Art. XXXVII.—On the Mollusca of Auckland Harbour.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 8, 1875, Page 304

Art. XXXVII.—On the Mollusca of Auckland Harbour. By T. F. Cheeseman, F.L.S. [Read before the Auckland Institute, 14th June, 1875.] The publication of Captain Hutton's excellent catalogue of the Marine Mollusca of New Zealand has afforded me an opportunity of naming the shells which, for some years past, I have collected in and about Auckland Harbour. While engaged in this work, it occurred to me that a list of the species noticed, together with a few cursory remarks, might be of some value as a contribution towards the question of the geographical range of our shells; a point on which very little appears to be known. With this view I have prepared the following sketch, which I have now the pleasure to submit to the notice of the Institute. For the purposes of this paper, I shall consider Auckland Harbour to extend in a northerly and easterly direction as far as Rangitoto and Brown's Island, and to be bounded on the west by a line drawn from Kauri Point to the mouth of the Whau River. From the great irregularity in the coast line—large bays and inlets stretching back for considerable distances—it is difficult to estimate the area with any approach to exactness, but it is probably not less than eighteen square miles. The depth is nowhere very great: an irregularly shaped depression between the North Head and the Bean Rock Lighthouse exceeds fifteen fathoms, and off Stokes' Point a narrow channel, with a depth of from twelve to thirteen fathoms extends for a considerable distance. No part of Rangitoto Channel, however, exceeds eight fathoms, and the broadest part of the harbour—that between the Tamaki Heads

and Rangitoto—has only an average depth of four or five. Many of the bays are very shallow, and extensive mud-banks, often covered with Zostera, are daily exposed at low-water. The distribution of the Mollusca is well known to be considerably influenced by depth, and the sea-bed has, in consequence, been divided by the late Professor Edward Forbes and others into four “Zones” or areas, as follows:—First, the littoral zone, or the space between the tide-marks; second, the laminarian zone, extending from low-water mark to ten or fifteen fathoms; third, the coralline zone, from fifteen to fifty fathoms; and lastly, the deep sea zone. It is, of course, only the first two of these regions that we are concerned with in Auckland Harbour. Commencing, then, with the littoral zone, we shall find that no part of it is without molluscan inhabitants. When the coast is at all rocky, large areas are covered with the common oyster (Ostrea mordax), often associated with the mussel (Mytilus smaragdinus.) A peculiar assemblage of species is found near high-water mark. Littorina diemenensis is usually in large numbers, filling little chinks and crevices, but often also scattered as it were broadcast over the surface of the rocks. Another little shell, Adeorbis varius, generally accompanies it, but is easily overlooked from its small size. A curious minute shell, apparently allied to Leuconia, a sub-genus of Melampus, is often found gregarious under stones. Mytilus ater and Nerita atrata are also frequently seen near the upward limits of the tide. Further down the strand, projecting rocks and overhanging ledges are sprinkled over with a variety of small whelks, of which Purpura quoyi, Buccinum testudineum and B. lœvigatum are prominent forms. The larger Purpura textiliosa is also tolerably common, but P. haustrum appears to be rare. The phytophagous species are now well represented, especially where the rocks are covered with Hormosira or other sea-weeds. Turbo smaragdus, Labio zealandicus, L. subrostrata, and Cerithium bicarinata, are all abundant. Two or three species of Limpets and a Siphonaria are not uncommon in suitable localities. The smaller rock-pools, that are generally fringed with Corallina, Jania, and the finer sea-weeds, usually harbour a few species of Rissoa and other minute shells; the larger ones, with coarse weeds, are in a great measure occupied by Turbo and Cerithium. In all, numerous Chitons can be found; of these C. pellis-serpentis and C. quoyi principally affect the higher pools, while C. longicymbus and C. sulcatus are more common near low-water mark. Katharina violacea and Tonicia undulata, both occur under stones in the large and deep basins, but are not abundant. The finest of all our Chitons, Acanthopleura nobilis, has been found on exposed rocks at Rangitoto, but appears to be rare.

