642 ON THE NESTLING FEATHERS OP THE MALLARD. 



Fig. 26. Emu feathers of the first, second, and third generations. The tip of the 

 aftershaft of the feather of the third generation is continuous with the 

 rhachis of the aftershaft of the feather of the second generation. 

 27. In this specimen the tip of the aftershaft of the second generation feather 

 had lost its connection with the protoptile, and the tip of the aftershaft 

 of the third generation feather had lost its connection with the " calamus " 

 of the feather of the second generation. 



Plate VIII. 



Fig. 28, Emu protoptile and a developing feather of the second generation, the 

 aftershaft of which is repi'esented bj^ two barbs. X 5. 



29. Developing feather from rump of 18 da.ys' Mallard duckling. This feather 



consists of two portions, one, the larger, representing a shaft, and one 

 representing an aftershaft, connected lilje the Emu feather given in 

 tig. 28, to the protoptile by two barbs. 



30. Breast feathers from an adult moulting King Penguin. The growing 



feather consists of a shaft and an aftershaft connected by their tips with 

 the calamus of the feather about to be shed. 



31. In this figure the shaft of the new feather has been removed to show the 



connection between the developing aftershaft and the old feather. 



Plate IX. 



Fig. 32. Grouse feather with an aftershaft as long and as complex as the shaft. 



33. A protoptile and a developing true feather from a young Ptarmigan. The 



part of the developing feather with a distinct rhachis represents the 

 shaft, the part in which a rhachis has not yet appeared represents an 

 aftershaft. 



34. Calamus and aftershaft of the wang-quill of a Grouse. 



35. Feather of a fowl of the Silky breed with an aftershaft as long as the shaft. 



Plate X. 



Figs. 36 & 37. Feather from a nestling Black Guillemot. 36, represents the shaft, 

 and thirteen barbs of the protoptile. 37, the four remaining protoptile 

 barbs connected with the rhachis of the aftershaft which was detached 

 along with the calamus. 

 38. Protoptile of a Wood Pigeon connected to the tip of a true feather hy a 

 vestige of a raesoptile. The pulp projects from the tip of the teleoptile. 

 Note that the barbs resemble hairs, have no barbules. 



