Art. XVII.—New Species of Mollusca, from various Dredgings taken off the Coast of New Zealand, the Snares Islands, and the Bounty Islands.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 51, 1919, Page 130

Art. XVII.—New Species of Mollusca, from various Dredgings taken off the Coast of New Zealand, the Snares Islands, and the Bounty Islands. By Miss M. K. Mestayer Communicated By R. L. Mestayer [Read before the Wellington Philosophical Society, 24th July, 1918; received by Editors, 30th August, 1918; issued separately, 26th May, 1919.] Plate VIII. The species described or referred to in the following paper were, with one exception, obtained from dredgings taken by Captain Bollons, of the s.s. “Hinemoa,” in various parts of the Hauraki Gulf, off the North Cape, and off the Bounty and Snares Islands. Scissurella regia and Discohelix hedleyi, of which the dimensions are for the first time given, are from dredgings off the Three Kings Islands and the North Cape. I wish to acknowledge my great indebtedness to Mr. C. Hedley, Dr. J. A. Thomson, and the late Mr. H. Suter for their unfailing kindness and help; and to Miss J. K. Allan for the trouble she has taken over the drawings from which the figures are prepared. Family Scissurellidae. Scissurella regia Mestayer. I take this opportunity of correcting an oversight in connection with my paper in vol. 48 of the Transactions.* M. K. Mestayer, Preliminary List of Mollusca from Dredgings taken off the Northern Coast of New Zealand, Trans. N.Z. Inst., vol. 48, pp. 122–28, pl. xii, 1916. In the description of Scissurella regia on page 124 the measurements of the holotype were accidentally omitted. They are as follows: Height, 2mm.; major diameter, 2.5mm.; minor diameter, 2 mm. At the same time I record the finding of two imperfect specimens—one in a dredging taken by the “Nora Niven,” sixty miles east of Lyttelton, in 100 fathoms, and the other in a dredging in Pickersgill Harbour, Dusky Sound. A wider range is indicated for this species than at first supposed. Schismope subantarctica Hedley. This species occurs at Lyall Bay, Wellington, N.Z. It was described by Hedley† C. Hedley, Australasian Antarctic Expedition, vol. 4, pt 1, p. 36, pl. v, figs. 54, 55, 1916. from the Macquarie Islands. I found it also in a dredging off the Snares Islands in 50 fathoms. Family liotiidae Gray. Genus liotia Gray, 1847. Liotia suteri n. sp. (Plate VIII, figs. 1–3.) Bounty Islands; 70 fathoms. Shell small, somewhat discoidal. Whorls 3, compressed, with a rather broad peripheral keel, which gives a serrated appearance to the edge of the upper surface. Spire flat. Protoconch of one minute flat whorl. Suture

distinct, serrated, bordered below by a narrow groove and a nodulous rib. Body-whorl apparently smooth, but in a good light and under a strong pocket-lens very fine hair-like radial lines are to be seen. Upper and under surfaces convex. Aperture circular, with a heavy double varix, bearing four deep pits. In the holotype the aperture is closed by a dark-brown raised spiral disc. covered with fine radial threads, which may perhaps be the operculum, though it has somewhat the appearance of a small polyzoan. Umbilicus deep, moderately open, revealing all the whorls; margined by a rather broad radially ribbed groove. Colour light-cream; the paratype is slightly browner. Measurements.—Major diameter, 3 mm.; minor diameter, 2 mm.; thickness, 1·5 mm. Material.—The holotype and one paratype (juvenile). Remarks.—Mr. Suter's comment on it was, “Liotia n. sp. distinct from Liotia serrata Suter,” the type of which is in his collection. Liotia suteri slightly resembles two species from the Philippines — (1) Liotia discoidea (Reeve),* Man. Conch. (1) x, p. 109, pl. 36, fig. 3. in its depressed form and peripheral keels, and (2) Liotia crenata (Kiener),† Man. Conch. (1) x, p. 111, pl. 36, figs. 12, 13. in its heavily variced aperture and smooth base. It differs from Liotia crenata (Kiener) in that the whorls only show one peripheral keel above the suture, and from Liotia discoidea (Reeve) in having a smooth base and much more heavily variced aperture. It seems to be a rather rare species, as I have had a considerable amount of material dredged at various stations off the Bounty Islands, and these are the only specimens obtained. Both holotype and paratype are a good deal water-worn, especially the latter, which is not quite perfect. Both specimens are in my collection. Family Orbitestellidae Iredale. Orbitestella hinemoa n. sp. (Plate VIII, figs. 7–9.) Snares Islands; 50 fathoms. Shell minute, translucent, thin yet strong, discoidal. Whorls 3, sharply angled; periphery vertical with a strong central keel nearly one-third its width. Protoconch minute, one whorl. Spire only very slightly raised on the convex surface. Base concave. Sculpture, one strong peripheral keel, and faint traces of a raised spiral thread near the suture; many fine raised radials extend from the suture into the widely open unbilicus. Aperture quadrate. Outer lip thin, sharp, wavy. Colour white. Measurements.—Holotype: Diameter, 1 mm.; thickness, ⅓ mm. Material.—The holotype and forty-one paratypes from the type locality. The holotype is in the Dominion Museum. Remarks.—There is a good deal of variation in the distinctness of the sculpture; on the holotype the radial threads are indistinct, but they are very distinct on a paratype, which is placed with it on that account. The species owes its specific name to the ship from which the dredging was taken. Mr. Hedley says it is allied to Orbitestella bastowi (Gatliff), the type of this genus; unfortunately, I have been unable to see either the figures or description of Gatliff's species, so am unable to say how it differs from O. hinemoa. The sculpture is so fine that though the figures (7–9) show it quite correctly, yet a moderately high power on the microscope is required to bring it out.

