somewhat enclosed anterior canal (paratype) strongly flexed to left and decidedly retracted (Figs. 27, 28, 31). Outer lip rather thin, dilated; descends lightly convex at first and then sweeps strongly around, a little sinuous, to form basal margin. Inner lip with callus light on parietal wall, but extremely heavily laminated near the posterior canal and on the base at the columella, coming to a sharp point on the pillar; its outer margin at the base is most abrupt, and in some paratypes there is beneath it a distinct chink. Columella short, almost straight above, strongly bent to left below. Dimensions in holotype (incomplete): Height, 66.5 mm.; diameter, 21.25 mm. Figured paratypes (incomplete): 55.5 mm × 20.8 mm.; 61 mm. × 20.6 mm.

Holotype in collection of A. W. B. Powell; figured paratyes in A.U.C. collection. The shell described has striking resemblances to Terebra in spire, but its base lacks the fasciole of this latter genus, and its aperture is distinctly cerithioid. Genus Pyrazus Montfort, 1810 (Conch. Syst., vol. 2, p. 458). Type: Pyrazus baudini Montfort (= Clava herculea Martyn = Cerithium ebeninum Bruguière. See Hedley, Proc. Linn. Soc. N.S.W., 1906, pp. 529–531). The genotype is a common New South Wales shell, strictly estuarine in habitat, crawling among roots of mangroves and generally distributed over mud-flats. The genus extends apparently from Tasmania as far north as Southern Queensland, where it is replaced in the tropics by the closely-allied and widely-distributed genus Terebralia. P. consobrinus, one of the new species described below, is very closely allied to a third New Zealand species from Chatton, Southland, recently described by Dr. J. Marwick (Trans. N.Z. Inst., vol. 59, 1929, p. 917). The Chatton shell may be distinguished by its proportionately larger spire, more numerous axial costae (13 on penultimate whorl as compared with 10 in consobrinus) and by these costae diminishing in strength towards the upper suture in the Chatton species P. sutherlandi Marwick and towards the lower suture in consobrinus. The second Waiheke species (waitemataensis) is not closely related to the other two New Zealand species, for it has a much shorter spire, a larger body-whorl and very weakly-developed axial costae. The genus is a noteworthy addition to the New Zealand Tertiary fauna, for the largest cerithioid species now living in the seas of the area are only about an inch in height. Pyrazus consobrinus n. sp. (Figs. 32, 33). Elongated axially costate shell; height of spire 2¼ times that of aperture; about 12 whorls; apex present, but worn. Outline of spire fairly straight, whorls lightly convex. Suture lightly impressed, slightly sinuous on account of axial costae. Body-whorl descends lightly convex, almost straight, until it inbends very rapidly towards pillar at base. Columella nearly straight; parietal wall very slightly convex. Aperture strongly oblique; though somewhat imperfect, appears thoroughly typical of the genus except that canal is a little longer than usual. Inner lip with thick callus which is sharply delineated from body-whorl and thickens above to a pad near notch, and below to form a thick sharply raised plate on the pillar. Outer lip imperfect, but obviously expanded; thin; strongly angled as it turns towards the base. Axial sculpture of broad low straight vertical regular axial costae, diminishing towards lower suture and with interspaces about

equal to the costae. Closely spaced in upper whorls, but wider apart below and somewhat less strong; 10 on penultimate whorl. Absent on ventral surface of body whorl (above aperture), but to left of this free space (well shown by Fig. 32) there is a strong irregularly tumescent pseudo-varix. Spiral sculpture of flattish very slightly raised cords; 11 on penultimate whorl; especially strong where they cross the pseudo-varix; sub-equidistant and with interspaces probably equal to cords, though etched on holotype. On a paratype with perfectly-preserved sculpture (Fig. 33) the interspaces between cords vary and may be sub-linear; they are occupied by brown colour-bands quite brilliant when first removed from the matrix. Dimensions of holotype (fairly complete): Height, 86.5 mm.; maximum breadth, 35 mm. Paratype (incomplete): Height, 87 mm.; diameter, 29 mm. Holotype and paratype in collection of A. W. B. Powell. Pyrazus waitemataensis n. sp. (Fig. 34). Like the previous species this is a large turretted axially costate shell, but with conical spire somewhat short for this genus—a little over 1½ times the height of the aperture. Spire with almost straight outlines, whorls being only faintly convex, little impressed at suture; 7 post-nuclear whorls; apex worn. Paratypes show that suture ascends fairly steeply behind to site of posterior canal; faintly undulating at axial costae. Body-whorl descends sub-vertically, very slightly convex, until it contracts below towards pillar; in holotype the descent is more oblique than in para-types. Aperture incomplete below; oval; strongly oblique to left; broad deep sinus above; anterior canal broken away. Outer lip expanded, with broad shallow but distinct sinus immediately below upper canal; not thickened; produced forwards. Inner lip spread fairly broadly over parietal wall with heavy callus pad at posterior canal. Callus also forms a thick plate over columella, with (in paratypes) a slight cleft between it and base, and ending (in a paratype) as a sharp point on the pillar. Columella apparently straight; parietal wall faintly concave. Axial sculpture of broad low wide-spaced costae (about 8 per whorl), strong in upper spire-whorls (in paratypes) but decreasing until practically obsolete on body-whorl. Spiral sculpture over whole shell of fairly regularly-spaced deep linear grooves; about 19 on penultimate whorl. Dimensions of holotype (a little flattened): Height, 73 mm.; maximum breadth, 33 mm. Holotype in collection of A. W. B. Powell. One fairly complete paratype shows a considerably blunter spire than holotype, but a considerable number of less complete specimens indicate that the more elongated forms are of the normal type.

Genus Turritella Lamarck, 1799. Subgenus Maoricolpus Finlay, 1926. Turritella (Maoricolpus) gittosina n. sp. (Fig. 20). Large, very gently tapering spirally lirate shell with about 16 whorls in the imperfect holotype, from which the apex and a few early whorls are missing. Spire angle 16°. Outline of upper whorls flattened, but middle and lower whorls have a low broad spiral fold just below the suture. Below this the outline is moderately strongly concave. Suture impressed on lower whorls. Body-whorl contracts very rapidly at base with a narrowly rounded angle keeled by stronger spiral ornamentation beneath its median concavity. On penultimate whorl there are 11 strong sub-equidistant regular spiral threads, with occasional faint traces of fine intermediate spirals. In upper whorls the second spiral thread below the suture is stronger than the others, and makes a faint keel on the sub-sutural fold, as is the case also on the lower angle of body-whorl. On the base there are 6 strong regularly-spaced spirals, with a few faint intermediate threads. Aperture incomplete. Inner lip has very widely-spread thick callus over parietal wall, base and columella. Columella straight above, incomplete below. Dimensions of holotype (incomplete): Height, 127 mm.; diameter, 30.5 mm. Holotype, the only specimen, in collection of A. W. B. Powell. This shell is closely allied to T. (M.) cavershamensis. Compared with specimens from Mount Harris which are assumed to be typical of this species, the Waiheke shell differs in having more regularly developed, fewer and more widely- and evenly-spaced spiral cords. Its sub-sutural fold occupies the same position as in cavershamensis. Turritella (Maoricolpus) waitemataensis n. sp. (Fig. 19). Long moderately large tapering turretted shell with 11 whorls present; base, apex and several early whorls missing. Whorls are approximately flat in general outline, but have a distinct broad spiral sulcus or concavity between broad low rounded folds near upper and lower sutures on all but the earlier whorls. The lower fold is slightly stronger than the upper one. Body-whorl angled below and then contracting relatively slowly at the base. Ornamentation of spiral threads stronger on earlier whorls and fainter on later ones; some of them are more strongly developed than others, especially on earlier whorls. At first there are 2 upper and a lower of these strong threads, which are distinctly elevated and gradually develop into the sutural folds already mentioned. The upper fold is devoid of strong spirals, but the lower one has 2 or 3 of them on later whorls. The lower whorls are traversed by from 24 to 26 spirals per whorl.

Suture abutting, prominently so in lowest whorls. Base (paratype) sculptured with 7 or 8 irregularly-developed spiral cords. In addition to the spiral ornamentation there are dense, very distinct sinuous growth-lines which indicate that the sinus at the outer lip is deep; in many paratypes close-spaced narrow brownish colour-bands corresponding with the growth-lines are present. Aperture (paratype) sub-circular, but outer lip is imperfect. Inner lip (imperfect) with narrow thin callus; excavated at the parietal wall. Columella gently concave to the right, merging in the basal margin of aperture. Dimensions of holotype (imperfect): Height, 78 mm.; diameter; 21 mm. Holotype in collection of A. W. B. Powell. The species is the commonest of those of the genus present at Oneroa. It is related to both cavershamensis and gittosina and ancestral to the Recent rosea. It differs from these species in its development of spiral folds, for it has a strong fold at the upper suture and a slightly stronger one below at the lower suture. It is readily distinguished from gittosina by the greater number of its spiral threads. Subgenus Zeacolpus Finlay, 1926. Turritella (Zeacolpus) tetleyi, n. sp. (Figs. 21, 22). This species is based on incomplete specimens, but is characterised by very distinctive ornamentation. The shell has the usual gently tapering turretted form (spire angle 13°) with straight spire outline interrupted by steep narrow spiral ridges developed as ornamentation. About 11 whorls in holotype; base and earlier whorls missing. Suture abutting. Ornamentation consists of close-spaced fairly strong spiral threads (about 22 per whorl) and two elevated, prominent, steep spiral ridges sigmoid in cross-profile, but with rounded crests. One of these is immediately below the suture, and the other just below the middle. The latter is much the stronger in earlier whorls, but later the two become sub-equal, and at the same time more rounded and less elevated, as shown by an incomplete paratype (Fig. 22) with maximum and minimum diameters of 7 mm. and 4 mm. respectively. In the lower whorls of paratype the minor spirals become a little irregular in strength and arcuate growth-lines appear, suggesting that the labial sinus is comparatively broad and shallow. Dimensions of holotype (incomplete): Height, 20.5 mm.; diameter, 5.5 mm. Holotype and figured paratype in A.U.C. collection. This shell is related to T. abscisa Suter from Oamaru. The exact locality of the holotype of this latter is not known, but the species is recorded from Target Gully by Finlay (Trans. N.Z. Inst., vol. 55, 1924, p. 502). The Waiheke species is distinct from abscisa, however, for the relative position and character of the spiral ridges are different. In tetleyi the upper one is near the upper suture and the

