FEET OF THE GREBES. 281 



one small one to the rear. There are always webs 

 of membrane between the front toes ; but in the 



species which swim only and do not dive, there is no 

 web to the hind one. Divers have it marginated 

 with a small web ; those birds which Cuvier styles 

 totipalms, or entire feet, have the hind toe much 

 longer and stronger, and included in the same web 

 with the anterior ones, and they have the whole foot 

 turned in a particular direction, the purpose of which 

 will be explained afterwards ; and there are some 

 genera which are in the habit of tipping the surface 

 of the water with their feet, while their bodies are 

 nearly or altogether supported by the wings in the 

 air, and these have the hind toe merely rudimental, and 

 the foot narrower in proportion than any of the others. 

 In order clearly to understand the uses of the dif- 

 ferent forms of web feet, it is necessary to consider 

 the other actions of the bird to which the foot must 

 be subservient, or at least with which it must be in 

 accordance. These actions are of course either walk- 



