1914] Chandler: Feathers of Circus hudsoniiis 347 



eeeding rows. The aftershaft is poorly developed, its shaft being 

 very short, and the barbs springing more or less fanlike from 

 a broad base. The lesser coverts on the radial edge of the wing 

 are strongly curved in order to fit firmly, and give the smooth, 

 sharp line for cutting the wind. The upper and lower coverts of 

 this region curve in opposite directions, both of them away 

 from the margin, those directly on the edge being quite narrow, 

 and but slightly curved. 



HUMERALS 



The continuation of the le.sser coverts on the humerus gives 

 ri.se to a series of four or five large feathers which lie normally 

 in an antero-posterior series, on account of the usual position of 

 the humerus. These feathers, known as tertiaries or humerals, 

 are remex-like in form, and devoid of aftershafts. Their minute 

 structure is very much the same as that of the remiges, but 

 they differ in the fact that the more distal barbs of both vanes 

 have, toward their tips, proximal barbiiles with more or less 

 booklet-like spines, quite similar to those of the distal part of 

 the outer vane of the remiges. 



Middle and Lesser Under Coverts 



The under wing coverts, with the exception of the greater 

 coverts, which have already been described, lie as do the upper 

 coverts, with their upper side exposed and the umbilicus toward 

 the body of the bird. A small, downy aftershaft is present. The 

 barbs of the basal third of the feathers are downy in nature at 

 their tips, the most basal ones being entirely downy. There are 

 twenty-three barbs per centimeter on each side of the inner vane, 

 and twenty-one on the outer. The distal and proximal barbules 

 average only twenty-one and fifteen per millimeter respectively, 

 and, as the booklets and grooves are very weakly developed, 

 there is a tendency for the barbs to break apart except in the 

 region near the shaft. The distal barbules have two or three 

 very weak booklets, followed by a single series of weak barbicels 

 on a long slender tip. The proximal barbules taper to a slender 

 tip which bears a series of small barbicels. 