lower one just below the middle, whilst in abscisa the lower spiral is close to the lower suture and the upper one just above the middle of the whorl. Genus Struthiolaria Lamarck, 1812. Struthiolaria lawsei n. sp. (Figs. 9–11). This new species is of the typical papulosa group near S. prior Finlay (Trans. N.Z. Inst., vol. 56, 1926, p. 228), and is a particularly large form, for specimens have been noted over 5 ins. in length. The collection of good material proved very difficult, however, and the holotype is incomplete. Shell sub-turbinate, large, with very large body-whorl and strongly gradate spire slightly higher than aperture; ornamented by very fine threads and very prominent elongated tubereles at the sharp angle of the whorls. Seven post-nuclear whorls; 2½ in apex. Spire-whorls strongly angled and carinate at middle with nodules on the keel; almost flat above and below keel. Body-whorl strongly bi-angled, with secondary tubercular carina (poorly shown by holotype) on lower angle; below the angle it contracts rapidly at the base. On younger paratypes the lower keel is strongly raised and is fairly prominently and closely tubercular, the nodules twice as numerous as on upper carina, though becoming obsolete towards aperture. Protoconch has 2½ flatly-coiled vertically-depressed whorls; these are followed by a convex whorl with 8 sharply-raised equidistant spiral threads; the next whorl is angled at the middle and has a keel crossed somewhat obliquely by minute close-spaced axial costae which resolve on the succeeding whorls into nodules. These continue to increase in prominence and finally become the prominent strongly-produced, vertically-compressed sharp carinated tubercles already noted; about 7 per whorl in lower whorls, but more numerous in upper whorls. In mature forms growth-stages appear to end with abnormal elongation of one of the spines into a spear-like excrescence from the outer lip (see Fig. 10). This seems to be co-ordinated with the partial or complete suppression of one or two preceding tubercles. Threads of spiral sculpture equidistant, very close and fine (about 3 per mm. on body-whorl) and covering whole of shell. On holotype and one or two large paratypes there is a strong spiral thread a little below lower keel, but this does not appear to be a constant character. Growth-lines faint. Aperture with callus of inner lip spread widely and very heavily on parietal wall and columella, the callus with sharply raised thick border, especially on base and near posterior notch, so that there is often a distinct and even prominent chink beneath it just below the lower angle of body-whorl. Callus not so high as in papulosa, for it does not extend beyond suture near posterior canal. Aperture notched in the usual fashion, the posterior notch very broad. Outer lip polished, generally strongly produced at both angles of body-whorl, especially at the upper, where it may be developed as

the prominent spear-like process already described, with deep sinuses above and below it. Outer lip also very greatly thickened and little reflected, so that its external surface is broadly flattened. Dimensions of holotype: Height, 91.3 mm.; breadth (incomplete), 49.8 mm. Paratype: Height, 59.3 mm.; breadth (including labial spine), 42.1 mm. Holotype and figured paratype in collection of A. W. B. Powell. The species is named in honour of Mr. C. R. Laws, M.Sc., a fellow collector and worker upon New Zealand Tertiary molluses. Genus Zegalerus Finlay, 1926. See H. J. Finlay, Trans. N.Z. Inst., vol. 57, 1926, p. 392. Zegalerus peramplus n. sp. (Fig. 45). Sub-circular convex shell with sub-central low conical spire. Early portion of spire fairly sharply conical. Nucleus about 1 ½ whorls, small, fairly sharply elevated, tilted, almost central. Lower portion of spire more flattened than apex; outlines of whorls gently convex, with impressed suture. Sculpture of distinct growth-lines running obliquely to suture, yielding impression of spiral arrangement. Dimensions of holotype (collection of A. W. B. Powell): Maximum diameter, 44.5 mm.; minimum diameter, 38 mm.; height, approximately 14 mm. The new species is closer to the Recent Z. tenuis (Gray) than to the fossil species Z. crater Finlay (Trans. N.Z. Inst., vol. 57, 1926, p. 392). It has much larger adult size than tenuis and has a less elevated shell. It differs from crater in the greater convexity of its whorls and the resulting more deeply impressed suture. Genus Sigapatella Lesson, 1830. See E. A. Smith, British Antarctic (“Terra Nova”) Expedition, 1910, Zoology, vol. 2, No. 4, Mollusca, Part 1, 1915, p. 82. Sigapatella patulosa n. sp. (Fig. 43). This new species is near S. novae-zelandiae (Lesson), but is distinguished by its proportionately larger body-whorl and by having its nucleus nearer to the margin. Shell large, elliptical, convex, fairly thin; whorls strongly convex; nucleus broken; about 2 ½ adult whorls. Spire not elevated, fairly small, moderately oblique to left and forwards; suture impressed. Surface eroded; sculpture only of distinct growth-lines. Septum not visible. Nucleus at about one-eighth from margin. Dimensions of holotype (in collection of A. W. B. Powell): Length, 40.8 mm.; breadth, 44.2 mm.; height, 17.5 mm. Slightly larger, though imperfect, paratypes have been collected.

Sigapatella subvaricosa n. sp. (Fig. 44). Ovate poorly-elevated shell with sub-marginal apex and rapidly increasing whorls. Apex of holotype lower than succeeding whorls. Body-whorl proportionally large. Shell of about 2 ½ whorls including protoconch. This latter (paratype) of 1 ½ smooth whorls, sharply raised and increasing rapidly in size. Very characteristic sculpture of extremely dense sinuous radial threads, especially prominent in juvenile paratypes. In mature holotype and some fragmentary paratypes this radial sculpture is superimposed upon more or less radially-disposed discontinuous broad low corrugations which occasionally are somewhat imbricated by growth-stages. Shell-material of holotype thin, but in one more strongly arched etched specimen which is presumed to belong to this species, though the radial corrugations are not indicated, it is relatively thick. Basal plate not exposed. Dimensions of holotype: Length, 29 mm.; breadth, 24.5 mm. height, approximately 6.5 mm. Holotype in A.U.C. collection. This species stands nearest to Sigapatella maccoyi Suter from Awamoa. Genus Crepidula. Lamarck, 1799. Subgenus Maoricrypta Finlay, 1926. In a recent paper the present writers (Trans. N.Z. Inst., vol. 59, 1928, p. 144) accepted Humphreys' names of the Museum Calonnianum, 1797, as advocated by both Iredale (Proc. Linn. Soc. N.S.W., vol. 49, 1924, pt. 3, p. 267) and Finlay (Trans. N.Z. Inst., vol. 57, 1926, p. 393), and failed to observe Opinion 51 of the International Commission on Zoological Nomenclature. Dr. Marwick, however, has drawn attention to the matter in the case of the genera Uber and Polinices (Trans. N.Z. Inst., vol. 59, 1929, p. 918). In a private communication to the present writers Dr. Finlay draws attention to a misrepresentation of facts with regard to his genus Maoricrypta in their paper of 1928 (loc. cit., p. 144, which reads as follows “Finlay, … … apparently on the basis of anticipated differences in the radulae of New Zealand shells from those of crepidulids of other areas, creates a new genus Maoricrypta.” Mention was omitted, however, of Finlay's statement that typical Crepidula differed in having a notched septum. The main reason for not accepting Finlay's genus was the fact that the outline of the septum proved variable in specimens of the West American Crepidula onyx. In a series of 10 specimens of this species 3 had a well-developed notch in the septum, 2 had this feature entirely absent, whilst in the remainder only a slight sinuosity was apparent. In a series of 9 specimens of Crepidula glauca from Dunedin Bay, Florida, not one showed any signs of a notch in the septum.

The authors so far have not been able to compare the dentition of our New Zealand species with that of typical Crepidula in order to ascertain the true systematic value of the features of the septum. Dr. Marwick, however, has found the New Zealand Tertiary crepidulids very constantly to possess a gently concave septum with a shallow median sinus, not in the form of a shallow sigmoid curve as in typical Crepidula.* Personal communication. See also Trans. N.Z. Inst., vol. 59, 1929, p. 918. In view of this constancy in the Tertiary series, the best course appears to be to admit Maoricrypta Finlay to subgeneric rank. Crepidula (Maoricrypta) aff. opuraensis Powell and Bartrum. 1928. Crypta opuraensis Powell & Bartrum, Trans. N.Z. Inst., vol. 59, p. 145, Fig. 25. The Oneroa shells are probably a new species related to both C. densistria Suter (N.Z. Geol. Surv. Pal. Bull. No. 5, 1917, p. 10) and Crypta opuraensis (P. & B.), but as good series of these two latter species are not available to the writers for comparison they have refrained from listing the Oneroa shells as a new species, though they have considered it advisable to publish a description and figures of them. The Oneroa shell (Figs. 37, 38) is usually a large broadly-arched sub-ovate crepidulid, but convexity and outline vary with habitat in the usual manner. Beaks small, sharp, straight and sub-central in most of the specimens. Ornamentation is highly varied in the juvenile stages, but appears to become stabilized in the adult. Juvenile forms may be either radiately ribbed or smooth; there is often an abrupt change from smooth to radiate growth, and even the reverse change may be seen, though somewhat rarely. In the adult the radial sculpture gradually becomes obsolete laterally, especially on the right side, which is practically smooth. On the middle dorsal area there are a number (usually about 9) of strong radial ribs somewhat variable in strength and spacing in different specimens. The ribs are rounded and separated by furrows sub-equal to them in strength. The shell has crowded growth-lines which yield thin imbricating lamellae in some specimens. Septum large and broadly arcuate, almost straight. Dimensions of specimen of Fig. 37 (slightly imperfect): Actual length, 39 mm.; estimated complete length, 50 mm.; breadth, 36 mm. Dimensions of imperfect specimen of Fig. 38: 41 mm. × approximately 27.5 mm. One large individual measures 48 mm. × 29 mm. Crepidula (Maoricrypta) aff. costata Sowerby. A single specimen of a crepidulid very close to costata was collected, but differs in its small straight beaks, which lack the curvature shown by those of this species, and in its radial ornamentation, which is more regular than in costata, and not so imbricated by concentric

