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Volume 59, 1928
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Tertiary Molluscan Fauna of Chatton, Southland.

[Abstract read, by permission of the Director of the N.Z. Geological Survey before the Wellington Philosophical Society, 28th November, 1928; received by Editor, 29th November, 1928; issued separately, 25th March, 1929.]

The object of this paper is primarily a description of the molluscan. fauna of Chatton, eight miles north of Gore, Southland. Field-occurrences and stratigraphical relations are not discussed as such a course would have entailed further delay of a paper promised long ago.

The material belongs to two collections. One was made as far back as 1913 by Mr. R. A. W. Sutherland, now of Wanganui, and was kindly donated by him to the Geological Survey about six years ago in the hope that it would be critically examined. Work has proceeded intermittently on the material as opportunity offered, and the present paper is largely a result of that work.

In 1925 the late Dr. J. Allan Thomson lent to the Geological Survey a large collection gathered by Mr. E. M. Christie, of Gore, who has since then added to his original material. My sincere thanks are due to these gentlemen for providing facilities to describe such an interesting molluscan fauna. The Dominion Museum specimens were prepared by Miss M. Mestayer with great care, and thus were preserved many fragile specimens which would otherwise have been lost.

To clear the ground for discussion of the affinities and age-equivalents of the Chatton fossils it is necessary to discuss Suter's record of 29 per cent. of Recent species Suter's list (1921, p. 95) was prepared from Mr. Sutherland's collection, and most of the manuscript labels are preserved, so that practically all of the indentifications can be cheeked.

It will be seen from the comparative list given below that the results of the re-survey are very different from the original. Suter's conception of fossil species was vague and inconsistent, so that his groups are in general far too wide to be of practical significance. The palaeontological evidence cited by Dr. Marshall (1917, p. 460, p. 465) is therefore badly based, though the Oligocene age allotted to the Chatton beds by him is probably correct.

Accurate correlation of the Chatton sands with other fossiliferous deposits of New Zealand is difficult because of the very large proportion of new species. The assemblage of genera, however, agrees much more closely with that of middle Tertiary faunas (Ototaran to Awamoan) than with early Tertiary ones. This might be claimed to be the result of environment rather than time; but the complete absence of archaic or older Tertiary elements such as Monalaria, Speightia, Aporrhaidae, and Avellanidae, definitely rules out the

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Bortonian and Tahuian stages. The Waiarekan is known only from a relatively small fauna which lived in a somewhat unusual environment, for the fossils occur in the fine tuffaceous calcareous matrix of a coarse igneous conglomerate. The presence of Spirocolpus tophina (Marw.) at both Lorne and Chatton is the only strong connecting link between the two faunas.

Although the generic constitution agrees well with the Awamoan, the consistent differences in related species demand a considerable lapse of time for their development. The absence of such characteristic Awamoan species as Limopsis zealandica Hutton, Turritella (Maoricolpus) cavershamensis Harris, Nassarius socialis (Hutton), Comitas fusiformis (Hutton) is also noteworthy.

Dr. Finlay (1924, p. 534) has already shown from the rich faunas secured by him at Clifden, Southland, that the period of time between the Waiarekan and Awamoan stages, represented by Thomson's Ototaran and Hutchinsonian, was of relatively long duration. It is to the earlier part of this period, i.e., to the Ototaran, that the Clifden fauna probably belongs. Finlay (1924, p. 535) has also correctly drawn attention to the close resemblance of the Chatton fauna to that of the Wharekuri greensand. Many of the common species at both localities are strikingly similar, but yet show important differences of detail. These are differences which may be due to environment, although the time factor has not yet been disposed of.

Revised list of Chatton Mollusca.
(Suter's identifications on the right.)

Nucula tersior n. sp. Nucula hartvigiana
Nucula vestigia n. sp. Nucula n. sp.
Nuculana probellula n. sp.
Cucullaea worthingtoni Hutt.
Glycymeris thomsoni n. sp. Glycymeris subglobosa.
Limopsis parma n. sp.
Anomia n. sp.
Ostrea wollastoni Fin.
Cyclopecten compitum n. sp.
Spissatella poroleda Fin. Crassatellites obesus.
Chattonia animula n. gen. et sp.
Venericardia christiei n. sp. V. ponderosa.
Venericardia pseutella n. sp. V. pseutes.
Venericardia caelebs n. sp. V. difficilis.
Venericardia prolutea n. sp.
Eulopia staminifera n. sp.
Gonimyrtea bucculenta n. sp.
Maoritellina imbellica n. sp. Erycina?
Solecurtus chattonensis Fin.
Gari n. sp. Psammobia n. sp.
*Scalpomactra cf. scalpellum (Reeve).
Zenatia sp.
Paradione cf. parki Marw. Macrocallista multistriata.
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Dosinia sodalis n. sp.
Dosinia imperiosa n. sp.
Kuia cf. vellicata (Hutt.) juvenile.
Turia chattonensis Marw.
Bassina speighti (Sut.)
Corbula canaliculata Hutt.
Corbula pumila Hutt. Corbula pumila.
*Nemocardium aff. pulchellum (Reeve).
Pholadidea increnata n. sp.
Myadora delta n. sp.
Antisolarium vixincisum n. sp. Solariella n. sp.
Elachorbis duplicarina n. sp. Circulus n. sp.
Spirocolpus tophina (Marw.).
Zeacolpus chattonensis n. sp Turritella cavershamensis.
Zeacolpus chattonensis n. sp Turritella concava.
Mesalia striolata (Hutt.) Mesalia striolata.
Struthiolaria subspinosa Marw.
Zefallacia chattonensis n. sp. Nervnea n. sp.
Pyrazus Sutherlandi n. sp. Batillaria pomahakemsis.
Maoricrypta salebrosa n. sp. Crepidula costata. Crepidula gregaria sub sp. nov.
Maoricrypta salebrosa n. sp. Sinum fornicatum.
Sigapatella mapalia n. sp. Calyptraea tenuis
Cochlis notocenica (Fin.) Natica zelandica.
Cochlis consortis (Fin.)
Polinices huttoni v. Iher.
Polinices chattonensis (Marw.)
Polinices cf. lobatus (Marw.)
Polinices incertus (Marw.)
Polinices blaesus n. sp.
Magnatica sutherlandi (Marw.)
Cirsotrema cf. lyratum (Zitt.) Epitonium lyratum. fragment.
Notacirsa n. sp. Turbonilla prisca.
Odostomia alexanderi h. sp. Odostomia bembix.
Syrnola wallacei n. sp.
Syrnola aclyformis n. sp.
Turbonilla chattonensis n. sp. Turbonilla zealandica.
Proximitra incisula n. sp.
Cominella (Cominista) chattonensis (Fin.) Cominella n. sp.
Austrofusus precursor Fin. Siphonalia nodosa.
Xymenella inambitiosa n. sp.
Trigonostoma christiei Fin.
Baryspira robusta (Marw.)
Baryspira electa n. sp. Ancilla papillata.
Erato marshalli n. sp.
Metamelon inermis (Fin.) Mitra n. sp.
Austrodrillia cinctuta n. sp.
Austrotoma inaequabilis n. sp.
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Austrotoma toreuma n. sp.
Phenatoma (Cryptomella) crassispiralis n. sp.
Acuminia transitorsa n. sp.
Acuminia suteri n. sp. Terebra n. sp.
Acteon chattonensis n. sp. Acteon n. sp.
Ringicula castigata n. sp. Ringicula uniplicata.
Bullinella enysi (Hutt.)
Dentalium solidum Hutt. Dentalium solidum.
Rhyssoplax allan-thomsoni Mestayer.

The following species listed by Suter are not included above, for the reasons given in each case: Cardium sp. fragments; Corbula zelandica much too worn for identification but belonging to same group; Cuna sp., Cyamiomactra sp., both young Venerids; Marginella conica, specimen smashed; Modiolus australis, not seen; Odostomia sherriffi, apex of young shell, indeterminable; Pecten hutchinsoni not seen; Siphonalia valedicta indeterminable fragment; Trophon sp.? fragments of Turrid and another shell not generically located.

The Recent species Scalpomactra scalpellum. is doubtful. More specimens are required to show whether they are to be separated as a distinct species or not.

