328 Unwersity of California Publications in Zoology Vor. 18 
appressed. Dorsal cilia forming a well-developed series, basal ones 
stouter and spinelike, but not as strongly contrasted with others 
as in Ciconiae. Proximal barbules (pl. 21, fig. 28d) also thin and 
filmlike, with little pigment; base unusually slender, about 0.65 
by 0.04 mm. Proximal two ventral teeth broad, lobate, and blunt, 
followed by two or three narrow and pointed ones; pennulum little 
shorter than base, with rudimentary barbicels always showing. 
Outer vane—Distal barbules (pl. 21, fig. 28e) with drawn-out 
points of ventral teeth more prominent; hooklets even more slender, 
and increased in number; dorsal barbicels absent. Proximal bar- 
bules on outer portion of barb with ventral teeth proliferated and 
transformed into straight ventral barbicels, resembling teeth of a 
comb (pl. 21, fig. 28f). 
(2) Other Feathers 
As in nearly all ducks, greater wing coverts form a speculum 
of different color from rest of wing, in this case deep bluish violet. 
For production of this color, as of other metallic colors, e. g., blues 
and greens of various species, the pennula are transformed into 
flattened refrangent surfaces (pl. 21, fig. 287) with constrictions 
between cells, and fine, longitudinal striations on cells, which are 
deeply pigmented with black. Base and hooklet region considerably 
reduced in these metamorphosed barbules. Barbules of inner vane 
of speculum feathers, and proximals of outer vane also, unmodified. 
As described at close of Part I (p. 279), modifications of distal 
barbules are absent in albinos. 
Body feathers rather loose in texture, due largely to fact that 
bases of barbules le in vertical plane, leaving wide spaces between 
them. Ventral teeth of distal barbules greatly reduced, but slender, 
subequal cilia still numerous and well formed. Just distal to hook- 
let region, pennulum twists so that ventral cilia come to project 
dorsally. Proximals have slender, tapering bases, inconspicuous 
ventral teeth and rudimentary prong-like cilia. The poorly de- 
veloped tail feathers intermediate in form between remiges and body 
feathers. Their form is shown by plate 21, figures 28g and h. 
b) Other Types 
The minute structure of the feathers is remarkably constant in 
all the members of the Anseres. Nettion carolinense is perhaps 
slightly more typical of the group in that the ventral teeth of the 
distal barbules are greatly elongated and slender, as shown in plate 
21, figure 29a. Marila, Mergus, Querquedula and other genera are 
almost identical with Nettion. 
Branta, like Anas, has the ventral teeth of the distals somewhat 
shorter, while some of the feathers have the pennula of the distals 
of the outer vane elongated with long brushlike cilia to produce the 
characteristic plush-like effect. Chen very closely resembles Branta, 
