60 The Bird 
verge more and more, until two distinct longitudinal 
lines are formed, with traces of a third near the quill. 
A smaller feather from the same wing is marked with 
spots which are nearly circular and which show faint 
traces of encircling bands of white pointing toward a 
still more elaborate system of decoration. 
ke | 
fic. 39.—Evolution of a colour pattern upon two feathers of a ulturine Guirea- 
fowl; a stripe breaking up into dots, these forming cross-vars, and on the 
second feather a regular series of dots encircled with white. 
It is interesting to conjecture in which direction the 
decoration of feathers is proceeding. In the case of the 
guinea-fowl, are the spots converging into lines or are 
the lines the more ancient, and for some reason grad- 
ually splitting up into smaller divisions? This is hard to 
decipher, and if we look at the rest of the guinea-fowl’s 
body, the matter becomes only the more complicated. 