Genus Nucula Lamarck, 1799.
Type: Area nucleus Linné.

Nueula tersior n. sp. (Figs. 4, 6.)

Shell small, fragile, ovate; beaks prominent, about posterior sixth.Posterior end regularly convex; anterior end narrowly rounded, dorsal margin descending rapidly in moderate curve. Lunule not defined apart from increased curvature of disc. Escutcheon slightly bulging the outline, its outer margindefined by weak depression. Sculpture of low, bevelled, concentric ridges becoming obsolete over central part of disc which is smooth and shining; traces of fine radial threads appear in some of the interspaces. Hinge with about eleven anterior and five posterior teeth. Resilifer but little projecting. Valve-margins finely, regularly crenulated.

Holotype in collection of N.Z. Geological Survey.

Height, 2.5 mm.; length, 2.6 mm.

Suter identified this shell with N. hartvigiana Pfr. to which it is probably ancestral. The differences in the fossil, however, easily warrant specific recognition, e.g., much smaller size, more regularly rounded posterior end, fewer hinge teeth, broader beaks.

Nueula vestigial n. sp. (Figs. 1, 3.)

Shell small, ovate; beaks high, about posterior fourth. Lunule not well defined; escutcheon broad, bounded by low ridge. Sculpture of fine radial riblets, crossed by irregular, interlocking ridges in the spaces between which are the radials. Towards margin fairly regular, sharp, concentric ridges occur. Hinge strong, with about 11 anterior and 7 posterior teeth. Internal margin finely, regularly crenulated.

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Holotype in collection of N.Z. Geological Survey.

Height, 3.5 mm.; length, 3.5 mm.; inflation, 1.2 mm.

The irregular criss-cross sculpture resembles that of N. sagittata Suter on which it appears only on the lunule.

Genus Nuculana Link, 1807.
Type: Area rostrata Linné.

Nuculana probellula n. sp. (Figs. 2, 5.)

This shell is, in all probability, on the direct ancestral line of N. bellula (A. Adams) from which it differs in being less produced posteriorly. Further, the hinge is heavier and the escutcheon is more concave and has the concentric grooves reaching about half way across it. Young specimens are relatively more attenuated and approach but do not coincide with N. bellula. The hinge, however, is always rather longer and deeper. The sculpture of both species is of practically the same gauge, namely 6 or 7 grooves per mm. From N. belluloides Allan the Chatton shell is distinguished by the narrower posterior and more concave escutcheon.

Holotype in Dominion Museum.

Height, 4 mm.; length, 7 mm.; inflation (1 valve), 1.8 mm.

Genus cucullaea Lamarck, 1801.
Type: Cucullaea auriculdfera Lamk.

Cucullaea worthingtoni Hutton.

1873. Cucullaea worthingtoni Hutton, Cat. Tert. Moll., p. 27. 1873. Cucullaea attenuata Hutton, Cat. Tert. Moll., p. 28.

1914. Cucullaea worthingtoni Hutton: Suter, N.Z. Geol. Surv. Pal. Bull. 2, p. 37, pl. 6, Figs. 1, a, b,

1915. Cucullaea attenuata Hutton: Suter, N.Z. Geol. Surv. Pal. Bull. 3, p. 49, pl. 2, Figs. 1, a, b.

Young shells only, and so of uncertain specific position. They resemble Suter's figure (1915, p. 48, pl. 6, fig. 20) of Macrodon Cucullaria) australis Hutton, which Suter rightly classed as Cucullaea, but which he accepted as an adult, whereas in all probability it is a young shell of C. worthingtoni or a closely-related species. In any revision of New Zealand Tertiary species Cucullaea dalli colona v. Ihering (1907, p. 93) should not be overlooked. At present it is impossible to recognize this species as no locality and no figure were given by von Ihering.

Genus Glycymeris Da Costa, 1778.
Type: Area glycymeris Linné.

Glycymeris thomsoni n. sp. (Figs. 18, 21.)

Shell large and strong, oval, inflated. Anterior margin almost regularly convex, dorsal part slightly drawn up. Posterior margin subangled near middle by strong ridge running from umbo. Sculpture of about fifty low almost flat radial ribs with very narrow interspaces, ribs of posterior noticeably narrower, fairly wide space near both anterior and posterior dorsal margins free of these radials.

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Whole surface with traces of radial threads, five or six per rib. Ligamental area broad, about half length of shell, with five weak, fairly close, incised chevrons. Hinge-teeth, about four posterior and four anterior fully developed, rest invaded by ligamental area, and almost obliterated. Valve-margins crenulated.

Holotype in Dominion Museum.

Height, 81 mm.; length, 87 mm.; inflation (1 valve), 31 mm.

Easily distinguished from G. subglobosa by the shape.

Genus Limopsis Sassi, 1827.
Type: Area aurita Brocchi.

Limopsis parma n. sp. (Figs. 14, 15.)

Shell of moderate size, ovate; beaks not prominent. Outline somewhat variable. Up to about 15 cm. diameter, most are sub-circular; from then onwards some grow much more along posterioventral margin and so become markedly oblique, others keep more to the youthful outline though there is always a certain amount of obliquity. Some specimens show strong ventral growth and so become considerably elongated. Dorsal margins characteristically short and inclined. Surface with somewhat irregular, low, concentric ridges which are very weak on central part of disc, so shell has shining surface across which ridges cross as lines. Weak radial grooves are present, more strongly developed distally. Where they cross the concentric ridges, crenulations are formed which are fairly strong on posterior area. Cardinal area between one-half, and two-fifths length of shell, traversed by rather broadly triangular chondrophore which has apical angle of about 100°. Hinge broad, teeth relatively long, about 10 posterior and 10 anterior. Adductor impressions of moderate size, the anterior one not at all concealed by hinge plate. Valve-margins bevelled, smooth.

Holotype in Dominion Museum.

Height, 25 mm.; length, 26 mm.

This species is related to L. zitteli but distinguished from it by smaller chondrophore, more circular adult shell, and rather stronger ornamentation. It is close to L. campa Allan from Waihao green-sands, but has a smaller chrondrophore.

Genus Ostrea. Linné, 1758.
Type: Ostrea edulis Linné.
Subgenus Gigantostrea, Sacco, 1897.

Type: Ostrea gigantica Solander.

Ostrea (Gigantostrea) wollastoni Finlay. (Figs. 16, 17.)

1873. Ostrea incurva Hutton, Cat. Tert. Moll., p. 35 (not of Nilsson).

1915. Ostrea incurva Hutton: Suter N.Z. Geol. Surv. Pal. Bull. No. 3, p. 53, pl. 3, fig. 1, pl. 7, figs. 2a, b.

1927, Ostrea wollastoni Finlay, Trans. N.Z. Inst., vol. 57, p. 528.

A giant specimen was collected by Mr. Christie. It measures 165 mm. long and 183 mm. high. The depth of the left valve is

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110 mm., of this the body cavity occupies about 45 mm., so the shell substance is 65 mm. thick. The right valve is almost flat and has a maximum thickness of 49 mm. The total weight is 9 lbs. 7 ozs. The external surface is not well preserved, but radial ribs are absent. The outline is more circular than that of the type, and the ligamental area relatively larger.

Perhaps O. suteri v. Ihering (1907, p. 94) would be a better classification. This species was introduced only incidentally; but the locality, Westport, was given, and also characters to distinguish it from O. hatcheri Ortmann and O. patagonica d'Orb.

Genus Cyclopecten Verrill, 1897.
Type: Gyclopecten postulosus Verrill.

Cyclopecten compitum n. sp. (Fig. 8.)

Shell minute, prodissoconch smooth, sharply defined. Left valve with ears of moderate size not sharply defined from disc. Surface smooth in young stages, but later with many fine, close radial threads, not persistent but tending to zonal arrangement. Towards margin appear about 17 rounded, strong radial ribs with much wider interspaces. The ribs bear strong spaced scales and tend to be knotty. Concentric growth-lines well marked, some, especially on posterior, projecting as jagged edges.

Holotype in collection of N.Z. Geological Survey.

Height, 1.6 mm.; length, 1.4 mm.

