372 University of California Publications in Zoology [Vol. 13 



In breast feathers barbules almost downy, the base very poorly 

 developed and barbicels greatly reduced (pi. 32, fig. 85a). 



The facial disc 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 lie 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 booklets. 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 (pi. 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 (pi. 32, fig. 86a). 

 Proximal barbules on inner vane, unlike owls, have rather 

 short, stout pennula in Chordeiles, but in Podargus (pi. 32, fig. 87&) 

 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 (pi. 32, fig, 86&). 



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 



