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Volume 38, 1905
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Art. XVI.—Results of Dredging on the Continental Shelf of New Zealand.

[Read before the Wellington Philosophical Society, 7th June, 1905.]

Plates I and II.

Introduction.

During the meeting in January, 1904, of the Australasian Association for the Advancement of Science, at Dunedin, a party of the assembled zoologists proposed to attempt some deep-sea dredging. The project received the cordial sympathy of the President, Professor T.W.E. David, F.R.S., who referred to it in his presidential address.

To Professor Benham, Messrs. A. Hamilton, G. M. Thomson, and the writer, the use of a steamer was generously granted by the Dunedin Harbour Board. We gratefully acknowledge also the assistance of the Union Steamship Company of New Zealand, who provided us with deep-sea sounding apparatus, and the services of two of their officers to operate it.

I had brought with me from Sydney several hundred fathoms of wire rope and a dredging-bucket of my own design which had done good service on similar occasions. The latter may be briefly described as a conical bucket, the aperture of which was choked by a movable inverted truncated metal cone, like that fitted to the mouth of a rain-gauge.

The day appointed for the excursion was unfortunately spoilt by rough weather. We spent twelve hours of the 14th January in great discomfort, sounding and dredging about twelve to twenty miles outside Port Chalmers, in from 100 to 300 fathoms. As a result we lost considerable gear, and obtained only a cupful of bottom from 100 fathoms. The bucket dredge appeared to fill properly, and was raised to within a few fathoms of the surface when the line parted. It seemed to be twisted off. This accident I attribute to the want of a swivel link.

A second expedition was later organized in Auckland, where Professor Park, Rev. W. H. Webster, Messrs. H. Suter, R. Murdoch, and C. Cooper joined the writer. The bucket lost off Port Chalmers was replaced by one built by a local tradesman. A serviceable vessel, the “Awarua,” fitted with steam winding-gear, was engaged for the trip.

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On passing out to the open sea from the Hauraki Gulf we encountered a heavy swell, and found that the gale which had proved so disastrous to the Dunedin excursion had followed us up the coast. The success ultimately achieved was largely due to a happy suggestion of Mr. Cooper. By his advice we packed a sack with cotton-waste and poured therein a couple of bottles of machine-oil. Trailing this over the ship's side as we drifted, a zone of calm water afforded us protection while we dredged.

The spot selected for operations was in the vicinity of Cuvier Island, east of Great Barrier Island, in S. lat. 36° 8′, E. long. 175° 55′; depth, 110 fathoms. The time, sunrise on the 22nd January, 1904.

At or about the 100-fathom zone the submarine slope here, as elsewhere in New Zealand or East Austraili, suddenly changes to a steeper descent. I have met with no explanation of this phenomenon, and now venture to suggest that this alteration marks the lowest point at which currents have transported material.*

After twenty minutes' winding, the bucket came up full to overflowing with soft, sticky, green mud. A second haul produced similar results. A few echini were entangled in frayed rope-yarn attached to the small end of the bucket.

We returned to Auckland with about a third of a ton of sea-bottom. Mr. Cooper hospitably gave the party the use of his premises. After reserving samples for geological examination, the mud was placed in fine sieves, on which was played the garden-hose. On preliminary examination the mud, which was perhaps coloured by glauconite, showed but few shells; washing yielded about a spoonful of shells to a gallon of mud. An interesting feature is the occurrence of several species, such as Poroleda lanceolata and Loripes concinna, previously only known as Tertiary fossils.

It was resolved by the company that Mr. Suter take charge of the collections and distribute different groups to specialists who might undertake their study, and that types of new species should be ultimately placed in the Colonial Museum.

Under this arrangement the examination of the following Mollusca has been assigned to me. My labours have been much lightened by the kindness of Messrs. Suter and Murdoch, who sorted out the species and assisted me with preliminary determinations.

[Footnote] * Since writing the above I find that Admiral Wharton has already advanced this explanation—“Nature,” 25th February, 1897, p. 392.

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Pelecypoda

Nucula lacunosa, Hutton.