Easily distinguished from the Recent species by the discrepancy in sculpture. In a recent revision of the New Zealand Pectinidae (Marwick, 1928, p. 456) the writer unfortunately overlooked a lapsus calami so that Cyclochlamys appears instead of Cyclopecten. Thanks are due to Dr. H. J. Finlay for noticing this mistake.

Genus Chattonia n. gen.
Type: Chattonia animula Marwick.

Shell small, hatchet-shaped, strong; beaks prominent, at anterior third or fourth; posterior end broadly truncated, bounded below by low ridge. Sculpture, of regular concentric grooves. Hinge of moderate width. Left hinge with two narrow, divergent, anterior cardinal teeth, anterior one much the stronger and well separated from raised lunular border. Behind these cardinals is a triangular ligamental space bounded posteriorly by long curved posterior lateral which extends two-thirds length of dorsal margin from which it is separated by a well-defined groove. Right hinge with long straight anterior lateral confluent with lunular margin above; cardinal tooth strong, posterior lateral long, curved. Internal margins smooth.

Chattonia animula n. sp. (Figs. 10, 11, 12.)

Holotype in Dominion Museum.

Height, 4.5 mm.; length, 5.3 mm.; inflation (1 valve), 1.25 mm. For description see generic diagnosis above. The specimens show considerable variation in shape, size, and coarseness of sculpture, so that further collecting may necessitate specific subdivision. The

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largest specimen is nearly 9 mm. long. The elements of the hinge are the same as those of Crassatellites, but this does not necessarily demand inclusion in that genus, for the crassatelloid hinge is an extremely conservative one. The small size, the curved dorsal margin, the shape of the lateral teeth, and the very narrow ligamental scar on the hinge deserve full generic recognition.

Genus Venericardia Lamarck, 1801.
Type: Venericardia imbricata Lamk.

Venericardia christiei n. sp. (Figs. 23, 28, 30.)

Shell large, heavy; beaks prominent, near anterior end. Lunule deeply sunk, convex in youth, but sloping inwards as growth proceeds, bounded by an incised line. Escutcheon shallow, not well defined. Sculpture of about 24 strong, rounded radial ribs, with well-marked interstices of about same width. Close, regular growth-striae cover the shell but are stronger in interstices, also ribs have indications of obscure nodes at intervals. In spite of these irregularities the surface has a smooth shining appearance. Hinge deep and strong, teeth well grooved; left valve with the inward sloping lunule only slightly invading anterior cardinal tooth with which it forms an angle of 30°. Right valve with a broad median cardinal well separated from thin anterior cardinal which in turn is distant from lunular margin; posterior cardinal forming rudimentary ridge on nymph.

Holotype in Dominion Museum.

Height, 50 mm.; length, 50 mm.; inflation (1 valve), 19 mm.

This species is related to V. awamoaensis Harris (= V. pseutes Suter) but it can readily be recognized by the higher, narrower ribs and wider interspaces. The hinge-teeth, and lunule of V. christiei are not so oblique as those of V. awamoaensis, so that the space between the lunular border and the anterior cardinal is much wider. Also V. awamoaensis is usually less oblique in shape, the umbos being lower and not so far forward.

Venericardia pseutella n. sp. (Figs. 29, 31.)

Shell of moderate size, beaks prominent, about anterior fifth. Lunule small, concave, sloping forward below, scarcely invading anterior cardinal tooth above. Escutcheon not developed. Sculpture of 28 very low, smooth, rounded radials with linear interstices, ribs of posterior area narrower than others. Left hinge with two strong cardinals, anterior one forming with lunule a triangular space; posterior one arched.

Holotype in Dominion Museum.

Height, 21.5 mm.; length, 22.5 mm.

Only two incomplete left valves were collected. They closely resemble V. awamoaensis Harris but differ in having the lunule sloping forward instead of backward, almost parallel to anterior cardinal, in this respect being like V. christiei. They are readily distinguished from this shell however by the much weaker and more numerous radials.

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Venericardia caelebs n. sp. (Figs. 22, 24.)

Shell of moderate size, umbo fairly prominent, at anterior fourth. Lunule convex, cordate, sloping forward. Escutcheon not developed. Sculpture of 29 high, rounded, radial ribs with interspaces about same width; anterior two ribs and posterior one extremely weak. Ribs on anterior part of disc with regular transverse ridges, but those on posterior part almost smooth, except the fourth from last which has prominent spaced spines. Ribs on posterior area considerably weaker than those of central part of disc. Hinge of moderate width; left valve with anterior cardinal strong, triangular, well separated from arched lunular border; posterior cardinal long, arched, of moderate strength, parallel to ligamental nymph. Right median cardinal evidently very broad.

Holotype in collection of N.Z. Geological Survey.

Height, 27 mm.; length, 30 mm.; inflation (1 valve), 10 mm.

Differs from the Recent species, V. difficilis (Desh.), in having rather more ribs, which, moreover, are almost smooth over a great part of the shell. The hinge is of the same general type as that of V. purpurata (Desh.) but the left posterior cardinal is longer and further away from the anterior one, so that the right median cardinal must be considerably broader. Also the adductor-scars of the Recent shells, especially the anterior one, are much larger than in the fossil. A single left valve has been collected.

Subgenus Pleuromeris Conrad, 1867.
Type: Cardita tridentata Say.

Venericardia (Pleuromeris) prolutea n. sp. (Figs. 25, 26, 27.)

Shell small, subequilateral; beaks almost central, moderately high. Linule flattened, large, lanceolate, smooth, not invading hinge-area. Escutcheon long and narrow, smooth, not depressed. Sculpture of sixteen high, strongly and regularly-beaded radial ribs with equal interstices. Left hinge with two strong cardinals forming angle of about 77°; anterior cardinal well separated from lunular margin. Anterior and posterior laterals present. Right hinge with strong triangular median cardinal; anterior and posterior cardinals rudimentary. Anterior and posterior laterals present.

Holotype in Dominion Museum.

Height, 6 mm.; length, 6 mm.; inflation, 2.25 mm.

Differs from the Recent V. lutea Hutt. in having more ribs, and in the beaks being almost median, thus making the shell subequilateral. Further, the hinge-line is narrower in the fossil.

Genus Eulopia Dall, 1901.
Type: Lucina sagrinata Dall.

Subgenus Notomyrtea Iredale, 1924.
Type: Myrtea botanica Hedley.

Eulopia (Notomyrtea) staminifera n. sp. (Figs. 35, 36, 37.)

Shell small, laterally compressed, beaks central, prominent. Lunule and escutcheon well defined, long, narrow, smooth, wider in

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left valve. Sculpture of rather sharp, concentric, irregularly-spaced lamellae, about five per millimetre, with wide, flat interspaces which are occupied by dense vermiculate radial threads. Left hinge with two curved triangular cardinals; margins of lunule and escutcheon raised distally to function as lateral teeth; lunular one with low ridge below, posterior one with trace of a groove. Right hinge with curved triangular cardinal and a strong anterior also a strong posterior lateral, each of which forms with raised margin a deep socket to receive lateral tooth of left valve. Adductor impressions not strongly marked but apparently triangular, anterior one slightly elongated.

Holotype in Dominion Museum.

Height, 5.6 mm.; length, 6.3 mm.; inflation (1 valve), 1.2 mm.

E. staminifera differs from E. papatikiensis in shape, the beaks being considerably higher, so that the angle between dorsal and lunular margins is less. Also the left anterior lateral of E. papatikiensis is well developed and distant from the lunular margin.

When Iredale (1924, p. 206) introduced Notomyrtea for Australian shells with fine radials in the concentric interspaces, he did not discuss Eulopia proposed by Dall. for American shells with the same feature. Recently Finlay (1926, p. 461) transferred Myrtea (Eulopia) papatikiensis Marwick to Notomyrtea, also without discussing Eulopia. The only outstanding difference from the New Zealand shells shown by E. sagrinata is the considerably greater inflation. The general shape, sculpture, and hinge are so alike that it would be well to associate the groups generically. The radial ornament is a very persistent character and marks clearly defined groups of extended range both geographically and stratigraphically; it therefore justifies generic recognition of Eulopia.

Genus Gonimyrtea n. gen.
Type: Loripes concinna Hutton.

