Plate II., Fig. 1, is the upper side of a portion of a Barb cut from a Primary 

 feather of a Swan, enlarged 85 times through the microscope. The broad black 

 band is the barb from which stand up the distal barbules, among which many 

 hooks (hamuli) are visible. The chief feature is the graceful curve of the 

 barbules and their more or less open appearance. 



Plate 11., Fig. 2, is the lower side of a portion of a Barb cut from a Golden 

 Eagle Primary, photographed from the back with a magnification of 120 times. 



The broad somewhat confused bek is the barb. The lighter irregular belt 

 just above it is the light shining through the base of the distal barbules. At the 

 bottom of the print the commencement of the proximal barbules may be seen. 

 In contrast to the swan barbules it will be noticed that, instead of fine delicate 

 structure, the golden eagle barbules are broad and dense. In the shadow of the 

 barbules may be seen certain curved patches of light. These are hamuli, but the 

 photograph was not taken with the object of defining them specially, as when 

 photographing them through the microscope it is not possible to focus sharply 

 objects in different planes. 



Plate II., Fig. 3, is the upper side of a portion of a Barb taken from an Owl 

 Primary, with a magnification of 60 times. The broad belt at the base is the 

 barb from which spring the distal barbules. In Plate II., Fig. 1, it may be seen 

 that the barbules extend a comparatively short distance beyond the hook region, 

 while in the case of the owl they extend to such a great distance beyond the 

 hook region that each barbule not only hooks on to the proximal barbules of the 

 neighbouring barb but overlaps the surface of several barbs. This long extension 

 of the distal barbules seems to be plumulaceous in its construction and thus gives 

 the soft fluffy character to the plumage of the owl. 



