ACTION OF THE GOOSE'S FOOT. 285 



feet more nearly in the vertical plane than the divers. 

 But there is, even in them, a very beautiful action 

 of the foot, brought about by the mere bending of 

 the leg, without any additional exertion of muscular 

 power. The moment that they begin to draw it for- 

 ward, after it has made the stroke, it begins to con- 

 tract, by the bending of the tarsal joint pulling the 

 tendon. The surface which the foot presents to the 

 water in the direction toward which it is pulled, is 

 thus not only constantly diminishing, but it is convex 

 in its form, and yielding as the joints are relaxed, so 

 that it " comes home" through the water with very 

 little effort on the part of the bird. When, however, 

 it begins to act in the taking of the stroke, it presents 

 the concave side, and that side keeps enlarging till, 

 at the time when the stroke is given, it has attained 

 its greatest breadth. It then comes to nearly a 

 horizontal position of the feet, and from this it is 

 drawn forwards with not much more breadth than 

 the edge to the water. 



This foot is exactly a paddle, only it acts better 

 both on the stroke and the return than any paddle 

 which man can construct. No doubt the paddle 

 which man uses is recovered through the air, and 

 thus the resistance of the water is wholly avoided 

 during that part of the operation. But still the exer- 

 tion which has to be made in raising the paddle is 

 much greater in proportion to the effect- produced 

 than that made by the foot. 



The swan, though nearly or altogether equal to the 

 goose in flight, is much less upon land in its ordinary 

 habit, and it is accordingly better adapted for swim- 

 ming, and, as a necessary consequence, a worse walker. 

 Swans, indeed, stand in much the same relation to 

 geese (taking them on the average) as the diving 



