DUCKS. 93 



ture have probably a connection with the loudness 

 or intonation of the voice. The gizzard is large 

 and muscular, and especially in those species 

 which are more terrestrial, living largely on grain. 

 They mostly nestle on the ground, but some on 

 trees, and lay numerous spotless eggs ; the young 

 are at first covered with down, and are able to 

 run and to swim as soon as they are hatched. 



The remarkable laminated structure at the 

 edges of the mandibles in the birds of this 

 Family, and its connection with their habit of 

 feeding, are thus commented on by Mr. Swainson. 

 " The inconceivable multitudes of minute ani- 

 mals, which swarm in the northern seas, and the 

 equally numerous profusion inhabiting the sides 

 of rivers and fresh waters, would be without any 

 effectual check upon their increase, but for the 

 Family of the Ducks. By means of their broad 

 beak, as they feed upon very small and soft sub- 

 stances, they capture, at one effort, considerable 

 numbers. .Strength of substance in this member 

 is unnecessary ; the beak is therefore compara- 

 tively feeble, but great breadth is obviously essen- 

 tial to the nature of their food. As these small 

 insects, also, which constitute the chief food of 

 the Anatidce, live principally beneath the surface 

 of the mud, it is clear that the beak should be so 

 formed as that the bird should have the power of 

 separating its nourishment from that which would 

 be detrimental to the stomach. The use of the 

 laminse thus becomes apparent ; the offensive 

 matter is ejected between their interstices, which, 

 however, are not sufficiently wide to admit the 

 passage of the insect-food at the same time. The 

 mouthful of stuff brought from the bottom is, as 



