390 



The Bird 



case, no attempt is made to proceed in a straight Hne. 

 In a pool only thirty feet square I have seen a duck 

 revolving thus for an hour or more at a time, impelled 

 with slow, rhythmical (and apparently reflex) strokes. We 



Fig. 306.— Foot of Rlark-nopked Swan. 



can imagine that such a habit would sometimes be of much 

 advantage to a wild bird, enabling it to keep away from 

 enemies on the shore and yet at the same time secure rest. 

 The name Steganopodes is applied to the gannets, 

 pelicans, snake-birds, tropic-birds, and cormorants, be- 



