356 HISTORY OF 



When men swim, they do not open the fingers, 

 so as to let the fluid pass through them ; but 

 closing them together, present one broad surface 

 to beat back the water, and thus push their bodies 

 along. What man performs by art, nature has 

 supplied to water fowl, and by broad skins has 

 webbed their toes together, so that they expand 

 two broad oars to the water ; and thus, moving 

 them alternately, with the greatest ease paddle 

 along. We must observe also, that the toes are 

 so contrived, that, as they strike backward, their 

 broadest hollow surface beats the water ; but as 

 they gather them in again for a second blow, 

 their front surface contracts, and does not impede 

 the bird's progressive motion. 



As their toes are webbed in the most convenient 

 manner, so are their legs also made most fitly for 

 swift progression in the water. The legs of all 

 are short, except the three birds described in a 

 former chapter j namely, the flamingo, the avo- 

 setta, and the corrira ; all which, for that reason, 

 I have thought proper to rank among the crane 

 kind, as they make little use of their toes in 

 swimming. Except these, all web-footed birds 

 have very short legs ; and these strike, while they 

 swim, with great facility. Were the leg long, 

 it would act like a lever whose prop is placed to 

 a disadvantage ; its motions would be slow, and 

 the labour of moving it considerable. For this 

 reason, the very few birds whose webbed feet are 

 long, never make use of them in swimming : the 

 web at the bottom seems only of service as a 

 broad base, to prevent them from sinking while 