Shell subtriangular because of obscure ridge running from umbo to middle of anterior margin, and another to posterior margin which is angled below middle. Lunule broadly concave, not invading hinge area, and not interfering with development of teeth. Lateral teeth of right valve extremely weak, left valve with no true laterals, the lunular margin being slightly raised to function as one. Anterior adductor impression long and narrow.

The poor development of lateral teeth, the long anterior adductor, and the shape of the shell, readily distinguish this genus from Notomyrtea.

Finlay (1926, p. 461) has already noted the possibility of this distinction.

Gonimyrtea bucculenta n. sp. (Figs. 32, 33, 34.)

Shell subcircular, beaks slightly in front of middle, not prominent. Lunule lanceolate, well sunk, smooth. Escutcheon absent. A weak ridge runs to anterior margin from umbo forming weak, anterior wing. Sculpture of narrow, relatively high, very regular concentric ridges, 6 per millimetre, with much wider flat interspaces. Left

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hinge with two small cardinals diverging from under umbo, lunular margin raised to function as a lateral. Right hinge with single triangular cardinal and small anterior tubercle. Anterior muscle-impression long and narrow, posterior triangular. Interior of shell striated above pallial line. Valve-margins smooth.

Holotype in collection of N.Z. Geological Survey.

Height, 6 mm.; length, 6.5 mm.; inflation (1 valve), 2 mm.

Distinguished from the Recent and Pliocene P. concinna by the more orbicular shape, less prominent anterior and posterior marginal angulations and well spaced ribbing.

Genus Maoritellina Finlay, 1926.
Type: Tellina charlottae E. A. Smith.

Maoritellina imbellica n. sp. (Figs. 7, 9.)

Shell small, fragile, ovate. Beaks slightly behind middle line. Anterior end rather narrowly convex, the dorsal margin slightly curved descending fairly rapidly. Posterior end subangled, bent slightly to right. Sculpture of low, sharp, concentric threads, distantly and regularly spaced, but developed only on posterior half of disc. A few microscopic radials closely grouped are on distal posterior part of obscure fold running from umbo to posterior angle. Right hinge with two cardinals, anterior narrow, posterior triangular, bifid, laterals well developed, posterior slightly closer to umbo than anterior but not overlapping ligament. Pallial sinus not visible. Valve-margins smooth.

Holotype in collection of N.Z. Geological Survey.

Height, 4.5 mm.; length, 6 mm.

Genus Dosinia Scopoli, 1777.

Type: Artemis africana Hanley.
Subgenus Raina Marwick, 1927.
Type: Dosinia bensoni Marwick.

Dosinia (Raina) sodalis n. sp. (Figs. 38, 39, 40.)

Shell of moderate size, strong, subcircular. Lunule long and narrow, bounded by deeply-incised line. Escutcheon long and deep, bounded by sharp ridge especially in left valve. Sculpture of high, narrow, erect, regular, well-spaced concentric ridges, about 8 per centimeter, becoming obliquely lamellar on posterior slightly concave area. Left hinge with strong curved posterior cardinal; strong rugose median, and lamellar anterior cardinal, space between last two with deep pit along anterior side. Anterior lateral broad, low, very strongly ridged. Right hinge with fairly strong, bifid, posterior cardinal, stout, rugose median, and short, thin and low anterior cardinal. Space between first two with shallow excavation along posterior side. Anterior pit with low smooth lateral above, strongly grooved below.

Holotype in Dominion Museum.

Height, 52 mm.; length, 52 mm.; inflation (1 valve), 14 mm.

Easily distinguished by the sculpture, concentrated hinge, and very deep escutcheon.

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Dosinia (Raina) imperiosa n. sp. (Figs. 41, 42.)

Shell large and heavy. Lunule large and broad, bounded by incised line. Escutcheon deep, not commencing until shell is about 20 mm. diameter, crossed by fairly strong continuations of the concentric sculpture. Sculpture of strong, bevelled, polished, concentric ridges with slightly narrower interspaces, the ridges becoming narrower and oblique on posterior area. Right hinge with strong, bifid posterior cardinal; strong, triangular, rugose median, and short, strong, high anterior cardinal. Anterior pit deep, with weak, smooth lateral above, strongly rugose below. Nymph with strongly raised anterior margin along groove for left posterior cardinal. Pallial sinus reaching to near middle of shell.

Holotype in Dominion Museum.

Height (estimated), 60 mm.; length (estimated), 60 mm.; inflation (1 valve), 20 mm.

Distinguished from D. sodalis by greater inflation and broader lunule, escutcheon starting at much later stage, broader right posterior and anterior cardinals, and sculpture.

Genus Pholadidea Goodall, 1819.
Type: Pholadidea loscombiana Goodall.

Pholadidea increnata n. sp. (Fig. 13.)

Shell somewhat small, elongate; beaks at anterior fourth. Anterior dorsal margin strongly reflexed. Sculpture: an oblique groove stretching from umbo backwards to middle of ventral margin. Behind this the surface bears low, broad, regular concentric folds with in addition one or two irregularly placed growth-lamellae. In front of the groove are strong, regular, well-spaced concentric lamellae which show only faint traces of marginal crenation. No sign of anterior lower callus-plates.

Holotype in Dominion Museum.

Height, 10 mm.; length, 18.5; inflation (1 valve), 4 mm.

Differs somewhat from the Recent P. tridens Gray in broader posterior and presence of well-spaced, scarcely crenate lamellae on the anterior area. Also the anterior ventral margin ascends, in a gentle convexity from the oblique groove and not in a broad sinus.

Genus Myadora Gray, 1840.
Type: Pandora brevis Sowerby.

Myadora delta n. sp. (Figs. 19, 20.)

Shell rather small, subtriangular; beaks slightly behind middle; apical angle about 100°. Left valve concave, with relatively strong posterior twist. Anterior dorsal margin straight, descending at about 45° to narrowly rounded anterior margin. Posterior dorsal margin flatly sigmoid, merging into obliquely truncated posterior margin. Ventral margin widely arcuate. Lunule and escutcheon narrow, flat, extending full length of dorsal margins. Sculpture of low, broad, concentric ridges, obsolete over most of disc, but strong along anterior dorsal margin. Lithodesma narrowly triangular. Anterior and posterior margins of shell raised and grooved along whole length. Adductor-scars noticeably distant from umbo and near ventral

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margin. Pallial sinus broad and shallow, a radial groove extending from front of it towards umbo. Valve-margins smoothly rounded.

Holotype in Dominion Museum.

Height, 7.5 mm.; length, 9.5 mm.

Paratype, 7.3 × 9 mm.

This shell resembles M. novaezelandiae Smith in shape but the apical angle is considerably greater.

Genus Antisolarium Finlay, 1926.
Type: Solarium egenum Gould.

Antisolarium vixincisum n. sp. (Fig. 44.)

Shell small, fragile, conical, perforate. Whorls six, moderately convex, increasing regularly; body-whorl angled at periphery in young but only subangled in adult; base convex. Protoconch conic, with small nucleus, number of whorls uncertain as no division between it and brephic stage is to be seen. Suture impressed. Sculpture of indistinct spiral ridges somewhat irregularly spaced, about 6 on body-whorl above periphery, which is marked by a fairly strong thread. Some species have only a spiral below the suture and one on periphery. On base, the spirals are extremely weak, but a moderately strong one is sometimes present close to periphery. Faint but regular growth-lines cross obliquely backwards from suture to periphery, and are noticeably arcuate between periphery and umbilicus. Umbilicus open, about ¼ diameter of base, bounded by strong, moniliform thread which has a smoother, weak spiral above and sometimes one below it. Aperture subrhombic. Outer lip retreating from suture at about 45°, broadly sinused on base. Inner lip broadly concave above where it sweeps round to parietal wall, sometimes lightly channelled below at ends of umbilical spirals.

Holotype in Dominion Museum.

Height, 4 mm.; diameter, 4 mm.

On several specimens traces of the colour-ornament of brown axial bars and splotches still remain.

No very closely-related species has yet been described, the absence at any stage of the biangulate spire-whorl being peculiar. Many of the specimens are quite smooth, but this may be the result of decortication, as the outer shell-layer is inclined to become powdery.

