PLATE LXXXVII 



EVOLUTION OF THE EYES ON A PEACOCK'S TRAIN 



The beginnings of these marvellous ocelli must have been first visible on the plumage of some far 

 distant ancestor of all peafowl, perhaps a hundred thousand years ago. Yet to-day in the train of an 

 individual bird we may clearly trace their development of pattern and pigment. 



Beneath one of the pale, terminal cross bands which we find on the smaller feathers, there appears (on 

 an adjoining feather somewhat farther down the train) a blur of chestnut, which draws gradually together, 

 and, concentrating, reaches up the shaft into a slowly expanding, terminal area of green. The chestnut is 

 soon cut off at the bottom by the surrounding green zone, and now shows as a small monochrome fan of 

 warm colour. In the heart of this a tiny speck of metallic blue develops and widens, and within this, in 

 turn, a dot of black. Here we have the eye in its simplest form— shall we imagine that it corresponds to 

 that which peafowl displayed ten thousand years ago ? The change to the fully perfected eye is chiefly 

 by enlargement, by a slight bilobing of the pupil, and by the addition of lavender, golden, copper and 

 emerald frames. 



