![Thumbnail: [Volume 10, 1877 page 299]](/journals/rsnz/images/rsnz_10/thumbnails/rsnz_10_00_0344_0299_ac_02.gif)
Art. XLI.—Notes on a Marine Spider found at Cape Campbell.
[Read before the Wellington Philosophical Society, 24th February, 1877.]
My attention was first directed to our numerous spiders by an interesting account of the trap-door spider by Mr. R. Gillies.* After having read the paper above quoted, I began to collect specimens of such spiders as were to be found about Cape Campbell, more with the hope of finding some of the trap-door variety than of discovering a new one.
Soon after this one of my boys told me that, while playing on the cape at low water, he had seen a spider in one of the tidal pools. Never having heard of the existence of a sea-spider, I thought he must have made a mistake; and I was more disposed to think so when I began to consider that, even if a spider could live in the sea, he could not do so without food, and he would not find any flies or beetles there. I may here remark, that up to the present time I have not been able to discover what these spiders do live on. But to return to my boy's discovery.
On going to see what it was, I found a veritable spider quite at home under the water, and having a nest in an old Lithodomus hole, of which the rocks about here are full. All the spiders of this kind which we have found have had nests in these holes, and always under water at all times of the tide. Over the mouth of the hole the spider spins a close web, which
[Footnote] * Trans. N.Z. Inst., VIII., Art. XXXI.
![Thumbnail: [Volume 10, 1877 page 300]](/journals/rsnz/images/rsnz_10/thumbnails/rsnz_10_00_0345_0300_ac_02.gif)
when finished looks like a thin film of isinglass, and is water-proof; and behind this film is the nest and egg-sac, which last is of various shapes and contains a large number of eggs.
When the spider is disturbed it goes to the bottom of the pool, and if a small stick or straw is extended to it it at once gets ready for a fight, advancing its long and powerful mandibles for that purpose. The strength and formidable nature of these is well shown in the illustration which accompanies this paper, and for which I am indebted to Mr. A. Hamilton, who is also a member of the Society.
When a small fish is placed in a bottle of water with one of these spiders, the latter will attack at once, driving its long sharp falces into the fish near the head and killing it instantly. Each spider seems to live in solitary state, and it is, I believe, an exceedingly pugnacious little animal; but I have not had the time or opportunity for studying its habits closely, and regret not being able to give more information respecting it.
Each spider seems to be of two colours, the cephalo-thorax being a red-brown and the abdomen of a greenish hue, these colours becoming more distinct when the spider is placed in spirits.
[Note by Dr. Hector.—This spider is allied to the genus Argyronetra, of which A. aquatica, the water-spider of Britain, is a well-known species. It differs from the generic characters given for that in the position of the ocelli, which are of equal size, eight in number, and arranged in divergent pairs. I can find no record of a species of water-spider inhabiting the sea, and, as Mr. Robson points out, it is difficult to conceive what can be its prey, unless it be insects that accidentally float on the surface. The water-spider builds its nest and hatches its young under water, constructing a diving-bell which it keeps supplied with air by bubbles entangled by the hairs which cover the abdomen and enclosed by the legs. For this species I propose the name Argyronetra marina.]