Observ. XXXIII.Of the Scales of a Soal, and other Fishes.
HAving hinted somewhat of the skin and covering of terrestrial Animals, I shall next add an Observation I made on the skin and Scales of a Soal, a small Fish, commonly enough known; and here in Fishes, as well as other Animals, Nature follows its usual method, framing all parts so, as that they are both usefull and ornamental in all its composures, mingling utile and dulce together; and both these designs it seems to follow, though our unassisted senses are not able to peceive them: This is not onely manifest in the covering of this Fish[errata 1] but in multitudes of others, which it would be too long to enumerate, witness particularly that small Sand Shell, which I mention'd in the XI. Observation, and infinite other small Shells and Scales, divers of which I have view'd. This skin I view'd, was flead from a pretty large Soal, and then expanded and dry'd, the inside of it, when dry, to the naked eye, look'd very like a piece of Canvass, but the Microscope discover'd that texture to be nothing else, but the inner ends of those curious Scolop'd Scales I, I, I, in the second Figure of the XXI. Scheme, namely, the part of G G G G (of the larger representation of a single Scale, in the first Figure of the same Scheme) which on the back side, through an ordinary single Magnifying Glass, look'd not unlike the Tyles on an house.
The outside of it, to the naked eye, exhibited nothing more of ornament, save the usual order of ranging the Scales into a triagonal form, onely the edges seem'd a little to shine, the finger being rubb'd from the tail-wards towards the head, the Scales seem'd to stay and raze it; But through an ordinary Magnifying glass, it exhibited a most curiously carved and adorned surface, such as is visible in the second Figure, each of those (formerly almost imperceptible) Scales appearing much of the shape I, I, I, that is, they were round, and protuberant, and somewhat shap'd like a Scolop, the whole Scale being creas'd with curiously wav'd and indented ridges, with proportionable furrows between; each of which was terminated with a very sharp transparent bony substance, which, like so many small Turnpikes, seem'd to arm the edges.
The back part K K K was the skin into which each of these Scales were very deeply fix'd, in the curious regular order, visible in the second
Schem. XXI. Figure. The length and shape of the part of the Scale which was buried by the skin, is evidenced by the first Figure; which is the representation of one of them pluck'd out and view'd through a good Microscope, namely, the part L F G G F L, wherein is also more plainly to be seen, the manner of carving of the scolopt part of every particular Scale, how each ridge or barr E E E is alternately hollowed or engraven, and how every gutter between them is terminated with very transparent and hard pointed spikes, and how every other of these, as A A A A, are much longer then the interjacent ones, D D D.
The texture or form also of the hidden part appears, namely, the middle part, G G G, seems to consist of a great number of small quills or pipes, by which, perhaps, the whole may be nourished; and the side parts F F consist of a more fibrous texture, though indeed the whole Scale seem'd to be of a very tough gristly substance like the larger Scales of other Fishes.
The Scales of the skin of a Dog-fish (which is us'd by such as work in Wood, for the smoothing of their work, and consists plainly enough to the naked eye, of a great number off small horny points) through the Microscope appear'd each of them curiously ridg'd, and very neatly carved; and indeed, you can hardly look on the scales of any Fish, but you may discover abundance of curiosity and beautifying; and not only in these Fishes, but in the shells and crusts or armour of most sorts of Marine Animals so invested.
Errata