Genus Elachorbis Iredale, 1915.
Type: Cyclostrema tatei Angas.

Elachorbis duplicarina n. sp. (Figs. 43, 45, 46.)

Shell minute, almost planispiral. Whorls four, convex on spire, body-whorl bicarinate. Protoconch of 2¾ smooth whorls with first two showing but little increase in diameter. Sculpture of four smooth spiral cords on body-whorl above periphery. Interstices about equal to cords. Upper keel, marking periphery, high and sharp; lower keel not so strong but still well defined. Space between keels with 3 rather close spirals; base with about 7 spaced threads. Growth-lines extremely fine. Aperture subcircular, with blunt angles at the keels. Outer lip thin, oblique. Umbilicus wide, open, with a strong

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spiral which causes an embayment in the inner lip.

Holotype in collection of N.Z. Geological Survey.

Height, .8 mm.; diameter, 2 mm.

The classification under Elachorbis is only provisional, for the two strong keels are not present in that genus. The shell figured by Cossman [1918, pl. 2, figs. 51, 52, 53] as Tornus (Adeorbis) miobicarinatus Sacco, from the Miocene of Prance, has a strong resemblance in general characters.

Genus Spirocolpus Finlay, 1926.
Type: Turritella waihaoensis Marwick.

Spirocolpus tophina (Marwick).

1926. Turritella tophina Marwick, Trans. N.Z. Inst., vol. 56, p. 313, pl. 72, fig. 21.

The adult specimens available are all somewhat eroded, but they seem to agree closely with the Waiarekan species. Many well-preserved apices occur, showing the strongly monilform character of the spirals on early whorls.

Genus Zeacolpus Finlay, 1926.
Type: Turritella carlottae Hutton.

Zeacolpus chattonensis n. sp. (Figs. 47, 49.)

Shell of moderate size, apical angle about 20°. Protoconch of about two smooth whorls. Sculpture commences with two smooth spirals on first post embryonic whorl, upper spiral stronger and giving whorl strong angulation, on second whorl a weak thread appears above first two; for first three post-embryonic whorls or so, upper of the two primary spirals is stronger, but about fourth whorl the lower equals it and on fifth forms prominent keel and upper primary degenerates to fine thread. Meanwhile, fine spiral threads have been appearing from about second whorl, so whole surface is closely spiralled. Strongly-keeled condition holds for three or four whorls during which upper part of each whorl has gradually been rising above suture, forming a cingulum with two strong threads and several weak ones. One of these strong threads is probably continuation of that commencing on second whorl. The whorls which are now about 4 mm. diameter retain much the same character until about 12 mm. diameter; that is, the whorl is girdled by median concavity bounded below by single strong spiral, concave under-side of which retreats rapidly to constricted suture. Upper side of median concavity bounded by weaker spiral with another still weaker on each side, the three set on a cingulum of the whorl which retreats to suture in a convexity. Whole surface with fine spiral threads, some of which become relatively prominent. The specimen shown in figure 47 appears to be a gerontic development, the whorl is almost flat, but the suture is still well constricted. Aperture subquadrate, outer lip with a fairly deep sinus, the broadly rounded apex of which is slightly below mid whorl and posterior side advancing further than anterior.

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Holotype in Dominion Museum.

Height (estimated), 45 mm.; diameter, 12 mm.

Paratype (Fig. 47), estimated 80 × 20 mm.

Genus Zefallacia Finlay, 1926.
Type: Fastigiella australis Suter.

Zefallacia chattonensis n. sp. (Fig. 63.)

Shell large, turriculate, increasing regularly. Whorls cylindrical, suture deeply incised, body-whorl contracted quickly to short twisted canal not notched at base. Sculpture of low, regular, arcuate growth-ridges. Body-whorl with a few weak spirals just below suture-line. Aperture ovate, produced below into twisted canal about half length of aperture. Outer lip retreating from suture in broad shallow sinus. Columella with strong fold which is sharp and median in youth, but rounded and more anterior at maturity. Inner lip of adult with broadly expanded, projecting callus-plate.

Holotype in Dominion Museum.

Height (estimated), 70 mm.; diameter, 20 mm.

As noted by Finlay (1926, p. 384) this is the shell identified by Suter (1921, p. 95) as the Mesozoic Nerinea Defrance. Although the New Zealand shell certainly resembles Nerinea it does not belong to that family but to the Cerithiidae as placed by Finlay. This is shown by the single fold on the columella, complete absence of folds on the outer lip or parietal wall, and by the twisted canal. From Z. australis (Suter) the new species differs in being very much larger and in having regularly-increasing whorls. Whether adult Z. australis has an expanded inner lip is not known.

Genus Pyrazus Montfort, 1810.
Type: Strombus palustris Linné.

Pyrazus sutherlandi n. sp. (Fig. 48.)

Shell large, solid, outline almost straight. Whorls, about 12 remaining, with shoulder slightly indicated by axials. Suture impressed, undulating. Sculpture of about eleven axial ribs per whorl. Ribs are broadly rounded and slightly nodulous being weaker across shoulder but extend from suture to suture and die out on base. Interspaces slightly wider than ribs. Whole surface with fine spiral threads, showing best in interstices. Last quarter whorl has been repaired after a break, and on it spirals are much stronger; six, especially, develop into rugose cords more prominent on ribs than in interspaces. Outer lip broken away. Columella twisted, apparently produced along short canal. Inner lip with fairly thick callus adhering to base of shell.

Holotype in collection of N.Z. Geological Survey.

Height, 100 mm.; diameter, 35 mm.

As the aperture is incomplete it is impossible to be sure about the generic affinities of this shell. Nothing closely related to it has so far been described from New Zealand; but judging from the figure Cerithium pritchardi Harris (1897, p. 226, pl. 7, fig. 3) belongs to the same group. Harris remarked on the resemblance of his species to C. semicostatum Deshayes (European Eocene) which is a Vulgocerithium Cossmann.

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Genus Maoricrypta Finlay, 1926.
Type: Crepidula costata Sowerby.

Maoricrypta salebrosa n. sp. (Figs. 50, 51.)

Shell of moderate size, strongly convex, relatively high and narrow. Beaks strongly incurved, twisted well to the side and separated from the apertural margin by wide space covered with growth-lines. Sculpture of about 12 to 16 rounded, irregular, gnarled, spiral ridges with equal or wider interstices. These ridges generally stronger along crest of shell and narrower on outer or left side than on inner or right side. Growth-lines irregular. Septum extending about halfway along shell, a little further on left than right; anterior margin gently concave, with very shallow sinus in middle.

Holotype in Dominion Museum.

Height, 17 mm.; length, 40 mm.; width, 23 mm.

The sinuosity of the septal margin is rather better marked in this species than in the others of the group, i.e., M. costata Sowerby, M. wilckensi Finlay, etc., and is very different from that of the type of Crepidula, C. fornicata L. In Crepidula the septal margin follows a shallow sigmoid curve, in Maoricrypta it is gently concave with a shallow median sinus.

Genus Sigapatella Lesson, 1830.
Type: Calyptraea (Sigapatella) novae-zelandiae Lesson.

Sigapatella mapalia n. sp. (Figs. 58, 59.)

Shell somewhat small, spire excentric. Protoconch of about two smooth whorls, conspicuously tilted and with nucleus slightly involved by second whorl. Post embryonic whorls two, strongly convex except for about one quarter turn of brephic stage where the whorl is much less convex. Sculpture, inconspicuous; concentric growth-lines fairly well marked on some specimens, a few with numerous weak spiral cords with interspaces of same width. Suture well defined on later part because of convexity of whorls, but obscure on early part. Basal plate with obliquely penetrating umbilicus.

Holotype in Dominion Museum.

Height, 5 mm.; diameter, 8 mm.

Resembles S. novae-zelandiae in general apearance and in the presence of a penetrating umbilicus; but differs in having a projecting, tilted protoconch and early whorls much like those of S. terrae-novae; also the margin of the basal plate is not bent forward so strongly where it bounds the umbilicus.

Genus Polinices Montfort, 1810.
Type: Natica brunnea Link (= N. mammilaris Lamk.)