growth-lines. It is considered undesirable to institute a new species until further material is available, especially in view of the fact that the Recent species shows such great variation. Genus Polinices Montfort, 1810. This generic name is used in preference to Uber Humphreys, 1797, in accordance with Opinion 51 of the International Commission on Zoological Nomenclature. See Marwick, Trans. N.Z. Inst., vol. 59, 1929, p. 918. Polinices oneroaensis n. sp. (Figs. 59–61). A moderately large ovate naticid very close to P. unisulcatus (Marwick) (Trans. N.Z. Inst., vol. 55, 1924, p. 562). Shell of 5 ½ whorls, including the protoconch, which consists of 1 ½ flat whorls and is small. Spire fairly sharply conical; body-whorl large, strongly inflated, but flattened in middle forming faint obtuse upper and lower angles, the upper one at the suture as it leaves the aperture. From the lower angle the outline of the body-whorl descends gently convex to form a narrowly rounded curve with basal margin of aperture. Suture shallowly abutting. Aperture relatively small, ovate, narrowing above, but wider and rounded below. Outer lip normal, thin, slightly retracted towards suture. Inner lip has umbilical cleft very similar to that of P. unisulcatus (Marwick), but the callus pad is much heavier, completely covering the umbilicus, and does not enter inner lip so steeply, especially in its upper portions. Umbilical cleft rather deep and narrow, long and slightly arcuate; somewhat oblique to inner lip and terminating very close to it. Dimensions of holotype: Height, 22.5 mm.; diameter, 17.9 mm. Figured paratype: 34.8 mm. 24.4 mm. Both holotype and figured paratype are in the A.U.C. collection. The shell is very plentiful at Oneroa, and reaches dimensions even larger than those of the figured paratype, though more often it is small. Even small apparently juvenile specimens invariably show a very heavy umbilical callus, and biangulation of the body-whorl. Genus Cymatium Bolten, 1798. Cymatium tetleyi n. sp. (Figs. 87, 88). This new species is probably ancestral to waterhousi Ad. and Ang. (P.Z.S., 1864, p. 35), which is considered by Powell (Trans. N.Z. Inst., vol. 57, 1926, p. 560) to suggest along with others that migration of larval forms has been proceeding through the agency of the East Australian current. Finlay (Gedenkboek Verbeek, 1925, p. 166) from consideration of the Tertiary molluscs of New Zealand dates this Australian current as from the Pliocene or the Pleistocene. C. tetleyi n. sp. is a very solid sub-pyriform strongly costate and varicate shell with relatively small, fairly sharply conical spire and large body-whorl.

Whorls about 7, but apex incomplete. Outline of spire-whorls obscure owing to wear of early whorls, but apparently gently and regularly convex. Outline of body-whorl fairly regularly convex, contracting on base. Height of spire a little more than aperture and canal; apex acute—much more so than in waterhousi. Suture undulating in consequence of strong axial costae. Prominent spiral sculpture also present. Axial sculpture of strong rounded costae and 4 elevated, rather narrow sub-vertical varices, that on the body-whorl being particularly emphasized. The first varix is at outer lip followed by another to left of aperture on body-whorl, the third midway on penultimate whorl and the fourth, best shown by a paratype, about the beginning of the antepenultimate. The costae are very prominent on the spire-whorls and upper part of body-whorl; about 10 (11 on a mature-paratype) on penultimate whorl. They tend to become obsolete on base and ventral portion of body-whorl above inner lip. Spiral sculpture of raised rounded keels with intervening closely-spaced spiral cords, both faintly crenulated at intersections of growth-lines. They surmount the costae and varices, inducing a tubercular effect, which is especially prominent at the outer lip. There are three keels on penultimate whorl, obscured and reduced in places to 2 by upward expansion of undulating suture. On body-whorl there are 3 keels on shoulder, crossing the costae and producing tubercles of varied strength, whilst lower down and on base there are 3 others interrupted towards aperture by faint axial sculpture. At varix of outer lip these keels are produced into strong rounded blunt spines. Spiral cords between keels of variable number—from 4 to 7— and specially prominent on base. Aperture relatively small, ovate-pyriform, well notched posteriorly, with elongated low tubercle on either side of notch. Anterior canal very narrow, deep and short, slightly oblique to left and bent back. Outer lip somewhat expanded with sharp raised edge separating it from varix; internally polished and with distinct low crenulations alternating with spines of varix; descends fairly straight from suture and is moderately regularly convex below, but has minor sinuosity throughout. Inner lip smooth, wide-spread; callus light on concave parietal wall, but thickens on columella forming a thin lancet-shaped plate which has its point ending about the middle of anterior canal and tends to leave a faint chink against the imperfectly-defined fascicle. Holotype in A.U.C. collection. The species has been named after Mr. E. W. Tetley, who first brought the occurrence of the fossiliferous horizon at Oneroa to the notice of the authors. Genus Charonia Gistel, 1848. Subgenus Charoniella nov. Type: Charonia (Charoniella) arthritica nov. The new species described below is undoubtedly congeneric with Austrotriton neozelanica Marshall and Murdoch and Charonia clifdenensis

Figs. 1 & 2.—Charonia (Charoniella) arthritica n. sp. Holotype. Figs. 3 & 4.—Diplomitra waitemataensis n. sp. Holotype. Fig. 5.—Austrosipho (Verconella) exoptatus n. sp. Paratype. Fig. 6.—Austrosipho (Verconella) exoptatus n. sp. Holotype.

Figs. 7 & 8.—Bembicium priscum n. sp. Holotype. Figs. 9 & 11.—Struthiolaria lawsei n. sp. Holotype. Fig. 10.—Struthiolaria lawsei n. sp. Paratype. Fig. 12.—Cellana thomsoni n. sp. Holotype. Figs. 13 & 14.—Austrofusus (Neocola) oneroaensis n. sp. Holotype.

Figs. 15 & 16.—Baryspira platycephala n. sp. Holotype. Figs. 17 & 18.—Baryspira platycephala n. sp. Paratype. Fig. 19.—Turritella (Maoricolpus) waitemataensis n. sp. Holotype. Fig. 20.—Turritella (Maoricolpus) gittosina n. sp. Holotype. Fig. 21.—Turritella (Zeacolpus) tetleyi n. sp. Holotype. Fig. 22.—Turritella (Zeacolpus) tetleyi n. sp. Paratype. Figs. 23 & 24.—Navicula waitemataensis n. sp. Holotype.

Figs. 25 & 26.—Estea verticostata n. sp. Holotype. Figs. 27, 28 & 31.—Zefallacia benesulcata n. sp. Paratypes. Figs. 29 & 30.—Zefallacia benesulcata n. sp. Holotype. Fig. 32.—Pyrazus consobrinus n. sp. Holotype. Fig. 33.—Pyrazus consobrinus n. sp. Paratype. Fig. 34.—Pyrazus waitemataensis n. sp. Holotype.

Figs. 35 & 36.—Cardium (Trachycardium) greyi Hutton. Piesietype. Figs. 37 & 38.—Crepidula (Maoricrypta) aff. opuraensis Powell & Bartrum.

Figs. 39 & 40.—Cardium (Trachycardium) greyi Hutton. Fig. 41.—Melliteryx mirificus n. sp. Holotype. Fig. 42.—Operculum of Turbo—possibly Sarmaticus? superbus (Zittel).

Fig. 43.—Sigapatella patulosa n. sp. Holotype. Fig. 44.—Sigapatella subvaricosa n. sp. Holotype. Fig. 45.—Zegaterus peramplus n. sp. Holotype. Figs. 46 & 47.—Mytilus tetleyi n. sp. Paratypes. Figs. 48 & 49.—Austrotoma excavata (Suter).

Figs. 50 & 51.—Ischnochiton vetustus n. sp. Holotype. Figs. 52 & 53.—Ischnochiton maorianus Iredale (Recent). Fig. 54.—Macoma robini Finlay. Figs. 55 & 56.—‘Guraleus’ sepelibilis n. sp. Holotype. Figs. 57 & 58.—‘Guraleus’ sepelibilis n. sp. Paratype.

Fig. 59.—Polinices oneroaensis n. sp. Paratype. Figs. 60 & 61.—Polinices oneroaensis n. sp. Holotype. Fig. 62.—‘Macoma’ oneroaensis n. sp. Holotype. Fig. 63.—Modelia aff. granosa (Martyn).

Fig. 64.—Ostrea (Gigantostrea) gittosina n. sp. Paratype. Fig. 65.—Ostrea (Gigantostrea) gittosina n. sp. Holotype. Figs. 66 & 67.—Cylichnina enucleata n. sp. Holotype. Fig. 68.—Cylichnina soror (Suter). Topotype.

Fig. 69.—Isognomon oneroaensis n. sp. Paratype. Figs. 70–73.—Dosinia (Raina) bensoni Marwick. Fig. 74.—Bankia turneri n. sp. Holotype. Fig. 75.—Bankia turneri n. sp. Paratype. Fig. 76.—Macoma hesterna n. sp. Holotype.

Fig. 77.—Acteon oneroaensis n. sp. Holotype. Fig. 78 & 79.—Acteon oneroaensis n. sp. Paratypes. Figs. 80 & 81.—Cominella (Paracominia) finlayi n. sp. Holotype. Fig. 82.—Cominella (Paracominia) lignaria n. sp. Paratype. Figs. 83 & 84.—Cominella (Paracominia) lignaria n. sp. Holotype.

Figs. 85 & 86.—Xymenella asperula n. sp. Holotype. Figs. 87 & 88.—Cymatium tetleyi n. sp. Holotype. Fig. 89.—Lutraria trapezoidalis n. sp. Paratype. Fig. 90.—Lutraria trapezoidalis n. sp. Holotype.

Figs. 91 & 92.—Murexsul echinophorus n. sp. Holotype. Figs. 93 & 94.—Buccinulum (Evarnula) tetleyi n. sp. Holotype. Figs. 95 & 96.—Zeatrophon waitemataensis n. sp. Holotype.

Figs. 97 & 98.—Lepsiella intermedia n. sp. Paratype. Figs. 99 & 100.—Lepsiella intermedia n. sp. Holotype. Figs. 101 & 102.—Lepsiella maxima n. sp. Holotype.

Fig. 103.—Mytilus tetleyi n. sp. Holotype. Figs. 104 & 105.—Morum (Oniscidia) harpaformis n. sp. Holotype. Fig. 106.—Isognomon oneroaensis n. sp. Holotype.

