Micrographia, by Robert Hooke

Observ. xlvii. Of the Shepherd Spider, or long legg'd Spider.

The Carter, Shepherd Spider, or long-legg'd Spider, has, for two particularities, very few similar creatures that I have met with, the first, which is discoverable onely by the Microscope, and is in Schem. 31.
Fig. 1. & 2.
the first and second Figures of the 31. Scheme, plainly describ'd, is the curious contrivance of his eyes, of which (differing from most other Spiders) he has onely two, and those plac'd upon the top of a small pillar or hillock, rising out of the middle of the top of its back, or rather the crown of its head, for they were fix'd on the very top of this pillar (which is about the heighth of one of the transverse Diameters of the eye, and look'd on in another posture, appear'd much of the shape, BCD.) The two eyes, BB, were placed back to back, with the transparent parts, or the pupils, looking towards either side, but somewhat more forward then backwards. C was the column or neck on which they stood, and D the crown of the head out of which that neck sprung.

These eyes, to appearance, seem'd to be of the very same structure with that of larger binocular creatures, seeming to have a very smooth and very protuberant Cornea, and in the midst of it to have a very black pupil, incompassed about with a kind of grey Iris, as appears by the Figure; whether it were able to move these eyes to and fro, I have not observ'd, but 'tis not very likely he should, the pillar or neck C, seeming to be cover'd and stiffen'd with a crusty shell; but Nature, in probability, has supply'd that defect, by making the Cornea so very protuberant, and setting it so cleer above the shadowing or obstructing of its prospect by the body, that 'tis likely each eye may perceive, though not see distinctly, almost a Hemisphere, whence having so small and round a body plac'd upon such long leggs, it is quickly able so to wind, and turn it, as to see any thing distinct. This creature, as do all other Spiders I have yet examin'd, does very much differ from most other Insects in the Figure of its eyes; for I cannot, with my best Microscope, discover its eyes to be any ways knobb'd or pearl'd like those of other Insects.

The second Peculiarity which is obvious to the eye, is also very remarkable, and that is the prodigious length of its leggs, in proportion to its small round body, each legg of this I drew, being above sixteen times the length of its whole body, and there are some which have them yet longer, and others that seem of the same kind, that have them a great deal shorter; the eight leggs are each of them jointed, just like those of a Crab, but every of the parts are spun out prodigiously longer in proportion; each of these leggs are terminated in a small case or shell, shap'd almost like that of a Musle-shell, as is evident in the third Schem. 31.
Fig. 3.
Figure of the same Scheme (that represents the appearance ot the under part or belly of the creature) by the shape of the protuberant conical body, IIII, &c. These are as 'twere plac'd or fasten'd on to the protuberant body of the Insect, which is to be suppos'd very high at M, making a kind of blunt cone whereof M is to be suppos'd the Apex, about which greater cone of the body, the smaller cones of the leggs are plac'd, each of them almost reaching to the top in so admirable a manner, as does not a little manifest the wisdom of Nature in the contrivance; for these long Leavers (as I may so call them) of the legs, having not the advantage of a long end on the other side of the hypomochlion or centers on which the parts of the leggs move, must necessarily require a vast strength to move them, and keep the body ballanc'd and suspended, in so much, that if we should suppose a man's body suspended by such a contrivance, an hundred and fifty times the strength of a man would not keep the body from falling on the breast. To supply therefore each of these leggs with its proper strength, Nature has allow'd to each a large Chest or Cell, in which is included a very large and strong Muscle, and thereby this little Animal is not onely able to suspend its body upon less then these eight, but to move it very swiftly over the tops of grass and leaves.

Nor are these eight leggs so prodigiously long, but the ninth, and tenth, which are the two claws, KK, are as short, and serve in steed of a proboscis, for those seem'd very little longer then his mouth; each of them had three parts, but very short, the joints KK, which represented the third, being longer then both the other. This creature, seems (which I have several times with pleasure observ'd) to throw its body upon the prey, insteed of its hands, not unlike a hunting Spider, which leaps like a Cat at a Mouse. The whole Fabrick was a very pretty one, and could I have dissected it, I doubt not but I should have found as many singularities within it as without, perhaps, for the most part, not unlike the parts of a Crab, which this little creature does in many things, very much resemble; the curiosity of whose contrivance, I have in another place examin'd. I omit the description of the horns, AA, of the mouth, LL, which seem'd like that of a Crab; the speckledness of his shell, which proceeded from a kind of feathers or hairs, and the hairiness of his leggs, his large thorax and little belly, and the like, they being manifested by the Figure; and shall onely take notice that the three parts of the body, namely, the head, breast, and belly, are in this creature strangely confus'd, so that 'tis difficult to determine which is which, as they are also in a Crab; and indeed, this seems to be nothing else, but an Air-crab, being made more light and nimble, proportionable to the medium wherin it resides; and as Air seems to have but one thousandth part of the body of Water, so does this Spider seem not to be a thousandth part of the bulk of a Crab.

scheme31

http://ebooks.adelaide.edu.au/h/hooke/robert/micrographia/observ47.html

Last updated Monday, March 17, 2014 at 16:42