A few species are seen only on the verge of low-water mark, but are for the most part stragglers from the next zone. Fusus zealandicus and F. dilatatus can now and then be picked underneath ledges, sometimes accompanied by Triton spengleri. Under stones Tugali elegans and Fusus linea are often to be observed, together with a number of minute shells, of which Eulima chathamensis and two undescribed species of Columbella deserve mention. Parmophorus australis, one of the most singular of our molluscs, can also be occasionally collected. The inky black colour of the animal, and its large size compared with the shell—which indeed it almost entirely conceals—will cause it to be easily recognized when once seen. Crenella discors, a rather handsome bivalve, should also be mentioned here, from its curious habit of spinning a nest for itself under the roots of sea-weeds or among Sponges and Tunicata. Boring molluscs are well represented in the space between the tide marks; the sandstone rocks being everywhere preforated by two species of the Pholadidœ (Pholœs similis and Pholadidea tridens) and by Lithodomus truncatus. The intensely hard basaltic lava around Rangitoto alone appears to successfully resist their attacks. Venerupis reflexa often shelters in the deserted burrows of the Pholas, but is capable of excavating for itself in the softer rocks. The ravages of the Teredo in the timber of our wharves and jetties is too well known to need more than simple mention here. Where mud or sand takes the place of rocks, we find a somewhat different assemblage of species. Amphibola avellana can everywhere be seen crawling among the mangroves that line the sides of the more sheltered bays. The affinity of this curious species is with the tropical genus Ampullaria, which includes a large number of forms, all inhabitants of fresh water, and many of which are well-known in India and other countries under the name of Pond-snails. Hidden among the roots of the sedges and rushes that often fringe the line of high-water mark Melampus costellaris may be observed, sometimes in great abundance. A few fluviatile shells—principally species of Hydrobia or of allied genera—are often found in pools that are only entered by the sea at spring-tides, or during storms. The extensive mud-flats and sand-banks that are laid bare by the recess of the tide are the favourite habitat of many species of bivalves. The Cockle (Chione stutchburyi) prefers sheltered and rather muddy localities; the Pipi (Mesodesma chemnitzii) inclines to a more sandy and exposed situation. Hemimactra ovata is plentiful, buried in the muddy banks of the tide streams. Other common forms are Mesodesma cuneata, Tapes intermedia, Tellina deltoidalis, etc. Accompanying these, and to a great extent preying upon them, are some of the Zoophagous Gasteropods, the most abundant of which are Buccinum maculatum, B. costatum, and (near low-water mark) Ancillaria

australis. On Zostera beds, Haminea obesa can always be found, and in some localities in countless thousands. A very different shell—Gibbula nitida—is also of constant occurrence. The largest of all our shells, Pinna zealandica, is also not uncommon, generally buried to nearly the top of its valves in the mud. At certain seasons of the year a species of Aplysia, apparently yet undescribed, can be picked up in some numbers, as also can a member of the curious genus Pleurobranchœa, and a few small Nudibranchs. Pecten laticostatus is occasionally seen, as are Mysia zealandica and Solemya australis, but these are more common in the next zone. We have now to consider the inhabitants of the Laminarian zone; an acquaintance with which we can only make by means of dredging, or by examining the refuse thrown up after heavy gales. The first of these methods is the most satisfactory, but is only applicable where the bottom is tolerably even, or composed of sand and mud. From the few dredgings I have been able to make, it appears that Venus mesodesma, Tapes intermedia, and Corbula zealandica are by far the most common species; the first named often forming extensive banks. Other forms of frequent occurrence are Zenatia acinaces, Anatina tasmanica, Nucula consobrina, and N. margaritacea. In sandy places a species of Philine often comes up in the dredge, usually accompanied with the pretty little Monilea zealandica and a fine Pleurotoma, as yet undescribed. Fusus stangeri, Marginella albescens, and Venericardia zealandica, are also commonly met with. Terebratella rubicunda is often seen attached to stones, and is also abundant about low-water mark at Rangitoto; but in no locality in the harbour have I observed it at all approaching the size that it attains on more exposed coasts. In the deeper portions of the harbour Trichotropis inornata, Cerithium terebelloides, and a new species of Natica are tolerably plentiful. Murex octogonus is sometimes dredged; but the commonest whelk is Buccinum luridum, which occurs everywhere, and seems to take the place below low-water mark that its near ally, B. costatum occupies above. Of the Chitons, Cryptoconchus monticularis is common on the reefs, and is occasionally exposed at low spring-tides; a few smaller species also occur, of which a pretty little Acanthochœtes, not yet identified, deserves mention. Of the shells that inhabit rocky ground, and are consequently only seen after storms, Haliotis iris and Imperator cookii, must not be passed over without notice: although both are common on many portions of our coasts, they are decidedly rare in Auckland Harbour. It remains for me to mention the occasional occurrence of a Cephalopod (Sepioteuthis major) which seems to be a summer visitant only, I once observed a smaller species apparently allied to Octopus, but neglected to