Fig. 107.—Eucrassatella cf. attenuata Hutton. Fig. 108.—Scalpomactra biconvexa n. sp. Holotype. Fig. 109.—Leptomya waitemataensis n. sp. Holotype.

denesis Finlay. In referring both these species to Charonia, Finlay (Trans. N.Z. Inst., vol. 54, 1924, pp. 461–464) admits the difficulty of separating the various genera of the family. Typical Charonia is a large symmetrical shell with a large aperture and moderately expanded outer lip; in Austrotriton and Charoniella, however, the shell is small, invariably distorted and with small aperture not projecting beyond the penultimate whorl, whilst the sculpture is in the form of close granulated spiral threads. Charoniella differs from Austrotriton and comes much nearer to Charonia in the form of the varices, the less-twisted canal and the presence of denticles on the lower columellar lip. Juvenile specimens of Charonia, it may be remarked, do not compare well with Austrotriton or Charoniella, for they are more symmetrical and less distorted. Charonia (Charoniella) arthritica n. subgen. and n. sp. (Figs. 1, 2). A solid tuberculate and varicate elongate sub-pyriform turretted shell, with conical spire about equal in height to aperture and canal. Known by a single specimen. Apical whorls badly eroded: about 7 adult whorls indicated. Outline of whorls irregular: nodular sections angled at one-quarter height above suture; plain sections almost flat. Suture undulating. Body-whorl with strong tubercular angle a little above middle, with concave shoulder above tubercles; a little below this there is an obsolescent faint angle below which there is almost straight or lightly convex moderately rapid descent at the base. Axial sculpture of varices and weak axial costae produced below at angle into prominent rounded tubercles or nodules in series of 4 or 5 alternating with spaces about one-third whorl in extent free from such nodules. These blank spaces alternate with varices and each represents a ventral surface developed during an appropriate growth-stage. The nodules are also absent near the outer lip. Varices are prominent only on later whorls; apparently about 1 per whorl. They are sub-vertical, broad and low: that near inner lip of holotype has its outer (left) margin sharply defined and slightly raised, whilst its inner margin fades into inner lip and body-whorl; it is covered by slightly-raised callus-plate of lower inner lip and gradually wedges out against the fasciole, from which it is separated by a groove oblique to the right. Other varices are ill-defined at their margins. Highly characteristic spiral sculpture of flat-topped threads (about 24 on penultimate and 65 to 70 on body-whorl), reticulated by oblique shallow linear grooves more or less coincident with growth-lines. The spiral threads are stronger and the reticulate structure faint on fasciole. On lower subsidiary angle of body-whorl, to left of varix, a row of 3 nodules has developed closer-spaced than at main angle, whilst the initiation of a still lower equi-spaced nodular series is indicated by a single small but sharp nodule immediately against, the varix. Aperture small, ovate, with a fairly narrow, rather deep posterior canal above, whilst the anterior canal (imperfect) is indicated as

narrow, short and slightly recurved; it is apparently only shallowly notched below, for the broad low fasciole is not separable from the base. A very prominent tubercle margins the inner side of upper canal, whilst near the outer lip there are 7 small elongate internal denticles. Outer lip sharp, though strengthened by adjacent low, ill-defined varix in holotype. Inner lip with about 3 oval rounded tubercles on lower portion; narrow and lightly-spread callus on parietal wall, thickened into plate below on pillar with strong raised outer edge. Parietal wall concave and continuous in curve with the columella, which is flexed to right. Ventral surface of body-whorl above aperture free from axial ornamentation. Dimensions of holotype (in collection of A. W. B. Powell): Height, 50 mm.; breadth, 26 mm. The new species stands nearest to Austrotriton neozelanica Marshall (Trans. N.Z. Inst., vol. 54, 1923, p. 129), which Finlay (Ibid., vol. 55, 1924, p. 464) has referred to the genus Charonia. Genus Morum Bolten, 1798. Subgenus Oniscidia Sowerby. Type: Morum cancellatum Sowerby. Recent species of this genus are confined to warm seas, for about 10 living species are known and all are limited to the West Indies, Gulf of California, China Seas or North Australian waters. A specimen discovered at Oneroa adds a genus and a species to our New Zealand fauna. Morum (Oniscidia) harpaformis n. sp. (Figs. 104, 105). The only specimen so far obtained is badly crushed, but nevertheless sufficiently well-preserved to furnish a reliable description. Shell is of moderate size, ovate-cylindrical. Spire short, about one-fifth of aperture. About 5 adult whorls; protoconch missing. Body-whorl large, cylindrical, with sub-parallel sides; sub-angled above and contracting slowly below to a prominent fasciole. Sculpture consists of 9 heavy, broadly-rounded arcuate axial costae, with narrower interspaces, diminishing and recurving towards fasciole. There is a wide space equal in width to that of two axials between the last rib and the labial varix. The whole shell is ornamented by flat-topped spirals, each bearing 3 closely-spaced spiral threads. About 12 groups of these triplet spirals on body-whorl, separated by equal interspaces. Fasciole distinct, showing arcuate growth-periods; strongly and obliquely flexed to left. Aperture long and narrow with parallel sides; produced below into a short open deeply-notched canal. Outer lip appears as a thickened heavy varix bearing 14 prominent denticles on its inner margin. Inner lip narrowly spread as a heavy callus over parietal wall and inner margin of fasciole and showing a few faint irregular ridges below. Dimensions of holotype (badly crushed): Height, 33.5 mm.; diameter, 21 mm. The holotype is the only specimen and is in the collection of A. W. B. Powell.

Genus Pyrgulina A. Adams, 1863. Pyrgulina cf. pseudorugata Marshall and Murdoch, 1921. (See Trans. N.Z. Inst., vol. 53, p. 83). The type comes from Target Gully (Awamoan), Oamaru. One specimen was found at Oneroa which differs from the type in having 7 instead of “about 5” spirals on the penultimate whorl. In addition its lower spiral is very close to the lower suture and the upper one borders the sutural cord. A worn specimen would no doubt appear to have about 5 more or less distinct spirals as in the type specimen. Genus Diplomitra Finlay, 1926. Finlay has recently (Trans. N.Z. Inst., vol. 57, 1926, p. 408) established the genus Diplomitra to include several of the Mitridae described by Marshall (Ibid., vol. 50, 1918, p. 266) from Pakaurangi Point as Cymbiola masefieldi, C. nitens and C. calcar. So far as is known the genus has not previously been found in New Zealand elsewhere than at Pakaurangi Point. A new species is, however, now described from Oneroa and is very similar to D. masefieldi (Marshall). Diplomitra waitemataensis n. sp. (Figs. 3, 4). A narrowly fusiform turretted shell, with long, faintly gradate spire and long body-whorl, this latter about three-quarters the height of shell. Height of spire about that of aperture and canal. Apex imperfect. Whorls about 7, with sharply-rounded angle just below impressed suture; below the angle the outline of spire-whorls is almost flat and vertical. Body-whorl sub-cylindrical; outline flattened above and then slowly descending, gently convex, at base. Ornamentation: Spire-whorls and upper part of body-whorl smooth except for dense sinuous growth-lines; spiral sculpture appears on base and fasciole as regularly-spaced, fairly strong slightly undulating spiral threads, which tend to become faint, almost obsolete, towards outer lip. There are 5 distinct threads on fasciole and 8 above this on base, the uppermost very faint. Fasciole ill-defined, sinuous, very little elevated, narrow, rounded; it is sub-parallel below to anterior canal, but its obliquity increases above. Aperture narrow, elongate; imperfect above, but apparently with broadly open notch; below it passes imperceptibly into a broad, open anterior canal, imperfect at base. Outer lip thin, with a narrow arch above over posterior notch, and then very gently convex and very little oblique to left. In the figure there is much matrix adherent to its inner surface. Inner lip has very narrow thin callus; it is very lightly excavated at parietal wall, and then passes rapidly to straight columella slightly oblique to the left. Finlay stresses the fact that in adult shells of Diplomitra only the upper columella plait remains. The

present shell is in agreement with this criterion, the plait being very poorly represented. Dimensions of holotype (the only specimen): Height, 41 mm. diameter, 18.6 mm. The holotype is in the collection of A. W. B. Powell. Genus Austrosipho Cossmann, 1906. Finlay (Trans. N.Z. Inst., vol. 57, 1926, pp. 503–504) establishes Cossmann's name Austrosipho with full generic significance to include an Australian series of shells very close to Verconella Iredale, 1914 but differing in nuclear and other characters. He points out also that even if separation of the groups Austrosipho and Verconella is not accepted, the former name has priority over the latter. Austrosipho (Verconella) exoptatus n. sp. (Figs. 5, 6). Fusiform costate shell of moderate size for the group, with conical spire sub-equal in height to aperture without canal. Spire-whorls angled and distinctly keeled a little below middle; slightly concave at shoulder, almost flat below. About 7 post-nuclear whorls; apex missing. Suture undulating, appressed. Body-whorl moderately inflated, large and elongate, with a strong keeled angle above and a fainter one with prominent rounded, somewhat nodular keel below this at the level of the posterior canal. Shoulder decidedly concave. Whorl descends slowly from upper angle to base. Axial sculpture of regular broad rounded ribs (10 in antepenultimate whorl) which are inclined to be nodular at the angle; on body-whorl these continue down to lower angle, but are obsolete on base. Spiral sculpture on whole shell of strong close-spaced lirae (about 3 per mm.). In addition the spire-whorls have a prominent raised thread at the angle which surmounts the nodules and strengthens considerably on the body-whorl. Below this on the body-whorl there are 4 or 5 sub-equidistant similar but more rounded and stronger carinae, the upper two decidedly nodular at the costae, those on the base not so. Aperture fairly narrowly ovate, narrowly notched above and contracting below to a very long open fairly narrow anterior canal. This is obliquely arched to the left, strongly recurved and distinctly notched at the base, yielding a fairly smooth and narrow rounded raised fasciole which passes up close to pillar imperfectly separated from this latter. Outer lip (paratype) thin at edge, strongly angled above and concave at the shoulder; it is gently convex below the shoulder, though with minor sinuosity at spiral keels in younger paratypes; imperfect in holotype. Inner lip is spread as a narrow glaze-on parietal wall and on columella, though it forms a thin narrowly-pointed plate on pillar of some mature paratyes. Columella erect and straight above, but below strongly flexed to the left and slightly to the rear.

