3o8 TADPOLES OF THE SEA 



graduations (Plate XII), commencing with a small 

 patch of blueish colour, from which they lead on with 

 increase of size to others with a first appearance of an 

 incomplete eye and of some metallic green iridescence, 

 and then by larger and more strongly coloured examples 

 up to the great feathers with the sharply marked 

 eye-spot and ring of colour and shad6 and the large 

 green iridescent row of pieces like the leaflets of a 

 palm-leaf, equal in size and brilliance, on each side 

 of the shaft. But at the sides of the group of splendid 

 eyed feathers we find another series of gradations. These 

 are a " degenerating," or " simplified " series (Plate 

 XIII); whereas those just described are the "pro- 

 gressive series," leading from the ordinary body feathers 

 upwards to the wonderful eyed feathers. The simplified 

 lateral feathers are as long as the big eyed feathers ; byit 

 as we pass from the middle towards the sides of the 

 radiant expanse of the displayed " train " or " tail " these 

 feathers show a gradually increasing one-sidedness. The 

 eye-spot itself of the laterally placed feathers becomes 

 one-sided, and when we pass along the series towards the 

 side we find that it disappears entirely ! The iridescent 

 green colour is maintained in all its glory, but the leaflets 

 of the plume (the " rami " or " barbs " as they are called) 

 dwindle in size on one side of the shaft, and become fewer, 

 but very large, and free from adhesion to one another, on 

 the other side. The final stage shown by the outermost 

 feathers of the group is that of a long shaft, with nothing 

 on it but a few large, separate, splendidly green " rami," 



Plate XIII. — Photographs of a series of large "tail coverts" of the peacock's 

 " train," showing the increasing one-sidedness as one proceeds from 

 the central to the outer or side-feathers and the gradual loss of the 

 " eye " with the retention of the great length and metallic iridescence by 

 even the most one-sided and simplified feathers — those on the right 

 hand side of the lower row. From a preparation placed by Sir William 

 Flower in the central hall of the Natural History Museum. 



