Chap. VI. TEANSITIONAL HABITS. 185 



berardi, in its general habits, in its astonishing power of 

 diving, its manner of swimming, and of flying when 

 unwillingly it takes flight, would be mistaken by any 

 one for an auk or grebe ; nevertheless, it is essentially 

 a petrel, but with many parts of its organisation pro- 

 foundly modified. On the other hand, the acutest 

 observer by examining the dead body of the water-ouzel 

 would never have suspected its sub-aquatic habits ; yet 

 this anomalous member of the strictly terrestrial thrush 

 family wholly subsists by diving, — grasping the stones 

 with its feet and using its wings under water. 



He who believes that each being has been created as 

 we now see it, must occasionally have felt surprise when 

 he has met with an animal having habits and structure 

 not at all in agreement. What can be plainer than 

 that the webbed feet of ducks and geese are formed 

 for swimming ? yet there are upland geese with webbed 

 feet which rarely or never go near the water ; and no 

 one except Audubon has seen the frigate-bird, which 

 has all its four toes webbed, alight on the surface of the 

 sea. On the other hand, grebes and coots are emi- 

 nently aquatic, although their toes are only bordered 

 by membrane. What seems plainer than that the long 

 toes of grallatores are formed for walking over swamps 

 and floating plants, yet the water-hen is nearly as aquatic 

 as the coot ; and the landrail nearly as terrestrial as the 

 quail or partridge. In such cases, and many others 

 could be given, habits have changed without a cor- 

 responding change of structure. The webbed feet of the 

 upland goose may be said to have become rudimentary 

 in function, though not in structure. In the frigate- 

 bird, the deeply-scooped membrane between the toes 

 shows that structure has begun to change. 



He who believes in separate and innumerable acts of 

 creation will say, that in these cases it has pleased the 