preserve the specimen and so cannot now speak confidently as to its genus. Dead shells of Spirula lœvis, and also of the well-known “sea snails,” Ianthina exigua and I. communis, are frequently cast up after north-east gales; but as these species live in tke open sea only, we have no right to claim them as inhabitants. The subjoined catalogue contains the names of 175 species, arranged as follows:—Cephalopoda, 2; Heteropoda, 2; Gasteropoda, 120; Lamellibranchiata, 50; Brachiopoda, 1. Several of these are not mentioned in our catalogues, and are probably new to the New Zealand Fauna. I must here mention my obligations to Captain F. W. Hutton, of the Otago Museum, who has most kindly assisted me in determining several of the species, and who will probably soon describe some of the new forms. Before concluding this sketch, I may perhaps be allowed to draw the attention of such of our members who have a taste for Natural History to the wide field still remaining for research in the invertebrata of our seas. In no other branch of the New Zealand Fauna does so much remain to be be done. Of the lower classes, as for instance: the Sponges, Zoophytes, and Annelids, hardly anything is known; in fact only a few conspicuous species appear to have been collected. It is probable that not one-half the Crustacea have been obtained. We are better acquainted with the Echinoderms, thanks to the excellent little catalogue issued by the Geological Survey; but in this class it is obvious that many additions will be made. The Mollusca have undoubtedly received the most attention, but even here large families have been almost entirely neglected. In confirmation of this I need only point to the Nudibranchs, which in Britain alone, number about 112 species, whilst here only three have as yet been described. There is no reason, so far as I am aware, for supposing that this order is less abundant here than at home; and certainly at least a dozen forms can be observed in Auckland Harbour, a locality which cannot be said to be productive in species as compared with other portions of the coast. It must also be remembered that no attempt at dredging worthy of the name has as yet been made; and yet it would be difficult to estimate the number of entirely new species, of all orders, and the valuable information as to the habits and distribution of those already known which will be obtained by the systematic use of the dredge at even moderate depths. Deep sea dredging, say at a greater depth than 100 fathoms, is too laborious and expensive an undertaking for private individuals, but in the comparatively shallow water near the shore a great deal might be done. There are other questions, too, that require attention besides that of “species hunting,” and perhaps of more importance. The geographical distribution and relative abundance of the species is one that has hardly

been touched, and yet it will yield most valuable results. There are also the phenomena connected with the growth and development of each individual form—perhaps the most interesting portion of the subject. Every species has a history of its own—always suggestive and full of interest—but in too many cases the historian is yet to be found. There is its birth; its first transient wandering existence; later, its adult life—whether buried in the sand of the sea bottom or anchored by cables capable of resisting the heaviest surf—whether boring deep in submerged timber or excavating chambers in the hardest stone—now, as the Oyster, immovably bound to the exposed rock, or, as the Fusus, crawling slowly over it—now darting rapidly through the water, or floating on its surface, the sport of every wind and tide; there is its food—its means of obtaining it—its special habitat—its relations to the species immediately surrounding it—its economic value to man. All these are chapters in the life-history of every species, and chapters which in many instances are yet to be written. The table of contents is indeed prepared; but the contents themselves—the material which is to give the work its real value—still remains to be filled in. List of species observed in Auckland Harbour:— I. Cephalopoda. Sepioteuthis major, Gray. Spirula lœvis, Gray. II. Heteropoda. Ianthina exigua, Lamark. " communis, Lamark. III. Gasteropoda. Murex octogonus, Gray. Fusus zealandicus, Quoy. " dilatatus, Quoy. " stangeri, Gray. " plebeius, Hutton. " lineatus, Gray. " linea, Martyn. " n. sp. " duodecimus, Gray. " nodosus, Martyn. Pleurotoma buchanani, Hutton. " n. sp. " n. sp. " n. sp. " n. sp. Daphnelia letourneuxiana, Crosse. Triton australe. " spengleri. Buccinum maculatum, Martyn. " costatum, Quoy. " luridum, Hutton. " lavigatum. " testudineum, Quoy. " n. sp. (?) Purpura haustrum, Martyn. " textiliosa, Lamark. " scobina, Quoy. " quoyi, Reeve. Ancillaria australis, Quoy. Voluta pacifica, Lamark. " sp. Marginella albescens, Hutton.

