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Transactions. — Zoology. 



when finished looks hke 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, di-iving its long 

 sharj) 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. Eobson 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.] 



