AQUATIC BIRDS. ANATID^E, OR DUCK TRIBE. 507 



from certain glands near the tail, so as to throw off the water 

 without being wetted by it ; and there is generally an under- 

 garment of down, which is especially thick beneath the body. 

 The food of these Birds usually consists of fish, mollusks, and 

 insects. They live much more upon or in the water, than on 

 land ; and resort to the shore chiefly for the purpose of building 

 their nests and rearing their young. One male usually asso- 

 ciates with several females, and leaves to them the cares of 

 incubation. The nest is rudely constructed, and is placed either 

 upon the ground, or upon the low vegetation in the neighbour- 

 hood of water ; and the young are hatched in a condition that 

 enables them immediately to run about and seek their own food. 

 This Order includes five families ; the ANATID^E, or Ducks ; 

 the COLYMBID^, or Divers ; the ALCID^J, or Auks; the LABID^E, 

 or Gulls; and the PELICANID^E, or Pelicans. 



454. The ANATID^E, or Duck tribe, are distinguished by the 

 breadth and depression of the bill, which is covered with a soft 

 sensitive skin ; and by the separation of the hind toe, which is 

 not included in the web. The bill is furnished with a set of 

 laminae or horny plates at the edge of each mandible ; the use 

 of which appears to be, to filter the fluid taken up by the bill, 

 allowing the water to escape, and retaining the solid substances 

 included in it, thus serving very much the same purpose as 

 the sieve of Whalebone in the mouth of the Whale ( 214). 

 The selection and appropriation of the food is further aided by 

 the tongue ; which, instead of being slender and horny, is large 

 and fleshy. The gizzard is strong and muscular, and is lined 

 in many species by a very thick, tough, and almost horny coat, 

 so as to be capable of grinding down the shells of mussels and 

 other mollusks on which they feed. The Anatidse are dispersed 

 over every part of the globe, and are usually more or less migra- 

 tory in their habits. Their flight is vigorous and rapid ; and it 

 is generally at a high elevation. As connecting this family 

 with the preceding order, we must notice the extraordinary 

 Flamingo; which, from the length of its legs and neck, would 

 seem to be a Wading Bird ; but which, in the complete palma- 

 tion (webbing) of its feet, and in the form and structure 



LL2 