Columbella, n. sp. " n. sp. Natica, n. sp. Scalaria zelebori, Dunker. " lineolata, Kiener. " sp. (?) Chemnitzia zealandica, Hutton. Odostomia lactea, Angas. " sp. Eulima chathamensis, Hutton. Struthiolaria nodulosa, Lamark. " vermis, Martyn. Trichotropis inornata, Hutton. Cerithium bicarinata, Gray. " subcarina, Sowerby. " kirki, Hutton. " terebelloides, Von Martens. " n. sp. Littorina diemenensis, Gray. Rissoa, sp. " sp. " sp. " sp. Turritella rosea, Quoy. " fulminata, Hutton. Calyptrœa maculata, Quoy. Trochita tenuis, Gray. Crypta costata, Deshayes. " contorta, Quoy. " unguiformis, Lamark. Nerita atrata, Lamark. Turbo smaragdus, Lamark. " granosus, Lamark. Imperator cookii, Lamark. Adeorbis varius, Hutton. Rotella zealandica, Chenu. Chrysostoma, sp. Polydonta tuberculata, Gray. " tiarata, Quoy. Labio zealandicus, Quoy. " cingulatus, Quoy. " subrostrata, Gray. Euchelus bellus, Hutton. Diloma nigerrima, Linn. Ziziphinus tigris, Martyn. " selectus, Chemintz. Cantharidus elegans, Gmelin. Monilea zealandica, Hutton. Gibbula sanguinea, Gray. " nitida, Adams. " n. sp. Haliotis iris, Lamark. Tugali elegans, Gray. Parmophorus australis, Lamark. Tectura pileopsis, Quoy. Patella, sp. Nacella radians, Gmelin. " sp. Chiton pellis-serpentis, Quoy. " quoyi, Deshayes. " sulcatus, Quoy. " longicymbus, De Blainville. Tonicia undulata, Quoy. Acanthopleura nobilis, Gray. Acanthochœtes porphyreticus, Reeve. " hookeri, Gray. Katharina violacea, Quoy. Cryptoconchus monticularis, Quoy. Buccinulus albus, Hutton. " n. g. (?) Cylichna striata, Hutton. Bulla quoyi, Gray. Haminea obesa, Sowerby. Philine angasi, Crosse. Aplysia, sp. Pleurobranchœa, sp. Doris, sp. " sp. " sp. " (?) sp. Onchidoris tuberculatus, Hutton. œolis, sp. " (?) sp. Onchidella nigricans, Quoy. Siphonaria zealandica, Quoy. Melampus costellaris, Adams. Leucoma (?) sp. Amphibola avellana, Gmelin. IV. Lamellibranchiata. Barnea similis, Gray. Pholadidea tridens, Gray. Teredo antarctica, Hutton. Corbula zealandica, Quoy. Anatina tasmanica, Reeve. Myodora striata, Quoy. Chamostrea albida, Lamark. Hemimactra ovata, Gray. Tenatia acinaces, Quoy. Psammobia stangeri, Gray. " lineolata, Gray. Hiatula nitidula, Gray. " sp. Tellina deltoidalis, Lamark. " lintea, Hutton. Mesodesma chemnitzii, Deshayes.

Mesodesma zealandica, Potier and " cuneata. Chione lamellata, Lamark. " yateri, Gray. " costata, Gray. " stutchburyi, Gray. " dieffenbackii, Gray. " mesodesma, Quoy. Dosinia anus, Phillipi. " subrosea, Quoy. Tapes intermedia, Quoy. Venerupis reflexa, Gray. Cardium striatulum, Sowerby. Venericardia australis, Quoy. Michaud. Lucina divaricata, Lamark. Mysia zealandica, Gray. " globularis, Lamark. Pythina stowei, Hutton. Solemya australis, Lamark. Mytilus smaragdinus, Chemnitz. " ater, Zelebor. Crenella discors, Lamark. Modiola albicostata, Lamark. Lithodomus truncatus, Gray. Pinna zealandica, Gray. Pectunculus laticostatus, Quoy. " striatularis, Lamark. Nucula margaritacea, Lamark. " consobrina, Adams and Angas. Pecten zelandiœ, Gray. Vola laticostatus, Gray. Anomia, sp. Ostrea, sp. " mordax, Gould. V. Brachiopoda. Terebratella rubicunda, Solander.