As the Proceedings of the Malacological Society of London are not always readily accessible in New Zealand, I append Iredale's definition of this genus:— “Orbitestella gen. nov. “I propose this name, and designate as type Cyclostrema bastowi Gatliff (Proc. Rov. Soc. Vic. (n.s.), vol. xix, 1906 p. 3, pl. ii, figs. 8–10). I also indicate it as representative of a new family Orbitestellidae, which is composed of a series of minute marine molluscs with the following characters: Shell thin, pellucid, discoidal, dextral, of few whorls and of peculiar sculpture; widely umbilicate, columella vertical, aperture never variced, irregular in shape, edges thin. “I had hoped to describe the group, giving figures, but at present this is impossible. I have species from various parts of New Zealand, the Kermadecs, Lord Howe Island, Norfolk Island, New Caledonia, Sydney Harbour (New South Wales), north coast of Tasmania, and Port Lincoln (South Australia)—in fact, every austral locality from which I have received a parcel of fine shell sand or fine dredgings. Commonly live shells have been secured when live sand was received. All the species are very minute, and I have about a dozen distinct species, divisible into two groups, and I hope later to thoroughly elaborate the family with good figures.”* T. Iredale, More Molluscan Name-changes, Proc. Malac. Soc., vol. 12, part vi, p. 327, 1917. Family Architectonicidae. Discohelix hedleyi Mestayer. With regard to this species I regret that, as in the case of Scissurella regia, in my paper previously referred to the measurements of the holotype were accidentally omitted. They are: Height, 0·5 mm.; diameter, 1 mm. Family Epitoniidae. Crossea cuvieriana n. sp. (Plate VIII, fig. 10.) Off Cuvier Island, Hauraki Gulf, N.Z.; 38–40 fathoms. Shell small, turbinate, rather thin. Whorls 3, the last rather large, convex. Protoconch small, smooth, glossy, about two whorls. Sculpture, five spiral ribs, of which the upper two are stronger than the others; all are characterized by very fine close threads crossing them. Even under a strong pocket-lens the tops of the spirals appear quite smooth, but a 3 in. objective on the microscope shows that the spirals are crossed by the threads. The axial sculpture is formed by strong lamellae, somewhat unevenly spaced, which become rather crowded on the base; between the suture and the two upper spirals the interstices are about four times the width of the lamellae. The basal sculpture resembles Crossea cancellata Ten.-Woods, but in that species the spirals are smooth. Umbilicus very small. The umbilical rim is very strong and finely crenulated like the spirals. Aperture vertical, circular, decidedly canalicu-lated at the base. The outer lip is slightly channelled by the five spirals, inner lip thin, sharp, only slightly reflexed towards the umbilical rim. Colour white or very light brown; dull surface. Individual specimens vary somewhat in the density of the shell, the white specimens being more translucent than the brown ones.