In a revision of the Naticidae of New Zealand, the writer (Marwick 1924) used the genus Uber of Humphries having overlooked Opinion 51 of the International Commission on Zoological Nomenclature. This was kindly pointed out in a letter by Dr. W. P. Woodring.

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Polinices blaesus n. sp. (Fig. 62.)

Shell of moderate size, spire relatively high; body-whorl compressed for some distance below suture for last half whorl. Suture ill defined. Surface smooth. Aperture semilunar. Outer lip joining suture at about 85° but curving round to retreat rapidly in a broad curve. Apertural callus moderate, with canal at posterior end along inside of projecting outer lip, and broad depression about middle subdivided by wide faint ridge; outer edge of callus opposite transverse depression drawn up in thin layer to obtuse angle on parietal bulge of whorl. Umbilicus restricted to merest penetrating chink.

Holotype in Dominion Museum.

Height, 32 mm.; diameter, 24 mm.

Closely related to P. obstructus (Marw.) but differing in poor development of transverse grooves of callus. Also the mass of the callus does not extend so far out of the aperture. The compression of the body-whorl below the suture if constant should provide ready means of identification.

Polinices lobatus (Marwick).

1924. Uber lobatus Marwick, Trans. N.Z. Inst., vol. 55, p. 562, pl. 58, fig. 2.

The single specimen is a gerontic individual with a contracted outer lip. The apertural callus is not so well grooved and is narrower than the typical P. lobatus, but more specimens are required to show how constant these differences are.

Genus Odostomia Fleming, 1817.
Type: Turbo plicatus Montagu.

Odostomia alexanderi n. sp. (Fig. 60.)

Shell relatively large, only two last whorls remaining. Penultimate whorl but slightly convex, body-whorl elongate oval. Surface smooth, shining, with fairly strong growth-lines. Suture impressed. Columella with single strong fold.

Height (estimated), 10 mm.; diameter, 3 mm.

Easily distinguished from O. georgiana Hutton by the elongately-oval body-whorl. Although the specimen is incomplete it should be readily identifiable, and so has been given a name.

Genus Syrnola A. Adams, 1860.
Type: Syrnola gracillima A. Adams.

Syrnola wallacei n. sp. (Fig. 54.)

Shell small, elongate, conic; spire about 4 times height of aperture. Whorls nine, flat to slightly convex on spire, body-whorl rounded at periphery, base slightly convex, sloping inwards at about 45°. Protoconch heterostrophic, paucispiral, with large nucleus. Suture channelled. Surface smooth and shining with merest suggestion of axial ribs; body-whorl with one or two very weak spiral threads on line of suture which is below periphery. Aperture oval. Outer lip sinuous, convex below. Columella with strong sharp fold high up.

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Holotype in collection of N.Z. Geological Survey.

Height, 4.75 mm.; diameter, 1.4 mm.

Differs from S. semiconcava Marsh, and Murd. and S. menda Finlay in more convex outline of whorl and deeper suture, and from S. lurida Suter and S. tenuiplicata Murd. and Sut. in much shorter body-whorl and stronger columellar fold.

Syrnola aclyformis n. sp. (Fig. 55.)

Shell small, elongate, conic; spire four times height of aperture. Whorls nine, flat, increasing very gradually; body-whorl broadly rounded at periphery. Protoconch heterostrophic, narrow and high. Suture scarcely indenting outline. Surface smooth, shining, with faint growth-lines sloping obliquely forward. Aperture incomplete in the single specimen; but columella with strong fold.

Height, 5.1 mm.; diameter, 1.4 mm.

Distinguished from other described species in New Zealand by the shallow suture, and consequent straight outline.

Genus Turbonilla Risso, 1826.

Type: Turbonilla typica Dall & Bartsch.
Subgenus Strioturbonilla Sacco, 1892.
Type: Turbonilla sigmoidea Jeffreys.

Turbonilla (Strioturbonilla) chattonensis n. sp. (Figs. 52, 53, 57, 61.)

Shell elongate, conic. Protoconch heterostrophic, of two and a half smooth helicoid whorls with rather small nucleus. Post-embryonic whorls eleven in holotype but probably reaching 14 in others, much broader than high, outlines lightly convex; body-whorl rounded at periphery. Suture strongly constricted. Sculpture, holotype with 16 (paratypes up to 22) oblique, slightly curved ribs with somewhat narrower, excavated interspaces which extend from higher suture to lower but here stop abruptly thus terminating the ribbing. Very fine spiral grooves occupy the rib interspaces, about 24 on the body-whorl of large specimen; base also covered with fine spirals, the interspaces slightly wider towards periphery. Aperture subquadrate, columella with fold placed high up.

Holotype in Dominion Museum.

Height, 6.75 mm.; diameter, 1.8 mm.

Paratype, height (estimated) 10 mm.; diameter, 2.4 mm.

In shape T. chattonensis resembles T. powelli Bucknill, but the whorls are relatively much lower. T. suteri Powell has more convex whorls. Neither of these species has the fine spiral lirae. T. awamoaensis Marsh. & Murd. has strong spiral sculpture and a different outline.

Genus Proximitra Finlay, 1926.
Type: Vexillum rutidolomum Suter.

Proximitra incisula n. sp. (Fig. 67.)

Shell somewhat small, fusiform, spire slightly shorter than aperture. Whorls seven including protoconch which consists of about

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2 smooth whorls of tectiform shape with large nucleus. Sculpture of 14 or 15 weak axial ribs, about their own width apart on spire but more distant on body-whorl. These are crossed by numerous close spiral threads, well marked on shoulder but becoming obsolete on sides of whorls. Aperture elongate, not notched below; outer lip slightly sinuous. Columella with four distant folds, anterior one weak, others strong.

Height, 12.5 mm.; diameter, 6 mm.

Holotype in collection of N.Z. Geological Survey.

P. incisula is easily distinguished from others of the genus by its small size, rather plump outline and spiral sculpture of close threads well marked only on the shoulder.

Genus Xymenella Finlay, 1926.
Type: Trophon pusillus Suter.

Xymenella inambitiosa n. sp. (Figs. 65, 68.)

Shell small, broadly fusiform. Protoconch convex of three smooth whorls with a small tilted nucleus, two rudimentary axials near termination which is varixed. Post-embryonic whorls three, convex; body-whorl convex, obscurely shouldered by spiral ornamentation, retreating rapidly below to somewhat short, slightly twisted neck which bears a low ridge but no fasciole. Sculpture: spire-whorls with two strong distant spiral cords; body-whorl with about 9, the lower 5 crowded together on base and neck. These are crossed by strong, sharp axials about 14 per whorl giving whole surface regularly cancellate appearance. Aperture oval, produced into slightly-twisted canal which is not anteriorly notched. Outer lip strongly varixed, bearing on inner side about 5 teeth which decrease in strength anteriorly. Columella smooth, twisted below to the canal.

Holotype in Dominion Museum.

Height, 5 mm.; diameter, 3 mm.

Characterized by the sharp axials and small number of spirals. The axials are really sharp varices, and on some specimens they are strongly developed at one or more places on the body-whorl showing where a complete aperture had been formed and then superseded by further growth.

Genus Baryspira Fischer, 1883.
Type: Ancillaria australis Sowerhy.

Baryspira electa n. sp. (Fig. 73.)

Shell somewhat small, subcylindrical; spire about equal in height to aperture. Callus of spire with weak spirals. Callus of inner lip extending upwards to apex of spire, its outer margin in a shallow sigmoid curve. The lower part of the columella bears six about equal spiral folds, the top one somewhat stronger. The interspace below it bears a weak thread.

Holotype in Dominion Museum.

Height, 22 mm.; diameter, 8 mm.

Closely related to B. hebera (Hutton) but differing in the disposition of the apertural and spiral callus; the sinuous outer margin

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on the spire being gently convex, whereas in B. hebera it is concave. The folds on the columella are more uniform in size and not grooved down the middle as in B. hebera. There are also differences in the spiral grooves of the anterior part of the shell. The same characters serve to distinguish this species from B. subhebera, Marwick, which has much more callus on the spire.

Genus Erato Risso, 1826.
Type: Cypraea cypraeola Brocchi.

Erato marshalli n. sp. (Fig. 56.)

