That each of these Pearls or _Hemispheres_ is a perfect eye, I think we need not doubt, if we consider onely the outside or figure of any one of them, for they being each of them cover’d with a transparent protuberant _Cornea_, and containing a liquor within them, resembling the watry or glassie humours of the eye, must necessarily refract all the parallel Rays that fall on them out of the air, into a point not farr distant within them, where (in all probability) the _Retina_ of the eye is placed, and that opacous, dark, and mucous inward coat that (I formerly shew’d) I found to subtend the concave part of the cluster is very likely to be that _tunicle_ or coat, it appearing through the _Microscope_ to be plac’d a little more than a Diameter of those Pearls below or within the _tunica cornea_. And if so, then is there in all probability, a little Picture or Image of the objects without, painted or made at the bottom of the _Retina_ against every one of those Pearls, so that there are as many impressions on the _Retina_ or opacous skin, as there are Pearls or _Hemispheres_ on the cluster. But because it is impossible for any protuberant surface whatsoever, whether _sphærial_ or other, so to refract the Rays that come from farr remote _lateral_ points of any Object as to collect them again, and unite them each in a distinct point, and that onely those Rays which come from some point that lies in the _Axis_ of the Figure produc’d, are so accurately refracted to one and the same point again, and that the _lateral_ Rays, the further they are remov’d, the more imperfect is their refracted confluence; It follows therefore, that onely the Picture of those parts of the external objects that lie in, or neer, the _Axis_ of each _Hemisphere_, are discernably painted or made on the _Retina_ of each _Hemisphere_, and that therefore each of them can distinctly sensate or see onely those parts which are very neer perpendicularly oppos’d to it, or lie in or neer its optick _Axis_. Now, though there may be by each of these eye-pearls, a representation to the Animal of a whole _Hemisphere_ in the same manner as in a man’s eye there is a picture or sensation in the _Retina_ of all the objects lying almost in an _Hemisphere_; yet, as in a man’s eye also, there are but some very few points which liyng in, or neer, the optick _Axis_ are distinctly discern’d: So there may be multitudes of Pictures made of an Object in the several Pearls, and yet but one, or some very few that are distinct; The representation of any object that is made in any other Pearl, but that which is directly, or very neer directly, oppos’d, being altogether confus’d and unable to produce a distinct vision.