Measurements.—Height, 3 mm.; diameter, 3 mm. Material.—Holotype and six paratypes from the type locality; one from off the Bounty Islands, 70 fathoms; and two from off the Hen and Chickens Islands, Hauraki Gulf, 25–26 fathoms. Remarks.—This species is allied to Crossea cancellata Ten.-Woods,* H. Suter, Manual of the New Zealand Mollusca, p. 324, 1914. from which it is readily distinguished by the five crenulated spirals. The strength of the sculpture varies slightly in different individuals, and the foregoing description is based on the white holotype and on a well-sculptured paratype, which is placed with it in the Dominion Museum. Mr. C. Hedley saw a juvenile specimen and informed me that he considered it a new species, so I examined my various dredgings and obtained some much larger specimens. Family Turritidae. Leucosyrinx thomsoni n. sp. (Plate VIII, fig. 5.) Off Hen and Chicken Islands, Hauraki Gulf, N.Z.; 25–26 fathoms. Shell small, fusiform, thin. Spire a little higher than the aperture. Protoconch, two whorls, globular, white, smooth, dull. Whorls 5 (holotype 4), sharply shouldered, convex, contracting rapidly to the canal, which is very short, open, and slightly reflexed to the left. Anal notch very slight, near the rather deeply impressed suture. Sculpture, three sharp spiral ribs on the periphery, and many fine spiral threads on the base and canal. On the sloping shoulder between the suture and the first spiral are two or three very fine spiral threads, which are, however, almost obscured by the fine sharp axial threads which run slightly obliquely from spire to base, and are somewhat irregularly spaced. Columella short and smooth. Outer lip thin, channelled by the spiral ribs; inner lip merely a thin glaze on the columella and body-whorl. Colour white or creamy. Operculum unknown. Animal unknown. Measurements.—Holotype: Height, 3 mm.; diameter, 1·5 mm. Material.—The holotype and fifteen paratypes from type locality; and from the Bounty Islands, Cuvier Island, Auckland Islands, and Dusky Sound, only one specimen from each. Thus it has a fairly wide range. Remarks.—This species is rather variable in sculpture, but the three strong spirals on the body-whorl, and the very short canal, are distinctive characters. Some of the young paratypes from the type locality have much stronger spirals; and there is also slight variation in the axial sculpture, some showing it more than others. The holotype is a young specimen of only four whorls; a paratype of five whorls which has been used with it in the above description also shows a fine spiral thread between the first and second ribs. Both these specimens are in the Dominion Museum. The nearest ally of this species is the following one, Leucosyrinx cuvierensis, which also occurs in the Hauraki Gulf. The species is named in honour of Dr. J. A. Thomson, Director of the Dominion Museum. Leucosyrinx cuvierensis n. sp. (Plate VIII, fig. 4.) Off Cuvier Island, Hauraki Gulf, N.Z.; 38–40 fathoms. Shell small, fusiform, fragile. Spire slightly shorter than the aperture and canal. Protoconch, two whorls, rounded, smooth, dull. Whorls 3,

regularly increasing, shouldered, convex, contracting sharply to the canal. Sculpture, on the body-whorl four spiral ribs; only the upper two show on the spire-whorls. Some specimens have an extra small spiral thread between the main ribs; on the holotype it is between the second and third ribs. The axial sculpture consists of fine sharp nearly equidistant threads from the apex to the basal rib, rendering the spirals nodulous. From the basal rib only fine growth-lines show along the canal. The anal notch is merely a curve on the sloping shoulder near the suture, and is easily overlooked. Suture rather deeply impressed. Canal fairly long, widely open, inclined to the left, with a very slight backward curve. Outer lip sharp, convex; inner lip merely a thin glaze on the columella. Columella short, vertical. Colour a dirty white. Operculum unknown. Animal unknown. Measurements.—Height, 4·5 mm.; diameter, 2 mm. Material.—The holotype and three paratypes from type locality; fifteen from off Hen and Chickens Islands, Hauraki Gulf; and seven from five miles W. ½ N. from Cuvier Island, Hauraki Gulf, 38 fathoms. Remarks.—The sculpture is rather variable; sometimes the spirals are more prominent than on the holotype, and in some specimens the axials are coarser and wider apart. In either case the four spirals are a constant character, as even if the extra spirals are present they are only fine threads. One or two of the paratypes at first sight resemble L. thomsoni, from which they are easily distinguished by the fewer spirals and absence of spiral sculpture on the base. Mr, C. Hedley, who saw specimens of both species, said they were new species of the genus Leucosyrinx. They do not seem to be very closely allied to any other New Zealand species, either Recent or fossil. Veprecula cooperi n. sp. (Plate VIII, fig. 6.) Off the Hen and Chickens Islands, Hauraki Gulf, N.Z.; 25–30 fathoms. Shell small, fragile, fusiform, slender, prickly. Spure pagodiform. Whorls 5, plus a three-whorled embryonic apex, which is finely longitudinally ribbed; whorls convex, contracting rapidly. Sculpture, four sharp raised spiral ribs, crossed by about twelve equally sharp raised axial ribs, which disappear below the fourth spiral, and are interrupted above by the broad anal fasciole. The intersection of the ribs is marked by a sharp prickle; between the raised ribs are deep oblong pits, the surface of which is smooth and dull. The anal fasciole is crossed by fine crescentic growthlines, and bordered on its outer edge by a narrow double thread. Anal slit nearly 1 mm. in length. Suture distinct, serrated by the lowest spiral. Coming from inside the vertical columella and covering the base and canal are about twelve fine equidistant spiral threads. Canal short, open, very slightly recurved. Outer lip thin, sharp; in the holotype it is slightly thickened by the last axial rib; the inner surface is deeply grooved by the spirals, and less so by the axials. Colour uniform light biscuit-brown. Operculum unknown. Animal unknown. Measurements.—Holotype: Height, 5 mm.; diameter, 2 mm. Material.—Eighty-six from type locality, and forty-nine others from the Hauraki Gulf and North Cape, at depths ranging from 26 to 73 fathoms. Remarks.—So far as I can see at present, this species has no near ally in the New Zealand molluscan fauna. Its nearest ally seems to be

