CREATION BY LAW. 269 



we might suppose that there is a constant Correla- 

 tion of Growth between webbed feet and spoon- 

 shaped Bills. But the real and efficient Correlation 

 of Growth in this case is not between the spoon- 

 bill and the web-foot, but between both of these and 

 certain external conditions of life. The web-foot is 

 correlated to an aquatic habitat; and the spoon 

 bill is correlated to spoon-food. And accordingly 

 this association of form in foot and bill is at 

 once dissolved where different external functions 

 require a separation. In the Gulls, the Fulmars, 

 and the Petrels the web-foot is retained, because 

 action upon the element of water is still required ; 

 but the correlated form of Bill vanishes, and shapes 

 altogether different are given, — shapes adapted, 

 that is correlated, to different kinds of food, and 

 to different methods of capture. 



Again, there is another great family of Birds 

 where some of the same forms are correlated with 

 other forms entirely different, because of the dif- 

 ferent external Correlations which are required 

 by Function. In the Divers the web-foot is 

 mounted upon a flattened leg-bone, with the 

 sharp edge set " fore and aft." Now what is this 