Nucula sulcata, A. Adams, P.Z.S., 1856, p.53. Id., Thes. Conch., iii, 1860, p. 153, pl. 229, f. 127 (not of Brown). N. lacunosa, Hutton, P.L.S.N.S.W, ix, 1884, p.528.

Several specimens in which the radii are more prominent than in shallow-water specimens.

Nucula nitidula, A. Adams.

Nucula nitidula, A. Adams, P.Z.S., 1856, p. 51. Id., Thes. Conch., iii, 1860, p. 150, pl. 229, f. 142.

A few specimens were procured.

Leda bellula, A. Adams.

Leda bellula, A. Admas, P.Z.S., 1856, p. 49. Id., Hanley, Thes. Conch., iii, 1860 p. 122, pl. 228, f. 74.

A species which occurred abundantly answers fairly to the above quotations. But the lithograph, fig. 25 of pl. v, “Leda,” in Conch. Icon., vol. xviii, is so bad a copy of the figure in the Thesaurus that it looks like a different species.

A. Adams, whose name is the danger signal for untrustworthy work, reports the species as taken by F. Strange in Australia. But, on the one hand, no Australian shell like this is known to me, and, on the other, Strange collected extensively in New Zealand. Indeed, he was the first, and for half a century the last. to dredge off the New Zealand coast, and discovered many of the species enumerated in this report. I am therefore disposed to think that “Australia” has been substituted here for “New Zealand.” The species before me is that known to all conchologists in New Zealand as Leda concinna. The figures of Leda concinna more nearly express the proportions of Poroleda lanceolata than any other member of the New Zealand fauna, and are incompatible with the traditional determination.

Leda fastidiosa, A. Adams. Plate I, figs. 1, 2.

Leda fastidiosa, A. Adams, P.Z.S., 1856, p. 49. Id., Hanley, Thes. Conch., in, 1860, p. 125, pl. 228, f. 82, 83.

A considerable number were dredged. The concentric sulci vary from the least trace to considerable development, but are never so coarse and regular as in the last species. Besides being smoother than L. bellula it is more inflated, and is further distinguished by a microscopic punctate pattern. The length of the figured specimen is 7 mm. and the height 4 mm.

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This species was first described from New Zealand, probably from Strange's collection, but has never been recognised again, either there or elsewhere, and was eliminated from the New Zealand list by Hutton (P.L.S.N.S.W., ix, 1884, p. 527).

Poroleda lanceolata, Hutton. Plate II, fig. 7.

Scaphula (?) lanceolata, Hutton, Trans. N.Z. Inst., xviii, 1885, p. 332. Poroleda lanceolata, Hutton, Macleay Memorial Vol., 1893, p. 86 (not Poroleda lanceolata, Tate, Proc. Roy. Soc. N.S.W., xxvii, 1894, p. 186 = Poroleda tatei, Hedley, “Victorian Naturalist,” xxi, Dec. 1904, p. 112)

The name of this species is involved in some confusion. Professor Tate, in March, 1894, introduced a new species, type of a new genus, under the title of Poroleda lanceolata But in the previous September-Captain Hutton had redescribed his fossil under the same name. Since Poroleda lanceolata was in current use for both the New Zealand and the Australian shell, I have proposed to distinguish that which Tate figured and described from the Gellibrand River beds of Victoria as Poroleda tatei.

In colour, texture, and all particulars save those of the hinge-teeth this species closely resembles Leda ensicula, Angas, L. lefroyi, Beddome, and L. huttoni, Tate. These five species might suitably be included in Poroleda.

Hitherto P. lanceolata has been known only as a Tertiary fossil. Mr. A. Hamilton has shown me a broken valve from off Anchor Island, Dusky Sound. In our 110 fathoms dredging it occurred plentifully. The size of the specimen drawn is-height, 3·85 mm.; length, 13·8 mm.; breadth of single valve, 0·9 mm.

Malletia australis, Quoy and Gaimard.

Solenella australis, Quoy and Gaimard, Voy. “Astrolabe,” Zool., iii, 1835, p. 471, pl. 78, f. 5–10.

A single valve.

