1916] Chandler: Structure of Feathers 373 
tip than near base of pennulum. No dorsal cilia, even on inner 
vane, and hooklets moderately long, only 3 in number (pl. 31, 
figs. 80a, 80b). Proximal barbules of outer vane, on terminal por- 
tion of barbs, have ventral teeth increased in number, but remaining 
blunt, and appressed to barb (pl. 31, fig. 80c), well-developed 
ventral barbicels never being formed. Body feathers, where not 
modified for color, with barbules similar to those of remiges, but 
simpler. 
Cypselidae—tIn Cypseloides niger, on inner vane of remiges, 
distal barbules have base of typical coraciiform shape, but the 
ventral tooth, usually single and relatively large, with its tip bent 
sharply down, giving it a blunt appearance distally. Pennulum 
with more proximal dorsal cilia developed and stout in form on 
barbules on outer portion of barbs, on the inner portion only the 
ventral ones present; these moderate in size and curved as in 
Coracias, pennulum usually breaking off a little distal to hooklets. 
Proximal barbules with short, broad, tapering bases, the ventral 
edge more or less scalloped, and pennulum rather heavy, about as 
long as bases. Body feathers have distal barbules with ventral tooth 
larger at tip than at base as in some passerine birds. Chaetura 
differs in having broader bases of the distal barbules and rather 
reduced hooklets. 
Trochilidae—In remex of Selasphorus rufus, distal barbules are 
characterized by disproportionate size of base and relatively large 
ventral teeth. Proportionate to the size of the base, the hooklet 
region of the pennulum and hooklets are exceedingly small (pl. 32, 
figs. 88a and b). In all feathers examined of this species and of 
several other species the pennulum was broken off one or two cells 
beyond the hooklets as shown in the figures. The base measures 
about 0.18 by 0.025 mm., while the pennulum, up to the point. 
where usually broken off, is only one-fifth as long. The proximal 
barbules have short, broad, tapering bases, with the ventral edge 
scalloped, ventral teeth inconspicuous and pennulum stout, about 
as long as base (pl. 32, fig. 88c). 
Body feathers have barbs with approximately equal vanules, the 
barbules very numerous, about 45 per mm. on each side, with their 
broad surface exposed, but not in contact on feathers without color 
modifications. Pennula of barbules of both vanules broad and thin, 
lying in a vertical plane and turned at such an angle with the base 
as to be parallel with the ramus (see Beebe, 1906, fig. 27). This 
