372 Unwersity of California Publications in Zoology (Vou. 138 
In breast feathers barbules almost downy, the base very poorly 
developed and barbicels greatly reduced (pl. 32, fig. 85a). 
The facial dise of owls is the result of a series of very densely 
set and closely woven feathers. Barbs set 35 or 40 per centimeter 
and at a very acute angle with shaft, so that they le very close 
together, and barbules set about 32 and 38 per millimeter on prox- 
imal and distal vanules respectively. Distal barbules have short, 
stout, tapering bases and short pennula, the cells of which are short 
and crowded, so that the long, closely appressed ventral cilia are 
very much crowded. 
Caprimulgi.In Chordeiles virginianus distal barbules of inner 
vane of remiges resemble those of the Striges in form of their base, 
ventral teeth, and hooklets. Pennulum, as in the Striges, long, but 
never over 1 mm.; more slender than in owls, and only first 6 or 8 
cilia developed, the long series of conspicuous dorsal and ventral 
ones absent. 
In Podargus strigoides, filamentous types of distal barbules of 
inner vane still longer on distal third of barb, being sometimes 
almost 1.5 mm. long (pl. 32, fig. 87a). Interesting correlative 
modification in sigmoid backward curve of barbs to give more room 
for long overlapping pennula and to produce a softer feather. 
Distal barbules of outer vane in Chordeiles with rather short 
pennula with a well-developed series of ventral cilia (pl. 32, fig. 86a). 
Proximal barbules on inner vane, unlike owls, have rather 
short, stout pennula in Chordeiles, but in Podargus (pl. 32, fig. 87b) 
pennula are long. In the outer vane, proximals have a series of 
ventral cilia the more proximal of which are stout and hooked, the 
more distal ones slender and flexible (pl. 32, fig. 860). 
Body feathers have long, slender pennula, and weakened barbi- 
cels, mere simplifications of the remex type. 
Although in the great length of the pennula and resulting soft- 
ness of the plumage the Caprimulgi resemble the Striges, the details 
of structure, in so far as they differ in these suborders from that 
of typical Coraciiformes, are not the same, and it is only reasonable 
to suppose that the similarities are due to parallel evolution and 
that there is no closer relationship shown between these two groups 
than between either of them and other coraciiform groups. 
Trogonidae.—Prionotelus temnurus has structure much like 
Coracias, but especially characterized by form of ventral cilia. 
Latter very straight and inflexible, and conspicuously larger near 
