1916] Chandler: Structure of Feathers 359 
and the Pterocles, with the sand-grouse, on the other. The group 
is characterized by the great reduction of the plumules and the 
aftershaft. In the Columbae, which are the most specialized, in 
this regard, the plumules are entirely absent, and the aftershaft 
is absent or rudimentary. In the Pterocles, the plumules are evenly 
distributed, and the aftershaft is present, though small. 
a) Columba livia 
(1) Remexr 
Shaft much deeper than broad at superior umbilicus, for most 
of length about as broad as wide, with a narrow, median ventral 
groove, and striations on side, as in Laro-limicolae. Rami narrow, 
the ventral ridge inconspicuous. Vanules with very closely set bar- 
bules, the distals 45 per millimeter, the proximals about 35. 
Inner vane.—Distal barbules (pl. 29, fig. 64a) with short wide 
base, about 0.18 mm. long by 0.037 mm. wide, the ventral teeth 
very broad and triangular; nuclei in a strikingly diagonal line, 
even more so than in Galli. Pennulum little if any longer than 
base; more or less arched dorsad; hooklets small and_ slender, 
usually 6 in number, proximal 3 short, distal 3 progressively in- 
creasing in length; ventral cilia short, curved, subequal, well sep- 
arated from each other; dorsal cilia straight, spinelike, shorter 
than ventral ones, the proximal two not especially modified. Proz- 
ual barbules (pl. 29, fig. 646) relatively very short and broad, 
the base about 0.4 mm. long by 0.056 wide, with nuclei in conspicu- 
ously diagonal line as in distals. Ventral teeth usually 5, rather 
narrow and pointed, not elongated, but always evident. Pennulum 
very slender and filamentous, about half length of base. 
Outer vane.—Distal barbules (pl. 29, fig. 64c) much like those 
of inner vane, but, as shown by figure, whole barbule arched dorsad, 
instead of only the pennulum. Pennulum about as long as base, 
rather broad in lateral view. Hooklets 6 or 7 in number, small 
and slender. Ventral cilia as in distal barbules of inner vane, but 
a little shorter, dorsal cilia developed towards tip, but short and 
spinelike. Proximal barbules on basal portion of barbs similar to 
those of inner vane, towards tip ventral teeth become separated 
from one another, increase in number, sometimes to 7 or 8, and 
assume a stout curved form, intermediate between typical ventral 
teeth and typical cilia. 
(2) Other Feathers 
In Zenaidura macroura, used as type for description of back 
feathers, latter have distal barbules much like outer vane of remex, 
and proximals more like inner vane of remex. Distal barbules 
with short, broad base, broad ventral teeth, and relatively long 
pennulum, with short, blunt, ventral cilia (pl. 29, fig. 65a). Hook- 
lets characterized by presence of one or two prongs or horns on 
their distal side, as shown in the greatly magnified hooklet region 
of a distal barbule from a covert feather of Columba fasciata (pl. 