Dimensions of holotype (apex missing): Height, 79 mm.; diameter, 37 mm. Holotype and figured paratype (incomplete—71.5 mm. × 32.2 mm.) in collection of A. W. B. Powell. The nearest relative to the new species is an undescribed one from Clifden collected by the late Dr. Allan Thomson, which differs in the feebler development of the keels on the base, but shows otherwise analogous ornamentation. Genus Buccinulum Swainson, 1837. In discussing the genus Euthria, Finlay (Trans. N.Z. Inst., vol. 57, 1926, pp. 414–416) points out the priority of the name Buccinulum over Euthria for the group, and establishes the subgenus Evarnula with Cominella striata Hutton as type. Later (Ibid., vol. 59, 1928, pp. 250–51) he establishes a new subgenus Chathamina and founds the new family Buccinulidae, including Buccinulum in a new sub-family Buccinulinae. In a paper recently published Powell (Trans. N.Z. Inst., vol. 60, 1929, p. 73) has shown that Evarnula and Chathamina must be considered synonymous. A solitary shell from Waiheke, belonging to the ‘compacta’ group of Evarnula, proves to be somewhat related to a newly-described species B. (E.) crassatinum Powell from Ardgowan, Oamaru, and is described below. Buccinulum (Evarnula) tetleyi n. sp. (Figs. 93, 94). Rather small, fusiform, axially costate shell with conical apex, large moderately-inflated body-whorl and strong spiral sculpture. Whorls 6; nucleus imperfect. Spire a little shorter than aperture and canal. Spire-whorls gently convex; suture impressed, undulating. Body-whorl convex above, contracting rapidly at the base to pass down almost straight near pillar. Axial sculpture of broad rounded costae, 9 on penultimate and 8 on body-whorl. They are faint on shoulder of body-whorl, increase at periphery and gradually become obsolete on the base. Spirally ornamented by 15 rather high rounded strong primary threads continued over the neck of the anterior canal, with several (usually 2 or 3) fine intermediate threads; 6 primary spirals on penultimate whorl. Aperture narrowly sub-pyriform with a posterior cleft above and rapidly contracting below to a moderately long open canal gently flexed to the left, slightly bent back and notched below. Outer lip strengthened by a very wide low rounded varix; sharp at its edge; somewhat narrowly convex in outline. Internally the outer lip bears about 10 short stout lirae which do not, however, reach its outer edge. Inner lip strongly concave at parietal wall, with faint denticle above at posterior notch; callus not visible above, but begins as a thin narrow plate on upper part of columella, with 3 low very narrow denticles towards lower canal, the lowest one almost a plait and the most conspicuous. Below on the pillar the callus forms a

thick but very narrow plate. Columella is faintly concave to the right above and flexed gently to the left and back at the canal, where it is closely bordered by a low inconspicuous fascicle sub-parallel to canal. Dimensions of holotype (in A.U.C. collection): Height, 25.5 mm.; diameter, 13 mm. Genus Austrofusus Kobelt, 1879. Austrofusus (Neocola) oneroaensis n. sp. (Figs. 13, 14). Fusiform shell with sculpture of axial costae and strong spiral threads. Spire long, conical, somewhat gradate, about equal in height to aperture and canal in holotype, though a little shorter in one assumed paratype. Whorls (holotype) 5, apex missing. In paratype there are 6½ post-nuclear whorls and about 3 in small conical protoconch. Spire-whorls convex in outline with faint median keeled angle rendered weakly nodulous by fairly strong axial costae. Suture undulating. Body-whorl with strong upper angle below flat or slightly concave shoulder; below the angle the outline at first descends steeply fairly straight, and then bends around convex as it contracts rapidly towards fasciole. Axial costae prominent, becoming fainter below keel as they pass down to suture; 11 on penultimate whorl. The costae die out before reaching base and also become obsolete on later part of body-whorl. Spiral sculpture over whole shell of sharp approximately equidistant raised cords with a variable number (usually from 1 to 3) of extremely fine interstitial threads. Some of cords have a tendency to become stronger on base. An assumed paratype has regular alternation of strong and faint spirals on base and also has a shorter spire than holotype. Aperture small, pyriform, contracting below to a canal which is relatively long for this section of the genus, strongly oblique, decidedly recurved and with deep basal notch. There is a narrow posterior notch due to concave shoulder. Outer lip slightly sinuous, somewhat expanded, thin at edge, but rapidly thickening; strongly lirate within; concave at shoulder and then approximately convex below, passing obliquely towards anterior canal. Parietal wall deeply excavated. Inner lip narrowly spread as thin polished callus, the spiral cords faintly visible beneath; minutely rugose over the fasciole. Pillar erect above and then abruptly twisted to left. Fasciole very prominent and distinct; lamellate, showing traces of coarse spiral sculpture above; bordered against lower part of inner lip and canal by raised ridge running up from left margin of canal and continuous with outer edge of labial callus. Dimensions of holotype: Height, 28.5mm. (apex missing); breadth, 15.5 mm.

The holotype, which is in the collection of A. W. B. Powell, is smaller than some of the imperfect paratypes, which reach an estimated complete height of 45 mm. as compared with 31 mm. (estimated) for the holotype. The new species resembles A. (Neocola) apudalpha Finlay (Trans. N. Z. Inst., vol. 56, 1926, p. 235), but is slenderer and has no axial costae upon the base. Genus Cominella H. and A. Adams, 1853. Subgenus Paracominia nov. Type: Cominella (Paracominia) lignaria n. sp. The shells included here are the most characteristic members of the Oneroa fauna. They are related to Acominia, but are at once separated by the presence of a prominent rounded spiral fold just below the suture and by their small polygyrate smooth three-whorled protoconch. There are two species of this type from Waiheke, whilst there is a third closely-related undescribed form from near Pakaurangi Point, Kaipara, in the N.Z. Geological Survey collection. Cominella (Paracominia) lignaria n. sp. (Figs. 82–84). Turretted sub-pyriform shell of moderate size, with fairly sharp gradate spire and large body-whorl. Spire a little shorter than aperture and canal. 6 post-nuclear whorls; apex incomplete in holotype, but a paratype indicates fairly high, rather small conical apex of probably 3 whorls. Body-whorl sub-cylindrical above; outline convex below a sulcus just beneath the suture, contracting slowly towards a prominent broad basal fasciole. First 3 post-nuclear whorls convex in outline; in other lower whorls the impressed suture is bordered below by a most distinctive broad raised spiral fold. This is followed by a deep rounded median spiral sulcus, causing these whorls to have deeply excavated outline. Axial sculpture of broad rounded fold-like costae (11 on penultimate whorl) very faint on spiral fold and most prominent just below sulcus, where they are often produced into low tubercles, forming a nodular band just above the suture and persistent over body-whorl just above periphery. Costae tend to become obsolete before reaching base. In addition to normal growth-lines, the whole surface of shell is crowded with fine sinuous, occasionally anastomosing, axial grooves which yield a most unusual appearance resembling the grain of wood. The base shows rare traces of obsolete spiral grooves underlying the surface layer, and on some juvenile specimens there is more or less regular spiral ornamentation of fairly close-spaced fine striae. A broad, strongly raised fasciole occupies a great portion of base; it is bordered above by a sharply-raised thread-like ridge towards which the growth-lines are abruptly recurved. Fasciole

convex near upper margin, but soon becomes excavated below, and yields a fairly large false umbilicus where crossed by the overhanging callus-plate of lower mid-portion of inner lip. It is sculptured by transverse lamellae somewhat imbricating on raised portion where they are looped narrowly in correspondence with the deep incision of basal notch, and then retracted upwards towards false umbilicus. Aperture narrowly pyriform, with broad deep posterior notch invading the sub-sutural fold of body-whorl, and a short broadly open anterior canal notched deeply and narrowly below. Outer lip sinuous, thin; narrowly convex over sub-sutural fold. Below this there is a narrow sinus corresponding with spiral sulcus of shell, and then the outline is lightly convex and oblique towards canal. Inner lip has rather limited spread of callus, heavy at anterior canal and below forming a plate bridging the excavation of fasciole and ending at base of the sinuous columella as a narrow sharply-pointed wedge. Parietal wall excavated. Columella vertical above, then flexed strongly to the left and back at the canal. Dimensions of holotype: Height (apex missing), 51.5 mm.; diameter, 25 mm. Holotype and figured paratype (incomplete — 31 mm. × 17.4 mm.) in A.U.C. collection. Along with Struthiolaria lawsei n. sp. this shell is one of the most characteristic of the more abundant of the Oneroa gasteropods. Cominella (Paracominia) finlayi n. sp. (Figs. 80, 81). Fusiform shell of moderate size with sharp turretted straight-profiled spire and convex body-whorl rapidly contracting at the base. 6 post-nuclear whorls; protoconch (paratype) small, sharply conical; about 3 whorls. Spire about three-quarters height of aperture and canal, its outlines almost straight, but, as in lignaria, with impressed suture and a sub-sutural fold, though now almost obsolete, and a spiral sulcus, similarly almost obsolete, beneath it. Both fold and sulcus are distinct, however, on body-whorl. Outlines of spire-whorls nearly flat, the gradate character shown by lignaria having disappeared. Body-whorl fairly tumid at periphery, with strongly convex angle just above suture at aperture; shoulder shallowly and broadly excavated at sulcus. Below angle body-whorl tapers almost straight towards fasciole. This latter is large, but much smaller and less elevated and prominent than in lignaria, and the false umbilical cavity is therefore obsolete; its upper marginal cord is more elevated and distinct than in the latter species. There is flexing and looping of growth-lines as in lignaria, but their retraction on the shallow, almost obsolete excavation of the lower portion of the base is not nearly so striking. Axial sculpture of broad rounded more or less axially-aligned costae is strong in early whorls, but decreases until it is obsolete

on body-whorl of mature specimens, though the sub-sutural fold may be slightly undulating where it crosses the stronger earlier costae of the penultimate whorl. 9 costae on penultimate and antepenultimate whorls. Spiral sculpture generally fairly prominent on base, though irregularly covered by upper shell layer. Sometimes regularly developed as close regularly-spaced grooves on spire of less mature specimens, which have also very strong rounded axial costae over all whorls and are separated only with difficulty from juvenile forms of lignaria. Aperture practically as in lignaria, except that posterior notch is now narrower as result of less elevation of sub-sutural fold, whilst sinus of outer lip at the excavated shoulder of body-whorl is much broader and shallower. Dimensions of holotype (in A.U.C. collection): Height, 49 mm.; diameter, 24.5 mm. The species has been named in honour of Dr. H. J. Finlay, whose monumental work upon Tertiary mollusca is of incalculable value to New Zealand geology. It differs from lignaria in its more spindle-shaped outlines, its less exaggerated spiral fold and sulcus and especially in its lack of the unique minute surface ornamentation possessed by the other species. Genus Murexsul Iredale, 1915. The name Murexsul was originally proposed as a sub-generic division of Murex by Iredale (Trans. N.Z. Inst., vol. 47, 1915, p. 471), but was given full generic significance by Finlay (Ibid., vol. 57, 1926, p. 487). Murexsul echinophorus n. sp. (Figs. 91, 92). A spinose approximately fusiform shell of moderate size, ornamented by prominent spinose varices. Spire-whorls small, rapidly increasing in size to a large body-whorl. Height of spire (incomplete) is estimated as about equal to that of aperture without canal. Whorls angled a little above their middle, the shoulder relatively free from spines near the suture Outlines of whorls convex, body-whorl contracting gradually at base. The sculpture is of axial varices (10 or 11 per whorl) and of strong spiral ridges (7 primary ones on body-whorl; apparently 3 on spire-whorls) produced into prominent spines where they cross the varices. Spines elongated, not hollow as in octogonus, but filled during growth. Interspaces between major spirals locally indicate subsidiary spirals. Basal portion of body-whorl worn, but has less prominent ornamentation than octogonus. Aperture ovate, apparently narrower than in octogonus, but outer lip is a little crushed. Outer lip also descends more steeply from suture as body-whorl is less inflated; imperfect near suture;

