1916] Chandler: Structure of Feathers 319 
markably short, about half length of base, very broad proximally, 
and tapering rapidly to tip; pigment deeper ventral to nuclei than 
dorsal to them, reverse being more frequently true in other birds. 
Outer vane—Distal barbules differ only in absence of dorsal 
cilia, except a few terminal rudimentary ones (pl. 20, fig. 23¢). 
Proximals, unlike those of any birds so far studied except peli- 
cans, differ only slightly from those of inner vane, being somewhat 
smaller, their form exactly similar except that ventral teeth are 
slightly longer, with tendency to become hooklike, but even at tip 
of barbs not increasing in numbers and forming a series of ventral 
barbicels. 
(2) Other Feathers 
Back feathers have same structure as outer vane of remiges 
except that small dorsal cilia are sometimes developed on distal 
barbules near the base of more proximal barbs. In breast feathers 
structure not essentially different. Distals (pl. 20, fig. 23d) more 
elongate, and dorsal cilia, except at proximal end of pennulum, 
better developed. Proximal barbules of exactly same type as in 
remiges, in neither distal nor proximal barbules any tendency what- 
ever for development of flexules. 
b) Other Types 
Ciconia ciconia has a very similar structure of its feathers. 
The chief difference is in the relative narrowness of the proximal 
barbules. 
Leptoptilus dubius has a slight modification of the structure of 
distal barbules as compared with those of Mycteria. The first two 
dorsal barbicels of distal barbules of the inner vane (pl. 20, fig. 24a) 
are stout and spinelike as usual, but are very much closer together 
and are not followed by a series of less specialized cilia, thus approach- 
ing more closely to the heron type. On the outer vane the pennulum 
of distal barbules is relatively short and furnished with an even series 
of short blunt dorsal cilia (pl. 20, fig. 246). The under tail cov- 
erts of Leptoptilus deserve special mention as they are the source 
of the famous ‘‘marabou’’ feathers of commerce. These feathers 
are furnished with stiff, heavy shafts, but have the entire feather 
downy in structure, a condition seldom found in contour feathers, 
except occasionally on a very weakly developed breast or belly 
feather. 
In Plegadis guarauna, or scarlet ibis, there is a very striking 
modification in the distal barbules to deepen the scarlet color-effect 
(pl. 20, fig. 26a). As will be seen from this figure, both base and 
pennulum are profoundly transformed, and all the barbicels except 
the hooklets are lost or greatly changed. Both base and pennulum 
