A CASE OF ABNORMAL PLUMAGE. 29 1 



and others, including the writer. The barb itself may be broken 

 near the distal end according to Meves and Chapman. In these 

 instances, the breaking is believed to occur some weeks or 

 months after the feather was fully de- 



dst. 



veloped. In the case of these abnor- 

 mal feathers, however, nothing is 



known as to the time when the bar- 

 bules may have been broken, but the 



: 



- 



/\ 

 condition was observed only a few 



days after the feathers had emerged 



from the sheath enclpsing the feather brbl P rx, irti.dst. 



germ. 



Tlic Body Coverts. The most strik- 

 ing type of abnormality appeared in 

 the body coverts, and it is very differ- 

 ent from what was seen in the remiges FlG 3 Dorsal view of a por . 



and rectrices. tion of a barb bearing barbule stubs 



A normal body covert of the juve- from the left side of th f shaft in 



,. , . . , . the region represented in Figure 



nal plumage from another hybrid is 2 ( ?4 ^ ^., distal bar . 



shown in Fig. 4. The downy por- bules; brbl. p>-x., proximal bar- 



tion, /. c., the part where the barbules bules ; *'> distal end of portion 



, .,, , , of barb figured; prx. . proximal 



are long and with rudimentary bar- 

 end of portion ot barb hgured. 



bicels is represented diagrammatically. 



The barbs or portions of barbs bearing shorter barbules with 

 hooked barbicels usually, in the distal row, are indicated semi- 

 diagrammatically by lines radiating from the shaft, but no attempt 

 has been made to represent the true number of the barbules. 

 It will be seen that by far the larger portion of the vane of 

 such a feather is downy. 



An abnormal feather from a corresponding region on the back 

 of the bird under consideration is represented in Fig. 5. Al- 

 most the whole feather appears downy and there is a strange 

 tassel-like appendage to the distal end of what may be called the 

 main body of the feather. With the aid of a microscope, one 

 finds that two or more of the more distal barbs are fused at their 

 distal ends into a horny, unpigmented, irregularly-shaped cylinder 

 (Fig. 5, rj'/.), which branches at its distal end into several downy 

 barbs and a median shaft that itself bears barbs on either side in 