furnished with prominent spines at the spirals. Aperture narrows gradually below to a somewhat short, very narrow, apparently shallow, almost closed canal, oblique to the left and apparently not bent back below. Columella almost vertical; faintly excavated. Inner lip with thin callus on parietal wall descending as a moderately thick narrowing projecting plate over the fasciole, forming a false umbilicus over excavated portion, which is not so open as in octogonus owing to more vertical descent of plate. A narrow elevated convex fasciole-ridge with coarse imbricating lamellae ascends at a small angle with columella from basal notch of anterior canal; excavation on its inner side furnishes false umbilicus beneath callus-plate of inner lip. Dimensions of holotype (A.U.C. collection): Height (incomplete), 45.5 mm.; diameter, 25.5 mm. The Oneroa shell differs from M. octogonus (Q. & G.), in having a shorter and straighter canal, a less inflated outer lip and a more vertical lower inner lip. In addition it has stronger sculpture of close - spaced axial varices, with much stronger, solid and not hollow spines. M. echinophorus approaches M. cuvierensis Finlay (Trans. N.Z. Inst., vol. 57, 1927, p. 487), but differs noticeably in having a prominent spiral row of spines between the shoulder and suture. An undescribed species from Target Gully, Oamaru, in the N.Z. Geological Survey collection is more closely allied to the Recent octogonus than to the Waiheke shell. Genus Zeatrophon Finlay, 1926. In a revision of the genus Trophon Montfort, 1810, Finlay has instituted a group under the generic name Zeatrophon (See Trans. N.Z. Inst., vol. 57, 1926, p. 424) into which certain small trophons from Waiheke fall. Zeatrophon waitemataensis n. sp. (Figs. 95, 96). Small fusiform shell with sharp conical strongly gradate spire, large body-whorl and strong axial costae in addition to spiral threads. Whorls: 3 in protoconch; 5 post-nuclear. Protoconch polygyrate, fairly sharp, with 3 convex whorls. The last half whorl has close-axial growth-threads before it passes into adult sculpture. Adult whorls of spire sharply and carinately angled at middle, the shoulder of the whorls almost flat. Body-whorl continues this angle; it descends steeply convex at first and then becomes concave in outline as it passes into lengthened canal. Fasciole indistinct; not separable from the base. Axial sculpture over the whole shell of prominent sharply-elevated narrow distant ribs (about 11 on body-whorl). These rise upwards into distinct lamellar edges inclined forwards towards the aperture. They are continued on the base, but die out towards the lower end of pillar. Spiral sculpture: On antepenultimate whorl a faint spiral thread may appear midway between keel and lower suture, but is not shown

by holotype. Below keel of body-whorl there are a number of equidistant spiral ribs surmounting the axials; on the holotype there are 4 or 5, the lowest ones faint, but on a paratype there are 6. Aperture sub-pyriform, angled above at the keel, and produced below into a long narrow almost straight canal, slightly oblique to the left and curved gently back towards its lower termination. Outer lip thick, slightly dilated, with a strong labial callus; internally it has 4 strong equidistant denticles. Inner lip formed by narrow thin glaze on the parietal wall and pillar. Columella is straight, slightly oblique to the left and bent back gently; it tapers below to a sharp point. Fasciole inconspicuous, rounded and narrow; almost parallel to the inner lip. Dimensions of holotype (in A.U.C. collection): Height, 11.75 mm.; diameter, 6.25 mm. This species is not closely related to any described form, but stands nearest to the Pliocene Zeatrophon bonneti (Cossmann). Genus Xymenella Finlay, 1926. Xymenella asperula n. sp. (Figs. 85, 86). Small fusiform shell with very strong axial costae, sharp conical spire and fairly large body-whorl. Apex missing; about 4 ½ whorls showing. Spire (incomplete) a little shorter than aperture and canal, fairly acute; spire-whorls convex, with a rounded angle developed at the middle of the penultimate and body-whorl. Suture impressed. Body-whorl convex on shoulder, then descending steeply and later contracting rapidly at base, becoming concave in outline as pillar is reached. There is a very strong unusually wide varix to left of inner lip, and what appears to be a faint one on the third visible whorl, whilst the outer lip is strengthened by another strong broad varix with a sharply-raised ridge-like crest near its outer edge. Axial sculpture of narrow strong sharply-raised sub-lamellar ribs not surmounted by the spiral ornamentation and in continuous sub-vertical series; 13 on penultimate and body-whorls. Spiral ornamentation of 2 strong threads on spire-whorls, 6 on body-whorl, the uppermost at the angle. Aperture ovate, angled below suture, and narrowing to pass below into a moderately long open canal which is slightly oblique to the left, almost straight and distinctly bent back. Outer lip is angled at the shoulder and then closes in broadly convex to anterior canal; it is greatly thickened by the marginal varix and internally has 5 strong denticles. Inner lip has thin narrow callus on faintly concave parietal wall and on pillar. Columella straight and vertical above, flexed gently to the left and back below. Fasciole ill-defined, low, rounded, close to inner lip and only slightly oblique to it. Dimensions of holotype: Height (incomplete), 10 mm.; diameter, 4.75 mm.

The holotype (the only specimen) is in the A.U.C. collection. This shell shows relationship to X. minutissima (Suter) from White Rock River, but can be separated by its more heavily variced and dilated outer lip and its narrower and sharper axials. It is also allied to X. inambitiosa Marwick (Trans. N.Z. Inst., vol. 59, 1929, p. 921) from Chatton, but the Chatton shell is proportionately much broader and has a higher and less sloping shoulder. Genus Lepsiella Iredale, 1912. Lepsiella maxima n. sp. (Figs. 101, 102). Shell large for the genus, pyriform, heavy and solid, spirally ornamented; spire short, faintly gradate, wide-angled with acuminate apical whorls (paratype). Spire outline slightly concave near acuminate apex, almost flat below. Spire about one-half the height of aperture and canal. About 5 post-nuclear whorls; apex missing in all specimens. Spire-whorls slightly gradate, concave on shoulder; just above the lower suture there is a low angle which becomes prominently keeled on body-whorl. Below this there are 3 widely- and evenly-spaced low obscure ridges corresponding to the keels of scobina the genotype. On the base there is a prominent very abruptly elevated rather narrow fasciole strongly oblique to inner lip and recurved sharply to basal notch of anterior canal; it is laminated by imbricating growth-lines on some paratypes. Between it and the callus-plate of the inner lip there is an excavated hollow into which the growth-lines are bent upwards and which yields a false umbilical chink. Ornamentation: On early gradate spire-whorls there are about 8 fairly strong axial costae only visible on well-preserved specimens. Nearly all of shell is ornamented by regular close, raised, spiral riblets, with interspaces sub-equal to ribs, which are faintly imbricated by numerous growth-lines and often interrupted at fairly regular intervals by pronounced growth-rest-stages. About 10 spirals on the shoulder, with a total of about 40. Aperture narrowly ovate with no distinct posterior notch; it narrows below to a short canal, relatively narrow in mature holotype, a little oblique to the left and retracted and deeply and narrowly notched at the base. Outer lip very thick in mature shells, expanded, regularly arcuate internally, but angled externally at keeled shoulder of body-whorl. Internally it is shallowly grooved transverse to the margin, near its outer edge. Inner lip relatively narrow, smooth, with very thin smear of callus on the excavated parietal wall, but thickening below on the columella to form a thick tongue-like plate which tapers out to a point on the pillar near the base of anterior canal. Where the plate bridges the depression below the raised fasciole, there is the chink-like hollow already noted. Columella straight above, but bent gently to the left below. Dimensions of holotype (in collection of A. W. B. Powell): Height, 56.5 mm.; diameter, 38.5 mm.

Lepsiella intermedia n. sp. (Figs. 97–100). This species of Lepsiella is similar in many respects to the previous one, but appears to be smaller and lacks the prominent keel on the body-whorl, which is more roundly inflated, and the false umbilical depression. Holotype imperfect; apical whorls missing, 4 ½ showing. Spire-whorls acuminate. Outline of shell concave over spire-whorls, strongly convex over body-whorl, which is broadly sub-angled above. Body-whorl with 41 closely-spaced rounded spiral cords with interspaces almost linear. There is a prominent low rounded narrow fasciole on the base, but less oblique to the inner lip than in maxima and without the distinct hollow between it and the lip, so that the chink below the callus-plate of inner lip is not developed. The fasciole is devoid of sculpture other than growth-lines. Aperture much as in other species, though the outer lip is more regularly convex and only slightly angled at the shoulder, and the inner lip has a somewhat thinner callus on the pillar. Dimensions of holotype (in collection of A. W. B. Powell): Height, 40 mm.; diameter, 24 mm. Figured paratype (juv.; in collection of A. W. B. Powell): 19 mm. × 12.5 mm. The two species maxima and intermedia are confidently ascribed to Lepsiella in spite of their greater adult size, and the fact that the apical whorls are not preserved. L. maxima n. sp. has the same type of sculpture as the genotype, namely, a peripheral keel and 3 minor ridges or keels below. The fasciole, however, is more strongly oblique to the inner lip, leaving a false umbilical chink after recurving to the basal notch. This feature, nevertheless, is variable in its development. In the second species, intermedia, which is constantly smaller, the fasciole is less oblique and lacks the false umbilical chink, so that it more closely resembles the genotype. Genus Baryspira Fischer, 1883. Baryspira platycephala n. sp. (Figs. 15–18). A moderately large elongate-oval shell with low conical to domeshaped spire about one-third the height of aperture. Spire-whorls covered with heavy callus which almost obliterates upper depressed band and in front in holotype continues down as a thick wide pad bordering the inner lip almost to the pillar, though not so far in a less-developed paratype. Body-whorl descends at first straight and then contracts slowly towards base. Its smooth central band is bordered below by a moderately wide depressed band with a raised rounded wider band between this and a second somewhat wider depression proceeding from anterior notch. Aperture narrow with sub-parallel sides; deeply and broadly notched below and channelled above by a deep groove extending upwards over spire-callus. Columella short, concave, twisted strongly forward below and expanded by callus which is traversed by two oblique narrow folds and marked off from the base by a rather narrow