Shell minute, ovate, spire low. Protoconch slightly tilted of about 1½ smooth planorbid whorls. Post embryonic whorls two and a half; body-whorl convex, inflated near posterior end of outer lip, contracted below. Suture not covered. Surface smooth and shining. Aperture elongate, expanded posteriorly, lightly sinused anteriorly. Outer lip convex, thickened, bordered, with 10 fine denticules internally. Inner lip also with about 10 denticles, the lower ones elongated into small folds, the upper ones merging into a keel.

Holotype in Dominion Museum.

Height, 2.7 mm.; diameter, 1.9 mm.

Differs widely in shape from the other Tertiary species.

Genus Austrodrillia Hedley, 1918.
Type: Pleurotoma angasi Crosse.

Austrodrillia cinctuta n. sp. (Fig. 74.)

Shell small, fusiform; spire gradate, about one and a half times height of aperture. Protoconch of about 1½ smooth inflated whorls. Post-embryonic whorls six; body-whorl retreating in shallow convexity to short, slightly twisted neck which is swollen but without fasciole. Sculpture of about 10 or 11 axials, bluntly tuberculate on shoulder angle but very weak on base and on shoulder, though still visible in sub-sutural band. Whole surface with close spiral threads; shoulder with four, and three on sub-sutural band; spire-whorls with four, body-whorl with about 24 below periphery, those on base stronger and more spaced. Suture borderd below by well marked, weakly moniliform band. Aperture elongate, produced below into short wide canal not sinused anteriorly. Outer lip with broad, rather shallow sinus between suture and periphery. Columella with suggestion of fold caused by swollen neck. Inner lip smooth, bordered on neck by shallow depression.

Holotype in Dominion Museum.

Height, 8 mm.; diameter, 3.5 mm.

Genus Austrotoma Finlay, 1924.
Type: Bathytoma excavata Suter.

Austrotoma inaequabilis n. sp. (Fig. 71.)

Shell of moderate size, strong; spire equal in height to aperture. Post-embryonic whorls about six, angled above middle, with concave shoulder and vertical sides. Body-whorl contracting slowly to straight

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neck which bears strongly-developed fasciole with rounded median ridge marking inner side of the narrow anterior notch. Sculpture: body-whorl with two strong, spaced spiral cords on periphery; above, on the concave shoulder, are fine spiral threads, and below, another strong spiral starts from about line of suture; it is the top one of about 14 between there and fasciole. Of these the upper five are stronger than the lower ones. Space between peripheral and sutural spirals with three sharp spirals of secondary strength, upper two fairly close together, and with single fine thread between them; between lower two, are three similar threads and a single one between lowest and sutural spiral. Interspaces of strong spirals on base and neck also with spiral thread. Sides of body-whorl with obsolete axial ribs. All interspaces crossed and fine spiral threads reticulated by regular growth-lines. Spire-whorls with moderately strong axial ribs about 16 per whorl, crossed by two spaced spirals at angle of shoulder, and with six weaker spirals on sides, the alternate ones being of secondary strength. Suture appressed. Aperture with a deep, narrow anterior notch. Outer lip with widely concave sinus on shoulder then sweeping forward in wide convexity opposite side and base. Columella smooth, gently bent to canal. Inner lip definitely limited, excavated, not quite obliterating two folds formed by edges of apertural notch.

Holotype in collection of N.Z. Geological Survey.

Height (estimated), 35 mm.; diameter, 13 mm.

The sculpture somewhat resembles that of A. excavata Suter, but the shape is very different.

Austrotoma toreuma n. sp. (Fig. 72.)

Shell of moderate size; spire slightly higher than aperture. Post-embryonic whorls about 6, angled above middle, with strongly concave shoulder and vertical sides. Body contracting relatively quickly to short almost straight neck which bears well marked fasciole strongly ridged down the middle. Sculpture, about 25 forward-sloping axial ribs per whorl, commencing at shoulder angle and dying out on base. Spire-whorls with six strong, spaced spiral cords, interspace of 3rd and 4th on penultimate whorl with a single spiral thread. Shoulder with five spaced spiral threads the outer one stronger than rest. Body-whorl with 16 strong, spaced spiral cords, top three a little closer and inclined to be nodulous where crossing axials; on shoulder, are now six threads, outer one almost as strong as the ones on sides and base. The single interstitial thread of penultimate whorl continues on to body and interspace below it also develops one, but the other interspaces do not. Shoulder and interspaces crossed by very strong regular growth-lines. Suture appressed. Aperture oblong, with deep, narrow, anterior notch. Outer lip with wide, concave sinus on shoulder; convex below. Columella smooth, gently bent to canal. Inner lip definitely limited, excavated, not quite obliterating traces of the fasciole.

Holotype in collection of N.Z. Geological Survey.

Height, 30 mm.; diameter, 12 mm.

Easily distinguished from A. inaequabilis by the very strong sculpture, and general absence of interstitial spirals, and from A.

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scopalveus Fin. by the relatively higher spire, more slender shape and persistence of axial ribbing on the body. In the last respect it resembles A. robusta (Hutton) but differs from that species in shape.

Genus Phenatoma Finlay, 1924.

Type: Pleurotoma novaezelandiae Reeve.
Subgenus Cryptomella Finlay, 1924.
Type: Leucosyrinx transenna Suter.

Phenatoma (Cryptomella) crassispiralis n, sp. (Fig. 75.)

Shell small, narrowly fusiform; spire higher than aperture. Protoconch conic, of 4 or 5 whorls, the last quarter angled and bearing some broad axial ribs. Post embryonic whorls four and a quarter; body-whorl contracting gradually to neck which has no fasciole but is noticeably swollen. Sculpture: angle of shoulder with strong, smooth cord; steeply inclined, slightly concave shoulder bears two weaker spirals, between these and between top one and suture is fine spiral thread. On spire-whorls below shoulder-angle there is one fine cord, but body has seven of these on side and base, some interspaces with fine thread beginning on last half whorl. Neck with five spiral cords weaker than basal ones. Whole shell with strong, regular, spaced growth-ridges in interspaces and on some of the spirals. Aperture elongate, produced below into wide, slightly twisted canal which is lightly sinused anteriorly. Outer lip with narrow fairly deep sinus just above shoulder-angle, apex of sinus marked by lower shoulder-cord. Columella with broad strong fold corresponding to the swelling on neck and sinus of anterior canal. Inner lip smooth, definitely limited, excavated.

Holotype in Dominion Museum.

Height, 6 mm.; diameter, 2.5 mm.

Easily distinguished from P. transenna Suter and P. antecostata Suter by the strong basal spirals.

Genus Acuminia Dall, 1908.
Type: Terebra lanceata Linné.

Acuminia transitorsa n. sp. (Fig. 69.)

Shell of moderate size, acuminate, turriculate. Spire 3½ times height of aperture. Whorls cylindrical, bulging noticeably just below the suture, body-whorl with base quickly contracting to short, slightly twisted neck bearing well marked fasciole which is sharply limited exteriorly by narrow ridge. Protoconch not preserved in available specimens but probably polygyrate with small nucleus. Sculpture of about 22 low, narrow, flexuous axials with wide flat interspaces. Aperture rhomboid, produced below into deeply-notched canal. Outer lip with broad shallow sinus above and another on base. Columella smooth, twisted to canal but with no other fold.

Holotype in collection of N.Z. Geological Survey.

Height, about 42 mm.; diameter, 8.5 mm.

This shell is readily distinguished from the common one at Target Gully by the more-transverse coiling of the whorls owing to

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their greater comparative width. Also the well-developed bulge below the suture gives a more-strongly gradate outline. Suter always identified the Target Gully shell as his T. orycta, but the type of that species is too poorly preserved for diagnosis. Topotypes should be collected and compared with the Target Gully specimens.

Acuminia suteri n. sp. (Fig. 70.)

Shell elongate, conic; spire about twice height of aperture. Proto-conch polygyrate, subconic, with small nucleus. Post-embryonic whorls seven, almost flat on spire. Body-whorl angled at periphery which is followed by suture. Base convex, contracting quickly to short twisted neck which bears strongly marked fasciole bounded exteriorly by a ridge. Sculpture: each later whorl with 14 strong, narrow axial ribs with wide concave interspaces. The ribs are slightly higher at both ends and stop suddenly just below the periphery. Whole surface with numerous, close, waved lirae. Aperture subquadrangular, produced below into short twisted canal with deep anterior notch. Columella smooth, twisted below to form the canal. Inner lip smooth, obliterating sculpture of base and fasciole apparently by solution.

