ATTEMPT TO DEDUCE VERTEBRATE EYES FROM THE SKIN. 343 
An Attempt to deduce the Vertebrate Eyes 
from the Skin. 
By 
H. M. Bernard, M.A.Cantab., F.L.S. 
With Plate 22. 
In the February issue of the ‘ Annals and Magazine of 
Natural History’ I published an outline sketch of a new 
theory of vision. It was suggested that eyes arose as local 
modifications of tissue induced by the excessive crowding of 
pigmented granules at spots most frequently and brilliantly 
illuminated, and that this crowding of the pigmented granules 
might be made to explain both the origin of the eye as a 
structure and its functions as an organ. I now propose, as 
time and opportunity allow, to compare a few eyes with the 
tissues out of which they have, or according to the theory they 
should have. arisen, in order to ascertain how far such com- 
parisons support the theory. 
I take the Vertebrata first, not only because the general 
facts of the structure and development of the eyes in this class 
are most widely known, but because of the paramount interest 
attaching to any questions relating to our own highest sense. 
Now, according to the theory alluded to, eyes must have 
developed out of that tissue in which, under the action of 
light, pigment accumulates. That tissue is the skin; hence 
the eyes in the Vertebrata must have arisen as modifications of 
the skin. There are two kinds of eyes in the Vertebrata; the 
more or less vestigial ‘ pineal” eye, and the Vertebrate eye 
