228 BILLS OF THE 



some which depend more on the sea than on the 

 land ; but they are land birds, clutching^ their prey 

 with the feet, and altogether unfit for swimming. 

 Some of the sea-birds also prowl along the shores, 

 and eat the eggs and the unfledged young of other 

 birds ; and there are some which rob others of the 

 prey they have taken, by making them disgorge it 

 from their stomachs ; these last are birds of strong 

 bill and powerful wing, but still their characters, 

 though different from those of all land-birds, resemble 

 those of the omnivora more than the accipitres. 



The birds which make the most natural transition 

 from the herons and other tribes which fish in the 

 fresh water, are those which Cuvier calls toiipalmi, 

 or entire-feeted, from their having all the toes in- 

 cluded in one web. These, though not the birds to 

 which the name of " sea-eagles" is usually given, are 

 the ones which in their habit much resemble the 

 eagles ; they dash into the water, and seize that prey 

 which they have previously discovered by the eye, 

 only they seize it with the bill. But most, if not all 

 of them have a double habit ; as they also catch prej" 

 while swimming on the surface ; but they live more 

 upon live fish, and less upon the offal of the sea than 

 most of the other races. 



The bill of the gannet, of which a figure is given, 

 may be considered as the most characteristic of these 

 bills. 



It will be seen that it is stout at the base, nearly 

 straight, has both mandibles serrated, and both tips 

 a very little bent. Its outline is that which gives the 

 greatest stiffness with the same quantity of materials ; 

 but the upper mandible, as in all bills which act very 

 powerfully, has a little motion. When the bird de- 

 scends with velocity, this bill transfixes like a spear, 