Holotype in collection of N.Z. Geological Survey.

Height, 13.5 mm.; diameter, 5 mm.

Distinguished by the broad apical angle, angled periphery and quickly-contracting base.

Genus Acteon Montfort, 1810.
Type: Voluta tornatilis Linné.

Acteon chattonensis n. sp. (Fig. 66.)

Shell somewhat small. Protoconch low, nucleus tilted inwards. Post-embryonic whorls about 3½. Suture plainly marked, inclined to become channelled on weathering. Sculpture: spire-whorls smooth, last with spiral line bordering suture; body-whorl with two incised spiral lines below suture then smooth over curve of shoulder. Between line of suture and anterior end of body are about 17 incised, spaced spirals, upper four or five distant and having a weaker spiral in each interspace, lowest ones close together, the interspaces being like threads. Faint regular growth-lines cover whole shining surface and are stronger in the spiral grooves. Columella with a single strong fold.

Holotype in collection of N.Z. Geological Survey.

Height, 4.2 mm.; diameter, 2.75 mm.

Genus Ringicula Deshayes, 1838.
Type: Auricula ringens Lamarck.

Ringicula castigata n. sp. (Fig. 64.)

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

Shell minute, ovate; spire about 2/3 height of aperture. Whorls about four, convex. Protoconch smooth, paucispiral, with slightly-tilted nucleus. Sculpture of distant incised lines beginning about end of second whorl, but weak on spire. Penultimate whorl with 6 spirals

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on the side, a smooth band, caused by the omission of a spiral on curve of shoulder, above this a spiral groove forms a border below suture. Body-whorl with two grooves close below suture, then smooth space, then about 16 or 18 grooves, top 5 of which are further spaced than others. Outer lip much thickened and reflexed, curving forward below. Columella with two strong folds. Inner lip forming another calloused fold on the parietal wall.

Holotype in collection of N.Z. Geological Survey.

Height, 1.5 mm.; diameter, 1.1 mm.

The smooth band is not always present, for on some specimens the spirals are continuous.

References.

Cossmann, M., 1918. Essais de Paléoconchologie Comparée, vol. 11.

Finlay, H. J., 1926. A Further Commentary on N.Z. Molluscan Systematics. Trans. N.Z. Inst., vol 57.

Finlay and McDowall, 1924. Preliminary Note on the Clifden Beds. Trans. N.Z. Inst., vol. 55.

Harris, G. F., 1897. Catalogue of Tertiary Mollusca, British Museum, Pt. 1 (Australasia).

Ihering, H. von, 1907. Lea mollusques Fossiles du Tertiaire et du Crétacé Supérieur de l'Argentine. Anales del Museo Nacional de Buenos Aires, Ser. 3, tome 7.

Iredale, T., 1924. Results from Roy Bell's Collections. Proc. Linn. Soc. N.S.W., vol. 49, pt. 3.

Marshall, P., 1917. (a) The Wangaloa Beds, (b) Fossils and Age of the Hampden Beds. Trans. N.Z. Inst., vol. 49.

Marwick, J., 1924. Tertiary and Recent Naticidae and Naricidae of New Zealand. Trans. N.Z. Inst., vol. 55.

—– 1928. Tertiary Mollusca of Chatham Islands. Trans. N.Z. Inst. vol. 58.

Suter, H., 1915. Revision of the Tertiary Mollusca of New Zealand. N.Z. Geological Survey Pal. Bulletin, No. 3.

Suter, H., 1921. Lists of N.Z. Tertiary Mollusca. N.Z. Geological Survey Pal. Bulletin, No. 8.

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Figs. 1, 3.—Nucula vestigia n. sp., holotype × 7. p. 906.
Figs. 2, 5.—Nuculana probellula n. sp., holotype × 4.5, p. 907.
Figs. 4, 6.—Nucula tersior n. sp., holotype × 10. p. 906.
Figs. 7, 9.—Maoritellina imbellica n. sp., holotype × 6, p. 913.
Fig. 8.—Cyclopecten compitum n.sp., holotype × 20, p. 909.
Figs. 10, 11, 12.—Chattonia animula n. gen. n. sp., holotype and paratype × 6, p. 909.
Fig. 13.—Pholadidea increnata n. sp., holotype × 2, p. 914.
Figs. 14, 15.—Limopsis parma n. sp., holotype × 1.5, p. 908.

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Figs. 16, 17.—Ostrea (Gigantostrea) wollastoni Finlay. × .6, p. 908.

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Figs. 18, 21.—Glycymeris thomsoni n. sp., holotype × 1, p. 907.
Figs. 19, 20.—Myadora delta n. sp., holotype × 3, p. 914.

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Figs. 22, 24.—Venericardia caelebs n. sp., holotype × 1.2, p. 911.
Figs. 25, 26, 27.—Venericardia (Pleuromeris) prolutea n. sp., holotype and paratype × 5.5, p. 911.
Figs. 23, 28, 30.—Venericardia christiei n. sp., holotype and paratype × 1.2, p. 910.
Figs. 29, 31.—Venericardia pseutella n. sp., holotype × 3.3, p. 910.

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Figs. 32, 33, 34.—Gonimyrtea bucculenta n. sp., holotype × 4.3, p. 912.
Figs. 35, 36, 37.—Eulopia (Notomyrtea) staminifera n. sp., holotype and paratype × 5.4, p. 911.
Figs. 38, 39, 40.—Dosinia (Raina) sodalis n. sp., holotype × 1, p. 913.
Figs. 41, 42.—Dosinia (Raina) imperiosus n. sp., holotype × 1, p. 914.

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Figs. 43, 45, 46.—Elachorbis duplicarina n. sp., holotype × 13, p. 915.
Fig. 44.—Antisolarium vixincisum n. sp., holotype × 9.5, p. 915.
Figs. 47, 49.—Zeacolpus chattonensis n. sp., paratype × 1.2, holotype × 2.4, p. 916.
Fig. 48.—Pyrazus sutherlandi n. sp., holotype × 1-2, p. 917.
Figs. 50, 51.—Maoricrypta salebrosa n. sp., holotype × 1.2, p. 918.

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Figs. 52, 53, 57, 61.—Turbonilla (Strioturbonilla) chattonensis n. sp., holotype and paratype × 10, p. 920.
Fig. 54.—Syrnola wallacei n. sp., holotype × 10, p. 919.
Fig. 55.—Syrnola aclyformis n. sp., holotype × 10, p. 920.
Fig. 56.—Erato marshalli n. sp., holotype × 12, p. 922.
Figs. 58, 59.—Sigapatella mapalia n. sp., holotype × 5, p. 918.
Fig. 60.—Odostomia alexanderi n. sp., holotype × 7, p. 919.
Fig. 62.—Polinices blaesus n. sp. holotype × 1.2, p. 919.
Fig. 63.—Zefallacia chattonensis n. sp., holotype × 1.2, p. 917.

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Fig. 64.—Ringicula castigata n. sp., holotype × 20, p. 925.
Figs. 65, 68.—Xymenella inambig n. sp.,holotype × 7, p. 921.
Fig.66.—Acteon chattonesis n. sp., holotype × 8, p. 925.
Fig.67.—Proximitra incisula n. sp., holotype × 3, p. 920.
Fig.69.—Acuminia transitorsa n sp, holotype × 2, p. 924.
Fig.70.—Acuminia sutern n. sp., holotype × 3.7, p. 925.
Fig.71.—Acustrotoma inaequabilis n. sp., holotype × 1.8 p. 922.
Fig.72.—Austrotoma toreuma n. sp. holotype × 1.8 p. 921.
Fig.73.—Baryspira electa n. sp., holotype × 1.8, p.921.
Fig.74.—Austrodrtillia cinctuta n. sp., holotype × 6, p. 922.
Fig.75.—Phenatoma (cryptomella)crassispiralis n. sp., holotype × 6., p. 924.

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J. Allan Thomson
Born 1881—died 1928