Fourthly, that the rest of the capacity of the clusters was in some, as in Dragon Flies, &c. hollow, or empty; in others fill’d with some kind of substance; in blue Flies, with a reddish musculous substance, with fibres tending from the center or bottom outwards; and divers other, with various and differing kinds of substances.

That this curious contrivance is the organ of sight to all those various Crustaceous Animals, which are furnish’d with it, I think we need not doubt, if we consider but the several congruities it has with the eyes of greater creatures.

As first, that it is furnish’d with a Cornea, with a transparent humour, and with a uvea or retina, that the Figure of each of the small Hemispheres are very Spherical, exactly polish’d, and most vivid, lively and plump, when the Animal is living, as in greater Animals, and in like manner dull, flaccid, and irregular, or shrunk, when the Animal is dead.

Next, that those creatures that are furnish’d with it, have no other organs that have any resemblance to the known eyes of other creatures.

Thirdly, that those which they call the eyes of Crabs, Lobsters, Shrimps, and the like, and are really so, are Hemispher’d, almost in the same manner as these of Flies are.  And that they really are so, I have very often try’d, by cutting off these little movable knobs, and putting the creature again into the water, that it would swim to and fro, and move up and down as well as before, but would often hit it self against the rocks or stones; and though I put my hand just before its head, it would not at all start or fly back till I touch’d it, whereas whil’st those were remaining, it would start back, and avoid my hand or a stick at a good distance before it touch’d it.  And if in crustaceous Sea-animals, then it seems very probable also, that these knobs are the eyes in crustaceous Insects, which are also of the same kind, onely in a higher and more active Element; this the conformity or congruity of many other parts common to either of them, will strongly argue, their crustaceous armour, their number of leggs, which are six, beside the two great claws, which answer to the wings in Insects; and in all kind of Spiders, as also in many other Insects that want wings, we shall find the compleat number of them, and not onely the number, but the very shape, figure, joints, and claws of Lobsters and Crabs, as is evident in Scorpions and Spiders, as is visible in the second Figure of the 31. Scheme, and in the little Mite-worm, which I call a Land-crab, describ’d in the second Figure of the 33. Scheme, but in their manner of generation being oviparous, &c.  And it were very worthy observation, whether there be not some kinds of transformation and metamorphosis in the several states of crustaceous water-animals, as there is in several sorts of Insects; for if such could be met with, the progress of the variations would be much more conspicuous in those larger Animals, then they can be in any kind of Insects our colder Climate affords.