346 University of California Publications in Zoology ‘Vou. 138 
Hooklets short, subequal in length, and extremely numerous, 
usually 8. Proximal 3 or 4 ventral cilia moderate, not curved, more 
or less appressed, more distal ones rudimentary. Dorsal cilia 
strikingly similar to neural spines of dorsal vertebrae of a dog, in 
relative size, shape, and general direction, the first two or three 
rapidly increasing in size, and progressively pointing more distally, 
the remaining ones slowly decreasing again but continuing to pro- 
ject at a smaller and smaller angle. Proximal barbules unique 
(pl. 25, fig. 49b). Bases about 0.5 mm. long by 0.05 mm. wide, 
very much curved transversely, so that dorsal part les almost 
parallel with ventral part, a device taking the place of a dorsal 
flange. Pennula completely fused into a solid bar lying parallel 
with ramus, the ventral teeth, one or two in number, projecting 
ventrally just proximal to the bar; dorsal teeth absent. Hooklets 
of distals hook under recurved dorsal edge of proximals, and fused 
pennula of latter prevent their slipping out under strain. 
Outer Vane—Structure of distal barbules exactly same as in 
inner vane, except the less development of more basal dorsal cilia 
(pl. 25, fig. 49c). Outer bar formed by fusion of pennula of prox- 
imals same as on inner vane for over nine-tenths of vanule, the 
proximal barbules of the distal 2 or 3 millimeters with well- 
developed, strongly hooked barbicels on free pennulum, as in Galli. 
(2) Other Feathers 
The back feathers with distal barbules with rather elongate, 
rectangular base, ventral tooth single, much reduced, pennulum with 
broad face in nearly same plane as base, hooklets reduced to 3 or 4, 
other barbicels short, blunt, and more or less rudimentary (pl. 25, 
fig. 49d). Proximal barbules differing only in having a narrower 
base, which stands vertically, the bar of fused pennula carried to 
very tip on both vanes in well-developed feathers (pl. 25, fig. 49e). 
In looser ones, and in breast feathers, pennula of proximal barbules 
imperfectly fused on distal half of barb, and on distal third no 
fusion whatever. Distal barbules of breast feathers like those of 
back feathers, except that pennulum has long filamentous tip. 
b) Other Types 
All species of tinamous are strikingly similar in the structure of 
their feathers. The remiges of Nothocercus frantzu, for instance, 
differ only in the slightly longer pennulum of the distal barbules, 
and the more restricted area of free barbicelled proximals on the 
outer vane. The back and breast feathers have been examined in 
different species of five different genera (Nothocercus, Tinamus, 
Rhynchotus, Nothura, and Calopezus), and in all the structure of 
the barbules is remarkably similar, differing only in the relative 
length of the pennula of the distal barbules, development of ventral 
cilia, ete. 
