342 University of California Ptiblications in Zoology [Vol. 13 



from the shaft, which remaiMS single for all the rest of its length. 

 In one ease 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- 

 teropode" group (Megapodidae and Cracidae) more strongly sug- 

 gesting the cuculoid birds, while the "Alectoropodes" (pheasants, 

 grouse, etc.) 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 

 oifshoot from a primitive gallinaceous stem. This will be more 

 fully discussed under Crj^pturiformes. 



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- 

 similarities 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. 



