342 University of California Publications in Zoology  {Vou. 138 
from the shaft, which remains single for all the rest of its length. 
In one case the barb was seen to be split for only a portion of its 
length, being fused into one at both base and tip. 
In peacocks the highly iridescent blue, green, and bronze colors 
are the result of barbules which are totally metamorphosed in both 
base and pennulum to produce color. 
e) Relationships 
According to the feather structure, the Galli are highly special- 
ized birds, the broad, ventral teeth of the distal barbules, the hooked 
ventral cilia of the proximals, and the nature of the down, being 
specializations and decidedly not primitive characters. The form 
of both distal and proximal barbules, as well as the form of the 
down, shows unmistakable affinity to that of the Columbae on the 
one hand, and the Cuculiformes on the other, the so-called ‘* Peris- 
oe) 
teropode’’ group (Megapodidae and Cracidae) more strongly sug- 
gesting the cuculoid birds, while the ‘‘Alectoropodes’’ (pheasants, 
erouse, ete.) are reminiscent of the Columbae. (Compare plates 24, 
29, and 30.) 
Unmistakable relationship is also shown to the Tinami, which, 
according to feather structure, should be considered as a specialized 
offshoot from a primitive gallinaceous stem. This will be more 
fully discussed under Crypturiformes. 
In some respects, namely in the form of the barbicels of the 
distal barbules of the remiges, some affinity to the Rallidae and 
other gruid forms is shown, but the nature of the body feathers is 
totally different, and it is more probable that the few striking 
sunilarities are rather to be interpreted as the result of parallel 
evolution. (Compare plate 24 with plate 25.) 
The relationship of the Galli with the Turnices will be discussed 
under the latter. 
f) Summary 
. The Galli are characterized as follows: 
(1) Plumules only in apteria. 
(2) Aftershaft variable, but when developed, with distinct and 
separate vanes. 
(3) In remiges, proximal barbules small as compared to distals, 
and both series very close set. 