Bathyarca cybaea, n. sp. Plate I, figs. 3, 4.

Shell small, oblong, short and inflated, inequivalve, a little inequilateral without impressed ray, posteriorly and anteriorly rounded, sinuate beneath the beak. Colour white, probably bleached. Sculpture finely reticulate. A series of delicate subequal evenly spaced riblets radiate from the umbo to the margin; as growth proceeds new riblets are intercalated till about fifty reach the margin. The radii are broken into short lengths by concentric growth-lines which produce minute prickles at the point of intersection. Beak much inrolled, at a third of the length of the shell. Ligamental area narrow

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Hinge-plate edentulous under the beaks, posteriorly with four nearly horizontal, anteriorly with four highly inclined small teeth. Interior rayed by imprint of external sculpture. Margin finely crenulate within except at byssal gape. Length, 3 mm.; height, 2·15 mm.; depth of single valve, 1 mm.

This species, represented by numerous specimens, is nearest allied to the Australian B. perversidens, from which it differs by the less development of the posterior side.

Pleurodon maorianus, Hedley.

Pleurodon maorianus, Hedley. “Records of the Australian Museum,” v., 1904, p. 87, fig. 14.

This species appeared in profusion.

Dacrydium pelseneeri, n. sp. Plate II, fig. 8.

Shell small, thin, translucid with a nacreous lustre, oblong inflated, straight on the anterior side, rounded dorsally and ventrally, almost angled at the anterior dorsal corner. Umbo slightly projecting. A thin membranous epidermis clothes the valve. Sculpture regular-spaced elevated growth-lines. Hinge with a few anterior teeth, and a long row of posterior teeth which increase in size as they recede from the chondrophore. Height, 2·2 mm.; length, 1·48 mm.

A pair of valves.

The above is the third species recorded from the Southern Hemisphere. D. albidum was described by Pelseneer (Result Voy. “Belgica,” Moll. 1903, p. 27, pl. viii, f. 10) from 200 fathoms in the South Pacific, near the Antarctic ice-barrier. D. fabale was described by myself (P.L.S.N.S.W., xxix, 1904, p. 199, pl. x, f. 39) from 100 fathoms off Wollongong, N.S.W. From Marion Island E. A. Smith has published Dacrydium meridionalis, but Bernard has shown (Journ. de Conch., xlv, 1897, p. 8) that this is probably a Philobrya.

The novelty appears to differ from D. albidum by its rough surface and by its greater length in proportion to height. From its nearer ally D. fabale it differs by the straight edge of the anterior margin, and by being smaller and proportionally shorter.

Cochlodesma angasi, Crosse and Fischer.

Periploma angasi, Crosse and Fischer, Journ. de Conch., 1864, p. 349: 1865, p. 427, pl. xi, f. 1.

A single valve.

Verticordia rhomboidea, n. sp. Plate II, figs. 12, 13, 14.

Shell inflated, subrhomboidal, inequilateral, right valve slightly clasping over the left along the dorsal margin, sub-

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stance very brittle, easily flaking off. Umbos incurved, rather distant, usually eroded. Lunule slightly excavated, dorsal area defined by the radial ribs. Sculpture, no incremental growth-lines, about twenty-two prominent sharp radial ribs which strongly denticulate the margin and imprint the nacreous interior, the surface has everywhere close-set grains which develop minute sharp prickles. Right valve with a large conical tooth under the lunule, and a posterior lateral beneath the dorsal area. Left valve with a minute tooth under the umbo and no lateral; ossicle not found. Height, 5mm.; length, 5·75mm.

Several specimens were taken.

The species apparently belongs to the subgenus Haliris, Dall. The genus, which is an acquisition to New Zealand, rarely occurs so high in the bathymetrical scale. Fischer proposed (Man. Conch., p.188) the term “verticordia zone” for the upper half of the abyssal region.

Cuspidaria trailli,Hutton. Plate II, figs. 9, 10, 11.

Neara trailli, Hutton, Cat. Marine Mollusca of New Zealand, 1873, p.62

One small and several broken shells were dredged. I have derived a figure from a specimen, 15 mm. in length, taken by Mr. A. Hamilton in Dusky Sound.