sulcus. Inner lip oblique; above has a thick callus-pad which terminates abruptly before reaching crest of dorsal surface. Dimensions of holotype: Height, 28.8 mm.; diameter, 16 mm. Figured paratype: 25.8 mm. × 14 mm. Holotype (collected by Mr. C. R. Laws) in A.U.C. collection. This species is closely related to Baryspira tirangiensis Marwick and, more distantly, to B. robusta Marwick. It differs from both in its smaller adult size and greater spread of spire-callus. Genus Austrotoma Finlay, 1924. Austrotoma excavata (Suter). A description and figures of a variant of the above species from the Waiheke beds are here given. Another specimen from Waiheke compares well with Suter's description and figure of the type from the lower Komiti Point (= Pakaurangi) beds, but a third differs from the two forms mentioned in having the spiral sculpture almost obsolete over the spire-whorls, whilst in a further Waiheke specimen the nodules extend well over the penultimate whorl. All specimens agree in having at the shoulder a broad prominent keel which is nodulous on the early spire-whorls. Description of Waiheke Specimen (Figs. 48, 49). Sub-fusiform elongate shell with long turretted somewhat gradate spire and sub-cylindrical body-whorl. Spire a little less in height than aperture. Whorls about 9, including apex. Protoconch elevated, conical; there are about 3 smooth whorls and then weak spiral ornamentation begins, but separation of apical whorls from early spire-whorls is indistinct in the figured specimen. Spire-whorls strongly angled and keeled a little below the middle, with distinct spiral furrow at the concave shoulder, leaving, just below suture, a faint fold from which the growth-lines are acutely bent forwards; flat and sub-vertical in outline below the angle. Body-whorl has corresponding keeled angle and concave shoulder, below which it is gently convex, narrowing slowly to base. Axial sculpture of weak costae (about 13 per whorl) in earlier spire-whorls, rapidly decreasing until they have practically disappeared after about the third post-nuclear whorl. Spiral ornamentation of a broad flat carina at angle of later whorls rendered nodulous over the first three and a half post-nuclear ones by the crossing of axial costae. Above the carina there are numerous very fine spiral threads minutely reticulated by sinuous growth-lines. Below the carina of lower spire-whorls there are 3 strong spiral cords with intervening fine spiral striae—only 1 in figured specimen, but as many as 3 in others. On body-whorl, including base, there are 13 low flat prominent spiral cords with sub-equal interspaces.

Aperture narrowly elongate; it is narrowly notched below into short broadly open basally-notched anterior canal. Outer lip thin, somewhat crushed in figured specimen; very gently convex, but with narrow sinus at spiral sulcus between suture and shoulder of body-whorl. Inner lip with thin limited callus on parietal wall and columella; parietal wall little excavated. Columella straight and slightly oblique above, but then bent gently to the left and faintly to the rear. Fasciole distinct, relatively broad, not raised, strongly oblique to the columella; poorly preserved in figured specimen. In another specimen shows faint traces of spiral threads and is shallowly excavated against the sharply-defined margin of the base, where there appears to be a faint ridge. Dimensions of figured specimen (A.U.C. collection): Height, 36 mm.; diameter 13 mm. Suter's holotype (imperfect) measures 35 mm. × 16 mm. Only 4 whorls are shown in his figures (N.Z. Geol. Surv. Pal. Bull. No. 5, 1917, pl. 6, figs. 17 and 18). Genus Guraleus Hedley, 1918 (Journ. Roy. Soc. N.S.W., vol. 51, suppl. P.M. 79). “Guraleus” sepelibilis n. sp. (Figs. 55–58). Small elongate-ovate axially costate shell with a conical spire about equal in height to aperture with canal. Whorls 7, including protoconch; this latter conical of 4 smooth convex whorls, rather flattened. Spire-whorls generally convex in outline, but have a narrow distinctive thread-like fold just beneath the suture, and beneath this a distinct narrow concave shoulder bounded below by a rounded angle rendered sub-nodular by the incidence of the axial costae. The body-whorl continues this outline above, but is flatly convex below the angle, contracting somewhat slowly on the base. Axial ornamentation consists of strong costae (10 on penultimate whorl) in sub-vertical series almost continuous except that the costae fade out rapidly on the concave shoulder of the whorls. They are strongest at the angle and decrease in strength and breadth as they pass down on the base. There is also spiral sculpture over the whole shell of strongly-raised close-spaced threads surmounting the costae. They are about 11 in number on the penultimate whorl (upper 4 on concave shoulder) and about 26 on the body-whorl and neck of canal, crowding together on the shoulder and more distant and stronger on the base, where they become slightly reticulated below by the axial sculpture. Lower spirals on base are a little stronger and more closely spaced and continue uninterrupted across the inner lip, forming a weak fasciole. Aperture very narrow, with sub-parallel sides and a narrow deep rounded sinus immediately below suture. It is constricted below to a short narrow open and slightly recurved canal. Outer

lip with moderately narrow and deep rounded sinus at the shoulder after which it is inclined forward below. Parietal wall narrow and deeply excavated over upper portion. Columella sub-vertical, sharply pointed below by a narrow callus extending down inner margin of canal. Dimensions of holotype (in collection of A. W. B. Powell): Height, 6.8 mm.; diameter, 3.1 mm. Paratype (Figs. 57, 58): 7.1 mm. × 3.5 mm.; in A.U.C. collection. The species just described seems to be allied to the New Zealand Tertiary form Mangilia gracilenta Suter. Its location in Guraleus is doubtful. Indeed Hedley's own association of species suggests the need for several genera. The Waiheke shell is certainly not congeneric with the genotype picta Ad. and Ang., but it is here provisionally placed in Guraleus pending the publication of Dr. Finlay's review of the family (See Finlay, Trans. N.Z. Inst., vol. 57, 1926, p. 434). Genus Phenatoma Finlay, 1924. Subgenus Cryptomella Finlay, 1924. Phenatoma (Cryptomella) transenna (Suter). Finlay (Trans. N.Z. Inst., vol. 55, 1924, pp. 515–516) instituted the genus Phenatoma and the sub-genus Cryptomella, and referred to this latter Suter's sub-species Leucosyrinx alta transenna (Suter) (N.Z Geol. Surv. Pal. Bull. No. 5, 1917, pp. 44 & 84) with full specific rank. The Waiheke specimens are generally very uniform, but one or two show additional fine secondary spirals, whilst rarely the lower rounded cord margining the suture is replaced by 2 lesser cords and even by 1 on later whorls. Genus Acteon Montfort, 1810. Acteon oneroaensis n. sp. (Figs. 77–79). Fairly narrowly ovate small shell, with very large body-whorl and a low spire a little less in height than half the aperture. About 5 post-nuclear whorls; nucleus apparently missing. Spire-outline flat. Body-whorl very large and inflated, cylindrical, roundly angled above. On the shoulder it is gently convex and descends from the angle broadly convex with very little contraction to the base. Ornamentation: Smooth and polished, with faint dense growth-lines and strong spiral grooves which are very variable in number. On upper half of spire-whorls (paratypes) there are from 1 to 4 such spiral grooves, the larger number being rare; on the body-whorl these are continued on the shoulder, and then there is a smooth space at the angle and for some distance below it. The grooves then recommence strongly about the level of the top of the aperture. About 12 to 14 are present (12 on holotype); they are sub-equidistant above, but become nearer together on the base.

Aperture narrowly elongate, with long wide cleft above between the thin compressed outer lip and the body-whorl, but widening below where it is bounded by a thickened sharply arcuate basal lip (para-type), which is continuous in a regular curve with the outer lip. Inner lip has a very thin narrow glaze above on the parietal wall. Columella is strongly and obliquely bent to the right as it passes upwards and is continued inwards as a strong plait. Dimensions of holotype (spire missing): Height, 7.2 mm.; diameter, 4.5 mm. Holotype and figured paratype (5.75 mm. × 3.75 mm.) in collection of A. W. B. Powell. Genus Cylichnina Monterosato, 1884. Finlay (Trans. N.Z. Inst., vol. 57, 1926, p. 438) states that Hedley and May have referred Cylichnella pygmaea A.Ad. to the genus Cylichnina Monterosato, and, finding that the New Zealand shells previously referred to this species are not correctly placed there, has described them as a new species C. opima Finlay. There is a Tertiary member of the genus in Cylichnella soror Suter (N.Z. Geol. Surv. Pal. Bull. No. 5, 1917, p. 63). Suter's drawing is misleading and inaccurate, for the columella fold is not nearly so prominent as there shown, so that a figure (Fig. 68) is here published of a topotype from Target Gully. A new related species is plentiful at Oneroa, though the shells have usually been crushed in fossilization. It differs from the two species mentioned above in being shorter and not so cylindrical, and from soror in particular in the feeble development of its columella fold and in the fact that the latter species becomes conspicuously narrower above. Cylichnina enucleata n. sp. (Figs. 66, 67). This species differs from opima in its less cylindrical shorter body-whorl, for this latter contracts rapidly at the inner lip towards the columella. The shell is minute, sub-cylindrical in general form and well inflated; it is widest near its middle height and contracts distinctly above and towards the base. Its apex is hollowed rather narrowly. Aperture longer than the shell, slightly projecting above; very narrow and sub-parallel to the parietal wall in upper half, but expanding below and there terminated by narrowly rounded basal margin. Outer lip thin projecting in a sharp point above, imperfect below; apparently at first it is narrowly convex below the elevated point, and then descends vertically and almost straight to join in the curve of the basal lip. Columella passes up oblique to the right and appears to enter the aperture as an oblique plait distinctly separated from the basal portion of the body-whorl. Dimensions of holotype (in A.U.C. collection): Height, 2.1 mm.; diameter, 1.2 mm.

