TRANSACTIONS OF THE NEW ZEALAND INSTITUTE, 1899. I. ZOOLOGY. ART. I. Zoological Results of Trawling Trials off the Coast of Otago. By Professor BENHAM, D.Sc., M.A., F.Z.S. [Read before the Otago Institute, 11th July, 1899.] EARLY in the year the Otago Harbour Board lent their tug, the s.s. "Plucky," for the use of a party of gentlemen, some interested in commercially valuable products of the sea, others in scientifically interesting inhabitants. The opportunity of seeing an otter-trawl at work in comparatively deep water, and of collecting zoological material brought up by it, was thus afforded to and seized upon by me. There were two expeditions made-one in the day-time, on the 27th February, when the boat went northwards for a distance of about three miles, and trawled in about 10 to 20 fathoms; the second was a nocturnal trip-4th to 5th March-when the boat went much further eastwards and southwards, trawling in water varying from 10 to 30 fathoms. It appears to be of interest to put on record the more important animals collected by us, since new localities for known species are established, and a number of species that appear to be new were obtained. It must be mentioned that we had no small "dredge" for collecting. It is true I took a surface-net with me, but I am not concerned at present with the plankton. The following animals were brought up in the wide-meshed otter-trawl, and represent only a tithe or a hundredth part of the material awaiting capture immediately outside the harbour; and in the near future I hope to have the opportunity of going over the sandy banks here with a small-meshed dredge. The following is a list of the more interesting forms. It is to be borne in mind that shells are mentioned only when they contained the living animal :: Astrogonium abnormale: Several. Gnathaster, sp.: One. Asterias, sp. (fine, scarlet). Asterina regularis: In abundance. Holothurian: A fine species, about 10 in. or 12 in. long. ANNELIDA. Branchellion, on Raia, sp. Pontobdella. Phyllodocids. Nereids. Polynoids, &c. Also a number of sea-anemones, of which one was especially handsomea large bright-red column, with white tubercles in rows; also a number of smaller anemones, hydroids, and sponges, as well as compound Ascidians, which I have not as yet attempted to identify. This is not a very great collection, nor widely representative, but it presents instances of bionomics that are of some interest. An interesting instance of commensalism came into view in smashing the shells inhabited by the hermit crab-chiefly Struthiolaria and Fusus shells. In the upper part of the shell, above or at the side of the Pagurid's abdomen, was found, in several instances, an Annelid, closely allied to the common Nereis that occurs in mud or sand below stones along the coast. This worm, however, is stouter and more brightly coloured than the shell-worm. It is banded alternately reddish-brown and white, and is remarkable in that the first pectoral segment is produced forwards round the head as a free collar-like flap. It is an entirely new species, and may possibly be the type of a new genus-new not only to New Zealand, but to science. As I have not yet fully examined it I withhold its name, since I cannot here give a detailed description of it. I found both males and females. In the latter the green eggs within partially killed the brown colour of the bodywall. The males and females occurred isolated: I did not find more than one worm in each shell. Each hermit crab was accompanied by a second messmate in the shape of a small shrimp-like animal, which Mr. G. M. Thomson has been good enough to name for me: it is Lilljeborgia haswelli. This little amphipod is peculiarly colouredthe head end is red, the tail half is white. It occupied the topmost whorl of the shell; and I do not remember seeing more than one at a time. Hermit crabs have long been known to be accompanied by a Nereid, but I believe the occurrence of an amphipod together with the other two is a novelty. The crabs afforded excellent examples of "protection," for the carapace was entirely concealed by foreign growthsponges, hydroids, &c.—and even the exposed parts of some of the appendages bore their share. A brief reference to a beautiful Doris may be added. We obtained six or seven large violet Dorids, measuring from 4 in. to 7 in. long during life, and about 3 in. broad and about 1 in. high. The most remarkable feature, apart from the size and colour, lies in the closely set, rounded, flattened papillæ, of various sizes, large and small, into which the skin of the entire dorsal and lateral surfaces is raised up, some of the papillæ measuring nearly in. across. This is not unlike Abraham's D. wellingtonensis, but there is nothing in his description that enables me to identify this find with his much smaller Dorid. |