Figs. 1–3—Liotia suteri n. sp. Fig. 4.—Leucosyrinx cuvierensis n. sp. Fig. 5.—Leucosyrinx thomsoni n. sp. Fig. 6.—Veprecula cooperi n. sp. Figs. 7–9.—Orbitestella hinemoa n. sp. Fig. 10.—Crossea cuviana n. sp. Fig. 11.—Pecten aff. transenna Suter.

Veprecula vepratica (Hedley), of Australia.* Mem. Austral. Mus., No. 4, p. 384, fig. 97. Mr. Hedley, who kindly compared the species, says, “It seems to differ from the New South Wales Veprecula vepratica by more radial riblets and by the protoconch being more delicately sculptured.” V. hedleyi (Melvill),† Proc. Malac. Soc. London, vol. 12, pts. iv-v, pp. 189–90, 1917. which has a longer canal, is also allied to this species. It is named in honour of the late Mr. C. Cooper, of Auckland, who directed my attention to it. Though I have a fairly large number of specimens, yet owing to their fragility very few are perfect. Melvill in his paper proposed the name Veprecula, as a subgenus of his Clathurina; but Hedley in A Check-list of the Marine Fauna of New South Wales, Part I, page 83, 1918, treats it as a full genus; and it is on his advice it is so treated here. Family Pectinidae. Pecten aff. transenna Suter. (Plate VIII, fig. 11.) Six and a half miles E. 5° N. from the North Cape, N.Z.; 75 fathoms. In the Manual of the New Zealand Mollusca, 1914, Suter describes a minute Pecten he obtained in a dredging taken off the Snares Islands (p. 881, pl. 52, fig. 3). While examining a dredging taken by Captain Bollons off the North Cape I found a single valve of a Pecten totally unlike any I had so far seen. Some time ago I sent it to Mr. Suter for his opinion, and his note on it is: “Pecten aff. transenna Suter. My specimens from the Snares are evidently not adult, only 3.4 mm. by 3 mm., and much worn. Your specimen, a left valve, is perfect, and I am much inclined to take it as representing my species.” He also suggested publishing a photograph of it. It is on Dr. J. A. Thomson's recommendation that the following description of my specimen is published, with the accompanying figure. Left valve small, roundly ovate, with straight dorsum and small sub-equal ears. Colour light-cream, opaque. Valve moderately convex, with twelve primary radial ribs, running almost to the umbo; increased by secondary riblets to twenty-four at the margin, with traces of two or three more rudimentary riblets; these are crossed by about thirty raised concentric threads, which form small rounded tubercles on the radials. Beak slightly anterior, a little raised, round, smooth. Ears small, not distinctly marked off from the disc; their sculpture similar to the disc. Anterior end a little shorter, convex, receding below, slightly sinuated below the ear: posterior end nearly straight to the fourth riblet on the ear; thence rapidly descending, convex. Ventral margin broadly convex. Hinge-line straight, with a minute resilium beneath the umbo. Interior creamy, shining, grooved by the radials, with the concentric threads clearly visible. Margin slightly denticulated by the ribs. At about 0.5 mm. from the edge there is a well-marked groove (possibly a rest period), and the growth has been continued on a slightly different plane, the last three or four concentric threads being at a slight angle to the rest of the shell, so that it almost looks as if it had a tiny frill along its front edge. Measurements.—5 mm. by 4 mm.