Class: Amphineura. Genus Ischnochiton Gray, 1847. Ischnochiton vetustus n. sp. (Figs. 50, 51). The only specimen is an anterior valve. The sculpture of the tegmentum consists of about 38 low comparatively broad flexed radiating riblets, with linear interspaces. Three of the riblets bifurcate towards the outer margin. Towards this latter a few irregular concentric growth-lines cause an obscure granulation. Articulamentum with 12 irregularly-spaced small narrow slits continued as rays to the apex and formed of series of closely-spaced interrupted concentric striae. Dimensions of holotype: Height, 2.5 mm.; breadth, 5.5 mm. Type in A.U.C. collection. The anterior valve of this species differs considerably from that of maorianus (5 mm. × 8.75 mm.) in being proportionately shorter and more coarsely sculptured. Compare Figs. 52, 53. List of Mollusca From Oneroa. The location of holotypes and of unique specimens is given in brackets; other species are represented in the collection both of A. W. B. Powell (A.W.B.P.) and Auckland University College (A.U.C.). Class: Pelecypoda. * Species marked with an asterisk are Recent. 1. Nucula cf. nitidula A. Adams. 2. Anomia trigonopsis Hutton. 3. Navicula waitemataensis n. sp. (Holotype in A.U.C. coll.). 4. Mytilus tetleyi n. sp. (Holotype in A.W.B.P. coll.). *5. Musculus cf. impactus (Hermann) (in A.U.C. coll.). 6. Isognomon oneroaensis n. sp. (holotype in A.W.B.P. coll.; paratype in A.U.C. coll.). 7. Lima sp. juv. (indet.) (in A.U.C. coll.). 8. Ostrea (Gigantostrea) gittosina n. sp. (holotype in A.W.B.P. coll.). 9. Eucrassatella cf. attenuata (Hutton) (in A.W.B.P. coll.). 10. Venericardia sp. juv. (indet.) (in A.U.C. coll.). 11. Venericardia sp. juv. (indet.) (in A.U.C. coll.). 12. Chama sp. (indet.) (in A.U.C. coll.). 13. Notomyrtea sp. (indet.) (in A.U.C. coll.). 14. Melliteryx mirificus n. sp. (holotype in A.W.B.P. coll.). 15. Macoma hesterna n. sp. (holotype in A.U.C. coll.). 16. Macoma robini Finlay (in A.W.B.P. coll.). 17. ‘Macoma’ oneroaensis n. sp. (holotype in A.W.B.P. coll.). 18. Leptomya waitemataensis n. sp. (holotype in A.W.B.P. coll.). 19. Scalpomactra biconvexa n. sp. (holotype in A.W.B.P. coll.).

20. Lutraria trapezoidalis n. sp. (holotype and paratype in A.U.C. coll.). * Species marked with an asterisk are Recent.21. Zenatia acinaces (Q. & G.). *22. Dosinia cf. lambata (Gould). 23. Dosinia (Raina) bensoni Marwick. 24. Tawera cf. bartrumi Marwick (in A.U.C. coll.). 25. Cardium (Trachycardium) greyi Hutton. *26. Gari cf. lineolata (Gray) (in A.U.C. coll.). 27. Corbula pumila Hutton. 28. Corbula aff. zelandica Q. & G. 29. Saxicava sp. (in A.U.C. coll.). 30. Panope orbita Hutton (in A.W.B.P. coll.). 31. Bankia turneri n. sp. (holotype in A.W.B.P. coll.). Class: Gasteropoda. 32. Haliotis sp. (indet.) (not collected). 33. Tugali navicula Finlay (in A.W.B.P. coll.). 34. Modelia aff. granosa (Martyn) (in A.W.B.P. coll.). 35. Sarmaticus ? superbus (Zittel) (in A.U.C. coll.). 36. Cellana thomsoni n. sp. (holotype in A.U.C. coll.). 37. Bembicium priscum n. sp. (holotype in A.U.C. coll.). 38. Estea verticostata n. sp. (holotype in A.U.C. coll.). 39. Notosetia cf. stewartiana (Suter) (in A.U.C. coll.). 40. Subonoba aff. fumata (Suter) (in A.U.C. coll.). 41. Nozeba candida Finlay. 42. Zefallacia benesulcata n. sp. (holotype in A.W.B.P. coll.). 43. Pyrazus consobrinus n. sp. (holotype in A.W.B.P. coll.). 44. Pyrazus waitemataensis n. sp. (holotype in A.W.B.P. coll.). 45. Turritella (Maoricolpus) gittosina n. sp. (holotype in A.W.B.P. coll.). 46. Turritella (Maoricolpus) waitemataensis n. sp. (holotype in A.W.B.P. coll.). 47. Turritella (Zeacolpus) tetleyi n. sp. (holotype in A.U.C. coll.). 48. Struthiolaria lawsei n. sp. (holotype in A.W.B.P. coll.). 49. Zegalerus peramplus n. sp. (holotype in A.W.B.P. coll.). 50. Sigapatella patulosa n. sp. (holotype in A.W.B.P. coll.). 51. Sigapatella subvaricosa n. sp. (holotype in A.U.C. coll.). 52. Crepidula (Maoricrypta) aff. opuraensis Powell & Bartrum. 53. Crepidula (Maoricrypta) aff. costata (Sowerby) (in A.U.C. coll.). 54. Polinices oneroaensis n. sp. (holotype in A.U.C. coll.). 55. Cymatium tetleyi n. sp. (holotype in A.U.C. coll.). 56. Charonia (Charoniella) arthritica n. subgen. & sp. (holotype in A.W.B.P. coll.). 57. Morum (Oniscidia) harpaformis n. sp. (holotype in A.W.B.P. coll.). 58. Pyrgulina cf. pseudorugata Marsh. & Murd. (in A.U.C. coll.). 59. Diplomitra waitemataensis n. sp. (holotype in A.W.B.P. coll.).

60. Austrosipho (Verconella) exoptatus n. sp. (holotype in A.W.B.P. coll.). 61. Buccinulum (Evarnula) tetleyi n. sp. (holotype in A.U.C. coll.). 62. Austrofusus (Neocola) oneroaensis n. sp. (holotype in A.W.B.P. coll.). 63. Cominella (Paracominia) lignaria n. subgen. & sp. (holotype in A.U.C. coll.). 64. Cominella (Paracominia) finlayi n. sp. (holotype in A.U.C. coll.). 65. Murexsul echinophorus n. sp. (holotype in A.U.C. coll.). 66. Zeatrophon waitemataensis n. sp. (holotype in A.U.C. coll.). 67. Xymenella asperula n. sp. (holotype in A.U.C. coll.). 68. Lepsiella maxima n. sp. (holotype in A.W.B.P. coll.). 69. Lepsiella intermedia n. sp. (holotype in A.W.B.P. coll.). 70. Baryspira platycephala n. sp. (holotype in A.U.C. coll.). 71. Austrotoma excavata (Suter). 72. ‘Guraleus’ sepelibilis n. sp. (holotype in A.W.B.P. coll.; paratype in A.U.C. coll.). 73. Melatoma cf. awamoaensis (Hutton) (in A.U.C. coll.). 74. Phenatoma (Cryptomella) transenna (Suter). 75. Acteon oneroaensis n. sp. (holotype in A.W.B.P. coll.). 76. Cylichnina enucleata n. sp. (holotype in A.U.C. coll.). Class: Amphineura. 77. Ischnochiton vetustus n. sp. (holotype in A.U.C. coll.). Class: Scaphopoda. 78. Dentalium sp. (indet.) (in A.U.C. coll.). List of Papers Referred To. The following list of papers includes those most commonly referred to in the preceding text:— Dall, W. H., 1923. Additions and Emendations to United States National Museum Bulletin No. 112, Proc. U.S. Nat. Mus., vol. 63, art. 10, pp. 1–4. Finlay, H. J., 1924. New Shells from New Zealand Tertiary Beds, Trans. N.Z. Inst., vol. 55, pp. 450–479. —— 1924. The Molluscan Fauna of Target Gully, Ibid., vol. 55, pp. 494–516. —— 1925. Some Modern Conceptions Applied to the Study of the Cainozoic Mollusca of New Zealand, Gedenkb. Verbeek, Verhand. Geol.-Mijnb. Gen. v. Nederl. en Kolon., Geol. Ser., d. 8, pp. 161–170. —— 1926. New Shells from New Zealand Tertiary Beds: Part 2, Trans. N.Z. Inst., vol. 56, pp. 227–258. —— 1926. A Further Commentary on New Zealand Molluscan Systematics, Ibid., vol. 57, 1927, pp. 320–485. Separates were issued in 1926. —— 1928. The Recent Mollusca of the Chatham Islands, Ibid., vol. 59, pp. 232–286. Iredale, T., 1915. A Commentary on Suter's Manual of the New Zealand Mollusca, Ibid., vol. 47, pp. 417–497. —— 1924. Results from Roy Bell's Molluscan Collections, Proc. Linn. Soc. N.S.W., vol. 49, pt. 3, pp. 179–278.

Marwick, J., 1924. The Tertiary and Recent Naticidae and Naricidae of New Zealand, Trans. N.Z. Inst., vol. 55, pp. 545–579. —— 1927. The Veneridae of New Zealand, Ibid., vol. 57, pp. 567–635. —— 1929. Tertiary Molluscan Fauna of Chatton, Southland, Ibid., vol. 59, 903–934. Marshall, P., 1918. The Tertiary Molluscan Fauna of Pakaurangi Point, Kaipara Harbour, Ibid., vol. 50, pp. 263–278. —— 1923. Early Tertiary Molluscan Faunas of New Zealand, Ibid., vol. 55, pp. 115–121. Marshall, P., and Murdoch, R., 1920. The Tertiary Rocks near Wanganui, Ibid., vol. 52, pp. 115–128. —— 1921. Some Tertiary Mollusca, with Descriptions of New Species, Ibid., vol. 53, pp. 77–84. Powell, A. W. B., 1926. On a Large Tonna and Two Other Gasteropods of Australian Origin, Ibid., vol. 57, pp. 559–562. —— 1929. The Recent and Tertiary Species of the Genus Buccinulum in New Zealand, with a Review of Related Genera and Families, Ibid., vol. 60, pp. 57–101. Powell, A. W. B., and Bartrum, J. A., 1928. Mollusca from Kaawa Creek Beds, West Coast, South of Waikato River, Ibid., vol. 59, pp. 139–162. Smith, E. A., 1915. Mollusca, Part 1—Gastropoda, Prosobranchia, Cephalopoda and Pelecypoda, Brit. Antarc. (“Terra Nova”) Exped., 1910, Nat. Hist. Rep., Zoology, vol. 2, No. 4, pp. 61–112. Suter, H., 1913. Manual of the New Zealand Mollusca (Atlas of Plates, 1915), Government Printer, Wellington. —— 1915. Revision of the Tertiary Mollusca of New Zealand, Pt. 2, N.Z. Geol. Surv. Pal. Bull. No. 3. —— 1917. Descriptions of New Tertiary Mollusca Occurring in New Zealand, N.Z. Geol. Surv. Pal. Bull. No. 5. —— 1918. Alphabetical List of New Zealand Tertiary Mollusca, Government Printer, Wellington. Thomson, J. A., 1919. Polymorphism in the Common New Zealand Limpet, N.Z. Journ. Sci. and Techn., vol. 2, pp. 264–267.