Cuna delta, Tate and May

Carditella delta, Tate and May, Trans. Roy. Soc. S.A., xxiv, 1900, p. 102. Cuna delta, Hedley, Mem. Austr. Mus., iv, 1902, p. 316.

Four separate valves.

Venericardia lutea, Hutton. Plate I, fig. 6.

Cardita lutea, Hutton, Man. N.Z. Mollusca, 1880, p. 159

The history of this species is complicated. Hutton applied his name to the shell introduced by Deshayes (P.Z.S., 1852 (1854), p. 101) as Cardita zealandica, because that clashed with Venericardia zeulandica, Potiez and Michaud (Gal. des Moll., ii, 1844, p. 166). Glancing aside, I might here remark that the latter species appears to have been misunderstood by all writers on the New Zealand Mollusca, and that the description of Potiez and Michaud is evidently meant for Chioue stutchburyi, Gray Finally, Hutton united (P.L.S.N.S.W., ix, 1884, p. 527) his C. lutea to the Chilian Cardita compressa, Reeve. This identification I am unable to support.

The species was a common one where we dredged. An example selected for figuring is 7 mm. long and 8 mm. high.

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Lucina cumingii, Ad. and Angas, Proc. Zool. Soc., 1863, p.426, pl. xxxvii, f. 20.

Loripes concinna, Hutton.

Loripes concinna, Hutton, Trans. N.Z. Inst., xvii, 1884 (1885), p.323. xviii, p. 363. Id, “Macleay Memorial Volume,” 1893, p.83, pl.ix, f. 90.

Three separate valves of this species were found. It has hitherto only been known as a Pliocene fossil. I am indebted to Mr. Murdoch for the identification.

Thyasira flexuosa, Montagu.

Tellina flexuosa, Montagu, Test. Brit., 1803, p. 72. Lucina flexuosa, Woodward's Manual, pl. xix, f.7.

A few separate valves were obtained. The species has not before been reported from New Zealand, but Mr. Suter informs me that it was noted as Cryptodon sp. by Captain Hutton in the Cat. Mar. Moll. N.Z., 1873, p.75 and that it is in the Colonial Museum from Waikanae Beach.

In the selection of the generic name I have followed Dr. Dall (Trans. Wagner Free Inst., iii, 1903, p. 1335).

Neolepton antipodum,
Plate I, fig. 5.

Kellya antipodum, Filhol, Compt. Rend. Acad. Sci. xci, 1880, p.1095. Neolepton antipodum, Bernard, Bull. Mus. d'Hist. Nat., vii, 1897, p. 314.

This species was represented by numerous separate valves It has also occurred to us in 100 fathoms outside Port Chalmers, and was taken by Mr. A. Hamilton in Foveaux Strait. It has not yet been recognised by local workers. The individual illustrated is 1 9mm high and 2·1 mm long.

This opportunity is taken of adding that Kellya suborbicularis, Montagu, should replace Kellya cycladiformis, Desh., of the Index Faun. Nov.-Zealand., p.91.

Erycina parva, Deshayes.

Kellia parva, Desh., Pro. Zool. Soc., 1855, p. 182. Id., Tryon, Proc. Acad. Nat. Sci. Philadelphia, (2), iii, 1872. p.231. Erycina acupuncta, Hedley, Mem. Austr. Mus., iv, 1902, p. 321, fig.60.

The species appears to be more common in New Zealand than in Australia. Mr. R. Murdoch suggested their identity to me. Comparing the few separate valves by which the species is known in Australia, I find that the New Zealand specimens are larger, being 3·6 mm. in length and 2·27 mm. in

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height, more solid, and with stronger concentric sulci. I believe the two to be variants of one species.

The New Zealand shell was named for me by Mr. H. Suter, for whom in turn it was determined by Dr. W. H. Dall, probably from co-types distributed by Hugh Cuming. The occurrence of the species in space and literature induces me to suspect an error parallel to that of Ledu fastidiosa, and to conjecture that it did not come from the Philippines, but that it was originally dredged in New Zealand waters by F. Strange during the cruise of H.M.S “Acheron” in 1849.

