354 University of California Publications in Zoology [Vol. 11 



The feathers of the crown are shorter and more compact 

 than the nape feathers, the down portion is greatly reduced, the 

 barbs are about the same in number as on the nape feathers, 

 and the barbules (pi. 19, figs. 16 and 17) are equally numerous, 

 there being twenty-two proximals and twenty-seven distals per 

 millimeter. From the lower back to the crown there is a gradual 

 shortening of the barbules, as might be expected from the closer 

 approximation of the barbs. The average length of the barbules 

 of a crown feather is 0.5 millimeters or less for the distals, and 

 about 0.75 for the proximals. 



The most caudal row of back feathers, modified to serve as 

 upper tail coverts, may be distinguished from the other back 

 feathers by the much stouter shafts, and the firmness of the 

 vanes. The shaft is over a millimeter broad at the umbilicus, 

 and is conspicuously arched in order to fit down firmly against 

 the quills of the tail feathers. The compactness of the vanes is 

 due to the firm interlocking of the barbules, and to the fairly 

 numerous barbs, there being twenty-one and thirty-one per 

 centimeter on the outer and inner vanes respectively. The distal 

 barbules, twenty-eight per millimeter, are very well developed, 

 having broad bases and well-formed booklets, followed by a 

 single series of even, medium-sized barbicels. The proximal 

 barbules, twenty-one per millimeter, are of typical form, with 

 a broad base, and a well-marked bend before the stout tip. The 

 aftershaft in these feathers is insignificant. 



Under Parts 



The feathers of the under parts differ from those of the back 

 only in minor details. The feathers from the lower breast to the 

 facial ruff are very similar to the corresponding feathers of the 

 back except that there are two or three fewer barbules per 

 millimeter, the result being a somewhat looser and more fluffy 

 feather. The lower breast feathers have the downy portion very 

 highly developed, and the downy barbules, some of them four 

 millimeters in length, are crowded together on the shaft, thirty 

 or more per millimeter. 



The upper breast feathers differ from the lower ones but 

 slightly. They are shorter and much more curved, the shaft 



