60 Objects for the Microscope. 



Last of all that I shall mention, as paper would fail me 

 if I noticed all our spider friends, is the Diving Spider of 

 our aquariums (Argyroneta), common near London, rare in 

 many parts of England : which has been taught to make a 

 diving-bell for the work which God has appointed her. The 

 water-world requires its avengers to keep down the fast- 

 multiplying creatures therein, and the Argyroneta aquatica 

 is one of them. True her gill-like lungs enable her to 

 breathe under water; but still she requires more oxygen than 

 it affords, and comes up about four times an hour for a 

 supply of air. This she conveys to a silken house she has 

 previously spun amidst the weeds in still water, and which 

 we see shining like a little globe of silver ; the Spider half 

 inside, her breathing organs immersed in the air, and her 

 head outside, watching for a tiny Beetle or a little Cyclops. 

 For a more detailed account of the Water Spider, see 

 ' Kirby and Spence's Entomology/ or the smaller work called 

 ' Insect Architecture.' I only mention these facts to prove 

 the reasonableness of the high position the Arachnida hold, 

 and the unreasonableness of the neglect and dislike they 

 often meet with. I bring them forward because the whole 

 Spider is to be purchased beautifully prepared, and its 

 external parts may thus be studied ; also because the comb 

 of the foot is in every collection, and it is more interesting 

 when we have some further knowledge of the body to 

 which it once belonged. 



The Spider's legs have a different formation from those 

 of insects. Each has seven joints ; the two upper ones 

 form a kind of haunch ; the next is the femur ; the fourth 

 and the fifth are tibiae ; the first or second according to 

 the species, much the longest ; the last two are the tarsi, 

 less distinct than those of insects, but remarkably furnished 

 with toothed claws called the combs. In our Garden 

 Spider, the Epeira, there are no less than five of these 

 combs, besides three upper and untoothed claws, to each 

 foot ; also a strong moveable spine or hook at the joint of 

 each tarsus. 



