1914] Chandler: Feathers of Circus hudsonius 341 



decreasing at the base, and then very slowly decreasing all the 

 way to the tip. As is the case throughout the plumage, the 

 distal barbules outnumber the proximals. Near the middle of a 

 barb taken from the middle portion of the inner vane there are 

 approximately thirty-seven distal barbules per millimeter and 

 twenty proximals. There is very little variation in this regard 

 in barbs taken nearer the base or the tip of the feather, though 

 there is a slight tendency for the distal barbules to decrease in 

 number, and for the proximals to increase as either extremitj' 

 of the feather is approached. In a barb taken from near the 

 base of the feather, for example, there are thirty-four distal 

 barbules per millimeter, and twenty-three proximals, while in 

 one of the barbs taken from the terminal portion of the feather 

 there are thirty distal barbules and twenty-six proximals per 

 millimeter. 



The proximal barbules (pi. 17, fig. 3) are characterized by 

 their comparatively stout form and long filamentous tips, the 

 latter constituting approximately one-half the total length, which 

 is from 0.90 to 0.95 millimeter. The dorsal recurved edge is 

 narrow, and its teeth at the bend are poorly developed. It 

 possesses four or five narrow ventral lobes, followed by two or 

 three incipient ones produced by mere folding. The nuclei of 

 the cells in the barbule show distinctly in a diagonal line running 

 from the basal ventral corner to near the dorsal edge, where the 

 filamentous tip has its origin. There are from eighteen to twenty 

 cells proximal to the filamentous tip. 



As explained by Strong (1902), the nuclei themselves dis- 

 appear from the barbules, but their position and form may 

 still be readily distinguished in many cases by the different 

 refractive properties of this region. Throughout this paper, 

 where the barbule nuclei are mentioned, it is these "ghosts" of 

 the nuclei to which reference is made. 



The distal barbules (pi. 17, fig. 3) are characterized by a 

 short base and very long tip, with a douljle row of well-developed 

 barbicels. The ventral lobes are short and stout, immediately 

 followed by four moderate booklets, which increase in length 

 distall.y. Beginning just beyond the booklets are two rows of 

 forward-curving barbicels, each pair representing the drawn- 



