306 



ZOOLOGY. 



would seem that so long as the feather grows, or is being 

 developed, the capsule increases in length, and that in pro- 

 portion as its base elongates, the extremity dies, and dries up 

 so soon as it has formed the corresponding portion of this 

 appendage. Each of these small apparatuses is composed of a 

 cylindrical sheath, covered internally by two tunics, united by 

 oblique septa, and of a central bulb. The substance of the 

 feather is formed on the surface of the bulb, and to form the 



Fig. 282. Galeated Cassowary. 



barbs it is moulded, as it were, into the spaces which the 

 small septa leave between them. In the corresponding por- 

 tion of the stalk, the bulb is in relation with its inferior 

 surface, and dies; but where the stalk of the feather is 

 tubular, the lamina of borny matter which the bulb pro- 

 duces turns entirely round it, and envelopes it completely. 

 Nevertheless, the bulb, as it fulfils these functions, still 

 dries up and dies, and thus withering successively it forms 

 a series of membranous cones set into each other, which 



