SERRATED BILLS. 225 



their bills correspond. The common duck, which 

 may be taken as the average, has the bill most flat- 

 tened, and of the softest texture. These ducks have 

 the neck lengthened, and plunge the anterior part 

 of the body in the water till the axis is nearly per- 

 pendicular ; but they do not get so deep as to have 

 the joints of the tarsi immersed. 



The diving ducks have the neck and bill shorter 

 than the swimming ones ; but still they feed not in 

 the volume of the water, but at the bottom, and upon 

 mollusca, worms, spawn, and other soft substances, 

 and rarely if ever upon fish. This is the chief reason 

 why their flesh is much more juicy and finer flavoured 

 than that of the true aquatic feeders. 



But there is a gradation in the diving ducks, the 

 pochards, who resort more to the fresh waters, and 

 the rich mud banks on the estuaries of rivers, have 

 the bill much broader and flatter than the gannets, 

 which may be reckoned the most seaward of all the 

 duck tribe ; and there is a considerable trace' of the 

 fishy flavour in the flesh of the latter. 



The mero-ansers combine the characters of the 



Merganser— mergus serratus. 



diving ducks and the true divers ; they catch their 



prey in the water, and not at the bottom ; but they 



Q 



