118 BRITISH BIRDS. 



flight-feathers are bent back, the bird apparently resisting the rush 

 of air that would carry the wing backward and upward, or, possibly, 

 •even lowering the further part of the wing — a kind of continuation of 

 the downstroke in which only the further half of the wing takes part. 

 But, are the muscles required for such a stroke to be found ? Professor 



Marey in his Voldes Oiseaux (pp. 160, 268, and in the plate at the end) 

 has figures which show the same astonishing phenomenon — they make 

 it clear that it occurs during the upstroke — but, as far as I know, he 

 nowhere makes any comment. F. W. Headley. 



