346 University of California Publications in Zoology [Vol. 13 



Ilooklets 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 harhules unique 

 (pi. 25, fig. 49&). Bases about 0.5 mm. long by 0.05 mm. wide, 

 very much curved transversely, so that dorsal part lies 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 Jatter 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 

 (pi. 25, fig. 49c). Outer bar formed by fusion of pennula of jjrox- 

 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 (pi. 25, 

 fig. 4:9d). 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 (pi. 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 frantzii, 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, Tinanius, 

 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, etc. 



