NESTLING I^EATHfiRS 01? THE MALLARD. 



629 



rhacliis of the aftershaft, after giving oft' several pairs of barbs 

 but without appreciably increasing in width, becomes continuous 

 with the rhachis of the aftei'shaft of the feather of the third 

 generation (PI. YII. fig. 26). When (as was the case in the 

 specimen represented in PI. VII. fig. 27) the two connecting bands 

 naturally separate from each other, it is impossible to escape 



Text-fiafure 1 1. 



In tliis diagram the structure and relations of the feathers forming the first three 

 generations in the Emu are indicated, sh. 1, shaft, and af. 1, aftershaft of pro- 

 toptile. s7i. 2, shaft, and af. 2, aftershaft of a feather of the second generation. 

 sh. 3, shaft, and af. 3, aftershaft of a feather of the third generation. The 

 aftershaft of the protoptile is from the outset free, but the tip of the aftershaft 

 of the feather of the second generation is, to start with, continuous with the 

 protoptile aftershaft, and the aftershaft of the feather of the third generation is 

 also for a time continuous with the aftershaft of the second generation feather — 

 according to Gadow the tip of the aftershaft of the second generation feather is 

 a forward prolongation from the calamus which is never during development 

 connected by its tip with the " calamus " of the protoptile or first generation 

 feather. 



from the conclusion that, just as the aftershaft of the second 

 feather of the Emu is connected at the outset with the proto- 

 ptile, the aftershaft of the feather of the third generation is 

 connected with the feather of the second generation. 



The feathers represented in PI. YII. figs. 26 &, 27 (from a seven 