It has been detected by Mr. R. Murdoch in the Tertiary beds of Wanganui.

Cardium pulchellum, Gray.

Cardium pulchellum, Gray Dieffenbach's New Zealand, ii, 1843, p 252. Id., Reeve, Conch. Icon., ii, 1844, pl. viii, fig 42.

Single and broken valves were dredged in plenty.

Mactra scalpellum, Reeve.

Mactra scalpellum, Reeve, Conch. Icon., vii, Mactra, pl. xix, fig 106,

May, 1854. Id., Deshayes, Proc. Zool. Soc., 1854, p. 65, Feb. 10, 1855.

Several odd valves.

The species should be credited to Reeve, not, as is usual, to Deshayes, for the publication by Reeve was earlier by nearly a year.

Corbula zelandica, Quoy and Gaimard.

Corbula zelandica, Quoy and Gaimard, Voy. “Astrolabe,” Zool., iii, 1835, p. 511, pl. 85, figs. 12–14.

A single valve. The type of the species was obtained in the Hauraki Guif near by.

C. erythrodon, Lamk, is a much larger shell, differing in form and colour. It has been recognised by Lischke (Jap Meers Conch., i, 1869, p. 136) as a Japanese species, and ought, I think, to be struck off the New Zealand list.

Pteropoda.

This group is included here for convenience. As Pelseneer has demonstrated, they properly belong to Gastropoda.

Cavolinia tridentata, Forskål.

Anomia tridentata, Forskå, Descrip. Anim., 1773, p. 124. Cavolinia tridentata, Pelseneer, Chall. Rep., Zool., xxiii. 1888, p. 83.

A few specimens.

This species is an addition to the New Zealand fauna.

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Cavolinia trispinosa, Lesueur.

Hyalaa trispinosa, Lesueur, Dict. Sci. Nat, xxii, 1821, p.82. Cavolinia trispinosa, Pelseneer, Chall. Rep., Zool., xxiii, 1888, p. 76.

A few specimens.

Cavolinia inflexa, Lesueur.

Hyalaa inflexa, Lesueur, Nouv. Bull. Soc. Philom., iii, 1813, p. 285, pl. v, fig. 3. Cavolinia inflexa, Pelseneer, Chall. Rep., Zool., xxiii, 1888, p. 85.

A couple of specimens.

Cavolinia, sp.

A variation or ally of C. longirostris is present, but the specimens are not suitable for description. I have taken this species off the Australian coast, and expect to present an account of it shortly.

Cuvierina columnella, Rang.

Cuvieria columnella, Rang., Ann. Sci. Nat., xiii, 1827, p. 323, p. xlv, f. 1–3. Cuvierina columnella, Pelseneer, Chall. Rep. Zool., xxiii, 1888, p. 84.

A single specimen, which adds a genus as well as a species to the fauna of New Zealand.

It may be here noticed that Cymbulia parvidentata, Pelseneer (Chall. Rep., Zool., xxiii, 1888, p. 99, pl. ii, f. 12, 13) has been overlooked by the compilers of the “Index Faunæ Novæ-Zealandiæ.”

Heteropoda.
Atlanta, sp.

Fragments of Atlanta, a genus not recorded from New Zealand, are present, but are too imperfect for specific determination.

Explanation of Plates I and II.
Plate I.
  • Figs. 1, 2. Different aspects and magnified sculpture of Leda fastidiosn, A. Adams.

  • Figs. 3, 4. Interior and exterior of Bathyarca cybæa, Hedley.

  • Fig. 5. Exterior and binge of Neolepton antipodum, Filhol.

  • Fig. 6. Exterior of Venericardia lutea, Hutton.

Plate II
  • Fig. 7. Hinge and interior of Poroleda lanceolata, Hutton.

  • Fig. 8. Interior of Dacrydium pelseneeri, Hedley.

  • Figs. 9, 10, 11. Various aspects of Cuspidaria trailli, Hutton.

  • Figs. 12, 13, 14. Various aspects and magnified sculpture of Verticordia rhomboidea, Hedley.