xvi HISTORY OF THE OSTRICH 393 



(4) Rudimentary hooklcts or barbiccls have been 

 found in the wing-feathers of the Rhea and some of the 

 allied birds. This is a most important fact. If they 

 did not help in flight, by making the feathers im- 

 pervious to air, it is difficult to imagine what purpose 

 they can have served. 



(5) The fusion of the hand-bones in the Ostrich 

 shows that the wing-feathers were once stronger and 

 that the wing had work to do. 



(6) Definite apteria have been found in some birds 

 of the Ostrich kind. Even if this were not the case, we 

 might urge that the point is one of little importance, 

 since the Penguin has none. 



On the whole the arguments seem to show that the 

 progenitors of the Ostrich were birds of flight. But 

 the question is a difficult one. 1 



1 The whole question is discussed in Fiirbringer's Untersuch- 

 ungen zicr Morphologic and Systematik der Vogel, p. 1481. See 

 also Bronn's Thicr-Reich, vol. " Aves." 



