A STUDY OF FUNDAMENTAL BARS IN FEATHERS. l6/ 



a bird can encounter and endure. In types one and two the 

 barbs and shaft are often bent or kinked in the abnormal 



region. 



The third type of defect is something very much less conspicu- 

 ous than either of the two types already considered. It could 

 not be represented in the drawing. It is a very minute depres- 

 sion extending across the upper and dorsal surface of the feather. 

 It is not always easy, however, to determine that it is a depres- 

 sion at all. It often seems a line, or simply the point of union 

 of a distal with a proximal part of the feather-vane. This line 

 crosses a series of barbs making with them a right angle as did 

 the defective area of type one. These lines or depressions are 

 usually so inconspicuous that even close observation may not re- 

 veal them. Yet they exist and can be demonstrated in all feathers, 

 and at any level throughout the length of the feather. 



The existence of these depressions as normal occurrences in 

 the feather is apparently nowhere mentioned in the literature. 

 Certainly their significance has not been made known. As may 

 be inferred from my classification of them, I have 

 found them to bear a close relation to the defective 

 feather areas. These lines which are thoroughly 

 characteristic of feathers are properly classified among 

 feather defects, for, it is always at these lines that the 

 defects like those of types one and four appear and, 

 moreover, they show all possible gradations into types 

 one and four. I shall hereafter speak of defects of 

 this type as defective lines, or depressions ; those of 

 type one as defective areas ; those of type four as con- FIG. 2. En- 



Strictions. tire feather- 



It is those feather-vanes which are made up of a germ rora 



Car din arts 



series of deep depressions or constrictions that show v i r<r j n i am{S 

 the defects of type four. I shall say nothing here showing con- 

 of the conditions represented in this type, but per- strict ions. 



, r i r i (Actual length 



haps an idea can be had from the feather germ shown ^ mm . 

 in Fig. 2. 



Of type five, I have seen but a single example. In this the 

 defect extends vertically or the long way of the feather. The 

 barbs of one half of the vane have their distal portions broken 



