They are square-topped, and are edged with translucent, hardish tissue, as if for crushing food.

The edges of the lower mandible are crossed by numerous fine ridges, which project very little.

Although the beak is thus very inferior as a sifter to that of a shoveller, yet this bird, as every one knows, constantly uses it for this purpose.

There are other species, as I hear from Mr.Salvin, in which the lamellae are considerably less developed than in the common duck; but I do not know whether they use their beaks for sifting the water.
Turning to another group of the same family.

In the Egyptian goose (Chenalopex) the beak closely resembles that of the common duck; but the lamellae are not so numerous, nor so distinct from each other, nor do they project so much inward; yet this goose, as I am informed by Mr.E.
Bartlett, "uses its bill like a duck by throwing the water out at the corners." Its chief food, however, is grass, which it crops like the common goose.