t 
consists of an imperfect or deficient development of the barbules; also 
any single barb may have one or several defective places in it, depending 
upon the closeness of the bars to one another. 
As shown in the sketch (Fig. 2), the barbules in the region of the 
defects are shorter and do not project from the barb to the same degree as 
elsewhere. In strongly marked examples even the barbs are not separated 
from one another, and the barbules are altogether absent, as in Fig. 3. 
SSS 
liek, YD, 
A portion of the shaft of a feather with three barbs attached to one side. each barb 
showing six barring intervals which correspond with the same number of complete bars on 
the entire plume. Where each bar occurs the barbules are either altogether absent or only 
partly developed, and the barb itself may be slightly kinked. 
In addition, the barbs themselves are usually slightly bent or kinked, 
and if the fault extend across the shaft, the latter is deeply indented in an 
angular manner. The entire appearance suggests that at the bar the feather 
has been subjected to a compression or shrinkage while it was still soft and 
an process of development, the pressure preventing the proper formation 
of the flue and shaft, and later their proper unfolding as the feather 
ripened. 
It is also of some importance to note that the vertical height of the 
individual bar varies but little; and further they are never broad, but 
always very narrow, rarely exceeding a sixteenth of an inch across. The 
reason for this will appear later. 
IMKES Sy 
A portion of the shaft of a feather with four barbs attached.to one side. The barbs 
are bound to one another where the deep bar occurs, On each barb two other barring 
places are shown beyond that at which they are united. 
That the bar is a place of weakness in the flue is seen by the readiness 
‘with which breakages take place wherever the bars oecur, when if 
numerous the breakages render the feather almost valueless. (Figs. I, 4, 
and 5.) 
The number of bars on different plumes varies. Sometimes only a 
few will be present, and then more especially towards the free end, while 
at other times they occur at more or less regular intervals along nearly 
the entire feather. On some plumes they are so arranged as to suggest an 
alternating regularity, that is, an arrangement at equal distances apart. 
