The texture of it is such, that I have not yet met with any other body in the world that has the like, but onely one of a larger sort of Sponge (which is preserv’d in the _Museum Harveanum_ belonging to the most Illustrious and most learned Society of the _Physicians_ of _London_) which is of a horney, or rather of a _petrify’d_ substance. And of this indeed, the texture and make is exactly the same with common Sponges, but onely that both the holes and the _fibres_, or texture of it is exceedingly much bigger, for some of the holes were above an Inch and half over, and the _fibres_ and _texture_ of it was bigg enough to be distinguished easily with ones eye, but conspicuously with an ordinary single _Microscope_. And these indeed, seem’d to have been the habitation of some Animal; and examining _Aristotle_, I find a very consonant account hereunto, namely, that he had known a certain little Animal, call’d _Pinnothera_, like a Spider, to be bred in those caverns of a Sponge, from within which, by opening and closing those holes, he insnares and catches the little Fishes; and in another place he says, That ’tis very confidently reported, that there are certain Moths or Worms that reside in the cavities of a Sponge, and are there nourished: Notwithstanding all which Histories, I think it well worth the enquiring into the History and nature of a Sponge, it seeming to promise some information of the Vessels in Animal substances, which (by reason of the solidity of the interserted flesh that is not easily remov’d, without destroying also those interspers’d Vessels) are hitherto undiscover’d; whereas here in a Sponge, the _Parenchyma_, it seems, is but a kind of mucous gelly, which is very easily and clearly wash’d away. The reason that makes me imagine, that there may probably be some such texture in Animal substances, is, that examining the texture of the filaments of tann’d Leather, I find it to be much of the same nature and strength of a Sponge; and with my _Microscope_, I have observ’d many such joints and knobs, as I have described in Sponges, the _fibres_ also in the hollow of several sorts of Bones, after the Marrow has been remov’d, I have found somewhat to resemble this texture, though, I confess, I never yet found any texture exactly the same, nor any for curiosity comparable to it. The filaments of it are much smaller then those of Silk, and through the _Microscope_ appear very neer as transparent, nay, some parts of them I have observ’d much more.