ATTEMPT TO DEDUCE VERTEBRATE EYES FROM THE SKIN. 307 
eye is, however, so immature that this latter is not yet a 
clear slimy fluid, but a dense mass of fine granules, quite 
referable, as far as microscopic appearances go, to pigment 
granules only partially dissolved and clarified.! 
This, in brief, is the way in which it is possible to conceive 
that the eye might have been developed directly from the 
skin, as our theory demands. That it actually has developed 
in this way is perhaps difficult to prove in face of the very 
different history suggested by its embryology ; still, when the 
evidence is summed up, it appears to be of considerable 
weight. 
I claim, for instance, that by this method of deriving the 
eye, the arrangement and character of all the more important 
tissues are fully accounted for.” 
As examples I may draw attention to the following points : 
1. The pigmented epithelium is not an ordinary epithelium, 
but rather a close layer of chromatophores, some of which 
are large ten-sided cells with two nuclei,’ which latter feature 
is not infrequent in chromatophores. 
2. The presence of the stellate chromatophores in the 
choroid would be a vestige of the dense chromatophorai layer 
that seems to have been very generally present in the cutis of 
many pre-mammalian Vertebrates. 
3. The fibrous connection between the front surface of the 
iris and the cornea, specially pronounced as the ligamentum 
annulare of fishes, might well be the remains of the neck of 
the assumed invagination. It is attached to the iris and not 
to the lens, which is of significance for this method of deducing 
the eye from the skin. 
4, The difference between the vitreous and aqueous humours 
1 I propose to enlarge on this subject in an illustrated paper dealing 
specially with skins and pigments. 
? I have omitted all mention of the sclerotic because I believe its develop- 
ment was concerned with that of the conjunctival folds, and of the specialised 
muscles for the movement of the eye, which latter did not come within the 
range of the inquiry. 
3 Boden and Sprawson, ‘ Quart. Journ. Mier. Sci.,’ vol. xxxiii. 
VOL. 39, PART 3.—NEW SER. AA 
